Performance Studies of R134a-Dimethylformamide Absorption Refrigeration System for Utilizing Bus Exhaust Gas Based on Aspen Plus Software

In this passage, a steady-state simulation model of air-cooled absorption refrigeration is developed and validated by Aspen Plus software, in which R134a-dimethylformamide (DMF) is used as working pair. The model is originally established under the given conditions, where the temperatures of condensation, evaporation, ambient surroundings, and waste gas in generator are 50, 5, 35, and 550 °C, separately, the mass concentration range of cycle is 0.09, and the refrigeration load is 30 kW. Then, the effects of operating parameters on system performance are investigated. The simulation results present that when the generator heat load is about 65 kW, the COP value is the highest at this time, reaching about 0.385, and the solution circulation ratio is 8.68. It is also found that under most load operating conditions, the value of COP is above 0.35, which proves that R134a-DMF working fluids have great potential for utilizing waste heat in bus.