Performance Study Of Duplex Stirling Refrigeration And Its Coupling With Absorption Refrigeration

Due to the building energy consumption is huge in our country.More and more attention has been paid to the heat driven refrigeration system with solar energy,waste heat and natural gas combustion heat as the driving heat source.Among them,the heat driven Stirling refrigeration system mainly uses the heat energy of medium and high temperature,and the heat driven absorption refrigeration system mainly uses the heat energy of medium and low temperature.Therefore,it is necessary to study the performance of the heat driven Stirling refrigeration system,heat driven absorption refrigeration system and their coupling systems.Firstly,according to the structure and working principle of the duplex Stirling cooler,the working process and advantages of the dwell-based motion duplex Stirling cooler are analyzed.The adiabatic mathematical model of the dwell-based motion duplex Stirling cooler is established,and the heat loss mechanism is introduced,including the heat loss of the regenerator,shuttle heat loss and heat conduction loss.The influence of compression ratio on system performance is analyzed.In order to meet the constraint of equal work between Stirling engine and Stirling cooler under variable conditions,two methods by reducing the temperature of hot chamber and increasing the dead volume of Stirling engine are adopted to adjust the output work of Stirling engine.Compared with the experimental results of relative Carnot efficiency,the rationality of dwell-based motion duplex Stirling cooler is proved.When the temperature of cold chamber is 5℃and the temperature of cooler’s warm chamber is35 ℃ ～50 ℃,the comprehensive coefficient of performance COP of the dwell-based motion duplex Stirling cooler is 1.02～1.397.However the COP could be decreased by up to 4.41% at the off-design conditions due to decreasing the hot chamber’temperature or increasing the dead volume of the Stirling engine.In addition,the overall performance of COP can be improved by 7.12% by increasing the dead volume compared with reducing the hot chamber’ temperature.Secondly,according to reasonable assumptions,the steady-state model of single/double effect lithium bromide absorption refrigeration system is established.The mathematical model of absorption refrigeration system is solved and verified by MATLAB.The influence of external operating parameters such as inlet temperature and flow of heat source water,inlet temperature and flow of cooling water,outlet temperature and flow of chilled water on system performance is analyzed.Finally,through the comparison between the dwell-based motion duplex Stirling cooler and absorption refrigerator,it is found that the performance COP of the dwell-based motion duplex Stirling cooler is higher than single effect absorption refrigerator,but the relative Carnot efficiency is lower than single effect absorption refrigerator.In order to give full play to their advantages,a coupling system of the dwell-based motion duplex Stirling cooler and absorption refrigerator is proposed.The single effect absorption refrigerator is driven by the waste heat of the engine’s warm chamber.Under the coupling condition,the COP of the coupled refrigeration system is 17.88% higher than that of the dwell-based motion duplex Stirling cooler.In this paper the performance of the dwell-based motion duplex Stirling cooler and its coupling with absorption refrigeration system was studied,which is of great significance to improve the performance of the heat driven refrigeration system and improve the energy efficiency.