Water To Water Heat Pump

Abstract

Air-to-air heat pumps do have their limitations when it comes to space heating. The colder the outside air the less heat each pound of refrigerant picks up as it circulates through the system. Heating capacity, as well as efficiency, decreases as outdoor temperatures fall. This inescapable constraint of thermodynamics often requires air- source heat pumps to be equipped with supplemental heat sources to handle peak loads in cold northern climates. If that supplemental heat is provided by electric resistance elements, the overall efficiency of the system can be reduced substantially. Air-to-air heat pumps also require a defrost cycle to remove frost from the outdoor heat exchanger during cold weather. Hot refrigerant gas is periodically recirculated in the outdoor coil to melt the frost. The energy used to defrost also lowers overall system efficiency.