What is a heat recovery ventilator and how it works?

Definition
A heat recovery ventilator,also know as HRV, heat exchanger, air exchanger, or air-to-air heat exchanger,is a type of mechanical equipment that features a heat exchanger combined with a ventilation system for providing controlled ventilation into a building.A heat recovery ventilator brings in fresh air from the outside, preheats the incoming air during the winter and precools the incoming air during the summer. It can maintain high indoor air quality without excessive additional energy costs.

How a Heat Recovery Ventilator Works?
As shown in the diagram below, a heat recovery ventilator (HRV) consists of two separate air handling systems – one collects and exhausts stale indoor air; the other draws in outdoor air and distributes it throughout the home.

Components of a Heat Recovery Ventilator

Heat Recovery
At the core of an HRV is the heat transfer module. Both the exhaust and outdoor air streams pass through the module, and the heat from the exhaust air is used to pre-heat the outdoor air stream. Only the heat is transferred; the two air streams remain physically separate. Typically, an HRV is able to recover 70 to 80 percent of the heat from the exhaust air and transfer it to the incoming air. This dramatically reduces the energy needed to heat outdoor air to a comfortable temperature.

Public Acceptance
This equipment can easily tie into the HVAC system. It enhances the quality of the home environment. But now there is very little awareness of this type of equipment. When understood, it is generally regarded favorably by people interested in new energy efficient homes and indoor air quality.

Date：2010-11-5