Energy Recovery Ventilation is the process of exchanging the energy contained in normally exhausted building or space air and using it to treat the incoming outdoor Ventilation (architecture) air in residential and commercial HVAC systems. The benefit of using energy recovery is the ability to meet the ASHRAE ventilation & energy standards, while improving indoor air quality, and reducing total HVAC equipment capacity.
Air to Air exchange means the recovery device can transfer either sensible heat or total latent heat energy. A sensible only device will result in a change of the temperature only. A total enthalpic deice will result in a change of both the temperature and humidity within the air-stream.
The rotating wheel heat exchanger is composed of a rotating cylinder filled with an air permeable material resulting in a large surface area. The surface area is the medium for the sensible energy transfer. As the wheel rotates between the ventilation and exhaust air streams it picks up heat energy and releases it into the colder air stream. The driving force behind the exchange is the difference in temperatures between the opposing air streams which is also called the thermal gradient. Typical media used consists of polymer, aluminum, and synthetic fiber.
Fixed plate heat exchangers have no moving parts. Plates consist of alternating layers of plates that are separated and sealed. Typical flow is cross current and since the majority of plates are solid and non permeable, sensible only transfer is the result.
