Raising the Bar: A Comparison Study of Iowa s Current and Proposed Energy Code

Transcription

1 Raising the Bar: A Comparison Study of Iowa s Current and Proposed Energy Code Julia Gauthier, LEED AP BD+C Jeanne Huntsman, AIA, LEED Green Associate The Weidt Group

2 Raising the Bar Special statements Not intended to be a comprehensive evaluation of how to meet new code requirements Study inspired by impact of code changes on CNC program projects Views expressed do not represent the state of Iowa, code officials, or the utilities directly We are not code officials This study was completed in May 2012

3 Agenda The new code Analysis and results Building type results Summary Conclusion

4 Raising the Bar Code Comparison 2009 IECC (ASHRAE ) change to 2012 IECC (ASHRAE )

5 The New Code Details of updates for ASHRAE Climate zone 5A

6 The New Code Summary of updates for ASHRAE Building envelope roof/wall insulation skylights Heating, ventilation & air conditioning equipment control required equipment required efficiencies Service hot water Power/plug load control Lighting controls automatic daylighting controls lighting design Motor efficiency no change (except metal buildings) major change major change major change major change no changes major change major change major change varies by space type minor change

7 Building Envelope Summary of Changes Design Feature Increased insulation for a metal building Skylights The Change Code level assembly insulation values increased from R-8.8 to R-14.5 for walls and R-15.4 to R-18.2 for roofs Given certain criteria a minimum skylight fenestration area is required

8 Building Envelope A closer look minimum skylight fenestration area A skylight is required in any enclosed space in a building that is four stories or less and: greater than 5,000 sq. ft. directly under a roof with a ceiling height over 15 ft is one of the following spaces: Example 5,000 sq. ft. gymnasium in a two story high school with a ceiling height of 20 feet Skylights required? ASHRAE : NO ASHRAE : YES office lobby Atrium distribution / sorting area convention center nonrefrigerated warehouse or storage automotive service gymnasium / exercise center manufacturing retail concourse transportation workshop

9 HVAC Summary of Changes Design Feature Enclosed parking garage ventilation Multi-zone variable air volume (VAV) system ventilation optimization control The Change CO sensor control will be required for garage ventilation fans appears to require occupancy sensor control of outside air to VAV boxes (further interpretation needed to fully determine impact) Hydronic variable flow systems Exhaust air energy recovery Kitchen/dining facilities Improved DX cooling efficiencies almost all pumping systems to will require variable speed control heat recovery requirements based on percent OA and total supply air (required addition of heat recovery to three of eight buildings studied) require increased control or heat recovery if exhausting more than 5,000 cfm Code level DX cooling efficiencies increased 5%-15% depending on the size and heating type

10 HVAC Summary of Changes (continued) Design Feature Variable Refrigerant Flow (VRF) Systems Water-to-water heat pumps Chiller performance Computer Room Unit The Change Code level efficiencies have been added. EER: 9.3 to 16.2 COP: 2.05 to 4.2 Code level efficiencies have been added. EER: 10.6 (water source) or 16.3 (groundwater) COP: 3.7 (water source) or 3.1 (groundwater) New emphasis on part-load performance, as well as a Path A and a Path B. Path A: lower full load, higher part load. Path B: higher full load, lower part load Code level efficiencies have been added. Utilizes a Sensible COP (SCOP). Differentiates downflow and upflow units

11 HVAC A closer look exhaust air energy recovery Exhaust air energy recovery required when the following conditions are met: Supply Air CFM Outside Air % > > > > > >0 > 80 Example Air handling system providing 6,000 CFM of supply air, 35% outside air Exhaust air energy recovery required? ASHRAE : NO ASHRAE : YES with at least 50% effectiveness

12 Service Hot Water and Power Summary of Changes Design Feature Service hot water No significant changes The Change Power Automatic plug load control, automatic receptacle control, at least 50% of all 125 volt, 15 and 20 ampere, receptacles in private offices, open offices and computer classrooms shall be controlled by an automatic control device

13 Lighting Summary of Changes Design Feature Lighting control Space control Parking garage lighting control Automatic daylighting controls for primary sidelighted areas The Change any automatic control device shall be manual on or only automatically on to 50% all controlled lighting shall have at least one control step between 30% and 70% in addition to all off, dual level switching is required parking garage lighting is required to have automatic control to reduce power of each luminaire by 30% when no activity is detected for 30 minutes when sidelighted area is equal to or exceeds 250 sf, the lamps must be controlled with a photosensor and contain at least one control step that is between 50% and 70% and another to no greater than 35%

14 Lighting Summary of Changes Design Feature Automatic daylighting controls for toplighting Lighting power densities using the space-by-space method Individual lighting power allowances for building exteriors The Change when the daylight area under the skylights or roof monitors exceeds 900 s.f., the lamps must be controlled with a photosensor and contain at least one control step that is between 50% and 70% and another to no greater than 35% reduced lighting power densities for most spaces. Incorporation of room cavity ratio (RCR), which allows for increased lighting power density allowances based on room geometry (unique per building, further study needed) reduced lighting power allowances for most exterior areas

15 Lighting A closer look automatic daylighting (side lighted) When primary sidelighted area in an enclosed space equals or exceeds 250 sf the lamps shall be controlled by at least one multi-level photocontrol. The multilevel photocontrol must reduce electric lighting in response to available light with at least one control step between 50% and 70% and another control step no greater than 35%. Example 100,000 sq. ft. office building with typical open office operation, open office has side lighted space greater than 250 sq. ft. Automatic stepped daylighting control required? ASHRAE : NO ASHRAE : YES two-step control

16 Analysis and Results Building type selection Sample of Iowa Commercial New Construction (CNC) program participants Alliant Energy, Black Hills Energy and MidAmerican Energy program participants

17 Analysis and Results Ten test buildings Type Heating Cooling Air Flow Bldg SF Middle/High School Gas boiler Air-cooled chiller Variable air volume 94,500 0 Garage SF Middle/High School Electric Boiler Water-loop heat pump Constant volume 94,500 0 College Classroom Gas boiler Water-cooled chiller Variable air volume 80,000 0 College Classroom District Heating District Cooling Variable air volume 80,000 0 Office Gas furnace Air-cooled DX Variable air volume 45,000 0 Office Electric Boiler Water-loop heat pump Constant volume 45,000 0 Multi-family Gas furnace Air-cooled DX Constant volume 60,000 0 Multi-family Electric boiler Water-loop heat pump Constant volume 60,000 0 Retail Gas furnace Air-cooled DX Constant volume 66,400 3,600 Transportation/ Public Works Gas furnace Air-cooled DX Constant volume 41, ,000

18 Analysis and Results Procedure Current Energy Code Created a current 2009 IECC energy model baseline for each building using the prescriptive path of ASHRAE New Energy Code Created a 2012 IECC energy code baselines incorporating building specific changes found in ASHRAE

19 Analysis and Results Results - total energy use in kbtu per square foot OLD kbtu/ sqft NEW kbtu/ sqft

20 Analysis and Results Results Annual Energy Costs Observations The weighted average of all sample buildings is 18% less energy when built to the new code Transportation/public works indicates the largest change (49%) due to more stringent controls of heated garages Multi-family is expected to use about the same as current code because new code does not impose many restrictions on residential buildings, test buildings did not have garages

21 Analysis and Results Results Annual Energy Costs $250,000 $200,000 $150,000 $100,000 $50,000 $0 OLD Cost NEW Cost

22 Analysis and Results Results Annual Energy Costs Observations Iowa average energy costs The weighted average of all sample buildings is 21% lower annual energy costs Transportation/public works has the largest reduction Multi-family has the smallest change in annual energy costs

23 Analysis and Results Building Type Results Middle/high school College classroom Office Multi-family Retail Transportation/public works

24 Analysis and Results Middle/High School (electric system) Building summary Heat source: electric boiler Cool source: water loop heat pump Airflow: constant volume Building area: 94,500 sq. ft. Primary space types: Classroom, gym

25 Analysis and Results Middle/High School (electric system) Skylights required in gym Two step automated daylighting required near windows and under skylights Occupancy sensor control of lights in most spaces Reduced lighting power densities VFDs on circulation pumps Exhaust air energy recovery kbtu therm kwh kw Energy Cost Old Code (today) ,410 2,720, $214,133 New Code ,410 2,184, $173,114 Difference , $41,019 Percent Change 18% 0% 20% 23% 19%

26 Analysis and Results College Classroom (gas system) Building summary Heat source: gas boiler Cool source: watercooled chiller Airflow: variable air volume Building area: 80,000 sq. ft. Primary space types: Classroom, laboratory, offices

27 Analysis and Results College Classroom (gas system) Two step automated daylighting required near windows ** Occupancy sensor control of lights in most spaces ** Reduced lighting power densities ** VFDs on circulation pumps Occupancy sensor control of plug load ** Contributes to increased gas usage kbtu therm kwh kw Energy Cost Old code (today) , , $70,370 New code , , $59,619 Difference 4.8-1, , $10,751 Percent Change 8% -9% 22% 14% 15%

28 Analysis and Results Office (gas system) Building summary Heat source: gas furnace Cool source: air-cooled DX Airflow: variable air volume Building area: 45,000 sq. ft. Primary space types: Open office, private office

29 Analysis and Results Office (gas system) Two step automated daylighting required near windows ** Occupancy sensor control of lights in most spaces ** Reduced lighting power densities ** Occupancy sensor control of plug load **Contributes to increased gas usage kbtu therm kwh kw Energy Cost Old code (today) , , $53,872 New code , , $46,315 Difference 4.9-1, , $7,557 Percent Change 6% -10% 22% 12% 14%

30 Analysis and Results Multi-Family (electric system) Building summary Heat source: electric Cool source: water loop heat pump Airflow: constant volume Building area: 60,000 sq. ft. Primary space types: Apartment No garage space

31 Analysis and Results Multi-Family (electric system) Least impacted building type studied Two step automated daylighting required near windows in non-residential Dual level switching of lights in non-residential areas Reduced lighting power densities in non-residential Occupancy sensor control of plug load Increased cooling efficiencies kbtu therm kwh kw Energy Cost Old Code (today) , , $83,729 New Code , , $82,182 Difference , $1,547 Percent Change 1% 0% 2% 2% 2%

32 Analysis and Results Retail (gas system) Building summary Heat source: gas furnace Cool source: air-cooled DX Airflow: constant volume Building area: 66,400 sq. ft. additional garage area: 3,600 sq. ft. Primary space types: Sales floor, auto maintenance

33 Analysis and Results Retail (gas system) Skylights required Two step automated daylighting required near windows and under skylights Reduced lighting power densities Exhaust air energy recovery required CO control of vehicle storage ventilation fans kbtu therm kwh kw Energy Cost Old Code , , $92,808 New Code , , $75,767 Difference , , $17,041 Percent Change 22% 29% 14% 16% 18%

34 Analysis and Results Transportation/Public Works (gas system) Building summary Heat source: gas furnace Cool source: air-cooled DX Airflow: constant volume Building area: 41,000 sq. ft. additional garage area: 108,800 sq. ft. Primary space types: Vehicle storage, offices

35 Analysis and Results Transportation/Public Works (gas system) Most impacted building type studied Skylights required Two step automated daylighting required by windows and under skylights Reduced lighting power densities Exhaust air energy recovery required CO control of vehicle storage ventilation fans kbtu therm kwh kw Energy Cost Old code (today) ,460 1,011, $222,985 New code , , $121,651 Difference , , $101,334 Percent Change 49% 53% 32% 29% 45%

36 Analysis and Results Summary The new code impacts different buildings differently Depending on the space types and system characteristics the code may play a more significant role in shaping the design Percent Change OLD to NEW Code kbtu/sf Energy Cost 49% 45% 18% 19% 15% 14% 8% 6% 1% 2% 22% 18%

37 Summary As expected, the new code 2012 IECC (ASHRAE ) raises the bar for a minimally code compliant building Implementation of the new code will reduce building energy usage by approximately 20% on average If the goal is increased energy reduction from current levels, the new energy code accomplishes the goal If the goal is increased energy reduction beyond the new code, additional steps will need to be taken

38 Summary So what does it all mean? It s not just a jumble of numbers and pulling out your hair!

39 Going Beyond Code Start early, consider the energy efficiency implications of decisions made during Pre- Design Massing Orientation Window/wall ratio Investigate several mechanical systems and life-cycle costs What was once cost-prohibitive may no longer be Expand upon the code requirements If the code says automatic daylight control required for 1,000 sf, can the design allow for 2,000 sf? If the code says 50% plug load must be controlled by occupancy sensors, can 75% be controlled? Use resources such as the Commerical New Construction program Continue to explore new technologies and best practices code changes have happened before and the design community always rises to the challenge

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41 Qualifications Commercial New Construction Program Iowa business utility customers New construction Additions Major renovations Generally over 5,000 sq. ft. Sufficient design schedule Available from Alliant Energy Black Hills Energy MidAmerican Energy Company Incentives for whole building performance Comparative information

42 CNC Program How to Enroll Now enroll online! energyassistance.twgi.com Learn more and link to online application Alliantenergy.com/newcon struction Contact account manager Contact The Weidt Group

43 Thank You