Energy conservation is a key component of global efforts to reduce dependence on fossil fuels. Building exhaust represents a significant opportunity to conserve energy, especially if the building has a large fresh air requirement. Colmac Coil Manufacturing, Colville, Wash., a manufacturer of process cooling equipment such as heat exchangers and coils, also provides heat pipe coils that can be used to capture and reuse energy that otherwise would be exhausted in space cooling applications.

The heat pipes, suitable for new buildings retrofits, serve as a passive device that transfers heat between the building exhaust and supply airstreams. For instance, during summer, when supply air temperatures are high and air-conditioned cool air is being exhausted, the refrigerant in the heat pipe absorbs heat from the supply airstream, effectively precooling it. The heat pipes can help reduce the building air-conditioning load by transferring this heat into the exhaust. In winter, this process is reversed and supply air is preheated.