Abstract: A refrigeration unit (10) includes a temperature control circuit (42) in which a plurality of coils (32) are wrapped around associated compressors (24, 26, 28, 30, 38 and 40) and are arranged in parallel between a supply manifold (44) and a return manifold (46) so that as long as one of the compressors is operating, heat will be transferred into a working fluid flowing through the coils in order to heat any non-operating ones of the compressors. Further, during warm weather, any excess heat can be dissipated from the working fluid to a suitable heat sink as by use of a heat exchanger or any appropriate heat reclaiming process. In extremely cold environments, heat can be added to the working fluid in a suitable manner to maintain the fluid above a predetermined minimum level necessary to assure proper functioning of the compressors.