Conceptual Design Of A Stirling Heat Pump/air Conditioning System

Stirling Thermal Motors, Inc., (STM) has developed a conceptual design for a Stirling cycle heat pump/ air conditioning system. This design is based on the 25 kW Stirling engine currently under development at STM which features a compact variable displacement, double-acting configuration and is designated the STM4-120 Stirling engine. Preliminary calculations have shown that a COP comparable with that of CFC vapor-compression systems is attainable. An even better COP can be expected based on the results of the computer simulation and optimization programs developed by N.V. Philips of the Netherlands during 30 years of research on Stirling engines and cryogenerstors. These programs were licensed to STM and developed further over the last decade. The STM variable displacement drive and power control has been proven to be rugged and reliable in engine applications. can be combined with high performance beat exchangers optimized with the Philips code for a proof -of -concept Stirling heat pump/air conditioning unit of 8 to 10-ton capacity. This Stirling configuration is amenable to scaling to achieve appropriate sizes for various applications. The unit can be shaft driven or combined with an electric motor integrated within the pressurized crankcase resulting in a hermetically sealed unit. The electrically driven configuration can be controlled with either a variable speed motor or by variable displacement of the Stirling unit. Details of the design, various configuration options and respective performance projections are presented and discussed.