Feasibility study of simultaneous heating and dehumidification using an adsorbent desiccant wheel with humidity swing

Abstract

Adsorptive desiccant dehumidification generates heat from adsorption, which can be used for space heating. Theoretically, a difference in relative humidity between the process air and the regeneration air is sufficient to produce the adsorption and desorption of water vapor onto and from the desiccant wheel. Taking advantage of this phenomenon, we proposed a desiccant wheel that used humidity swing adsorption (HSA), offering simultaneous heating and dehumidification.We first experimentally investigated the differences in the temperature and humidity of the adsorption air at the inlet and outlet of the desiccant wheel. We confirmed that the dehumidification and a rise in temperature occurred with only a difference in absolute humidity between the dehumidification and regeneration air. The theoretical maximum temperature rise assuming adiabatic dehumidification was estimated to be 15°C for adsorption and desorption inlet air of 25°C and 15g/kg-DA and 25°C and 3.6g/kg-DA. The experimentally measured temperature rise was decreased to 9.4°C mainly due to the heat capacity of the wheel used in the experiments. It was found that a regeneration temperature greater than 13°C was required to obtain a heating effect under our experimental conditions.