WO2018229826A1 - 冷凍サイクル装置 - Google Patents

冷凍サイクル装置 Download PDF

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Publication number
WO2018229826A1
WO2018229826A1 PCT/JP2017/021631 JP2017021631W WO2018229826A1 WO 2018229826 A1 WO2018229826 A1 WO 2018229826A1 JP 2017021631 W JP2017021631 W JP 2017021631W WO 2018229826 A1 WO2018229826 A1 WO 2018229826A1
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WO
WIPO (PCT)
Prior art keywords
refrigerant
compressor
valve
defrost
refrigeration cycle
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Application number
PCT/JP2017/021631
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English (en)
French (fr)
Japanese (ja)
Inventor
寛也 石原
純 三重野
Original Assignee
三菱電機株式会社
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 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2017/021631 priority Critical patent/WO2018229826A1/ja
Priority to CN201780091251.7A priority patent/CN110709649B/zh
Priority to JP2019524563A priority patent/JP6707195B2/ja
Publication of WO2018229826A1 publication Critical patent/WO2018229826A1/ja

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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
    • 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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles

Definitions

  • the present invention relates to a refrigeration cycle apparatus.
  • the present invention relates to defrost (defrosting) in an apparatus using a non-azeotropic refrigerant as the refrigerant.
  • a refrigeration cycle apparatus there is a method in which defrosting is performed by performing a defrost operation in which a gas (gas) -like refrigerant (hot gas) discharged from a compressor is passed through an evaporator having frost.
  • a gas (gas) -like refrigerant (hot gas) discharged from a compressor is passed through an evaporator having frost.
  • a refrigeration cycle apparatus in which a hot gas bypass pipe is installed between a compressor and an evaporator has been proposed (see, for example, Patent Document 1).
  • the hot gas discharged from a compressor is directly flowed in into an evaporator via hot gas bypass piping.
  • control based on the discharge superheat degree of the discharged refrigerant and the discharge pressure is performed.
  • a non-azeotropic refrigerant in which a plurality of refrigerants are mixed may be used for the refrigerant circuit. Since non-azeotropic refrigerants have different boiling points, it is difficult to obtain a high discharge temperature. Therefore, when performing defrosting with hot gas, there is a problem that it is difficult to secure a large amount of heat (defrosting heat amount) related to defrosting, and it takes time.
  • the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a refrigeration cycle apparatus that can shorten the time of defrosting operation using hot gas.
  • a refrigeration cycle apparatus is a refrigeration cycle apparatus having a refrigerant circuit in which a compressor, a condenser, an expansion valve, an evaporator, and an accumulator are connected in series with a pipe, and a non-azeotropic refrigerant is circulated.
  • An oil return pipe that has an oil return pipe that returns the refrigeration oil in the liquid refrigerant accumulated in the compressor to the compressor, and an on-off valve that is installed on the oil return pipe and controls the amount of refrigeration oil flowing from the accumulator to the compressor
  • the defrost control unit waits after starting the defrost operation. Since the oil return adjuster is closed for the set time and the control to open the oil return adjuster is performed when the standby set time elapses, the liquid refrigerant can be positively stored in the accumulator 8. .
  • a refrigerant having a low discharge temperature is left as a liquid refrigerant in the accumulator, and a large amount of refrigerant having a high discharge temperature is discharged from the compressor, so that a large amount of defrost heat can be secured.
  • Time can be shortened.
  • FIG. 1 is a diagram showing a configuration of a refrigeration cycle apparatus 100 according to Embodiment 1 of the present invention. Based on FIG. 1, the apparatus structure etc. of the refrigerating-cycle apparatus 100 are demonstrated.
  • the refrigeration cycle apparatus 100 performs cooling of a target space, cooling of an object, and the like using a refrigeration cycle (heat pump cycle) that circulates refrigerant.
  • the compressor 1, the condensers 4a and 4b, the expansion valve 6 and the evaporator 7 are connected by piping to form a refrigerant circuit.
  • the refrigerant circuit is not limited to the configuration shown in FIG.
  • the evaporator 7 is built in a cooler casing (not shown).
  • a non-azeotropic refrigerant is used as the refrigerant.
  • the non-azeotropic refrigerant is a refrigerant in which a plurality of refrigerants having different boiling points are mixed.
  • the plurality of refrigerants have different pressures in the refrigerant circuit.
  • a low-pressure refrigerant with a low pressure has a lower specific heat ratio, and therefore has a lower discharge temperature than a high-pressure refrigerant with a high pressure. For this reason, the discharge temperature of the non-azeotropic refrigerant containing the low-pressure refrigerant is lower than that of the single high-pressure refrigerant.
  • the non-azeotropic refrigerant may or may not have flammability.
  • the non-azeotropic refrigerant mixture is, for example, R407C or R448A.
  • the ratio XR32 (wt%) of R32 is 33 ⁇ XR32 ⁇ 39
  • the ratio XR125 (wt%) of R125 is 27 ⁇ XR125 ⁇ 33
  • the ratio XR134a (wt%) of R134a is The condition of 11 ⁇ XR134a ⁇ 17
  • the ratio of R1234yf XR1234yf (wt%) is the condition of 11 ⁇ XR1234yf ⁇ 17
  • the ratio of CO 2 XCO 2 (wt%) is 3 ⁇ XCO 2 ⁇ 9.
  • the compressor 1 sucks the refrigerant, compresses the sucked refrigerant, and discharges it in a high temperature and high pressure state.
  • it has an inverter circuit and has a configuration in which the capacity is controlled by controlling the number of revolutions of a motor included in the compressor 1.
  • the discharge temperature by the adiabatic compression of the sucked gas refrigerant becomes higher as the refrigerant has a larger specific heat ratio.
  • the oil separator 2 has a function of separating the refrigerating machine oil discharged together with the gaseous refrigerant (gas refrigerant) discharged from the compressor 1 from the gas refrigerant.
  • the refrigerating machine oil separated in the oil separator 2 is returned to the compressor 1 from a capillary tube (not shown) connected to the compressor 1.
  • the condenser 4a and the condenser 4b perform heat exchange between the air supplied from the condenser fan 5a and the condenser fan 5b and the refrigerant, and condense and liquefy the refrigerant.
  • the condenser 4 a and the condenser 4 b are connected to the discharge side of the oil separator 2 via the check valve 3.
  • FIG. 1 illustrates the case where two condensers 4a and 4b are connected in parallel, any one having at least one condenser may be used.
  • the expansion valve 6 serves as a throttle device (flow control device) that expands the refrigerant by decompressing it.
  • the evaporator 7 exchanges heat between the air and the refrigerant to evaporate the refrigerant.
  • the blower fan 7 a sends air to the evaporator 7 and promotes heat exchange in the evaporator 7.
  • the accumulator 8 stores liquid refrigerant that is liquid refrigerant that has flowed out of the evaporator 7.
  • the accumulator 8 is connected by piping between the evaporator 7 and the suction side of the compressor 1. Therefore, the gaseous gaseous refrigerant that has passed through the accumulator 8 is sucked into the compressor 1 and compressed.
  • An oil return pipe 9 is connected to the bottom side of the accumulator 8.
  • the oil return pipe 9 is a pipe that returns the refrigeration oil in the liquid refrigerant accumulated in the accumulator 8 to the compressor 1. At this time, not only refrigerator oil but also a small amount of liquid refrigerant is included.
  • an oil return adjuster 10 is disposed on the oil return pipe 9.
  • the oil return regulator 10 has an open / close valve, and opens or shuts off the oil return pipe 9 based on an instruction from the defrost control means 30, for example. When the oil return regulator 10 is opened, the refrigerating machine oil and a small amount of liquid refrigerant stored in the accumulator 8 are returned to the compressor 1 via the oil return pipe 9.
  • the refrigeration cycle apparatus 100 includes a hot gas bypass pipe 11, a flow rate regulator 12, and a defrost control unit 30.
  • the hot gas bypass pipe 11 is connected between the compressor 1 and the evaporator 7 and serves as a hot gas bypass flow path.
  • the hot gas bypass pipe 11 allows the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 to flow directly into the evaporator 7 without passing through the condenser 4a and the condenser 4b during the defrost operation.
  • the flow rate adjuster 12 adjusts the flow rate of the refrigerant flowing through the hot gas bypass pipe 11.
  • the flow rate regulator 12 includes, for example, a first on-off valve 12a and a second on-off valve 12b connected in parallel.
  • coolant which flows into the hot gas bypass piping 11 is adjusted with the combination of opening and closing of the 1st on-off valve 12a and the 2nd on-off valve 12b.
  • the flow rate of the refrigerant when the first on-off valve 12a is opened is larger than the flow rate that flows when the second on-off valve 12b is opened.
  • FIG. 1 illustrates the case where the flow rate regulator 12 includes the first on-off valve 12a and the second on-off valve 12b.
  • the flow rate regulator 12 may be composed of three or more on-off valves that can adjust the refrigerant flow rate in multiple stages.
  • you may comprise with one or more motor-driven valves which can adjust an opening degree continuously.
  • a needle valve 13 serving as a flow rate adjusting valve is connected in series with the first on-off valve 12a.
  • the needle valve 13 is disposed on the evaporator 7 side with respect to the first on-off valve 12a.
  • the needle valve 13 is adjusted in opening degree so that the refrigerant liquid does not return to the compressor 1.
  • the opening degree is set manually so that a predetermined flow rate of refrigerant flows during defrost control.
  • an opening degree can be adjusted so that it may become a refrigerant
  • the needle valve 13 may be provided at the rear stage of the first on-off valve 12a. Further, the needle valve 13 may be provided only at the subsequent stage of the second on-off valve 12b.
  • the defrost control means 30 controls the operation of the flow rate regulator 12.
  • the defrost control means 30 includes, for example, a control device 31, a storage device 32, and a timing device 33.
  • the control device 31 is a device that performs processing such as calculation and determination based on input data such as temperature, and controls equipment of the refrigeration cycle apparatus 100 such as the compressor 1 and the oil return regulator 10.
  • the storage device 32 is a device that stores data necessary for the control device 31 to perform processing.
  • the time measuring device 33 is a device such as a timer that performs time measurement necessary for the determination of the control device 31.
  • control device 31 is composed of, for example, a microcomputer having a control arithmetic processing device such as a CPU (Central Processing Unit).
  • storage device 32 has the data which made the process procedure which the control apparatus 31 performs a program.
  • the control arithmetic processing unit executes control based on the program data to realize control.
  • the present invention is not limited to this, and each device may be configured by a dedicated device (hardware).
  • the defrost control means 30 closes both the first on-off valve 12a and the second on-off valve 12b so that the refrigerant does not flow into the hot gas bypass pipe 11, for example, during the normal cooling operation.
  • the first on-off valve 12a and the second on-off valve 12b are controlled based on the flow rate of the refrigerant passed through the hot gas bypass pipe 11. For example, the first on-off valve 12a is opened to close the second on-off valve 12b, or both the first on-off valve 12a and the second on-off valve 12b are opened.
  • the defrost control means 30 adjusts the flow rate regulator 12 according to the discharge superheat degree SH of the compressor 1 and the suction pressure Pin of the compressor 1 detected by the refrigerant state detection means 20 during the hot gas defrost control. Then, control for adjusting the flow rate of the refrigerant flowing through the hot gas bypass pipe 11 is performed. Further, in the first embodiment, the oil return adjuster 10 is controlled to be closed when the defrost operation is started and to be opened after the standby set time.
  • the refrigerant state detection means 20 detects the discharge superheat degree SH of the refrigerant discharged from the compressor 1 and the suction pressure Pin of the compressor 1.
  • the refrigerant state detection means 20 includes a discharge temperature sensor 20a, a suction pressure sensor 20b, and a high pressure temperature sensor 20c.
  • the discharge temperature sensor 20a detects the discharge refrigerant temperature of the refrigerant discharged from the compressor 1.
  • the suction pressure sensor 20b detects the suction pressure Pin of the refrigerant sucked by the compressor 1.
  • the high-pressure temperature sensor 20 c detects the refrigerant temperature that has flowed out of the oil separator 2.
  • the defrost control means 30 also functions as part of the refrigerant state detection means.
  • the defrost control means 30 calculates the difference between the discharge refrigerant temperature detected by the discharge temperature sensor 20a and the high-pressure side temperature detected by the high-pressure temperature sensor 20c, and detects it as the discharge superheat degree SH.
  • the defrost control means 30 closes the oil return adjuster 10 until the standby set time from the start of the defrost.
  • the flow of the refrigerant in the refrigeration cycle apparatus 100 during the defrost operation will be described with reference to FIG.
  • the refrigerant discharged from the compressor 1 is separated into refrigerant and oil in the oil separator 2.
  • the gas refrigerant that has flowed out of the oil separator 2 branches via the check valve 3 into a refrigerant that flows to the condenser 4a and condenser 4b side and a refrigerant that flows to the hot gas bypass pipe 11 side.
  • the flow rate regulator 12 is closed during the normal cooling operation, so that the refrigerant does not pass through the hot gas bypass pipe 11.
  • the flow rate regulator 12 is opened.
  • at least one of the first on-off valve 12a and the second on-off valve 12b is opened. Details of the control will be described later.
  • the refrigerant that has flowed through the flow rate regulator 12 passes through the inside of the evaporator 7.
  • the frost is melted by heat exchange between the refrigerant and the frost adhered to the evaporator 7. Since the refrigerant in which the frost is melted in the evaporator 7 is partially condensed, it is gas-liquid separated by the accumulator 8. The gas refrigerant exiting the accumulator 8 is sucked into the compressor 1. On the other hand, the liquid refrigerant accumulated in the accumulator 8 is gradually returned to the compressor 1 by opening the oil return regulator 10.
  • the refrigerant that is more likely to evaporate first evaporates.
  • the high-pressure refrigerant evaporates earlier than the low-pressure refrigerant because the evaporation temperature is lower in the high-pressure refrigerant.
  • the composition of the refrigerant circulating in the refrigerant circuit becomes high-pressure refrigerant rich in which the high-pressure refrigerant is increased.
  • the discharge temperature of the refrigerant discharged from the compressor 1 is likely to rise.
  • the temperature difference between the frosted evaporator 7 and the refrigerant widens, and the amount of heat exchange between the refrigerant and frost in the evaporator 7 that becomes the amount of heat for defrosting increases.
  • FIG. 2 is a diagram illustrating a processing procedure related to control in the refrigeration cycle apparatus 100 according to Embodiment 1 of the present invention.
  • the defrost control means 30 performs hot gas defrost control processing during the defrost operation.
  • the hot gas defrost control performed by the defrost control means 30 of the refrigeration cycle apparatus 100 will be described with reference to FIGS. 1 and 2.
  • step ST1 when it is determined that the defrost operation is necessary, or when the defrost operation is performed periodically, the normal cooling operation is terminated (step ST1). Then, by the pump-down operation, the refrigerant recovery for enclosing the refrigerant remaining in the refrigerant circuit in a condenser or the like is performed for a predetermined time (step ST2). After the refrigerant recovery is completed, the pump down operation is stopped (step ST3). At this time, the defrost control means 30 closes the valve of the oil return regulator 10 and keeps it closed. Thereafter, the defrost operation is started (step ST10).
  • the defrost control means 30 opens the first on-off valve 12a of the flow rate regulator 12 (step ST11). A refrigerant having a first refrigerant flow rate flows through the hot gas bypass pipe 11.
  • the defrost control means 30 starts time measurement related to the oil return adjuster 10 in a process different from the following steps when the defrost operation is started (step ST11A). Then, it is determined whether or not a predetermined standby setting time has elapsed (step ST12A). If it is determined that the standby set time has elapsed, the valve of the oil return regulator 10 is opened (step ST13A).
  • the valve of the oil return regulator 10 is closed, and the liquid refrigerant having a high proportion of the low-pressure refrigerant is not returned to the compressor 1 but is stored in the accumulator 8, so that the compressor 1 In the refrigerant discharged from the refrigerant, the ratio of the high-pressure refrigerant can be increased, and the discharge temperature can be raised above the discharge temperature of the non-azeotropic refrigerant during normal operation.
  • the refrigerant state detection means 20 detects the discharge superheat degree SH and the suction pressure Pin of the compressor 1 (step ST12).
  • the discharge superheat degree SH is detected by the defrost control means 30 calculating the difference between the discharge refrigerant temperature detected by the discharge temperature sensor 20a and the high pressure side temperature detected by the high pressure temperature sensor 20c.
  • the suction pressure Pin 20 is detected by the suction pressure sensor 20b.
  • the defrost control means 30 determines whether or not the period during which the discharge superheat degree SH is larger than the set superheat degree SHref and the suction pressure Pin is smaller than the set pressure Pref is continued for a predetermined period t1 (step). ST13).
  • the set superheat degree SHref and the set pressure Pref are stored in advance in the storage device 32 of the defrost control means 30.
  • the predetermined period t1 is set to 10 seconds, for example.
  • the defrost control means 30 opens the first on-off valve 12a side of the flow regulator 12 and keeps the second on-off valve 12b closed until the condition in step ST13 is satisfied. To control.
  • step ST13 When the condition in step ST13 is satisfied, that is, in the case of YES in step ST13 in FIG. 2, the defrost control means 30 opens the second on-off valve 12b (step ST14). Then, the flow rate of the refrigerant flowing through the hot gas bypass pipe 11 becomes larger than when only the first on-off valve 12a is open. For this reason, the defrost time can be shortened.
  • step ST14 the discharge superheat degree SH and the suction pressure Pin of the compressor 1 are detected (step ST15). Then, the defrost control means 30 determines whether or not the period during which the discharge superheat degree SH is equal to or lower than the set superheat degree SHref or the period during which the suction pressure Pin is equal to or higher than the set pressure Pref continues for a predetermined period t2 ( Step ST16).
  • the predetermined period t2 is set to 3 seconds, for example.
  • the defrosting operation is performed in a state where both the first on-off valve 12a and the second on-off valve 12b of the flow rate regulator 12 are opened. That is, the flow is repeated along the route in the case of NO in step ST16.
  • step ST16 if the condition of step ST16 is satisfied, that is, if YES in step ST16, it is determined that there is a possibility of liquid return to the compressor 1, and the second opening / closing valve 12b is determined by the defrost control means 30. Is closed (step ST17). That is, a large amount of refrigerant used for defrost flows into the accumulator 8, and the liquid refrigerant may return to the compressor 1 beyond the allowable amount that allows the gas-liquid separation of the accumulator 8, so the second on-off valve 12b is closed. Reduce the amount of refrigerant used for defrosting. Thereafter, the defrosting operation is performed in a state where the first on-off valve 12a and the second on-off valve 12b are closed (steps ST12 and ST13).
  • the defrost operation is controlled by the flow from ST11 to ST17 by the defrost control means 30, and the flow is repeated until the defrost operation stop condition is reached.
  • the defrost operation stop condition is that the temperature at a predetermined location rises above a predetermined temperature. In the first embodiment, for example, when the outlet temperature of the evaporator 7 becomes 25 ° C. or higher, the defrost operation is stopped.
  • the defrost operation stop condition can be appropriately set according to the specifications of the refrigeration cycle apparatus 100.
  • the liquid return to the compressor 1 can be performed while shortening the period of the defrost operation. It can be surely prevented. That is, the amount of defrost heat increases as the amount of refrigerant flowing into the evaporator 7 increases and the refrigerant temperature increases. For this reason, the time which melts the frost adhering to the inside of the evaporator 7 also becomes short.
  • the pressure on the discharge side of the compressor 1 is detected rather than the pressure on the suction side of the compressor 1 as in the suction pressure sensor 20b shown in FIG.
  • the defrost control means 30 controls the opening and closing of the first on-off valve 12a and the second on-off valve 12b, and controls the amount of hot gas flowing into the evaporator 7.
  • the suction pressure Pin of the compressor 1 rises and the discharge pressure Pout of the compressor 1 does not increase
  • the first on-off valve 12a and the second on-off valve 12b are both opened from the first open / close state. Since only the valve 12a is not switched to an open state, the amount of liquid returned to the compressor 1 during defrosting increases.
  • the second on-off valve 12b is closed when a predetermined period has elapsed when the suction pressure Pin is equal to or higher than the set pressure Pref and the discharge superheat degree SH is equal to or lower than the set superheat degree SHref.
  • the predetermined period is set to 3 seconds, for example.
  • the reason why the amount of liquid return to the compressor 1 can be reduced by making the suction pressure Pin of the compressor 1 lower than the set pressure Pref is as follows.
  • the following three types of heat sources are used for condensing the hot gas refrigerant during the defrost operation. i) Sensible heat of the cooler housing (including local piping) ii) Sensible heat of frost iii) Latent heat of frost formation
  • i) to iii) can be further subdivided.
  • Sensible heat of -1 cooler housing (-40 ° C to 0 ° C) i) -2 Sensible heat of the cooler casing (0 ° C to + 20 ° C) ii) -1 Sensible heat of frost formation (-40 ° C to 0 ° C) ii) -2 Sensible heat of frost formation (0 ° C to + 20 ° C) iii) Latent heat of frosting
  • the temperature described above is an example in which defrosting is started from ⁇ 40 ° C. inside the cabinet, and defrosting is completed when the housing temperature is + 20 ° C.
  • the amount of heat used for condensing hot gas is only i) -1 and ii) -1, and the other amount of heat is not used for condensing hot gas. It is possible to reduce the amount of condensation.
  • the defrost control means. 30 starts the defrost operation, the oil return adjuster 10 is closed for the standby setting time, and the liquid refrigerant is positively accumulated in the accumulator 8, and when the standby setting time elapses, the oil return adjustment is performed.
  • FIG. FIG. 3 is a diagram showing the configuration of the refrigeration cycle apparatus 100 according to Embodiment 2 of the present invention.
  • devices having the same reference numerals as those in FIG. 1 perform the same operation as described in the first embodiment.
  • ⁇ System shutoff valve 40> In the refrigeration cycle apparatus 100 of FIG. 3, a system shutoff valve 40 is disposed on the inflow side of the condenser 4b. By opening and closing the system shut-off valve 40, it is possible to select the circulation or shut-off of the refrigerant to the condenser b.
  • FIG. 1 the case where the system shut-off valve 40 is provided only on the side of a part of the condenser 4b is illustrated, but the present invention is not limited to this.
  • System shutoff valves 40 may be provided in all the condensers 4a and 4b, and the defrost control means 30 may select the system shutoff valves 40 to be closed.
  • the defrost control means 30 opens the system shutoff valve 40 and allows the refrigerant to pass through the plurality of condensers 4a and 4b to perform the cooling operation. Further, during the defrost operation, the defrost control means 30 closes the system shutoff valve 40 in step ST11 of FIG. 2 described above to shut off the flow of the refrigerant to the condenser 4b.
  • the refrigeration cycle apparatus 100 according to the second embodiment is configured so that the hot gas bypass pipe is used during the defrost operation by arranging the system shutoff valve 40 on the inflow side of the condenser 4.
  • the defrost time can be shortened by causing the refrigerant to flow to 11 and blocking the refrigerant to flow to the condenser 4b to increase the condensation temperature as compared with the normal cooling operation.
  • Embodiment 3 FIG.
  • the defrost control means 30 stops all the condenser fans 5. Also good. By stopping the condenser fan 5 in the defrost operation, the amount of refrigerant flowing to the condenser 4 side can be reduced by reducing the amount of heat exchange in the condenser 4.
  • FIG. 4 is a diagram illustrating a processing procedure related to control in the refrigeration cycle apparatus 100 according to Embodiment 4 of the present invention.
  • the configuration of the equipment and the like of the refrigeration cycle apparatus 100 of the fourth embodiment is the same as that of FIG. 1 described in the first embodiment.
  • the defrost control means 30 can control the operating frequency of the compressor 1 during the defrost operation compared to the refrigeration cycle apparatus 100 according to the first to third embodiments. It is what I did. In the following, the description will be focused on differences from the first embodiment.
  • the defrost control means 30 can perform control to increase or decrease the operation frequency f of the compressor 1 during the defrost operation.
  • the defrost control means 30 opens only the first on-off valve 12a and operates the compressor 1 at a preset initial operation frequency f0. Then, the defrost control means 30 increases or decreases the operating frequency f based on the discharge superheat degree SH and the suction pressure Pin while keeping the refrigerant flow rate in the hot gas bypass pipe 11 constant.
  • the defrost control means 30 determines in the defrost control means 30 whether the discharge superheat degree SH is equal to or less than the set superheat degree SHref or the period during which the suction pressure Pin is equal to or less than the set pressure Pref continues for a predetermined period t3. (Step ST23).
  • the set superheat degree SHref and the set pressure Pref are stored in the defrost control means 30 in advance.
  • the compressor operating frequency is decreased (step ST24).
  • the predetermined period t3 is set to 3 seconds, for example.
  • the defrost control means 30 continues the defrost operation with the first on-off valve 12a side of the flow regulator 12 open and the second on-off valve 12b closed until the condition of step ST23 is satisfied. To control.
  • the defrost control means 30 determines whether or not the period during which the discharge superheat degree SH is greater than the set superheat degree SHref and the suction pressure Pin is greater than the set pressure Pref is continued for a predetermined period t4 (step ST25).
  • the predetermined period t4 is set to 10 seconds, for example. If the condition of step ST25 is not satisfied, that is, if NO in step ST25, the process is repeated from step ST21 again. If the condition of step ST25 is satisfied, that is, if YES in step ST25, the defrost control means 30 compares the operating frequency f of the compressor 1 with the maximum operating frequency fmax of the compressor 1 (step ST26).
  • step ST27 If the operating frequency f of the compressor 1 can be increased, that is, if YES in step ST26, the compressor 1 is controlled to increase by a predetermined frequency (step ST27). Then, the flow is repeated again from step ST21.
  • the operating frequency f of the compressor 1 is increased, the suction pressure Pin of the compressor 1 is decreased, and the discharge superheat degree SH is also decreased.
  • the operating frequency f of the compressor 1 is the maximum operating frequency fmax (NO in step ST26)
  • the speed is not increased and the second on-off valve 12b is opened (step ST28).
  • step ST30 the discharge superheat degree SH and the suction pressure Pin of the compressor 1 are detected (step ST29). Then, it is determined whether or not a period during which the discharge superheat degree SH is greater than the set superheat degree SHref and the suction pressure Pin is greater than the set pressure Pref continues for a predetermined period t5 (step ST30). In the fourth embodiment, t5 is set to 10 seconds, for example. If the above condition is satisfied, that is, if YES in step ST30, the operating frequency f of the compressor 1 is increased by a predetermined amount (step ST31). When the operating frequency f of the compressor 1 is increased, the suction pressure Pin of the compressor 1 is decreased, and the discharge superheat degree SH is also decreased. After the speed of the compressor 1 is increased, the flow from step ST28 is repeated. If the maximum operating frequency fmax has already been reached, the operation at the maximum operating frequency fmax is continued, and the flow from step ST28 is repeated.
  • step ST30 When the condition of step ST30 is not satisfied, that is, when NO in step ST30, the defrost control means 30 has a predetermined period during which the discharge superheat degree SH is equal to or lower than the set superheat degree SHref or the suction pressure Pin is equal to or lower than the set pressure Pref. It is determined whether or not t6 has been continued (step ST32). In the fourth embodiment, the predetermined period t6 is set to 3 seconds, for example. If NO in step ST32, it is determined that liquid return to the compressor 1 has not yet occurred, and the flow from ST28 is repeated again. If YES in step ST32, it is determined whether or not the operating frequency f of the compressor 1 is minimum (step ST33).
  • step ST34 When the operating frequency f of the compressor 1 does not reach the minimum operating frequency fmin, the compressor operating frequency is decreased (step ST34). The flow from step ST28 is repeated until the operating frequency f of the compressor 1 reaches the minimum operating frequency fmin. On the other hand, when the operating frequency f has reached the minimum operating frequency fmin, the second on-off valve 12b is closed (step ST35).
  • the refrigerant circulation amount is controlled by increasing or decreasing the operating frequency f of the compressor 1 in a state where both the first on-off valve 12a and the second on-off valve 12b are open (steps ST29 to ST35). And when the possibility of liquid return to the compressor 1 occurs, the hot gas defrost control is performed with the second on-off valve 12b closed and only the first on-off valve 12a opened again (step). ST21 to ST35).
  • the defrost operation is controlled by the flow from step ST21 to step ST35 by the defrost control means 30, and the flow is repeated until the defrost operation stop condition is reached.
  • the defrost operation stop condition is that the temperature at a predetermined location rises above a predetermined temperature.
  • the defrost operation stop condition can be appropriately set according to the specifications of the refrigeration cycle apparatus 100.
  • the compressor 1 is controlled by controlling both the flow rate of the refrigerant flowing through the hot gas bypass pipe 11 by the flow rate regulator 12 and the control of the refrigerant suction amount sucked into the compressor 1. Since the hot gas defrost can be performed with the maximum capacity within the range where the liquid return state does not occur, the liquid return to the compressor 1 can be reliably prevented while further shortening the defrost time.
  • the defrosting heat amount is lower than that of the refrigeration cycle apparatus 100 of the first embodiment or the like.
  • the defrost time can be further shortened.
  • FIG. 5 is a diagram showing a configuration of the refrigeration cycle apparatus 100 according to Embodiment 5 of the present invention.
  • the liquid level detection sensor 21 is a liquid level detection device that detects the position of the liquid refrigerant in the accumulator 8 in the height direction of the liquid level.
  • the defrost control means 30 controls the oil return adjuster 10 based on the position of the liquid level of the accumulator 8 detected by the liquid level detection sensor 21 during the defrost operation. It is.
  • the basic operation in the defrost operation is performed in the same procedure as the procedure shown in FIG. 2 described in the first embodiment.
  • the operation of the oil return adjuster 10 during the defrost operation is different.
  • the refrigeration cycle apparatus 100 of the fifth embodiment does not execute the processes of steps ST11A to ST13A described in the first embodiment, and performs the following processes.
  • FIG. 6 is a diagram illustrating a processing procedure related to the control of the oil return regulator 10 during the defrost operation according to the fifth embodiment of the present invention.
  • the process in FIG. 6 is performed by the defrost control means 30.
  • the valve of the oil return regulator 10 is closed.
  • hot gas defrost control in the defrost operation is started (step ST10), the position of the liquid level of the accumulator 8 is determined based on the detection of the liquid level detection sensor 21 (step ST41).
  • the detected liquid level position which is the position of the liquid level of the accumulator 8 related to the detection, is compared with a preset set liquid level position, and it is determined whether or not the set liquid level position ⁇ the detected liquid level position (step ST42). . If it is determined that the set liquid level position ⁇ the detected liquid level position, it is determined whether the preset liquid level position ⁇ the detected liquid level position has passed a preset valve opening set time (step ST43). Here, in the fifth embodiment, 10 seconds is set as the valve opening setting time. When the set liquid level position ⁇ the detected liquid level position continues for the valve opening set time, the valve of the oil return adjuster 10 is opened (step ST44). And during defrost operation, it returns to step ST41 and continues processing.
  • step ST42 determines whether or not the set liquid level position is less than the detected liquid level position. If it is determined that the detected liquid level position ⁇ the set liquid level position, it is determined whether or not the state of the detected liquid level ⁇ the set liquid level position has passed a preset valve closing set time (step ST46).
  • a preset valve closing set time 3 seconds is set as the valve closing setting time.
  • the defrost control means 30 judges the position of the liquid level in the liquid refrigerant accumulated in the accumulator 8, and controls the opening and closing of the valve of the oil return regulator 10 based on the detected liquid level position.
  • a low-pressure rich liquid refrigerant can be stored in 8. And since a refrigerant
  • coolant can be raised.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Defrosting Systems (AREA)
PCT/JP2017/021631 2017-06-12 2017-06-12 冷凍サイクル装置 WO2018229826A1 (ja)

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CN113074474A (zh) * 2021-04-12 2021-07-06 长虹美菱股份有限公司 一种中间集液储能蒸发器及其高效制冷系统

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CN114353360B (zh) * 2022-01-06 2024-02-23 青岛海尔空调电子有限公司 双压缩机制冷剂循环系统及其控制方法

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CN113074474A (zh) * 2021-04-12 2021-07-06 长虹美菱股份有限公司 一种中间集液储能蒸发器及其高效制冷系统
CN113074474B (zh) * 2021-04-12 2022-06-07 长虹美菱股份有限公司 一种中间集液储能蒸发器及其高效制冷系统

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