Experimental and simulation study on an air conditioning system cascade driven by waste heat using multicomponent solution

Abstract

The cascade utilization of waste heat for air conditioning system is still considerably lacking in the literature, especially for waste heat below 80.0 °C. In this paper, the experimental and simulation studies are carried out on an air conditioning system that integrates the absorption refrigeration subsystem (ARS) with the liquid desiccant dehumidification subsystem (LDDS). The waste heat at 80 °C is first used to drive the ARS to produce chilled water for air cooling, and then drive the LDDS for air dehumidification to realize heat cascade utilization. Firstly, the experimental study is conducted to compare CaBr2–LiCl–H2O with LiBr–H2O in the ARS and CaBr2–CaCl2–H2O with LiCl–H2O in the LDDS. The results show that the multicomponent solutions perform comparably to the single-component solutions. Then, a mathematical model is established to simulate the entire system using the appropriate multicomponent solution for each subsystem. It is found that the COP of the system reaches 0.77 at a driving temperature of 80.0 °C, with the supply air temperature of 23.0 °C and the humidity ratio of 10.5 g/kg. The waste heat can be recovered down to 61.0 °C, achieving a heat recovery depth of 19.0 °C. This system is expected to have significant potential in the applications due to its efficient heat utilization capability and low-cost multicomponent solutions.