Extracting heat from very hot, dry rocks presents a more difficult problem: the rocks must be fractured to permit the circulation of water, and the water must be provided artificially.

Air circulation carries product heat and the heat which penetrates the walls, floors, and ceiling of the trailer to the refrigeration unit where it can be removed.

Reciprocating compressors can produce the work a lot of heat, so in working circulation cooling process between need to set.