Comparison of various methods for evaluating the membrane-type total heat exchanger performance

Four methods are used to evaluate the performance of a membrane-type total heat exchanger, they are the numerical method with consideration of moisture adsorption heat, the numerical method with no consideration of that heat, the effectiveness-NTU method with consideration of that heat, and the effectiveness-NTU method with no consideration of that heat. Calculations are conducted for typical exchanger parameters and operating conditions. The results generated by these four methods are presented and compared. It is found that, although the effectiveness-NTU method is easy to use, it is incapable of yielding accurate results on moisture and enthalpy effectivenesses, while the numerical method can provide not only more accurate various effectivenesses but also the distributions of various physical parameters. Of the four performance evaluating methods, the numerical method with consideration of the adsorption heat can give the best results.