Auxiliary Heating, Cooling and Power Generation in Vehicles Based on Stirling Engine Technology

Regenerative cycles, the most well-known of which is the Stirling cycle, may be used for prime movers as well as for heat pump or refrigeration applications. Furthermore, it was demonstrated experimentally in a recent research project that it is possible to devise a machine that may be toggled between different cycles and operating modes in a demand-dependent way, and to achieve a satisfactory performance in any of these. The experimental machine realized within this project may be operated as a Stirling engine, as a thermally actuated Vuilleumier cycle heat pump or in a so-called hybrid mode featuring both a mechanical power production and a heat pump effect. The original objective was to develop a convertible domestic energy supply system that may be adjusted to varying heat and power demands, but particularly the hybrid cycle also appears to be well-suited for auxiliary heating cooling and power generation in vehicular applications, possibly even without the option of switching to different modes. The thermodynamic operating principle of this cycle, potential design options as well as performance predictions are presented and discussed.