Performance analysis of a novel dual-evaporation-temperature combined-effect absorption chiller for temperature and humidity independent control air-conditioning

Abstract

Temperature and humidity independent control (THIC) air-conditioning (AC) systems are promising alternatives to conventional AC systems. A novel dual-evaporation-temperature combined-effect (DETCE) absorption chiller for THIC AC application is proposed. It can produce high-temperature (16–18 °C) and low-temperature (7 °C) chilled water with a thermal coefficient of performance (COP) above 1 by the deep utilization of heat source at around 100–120 °C. Theoretical models were established to investigate effects of generation temperature (Tgen), evaporation temperature and high-temperature cooling capacity ratio (HCR) on thermal performance of the novel chiller. The results show that the COP of the proposed chiller (COPch,prop) is largely affected by Tgen and HCR. The COPch,prop is 24.1 %-50.4 % larger than that of the conventional single-effect absorption chiller (SEABC) under typical HCRs (0.5–0.7). Performance comparison of the DETCE absorption chiller-based THIC AC system and the conventional SEABC-based AC system was also conducted under different room sensible heat ratios (RSHR), fresh air ratios (FR) and ambient conditions. It is found that the proposed system has a greater energy-saving potential when applied in an air-conditioned space with a large RSHR and FR. Under typical RSHRs (0.6–0.8), both the thermal energy saving rate (ESR) and the heating fluid saving rate of the novel system are over 20 %. Besides, the proposed system can achieve an average ESR of around 30 % under a wide range of ambient conditions. This study provides a novel solution for the deep utilization of solar energy or waste heat at around 100–120 °C to achieve efficient and environmentally friendly THIC AC.