Modelling and experimental investigation of the cross-flow dew point evaporative cooler with and without dehumidification

This paper investigates the cooling potential of a cross-flow dew point evaporative cooler under various conditions. Preliminary study reveals that the dew point evaporative cooler's performance does not approach its designed capacity when the ambient humidity goes beyond the thermal comfort zone. To address this problem, an air dehumidification process is proposed before the evaporative cooling takes place. It is observed that the cross-flow cooler is able to achieve improved cooling effectiveness when an appropriate inlet air humidity condition is realized. The influence of different dehumidification levels on its cooling capacity and efficiency is subsequently analyzed. Additionally, a mathematical model is developed to predict the cooler performance. Key findings from this study are: (1) The maximum discrepancy between the simulation results and experimental data is within +/- 3.0%; (2) the overall wet bulb and dew point effectiveness of the cross-flow cooler can reach 1.25 and 0.85 for cooling of the supply air with moderate humidity; (3) the respective wet bulb effectiveness, cooling capacity and COP of the cross-flow system are 0.86, 2.2 kW and 4.6 under humid ambient air condition; and (4) the dehumidification of the supply air enables the cooling capacity and energy efficiency to be improved by 70-135%. (C) 2017 Elsevier Ltd. All rights reserved.