Refrigeration system of the issue of "energy saving", meaning in terms of the parameters: such as chiller chilled water inlet, water temperature, cooling water, water temperature, indoor air temperature, temperature ... ... Under these conditions, each producing a cooling capacity of lkW energy consumption should be minimal, at the present energy saving" index: each production lkW cooling capacity of the power consumption shall not exceed 0.2I3kW, or every production of an American ton refrigeration quantity of power consumption shall not exceed 0.75kW, above the" energy consumption index" to control the air conditioning engineering design. However, air conditioning refrigeration system only considered in design condition of F, namely under the condition of full load operation energy consumption index is not enough, should also consider the refrigeration system under part load operation of the issue of "energy saving".