Analysis of working parameters for an ammonia-water absorption refrigeration system powered by automotive exhaust gas

摘要

In the present work, an experimental investigation was performed to determine effective working parameters for an ammonia-water absorption refrigeration system powered by waste heat from the exhaust gases of a vehicular internal combustion engine. The automotive exhaust system was connected to the generator of a commercial absorption refrigerator originally intended to operate with the heat generated from an LPG burner. In an attempt to increase performance, a close-looped exhaust gas flow control system was designed and implemented that allowed the generator temperature to be maintained at pre-determined values. Thus, a series of tests were performed with varying generator temperatures (180, 200, 240, and 270?°C) while monitoring engine torque, speed, and temperature at different points of the system. Using this methodology, it was found that the system is significantly sensitive to generator temperatures, and satisfactory performance was only noted for the set value of 200?°C. Under this operating condition, after 240?min test runs, minimum temperatures of ?12.5 and ?0.6?°C were obtained, respectively, at the evaporator element and interior of the absorption refrigerator, while the maximum coefficient of performance (COP) registered was almost 0.05.