Energy performance analysis of a thermoelectric-module integrated liquid desiccant dehumidification on the evaporative cooling-assisted 100% air system

Abstract

The main purpose of this research is to investigate the impact of heat pump and thermoelectric module on a liquid desiccant and evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS). In conventional LD-IDECOAS operation, the boiler which provides regeneration heat to the weak desiccant solution consumes most of the overall energy consumption. In order to reduce the regeneration energy consumption in the LD-IDECOAS, a heat pump-integrated LD-IDECOAS (HPLD-IDECOAS) and thermoelectric module-integrated LD-IDECOAS (TEMLD-IDECOAS) are suggested in this research. The heat pump and thermoelectric module reclaim waste heat from the absorber side of the system, and deliver the reclaimed heat to the regenerator side. Detailed energy simulations for both systems were conducted to evaluate the energy saving potential of the proposed systems over the conventional LD-IDECOAS. In all the systems, it was assumed that a packed-bed type liquid desiccant unit with an aqueous solution of lithium chloride (LiCl) was used. The results show that only the HPLD-IDECOAS was able to provide 33% reduction in the annual primary energy consumption compared with the conventional LD-IDECOAS. This significantly enhanced energy performance was mainly obtained through an 85% reduction of the gas energy consumed for regeneration of the desiccant solution by applying the heat pump. However, TEMLD-IDECOAS was not able to show energy conservative potential despite the 100% reduction in the gas energy due to its current technological limits.