A practical application of the Joule air cycle to vehicle air conditioning

The motor car industry has been especially affected by the legislative constraints imposed on the release of man-created refrigerants because car air conditioning servicing costs are increased and greater system integrity is required, One solution may be to use air as the primary refrigerant. The author describes a practical way of adapting the Joule cycle for use in motor car air conditioning systems to match the typical performance of existing vapour compression systems, Low cost and easy physical integration with engine and bodywork have been primary targets. The proposed system comprises a powered turbo-bootstrap, a regenerative intercooler and a load heat exchanger, all readily incorporated in the engine compartment, Engine antifreeze coolant is used as a secondary refrigerant which is circulated between the load heat exchanger and a passenger compartment heat exchanger, doubling as a heater. an engine-driven generator provides alternating current to the powered bootstrap motor, and also satisfies the needs of the 12 volt battery system, All the components described are based on available technology. Inherently, the power requirement during initial compartment cool-down exceeds that of vapour compression systems, but whole-life energy consumption may be comparable because of efficient control and good off-design performance.