Energy saving potential of hybrid liquid desiccant and evaporative cooling air-conditioning system in Hong Kong

Abstract

The hybrid liquid desiccant dehumidification and evaporative cooling system, short for LDD-EC system, is regarded as a promising energy-saving air-conditioning (A/C) scheme for hot and humid regions. Unlike most previous reported LDD-EC system based on traditional indirect evaporative cooler (IEC) and 100% fresh air system, the LDD-EC system with partial circulation air was explored by fully making use of dry return air from air-conditioned space. The regenerative indirect evaporative cooler (RIEC) is used to sensibly cool the return air. The outdoor fresh air is firstly dehumidified in the LDD unit to have the latent heat removed, and then further cooled by RIEC. The LDD model, EC model and space model were established separately to facilitate the hybrid system simulation under the typical hot and humid condition in Hong Kong. The energy saving potential of the proposed system is quantitatively evaluated with respect to the conventional vapor compression A/C system. The results show an attractive energy saving ratio of 23.5% under Hong Kong weather condition. The energy saving ratio increases to 70% if the waste heat could be utilized.