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WO2008001667A1 - Dispositif de réfrigération - Google Patents

Dispositif de réfrigération Download PDF

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Publication number
WO2008001667A1
WO2008001667A1 PCT/JP2007/062442 JP2007062442W WO2008001667A1 WO 2008001667 A1 WO2008001667 A1 WO 2008001667A1 JP 2007062442 W JP2007062442 W JP 2007062442W WO 2008001667 A1 WO2008001667 A1 WO 2008001667A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
refrigerant
capacity
compressor
circuit
Prior art date
Application number
PCT/JP2007/062442
Other languages
English (en)
Japanese (ja)
Inventor
Satoru Sakae
Masaaki Takegami
Hiroto Nakajima
Iwao Shinohara
Original Assignee
Daikin Industries, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daikin Industries, Ltd. filed Critical Daikin Industries, Ltd.
Publication of WO2008001667A1 publication Critical patent/WO2008001667A1/fr

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Classifications

    • 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
    • F25B7/00—Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit
    • 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
    • F25B2600/02—Compressor control
    • F25B2600/025—Compressor control by controlling speed
    • F25B2600/0253—Compressor control by controlling speed with variable speed
    • 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
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1931—Discharge pressures
    • 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
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1933—Suction pressures
    • 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
    • F25B2700/2104—Temperatures of an indoor room or compartment
    • 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
    • F25B2700/2106—Temperatures of fresh outdoor air
    • 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
    • F25B2700/21163—Temperatures of a condenser of the refrigerant at the outlet of the condenser
    • 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
    • F25B2700/2117—Temperatures of an evaporator
    • F25B2700/21174—Temperatures of an evaporator of the refrigerant at the inlet of the evaporator
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • the present invention relates to a refrigeration apparatus provided with a supercooling circuit, and particularly to a technology for controlling the capacity of a supercooling circuit.
  • a refrigeration apparatus including a refrigerant circuit that performs a vapor compression refrigeration cycle is known.
  • a main cooling circuit for cooling a space to be cooled is provided with a supercooling circuit including a supercooling heat exchanger for increasing the cooling capacity.
  • a first compressor, a first outdoor heat exchanger, a first expansion valve, and an indoor heat exchanger are sequentially connected by a refrigerant pipe.
  • the second compressor, the second outdoor heat exchanger, the second expansion valve, and the supercooling heat exchanger are sequentially connected by the refrigerant pipe.
  • the supercooling heat exchanger of the supercooling circuit is provided between the first outdoor heat exchanger of the main refrigerant circuit and the first expansion valve. Place in high pressure liquid piping.
  • the supercooling heat exchanger is a heat exchanger that exchanges heat between refrigerants, and includes a first flow path through which the refrigerant in the main refrigerant circuit flows and a second flow path through which the refrigerant in the supercooling circuit flows.
  • the supercooling heat exchanger the high-pressure liquid refrigerant condensed in the first outdoor heat exchanger of the main refrigerant circuit and the low-pressure refrigerant in the supercooling circuit are heat-exchanged, so that the high-pressure liquid refrigerant is superfluid.
  • the degree of supercooling of the high-pressure liquid refrigerant can be increased.
  • Patent Document 1 is cited as a conventional technique for controlling the supercooling circuit in the refrigeration apparatus having the supercooling circuit.
  • the first compressor of the main refrigerant circuit is composed of a variable capacity compressor, and the operating capacity of the first compressor and the low-pressure refrigerant pressure of the main refrigerant circuit are adjusted. Based on this, on / off control of the second compressor of the supercooling circuit is performed. Specifically, the above capacity When the capacity of the variable compressor is equal to or greater than the first predetermined value and the low-pressure refrigerant pressure is equal to or greater than the predetermined value, that is, when the main refrigerant circuit is in a cooling overload state, the second compressor of the supercooling circuit is to start. On the other hand, when the capacity of the variable capacity compressor becomes equal to or lower than a second predetermined value lower than the first predetermined value, the second compressor of the supercooling circuit stops.
  • the start / stop control is performed when the second compressor of the supercooling circuit starts when the main refrigerant circuit is in a cooling overload state, and does not enter the cooling overload state. Is configured to stop.
  • Patent Document 1 Japanese Patent No. 3376844
  • the main refrigerant circuit is in an overload state. Otherwise, the supercooling circuit will not start. That is, the supercooling circuit is merely configured as an auxiliary unit only to compensate for the lack of cooling capacity of the main refrigerant circuit.
  • the main refrigerant circuit is at a higher pressure than normal due to a rise in outside air temperature, and the input to the variable capacity compressor of the main refrigerant circuit becomes excessive, resulting in a decrease in the coefficient of performance. Even in the running operation, if the low-pressure refrigerant pressure in the main refrigerant circuit is maintained, the second compressor of the supercooling circuit of the refrigeration apparatus in Patent Document 1 does not start.
  • the present invention has been made in view of power, and an object of the present invention is to provide a refrigeration apparatus including a supercooling circuit for increasing the cooling capacity, in which the refrigeration apparatus is not in an overload state.
  • the other is to improve the coefficient of performance of the refrigeration system by actively operating the compressor of the supercooling circuit.
  • the first invention provides a variable capacity first compressor (2), a first condenser (6), a supercooling heat exchanger (8), a first expansion mechanism (10), and a first evaporator ( 12) are connected in sequence to perform a refrigeration cycle, a main refrigerant circuit (lb), a second compressor (20), a second condenser (24), a second expansion mechanism (26), and the above supercooling heat exchanger (8) are connected in order to perform a refrigeration cycle (la) and the first compression It assumes a refrigeration system equipped with a first capacity adjusting means capable of adjusting the capacity of the machine (2).
  • the second compressor (20) includes a variable capacity compressor (20), and the main refrigerant circuit
  • first high pressure refrigerant pressure detecting means (5) for detecting the high pressure refrigerant pressure of (lb)
  • second high pressure refrigerant pressure detecting means (23) for detecting the high pressure refrigerant pressure of the supercooling circuit (la)
  • a second capacity adjusting means capable of adjusting the capacity of the second compressor (20), and controlling the first capacity adjusting means and the second capacity adjusting means to control the main refrigerant circuit (lb). It is characterized by comprising high-pressure equivalent control means (32) for bringing the high-pressure refrigerant pressure value close to the high-pressure refrigerant pressure value of the supercooling circuit (la).
  • the high-pressure equivalent control means (32) can reduce the capacity of the first compressor (2) with the high-pressure refrigerant pressure of the supercooling circuit (la) as a target value.
  • the high-pressure equivalent control means (32) can increase the capacity of the second compressor (20) with the high-pressure refrigerant pressure in the main refrigerant circuit (lb) as a target value. Thereby, the high-pressure refrigerant pressure values of the main refrigerant circuit (lb) and the supercooling circuit (la) can be made closer.
  • the cooling capacity of the main refrigerant circuit (lb) when both of the high-pressure refrigerant pressure values approach the capacity of the first compressor (2) decreases, so that the main refrigerant circuit ( The amount of refrigerant flowing into the first evaporator (12) of lb) decreases, and the cooling capacity of the main refrigerant circuit (lb) decreases.
  • the capacity of the second compressor (20) increases, the supercooling capacity in the supercooling heat exchanger (8) of the main refrigerant circuit (1 b) increases, and the main refrigerant circuit (lb ), The degree of supercooling of the refrigerant flowing through it increases. This expansion of the degree of supercooling increases the cooling capacity of the main refrigerant circuit (lb).
  • a second invention comprises, in the first invention, an outlet liquid temperature detecting means (9) for detecting a refrigerant outlet liquid temperature on the main refrigerant circuit (lb) side of the supercooling heat exchanger (8).
  • the high-pressure equivalent control means (32) increases the capacity of the second compressor (20) by controlling the second capacity adjusting means if the refrigerant outlet liquid temperature is higher than a predetermined value, If it is lower than the value, the second capacity adjusting means is controlled to reduce the capacity of the second compressor (20).
  • the set value at the refrigerant outlet liquid temperature of the main refrigerant circuit (lb), which is obtained only by the high pressure refrigerant pressure value of the main refrigerant circuit (lb), is used as a target value, and
  • the first control unit of the stage (32) can control the capacity of the second compressor (20).
  • a third invention is the first or second invention, comprising suction refrigerant pressure detection means (28) for detecting the suction refrigerant pressure of the second compressor (20), wherein the high-pressure equivalent control means (32) controls the second capacity adjusting means to increase the capacity of the second compressor (20) if the suction refrigerant pressure is higher than a predetermined value, and if the suction refrigerant pressure is lower than the predetermined value, It is characterized by comprising a second control unit that controls the adjusting means to reduce the capacity of the second compressor (20).
  • the suction of the second compressor (20) includes only the high-pressure refrigerant pressure value of the main refrigerant circuit (lb) and the set value of the refrigerant outlet liquid temperature of the main refrigerant circuit (lb).
  • the second controller of the high-pressure equivalent control means (32) can control the capacity of the second compressor (20) using the set value for the refrigerant pressure as a target value.
  • a fourth invention is the four inventions according to any one of the first to third powers, further comprising an evaporation temperature detecting means (11) for detecting an evaporation temperature of the main refrigerant circuit (lb), wherein the high-pressure equivalent control means (32) If the evaporation temperature is lower than a predetermined value, the first capacity adjustment means is controlled to reduce the capacity of the first compressor (2), and if higher than the predetermined value, the first capacity adjustment is performed.
  • a third control unit that increases the capacity of the first compressor (2) by controlling the means is provided.
  • the high-pressure equivalent control means (32) using as a target a set value at the evaporation temperature of the main refrigerant circuit (lb), which is not only the high-pressure refrigerant pressure value of the supercooling circuit (la).
  • the third control unit can control the capacity of the first compressor (2).
  • the supercooling circuit (la) by performing the high-pressure equivalent control, the supercooling circuit (la) until the high-pressure refrigerant pressure of the supercooling circuit (la) approaches the high-pressure refrigerant pressure of the main refrigerant circuit (lb).
  • the second compressor (20) of a) can be operated.
  • the main refrigerant circuit (lb) and the supercooling circuit (la) can be shared.
  • the sharing of the cooling load the decrease in the cooling capacity of the main refrigerant circuit (lb) due to the decrease in the capacity of the first compressor (2) It becomes a configuration to compensate for the increase in cooling capacity due to the increase in capacity.
  • the increase in the electric input due to the increase in the capacity of the second compressor (20) is the decrease in the electric input of the first compressor (2) due to the decrease in the cooling capacity of the main refrigerant circuit (lb). Smaller than. This is because the coefficient of performance of the supercooling circuit (la) is larger than the coefficient of performance of the main refrigerant circuit (lb).
  • the reason why the coefficient of performance of the supercooling circuit (la) is larger than that of the main refrigerant circuit (lb) is that, for example, when the set temperature of the cooling target space is -30 ° C, the main refrigerant circuit (lb) The evaporation saturation temperature is around 140 ° C, the evaporation saturation temperature of the supercooling circuit (la) is around 0 ° C, and the low-pressure refrigerant pressure in the supercooling circuit (la) is high.
  • the cooling operation is not performed only by the main refrigerant circuit (lb) having a small coefficient of performance.
  • the cooling operation is shared by the main refrigerant circuit (lb) and the supercooling circuit (la) having a large coefficient of performance. By performing this, the total coefficient of performance of the refrigeration apparatus can be improved.
  • the first controller of the high-pressure equivalent control can limit an increase in capacity in the second compressor (20).
  • the reason for limiting the increase in the capacity of the second compressor (20) is that when the capacity of the second compressor (20) is increased, the high-pressure refrigerant pressure in the supercooling circuit (la) increases. This is because the supercooling capacity of the supercooling heat exchanger (8) is increased and the refrigerant outlet liquid temperature of the supercooling heat exchanger (8) of the main refrigerant circuit (lb) is also lowered.
  • the high-pressure equivalent means increases the capacity of the second compressor (20) by using only the high-pressure refrigerant pressure of the main refrigerant circuit (lb) as a target value, depending on conditions, It is conceivable that the above-mentioned refrigerant outlet liquid temperature is excessively lower than necessary. Therefore, in order to prevent the refrigerant outlet liquid temperature from dropping too much, the first control unit limits the increase in capacity of the second compressor (20).
  • the second controller of the high pressure equivalent control can limit an increase in capacity in the second compressor (20).
  • the reason for limiting the increase in the capacity of the second compressor (20) is that when the capacity of the second compressor (20) is increased, the high-pressure refrigerant pressure in the supercooling circuit (la) increases. ,Up This is because the suction refrigerant pressure of the second compressor (20) also decreases.
  • the high pressure equivalent means increases the capacity of the second compressor (20) with only the high pressure refrigerant pressure of the main refrigerant circuit (lb) as a target value as in the first invention
  • the suction refrigerant pressure is too low. Therefore, in order to prevent the suction refrigerant pressure from dropping too much, the second control unit limits the increase in capacity of the second compressor (20).
  • the third controller of the high pressure equivalent control has a capacity of the first compressor (2) based on the evaporation temperature.
  • the reduction can be limited.
  • the reason for limiting the capacity reduction of the first compressor (2) is that when the capacity of the first compressor (2) is decreased, the cooling capacity of the main refrigerant circuit (lb) decreases and the cooling capacity of the first compressor (2) decreases. This is because the target space is insufficiently cooled.
  • the high-pressure equivalent means when the high-pressure equivalent means reduces the capacity of the first compressor (2) by using only the high-pressure refrigerant pressure of the supercooling circuit (la) as a target value, depending on the conditions, It is conceivable that the evaporation temperature is too high. Therefore, in order to prevent the intake refrigerant pressure from rising excessively, the three control units limit the decrease in the capacity of the first compressor (2). As a result, the high-pressure equivalent control means (32) can perform high-pressure equivalent control while maintaining the cooling capacity of the main refrigerant circuit (lb).
  • FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to an embodiment.
  • FIG. 2 is a control flow diagram of the refrigeration apparatus according to the embodiment.
  • FIG. 3 is a table showing the relationship between the condensation temperature of the main refrigerant circuit and the subcooling circuit and the coefficient of performance of the refrigeration apparatus.
  • Second variable capacity compressor (second compressor)
  • Second high-pressure refrigerant pressure sensor (second high-pressure refrigerant pressure detection means)
  • Second low-pressure refrigerant pressure sensor (intake refrigerant pressure detection means)
  • FIG. 1 is a refrigerant circuit diagram of the refrigeration apparatus according to this embodiment.
  • This refrigeration apparatus is for cooling a space to be cooled (for example, a freezing room).
  • the refrigeration apparatus includes a main refrigerant circuit (lb) for cooling the space to be cooled, and a supercooling heat exchanger (8) for cooling the refrigerant (high-pressure liquid refrigerant) flowing through the main refrigerant circuit (lb). And a supercooling circuit (la).
  • the refrigerating apparatus is provided with a controller (high pressure equivalent control means) (32) for controlling the operation of the main refrigerant circuit (lb) and the supercooling circuit (la).
  • the main refrigerant circuit (lb) includes a first variable capacity compressor (first compressor) (2), a first outdoor heat exchanger (first condenser) (6), and the supercooling heat exchanger ( 8) and the first expansion valve (first expansion mechanism) (10) and the indoor heat exchanger (first evaporator) (12) are connected in order by refrigerant piping so that a vapor compression refrigeration cycle is performed. It is composed.
  • An inverter (not shown) is connected to the first variable capacity compressor (2).
  • the inverter supplies current to the first variable capacity compressor (2) and supplies the current.
  • the flow frequency can be changed. That is, the capacity of the first variable capacity compressor (2) can be freely changed within a certain range by the inverter.
  • the first suction refrigerant pipe (15) is connected to the suction side of the first variable displacement compressor (2), and the first discharge refrigerant pipe (3) is connected to the discharge side.
  • the first suction refrigerant pipe (15) is provided with a first suction temperature sensor (17) and a first low-pressure refrigerant pressure sensor (16).
  • the first discharge refrigerant pipe (3) is provided with a first discharge temperature sensor (4) and a first high-pressure refrigerant pressure sensor (first high-pressure refrigerant pressure detection means) (5).
  • the first discharge refrigerant pipe (3) connects the first variable capacity compressor (2) and the first outdoor heat exchanger (6).
  • the first outdoor heat exchanger (6) is a cross-fin type fin-and-tube heat exchanger, and in the vicinity of the first outdoor heat exchanger (6) One blower fan (6a) and a first outside air temperature sensor (6b) are provided. Although not shown, in the first outdoor heat exchanger (6), the heat transfer tubes are arranged in a plurality of paths, and a large number of aluminum fins are installed perpendicular to the heat transfer tubes.
  • the first high-pressure liquid refrigerant pipe (7) connecting the first outdoor heat exchanger (6) and the first expansion valve (10) is provided with the supercooling heat exchanger (8). Yes.
  • the supercooling heat exchanger (8) is composed of a plate fin type heat exchanger, and the first and second flow paths (8a, 8b) are provided in the pre-fin type heat exchanger. Is formed.
  • the refrigerant circulating in the main refrigerant circuit (lb) flows through the first flow path (8a), and the refrigerant circulating through the supercooling circuit (la) flows through the second flow path (8b).
  • the refrigerant exchanges heat to cool the refrigerant flowing on the main refrigerant circuit (lb) side.
  • a refrigerant outlet liquid temperature sensor (9) (outlet liquid temperature detecting means) for measuring the temperature of the outlet side of the supercooling heat exchanger (8) for the refrigerant flowing through the main refrigerant circuit (1b) side is provided.
  • the refrigerant pipe for connecting the supercooling heat exchanger (8) and the first expansion valve (10) of the main refrigerant circuit (lb) is provided.
  • the first expansion valve (10) is an electric expansion valve whose opening degree can be adjusted, and the opening degree can be appropriately changed by an electric signal.
  • the indoor heat exchanger (12) is a cross-fin type fin-and-tube heat exchanger. Although not shown, the heat transfer tubes are arranged in a plurality of paths, and a number of aluminum fins are installed perpendicular to the heat transfer tubes.
  • the An evaporation temperature sensor (evaporation temperature detecting means) (11) is provided on the inlet side of the indoor heat exchanger (12), and a third blower fan (12a) is provided near the indoor heat exchanger (12). ) And an indoor temperature sensor (12b).
  • the indoor heat exchanger (12) and the first variable capacity compressor (2) are connected by the first suction refrigerant pipe (15).
  • the main refrigerant circuit (lb) is provided with a liquid injection pipe (18), and one end of the liquid injection pipe (18) is connected to the first outdoor heat exchanger (6) and the excess refrigerant. Connected to the first high-pressure liquid refrigerant pipe (7) between the cooling heat exchanger (8) and the other end between the indoor heat exchanger (12) and the first variable capacity compressor (2). It is connected to the first suction refrigerant pipe (15).
  • the liquid injection pipe (18) is provided with a pressure reducing valve (19) for reducing the pressure of the refrigerant flowing through the liquid injection pipe (18).
  • the supercooling circuit (la) consists of a second variable capacity compressor (20), a second outdoor heat exchanger (second condenser) (24), and a second expansion valve (second expansion mechanism) (26). And the supercooling heat exchanger (8) are sequentially connected by a refrigerant pipe so as to perform a vapor compression refrigeration cycle.
  • the second variable capacity compressor (20) is connected to an inverter (not shown).
  • the capacity of the second variable capacity compressor (20) can be freely changed within a certain range.
  • a second suction refrigerant pipe (30) is connected to the suction side of the second variable capacity compressor (20), and a second discharge refrigerant pipe (21) is connected to the discharge side.
  • the second suction refrigerant pipe (30) is provided with a second suction temperature sensor (29) and a second low-pressure refrigerant pressure sensor (suction refrigerant pressure detection means) (28).
  • the second discharge refrigerant pipe (21) is provided with a second discharge temperature sensor (22) and a second high-pressure refrigerant pressure sensor (second high-pressure refrigerant pressure detection means) (23).
  • the second discharge refrigerant pipe (21) connects the second variable capacity compressor (20) and the second outdoor heat exchanger (24).
  • the second outdoor heat exchanger (24) is a cross-fin type fin-and-tube heat exchanger similar to the first outdoor heat exchanger (6) of the main refrigerant circuit (lb). In the vicinity of the second outdoor heat exchanger (24), a second blower fan (21 ⁇ 2) and a second outside air temperature sensor (24b) are provided. Although not shown, the second outdoor heat exchanger (24) has a plurality of heat transfer tubes. It is arranged in several passes, and a large number of aluminum fins are installed perpendicular to the heat transfer tubes. The second outdoor heat exchanger (24) and the second expansion valve (26) are connected by a second high-pressure liquid refrigerant pipe (25).
  • the second expansion valve (26) is an electric expansion valve whose opening degree can be adjusted, and the opening degree can be appropriately changed by an electric signal.
  • the second expansion valve (26) and the supercooling heat exchanger (8) are connected by a second low-pressure refrigerant pipe (27).
  • the supercooling heat exchanger (8) is composed of a plate fin type heat exchanger, and the second channel (8b) in the plate fin type heat exchanger has a second channel (8b). 2 Low pressure refrigerant pipe (27) is connected.
  • the controller (32) includes a refrigerant outlet liquid temperature sensor (9), an evaporation temperature sensor (11), a first high-pressure refrigerant pressure sensor (5), and a second high-pressure refrigerant pressure sensor (23) provided in the refrigeration apparatus.
  • the high-pressure equivalent control operation of the first variable capacity compressor (2) and the second variable capacity compressor (20) is performed. Yes.
  • the operation of the refrigeration apparatus of this embodiment will be described. First, the cooling operation of the main refrigerant circuit (lb) and the supercooling circuit (la) will be described, and then the high-pressure equivalent control operation in the main refrigerant circuit (lb) and the supercooling circuit (la) will be described.
  • the refrigerant circulates in the circuit using the first outdoor heat exchanger (6) as a condenser and the indoor heat exchanger (12) as an evaporator.
  • the opening of the expansion valve (10) is adjusted to perform the vapor compression refrigeration cycle. Further, the opening degree of the pressure reducing valve (19) of the liquid injection pipe (18) is adjusted according to the operating state.
  • the supercooled high-pressure liquid refrigerant flows into the first expansion valve (10).
  • the high-pressure liquid refrigerant that has flowed into the first expansion valve (10) is reduced in pressure when passing through the first expansion valve (10), becomes a low-pressure liquid refrigerant, and flows into the indoor heat exchanger (12).
  • the low-pressure liquid coolant flowing into the indoor heat exchanger (12) absorbs heat from the air in the space to be cooled when passing through the indoor heat exchanger (12).
  • the low-pressure liquid refrigerant that has absorbed heat from the air in the space to be cooled evaporates into a low-pressure gas refrigerant and flows out of the indoor heat exchanger (12).
  • the low-pressure gas refrigerant that has flowed out of the indoor heat exchanger (12) passes through the first suction refrigerant pipe (15) and flows into the first variable capacity compressor (2).
  • the low-pressure gas refrigerant that has flowed into the first variable capacity compressor (2) is compressed to become high-pressure gas refrigerant, and is discharged from the first variable capacity compressor (2) again.
  • the refrigerant circulates in the main refrigerant circuit (lb) to cool the space to be cooled.
  • the refrigerant circulates in the circuit using the second outdoor heat exchanger (24) as a condenser and the supercooling heat exchanger (8) as an evaporator.
  • the opening degree of the expansion valve (26) is adjusted to perform the vapor compression refrigeration cycle.
  • the high-pressure liquid refrigerant flows out of the second outdoor heat exchanger (24) and flows into the second expansion valve (26).
  • the high-pressure liquid refrigerant flowing into the second expansion valve (26) is reduced in pressure when passing through the second expansion valve (26) to become a low-pressure liquid refrigerant, and the second flow of the supercooling heat exchanger (8).
  • the low-pressure liquid refrigerant flowing into the second flow path of the supercooling heat exchanger (8) flows through the first flow path when passing through the second flow path of the supercooling heat exchanger (8). Absorbs heat from the high-pressure liquid refrigerant in the main refrigerant circuit (lb).
  • the low-pressure liquid refrigerant in the second flow path that has absorbed heat from the high-pressure liquid refrigerant in the first flow path evaporates to become a low-pressure gas refrigerant and flows out of the supercooling heat exchanger (8).
  • the low-pressure gas refrigerant that has flowed out of the supercooling heat exchanger (8) passes through the second suction refrigerant pipe (30) and passes through the second possible refrigerant. It flows into the variable capacity compressor (20).
  • the low-pressure gas refrigerant flowing into the second variable capacity compressor (20) is compressed to become high-pressure gas refrigerant, and is discharged from the second variable capacity compressor (20) again.
  • the refrigerant circulates in the supercooling circuit (la), and the high-pressure liquid coolant in the main refrigerant circuit (lb) is cooled.
  • the high pressure equivalent control means that the main refrigerant circuit (lb) and the supercooling circuit are controlled by performing capacity control by increasing / decreasing the operating frequency of the first and second variable capacity compressors (2, 20). This is a control that adjusts the high-pressure refrigerant pressure with (la) to equalize both high-pressure refrigerant pressures.
  • step ST1 the first outside air temperature sensor
  • the high-pressure refrigerant pressure P1 detected by the first high-pressure refrigerant pressure sensor (5) in the main refrigerant circuit (lb) is detected by the second high-pressure refrigerant pressure sensor (23) in the supercooling circuit (la). Determine whether pressure is greater than P2.
  • step ST8 If the high-pressure refrigerant pressure P1 is less than or equal to the high-pressure refrigerant pressure P2, the process proceeds to the normal control in step ST8 and returns to step 1 again without performing high-pressure equivalent control. On the other hand, when the high-pressure refrigerant pressure P1 is higher than the high-pressure refrigerant pressure P2, the process proceeds to step ST2.
  • the supercooling heat exchanger (8) has a supercooling capacity that is not increased so that the supercooling heat exchanger (8) and the second variable capacity compressor (20) do not malfunction. I have to.
  • step ST3 the frequency of the second variable capacity compressor (20) decreases.
  • the supercooling capacity of the supercooling heat exchanger (8) decreases, so that the refrigerant outlet liquid temperature T1 and the low pressure refrigerant pressure P3 rise, and the freezing puncture of the supercooling heat exchanger (8) occurs.
  • the high-pressure refrigerant pressure PS in the supercooling circuit (la) is lowered, and the process proceeds to step ST5.
  • step ST4 the frequency of the second variable capacity compressor (20) is increased.
  • the supercooling capacity of the supercooling heat exchanger (8) increases, so that the refrigerant outlet liquid temperature T1 and the low pressure refrigerant pressure P3 drop while the high pressure refrigerant pressure of the supercooling circuit (la) is reduced. While PS increases, go to step ST5.
  • step ST6 the frequency of the first variable capacity compressor (2) is increased.
  • the cooling capacity of the indoor heat exchanger (12) is increased, so that the evaporation temperature Te is lowered, while the high-pressure refrigerant pressure P1 of the main refrigerant circuit (lb) is increased, while the step is repeated.
  • step ST7 the frequency of the first variable capacity compressor (2) decreases. This thus, the cooling capacity of the indoor heat exchanger (12) is reduced, so that the evaporation temperature Te is increased while the high-pressure refrigerant pressure P1 of the main refrigerant circuit (lb) is decreased, but the process returns to step ST1. Return.
  • the high-pressure equivalent control operation is performed by repeating the above operation.
  • the refrigeration apparatus performs the high-pressure equivalent control operation until the high-pressure refrigerant pressure in the supercooling circuit (la) approaches the high-pressure refrigerant pressure in the main refrigerant circuit (lb).
  • the second compressor (20) in the supercooling circuit (la) can be actively operated. As a result, even if the main refrigerant circuit (lb) is not overloaded, the second compressor (20) of the supercooling circuit (la) can be operated. As a result, the cooling load of the refrigeration apparatus can be reduced. It can be shared by the main refrigerant circuit (lb) and the supercooling circuit (la).
  • the coefficient of performance of the refrigeration apparatus can be improved by sharing the cooling load of the refrigeration apparatus between the main refrigerant circuit (lb) and the subcooling circuit (la).
  • the reason why the coefficient of performance is improved will be described with reference to FIG. 3 showing the refrigeration cycle simulation results of the main refrigerant circuit (lb) and the supercooling circuit (la) of the present embodiment.
  • the evaporation temperature in the indoor heat exchanger (12) of the main refrigerant circuit (lb) is -40 ° C
  • the supercooling heat exchanger (8) of the supercooling circuit (la) is The evaporating temperature is 0 ° C
  • the cooling capacity of the refrigeration system is constant at 25.2 Kw
  • the condensation temperature of the main refrigerant circuit (lb) and subcooling circuit (la) is changed. The effect of coefficient of performance due to changes was investigated.
  • A is the case where the cooling operation of the refrigeration apparatus is performed only in the main refrigerant circuit (lb), and B and C are the cases where the main refrigerant circuit (lb) and the supercooling circuit (la) are performed. It is.
  • A is the condensation temperature of the main refrigerant circuit (lb) is 50 ° C
  • B is the condensation temperature of the main refrigerant circuit (lb) and the subcooling circuit (la) is 47 ° C and 42 ° C, respectively.
  • the condensation temperature of the refrigerant circuit (lb) and supercooling circuit (la) is 45 ° C.
  • the cooling operation is not performed only with the main refrigerant circuit (lb) having a small coefficient of performance.
  • the high-pressure equivalent control operation is performed with the main refrigerant circuit (lb) and the supercooling circuit (la) having a large coefficient of performance.
  • the performance coefficient of the refrigeration apparatus can be improved by doing so.
  • the main refrigerant circuit (lb) may be a refrigerant circuit that performs a two-stage compression refrigeration cycle, and a plurality of the indoor heat exchangers (12) are installed in parallel. Moyore.
  • the supercooling heat exchanger (8) may be a double pipe type or a shell and tube type heat exchanger that does not need to be a plate type heat exchanger.
  • the present invention relates to a refrigeration apparatus including a supercooling circuit, and is particularly useful for a capacity control technique for the supercooling circuit.

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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)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Abstract

L'invention concerne un dispositif de réfrigération présentant un circuit de surfusion (1a) permettant de renforcer la capacité de refroidissement et un circuit réfrigérant principal (1b) permettant de refroidir un espace de refroidissement cible. Même si le dispositif de réfrigération n'est pas en condition de surcharge, une commande équivalente haute pression par laquelle la pression d'un réfrigérant haute pression dans le circuit réfrigérant principal (1b) et la pression d'un réfrigérant haute pression dans le circuit de surfusion (1a) sont rendues similaires, est réalisée pour améliorer le coefficient de performance du dispositif de réfrigération. Une telle commande est réalisée à l'aide d'un second compresseur à déplacement variable (20) permettant de commander la capacité de surfusion du circuit de surfusion (1a).
PCT/JP2007/062442 2006-06-30 2007-06-20 Dispositif de réfrigération WO2008001667A1 (fr)

Applications Claiming Priority (2)

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JP2006182145A JP4096984B2 (ja) 2006-06-30 2006-06-30 冷凍装置
JP2006-182145 2006-06-30

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WO2011041374A3 (fr) * 2009-09-30 2011-07-14 Thermo Fisher Scientific (Asheville) Llc Système frigorifique doté d'un compresseur à vitesse variable
WO2020071294A1 (fr) * 2018-10-02 2020-04-09 ダイキン工業株式会社 Dispositif à cycle frigorifique

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JP5228661B2 (ja) * 2008-07-17 2013-07-03 ダイキン工業株式会社 冷凍装置
JP5585003B2 (ja) * 2009-05-27 2014-09-10 三洋電機株式会社 冷凍装置
CN101832691B (zh) * 2010-04-12 2012-08-22 大连三洋压缩机有限公司 风冷型沉浸式冷冻装置及冷冻装置的控制方法
US9239174B2 (en) * 2011-02-17 2016-01-19 Rocky Research Cascade floating intermediate temperature heat pump system
TWI568984B (zh) * 2011-09-09 2017-02-01 Topre Corp Gas - liquid heat exchange type refrigeration device

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JPH11182953A (ja) * 1997-12-22 1999-07-06 Daikin Ind Ltd 冷凍装置
JP2007232245A (ja) * 2006-02-28 2007-09-13 Mitsubishi Electric Corp 冷凍システムおよび冷凍システムの運転方法

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JPS58148572U (ja) * 1982-03-30 1983-10-05 三菱電機株式会社 冷凍装置
JPH11182953A (ja) * 1997-12-22 1999-07-06 Daikin Ind Ltd 冷凍装置
JP2007232245A (ja) * 2006-02-28 2007-09-13 Mitsubishi Electric Corp 冷凍システムおよび冷凍システムの運転方法

Cited By (13)

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Publication number Priority date Publication date Assignee Title
US10816243B2 (en) 2009-09-30 2020-10-27 Thermo Fisher Scientific (Asheville) Llc Refrigeration system having a variable speed compressor
US8011191B2 (en) 2009-09-30 2011-09-06 Thermo Fisher Scientific (Asheville) Llc Refrigeration system having a variable speed compressor
US9835360B2 (en) 2009-09-30 2017-12-05 Thermo Fisher Scientific (Asheville) Llc Refrigeration system having a variable speed compressor
EP3351872A1 (fr) * 2009-09-30 2018-07-25 Thermo Fisher Scientific (Asheville) LLC Système de réfrigération ayant un compresseur à vitesse variable
US10072876B2 (en) 2009-09-30 2018-09-11 Thermo Fisher Scientific (Asheville) Llc Refrigeration system having a variable speed compressor
US10845097B2 (en) 2009-09-30 2020-11-24 Thermo Fisher Scientific (Asheville) Llc Refrigeration system having a variable speed compressor
WO2011041374A3 (fr) * 2009-09-30 2011-07-14 Thermo Fisher Scientific (Asheville) Llc Système frigorifique doté d'un compresseur à vitesse variable
JP2020056538A (ja) * 2018-10-02 2020-04-09 ダイキン工業株式会社 冷凍サイクル装置
WO2020071294A1 (fr) * 2018-10-02 2020-04-09 ダイキン工業株式会社 Dispositif à cycle frigorifique
CN112840163A (zh) * 2018-10-02 2021-05-25 大金工业株式会社 冷冻循环装置
JP7193706B2 (ja) 2018-10-02 2022-12-21 ダイキン工業株式会社 冷凍サイクル装置
CN112840163B (zh) * 2018-10-02 2023-02-28 大金工业株式会社 冷冻循环装置
US12007150B2 (en) 2018-10-02 2024-06-11 Daikin Industries, Ltd. Refrigeration cycle device

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TW200817643A (en) 2008-04-16
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