Air-source heat pumps

WLHP with Air Source Heat Pump Water Heater... 

Figure 17. WLHP with air source heat pump water heater...

Johnson, E.P. Air-source heat pump carbon footprints HFC impacts and comparison to other heat sources. Energy Policy. 2011,39,1369-1381. 

Air-Source Heat Pump - A type of heat pump that transfers heat from outdoor air to indoor air during the heating season, and works in reverse during the cooling season. 

Geothermal Heat Pump - A type of heat pump that uses the ground, ground water, or ponds as a heat source and heat sink, rather than outside air. Ground or water temperatures are more constant and are warmer in winter and cooler in summer than air temperatures. Geothermal heat pumps operate more efficiently than "conventional" or "air source" heat pumps. 

I When the temperature outside is 50 degrees Fahrenheit (F), the coefficient of performance (COP) of an air-source heat pump is approximately 3.3. When the temperature falls to 17 degrees F, the COP decreases to approximately 2.3, because the heat pump must perform more work to extract thermal energy from colder air. 

One limitation of air-source heat pump systems is the need for relatively mild winter temperatures, between 25 and 35 degrees F. Otherwise, supplemental heating may be required. One solution may be to include an electric heating device on the air outflow inside the building. 

Air source heat pump. Strangely, air source heat pumps currently require planning permission. However, the Government is currently consulting on allowing air source heat pumps as permitted development. So, check with the planning office of your local area before work commences. 

Air source heat pump. This system is not suitable for high-rise buildings. 

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