Performance of Rotary Heat and Mass Exchangers

Abstract

Rotary regenerative heat and mass exchangers (enthalpy exchangers) can reduce air-conditioning costs in ventilated buildings by recovering energy from the exhaust air and transferring it to the supply air stream. In this study the adsorption isotherms of a desiccant used in a commercially available heat and mass exchanger are measured. The isotherms and other property data are incorporated into the program MOSHMX which numerically solves the governing equations for combined heat and mass transfer. The numerical results are then used to develop a computationally simple model for determining the performance of a specific enthalpy exchanger as a function of the air inlet conditions and the matrix rotation speed. The numerical results agree with the catalog information provided by the manufacturer. The enthalpy exchanger model is used in the transient simulation program TRNSYS to estimate the annual performance. Integrated energy savings (heating and cooling) are determined for a commercial application (a 200...