Smithgall Student Service Building Energy Performance Evaluation and Retrofit From: Tianyu Feng (firstname.lastname@example.org) Submit to: prof. Augenbroe Godfried Arch. 6226 Green Construction Final Report Fall 2015
Contents Building and site introduction-------------------------------------------------------------------------------------------------------3 Site climatic condition analysis------------------------------------------------------------------------------------------------------5 Energy star target finder goal and normalization--------------------------------------------------------------------------------7 Energy Conservation Method 1- MEP features---------------------------------------------------------------------------------12 Energy Conservation Method II â€“ Architecture features--------------------------------------------------------------------- 14 Energy Conservation Method III â€“ Building operation features------------------------------------------------------------- 15 Cost analysis-------------------------------------------------------------------------------------------------------------------------- 16 Design optimization------------------------------------------------------------------------------------------------------------------ 21 Tech-opt optimization--------------------------------------------------------------------------------------------------------------- 25 Conclusion---------------------------------------------------------------------------------------------------------------------------- 33 Works Cited-------------------------------------------------------------------------------------------------------------------------- 35
Building and site introduction Smithgall student service building is located in the west east portion of Georgia Institute of Technology, Atlanta campus. It was built in 1990 by architect Johnson Smith Reagan with a steel and concrete structure. As an administrative building on campus, it provides 42,598 sq ft (3957 sq m) gross floor area, which includes 38,847 sq ft (3609 sq m) assigned office spaces for 14 departments and a three story tall open space for group gathering or lobby. In a regular situation, the assigned space could accommodate for 189 people to work and study (Spacemanagement). Sitting at the South-west portion of the campus, Smithgall building is in a relatively dense context and surrounded by student center parking lots, open lot visitor parking, Wenn student center, and Crest Art Center.
typical indoor hallway
As an office building serves every student, the Smithgall building has a nice Architectural gesture with a three-story tall â€œgreenhouseâ€? space at North-east corner, which responds well to the glass-box dinning space in student center. Structurally, it is independent from the whole building with its own concrete frame, which creates a contrast with the red bricks wall finish of rest of the building. Within this space, the architect tried to simulate a conditioned outdoor space by creating extra height with a massive pitched roof, installing the same outdoor lighting fixtures and pavement. As it moves toward the South-west direction, the building is closed up as regular two story buildings with traditional offices. When users enter the building, they could have a smooth spatial transition. Outside of this glass space, it is surrounded by plenty of trees to create a sense of being embraced by in nature, which also acts as shading and alleviate the solar radiative heat gain through huge area of the curtain walls. Department
Auxiliary Services, AVP
Center For The Arts, R. Ferst
Room/Space Count 9
Dean of Students
Leadership Education & Development Program Non-Assignable Parents Program
Student Government Assoc.
VPSA - Assessment
Student Affairs, VP
VPSS-Student Publications Vending TOTALS
38,847 Total Gross Floor Area
To create a sense of outdoor in the glass box space, the building faces a serious challenge in shading on East side and heat loss/gain throughout the massive glass surface. Although the space is surrounded by dense cluster of trees, the sufficiency of shading still need further proof. On South direction, there are no shading devices, and the windows are almost flushed with exterior finishes of the wall assembly, which have no shading effect to the glazing. Even worse, adjacent to a ground parking lot, there is no other sun light sun obstructions, which could potentially cause serious glare in the south office space. Although the west faรงade is usually in the worst situation, the extruded parking garage is only 6-8 feet away from the Smithgall building at the south west portion; it alleviates the glare issues on the west faรงade. The downside of it is the parking structure basically kills the view from the west side office. Also, the tree density along west side is very high and creates a lot of shading to this side. In the morning, most rooms need to open lights to satisfy certain lighting level. The east faรงade faces the student center with plenty of trees around this side. The 25 feet walk path means the two buildings has no shading effect to each other since both buildings are about 9 meters tall. Probably, new shading devices need to be introduces to avoid glare in the morning. Overall, due to a low height of the windows on the first floor, 90% of the windows are covered by the internal drips to private privacy. At the same time, people turn on the light throughout the whole day, which is a huge water of natural light and increase the energy consumption in terms of brighten the spaces.
Site climatic condition analysis
From left to right: January to June
From Lleft to right: July to December
The climate in Atlanta is 3a, which is humid and hot in the summer and humid and mild in winter, It makes the natural ventilation difficult during summer when the air contains high humidity (Passe, 2015). Based on the wind rose diagram, the monthly dominant wind direction mostly from North West direction and it is stronger and last longer during January to May and from October to December. It creates possible opportunities for natural ventilation during these seasons.View along with dry bulb and humidity diagrams, it further proves the feasibility of natural ventilation during these seasons when temperature is relatively mild and humidity is low (UCLA). Since the temperature and humidity fluctuates daily, an automated natural flush out plan can be embodied in the boiling to comply with indoor thermal comfort and maximize the efficiency of energy usage. Currently, there are some operable windows on west and east facade of the building, but it possibly doesnâ€™t work as effectively since the users donâ€™t operate these windows based on the temperature or humidity pattern, especially most of operable time is after office hours. Also, the building is quite bulky, and the whole faĂ§ade is occupied by offices. During after hour time when doors of each office are closed, the natural air flush out become fairly difficult.
Energy star target finder goal and normalization Based on the Ecotect Analysis, the shading reduction factor is shown as follows. 1 represents no shading at all, and 0 represents fully shaded. Here is a group of simulation smaples of west facade. All the scale is from 1(blue)-100 (orange).
The latest time of renovation on Smithgall building is in 2010, and the facility management replaced the HVAC system with variable air volume system and re-wire the lighting system. Besides it, the building maintains the original construction since 1990. Here are major factors of original input that influencing the energy consumption. 1. Building automation system The building is lack of automation system. The lighting is mostly out of control of users except for table light. Also, in many situations, the lights are always on even indoor space is fairly bright. Based on the employee in LGBTQT office description, the building lighting system doesn’t have dimming function. As a result, the illuminance couldn’t be adjust based the light level of natural light.The building doesn’t have the day lighting sensor either, and the lighting switch control is completely based on user pattern. With more than 50% office space compacted in the center without natural light access, it is quite redundant to have the daylight sensor. As a result, the illuminance couldn’t be adjust based the light level of natural light. Also, there is no occupant sensor in the building, which results in the light on all the time during operation hours.
COP of HVAC
The building has a relatively huge double pane without low E coating glazing area on the façade, which loses plenty of energy due to heat gain/loss. Currently, the HVAC system is a 5-year old VAV system, which is supposed to maintain a relatively high efficiency. There is no heating recovery system to maximize the energy usage. The whole building is fully mechanical ventilated. The employees in LGBTQIA office reports that although there are some small windows in some office, it rarely used unless the indoor space has wired ascent.
Building envelope information
The building has a relatively huge glazing area on the faĂ§ade, which loses plenty of energy due to heat gain/loss. Also, this part of the building hasnâ€™t been renovated since 1990. Based on the NERL report, U.S. Department of Energy Commercial Reference Building Models of the National Building Stock (NERL, 2011), the average U values of each component are show as the image bellows, and the data is about 10 times worse than the current advanced products.
4. Applicance and lighting Currently, the buidling is illuminaed by incandescent and fluorescent light, and it consumes about 10 W/m2 of energy per year to reach a 320 lux illuminance in office and 50 lux in corridor and circulation space. The Appliance information is estimated by the
occupancy load 189 people and chapter 3, Building energy data book (DOE). The appliance load currently is a gray area as the equipment is brought in during different time period and different model. Also, the unstable plug load could also be high. Here the assumption of this portion is 10 W/m2. 5. Occupancy activity This part is based on the U.S. Department of Energy Commercial Reference Building Models of the National Building Stock and my observation during different times throughout a month. During the weekends, the building is basically shut down, and nobody could entered unless their get permission with student/faculty ID.
Based on the monthly shading reduction factor and all the key factor input, we could calculation the current primary energy consumption of the building as 550.52 kwh/m2/ yr. As for the delivered energy of the building, it consumes 234.9 kwh/m2/ yr, which include 89 kwh/m2/ yr natural gas and 145.9 kwh/m2/ yr of electricity. EPC1 EPC2 ECP3 ECP4
Jan 17.840 49.520 73.670 14444.000
Feb 10.510 30.690 49.140 11672.000
Mar 3.770 13.080 29.750 6760.000
Apr 2.760 7.980 25.510 5617.000
May 7.520 11.780 35.980 8764.000
Jun 12.940 16.120 54.710 11993.000
Jul 15.230 18.860 61.280 13433.000
Aug 16.310 17.830 60.500 13263.000
Sep 7.900 11.930 46.100 8872.000
Oct 2.360 8.910 25.080 5582.000
Nov 5.110 17.300 33.410 6298.000
Dec 11.990 30.910 55.390 13172.000
TOTAL Total/ref. 114.240 1.503 234.910 1.894 550.520 2.284 119870.000 2.211
Energy star target finder become a prevailing measure of the energy consumption level of buildings and helps architects, engineers, and property owners and managers assess the energy performance of commercial building designs and existing buildings by giving us a quick-and-easy calculations and “what-if” scenario. With a scale of 1 – 100 ENERGY STAR score, it could give us amounts of energy consumption based on the score we plan achieve. To normalize the data, target finder is only calculating the EUI (Energy Usage Intensity) per square meet/feet by input location, gross floor area, building adjacency condition, occupancy load, major function, heating/cooling percentage, operation hours and the amount of appliances (Energy Star). However, due the difference calculation methods behind EPC and Energy star Target finder, we need to normalize the data first before we could apply the same data in both programs to compare the performance of the building. As the reference of EPC indicates that the average EPC3 (source EUI) of office building is 241 kwh/m2/ yr, which need to scale up to be comparable to Energy start target finder. In other words, the ration of energy consumption of certain level to the average consumption should be same no matter in target finder or EPC.
Currently the EPC 3 is [550.52 kwh/m2/ yr] / [241 kwh/m2/ yr] = 2.28 To reach the score 75, the primary energy need to reduce to 578 kwh/m2/ yr in Energy Target Finder. [578 kwh/m2/ yr] / [778 kwh/m2/ yr] = [ EPC 75 Normalized data] / [241 kwh/m2/ yr] EPC 75 Normalized data = 179.05 kwh/m2/ yr [179.05 kwh/m2/ yr] / [241 kwh/m2/ yr] = 0.74 To reach the score 90, the primary energy need to reduce to 431 kwh/m2/ yr in Energy Target Finder. [431 kwh/m2/ yr] / [778 kwh/m2/ yr] = [EPC 90 Normalized data] / [241 kwh/m2/ yr] ETF 90 Normalized data = 133.51 kwh/m2/ yr [133.51 kwh/m2/ yr] / [241 kwh/m2/ yr] = 0.55 Another crucial factor is EPC 2, which is 1.89 in this case. To clients, this number is mostly what make a difference since EPC 2 relates to the utilities bills and determine if the renovation could get pay back. Usually When EPC 2 reaches 1, it represent 30% better than the requirement of code. EPC 1
Energy Star 50
124 - 1
241 - 1
Energy Star 75
91.8 - 0.74
178.3 - 0.74
Energy Star 90
69.4 - 0.56
132.6 - 0.55
Energy Star 95
57 - 0.46
110.9 - 0.46
Energy Conservation Method 1- MEP features The first set of renovation concentrates on the mechanical system, including lighting bulb, ventilation fans and heat recovery system. As it is stated, the HVAC system of the building has been renovated and changed to Variable Air Volume system in 2010. In this section, the first step is to change the lighting bulbs. Currently the building uses traditional incandescent light bulbs in the glass box space and fluorescent light, which round up the energy intensity of lighting to 10 W/m2. In office space, the illuminance level requires 320-500 lux, and 50 lux for hallway or circulation space (Grondzik, 2010). To reach the same light density level of average 400 lux light level (400 lumens/m2), we need to replace current light bulbs with the same amount of LED bulbs with 4 W/m2 (Light comparion chart).
500 lumens/m2 * 3385 m2 (office area) = 1692750.9 lumens 50 lumens/m2 * 572 m2 (other area) = 28600 lumens (1692750.9 lumens + 28600 lumens)/3957 m2 = 435 lumens/m2 450 lumens/m2/4.5 W = 435/ actual watt actual watt = 4.35 W/ m2
Based on data from NERL (NERL), it could be replaced with the LED with the properties of Luminous Efficacy of 50.0 lm/W, and it meets Energy Star 2010 with life span of 42500 h. The second implement is to add a heat recovery system, specifically the heat exchange plates or pipes with 60% Exhaust air recirculation upon the current HVAC. It maximizes the energy efficiency of the HVAC system without comprising the natural air income. The system PFX Plate and Frame Heat Exchanger by Armstrong is a good choice due to a reasonable price and short payback period (Armstrong). EPC1 EPC2 ECP3 ECP4
Jan 16.410 43.220 59.380 9882.000
Feb 9.680 25.010 30.090 7081.000
Mar 3.180 9.940 21.190 4851.000
Apr 5.480 7.350 14.860 3824.000
May 6.380 8.180 27.190 6413.000
Jun 11.380 11.110 82.620 8142.000
Jul 13.620 12.610 42.810 9385.000
Aug 14.460 13.200 44.780 9817.000
Sep 8.080 7.340 29.280 6001.000
Oct 1.810 6.440 17.360 3913.000
Nov 4.830 14.280 25.330 5931.000
Dec 11.270 30.040 29.860 10305.000
TOTAL 106.580 188.720 424.750 85545.000
TOTAL 0.933 0.803 0.772 0.714
Total/ref. 1.402 1.522 1.762 1.578
EPC 3 [424.75 kwh/m2/ yr] / [241 kwh/m2/ yr] = 1.76 ECP2
[188.72 kwh/m2/ yr] / [124 kwh/m2/ yr] = 1.52
[85545 g/m2/ yr] / [54211g/m2/ yr] = 1.58
From the result, the EPC2 reduces to 80.3%, which is still below the energy usage code. Although the EPC primary reduces 37.8%, it is still almost two times as energy star 75. In addition, the EP4, CO2 emission has reduced to 71.4% to the original condition, but it is still 1.58 time higher than the reference. In this session, without major renovation of HVAC system, it is quite difficult to make a huge improvement.
Energy Conservation Method II â€“ Architecture features The second portion of renovation starts from architecture feature, including air tightness, insulation, absorptivity, and emissivity level of roof, window and walls. Since major building assemblies were constructed 25 years ago, the U values of the components are quite high. As for the glazing part, the U value and SHCG is quite high. Also, the air leakage is a major issue. To renovate the building, I choose R-30 Fiberglass, 2x8, R-15 XPS roof assembly with bright white finish from APOC/Gardner-Gibson Inc., type APOC 256 X, which has a 0.04 absorption coefficient and 0.85 of emissivity. For the wall I choose R-15 XPS, with red bricks as exterior finish to maintain the appearance of the building. Since the building has a huge portion of glazing on the facades, it is quite to reduce heat gain/loss to a similar size regular office building even with good glazing system I choose Aluminum frame w/o thermal break double pane low-E (E*=0.1) glass with Â˝" air space, which has a 0.29 U value and 0.31 SHGC. The airtightness of the building is not always the tighter the better. When the air tightness reach level 3 in the EPC tool, the energy consumption reach the minimum. It is because the leakage also helps natural air flow in the building, which could potentially lower heating or cooling demand.
EPC1 EPC2 ECP3 ECP4
Jan 4.500 18.050 35.750 8254.000
Feb 2.420 11.620 26.200 5961.000
Mar 1.120 7.050 22.920 4032.000
Apr 2.300 7.730 26.240 5751.000
May 5.570 11.350 38.510 8442.000
Jun 7.850 13.090 44.420 9738.000
Jul 8.410 13.170 46.570 10195.000
Aug 9.160 14.150 31.840 6979.000
Sep 6.000 11.360 38.560 8454.000
Oct 1.850 7.480 23.100 4632.000
Nov 0.800 6.910 21.410 4727.000
EPC 3 [393.98 kwh/m2/ yr] / [241 kwh/m2/ yr] = 1.59 ECP2
[134.48 kwh/m2/ yr] / [124 kwh/m2/ yr] = 1.1
[83634 g/m2/ yr] / [54211g/m2/ yr] = 1.54
Dec 2.540 12.520 28.460 6469.000
TOTAL 52.520 134.480 383.980 83634.000
TOTAL 0.460 0.572 0.697 0.698
Total/ref. 0.691 1.085 1.593 1.543
As it is shown, the EPC 1 only takes up about 20% of EPC primary and 40% of EPC 2. The renovation of thermal need of building has lighter impact on the whole energy conservation methods. With second phase of energy conversation renovation, the EPC 1 reduces to 46% to the original data. A well-insulated building results to reduction of energy usage for cooling and cooling which helps to reduce EPC 2to 1.1 and below the energy code. However, this choice is not much better compared to ECM I in terms of reduction of CO2 emission, which is still 1.54 time higher than the reference.
Energy Conservation Method III â€“ Building operation features The building operation and management could determine the level of building energy consumption. The most important changes in this phase is to improve the Building energy management systems to level 4, detecting faults of building and technical systems and providing support to the diagnosis of these faults, Reporting information regarding energy consumption, indoor conditions, and possibilities for improvement (prEN15232, 2006). In this way, the building system could avoid unnecessary waste in consuming systems. At the same time, with a more precise supervision, the thermal comfort level of the building could also potentially be improved. Also, the ROI period of BEMs is relatively short about 2 years (Bachman, 2012). Lighting control system also needs to be implemented since all the lights are turned on 24 hours every day even during weekends. When I visited the building during the weekends, the table lights are even on when nobody works in the offices. It wastes plenty of energy especially when the lighting is still Incandescent and fluorescent light bulbs.
EPC1 EPC2 ECP3 ECP4
Jan 18.500 27.000 41.560 10933.000
Feb 11.200 17.390 31.820 7421.000
Mar 3.720 7.930 19.060 4307.000
Apr 1.880 4.670 14.970 3296.000
May 5.680 6.690 22.720 4980.000
Jun 10.820 9.350 31.720 7812.000
Jul 13.150 10.570 35.860 7862.000
Aug 13.980 11.100 37.670 8258.000
Sep 6.040 6.770 23.990 5040.000
Oct 1.890 5.420 15.450 3434.000
Nov 5.700 10.600 22.360 5120.000
Dec 12.820 19.770 35.900 8397.000
TOTAL 105.380 137.260 333.080 76860.000
TOTAL 0.922 0.584 0.605 0.641
Total/ref. 1.387 1.107 1.382 1.418
EPC 3 [333.08 kwh/m2/ yr] / [241 kwh/m2/ yr] = 1.38 ECP2
[137.26 kwh/m2/ yr] / [124 kwh/m2/ yr] = 1.1
[76860 g/m2/ yr] / [54211g/m2/ yr] = 1.41
As the BEM system modification being applied simply, the effect is basically the same as renovating the building envelope. The smart use of the building system is really making difference in the energy consumption of the building. A well designed and well-constructed building could perform terribly if it is not appropriately used. Here, the CO2 emission has reduced to 64.1% of the original condition, but still higher than the reference by 1.4 times more.
Energy Conservation Combination To reach the goal of reaching Energy star Target Finder 75, we could combine all the potential ECM mentioned above together. EPC1 EPC2 ECP3 ECP4
Jan 6.580 10.280 19.610 4549.000
Feb 4.000 7.180 15.090 3460.000
Mar 0.830 3.940 11.810 2614.000
Apr 0.710 3.300 11.190 2453.000
May 3.440 4.330 14.690 3220.000
Jun 5.650 4.970 16.880 3700.000
EPC 3 [180.53 kwh/m2/ yr] / [241 kwh/m2/ yr] = 0.75 ECP2
[64.7 kwh/m2/ yr] / [124 kwh/m2/ yr] = 0.52
[40215 g/m2/ yr] / [54211g/m2/ yr] = 0.74
With all those technology combines together, the primary Energy usage finally drops to 180.53 kwh/m2/ yr, which basically reach Energy star target finder of 75. To achieve this level, the primary energy consumption reduces to 57.5% of the original data. The EPC reaches 0.52. The EPC reaches 0.52. The CO2 also drops below 1, and reduced to 47% of the original condition.
Jul 6.310 5.280 17.920 3928.000
Aug 6.870 5.480 18.590 4075.000
Sep 3.850 4.370 14.830 3252.000
Oct 0.490 3.390 11.360 2494.000
Nov 1.290 4.400 12.070 2693.000
Dec 4.280 7.780 16.490 3777.000
TOTAL 44.300 64.700 180.530 40215.000
TOTAL 0.416 0.343 0.425 0.470
Total/ref. 0.583 0.522 0.749 0.742
EPC Primamry monthly energy usage
70.000 60.000 50.000 40.000 30.000 20.000 10.000 0.000
Combined ECM 10
Cost analysis EPC Delivered monthly energy usage
The cost of retrofit is the most important decision making factor. If the payback goes beyond 10 years, it is quite difficult to persuade clients to accept the plans. However, if the retrofitting couldn’t reach a certain level, the energy saving effect will be limited. It is important to reach a balance between energy saving and cost of retrofitting. After all, to most people the significance of saving energy is to save consumption of pursing energy in a long term. Specifically, the part of energy consumption is the EPC 2, delivered energy, which is the part clients are paying for.
ECM 1 retroﬁt
60.000 50.000 40.000 30.000 20.000 10.000 0.000
If all the ECMs combined together, we could get the result of the delivered energy dropping from 234.91 kwh/m2/ yr to 64.7 kwh/m2/ yr, which give annual energy conservation of 170.21 kwh/m2/ yr, 170.21 kwh/m2/ yr x 3957 m2 = 673521 kwh / yr Tracking back to EPC, the energy consumption ratio of electricity to natural gas is about 63.13% to 36.87%. With the price of electricity in Atlanta of $0.15/kwh (Statistics, 2015) and $1.28/therm for natural gas based on the pre-pay plan (Commission, 2015), we save $67553 annually in energy consumption. 673521 * 63.13% * 0.15 = $63779 673521 * 36.87% * 0.0341 * 1.28 = $10838 $673521 + $10838 = $74617/year The list of retrofitting items and its resource is listed as below,
Name of Item
Heat recovery system
LED bulbs ( (Homedepot), 9W)
Wall (NERL) R-15 XPS,
Roof (NERL) R-30 Fiberglass, 2x8, R-15 XPS Windows (NERL)ow-E (E*=0.1) glass with Â˝" air space, which has a 0.29 U value and 0.31 SHGC Labor (buildingsguide) BEM system (Kamm, 2007) Total
If all three ECMs are combines together, we could get an initial investment of $541,943. If the annual interest rates in the next 10 years remains 5%. The undiscounted payback period is 6.42 years, and the discounted payback period is 7.46years.
338160 (average $80/m2) 3957
$2,500,000 $2,000,000 $1,500,000 $1,000,000 $500,000 $0
1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303132333435
($500,000) Discounted Payback
If the ECM breaks down to individual method, the payback period could be analyzed in detailed. For ECM1, MEP features, The annual consumption, (234.91 - 188.72) * 3957 = 182378 kwh The energy cost saved, 182378 * 63.13% * 0.15 + 182378 * 36.87% * 0.0341 * 1.28 = 20205 Name of Item
Heat recovery system
LED bulbs ( (Homedepot), 9W)
The ECM 1 could be paid back within a year; if it is only simply get light bulbs changed and added a heat recovery system. But it is important to remember this method didnâ€™t significantly reduce energy consumption as other tow methods.
$800,000 Discounted Payback
$600,000 $500,000 $400,000 $300,000 $200,000 $100,000 $0
1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303132333435
For ECM2, Architecture features, The annual consumption, (234.91 - 134.48) * 3957 = 397402 kwh The energy cost saved, 397402 * 63.13% * 0.15 + 397402 * 36.87% * 0.0341 * 1.28 = 44027
Name of Item
Wall (NERL) R-15 XPS, Roof (NERL) R-30 Fiberglass, 2x8, R-15 XPS Windows (NERL)ow-E (E*=0.1) glass with Â˝" air space, which has a 0.29 U value and 0.31 SHGC Labor (buildingsguide) Total
1153 m2 2354m2 719.2 m2
23.7 35.5 41.9
27312.3 83585.3 30180.5
338160 (average $80/m2) 479157
In this case, it 14.52 years to get it payback with a interested rate of 5% or 10.52 years without interest rates. It is not quite financial appeal to many of the clients. Also, it didnâ€™t count the design and other administration expense. However, this method is regarded as a deep retrofit, which is more fundamentally solve the thermal comfort issues in the building with consuming less energy. With less heat gain/ loss, the HVAC systemâ€™s burden is not as heavy, which could also potentially reduce the IAQ concerns.
$1,200,000 Discounted Payback
$800,000 $600,000 $400,000 $200,000 $0 ($200,000)
1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303132333435
For ECM3, BEM system features, The annual consumption, (234.91 - 137.26) * 3957 = 386401 kwh The energy cost saved, 386401* 63.13% * 0.15 + 386401 * 36.87% * 0.0341 * 1.28 = 42809 Name of Item
BEM system (Kamm, 2007) Total
The BEM system as it was stated, get payback within 2 years. At the same time, it save a large amount of energy.
Unit price 13.45m2 53221.6
$1,200,000 $1,000,000 $800,000 $600,000 $400,000 $200,000 $0 ($200,000)
1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303132333435
Amount Energy Saved annually 673521 kwh
ECM1 MEP features ECM2 Architecture features ECM3BEM system feature
<1 10.52 1.24
<1 14.52 1.26
182378 kwh 397402 kwh 386401 kwh
Based on difference financial budget, we could choose different method. Sometimes, deep retrofit like renovating the exterior envelop could really improve the building performance significantly if payback is less an issue.
Design Optimization In the current design, the building has generic windows that don’t provide enough shading in South side and partially on west side. Also, users don’t have enough control to the daylight level. As a result, users usually shut down the blinds all day or forced to bear with glare without sufficient consciousness or knowledge in lighting control. Another issue in the building is the daylighting of central area. Currently, the middle area has more than 50% of office which has no access to natural light at all. A DIVA model is operated to quantifying the day lighting. As the diagrams shows that central area has less than 50 lux throughout the whole year. In order to solve these problems, the new façade design has series smaller windows with size of 600mm x 900mm derived from the location of original windows. Each of the window is split into 6-12 modules to gain the flexibility of user control. This method could allow the natural light coming into space from different height and invite the light to further inner space. at the same time, it could help the 1st floor user to protect their privacy as well as invite the natural light in from higher windows. In general, the total glazing area doesn’t change except the extra openings on the roof area to invite natural light to central area. For each new window, the shading is composed with 4 pieces as movable elements. It could be fully closed and block 100% or open piece based on the internal lighting need. The transparent join are hidden behind each solid triangular shading device, so when those shading pieces open up, they could be connected by expanded transparent joints panels to gain the stability. The skylight light has same concept in design except for the size scaled up to 1.2m x 1.8 m, which is constrained by the located of the interior wall. The design modelling is accomplished by the grasshopper in Rhino.
February 21 st
April 21 st
July 21 st
Noverber 21 st
0.6m x 0.9m
1.2m x 1.8m
February 21 st
July 21 st
April 21 st
Noverber 21 st
With the design optimization, the lighting level of central space on second floor has been greatly improved as showing below. Also, due to better natural lighting condition, the lighting operation time get reduced from 1 to 0.65 during week day work hour, and shading reduction factor gets lower especially on south and west faรงade. I n this situation, the shading reduction factor are the average data for a year since the user could have more control to the shading, As it shows in the original simulation, the EPC 3 is 551 kwh/m2/yr when SRF are changed monthly, and the EPC 3 is 544 kwh/m2/yr when the SRF is average for whole year. As it shows the difference is only 1.3%. As it proves, the EPC data calculated with yearly average SRF is feasible. From the diagram, we could tell the EPC primary has lower from 544 kwh/m2/yr to 506 kwh/m2/yr by redesign the facade and roof. The diagram below shows that the cooling need and heating need get smaller with better lighting. 22.00 heating need original
heating need design opt.
cooling need design opt.
cooling need original
Tech-opt optimization In EPC, there are plenty of energy conservation methods with different level of optimization in adjusting energy consumption of buildings. Tech-opt provides us a platform to figure out the best combination of different method to reach least energy consumption under certain constrains such like present value or the effeteness of different level of technologies. As it is addressed before, the Smithgall student service building need to reach the following energy consumption standard. As the payback and present values tightly related to EPC 2 delivered energy, the final goal set in Tech-opt is to reach Energy Star 90, EPC 2 of 69.4 kwh/m2/yr. EPC 1
Energy Star 50
124 - 1
241 - 1
Energy Star 75
91.8 - 0.74
178.3 - 0.74
Energy Star 90
69.4 - 0.56
132.6 - 0.55
Energy Star 95
57 - 0.46
110.9 - 0.46
The optimization eventually will be evaluated by the financial rule. In this case, the setting is to get payed backed by 20 years. Based on the following calculation, Premium cost of mix of technologies = sum of cost of each applied technologies – total saved Total saved = A * [(1+i)n - 1] / i * (1+i)n A = annual saved = E (delivered baseline) – E (delivered optimized) •
E (delivered baseline) is the delivered energy when all the technology are in baseline, which is 127.3 kwh/m2/yr in this case.
i = inflation rate (Statistics, U.S. Bureau of Labor Statistics, 2015) •
The average in the past 10 years in US is around 2%. In this calculation, it is accounted as 3%
n = payback year = 20 • Per request, it is set as 20 years When premium cost is smaller than 0, the optimization gets payed back. To shorten the payback period while reaching the level of Energy Star, this case doesn’t plan to generate excessive energy by PV to sell back to the grid.
1. Lighting daylighting factor Daylighting sensor in this case is applied as optimization options. This sensor could avoid the unnecessary lighting when daylight in sufficient.
A 1 - Baseline (NULL)
A 2 - Partial sensor A 3 - Fully autom. sensor
2. Lighting occupancy factor The occupancy sensor could avoid the unnecessary lighting when no users occupy the space.
B 1 - Baseline (NULL)
B 2 - Partial sensor
B 3 - Fully autom. sensor
3. Lighting constant illumination control factor The dimmer could firstly control the light density controlled by users to improve the comfort level, especially the full lighting intensity usually causes glare.
C 1 - Baseline (NULL) C 2 - Partial dimmer C 3 - Fully autom. Dimmer
COST 0 2100 4200
amount 0 140 140
unit price N/A 14.97 56.98
4. HVAC The optimization uses Heat pump instead of chiller and boiler to improve the COP. Based on the size of the building, it needs seven 5 ton pumps to provide sufficient heating and cooling.
D 1 - Baseline HVAC D 2 - HVAC variation 2 D 3 - HVAC variation 3 D 4 - HVAC variation 4
COST 0 $ 14,400.00 $ 31,559.40 $ 80,494.56
amount N/A 12 12 12
unit price N/A 1200 2629.95 6707.88
5. Heat recovery type It could be used to maximize un-used heat with relative cheap equipment.
COST No heat recovery 0 Heat exchange plates or pipes (0.65) 1400 Two-elements-system (0.6) 1800 Loading cold with air-conditioning (0.4) 3100 Heat-pipes (0.6) 2200 Slowly rotating or intermittent heat exchangers 3460(0.7)
amount N/A 1 1 1 1 1
unit price N/A 1400 1800 3100 2200 3460
Exhaust air recirculation percentage
No exhaust air recirculation Exhaust air recirculation 20% Exhaust air recirculation 40% Exhaust air recirculation 60%
COST 0 11475.3 22950.6 34425.9
amount 0 3957 3957 3957
unit price 0 2.9 5.8 8.7
10. Solar Collector Surface Area This is the major method of getting hot water. It doesnâ€™t require much since the DHW is only needed in the bathrooms.
7. Building air leakage level It could be achieved by sealing the windows and wall, roof joints. Also, by replacing windows and walls, it could be imporved.
2 D0 Baseline Air Tightness D1 Air Tightness Improvement 1 D1 Air Tightness Improvement 2 D1 Air Tightness Improvement 3
COST 0 5104 1.4 5935 1.2 13256 0.6
unit price 0 /m2 1.29 /m2 envelope 1.50/m2 3.34 /m2 area
unit price N/A
9. Type of BEM system installed Class C means the installation of thermostat. Class B means higher level control.
1: Class D 2: Class C 3: Class B
amount N/A 2 piece 3 piece 4 piece
unit price N/A
11. Appliance In this office building, the major appliance include 120 computer, 10 printers, 5 refrigerators, 5 microwaves, 5 coffeemakers and 5 TV , also some plug load.
8. DHW Generation System This is the backup system for DHW supply.
COST 0 20000 30000 40000
Minimum Solar Col. area Maximum Solar Col. area Maximum Solar Col. area Maximum Solar Col. area
COST 0 32000 227840
amount N/A 160 160
unit price N/A 199 1424
Energy-Star Baseline Energy-Star Top 10% Energy-Star Top 5%
COST 10 0 6.3 103287 4.4 156997
unit price N/A
See sheet 2 in detail
12. Lighting Lighting has three options; include pure CFL, mix of CFL and LED, pure LED light. The light optimizations are not expensive and also have a significant effect in improve energy performance.
100% CFL (10 w) LED and CFL combo (8w) LED (4w)
COST 0 4500 9565
amount N/A MIX 319
unit price N/A MIX 29.98
13. Roof The roof component has a higher price since it require higher R-value. Also, the paint on the outer layers are very importnat to avoid the solare heat gain.
Roof Baseline 1 (0.24 - 0.7 - 0.6 ) Roof Improvement 2 (0.18 - 0.6- 0.6 ) Roof Improvement 3 (0.12- 0.5 -0.7 )
COST 0 173425 243904
amount 2234 2234 2234
unit price 0 77.629812 109.17816
14. Opaque Similar to roof, but R-value doesnâ€™t need to be as high. The cost is the highest since the amount is high. As the exterior material has been determined, the Absorption and Emissivity are fixed number regardless of the layers of the walls.
Wall Baseline 1 Wall Improvement 2 Wall Improvement 3
COST 0 242857 265004
amount 3387 3387 3387
15. Window Windows are key components in optimization because the solar gain in summer is really high. A low E coating that lower the SHGC could be significant to reduce solar gain. Usually the price of windows is quite higher. It may not be the best solution to choose best quality if the payback is required.
unit price 0 71.702687 78.241512
Window Baseline 1 (2.5-0.7-0.5) Window Improvement 2 (2.84 - 0.6 - 0.16) Window Improvement 3 (1.65 -0.5-0.26) Window Improvement 4 (1.53-0.4-0.18)
COST 0 75121 177072 244643
amount N/A 98 231 319.15
unit price N/A 766.54082 766.54545 766.54551
16. Specific fan power (new technology) This is part of the HAVC system. The fan power, a low cost portion, could influence the EPC
X1 X2 X3
COST 0 2160 4560
amount 12 12 12
unit price 0 180 380
Start with the test of reaching Energy star 90, the solver gives us following combination. Under this situation, the EPC 2 reaches 69.4 kwh/m2/yr, and could get a payback of $ 38,445 by the end of 20 years. As it shows, the three most expensive optimization options are the PV panels, Appliance and Windows. From the result, it clears shows that with PV panels generating partial of the energy usage, even the HVAC system doesnâ€™t have a quite high efficiency, the building could really easy reach Energy Star 90.
inventory of Energy Star 90
Lighting daylighting factor
Lighting occupancy factor
Lighting constant illumination control factor
HVAC variation 1
Heat recovery type
No heat recovery
Exhaust air recirculation percentage
No exhaust air recirculation
Building air leakage level
Air Tightness Improvement
DHW Generation System
Type of BEM system installed
PV module Surface Area (m2)
204 m2 1 m2 per piece
Solar Collector Surface Area (m2)
3 solar water colletor
Energy-Star Top 10%
LED and CFL combo
Roof Baseline 1
U = 0.24 Absor. = 0.7 Emiss. =0.6
Wall Baseline 1
U = 0.42 Absor. = 0.42 Emiss. =0.92
Window Improvement 2
U = 2.84 Emiss. =0.6 SHGC = 0.16
Speciﬁec fan power(new tech)
1.5 [W/(l/s)] Total
2095.8 H-COP = 2.05; C-COP = 2.88;
0.0 0 0.0
1.2 m3/h per ﬂoor area at Q4Pa
To maximize the financial benefit by 20 years, the new objective function is set to minimize the NPV which the enrgy consumption is still lower than 69.4 kwh/m2/yr. It could get benefits of $256,6762 by the year 20 with an inflation rate of 3%. The delivered energy is even reduced to 5.06 kwh/m2/yr. However, the initial cost rises to $512,676.5. It might be difficult to persuade owner to invest this amount initial cost. Also, this solution applied PV panels all over the roof surface (the space for skylight doesn’t is not taken for PV panels here),
but it uses the most basic wall, roof and windows, the most energy consuming option in appliance and lighting (full CFL), and without illuminance and daylight sensor. Although it didn’t consume grid energy, the options are not quite environmentally friendly, nor the Life cycle impact.
inventory of max payabck
category Lighting daylighting factor Lighting occupancy factor Lighting constant illumination control factor HVAC (COPs) Heat recovery type Exhaust air recirculation percentage Building air leakage level DHW Generation System Type of BEM system installed PV module Surface Area (m2) Solar Collector Surface Area (m2) Appliance (W/m2) Lighting (W/m2) Roof1 Opaque1 Window1 Speciﬁc fan power(new tech)
speciﬁc items A 1 - Baseline (NULL) B 3 - Fully autom. sensor A 1 - Baseline (NULL) D 3 - HVAC variation 3 Heat exchange plates or pipes No exhaust air recirculation D1 Air Tightness Improvement 2 Electric (0.75) 2: Class C PV area 3 solar water colletor Energy-Star Baseline 100% CFL Roof Baseline 1 Wall Baseline 1 Window Baseline 1 X3
H-COP = 3.31; C-COP = 3.75; 0.65 1.2 thermastat 1200 m2 1 m2 per piece 160 gallons/collector 11 w/m2 CFL 10 w/m2 U = 0.24 Absor. = 0.7 Emiss. =0.6 U = 0.42 Absor. = 0.42 Emiss. =0.92 U = 2.5 Emiss. =0.7 SHGC = 0.5 1 [W/(l/s)] Total
cost 0 7929.6 0 32411.4 1400 0 5935.5 0 32000 399200 30000 0 0 0 0 0 3800 512676.5
When PV panels become an option of the optimization, it seems easy to reach a high score in Energy Star. However, there are several potential problems that need some extra consideration. Firstly, the energy consumption is not the only rule of thumb in choosing certain technologies. For example, the traditional CFL is cheap, but when consuming the energy, the CO2 emission and excessive heat could be a serious problem. When improving roof, wall, and windows, the well-insulated components not only conserve energy but also improve the indoor thermal comfort and create a more steady condition. The manufacture of PV panels consumes plenty of energy and uses several of hazardous ingredients. Currently, the PV panels are still under initial steps, and when aging of PV is becoming a problem, the recycle, reuse and after-use life need to be considered as soon as possible. To utilize the energy collected by PV panels, it could either stored in battery on site, or input to grid system when generating excessive amount and use from grid in other time. The battery takes up a large volume and cost a huge amount of money initially. If sending it back to the grid, the fluctuation of energy inputting/outputting to the grid would be challenge the tolerance and stability of the grid. The solar heat collector is the major resource of the hot water, and it could provide 480 gallons (1840 L) of hot water to the building every day, which is sufficient to all users. Also, the electric DHW generator is installed as a backup system in case of excessive water usage or weather is too cloudy. To optimize the wall and roof are fairly expensive with a relatively subtle effect in saving energy. To analyze the different between two options, the energy consumption are split as the usage and self-generation. From the 3 chart we could tell that the, from energy star 90 to max payback, the delivered energy usage between these two are not much different. During summer/cooling season, the energy consumed by the max payback is even more than energy star 90 option. To make the max payback choice so energy efficient, the onsite generation makes a huge difference, which is about 6 time higher than the energy star 90. It comes to a discussion that if users should use as much energy as they can if the energy could be generated by renewable resources. If the appliance, lighting and building construction quality couldnâ€™t get improved, the process of using energy will still generate tremendously large amount of heat and cause severe heat island effect and eventually get into a unhealthy environmental-energy cycle. As the manufacturing process of PV panels become more mature, the efficiency rate of collecting solar energy is significantly improved. As a conclusion, the Energy star 90 result is the better choice in terms of initial cost and environmental impact even if it has less pay back.
Delivered Energy Usage
energy star 90
Total Delievered Energy
energy star 90
CO2 energy star 90
CO2 max payback
energy star 90
1.00 (1.00) 0
PV Energy Generation
Conclusion Based on the analysis, it states that by retrofitting portion of MEP, Architecture and BEM system, it is feasible to reach energy start target finder 75 by spending $479,075 at first step. Also, the NPV calculation shows that the payback period is 8.63 years without considering the price of labor and potential fluctuation of energy price. Also, as the architectural assembly gains the age, the insulation level will decrease, and the airtightness will be less effective, which need more sophisticated analysis later. Based on the current userâ€™s pattern, it seems that most users donâ€™t have sufficient sensitivity in terms of energy usage. An education outreach program could be arranged to raise people attention in using manually controlled lighting feature and other appliance. Other option is to implement it by improving the BEM system and building automation system.
In architecture renovation part, it could be much more efficient if it could integrate new design as part of deep retrofitting process, such as adding shading devices without compromising the appearance of the building. At the same time, by cooperating with BEM system, the natural ventilation could be embodied based on the temperature, humidity pattern of Atlanta. It needs proper design for natural ventilation feature, such as size of the fenestration and orientation. To allow natural ventilation, it is necessary to remove obstruction for the air flow the airtightness is not the tighter the better, when Building air leakage level reduce to 1-2, the energy consumption actually rises. During most of natural ventilation available seasons, the air leakage could implement the ventilation in a subtle way. Some Passive strategies may be integrated such as installing PV panels and solar thermal water heater. The HVAC system is usually quite expensive and requires a long payback period. It could be beneficial if the building performance could reply less on the HVAC system and create a naturally comfortable indoor environment. As the advance mechanical system get developed in the past 30 years, modern architecture theory leans more toward an irrational aesthetical perspective and the energy consumption was gradually ignored. As Le Corbusier said, â€œWindows are for the visual connection between indoor and outdoor space not for ventilation. That work can be handled by engineers and HVAC systemâ€?. It also was fully expressed in most of his projects, which causes a significantly influence to modern architecture design. To reach a balance of simply reducing energy consumption and pursuing purely aesthetic aspects is going to be a key topic in current architecture field. The design estimation further proved the effectiveness of the energy consumption consideration in design phase. Furthermore, it also proves that the comfort level can also be guaranteed as we try to reduce energy usage in design. In this case, to maximize the effectiveness of natural light helps to achieved the energy conservation as well as the aesthetic appearance of the bundling. In decision making of optimization should not be made by evaluating single parameters. To reach the targeted goal, the best combination is not necessarily the combination of all best options, especially when the payback comes into consideration. However, the first of everything is to set an appropriate target before searching for the specific strategies. As it mentioned, the pollution control should be considered from energy generation and energy usage. The generation could be managed by the resource of energy, which could be solved or alleviated by the on-site energy generation by PV panels. On the other hand, the problem caused by energy usage such as heat island effect need to be controlled from appliance and other types of energy usage.
Works Cited 1. Armstrong. (n.d.). Heating and Cooling. Retrieved 11 7, 2015, from http://armstrongfluidtechnology.com/en/products-and-services/heating-and-cooling 2. Bachman, K. (2012, 7 24). Controls, sensors use in building energy management systems forecast to grow. Retrieved 11 10, 2015, from Sustainable Manufacturer Network: http://sustainablemfr.com/energy-efficiency/controls-sensors-use-building-energy-management-systems-forecast-grow 3. Commission, G. P. (2015, 11). Georgia gas market's price chart. Retrieved 11 10, 2015, from http://www.psc.state.ga.us/GasMarketerPricesheets/201301_prepay.pdf 4. DOE. (n.d.). Building energy data book, chapter 3, commercial sector. In DOE, Building energy data book, chapter 3, commercial sector. 5. Energy Star. (n.d.). Energy Star Portfolio Manager. Retrieved 11 7, 2015, from Energy Star Portfolio Manager: https://portfoliomanager.energystar.gov/pm/targetFinder?execution=e3s1 6. Grondzik, W. T. (2010). Mechanical and Electrical Equipment for Buildings. New Jersey : John Wiley & Sons. 7. Homedepot. (n.d.). Dimmable LED Light Bulb. Retrieved 11 10, 2015, from http://www.homedepot.com/p/EcoSmart-60W-Equivalent-Soft-White-A19-Energy-Star-Dimmable-LED-Light-Bulb-4-Pack-A810SS-Q1D-01/206047134 8. Kamm, K. (2007, 4). Achieving Energy Savings with Building Automation Systems. Retrieved 11 10, 2015, from AutomatedBuildings.com: http://www.automatedbuildings.com/news/apr07/articles/esource/070322105430kamm.htm 9. Light comparion chart. (n.d.). Retrieved 11 7, 2015, from Comparison Chart, LED Lights vs. Incandescent Light Bulbs vs. CFLs: http://www.designrecycleinc.com/led%20comp%20chart.html 10. NERL. (n.d.). National Residential Efficiency Measures Database, v3.0.0. http://www.nrel.gov/ap/retrofits/index.cfm. 11. Passe, U. (2015). Designing Spaces for Natural Ventilation: An Architect's Guide. New York, NY: Routledge. 12. prEN15232. (2006). Energy performance of buildings â€” Impact of Building Automation Control. CEN/TC 247. 13. Statistics, U. B. (2015, 9). Average Energy Prices, Atlanta â€“ September 2015. Retrieved 11 10, 2015, from Southeast Information Office: http://www.bls.gov/regions/southeast/news-release/averageenergyprices_atlanta.htm 14. UCLA. (n.d.). Climate Consultant. Los Angeles, CA, USA.
Remote Desert Research Station
Author: Tianyu Feng
Abstract To utilize natural and renewable energy in modern architecture is becoming a dominant research direction. The remote desert research station Abstract (RDRS) is designed with a unique hypothesis of utilizing solar energy and rain water in Saguaro National Park, Tucson, Arizona, which is in an extremlydry and hot climate condition. As a summer studio project, the design had been finished within 7 weeks including a one-week field trip to Phoenix-Tucson area, Arizona. The main objective of this project is to design a pilot Remote Desert Research Station (RDRS) in the western portion of Saguaro National Park. A specific site wasn’t assigned, therefore, the project of the station would be considered to fit in a general condition in the park. The RDRS will be staffed by 6 University of Arizona students, faculty, and/or staff. Researchers will gather soil, water, and plant samples, tag and track wildlife, and record geographic information. The RDRS will serve as “home base” and staging point for extended field research excursions and will provide for temporary data and specimen storage. No main power or water will be transported to the site. which means the energy and water usage of RDRS should be self-sufficient with all required set of energy and water catchment systems. As it serves for university staffs, the RDRS will not be operated during the hot summer months of June to August. The RDRS must be designed to be secured from vandalism, animals and weather during this unoccupied period. The design will be approached from biomimicry as a design methodology. Through 3.6 billion years of evolutionary trial and error, nature has developed and perfected the design of a wide variety of systems, structures, processes and materials. The extreme climatic conditions of the desert represent clear design drivers and hold rich potential for formal, material, and strategic architectural response. The study of biological and built forms evolved in response to the desert climate will serve as the foundation of studio research.
Average Annual Temperature
The remote desert research station (RDRS) is located at a western part of Saguaro Nation Park, Tucson, AZ. The climate of Tucson, Arizona is extremely dry with dramatic daily temperature swings. During summer, the average temperature could reach up to 100 °F. During winter, the average temperature could drop to 40 °F. To achieve the passive energy standards, it needs to consider both heat gain/loss conditions in different seasons. The Average Annual Precipitation average annual participation in Saguaro National Park is 12.18” (30.25 cm), which needs to feed a huge water catchment area to collect enough water to meet the yearly needs. In addition, it is beneficial to preserve buildings and create possibility to cool down the building by creating humidity. In order to truly learn from native architecture and the habits of local living beings, we visited precedent examples during the field trip, including modern architecture, historic relics and natural parks. When we were at the Phoenix area, we visited the Burton Barr Library designed by Will Bruder and Arabian Library designed by Richärd+Bauer in Scottsdale. As the representative modern architecture in this area, both buildings are designed to respond the local climate. The central core surrounded by the non-accessible pond in Burton Barr Library(Image1 and 2) accelerates the air flow by utilizing solar chimney effect and cools down the building by increasing the humidity within it. The east and west sides of the building are covered with a double façade to reduce the heat gain from solar radiation. The double height top floor is designed to pull up hot air and speed up ventilation. A sky light provides enough natural light to readers during daytime hours. The Arabian Library is designed as a spiral shape from floor plan. It creates a shading effect by utilizing the building itself (Image 3). Also, low windows are mostly located on the south elevation to avoid excessive sun light. On the north elevation, large windows are designed to accept ample soft natural light. We also visited Pueblo Grande Ruins at Phoenix and Casa Grande Ruins near Tucson (Image 4). In ancient times, people constructed the adobe walls extremely thick, which is a good application of thermal mass from modern perspective. It could keep the room temperature consistent all year round. The sizes of windows is minimized (about 1’ x 1’/30cm x 30cm) to gain the least amount of heat while admitting an acceptable level of natural light. Within the ruins complex, the most important room is usually elevated to second floor and in the central area of the complex. It could prevent the room from being radiated by solar heat directly or absorb heat from ground. It could also avoid heat loss when outdoor temperature is low. In the Desert Botanical Garden, we figured most of the living beings could survive in the extreme climate by residing underground, covering with thick furs/skin or unique food habit. The most impressive animals is the desert tortoise. The shell protects the internal soft body. At the same time, the dome shape accelerates air flow inside of the shell and expels heat. During winter, the shell helps the body stay warm. From the trip, I figured out that there are numerous representative characteristics from precedent studies that could be applied toward my design. In passive energy architecture the most dominant strategies are to accelerate air flow, pull out hot air when the temperature is high, utilizing solar energy and introduce humidity.
Image 1. Burton Barr Library South West View
Image 2. Burton Barr Library Performance Diagram
Image 3. Arabian Library Interior, Viewing Out
Image 4. Pueblo Grande Ruins
Design development At the beginning of the design process, I started with a series of research of desert animal and vegetation as required with a biomimicry approach. The most impressive animal to me is the desert tortoise with its shell. As it is shown in the diagram 1, when air comes in the dome shell from a tiny entrance, the air flow will be sped up due the pressure difference. It brings heat away quickly. The ratio of the width of shell to the length of shell is around 1:5, which aligns with the best situation to accelerate the air flow. Finding inspiration in the shell, my initial proposal is to create a super structure shell with four different types of panels to cover it. They are a Photovoltaics (PV) panel, a solar heat collector, a translucent panel, and a high reflective panel (diagram 3). Considering the water collection, all the panels will create a seamless sloped surface to collect water in a large water tank. The roof are mostly tilted down toward the south side with a calculated slope to receive solar energy with PV panels and solar heat collectors. The PV panels absorb solar energy which is converted into electricity. The energy will provide basic lighting, radiant space heat in winter and power for lab equipment, such as refrigerator and small operation light. Solar heat collectors would directly heat up water to provide basic hot water usage. In order to prevent glare, the translucent panels are designed to filter intense natural light and create a comfortable luminance underneath of the shell. In the desert, people could easily get lost without an obvious way-guiding object. The highly reflective panels on the top of the shell reflect daylight and make the whole building shine in the desert. People could easily find their ways back as they follow the direction of shining landmark.
Diagram 1 Inspiration
The shell could be regarded as four sections, the tail section, west section, true south section and east section (diagram 2). Most PV panels and Solar Water Collector are located on true south section. Those panels could guarantee the primary energy generation. More PV panels and Solar Water Collectors will spread out on other sections in ideal weather conditions. The intention is to capture more energy when sunlight hits the shell from other directions, which could provide energy to be potential use for heat radiator during winter, operating any lab machines or any unexpected weather changes. The reduction of efficiency is smaller than 10%. The tail of the shell will extend to the ground on west side to avoid glare on the building during late afternoon. At the east side, the shell will shade part of the building due to the different needs for light intensity of the internal programs. Judging from North- South section, the shell extends out from the roof edge more than Â˝ of the building width on the south side to provide shading for the south elevation. All of the panels are almost equally spread out on the entire shell, which will avoid over-concentrated light. Aesthetically, the pattern creates a sense of flow.
PV Panels Solar Water Heater Transparent Panel
High SRI Material
High SRI Panels Way finding tool
Solar Water Heater Solar to Hot water
Diagram 2 Panel arrangement
PV Panels Solar to Electricity Diagram 3 Four types of panels
The design of the enclosed building underneath of the shell starts from orientation. As the diagram 4 shows, the dominant wind direction is southeast and northwest. In order to create good ventilation, the main walls of the building are perpendicular to wind direction to potentially receive maximum air flow. The building is two-story structure with a two-story tall central space. It is to pull up heated air from the lower level by utilizing volume and pressure difference. Each single space has windows on both south and north façades, which creates the possibilities of cross ventilation and natural light from different orientations. The size and shape of windows are designed according to orientation. The windows on south side are minimized and lower to the floor level. Only sunlight with a low angle could directly get into the room. The windows are larger on the east side since the morning light is not as strong. The north façade is designed with large windows, and it is also the main natural light resource. The solid wall is fairly thick and mainly made of concrete. It will provide sufficient thermal mass to keep the room temperature relatively consistent. The roof of the building follows the slope of the shell, and the central area is open with skylights. The arrangement of the program is determined due to natural climate conditions and the special needs of each program. As it shows in diagram 6, the living space is arranged at the center space of the first floor. The bedroom space has two alternative choices. The first space is on the east side of the first floor. The intention is to get plenty of morning solar radiation since the shell would only shade a small portion of the first floor. It wouldn’t create too much interruption since the whole building would only staff 6 people at most. During summer, people could also choose to move the bedroom space to the outdoor terrace on the west side of second floor since the west side would be completely covered by the shell. The terrace, with great view and convenient access creates an active social space for the staff at the same. Natural ventilation could create a comfortable outdoor environment even when the temperature is above 75 °F. The lab space is arranged on the east side of the second floor, and it is only half closed from the central core. The main natural light comes from clearstorys window on the north façade.
1. Face the wall to dominant wind direction 90d
3. Create skylight to light up space with reflected light of the shelter
Diagram 4 Wind rose
2. Create a core to ultilize stacke ventilation& solar chimney
4. Elevate North wall, Maximise sunlight
Diagram 5. Form development
Lab Bedroom Living Space
Winter Situation Diagram 6. Program design
Rendering 1 exterior viewing to west side of the building
Roof Plan Floor Plan --- 1’ = 1/32”
Solar Energy Usage The most significant factor influencing the installation of PV panel and solar water heater are angles and area. The latitude of Tucson, Arizona is 33º 26' N. According to the MEEB, the most efficient angle for PV panels is “latitude - 15°” when it faces true south. The most efficient angle for solar water collector should be the same. The panels in the calculations are the portion on the true south shell. It will guarantee the greatest energy and hot water generation. The PV panels sitting on other portions of the shell will work as supplement in case the staff needs to use heat radiator during winter, operating any lab machines or to accommodate any unexpected weather changes. The detailed calculation process is listed below. Part I: Calculation of Photovoltaics (PV) panels Step1. List of the regular daily energy usage (unit W hr/day) Living Space Microwave Refrigerator Coﬀee maker 2 central Lights Bedrooms 6 lights 1 central light Bathrooms 1 light Water pump
11w x 6 x 2hr = 132 W hr
Lab 6 computers 1 lab monitor 6 phone chargers 2 concentrated lights 2 sets of Basic lab equip. Specimen Storage refrigerator
22 x 4hr = 88 W hr
Assume a 10% changing range.
22x 4 = 88 W hr 750 x 4 = 5400 W hr
Total Energy Usage: 36,480 W hr x 110% = 40128 W hr/DAY
700W x 1hr = 700 W hr 540 W x 24hr = 12,960 W hr 800W x 1hr = 800 W hr 22W x2 x 4hr = 176 W hr
Step2. Calculate the angle Tucson Altitude is: 33º 26' N The best PV panel angel: 33-15= 18 º True South
40w x 6 x 4hr = 960 W hr 150W x 24hr = 3600 W hr 24 W x 1hr = 24 W hr 110w x 2 x 2hr = 440 W hr 80w x 2 x 4hr = 540 W hr 540W x 24hr = 12,960 W hr
Step3. Calculate the size of PV panels From the solar radiation chart on MEEB, we could get 1. January: 4.6 kWh/m2/day --- 0.62 kWh/ft2/day Temperature: 10.7°C Monthly Average Incident Solar Radiation: 470 wh/m2/day 2. April: 7.8 kWh/m2/day --- 0.87 kWh/ft2/day Temperature: 18.8°C Monthly Average Incident Solar Radiation: 680 wh/m2/day 3. August: 6.6 kWh/m2/day --- 0.74 kWh/ft2/day Temperature: 29.2°C Monthly Average Incident Solar Radiation: 540 wh/m2/day The three months listed above are the time period of the least, medium, and the most solar radiation. In order to make sure every single month receives enough solar energy, it is better to use the January data since it is the worst case scenario. All the data is based on the 10% efficiency of PV panels, which is the most common type. In order to collect enough rain water, the shell surface is quite large. Considering economic benefit, the highly efficient PV panels wouldn’t be the first choice. 40128 W hr/DAY / 470 wh/m2/ day = 85.4 m2 = 768.4 ft2 Part II. Calculation of Solar Water Collector The only water resource is rain water. The usage of water should be minimized. The portable water is not included since it is considered to be supplied from outside. Step1. List of the regular daily water usage (unit: gallon/day) 5-minute Shower (6 people once per day) 15 gallon x 6 = 90 gallon Others 30 gallon Total Water Usage: 120 gallon
Step2. Calculation the area of water collector According to the MEEB part II, the equation of calculating the amount of heat (Q) is Q (daily heat needed) = 8.33 x gallon per day x (Ts – Tg) Ts is the storage temperature --- 110 °F; Tg is the ground water temperature --- 60 °F Q (daily heat needed) = 8.33 x 120 x 50 = 49980 BTU System efficiency = 0.8 x collector efficiency Collector efficiency: 0.7(the common data) System efficiency = 0.8 x 0.7 = 0.56 Daily insolation = Clear day total x (Average day total / Clear day total) Clear day total: 2356; Average day total: 1874; Clear day total: 2390 Daily insolation = 2356 X (1874/2390) = 1847 BTU/ sq. ft. day Collector area = daily heat needed x percent solar desired / daily insolation x system efficiency Collector area = 49980 x 100% / (1847x 56%) = 48.32 ft2 Facade Sunlight Radiation Study(Vasari)
Water Usage The average annual precipitation is 12.18” (30.25 cm). The roof size should be large enough to collect enough rain water for regular daily usage and create enough shading area for outdoor activities. The roof sizing calculation is as follows. For the sake of ease of calculation, the rain collection portion is divided into 5 pieces (diagram 8 ). Area of roof (unit: ft2) 1 2 3
80 x 29 x ½ = 1160 ft 2 80 x 19 x ½ = 760 ft 2 54 x 39 x ½ = 1053 ft
4 23 x 54 x ½ = 621 ft 2 5 (69 + 43) x 45 x ½ = 2520 ft 2 Total area: 6114 ft
Diagram 8. Roof division
Besides the area of roof, the total daily water usage will also determine the size of water tank. There is plenty of space underneath of the tail of the shell. The clear height is less than 6 feet and wouldn’t be accessible by users. The tank is covered by the tail and half buried into the ground. In order to calculate the size of water tank, the significant factors are Catchment Yield, Usage, Net Water and Cumulative Capacity Adjusted for Actual Size. In most months, the usage of water is more than water catchment. The main water storage heavily relies on June to August and assume taht the water tank is 15,000 gallons. When people leave the station at May, the water remaining is 1677.4 gallon. If the precipitation reduction is less than 0.71” every year, the water storage wouldn’t be affected at all. When the water collection exceeds the volume of the tank, the extra water will be piped out through an overflow. Total water usage (unit: gallon) rea ion A
r co wate Rain Water Tank
5-minute Shower (6 people once per day) 1.6-gallon ﬂush toilet (10 time per day) Others Total Water Usage: 140 gallon
15 gallon x 6 = 90 gallon 1.6 gallon x 10 = 16 gallon 34 gallon
Diagram 9. Rain water collection system
Water tank calculation (unit: gallon) Month & Rainfall
Formula for the calculation 1. Catchment yield = Precipitation x roof area 2. Cumulative capacity adujusted for acutral size = CCAfAS (Former month) + Net water
July August September October November December January February March April May June
2.34" 2.24" 1.18" .86" .62" .97" .97" .96" .77" .36" .17" .21"
Catchment Yield Net Cumulative Cumulative Capacity Usage (gallon) Water Capacity Adjusted for Actual Size 8918.5 0 gal 8918.5 8918.5 8918.5 8537.4 0 gal 8537.4 17455.9 15000 17753.3 4497.4 4,200 gal 297.4 15000 3277.7 4,340 gal -922.3 16831.0 14077.7 1615.0 4,200 gal -2588 14243 11489.7 3697 4,340 gal -643 13600 10846.7 3697 4,340 gal -643 12957 10203.7 3658.9 4,060 gal -401.1 12555.9 9802.6 2934.7 4,340 gal -1405.3 11150.6 8397.3 1372.1 4,200 gal -2827.9 8322.7 5569.4 647.9 4,340 gal -3692.1 4630.6 1877.3 800.4 0 gal 800.1 5430.7 2677.4 3; 2677.6 gallon = 358 ft it give a 0.71â€? annual precipitation reduction.
Building material and assembly The choice of construction material and assembly method could be rather influential to indoor temperature. As it has been discussed before, the walls as valuable thermal mass could protect indoor space from excessive heat gain or loss. The air gap is assembled as a critical component to stop moisture exchange. The interior space is finished with gypsum wall. For the exterior finishing, the coarse concrete stucco is assembled to avoid sunlight reflection, which could avoid the temperature raise around the building. The windows are constructed with triple-panel glass. The two layers of air gaps are sufficient to block the heat transfer. This type of glass could refract sunlight three times, which could also reduce the intensity of the ultraviolet radiation. The roof is unusually thick, assembled with extra insulation to keep the room temperature stable. At the edges of the shell, the water gutter is embedded and flush with the surface of the shell for aesthetic reasons.
Close up period During June to August, the building would be vacant. In order to keep the vandalism, animals and sandstorms out, another layer of protection is required. For the sake of installation convenience, the cover would be made of 1/16â€? thick metal sheet. The metal sheet is soft as fabric and strong as regular metal. When people occupied in the building, the metal sheet could be rolled up and hidden under the shell. The metal covering is made of translucent modules and highly reflective modules, which could extend the pattern on the shell. When people leave the building, they could simply pull down the metal sheet and hook it on the deck. The metal sheet will follow the form of the shell and the building, which could seal the building completely. The buffer zone between outdoor and indoor space could avoid direct sunlight radiation indoor facilities and furniture.
Pull Down the Metal Sheet
Close Down Diagram 10 Metal sheet cover perferance
Rendering 2. Close up Period
Conclusion From ventilation, water usage, energy usage and materiality, the Remote Desert Research Station is a comprehensively considered project. As a project base in biomimicry, the RDRS has been inspired from desert tortoise. The RDRS has not only simulated the form and pattern of the tortoise but also learned from how the tortoiseâ€™s shell works. As a passive energy structure the RDRS has fully taken advantage of the shell and set up a complete system of solar energy and rain water collection within the special structure. It has greatly reduced the need for imported energy by fully utilizing any native and renewable resources, which is a practical precedent for future energy-efficient architecture. Rendering 3 Interior view to the central core
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