Cooling system and cooling method

Abstract

Cooling system and cooling method that enable preventing breakdown of coolant pump is provided. The cooling system, includes: evaporator for evaporating coolant by heat exchange with indoor air as an object of air conditioning; condenser for cooling and condensing coolant evaporated by evaporator; coolant liquid storage section that communicates with condenser and stores coolant liquid flowing in from condenser; coolant pump that communicates with coolant liquid storage section and pressure-transmits coolant liquid toward evaporator, the coolant liquid flowing in from coolant liquid storage section; coolant liquid detection units for individually detecting whether or not liquid level of coolant liquid stored in coolant liquid storage section is higher than or equal to respective plural heights including first height and second height higher than first height in coolant liquid storage section; and control unit that changes motor rotation speed of coolant pump, corresponding to detection result input from coolant liquid detection units.

What is claimed is: 
     
         1 . A cooling system, comprising:
 an evaporator for evaporating a coolant by heat exchange with indoor air that is an object of air conditioning;   a condenser for cooling and thereby condensing the coolant evaporated by the evaporator;   a coolant liquid storage section that communicates with the condenser and stores the coolant liquid flowing in from the condenser;   a coolant pump that communicates with the coolant liquid storage section and pressure-transmits the coolant liquid toward the evaporator, the coolant liquid flowing in from the coolant liquid storage section;   a coolant liquid detection unit for individually detecting whether or not a liquid level of the coolant liquid stored in the coolant liquid storage section is higher than or equal to respective plural heights including a first height and a second height higher than the first height in the coolant liquid storage section; and   a control unit that changes a rotation speed of a motor of the coolant pump, corresponding to a detection result that is input from the coolant liquid detection unit.   
     
     
         2 . The cooling system according to  claim 1 ,
 wherein the coolant liquid detection unit comprises plural liquid level sensors including a first liquid level sensor that detects whether or not coolant liquid with a liquid level higher than or equal to the first height is stored in the coolant liquid storage section and a second liquid level sensor that detects whether or not coolant liquid with a liquid level higher than or equal to the second height is stored in the coolant liquid storage section,   and wherein the control unit:   stops rotation of the motor when coolant liquid is not detected by the first liquid level sensor; and   resumes rotation of the motor when coolant liquid is detected by the second liquid level sensor.   
     
     
         3 . The cooling system according to  claim 1 ,
 wherein the coolant liquid detection unit comprises a pressure difference sensor arranged at the coolant liquid storage section,   and wherein the control unit:   stops rotation of the motor when a detection value by the pressure difference sensor has become lower than or equal to a first pressure that is a pressure at a time when coolant liquid is stored up to the first height; and   thereafter resumes rotation of the motor when a detection value by the pressure difference sensor has become higher than or equal to a second pressure that is a pressure at a time when coolant liquid is stored up to the second height.   
     
     
         4 . The cooling system of  claim 1 ,
 wherein a pipe connecting the coolant pump and the evaporator includes a standing tube that is standing up to a height higher than or equal to the second height.   
     
     
         5 . A cooling method for a cooling system,
 wherein the cooling system includes:   an evaporator for evaporating a coolant by heat exchange with indoor air that is an object of air conditioning;   a condenser for cooling and thereby condensing the coolant evaporated by the evaporator;   a coolant liquid storage section that communicates with the condenser and stores the liquid flowing in from the condenser;   a coolant pump that communicates with the coolant liquid storage section and pressure-transmits the coolant liquid toward the evaporator, the coolant liquid flowing in from the coolant liquid storage section;   a coolant liquid detection unit for detecting whether or not a liquid level of the coolant liquid stored in the coolant liquid storage section is higher than or equal to a predetermined height; and   a control unit,   the cooling method comprising the steps of:   individually detecting whether or not the liquid level of the coolant liquid stored in the coolant liquid storage section is higher than or equal to respective plural heights including a first height and a second height higher than the first height in the coolant liquid storage section; and   changing, by the control unit, a rotation speed of a motor of the coolant pump, corresponding to a detection result that is input from the coolant liquid detection unit.