Effect of chemical composition on VOC transfer through rotating heat exchangers

Rotating heat exchangers (RHEs) transfer contaminants from exhaust to supply air in several ways: with entrained air, through possible leakage around the wheel at the separation wall, and by condensation–evaporation or adsorption–desorption. Leakage from exhaust to supply was measured in several units using the tracer gas dilution technique, and found negligible if not absent in most cases. Leakage can be strongly reduced through a proper installation of the wheel, good maintenance of the gasket, proper installation of a purging sector, and maintaining a positive pressure differential from supply to exhaust duct at wheel level.