Abstract: An automotive air conditioning system utilizes environmentally safe gases as the working fluid for a Stirling cycle refrigeration unit. The Stirling cycle refrigeration unit includes a compressor housing and an expander housing. A first heat transfer fluid circulation system removes heat from the compressor housing and expels it to the ambient atmosphere. A second heat transfer fluid circulation system removes heat from the automotive interior and expels it to the expander housing. Each of the compressor housing and the expander housing contains an equal number of cylinders. Respective cylinders in the compressor housing and the expander housing are fluidically connected to one another; and the reciprocal movement of pistons disposed in these respective cylinders is maintained in a specified phase relationship.