Performance analysis of heat and energy recovery ventilators using exergy analysis and nonequilibrium thermodynamics

We illustrate the concepts by applying the analysis to a heat recovery ventilator (HRV) and to a structurally similar membrane energy recovery ventilator (MERV) that can exchange both heat and moisture. We show how the exergy efficiency can be used to identify the range of operating conditions for which the recovery ventilator is not beneficial as the energy cost is greater than the energy recovery. This is not trivial using traditional performance parameters, yet it is a natural outcome of exergy analysis. In addition, we identify the mechanism by which work potential is lost, which can help the eventual optimization of both the recovery process and the auxiliary systems present in ventilation systems.