Latent heat cold storage integrated direct evaporative cooler: A neoteric practical design for energy and water saving potential with thermal comfort improvement

Abstract

In this study, a standalone cooling system has been proposed that combines both latent heat cold storage (LHCS) and direct evaporative cooler (DEC) in a unibody to work in harmony. The proposed configuration is an innovative compact practical cooling system that contributes to energy and water savings alongside the thermal comfort improvement by capturing and reusing the free cooling. Hereby, a detailed mathematical model has been developed and compared with four sets of experimental data from the published literature. The implemented LHCS is composed of a bundle of concentric tubes which are submerged inside the cold-water bath of the DEC to be solidified by the cold drain water. The PCMs are preserved inside the annulus of the concentric tubes. The captured free cooling from the LHCS is later utilized to lower the cooling load on the DEC by sensibly cooling a portion of the total air flow, which eventually contributes to saving in both energy and water consumption with further improvements in thermal comfort conditions. The findings demonstrated that the hybrid system can achieve about 24.84 % of energy saving and 14.89 % of water saving. Additionally, the thermal comfort of the conditioned space has been improved by up to 26.43 % and the hybrid system constantly produced a cold air with its relative humidity below 60 % which was one of the most prominent impediments of the DECs for achieving the thermal comfort condition.