The Thermal Performance of the Wet Surface Plastic Plate Heat Exchanger Used as an Indirect Evaporative Cooler

A mathematical model of the plate heat exchanger (PHE) cooling unit has been developed and solved using a digital computer. The equations of temperature distribution on each plate in a counterflow PHE cooling unit are derived using an energy balance analysis. The results are presented in the form of numerical values of the “overall effectiveness” of the heat exchanger. Factors affecting the effectiveness of the PHE cooling units have been investigated. The change of temperatures and humidity ratios of the air flows in the heat exchanger are also analyzed. Finally, the high performance of the PHE cooling unit is explained by introducing the concept of “enthalpy potential.” This unit is of particular interest as a component in solar-assisted cooling systems.