Entropy generation minimisation analysis of cross-flow heat exchangers used in indirect evaporative air conditioners

In this paper, entropy generation in heat exchangers used in Indirect Evaporative Coolers (IDECs) is studied. First, expressions for the rate of entropy generation in tube-type and plate-type cross-flow heat exchangers used as IDECs are obtained. Then, by introducing appropriate geometric constraints and employing thermohydraulic design equations, the variation of the rate of entropy generation within the heat exchangers is investigated. The maximum EER, outlet temperatures and the optimum sizes are obtained for several cases. The results of several experiments conducted on an optimum tube-type experimental prototype are presented and compared with the numerical data.

Keywords: entropy generation minimisation, second law analysis, exergy analysis, evaporative air coolers, evaporative air conditioners, tube-type heat exchangers, plate-type heat exchangers, experimental prototypes, cross-flow heat exchangers, indirect evaporative coolers, thermohydraulic design