Ductless Heat Pumps Myths, Modeling and Mesmerizing Material

Transcription

1 Ductless Heat Pumps Myths, Modeling and Mesmerizing Material

2 Myth: Ductless Heat Pumps don t work when it is cold out.

3 COP Capacity (1,000 Btu/h) Heating System Performance versus Outdoor Temperature DHP & Oil Boiler DHP & Oil Boiler 5.00 efficiency vs. temperature 30.0 capacity vs. Temperature Tout High Efficiency Cold Climate DHP COP Boiler COP Tout High Efficiency Cold Climate DHP Capacity Boiler Capacity Stnd DHP Capacity

4 Metered COP: VT Evaluation

5 Myth: Ductless heat pumps cost more than your oil system to run when its cold out.

6 $/MMBtu Heating System Costs v Outdoor Temperature $35.00 $30.00 $25.00 DHP & Oil Boiler cost vs. temperature Assumptions: $0.16/kWh $2.75/gallon of oil $20.00 $15.00 $10.00 $5.00 The cost of each unit of heat (btu) produced by a DHP varies as a function of outdoor temperature. $ Outdoor Temperature (Tout) Oil $/MMBtu High Efficiency Cold Climate DHP Stnd DHP $/MMBtu High efficiency ductless heat pumps cost less to operate than standard efficiency ductless heat pumps.

7 Temperature Time Series (hourly data) J a n u a r y F e b u r a r y M a r c h A p r i l M a y J u n e J u l y A u g u s t S e p t e m b e r O c t o b e r N o v e m b e r D e c e m b e r Axis Title Hour of the Year (starting at January 1st 0:00) Typical Meteorological Year Portland TMY3 Dry-bulb (F) Caribou TMY3 Dry-bulb (F) Bangor TMY3 Dry-bulb (F)

8 Typical Annual Hours Typical Annual Hours Binning of Temperature for Analysis Hours per Temperature Bin TMY and Modeled Heating hours Outdoor Temperature (Tout) Outdoor Temperature (Tout) Portland Bangor Caribou Caribou Caribou Gated heating

9 1,000 Btu/h 1e6 Btu Modeled Results: Heat Supplied High Efficiency Cold Climate DHP vs. Oil Boiler Heat Supplied "max"capacity kbtu/h capacity ASHP can deliver kbtu/h Tout Space Load kbtu/h ASHP actual delivered kbtu/h DHP heat supplied Tout Boiler heat supplied

10 $/MMBtu Annual Cost per Temperature Bin Modeled Results: Cost of Heating High Efficiency Cold Climate DHP vs. Oil Boiler $35.00 $30.00 $25.00 $20.00 $15.00 $10.00 $5.00 DHP & Oil Boiler cost vs. temperature Cost of Heat Supplied $80.00 $70.00 $60.00 $50.00 $40.00 $30.00 $20.00 $10.00 $ Tout Oil $/MMBtu High Efficiency Cold Climate DHP Stnd DHP $/MMBtu Tout 29 $ High Efficiency Cold Climate DHP Oil 'Make-Up' Only Central System

11 Annual Cost per Temperature Bin Annual Cost per Temperature Bin Modeled Results: Cost of Heating High Efficiency Cold Climate DHP vs. Standard Efficiency DHP Cost of Heat Supplied Cost of Heat Supplied $80.00 $80.00 $70.00 $70.00 $60.00 $60.00 $50.00 $50.00 $40.00 $40.00 $30.00 $30.00 $20.00 $20.00 $10.00 $ Tout $ Tout $- High Efficiency Cold Climate DHP Oil 'Make-Up' Only Central System Standard Efficiency DHP Blended Fuel "Make-Up' Only Central System Base-only annual operating cost $1,189 EE DHP + base annual operating cost $879 $ saved estimated $310 ASHP annual operating cost $650 Base-only annual operating cost $1,189 EE DHP + base annual operating cost $996 $ saved estimated $193 ASHP annual operating cost $271

12 Cost of Heat Delivered Cost of Heat Delivered Modeled Results: Cutover Cost of Heat Supplied Cost of Heat Supplied $60.00 $50.00 $3.50 $ Tout $40.00 $30.00 $20.00 $10.00 $ DHP Cost Oil 'Make-Up' Boiler Cost without DHP Tout $2.50 $2.00 $1.50 $1.00 $0.50 $ DHP Cost Oil 'Make-Up' Boiler Cost without DHP "lost" savings from not cutting off DHP $ 1.22

13 Heat Pump User Tips

14 Myth: You should turn down the temperature setting on your ductless heat pump at night and when you re not home.

15 National Renewable Energy Laboratory Case Study Comparison of two identical houses using DHP s as primary heat sources o o One home sets the thermostat based on comfort and occupancy One home sets the thermostat Long term Monitoring Short Term Comparison

16 Constant Set Point From:

17 On Off Operation

18 Setback and Constant Operation

19 Heat Pump User Tips

20 Myth: Ductless Heat Pumps will be used for air conditioning and break the grid in the summer.

21 DHP Reduce Air Conditioning s Impact on Peak Load Vermont published the evaluation of DHP s in November, 2017 The evaluation found that on average DHP s reduce cooling load:

22 Cooling (cont) The Vermont evaluation examine the AMI data before and after a DHP was installed. o Table reflects net savings:

23 Evaluations

24 Evaluation Results from Vermont and Massachusetts Massachusetts published the evaluation of DHP s in December, 2016 Vermont published the evaluation of DHP s in November, 2017 o Both studies found that the units were not being used as much as anticipated Vermont may be most comparable to Maine

25 Vermont DHP Usage

26 Integrated Thermostats

27 Integrated Thermostat 7 Homes with Mitsubishi DHP previously metered Honeywell Thermostat (VisionPRO 8000) integrated with DHP (through interface kit box PAC-US444CN-1) and Existing Central Heating System zone shared with DHP Remotely mounted wireless temperature sensor configured to control DHP and central system Droop between DHP and central system set to 2-3 deg F Before Thermostat Integration o 317 gallons of Oil offset with DHP After Thermostat Integration o 607 gallons of Oil offset with DHP

28 Lessons Learned

29 Lessons Learned DHP s can deliver significant benefits to customers The more they are used the higher the benefits DHP s operate differently that conventional systems Customer education and orientation is needed