Performance Analysis of a Combined Absorption Refrigeration-Liquid Desiccant Dehumidification THIC System Driven by Low-Grade Heat Source

Abstract

Traditional condensing air-conditioning systems consume large amounts of energy in hot and humid areas, and it is difficult to achieve simultaneous control of temperature and humidity. A combined absorption refrigeration (AR) and liquid desiccant dehumidification (LDD) air-conditioning system based on cascade utilization of low-grade heat source is proposed. The system can realize independent control of temperature and humidity and carry out profound recovery of low-grade heat sources. Under the design conditions, the heat utilization rate ζ reaches 21.05%, which is 2.73 times that of the conventional absorption refrigeration reference system. A parametric sensitivity analysis is performed to optimize the system. The ζ increases from 9.79% to 18.55% and the coefficient of performance COPt increases from 0.33 to 0.35 with an increase in chilled water temperature from 7°C to 15°C. With an increase in regenerant solution temperature from 60°C to 70°C, the ζ achieves the optimal value of 21.05% at 68°C. ζ decreases from 21.05% to 15.05% as the concentration of the regenerant solution increases from 36% to 40%. Under variable environmental temperature and humidity, the ζ of the proposed system changes within a small range and stays much higher than that of the reference system with the same quality heat source, which indicates that the proposed system has a better adaptability to changing environmental parameters.