US20200232682A1 - Centrifugal chiller and centrifugal chiller operation method - Google Patents

Centrifugal chiller and centrifugal chiller operation method Download PDF

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Publication number
US20200232682A1
US20200232682A1 US16/486,454 US201816486454A US2020232682A1 US 20200232682 A1 US20200232682 A1 US 20200232682A1 US 201816486454 A US201816486454 A US 201816486454A US 2020232682 A1 US2020232682 A1 US 2020232682A1
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Prior art keywords
refrigerant
unit
cooling water
regulation valve
orifice
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US16/486,454
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English (en)
Inventor
Naoya Miyoshi
Kenji Ueda
Kazuki Wajima
Yasushi Hasegawa
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Mitsubishi Heavy Industries Thermal Systems Ltd
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Mitsubishi Heavy Industries Thermal Systems Ltd
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Assigned to MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD. reassignment MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HASEGAWA, YASUSHI, MIYOSHI, NAOYA, UEDA, KENJI, WAJIMA, KAZUKI
Publication of US20200232682A1 publication Critical patent/US20200232682A1/en
Abandoned legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/022—Compressor control arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2339/00—Details of evaporators; Details of condensers
    • F25B2339/04—Details of condensers
    • F25B2339/047—Water-cooled condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/13—Economisers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/23—Separators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2515—Flow valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/13—Mass flow of refrigerants
    • F25B2700/133—Mass flow of refrigerants through the condenser
    • F25B2700/1332—Mass flow of refrigerants through the condenser at the outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/13—Mass flow of refrigerants
    • F25B2700/135—Mass flow of refrigerants through the evaporator
    • F25B2700/1352—Mass flow of refrigerants through the evaporator at the inlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2116—Temperatures of a condenser
    • F25B2700/21161—Temperatures of a condenser of the fluid heated by the condenser
    • F25B41/04—

Definitions

  • the present invention relates to a centrifugal chiller and a centrifugal chiller operation method.
  • a centrifugal chiller has a refrigeration cycle which includes a compressor (compression unit), a condenser (condensation unit), an evaporator (evaporation unit), and a pressure reduction mechanism (expansion unit) (refer to PTL 1).
  • a high-pressure gas refrigerant compressed according to a capacity control operation of the compressor is supplied to the condenser to be condensed and liquefied. Thereafter, a liquid refrigerant is expanded under reduced pressure using the pressure reduction mechanism (expansion unit) and is supplied to the evaporator, and the liquid refrigerant is evaporated by the evaporator and is returned to the compressor.
  • PTL 1 discloses that an orifice is used as a pressure reduction mechanism (expansion unit).
  • turbo compressor uses a pressure reduction mechanism (expansion unit) corresponding to the partial load operation, it is preferable to prevent a size of the centrifugal chiller from increasing.
  • an object of the present invention is to provide a centrifugal chiller and a centrifugal chiller operation method capable of suppressing a decrease in performance during a partial load operation while suppressing an increase in size.
  • 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, in which 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.
  • the expansion unit includes the 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. Therefore, 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, the refrigerant condensed by the condensation unit can pass through the orifice and the flow regulation valve, and when the load factor is less than the partial load peak, the flow regulation valve is fully closed, the refrigerant condensed by the condensation unit can pass through only the orifice. Accordingly, it is possible to suppress a decrease in performance during the partial load operation.
  • the orifice and the flow regulation valve are used together, and thus, it is possible to decrease a diameter of the flow regulation valve. Therefore, it is possible to decrease a size of the expansion unit, and thus, it is possible to suppress an increase in size of the centrifugal chiller.
  • the centrifugal chiller may further include a control device which is electrically connected to the flow regulation valve, the control device may cause the refrigerant condensed by the condensation unit to pass through the orifice and the flow regulation valve when the 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 may fully close the flow regulation valve and may cause the refrigerant condensed by the condensation unit to pass through only the orifice when the load factor is less than the partial load peak.
  • a control device which is electrically connected to the flow regulation valve
  • the control device may cause the refrigerant condensed by the condensation unit to pass through the orifice and the flow regulation valve when the 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
  • the control device may fully close the flow regulation valve and may cause the refrigerant condensed by the condensation unit to pass through only the orifice when the load factor is less than the partial
  • the control device configured as described above makes it possible to suppress the decrease in performance during the partial load operation while suppressing the increase in size of the centrifugal chiller.
  • the centrifugal chiller may further include 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, in which 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 may regulate
  • control device which regulates the opening degree of the flow regulation valve such that the sum of the first and second flow rate is the predetermined circulation flow rate, 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, makes it possible to suppress the decrease in the performance during the partial load operation.
  • the flow regulation valve may be an electric ball valve.
  • the electric ball valve is used as the flow regulation valve, and thus, it is possible to decrease a diameter of the electric ball valve. Accordingly, it is possible to suppress the increase in size of the flow regulation valve.
  • the centrifugal chiller may further include 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, in which the expansion unit may be disposed between the condensation unit and the economizer and between the economizer and the evaporation unit.
  • the economizer configured as described above makes it possible to extract a large refrigeration capacity even with small power.
  • the centrifugal chiller may further include 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, in which one of the orifice and the flow regulation valve may be provided in each of the first and second lines, and a bypass line which bypasses the one may be provided in each of the first and second lines and the other of the orifice and the flow regulation valve may be provided in the bypass line.
  • the refrigerant can flow to both the orifice and the flow regulation valve or the refrigerant can flow to only the orifice.
  • the refrigerant may be a low-pressure refrigerant whose pressure in normal use is less than 0.2 MPa.
  • the low-pressure refrigerant has a large specific volume as compared to a high-pressure refrigerant which is a subject to a regulation of a high pressure gas. Therefore, for example, if the orifice is not provided and only the flow regulation valve is provided in the centrifugal chiller, the size of the flow regulation valve increases.
  • the orifice and the flow regulation valve are used together, and thus, it is possible to suppress an increase in size of the flow regulation valve.
  • 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 including: 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
  • the refrigerant condensed by the condensation unit passes through the orifice and the flow regulation valve, and when the load factor is less than the partial load peak, the flow regulation valve is fully closed, the refrigerant condensed by the condensation unit passes through only the orifice. Accordingly, it is possible to suppress a decrease in performance during the partial load operation while suppressing an increase in size of the centrifugal chiller.
  • the operation method may further include 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.
  • the refrigerant may be a low-pressure refrigerant whose pressure in normal use is less than 0.2 MPa.
  • the low-pressure refrigerant has a large specific volume as compared to the high-pressure refrigerant which is a subject to a regulation of the high pressure gas. Therefore, for example, if the orifice is not provided and only the flow regulation valve is provided in the centrifugal chiller, the size of the flow regulation valve increases.
  • the orifice and the flow regulation valve are used together, and thus, it is possible to suppress an increase in size of the flow regulation valve.
  • FIG. 1 is a schematic diagram showing a schematic configuration of a centrifugal chiller according to an embodiment of the present invention.
  • FIG. 2 is a graph showing a relationship between a load factor (%) of the centrifugal chiller, a coefficient of performance (COP), and a temperature of a cooling water.
  • FIG. 3 is a functional block diagram of a control device of FIG. 1 .
  • FIG. 4 is a graph showing a relationship between a flow rate of a refrigerant passing through an orifice each cooling inlet temperature, a flow rate of the refrigerant passing through a flow regulation valve at each cooling inlet temperature, the load factor of the centrifugal chiller, and a temperature of an opening degree of the flow regulation valve.
  • a centrifugal chiller 10 of the present embodiment will be described with reference to FIG. 1 .
  • FIG. 1 as an example, a case where cooling water generated by an evaporation unit 41 is used in an external load 6 will be described as an example.
  • FIG. 1 for convenience of explanation, the external load 6 which is not a component of the centrifugal chiller 10 is shown.
  • the centrifugal chiller 10 has a refrigeration cycle 9 , a cooling tower 11 , a cooling water circulation line 12 , a chilled water circulation line 13 , and a control device 14 .
  • the refrigeration cycle 9 has a compression unit 15 , lines 16 , 32 , and 43 , a condensation unit 17 , an inlet temperature detection unit 18 A, an outlet temperature detection unit 18 B, a flow meter 18 C, a first line 19 , bypass lines 21 and 36 , a first expansion unit 23 , first flow rate detectors 26 and 39 , second flow rate detectors 29 and 40 , an economizer 31 , a second line 34 , a second expansion unit 38 , and an evaporation unit 41 .
  • the compression unit 15 is a centrifugal two-stage compressor and is electrically connected to the control device 14 .
  • the compression unit 15 has a rotary shaft (not shown), a low stage-side compression unit 51 , a high stage-side compression unit 52 , a motor 53 , inlets 15 A and 15 B, and an outlet 15 C.
  • the rotary shaft is configured to be rotatable by the motor 53 .
  • the low stage-side compression unit 51 and the high stage-side compression unit 52 are provided in the rotary shaft.
  • An inlet side of the low stage-side compression unit is connected to the other end of the line 43 via the inlet 15 A.
  • a refrigerant gas led out from the evaporation unit 41 is introduced into the inlet side of the low stage-side compression unit 51 via the line 43 .
  • An outlet side of the low stage-side compression unit 51 is connected to an inlet side of the high stage-side compression unit 52 .
  • the refrigerant gas compressed by the low stage-side compression unit 51 is supplied to the inlet side of the high stage-side compression unit 52 .
  • a portion between the outlet side of the low stage-side compression unit 51 and the inlet side of the high stage-side compression unit 52 is connected to the other end of the line 32 via the inlet 15 B. Accordingly, an intermediate-pressure refrigerant gas generated by the economizer 31 is injected to the portion between the low stage-side compression unit 51 and the high stage-side compression unit 52 via the line 32 .
  • An outlet side of the high stage-side compression unit 52 is connected to one end of the line 16 .
  • the compression unit 15 configured as described above compresses the refrigerant gas in a two-step compression manner to generate a high-temperature and high-pressure gas refrigerant, and leads the high-temperature and high-pressure gas refrigerant to the line 16 .
  • the other end of the line 16 is connected to an inlet 17 A of the condensation unit 17 .
  • the high-temperature and high-pressure gas refrigerant generated by the compression unit 15 is supplied to the condensation unit 17 through the line 16 .
  • the condensation unit 17 has the inlet 17 A and an outlet 17 B.
  • the high-temperature and high-pressure gas refrigerant is introduced into the inlet 17 A via the line 16 .
  • the outlet 17 B is connected to one end of the first line 19 .
  • a portion of the cooling water circulation line 12 through which cooling water cooled by the cooling tower 11 circulates is disposed in the condensation unit 17 .
  • condensation unit 17 configured as described above, heat exchange is performed between the high-temperature and high-pressure gas refrigerant and the cooling water, the gas refrigerant is condensed, and thus, a liquid refrigerant is generated.
  • the generated liquid refrigerant is led to the first line 19 .
  • a condenser can be used as the condensation unit 17 .
  • the inlet temperature detection unit 18 A is provided in the cooling water circulation line 12 through which the cooling water circulates between the cooling tower 11 and the condensation unit 17 .
  • the inlet temperature detection unit 18 A is disposed at a position at which the inlet temperature detection unit 18 A can detect a temperature (hereinafter, referred to as a “cooling water inlet temperature”) of the cooling water which is cooled by the cooling tower 11 and is introduced into the condensation unit 17 .
  • the inlet temperature detection unit 18 A is electrically connected to the control device 14 .
  • a temperature detection unit 18 transmits information on the detected cooling water inlet temperature to the control device 14 .
  • the outlet temperature detection unit 18 B is provided in the cooling water circulation line 12 .
  • the outlet temperature detection unit 18 B is disposed at a position at which the outlet temperature detection unit 18 B can detect a temperature (hereinafter, referred to a “cooling water outlet temperature”) of the cooling water led from the condensation unit 17 .
  • the outlet temperature detection unit 18 B is electrically connected to the control device 14 .
  • the outlet temperature detection unit 18 B transmits information on the detected cooling water outlet temperature to the control device 14 .
  • the flow meter 18 C is provided in the cooling water circulation line 12 .
  • the flow meter 18 C measures a flow rate of the cooling water supplied to the condensation unit 17 .
  • the flow meter 18 C is electrically connected to the control device 14 .
  • the flow meter 18 C transmits information on the measured flow rate of the cooling water to the control device 14 .
  • the other end of the first line 19 is connected to an inlet 31 A of the economizer 31 .
  • the liquid refrigerant which is condensed by the condensation unit 17 and whose pressure is reduced to an intermediate pressure is supplied to the inlet 31 A of the economizer 31 through the first line 19 .
  • An orifice 20 constituting the first expansion unit 23 is provided in the first line 19 .
  • the liquid refrigerant generated by the condensation unit 17 passes through the orifice 20 .
  • a diameter of the orifice 20 is set so as to exert desired performance.
  • the bypass line 21 branches off from a portion of the first line 19 positioned between the outlet 17 B and the orifice 20 .
  • a distal end of the bypass line 21 is connected to the first line 19 such that the bypass lines 21 bypasses the orifice 20 .
  • the first expansion unit 23 functions as a high-pressure expansion unit.
  • the first expansion unit 23 has the above-described orifice 20 and a flow regulation valve 22 .
  • the flow regulation valve 22 is provided in the bypass line 21 . Accordingly, the flow regulation valve 22 is connected in parallel to the orifice 20 and is configured to allow a passage of the liquid refrigerant generated by the condensation unit 17 .
  • the flow regulation valve 22 is electrically connected to the control device 14 . Opening and closing (opening degree) of the flow regulation valve 22 are controlled by the control device 14 . Accordingly, the flow regulation valve 22 adjusts a passing amount of the refrigerant condensed by the condensation unit 17 .
  • a partial load peak D T will be described, in which a coefficient of performance (COP) during the partial load operation is maximized.
  • COP coefficient of performance
  • temperatures of the cooling water are different from each other.
  • the temperature of the cooling water of the curve A is highest, and the temperature of the cooling water of the curve E is lowest.
  • the temperature of the cooling water decreases.
  • the coefficient of performance (COP) increases.
  • the partial load peak D T at which the coefficient of performance (COP) is maximized is a peak position of the curve D when the load factor is X % (for example, a predetermined value of 20% or more to 30% or less).
  • the load factor is (the load factor is X % or more and less than 100%) equal to or more than the partial load peak D T at which the coefficient of performance (COP) during the partial load operation is maximized
  • the refrigerant condensed by the condensation unit 17 passes through the orifice 20 and the flow regulation valve 22 configured as described above.
  • the opening degree of the flow regulation valve 22 is regulated by the control device 14 .
  • the adjustment of the opening degree of the flow regulation valve 22 performed by the control device 14 will be described later.
  • the flow regulation valve 22 is fully closed, the refrigerant condensed by the condensation unit 17 passes through only the orifice 20 .
  • the first expansion unit 23 configured as described above reduces the pressure of the condensed liquid refrigerant to an intermediate pressure.
  • the above-described first expansion unit 23 is provided, and thus, when the load factor is equal to or more than the partial load peak D T at which the coefficient of performance (COP) during the partial load operation is maximized, the refrigerant condensed by the condensation unit 17 can pass through the orifice 20 and the flow regulation valve 22 , and when the load factor is less than the partial load peak D T , the flow regulation valve 22 is fully closed, the refrigerant condensed by the condensation unit 17 can pass through only the orifice 20 . Accordingly, it is possible to suppress a decrease in performance of the centrifugal chiller 10 during the partial load operation.
  • COP coefficient of performance
  • the orifice 20 and the flow regulation valve 22 are used together, it is possible to decrease a diameter of the flow regulation valve 22 , and thus, it is possible to decrease a size of the first expansion unit 23 . Accordingly, it is possible to suppress an increase in size of the centrifugal chiller 10 .
  • an electric ball valve may be used as the flow regulation valve 22 .
  • the electric ball valve is used as the flow regulation valve 22 , and thus, it is possible to decrease the diameter of the electric ball valve, and it is possible to suppress the increase in size of the flow regulation valve 22 .
  • the first flow rate detector 26 is provided in a portion of the first line 19 positioned between a connection position 21 A of the bypass line 21 and the orifice 20 .
  • the first flow rate detector 26 is electrically connected to the control device 14 .
  • the first flow rate detector 26 detects a flow rate (hereinafter, referred to as a “first flow rate”) of a liquid refrigerant flowing through the orifice 20 and transmits information of the detected first flow rate to the control device 14 .
  • a flow rate hereinafter, referred to as a “first flow rate”
  • the second flow rate detector 29 is provided in a portion of the bypass line 21 positioned between the connection position 21 A of the bypass line 21 and the flow regulation valve 22 .
  • the second flow rate detector 29 is electrically connected to the control device 14 .
  • the second flow rate detector 29 detects a second flow rate of a liquid refrigerant flowing through the flow regulation valve 22 and transmits information on the detected second flow rate to the control device 14 .
  • the economizer 31 is a gas-liquid separator which functions as an economizer.
  • the economizer 31 separates the liquid refrigerant whose pressure is reduced to the intermediate pressure into the liquid refrigerant and the gas refrigerant.
  • the economizer 31 has the inlet 31 A and outlets 31 B and 31 C.
  • the inlet 31 A is connected to the other end of the first line 19 .
  • the liquid refrigerant whose pressure is reduced to the intermediate pressure by the first expansion unit 23 is introduced into the inlet 31 A.
  • the outlet 31 B is connected to one end of the second line 34 .
  • the outlet 31 B leads the liquid refrigerant to the second line 34 .
  • the outlet 31 C is connected to one end of the line 32 .
  • the outlet 31 C leads the gas refrigerant to the line 32 .
  • the other end of the line 32 is connected to the inlet side of the low stage-side compression unit 51 via the inlet 15 A.
  • the line 32 supplies the gas refrigerant to the low stage-side compression unit 51 .
  • the other end of the second line 34 is connected to an inlet 41 A of the evaporation unit 41 .
  • the liquid refrigerant is supplied to the inlet 41 A of the evaporation unit 41 through the second line 34 .
  • the orifice 35 constituting the second expansion unit 38 is provided in the second line 34 .
  • the liquid refrigerant led out from the economizer 31 passes through the orifice 35 .
  • a diameter of the orifice 35 is set so as to exert desired performance.
  • the bypass line 36 branches off from a portion of the second line 34 positioned between the orifice 35 and the inlet 41 A of the evaporation unit 41 .
  • a distal end of the bypass line 36 is connected to the second line 34 such that the bypass lines 36 bypasses the orifice 35 .
  • the second expansion unit 38 functions as a low-pressure expansion unit.
  • the second expansion unit 38 has the above-described orifice 35 and a flow regulation valve 37 .
  • the flow regulation valve 37 is provided in the bypass line 36 . Accordingly, the flow regulation valve 37 is connected in parallel to the orifice 35 , and the liquid refrigerant which is subjected to the gas-liquid separation by the economizer 31 can pass through the flow regulation valve 37 .
  • the flow regulation valve 37 is electrically connected to the control device 14 . Opening and closing (opening degree) of the flow regulation valve 37 are controlled by the control device 14 . Accordingly, the flow regulation valve 37 adjusts a passing amount of the liquid refrigerant which is subjected to the gas-liquid separation by the economizer 31 .
  • a flow regulation valve for example, electric ball valve
  • a flow regulation valve similar to the above-described flow regulation valve 22 can be used.
  • the load factor is (the load factor is X % or more and less than 100%) equal to or more than the partial load peak D T at which the coefficient of performance (COP) during the partial load operation is maximized
  • the refrigerant condensed by the condensation unit 17 passes through the orifice 35 and the flow regulation valve 37 configured as described above.
  • the opening degree of the flow regulation valve 37 is regulated by the control device 14 .
  • the flow regulation valve 37 is fully closed, the liquid refrigerant passes through only the orifice 35 .
  • the second expansion unit 38 configured as described above decreases the condensed liquid refrigerant to a low pressure.
  • the first flow rate detector 39 is provided in a portion of the second line 34 positioned between a connection position 36 A of the bypass line 36 and the orifice 35 .
  • the first flow rate detector 39 is electrically connected to the control device 14 .
  • the first flow rate detector 39 detects the first flow rate of the liquid refrigerant flowing through the orifice 35 and transmits information on the detected first flow rate to the control device 14 .
  • the second flow rate detector 40 is provided in a portion of the bypass line 36 positioned between the connection position 36 A of the bypass line 36 and the flow regulation valve 37 .
  • the second flow rate detector 40 is electrically connected to the control device 14 .
  • the second flow rate detector 40 detects the second flow rate of the liquid refrigerant flowing through the flow regulation valve 37 and transmits information on the detected second flow rate to the control device 14 .
  • the evaporation unit 41 has the inlet 41 A and an outlet 41 B.
  • the inlet 41 A is connected to the other end of the second line 34 .
  • a low-pressure refrigerant whose pressure is reduced by the second expansion unit 38 is supplied to the inlet 41 A via the second line 34 .
  • the outlet 41 B is connected to one end of the line 43 .
  • a portion of the chilled water circulation line 13 to which the chilled water circulating between the external load 6 and the evaporation unit 41 flows is disposed in the evaporation unit 41 .
  • Heat exchange is performed between the chilled water flowing through the chilled water circulation line 13 and the low-pressure refrigerant by the evaporation unit 41 , and thus, the low-pressure refrigerant is evaporated and the gas refrigerant is generated.
  • the evaporation unit 41 supplies the generated gas refrigerant to the inlet 15 A of the compression unit 15 via the line 43 .
  • the cooling tower 11 cools the cooling water which passes through the condensation unit 17 and whose temperature increases.
  • the cooled cooling water is supplied to the condensation unit 17 via the cooling water circulation line 12 .
  • the cooling water circulation line 12 is connected to the cooling tower 11 and a portion of the cooling water circulation line 12 is accommodated in the condensation unit 17 .
  • the cooling water circulates through the cooling water circulation line 12 between the cooling tower 11 and the condensation unit 17 .
  • the chilled water circulation line 13 is connected to the external load 6 (for example, air conditioner) and a portion of the chilled water circulation line 13 is disposed in the evaporation unit 41 .
  • the chilled water circulates through the chilled water circulation line 13 between the external load 6 and the evaporation unit 41 .
  • the control device 14 will be described with reference to FIGS. 1, 3, and 4 .
  • the control device 14 has a load factor acquisition unit 60 , a compression unit controller 61 , a map storage unit 62 , a flow regulation valve opening degree acquisition unit 64 , and a flow regulation valve controller 66 .
  • the load factor acquisition unit 60 is electrically connected to the inlet temperature detection unit 18 A, the outlet temperature detection unit 18 B, the flow meter 18 C, the compression unit 15 , the compression unit controller 61 , and the flow regulation valve opening degree acquisition unit 64 .
  • the load factor acquisition unit 60 acquires a load capacity based on the cooling water inlet temperature, the cooling water outlet temperature, and the flow rate of the cooling water transmitted from the inlet temperature detection unit 18 A, the outlet temperature detection unit 18 B, and the flow meter 18 C, and acquires a load factor X (%) based on the acquired load capacity.
  • the load factor X (%) is acquired based on the following Expression (1).
  • load factor X (%) ⁇ (load capacity at any time)/(load capacity during rated operation) ⁇ 100 (1)
  • the load factor acquisition unit 60 transmits the information on the acquired load factor X to the compression unit controller 61 and the flow regulation valve opening degree acquisition unit 64 .
  • the compression unit controller 61 is electrically connected to the compression unit 15 .
  • the compression unit controller 61 performs a control to reduce an output of the compression unit 15 when the load factor X (%) decreases.
  • the map storage unit 62 is electrically connected to the flow regulation valve opening degree acquisition unit 64 .
  • Map data (graph data) acquired in the advance as shown in FIG. 4 is stored in the map storage unit 62 .
  • a horizontal axis indicates the load factor (%) of the centrifugal chiller 10
  • one vertical axis indicates the flow rate (kg/min) of the refrigerant
  • the other vertical axis indicates the opening degree (%) of the flow regulation valve.
  • a curve related to the first flow rate of the liquid refrigerant passing through the orifice 20 in a case where the cooling water inlet temperatures are different from each other a curve related to the second flow rate of the liquid refrigerant passing through the flow regulation valve 22 in a case where the cooling water inlet temperatures are different from each other, and a circulation flow rate (straight line) for the liquid refrigerant are shown.
  • the straight line of the “circulation flow rate of the liquid refrigerant” shown in FIG. 4 indicates a total flow rate (the flow rate of the liquid refrigerant introduced into the inlet 31 A) of the refrigerant and a predetermined circulation flow rate corresponding to the load factor.
  • the temperatures in parentheses indicate the cooling water inlet temperatures.
  • (17° C.) means that the cooling water inlet temperature is 17° C.
  • the flow regulation valve opening degree acquisition unit 64 is electrically connected to the inlet temperature detection unit 18 A, the first flow rate detectors 26 and 39 , the second flow rate detectors 29 and 40 , and the flow regulation valve controller 66 .
  • the cooling water inlet temperature and the first and second flow rates of the liquid refrigerant detected by the first flow rate detectors 26 and 39 and the second flow rate detectors 29 and 40 are input to the flow regulation valve opening degree acquisition unit 64 .
  • the opening degree (%) of the flow regulation valve 22 is acquired based on the load factor X (%), the cooling water inlet temperature, the first and second flow rates of the liquid refrigerant detected by the first and second flow rate detectors 26 and 29 , and the map data shown in FIG. 4 .
  • the flow regulation valve opening degree acquisition unit 64 acquires the opening degree (%) of the flow regulation valve 22 which causes a total flow rate of the first flow rate (Kg/min) of the liquid refrigerant (the refrigerant which is a liquid) passing through the first flow rate detector 26 and the second flow rate (Kg/min) of the liquid refrigerant (the refrigerant which is a liquid) passing through the second flow rate detector 29 to be a predetermined circulation flow rate (in this case, W (Kg/min)).
  • the graph of the opening degree of the flow regulation valve 22 used at this time uses a graph in which the temperatures of the cooling water are the same as each other.
  • the opening degree of the flow regulation valve 22 is an opening degree of the flow regulation valve 22 to be acquired at a position at which a dotted line which passes through the load factor X and is parallel to the vertical axis and the graph of the opening degree of the flow regulation valve 22 intersect each other.
  • the opening degree of the flow regulation valve 37 constituting the second expansion unit 38 is acquired using the same method as that of the flow regulation valve 22 described above.
  • the flow regulation valve opening degree acquisition unit 64 transmits the acquired information on the opening degrees of the flow regulation valves 22 and 37 to the flow regulation valve controller 66 .
  • the flow regulation valve controller 66 is electrically connected to the flow regulation valves 22 and 37 .
  • the flow regulation valve controller 66 controls the opening degrees of the flow regulation valves 22 and 37 based on the information on the opening degrees of the flow regulation valves 22 and 37 transmitted from the flow regulation valve opening degree acquisition unit 64 , respectively.
  • a high-pressure refrigerant for example, R134a
  • a low-pressure refrigerant for example, R1233zd
  • the low-pressure refrigerant has a large specific volume as compared to the high-pressure refrigerant which is a subject to a regulation of a high pressure gas. Therefore, for example, if orifices 20 and 35 are not provided and only the flow regulation valves 22 and 37 are provided in the centrifugal chiller 10 , the sizes of the flow regulation valves 22 and 37 increase.
  • the orifices 20 and 35 and the flow regulation valves 22 and 37 are used together, and thus, it is possible to suppress the increase in size of each of the flow regulation valves 22 and 37 .
  • the centrifugal chiller 10 has the first expansion unit 23 including the orifice 20 through which the refrigerant condensed by the condensation unit 17 passes and the flow regulation valve 22 which is connected in parallel to the orifice 20 and can adjust the passing amount of the refrigerant condensed by the condensation unit 17 .
  • the refrigerant condensed by the condensation unit 17 can pass through the orifice 20 and the flow regulation valve 22 , and when the load factor is less than the partial load peak D T , the flow regulation valve 22 is fully closed, and the refrigerant condensed by the condensation unit 17 can pass through only the orifice 20 . Therefore, it is possible to suppress a decrease in performance during the partial load operation.
  • the orifice 20 and the flow regulation valve 22 are used together, and thus, it is possible to decrease the diameter of the flow regulation valve 22 , and it is possible to reduce the size of the first expansion unit 23 . Accordingly, it is possible to prevent the size of the centrifugal chiller 10 from increasing.
  • the second expansion unit 38 disposed between the economizer 31 and the evaporation unit 41 can also obtain the same effect as that of the first expansion unit 23 .
  • the refrigerant condensed by the condensation unit 17 can pass through the orifice 20 and the flow regulation valve 22 , and when the load factor is less than the partial load peak D T , the flow regulation valve 22 is fully closed, and the refrigerant condensed by the condensation unit 17 can pass through only the orifice 20 .
  • the low-pressure liquid refrigerant is supplied to the evaporation unit 41 via the second expansion unit 38 configured similarly to the first expansion unit 23 .
  • the opening degree of the flow regulation valve 22 may be regulated such that a sum of the first and second flow rate is a predetermined circulation flow rate.
  • the external load 6 may use the cooling water which flows through the condensation unit 17 or flows through the cooling water circulation line 12 . That is, the centrifugal chiller 10 shown in FIG. 1 may be used as a heat pump.
  • the economizer 31 is provided is described as an example.
  • the economizer 31 may be provided as needed, and is not an essential configuration.
  • the first line 19 may be connected to the other end and the inlet 41 A. Accordingly, in this case, the second line 34 , the bypass line 36 , the second expansion unit 38 , the first flow rate detector 39 , and the second flow rate detector 40 are not required.
  • the present invention can be applied to a centrifugal chiller and a centrifugal chiller operation method.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)
  • Sorption Type Refrigeration Machines (AREA)
US16/486,454 2017-02-28 2018-01-22 Centrifugal chiller and centrifugal chiller operation method Abandoned US20200232682A1 (en)

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JP2017036285A JP6890021B2 (ja) 2017-02-28 2017-02-28 ターボ冷凍機、及びターボ冷凍機の運転方法
PCT/JP2018/001753 WO2018159150A1 (ja) 2017-02-28 2018-01-22 ターボ冷凍機、及びターボ冷凍機の運転方法

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JPS5970169U (ja) * 1982-10-30 1984-05-12 三菱重工業株式会社 冷凍装置
JPH07310962A (ja) * 1994-05-17 1995-11-28 Mitsubishi Heavy Ind Ltd ヒートポンプ式マルチタイプ空気調和機
DE19852127B4 (de) * 1998-11-12 2008-09-11 Behr Gmbh & Co. Kg Expansionsorgan und hierfür verwendbare Ventileinheit
JP2002286300A (ja) * 2001-03-28 2002-10-03 Mitsubishi Electric Corp 空気調和装置
JP2005098597A (ja) * 2003-09-25 2005-04-14 Tgk Co Ltd 冷凍サイクル
JP2006125793A (ja) * 2004-11-01 2006-05-18 Hitachi Home & Life Solutions Inc 空気調和装置
JP4818154B2 (ja) * 2007-02-15 2011-11-16 三菱電機株式会社 膨張弁機構および流路切り替え装置
JP5244420B2 (ja) * 2008-02-28 2013-07-24 三菱重工業株式会社 ターボ冷凍機および熱源システムならびにこれらの制御方法
CN102422093B (zh) * 2009-05-12 2014-03-19 三菱电机株式会社 空调装置
JP5227919B2 (ja) * 2009-08-12 2013-07-03 日立アプライアンス株式会社 ターボ冷凍機
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JP6487163B2 (ja) * 2014-07-31 2019-03-20 三菱重工サーマルシステムズ株式会社 ターボ冷凍機

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WO2018159150A1 (ja) 2018-09-07

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