Patent ID: 7631510
Filing Date: 2009-12-15
Classification: F25B,F25D

Abstract:
1. A refrigerating apparatus comprising compression element having an intermediate and low pressure parts, radiator, auxiliary expansion means, intermediate heat exchanger, main expansion means and evaporator which constitute a refrigeration cycle, wherein refrigerant flowing out of said radiator is branched into two streams, in which (1) a first refrigerant stream passes through the first flow path of the intermediate heat exchanger via said auxiliary expansion means, (2) a second refrigerant stream passes through the second flow path of the intermediate heat exchanger, the main expansion means, the evaporator, and the low pressure part of the compression element, and merges with the first refrigerant stream, and (3) the merged stream flows into the intermediate pressure part of the compression element, heat exchange is performed between the two refrigerant stream within said intermediate heat exchanger, the refrigerant flowing out of said evaporator is sucked by the low pressure part of said compression element, the refrigerant flowing out of said intermediate heat exchanger is sucked by the intermediate pressure part of said compression element, wherein the temperature of said second refrigerant stream exiting the intermediate heat exchanger or the temperature of said first refrigerant stream exiting the intermediate heat exchanger is controlled to a predetermined value by adjusting the amount of said first refrigerant stream by controlling said auxiliary expansion means, the pressure in said intermediate pressure part of the compression element to an optimum intermediate pressure is controlled by adjusting the amount of said first refrigerant stream by controlling said auxiliary expansion means using an expression Pint,opt=Kint,opt*GMP=Kint,opt*(Psuc*Pdis) 0,5 , wherein Pint,opt: Optimum intermediate pressure Kint,opt: Optimum intermediate pressure coefficient GMP: Geometric mean of the pressure of the high pressure side and the pressure of the low pressure side Psuc: Pressure of the suction side of the compression element; and Pdis: Pressure of the discharge side of the compression element, and said Optimum intermediate pressure coefficient Kint,opt is set in the range of 1.1 to 1.6.