WO2017068649A1 - Système de pompe à chaleur - Google Patents

Système de pompe à chaleur Download PDF

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Publication number
WO2017068649A1
WO2017068649A1 PCT/JP2015/079571 JP2015079571W WO2017068649A1 WO 2017068649 A1 WO2017068649 A1 WO 2017068649A1 JP 2015079571 W JP2015079571 W JP 2015079571W WO 2017068649 A1 WO2017068649 A1 WO 2017068649A1
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Prior art keywords
heat exchanger
refrigerant
refrigerant flowing
expansion valve
outdoor heat
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PCT/JP2015/079571
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English (en)
Japanese (ja)
Inventor
千歳 田中
拓也 松田
航祐 田中
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三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2017546315A priority Critical patent/JPWO2017068649A1/ja
Priority to PCT/JP2015/079571 priority patent/WO2017068649A1/fr
Publication of WO2017068649A1 publication Critical patent/WO2017068649A1/fr

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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
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/89—Arrangement or mounting of control or safety devices

Definitions

  • the present invention relates to a heat pump system, and more particularly to a heat pump system including a bypass flow path configured such that at least a part of a refrigerant bypasses an outdoor heat exchanger.
  • condensation pressure of the refrigerant in the outdoor heat exchanger is excessively low during the cooling operation of the heat pump system, frost adheres to the indoor heat exchanger (evaporator) or excessive dehumidification occurs. Malfunctions can occur. Therefore, a technique for suppressing a decrease in the condensation pressure has been proposed.
  • Patent Document 1 discloses an air conditioner including a three-way valve that adjusts a ratio between a flow rate of refrigerant passing through a condenser and a flow rate of refrigerant bypassing the aggregator.
  • This air conditioner control means is used when a predetermined condition is satisfied (specifically, when the expansion valve is fully opened, when the compression ratio of the compressor is less than the allowable minimum compression ratio, or when the reheat amount of the reheater is a predetermined value).
  • the three-way valve is controlled in the direction of increasing the condensation pressure.
  • the refrigerant bypasses the condenser by changing the opening of the three-way valve as compared to when the predetermined condition is not satisfied.
  • the flow rate is set large. Thereby, the fall of a condensation pressure can be suppressed.
  • the flow rate of the refrigerant flowing through the condenser decreases as the flow rate of the refrigerant bypassing the condenser increases. For this reason, the amount of heat released from the refrigerant to the outside air in the condenser is reduced, so that the amount of decrease in the refrigerant temperature in the condenser can be reduced. If it does so, there exists a possibility that required supercooling degree cannot be ensured about the refrigerant
  • the present invention has been made to solve the above-described problems, and its purpose is to ensure a degree of supercooling of the refrigerant flowing into the expansion valve while suppressing a decrease in condensation pressure during cooling operation of the heat pump system. Is to provide new technology.
  • the same problem can occur during the heating operation of the heat pump system. That is, for example, when the heating operation is performed when the outside air temperature is high, the evaporation pressure of the refrigerant in the outdoor heat exchanger (evaporator) becomes higher than when the outside air temperature is low. That is, since the pressure of the refrigerant flowing out from the outdoor heat exchanger and flowing into the compressor increases, the compression ratio in the compressor decreases. In this case, by increasing the flow rate of the refrigerant that bypasses the evaporator by changing the opening of the three-way valve, an increase in the evaporation pressure can be suppressed.
  • the flow rate of the refrigerant flowing through the evaporator is reduced by the increase in the flow rate of the refrigerant bypassing the evaporator. For this reason, the amount of heat absorbed from the outside air to the refrigerant in the evaporator becomes small, so that the amount of increase in the refrigerant temperature in the evaporator can be small. If it does so, there exists a possibility that required superheat degree cannot be ensured about the refrigerant
  • Another object of the present invention is to provide a technology capable of ensuring the degree of superheat of the refrigerant flowing into the compressor while suppressing an increase in evaporation pressure during heating operation of the heat pump system.
  • a heat pump system includes a main circuit, a bypass flow path, a flow rate regulator, a branch flow path, a second expansion valve, and a sub heat exchanger.
  • the main circuit includes a compressor, an outdoor heat exchanger, a first expansion valve, and an indoor heat exchanger, and is configured to be able to circulate the refrigerant.
  • the bypass flow path is configured such that the refrigerant flowing through the main circuit bypasses the outdoor heat exchanger.
  • the flow rate adjuster is configured to be able to adjust the ratio of the flow rate of the refrigerant flowing through the outdoor heat exchanger to the flow rate of the refrigerant discharged from the compressor.
  • the branch flow path is connected between the outdoor heat exchanger and the first expansion valve, and is configured to be able to branch a part of the refrigerant flowing through the main circuit.
  • the second expansion valve is configured to be able to adjust the flow rate of the refrigerant flowing through the branch flow path.
  • the auxiliary heat exchanger exchanges heat between the refrigerant flowing through the branch flow path and the refrigerant flowing from the outdoor heat exchanger to the first expansion valve.
  • a heat pump system includes a main circuit, a bypass flow channel, a flow rate regulator, a branch flow channel, a second expansion valve, and a sub heat exchanger.
  • the main circuit includes a compressor, an outdoor heat exchanger, a first expansion valve, and an indoor heat exchanger, and is configured to be able to circulate the refrigerant.
  • the bypass flow path is configured such that the refrigerant flowing through the main circuit bypasses the outdoor heat exchanger.
  • the flow rate adjuster is configured to be able to adjust the ratio of the flow rate of the refrigerant flowing through the outdoor heat exchanger to the flow rate of the refrigerant discharged from the compressor.
  • the branch flow path is connected between the compressor and the indoor heat exchanger, and is configured to be able to branch a part of the refrigerant flowing through the main circuit.
  • the second expansion valve is configured to be able to adjust the flow rate of the refrigerant flowing through the branch flow path.
  • the auxiliary heat exchanger exchanges heat between the refrigerant flowing through the branch flow path and the refrigerant flowing from the outdoor heat exchanger to the compressor.
  • the ratio can be reduced by the flow rate regulator as compared with the case where the condensing pressure is within an appropriate range.
  • the flow rate of the refrigerant flowing through the branch flow path via the second expansion valve can be increased.
  • the amount of heat exchanged between the refrigerant flowing through the main circuit and the refrigerant decompressed by the second expansion valve is increased.
  • the temperature of the refrigerant flowing through the main circuit decreases, so that the degree of supercooling of the refrigerant flowing into the expansion valve can be ensured more reliably. Therefore, during the cooling operation of the heat pump system, it is possible to ensure the degree of supercooling while suppressing a decrease in the condensation pressure.
  • the degree of superheat of the refrigerant flowing into the compressor can be ensured while suppressing the increase in the evaporation pressure even during the heating operation of the heat pump system.
  • FIG. 1 is a block diagram schematically showing a configuration of a heat pump system according to Embodiment 1.
  • FIG. It is a figure which shows the structure of a three-way valve typically.
  • 3 is a flowchart for illustrating control of a three-way valve and a sub-expansion valve that is executed in the first embodiment.
  • FIG. 6 is a Ph diagram corresponding to the control of the three-way valve and the sub-expansion valve executed in the first embodiment.
  • It is a block diagram which shows schematically the structure of the heat pump system which concerns on the modification of Embodiment 1.
  • FIG. It is a block diagram which shows schematically the structure of the heat pump system which concerns on Embodiment 2.
  • FIG. 6 is a flowchart for illustrating control of a three-way valve and a sub-expansion valve that is executed in a second embodiment.
  • FIG. 1 is a block diagram schematically showing the configuration of the heat pump system according to the first embodiment.
  • heat pump system 100 includes a main circuit 110 and a control device 500.
  • Main circuit 110 includes compressor 10, outdoor heat exchanger 20, main expansion valve 30, indoor heat exchanger 40, and pipe 50.
  • the refrigerant flow during the cooling operation of the heat pump system 100 is indicated by an arrow REF.
  • the compressor 10 is a variable capacity compressor driven by, for example, an inverter (not shown).
  • the gas refrigerant that has been compressed by the compressor 10 to a high temperature and high pressure flows into the outdoor heat exchanger 20.
  • the outdoor heat exchanger 20 is a heat exchanger configured to include, for example, heat transfer tubes and heat radiating fins (not shown). During the cooling operation of the heat pump system 100, the outdoor heat exchanger 20 functions as a condenser. In the outdoor heat exchanger 20, the gas refrigerant condenses into a liquid refrigerant by dissipating heat to the outside air.
  • the main expansion valve (first expansion valve) 30 is a throttle valve whose opening degree can be controlled by, for example, a stepping motor (not shown).
  • the main expansion valve 30 is used for adjusting the flow rate of refrigerant (amount of refrigerant flowing per unit time).
  • the main expansion valve 30 decompresses the liquid refrigerant by expanding the high-pressure liquid refrigerant condensed by the outdoor heat exchanger 20. As a result, the refrigerant becomes a gas-liquid two-phase refrigerant and flows into the indoor heat exchanger 40.
  • the indoor heat exchanger 40 is a heat exchanger configured to include heat transfer tubes and radiating fins (not shown), like the outdoor heat exchanger 20.
  • the indoor heat exchanger 40 functions as an evaporator.
  • the air is cooled by the refrigerant.
  • the refrigerant is heated to change from a gas-liquid two-phase refrigerant to a low-pressure gas refrigerant. Thereafter, the gas refrigerant returns to the compressor 10 and is compressed again by the compressor 10 and discharged.
  • the main circuit 110 is formed by connecting the compressor 10, the outdoor heat exchanger 20, the main expansion valve 30, and the indoor heat exchanger 40 through the pipe 50 in this order.
  • the main circuit 110 may further include an accumulator (low pressure receiver), a receiver (high pressure receiver), or an oil separator (oil separator).
  • the heat pump system 100 further includes a bypass passage 120, a three-way valve 60, a branch passage 130, an internal heat exchanger 80, and a sub-expansion valve 70.
  • the heat pump system 100 further includes a pressure sensor 91 and temperature sensors 92 and 93.
  • the bypass channel 120 is connected between the upstream side and the downstream side of the outdoor heat exchanger 20.
  • the bypass passage 120 is configured such that the refrigerant flowing through the main circuit 110 bypasses the outdoor heat exchanger 20.
  • the three-way valve 60 is connected to a connection portion between the main circuit 110 and the bypass flow path 120.
  • the opening degree of the three-way valve 60 is changed by a control signal from the control device 500.
  • the configuration of the three-way valve 60 will be described in detail with reference to FIG.
  • the branch flow path 130 is connected between the outdoor heat exchanger 20 and the main expansion valve 30.
  • the branch flow path 130 is configured to be able to branch a part of the refrigerant flowing through the main circuit 110.
  • the secondary expansion valve (second expansion valve) 70 is provided in the branch flow path 130.
  • the sub-expansion valve 70 is a throttle valve whose opening degree can be controlled by, for example, a stepping motor (not shown). That is, the sub expansion valve 70 is configured to be able to adjust the flow rate of the refrigerant flowing through the branch flow path 130.
  • the internal heat exchanger (sub heat exchanger) 80 exchanges heat between the refrigerant flowing through the branch flow path 130 and the refrigerant flowing from the outdoor heat exchanger 20 to the main expansion valve 30.
  • the refrigerant that has undergone heat exchange in the internal heat exchanger 80 joins the refrigerant that flows from the indoor heat exchanger 40 to the compressor 10.
  • the pressure sensor 91 is provided on the discharge side of the compressor 10.
  • the pressure sensor 91 detects the pressure (discharge pressure) of the refrigerant discharged from the compressor 10 and outputs a signal indicating the detection result to the control device 500.
  • the discharge pressure of the compressor 10 is substantially equal to the condensation pressure Pc in the outdoor heat exchanger 20. Therefore, the condensation pressure Pc can be acquired by detecting the discharge pressure with the pressure sensor 91.
  • the temperature sensor 92 is provided on the discharge side of the compressor 10.
  • the temperature sensor 92 includes, for example, a thermistor, and detects the temperature (discharge temperature) of the refrigerant discharged from the compressor 10.
  • the temperature sensor 93 is provided on the outlet side of the internal heat exchanger 80.
  • the temperature sensor 93 includes, for example, a thermistor, and detects the condensation temperature of the refrigerant in the internal heat exchanger 80. Each sensor outputs a signal indicating the detection result to the control device 500.
  • control device 500 includes a CPU (Central Processing Unit), a memory such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and an input / output interface. Based on the detection signals from the above-described sensors, the control device 500 controls each device by causing the CPU to read a program stored in advance in a ROM or the like into the RAM and execute it.
  • CPU Central Processing Unit
  • RAM Random Access Memory
  • ROM Read Only Memory
  • control device 500 executes discharge temperature control for controlling the discharge temperature of the refrigerant to a target value by adjusting the opening of the main expansion valve 30. Moreover, the control apparatus 500 controls the three-way valve 60 and the sub expansion valve 70 based on the detection signal from each sensor. Details of control of the three-way valve 60 and the sub-expansion valve 70 by the control device 500 will be described later.
  • FIG. 2 is a diagram schematically showing the configuration of the three-way valve 60.
  • a three-way valve 60 includes an input port IN into which the refrigerant discharged from the compressor 10 flows, and an output port OUT1 through which the refrigerant flows out to the outdoor heat exchanger 20. And an output port OUT2 for allowing the refrigerant to flow out to the bypass channel 120, and a valve body 61.
  • the angle ⁇ of the valve body 61 can be changed within a range of 0 ° to 90 °, for example.
  • the ratio R of the flow rate of the refrigerant flowing out from the output port OUT1 with respect to the flow rate of the refrigerant flowing into the input port IN can be adjusted.
  • the ratio R is the ratio of the flow rate of the refrigerant flowing through the outdoor heat exchanger 20 to the flow rate of the refrigerant discharged from the compressor 10.
  • the ratio R is 1.
  • the ratio R becomes zero. In this way, the ratio R can be set by adjusting the angle ⁇ of the valve body 61 between the state shown in FIG. 2B and the state shown in FIG.
  • the three-way valve 60 corresponds to a “flow regulator” according to the present invention.
  • the configuration of the “flow regulator” according to the present invention is not limited to the three-way valve 60.
  • one two-way valve may be provided in each of the flow path between the compressor 10 and the outdoor heat exchanger 20 and the bypass flow path 120.
  • the ratio R can be set by adjusting the opening degree of each of the two two-way valves.
  • valve element 61 is set at a desired angle ⁇ without depending on the refrigerant temperature. Can be controlled. Therefore, the degree of freedom when setting the ratio R can be improved.
  • the condensation pressure saturated pressure when the refrigerant condenses in the outdoor heat exchanger 20
  • various problems may occur.
  • frost may adhere to the indoor heat exchanger 40 or excessive dehumidification may occur. Therefore, it is desirable to maintain the condensation pressure Pc within an appropriate range.
  • the angle ⁇ of the valve body 61 of the three-way valve 60 is adjusted as compared with the case where the condensation pressure Pc is greater than or equal to the reference value P1.
  • the ratio R can be reduced.
  • the flow rate of the refrigerant flowing through the outdoor heat exchanger 20 is decreased by the increase in the flow rate of the refrigerant bypassing the outdoor heat exchanger 20.
  • the amount of heat released from the refrigerant to the outside air in the outdoor heat exchanger 20 is reduced, and the amount of decrease in the refrigerant temperature in the outdoor heat exchanger 20 is reduced. If it does so, there exists a possibility that required supercooling degree (DELTA) Tc cannot be ensured about the refrigerant
  • DELTA required supercooling degree
  • the fact that the degree of supercooling ⁇ Tc cannot be secured means that the refrigerant flowing into the main expansion valve 30 is in a gas-liquid two-phase state.
  • the average density of the gas-liquid two-phase refrigerant is lower than the average density of the liquid refrigerant. Therefore, in order to realize a desired required cooling capacity for the gas-liquid two-phase refrigerant, it is required to increase the flow rate of the refrigerant flowing through the main expansion valve 30 as compared with the case of the liquid refrigerant. That is, it is necessary to increase the opening of the main expansion valve 30. However, generally, there is an upper limit for the opening of the expansion valve.
  • the opening degree of the main expansion valve 30 reaches the upper limit value, the flow rate of the refrigerant flowing through the main expansion valve 30 cannot be increased further. Therefore, in the case of a gas-liquid two-phase refrigerant, there is a possibility that a desired refrigerant capacity cannot be realized.
  • the opening degree of the sub expansion valve 70 is further controlled. More specifically, the refrigerant flowing through the internal heat exchanger 80 when the degree of supercooling ⁇ Tc of the refrigerant flowing into the main expansion valve 30 is lower than the reference value T2 compared to when the degree of supercooling ⁇ Tc is higher than the reference value T2.
  • the degree of opening of the secondary expansion valve 70 is controlled so that the flow rate of As a result, the amount of heat exchanged between the refrigerant flowing through the main circuit 110 and the refrigerant cooled by the pressure reduction at the sub expansion valve 70 increases.
  • the degree of supercooling of the refrigerant flowing into the main expansion valve 30 is more reliably ensured. can do.
  • FIG. 3 is a flowchart for explaining the control of the three-way valve 60 and the sub-expansion valve 70 executed in the first embodiment.
  • Each step (hereinafter abbreviated as S) of the flowchart shown in FIG. 3 and FIG. 7 described later is called from the main routine and executed every time a predetermined time elapses or a predetermined condition is satisfied.
  • control device 500 calculates condensing pressure Pc in outdoor heat exchanger 20.
  • the condensation pressure Pc can be calculated based on the discharge pressure detected by the pressure sensor 91.
  • the control device 500 determines whether or not the condensation pressure Pc is less than the reference value P1 (first reference value).
  • the reference value P1 is a value that does not cause the above-described problems such as frost adhesion in the indoor heat exchanger 40, and a value that does not cause an abnormality of the compressor 10 due to an excessively high compression ratio of the compressor 10. It is preferable that
  • the control device 500 adjusts the angle ⁇ of the valve body 61 of the three-way valve 60 in a direction in which the flow rate of the refrigerant toward the bypass flow path 120 increases.
  • the angle ⁇ is increased.
  • the ratio R of the flow rate of the refrigerant flowing through the outdoor heat exchanger 20 with respect to the flow rate of the refrigerant discharged from the compressor 10 decreases (S30).
  • the ratio of the refrigerant that reaches the downstream side of the outdoor heat exchanger 20 without passing through the outdoor heat exchanger 20 via the bypass flow path 120 increases, so that the condensation pressure Pc increases. Therefore, the fall of the condensation pressure Pc can be suppressed.
  • control device 500 calculates the degree of supercooling ⁇ Tc of the refrigerant flowing into main expansion valve 30.
  • the degree of supercooling ⁇ Tc can be calculated based on the refrigerant temperature detected by the temperature sensor 93 (the refrigerant temperature at the outlet side of the internal heat exchanger 80).
  • control device 500 determines whether or not the degree of supercooling ⁇ Tc is less than the reference value T2 (second reference value). A method for setting the reference value T2 will be described later.
  • control device 500 advances the process to S70.
  • the control device 500 maintains the opening degree of the sub-expansion valve 70 (or sets the opening degree of the sub-expansion valve 70), assuming that a sufficient degree of subcooling ⁇ Tc is secured for the refrigerant flowing into the main expansion valve 30. Adjust it small).
  • control device 500 advances the process to S60.
  • control device 500 sets the opening degree of sub expansion valve 70 to be larger than that in the case where degree of supercooling ⁇ Tc is equal to or greater than reference value T2.
  • the flow rate of the refrigerant flowing through the branch flow path 130 increases, so that in the internal heat exchanger 80, the refrigerant is exchanged between the refrigerant flowing through the main circuit 110 and the refrigerant cooled by the decompression at the sub expansion valve 70. The amount of heat to be increased.
  • the temperature of the refrigerant flowing through the main circuit 110 is lower than when the degree of supercooling ⁇ Tc is greater than or equal to the reference value T2. Therefore, the degree of supercooling ⁇ Tc of the refrigerant flowing into the main expansion valve 30 can be ensured more reliably.
  • the control device 500 When the condensing pressure Pc is equal to or higher than the reference value P1 in S20 (YES in S20), the control device 500 maintains the angle ⁇ of the valve body 61 of the three-way valve 60, or refrigerant that goes to the bypass flow path 120.
  • the angle ⁇ is adjusted in the direction in which the flow rate decreases (S80). In the example shown in FIG. 2, the angle ⁇ is maintained or decreased. Thereby, the ratio R is maintained or increased.
  • the process returns to the main routine.
  • the “state value” is not limited to this.
  • the “state value” according to the present invention may be the temperature of the refrigerant flowing through the outdoor heat exchanger 20, the discharge temperature of the refrigerant from the compressor 10, or the compression ratio of the refrigerant in the compressor 10.
  • FIG. 4 is a Ph diagram corresponding to the control of the three-way valve 60 and the sub-expansion valve 70 executed in the first embodiment.
  • the horizontal axis represents specific enthalpy h [unit: kJ / kg], and the vertical axis represents pressure P [unit: MPa].
  • point A indicates the state of a low-pressure gas refrigerant (superheated steam).
  • the process from the point A to the point B is an adiabatic compression process by the compressor 10.
  • Point B indicates a state in which the refrigerant is compressed by the compressor 10.
  • Point D shows a state where the refrigerant bypassing the outdoor heat exchanger 20 via the three-way valve 60 and the refrigerant condensed by the outdoor heat exchanger 20 are mixed.
  • Point E indicates a supercooled state obtained by condensing the refrigerant in the outdoor heat exchanger 20 and further cooling a part of the refrigerant by the internal heat exchanger 80.
  • the process from the point E to the point F shows the expansion process of the refrigerant by the main expansion valve 30.
  • the process from the point E to the point G shows the expansion process of the refrigerant by the sub expansion valve 70.
  • a process from the point E to the point G and a process from the point F to the point G indicate an evaporation process in the indoor heat exchanger 40.
  • the necessary supercooling degree ⁇ Tc is secured for the refrigerant flowing into the main expansion valve 30 while suppressing the decrease in the condensation pressure Pc. can do.
  • the compression ratio of the compressor 10 can also be lower than an appropriate value.
  • the compression ratio is less than the appropriate value, it is conceivable to increase the compression ratio by increasing the drive frequency of the compressor 10 as compared with the case where the compression ratio is equal to or more than the appropriate value.
  • the driving frequency of the compressor 10 increases, the refrigerant evaporation pressure Pe decreases.
  • the compressor is stopped. Thereafter, when the evaporation pressure recovers until it exceeds the reference value, the compressor is driven again. That is, the compressor may be repeatedly driven and stopped (such control is also referred to as “low pressure cut control”).
  • the compressor 10 is prevented from reaching a state where the low pressure cut control of the compressor 10 is executed. In other words, the operation of the compressor 10 can be stabilized.
  • the reference value T2 (see S50 in FIG. 3) set for the degree of supercooling ⁇ Tc of the refrigerant flowing into the main expansion valve 30 will be described.
  • the reference value T2 is set so that the supercooled state of the refrigerant flowing into the main expansion valve 30 is maintained even when the indoor heat exchanger 40 is provided at a position higher than the outdoor heat exchanger 20. It is preferable. The reason for this will be described below.
  • the indoor heat exchanger 40 is provided at a position lower than the outdoor heat exchanger 20, the refrigerant flow from the outdoor heat exchanger 20 toward the indoor heat exchanger 40 is a downward flow. Therefore, the pressure generated by the gravity applied to the liquid refrigerant is applied to the main expansion valve 30. Therefore, even if the pressure of the liquid refrigerant decreases due to expansion at the main expansion valve 30, boiling of the refrigerant is suppressed.
  • the refrigerant flow from the outdoor heat exchanger 20 toward the indoor heat exchanger 40 is an upward flow. Therefore, unlike the case where the refrigerant flow is a downward flow, pressure due to gravity is not applied to the main expansion valve 30. Therefore, when the pressure of the liquid refrigerant is reduced at the main expansion valve 30, the refrigerant is boiled under reduced pressure, and the refrigerant may be in a gas-liquid two-phase state. Then, the above-mentioned abnormal noise or vibration problem may occur. Therefore, it is preferable to set the reference value T2 so that the supercooled state of the refrigerant is maintained even after the pressure is reduced in the main expansion valve 30.
  • FIG. 5 is a block diagram schematically showing a configuration of a heat pump system according to a modification of the first embodiment.
  • the configurations of outdoor heat exchanger 20A, bypass flow path 120A, and three-way valve 60A correspond to the configurations in heat pump system 100 according to Embodiment 1 (see FIG. 1). Different.
  • connection part C1 is provided in the predetermined position along the flow path provided in the outdoor heat exchanger 20A.
  • the outdoor heat exchanger 20A is divided into two parts: a heat exchanger upstream of the connection part C1 and a heat exchanger downstream of the connection part C1.
  • the input port IN of the three-way valve 60A is connected to the connection portion C1 by a bypass flow path 120A.
  • a part of the refrigerant flowing through the outdoor heat exchanger 20 passes through only the upstream heat exchanger and flows out of the outdoor heat exchanger 20 through the connection portion C1.
  • the remaining refrigerant flows through both the upstream heat exchanger and the downstream heat exchanger.
  • the output port OUT1 of the three-way valve 60A is connected to the connection part C2 on the downstream side of the connection part C1 with respect to the flow path inside the outdoor heat exchanger 60 by the bypass flow path 120A.
  • the output port OUT2 of the three-way valve 60A is connected to the main circuit 110 on the downstream side of the outdoor heat exchanger 20A by a bypass passage 120A.
  • the configuration of heat pump system 100A other than outdoor heat exchanger 20A, bypass flow path 120A, and three-way valve 60A is the same as the corresponding configuration of heat pump system 100 according to Embodiment 1, and therefore detailed description will be repeated. Absent.
  • the opening degree of the three-way valve is adjusted by the angle of the valve body.
  • the structure which can change every 1 degree in the movable range whose angle of a valve body is 0 degree or more and 90 degrees or less is assumed.
  • the flow rate ratio that can be adjusted by the three-way valve (the ratio between the flow rate of the refrigerant flowing out from the first output port and the flow rate of the refrigerant flowing out from the second output port) can be adjusted only in 90 ways. . Therefore, when the flow rate of the refrigerant flowing into the input port of the three-way valve is relatively large, it is difficult to finely adjust the flow rate between the first output port and the second output port.
  • the outdoor heat exchanger 20 is not divided
  • FIG. Therefore, in Embodiment 1, the cost of the outdoor heat exchanger 20 can be reduced.
  • a throttle capillary tube that causes a pressure loss equivalent to that of the outdoor heat exchanger 20A may be provided in the bypass flow path 120A on the downstream side of the three-way valve 60A. Due to the pressure loss caused by the throttle, it is possible to prevent the refrigerant flow rate from rapidly increasing when the opening of the three-way valve 60A is increased from the closed state.
  • two two-way valves may be provided instead of the three-way valve 60A.
  • one is provided between the output port OUT1 of the three-way valve 60A in FIG. 5 and the connection C2.
  • the other is provided between the output port OUT2 of the three-way valve 60A and the downstream side of the main circuit 110 with respect to the outdoor heat exchanger 20A.
  • the two-way valve is generally suitable for fine adjustment of the flow rate because the adjustment range of the opening is smaller than that of the three-way valve.
  • FIG. 6 is a block diagram schematically showing the configuration of the heat pump system according to the second embodiment.
  • outdoor heat exchanger 20 functions as an evaporator
  • indoor heat exchanger 40 functions as a condenser.
  • the configuration of the branch flow path 130B, the sub expansion valve 70B, and the internal heat exchanger 80B is different from the corresponding configuration in the heat pump system 100 according to Embodiment 1 (see FIG. 1).
  • the heat pump system 100B is different from the heat pump system 100 shown in FIG. 1 in that a temperature sensor 94 is provided instead of the temperature sensor 92.
  • the branch flow path 130B is connected between the compressor 10 and the indoor heat exchanger 40.
  • the branch flow path 130 ⁇ / b> B is configured to be able to branch a part of the refrigerant flowing through the main circuit 110.
  • the sub expansion valve 70B is provided in the branch flow path 130B.
  • the internal heat exchanger 80B exchanges heat between the refrigerant flowing through the branch flow path 130B and the refrigerant flowing from the outdoor heat exchanger 20 to the compressor 10.
  • the refrigerant that has undergone heat exchange in the internal heat exchanger 80B joins the refrigerant that flows from the outdoor heat exchanger 20 to the compressor 10.
  • the temperature sensor 94 is provided in the indoor heat exchanger 40.
  • the temperature sensor 94 detects the evaporation temperature of the refrigerant in the indoor heat exchanger 40 and outputs a signal indicating the detection result to the control device 500.
  • structures other than the branch flow path 130B, the sub-expansion valve 70B, and the internal heat exchanger 80B of the heat pump system 100B are the same as the corresponding structures of the heat pump system 100 according to the first embodiment, a detailed description will be given. Do not repeat.
  • the evaporation pressure Pe of the refrigerant in the outdoor heat exchanger 20 can be higher than when the outside air temperature is low. That is, since the pressure of the refrigerant flowing out of the outdoor heat exchanger 20 and flowing into the compressor 10 becomes high, the pressure of the refrigerant sucked into the compressor 10 and the pressure of the refrigerant discharged from the compressor 10 The difference can be small. That is, the compression ratio in the compressor 10 may be lowered.
  • Embodiment 2 all or part of the refrigerant flowing to the outdoor heat exchanger 20 is bypassed through the bypass flow path 120.
  • the refrigerant sucked into the compressor 10 is a gas refrigerant (gas phase single-phase refrigerant).
  • the refrigerant that has passed through the main expansion valve 30 during the heating operation of the heat pump system 100B is a gas-liquid two-phase refrigerant. For this reason, the refrigerant from the main expansion valve 30 to the three-way valve 60 and further sucked into the compressor 10 may be in a gas-liquid two-phase state.
  • the opening of the sub expansion valve 70 is set larger than in the case where the refrigerant temperature is lower than the reference value T3.
  • the flow rate of the refrigerant flowing through the heat exchanger 80 is increased.
  • the amount of heat exchanged between the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 and the gas-liquid two-phase refrigerant from the main expansion valve 30 to the three-way valve 60 increases.
  • the refrigerant sucked into the compressor 10 can be completely gasified, so that an abnormality of the compressor 10 can be prevented.
  • FIG. 7 is a flowchart for explaining the control of the three-way valve 60 and the sub-expansion valve 70 executed in the second embodiment.
  • control device 500 calculates evaporation pressure Pe in outdoor heat exchanger 20.
  • the evaporation pressure Pe can be calculated, for example, by converting the evaporation temperature of the indoor heat exchanger 40 detected using the temperature sensor 94 into a saturation pressure.
  • the control device 500 determines whether or not the evaporation pressure Pe is equal to or higher than the reference value P3 (third reference value).
  • the control device 500 adjusts the angle ⁇ of the valve body 61 of the three-way valve 60 in the direction in which the flow rate of the refrigerant toward the bypass flow path 120 increases. Thereby, the ratio R of the flow rate of the refrigerant flowing through the outdoor heat exchanger 20 with respect to the flow rate of the refrigerant discharged from the compressor 10 decreases (S130).
  • control device 500 calculates the heating degree ⁇ Te of the refrigerant flowing into compressor 10.
  • the degree of heating ⁇ Te can be calculated based on, for example, the refrigerant temperature detected by the temperature sensor 93 (the refrigerant temperature at the outlet side of the internal heat exchanger 80).
  • control device 500 determines whether or not the degree of superheat ⁇ Te is less than the reference value T4 (fourth reference value).
  • control device 500 maintains the opening degree of sub-expansion valve 70B on the assumption that sufficient superheat degree ⁇ Te is secured for the refrigerant flowing into compressor 10. (Or adjust the opening of the sub-expansion valve 70B to be small) (S170).
  • control device 500 sets the opening degree of sub-expansion valve 70B to be larger than when superheat degree ⁇ Te is greater than or equal to reference value T4. (S160).
  • the flow rate of the refrigerant flowing through the branch flow path 130B is increased, so that the internal heat exchanger 80B and the high-temperature and high-pressure gas refrigerant discharged from the compressor 10 and the gas from the main expansion valve 30 to the three-way valve 60 are discharged.
  • the amount of heat exchanged with the liquid two-phase refrigerant increases.
  • the temperature of the refrigerant flowing through the main circuit 110 is higher than when the degree of superheat ⁇ Te is equal to or greater than the reference value T4. Therefore, the degree of superheat ⁇ Te of the refrigerant flowing into the compressor 10 can be ensured more reliably.
  • Embodiment 2 may combine Embodiment 2 and a modification. That is, also in Embodiment 2, it is possible to adopt a configuration in which only a part of the refrigerant can bypass the outdoor heat exchanger.
  • the heat pump system including only one indoor unit has been described.
  • the present invention is also applicable to a heat pump system including a plurality of indoor units (that is, a plurality of main expansion valves and a plurality of indoor heat exchangers).
  • An example of such a system is a multi air conditioning system for buildings.
  • the present invention can also be applied to a case where mixed operation of cooling and heating is performed in the cooling main operation of the multi-air conditioning system.
  • the difference between the heat absorption amount in the cooling indoor unit and the heat dissipation amount in the heating indoor unit becomes smaller, the heat dissipation amount in the outdoor heat exchanger becomes smaller. Therefore, in some cases, it is desirable to reduce the heat radiation amount in the outdoor heat exchanger as compared with the cooling operation of the system including only one indoor unit.
  • the present invention can be applied to such a case.
  • 100, 100A, 100B heat pump system 10 compressor, 20, 20A outdoor heat exchanger, 30 main expansion valve, 40 indoor heat exchanger, 50 piping, 60, 60A three-way valve, 61 valve body, 70 sub expansion valve, 80 , 80B internal heat exchanger, 91 pressure sensor, 92-94 temperature sensor, 110 main circuit, 120, 120A bypass flow path, 130, 130B branch flow path, 500 control device.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Air Conditioning Control Device (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Abstract

Dans la présente invention, un circuit principal (110) comprend un compresseur (10), un échangeur de chaleur extérieur (20), un détendeur principal (30) et un échangeur de chaleur intérieur (40), et est configuré de manière à permettre à un fluide frigorigène de circuler en le traversant. Un trajet d'écoulement de dérivation (120) est configuré de manière à amener le fluide frigorigène s'écoulant à travers le circuit principal (110) à contourner l'échangeur de chaleur extérieur (20). Une soupape à trois voies (60) est configurée de manière à être capable d'ajuster le rapport du débit du fluide frigorigène s'écoulant à travers l'échangeur de chaleur extérieur (20) sur le débit du fluide frigorigène évacué du compresseur (10). Un trajet d'écoulement de ramification (130) est raccordé entre l'échangeur de chaleur extérieur (20) et le détendeur principal (30) et est configuré de façon à être capable de ramifier partiellement le fluide frigorigène s'écoulant à travers le circuit principal (110). Un sous-détendeur (70) est configuré de manière à être capable d'ajuster le débit du fluide frigorigène s'écoulant à travers le trajet d'écoulement de ramification (130). Un échangeur de chaleur interne (80) effectue un échange de chaleur entre le fluide frigorigène s'écoulant à travers le trajet d'écoulement de ramification (130) et le fluide frigorigène s'écoulant de l'échangeur de chaleur extérieur (20) au détendeur principal (30).
PCT/JP2015/079571 2015-10-20 2015-10-20 Système de pompe à chaleur WO2017068649A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111383963A (zh) * 2018-12-26 2020-07-07 东京毅力科创株式会社 温度调整装置和温度调整装置的控制方法
WO2021131437A1 (fr) * 2019-12-26 2021-07-01 株式会社デンソー Dispositif à cycle de fluide frigorigène

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Publication number Priority date Publication date Assignee Title
JPH06265232A (ja) * 1993-03-11 1994-09-20 Mitsubishi Electric Corp 空気調和装置
JP2004271166A (ja) * 2003-02-20 2004-09-30 Mitsubishi Electric Corp 冷凍空調装置、冷凍空調装置の運転方法
JP2005300157A (ja) * 2005-07-08 2005-10-27 Mitsubishi Electric Corp 空気調和装置
JP2009198099A (ja) * 2008-02-22 2009-09-03 Mitsubishi Electric Corp 空気調和装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06265232A (ja) * 1993-03-11 1994-09-20 Mitsubishi Electric Corp 空気調和装置
JP2004271166A (ja) * 2003-02-20 2004-09-30 Mitsubishi Electric Corp 冷凍空調装置、冷凍空調装置の運転方法
JP2005300157A (ja) * 2005-07-08 2005-10-27 Mitsubishi Electric Corp 空気調和装置
JP2009198099A (ja) * 2008-02-22 2009-09-03 Mitsubishi Electric Corp 空気調和装置

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111383963A (zh) * 2018-12-26 2020-07-07 东京毅力科创株式会社 温度调整装置和温度调整装置的控制方法
WO2021131437A1 (fr) * 2019-12-26 2021-07-01 株式会社デンソー Dispositif à cycle de fluide frigorigène
JP2021105457A (ja) * 2019-12-26 2021-07-26 株式会社デンソー 冷凍サイクル装置
CN114793444A (zh) * 2019-12-26 2022-07-26 株式会社电装 制冷循环装置
JP7380199B2 (ja) 2019-12-26 2023-11-15 株式会社デンソー 冷凍サイクル装置
CN114793444B (zh) * 2019-12-26 2024-01-02 株式会社电装 制冷循环装置

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