Development of tri-generation system combining Stirling cooler and Stirling engine

This study is aimed at developing a tri-generation system that converts a thermal energy source to mechanical power, cooling. and heating simultaneously for the residential houses or factory buildings. The approach is implemented by combining a Stirling cooler and a Stirling engine. The input thermal energy is converted into mechanical power by the Stirling engine. A part of the mechanical power is utilized by an external load, and the remaining part of the mechanical power is used to drive the Stirling cooler to provide a cooling effect. In addition, the heats rejected by both the devices are used for water heating. In this study, a theoretical model including thermodynamic and dynamic analyses is developed to predict the performance of the combined system. For validation, a Stirling cooler and a Stirling engine are built and connected, and experiments are conducted to partially demonstrate the feasibility of the present approach. The results show that the experiments closely agree with the numerical predictions for the variations in the cold head temperature of the cooler and the stable rotation speed of the combined system. According to the energy flow analysis, the overall efficiency of the tri-generation system can reach approximately 91%.