A refrigeration system for maintaining edible substances at a low temperature of the present invention includes a serving pan, an element for retaining or holding the serving pan, and a refrigeration tube and a glycol medium surrounding the pan is disclosed. The refrigeration tube and glycol medium act together in order to maintain the pan at a low temperature for a prolonged period of time and to provide an even cooling of the pan. In a second embodiment, the refrigeration tube may be surrounded by the glycol medium. In a further embodiment, the system may be used to heat food rather than to cool food by using a heat pump alone or in combination with electric heating elements.