Experimental study on total heat transfer efficiency evaluation of an indirect evaporative cooler

摘要

Indirect evaporative cooler is applied as a device of the combined air conditioning system to precool the fresh air in hot and humid regions, which may cause condensation in the primary air channels. For this case, the trend of the existing evaluation indexes used to express the heat exchange efficiency is inconsistent with that of the total heat transfer. In this paper, a plate cross-flow indirect evaporative cooling experimental system was set up, and the inadaptability of the existing evaluation indexes was analyzed by applying the experimental data. A new index called enthalpy efficiency was introduced in this paper. It was found that the change curve of enthalpy efficiency was highly consistent with that of the total heat transfer. By utilizing the data in other literatures, it was proved that the enthalpy efficiency can be used to evaluate the heat transfer capacity of plate cross-flow and counter-flow indirect evaporative coolers. The evaluation index can be used for thermal calculation, equipment selection design and performance optimization of an indirect evaporative cooler.