An analytical approach to multi-cylinder regenerative machines with application to 3-cylinder heat-aided Stirling heat pump

This paper describes a method for analysis and optimization of multi-cylinder regenerative machines. The authors have devised the method in a project at KUBOTA to develop an improved gas engine-driven heat pump using both shaft power and exhaust heat sources. Based on combinations of included Stirling cycles, this analytical approach allows use of well-established and validated Stirling simulation models to optimize partial systems. The technique further provides a method of integrating such optimal partial-system Stirling cycles into a complex combination system. It is shown that this remains an optimum solution for the three-cylinder fire assisted heat pump case. Results from hardware tests of the main Stirling heat pump cycle (2-cylinders) are given and compared with analytical expectations using the Sage simulation code. This is extended to validate Sage modelling of 3-cylinder machines