A new finned reciprocating air compressor model is developed recently for compressed air energy storage. First the mechanism of operation of the new compressor is described. The complexity of the design encouraged us to develop the model based on the bond graph representation of a model developed earlier by Karnopp (2000) for a classic compressor. The new finned compressor model is detached to thermal and pneumatic bonds. Compressing chambers in the new compressor were treated as interconnecting cylinder heads with heat transfer interaction with neighboring chambers through their common walls. The simulation was done and compared to a classic piston with the same characteristics followed by an experimental verification.