Net Zero Homes and Energy Efficient Mini Split Systems. Greg Davenport Sam Beeson

Transcription

1 Net Zero Homes and Energy Efficient Mini Split Systems Greg Davenport Sam Beeson

2 Part 1 Part 4 Part 2 Part 3 Greenstone Why Net Net Zero Zero Homes Demonstration are coming Home Why faster mini than split you systems realize are Design and application strategies a great A Washington choice for energy efficient homes with mini State split production systems builder begins the journey to Net Zero years before it is required by code

3 Who are you and what do you do when you are not here? How How many of you are builders, HVAC contractors, weatherization How many How many many of of you of you program implementers, have you believe used work utility a on that all residential builders in CA employees, Ductless multi-family Heat housing energy Pump raters? system projects? before? will be ready to go Net Zero in 2020?

4 Where are you from? Cold climates? Humid climates?

5 How many of you work on homes with electric resistance heat?

6 How many of you work on homes with window hung A/C units? Airtight and great R value???

7 Anybody working with PTHP s? EER Electric resistance strip heat Heat pump not designed for cold climate operation Can be noisy

8 Part 1 Why Net Zero Homes are coming faster than you realize

9 High performance home formula Low load envelope (High R value and low air infiltration) Solar or other renewable energy source High Performance Home Energy efficient HVAC system Energy efficient lighting and appliances Energy efficient hot water system

10 Net Zero Homes defined A net zero home is a high efficiency home. Net zero homes have on site power generation - most commonly PV (photovoltaic) solar panels. Net zero homes are designed to produce as much energy as they consume on an annual basis. Net zero homes utilize either net metering and/or battery storage systems.

11 Z e r o E n e r g y U n r e a d y!

12 A Net Zero Home

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14 We are on the tipping point of Net Zero Home building

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17 What about electric resistance heat? Electric resistance heat is a very inefficient source of heat IECC and state building codes are pushing builders towards mini-split VRF systems

18 In 2020 California state will require all residential new construction to be Net Zero

19 Utility bills The Second Mortgage that people rarely consider when buying a home

20 Hypothetical Value Proposition Code built $300,000 80% LTV - $240,000 loan 30 year 3.75% Same house with high performance $312,000 80% LTV - $249,600 loan 30 year 3.75% Same house with high performance and solar $328,000 80% LTV - $262,400 loan 30 year 3.75% Monthly payment = $1,111 Monthly payment = $1,156 Monthly payment = $1,215 Monthly utility bills = $82 Monthly utility bills = $58 Monthly utility bills = $-6 Total monthly payment = $1,193 Total monthly payment = $1,214 Total monthly payment = $1,209

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27 Ductless Heat Pumps are used all over the world They have been around for over 35 years

28 Modern American home or Hong Kong apartment?

29 Part 2 Why mini split systems are a great choice for energy efficient homes

30 The benefits of a mini split VRF system - Energy Efficiency up to 33 SEER /13 HSPF - Provides heating and cooling - Zoned for improved comfort and energy savings - Design flexibility reduces or eliminates ductwork - Improves indoor air quality

31 More benefits of a mini split VRF system - May qualify for utility rebates and/or high performance home specification programs - Comfort and indoor air quality are tangible qualities that a homeowner wants - Many mini split systems are ENERGY STAR qualified to ensure high quality and performance

32 Refrigerant is almost 10 times more efficient than water at heat transfer Refrigerant is 177 times more efficient than air at heat transfer

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38 Mini Split split systems are proven technology and utilities offer incentives

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43 Part 3 Design and application strategies with mini split systems

44 Do a room by room load calc every time Wrightsoft, Adtek, Acculoads, EnergyGauge, or SpecPro Do a Manual D calculation every time if you have ducts Elite DuctSize, Wrightsoft Right-D, or Ductulator Don t oversize systems Can cause poor performance and increases system expense needlessly. Many building codes and High Performance Home Programs now restrict over-sizing systems. Consider using well designed airshare or transfer system when possible Design it right and prevent comfort problems Tight high performance homes change the humidity dynamic Design to manage humidity if needed Use and HRV or ERV whenever possible

45 Built Right Homes builds the identical home in the same subdivision on two different lots. The two homes have different load calculations. How could this be? Different building orientation changes the load calculation.

46 What are the components of a Manual J heating/cooling load calculation? - Local design temperature (and altitude) - Local humidity - Building orientation - Envelope (wall, floor, and ceiling) R values and dimensions - Window and door U values and dimensions - Window SHGC (solar heat gain coefficient) - Air infiltration target ACH50 What about Shading?

47 Audience Question For a simple DHP installation of one wall hung head and compressor, about how long does it take an experienced HVAC contractor?

48 SIZING DUCTLESS HEAT PUMPS Size to meet the load of the zone(s) at design conditions When sizing, the minimum capacity is nearly as important as the maximum capacity When the house load drops below minimum capacity, performance drops from severe short-cycling A look at the max/min capacity at 47 F can be an indicator of how the unit will perform in these conditions We call this the unit s turn-down ratio. It varies greatly by model. Look for a unit with at least a 4:1 ratio or higher between its maximum and minimum capacity at 47 F

49 Manufacturer's Stated Heating Capacity at 47 deg F (Btu/hr) SIZING DUCTLESS HEAT PUMPS 25,000 Comparison of Nominal 1-ton DHP Models "Rated" Capacity 20,000 15,000 10,000 5,000 -

50 Manufacturer's Stated Heating Capacity at 47 deg F (Btu/hr) SIZING DUCTLESS HEAT PUMPS 40,000 35,000 30,000 25,000 20,000 15,000 10,000 5,000 - Comparison of Nominal 2-ton DHP Models "Rated" Capacity

51 BOISE DHP, LOW OUTPUT SIZING DHP Sizing Design load:24 Nom Size 24K H o u r s K low output i n T e m p K low output 3300 hrs hrs B i n 0 < to to to to to to to to to 59 0 BTU/Hr Hours in bin Boise

52 SEATTLE DHP, LOW OUTPUT SIZING DHP Sizing K low output 3K low output Design load:15 K@27F: Nom size 18K 4375 hrs 2810 hrs H o u r s i n T e m p B i n 0 < to to to to to to to to to 59 0 BTU/Hr Hours in bin Seattle

53 DHP SYSTEM DESIGN Considerations: How to heat and cool remote rooms Home geometry and floor plan influence heat distribution Backup heat in bedrooms may be a good idea

54 DHP SYSTEM DESIGN Orient heads to take advantage of throw and mixing o Place in largest, most open areas o Orient to blow down central hallways In rooms with high ceilings, place DHP < 8 off the floor to minimize stratification effects

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58 Design Flexibility

59 Multi position air handlers for retrofit to central systems

60 ROUGH IN OF VRF SYSTEM

61 MILLS RESIDENCE- GA

62 MILLS RESIDENCE- GA Mitsubishi chosen for high efficiency, flexibility and smaller capacities 2 SEZ units were used to move air to most of the rooms 1 wall hung was used to add personalized control to the master suite 1 transfer fan was used to direct air from the master bedroom to the mater bath Cost of systems only slightly higher than traditional system with 16 seer and ductwork. Less overall ductwork/ ductloss, easier installation and better zoning/comfort capacity. Ductwork was easier to keep inside the thermal envelop resulting higher efficiency

63 MILLS RESIDENCE- GA Transfer fan GE-09 2-SEZ s

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78 INDOOR AIR QUALITY AND VENTILATION STRATEGIES The Problem Homes are getting tighter and tighter People spend 90% of the time indoors Chemicals, allergens, and mold detrimentally affect health and happiness The solution Keep the chemicals out of the living space Less toxic building materials Ventilate when you cook Supply fresh air/exhaust the bad air ASHRAE 62.2 Consider using an HRV/ERV to improve IAQ and energy efficiency Reduce space conditioning ductwork when possible Good filtration

79 Habitat for Humanity Project

80 HOMES AT THE WOODS

81 WA STATE ENERGY CODE CHANGE TEXT 81

82 82 KEY RESEARCH QUESTIONS Comparing a hybrid DHP-ER system to an all electric resistance heating system What are the average annual electricity and bill savings? What are the estimated total and incremental installed costs? What is the expected life cycle impacts? Are participants at least as comfortable?

83 HOW DHP HYBRID DISPLACEMENT WORKS Ideal alternative to electric resistance zonal heated homes Zonal Electric Reduces heating bills by displacing a large share of zonal electric heat DHP Hybrid Displacement DHP installed in the main living area

84 STUDY OF ENERGY USE USING SWITCH-BACK DESIGN Compare electrical use of hybrid DHP/ER heat VS all ER heat in new construction FOR THE STUDY - Common area contains both DHP and ER heat switched between the two weekly Switching schedule staggered between homes Each home to act as its own control over a range of temperatures Homeowners are given choice at end of study which heating system they would like to keep 84

85 NEW HABITAT HOMES Specifications Continuous R-15 under slab insulation R-21 + R5 exterior walls R-49 ceiling U-.28 windows Energy Star certified lighting Continuous heat recovery ventilation Hybrid ductless heat pump / electric resistance heating

86 SAVINGS ANALYSIS (HEATING)

87 HYBRID DHP SYSTEM SAVINGS ESTIMATES (KWH/FT 2 ) Energy Used (kwh/ft 2 ) Hybrid DHP-ER All-ER Savings Heating Season Cooling Season (Jul & Aug) Total % savings over all-er system 1280 ft2 (typical) x 2.19 = 2803 kwh/year 2803 kwh/year x $0.0853/kWh =$239/year

88 88 ECONOMIC DATA & ASSUMPTIONS Item All-ER Hybrid DHP-ER Change Heating System Cost $321 $2,746 $2,425 Replacement Cycle 30 Years 18 Years Maintenance Allowance $0 $11/Year $11/Year Annual kwh Use 6,027 3,221-2,806 Annual Utility Bill $524 $280 - $244 First Year Finance Cost $15 $126 $111

89 HOMEOWNER ORIENTATION

90 HOMEOWNER EDUCATION Leave interior doors open Clean filters Don t make big changes in the set points The best system in the world does nothing if it isn t used properly Homeowners must be educated on the operation of systems in their homes

91 OCCUPANT SURVEY PERCEPTIONS On performance: How did [system] perform in heating your common living area to a comfortable temperature? 6 homeowners gave the DHP a higher rating than ER 4 homeowners rated them the same Only 1 homeowner rated the ER higher When asked Which system they would choose at end of study? 10 out of 11 have already decided to keep DHP 1 preferred DHP but wants to see energy savings first Many reasons why DHP is preferred, including: Heating performance, cooling function, furniture placement & curtain use, fire hazard & child safety concerns with baseboards

92 Westgate Apartments Multi-family Retrofit Originally built in buildings 380 One and two bed apartments Old PTAC units were failing and needed to be replaced They were not keeping tenants comfortable They were noisy Maintenance staff was spending a lot of time repairing the old units Old units were not energy efficient

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94 Ameren Illinois ActOnEnergy Multi-family Program provided technical assistance and rebates Insulation and airsealing required for program participation 44 year old building had no room for ducts ductless was the only practical solution Only one day required to install New system in each unit

95 Energy used went down by 33% In vacant units Tennant comfort increased significantly because each room has air handler New systems much quieter than old PTAC units No comfort complaints from tennants Maintenance staff no longer wastes time fixing old PTACs

96 Massachusetts/Rhode Island Multi-family weatherization study DHP displacement of electric resistance

97 Multi-family projects Commercial or residential VRF systems?

98 Hi Rise Multi-Family Projects Centralized or In-suite systems

99 Part 4 Greenstone Net Zero Demonstration Home A Washington State production builder begins the journey to Net Zero years before it is required by code

100 Wolfe Penn Net Zero Demonstration Home

101 Anderson Consulting provided energy modeling, program certification testing, and building science consulting for project

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103 Reference home is based on 2006 IECC no consideration for size given WA State Code built home/2015 IECC approximately 55 Greenstone Net Zero Demonstration Home before solar approximately 42 Greenstone Net Zero Demonstration Home with solar Minus 6

104 High performance shell

105 Energy efficient heating and cooling

106 Room by room heating and cooling load calculation Manual J Heating load 21,479 BTU Cooling load 13,875 BTU Bedroom 3 only 1,709 BTU

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108 High performance Lifebreath Fresh Air system Heat recovery whole home ventilation fan plus whole home filter for healthy indoor air quality

109 How a HRV fresh air ventilation system works

110 Whole home air filter for healthy indoor air quality

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112 Rheem high efficiency heat pump hot water system COP

113 ENERGY STAR lighting and appliances

114 WaterSense plumbing fixtures save water and energy Low toxicity building materials improve indoor air quality and health

115 Photovoltaic solar panels should produce enough energy to power home on an annual basis

116 This house is so energy efficient it only needs 19 solar panels to produce all the electricity to be net zero

117 Demonstration project will be monitored to test Comfort transfer fan performance IAQ Energy use Monitoring data will be shared by builder, Mitsubishi, Lifebreath, and home buyer

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122 HVAC Academy Awards Mini splits are faster to install = lower labor costs

123 HVAC Academy Awards Low load homes and value engineered DHP systems have comparable costs to traditional systems

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125 Spokane HBA Fall Home Tour

126 Tracking incremental costs Approximately $20,000 for solar system Approximately $12,000 to go from code built to Zero Energy Ready These Used costs made do not in Washington include monitoring solar panels expenses Costs would be lower if builder repeated could have used other solar panels and reduced cost

127 8-12 MPG Change is coming!