Cooling performance and optimization of a tubular indirect evaporative cooler based on response surface methodology

Abstract

To optimize the cooling effectiveness of the tubular indirect evaporative cooler (TIEC), an experimental design was conducted using the response surface methodology (RSM). In this work, the wet-bulb effectiveness was selected as the response value, while the influencing factors included six operation parameters, namely, the spray water flow rate (Qw), secondary-to-primary air flow rate ratio (Rsp), primary air resistance (R1), secondary air resistance (R2), inlet air dry bulb temperature (tg1) and air relative humidity (RH). The operation conditions of a TIEC with a tube diameter of 10 mm were optimized. The second-order model fitting of the RSM was used to obtain the polynomial regression equation between the wet-bulb effectiveness and each factor. The wet-bulb effectiveness can be achieved up to 78 % under the optimized conditions with Qw of 1.2 m3/h, Rsp of 0.5, R1 of 89 Pa, R2 of 100 Pa, tg1 of 17.3 °C, and RH of 79.6 %.