Heat pumps, air conditioning and refrigeration
Machines that move heat from cold to hot places, using a compressor.
Conversion and use · Conversion devices · No. 104
- Conversion and use
A heat pump delivers about four units of heat for every unit of electricity, by moving warmth that is already outside.
Chart: Illustration: Heat pumps, air conditioning and refrigeration
Where it comes from
Chart: Map of where it comes from
A refrigerant boils at low temperature, soaking up outdoor heat even on cold days; a compressor squeezes it hot enough to warm a home.
Three things to know
- The smaller the temperature lift, the better: the ideal COP is about 8.8 from 0 C air to 35 C underfloor water (calculated).
- Heat pumps save households about USD 300 a year in the US to USD 900 in Europe against fossil heating (2022).
- Industrial units can already deliver about 150 C, and machines above 160 C are expected commercially by 2027.
The journey
- 1 Outside heatFrom air, ground or water
- 2 EvaporatorRefrigerant boils, soaking up that heat
- 3 CompressorSqueezes vapour, raising its temperature
- 4 CondenserReleases heat into rooms or water
- 5 Expansion valveCools refrigerant to start again