Energy Analysis using Home Energy Efficient Design (HEED) for New ...
Energy Analysis using Home Energy Efficient Design (HEED) for New Orleans Low-Cost Residential Housing California State Polytechnic University, Pomona Department of Architecture Arc 499 - Tools For Sustainability Juintow Lin Fall 2009 PROJECT TEAM Salma Abdelghani, Eric Carbonnier, Mike Yao INTRODUCTION The new competition will feature one national project site challenge that focuses on LEED for Homes, affordable housing, universal design and modularity. The competition will comprise two categories: students and young professionals. Two student and two young professional designs will be selected from the local competition finalists and will see their designs built in New Orleans. USGBC -Announcement COMPETITION OBJECTIVES The low-cost single family residential home is situated on a 32’ wide by 100’ long lot oriented north/south with the south side facing the street. The house is expected to be 800 square feet and capable of achieving LEED Platinum. Design solutions should consider various construction methodologies to attain a low-cost value. EXERCISE Project Teams are tasked with using Home Energy Efficient Design (HEED) to assist in the design process of the New Orleans Design Competition. HEED is an energy design tool that can evaluate and compare various building components and systems for analysis of sustainable principles. CONSTANT VALUES All schemes used the following values and criteria as constants throughout each exercise. Total square feet: 800 Number of occupants: 2 Comfort Zone 70°-75° Weather File: New Orleans-Lakefront AP, LA, USA, (TMY3) Utility Rates
ENVELOPE STUDY
Scheme Name Base Scheme E1 E2 E3 E4
EXTERIOR WALL SCHEMES Cooling Heating Description kBTU kBTU Wood or Vinyl Siding on 2x4 Wood Studs at 16", Plaster Board Interior 5,808 5,791 Wood or Vinyl Siding on 2x6 Wood Studs at 24", Plaster Board Interior 5,280 4,470 Stucco or Face Brick on 2x6 Wood Studs at 24", Plaster Board Interior 5,333 4,573 Stucco on 8" Hollow Concrete Block, +Insulation, 2x4 Stud Wall, Plaster Board 5,452 4,131 Stucco on 4-1/2" SIPS Panels (OSB, 3-5/8" + Polystyrene, OSB), Plaster Board 5,055 4,114
Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
9,750
-9%
-23%
-32%
9,906
-8%
-21%
-29%
9,583
-6%
-29%
-35%
9,169
-13%
-29%
-42%
11,599
Analysis: Based on the results, the Stucco on 4-1/2" SIPS Panels (OSB, 3-5/8" + Polystyrene, OSB), Plaster Board was the most efficient upgrade because it has a reduced energy load by 42%. We were able to determine that the Stucco or Face Brick on 2x6 Wood Studs at 24", Plaster Board Interior was not as successful in terms of energy efficiency.
FENESTRATION STUDY Scheme Name Base Scheme F1 F2 F3
Description
FENSTRATION SCHEMES Cooling Heating KBTU kBTU
Clear Double Pane, Low-E squared Clear Argon Filled Double Pane, Low-E squared/Without West Windows/Vertical Fins East Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas/Vertical Fins East and West Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas/ One Less North Window
Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
5,808
5,791
11,599
5,350
5,872
11,222
-8%
1%
-6%
5,496
5,347
10,843
-5%
-8%
-13%
5,309
5,236
10,545
-9%
-10%
-18%
FENESTRATION STUDY (continued) Base Case
F1 • West Windows Removed • Clear Argon Filled Double Pane, Low-E squared
F2 • Vertical Fins on East and West Elevations.
F3 • Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas • One Less North Window • Vertical Fins on East and West Elevations.
Analysis: There are typically three factors that are important when analyzing the fenestration techniques. The factors are: Solar heat gain coefficient (SHGC), t vis (transmittance), R-value. The three factors combined create a more efficient design. Based on a comparison amongst the three schemes for fenestration, we were able to determine that Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas/ One Less North Window performed efficiently because of a very high R-value in the manufacturer’s specifications. The website we visited was: www.efficientwindows.org and the product we specified was for the east and west fenestration. It had the lowest U-value (0.18) out of all their products available specifically for New Orleans. BUILDING GEOMETRY STUDY
Scheme Name Base Scheme BG1 BG2 BG3 BG4
Description Flr. to Flr. 9', Flr. To Clg. 8', Two Storey Flr. to Flr. 12', Flr. To Clg. 10' Flr. To Flr. 9', Flr. To Clg. 8', One Storey 4-Storey Option Extended Overhang all Around
Base Scheme
BG1
BUILDING GEOMETRY SCHEMES Cooling Heating kBTU kBTU Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
5,808 6,198
5,791 7,459
11,599 13,657
7%
29%
36%
5,460 6,411 5,682
5,357 6,737 5,696
10,817 13,148 11,378
-6% 10% -2%
-7% 16% -2%
-13% 27% -4%
BG2
BG3
BG4
Camelback House Floor – Floor 9’
Camelback House Floor – Floor 12’
Single Storey
3 Storey + Garage
16’ x 52’ Single Storey
Analysis: We looked at the different plan configurations that would work with an 800-square foot building. Our base case was a 2-story home. After a comparison of a single-story, two-story and threestory configuration, it was evident that the one-story house (Scheme 2) with a floor-to-floor height of 9-ft had the lowest reduction totals of heating and cooling loads. Miscellaneous and Behavioral
Base Case
Scheme 1
Base Case
Scheme 2
Scheme 3
Scheme 4
Scheme 4
Scheme Name Base Scheme M1 M2 M3 M4
Description Base Case with default settings Thermostat changes Ext. Light Slatted blinds, automated Energy Star Heating/ Energy Star Cooling Energy Star Heat/Cool, Air Retardant,vent.
MISCELLANEOUS SCHEMES Cooling Heating kBTU kBTU Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
5,809 5,809 5,231
5,791 5,763 5,754
11,600 11,572 10,985
0% -10%
0% -1%
0% -11%
5,490
5,019
10,509
-5%
-13%
-19%
5,341
4,916
10,257
-8%
-15%
-23%
Analysis: The data shown here represents different design decisions using thermostat changes, shadings/blinds/overhangs, HVAC improvements and ventilation. Each scheme analyzed one aspect and the conclusion here is that using energy-star heating and cooling systems, an air retarding house wrap and high natural ventilation (by opening windows as needed) proved to have a total reduction of 23% versus as compared to the base case.
EXTRA CREDIT EXTRA CREDIT SCHEME [HIGH PERFORMANCE] Scheme # Base Case 1
Scheme Name Base Scheme High Performance
Cooling kBTU
Heating kBTU
Total kBTU
5,808
5,791
11,599
2,705
1,395
4,100
CLG Reduction
-53%
HTG Reduction
-76%
Total Reduction
-129%
CO2 production LBS
$ Energy cost/Year
5,316
$222
4,081
$165
Electricity in the West South Central U.S. is primarily produced by coal resulting in must higher CO2 emissions compared to states with cleaner electrical production. New Orleans electrical consumption compared to California will result in higher CO2 emissions for the same expenditure. Alternative electrical production is highly recommended.
CO2/kWh Comparison Total CO2 Production California 686 Louisiana 2,993 Wyoming 4,934
Analysis: We customized a scheme that was able to derive a total energy cost per year of $165, versus the base case of $222/year. The design is a 3-story camel-back dwelling that is raised off the floor (unoccupied space; to serve as a garage). It is enclosed by break-away walls that would keep the structure intact in case of a natural disaster or flooding. No modifications were made to the base case design in terms of: level of insulation (current energy code), windows (cleardouble pane low e-squared windows), roofs (medium-colored shingles, naturally ventilated), overhangs fixed all year long. Here is a list of the modifications made using a combination of different design variables to achieve a high-performance option on annual energy load: • Addition of 4 skylights dispersed (fixed) • Walls were 6-inch SIP’s • Fan-ventilated attic • Concrete floors, tiled with an unheated garage carport open to exterior • Infiltration and weather stripping: House wraps and sealed ducts added to default standard construction • Ventilation: high-natural ventilation (up to 20 air changes per hour; no fans) • Heating: Best available furnace • Cooling: Best available air conditioner
CONCLUSION HEED is a useful sustainability tool that is helpful for obtaining instantaneous results and calculations. There are different options to consider and HEED is able to make strong comparisons between energy performances. As architecture students, it is important to run several tests to determine the best results for your clients and the environment. The accuracy within HEED allows for the users to input their own U-values (from manufacturers) to customize their needs. In most of our comparisons, the results did not show a high level of variation, yet it is still valuable to know how to save money by simple architectural decisions made to the final outcome. The resources we used to aid us in our design decisions came from the Szokolaytables and the Kleissner Caretaker energy analysis data.
ENVELOPE STUDY
Scheme Name Base Scheme E1 E2 E3 E4
EXTERIOR WALL SCHEMES Cooling Heating Description kBTU kBTU Wood or Vinyl Siding on 2x4 Wood Studs at 16", Plaster Board Interior 5,808 5,791 Wood or Vinyl Siding on 2x6 Wood Studs at 24", Plaster Board Interior 5,280 4,470 Stucco or Face Brick on 2x6 Wood Studs at 24", Plaster Board Interior 5,333 4,573 Stucco on 8" Hollow Concrete Block, +Insulation, 2x4 Stud Wall, Plaster Board 5,452 4,131 Stucco on 4-1/2" SIPS Panels (OSB, 3-5/8" + Polystyrene, OSB), Plaster Board 5,055 4,114
Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
9,750
-9%
-23%
-32%
9,906
-8%
-21%
-29%
9,583
-6%
-29%
-35%
9,169
-13%
-29%
-42%
11,599
Analysis: Based on the results, the Stucco on 4-1/2" SIPS Panels (OSB, 3-5/8" + Polystyrene, OSB), Plaster Board was the most efficient upgrade because it has a reduced energy load by 42%. We were able to determine that the Stucco or Face Brick on 2x6 Wood Studs at 24", Plaster Board Interior was not as successful in terms of energy efficiency.
FENESTRATION STUDY Scheme Name Base Scheme F1 F2 F3
Description
FENSTRATION SCHEMES Cooling Heating KBTU kBTU
Clear Double Pane, Low-E squared Clear Argon Filled Double Pane, Low-E squared/Without West Windows/Vertical Fins East Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas/Vertical Fins East and West Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas/ One Less North Window
Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
5,808
5,791
11,599
5,350
5,872
11,222
-8%
1%
-6%
5,496
5,347
10,843
-5%
-8%
-13%
5,309
5,236
10,545
-9%
-10%
-18%
FENESTRATION STUDY (continued) Base Case
F1 • West Windows Removed • Clear Argon Filled Double Pane, Low-E squared
F2 • Vertical Fins on East and West Elevations.
F3 • Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas • One Less North Window • Vertical Fins on East and West Elevations.
Analysis: There are typically three factors that are important when analyzing the fenestration techniques. The factors are: Solar heat gain coefficient (SHGC), t vis (transmittance), R-value. The three factors combined create a more efficient design. Based on a comparison amongst the three schemes for fenestration, we were able to determine that Triple-Glazed with Low Solar Gain, Low-E Argon/Krypton Gas/ One Less North Window performed efficiently because of a very high R-value in the manufacturer’s specifications. The website we visited was: www.efficientwindows.org and the product we specified was for the east and west fenestration. It had the lowest U-value (0.18) out of all their products available specifically for New Orleans. BUILDING GEOMETRY STUDY
Scheme Name Base Scheme BG1 BG2 BG3 BG4
Description Flr. to Flr. 9', Flr. To Clg. 8', Two Storey Flr. to Flr. 12', Flr. To Clg. 10' Flr. To Flr. 9', Flr. To Clg. 8', One Storey 4-Storey Option Extended Overhang all Around
Base Scheme
BG1
BUILDING GEOMETRY SCHEMES Cooling Heating kBTU kBTU Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
5,808 6,198
5,791 7,459
11,599 13,657
7%
29%
36%
5,460 6,411 5,682
5,357 6,737 5,696
10,817 13,148 11,378
-6% 10% -2%
-7% 16% -2%
-13% 27% -4%
BG2
BG3
BG4
Camelback House Floor – Floor 9’
Camelback House Floor – Floor 12’
Single Storey
3 Storey + Garage
16’ x 52’ Single Storey
Analysis: We looked at the different plan configurations that would work with an 800-square foot building. Our base case was a 2-story home. After a comparison of a single-story, two-story and threestory configuration, it was evident that the one-story house (Scheme 2) with a floor-to-floor height of 9-ft had the lowest reduction totals of heating and cooling loads. Miscellaneous and Behavioral
Base Case
Scheme 1
Base Case
Scheme 2
Scheme 3
Scheme 4
Scheme 4
Scheme Name Base Scheme M1 M2 M3 M4
Description Base Case with default settings Thermostat changes Ext. Light Slatted blinds, automated Energy Star Heating/ Energy Star Cooling Energy Star Heat/Cool, Air Retardant,vent.
MISCELLANEOUS SCHEMES Cooling Heating kBTU kBTU Total kBTU
CLG Reduction
HTG Reduction
Total Reduction
5,809 5,809 5,231
5,791 5,763 5,754
11,600 11,572 10,985
0% -10%
0% -1%
0% -11%
5,490
5,019
10,509
-5%
-13%
-19%
5,341
4,916
10,257
-8%
-15%
-23%
Analysis: The data shown here represents different design decisions using thermostat changes, shadings/blinds/overhangs, HVAC improvements and ventilation. Each scheme analyzed one aspect and the conclusion here is that using energy-star heating and cooling systems, an air retarding house wrap and high natural ventilation (by opening windows as needed) proved to have a total reduction of 23% versus as compared to the base case.
EXTRA CREDIT EXTRA CREDIT SCHEME [HIGH PERFORMANCE] Scheme # Base Case 1
Scheme Name Base Scheme High Performance
Cooling kBTU
Heating kBTU
Total kBTU
5,808
5,791
11,599
2,705
1,395
4,100
CLG Reduction
-53%
HTG Reduction
-76%
Total Reduction
-129%
CO2 production LBS
$ Energy cost/Year
5,316
$222
4,081
$165
Electricity in the West South Central U.S. is primarily produced by coal resulting in must higher CO2 emissions compared to states with cleaner electrical production. New Orleans electrical consumption compared to California will result in higher CO2 emissions for the same expenditure. Alternative electrical production is highly recommended.
CO2/kWh Comparison Total CO2 Production California 686 Louisiana 2,993 Wyoming 4,934
Analysis: We customized a scheme that was able to derive a total energy cost per year of $165, versus the base case of $222/year. The design is a 3-story camel-back dwelling that is raised off the floor (unoccupied space; to serve as a garage). It is enclosed by break-away walls that would keep the structure intact in case of a natural disaster or flooding. No modifications were made to the base case design in terms of: level of insulation (current energy code), windows (cleardouble pane low e-squared windows), roofs (medium-colored shingles, naturally ventilated), overhangs fixed all year long. Here is a list of the modifications made using a combination of different design variables to achieve a high-performance option on annual energy load: • Addition of 4 skylights dispersed (fixed) • Walls were 6-inch SIP’s • Fan-ventilated attic • Concrete floors, tiled with an unheated garage carport open to exterior • Infiltration and weather stripping: House wraps and sealed ducts added to default standard construction • Ventilation: high-natural ventilation (up to 20 air changes per hour; no fans) • Heating: Best available furnace • Cooling: Best available air conditioner
CONCLUSION HEED is a useful sustainability tool that is helpful for obtaining instantaneous results and calculations. There are different options to consider and HEED is able to make strong comparisons between energy performances. As architecture students, it is important to run several tests to determine the best results for your clients and the environment. The accuracy within HEED allows for the users to input their own U-values (from manufacturers) to customize their needs. In most of our comparisons, the results did not show a high level of variation, yet it is still valuable to know how to save money by simple architectural decisions made to the final outcome. The resources we used to aid us in our design decisions came from the Szokolaytables and the Kleissner Caretaker energy analysis data.
