Energetic and exergetic performance investigation of a cross-flow regenerative indirect evaporative cooler made up of aluminium plate heat exchangers

Abstract

Evaporative cooling is an environmentally friendly and low-cost method to deliver cooling load in hot climates. It has been proposed as an alternative to traditional vapour compression systems, mainly due to its lower power consumption and the ability to provide cooling without the need for refrigerants. The present study investigates a novel regenerative indirect evaporative cooling system to address the high cooling demands in hot climates. The proposed unit consists of commercially available aluminium plate cross-flow heat exchangers. Within the study, system performance is simulated in MATLAB software and numerical results are validated with experimental testing results. In the analysis, the effects of exhaust-to-inlet air ratio, inlet air temperature and inlet air relative humidity on the system energetic and exergetic performance were investigated. Individual effects of the inlet parameters on the thermal, mechanical and chemical exergies of the inlet, product and exhaust air streams were also investigated. Maximum wet bulb effectiveness values were achieved as 0.99 and 1.06 for the single and double effect configurations, respectively. In all inlet air conditions, an optimal exhaust-to-inlet air ratio of 0.4 was found to maximize the cooling capacity. Maximum exergy destruction rate was 35W. On the other hand, yearly potential energy savings of 695 kWh was calculated by replacing a vapour compression system with the proposed regenerative evaporative cooler.