Specific heats determine the storage of thermal energy
Air – 0.018 Btu/ft3, Water – 62.42 Btu/ft3, or 3472 times higher
Heat pumping works through phase change of the refrigerant; boiling
to gas or condensing to liquid
Typical refrigerants have boiling points of -40°F
When the refrigerant is compressed, heat is released and it liquefies;
when decompressed through an expansion valve, it cools as it
changes to a gas
Reversing the direction of refrigerant travel through the system
changes operation from an air conditioner to a heat pump