an energy - saving refrigeration system capable of reducing the quantity of energy and the cost required to operate refrigerators while contributing to greater efficiency in the operation of the utility facility that supplies the energy is provided by treating separately the functions of producing cold and using that cold to accomplish refrigeration . cold is produced in a compressor , condenser evaporator combination , and is stored in a cold storage unit from which it is removed , by heat input , at selected times . the times of cold production and of cold utilization are selected so that they accomplish a continued and adequate refrigeration function while transferring most energy usage from the highest cost peak load period of the energy source to another time . certain features , including a cold storage unit and shroud , enhance efficiency . the method of defrost and case condensation control additionally reduces energy required for evaporator frost and case moisture removal .