Centrifugal chiller and centrifugal chiller operation method

Abstract

A centrifugal chiller includes a first expansion unit (23) that expands refrigerant that has been compressed and condensed, and an evaporation unit (41) that evaporates the expanded refrigerant and supplies the evaporated refrigerant to a compression unit (15). The first expansion unit (23) has an orifice (20) through which refrigerant condensed by a condensation unit (17) passes, and a flow rate regulation valve (22) that can regulate the amount of refrigerant condensed by the condensation unit (17) flowing through and that is connected in parallel with the orifice (20).

1 - 10 . (canceled) 
     
     
         11 . A centrifugal chiller comprising:
 a refrigeration cycle which includes a compression unit which compresses a refrigerant, a condensation unit which condenses the refrigerant compressed by the compression unit, an expansion unit which expands the refrigerant condensed by the condensation unit, and an evaporation unit which evaporates the refrigerant expanded by the expansion unit and supplies the expanded refrigerant to the compression unit, and through which the refrigerant circulates,   wherein the expansion unit includes
 an orifice through which the refrigerant condensed by the condensation unit passes, and 
 a flow regulation valve which is connected in parallel to the orifice and adjusts a passing amount of the refrigerant condensed by the condensation unit, and wherein 
 the centrifugal chiller further comprises a control device which is electrically connected to the flow regulation valve, 
   wherein the control device causes the refrigerant condensed by the condensation unit to pass through the orifice and the flow regulation valve when a load factor is equal to or more than a partial load peak at which a coefficient of performance during a partial load operation is maximized, and the control device fully closes the flow regulation valve and causes the refrigerant condensed by the condensation unit to pass through only the orifice when the load factor is less than the partial load peak.   
     
     
         12 . The centrifugal chiller according to  claim 11 , further comprising:
 an inlet temperature detection unit which is electrically connected to the control device and detects a cooling water inlet temperature which is a temperature of cooling water introduced into the condensation unit;   an outlet temperature detection unit which is electrically connected to the control device and detects a cooling water outlet temperature which is a temperature of the cooling water led out from an inside of the condensation unit;   a flow meter which measures a flow rate of the cooling water;   a first flow rate detector which is electrically connected to the control device and detects a first flow rate of the refrigerant flowing through the orifice, the refrigerant being a liquid; and   a second flow rate detector which is electrically connected to the control device and detects a second flow rate of the cooling water flowing through the flow regulation valve, the cooling water being a liquid,   wherein based on the cooling water inlet temperature, the cooling water outlet temperature, the flow rate of the cooling water, and the load factor during an operation, the control device regulates an opening degree of the flow regulation valve such that a sum of the first and second flow rates is a predetermined circulation flow rate.   
     
     
         13 . The centrifugal chiller according to  claim 11 ,
 wherein the flow regulation valve is an electric ball valve.   
     
     
         14 . The centrifugal chiller according to  claim 11 , further comprising:
 an economizer which is disposed between the condensation unit and the evaporation unit, reduces a pressure of a portion of a high-temperature and high-pressure refrigerant compressed by the compression unit to an intermediate pressure, and returns the refrigerant whose pressure is reduced to the intermediate pressure to the compression unit,   wherein the expansion unit is disposed between the condensation unit and the economizer and between the economizer and the evaporation unit.   
     
     
         15 . The centrifugal chiller according to  claim 14 , further comprising:
 a first line which connects an outlet of the condensation unit and an inlet of the economizer to each other; and   a second line which connects an outlet of the economizer and an inlet of the evaporation unit to each other,   wherein one of the orifice and the flow regulation valve is provided in each of the first and second lines, and   wherein a bypass line which bypasses the one is provided in each of the first and second lines and the other of the orifice and the flow regulation valve is provided in the bypass line.   
     
     
         16 . The centrifugal chiller according to  claim 11 ,
 wherein the refrigerant is a low-pressure refrigerant whose pressure in normal use is less than 0.2 MPa.   
     
     
         17 . An operation method of a centrifugal chiller including a refrigeration cycle which includes a compression unit which compresses a refrigerant, a condensation unit which condenses the refrigerant compressed by the compression unit, an expansion unit which expands the refrigerant condensed by the condensation unit, and an evaporation unit which evaporates the refrigerant expanded by the expansion unit and supplies the expanded refrigerant to the compression unit, and through which the refrigerant circulates, the expansion unit including an orifice through which the refrigerant condensed by the condensation unit passes, and a flow regulation valve which is connected in parallel to the orifice and adjusts a passing amount of the refrigerant condensed by the condensation unit,
 the operation method comprising:   allowing the refrigerant condensed by the condensation unit to pass through the orifice and the flow regulation valve when a load factor is equal to or more than a partial load peak at which a coefficient of performance during a partial load operation is maximized, and fully closing the flow regulation valve and allowing the refrigerant condensed by the condensation unit to pass through only the orifice when the load factor is less than the partial load peak.   
     
     
         18 . The operation method of a centrifugal chiller according to  claim 17 , further comprising:
 based on a cooling water inlet temperature which is a temperature of cooling water introduced into the condensation unit, a cooling water outlet temperature which is a temperature of the cooling water led out from an inside of the condensation unit, a flow rate of the cooling water, a first flow rate of the refrigerant flowing through the orifice, the refrigerant being a liquid, a second flow rate of the cooling water flowing through the flow regulation valve, the cooling water being a liquid, and the load factor during an operation, regulating an opening degree of the flow regulation valve such that a sum of the first and second flow rates is a predetermined circulation flow rate.   
     
     
         19 . The operation method of a centrifugal chiller according to  claim 17 ,
 wherein the refrigerant is a low-pressure refrigerant whose pressure in normal use is less than 0.2 MPa.