Design of heat pump-driven liquid desiccant air conditioning systems for residential building

Abstract

In this study, two workable designs of a heat-pump-driven liquid desiccant (HPLD) air-conditioning system were proposed for residential buildings. The proposed HPLD systems were designed to work as a multi-functional air-conditioning system without additional equipment which would solve the low practicality due to the large scale and complexity of the conventional liquid-desiccant-assisted air-conditioning system. The critical difference between the two systems is the sump design for containing the desiccant solutions: Case A has a single sump instantly mixing weak and strong solutions, whereas Case B has dual sumps containing weak and strong solutions separately. The thermal load of target space was estimated using TRNSYS 18, and energy performances of both HPLD systems for summer and winter operation modes were analyzed using EES by integrating several established models and theoretical analyses. Owing to decrease in solution cooling and heating loads, the results show that Case B, compared with Case A, saved 28% of energy consumption and improved mean energy-efficiency by 37.5% for summer operation mode, and saved 12% of energy consumption and improved mean energy-efficiency by 4.95% for winter operation mode. In conclusion, Case B has a better application potential for residences in terms of energy performance.