Testing of Materials for Heat and Moisture Transport

Abstract

The article deals with testing materials for using in enthalpy exchangers. The purpose of the enthalpy heat exchangers is to transport the heat and moisture together. Such heat exchangers are used in heat and ventilation air conditioning units. There are several methods how to test transport of moisture through material used in textile industry. However, these methods are not suitable for testing of materials, which are considered to be in heat exchangers. Methods for testing of moisture transport are usually based on free convection around membrane, which separates spaces with air of low humidity and air saturated with water. The free convection does not occur in heat exchangers and moisture varies in wide range. Therefore we developed and tested a devise to simulate moisture transport in enthalpy heat exchangers with plates, where co-current and countercurrent occur. With the help of this device, we could compare materials and evaluate the influence of the surface structure, which affect the boundary layers and heat and mass transport, when the flow is tangential to the material surface. We could also investigate the effect of flow velocity and humidity. The methods of evaluation are discussed and some results are presented.