Removal Effect of Bio-contaminants in a Packaged Liquid Desiccant-assisted Air Conditioning Unit

Abstract

The purpose of the study is to evaluate the removal effects of microbial contamination, such as fungi and bacteria, on a packaged liquid desiccant-assisted air conditioning unit. Recently, a package unit of a liquid desiccant and indirect and direct evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS) was proposed. The LDIDECOAS consists of a liquid desiccant system, an indirect evaporative cooler, and a direct evaporative cooler. The test was conducted under operating conditions during the cooling season when the LD-IDECOAS operates a liquid desiccant system, an indirect evaporative cooler, and a direct evaporative cooler. The sampling is performed ate the inlet (outdoor air) and outlet (supply air) of the package unit. Fungi were cultured in a potato dextrose agar (PDA) medium, and bacteria were cultured in a tryptic soy agar (TSA) medium as indices of bio-contaminants. The results indicated that the concentration of fungal contamination in the supply air (that passes through the package unit) decreased by 7.7% when compared to that of outdoor air. The concentration of bacterial contamination in the outlet was also reduced by 72.4% when compared to that in the inlet. Hence, the package unit improves air quality by removing bio-contaminants, such as fungi and bacteria, although unexpected contamination occurred in the experiment.