HOW DO HEAT PUMPS WORK?
Gas Absorption Heat Pumps
Gas Absorption/Adsorption Heat Pumps (GAHP) use a combination of a carrier and refrigerant which have a natural affinity. GAHP’s use heat to change the composition of the carrier & refrigerant solution and by changing the solution state (liquid-gas-liquid), heat equating to the latent heat of vaporisation is transferred.
The most common solution mixture is ammonia as the refrigerant and water as the carrier. The diagram below demonstrates the process.
Hence the GAHP process uses pressure differentials and temperature changes to move heat via change of state in a similar but different way to the vapour compression cycle.
Absorption devices mostly use naturally occurring chemicals for the solution mixture where the components mix volumetrically.
Adsorption devices often use a chemically manufactured absorbant refrigerant and the interaction is on the surface of the absorbant rather than within its volume.
