Building envelope optimization in office buildings

Building Envelope Optimization in Office Buildings

DEENBANDHU CHHOTU RAM UNIVERSITY OF SCIENCE & TECHNOLOGY MURTHAL (SONEPAT) Department of Architecture Faculty of Architecture, Urban & Town Planning

Abstract This dissertation aims to establish optimum building aspect ratio and WWR of offices buildings from thermal performance point of view in different climatic zones of India. The effects of five different building aspect ratios (2:1, 1.5:1, 1:1, 1:1.5 & 1:2) and five WWR (20%, 30%, 40%, 50% & 60%) for office building in five climatic zone in India: Composite Climate, Hot & Dry Climate, Warm & Humid, Temperate Climate & Cold Climate. The eQuest software of Dept. of energy, USA is used for thermal analysis. The total energy consumption is compared for all five aspect ratios and WWR to arrive at the optimum performance. The envelope is delineated as per prescriptive U-vales for walls, roof and glass as given in the ECBC.

II

Structure of Presentation Chapter 1 Introduction

1.1

1.1 Problem Statement

1.1

1.2 Aim and Objectives

1.1

1.3 Scope of the works

1.2

1.4 Methodology

1.2

1.5 Significance

1.3

Chapter 2 Literature review

2.1

2.1 Introduction

2.1

2.2 Published / works (Building Envelope & Window Wall Ratio)

2.1

Chapter 3 Research Design

3.1

3.1 Introduction

3.1

3.2 Weather data for building energy modeling

3.1

3.3 Building Form

3.2

3.4 Building Envelope

3.2

3.5 Simulation Methodology

3.5

3.6 Energy Simulation Tool –eQUEST

3.6

3.6 Modeling and Simulation Process

3.7

3.7 Modeling Tables

3.8

III

Chapter 4 Building Simulation Processes

4.1

4.1 Introduction

4.1

4.2 Building Model 3D View

4.1

Chapter 5 Simulation Results & Analysis

5.1

5.1 Introduction

5.1

5.2 Simulation Result for Major Five Climate Zone in India

5.1

5.3 Overall Comparison of Simulation Result for Each Climate Zone in India

5.6

Chapter 6 Final Conclusions

6.1

6.1 Introduction

6.1

6.2 Result Review for Major Five Climate Zone in India

6.1

6.3 Future Development

6.4

References

R.1

III

Chapter 1 Introduction 1.1

Problem Statement

Nowadays decisions regarding geometry, orientation, materials and construction methods of a building are made all at a time in the architectural design, but thought is not always given to how those choices may affect the buildings ultimate energy usage and the effect they may have on climate change.

This dissertation aims to find the suitable building aspect ratio and WWR in five Climate Zones in India.

To reduce the energy consumption of the built environment. With the help of the following Parameters•

Building aspect ratio

•

India Climate Zones in India

•

Properties of Material used for building envelope

•

Orientation of Building

•

WWR (Window Wall Ratio)

1.2

Aim and Objectives

The aim of this dissertations to find out the effective / optimum of Energy Performance Index (EPI) by parametric simulation of an office building aspect ratio (2:1, 1.5:1, 1:1, 1:1.5 & 1:2), WWR (20%, 30%, 40%, 50% & 60%) and five Climate Zones in India.

•

To understand study the state of the art of energy consumption in office buildings

•

To understand the provision of ECBC, NBC and ASHRAE.

•

To areas energy performance parametric study changing Building Envelope, Orientation & WWR for five Climate Zones in India.

•

To compare energy performances of (EPI) different cases.

•

To optimize WWR & orientation for each climatic zone in India.

1.1

1.3

Scope of the works

•

Computer Simulation on eQuest energy Simulation software

•

Assumption for Building Form, aspect ratio of building, window design parametric, properties of Material use for envelop, LPD, Equipment Load & building footprint area

•

Only for air conditioned building

1.4

Methodology

In order various to study parameters that affects the building energy performance, the dissertation follows the methodology given in the flow chart •

Building aspect ratio (2:1, 1.5:1, 1:1, 1:1.5 & 1:2)

•

Orientation North - South

•

WWR (20%, 30%, 40%, 50% & 60%)

•

Climate Zones in India

•

ECBC Building Envelope

With the help of eQuest energy simulation software to Energy Performance Index for each case will be found and will analyses them with a graphical comparisons.

1.2

Figure 1.1: Methodology Analyses graphical comparison

1.5

Significance

With the help of overall analysis we are able to judge Energy Performance with the change of Building aspect ratio, WWR, ECBC Building Envelop and North-south orientation can make a comparison for each different climate zone in India form of Energy Performance Index.

This analysis will help to validate the statement – ‘Building aspect ratio, Orientation of N-S and WWR affects energy performance of the Building’ up to a certain limit.

1.3

Chapter 2 Literature review 2.1

Introduction

The chapter aims to present comprehensive literature review on the subject “Building Envelope Optimization in Office Buildings�. For this purpose international journals, conference Preceding’s, books, reports and other relevant literature have been referred.

2.2

Published / works (Building Envelope & Window Wall Ratio)

2.2.1

The Effects of Form and Orientation on Energy Performance of Residential Buildings in Ghana (Koranteng and Abaitey 2010)

The form and orientation of a building can have an effect on energy performance. The difficulty has been to find the most energy efficient form-aspect ratio. In this paper, a volume with differ-ent aspect ratios has been used to investigate the effect on energy performance (cooling load). The volume used is of the same construction and an hourly dynamic simulation programme was used for the analysis. It was evident that the square form was the most energy efficient whiles elongated forms used much energy. However, since spaces could warm up when oriented to-wards the east and west, the authors further recommend a detailed look into the function of spaces in design schemes and the use of simulation for design alternatives.

2.1

Table 2.1: Result of the Effects of Form and Orientation on Energy Performance of Residential Buildings in Ghana

Building Envelop WWR

The effect of windows, doors, roofing, etc on cooling load was avoided through the use of solid walls with the same None conductance for all building elements. The construction for the building elements is a 20cm monolithic wall with plasterblock-plaster composition having a solar absorptance value of 0.80 and conductance of 10.933 w/m²°C

Climate

Building Form

1:1.0 = 4.0 x 4.0 Kumasi, Ghana 1:1.5 = 3.26 x 4.89

1:2.0 = 2.8284 x 5.6568

1:2.5 = 2.5298 x 6.3245

1:3.0 = 2.3094 x 6.9282

Orientation

Outcome

North angles(°)

Cooling Lowest loads cooling -2 -1 (kWh.m a ) loads (%)

0/180 90/270,

102.07 102.18

0.11

45/225 135/315 0/180, 90/270,

103.17 101.61 105.55

1.08 3.87

45/225 135/315

105.62 107.41

3.94 5.70

0/180 90/270 45/225 135/315 0/180, 90/270 45/225 135/315

104.60 110.70 110.81 114.72 108.80 122.55 116.74 116.89

5.83 5.94 9.67 12.64 7.30 7.44

0/180 90/270 45/225 135/315

113.56 123.10 123.28 130.48

8.40 8.56 14.9 2.2

2.2.2

The Effect of Building Aspect Ratio on Energy Efficiency: A Case Study for Multi-Unit Residential Buildings in Canada (McKeen and Fung 2014)

This paper examines the energy consumption of varying aspect ratio in multi-unit residential buildings in Canadian cities. The aspect ratio of a building is one of the most important determinants of energy efficiency. It defines the building surface area by which heat is transferred between the interior and exterior environment. It also defines the amount of building area that is subject to solar gain. The extent to which this can be beneficial or detrimental depends on the aspect ratio and climate. This paper evaluates the relationship between the geometry of buildings and location to identify a design vernacular for energy-efficient designs across Canada Table 2.2: Model simulation geometry Shape of the Buildings

Building Profile:

A

B

B 90°θ

C

C 90°θ

D

D 90°θ

E

E 90°θ

F

F 90°θ

G

G 90°θ

Aspect Ratio (X:Y)

1:1

1.3:1

1:1.3

1.5:1

1.5:1

2:1

1:2

2.7:1

1:2.7

3.2:1

1:3.2

4.2:1

1:4.2

Dimensions X

24.5

28.0

21.4

30.0

20.0

35.0

17.1

40.0

15.0

44.0

13.6

50.0

12.0

Dimension Y

24.5

21.4

28.0

20.0

30.0

17.1

35.0

15.0

13.6

44.0

12.0

Wall Surface Area

2987

3011

3048

3176

3353

Glazing Area (% of exterior surface)

36%

36%

36%

36%

36%

Glazing Area

1075

1084

1097

1143

1207

South facing Surface Area

747

South Facing Surface (% of exterior surface)

25%

853

652

914

610

1067

521

40.0

1219

m m

3780

m2

36%

36%

-

1264

1361

m2

3511

457

50.0

Unit

1341

415

1524

366 m2

28%

22%

30%

20%

34%

16%

36%

14%

38%

12%

40%

10%

-

2.3

Table 2.3: Model simulation parameters

Table 2.4: Air infiltration rates

Envelope

Component

Description

Exterior Wall Aluminum and Glass Spandrel with batt insulation, metal frame

Roof

Built up roof, polyurethane insulation

Glazing

Floor: HVAC Component Terminal

Description Fan Coil Unit (four pipe) Heating Set Point: 20 °C

Cooling Plant

Centrifugal Hermetic Chiller Fuel Source: Electricity Boiler (natural draft) Fuel Source: Natural Gas

Ventilation:

7.5 L/s per person (~0.4 L/s per m2) Internal Load and Schedule

People Density: 200 m2/p Weekday Schedule:

50 Pa

ASHRAE “Leaky”

3.00

2.40

5 pa 0.510

0.6

ASHRAE “Average”

1.50

1.20

0.255

ASHRAE “Tight”

0.50

0.40

0.085

Average MURB in Canada

3.76

3.01

0.638

0.155

0.6

Selected for simulation

1.18

0.94

0.200

Table 2.5: Average annual heating and cooling degree days in Canadian cities (1971–2000)

-

0.3

0.1

-

Climatic Attributes Heating Degree Days Cooling Degree Days Climatic Region

Thermostat

Heating Plant Supply

75 Pa

Emissivity

0.364

Earth contact with insulated Ground Floor footings Double pane, Low emissivity with argon gas (Glass Type Code: 2642) Solar Heat Gain Coefficient.: 0.75, Solar Transmittance: 0.54 Concrete slab (150 mm)

Air Tightness Reference

U Value (W/m2K)

Infiltration Rate L/(s·m2) at

Vancouver

Calgary

Toronto

Montreal

Halifax

2926

4948

4066

4575

4367

44

44

252

235

104

wet, cool

dry, very cold

moderately wet, cold

moderately wet, cold

wet and cold

Cooling Set Point: 25.6 °C Autosized between 150 and 299 tons Coefficient of performance: 4.6 Autosized Efficiency: 80%

-

Equipment Load: 7.0 W/m2 Lighting Load: 10.8 W/m2 Return at: 4 PM Leave at: 9 AM

2.4

Unit

MW H) (GJ)

(GJ) %

(GJ) %

MW H) (GJ)

(GJ) % (GJ) %

MW H) (GJ)

(GJ) % (GJ) %

MW H) (GJ)

(GJ) % (GJ) %

MW H) (GJ)

(GJ) % (GJ) %

Table 2.6: Model simulation results: total annual energy consumption. REC, relative Shape of the Buildings

Building Profile: Aspect Ratio (X:Y)

G 90°θ 1:4.2

F 90°θ 1:3.2

E 90°θ

D 90°θ

C 90°θ

B 90°θ

A

B

1:2.7

1:2

1.5:1

1:1.3

1:1

1.3:1

C 1.5:1

D

E

F

2:1

2.7:1

3.2:1

G

Unit

4.2:1

Montreal Cooling Consumption

133.6 481.1

127.0 457.0

119.3 429.5

113.3 408.0

107.8 388.2

104.7 377.0

103.2 371.5

101.5 365.5

100.5 361.7

94.6 340.7

94.9 341.6

97.2 349.9

98.6 355.1

(MWH) (GJ)

Heating Consumption

1554

1461

1389

1315

1236

1213

1198

1188

1195

1243

1286

1355

1416

(GJ)

REC

29.7

21.9

15.9

9.8

3.2

1.2

0.0

-0.9

-0.2

3.7

7.3

13.1

18.2

%

Combined Energy Consumption

2035

1918

1818

1723

1624

1590

1569

1553

1557

1584

1628

1705

1771

(GJ)

REC

29.6

22.2

15.8

9.8

3.5

1.3

0.0

-1.0

-0.80

0.9

3.7

8.7

12.9

%

Vancouver Cooling Consumption

41.2 148.5

39.1 140.8

36.5 131.5

34.4 124.0

32.9 118.6

32.0 115.4

31.5 113.4

31.2 112.2

30.9 111.3

30.6 340.7

30.6 110.2

31.1 112.1

31.1 111.8

(MWH) (GJ)

Heating Consumption

911

836

775

722

672

659

641

637

637

637

664

746

793

(GJ)

42.1

30.4

20.8

12.6

4.8

2.7

0.0

-0.9

-0.7

-0.7

3.5

16.3

23.7

%

1060

977

907

846

791

775

775

749

748

774

807

858

905

(GJ)

REC Combined Energy Consumption REC Halifax Cooling Consumption

40.4

29.5

20.1

12.1

4.8

2.7

0.0

-0.7

-0.9

2.5

6.9

13.7

19.9

%

48.0 172.9

46.3 166.7

43.4 156.4

41.2 148.4

38.6 139.1

37.6 135.4

37.3 134.2

36.9 132.9

36.5 131.5

36.2 130.2

36.1 129.9

36.7 132.2

36.6 131.7

(MWH) (GJ)

Heating Consumption

1492

1381

1315

1236

1163

1139

1128

1120

1127

1171

1216

1282

1365

(GJ)

32.2

22.4

16.6

9.6

3.1

1.0

0.0

-0.7

-0.1

3.8

7.8

13.7

21.0

%

1665

1547

1471

1384

1302

1274

1262

1253

1259

1302

1346

1415

1496

(GJ)

REC Combined Energy Consumption REC Calgary Cooling Consumption

31.9

22.6

16.6

9.7

3.1

1.0

0.0

-0.7

-0.3

3.1

6.6

12.1

18.5

%

75.8 272.7

72.1 259.7

67.6 243.2

63.8 229.6

60.3 217.0

58.5 210.7

57.5 207.1

56.3 202.8

55.3 199.2

54.8 197.2

54.8 197.3

55.8 201.0

56.4 203.0

(MWH) (GJ)

Heating Consumption

1748

1534

1450

1366

1281

1254

1235

1221

1226

1270

1318

1387

1560

(GJ)

41.6

24.3

17.5

10.6

3.8

1.6

0.0

-1.1

-0.7

2.9

6.8

12.4

26.3

%

2021

1794

1694

1595

1498

1465

1442

1424

1425

1467

1516

1588

1763

(GJ)

REC Combined Energy Consumption REC Toronto Cooling Consumption

40.1

24.4

17.5

10.6

3.9

1.6

0.0

-1.2

-1.2

1.8

5.1

10.2

22.3

%

116.9 421.0

111.5 401.2

104.1 374.8

99.9 359.8

96.0 345.8

93.6 337.1

92.9 334.6

91.9 330.7

91.0 327.5

90.5 325.9

89.4 321.7

91.3 328.5

91.1 328.1

(MWH) (GJ)

Heating Consumption

1428

1302

1230

1157

1087

1063

1056

1048

1054

1100

1143

1211

1308

(GJ)

35.2

23.4

16.5

9.6

3.0

0.7

0.0

-0.8

-0.2

4.1

8.2

14.7

23.9

%

1849

1705

1604

1517

1433

1400

1391

1378

1381

1425

1464

1540

1636

(GJ)

33.0

22.6

15.4

9.1

3.0

0.7

0.0

-0.9

-0.6

2.5

5.3

10.7

17.6

%

REC Combined Energy Consumption REC

2.5

Chapter 3 Research Design 3.1

Introduction

The chapter aims to present comprehensive Research Design on the scope of the project with reference of the followings•

Energy Conservation Building Code (BEE 2007)

•

National Building Code (BIS 2005)

•

National Building Code Draft (BIS 2011)

•

Handbook of Fundamental - American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE 90.1.ip.2010)

The purpose of using above standards are, the Indian code with reference of Indian Climatic conditions for various climate zones. In this chapter we are defining all the parameter which affects energy performance for a building for which we can make a standard modelling by putting those values which will help us to prepare a base model to compare with the variables like Building Aspect Ratio, WWR & Orientation for various climatic zones. And can take other aspects with a specific value with specific purpose.

3.2

Weather data for building energy modeling

Building energy models have been carried out for four cities, which represent four major climate zones of India, namely: •

Delhi (Composite Climate)

•

Jaisalmer (Hot & Dry Climate)

•

Chennai (Warm & Humid Climate)

•

Bangalore (Temperate Climate)

•

Guwahati (Clod Climate)

3.1

3.3

Building Form

Air conditioned rectilinear office building with an aspect ratio1.

Building aspect ratio 2:1

–

Building Foot Print Area – 56.00m. X 28.00m. X 3.6 m.

2.

Building aspect ratio 1.5:1 –

Building Foot Print Area – 48.46m. X 32.30m. X 3.6 m.

3.

Building aspect ratio 1:1

–

Building Foot Print Area – 39.60m. X 39.60m. X 3.6 m.

4.

Building aspect ratio 1:1.5 –

Building Foot Print Area – 32.30m. X 48.46m. X 3.6 m.

5.

Building aspect ratio 1:2

Building Foot Print Area – 28.00m. X 56.00m. X 3.6 m.

•

Simulation for typical floor plan from a Mid-rise office building.

•

Window design is restricted to a rectangular shape and will be in uniform size.

•

Orientation

•

WWR

3.4

Building Envelope

–

The building envelope refers to the exterior façade, and is comprised of opaque components and fenestration systems. Opaque components include walls, roofs, slabs on grade (in touch with ground), basement walls, and opaque doors. Fenestration systems include windows, skylights, ventilators, and doors that are more than one-half glazed. The envelope protects the building’s interior and occupants from the weather conditions and shields them from other external factors e.g. noise, air pollution, etc.

3.2

Table 3.1: Table representing Opaque Wall Assembly U-Factor and Insulation R-value Requirements

Table 3.2: Table representing Roof Assembly U-Factor and Insulation R-value Requirements Other Building Types (Daytime)

Other Building Types (Daytime) Maximum U-factor of the overall assembly (W/m2·K)

Minimum R-value of insulation alone (m2·K/W)

Composite

U-0.440

R-2.10

Hot and Dry

U-0.440

R-2.10

Warm and Humid

U-0.440

R-2.10

Moderate

U-0.440

R-2.10

Cold

U-0.352

R-2.35

Climate Zone

Composite Hot and Dry Warm and Humid Moderate Cold

Table 3.3: Table representing Vertical Fenestration U-factor (W/m2•K) and SHGC Requirements Climate Composite Hot and Dry Warm and Humid Moderate Cold

Maximum U-factor 3.3 3.3 3.3 6.9 3.3

WWR≤40% Maximum SHGC 0.25 0.25 0.25 0.4 0.51

Table 3.5: Table representing HVAC Systems Category

Nonresidential

Area & Nos. of Floor

4 or 5 floors or less than 7,500 m² or 5 floors or less and 7,500–15,000 m²

Code

RHFS

System type

Central cooling plant with constant volume AHU for each zone

Fan control

Constant volume air handler for each zone

Cooling type

Chilled water

Heating type

Electric resistance

Table 3.7: Table representing Interior Lighting Power- Building Area Method Building Area Type Office

LPD (W/m2) 10.8

Maximum U-factor of the overall assembly (W/m2·K) U-0.409 U-0.409 U-0.409 U-0.409 U-0.409

Climate Zone

Minimum R-value of insulation alone (m2·K/W) R-2.1 R-2.1 R-2.1 R-2.1 R-2.1

Table 3.4: Table representing Minimum Visual Light Transmission Light Transmission Requirements 40% <WWR≤60% Maximum SHGC 0.2 0.2 0.2 0.3 0.51

Window Wall Ratio

Minimum VLT

0 - 0.3

0.27

0.31-0.4

0.2

0.41-0.5

0.16

0.51-0.6

0.13

Table 3.6: Table representing Suggested Chiller Specifications (ECBC-2007, HVAC) Equipment Class *Centrifugal Water Cooled Chiller < 530 W (<150 tons)

Minimum COP 5.8

Minimum IPLV 6.09

Test Standard ARI 550/590-1998

Table 3.8: Table representing Acceptable Occupant Densities, Receptacle Power Densities, and Service Hot Water Consumption

Building Type

Occupancy Density Sq.Ft./Person (Btu/h . ft2)

Receptacle Power Density Watts/Sq.Ft. (Btu/h . ft2)

Service Hot Water Quantities Btu/h.

Person

Office 275 (0.84) 0.75 (2.56) 175  The occupancy densities, receptacle power densities, and service hot water consumption values are from ASHRAE Standard 90.1-1989 and addenda.  Values are in square feet of conditioned floor area per person. Heat generation in Btu per person per hour is 230 sensible and 190 latent. Figures in parenthesis are equivalent Btu per hour per square foot.  Values are in Watts per square foot of conditioned floor area. Figures in parenthesis are equivalent Btu per hour per square foot. These values are the minimum acceptable. If other  Process loads are not input (such as for computers, cooking, refrigeration, etc.), it is recommended that receptacle power densities be increased until total process energy consumption is equivalent to 25% of the total.  Values are in Btu per person per hour.

3.3

Table 3.9: Table representing Office Occupancy ASHRAE Specified Schedule for Office Building

Hour of Day (Time)

Schedule for Occupancy Percent of Maximum Load

Schedule for Lighting Receptacle Percent of Maximum Load

Schedule for HVAC System

Schedule for Service Hot Water Percent of Maximum Load

Schedule for Elevator Percent of Maximum Load

Wk

Sat

Sun

Wk

Sat

Sun

Wk

Sat

Sun

Wk

Sat

Sun

Wk

Sat

Sun

1 (12-1 am)

0

0

0

5

5

5

Off

Off

Off

5

5

4

0

0

0

2 (1-2 am)

0

0

0

5

5

5

Off

Off

Off

5

5

4

0

0

0

3 (2-3 am)

0

0

0

5

5

5

Off

Off

Off

5

5

4

0

0

0

4 (3-4 am)

0

0

0

5

5

5

Off

Off

Off

5

5

4

0

0

0

5 (4-5 am)

0

0

0

5

5

5

Off

Off

Off

5

5

4

0

0

0

6 (5-6 am)

0

0

0

10

5

5

Off

Off

Off

8

8

7

0

0

0

7 (6-7 am)

10

10

5

10

10

5

On

On

Off

7

7

4

0

0

0

8 (7-8 am)

20

10

5

30

10

5

On

On

Off

19

11

4

35

16

0

9 (8-9 am)

95

30

5

90

30

5

On

On

Off

35

15

4

69

14

0

10 (9-10 am)

95

30

5

90

30

5

On

On

Off

38

21

4

43

21

0

11 (10-11 am)

95

30

5

90

30

5

On

On

Off

39

19

4

37

18

0

12 (11-12 pm)

95

30

5

90

30

5

On

On

Off

47

23

6

43

25

0

13 (12-1 pm)

50

10

5

80

15

5

On

On

Off

57

20

6

58

21

0

14 (1-2 pm)

95

10

5

90

15

5

On

On

Off

54

19

9

48

13

0

15 (2-3 pm)

95

10

5

90

15

5

On

On

Off

34

15

6

37

8

0

16 (3-4 pm)

95

10

5

90

15

5

On

On

Off

33

12

4

37

4

0

17 (4-5 pm)

95

10

5

90

15

5

On

On

Off

44

14

4

46

5

0

18 (5-6 pm)

30

5

5

50

5

5

On

On

Off

26

7

4

62

6

0

19 (6-7 pm)

10

5

0

30

5

5

On

Off

Off

21

7

4

20

0

0

20 (7-8 pm)

10

0

0

30

5

5

On

Off

Off

15

7

4

12

0

0

21 (8-9 pm)

10

0

0

20

5

5

On

Off

Off

17

7

4

4

0

0

22 (9-10 pm)

10

0

0

20

5

5

On

Off

Off

8

9

7

4

0

0

23 (10-11 pm)

5

0

0

10

5

5

Off

Off

Off

5

5

4

0

0

0

24 (11-12 am)

5

0

0

5

5

5

Off

Off

Off

5

5

4

0

0

0

920

200

60

1040

280

120

1600

1200

0

537

256

113

555

151

0

Total/Day Total/Week

48.60 hours

56.00 hours

92.00 hours

30.54 hours

29.26 hours

Total/Year 2534 hours 2920 hours 4797 hours 1592 hours 1526 hours Wk = Weekday Schedules for occupancy, lighting, receptacle, HVAC system, and service hot water are from ASHRAE Standard 90.1-1989 and addendums, except that 5% emergency lighting has been added for all off hours. Elevator schedules, except for restaurants, are from the U.S. Department of Energy Standard Evaluation Techniques except changed to 0% when occupancy is 0%.These values may be used only if actual schedules are not known.

3.4

3.5

Simulation Methodology

Energy modeling software consists of a thermal calculation engine to predict the annual energy use of the building. As shown in Figure 3.1, building description defines the building geometry, layout, constructions, operating schedules, internal loads, HVAC systems, and local weather data. The simulation manager then performs an hourly simulation by calculating the building loads and the system requirements to meet the desired building conditions. The purpose of using above standards are, the Indian code with reference of Indian Climatic conditions for various climate zones. In this chapter we are defining all the parameter which affects energy performance for a building for which we can make a standard modelling by putting those values which will help us to prepare a base model to compare with the variables like Building Aspect Ratio, WWR & Orientation for various climatic zones. And can take other aspects with a specific value with specific purpose.

Figure 3.1: Diagram of Energy Modeling Loads 3.5

3.6

Energy Simulation Tool – eQUEST

eQUEST uses the DOE 2.2 Building energy simulation engine. It has the ability to explicitly model all of the following: •

8,760 hours per year

•

Hourly variations in occupancy, lighting power, miscellaneous equipment power, thermostat set-points, and HVAC system operation, defined separately for each day of the week and holidays

•

Thermal mass effects

•

Part-load performance curves for mechanical Equipment

•

Capacity and efficiency correction curves for mechanical heating and cooling equipment

eQUEST was designed to allow you to perform detailed analysis of today’s state-of-the-art building design technologies using today’s most sophisticated building energy use simulation techniques but without requiring extensive experience in the "art" of building performance modeling

It is supported as a part of the Energy Design Resources program which is funded by California utility customers and administered by Pacific Gas and Electric Company, San Diego Gas & Electric, and Southern California Edison, under the auspices of the California Public Utilities Commission. The basecase building is simulated with actual orientation and again after rotating the entire Building by 90, 180 & 270 Degrees and then averaging the results to get the Base-case Energy consumption.

Figure 3.2: eQUEST Logo

3.6

3.6

Modeling and Simulation Process

Each of the envelope and equipment efficiency cases was then simulated twice, once with no appliances and once with the use of appliances. This was done to understand the variation in energy consumption (appliances and AC) due to the appliancesâ&#x20AC;&#x2122; loads. The policy impacts and penetration of ECBC under various projection scenarios has been explained in the methodology of future projections.

The following figure shows the building energy modelling run chart for the study: Building aspect ratio

Figure 3.3: Building Energy Modelling Run chart 3.7

3.7

Modeling Tables

3.7.1

Model Case - 1 (Composite Climate) - New Delhi Parameters

Value

Parameters

Value

Location- New Delhi

3.7.2

Model Case - 2 (Hot & Dry Climate) – Jaisalmer Parameters

Area (Sq.ft)

Table 3.10: Model Description for Composite Climate (New Delhi) Latitude

28°32'17.76"N

Longitude

77° 9'12.07"E

Elevation (ft.)

Composite Model Geometry

Building aspect ratio Dimension (ft.)

2:1 = 184’ x 92’ 1.5:1 = 159’ x 106’ 1:1 = 130’ x 130’ 1:1.5 = 106’ x 159’ 1:2 = 92’ x 184’

Floor to floor height (m)

3.6

Number of floors

G+4

20%, 30%, 40%, 50% & 60% Envelop Materials

Roof U value (W/m 2-K) Wall U value

Building aspect ratio Total Conditioned Space

867

Climate Type

WWR

Building aspect ratio Floor plate Area

(W/m 2-K)

0.409

2:1 = 16928 1.5:1 = 16854 1:1 = 16900 1:1.5 = 16854 1:2 = 16928 2:1 = 84640 1.5:1 = 84270 1:1 = 84500 1:1.5 = 84270 1:2 = 84640

Frames, Doors & Dividers Material

Aluminum

Frame width (cm)

1.3

Value

Parameters

Location- Jaisalmer Area (Sq.ft) Table 3.11: Model Description for Hot & Dry Climate (Jaisalmar) Latitude

26°54'33.34"N

Building aspect ratio Floor plate Area

Longitude

70°54'38.01"E

Building aspect ratio Total Conditioned Space

Elevation (ft.)

817

Climate Type

Hot & Dry

Building aspect ratio Dimension(ft.)

N/S degree

Glazing Glass U value (W/m2-K)

3.30

Glass SHGC

0.25 & 0.20

Glass VLT

0.27, 0.20, 0.16 & 0.13

2:1 = 184’ x 92’ 1.5:1 = 159’ x 106’ 1:1 = 130’ x 130’ 1:1.5 = 106’ x 159’ 1:2 = 92’ x 184’

Floor to floor height (m)

3.6

Number of floors

G+4

WWR

20%, 30%, 40%, 50% & 60% Envelop Materials

Roof U value (W/m 2-K)

0.409

Wall U value (W/m 2-K)

0.440

HVAC System

Material

Aluminum

Frame width (cm)

1.3

Orientation

N/S degree Glazing

Glass U value (W/m2-K)

0.25 & 0.20

Glass SHGC

0.27, 0.20, 0.16 & 0.13 0.13

Glass VLT

Internal Loads

Central cooling plant with constant volume AHU

Lighting (W/sq. m)

Equipment (W/sq. m)

7.5

Chiller COP

Constant volume air handler for each floor 5.8

Occupancy (sq. m/person)

14

Cooling type Heating type

Chilled water Electric Resistance

Fan Control

2:1 = 84640 1.5:1 = 84270 1:1 = 84500 1:1.5 = 84270 1:2 = 84640

0.440 Internal Loads

System Type

2:1 = 16928 1.5:1 = 16854 1:1 = 16900 1:1.5 = 16854 1:2 = 16928

Frames, Doors & Dividers

Model Geometry

Orientation

Value

10.8 System Type

Fan Control

HVAC System Central cooling plant with constant volume AHU

Chiller COP

Constant volume air handler for each floor 5.8

Cooling type Heating type

Chilled water Electric Resistance

Lighting (W/sq. m)

10.8

Equipment (W/sq. m)

7.5

Occupancy (sq. m/person)

14

3.8

3.7.3

Model Case - 3 (Warm & Humid) - Chennai

3.7.4

Model Case - 4 (Temperate Climate) – Bangalore

Table 3.12: Model Description for Warm & Humid (Chennai) Parameters

Value

Parameters

Location- Chennai

Value

12°58'47.46"N

Building aspect ratio Floor plate Area

Longitude

80°15'1.26"E

Building aspect ratio Total Conditioned Space

23

Climate Type

Warm & Humid Model Geometry

Building aspect ratio Dimension(ft.)

2:1 = 184’ x 92’ 1.5:1 = 159’ x 106’ 1:1 = 130’ x 130’ 1:1.5 = 106’ x 159’ 1:2 = 92’ x 184’

Floor to floor height (m)

3.6

Number of floors

G+4

WWR

20%, 30%, 40%, 50% & 60% Envelop Materials

Roof U value (W/m 2-K)

0.409

Wall U value (W/m 2-K)

0.440

Parameters

Area (Sq.ft)

Latitude

Elevation (ft.)

Table 3.13: Model Description for Temperate Climate (Bangalore)

2:1 = 16928 1.5:1 = 16854 1:1 = 16900 1:1.5 = 16854 1:2 = 16928 2:1 = 84640 1.5:1 = 84270 1:1 = 84500 1:1.5 = 84270 1:2 = 84640

Frames, Doors & Dividers Material

Aluminum

Frame width (cm)

1.3

Value

N/S degree Glazing

Glass U value (W/m2-K)

3.30

Glass SHGC

0.25 & 0.20

Glass VLT

0.27, 0.20, 0.16 & 0.13

Area (Sq.ft)

HVAC System Central cooling plant with constant volume AHU

12°57'45.01"N

Building aspect ratio Floor plate Area

Longitude

77°34'37.47"E

Building aspect ratio Total Conditioned Space

Elevation (ft.)

2970

Climate Type

Temperate Climate Model Geometry 2:1 = 184’ x 92’ 1.5:1 = 159’ x 106’ 1:1 = 130’ x 130’ 1:1.5 = 106’ x 159’ 1:2 = 92’ x 184’

Floor to floor height (m)

3.6

Number of floors

G+4

WWR

20%, 30%, 40%, 50% & 60% Envelop Materials

Roof U value (W/m 2-K)

0.409

Wall U value (W/m 2-K)

0.440

10.8

System Type

Fan Control

Constant volume air handler for each floor

Equipment (W/sq. m)

7.5

Chiller COP

5.8

Occupancy (sq. m/person)

14

Cooling type Heating type

Chilled water Electric Resistance

2:1 = 84640 1.5:1 = 84270 1:1 = 84500 1:1.5 = 84270 1:2 = 84640

Frames, Doors & Dividers Material

Aluminum

Frame width (cm)

1.3

Orientation

N/S degree Glazing

Glass U value (W/m2-K)

6.90

Glass SHGC

0.40 & 0.30

Glass VLT

0.27, 0.20, 0.16 & 0.13 Internal Loads

Lighting (W/sq. m)

Fan Control

2:1 = 16928 1.5:1 = 16854 1:1 = 16900 1:1.5 = 16854 1:2 = 16928

Latitude

Internal Loads System Type

Value

Location- Bangalore

Building aspect ratio Dimension(ft.)

Orientation

Parameters

HVAC System Central cooling plant with constant volume AHU

Lighting (W/sq. m)

10.8

Constant volume air handler for each floor

Equipment (W/sq. m)

7.5

Chiller COP

5.8

Occupancy (sq. m/person)

14

Cooling type Heating type

Chilled water Electric Resistance

3.9

3.7.5

Model Case - 5 (Cold Climate) - Guwahati Table 3.12: Model Description for Cold Climate (Guwahati) Parameters

Value

Parameters

Value

Location- Guwahati

Area (Sq.ft)

Latitude

26° 7'33.55"N

Building aspect ratio Floor plate Area

Longitude

91°44'51.82"E

Building aspect ratio Total Conditioned Space

Elevation (ft.)

179

Climate Type

Composite Model Geometry

Building aspect ratio Dimension(ft.)

2:1 = 184’ x 92’ 1.5:1 = 159’ x 106’ 1:1 = 130’ x 130’ 1:1.5 = 106’ x 159’ 1:2 = 92’ x 184’

Floor to floor height (m)

3.6

Number of floors

G+4

WWR

20%, 30%, 40%, 50% & 60%

Envelop Materials Roof U value (W/m 2-K) 0.409 Wall U value (W/m 2-K)

2:1 = 16928 1.5:1 = 16854 1:1 = 16900 1:1.5 = 16854 1:2 = 16928 2:1 = 84640 1.5:1 = 84270 1:1 = 84500 1:1.5 = 84270 1:2 = 84640

Frames, Doors & Dividers Material

Aluminum

Frame width (in.)

1.3

Orientation

N/S degree Glazing

Glass U value (W/m2-K)

3.30

Glass SHGC Glass VLT

0.51 0.27, 0.20, 0.16 & 0.13

0.352 Internal Loads

System Type

HVAC System Central cooling plant with constant volume AHU

Lighting (W/sq. m)

10.8

Fan Control

Constant volume air handler for each floor

Equipment (W/sq. m)

7.5

Chiller COP

5.8

Occupancy (sq. m/person)

14

Cooling type Heating type

Chilled water Electric Resistance

3.10

Chapter 4 Building Simulation Processes 4.1

Introduction

The chapter aims to present comprehensive Building Model 3D View of the various Building aspect ratio and WWR Snapshots on the subject â&#x20AC;&#x153;Building Envelope Optimization in Office Buildingsâ&#x20AC;?.

4.2

Building Model 3D View

Figure 4.1: Building Model 3D View at Building aspect ratio of 2:1 & 20% WWR

Figure 4.2: Building Model 3D View at Building aspect ratio of 1.5:1 & 30% WWR

4.1

Figure 4.3: Building Model 3D View at Building aspect ratio of 1:1 & 40% WWR

Figure 4.4: Building Model 3D View at Building aspect ratio of 1:1.5 & 50% WWR

Figure 4.4: Building Model 3D View at Building aspect ratio of 1:2 & 60% WWR

4.1

Chapter 5 Simulation Results & Analysis 5.1

Introduction

The chapter aims to present comprehensive Simulation Results & Analysis on the subject “Building Envelope Optimization in Office Buildings”.

5.2

Simulation Result for Major Five Climate Zone in India

5.2.1

Simulation Result New Delhi

Table 5.1: Simulation Result for (Composite Climate) - New Delhi (in E.P.I.) Climate Zone

Composite Climate

Building aspect ratio City

Orientation

New Delhi

N.S

WWR 2:1

1.5:1

1:1

1:1.5

1:2

20%

100.95

100.35

100.72

102.04

102.37

30%

100.84

101.11

101.17

101.88

102.64

40%

110.54

110.53

111.06

111.66

112.54

50%

112.21

111.95

111.75

113.1

114.29

60%

109.73

109.67

110.37

111.51

112.36

Max.

Min.

% saving

114.29

100.35

12.20%

Max. Energy Consumption = 114.29 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR) Min. Energy Consumption = 100.35 kWh/sq.m./year (At Building aspect ratio of 1.5:1 & 20% WWR)

ENERGY PERFORMANCE INDEX( KWH/SQ.M./YEAR)

Envelope Performance (Composite Climate) - New Delhi 120 115 110 105 100 95 90 2:1

1.5:1

1:1

1:1.5

1:2

BUILDING ASPECT RATIO WWR 20%

WWR 30%

WWR 40%

WWR 50%

WWR 60%

Figure 5.1: Envelop performance graph for (Composite Climate) - New Delhi (in E.P.I.)

5.1

5.2.2

Simulation Result Jaisalmer

Table 5.2: Simulation Result for (Hot & Dry Climate) – Jaisalmer (in E.P.I.) Climate Zone

Hot & Dry Climate

Building aspect ratio City

Orientation

Jaisalmer

N.S

WWR 2:1

1.5:1

1:1

1:1.5

1:2

20%

103.28

102.65

102.98

104.44

104.87

30%

103.21

103.47

103.48

104.28

105.19

40%

112.69

112.69

113.24

113.88

114.84

50%

114.34

114.04

113.88

115.31

116.49

60%

112.06

112.00

112.73

114.03

114.85

Max.

Min.

% saving

116.49

102.65

11.88%

Max. Energy Consumption = 116.49 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR)

Min. Energy Consumption = 102.65 kWh/sq.m./year (At Building aspect ratio of 1.5:1 & 20% WWR)

ENERGY PERFORMANCE INDEX( KWH/SQ.M./YEAR)

Envelope Performance (Hot & Dry Climate) - Jaisalmer 120 115 110 105 100

95 2:1

1.5:1

1:1

1:1.5

1:2

BUILDING ASPECT RATIO WWR 20%

WWR 30%

WWR 40%

WWR 50%

WWR 60%

Figure 5.2: Envelop performance graph for (Hot & Dry Climate) – Jaisalmer (in E.P.I.)

5.2

5.2.3

Simulation Result Chennai

Table 5.3: Simulation Result for (Warm & Humid) - Chennai (in E.P.I.) Climate Zone

Warm & Humid Climate

Building aspect ratio City

Orientation

Chennai

WWR

N.S

2:1

1.5:1

1:1

1:1.5

1:2

20%

108.72

108.51

108.55

108.92

108.84

30%

107.30

107.47

107.37

107.62

107.81

40%

116.46

116.27

116.56

116.92

117.62

50%

117.80

117.43

117.04

118.03

118.97

60%

114.86

114.67

114.91

115.59

116.24

Max.

Min.

% saving

118.97

107.37

9.75%

Max. Energy Consumption = 118.97 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR)

Min. Energy Consumption = 107.37 kWh/sq.m./year (At Building aspect ratio of 1:1 & 30% WWR)

ENERGY PERFORMANCE INDEX( KWH/SQ.M./YEAR)

Envelope Performance (Warm & Humid Climate) - Chennai 120

115 110 105 100 2:1

1.5:1

1:1

1:1.5

1:2

BUILDING ASPECT RATIO WWR 20%

WWR 30%

WWR 40%

WWR 50%

WWR 60%

Figure 5.3: Envelop performance graph for (Warm & Humid) Chennai (in E.P.I.)

5.3

5.2.4

Simulation Result Bangalore

Table 5.4: Simulation Result for (Temperate Climate) – Bangalore (in E.P.I.) Climate Zone

Temperate Climate

Building aspect ratio

City

Orientation

Bangalore

N.S

WWR 2:1

1.5:1

1:1

1:1.5

1:2

20%

95.19

95.06

95.22

95.90

95.81

30%

92.88

93.11

93.10

93.42

93.63

40%

99.72

99.75

99.97

100.47

101.37

50%

99.20

99.12

99.10

99.99

100.96

60%

98.94

96.01

96.63

97.39

98.02

Max.

Min.

% saving

101.37

92.88

8.38%

Max. Energy Consumption = 101.37 kWh/sq.m./year (At Building aspect ratio of 1:2 & 40% WWR)

Min. Energy Consumption = 92.88 kWh/sq.m./year (At Building aspect ratio of 2:1 & 30% WWR)

ENERGY PERFORMANCE INDEX( KWH/SQ.M./YEAR)

Envelope Performance (Temperate Climate) – Bangalore 104 102 100 98 96 94 92 90 88 2:1

1.5:1

1:1

1:1.5

1:2

BUILDING ASPECT RATIO WWR 20%

WWR 30%

WWR 40%

WWR 50%

WWR 60%

Figure 5.4: Envelop performance graph for (Temperate Climate) – Bangalore (in E.P.I.)

5.4

5.2.5

Simulation Result Guwahati

Table 5.5: Simulation Result for (Cold Climate) - Guwahati (in E.P.I.) Climate Zone

Cold Climate

Building aspect ratio City

Orientation

Guwahati

N.S

WWR 2:1

1.5:1

1:1

1:1.5

1:2

20%

100.74

100.62

100.72

101.17

101.08

30%

99.92

100.10

100.12

100.28

100.74

40%

109.91

109.83

110.22

110.77

111.98

50%

114.01

113.52

113.34

115.21

116.82

60%

112.38

112.40

112.84

114.45

115.81

Max.

Min.

% saving

116.82

99.92

14.47%

Max. Energy Consumption = 116.82 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR)

Min. Energy Consumption = 92.92 kWh/sq.m./year (At Building aspect ratio of 2:1 & 30% WWR)

ENERGY PERFORMANCE INDEX( KWH/SQ.M./YEAR)

Envelope Performance (Cold Climate) Guwahati 120 115

110 105 100

95 90 2:1

1.5:1

1:1

1:1.5

1:2

BUILDING ASPECT RATIO WWR 20%

WWR 30%

WWR 40%

WWR 50%

WWR 60%

Figure 5.5: Envelop performance graph for (Cold Climate) Guwahati (in E.P.I.)

5.5

5.3

Overall Comparison of Simulation Result for Each Climate Zone in India

Table 5.6: Overall Comparison of Simulation result for each climate zone Building aspect ratio City

Composite New Delhi Climate

Orientation

N.S

WWR 2:1

1.5:1

1:1

1:1.5

1:2

20%

100.95

100.35

100.72

102.04

102.37

30%

100.84

101.11

101.17

101.88

102.64

40%

110.54

110.53

111.06

111.66

112.54

50%

112.21

111.95

111.75

113.1

114.29

60%

109.73

109.67

110.37

111.51

112.36

20%

103.28

102.65

102.98

104.44

104.87

30% Hot & Dry Jaisalmer Climate

Warm & Humid Climate

Chennai

Temperate Bangalore Climate

Cold Climate

Guwahati

N.S

N.S

N.S

N.S

40%

103.21

112.69

103.47

112.69

103.48

113.24

104.28

113.88

Max.

Min.

% saving

114.29

100.35

12.20%

% Savings Potential for each Climate Zone

105.19

114.84

50%

114.34

114.04

113.88

115.31

116.49

60%

112.06

112.00

112.73

114.03

114.85

20%

108.72

108.51

108.55

108.92

108.84

30%

107.30

107.47

107.37

107.62

107.81

40%

116.46

116.27

116.56

116.92

117.62

50%

117.80

117.43

117.04

118.03

118.97

60%

114.86

114.67

114.91

115.59

116.24

20%

95.19

95.06

95.22

95.9

95.81

30%

92.88

93.11

93.10

93.42

93.63

40%

99.72

99.75

99.97

100.47

101.37

50%

99.20

99.12

99.10

99.99

100.96

60%

98.94

96.01

96.63

97.39

98.02

20%

100.74

100.62

100.72

101.17

101.08

30%

99.92

100.10

100.12

100.28

100.74

40%

109.91

109.83

110.22

110.77

111.98

50%

114.01

113.52

113.34

115.21

116.82

60%

112.38

112.40

112.84

114.45

115.81

116.49

118.97

102.65

107.37

11.88%

9.75%

SAVING % BETWEEN LOWEST & HIGHEST ENERGY E.P.I.

Climate Zone

16 14

14.47 12.2

12

11.88 9.75

10

8.38

8

6 4 2 0 New Delhi

Jaisalmer

Chennai

Bangalore

Guwahati

MAJOR CLIMATE CITY IN INDIA

Figure 5.6: % Savings Potential for each Climate Zone in India 101.37

92.88

8.38%

116.82

99.92

14.47%

5.6

Chapter 6 Final Conclusions 6.1

Introduction

The chapter aims to present comprehensive Final Conclusions on the subject “Building Envelope Optimization in Office Buildings”.

The next section presents the Result Review for Major Five Climate Zone in India and Final section presents the Future Development of the various Simulation Results & Analysis on the subject 6.2

Result Review for Major Five Climate Zone in India

6.2.1

Result Review New Delhi

•

True North-South orientation is the best orientation

•

By increasing WWR energy consumption is also increasing due to more heat gain in to the building through window.

•

Max. Energy Consumption = 114.29 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR)

•

Min. Energy Consumption = 100.35 kWh/sq.m./year (At Building aspect ratio of 1.5:1 & 20% WWR)

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In New Delhi, as per our results building aspect ratio 1.5:1 leads to least consumption among the other counterparts. But the pattern is consistent in 20% WWR case only.

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We can reduce 12.20% energy consumption by using at Building aspect ratio, WWR and orientation of North /South for New Delhi.

6.1

6.2.2

Result Review Jaisalmer

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True North-South orientation is the best orientation

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By increasing WWR energy consumption is also increasing due to more heat gain in to the building through window.

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Max. Energy Consumption = 116.49 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR)

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Min. Energy Consumption = 102.65 kWh/sq.m./year (At Building aspect ratio of 1.5:1 & 20% WWR)

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In Jaisalmer, as per our results building aspect ratio 1.5:1 leads to least consumption among the other counterparts. But the pattern is consistent in 20% WWR case only.

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We can reduce 11.88% energy consumption by using at Building aspect ratio, WWR and orientation of North /South for Jaisalmer.

6.2.3

Result Review Chennai

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True North-South orientation is the best orientation

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By increasing WWR energy consumption is also increasing due to more heat gain in to the building through window.

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Max. Energy Consumption = 118.97 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR)

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Min. Energy Consumption = 107.37 kWh/sq.m./year (At Building aspect ratio of 1:1 & 30% WWR)

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In Chennai, as per our results building aspect ratio 1:1 and 30% WWR becomes most efficient design.

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We can reduce 9.75% energy consumption by using at Building aspect ratio, WWR and orientation of North /South for Chennai.

6.2

6.2.4

Result Review Bangalore

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True North-South orientation is the best orientation

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By increasing WWR energy consumption is also increasing due to more heat gain in to the building through window.

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Max. Energy Consumption = 101.37 kWh/sq.m./year (At Building aspect ratio of 1:2 & 40% WWR)

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Min. Energy Consumption = 92.88 kWh/sq.m./year (At Building aspect ratio of 2:1 & 30% WWR)

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In Bangalore, as per our results building aspect ratio 2:1 and 30% WWR becomes most efficient design.

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We can reduce 8.38 energy consumption by using at Building aspect ratio, WWR and orientation of North /South for Bangalore.

6.2.5

Result Review Guwahati

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True North-South orientation is the best orientation

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By increasing WWR energy consumption is also increasing due to more heat gain in to the building through window.

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Max. Energy Consumption = 116.82 kWh/sq.m./year (At Building aspect ratio of 1:2 & 50% WWR)

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Min. Energy Consumption = 92.92 kWh/sq.m./year (At Building aspect ratio of 2:1 & 30% WWR)

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In Guwahati, as per our results building aspect ratio 2:1 and 30% WWR becomes most efficient design.

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We can reduce 14.47% energy consumption by using at Building aspect ratio, WWR and orientation of North /South for Guwahati.

6.3

6.3

Future Development

In the India, the environmental burden of buildings represents a problem that need to be alleviated. In order to fulfill with international agreements and commitments, the Government of India will be forced to set new rules regarding building energy consumption. As a first step In order to comply with the new regulations, architects should develop their design techniques, adopt more environmental strategies and finally increase their knowledge about the environment and buildings. As each building will be provided with limited amount of energy, architects will be forced to change many design decisions, concepts, elements and materials.

On the other hand, mechanical and environmental engineers will have a major role in the design process as they will be studying how each decision architects take affects the building total energy consumption.

Therefore, in order to provide the architects with a holistic approach of reducing thermal energy consumption in office buildings located in different climates, Finally, more research should be done on achieving a balance between reducing energy by the passive techniques and the user's visual and acoustical comfort. If done, this research would help architects and designers in taking the proper environmental design decisions that achieve users comfort in the built environment.

6.4

References •

BEE (2005) National Building Code, Bureau of Indian Standard, New Delhi.

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Energy Conservation Building Code (2009). Bureau of Energy Efficiency.

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ASHRAE Standard (2010). American Society of Heating, Refrigerating, and Air-Conditioning Engineers.

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http://www.sciencedirect.com/

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http://www.researchgate.net/publication

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Koranteng, C. and Abaitey, E. G. (2010)."The Effects of Form and Orientation on Energy Performance of Residential Buildings in Ghana", Journal of Science and Technology, vol. 30, pp. 01, http://www.ajol.info/index.php/just/article/download/53940/42487.

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McKeen, P. and Fung, A. S. (2014)."The Effect of Building Aspect Ratio on Energy Efficiency: A Case Study for Multi-Unit Residential Buildings in Canada”, Building, vol. 04, pp. 336-354, http://www.mdpi.com/2075-5309/4/3/336.

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http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data2.cfm/region=2_asia _wmo_region_2

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http://www.doe2.com/equest/

R.1