Air Source Heat Pumps - TheirPerformance, Issues and Potential

in the NorthDoug CanePrincipal

Caneta Research Inc

Northern Energy Solutions ConferenceFebruary 16, 2010

Scope of Presentation• Use of air source heat pumps in Northern climates.• Do’s and don’ts of heat pump installations.• What the latest cold climate designs have to offer

in terms of performance.• Compare climate of Whitehorse to that of Ottawa.• Cost benefit results for latest cold climate designs

in residential applications in Whitehorse will bepresented.

• conclude by identifying the advantages anddrawbacks of such systems.

Dos and Don’ts of Heat PumpInstallation

Heat pump installation can be divided into:

• Outdoor unit

• Indoor unit

• System start-up/turnover

• Homeowner instruction

Outdoor UnitLocation of Outdoor Unit:• site unit where prevailing winds will not cause snow drifts or interfere with defrosting.

• avoid locations between houses - snow drifting and noise can be problems.

• locate unit to ensure good service access.

• don’t locate under roof drip lines or where two roof slopes create gutter, unless eave-troughs are used

Outdoor Unit

Outdoor Unit

Outdoor Unit

Outdoor Unit

Outdoor Unit

Outdoor Unit• elevate above expected snow accumulations on suitably constructed frame with due regard to defrost water drainage.

• keep outside unit away from walls, fences, other surfaces which could reduce airflow or cause recirculation.

Outdoor Unit

Outdoor Unit

Indoor Unit Installation• use indoor coil that matches outdoor unit and furnace blower CFM capability.• set airflow to 400 CFM per rated ton.• install condensate drain for indoor coil that complies with manufacturer and local codes.• ensure air filter is installed and clean.• tape or seal all exposed plenum, air duct joints, seams and any penetrations to minimize supply air leakage.

System Start-up and Turnover• system start-up shall be done in strict accordance with procedures recommended by manufacturer.• heat pump should have comprehensive instructions, and documentation on equipment installation, electrical requirements, troubleshooting, O&M requirements, warranty (duration, parts and labour coverage).• contractor should keep installation records to facilitate future servicing; respond to warranty claims and rectify problems without delay.

Homeowner Instructions• make purchaser aware of benefits of upgrading building insulation/windows etc. to meet or exceed current Yukon requirements.

• turn over documentation to homeowner and instruct on differences from other heating systems, settings of thermostats, proper service and maintenance, and how to operate thermostats (including programming where applicable).

Examples of Cold Climate Designs

Acadia

York YZH

Mitsubishi Mr Slim

Acadia

Acadia Features

• Two compressors - Bristol Twin Single andbooster compressor

• HSPF: 9.33; COP@17ºF: 2.5; COP@0ºF: 2.3• Heating Capacity@17ºF: 43,500 Btu/hr• Heating Capacity@0ºF: 35,000 Btu/hr• six modes of operation are possible

York YZH

York YZH Features• One of most efficient units in AHRI Directory• HSPF: 10.0; SEER: 18.0; COP @ 17ºF: 3.0;

COP @ 10ºF: 2.7• Heating Capacity: 22,500 Btu/hr @ 17ºF;

19,300 Btu/hr @ 10ºF• Twin Single Compressor (1 and 2 cylinder

operation)• Microprocessor controls with demand defrost• matched to variable-speed (ECM) air handler or

furnace

Mitsubishi Mr Slim

Mitsubishi Features

• COP @ 17 ºF: 2.4; COP @ 0ºF: 2.0• the 2 ton unit has a heating capacity of

14,540 Btu/h @ 17ºF and 8,930 Btu/h @ 0ºF

COP and Heating Capacity vs Outdoor Temperature for Acadia Heat Pump

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

-15 -5 5 15 25 35 45 55

Outdoor Temperature (°F)

CO

P

0

10

20

30

40

50

60

70

Hea

ting

Cap

acity

(kbt

u/h)

COP Cold Climate Heating Capacity Cold Climate

COP and Heating Capacity vs Outdoor Temperature for York YZH

0.00

0.50

1.001.50

2.00

2.50

3.003.50

4.00

4.50

-15 -5 5 15 25 35 45 55

Outdoor Temperature (°F)

CO

P

0

5

1015

20

25

3035

40

45

Hea

ting

Cap

acity

(kbt

u/h)

COP Conventional Heating Capacity Conventional

COP and Heating Capacity vs Outdoor Temperature for Mitsubishi Mr Slim

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

-15 -5 5 15 25 35 45 55

Outdoor Temperature (°F)

CO

P

0

5

10

15

20

25

30

Hea

ting

Cap

acity

(kbt

u/h)

COP Mini Split Heating Capacity Mini Split

Comparison of Ottawa and Whitehorse Weather Data

0

20

40

60

80

100

120

140

160

180

-60 -40 -20 0 20 40 60 80 100

Outdoor Air Drybulb Temperature (°F)

Num

ber o

f Hou

rs a

t Tem

pera

ture

Trendline for Ottawa Data

Trendline for Whitehorse Data

Yukon Energy Prices

• Electricity: 12.4 ¢/kWh• Heating Oil: $1.07/litre (Dawson)• Heating Oil: $1.01/litre (Whitehorse)

Base Case Annual Heating Costs1800 ft2

• Oil Furnace - SuperGreen: $2,596• Oil Furnace - 2x4: $5,524

Heat Pump Installed Costs

• Acadia - 3 ton: $20,100

• York YZH - 4 ton: $11,075

• Mitsubishi - 1.5 ton: $5,665

Acadia Payback Compared to Oil

0

5

10

15

20

25

30

35

0 2,000 4,000 6,000 8,000 10,000

Heating Energy Cost Per Year

Sim

ple

Payb

ack

(yea

rs)

2 ton 3 ton 4 ton

York Payback Compared to Oil

0.00

5.00

10.00

15.00

20.00

25.00

0 2,000 4,000 6,000 8,000 10,000

Heating Energy Cost Per Year

Sim

ple

Payb

ack

(yea

rs)

3 ton 4 ton 5 ton

Mitsubishi Payback Compared to Oil

0

2

4

6

8

10

12

14

16

0 2,000 4,000 6,000 8,000 10,000

Heating Energy Cost Per Year

Sim

ple

Payb

ack

(yea

rs) 1.0 ton 1.5 ton 2.0 ton

Conclusions• Cold climate designs promise more heating

capacity and higher efficiency at lowtemperatures.

• Payback periods look attractive at higherlevels of consumption.

• Longer hours of operation may impact onreliability and compressor life. Moreoperating experience is needed.

• Limited number of cold climate designs atpresent.