An air-to-air heat recovery device transfers heat or enthalpy between two air streams, resulting in energy savings from reduced heating (or cooling) requirements.
A thermosiphon coil exchanger is a sealed system air-to-air heat recovery device that consists of an evaporator, a condenser, interconnecting piping, and an intermediate working fluid that is present in both liquid and vapor phases where the evaporator and condenser coils are installed independently in the ducts and are interconnected by the working fluid piping.