Heat pumps are energy-efficient heating and cooling systems that operate according to thermodynamic principles, specifically heat transfer. Heat pumps use refrigeration cycles to move heat from colder environments into warmer ones – providing an energy-saving way of heating homes efficiently. Heat pumps use a closed-loop refrigeration cycle consisting of four main components, such as an evaporator, compressor, condenser and expansion valve to transfer heat efficiently. Heat pumps can be used for both heating and cooling.
Start at the outdoor unit of your heat pump where an evaporator coil contains refrigerant fluid – typically hydrofluorocarbon (HFC), with a low boiling point – that absorbs heat from outside air as it passes over its coil. As air from outside flows over this coil, heat absorbs into it causing its refrigerant to absorb more and more of this outdoor heat until finally, its refrigerant evaporates resulting in low-pressure, low-temperature gas that leaves behind only heat at its place.
Low-pressure refrigerant gas is then drawn into a compressor, typically located inside an indoor unit, for increased pressure and temperature levels of its refrigerant gas, thus producing high-pressure, high-temperature refrigerant.
High-pressure and high-temperature gas is then sent to a condenser coil located inside your home, where refrigerant releases any heat absorbed from outdoor air it has absorbed and transfers it directly back into indoor air circulating over its coil. As heat escapes from its source, refrigerant begins condensing back into liquid form – eventually returning back into circulation within your home as you breathe it in!
High-pressure liquid refrigerant passes through an expansion valve to quickly reduce its pressure and temperature, turning into low-pressure, low-temperature liquid-gas mixture that’s ready to start the cycle again. Heat drawn from outdoor air is now being released inside your home to heat it, creating warm indoor air that fans or forced-air systems distribute throughout your living spaces. Hydronic and radiant systems also utilize this heat, but instead use it to warm water or a heat transfer fluid which then circulates through pipes or radiators and into your living spaces – heating your entire living area simultaneously!
Additionally, heat pumps can also serve to cool your home during the summer. A reversing valve allows the system to change the direction of refrigerant flow by extracting heat from indoor air and dissipating it outside – thus cooling your home.