HVAC Quality Installation for ENERGY STAR Homes (For Version 3)

Transcription

1 HVAC Quality Installation for ENERGY STAR Homes (For Version 3) Questar Gas ThermWise Builder Program & Rocky Mountain Power wattsmart New Homes Program

2 ThermWise Builder Program & wattsmart New Homes Program Paid incentives on more than 10,000 homes Partner with builders to build better, more efficient homes Supports energy-efficient improvements beyond Utah building code Works with trade and program allies from preconstruction through final verification Offers builders and program allies marketing and training assistance and financial incentives

3 ENERGY STAR Version 3 Tighter Standards Increased emphasis on HVAC installation Whole Home Approach Better, More Sustainable Construction Surpasses Rapidly Changing Building Codes

4 Steps to Participate for HVAC Contractors Install HVAC systems according to ENERGY STAR guidelines & program requirements Register and receive training to become credentialed* Complete HVAC contractor checklist Submit HVAC contractor checklist to the HERS rater No special registration to work in program signup to receive program announcements from both programs *New to ENERGY STAR this year: HVAC Contractors must be credentialed. Currently offered by ACCA. For more information:

5 HVAC Contractor s Role for Version 3 Design and construct HVAC System in compliance with HVAC System Quality Installation Contractor Checklist Prepare and submit proper paperwork to Rater

6 Rater s Role for Version 3 Perform inspections and tests of home sufficient to complete Thermal Enclosure System checklist and HVAC System Quality Installation Rater checklist Model home from building plans and determine HERS Target Score Prepare and submit proper paperwork on behalf of the builder

7 ENERGY STAR Version 3: Checklists Checklists To earn the ENERGY STAR label, all homes must now be inspected for compliance with a new set of checklists. Two checklists are to be completed by the Home Energy Rater One checklist by the HVAC contractor One checklist by the builder

8 Implementation Schedule

9 HVAC Quality Installation For ENERGY STAR Version 3 Homes

10 Introductions Dennis Gray Nexant for Rocky Mountain Power Builders? HVAC Contractors? Energy Raters? Who else?

11 Objectives Understand goals of HVAC Quality Installation Know about HVAC-QI Credentialing Understand requirements of the ENERGY STAR HVAC-QI checklists Know what things need to be measured, and what things will be tested by energy rater

12 OVERVIEW

13 Why?

14 Some things obvious

15 Some things not obvious

16 The answer? HVAC Quality Installation Based on ACCA Standard 5 Credentialed HVAC contractors Checklists Third party verification

17 HVAC-QI Equipment Equipment installation Duct distribution System documentation/owner education You Should Get What You Paid For

18 ENERGY STAR HVAC-QI checklists Contactor checklist Rater checklist Developed by and for HVAC professionals

19 Contractor checklist overview Design (secs 1 2) Equipment selection (secs 3 5) Installation/startup (secs 7 12) Contractor signed document attesting that all applicable requirements have been met. Builder verified items option Rater performed testing option

20 Rater checklist overview Review of contractor checklist (section 1) Including load calcs, AHRI certificate, and balance report Inspections and testing (other sections) Third party verification of HVAC system installed and operating per program requirements. Signed by rater.

21 CHECKLISTS IN DETAIL

22 Contractor checklist section 1 Ventilation system installed per ASHRAE requirements Will look at all aspects of this section in next training session

23 Contractor Checklist Section 2 Load calculations Equipment Selection Duct design

24 Load calc considerations Correct design conditions Accurate areas and U values of envelope No added Safety Factors (J is the safe way)

25 Design conditions Design conditions are NOT the same as maximum and minimum temperatures recorded! Salt Lake City Winter design 11 F (99% of time warmer than this) Summer design 94 F (1% of time warmer than this)

26 Design conditions Use values per ACCA Manual J for location, or geographically closest location If alternate design conditions dictated by code or regulation, these would supersede.

27 Being checked by rater Correct design temperatures? Home orientation correct? Number of occupants correct (or NBR +1)? Conditioned floor area +/- 10% of actual? Window area +/- 10% of actual? Window SHGC within 0.1 of actual? Copy of load calculations submitted?

28 Winter load considerations

29 Summer load considerations

30 Load calc considerations Right sized equipment provides better comfort Right sized equipment is quieter Right sized equipment lasts longer with fewer warranty claims ENERGY STAR homes have about 30% less load than homes of the past your old thumb don t work no mo

31 Contractor Checklist Section 2 Load calculations Equipment Selection Duct design Or OEM recommendations

32 Equipment selection Need to use unit capacity values from OEM expanded performance data at design conditions Do not use AHRI nominal rating values! These will not be correct for Utah.

33 Dry climate selections 400 to 425 CFM per ton Dry-coil operation Almost all latent capacity will be converted to sensible capacity (i.e., sensible capacity will be nearly equal to unit total capacity)

34 Altitude correction Unit capacities are based on AHRI Conditions, which are at sea level (standard CFM) At high elevation air is less dense Sea level air: lb/cu-ft At 4300 feet: lb/cu-ft Correction factor = 0.075/0.067 = 1.12

35 Altitude affects To get AHRI capacity and leaving temperatures, actual CFM need to be 1.12 times catalog CFM OR If at catalog CFM (standard CFM) the temperature split will be about 1.12 times normal (may be limited by TXV)

36 Checked by rater Unit latent cooling capacity* exceeds design latent heat gain Unit sensible cooling capacity* exceeds design sensible heat gain Unit total capacity is 95% to 115% of design total heat gain (or next nominal size) * At actual design conditions, not AHRI conditions

37 Contractor Checklist Section 2 Load calculations Equipment Selection Duct design

38 Low airflow Poor system operation and loss of efficiency Possible coil frosting Poor air distribution and uneven temperatures in home

39 Proper airflow Good system efficiency (at SEER rating) Good air distribution Longer lasting equipment Happier homeowners

40 Duct design considerations Equipment capacity (CFM and static) Unit pressure drops (coil and MERV 6 filter) Diffuser and grille pressure drops Friction losses for duct runs Use equivalent length for all fittings and ells

41 MERV 6 filters 1 MERV 6 example filter

42 Install with filter box (with door)

43 Available static pressure Manufacturer's Blower Data Unit external static pressure (ESP) 0.75 IWC Device Pressure Losses DX cooling coil 0.28 IWC MERV 6 filter 0.18 IWC Supply register 0.03 IWC Return grille 0.03 IWC Subtotal 0.52 IWC Available Static Pressure for duct system flow (ESP-device losses) 0.23 IWC

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46 Plenum considerations

47 Duct TEL

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50 Register boot

51 Total effective length (TEL)

52 Manufacturer's Blower Data Unit external static pressure (ESP) 0.75 IWC 1000 CFM Device Pressure Losses DX cooling coil 0.28 IWC MERV 6 filter (1.20 x initial value) 0.18 IWC Supply register 0.03 IWC Return grille 0.03 IWC Subtotal 0.52 IWC Available Static Pressure for duct system flow (ESP-device losses) 0.23 IWC Total Equivalent Length (TEL) Supply duct TEL 255 Ft Return duct TEL 120 Ft Total 375 Ft Friction Rate Design Value Available static pressure / 100' of TEL PD/100' FR = ASP x 100 / TEL

53 Size ducts based on calculated friction rate (& with flow 900 FPM) Example 125 CFM takeoff (#6) FR > 7 dia duct Flow Friction

54 Size ducts based on calculated friction rate (& with flow 900 FPM) Example 1000 CFM main supply FR > 28 x 8 or 22 x 10

55 Pressure balanced Applies to all bedrooms 1 sq in of free area per CFM of transfer grille, jump duct, return duct, or door undercut (combined) Or tested by rater at 3 Pa (0.012 iwc) pressure difference across closed bedroom door

56 In-door transfer grille

57 Wall transfer grille

58 Jumper duct

59 Airflow facts 70% of home air conditioners have inadequate airflow Average home air conditioner airflow is 20% below manufacturer s recommended level (i.e., average of 320 CFM versus 400 CFM)

60 Duct design software

61 HVAC CONTRACTOR TESTS

62 Refrigerant tests Note that RMP rebates require startup record in all cases (if too cold, need to wait for warm weather) All section 6 measurements required If subcooling, +/- 3 F If superheat, +/- 5 F

63 Electrical measurements Blower fan amp & volts Condensing unit amp & volts

64 Air flow tests Airflow at evaporator (CFM) Return duct static pressure (IWC) Supply duct static pressure (IWC) Air flow, +/- 15% of system design value

65 Air balance Room by room airflow Balance dampers at main trunk (footnote 23) +/- 20% or 25 CFM Written balance report required submit to rater

66 Misc (sections 11 & 12) Operating and safety controls per OEM requirements Drain pan, piped to conspicuous point of disposal

67 Credentialed HVAC contractor Required for ENERGY STAR v3 homes By ACCA ACCA Quality Assured (QA) program Credentialed contractors show on list by ACCA

68 Third party verification of HVAC Quality Installation RATER CHECKLIST (CONTINUED ON PDF #2 OF HVAC QUALITY INSTALLATION PRESENTATION)