Experimental Study on Variable Operating Characteristics of Two-Stage Absorption Lithium Bromide Refrigeration Chiller

Two-stage absorption lithium bromide (Li-Br) refrigeration technology can utilize low-temperature heat sources to achieve refrigeration, thus it holds promising application prospects in the utilization of low-temperature waste heat. However, the performance of two-stage lithium bromide absorption chillers during variable operating conditions is difficult to accurately predict, necessitating further research. Unlike existing simulation-based studies, this paper employs an experimental approach for the first time to investigate the variable-condition performance of a two-stage lithium bromide absorption chiller. A 10 kW two-stage absorption Li-Br chiller was tested under variable operating conditions, including variations in chilled water outlet temperature, cooling water inlet temperature, hot water inlet temperature, and hot water flow rate. The experimental results indicate that each 1 °C increase in the chilled water outlet temperature leads to an additional 0.282 kW in cooling capacity and a 0.0071 increase in coefficient of performance (COP). Similarly, a 1 °C decrease in the cooling water inlet temperature results in a 0.366 kW increase in cooling capacity and a 0.0055 improvement in COP. When the hot water inlet temperature rises by 1 °C, the cooling capacity increases by 0.324 kW, while the COP remains nearly unchanged. Furthermore, a 10% increase in the hot water mass flow rate enhances the cooling capacity by approximately 5% and improves the COP by about 1%.