The Characterization Of The Two Stage Absorption-compression Hybrid Refrigeration Cycle

The two stage absorption-compression hybrid refrigeration cycle, which is driven by the waste heat of the engine, can replace the traditional compression refrigeration, for it not only saves electrical energy consumed by the compressor and reduces the quantity of fuel while driving, but also a protection to the increasingly serious problem of environmental pollution. However, the amount of the exhaust heat is not stable, which means the air conditioning system can’t use absorption refrigeration solely but to apply the hybrid refrigeration cycle system. When the quantity of the exhaust heat is not enough, the absorption refrigeration system can’t provide sufficient refrigeration output and the compressor will provide the remaining amount of refrigeration. To utilize the exhaust heat to drive the air conditioner of the vehicle in complex road conditions, the two stage absorption-compression hybrid refrigeration cycle be put forward.By calculating the refrigeration load of the air conditioner in vehicles (which is30kw), we choose working fluid R124/DMAC, and under design condition (the air temperature35℃, the condensation55℃, the evaporation of the refrigerant3℃,the refrigeration load30kW) we can carry out the calculation of thermodynamic cycle and make it the theoretical basis to determine the structure of the device. Taking the road condition of Shanghai as research subject, we can determine the amount of exhaust heat under different speed (exhaust gas, cooling water) and make detailed analysis of the system characteristics by setting up the thermodynamic equilibrium equation of the engine.The result turns out that when the ambient temperature is around30to37℃, the system performs well, while the temperature is above37℃, the changing rate of the comprehensive performance coefficient decreases rapidly, which indicates that the ambient temperature exerts a prominent influence on the system. By researching the influence of the exhaust heat (the influence made by the high-temperature generator to the whole system when its load changes) we find out that as the load of the high-temperature generator becomes larger, the comprehensive performance coefficient of the system will become larger too, and the increasing tendency is becoming more and more quickly. Since the absorption-compression refrigeration system increases its refrigeration load, the power consumption of the compressor will surely decreases. In summary, the application of the two stage absorption-compression hybrid refrigeration cycle will have a bright future in city road conditions.