Refrigerator and operating method of the same

Abstract

When a Stirling refrigerating engine for cooling a refrigerator starts, an operation is performed such that a gas-phase fluid flowing through a natural circulation circuit on a high temperature side attains a temperature higher than that in a normal operation. More specifically, the Stirling refrigerating engine operates with a piston drive speed higher than a normal speed, or a fan motor arranged for a condenser on the high temperature side stops. Thereby, a gas/liquid coexistent refrigerant in a high temperature side evaporator attains a pressure higher than a normal pressure. Thereby, a liquid phase fluid in a forced-circulation circuit on a high temperature side also attains a pressure higher than a normal pressure so that bubbles produced in the liquid phase fluid disappear, and a circulation pump can start.

1 . A refrigerator comprising:
 a cooling room for accommodating a target to be cooled;   a refrigerating machine having a cold head generating a cold air for cooling said cooling room and a warm head releasing heat caused by the generation of said cold air;   a liquid phase circulation circuit connected to said warm head and passing a liquid phase fluid;   a liquid phase circulation pump arranged in said liquid phase circulation circuit and circulating said liquid phase fluid; and   pressurizing means capable of pressurizing said liquid phase fluid.   
   
   
       2 . A refrigerator comprising:
 a cooling room for accommodating a target to be cooled;   a refrigerating machine having a cold head generating a cold air for cooling said cooling room and a warm head releasing heat caused by the generation of said cold air;   a liquid phase circulation circuit connected to said warm head and passing a liquid phase fluid;   a liquid phase circulation pump arranged in said liquid phase circulation circuit and circulating said liquid phase fluid;   a circulation circuit connecting said warm head to a condenser for liquidizing a gas phase fluid vaporized by the heat provided from said warm head; and   pressurizing means capable of pressurizing said liquid phase fluid.   
   
   
       3 . The refrigerator according to  claim 1  or  2 , wherein
 said pressurizing means is configured to perform the pressurizing by applying heat to said liquid phase fluid and/or said gas phase fluid from said warm head.   
   
   
       4 . The refrigerator according to  claim 1  or  2 , wherein
 said pressurizing means is heating means having a heat source independent of said warm head and being capable of applying heat to said gas phase fluid from said heat source.   
   
   
       5 . A method of operating a refrigerator including:
 a cooling room for accommodating a target to be cooled;   a refrigerating machine having a cold head generating a cold air for cooling said cooling room and a warm head releasing heat caused by the generation of said cold air;   a liquid phase circulation circuit connected to said warm head and passing a liquid phase fluid;   a liquid phase circulation pump arranged in said liquid phase circulation circuit and circulating said liquid phase fluid; and   a circulation circuit connecting said warm head to a condenser for liquidizing a gas phase fluid vaporized by the heat provided from said warm head, wherein   said liquid phase fluid is pressurized by applying a pressure higher than a pressure applied in a normal operation to said gas phase fluid after the start of the operation of said refrigerator until said liquid phase circulation pump appropriately circulates said liquid phase fluid.   
   
   
       6 . A refrigerator comprising:
 a cooling room for accommodating a target to be cooled;   a refrigerating machine having a cold head generating a cold air for cooling said cooling room and a warm head releasing heat caused by the generation of said cold air;   a liquid phase circulation circuit connected to said warm head and passing a liquid phase fluid;   a liquid phase circulation pump arranged in said liquid phase circulation circuit and circulating said liquid phase fluid;   a circulation circuit connecting said warm head to a condenser for liquidizing a gas phase fluid vaporized by the heat provided from said warm head; and   a control device controlling said refrigerating machine, wherein   said control device executes control of performing a high-speed operation of a piston of said refrigerating machine or control of increasing a stroke of a piston of said refrigerating machine such that said warm head of said refrigerating machine attains a temperature higher than that in a normal operation after the start of operation of said refrigerator until said liquid phase circulation pump appropriately circulates said liquid phase fluid.   
   
   
       7 . A refrigerator comprising:
 a cooling room for accommodating a target to be cooled;   a refrigerating machine having a cold head generating a cold air for cooling said cooling room and a warm head releasing heat caused by the generation of said cold air;   a liquid phase circulation circuit connected to said warm head and passing a liquid phase fluid;   a liquid phase circulation pump arranged in said liquid phase circulation circuit ( 60 ) and circulating said liquid phase fluid; and   a control device controlling said refrigerating machine and said liquid phase circulation circuit, wherein   said control device starts an operation of said liquid phase circulation pump or increases the output of said liquid phase circulation pump on condition that a predetermined time has elapsed after said refrigerating machine started an operation.   
   
   
       8 . A refrigerator comprising:
 a cooling room for accommodating a target to be cooled;   a refrigerating machine having a cold head generating a cold air for cooling said cooling room and a warm head releasing heat caused by the generation of said cold air;   a dew formation preventing pipe arranged along an inner surface of a casing, connected to said warm head and passing a liquid phase fluid;   a liquid phase circulation pump arranged in said liquid phase circulation circuit including said dew formation preventing pipe, and circulating said liquid phase fluid;   a control device controlling said refrigerating machine and said liquid phase circulation pump; and   a temperature sensor measuring a temperature of the surface of said casing or a temperature of said liquid phase circulation pipe, wherein   said control device starts an operation of said liquid phase circulation pump or increases the output of said liquid phase circulation pump on condition that the temperature sensed by said temperature sensor lowered.   
   
   
       9 . A refrigerator comprising:
 a cooling room for accommodating a target to be cooled;   a refrigerating machine having a cold head generating a cold air for cooling said cooling room and a warm head releasing heat caused by the generation of said cold air;   a liquid phase circulation circuit connected to said warm head and passing a liquid phase fluid;   a liquid phase circulation pump arranged in said liquid phase circulation circuit and circulating said liquid phase fluid;   a radiator for lowering a temperature of said warm head;   a radiator fan arranged near said radiator; and   a control device controlling said refrigerating machine, said liquid phase circulation pump and said radiator fan, wherein   before said liquid phase circulation pump starts after starting said refrigerating machine, said control device stops said radiator fan or drives said radiator fan with a power smaller than that used after starting said liquid phase circulation pump.