Refrigerant circulation device and control method

Abstract

A refrigerant circulation device includes a common flow path, first and second flow paths branching from the common flow path, a third flow path, a heat exchanger through which the first and third flow paths extend and in which heat is exchanged, a first valve to adjust the flow rate of the first flow path, a second valve to adjust the flow rate of the second flow path, a sensor to detect a temperature of a refrigerant, a device temperature that is a temperature in the device, and a relative humidity in the device, and a changing assembly to change first and second opening degrees of the first and second valve such that a sum of the first and second opening degrees becomes a predetermined value, based on the temperature, the device temperature, and the relative humidity.

What is claimed is: 
     
         1 . A refrigerant circulation device comprising:
 a common flow path through which a primary refrigerant flows;   a first flow path and a second flow path branching from the common flow path;   a third flow path through which a secondary refrigerant flows;   a heat exchanger through which the first flow path and the third flow path extend and in which heat is exchanged between the primary refrigerant and the secondary refrigerant;   a first valve to adjust a flow rate of the primary refrigerant in the first flow path;   a second valve to adjust a flow rate of the primary refrigerant in the second flow path;   a sensor to detect a secondary temperature that is a temperature of the secondary refrigerant, a device temperature that is a temperature in the device, and a relative humidity in the device; and   a changing assembly to change a first opening degree that is an opening degree of the first valve and a second opening degree that is an opening degree of the second valve such that a sum of the first opening degree and the second opening degree becomes a predetermined value, based on the secondary temperature, the device temperature, and the relative humidity.   
     
     
         2 . The refrigerant circulation device according to  claim 1 , wherein the changing assembly periodically determines a change width of the first opening degree and the second opening degree, based on the secondary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree with the change width. 
     
     
         3 . The refrigerant circulation device according to  claim 1 , further comprising:
 a setting assembly to set a target temperature of the secondary temperature; wherein   the changing assembly changes the first opening degree and the second opening degree such that the secondary temperature approaches the target temperature.   
     
     
         4 . The refrigerant circulation device according to  claim 3 , wherein the changing assembly changes the first opening degree and the second opening degree such that the secondary temperature does not become equal to or lower than a dew point during a time in which the target temperature is equal to or lower than the dew point based on the device temperature and the relative humidity. 
     
     
         5 . The refrigerant circulation device according to  claim 1 , wherein
 the sensor further detects a primary temperature that is a temperature of the primary refrigerant on an upstream side of the heat exchanger; and   the changing assembly determines a cycle to change the first opening degree and the second opening degree based on the primary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree with the cycle.   
     
     
         6 . The refrigerant circulation device according to  claim 3 , wherein
 the sensor detects the secondary temperature on a downstream side of the heat exchanger in the third flow path; and   the changing assembly determines a cycle to change the first opening degree and the second opening degree based on at least one of the secondary temperature, a combination of the device temperature and the relative humidity, and the target temperature, and then changes the first opening degree and the second opening degree with the cycle.   
     
     
         7 . The refrigerant circulation device according to  claim 1 , wherein
 the first valve is a two-way valve disposed in the first flow path;
 the second valve is a two-way valve disposed in the second flow path; and 
 flow rates of the first flow path and the second flow path are same. 
   
     
     
         8 . The refrigerant circulation device according to  claim 1 , wherein the changing assembly includes an electronic circuit, and is located above the common flow path, the first flow path, the second flow path, and the third flow path in a vertical direction of the refrigerant circulation device. 
     
     
         9 . The refrigerant circulation device according to  claim 3 , wherein
 when a difference between the secondary temperature and a dew point based on the device temperature and the relative humidity is equal to or larger than a reference value, the changing assembly determines a change width of the first opening degree and the second opening degree to be a first change width, and then increases the first opening degree by the first change width and decreases the second opening degree by the first change width so that a temperature of the secondary refrigerant approaches the target temperature; and   when the difference between the secondary temperature and the dew point is less than the reference value, the changing assembly determines a change width of the first opening degree and the second opening degree to be a second change width that is smaller than the first change width, and changes the first opening degree and the second opening degree by the second change width.   
     
     
         10 . The refrigerant circulation device according to  claim 1 , wherein the changing assembly changes the predetermined value based on the secondary temperature, the device temperature, and the relative humidity. 
     
     
         11 . The refrigerant circulation device according to  claim 1 , wherein the changing assembly lowers the predetermined value when the secondary temperature is equal to or lower than a dew point. 
     
     
         12 . A refrigerant circulation device comprising:
 a common flow path through which a primary refrigerant flows;   a first flow path and a second flow path branching from the common flow path;   a third flow path through which a secondary refrigerant flows;   a heat exchanger through which the first flow path and the third flow path extend and in which heat is exchanged between the primary refrigerant and the secondary refrigerant;   a first valve to adjust a first flow rate that is a flow rate of the primary refrigerant in the first flow path;   a second valve to adjust a second flow rate that is a flow rate of the primary refrigerant in the second flow path;   a sensor to detect a secondary temperature that is a temperature of the secondary refrigerant, a device temperature that is a temperature in the device, and a relative humidity in the device; and   a changing assembly to change a first opening degree that is an opening degree of the first valve and a second opening degree that is an opening degree of the second valve such that a sum of the first flow rate and the second flow rate becomes a predetermined value, based on the secondary temperature, the device temperature, and the relative humidity.   
     
     
         13 . A control method for a refrigerant circulation device, the refrigerant circulation device including:
 a common flow path through which a primary refrigerant flows;   a first flow path and a second flow path branching from the common flow path;   a third flow path through which a secondary refrigerant flows;   a heat exchanger through which the first flow path and the third flow path extend and in which heat is exchanged between the primary refrigerant and the secondary refrigerant;   a first valve to adjust a flow rate of the primary refrigerant in the first flow path; and   a second valve to adjust a flow rate of the primary refrigerant in the second flow path, the control method comprising:   detecting a secondary temperature that is a temperature of the secondary refrigerant, a device temperature that is a temperature in the device, and a relative humidity in the device; and   changing a first opening degree that is an opening degree of the first valve and a second opening degree that is an opening degree of the second valve such that a sum of the first opening degree and the second opening degree becomes a predetermined value, based on the secondary temperature, the device temperature, and the relative humidity.