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Volume 9 Issue 2 (2018) ISSN 2228-9860 eISSN 1906-9642

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AN INVESTIGATION AND TEST OF NATURAL RUBBER LATEX SOIL CEMENT ROAD BEHAVIORS OF THE COMPOSITE SLAB COMPOSED OF CORRUGATED STEEL SHEET AND CONCRETE TOPPING USING NONLINEAR FINITE ELEMENT ANALYSIS HOME OWNERSHIP IN LOW-COST HOUSES IN PENANG, MALAYSIA THE IMPACT OF DAYLIGHTINGARTIFICIAL LIGHTING INTEGRATION ON BUILDING OCCUPANTS’ HEALTH AND PERFORMANCE EFFECTIVENESS OF SUBTERRANEAN HEAT USE IN AN EARTH TUBE COMMUNITY HOUSE EFFICACY OF DOUBLE SKIN FAÇADE ON ENERGY CONSUMPTION IN OFFICE BUILDINGS IN PHNOM PENH CITY A STUDY OF BUILDING RENOVATION TO BE A NET ZERO ENERGY BUILDING: CASE STUDY OF ENERGY MANAGEMENT AND INNOVATION OFFICE, BUILDING AND FACILITY DIVISION, KHON KAEN UNIVERSITY

Cover photo is Portable Skid Resistance Tester (British Pendulum Tester (BPT) of a trial batch demonstration specimen from the mix of natural rubber latex soil cement, in a paper published in this issue, entitled AN INVESTIGATION AND TEST OF NATURAL RUBBER LATEX SOIL CEMENT ROAD, by Pinwiset et al.

2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies.

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies http://TuEngr.com

International Editorial Board

Editor-in-Chief Ahmad Sanusi Hassan, PhD Professor UniversitiSains Malaysia, MALAYSIA

Executive Editor BoonsapWitchayangkoon, PhD Associate Professor Thammasat University, THAILAND

Editorial Board:

Assoc. Prof. Dr. Mohamed Gadi (University of Nottingham, UNITED KINGDOM) Professor Dr.Hitoshi YAMADA (Yokohama National University, JAPAN) Professor Dr. Chuen-Sheng Cheng (Yuan Ze University, TAIWAN ) Emeritus Professor Dr.Mikio SATOMURA (Shizuoka University, JAPAN) Professor Dr.Chuen-Sheng Cheng (Yuan Ze University, TAIWAN) Emeritus Professor Dr.Mike Jenks (Oxford Brookes University, UNITED KINGDOM ) Professor Dr.INyomanPujawan (SepuluhNopember Institute of Technology, INDONESIA) Professor Dr.Toshio YOSHII (EHIME University, JAPAN) Professor Dr.NevenDuić (University of Zagreb, CROATIA) Professor Dr.Dewan Muhammad Nuruzzaman (University Malaysia Pahang MALAYSIA) Professor Dr.Masato SAITOH (Saitama University, JAPAN)

Scientificand Technical Committee & Editorial Review Board on Engineering, Technologies and Applied Sciences:

Associate Prof. Dr. Paulo Cesar Lima Segantine (University of São Paulo, BRASIL) Associate Prof. Dr. Kurt B. Wurm (New Mexico State University, USA ) Associate Prof. Dr. Truong Vu Bang Giang (Vietnam National University, Hanoi, VIETNAM ) Associate Prof. Dr. Fatemeh Khozaei (Islamic Azad University Kerman Branch, IRAN) Associate Prof.Dr. Zoe D. Ziaka (International Hellenic University, GREECE ) Associate Prof.Dr.Junji SHIKATA (Yokohama National University, JAPAN) Assistant Prof.Dr.Akeel Noori Abdul Hameed (University of Sharjah, UAE) Dr. David Kuria (Kimathi University College of Technology, KENYA ) Dr. Mazran bin Ismail (Universiti Sains Malaysia, MALAYSIA ) Dr. Salahaddin Yasin Baper (Salahaddin University - Hawler, IRAQ ) Dr. Foong Swee Yeok (Universiti Sains Malaysia, MALAYSIA) Dr.Azusa FUKUSHIMA (Kobe Gakuin University, JAPAN) Yasser Arab (Ittihad Private University, SYRIA)

:: International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies Volume 9 Issue 2 (2018) http://TuEngr.com

ISSN 2228-9860 eISSN 1906-9642

FEATURE PEER-REVIEWED ARTICLES AN INVESTIGATION AND TEST OF NATURAL RUBBER LATEX SOIL CEMENT ROAD

BEHAVIORS OF THE COMPOSITE SLAB COMPOSED OF CORRUGATED STEEL SHEET AND CONCRETE TOPPING USING NONLINEAR FINITE ELEMENT ANALYSIS

HOME OWNERSHIP IN LOW-COST HOUSES IN PENANG, MALAYSIA

THE IMPACT OF DAYLIGHTING-ARTIFICIAL LIGHTING INTEGRATION ON BUILDING OCCUPANTS’ HEALTH AND PERFORMANCE

EFFECTIVENESS OF SUBTERRANEAN HEAT USE IN AN EARTH TUBE COMMUNITY HOUSE

107

EFFICACY OF DOUBLE SKIN FAÇADE ON ENERGY CONSUMPTION IN OFFICE BUILDINGS IN PHNOM PENH CITY

119

A STUDY OF BUILDING RENOVATION TO BE A NET ZERO ENERGY BUILDING: CASE STUDY OF ENERGY MANAGEMENT AND INNOVATION OFFICE, BUILDING AND FACILITY DIVISION, KHON KAEN UNIVERSITY

133

Contacts & Offices: Professor Dr. Ahmad Sanusi Hassan (Editor-in-Chief), School of Housing, Building and Planning, UNIVERSITI SAINS MALAYSIA, 11800 Minden, Penang, MALAYSIA. Tel: +60-4-653-2835 Fax: +60-4-657 6523, Sanusi@usm.my Editor@TuEngr.com Associate Professor Dr. Boonsap Witchayangkoon (Executive Editor), Faculty of Engineering, THAMMASAT UNIVERSITY, Klong-Luang, Pathumtani, 12120, THAILAND. Tel: +66-2-5643005 Ext 3101. Fax: +66-2-5643022 DrBoonsap@gmail.com Postal Paid in MALAYSIA/THAILAND.

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies http://TuEngr.com

AN INVESTIGATION AND TEST OF NATURAL RUBBER LATEX SOIL CEMENT ROAD a

Kanchana Pinwiset , Winai Raksuntorn

, and Boonsap Witchayangkoon

Department of Civil Engineering, Faculty of Engineering, Thammasat University, Rangsit, Pathumtani, 12120 THAILAND

ARTICLEINFO

Article history: Received 02 February 2018 Received in revised form 14 March 2018 Accepted 20 March 2018 Available online 23 March 2018

Keywords: NR; NRL; Red dirt soil; Trial Mix Cement; unconfined compression test; surfactant.

ABSTRACT

This research applies natural rubber latex (NRL) to improve the quality of cement clay roads. In laboratory test, multiple specimens have been prepared. The research uses high ammonia latex concentrate (60% Dry Rubber Content (DRC)), mixed with surfactant and pure water. Then it was sprayed and mixed to the red dirt road that has been admixed with cement. The red dirt material used for the research was taken from Ubon Ratchathani province, northeastern of Thailand. The dirt soil is a mix of gravel, sand, and clay with poorly graded grain size distribution. The test uses varying amount of cement (4%, 6% and 8%), and NRL (0%, 5%, 8%, 10%). From the experiment, the best mixture ratio is to use NRL 5%, cement 8%, and surfactant 2%. With seven-day air-curing, the averaged compressive strength of the rubber latex soil cement specimens was 1.72 MPa. © 2018 INT TRANS J ENG MANAG SCI TECH.

1. Introduction Thailand, the world major exporters of rubber latex, is likely to produce rubber latex even more. The global natural rubber latex (NRL) prices had once been surged. Over supplies, plunging NRL prices (one-fifth of their peak) have driven more than six million natural-rubber Thai growers into a corner (Kotani, 2016). The Royal Thai Government has issued a national policy regarding this matter to increase the uses of NRL.

One of rescue programs is to use NRL in the

road constructions, such as asphaltic concrete roads.

However, the use of NRL required

complicated process with typical mixture machinery. It is learned that asphaltic concrete roads have longer product life with lesser maintenance. Nevertheless, the amount use of NRL is rather limited. Thus this research attempts to apply NRL to the red dirt roads, as they are many thousands of such roads in Thailand.

These red dirt roads are used for transporting agricultural

*Corresponding authors (W.Raksuntorn and B.Witchayangkoon). Tel: +66-2-564-3005 E-mail: drboonsap@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/067.pdf.

products to markets.

After using for a short period, these become rough and corrugated red dirt

roads, probable with soil settlements and cracks.

Frequent yearly maintenances are needed to

maintain the roads in usable and comfortable conditions, needing huge amount of budgets. To these dilemmas, this work studies and applies NRL as an additive to soil cement road, to better serves the road users.

2. Literature Review Many decades ago, Fernando and Nadarajah (1969) applied natural rubber latex in road construction in Malaysia.

Nrachai et al. (2005) and Nopparat et al. (2012) studied on the

modification of asphalt cement by NRL for pavement construction. Shafie et al. (2013) reported the effect of blending interaction on physical properties of natural rubber latex (NRL) modified asphalt binder. Later, Shaffie et al. (2015) applied natural rubber latex polymer modified binder (NRMB) to study stripping performance and volumetric properties evaluation of hot mix asphalt (HMA) mix design. Chowdhury et al (2017) reported the effect of natural rubber and zycotherm on moisture performance of asphalt mixtures. It found that natural rubber and warm additives can mitigate moisture damage of dense-graded asphalt mixtures. An overview on natural rubber application for asphalt modification has been summarized and reported (Azahar et al., 2016). Lukjan et al. (2017) investigated the use of recycled low density polyethylene (LDPE) plastic and NRL as polymer additives in asphaltic concrete pavement. The result showed that adding 2.5% LDPE and 2.5% NRL by mass of optimum binder content (4.90%) can enhance both the volumetric and mechanical properties of the mixture with better durability, rutting resistance, and stiffness than conventional asphalt concrete. All the works have been done and reported so far from researchers involve with adding NRL to enhance asphaltic pavements. No work has been on using NRL to soil cement road which this work is about.

3. Study Method 3.1 Preparation of Materials Red dirt soil in this study is obtained from Amphoe Trakan Phuet Phon (15°36′44″N 105°1′19″E), Ubon Ratchathani Province, Thailand. The main reason is the abundance of red dirt soil in the area.

Portland cement type 1 is employed in this study, which is used for general

constructions. Natural rubber latex (NRL) liquid should have high ammonia latex concentration (60% Dry Rubber Content (DRC)). water is prepared. 68

Surfactant is available from the market.

Figure 1 exhibits all materials used in this study.

Kanchana Pinwiset, Winai Raksuntorn, and Boonsap Witchayangkoon

A gallon of clean

Figure 1: Materials used in this study.

3.2 Testing 3.2.1 Testing of Red Dirt Soil To learn characteristics of material, Trakan Phuet Phon red dirt soil is tested for Liquid Limit, Plastic Limit (ASTM D4318), Sieve Analysis, Coarse Aggregates (ASTM C136/C136M), Modified Compaction Test (ASTM D1557), and Unconfined Compressive Strength (ASTM D2166 / 2166M). 3.2.2 Trial Mix Cement and NRL The test varies amount of Portland cement and NRL.

This study has 12 trial batch

demonstrations, with 2% surfactant. Detail of trial batch demonstrations is given in Table 1: Compressive strength of molded soil-cement cylinders is determined according to ASTM D1633. Table 1: Detail of trial batch demonstrations of trial mix cement and NRL. Trial Batch # 1 2 3 4 5 6 7 8 9 10 11 12

% cement 4

% NRL liquid 0 5 8 10 0 5 8 10 0 5 8 10

surfactant

Each trial batch demonstration uses red dirt soil 2500grams. Red dirt soil is dry mixed with cement, according to Table 1. Then water and surfactant is added to the mix, followed by NRL, as demonstrated in Figure 2. *Corresponding authors (W.Raksuntorn and B.Witchayangkoon). Tel: +66-2-564-3005 E-mail: drboonsap@gmail.com. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/067.pdf.

Figure 2: A trial batch demonstration showing a mix together of soil, cement, water, surfactant and NRL liquid.

For modified compaction test (ASTM D1557), the mixture from each trial batch demonstration is placed into a mold, total five layers (about 500grams each).

Each layer is compacted following

ASTM D1557, to finally get a specimen. The process repeated to get total three specimens for each trial batch class. All trial batch demonstration specimens are placed in plastic bags in order to prevent moisture change, see Figure 3.

After seven-day curing, specimens are soaked in water

for two hours, and then dried in room temperature.

Unconfined compression test (ASTM D2166 /

2166M) is then executed, see Figure 4.

Figure 3: trial batch demonstration specimens and curing

Figure 4: Unconfined compression test.

Kanchana Pinwiset, Winai Raksuntorn, and Boonsap Witchayangkoon

3.2.3 Friction Test To find anti-slip of natural rubber latex soil cement, the friction test is executed according to AASHTO T279-96. The Portable Skid Resistance Tester (British Pendulum Tester (BPT)) is used, see Figure 5.

Figure 5: Portable Skid Resistance Tester (British Pendulum Tester (BPT) of a trial batch demonstration specimen from the mix of natural rubber latex soil cement

4. Test Results From laboratory experiment of the three samples of red dirt soil supplied from Ubon Ratchathani Province of Thailand, Table 2 gives test result detail in terms of geotechnical engineering properties. Table 2: Test result of red dirt soil samples.

Properties Liquid Limit, LL (%) Plastic Limit, PL (%) Plasticity Index, PI (%) % Finer 2" % Finer 1"

% Finer 3/8" % Finer No. 4 % Finer No. 10 % Finer No. 40 % Finer No. 200 Percentage of Wear (%) Maximum Dry Density (t/m3)

Optimum Water Content (%)

Sample#1 25.1 14.8 10.3 100.0 100.0

Sample#2 24.7 14.9 9.8 100.0 95.4

Sample#3 24.8 14.8 10.1 100.0 99.5

Average 24.9 14.8 10.1 100.0 98.3

80.2

70.4

76.4

75.7

54.9 42.4 37.5 20.5 32.8

45.7 34.6 30.7 16.6 35

49.2 36.4 32.8 18.3 34.4

49.9 37.8 33.6 18.5 34.1

2.1

2.2

2.1

12.1

11.7

9.5

11.1

*Corresponding authors (W.Raksuntorn and B.Witchayangkoon). Tel: +66-2-564-3005 E-mail: drboonsap@gmail.com. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/067.pdf.

When consider values of test result in Table 2, the source material red dirt soil supplied from Ubon Ratchathani Province of Thailand is poorly graded grain size distribution. abrasion test, percentage of wear is rather medium.

Los Angeles

In overall, the test result is acceptable.

After seven-day air-curing, specimens from all trial batches are tested for compressive strength (đ?&#x2018;&#x17E;đ?&#x2018;&#x17E;đ?&#x2018;˘đ?&#x2018;˘ ) according to standard for unconfined compression test ASTM D2166 / 2166M. Having three specimens of each trial batch, Table 3 shows the average compressive test results.

Table 3: Compressive strength (đ?&#x2018;&#x17E;đ?&#x2018;&#x17E;đ?&#x2018;˘đ?&#x2018;˘ ) of molded soil-cement cylinders mixed with NRL Trial Surfactant % cement Batch # 1 2 4 3 4 5 6 2% 6 7 8 9 10* 8 11 12

NRL (%) 0 5 8 10 0 5 8 10 0 5 8 10

Max. dry density Avg. đ?&#x2018;&#x17E;đ?&#x2018;&#x17E;đ?&#x2018;˘đ?&#x2018;˘ (age 7 (t/m3) days) (MPa) 2.22 1.50 2.21 0.85 2.26 1.54 2.28 1.64 2.21 1.38 2.23 1.14 2.23 1.33 2.24 1.50 2.28 1.82 2.24 2.11 2.22 2.04 2.22 2.16

Note: Trial batch #10 is considered the worthiest mix.

For friction test (AASHTO T279-96) using the Portable Skid Resistance Tester (British Pendulum Tester (BPT) of three specimens with mixture according to Trial Batch#10, it finds that British pendulum numbers (BPN) are 70-77.

These numbers are high, thus giving excellent

anti-slip to the road users.

5. Discussion Table 3 shows averaged compressive strengths (đ?&#x2018;&#x17E;đ?&#x2018;&#x17E;đ?&#x2018;˘đ?&#x2018;˘ ) of molded soil-cement cylinders mixed

with NRL at different amounts.

It can be observed that adding NRL does not necessary increase

strength of specimens. This is particular true for 4% and 6% of cement added to the mix. However, when 8% cement is used, soil cement specimen strength seems to better develop. As obviously seen in Table 3, the Trial batches #10, #11 and #12 draw the attention due to rising strengths when adding NRL to the mix.

Trial batch #10, using 5% NRL, is considered the

worthiest, as compressive strengths are developed closing to Trial batch #12 which use 10% NRL. During the mix of materials used in this, it should be aware that NRL when mixing with water will be clumped and become more harden. When mixing surfactant with water and adding NRL liquid, it should be used up in two hours before it clumping together. It should be aware that dirt material obtained from different region will have different soil engineering properties. 72

Before using, a laboratory testing should be performed.

Kanchana Pinwiset, Winai Raksuntorn, and Boonsap Witchayangkoon

6. Conclusion This study utilizes NRL liquid to improve strengths of red dirt soil cement roads. material is originated from Ubon Ratchathani province, northeastern of Thailand.

The red dirt Even the dirt

soil, a mix of gravel, sand, and clay, has poorly graded grain size distribution, test result is acceptable. The NRL has high ammonia latex concentrate (60% Dry Rubber Content (DRC)), mixed with surfactant and pure water. Then it was sprayed and mixed to the red dirt soil that has been admixed with cement. From the compressive strength experiment, the worthiest mixture ratio is to use NRL 5%, cement 8%, surfactant 2%.

7. References ASTM C136 / C136M. Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. (ASTM Volume 04.02 Concrete and Aggregates). ASTM D1557. Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort. (ASTM Volume 04.08 Soil and Rock (I): D421 – D5876) ASTM D1633. Standard Test Methods for Compressive Strength of Molded Soil-Cement Cylinders. (ASTM Volume 04.08 Soil and Rock (I): D421 – D5876) ASTM D2166 / D2166M. Standard Test Method for Unconfined Compressive Strength of Cohesive Soil (ASTM Volume 04.08 Soil and Rock (I): D421 – D5876). ASTM D4318 - 17e1. Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils. (ASTM Volume 04.08 Soil and Rock (I): D421 – D5876). Azahar, N.F.B.M., Hassan, N.B.A., Jaya, R.P., Kadir, M.A.B.A., Yunus, N.Z.B.M. and Mahmud, M.Z.H., 2016. An overview on natural rubber application for asphalt modification. Int J Agric For Plant, 2, p.212. Fernando, M.J. and Nadarajah, M. 1969. Rubber Res Inst Malaya Journal.

Use of natural rubber latex in road construction.

Kotani, Hiroshi. 2016. Plunging prices drive world's biggest producer out of business. Nikkei Asian Review. http://asia.nikkei.com/Business/Plunging-prices-drive-world-s-biggest-producer-out-of-business Nopparat, V., Jaratsri, P., Nuchanat, N. 2012. Modification of asphalt cement by natural rubber for pavement construction, Rubber Thai J. 1, 32–39. Nrachai, T., Chayatan, P., and Direk, L. 2005. The modification of asphalt with natural rubber latex. Proc. Eastern Asia Soc. Transp. Stud. 5, 679–694. Shafie, E., Ahmad, HJ., Arshad, K., Kamarun, D., and Shafie, A. 2013. Effect of blending interaction on physical properties of natural rubber latex (NRL) modified asphalt binder, National Postgraduate Seminar, Universiti Teknologi MARA, Shah Alam, Malaysia. Shaffie, E., Ahmad, J., Arshad, A.K., Kamarun, D. and Kamaruddin, F., 2015. Stripping performance and volumetric properties evaluation of hot mix asphalt (HMA) mix design using natural rubber latex polymer modified binder (NRMB). In InCIEC 2014 (pp. 873-884). Springer, Singapore. Chowdhury, P.S., Kumar, S. and Sarkar, D., 2017. Effect of Natural Rubber and Zycotherm on *Corresponding authors (W.Raksuntorn and B.Witchayangkoon). Tel: +66-2-564-3005 E-mail: drboonsap@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/067.pdf.

Moisture Performance of Asphalt Mixtures. 71st RILEM Annual Week & ICACMS 2017, Chennai, India, 3â&#x20AC;&#x201C; 8 September. Lukjan, A., Phoonnual, A., Laksanakit, C. and Jaritngam, S., 2017. Utilization of Recycled Plastic and Natural Rubber in Asphalt Concrete to Improve Performance of Flexible Pavement. Suranaree Journal of Science & Technology, 24(4).

Kanchana Pinwiset is a graduate student in Department of Civil Engineering, Faculty of Engineering, Thammasat University, Thailand. She earned her Bachelor of Engineering (Civil Engineering) degree from Thammasat University. Her research involves experiments of red dirt soil roads, in particular for agricultural purposes.

Dr. Winai Raksuntorn received his PhD (Civil Engineering) from University of Colorado, USA. He is currently an Assistant Professor in the Department of Civil Engineering, Faculty of Engineering, Thammasat University. His research interests include transportation safety analysis, traffic operations and management, traffic impact studies, traffic flow modeling, highway capacity analysis, advanced traffic management for intelligent transportation systems. Dr. Boonsap Witchayangkoon is an Associate Professor in Department of Civil Engineering at Thammasat University. He received his B.Eng. from King Mongkutâ&#x20AC;&#x2122;s University of Technology Thonburi with Honors. He continued his PhD study at University of Maine, USA, where he obtained his PhD in Spatial Information Science & Engineering. Dr. Witchayangkoon current interests involve applications of multidisciplinary and emerging technologies to engineering.

Kanchana Pinwiset, Winai Raksuntorn, and Boonsap Witchayangkoon

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies http://TuEngr.com

BEHAVIORS OF THE COMPOSITE SLAB COMPOSED OF CORRUGATED STEEL SHEET AND CONCRETE TOPPING USING NONLINEAR FINITE ELEMENT ANALYSIS a

Arak Montha , Sayan Sirimontree

, and Boonsap Witchayangkoon

Department of Civil Engineering, Faculty of Engineering, Thammasat University, Rangsit, Pathumtani, 12120 THAILAND

ARTICLEINFO

Article history: Received 24 January 2018 Received in revised form 19 March 2018 Accepted 23 March 2018 Available online 26 March 2018

Keywords: Shear connector; longitudinal steel reinforcement; Composite slab section; ABAQUS; Slab deck; Concrete topping.

ABSTRACT

Behaviors under static loading of the composite slab composed of corrugated steel and concrete topping are studied in this work using Nonlinear Finite Element Analysis. The main parameters are mechanical shear connector, concrete strength, thickness of corrugated steel and additional steel rebar placed on the bottom of concrete topping. The software ABACUS® is utilized in the analysis. The analytical results are compared and calibrated to the experimental results performed by previous researchers. The verified finite element model is used to study the effects of the principle parameters, which cannot be practically performed by the experiment. The results show that slab without shear connecter failed in the brittle manner due to interface slip of concrete and corrugated steel after flexural cracking of concrete topping. The horizontal shear connectors used to prevent the interface slip are significantly increasing the load carrying capacity of composite slab. This is because concrete topping and corrugated steel are perform composite action. However, the low thickness and cross sectional area of corrugated steel, lead to the low flexural and load carrying capacity of the composite slab. It can be said that corrugated steel acts as a form of concrete topping. The most effective method to increase the flexural capacity of composite slab is by adding reinforcing bar at the bottom of concrete topping and shear connectors. The additional reinforcing bar can delay the abrupt failure of the composite slab after flexural cracking of concrete topping. © 2018 INT TRANS J ENG MANAG SCI TECH.

1. INTRODUCTION Composite slab comprises of corrugated steel sheet and structural concrete topping is an optimum flooring system commonly used nowadays for the construction of buildings. *Corresponding authors (S. Sirimontree). Tel: +66-2-564-3005 E-mail: ssayan@engr.tu.ac.th. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/075.pdf.

This

reduces the construction time and reduces the weight of the building, thus saving the cost of columns, foundations and overall construction. Laboratory tests reveal the actual behavior of the test specimens, but the interesting variables are limited and take a lot of time and resources. Finite element method (FEM) has been developed to analyze the behavior of test samples which reducing the cost, number of tests and time consuming. The finite element model verified by test results can be applied to analyze various problems which cannot be practically performed by the experiment. Nonlinear finite element models are developed to study behaviors of the composite slab composed of corrugated steel sheet and concrete topping.

The key parameters are mechanical shear

connector, concrete strength, thickness of corrugated steel and additional steel rebar placed on the bottom of concrete topping. The software ABACUS速 is utilized in the analysis.

2. LITERATURE REVIEW Sayed-Ahmed (2001) observed behavior of steel and (or) composite girders with corrugated steel webs, i.e. corrugated steel plates as webs and reinforced/prestressed concrete slabs as flanges for plate or box girders. The corrugated web increases the shear capacity. Purse (1999) applied sheet metal pan or decking and sheet metal z-shaped closures sitting upon low profile open web steel joist providing a non-structural or structural concrete brake above the walls forming vibration damping and sound & fire barriers. The z-shaped closures have apertures formed through them which correspond to the end profiles of the joist shoes of the joists, and are fitted onto the joists before or after the joists are in place. Anju (2015) studied behaviors of composite beam with shear connectors by 3D finite element modeling using ANSYS速 software. The different types of shear connectors, stud, channel, tee, and perfobond connectors were the interesting parameters. The results revealed that the channel type shear connector has less displacement compared to the other types and the perfobond type connector shows maximum displacement for the given load. Sundararooban (2017) used 3D finite element model utilized by ABAQUS速 software to analyze the behavior of the composite slab under static load. Materials model, concrete damaged plasticity and elastic-perfectly plastic, are used for concrete and steel.

The steel section was

modelled using the shell element, S4R which is a 4-nodes doubly curved thin shell element that can be reduced the integration. C3D8R was a 8-node linear brick 3D solid element used in model of concrete.

T3D2 was a 2-node linear 3D truss element used in model of steel rebar.

Effects of

sheet thickness and grade of concrete were used as the parameters. The results shown that the increase in thickness of steel deck sheet and characteristic compressive strength of concrete increased the load and moment carrying capacity of the slab. Xinpei Liu (2015) analyzed the behavior of composite beams with shear connectors by finite element method and 3D modeling with ABAQUS速 software. This model used the concrete 76

Arak Montha, Sayan Sirimontree, and Boonsap Witchayangkoon

damaged plasticity model and C3D8R element to simulate concrete and T3D2 elements to simulate reinforcing steel. The model was compared with results of Marshall et al.

Considering the

results from the finite element were consistent with experiment. Finite element can be efficiently used to analyze composite beams. From all previous studies, little information has been found regarding corrugated steel sheet and concrete composite in both experiment and analytical data.

This work applies nonlinear finite

element model to analyze flexural behaviors of corrugated steel sheet and concrete composite. The results are verified with experimental result performed by Na-Lampoon (2016). The verified model is used in parametric study.

3. THEORETICAL BACKGROUND 3.1 MATERIALS MODEL OF CONCRETE AND STEEL The tensile behavior of concrete in terms of stress-strain relationship proposed by Wahalathantri (2011) as shown in Figure 1 is used in this work.

Figure 1: Tension Stiffening Model for Abaqus by Wahalathantri (2011).

Figure 2: Compressive Stress-Strain Relationship for ABAQUSÂŽ by Hsu and Hsu (1994)

The stress - strain relationship of concrete in compression proposed by Hsu and Hsu (1994) is used and shown in Figure 2. This model can apply for concrete strength up to 62 MPa. Concrete behaves elastic for stress about 50% of ultimate compressive strength and then behave inelastic as shown in Figure3 that can be calculated by Equation (1) đ?&#x153;&#x20AC;đ?&#x153;&#x20AC; đ?&#x203A;˝đ?&#x203A;˝ ďż˝ đ?&#x2018;?đ?&#x2018;? ďż˝ đ?&#x153;&#x20AC;đ?&#x153;&#x20AC;0 đ?&#x153;&#x17D;đ?&#x153;&#x17D;đ?&#x2018;?đ?&#x2018;? = ( )đ?&#x153;&#x17D;đ?&#x153;&#x17D; đ?&#x153;&#x20AC;đ?&#x153;&#x20AC; đ?&#x203A;˝đ?&#x203A;˝ đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;? đ?&#x203A;˝đ?&#x203A;˝ â&#x2C6;&#x2019; 1 + ďż˝ đ?&#x2018;?đ?&#x2018;? ďż˝ đ?&#x153;&#x20AC;đ?&#x153;&#x20AC;0 with parameters: 1 đ?&#x203A;˝đ?&#x203A;˝ = 1 â&#x2C6;&#x2019; [đ?&#x153;&#x17D;đ?&#x153;&#x17D;đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;? /(đ?&#x153;&#x20AC;đ?&#x153;&#x20AC;0 đ??¸đ??¸0 )

đ?&#x153;&#x20AC;đ?&#x153;&#x20AC;0 = 8.9 Ă&#x2014; 10â&#x2C6;&#x2019;5 đ?&#x153;&#x17D;đ?&#x153;&#x17D;đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;? + 2.114 Ă&#x2014; 10â&#x2C6;&#x2019;3 *Corresponding authors (S. Sirimontree). Tel: +66-2-564-3005 E-mail: ssayan@engr.tu.ac.th. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/075.pdf.

(1),

(2), (3), 77

đ??¸đ??¸0 = 1.2431 Ă&#x2014; 102 đ?&#x153;&#x17D;đ?&#x153;&#x17D;đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;? + 3.28312 Ă&#x2014; 103

(4).

Where Ď&#x192;c refers to compressive stress, Îľ c refers to compressive strain, Ď&#x192;cu refers to ultimate compressive stress. Note: stress in the above equations is in kip/in2 (1Mpa = 0.145037743 kip/in2). The stress-strain relationship of steel is assumed to be elastic-perfectly plastic without strain hardening as is shown in Figure 3.

Figure 3: Elastic-perfectly plastic model of steel.

3.2 ELEMENT TYPE USED IN MODELING The concrete slab was modeled with 8-node linear brick, reduced integration elements C3D8R while the corrugated steel sheet was modeled with 4-node doubly curved general purpose shell, elements S4R. T3D2 element is used to simulate reinforcing steel. All elements used are shown in Figure 4.

(a) 8-node solid element (C3D8R) for concrete

(b) Truss element (T3D2) elements for reinforcing steel

Arak Montha, Sayan Sirimontree, and Boonsap Witchayangkoon

4. FINITE ELEMENTS SIMULATIONS This research uses the test samples of the composite slab that Tanatapong 2016 has performed. SN specimen is composite slabs composed of corrugated steel sheet with the dimension of 4000 mm (length) x 914 mm (width) x 76 mm (depth) overlaid by 125mm. thick

concrete topping

without shear connector and longitudinal steel rebar in concrete as shown in figure 5. The supports for the composite slabs are located 150 mm away from the span ends and test in the form of third point bending test. SSR specimen has the same configuration as the SN but L-bar shear connector and longitudinal steel rebar are added shown in Figure 6. Finite element model of SN and SSR are shown in Figures 7 and 8. SS specimen has the same configuration as the SN but only L-bar shear connectors are added without longitudinal steel rebar. Interface between steel and concrete is modeled by using contact properties, hard contact for normal behavior and penalty friction for tangential behavior.

Figure 5: Details specimen SN of test performed by (Na-Lampoon, 2016)

Figure 6: Finite element mesh of SN

*Corresponding authors (S. Sirimontree). Tel: +66-2-564-3005 E-mail: ssayan@engr.tu.ac.th. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/075.pdf.

Figure 7: Details specimen SSR of test performed by (Na-Lampoon, 2016)

Figure 8: Finite element mesh of SSR The material properties of concrete, steel rebar and corrugated steel sheet was referred to the results tested by Na-Lampoon (2016) as shown in Tables 1 and 2. Table 1: Concrete properties.

Concrete Ultimate strength Young’s modulus Poisson’s ratio Dilation angle Eccentricity Compression plastic strain ratio Invariant stress ratio Viscosity

28 MPa 26,365 MPa 0.2 31 0.1 1.16 0.667 0

Table 2: Properties of corrugated steel sheet , rebar and L-bar steel. Yield Strength of Steelsheet Yield Strength of RB9 Yield Strength of L-bar steel Poisson’s ratio Young’s modulus

336 MPa 436 MPa 240 MPa 0.3 210,000 MPa

Note: RB9 is round bar with 9mm diameter.

Arak Montha, Sayan Sirimontree, and Boonsap Witchayangkoon

4.1 BOUNDARY CONDITION The boundary conditions and prescribed transverse displacements of the composite slab are illustrated in Figure 9. The maximum out-of-plane deformation was applied along the depth of the slab with a linear prescribed displacement Uy to simulate the bending deformation of the composite associated with two-point loading. At the base of the corrugated steel sheet, for the left-end roller support two displacement degrees of freedom (Ux and Uy) were restrained, and for the right-end pin support three all of the three displacement degrees of freedom (Ux, Uy, Uz) were restrained.

Figure 9: Boundary conditions of the slab

5. RESULT AND DISCUSSION The FEM analytical results of the composite slab using ABAQUSÂŽ software shown an effect of mesh size or amount of the element on behavior under static loading of SN, SS and SSR are shown in Figure 10. Convergence of the solution is found to be 112,466, 60,000 and 65,996 elements for SN, SS and SSR respectively. Composite slab SN

Composite slab SS

Composite slab SSR

Figure 10: Mesh sensitivity on behavior under static loading of SN. *Corresponding authors (S. Sirimontree). Tel: +66-2-564-3005 E-mail: ssayan@engr.tu.ac.th. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/075.pdf.

The relationship between load and mid span deflection of the composite slab SN, SS and SSR compare with experimental results are shown in Figure 11. The convergence analytical results are found to be good correlation with experimental result in both linear and nonlinear range. Strength and deformation of the slab can be predicted accurately by nonlinear finite element model. It can be said that this model is reliable and can be used to perform a parametric study to consider the other involving parameters on the behaviors of composite slab. Composite slab SN

Composite slab SS

Composite slab SSR

Figure 11: Comparisons of test and analytical results of composite slabs. Analytical results

Figure 12: Test and analytical results of composite slabs.

Considering the experimental and analytical results in Figure 12, it is found that composite slab composed of corrugated steel sheet and concrete topping without shear connector (SN) can carry low load and fail in brittle mode due to the slip of the interface of steel and concrete. This is because after the flexural crack of concrete topping applied load is redistributed to corrugate steel sheet which cannot support the increasing load due to the low thickness, 0.75mm, and area of the corrugated steel sheet. Composite action of slab SN cannot be performed. acts as the form of concrete topping slab in this case. 82

Corrugated steel sheet

Providing L shape steel shear connector can

Arak Montha, Sayan Sirimontree, and Boonsap Witchayangkoon

significantly improve stiffness and load carrying capacity of the composite slab (SS). This can be said that composite action can be performed in SS slab.

Strength, stiffness and ductility can be

significantly improved in SSR slab composed of corrugated steel sheets, L shape steel shear connector and longitudinal steel reinforcement. This is due to the delay of concrete flexural cracking caused by the action of the added longitudinal steel rebar.

6. CONCLUSION The nonlinear analysis of composite slabs composed of corrugated steel sheet and concrete topping have been carried out with the Finite Element Analysis using software ABAQUS® . Elements C3D8R is used for concrete, shell element S4R for corrugated steel sheet and truss elements T3D2 for longitudinal reinforcement.

Materials model proposed by Wahalathantri

(2011) and Hsu and Hsu (1994) are used for concrete in tension and compression respectively. The interface between steel and concrete is modeled by using contact properties, hard contact for normal behavior and penalty friction for tangential behavior gives satisfactory results. The results from finite element analysis of SN, SS and SSR provide consistent solutions with the results of laboratory tests. Finite element methods using ABAQUS® can be reliably used to analysis the behavior of composite slab. Shear connector and longitudinal steel reinforcement should be provided on corrugated steel sheet before poring of concrete topping to give the most efficient composite action, stiffness, strength and ductility of composite slab.

7. REFERENCES ABAQUS® User’s Manual (2008). ABAQUS Inc. Pawtucket. Rhode Island. USA. Anju. Ta, and Smitha, K .Kb. (2016). Finite Element Analysis of Composite Beam with Shear Connectors, International Conference on Emerging Trends in Engineering, Science and Technology (ICETEST- 2015), Procedia Technology 24, 179 – 187. Hicks, Stephen. (1994). Composite slabs, EN 1994 - Eurocode 4: Design of composite steel and concrete structures. Hsu, L.S., & Hsu, C.-T.T. (1994). Complete stress-strain behavior of high-strength concrete under compression. Magazine of Concrete Research, 46(169), 301-312. Liu, Xinpei. (2016). Finite element modelling of steel-concrete composite beams with high-strength friction-grip bolt shear connectors, Finite Elements in Analysis and Design: Volume 108 Issue C, January. Luo, F., Gholamhoseini, A. and MacRae, G. A. (2015). Analytical Study of Seismic Behaviour of Composite Slabs, Steel Innovations Conference 2015 Auckland, New Zealand, 3-4 September. Na-Lampoon, T. (2016). Behaviors of Concrete-Steel Deck Composite Slab Under Static Loading. Master Thesis, Faculty of Engineering, Thammasat University, Thailand Purse, J. A. (1999). U.S. Patent No. 5,941,035. Washington, DC: U.S. Patent and Trademark Office. *Corresponding authors (S. Sirimontree). Tel: +66-2-564-3005 E-mail: ssayan@engr.tu.ac.th. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/075.pdf.

Sayed-Ahmed, E. Y. (2001). Behaviour of steel and (or) composite girders with corrugated steel webs. Canadian Journal of Civil Engineering, 28(4), 656-672. Schuster, R. M. (1970). Strength and Behavior of Cold-Rolled Steel-Deck-Reinforced Concrete Floor Slabs (Doctoral dissertation, Iowa State University of Science and Technology, Structural Engineering, 1970). Iowa: Digital Repository @ Iowa State University. Sundararooban, S.R, Krishnan, P.A. (2017). Finite Element Modelling of the behavior of Profiled Composite Deck Slab subjected, International Journal of Advanced Research in Basic Engineering Sciences and Technology (IJARBEST) Vol.3, Special Issue.24, March. Wahalathantri, B. Thambiratnam, D. Chan, T. and Fawzia, (2011). A material model for flexural crack simulation in reinforced concrete elements using ABAQUS. Proceedings of the First International Conference on Engineering. Designing and Developing the Built Environment for Sustainable Wellbeing, pp. 260–264.

Arak Montha earned his Bachelor of Engineering (Civil Engineering) degree from Thammasat University. He is a graduate student in Department of Civil Engineering, Faculty of Engineering, Thammasat University, Thailand. His research encompasses structural modeling of composite materials.

Dr. Sayan Sirimontree earned his bachelor degree from Khonkaen University Thailand, master degree in Structural Engineering from Chulalongkorn University Thailand and PhD in Structural Engineering from Khonkaen University Thailand. He is an Associate Professor at Thammasat University Thailand. He is interested in durability of concrete, repair and strengthening of reinforced and prestressed concrete structures. Dr. Boonsap Witchayangkoon is an Associate Professor in Department of Civil Engineering at Thammasat University. He received his B.Eng. from King Mongkut’s University of Technology Thonburi with Honors. He continued his PhD study at University of Maine, USA, where he obtained his PhD in Spatial Information Science & Engineering. Dr. Witchayangkoon current interests involve applications of multidisciplinary and emerging technologies to engineering.

Trademarks Disclaimer: All products names including trademarks™ or registered® trademarks mentioned in this article are the property of their respective owners, using for identification purposes only. Use of them does not imply any endorsement or affiliation.

Arak Montha, Sayan Sirimontree, and Boonsap Witchayangkoon

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies http://TuEngr.com

HOME OWNERSHIP IN LOW-COST HOUSES IN PENANG, MALAYSIA Abdunnaser Ali Moh Abujrad a

, and Ahmad Sanusi Hassan

School of Housing, Building & Planning, Universiti Sains Malaysia, Penang, MALAYSIA

ARTICLEINFO

Article history: Received 24 January 2018 Received in revised form 28 March 2018 Accepted 04 April 2018 Available online 06 April 2018

Keywords: Penang Household; Living conditions; Household characteristics; IBS; Industrialised Building System.

ABSTRACT

Low-cost housing has been the concern of many parties lately especially the government agencies. Housing prices are rising faster than wages around the world, many people especially the low-income groups thus turn towards low-cost housing for home ownership. This paper discusses the home ownership in low-cost housing in Penang, Malaysia, especially the importance of housing towards us, the low-cost housing concept adopted by the Malaysian government, and the low-cost housing provision done by both public and private sector in order to eliminate the housing crisis in Malaysia. Through the Malaysia Five-Year Plan, various programs are created and have been undertaken by both government bodies and private agencies to help increase home ownership amongst the low-income groups. Provision to provide greater number of low-cost housing has also led to the consideration of usage of alternative construction techniques such as the Industrialised Building Although the usage of IBS in System (IBS) by local authorities. Malaysia’s construction industry is gaining in popularity, however, it is yet to operate in full capacity. Through this paper, it is hoped that IBS can become more widely accepted especially for the provision of low-cost houses. The methodology for this study is through survey From the questionnaires, the household using questionnaires. characteristics of respondents are studied. The results highlight issues relating to low-cost housing such as the living conditions faced by the respondents. © 2018 INT TRANS J ENG MANAG SCI TECH.

1. INTRODUCTION A home is very important to us human as it can affect us physically and psychologically. Article 25 (1) of the Universal Declaration of Human Rights (1948) which was adopted by the United Nations to represent the first global expression of rights to which all human beings are inherently entitled stated that it is everyone’s right to have a proper housing. However, a report to *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/085.pdf.

the United Nations in 2005 stated there were an estimated 100 million homeless people in the world, and an additional 1.6 billion living without adequate housing. In this research, the study discusses home ownership in low-cost houses in Penang Malaysia. It gives the overview of the low-cost housing in Malaysia before discussing the result of the analysis, findings and recommendations in this study with particular references to home ownership of low-cost houses in Taman Tun Sardon, Penang.

2. LITERATURE REVIEW 2.1 LOW-COST HOUSING Low-cost housing is defined according to its selling price of RM 25,000 (US$6135) per unit or less (Second Malaysia Plan, 1971). The Ministry of Housing and Local Government has further laid down the following guidelines for this category of housing: 1. The target group consists of household with monthly incomes not exceeding RM 750. 2. The type of houses may include flats, terrace or detached houses. 3. The minimum design standard specifies a built-up area of 550 – 600 square feet, 2 bedrooms, a living room, a kitchen and a bathroom.

The ceiling price of RM 25,000, set in the 1982, has been a contentious issue for developers and consumers alike because the cost of construction for low-cost houses is typically higher than its selling price (Liang, 2011). Also, in the effort to improve the quality and range of housing and to accommodate social and cultural preferences, various states have initiated steps to include some 3-bedroom units in the low-cost schemes (Salleh and Lee, 1997). In 2002, the government has introduced the new pricing guideline for the low-cost houses in order to improve the quality of low-cost houses and simultaneously meet private developer’s argument for a review of the selling prices of these units. Table 1 summarises the new selling prices schedule. With the new selling prices of low-cost houses, it is to be expected that the design specifications be revised too. The new design specifications are summarized in Table 2. Table 1: Low-cost Housing Price Structure Based on Location and Target Groups (Source: Ministry of Housing and Local Government, 2002) House Price Per Unit RM 42,000 RM 35,000 RM 30,000 RM 25,000

Location (Land price per square meter) City Centre & Urban (RM 45 and above) Urban & sub-urban (RM 15 - RM 44) Small township & Sub-rural (RM 10 - RM 14) Rural (below RM 10)

Monthly Income of Target Group RM 1,200 – RM 1,500

Note: RM 1 (1 Malaysian ringgit) ≈ US$0.245

Abdunnaser A.M. Abujrad and Ahmad Sanusi Hassan

RM 1,000 – RM 1,350 RM 850 – RM 1,200 RM 750 – RM 1,000

Table 2: New Design Specifications of Low-cost Houses (Source: Ministry of Housing and Local Government, 2002)

Elements Floor Space Bedroom (Minimum number) Minimum area of habitable room First room Second room Third room Kitchen (Minimum area) Living and dining rooms

Bathroom and toilet Storage space and porch

Terrace Houses 48-60-meter square

Flats 45-56-meter square

11.7 m² 9.9 m² 7.2 m²

4.5 m² Provided as one combined space or separately with adequate area according to internal layout. Provided separately with minimum area of 1.8 m² each. Adequate provision for resident’s comfort

4.5 m² Provided as one combined space or separately with adequate area according to internal layout. Provided separately with minimum area of 1.8 m² each

Drying area (*) Launderette facilities

Adequate provision for resident’s convenience and comfort Adequate provision for each unit.

Note: (*) Must be provided according to the ‘Guidelines for the provision of launderette facilities in multi-storey buildings’ prepared by Local Government Department, Ministry of Housing and Local Government.

2.2 LOW-COST HOUSING IN MALAYSIA Low-cost housing in Malaysia is undertaken by both the private and public sectors (Salleh and Lee, 1997). The government’s commitment towards low-cost housing started during the First Malaysia Plan while the private sector’s involvement was mooted in the Third Malaysia Plan when the government realized the need and importance of the role of the private sector in ensuring an adequate supply of low-cost housing for the country (Salleh and Lee, 1997). Private sector’s participation has increased since the Fourth Malaysian Plan, when the government sought the co-operation of private developers in the provision of low-cost housing (Salleh and Lee, 1997). Specifically, the government has made it mandatory for developers to build at least 30 % low-cost houses in housing projects (Salleh and Lee, 1997). The private sector’s performance on low-cost housing improved drastically during the Sixth Malaysia Plan with a reported 100 % achievement of the targeted 217,000 units of low-cost housing for the period while the public agencies only manage to achieve an estimated number of 43.7 % (Salleh and Lee, 1997). Under the Seventh Malaysia Plan, the sensitivity of the government and the changing attitude of housing developers can be clearly seen in the participation of both parties in programs like the low-cost housing design competition organized to explore the possibilities for upgrading low-cost housing quality and reducing the cost of development (Salleh and Lee, 1997). Through the Seventh Malaysia Plan, a total of 859,480 units of houses were constructed by both the private and public sectors, giving it an achievement rate of 107.4 % since the total planned units were 800,000 *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/085.pdf.

numbers. In the Eighth Malaysia Plan, the numbers of targeted low-cost units to be built for the citizen of Malaysian were 232,000 units. But at the end of the period, both private and public sector managed to build a total of 200,513 units. This gives the achievement rate of 86.4 %. So far, the government of Malaysia have done a job well done in combining the effort of public and private sector to build affordability houses for its citizens. From 1990 till 2009, about 808,000 units of low-cost affordable housing were provided to support Malaysians in need with approximately 128,000 of these built during the Ninth Plan period (Tenth Malaysia Plan, 2010). Wanting to do more, in the Tenth Malaysia Plan, for urban and semi-urban areas, affordable housing programmes and clusters as well as the provision of low-cost housing will be expanded (Tenth Malaysia Plan, 2010). These public housing units will be offered to qualified individuals and families with the aim to encourage greater home ownership among the bottom 40% households (Tenth Malaysia Plan, 2010). The private sector will also be encouraged to develop more affordable medium-cost housing (Tenth Malaysia Plan, 2010).

2.3 USAGE OF INDUSTRIALISED BUILDING SYSTEM (IBS) IN LOW-COST HOUSING In a lay-manâ&#x20AC;&#x2122;s term, IBS is a construction system whereby the building is being built using pre-fabricated components. The manufacturing of these components are systematically done using machine, formworks and other forms of mechanical equipment. The building components such as wall, floor slab, beam column, staircase and so on are produced in mass production either in factory or at site according to the specification. Once completed, the components will be delivered to construction site for assembly and erection (Salahuddin, 2010). The most important characteristic of IBS is that the components are prefabricated on or off-site. Prefabrication means breaking a whole unit of building into different components such as the floors, walls, column, beams, roof, etc. and having these components separately prefabricated or manufactured in modules or standard dimensions. From these definitions, construction using IBS method is therefore different from the conventional method of construction. IBS system is known for its benefits in term of shorter construction time, less labour involved, material saving, better quality control and immunity to weather changes. IBS method shows a different approach to the construction method commonly used, hence, offering an alternative to the existing conventional construction system (Salahuddin, 2010). IBS was introduced to Malaysia during the early 1960â&#x20AC;&#x2122;s when the Ministry of Housing and Local Government of Malaysia visited several European countries and observed their housing development program (Thanoon et al, 2003). With the exchanged knowledge, the government started the first IBS project in the capital of Malaysia itself. About 22.7 acres of land along Jalan Pekeliling, Kuala Lumpur were being used to develop 7 blocks of 17 stories flat, 3000 units of low-cost flat and 40 shop lots. This project was awarded to JV Gammon & Larsen and Nielsen who used large panel precast concrete wall and plank slabs in the construction. The project was 88

Abdunnaser A.M. Abujrad and Ahmad Sanusi Hassan

completed within 27 months starting from 1966 to 1968. (CIDB, 2003; Thanoon et al., 2003) In 1965, the second housing project initiated by the government comprises of 6 blocks of 17 stories flats and 3 blocks of 18 stories flats at Jalan Rifle Range, Penang. The project was awarded to Hochtief and Chee Seng and they use the French Estoit System (CIDB, 2003). Another earliest IBS project was at this study’s sampling area, Taman Tun Sardon, Penang. The IBS pre-cast components and system used in this project was designed by the British Research Establishment for low-cost housing (Salahuddin, 2010), which was quite similar to the system used in a construction in Edmonton, North London (Salahuddin, 2010). Nonetheless, the building design was very basic but not considering the aspect of serviceability such as the local needs to have wet toilet and bathroom (Salahuddin, 2010). Many of the construction in the following years utilised precast wall panel system. One can observe that IBS was engage at first in the construction of low-cost high-rise residential building to overcome the increasing demand for housing needs (Salahuddin, 2010). However, the industrialisation of construction at the earlier stage was never sustained (Salahuddin, 2010). A number of Initial failures in some fabricated system made the industry players afraid of changing their construction method. Some of the foreign systems that were introduced during the late 60’s and 70’s were also found not suitable with the Malaysia’s climate and social practices (Salahuddin, 2010). As a result, after the year 1994, hybrid IBS application was used. Many national iconic landmarks such as the Bukit Jalil Sport Complex, Kuala Lumpur Convention Centre (KLCC), Lightweight Railway Train (LRT), KL Sentral Station, Kuala Lumpur tower, Kuala Lumpur International Airport (KLIA) as well as the Petronas Twin Towers are just some of the examples (Salahuddin, 2010). It is also included in the development and construction of the new administration city of Putrajaya and the first cyber city of Cyberjaya (Salahuddin, 2010).

3. METHODOLOGY The methodology for this research is through survey using questionnaires. The set of questionnaires are developed based on the objective of studies. This quantitative technique of research by the questionnaire-based survey is considered the first level of primary data collection for this study. There are two kinds of questions posed in the questionnaire namely open-ended questions and closed-ended questions. Open-ended questions are questions that allow respondents to answer freely on certain things while closed-ended questions are created to restrict their responses choices by forcing the respondents to answer according to the alternatives provided. The sampling area is narrowed down to the residential areas of Taman Tun Sardon and Taman Brown, both located side *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/085.pdf.

by side in the township of Gelugor. Taman Tun Sardon is a large working-class neighbourhood consisting of five-storey walk-up blocks of low-cost flats built in the 1980s. Taman Brown on the other hand consists of a mixture of low, medium and high cost houses ranging from terraces to semi-detached houses as well as some bungalows initially developed in the early 1960's to house government servants. The selection of these two as the sampling area is done by using the stratified multistage random sampling design. As we all know, Penang state is divided into five districts or daerah in Bahasa Malaysia namely the Southwest District (Daerah Barat Daya), Northeast District (Daerah Timur Laut), Northern Seberang Perai District (Daerah Seberang Perai Utara), Central Seberang Perai District (Daerah Seberang Perai Tengah) and Southern Seberang Perai District (Daerah Seberang Perai Selatan). Among these five districts, one district is selectively chosen. In this case, it is the Northeast District (Daerah Timur Laut). Next, among all the sub-districts, one of them is selectively chosen. In this case, it is the sub-district of Gelugor. Finally, among all the residential areas with low income groups in Gelugor, Taman Tun Sardon and Taman Brown are selectively chosen to be the sampling area. Due to the fact that there is a mixture of low, medium and high-cost houses in that area, but at the same time, more towards low-cost settlement, this makes it the main reason for Taman Tun Sardon and Taman Brown to be selected as the sampling area. Furthermore, both residential areas are located next to each other. As it is impossible to distribute the questionnaires to the total population in the sampling area, only a portion of 2.5 % from the total population is selected as the sample size. According to the Population and Housing Census by the department of statistics Malaysia (2010), Gelugor has a total household of 2,840 in the year 2010. From this, the targeted number of respondents is calculated to be 2,840 households multiplied by 2.5 % thus equals to 70 households. During the conduct of the survey, it adopted the method of random sampling. Random sampling is about a subset of individuals being chosen from a larger set. Each individual is chosen randomly and entirely by chance, such that each individual has the same probability of being chosen at any stage during the sampling process. For the case of this study, the individual is therefore referring to a household in the sampling area. Random sampling is an unbiased surveying technique. An unbiased random selection of individuals is important so that if a large number of samples were drawn, the average sample would accurately represent the population. However, this does not guarantee that a particular sample is a perfect representation of the population. Random sampling merely allows one to draw externally valid conclusions about the entire population based on the sample. The questionnaires were analysed by category as well as by factors using the cross-tabulation method. Analysis by category refers to the analysis of each part of the questionnaire, whereas analysis by factors refers to the analysis of each question in each part of the questionnaires. â&#x20AC;&#x2DC;Cross 90

Abdunnaser A.M. Abujrad and Ahmad Sanusi Hassan

tabulation’ or ‘cross-tabs’ is a method of analysis that combine two or more numeric variables. It is often presented in the form of a table in a matrix format and they provide the most basic picture of the interrelation between the two variables and can help find the interactions between them. After cross tabulation, the tabular data will be converted into graphic representations of bar charts or pie charts respectively in order for the questionnaires to be analysed using the frequency analysis. The results obtained will be presented in form of frequency number as well as percentages of the total respondents.

4. RESULTS AND DISCUSSION 4.1 TYPOLOGY OF CURRENT HOUSE

Figure 1: Typology of houses currently resided by respondents Figure 1 shows the distribution of houses according to their typology currently occupied by the respondents.

A majority of 54 % or 38 respondents are living in low-cost flat. Two-storey

terrace have the second most number of respondents with the figure of 14 % or 10 respondents followed by 2/3 storey semi-detached house with 13 % or 9 respondents. Next is the low-cost terrace with 10 % or 7 respondents and finally is the single storey terrace with 9 % or 6 respondents.

4.2 HOUSEHOLD INCOME

Figure 2: Household income of respondents For this study purpose, the respondent’s monthly household income refers to the sum of all *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/085.pdf.

forms of income, Figure 2. This includes any financial aid, monthly allowances and salary, side income and so on.

From Figure 3, the income level of RM 1,000 to RM 1,999 as well as RM

2,000 to RM 2,999 both has the most number of respondents. The income level of RM 4,000 to RM 5,000 has the lowest number of respondents in the study area. According to the Household Income and Basic Amenities Survey 2012 (HIS/BA 2012) done by the Department of Statistics, Malaysia, the mean monthly household income for Malaysians in year 2012 was RM 5,000, whereas, the median household income in Malaysia was RM 3,626 in 2012. Therefore, the mean was significantly higher than the median income because the value of the mean is skewed by high-income earners (Yin, 2014). The median gives a more accurate picture of what the â&#x20AC;&#x2DC;person in the middleâ&#x20AC;&#x2122; earns.

It is the value in the center of all households surveyed. This

means that 50 % of Malaysian households earned RM 3,626 and below in 2012 (Yin, 2014). To sum up, we can deduce that low-income households are those households with less than RM 3,000 per month. Referring back to Figure 3, it is found that 67 % or a total of 47 respondents in the study area are considered to be low-income households.

4.3 TYPOLOGY OF CURRENT HOUSE AGAINST HOUSEHOLD INCOME

Figure 3: Typology of houses currently resided by respondents according to their income level. Based on Figure 4.3, it shows that most of the respondents who are currently residing in low-cost flat, the majority of them come from the income level of RM 1,000 to RM 1,999. Followed by the income of groups level less than RM 1,000 and income level of RM 2,000 to RM 2,999, both have the second most number of respondents. As for the remaining of the income groups, the proportion of respondents was very few who are residing in low-cost flat or they reside in another categories of houses such as terrace or semi-D house.

4.4 HOME OWNERSHIP STATUS AGAINST TYPOLOGY OF HOUSES Figure 4 shows the home ownership status of respondents and grouping them according to the typology of their current shelter. Based on the figure, of the 47 home owners, a majority of 30 respondents are currently residing in low-cost flat. In addition, it has found that a small number of respondents who owned different categories of houses such as 2/3 storey semi-detached house, 92

Abdunnaser A.M. Abujrad and Ahmad Sanusi Hassan

low-cost terrace, and 2 storey terrace. On the other hand, few number of the respondents reside by renting a house thus the category of flats is remaining as the highest category in terms of tenancy.

Figure 4: Home ownership status according to the typology of houses.

4.5 HOUSEHOLD CHARACTERISTICS

Figure 5: Household size of respondents A household consists of related and/or unrelated persons who usually live together and make common provisions for food and other essentials of living (Department of Statistics Malaysia, 2010). Household size therefore refers to the number of person residing in a particular unit of dwelling. According to the Department of Statistics Malaysia (2010), the average household size for Penang is 3.93. Based on the Figure 5, it shows that the majority of household, which comprises of 56 % or 39 respondents, have a household size greater than 4 people. After that, the household size with 4 people comes in second with a percentage of 19 % or 13 respondents. Next, household size with 2 people and household size with 1 people stand side by side on the third place with each being 11 % that is equivalent to 8 respondents. Lastly, only 3 % or 2 respondents are having a household size of 3 people.

4.6 AFFORDABLE PRICE RANGE There are three categories that got the highest number of respondents among the pricing groups, it came as follows. First group of the pricing range less than RM 25,000 which they *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/085.pdf.

considered is affordable to them, a majority with 39 % of respondents as affordable as shown in Figure 6. Of these figures, a majority of the respondents are from the income level of RM 1,000 to RM 1,999 as followed by RM 2,000 to Rm 2,999. Based on Figure 4.6 also, the second group of the highest number of respondents is 25 % of respondents who agreed that the price range of RM 25,000 to RM 99,999 are considered affordable to them, resulted from the income level of RM 2,000 to RM 2,999 as the majority of respondents. Lastly, the third group of the highest number of respondents is14 % of respondents who considered the price range of RM 400,000 to RM 500,000 to be affordable for them since the majority of respondents came from income level of RM 3,000 to RM 3,999.

Figure 6: Pricing range that is considered affordable to prospect buyers

5. PROPOSAL FOR IBS SYSTEM Today, the use of IBS as a method of construction is growing moderately. Although there are some private companies in Malaysia who have already teamed up with foreign expert to offer pre-cast solution to the construction projects (IBS Survey, 2003), pre-cast concrete components and prefabricated reinforcement are still not commonly used in most private sector (Tan, 1997). Prefabrication is a key technology that can be used to increase building demand (Salahuddin, 2010). There are varieties of IBS technology offered in Malaysia such as formworks, precast load bearing wall panel, precast frame, precast floor and hollow core slab, sandwich, block panel and steel frame (Salahuddin, 2010). The construction costs involved are labour, material, equipment and overheads. Reduction in any of these costs would be beneficial to both owner and contractor. For IBS, the reduction of costs involves reducing man power, material costs and operating costs (Salahuddin, 2010). With the reduction of one of the contributing factors that lead to the hike of house prices, more affordable houses would be able to be built.

6. CONCLUSION Throughout the survey, 67 % of respondents in the study area are considered to be low-income households and a majority of them reside in low-cost flats. The low cost-flats which were built in the 1980s followed the old low-cost housing specifications, which is, equipped with 2 bedrooms, a Abdunnaser A.M. Abujrad and Ahmad Sanusi Hassan 94

small living room, a kitchen and a bathroom. The building design was very basic but not considering the aspect of serviceability such as the need for an additional wet toilet or bathroom as well as a dry kitchen. Although the government had made revision on the design specifications for low-cost houses such as to provide 3 bedrooms instead of 2, however it can be said that these amended specifications does not fully fulfil the needs of majority of low-income groups. Moreover, in the study area, 56% of families have household size greater than four members. So far, the government of Malaysia have done a good job in combining the effort of public and private sector to build affordable houses for its citizens. However, there is still an urgent need to build more affordable houses because of natural population growth, ever hiking of house prices and slow increase in wages. In order to achieve this, venturing into alternative construction technique is needed to improve the current conventional construction techniques. Several research papers have proven that the usage of IBS can enhance the provision of low-cost housing since IBS can save time and cost.

7. Acknowledgement The authors would like to express their appreciation for the financial support under Research University Grant by Universiti Sains Malaysia.

8. References Abujrad, Abdunnaser Ali Moh. And Hassan, Ahmad Sanusi (2014) Housing Affordability for Low-Income Group in Penang, Malaysia, International Workshop on Livable Cities 2014. CIDB (2003) Construction Industry Master Plan 2006 â&#x20AC;&#x201C; 2015, CIDB Publication, Malaysia CIDB (2003) National IBS Survey 2003, CIDB Publication, Malaysia Department of Statistics Malaysia, (2015) Quarterly Construction Statistics, First Quarter 2015 [Online], [Accessed on 30th June 2015], Available form World Wide Web: https://www.statistics.gov.my/index.php?r=column/cthemeByCat&cat=77&bul_id=bGZrYzd4VzV scnN3WTRoOEIrTWlkQT09&menu_id=OEY5SWtFSVVFVUpmUXEyaHppMVhEdz09 Department of Statistics, Malaysia. Household Income and Basic Amenities (HIS/BA) Survey Report 2007, 2009 and 2012 Department of Statistics Malaysia, (2010) Population and Housing Census 2010 Salleh, Ghani and Lee, Lik Meng (1997) Low-cost Housing in Malaysia. Utusan Publications and Distributors Sdn Bhd Hassan, Ahmad Sanusi (2002) Towards Sustainable Housing Construction in South East Asia. Journal: Agenda 21 for Sustainable construction in Developing Countries Hassan, A.S. (2001). Issues in Sustainable Development of Architecture in Malaysia, Penang: USM Press. Hassan, A.S. (2005) Konsep Rekabentuk Bandar di Semenanjung Malaysia: Kuala Lumpur dan Bandar-Bandar di Sekitarnya, Penang: USM Press. *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/085.pdf.

Maybelle Liang (May 2011), Forecasting of Low-cost Housing Demand in Johor Bahru, UTM. Salahuddin, Siti Nur Hafizeanie Bt. (2010) Factors Affecting Construction Time Performance For IBS in Malaysia Construction Industry, Master Thesis, Universiti Teknologi Malaysia. Samuel Boutruche, StĂŠphanie Bourgeois, Nadine Lyamouri-Bajja (2008) Raising Young Refugees' Voices in Europe and Beyond. Europe, p. 35 Siti Nur Hafizeanie Bt. Salahuddin (2010), Factor Affecting Construction Time Performance for IBS in Malaysia Construction Industry, UTM. Thanoon et. al. (2003), An Assessment of the Industrialised Building System in Malaysia, Proceeding on IBS Seminar, UPM, Malaysia. Trikha, D. N. (1999) Industrialised Building System: Prospects in Malaysia, Proceedings World Engineering Congress, Malaysia. Universal Declaration of Human Rights (1948) [Online], [Accessed on 7th April 2014] Available from World Wide Web: http://www.un.org/en/documents/udhr/index.shtml#a25 Yin Shao Loong (2014), Key Statistics, Institut Rakyat [Online], [Accessed on 7th April 2014] Available from World Wide Web: http://www.institutrakyat.org/wp-content/uploads/2014/11/IR-Key-Statistics-1-1-GDP-HDIIncome-Inequality.pdf 1 â&#x20AC;&#x201C; 10th Malaysia Plan.

Abdunnaser Ali Moh Abujrad is a graduate student at Universiti Sains Malaysia, Penang, Malaysia. His research encompasses schematic concepts for home ownership.

Professor Dr. Ahmad Sanusi bin Hassan teaches in Architecture Programme at the School of Housing, Building and Planning, University Sains Malaysia (USM). He obtained Bachelor and Master of Architecture from the University of Houston, Texas, USA. He was awarded a PhD degree from the University of Nottingham, United Kingdom. He was promoted to Associate Professor and later Full Professor. His research focuses on computer simulation on daylighting and thermal comforts, architectural history and theory, and housing in urban design. He is one of the nine regional writers involved in the preparation of Guideline: Agenda 21 for Sustainable Construction in Developing Countries: A Discussion Document, which was launched at The Earth/World Summit, Johannesburg in September 2002. At the university, he lectures in architecture courses related to urban design, studio, history, Computer Aided Design (CAD), and computer movie animation. He has integrated all these specialisations into his research, teaching, consultation and publications. He had designed several architectural projects such as mosque, USM guest house and a proposal for low-cost houses for fishermen community.

Note: The original work of this article was reviewed, accepted, and orally presented at the 3rd International Conference-Workshop on Sustainable Architecture and Urban Design (ICWSAUD 2017), a joint conference with the 3rd International Conference on Engineering, Innovation and Technology (ICEIT 2017), held at Royale Ballroom at the Royale Chulan Penang Hotel, Malaysia, during 13-15th November 2017.

Abdunnaser A.M. Abujrad and Ahmad Sanusi Hassan

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies http://TuEngr.com

THE IMPACT OF DAYLIGHTING-ARTIFICIAL LIGHTING INTEGRATION ON BUILDING OCCUPANTS’ HEALTH AND PERFORMANCE Najib T. Al-Ashwal a

, and Ahmad Sanusi Hassan

School of Housing, Building & Planning, Universiti Sains Malaysia, Penang, MALAYSIA

ARTICLEINFO

Article history: Received 24 January 2018 Received in revised form 28 March 2018 Accepted 09 April 2018 Available online 12 April 2018

Keywords: Building Occupants; Energy efficiency; Occupants’ productivity.

ABSTRACT

Natural lighting was the primary light source in buildings prior to the invention of the electrical lighting in 1879. After that, artificial lighting was mainly utilized to supplement natural lighting. Artificial lighting has nowadays become the major source to illuminate working spaces. However, due to the growing concern of passive design, energy efficiency and environmental issues, daylighting is integrated with artificial lighting to reduce energy consumption. The benefits obtained from the efficient utilization of daylight are not limited to architecture and energy aspects only. Rather, natural lighting affects building occupants in various aspects. This includes occupants’ preferences, health, performance, and productivity. This paper aims to review the previous literature to highlight the impact of daylighting on building occupants, particularly in schools and office buildings. Many studies have proven that a large number of students and office workers (60-85%) prefer daylighting as a source of illumination. It was found that proper daylighting designs help maintain good health, reduce stress levels of office workers and alleviate headaches. Internal lighting conditions have had a noticeable effect on building occupants’ performance and productivity. An increase of about (5-15%) in the productivity of office workers was reported when daylight was efficiently integrated with artificial lighting in their working places. The reviewed studies showed an increase in students and teachers’ attendance in classes, which were mainly illuminated by daylight. In addition, students’ progress was faster in math and reading tests (20-26%) compared with those, who occupied a classroom with less daylighting. © 2018 INT TRANS J ENG MANAG SCI TECH.

1. INTRODUCTION For many years throughout the human history, natural lighting was the only efficient source of light, and thus it was difficult to perform visual tasks during night-time or cloudy days. This *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/097.pdf.

indicates that basic lighting condition is required to do various visual tasks. Human beings, therefore, searched for alternatives to light sources other than natural lighting to fulfill the required lighting conditions. Nowadays, daylight is not the only source of light. The electric lighting fixtures were significantly developed and working hours have become longer. Before the existence of artificial lighting, it was important to properly design for daylighting. Because of the shortage of daylight in northern Europe, especially in winter, large windows and high ceilings were used to provide sufficient natural lighting into the interior space. Different window designs were found in the southern countries due to the need to minimize heat gain during summer along with providing adequate natural lighting. Studies have found that incorporating a courtyard into a building design provided acceptable solutions to provide daylight into internal spaces (Phillips, 2004). In the 20th century, architectural styles have been developed and at the same time maintaining the traditional design for daylight. However, the environmental aspects and energy conservation were not considered during the design process. Daylighting design was noticeably disregarded due to the wide use of low-cost fluorescent lamps. Many buildings were found to be poorly designed for daylighting, particularly between 1945 and 1975, when compared with historical buildings (Baker et al., 2013). Around the turn of the 20th century, awareness towards daylight designs has been increased with the great influence of remarkable architects such as Frank Lloyd Wright, le Corbusier, Louis Kahn, and Louis Sullivan. These architects tried to integrate daylighting designs with the buildingsâ&#x20AC;&#x2122; aesthetic values and functional requirements (Mazharuddin, 2000). Currently, many books, articles, and methods have been produced concerning the efficient utilization of natural light from the visual and aesthetic aspects, as well as energy efficiency views (Phillips, 2004). It has become obvious from observations based on human behaviors that working and living space arrangement and research studies indicated that natural lighting is desirable by building occupants. Windows are important in buildings not only to provide adequate natural lighting but also to maintain a connection with the outside view. The quality, variability and spectral composition are additional important factors to illuminate spaces with daylight. Building occupantsâ&#x20AC;&#x2122; reactions to indoor environments were reviewed and recorded. Occupants pointed out that natural lighting is preferred to fulfill two basic human visual needs. The first is the ability to perform a visual task and see the space well, whereas the second is to gain some environmental stimulation. People admitted that health is highly affected by the long-term working under artificial lighting. They believed that less stress and discomfort are major advantages of working in a space illuminated mainly with natural lighting (Hwang & Kim, 2011). Good conditions to perform various visual tasks can be provided by daylight as high 98

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illumination levels are delivered and excellent color rendering and discrimination are allowed. However, poor daylight designs can create reflections due to the very high luminance and discomfort glare interfering with good vision. Therefore, efficient daylight designs need to be taken into careful consideration at an early stage of the building design to get the full advantage of daylight while minimizing the problems associated with excessive daylight (Egan & Olgyay, 2002). The main objective of this paper is to highlight the impact of daylighting on building occupants, particularly with regard to health, performance, productivity, and financial effect. Therefore, this study focuses on the influence of the utilization of available daylight in office buildings and schools because these types of facilities are mostly occupied during the daytime. Accordingly, this can provide a high potential to take the natural lighting benefits and advantages along with the reduction in the energy consumption.

2. BUILDINGS OCCUPANTS’ PREFERENCES Several studies have reported that the use of daylight to illuminate the indoor space is better than artificial lighting with relation to its impact on buildings’ occupants. A study on the perceived attributes of windows was conducted in England and New Zealand using a survey questionnaire (Cuttle, 1983). Office workers responded to questions related to the importance of windows in the workplace and, if so, why windows are important for them and how. It was reported that almost all respondents (99%) prefer to have windows in their offices. At the same time, 86% of the surveyed respondents indicated that the most desirable source of light is daylight. They believe that health is highly affected by long-term working hours under artificial lighting. In addition, less stress and discomfort were found to be two major advantages of working in a space illuminated mainly with natural lighting (Cuttle, 1983). In another related study, Heerwagen et al (1998) conducted a survey in an office building in Seattle in the USA in 1984 to investigate the occupants’ reaction to daylight. The survey results indicated that more than 50% of the respondents believed that natural light is the best source of light owing to many factors such as psychological relief, visual comfort, general health, the appearance of the space, and color appearance of finishing and furniture. Respondents whose offices were not provided with windows strongly supported such views and perceptions than those with windows in their offices (Veitch & Newsham, 1998). Similar data were obtained from a study on university students in Canada to investigate their preferences, beliefs, and knowledge about space illumination (Veitch et al., 1993). The study findings revealed that beliefs and perceptions about lighting influence on health were recognized by the majority of students (65-78%). Students confirmed that natural light has, in fact, many advantages over other light sources as 52% of the surveyed students mentioned that they did their work better in places, which were mainly illuminated by daylight. *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/097.pdf.

Back in 2006, another study was conducted to investigate the subjective problems and advantages related to the use of daylighting in office buildings (Galasiu & Veitch, 2006). The results are summarized as follows: 

Office workers strongly prefer daylight in their workplaces, associated mainly with the belief that better health can be supported by the use of natural lighting.



Office workers overestimate daylight contribution to the overall illumination when both electric light and daylight are used.



In general, people prefer larger windows in their offices.

Studies have proven that both students and teachers preferred classrooms filled with daylight and attractive views to the outside, which improves the students and the teachers’ attendance and performance (Lechner, 2014).

3. THE IMPACT OF DAYLIGHTING ON BUILDING OCCUPANTS’ HEALTH Many studies indicated that building occupants’ health can be maintained by the proper use of daylight. The U.S. Department of Energy conducted a study in 2000 to investigate the effect of daylight on office workers. The study found that staff with windows near their working spaces experienced fewer symptoms related to “sick buildings” by 20% compared with windowless offices (Franta & Anstead, 1994). It was reported that the appropriate use of daylighting can reduce the occurrence of eyestrain, headaches and Seasonal Affective Disorder (SAD). SAD and headaches can happen as a result of insufficient illumination levels. Therefore, the use of proper spectral light can improve the illumination level. Nevertheless, eye strain is regarded as a major health problem, which is associated with lighting conditions. Eye strain can be reduced by implementing the proper design and integration of daylight to provide the human eye with the best light spectrum (Heerwagen et al., 1998). Another important influence of the efficient use of daylight is the improvement of office building occupants’ positive moods. This can result in lowered absenteeism, work motivation, work involvement, and can increase job satisfaction as well. It was also found that discomfort and distraction were consequences of workers’ negative moods, while their positive moods resulted in more daily activities such as social interaction among staff members and better physical setting at work (Plympton et al., 2000). A report, which was published in ‘The Management Review’ in 1999, indicated that many health problems can result from the lack of light and particularly natural light. Health problems include, for example, maladjustment of our body clock (circadian rhythms), Seasonal Affective Disorder (winter depression or winter blues) and consistent periods of reduced productivity (Singh et al., 2010). Many studies have suggested that the overall health and physical development of students and 100

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teachers in classrooms can be promoted by proper utilization of natural lighting. In Sweden, a study on students of 90 elementary schools was carried out to evaluate the students’ health, behavior, and cortisol (stress hormone) levels in four classrooms with a variation in levels of daylight over the period of one year. The results indicated that the absence or low level of daylight directly affected basic hormone pattern. Consequently, the students’ ability to concentrate or cooperate was affected and eventually resulted in a negative impact on their body growth (Nicklas & Bailey, 1995). A comparative study between students in classrooms with full spectrum light and students in classrooms with conventional lighting was conducted in elementary schools in Alberta, Canada. Fewer days of absence per year were recorded in the classrooms with natural lighting and the overall students’ health was enhanced. The findings also indicated that lower cooling load and lower capacity of heating, ventilation, and air conditioning (HVAC) system were achieved with the efficient integration of artificial lighting with daylight. This resulted in a better learning environment due to the minimization of the noise levels in both the library and classrooms (Nicklas & Bailey, 1997).

4. THE

IMPACT

DAYLIGHTING

BUILDING

OCCUPANTS’

PRODUCTIVITY Office workers hold strong beliefs on the importance of lighting conditions in their working space environment. Workers’ productivity can be negatively affected by unfavorable lighting conditions. However, it is quite challenging to accurately define productivity as a dependent variable in human performance studies. Productivity improvement takes place when people are able to perform their tasks faster, more properly, for longer periods, and without getting tired (Abdou, 1997). The results of the previous research in indoor spaces without windows vary according to the space function. In schools, an increase has been reported in students’ absenteeism and lack of interest in windowless classrooms. People, in general, strongly prefer to have windows in their working places in office buildings (Edwards & Torcellini, 2002). In 1996, renovation works were completed to improve the indoor lighting conditions’ quality in the Reno Post Office in Nevada. The renovation was accomplished by the installation of better artificial lighting fixtures and the enhancement of delivered daylight into the indoor space. The findings revealed that an increase of about 8% in productivity was recorded in the first 20 weeks in the renovated building compared with the previous year (Romm & Browning, 1994). Pennsylvania Power and Light found a drop of 25% in absenteeism rates, an increase of 13.2% in productivity and a decline of 69% in energy costs after upgrading the building to integrate more daylight than before (Franta & Anstead, 1994). In 1983, Lockheed Martin designers changed the layout of their offices in Sunnyvale, California to open offices’ layout and install a lighting control system to integrate daylighting with artificial lighting. This has successfully improved the *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/097.pdf.

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interaction among the staff and reduced levels of lighting energy consumption. An increase of about 15% in the contract productivity was recorded. This happened because of the effective integration of daylighting with artificial lighting. In the same vein, VeriFone Incorporation constructed a new Worldwide Distribution Center near Los Angeles, California with a better daylighting design. An increase of more than 5% in productivity was recorded for the first year and a half after moving to the new building in addition to an increase of 25-28% in the total product output (Edwards & Torcellini, 2002). In the early 1990s, West Bend Mutual Insurance built a new building for their employees. The constructed building was designed so that almost all spaces have windows for natural lighting with personal control over task lighting and indoor temperature. Accordingly, it was reported that productivity was increased by 2.8% as a result of the new workstations with personal control (Romm & Browning, 1994). Another study, which includes four case studies, was conducted to investigate the effectiveness of students’ performance due to daylight integration in their buildings. The results showed an increase in both students and teachers’ attendance compared with schools with traditional illumination systems. It was reported that students progressed 26% faster in reading tests and 20% faster in math tests when their classrooms were mainly illuminated with daylighting (Plympton et al., 2000). In North Carolina, test scores of students in three schools with daylight integration were compared with scores in the region school system in general and other new schools within the region. The main results revealed that students, who have a daylighting system in their schools, performed better than those in non-daylight schools (Nicklas & Bailey, 1997).

5. THE FINANCIAL EFFECT OF DAYLIGHTING INTEGRATION WITH ARTIFICIAL LIGHTING The cost of the initial construction of a building and employees’ recruitment is large compared with the cost of operation, maintenance, and energy. The implementation of daylighting does not add much cost to the construction cost, operation or maintenance. However, it significantly reduces lighting energy consumption and associated cooling load. When the work environment in West Bend Mutual Insurance building was improved, an increase in profit levels was reported due to the improved productivity. It was reported that moving some of Lockheed Martin offices to a building with daylight integration has led to an increase in productivity and consequently financial savings were obtained. It was also reported that electricity bills were reduced and lower absenteeism was achieved (Romm & Browning, 1994). The report, which was published in EPRI Journal in 1998, stated that buildings with better daylighting designs can have up to 20% higher rental income than buildings that use electric lights only. The Environmental Design and Construction (2001) mentioned that the value of a property can be significantly increased when energy-efficient building designs are incorporated. This can be attributed to lower operation and maintenance costs (Franta & Anstead, 1994). 102

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Furthermore, it was found that the improvement of daylighting in schools did not essentially result in an increase in the construction cost of the school or operation. The initial capital cost can be reduced when daylight is properly integrated using a suitable lighting control system, and improving electrical and mechanical systems due to the decrease in lighting and cooling loads. In addition, lower electrical load and less number of lighting fixtures will reduce the costs of operation and maintenance (Nicklas & Bailey, 1995).

6. CONCLUSION Great importance is placed on construction and maintenance costs when designing buildings. These buildings will be occupied by real people, and therefore, their psychological and physiological needs should be given priority. The occupants’ performance will be improved as a result of their health improvement, which benefits employers and building owners. It was concluded that natural light has a positive impact on the building occupants’ performance, productivity, and their health as well when daylighting systems are properly designed, installed and maintained. Good health can be maintained and some medical disorders can be remedied through the effective use of natural light. Natural light creates a pleasant environment, which can result in lower stress levels of office workers. The better health employees have, the higher their productivity rates will be. The financial benefits for the employers are considered as direct results of a better work productivity. In addition, the performance of students will surely be better in classrooms with natural light. Studies have shown that students scored higher in natural-lighting-illuminated classrooms compared with students in poorly daylight-designed classrooms. In addition, students’ health can be enhanced with better daylighting designs due to an increase in vitamin D intake. Students will grow stronger bones and they will have fewer dental cavities under full-spectrum lighting.

Studies have shown that indoor lighting conditions have a

strong influence on people in different environments from different aspects. Therefore, the effects of natural lighting on building occupants should be carefully considered at an early stage of the building design. Eventually, satisfaction for both building occupants and owners can be fulfilled through more efficient designs of daylighting.

7. ACKNOWLEDGEMENT The authors would like to express due appreciation and gratitude for the financial support under the Fundamental Research Grant Scheme, which is granted by the Ministry of Higher Education and Universiti Sains Malaysia (USM) in Penang, Malaysia.

8. REFERENCES Abdou, O. A. (1997). Effects of Luminous Environment on Worker Productivity in Building Spaces. Journal of Architectural Engineering, 3(3), 124–132. *Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/097.pdf.

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Baker, N. V. ., Fanchiotti, A., & Steemers, K. (2013). Daylighting in Architecture, a European Reference Book. Routledge. Cuttle, C. (1983). People and Windows in Workplaces. In Proceedings of the people and physical environment research conference (pp. 203–212). Wellington, New Zealand. Edwards, L., & Torcellini, P. (2002). A literature review of the effects of natural light on building occupants. Egan, M. D., & Olgyay, V. W. (2002). Architectural Lighting (second edi). McGrow-Hill Higher Education. Franta, G., & Anstead, K. (1994). Daylighting Offers Great Opportunities. Window \& Door Specifier-Design Lab, 40–43. Galasiu, A. D., & Veitch, J. A. (2006). Occupant preferences and satisfaction with the luminous environment and control systems in daylit offices: a literature review. Energy and Buildings, 38(7), 728–742. Heerwagen, J., Johnson, J. A., Brothers, P., Little, R., & Rosenfeld, A. (1998). Energy Effectiveness and the Ecology of Work: Links to Productivity and Well-Being. In Proceedings of the1998 ACEEE Summer Study on Energy Efficiency in Buildings. Richland, WA (US): American Council for an Energy-Efficient Economy. Hwang, T., & Kim, J. T. (2011). Effects of Indoor Lighting on Occupants’ Visual Comfort and Eye Health in a Green Building. Indoor and Built Environment, 20(1), 75–90. Lechner, N. (2014). Heating, cooling, lighting: Sustainable design methods for architects. John Wiley & Sons. Mazharuddin, S. A. (2000). Linear Atria Daylight Analysis: a Graphical Design Tool. King Fahd University of Petroleum and Minerals. Nicklas, M. H., & Bailey, G. B. (1995). Analysis of the Performance of Students in Daylit Schools. Innovative Design. Nicklas, M. H., & Bailey, G. B. (1997). Daylighting in Schools: Energy Costs Reduced…Student Performance Improved. Strategic Planning for Energy and the Environment, 17(2), 41–61. Phillips, D. (2004). Daylighting. Natural Light in Architecture. Industrial medicine & surgery (Vol. 1). Plympton, P., Conway, S., & Epstein, K. (2000). Daylighting in Schools: Improving Student Performance and Health at a Price Schools Can Afford. American Solar Energy Society Conference, (August), 10. Romm, J. J. ., & Browning, W. D. (1994). Greening the Building and the Bottom Line: Increasing Productivity Through Energy-Efficient Design. Snowmass, Colorado: Rocky Mountain Institute. Singh, A., Syal, M., Grady, S. C., & Korkmaz, S. (2010). Effects of Green Buildings on Employee Health and Productivity. American Journal of Public Health, 100(9), 1665–1668. Veitch, J. A., Hine, D. W., & Gifford, R. (1993). End Users’ Knowledge, Beliefs, and Preferences 104

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for Lighting. Journal of Interior Design, 19(2), 15–26. Veitch, J., & Newsham, G. (1998). Lighting Quality and Energy-Efficiency Effects on Task Performance, Mood, Health, Satisfaction, and Comfort. Journal of the Illuminating Engineering Society, 27(1), 107–129. Najib Taher Al-Ashwal is a Ph.D. candidate in School of Housing, Building, and Planning at University of Science Malaysia (USM). He earned an MSc in Architectural Engineering from King Fahd University of Petroleum and Minerals (KFUPM), Saudi Arabia in 2008. He holds a B.S of Eng. in Architecture from Sana’a University, Yemen. He is interested in energy saving architectures. Professor Dr. Ahmad Sanusi bin Hassan teaches in Architecture Programme at the School of Housing, Building and Planning, University Sains Malaysia (USM). He obtained Bachelor and Master of Architecture from the University of Houston, Texas, USA. He was awarded a PhD degree from the University of Nottingham, United Kingdom. He was promoted to Associate Professor and later Full Professor. His research focuses on computer simulation on daylighting and thermal comforts, architectural history and theory, and housing in urban design. He is one of the nine regional writers involved in the preparation of Guideline: Agenda 21 for Sustainable Construction in Developing Countries: A Discussion Document, which was launched at The Earth/World Summit, Johannesburg in September 2002. At the university, he lectures in architecture courses related to urban design, studio, history, Computer Aided Design (CAD), and computer movie animation. He has integrated all these specialisations into his research, teaching, consultation and publications. He had designed several architectural projects such as mosque, USM guest house and a proposal for low-cost houses for fishermen community.

*Corresponding authors (A. Abujrad). Tel: +60-126103872. E-mail: abugrad@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/097.pdf.

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EFFECTIVENESS OF SUBTERRANEAN HEAT USE IN AN EARTH TUBE COMMUNITY HOUSE Ayumi JIMBO a

, Hiroo TARUMI

Department of Architecture, Kanazawa Institute of Technology, JAPAN

ARTICLEINFO

Article history: Received 24 January 2018 Received in revised form 23 March 2018 Accepted 09 April 2018 Available online 12 April 2018

Keywords: Earth tube system; Subterranean heat use; Measurement survey; ventilation; in house humidity.

ABSTRACT

This study involves a year-round measurement survey of outside air and indoor outlet temperature and humidity for a community house with an earth tube system constructed in Japan. The effectiveness of using subterranean heat in a house in the Hokuriku region is examined by calculating heat extraction in summer and heat addition in winter. The main features of this research are as follows: (1) an earth tube system (total length approximately 125 m) is installed beside a house at a depth of 2 m to reduce excavation costs; (2) measurements are taken under the condition of a ventilation rate of 0.33times/h (ventilation air volume, approximately 260 ㎥/h), which represents a fresh air load reduction and (3) the sensible and latent heat of the heat extraction in summer and the heat addition in winter under Hokuriku climate conditions in Japan are analyzed. The thermal effect of an earth tube system in summer is larger than in winter. The peak in heat extraction by the earth tube system was -1722 MJ/month in July and the latent heat portion of -906 MJ/month has exceeded the sensible heat portion of -866 MJ/month. © 2018 INT TRANS J ENG MANAG SCI TECH.

1. INTRODUCTION In recent years, as the need for the development of low-carbon architecture increases, practical use of the natural energy that surrounds buildings is attracting attention. Earth tube systems make use of one such natural energy, subterranean heat. These systems reduce the fresh air load by introducing outside air through tubes that pass beneath the ground before blowing the air indoors. Preliminary calculations carried out using the formulas for periodic heat conduction in semi-infinite solids (Hasegawa, 1965) show that the depth at which subterranean temperature remains at roughly the annual mean outside air temperature is more than 5 or 6 m, depending on the values used for the thermal conductivity of the soil and the outside air temperature fluctuation in the region. However, using this depth for earth tube systems in real houses is difficult because of *Corresponding authors (A.JIMBO). Tel/Fax: +81-76-248-1100 E-mail: ayumi.jimbo@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/107.pdf.

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excavation costs and deterioration of the bearing capacity of the ground. The depth up to which sheet piling is not necessarily required during excavation is usually 2 m at most, depending on the actual conditions of the construction site. Therefore, in the present research study, a community house was constructed in Takaoka, Toyama with tubes installed beside the building at a buried depth of approximately 2 m. A measurement survey of subterranean heat use was conducted over a 1-year period, fiscal years 2013, and the results are reported herein. The objective of the study was to clarify from measurements the effectiveness of fresh air load reduction obtained through the use of an earth tube system at a buried depth of 2 m by understanding the relationships among outside air temperature and indoor outlet temperature according to the season, and by presenting analysis results focusing on winter heat gain and summer heat extraction, including the latent heat portion. The features of this study are as follows: (1) an earth tube system (total length approximately 125 m) is installed beside a house at a depth of 2 m to reduce excavation costs; (2) measurements are taken under the condition of a ventilation rate of 0.33 times/h (ventilation air volume, approximately 260 ㎥/h), which represents a fresh air load reduction and (3) the sensible and latent heat of the heat extraction in summer

and the heat addition in winter under Hokuriku climate

conditions in Japan are analyzed.

2. OVERVIEW OF MEASUREMENTS 2.1 HOUSE AND EARTH TUBE SYSTEM

An overview of the house and the earth tube system for which measurements were taken is

given in Table 1. Also, Fig. 1 shows the arrangement of tubes buried besides the building. The total floor area of the house is 237 m2 , and the air volume is 790 m3 . The value of a coefficient of heat loss based on Japanese Act on the Rational Use of Energy is 3.79 W/(m2·K). The northwest of the community house is a park, and the earth tube is laid in the site. Seven vinyl chloride (VU) tubes with diameter ø200 and length 15 m were arranged in parallel and connected to headers of diameter ø300. The total length of subterranean tubing was approximately 125 m (the underground passage distance of the branched air was approximately 35 m). Piping is a comb-like arrangement, and the arrangement interval is 1500 mm. The tubes were laid at a gradient of 1.0%, and a small pump was installed in a shallow sump in the east corner to form a system that draws up condensation water produced inside the tubes during summer. The forced draft fan which installed in the house is BFS-100SSU by Mitsubishi Electric Corp.

2.2 DETAILS OF MEASUREMENT SURVEY

The forced draft fan which installed in the community house is BFS-100SSU by Mitsubishi

Electric Corp. and was continuously operated regardless of a season and day and night through the survey period. The diffused air volume was approximately 260 m3/h with flow rate measuring instrument (KNS-300, Kona Sapporo Corporation, Sapporo, Japan). Since the air volume of the community house is 790 m3, the ventilation rate is 0.33 times/h. 108

Ayumi JIMBO, and Hiroo TARUMI

The measurements taken included the outside air temperature/humidity and the outlet temperature/humidity using a thermo-hygrometer with memory (at 30-minute intervals; TD-72U, T&D Corporation, Nagano, Japan). The site was visited and measurement data were collected approximately once every 4 to 6 weeks. Table 1: Overview of Takaoka earth tube community house Location Takaoka City,Toyama Prefecture Tootal floor area 237m 2 Over view of house Structure Two-story wooden building Month and year completed May 2013 Header Branch tube Material Rigid vinyl chloride Tootal length Approx. 125m Arrangement interval 1500mm Over view of tube 3 Air volume approx.260m /h Nominal diameter 300 φ 200φ Length 10150 mm 15000 mm No.of tubes 2 7

Figure 1: Plan of earth tube community house/tubing diagram and measurement locations. *Corresponding authors (A.JIMBO). Tel/Fax: +81-76-248-1100 E-mail: ayumi.jimbo@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/107.pdf.

109

3. RESULT AND DISCUSSION 3.1 YEAR-ROUND MEASUREMENT SURVEY OF OUTSIDE AIR, SUBTERRANEAN AND INDOOR OUTLET TEMPERATURES FOR EARTH TUBE SYSTEM Figure 2 shows the relationship between outside air (tube inlet) temperature/humidity and indoor outlet temperature. It shows the annual variation in daily mean values from May 2013 to April 2014. The monthly mean values for outside air and indoor outlet temperature/humidity are arranged in Table 2 along with a number of valid days used in the calculation.

100

20 .

Apr

Mar

Jan

Feb

Dec

Sep

Nov

Oct

Aug

Jul

Jun

-10

Relative humidity (%RH)

Outside air temperature Outside relative humidity

May

Temp erature(℃)

Outlet temperature Outlet relative humidity

Figure 2: Annual Variation in Daily Mean Values for Outside Temperature/Humidity, Indoor Outlet Temperature/Humidity (May 2013 to April 2014). Table 2: Monthly Values of Temperature and Relative Humidity. 2013 Oct Nov Dec

Jan

Mean, Feb Mar Apr Total

15.9 19.2 22.9 25.1 23.2 20.3 14.8 10.6

8.2

6.9

8.2

11.5 15.6

2.8

3.0

6.5

11.2 14.5

May Jun Temperature Relative humidity No. of valid days

Outlet

2014

Jul

Aug Sep

Outside air 18.4 21.9 26.6 27.8 22.6 18.4 10.1 Outlet

4.9

79.1 84.8 84.7 79.7 68.5 70.6 56.8 56.2 53.3 56.1 65.4 64.4 68.3

Outside air 74.3 80.1 74.6 73.0 78.2 80.0 78.0 84.1 77.6 74.7 72.9 67.7 76.3 16

349

Outlet temperature reaches a peak of 25.1 ºC in August, and the lowest value, 6.9 ºC, occurs in February. Outside air temperature peaks in August, 27.8 ºC, and is lowest in January, 2.8 ºC, followed by 3.0 ºC in February. From Figure 2 and Table 2, the period during which the outlet temperature is lower than the outside air temperature and the earth tube system functions as a cooling apparatus is roughly four months, from May through August in Hokuriku. On the other hand, the period during which the outlet temperature is higher than the outside air temperature and the tube system functions as a heating apparatus is approximately 6 months, from October through March. 110

Ayumi JIMBO, and Hiroo TARUMI

Looking at the data for monthly mean values of outlet relative humidity, from May to August, this value is high and is in the comparatively low state from November to next year February. When high values are 84.8%RH in June and 84.7% in July, low values are 53.3%RH in January, 56.1%RH in February and 56.2%RH in December etc. Differences in relative humidity between inlet and outlet of the earth tube system originate in heat extraction in summer and heat gain in winter. Particularly in summer months, there are days on which condensation of vapor contained in the air occurs as a result of passing inside the tubes. Figure 3 shows time- series data of monthly mean values for outlet temperature/humidity and outside air temperature/humidity.

Since outside air temperature becomes high in the daytime and

low in the nighttime, conversely, the relative humidity of the outside air is high in the nighttime and low in the daytime. The change of outlet air temperature passing the earth tubes becomes small and the difference in temperature through day and night is settled in less than 2 ºC. When seeing about the width of the upper and lower sides of the temperature data plotted, while the difference in outside air temperature is 30 ºC (2-32 ºC), it becomes 19 ºC (7-26 ºC) with outlet temperature. The width of the temperature is reduced to 2/3 by air ventilation using the earth tube system. Also about the relative humidity of outlet air, the change by time becomes smaller.

Figure 3: Annual variation in monthly mean values. The temperature and absolute humidity differences between the outside air and the indoor outlet are fundamental to the calculation of the amount of heat added/extracted by the earth tubes. The rise and fall of outlet temperature and absolute humidity relative to outside air temperature and absolute humidity was calculated for each month, as shown in Fig. 4 and 5. In the figure, the number of time which became a value of plus or a value of minus by monthly, and its average value are shown. The biggest difference between outlet temperature and outside air temperature in *Corresponding authors (A.JIMBO). Tel/Fax: +81-76-248-1100 E-mail: ayumi.jimbo@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/107.pdf.

111

summer was -3.9 ºC in July, followed by 3.5 ºC in August. The biggest difference in winter was +6.0 ºC in January, followed by +5.8 ºC in December. In terms of sensible heat, it is estimated that

(Outlet Temp erature) (Outside Air Temp erature) ( °C℃)

the amount of heat added in winter is larger than the amount of heat extracted in summer. 15 10 5

(57h)

(33h)

(34h)

(126h)

(417h)

(564h)

(661h)

(729h)

(694h)

(592h)

(540h)

(389h)

+ 1.0

+ 0.6

+ 0.5

+ 1.2

+ 2.2

+ 3.1

+ 5.2

+ 5.8

+ 6.0

+ 4.8

+ 3.5

+ 2.4

-3.2

-2.9

-3.9

-3.5

-1.8

-1.7

-0.9

-1.9

-2.0

-3.0

-2.4

(327h)

(686h)

(711h)

(618h)

(303h)

(180h)

(59h)

(15h)

(80h)

(204h)

(307h)

May

Jun.

Jul.

Aug.

Sep.

Oct.

Nov.

Dec.

Feb.

Mar.

Apr.

0 -5 -10 -15

(50h)

Jan.

(Outlet Absolute Humidity )(Outside Absolute Humidity ) (g/kg(DA))

Figure 4: Annual variation in monthly mean values for (outlet temperature) – (outside air temperature). 4.0 3.0 2.0

(19h)

(25h)

(59h)

(78h)

(34h)

(295h)

(261h)

(297h)

(324h)

(291h)

(428h)

(197h)

+ 0.6

+ 0.2

+ 0.5

+ 0.6

+ 0.4

+ 0.5

+ 0.3

+ 0.2

+ 0.3

+ 0.2

+ 0.3

+ 0.4

-1.2

-1.5

-1.7

-1.4

-0.5

-0.3

-0.2

-0.3

-0.6

(365h)

(695h)

(685h)

(666h)

(686h)

(449h)

(459h)

(447h)

(420h)

(381h)

(316h)

(499h)

May

Jun.

Jul.

Aug.

Sep.

Oct.

Nov.

Dec.

Jan.

Feb.

Mar.

Apr.

1.0 0.0 -1.0 -2.0 -3.0 -4.0

Figure 5: Annual variation in monthly mean values for (outlet absolute humidity) – (outside air absolute humidity). To the next, looking at the absolute humidity difference, the biggest value in summer was -1.7 g/kg(DA) in July. The difference has become -1.0 g/kg(DA) or more from May to September, and latent heat removal by the earth tube system is expected in this period. The scatter diagram in Figure 6 shows the seasonal characteristics of the relationship between outside air temperature and indoor outlet temperature. After plotting the daily mean values of outlet temperature versus outside air temperature, simple linear regression was used to obtain the relationship represented by the following equation: y = 0.65x + 6.20 (ºC)

(1),

The correlation coefficient in this case is high, at 0.95, and looking at the data by season, it is clear that it transitions in a counterclockwise elliptical manner. During spring (April/May, ○) and fall (October/November, △), when the outside air temperature is around 15ºC, temperatures are below and above the regression line, respectively. In other words, indoor outlet temperatures are distributed below the regression line in spring, because subterranean temperatures are low, and Ayumi JIMBO, and Hiroo TARUMI 112

above the regression line in fall, because subterranean temperatures are high. Moreover, this figure shows that outlet temperatures are in the tendency which will be around 25-26 ºC in the time of summer outside air temperature being 30 ºC and will be around 6-7 ºC in the time of winter outside temperature being 0 ºC.

3.2 ANALYSIS OF AMOUNT OF HEAT EXTRACTION/ADDITION BY EARTH TUBE SYSTEM Figure 7 shows the results of calculation of the daily heat extraction and heat addition amounts at an air exchange rate of 0.33 times/h via the earth tube system.

The results are based on the

difference in temperature and humidity between the outside air and the indoor outlet measured at 30-minute intervals. Heat gain is shown as a positive value and heat extraction as a negative value; the dark orange indicates sensible heat and the light orange indicates latent heat. This latent heat portion was evaluated as extracted heat when the absolute humidity of air passing through the tubes decreased and as gained heat when it increased.

Details of the

calculation of the amount of latent heat are given in the Appendix.

Summer (Jun. to Sep.) Winter (Dec. to Mar.)

Spring (Apr.,May) Fall (Oct.,Nov.)

°C) Outlet Temperature (℃

30 25 20 15 10

y = 0.65x + 6.20 R = 0.95

-5

0 -5

Outside Air Temperature (℃ °C)

Figure 6: Relationship between outside air temperature and earth tube system outlet temperature. Looking at the entire year-long period, the trend is mainly heat extraction from May to September and mainly heat gain from mid-October to mid-March. The reason for the days with high values of heat extraction in the end of March 2014 is that outside air temperature rose, which is very unusual for that time of year. Latent heat extraction, which occurs when outside air with high temperature and humidity enters the earth tube system, occurs during the period May to September, *Corresponding authors (A.JIMBO). Tel/Fax: +81-76-248-1100 E-mail: ayumi.jimbo@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/107.pdf.

113

and days with high latent heat extraction values can be found in June and July. During this period, there are also days on which latent heat gain due to evaporation of condensation water inside the tubes occurs, but compared to the overall amounts over the year, latent heat extraction is greater. The maximums of heat extraction in summer are approximately 85 MJ/day, and the maximums of heat gain in winter are about 75 MJ/day. The latent heat portion has exceeded the sensible heat portion from May to September. Condensation water produced inside the earth tubes during summer draws up at a sump. Sensible Heat

Latent Heat

75 50 25 0 -25 -50

Apr.

Mar.

Feb.

Jan.

Dec.

Nov.

Oct.

Sep.

Aug.

Jun.

-100

Jul.

-75 May

Amount of Heat (MJ/day)

100

Figure 7: Amount of heat extraction/gain by earth tube system.

H ea t g a in H ea t e xtru ctio n

Sensible Heat

Amount of Heat (MJ/month)

2000 1500 1000 17 33

500 0

5 6

24 6

37 48

9 293

-866

-1000

-171 -603 -906 -745 -676 -623 -626 -809 -740

-1500 -2000

May

Jun.

Jul.

Aug.

Sep.

( M J/yea r) D e c. to M a r. + 33 1 + 549 1 + 516 0 D e c. to M a r. -233 6 -553 6 -320 0

Latent Heat 41 68 65 1326 1290 53 1071 887 104 112 540 586

-103 -31 -4 -160 -111 -79

-500

M a y to Ap r. + 59 8 + 698 8 + 639 0 M a y to Ap r. -360 6 -824 4 -463 8

Oct.

Nov.

Dec.

63 304

-30 -65

-49 -191 -70 -85 -259 -242

Jan.

Feb.

Mar.

Apr.

Figure 8: Monthly mean heat extraction/gain by earth tube system. Figure 8 shows amounts of heat extraction/gain by the earth tube system by the month. When calculating the numeric values categorized by the month in this paper, the daily mean values for the Ayumi JIMBO, and Hiroo TARUMI 114

pertinent month were determined using the valid data from a 1-year period, and then multiplied by the number of months and days. From the figure, the peak in heat extraction was in July and, adding together the sensible heat portion of -866 MJ/month and the latent heat portion of -906 MJ/month, it amounted to −1772 MJ/month. Heat extraction in June was approximately 81% of that in July at -1432 MJ/month (sensible heat portion: -623 MJ/month, latent heat portion: -809 MJ/month) and in August was approximately 80% of that in July at

-1416 MJ/month (sensible heat portion: -676

MJ/month, latent heat portion: -740 MJ/month). The peak in heat gain was in December and amounted to +1326 MJ/month of sensible heat. However, January had a heat gain approximately 97% of that in December at 1290 MJ/month of sensible heat. Totals for the year were as follows: The sensible heat portion of heat extraction was -3606 MJ/year and the latent heat portion of heat extraction was -4638 MJ/year, giving a subtotal of -8244 MJ/year. The sensible heat portion of heat gain was +6390 MJ/year and the latent heat portion of heat gain was +598 MJ/year, giving a subtotal of +6988 MJ/year; these results apply when the earth tube system is operated continuously throughout the year. In the Hokuriku Region, the period during which heat extraction can be expected is from June to September, and heat gain can be expected from November to March. Summing heat extraction and heat gain for each of these periods, the amount of heat extraction is found to be -5536 MJ/year over 4 months, and the amount of heat gain is found to be +5491 MJ/year over 5 months. As shown in Fig. 4, comparing only the earth tube system outlet temperature and the outside air temperature leads to the conclusion that the effectiveness of using subterranean heat is greater in winter. However, by including enthalpy of latent heat extraction in the evaluation, it was shown that the effectiveness of the earth tube system is actually greater in the summer in the Hokuriku region.

4. CONCLUSION This paper examined the effectiveness of using subterranean heat in the community house in the Hokuriku region by conducting a year-round measurement survey of outside air and indoor outlet temperature and humidity for an earth tube house constructed in Takaoka, Toyama and calculating heat extraction in summer and heat gain in winter. The research results are summarized below: 1) Using an earth tube system with a buried depth of 2 m, the total length of tubing, approximately 125 m and ventilation was carried out at an air exchange rate of 0.33 times/h. It was clarified that the monthly mean indoor outlet temperature could be maintained at around 3 to 4 ºC lower than the outside air temperature in summer and around 5 to 6 ºC higher than the outside air temperature during winter. The biggest difference between outlet temperature and outside air temperature in summer was -3.9 ºC in July, and the biggest difference in winter was +6.0 ºC in January. The fall of the absolute humidity of outlet air in comparison with outside air was remarkable in May to September, and the values were -1.2 g/kg(DA) to -1.7 g/kg(DA). *Corresponding authors (A.JIMBO). Tel/Fax: +81-76-248-1100 E-mail: ayumi.jimbo@gmail.com. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/107.pdf.

115

2) The peak in heat extraction by the earth tube system was -1722 MJ/month in July and the latent heat portion of -906 MJ/month has exceeded the sensible heat portion of -866 MJ/month. The peak in heat gain was +1367 MJ/month in December. In the heat acquisition which occurs in winter, there is the feature that the amount of sensible heat occupies most among the total heat, such as approximately 97% in December.

Moreover, when evaluated including latent heat

removal, it becomes clear that the thermal effect of an earth tube system in summer is larger than in winter, even in north latitude 36-degree Takaoka City.

5. ACKNOWLEDGEMENTS Part of the research funding used in this investigation was made possible by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) as part of the Supported Program for the Strategic Research Foundation at Private Universities, 2013-2015. We note this here and express our gratitude.

6. APPENDIX The following formulae were used to calculate latent heat gain/extraction (Inoue 2008): h = ha + x·hv

(A.1)

ha = 1.006·t hv = 2501 + 1.805t

(A.2) (A.3)

x = 0.622pv/(P – pv)

(A.4)

pv = φ·ps/100

(A.5)

ps = 133.3exp(18.808t + 361.52/t + 237.54)

(A.6)

Here, h: Specific enthalpy [kJ/kg’] ha: Specific enthalpy of dry air [kJ/kg’] x: Absolute humidity [kg] hv: Specific enthalpy of water vapor [kJ/kg] t: Temperature [ºC] pv: Partial pressure of water vapor [kPa] P: Standard atmospheric pressure, 101.325 [kPa] φ: Relative humidity [%] ps: Saturated water vapor pressure [Pa] Results based on the above formulae are multiplied by the house’s ventilation air volume (260 ㎥/h) at 0.33 times/h.

7. REFERENCES Hasegawa, F. (1965). Chapter 7: Unsteady State Heat Conduction, Architectural Planning and 116

Ayumi JIMBO, and Hiroo TARUMI

Design Theory. Maruzen Co., Ltd., Inoue, U. et al. (2008). Handbook of Air Conditioning, The 5th edition of revision. Maruzen Co. Ltd., Tarumi, H. and Minohara Y. (2010). Surveillance Study on the Subterranean Thermal Use Effect of a Heat & Cool Tube Residence, About the detached model house which located in Hokuriku region. Journal of Environment Engineering, Architectural Institute of Japan, Vol. 75 No. 651, 423-429 Tarumi, H., Jimbo, A., Iida T., Yokoyama T. (2016). Cooling and Heating Effects of Earth-tube Laid Underground Depth of 2 Meters, Investigation through one year at a community center in Takaoka City. Journal of Technology and Design, Architectural Institute of Japan, Vol.22, No.52, 1035-1040 Tarumi, H., Jimbo, A., Shioya M., Iwase K. (2017). Surveillance Study on the Thermal Effect of a Heat/Cool Trench, A case of school building. Journal of Technology and Design, Architectural Institute of Japan, Vol.23, No.54, 573-578

Ayumi JIMBO is a graduate student of Department of Architecture at Kanazawa Institute of Technology, Japan. The present subject of research is subterranean heat use through the ventilation in the trench of a building. She is going to join Shimizu Corporation after graduate school completion.

Professor Dr. Hiroo TARUMI is Professor in Department of Architecture at Kanazawa Institute of Technology. He obtained his Doctor of Engineering degree from Tokyo Institute of Technology. He works in the area of architectural environmental engineering and building equipment. Dr. TARUMI focuses on the application of the natural power sources to buildings and houses.

*Corresponding authors (A.JIMBO). Tel/Fax: +81-76-248-1100 E-mail: ayumi.jimbo@gmail.com. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/107.pdf.

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EFFICACY OF DOUBLE SKIN FAÇADE ON ENERGY CONSUMPTION IN OFFICE BUILDINGS IN PHNOM PENH CITY a

Yonghuort Lim and Mohd Rodzi Ismail a b

Institute of Technology of Cambodia, PO Box 86, Russian Conf. Blvd. Pnom Penh, Cambodia School of Housing, Building and Planning, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia

ARTICLEINFO

Article history: Received 15 January 2018 Received in revised form 26 March 2018 Accepted 12 April 2018 Available online 18 April 2018

Keywords: Cavity depth Building energy simulation; End-use energy; Cooling energy; Laminated glass; DSF.

ABSTRACT

The use of glazed façades for office buildings in Phnom Penh city has been increasing these days, and those conventional façades lead to a high energy demand especially for cooling purpose in the buildings. Almost fifty percent of the overall annual energy has been consumed by the commercial sector in Cambodia, and it keeps growing year after year. Pertaining to the matter, the use of double skin façade (DSF) as one of the approaches to improve building energy performance has been studied. The objectives of this study are, to assess the potential of DSFs on building energy efficiency, and to propose its optimum configurations for office buildings in Phnom Penh city. To do so, the different DSF parameters consisted of cavity depth, glass materials for interior and exterior layer and shading device for DSFs were investigated by using the whole building energy simulation program, EnergyPlusTM. The primary result shows that DSF is a good technique to achieve building energy efficiency in Phnom Penh city, but it does require a proper design to avoid unexpected issues such as excessive solar radiation and thermal transfer into the building through the building’s façade. The optimum parameters of DSF found in the study are 500 mm cavity depth, bronze laminated glass for the internal, and external layers of DSF, and external blind louvre. The combination of all optimum parameters could potentially reduce about 34% of the annual energy demand. © 2018 INT TRANS J ENG MANAG SCI TECH.

1. INTRODUCTION These days, the concern on the sustainable building development is growing around the world, and one among major elements is energy saving in buildings (Chan et al., 2009). In a typical commercial building, air-conditioning system is the main electricity consumer which accounts for more than 40% of the entire electricity consumption of a building, and one of the principal thermal *Corresponding authors (Mohd Rodzi Ismail). Tel: +60-4-6532841. E-mail: rodzi@usm.my. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/119.pdf.

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loads in the building façade heat gain is the heat transfer through window glazing of the building’s exterior wall (Chan et al, 2009). Consequently, various energy saving methods have been introduced to block solar radiation in the buildings (Hong et al., 2013). Double skin façade (DSF) is one of the approaches used for solving the issues of energy performance in the buildings. It is a pair of walls or glass skins separated by air cavity which can be expanded from 20 cm to several meters, where the internal skin is normally a conventional façade, while the external layer is normally covered up the main layer (typically glazing) to create cavity space for insulation purpose (Uuttu, 2001). In addition, the ventilation mode used in the cavity of DSFs could be passive, active or hybrid ventilation system (Streicher et al., 2005). Over the last 10 to 15 years, the practice of DSFs has significantly increased, primarily due to the profits attributed to them regarding the improved energy efficiency and enhanced day lighting (Author & Pollard, 2000). The vast majority of DSFs have been built in Europe, especially Northern Europe, principally because of their huge heating requirements, the high cost of energy, and the desire for improved natural light (Author & Pollard, 2000). However, Streicher et al. (2005) stated that DSFs is mostly used in Europe because it contributes to the architectural trend which is commonly known for aesthetic of transparent glass, improvement, and stabilisation of the internal environment, acoustic quality protection, and decreasing of energy consumption. Nowadays, the potential of using DSFs for buildings in climates other than Europe has also been found. For instance, Wong et al. (2008) found that a substantial energy saving is possible, if passive ventilation can be exploited by using DSFs in hot and humid climate region. Moreover, based on the study on the effect of double glazed facade on energy consumption, thermal comfort, and condensation for a typical office building in Singapore by Hien et al. (2005), double glazed facade is a good approach to improve thermal comfort in a multi-storey office building. However, the potential of using the system in other climates has not been fully investigated yet. Besides, the climatic condition, and local characteristics such as temperature, solar radiation etc., need to be considered in the design of DSFs to achieve reduction in energy consumption (Azarbayjani, 2014). Also, Rahmani et al. (2012) stated that accurate planning strategies must be followed to reduce overheating, and get more benefit out of DSF layering. Therefore, DSFs need to be designed based on the specific climatic behaviour of a location. In a hot climate, the building could have high external heat loads to deal with for the whole or part of the year. For the conventional building systems, natural or low energy systems such as shading and fans are usually used to provide comfort cooling. Nevertheless, the nature of current buildings, and various user expectations can make it hard to implement these strategies, thus the high external and internal loads encourages the necessary need of air-conditioning system to provide cooling for all or a major portion of the year (Author & Pollard, 2000). For a hot and humid climate country like Cambodia, the energy demand for the air-conditioning system in buildings accounted for the main proportion of energy consumption in 120

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the operation of the buildings. About 48 percent of total annual energy was consumed by commercial sector in Cambodia, and the demand of energy keeps significantly rising every year (Cambodia National Energy Statistics, 2016). At present, the conventional façades of office buildings in Phnom Penh city allow extreme thermal transfer through the building envelope, and cause unsatisfied atmosphere in the buildings. Due to the architects’ desire, conventional glass materials are still preferably used for the skin of the buildings even though it causes significant heat gain into the space. Various energy efficiency strategies have been introduced by many literature (Hong et al., 2013). DSF is one of the potential strategies that can be adopted to improve the energy performance of the buildings. Hence, this study was conducted with the objectives to assess the potential of DSFs on building energy efficiency, and to propose its optimum configurations for office buildings in Phnom Penh city.

2. LITERATURE REVIEW 2.1 DEFINITION DSFs are characterised inversely by the most critical researchers to explain the performances of the system. Outer façade, a halfway air space, and internal façade are included in the DFS system. Ventilation is applied, and permitted in the cavity space, while the climate, and acoustic are protected by the external layer, which also provides the thermal resistance. In addition, a movable shading gadget is typically used for better performance (Oesterle et al., 2001). Arons (2000) described DSF as a façade having two separated planar components that grants internal or external air to travel through its structure, in which it is also called a twin skin. According to Safer et al. (2005), DSF is a special type of envelope, where a second skin, usually a transparent glazing, is placed in front of a regular building facade. The air space in between or the channel, can be between 0.8 to 1.0 m, where it is ventilated naturally, mechanically, or using a hybrid system to diminish overheating problems in summer, and to contribute to energy savings in winter. Chan, et al. (2009) on the other hand termed DSF as a building facade covering one or several storeys with multiple glazed skins, where the skins can be air tight or naturally/mechanically ventilated. The outer skin is usually a hardened single glazing, and can be fully glazed, whereas the inner skin can be insulating double glazing, and is not completely glazed in most applications. The width of the air cavity between the two skins can range from 200 mm to more than 2 m. An air-tightened double skin facade can provide better thermal insulation for the building to reduce the heat loss in winter. On the other hand, moving cavity air inside a ventilated double skin facade can absorb heat energy from the sun-lit glazing, and reduce the heat gain as well as the cooling demand of a building. *Corresponding authors (Mohd Rodzi Ismail). Tel: +60-4-6532841. E-mail: rodzi@usm.my. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/119.pdf.

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Even though there are some unique definitions among the distinctive sources of writing, DSF has a common meaning i.e. a system of building that consists of two facades or skins, constructed in such a way that air flows in the intermediate space in between or cavity.

2.2 PERCEPTIONS ON DOUBLE SKIN FACADE In architecture, DSF plays an important role in exterior design. Its transparency provides good aesthetic, and daylight for buildings, and protects the interior space by giving the opening between two layers a ventilation system, which can be operated passively, actively or a combination of both. DSF not only provides a better visualisation, but also improves the indoor thermal comfort, visual comfort, natural lighting, and energy savings. According to Hendriksen et al. (2000), the transparency is frequently observed as the principle architectural purpose behind a twofold skin exterior, since it makes close contact with the environment. Transparent view to the outside, and sunshine levels are expanded when twofold skin exteriors are utilised instead of customary window surfaces. For engineering, DSF has its main roles and benefits regarding technical constructions and physical environment. According to Lee et al. (2002), the chief advantage of DSF is acoustics. In active areas such as the air terminal or high activity urban regions, DSF is utilised to decrease sound level by its second layer of glass screen in front of a traditional faรงade. Then again, if the air space in the outside layer is big enough to empower tolerable natural ventilation, operable windows behind this all-glass layer will bargain this acoustic advantage predominantly. Other than the acoustics, sun based extraction, and sun radiation load are controlled by shading framework situated in the moderate space between the outside glass faรงade and inside faรงade. It is like outside shading framework that sun-powered radiation load is obstructed before entering the building, while heat consumed by the cavity is drawn off through the outside skin by normal or mechanical ventilation framework. Basically, the primary purposes of DSF as characterised by Arons (2000) are aesthetics, passive ventilation, cost saving, sound diminishment, client control and comfort, occupant productivity related to surrounding environment, and additional security for buildings.

Figure 1: Classification of DSF (VDF means DSF) (BBRI, 2005) 122

Yonghuort Lim and Mohd Rodzi Ismail

2.3 CLASSIFICATION OF DOUBLE SKIN FACADE Classification of DSFs can be made according to the Ventilated Double Façade (VDF) classification (BBRI, 2005), that is based on the ventilation type, partitioning of the cavity, and mode of ventilation as summarised in Figure 1. Referring to the above classification, Streicher et al. (2005) explained that the type of ventilation refers to the driving forces at the origin of the ventilation of the cavity located between the two glazed façades, in which each ventilated double skin façade concept is characterised by only a single type of ventilation. The ventilation mode refers to the origin, and the destination of the air flowing in the ventilated cavity. It is independent of the type of ventilation applied. The partitioning of the cavity gives the information on how the cavity situated between the two glazed façades is physically divided. There are other strategies for classification of DSF as well. Most of them are dependent on the design principle, for instance, the direction of air flow inside the intermediate space, the façade design and the arrangement of cavity system (Regazzoli, 2013). Similarly, Oesterle et al. (2001), classified the DSFs mostly by considering the geometry of the cavity. According to Poirazis (2004), the most well-known one is to categorise the façade according to its geometry. The four types mentioned are Box Façade, Corridor Façade, Shaft-Box Façade and Multi-Storey Façade as shown in Figure 2.

Box Façade

Corridor Façade

Shaft-Box Façade

Multi-Storey Façade

Figure 2: Types of double skin façade (after Regazzoli (2013)).

2.4 Technical Aspects of Double Skin Façade System 2.4.1 Cavity The depth of the cavity can be varied according to the different concept of utilising DSFs, in which it can be between 10 cm to more than 2 m. On the other hand, the width of the cavity affects the physical properties of the façade, and the way that façade is sustained. The parameters of DSFs including the aesthetics, types of shading device, the access for maintenance, and the ventilation modes is determined to consider the depth of the cavity (Sinclair et al., 2009 as cited in Ghaffarianhoseini et al., 2016). *Corresponding authors (Mohd Rodzi Ismail). Tel: +60-4-6532841. E-mail: rodzi@usm.my. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/119.pdf.

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The results from the study conducted on office buildings in a temperate climate by Regazzoli (2013) show that the most efficient façade construction combination is the 1000 mm Multi-Storey Double-Skin Façade with a regulating cavity. This combination managed to achieve an annual energy saving of about 16% as compared to the base model using a conventional single skin façade. According to Rahmani et al. (2012), who conducted their study in a fully air-conditioned office building in the tropical climate, the recommended cavity for DSF system is 1000 mm as it enhances the performance of DSF in lowering the solar heat gains. However, the system does not work efficiently if the cavity is more than 1000 mm. Aksamija (2009) also found that the ventilation of air cavity is essential in reducing the cooling loads, in which the 1000 mm cavity is the better parameter of DSF that increases the performance of DSF. 2.4.2 Glass Type Streicher et al. (2005) stated that the typology of the façade is the first consideration for the choice of the glass type for the internal and external walls of DSFs. If outdoor air is used to ventilate the façade, the internal wall is normally equipped with an insulating pane (thermal break), while the external wall is equipped with a single glazing. The opposite will be applied in case of indoor air is used for façade ventilation. On the other hand, Sinclair et al. (2009) mentioned that the glazing system design for a DSF depends on the climatic conditions of the project site, preferred ventilation and blind operating modes, and internal space requirements. Besides, Haase & Amato (2006) found in their study that the amount of heat gain through the building envelope can be reduced significantly by designing a ventilated DSF using two clear glazing in the internal and external layers with natural ventilation in the cavity. Similarly, Aksamija (2009), stated that the location of double glazing on the exterior skin improves the overall energy consumption, with high-performance e-glazing glass is the better parameter that enhances the performance of DSF. 2.4.3 SHADING DEVICE According to Oesterle et al. (2001), determining the effective characteristics of the sun shading in each case poses a special problem at the planning stage since the properties can vary considerably, according to the type of glazing and the ventilation of the sun shading system. They added that the sun shading provides either a complete screening of the area behind it or, in the case of the louvres it may be in a so-called “cut-off” position. Hence, for large-scale projects it is worth investigating the precise characteristics of the combination of glass and sun shading, as well as the proposed ventilation of the intermediate space in relation to the angle of the louvres. Regarding DSFs and shading devices, heat gain into buildings can possibly be reduced when the blinds are placed in the accurate location, and it is found that the blinds with light color are likely to offer more light into the facades (Baldinelli, 2009). Haase & Amato (2009) conducted an experiment on DSFs by placing blinds, and shading devices inside the cavity between the two layers to provide the shield against intrusion, direct sunlight, and glare. The results show that the exterior Yonghuort Lim and Mohd Rodzi Ismail 124

or mid pane types offer the decrease in solar heat gain. A proper control and adjustment of the blind could lead to a considerable amount of energy saving. In addition, Gavan et al. (2007) investigated the effect of ventilated DSF with venetian blinds on its energy performance. They found that the studied DSF shows reduction in energy consumption compared to a traditional façade, which indicates that shading devices have its influence on the performance of DSF.

3. Methodology A typical office building in Phnom Penh city as shown in Figure 3 was used as base case model for this study. Table 1 presents brief description about the building. To determine the optimum configurations of DSF, three strategies were adopted to analyse the energy performance of the building. EnergyPlus programme version 8.6.0 was used to perform the simulation of total energy use and for cooling purpose, along with OpenStudio, and Google SketchUp 2016 to model the interface of the studied office building as illustrated in Figure 4. Table 1: Building description.

Building type: Level:

Office 10 storeys

Floor: Internal partition:

Ground floor area:

230 m2

Glass type:

North length: South length:

17 m 12 m

Window shading: Lighting type:

East and west width: 15 m Total height: 34.93 m Front Orientation: North-west Wall: Roof ceiling:

Double brick plaster 100 mm concrete and 10 mm plasterboard

Cooling type: Air-conditioning: Operating schedule: Working day: Weather data:

100 mm concrete slab Lightweight gypsum plasterboard with 100 mm cavity Laminated glass 6 mm + 1.14 mm + 6 mm Vary from floor to floor Open fluorescent luminaire/Recessed round downlight Air cooled Variable Air Volume (VAV) system 9:00 to 19:00 Monday to Friday Phnom Penh city

Figure 3: Base case

Figure 4: Modelling of single skin, and double skin

building, B-Ray tower.

façade buildings.

*Corresponding authors (Mohd Rodzi Ismail). Tel: +60-4-6532841. E-mail: rodzi@usm.my. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/119.pdf.

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The first strategy was to find the optimum cavity depth of DSFs, thus three categories of DSF configurations were proposed for the study. At this point, every aspect of DSF model was based on the base case model as shown in Table 2, except the DSF configurations, and parameters including ventilation type, external materials, and shading devices were based on other previous studies, in which they were conducted in similar context. Category DSFs configuration Ventilation type Cavity depth Internal glass External glass Shading device

Table 2: DSF models with different cavity depth. C-1 Multiple-storey DSF Natural ventilation 500 mm Bronze laminated glass Clear e-glazing No shading device

C-2 Multiple-storey DSF Natural ventilation 1000 mm Bronze laminated glass Clear e-glazing No shading device

C-3 Multiple-storey DSF Natural ventilation 1500 mm Bronze laminated glass Clear e-glazing No shading device

The second strategy was to determine the optimum glazing materials used for DSF parameters. In this section, base case glass, and two new proposed glass materials were used. Next, the result of the optimum cavity from strategy one was applied into strategy two for investigation. Four categories of DSF were proposed and tabulated in Table 3. Table 3: DSF models with different glazing materials.

Category G-1 G-2 G-3 G-4 G-5 DSF Multiple-storey Multiple-storey Multiple-storey Multiple-storey Multiple-storey configuration DSF DSF DSF DSF DSF Ventilation Natural Natural Natural Natural Natural type ventilation ventilation ventilation ventilation ventilation Cavity depth 500 mm 500 mm 500 mm 500 mm 500 mm Internal glass Clear Clear double Clear Clear double Bronze e-glazing glazing e-glazing glazing laminated glass External Clear double Clear Clear Clear double Bronze glass glazing e-glazing e-glazing glazing laminated glass Shading No shading No shading No shading No shading No shading device device device device device device

The third strategy was determining the optimum shading devices for DSFs. Like strategy one and strategy two, three categories of DSF were proposed for investigation with different shading devices as illustrated in Table 4. Similarly, the optimum results from strategy one and strategy two were also applied into strategy three for investigation. Category DSF configuration Ventilation type Cavity depth Internal glass External glass Shading device

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Table 4: DSF models with different shading devices

S-1 Multiple-storey DSF Natural ventilation 500 mm Bronze laminated glass Bronze laminated glass No shading device

S-2 Multiple-storey DSF Natural ventilation 500 mm Bronze laminated glass Bronze laminated glass Internal shade rolling blind

Yonghuort Lim and Mohd Rodzi Ismail

S-3 Multiple-storey DSF Natural ventilation 500 mm Bronze laminated glass Bronze laminated glass Internal blind louvre

S-4 Multiple-storey DSF Natural ventilation 500 mm Bronze laminated glass Bronze laminated glass External blind louvre

4. RESULTS AND DISCUSSION 4.1 ANNUAL ENERGY CONSUMPTION OF STRATEGY ONE The results of simulation from strategy one shows that the buildings with DFS system consume less energy than the single skin faĂ§ade building as summarized in Figure 5. A gradual reduction of the end-use energy occurs from the model with cavity depth of 1500 mm to 500 mm, i.e. 374406 kWh to 368698 kWh. Table 5 gives the amount of energy savings, showing that the DSF model with 500 mm cavity depth (C-1) consumes the lowest energy, in which the saving of up to 56882 kWh or 13.37% can be achieved annually. The results also show a similar trend of reduction in cooling energy use. Percentage wise, more saving is achieved for the annual cooling energy, i.e. 17.09%.

Figure 5: Annual end-use and cooling energy of DSF models with different cavity depth [kWh]. Table 5: Annual end-use energy [kWh], and annual saved energy [kWh], [%]. Category Annual end-use energy [kWh] Annual cooling energy [kWh] Annual saved energy (End-use) Annual saved energy (Cooling)

Base case 425580 227972 [kWh] [%] [kWh] [%]

C-1 368698 189014 56882 13.37 38958 17.09

C-2 371796 191119 53784 12.64 36853 16.17

C-3 374406 192920 51174 12.02 35052 15.38

DSF with 500 mm cavity has the highest capability to reduce the energy consumption in the building as its solar radiation level is found to be lesser than the 1000 mm and 1500 mm cavities. The bigger the cavity depth, the higher solar radiation received. It could also be due the optimum depth of the cavity that provides a better stack effect to remove excessive heat from its space. Generally, all DSF categories in strategy one can reduce around 12% and 15% of the annual *Corresponding authors (Mohd Rodzi Ismail). Tel: +60-4-6532841. E-mail: rodzi@usm.my. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/119.pdf.

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end-use energy, and cooling energy respectively.

4.2 ANNUAL ENERGY CONSUMPTION OF STRATEGY TWO The optimum cavity depth found in strategy one is applied into this second strategy to determine the optimum glass properties for DSF configurations. Figure 6 presents the annual energy demand of each category. Surprisingly, the new proposed glass materials used in model G-1, G-2, G-3, and G-4 cause the building to consume more energy than the base case model. The range of increase is approximately between 1 to 5 %, combining the end-use and cooling energy. Nevertheless, comparing these four models, G-1 which uses clear low-e glass as the internal skin, and clear double glazed as the external skin, consumes less energy than the others, i.e. 431192 kWh, even though the amount is 1.32% more than the annual end-use energy.

Table 6 summarises the

annual energy use and saving for strategy 2, in which negative means excess in energy use.

Figure 6: Annual end-use and cooling energy of DSF with different glass materials [kWh].

Table 6: Annual end-use energy [kWh], annual saved energy [kWh], [%], and exceeded energy [%]. Category Annual end-use energy [kWh] Annual cooling energy [kWh] Annual saved energy (End-use) Annual saved energy (Cooling)

Base case

G-1

G-2

G-3

G-4

G-5

425580

431192

442491

438735

433878

325945

227972

231143

238888

236234

233117

160054

-5612 -1.32 -3171 -1.39

-16911 -3.97 -10916 -4.79

-13155 -3.09 -8262 -3.62

-8298 -1.95 -5145 -2.26

99635 23.41 67918 29.79

[kWh] [%] [kWh] [%]

The results show that G-5 is the optimum model, which has the lowest annual energy demand 128

Yonghuort Lim and Mohd Rodzi Ismail

with 325945 kWh or about 23% decrease in annual end-used energy from the base case. This indicates that the laminated glass has a higher capability to block solar radiation through the window into the cavity and building. Besides, based on this finding, the color of glazing materials could also help in reducing the heat transfer, thus heat gain into the cavity.

4.3 ANNUAL ENERGY CONSUMPTION OF STRATEGY THREE Strategy three utilizes the optimum results from strategy one and strategy two, i.e. 500 mm cavity depth, and bronze laminated glass for internal and external skins, to determine the optimum shading device of DSF. Results in Figure 7 shows that the DSF without shading device (S-1) consumes the highest annual energy compared to others, excluding base case. On the other hand, the DSF with external blind (S-4) contribute to the highest annual end-use energy saving of about 34% (280716 kWh) as shown in Table 7.

Figure 7: Annual end-use and cooling energy of DSF with different shading devices [kWh]. Table 7: Annual end-use energy [kWh], and annual saved energy [kWh], [%]. Category

Annual end-use energy [kWh] Annual cooling energy [kWh] Annual saved energy (End-use) Annual saved energy (Cooling)

Base case

425580 227927 [kWh] [%] [kWh] [%]

S-1

325883 160054 99697 23.43 67918 29.79

S-2

287988 134367 137592 32.33 93605 41.06

S-3

304948 145839 220632 28.35 82133 36.03

S-4

280716 129565 144864 34.04 98407 43.17

Interestingly, DSF with internal rolling blind (S-2) reduces more energy than internal blind louvre (S-3), but consumes more energy than the external blind louvre (S-4). This indicates that the external louvre has more ability to block solar radiation through the window into the building. The internal, and external blinds used have the same properties, and physical characteristics except for *Corresponding authors (Mohd Rodzi Ismail). Tel: +60-4-6532841. E-mail: rodzi@usm.my. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/119.pdf.

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the locations where there are placed. Despite those similarities, the results show different capabilities in energy savings. Therefore, besides the properties of shading devices, the location of the devices is also relevant to achieve savings in energy use.

5. CONCLUSION DSF has its potential for energy efficiency in office buildings in Phnom Penh city. The results of the study show that the system contributes to a better energy performance by reducing the annual end-use and cooling energy demand in the studied building.

Nevertheless, a proper design of DSF

is required to avoid the unexpected issues on building envelopes such as excessive solar radiation and thermal transfer into the space. The recommended configurations of DSF parameters for office buildings in Pnom Penh city are 500 mm cavity depth, bronze laminated glass for the internal, and external layers of DSF, and external blind louvre to achieve as minimum as 34% saving in the annual energy demand.

6. ACKNOWLEDGEMENTS The first author would like to thank the Ministry of Education, Youth and Sports of the Kingdom of Cambodia, through the Department of Higher Education, for sponsoring the postgraduate study, M.Sc. in Building Technology, at Universiti Sains Malaysia, thus this research.

7. REFERENCES Aksamija, A. (2009). Context-Based Design of Double Skin Facades: Climatic Considerations during the Design Process. Perkins+ Will Research Journal, 1(1). Arons, D. M. (2000). Properties and Applications of Double-Skin Building Facades (Doctoral dissertation, Massachusetts Institute of Technology). Author, L. & Pollard, B. (2000). Double Skin Faรงades More Is Less? In Proc. Int. Sol. Energy Soc. Conf (Vol. 21, pp. 1-25). Azarbayjani, M. (2014). Comparative Performance Evaluation of a Multistory Double Skin Faรงade Building in Humid Continental Climate. In ARCC Conference Repository. Baldinelli, G. (2009). Double Skin Faรงades for Warm Climate Regions: Analysis of a Solution with an Integrated Movable Shading System. Building and Environment, 44(6), 1107-1118. BBRI (2005). Ventilated Double Facades - Classification and Illustration of Facade Concepts: Department of Building Physics, Indoor Climate and Building Services Cambodia National Energy Statistics. (2016). Ministry of Mines and Energy, Cambodia and Economic Research Institute for ASEAN and East Asia, 2016. http://www.eria.org/RPR_FY2015_08.pdf Chan, A. L. S., Chow, T. T., Fong, K. F. & Lin, Z. (2009). Investigation on Energy Performance of Double Skin Facade in Hong Kong. Energy and Buildings, 41(11), 1135-1142. Gavan, V., Woloszyn, M., Roux, J. J., Muresan, C. & Safer, N. (2007). An Investigation into the Effect of Ventilated Double-Skin Facade with Venetian Blinds: Global Simulation and 130

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Assessment of Energy Performance. In Proc. of X IBPSA Conference BS (pp. 127-133). Ghaffarianhoseini, A., Berardi, U., Tookey, J., Li, D. H. W. & Kariminia, S. (2016). Exploring the Advantages and Challenges of Double-Skin Façades (DSFs). Renewable and Sustainable Energy Reviews, 60, 1052-1065. Haase, M. & Amato, A. (2006). Design Considerations for Double-Skin Facades in Hot and Humid Climates. Envelope Technologies for Building Energy Efficiency Vol.II-5-1. Haase, M. & Amato, A. (2009). A Study of the Effectiveness of Different Control Strategies in Double Skin Facades in Warm and Humid Climates. Journal of Building Performance Simulation, 2(3), 179-187. Hendriksen, O. J., Sorensen, H., Svenson, A. & Aaqvist, P. (2000). Double Skin Façades—Fashion or a Step towards Sustainable Buildings. Proceedings of ISES, Eurosun, 2000. Hien, W. N., Liping, W., Chandra, A. N., Pandey, A. R. & Xiaolin, W. (2005). Effects of Double Glazed Facade on Energy Consumption, Thermal Comfort and Condensation for a Typical Office Building in Singapore. Energy and Buildings, 37(6), 563-572. Hong, T., Kim, J., Lee, J., Koo, C. & Park, H. S. (2013). Assessment of Seasonal Energy Efficiency Strategies of a Double Skin Façade in a Monsoon Climate Region. Energies, 6(9), 4352-4376. Lee, E., Selkowitz, S., Bazjanac, V., Inkarojrit, V. & Kohler, C. (2002). High-Performance Commercial Building Façades. Building Technologies Program, Environmental Energy Technologies Division, Ernest Orlando Lawrence Berkeley National Laboratory (LBNL). University of California, Berkeley, USA (LBNL–50502) Web address: http://gaia. lbl. gov/hpbf/documents/LBNL50502. pdf. Oesterle, E., Leib, R. D., Lutz, G. & Heusler, B. (2001). Double Skin Facades: Integrated Planning: Building Physics. Construction, Aerophysics, Air-Conditioning, Economic Viability, Prestel, Munich. Poiraziz, H. (2004) Double Skin Facades for Office Buildings. Division of Energy and Building Design Department of Construction and Architecture Lund Institute of Technology Lund University, 2004 Report EBD-R--04/3 Rahmani, B., Kandar, M. Z. & Rahmani, P. (2012). How Double Skin Façade’s Air-Gap Sizes Effect on Lowering Solar Heat Gain in Tropical Climate? World Applied Sciences Journal, 18(6), 774-778. Regazzoli, A. (2013). A Comparative Analysis on the Effect of Double- Skin Façade Typologies on Overall Building Energy Consumption Performance in a Temperate Climate. Supervisor: Rory Greenan. Safer, N., Woloszyn, M. & Roux, J. J. (2005). Global Modelling of Double Skin Facades Equiped with Venetian Blind Model Based on CFD Approach. In CISBAT 2005. Sinclair, R., Phillips, D. & Mezhibovski, V. (2009). Ventilating Façades. ASHRAE Journal, 51 (4), pp. 16-27 Streicher, W. (2005). WP 1 Report ‘State of The Art’, BESTFAÇADE, Best Practice for Double Skin Façades (Vol. 7, p. 38652). EIE/04/135. Uuttu, S. (2001). Study of Current Structures in Double-Skin Facades. MSc thesis in Structural Engineering and Building Physics. Department of Civil and Environmental Engineering, Helsinki University of Technology (HUT), Finland. Web address: *Corresponding authors (Mohd Rodzi Ismail). Tel: +60-4-6532841. E-mail: rodzi@usm.my. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/119.pdf.

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http://www.hut.fi/Units/Civil/Steel/SINI2.PDF Wong, P. C., Prasad, D. & Behnia, M. (2008). A New Type of Double-Skin Faรงade Configuration for the Hot and Humid Climate. Energy and Buildings, 40(10), 1941-1945.

Yonghuort Lim received his B.Arch. from the Royal University of Fine Arts (RUFA), Cambodia, in 2016. He received a Ministry of Education, Youth and Sports of the Kingdom of Cambodia scholarship to continue his postgraduate study at Universiti Sains Malaysia, where he obtained his M.Sc. in Building Technology in 2017. Currently, he works at the Institute of Technology of Cambodia (ITC), a public institution in his country. Mohd Rodzi Ismail, is an Associate Professor in the Building Technology programme at the School of Housing, Building & Planning, Universiti Sains Malaysia. He graduated with B.Sc. HBP Hons. specialising in Building Engineering, and M.Sc. in Building Technology degrees from the Universiti Sains Malaysia. He obtained his Ph.D. from the University of Liverpool, United Kingdom. His research interests are in the areas of indoor environment, and building energy management.

132

Yonghuort Lim and Mohd Rodzi Ismail

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies http://TuEngr.com

A STUDY OF BUILDING RENOVATION TO BE A NET ZERO ENERGY BUILDING: CASE STUDY OF ENERGY MANAGEMENT AND INNOVATION OFFICE, BUILDING AND FACILITY DIVISION, KHON KAEN UNIVERSITY Chumnan Boonyaputthipong a

Faculty of Architecture, Khon Kaen University, THAILAND

ARTICLEINFO

Article history: Received 15 January 2018 Received in revised form 03 April 2018 Accepted 16 April 2018 Available online 18 April 2018

Keywords: Solar-cell; Energy Saving; Building Renovation; Photovoltaic installation, PV cell.

ABSTRACT

Energy consumption in Khon Kaen University, Thailand, has each year increased due to the demand for facility and buildings. The Energy Management and Innovation Office is the main sector that has a responsibility to promote and organize energy use within the campus. Renovation its building to be net-zero energy building will be a learning case for students and community. Energy saving factors are also taken into the consideration. The record showed that the average of energy consumption in this building is 21,735.4 Kilowatt-hour per year or 59.55 Kilowatt-hour per day. So, by using 300 watts solar-cell panel, the number of solar panel for supporting the energy use in this building is 86 panels. The building has available roof area for the photovoltaic system installation comprising 86 solar panels faced to the south with service space between the panels. Finally, the result shows that the Energy Management and Innovation Office building can be a net zero energy building. This study result will be used as information for the future plan of the university. © 2018 INT TRANS J ENG MANAG SCI TECH.

1. INTRODUCTION Khon Kaen University is the largest university in the north-east region of Thailand. Energy consumption in Khon Kaen University increases due to the demand for facility and buildings each year. Khon Kaen University set up policies for saving energy on the campus including the renewable energy for the building. The Net Zero Energy Building is one of the solutions that have been done by the university. The office of Communication Affairs Division building, Khon Kaen University officially became the first Net Zero Energy Building in Thailand funded by Energy Policy and Planning Office, Ministry of Energy, Thailand.

This building is successfully renovated

the unused office building within the campus. It proved that the renewable energy, solar-cell, can *Corresponding authors (C.Boonyaputthipong). Tel/Fax: +66-81-8712385 E-mail: bchumn@kku.ac.th. ©2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/133.pdf.

133

substitute the energy use in the building, annually. Moreover, this building becomes the success example that draw the attention of other organizations countrywide to visit the university. The Energy Management and Innovation Office, Building and Facility Division office is the sector in Khon Kaen University that has a responsibility to promote and organize energy use within the campus. The office is an existing building that once used as a vehicle repair shop, sited next to the university president office building. The university has a plan to develop this location to be an â&#x20AC;&#x153;Energy Parkâ&#x20AC;? purposed to promote an innovation of energy saving and renewable energy using within the campus as well. To renovate this building to be a Net Zero Energy Building will be another project following the goal of the green and smart university. Furthermore, the building will be a learning case study for students and community. The research aims to study a possibility to renovate the Energy Management and Innovation Office, Building and Facility Division office, Khon Kaen University, to be a net zero energy building. building.

The study uses photovoltaic solar-cell system as the source of renewable energy for the The renovation will base on the minimum change of the existing structure and building

form.

2. NET ZERO ENERGY BUILDING Ministry of Energy had Thailand 20 year Energy Efficiency Development Plan (2011-2030) aimed to increase the energy efficiency of the government and private buildings beyond the Building Energy Code (BEC) toward Net Zero Energy Building (NZEB) within 2030. The Zero Energy Building concept is the idea that buildings can meet all energy requirement from low-cost, locally available, nonpolluting, renewable sources (Torcellini et al., 2006). Medium and large scale, cost effective zero energy buildings are expected to be viable in the next 15-20 years. However, rapid building technology development and determined building owners and designers had made medium and large-scale buildings successful today. (Yimprayoon, 2016) The research study of the parking building in Khon Kaen University shows that the rooftop solar-cell can generate enough electricity for the energy use of the public space of the parking building in case that the building can reduce energy use by 10% (Reangseree and Boonyaputthipong, 2017).

3. RESEARCH METHODOLOGY The methodology of this study begins with the surveying and collecting the building configuration and the energy consumption. The information will be used for analyzing the energy saving solutions focusing on the renovation of building components and equipment. Furthermore, the energy consumption data of the building will be used for the calculation of renewable energy needs. 134

The Solar Photovoltaic Energy is selected for this study because Thailand has relatively Chumnan Boonyaputthipong

high levels of solar insolation which makes the panels efficient to use. (MacDonald, 2012) A number of solar-cell panels will be used for designing the suitable location on the building roof. The possibility of the renewable energy use and installation will make the conclusion of the study. (Figure 1)

Figure 1: Research Methodology Diagram.

4. THE BUILDING INFORMATION This building is previously used by the university vehicle repair and maintenance shop. After the university set up the new office, the Energy Management and Innovation Office, this building is selected to serve for its workplace and research facility. The building is located next to the university president building. Related to the university plan, this location will be developed to be an energy park to show one of the main policies of the university, green and smart campus. Furthermore, the opposite side of this building, there is the first net-zero energy building on the campus, the Communication Affairs Division building.

4.1 FLOOR PLANS The building of the Energy Management and Innovation Office is a two-storey building. The first floor includes office rooms, restrooms and shop space. The second floor is a mezzanine with the functions of offices, restroom and a meeting room. The shop space located on the first floor is an open two-storey height. (Figure 2)

Figure 2: Building Floor Plans.

*Corresponding authors (C.Boonyaputthipong). Tel/Fax: +66-81-8712385 E-mail: bchumn@kku.ac.th. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/133.pdf.

135

4.2 ELEVATIONS Building elevations (Fig.3-4) show that the north and south sides of the building have five big rolling shutters each. The top of the wall are metal louvers run around for natural ventilation. The west side of the building has one big rolling shutters and metal louvers on the top and masonry wall for the rest. The east elevation shows that there are wood frame glazing windows for each room. Most of the building walls are masonry with light colour painted.

Figure 3: North Side (Left) and East Side (Right)

Figure 4: Building elevations.

4.3 SECTION Building sections (Figure 5) show that the first floor has a 4.00 meters height from floor to floor while the height of the second floor is 3.00 meters.

The open space of the shop is 8.50

meters height. The total of the building height is 10.00 meters.

The metal sheet is the material of

the building roof. The roof insulation, 2 inches fiberglass, is installed for the meeting and office rooms only.

Figure 5: Building Sections. 136

Chumnan Boonyaputthipong

5. ENERGY CONSUMPTION From the five years data (Figure 6), it found that in 2011 the building consumed electrical energy of 40,160 Kilowatt-hour and the building consumed the electrical energy of 33,903.80 Kilowatt-hour in 2012. After connected the solar-cells on the parking roof to the building, it found that the building consumed the electrical energy of 18,880.88 Kilowatt-hour in 2013 and 19,953.25 Kilowatt-hour in 2014. However, during the mid of 2015, the shop is temporarily installed some machines for the rubber oil research, the electrical energy consumption increase to be 26,342.00 Kilowatt-hour in the year 2015. Kilowatt-hour 45,000.00 40,000.00 35,000.00 30,000.00 25,000.00 20,000.00 15,000.00 10,000.00 5,000.00 0.00 2011

2012

2013

2014

2015

Figure 6: Energy Consumption. Energy uses in this building can be separated to be air-conditioning, lighting, office equipment and shop equipment. The air-conditioning is the main energy use that consumes 51% of the energy use in the building. Lighting and shop equipment consume 19% and 21% while office equipment consume 9% of the total energy use in the building. (Figure 7) 21%

Air-condition 51% Lighting 19%

51% 19%

Office Equipments 9% Shop Equipments 21%

Figure 7: Energy use in the building.

6. ENERGY SAVING 6.1 SUN SHADING East side of the building is the main part of the building that needs the sun-shading because all air-conditioning areas are located on this side. There are glazing windows without sun-shading. Due to the low angle of the morning sun, the solution will be a slat covering glazing windows and wall. (Figure 8). *Corresponding authors (C.Boonyaputthipong). Tel/Fax: +66-81-8712385 E-mail: bchumn@kku.ac.th. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/133.pdf.

137

Figure 8: Sun shading on the east and north side.

6.2 INSULATION The main part of the building that needs insulation is the roof because the roof is directly exposed to sunlight all day (Pongsuwan, 2009). The previous renovation of this building the roof insulation is added for the office function. So, the roof insulation for the shop space will be reduced the heat getting through the indoor area and part of the office area during the daytime.

6.3 WINDOW All windows of the building are the old gazing ones with wood frame. Besides the heat pass through the glazing area, it is also air leak through the old wood frames as well. The solution will be changing all windows to be vinyl-frames with reflective glass because the vinyl-frame is a good insulation with less air leaking.

6.4 LIGHTING There are different types of light tubes in the building. They will be replaced with LED (Light Emitting Diode) which can save energy down significantly. LEDs have proven to be extremely effective due to their long lifespan and increased efficiency (Karmakar et al., 2016)

6.5 AIR-CONDITION Recently, all of the air-condition in this building are split-type system. From the case study of the office of Communication Affairs Division building, the net-zero energy building, it has been founded that VRF with cooling-path can save energy down as much as 20-30% (Soodphakdee et al., 2014). So, this solution will be used for this building as well.

7. RENEWABLE ENERGY In Thailand, renewable energy that is typically used in the building is solar-cell because the sun-light is available mostly all year round. Moreover, the technology of solar-cell is higher quality while its cost becomes lower and available widely in Thailand. The study used the energy consumption during the last three years. The record showed that the average of energy consumption is 21,735.38 Kilowatt-hour per year or 59.55 Kilowatt-hour per day. This base number will be used for the solar-cell panel calculation. The energy consumption of 59.55 Kilowatt-hour per day or 59,550 Watt-hour per day will be used in Equation (1). 138

Chumnan Boonyaputthipong

(1), Where PL = Electrical power need for one day Q : Sunlight power per day in Thailand = 4,000 Watt-hour/sq.m. A : Compensation for loss = 0.8 B : Heat loss compensation = 0.85 C : Inverter Efficiency = 0.85 â&#x20AC;&#x201C; 0.9 D : Normal light intensity = 1,000 Watt-hour/sq.m. So, Pcell = 59,550/( 4,000x0.8x0.85x0.85/1,000) = 25,756.92 Watt or 25.76 Kilowatt The 300 watt crystalline solar-cell panel is selected for the study. So, the number of solar panel for this building is 25,756.92/300 = 85.86 or 86 panels.

8. PHOTOVOLTAIC SOLAR PANELS INSTALLATION The building roof is the best part of the building for solar-cell installation. In Thailand, the solar panel is expected to face to the south side with the angle between 10o - 20 o (Altevogt, 2014). The building has an available area on the roof for the installation of 86 solar panels with service space between the panels. The incline metal frame is fixed to the existing roof structure for solar-cell attached. This solution is a simple and the low cost one. (Figure 9)

Figure 9: Roof plan (Left) and Section (Right) shows the Solar-cell installation. The grid connection is selected for the study to avoid using a battery for stalling energy. The university has an electrical station, so this grid-connection system is the good solution for managing energy use in case of solar-cell cannot generate enough energy for the building. Moreover, in case that the solar-cell produces energy more the building use, the energy can transfer to nearby building automatically.

9. CONCLUSION This study uses a simple process for renovation existing building to be a net zero energy building. The result shows that the Energy Management and Innovation Office, Building and *Corresponding authors (C.Boonyaputthipong). Tel/Fax: +66-81-8712385 E-mail: bchumn@kku.ac.th. ÂŠ2018 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 9 No.2 ISSN 2228-9860 eISSN 1906-9642. http://TUENGR.COM/V09/133.pdf.

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Facility Division office, Khon Kaen University, can be a net zero energy building by the installation of the 86 solar-cell panels on the roof.

The energy saving by improving the building element and

equipments is for confirming the possibility of this project. The in-depth calculation and detail design will be further worked on the next study. The research will be used as information for the future plan of the university.

10. ACKNOWLEDGEMENTS The research is funded by the Division of Research Administration, Khon Kaen University.

11. REFERENCES A. Karmakar, S. Das and A. Ghosh, 2016, Energy Efficient Lighting by Using LED Vs. T5 Technology, IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE), e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 11, Issue 2 Ver. I (Mar. – Apr. 2016), PP 47-48 C. Yimprayoon, 2016, Review Article: Zero Energy Building, Journal of Architectural /Planning Research and Studies (JARS) 13(2), Thammasat University, Bangkok, Thailand. D. Soodphakdee, T. Wongwuttanasatian and C.Boonyaputthipong, 2014, Development of Building Technology for Net Zero Energy Building in Thailand, Final Report, Khon Kaen University and The Energy Policy and Planning Office (EPPO) J. Altevogt, 2014, Photovoltaic Energy Introduction, ESMAP—SAR—EAP Renewable Energy Training, 23-25 April 2014, Thailand. P. Reangseree and C. Boonyaputthipong, 2017, Improvement of a Parking Building 1 Food and Service Center 4, Khon Kaen University, to be a Net Zero Energy Building, Proceeding, 4th Building Technology Alliance Conference on Energy and Environment, Faculty of Architecture, Khon Kaen University, Khon Kaen, Thailand. P. Torcellini, S. Pless, and M. Deru, 2006, Zero Energy Buildings: A Critical Look at the Definition, ACEEE Summer StudyPacific Grove, California, 14-18 August 2006. S. MacDonald, 2012, Solar Photovoltaic Energy in Thailand: An assessment of government support mechanisms, LSE Asia Research Centre (ARC) – Thailand Government Scholarship, 3rd August 2012 – 27th September 2012 S. Pongsuwan, 2009, The Miracle of Insulation in Hot-Humid Climate Building, International Journal of Renewable Energy, Vol. 4, No. 1, January 2009 W. Anusakdakul and P. Puthipairoj, 2016, Guidelines for Development of Net Zero Energy Buildings for Governmental Office Buildings, Proceeding, 3rd Building Technology Alliance Conference on Energy and Environment, Faculty of Architecture, Khon Kaen University, Khon Kaen, Thailand. Dr. Chumnan Boonyaputthipong is an Assistant Professor of the Faculty of Architecture, Khon Kaen University. He received his B.Arch. from Khon Kaen University in 1993. He continued his Master Degree and Ph.D. study at Illinois Institute of Technology, USA, where he obtained his M.Arch. and Ph.D.(Architecture). Dr. Boonyaputthipong held the position of Vice President for Infrastructures Affairs, Khon Kaen University between 2011-2015. Recently, he is the university president’s consultant for infrastructure, renewable energy and related topics. He currently interests involve in the research topic of sustainable and local green architecture.

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