Experimental and numerical analysis of desiccant wheels activated at low temperatures

Abstract

Desiccant wheels, DW, can be used to control the indoor air conditions in buildings and industrials environments. The control of the outlet process air conditions of a DW can be obtained by controlling the moisture removal capacity, MRC, and sensible heat ratio, SHR. The objective of this work is to obtain MRC and SHR of a DW activated at low temperatures when the process airflow rate and air regeneration temperature are varied. Two secondary objectives are to obtain the influence of the variation of the process airflow rate and air regeneration temperature on the outlet process air conditions and the relationship between MRC and SHR. Three empirical and simulated case studies are carried out.

The results show that a decoupling of the outlet air temperature and humidity ratio can be obtained when the process airflow rate and air regeneration temperature are varied. This decoupling allows several MRC values for a constant SHR value, and vice versa, to be obtained, achieving ranges of 7 kg h−1 and 0.25, respectively. These results suggest that a control strategy for DW activated at low temperatures, would allow MRC and SHR to be controlled by setting the process airflow rate and air regeneration temperature.