JPWO2016207992A1 - Air conditioner - Google Patents

Abstract

The air conditioner includes a reference setting unit that sets, as a reference value, an index related to the liquid phase temperature in the refrigerant amount determination mode that is performed first, and an index and reference related to the liquid phase temperature in the second and subsequent refrigerant amount determination modes. A refrigerant amount determination unit that compares the value and determines whether or not the amount of refrigerant in the refrigerant circuit has decreased. The reference setting unit includes an index determination unit that determines whether or not an index related to the liquid phase temperature is greater than or equal to a set threshold, and when the index determination unit determines that the index related to the liquid phase temperature is greater than or equal to the set threshold, An index related to the liquidus temperature is stored in the storage unit as a reference value. On the other hand, when it is determined that the index related to the liquid phase temperature is less than the set threshold value, the index related to the liquid phase temperature in the changed operating condition is stored in the storage unit as a reference value.

Description

  The present invention relates to an air conditioner having a function of determining leakage of refrigerant filled in a refrigerant circuit.

  2. Description of the Related Art Conventionally, a heat pump type air conditioner is known in which an outdoor unit and an indoor unit are connected by piping, and a refrigerant flows between the outdoor unit and the indoor unit to perform a heating operation or a cooling operation. In this air conditioner, the refrigerant gas is compressed in the compressor on the outdoor unit side, cooled and liquefied in the outdoor heat exchanger, and sent to the indoor unit. The liquid refrigerant sent to the indoor unit expands and vaporizes in the expansion device, and the indoor air is cooled by the heat of vaporization of the refrigerant in the indoor heat exchanger.

  At this time, an abnormality may occur in the compression process of the compressor, and an abnormality may occur in which the refrigerant does not become high pressure even when compressed, and this abnormality is mainly caused by an insufficient amount of cooling gas due to refrigerant leakage. It has become. Therefore, in an air conditioner having a liquid reservoir in the refrigerant circuit, an air conditioner has been proposed that determines the suitability of the refrigerant amount in a refrigerant amount determination mode in which surplus refrigerant in the liquid reservoir is stored on the high pressure side (for example, Patent Documents). 1). In Patent Document 1, in the refrigerant amount determination mode, in the forced cooling operation in which the outdoor heat exchanger becomes a condenser, the suitability of the refrigerant amount is determined based on the degree of supercooling at the outlet of the outdoor heat exchanger. Is disclosed.

JP 2006-23072 A

  By the way, in the air conditioner, various configuration patterns such as a difference in connection configuration between the indoor unit and the outdoor unit, an extended pipe length, and a height difference are generated depending on an installation location or the like. Even in such a wide variety of patterns, the presence or absence of refrigerant leakage from the refrigerant circuit is judged from the temperature data detected from the air conditioner after equipment installation or maintenance, and the occurrence of refrigerant leakage occurs before a significant decline in air conditioning capacity occurs. It is required to grasp.

  The present invention has been made in order to solve the above-described problems, and is capable of creating a reference value used for accurately determining the suitability of the refrigerant amount under any connection conditions. The purpose is to provide a harmony machine.

  The air conditioner of the present invention controls a refrigerant circuit based on a refrigerant circuit having a condenser, a state detection unit that detects a refrigerant state in the refrigerant circuit, and a refrigerant state detected in the state detection unit. And a control device having a function of executing a refrigerant amount determination mode for controlling the operation of the refrigerant circuit when determining the suitability of the refrigerant amount in the refrigerant circuit. The operation control unit that controls the refrigerant circuit based on the operation conditions set in advance sometimes, and the refrigerant state detected by the state detection unit when the refrigerant amount determination mode is executed, is related to the liquidus temperature of the condenser An index calculation unit for calculating an index, a reference setting unit for setting an index related to the liquid phase temperature calculated by the index calculation unit as a reference value in the first refrigerant amount determination mode, and a reference set by the reference setting unit In the second and subsequent refrigerant amount determination modes, the index relating to the liquid phase temperature calculated in the index calculation unit and the reference value stored in the storage unit are compared with each other in the refrigerant circuit. A refrigerant amount determination unit that determines whether or not the refrigerant amount is decreasing, and the reference setting unit includes an index determination unit that determines whether or not an index related to the liquidus temperature is equal to or higher than a set threshold value, and an operating condition When the index determination unit determines that the index related to the liquid phase temperature is less than the set threshold value during operation, the refrigerant amount determination mode is set so that the suction superheat degree is increased until the index related to the liquid phase temperature becomes larger than the set threshold value. A condition change unit that changes the operating conditions of the liquid crystal and stores an index related to the liquid phase temperature that is equal to or higher than the set threshold as a reference value when it is determined that the index related to the liquid phase temperature is equal to or higher than the set threshold during operation according to the operating condition. Remember in the department, When it is determined that the index related to the liquid phase temperature is equal to or higher than the set threshold after the change of the inversion condition, the reference value is determined to be stored in the storage unit as the reference value related to the liquid phase temperature in the operating condition after the change. Part.

  According to the air conditioner of the present invention, in the first refrigerant amount determination mode, the reference value differs depending on whether the index related to the liquid phase temperature is equal to or higher than the set threshold value and the index related to the liquid phase temperature is less than the set threshold value. Therefore, it is possible to create a reference value used when accurately determining whether or not the refrigerant amount is appropriate under any connection condition.

It is a refrigerant circuit figure which shows Embodiment 1 of the air conditioner of this invention. It is a block diagram which shows an example of the control apparatus in the air conditioner of FIG. It is a graph which shows the state of the outdoor heat exchanger at the time of refrigerant | coolant amount determination mode in the air conditioner of FIG. 2 is a flowchart showing an example of setting of a reference value in a first refrigerant amount determination mode in the air conditioner of FIG. It is a refrigerant circuit figure which shows Embodiment 2 of the indoor unit of the air conditioner of this invention. It is a refrigerant circuit figure which shows Embodiment 3 of the indoor unit of the air conditioner of this invention.

Embodiment 1. FIG.
Hereinafter, preferred embodiments of the air conditioner of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram showing Embodiment 1 of an air conditioner of the present invention. The air conditioner 1 of FIG. 1 is an apparatus used for indoor cooling operation and heating operation by performing, for example, a vapor compression refrigeration cycle operation. The air conditioner 1 includes an outdoor unit 10, an indoor unit 20, and connection pipes 2 and 3 that connect the outdoor unit 10 and the indoor unit 20. The outdoor unit 10 and the indoor unit 20 are connected to the connection pipes 2 and 3 respectively. The refrigerant circuit 1 </ b> A connected by is configured. Examples of the refrigerant used in the air conditioner 1 include HFC refrigerants such as R410A, R407C, and R404A, HCFC refrigerants such as R22 and R134a, or natural refrigerants such as hydrocarbon and helium.

  The outdoor unit 10 includes a compressor 11, a flow path switching device 12, an outdoor heat exchanger 13, an outdoor blower 14, a first throttle device 15, a receiver 16, and a second throttle device 17. The compressor 11 compresses and discharges the refrigerant, and includes, for example, a positive displacement compressor whose operating capacity is variably driven by a motor (not shown) controlled by an inverter. In addition, although the case where one compressor 11 is installed in the outdoor unit 10 of FIG. 1 is illustrated, two or more compressors 11 are connected in parallel depending on the number of connected indoor units 20 or the like. May be.

  The flow path switching device 12 is composed of, for example, a four-way valve, and switches the direction of the refrigerant flow in the refrigerant circuit 1A. During the cooling operation, the flow path switching device 12 connects the discharge side of the compressor 11 and the outdoor heat exchanger 13, and connects the suction side of the compressor 11 and the indoor heat exchanger 21. On the other hand, during the cooling operation, the flow path switching device 12 connects the discharge side of the compressor 11 and the indoor heat exchanger 21, and connects the suction side of the compressor and the outdoor heat exchanger 13.

  The outdoor heat exchanger 13 is, for example, a cross-fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins. The outdoor heat exchanger 13 functions as a refrigerant condenser during the cooling operation, and functions as a refrigerant evaporator during the heating operation. One of the outdoor heat exchangers 13 is connected to the flow path switching device 12 and the other is connected to the connection pipe 2. In FIG. 1, the outdoor heat exchanger 13 is illustrated as being divided into a plurality of heat exchangers 13A and 13B, but may be composed of a single heat exchanger.

  The outdoor heat exchanger 13 is provided with an outdoor blower 14 that blows outside air, and heat is exchanged between the outdoor air and the refrigerant flowing through the outdoor heat exchanger 13. The outdoor blower 14 can change the flow rate of the air supplied to the outdoor heat exchanger 13, and includes a fan such as a propeller fan and a motor that drives the fan. In addition, although the outdoor heat exchanger 13 has illustrated about the case where it is the fin tube type heat exchanger used as the heat absorption object of the condensation heat | fever of a refrigerant | coolant, the indoor air blower 22 is a multi-tube heat exchanger or It consists of a plate heat exchanger, and the heat absorption target of the heat of condensation of the refrigerant may be water, a heat medium, brine or the like, and the supply device for the heat absorption target may be a pump or the like.

  The first expansion device 15 includes, for example, an electronic expansion valve and the like, and decompresses and expands the high-temperature and high-pressure liquid condensed by the condenser to form a low-temperature and low-pressure refrigerant. When the first expansion device 15 receives the first pressure reduction and expands, the liquid state is changed.

  The receiver 16 stores an excess refrigerant amount, is provided on the downstream side of the first expansion device 15, and is connected to the indoor unit 20 via the connection pipe 3. Note that, since there is a difference in the amount of refrigerant required between the cooling operation and the heating operation, surplus refrigerant generated in the normal operation is stored in the receiver 16. Moreover, since the excess refrigerant | coolant is stored in the receiver 16, the addition of the refrigerant | coolant in the installation place of the air conditioner 1 becomes unnecessary.

  The second expansion device 17 performs decompression of the refrigerant flowing in the refrigerant circuit 1 </ b> A or adjustment of the flow rate of the refrigerant. One of the second expansion devices 17 is connected to the indoor heat exchanger 21, and the other is connected to the receiver 16 via the connection pipe 3. It is connected to the.

  The indoor unit 20 includes an indoor heat exchanger 21 and an indoor blower 22. The indoor heat exchanger 21 is, for example, a cross-fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins. The indoor heat exchanger 21 functions as a condenser during the cooling operation, and functions as an evaporator during the heating operation. The indoor heat exchanger 21 is provided with an indoor blower 22 for blowing outside air, and heat is exchanged between the outdoor air and the refrigerant flowing through the indoor heat exchanger 21. The indoor blower 22 can change the flow rate of air supplied to the indoor heat exchanger 21, and includes a fan such as a centrifugal fan or a multiblade fan, and a motor that drives the fan. In addition, although the indoor heat exchanger 21 has illustrated about the case where the thing which becomes the heat absorption object of the heat of condensation of a refrigerant | coolant is a fin tube type heat exchanger, the indoor air blower 22 is a multitubular heat exchanger. Or it consists of a plate type heat exchanger, the heat absorption object of the condensation heat | fever of a refrigerant | coolant may be water, a heat medium, a brine, etc., and the supply apparatus of heat absorption object may be a pump.

  The air conditioner 1 includes a control device 40 that controls the operation of the refrigerant circuit 1A. The control device 40 performs a normal operation mode in which the cooling operation and the heating operation are performed according to the air conditioning load, and a refrigerant amount determination mode that is an operation mode for determining the refrigerant amount in the refrigerant circuit 1A. The refrigerant flow in each operation mode will be described below.

  An example of the operation of the air conditioner 1 during the cooling operation will be described with reference to FIG. In the cooling operation, the refrigerant flow path in the flow path switching device 12 is switched so that the outdoor heat exchanger 13 becomes a condenser and the indoor heat exchanger 21 becomes an evaporator. First, a low-temperature / low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature / high-pressure gas refrigerant. After that, the high-temperature and high-pressure gas refrigerant passes through the flow path switching device 12 and exchanges heat with the outdoor air blown by the outdoor blower 14 in the outdoor heat exchanger 13 acting as a condenser to dissipate heat to the outdoor air. To be cooled.

  Then, the refrigerant is depressurized in the first expansion device 15 disposed at the outlet of the outdoor heat exchanger 13, and becomes a refrigerant in a gas-liquid two-phase state with an intermediate temperature and an intermediate pressure. The medium-temperature / medium-pressure refrigerant flows into the receiver 16, is depressurized by the second expansion device 17, becomes a low-temperature / low-pressure refrigerant, and flows from the outdoor unit 10 into the indoor unit 20 through the connection pipe 3. The refrigerant that has flowed into the indoor unit 20 exchanges heat with the indoor air blown by the indoor blower 22 in the indoor heat exchanger 21 that operates as an evaporator, and removes heat from the indoor air, thereby cooling the room. The refrigerant flowing out of the indoor unit 20 flows into the outdoor unit 10 again, passes through the flow path switching device 12, becomes a low-temperature / low-pressure refrigerant, and is sucked into the compressor 11.

  Next, an example of the operation of the air conditioner 1 during heating operation will be described with reference to FIG. During the heating operation, the refrigerant flow path in the flow path switching device 12 is switched so that the outdoor heat exchanger 13 becomes an evaporator and the indoor heat exchanger 21 becomes a condenser. First, the refrigerant discharged from the compressor 11 flows to the indoor unit 20 through the flow path switching device 12, and the indoor heat exchanger 21 heats the indoor air by radiating heat to the indoor air.

  Thereafter, the refrigerant that has flowed out of the indoor heat exchanger 21 flows into the outdoor unit 10 through the connection pipe 3, is reduced to an intermediate pressure in the second expansion device 17, and is stored in the receiver 16. The refrigerant flowing out from the receiver 16 is decompressed to a low pressure by the first expansion device 15 and flows into the outdoor heat exchanger 13. In the outdoor heat exchanger 13, the refrigerant exchanges heat with outdoor air, and then becomes a low-temperature / low-pressure refrigerant and is sucked into the compressor 11.

  Next, an example of the operation in the refrigerant amount determination mode will be described with reference to FIG. The refrigerant amount determination mode is an operation mode in which refrigerant including surplus refrigerant is collected on the high pressure side of the refrigerant circuit 1A. In the refrigerant amount determination mode, control may be performed so that the refrigerant flows through a cooling flow path in which the outdoor heat exchanger 13 becomes a condenser, or a heating flow path in which the indoor heat exchanger 21 becomes a condenser. The refrigerant may be controlled so as to flow. In the following description, the case where the refrigerant flows in the refrigerant circuit 1A in the cooling flow path in which the outdoor heat exchanger 13 is a condenser will be exemplified.

  In the refrigerant quantity determination mode, the control device 40 performs control so that the refrigerant quantity sucked or discharged in the compressor 11 is stabilized and the refrigerant quantity in the outdoor heat exchanger 13 is made constant. Specifically, the control device 40 controls the rotation speed of the compressor 11 so as to be constant at a predetermined value, and sets the suction superheat degree SHs at the suction position of the compressor 11 so as to be constant at a predetermined value. One diaphragm device 15 is controlled. At this time, the second expansion device 17 is fully opened or substantially fully opened. Thereby, the refrigerant | coolant amount suck | inhaled and discharged by the compressor 11 is stabilized, and the refrigerant | coolant amount in the outdoor heat exchanger 13 which is a condenser becomes fixed.

  When each of the above operation modes is executed, the control device 40 controls the operation of the refrigerant circuit 1A based on information detected by the state detection unit 30. That is, the control device 40 includes the compressor 11, the flow path switching device 12, and the first throttling device that are components of the refrigerant circuit 1A so that the state quantity detected by the state detection unit 30 falls within the desired control target range. 15, the 2nd aperture device 17, the outdoor air blower 14, the indoor air blower 22, etc. are controlled.

  The state detection unit 30 detects the state of the refrigerant in the refrigerant circuit 1A. Specifically, the state detection unit 30 is provided on the discharge side of the compressor 11, and includes a discharge sensor 31 that detects the discharge temperature and discharge pressure of the refrigerant discharged from the compressor 11, and the outdoor air suction of the outdoor unit 10. An outdoor temperature sensor 32 that detects the outdoor temperature of the outdoor air, a condensation temperature sensor 33 that detects the condensation temperature of the outdoor heat exchanger 13 in the heating channel, and the outdoor heat exchanger 13 in the heating channel. And a liquid-side temperature sensor 34 that detects the temperature of the liquid refrigerant. Furthermore, the state detection unit 30 includes an inlet temperature sensor 35 that detects the evaporator inlet temperature of the refrigerant flowing into the indoor heat exchanger 21 in the heating channel, and an evaporation temperature sensor 36 that detects the evaporation temperature in the indoor heat exchanger 21. An outlet temperature sensor 37 for detecting the evaporator outlet temperature of the refrigerant flowing out to the indoor heat exchanger 21 in the heating channel, an indoor temperature sensor 38 for detecting the indoor air temperature in the indoor heat exchanger 21, and the compressor 11 And a suction sensor 39 that detects a suction temperature and a suction pressure of the refrigerant sucked into the compressor 11.

  FIG. 2 is a block diagram showing an example of a control device in the air conditioner of FIG. The configuration of the control device 40 shown in FIG. 2 is constructed by executing a program on hardware such as a microcomputer. 2 illustrates the case where the control device 40 is provided on the outdoor unit 10 side, the control device 40 may be provided on the indoor unit 20 side, or the outdoor unit 10 and the indoor unit 20 such as a centralized controller. It may be provided as a separate body. 2 includes an operation control unit 41, an index calculation unit 42, a refrigerant amount determination unit 43, a storage unit 44, and a reference setting unit 45.

  The operation control unit 41 controls the refrigerant circuit 1A on the basis of preset operation conditions in the refrigerant amount determination mode. In the operation control unit 41, for example, a set suction superheat degree SHsref is set as a preset operation condition. The operation control unit 41 controls the refrigerant circuit 1A so that the suction superheat degree SHs at the refrigerant suction position in the compressor 11 becomes the set suction superheat degree SHsref. Then, as described above, the operation control unit 41 controls the rotation speed of the compressor 11 to be constant at a predetermined value, and the suction superheat degree SHs at the suction position of the compressor 11 is constant at the set suction superheat degree SHsref. The first diaphragm device 15 is controlled so that

  It is desirable to control the refrigerant circuit 1A so that the set suction superheat degree SHsref is about 10 [K]. This is because when the suction superheat degree SHs increases, the low-pressure side refrigerant moves to the high-pressure side, and the supercooling degree SC in the outdoor heat exchanger 13 increases. In addition, the air volume of the outdoor blower 14 is desirably controlled so that the difference between the outside air temperature and the condensation temperature is constant.

  Further, the operation control unit 41 is discharged from the compressor 11 to the operation control unit 41 in order to prevent the occurrence of problems relating to the safety of the entire apparatus due to an excessive increase in the high-pressure side pressure of the refrigerant circulating in the refrigerant circuit 1A. The set pressure value (discharge temperature limit value or high pressure limit pressure value) of the refrigerant is set. And when the discharge temperature of the refrigerant | coolant discharged from the compressor 11 is larger than a discharge temperature limit value, it has the function to perform the high voltage | pressure protection control which restrict | limits operation | movement of the compressor 11. For example, the operation control unit 41 performs high-pressure protection control such as lowering or stopping the frequency of the compressor 11 in order to lower the refrigerant discharge temperature from the compressor 11.

  The index calculation unit 42 determines the liquid phase temperature of the outdoor heat exchanger 13 or the indoor heat exchanger 21 that is a condenser from the state of the refrigerant detected by the state detection unit 30 when the refrigerant amount determination mode is executed. It calculates the index related to In addition, it illustrates about the case where the outdoor heat exchanger 13 is a condenser.

  FIG. 3 is a graph showing the state of the outdoor heat exchanger in the refrigerant amount determination mode in the air conditioner of FIG. The index calculation unit 42 calculates the liquid phase temperature efficiency as an index indicating the state of the liquid phase using the following formula (1).

[Equation 1]
Liquid temperature efficiency = SC / dTc (1)

  In the above formula (1), SC represents the degree of supercooling [K] of the outdoor heat exchanger 13 (= condensation temperature−condenser outlet temperature), and dTc represents the condensation temperature [° C.] − Outside air temperature [° C.]. Further, the condensing temperature, the condenser outlet temperature, and the outside air temperature are detected by the state detection unit 30. The index calculation unit 42 calculates the liquid temperature efficiency as an index related to the liquid phase temperature using the condensation temperature, the condenser outlet temperature, and the outside air temperature detected by the state detection unit 30.

  In addition, the index calculation unit 42 calculates the suction superheat degree SHs at the suction position of the compressor 11 and the discharge superheat degree SHd at the discharge position. Various known methods can be used to calculate the suction superheat degree SHs and the discharge superheat degree SHd. For example, the index calculation unit 42 subtracts the suction pressure saturation temperature corresponding to the discharge pressure from the refrigerant suction temperature detected by the suction sensor 39 of the compressor 11 to calculate the suction superheat degree SHs. The index calculation unit 42 subtracts the discharge pressure saturation temperature corresponding to the discharge pressure from the refrigerant discharge temperature detected by the discharge sensor 31 to calculate the discharge superheat degree SHd. Therefore, the operation control unit 41 controls the first expansion device 15 so that the suction superheat degree SHs calculated by the index calculation unit 42 becomes constant at the set suction superheat degree SHsref.

  In the second and subsequent refrigerant amount determination modes, the refrigerant amount determination unit 43 compares the index related to the liquid phase temperature calculated by the index calculation unit 42 with the reference value RV stored in the storage unit 44, and generates a refrigerant circuit. It is determined whether or not the amount of refrigerant in 1A is decreasing. The index related to the liquid phase temperature is, for example, the liquid temperature efficiency calculated by the above equation (1), and the refrigerant amount determination unit 43 is the liquid temperature after a predetermined time has elapsed since the operation in the refrigerant amount determination mode was started. The efficiency is compared with the reference value RV, and it is determined whether or not the refrigerant amount has decreased compared to the first refrigerant amount determination mode.

  The reference setting unit 45 sets an index related to the liquid phase temperature calculated by the index calculation unit 42 as the reference value RV in the first refrigerant amount determination mode. The reference value RV set in the reference setting unit 45 is stored in the storage unit 44. Here, the reference setting unit 45 sets a different reference value RV according to the state of the refrigerant circuit 1A in the first refrigerant amount determination mode, and includes an index determination unit 45a, a condition change unit 45b, and a reference value. A determination unit 45c is provided.

  The index determination unit 45a determines whether or not the index related to the liquid phase temperature is equal to or greater than the set threshold value Aref. When the above-described index related to the liquid phase temperature is the liquid temperature efficiency in the condenser (outdoor heat exchanger 13), the setting threshold Aref is set to a value between 0.3 and 0.9. In order to obtain sufficient detection accuracy, the setting threshold value Aref is more preferably a value having a liquid temperature efficiency of 0.5 or more. When the liquid temperature efficiency is equal to or higher than the set threshold Aref, it means that the refrigerant is in a stable state in the refrigerant amount determination mode. When the liquid temperature efficiency is less than the set threshold Aref (or 0), in the refrigerant amount determination mode. It means that the refrigerant is in an unstable state.

  When the index determining unit 45a determines that the index related to the liquid phase temperature is less than the set threshold Aref, the condition changing unit 45b increases the suction superheat degree SHs until the index related to the liquid phase temperature becomes equal to or higher than the set threshold Aref. Thus, the operation condition in the operation control unit 41 is changed. Specifically, the condition changing unit 45b changes the operating condition so that the set suction superheat degree SHsref, which is a control target value, is increased by a predetermined amount. Then, the operation control unit 41 performs control to reduce the opening degree of the first expansion device 15 so that the intake superheat degree SHs becomes the changed set intake superheat degree SHsref. Then, the condition changing unit 45b changes the operating condition until the index determining unit 45a determines that the liquid phase temperature efficiency is equal to or higher than the set threshold value Aref.

  Here, when the connection pipe length is long within the range of the specified connection pipe length (long connection), the volume in the refrigerant circuit 1A is increased by the volume of the connection pipes 2 and 3. In particular, in a chargeless air conditioner shipped with a specified amount of refrigerant filled so that refrigerant replenishment is not required after installation, the connection pipe length may be long. In this case, when the refrigerant amount determination mode is performed in the heating operation, liquid refrigerant accumulates in the volume of the connection pipe on the high pressure side. As a result, the degree of supercooling SC in the outdoor heat exchanger 13 is less likely to occur, and the liquidus temperature efficiency becomes less than the set threshold Aref. Therefore, for example, when the set suction superheat degree SHsref in the compressor 11 is 10 [K], the refrigerant on the low pressure side is moved to the high pressure side by changing it higher by a predetermined amount (for example, 3 to 5 [K]). Thus, control is performed so that the value of the liquid phase temperature efficiency is equal to or higher than the set threshold value Aref.

  The reference value determination unit 45c determines a different reference value RV depending on whether the index related to the liquidus temperature is equal to or higher than the set threshold Aref or less than the set threshold Aref, and stores the reference value RV in the storage unit 44. That is, when it is determined that the index related to the liquid phase temperature is equal to or higher than the set threshold value Aref under the preset operating condition, the reference value determining unit 45c sets the index related to the liquid phase temperature equal to or higher than the set threshold value Aref. The reference value RV is stored in the storage unit 44. In the second and subsequent refrigerant amount determination modes, the refrigerant amount determination unit 43 determines whether or not the index related to the liquid phase temperature is equal to or higher than the reference value RV stored in the storage unit 44, and the liquid phase temperature efficiency. Is less than the reference value RV, it is determined that the refrigerant is decreasing.

  On the other hand, when it is determined that the index related to the liquid phase temperature is equal to or higher than the set threshold Aref after the operating condition is changed, the reference value determining unit 45c displays the index related to the liquid phase temperature under the changed operating condition. The reference value RV is stored in the storage unit 44.

  At this time, the reference value determination unit 45c stores the changed operating condition in the storage unit 44 together with the reference value RV. The changed operating condition stored in the storage unit 44 is, for example, the reference discharge superheat degree SHdref when the liquid phase temperature efficiency is equal to or higher than the set threshold Aref. When the operation condition is stored in the storage unit 44 together with the reference value RV in the storage unit 44, the operation control unit 41 stores the discharge superheat degree SHd of the refrigerant discharged from the compressor 11 in the storage unit 44. The refrigerant circuit 1A is controlled so that the reference discharge superheat degree SHdref is obtained. In the state where the discharge superheat degree SHd becomes the reference discharge superheat degree SHdref, when the liquid temperature efficiency is less than the reference value RV, the refrigerant amount determination unit 43 determines that the refrigerant amount has decreased from the reference value RV.

  When determining the refrigerant amount for the second and subsequent times based on the discharge superheat degree SHd, the outside air temperature may be corrected for the liquid temperature efficiency. Further, the case where the operation condition preset in the operation control unit 41 is the set suction superheat degree SHsref and the changed operation condition stored in the storage unit 44 is the set discharge superheat degree SHdref is illustrated. The changed set suction superheat degree SHsref in which the index related to the liquid phase temperature becomes equal to or higher than the set threshold value Aref may be stored as the changed operating condition.

  Further, the reference setting unit 45 has a function of storing the fact that the high pressure protection control is executed when the operation control unit 41 performs the high pressure protection control in the first refrigerant amount determination mode. That is, when high-pressure protection is activated during operation in the refrigerant amount determination mode, it means that there is not enough refrigerant to be collected on the high-pressure side of the refrigerant circuit 1A in the operation range of the normal operation mode. ing.

  In particular, in a chargeless type air conditioner shipped in a state where a specified amount of refrigerant is filled, when the length of the connection pipes 2 and 3 is within the range of the specified connection pipe length, the refrigerant is usually used in cooling operation. By performing the amount determination mode, the above-described problems such as high-pressure protection control and increase in discharge temperature do not occur. However, when the refrigerant amount determination mode is performed in the heating flow path in which the indoor heat exchanger 21 is a condenser, the outdoor heat exchange is performed when the lengths of the connection pipes 2 and 3 are shorter than the specified connection pipe length range. In some cases, the high-pressure protection control is performed in order to move the refrigerant to the indoor heat exchanger 21 having a smaller capacity than the condenser 13.

  Therefore, when the high pressure protection control is activated, the reference setting unit 45 activates the high pressure protection control in order to determine that the refrigerant amount determination unit 43 does not have a shortage of refrigerant due to refrigerant leakage or the like. Is stored in the storage unit 44. Then, in the second and subsequent refrigerant amount determination modes, the refrigerant amount determination unit 43 determines that the refrigerant amount has not decreased as a result that matches the state stored in the storage unit 44 when the high pressure protection control is activated. To do.

  When the outside air temperature is sufficiently low (for example, 0 ° C. or lower) or sufficiently high (for example, 40 ° C. or higher), the refrigerant amount determination mode and the determination operation may not be performed. Similarly, when the indoor environmental temperature is sufficiently low (for example, 10 ° C. or less), the determination may not be performed. Furthermore, when the volume of the outdoor heat exchanger 13 and the indoor heat exchanger 21 is significantly different depending on the combination of the outdoor unit 10 and the indoor unit 20, the determination may not be performed.

  FIG. 4 is a flowchart showing an example of setting of the reference value in the first refrigerant amount determination mode in the air conditioner of FIG. 1, and an operation example at the time of setting the reference value will be described with reference to FIGS. . When the refrigerant amount determination mode is first set at the time of stationary or the like (step ST1), the refrigerant circuit 1A is operated so that the refrigerant state circulating in the refrigerant circuit is stabilized in the operation control unit 41. Specifically, the first throttle device 15 is controlled so that the rotation speed of the compressor 11 is constant, and the suction superheat degree SHs at the suction position of the compressor 11 is constant at the set suction superheat degree SHsref. Is done.

  At this time, it is determined whether or not the high pressure protection control by the operation control unit 41 has been activated (step ST2). When it is determined that the high-pressure protection control has been activated (YES in step ST2), an index related to the liquid phase temperature (liquid phase temperature efficiency) is stored in the storage unit 44 as the reference value RV for refrigerant leakage determination (step ST3). On the other hand, when the high-pressure protection control is not activated (NO in step ST2), it is determined whether or not the index related to the liquidus temperature is equal to or higher than the set threshold Aref after a predetermined time has elapsed since the start of operation. Thereby, it is determined whether or not the state of the refrigerant in each part of the refrigerant circuit 1A is stable (step ST4). When the liquid phase temperature efficiency is equal to or higher than the set threshold Aref, it is determined that the state of the refrigerant is stable (YES in step ST4), and an index related to the liquid phase temperature is stored in the storage unit 44 as the reference value RV. (Step ST5).

  On the other hand, when it is determined that the liquid phase temperature efficiency is less than the set threshold Aref (or 0) and the refrigerant state is not stable after a predetermined time has elapsed from the start of operation (NO in step ST4), the first expansion device 15 The control target is controlled in a direction to reduce the opening degree (step ST6). Specifically, the preset suction superheat degree SHsref, which is a preset operation condition, is changed so as to increase by a predetermined amount, and the suction superheat degree SHs at the suction position becomes the changed set suction superheat degree SHsref. The opening degree of the first expansion device 15 is controlled. Then, the intake gas temperature of the compressor 11 rises and the discharge temperature of the compressor 11 rises.

  After the first expansion device 15 is controlled, it is determined again whether or not the index related to the liquid phase temperature is equal to or higher than the set threshold Aref from the start of operation until a predetermined time has elapsed. Thereby, it is determined whether or not the state of the refrigerant in each part of the refrigerant circuit 1A is stable (step ST7). Even after the control of the first expansion device 15 is performed, the liquidus temperature efficiency remains below the set threshold Aref (or 0) and it is determined that the refrigerant state is not stable (NO in step ST4) ), It is determined whether or not the discharge temperature of the compressor 11 is within an allowable range (step ST8). If the discharge temperature is within the allowable range (YES in step ST8), the set suction superheat degree SHsref is changed by a predetermined amount, and the opening degree of the first expansion device 15 is reduced (steps ST6 to ST8). On the other hand, when the discharge temperature exceeds the allowable range (NO in step ST8), the refrigerant amount determination mode ends.

  If the index related to the liquid phase temperature becomes equal to or higher than the set threshold Aref after the control target of the first expansion device 15 is changed (YES in step ST7), it is determined that the refrigerant state is stable, and the index related to the liquid phase temperature efficiency. Is stored in the storage unit 44 as the reference value RV. Further, the changed reference discharge superheat degree SHdref when the refrigerant state is stabilized is stored together with the reference value RV as an operation condition (step ST9).

  According to the first embodiment, in the first refrigerant amount determination mode, the reference value differs depending on whether the index related to the liquid phase temperature is equal to or higher than the set threshold Aref and the index related to the liquid phase temperature is less than the set threshold Aref. RV is set. For this reason, when setting the reference value RV in consideration of the relationship between the specified enclosed refrigerant amount in the refrigerant circuit 1A, the device connection conditions, and the operating conditions, any length of extension piping within the device specification range is connected. Even if it has been done, it is possible to set a reference value RV used for determining whether or not refrigerant leakage is appropriate.

  That is, when the refrigerant amount determination mode is performed in a state where the extension pipe is long, an index related to the refrigerant amount cannot be measured, and thus a state in which the reference value RV for detecting refrigerant leakage cannot be generated occurs. Thus, when the connection conditions or components of each device in the air conditioner 1 are different, it is difficult to derive the reference value RV for determining the suitability of the refrigerant amount. On the other hand, in the air conditioner 1 of FIG. 1, in the first refrigerant amount determination mode, an index related to the liquid phase temperature equal to or higher than the set threshold value Aref in which the refrigerant is stable is stored in the storage unit 44 as the reference value RV. Yes. For this reason, no matter what connection state the air conditioner 1 is installed in, the state in which the refrigerant is stable at the time of the initial installation is set as the reference value RV. Therefore, according to the installation structure of the air conditioner 1, it is possible to create the reference value RV that can accurately determine the suitability of refrigerant leakage.

  Furthermore, in the refrigerant amount determination mode, it is possible to set the reference value RV for accurately determining the decrease in the refrigerant not only in the case of the cooling channel but also in the case of the heating channel. In the conventional determination of the refrigerant amount, the suitability determination of the refrigerant amount during the cooling operation is performed, but it does not correspond to the suitability determination of the refrigerant amount during the heating operation. In addition, if the refrigerant amount determination mode is performed in a state where the extension pipe is short even within the range specified by the equipment in the heating flow path, there is a tendency that high-pressure protection is likely to occur. On the other hand, in FIG. 1, even when the refrigerant amount determination mode is executed in the heating channel, the index related to the liquidus temperature does not rise above the set threshold Aref, and the high pressure protection control is executed. A reference value RV corresponding to this is set. For this reason, it is possible to accurately determine the decrease of the refrigerant not only in the case of the cooling flow path but also in any case of the heating flow path.

  Further, when the air conditioner 1 has the receiver 16 in the refrigerant circuit 1A, when the excess refrigerant in the liquid reservoir is stored on the high-pressure side in the refrigerant amount determination mode in order to store the reference value RV, an abnormally high pressure (high pressure Operation may stop due to protection control. On the other hand, by setting that the high pressure protection control is activated as the reference value RV, even if the excess refrigerant remains in the receiver 16 without accumulating the refrigerant on the high pressure side, the excess refrigerant in the receiver 16 is removed. Refrigerant leakage can be detected before cutting.

  Further, when the operating condition is changed so that the condition changing unit 45b reduces the opening degree of the first expansion device 15 until the index related to the liquid phase temperature becomes larger than the set threshold value Aref in the first refrigerant amount determination mode, the reference value The determination unit 45c stores, in the storage unit 44, the reference discharge superheat degree SHdref when the index related to the liquidus temperature is equal to or higher than the set threshold value Aref as the changed operating condition. As described above, by combining the operating conditions in the first refrigerant amount determination mode and the second and subsequent refrigerant amount determination modes, it is possible to accurately determine the decrease in the refrigerant.

Embodiment 2. FIG.
FIG. 5 is a refrigerant circuit diagram showing Embodiment 2 of the air conditioner of the present invention, and the air conditioner 100 will be described with reference to FIG. In addition, in the air conditioner 100 of FIG. 5, the site | part which has the same structure as the air conditioner 1 of FIG. 1 attaches | subjects the same code | symbol, and abbreviate | omits the description. The air conditioner 100 of FIG. 5 is different from the air conditioner 1 of FIG. 1 in the structure of the receiver 116.

  In the air conditioner 100 of FIG. 5, the receiver 116 is a heat recovery type intermediate pressure receiver, and has a structure in which a pipe connecting the flow path switching device 12 and the suction side of the compressor 11 passes through the receiver. . The refrigerant flowing from the flow path switching device 12 to the suction side of the compressor 11 is cooled by the refrigerant stored in the receiver 116 and is sucked into the compressor 11.

  Even when the receiver 116 as in the second embodiment uses a heat recovery type receiver, as in the first embodiment, in the first refrigerant amount determination mode, the index related to the liquid phase temperature is equal to or higher than the set threshold Aref. A different reference value RV is set depending on the case and the case where the index related to the liquidus temperature is less than the set threshold value Aref. For this reason, when setting the reference value RV in consideration of the relationship between the specified enclosed refrigerant amount in the refrigerant circuit 1A, the device connection conditions, and the operating conditions, any length of extension piping within the device specification range is connected. Even if it has been done, it is possible to set a reference value RV used for determining whether or not refrigerant leakage is appropriate.

Embodiment 3. FIG.
FIG. 6 is a refrigerant circuit diagram showing Embodiment 3 of the air conditioner of the present invention. The air conditioner 200 will be described with reference to FIG. In addition, in the air conditioner 200 of FIG. 6, the part which has the same structure as the air conditioner 1 of FIG. 1 is attached | subjected, and the description is abbreviate | omitted. The air conditioner 200 of FIG. 6 is different from the air conditioner 1 of FIG. 1 in that only the connection position of the receiver 216 and one throttling device 215 are provided.

  The expansion device 215 in FIG. 6 is disposed between the outdoor heat exchanger 13 and the connection pipe 3, and the receiver 216 is disposed on the suction side of the compressor 11. Also in the third embodiment, as in the first embodiment, in the first refrigerant amount determination mode, the index related to the liquid phase temperature is greater than or equal to the set threshold Aref and the index related to the liquid phase temperature is less than the set threshold Aref. A different reference value RV is set depending on. For this reason, when setting the reference value RV in consideration of the relationship between the specified enclosed refrigerant amount in the refrigerant circuit 1A, the device connection conditions, and the operating conditions, any length of extension piping within the device specification range is connected. Even if it has been done, it is possible to set a reference value RV used for determining whether or not refrigerant leakage is appropriate.

  The embodiment of the present invention is not limited to the above embodiment. For example, in the first to third embodiments, the case where one outdoor unit 10 and one indoor unit 20 are provided is illustrated, but a plurality of outdoor units 10 and indoor units 20 may be provided. Moreover, in the said Embodiment 1-3, although the case where the parameter | index regarding liquid phase temperature is liquid temperature efficiency is illustrated, the parameter | index regarding liquid phase temperature should just be sufficient, for example, the total transmission of the outdoor heat exchanger 13 is sufficient. The phase area ratio AL% indicating the heat transfer area of the liquid phase relative to the heat area may be used, or the degree of supercooling SC of the outdoor heat exchanger 13 may be used.

  1, 100, 200 Air conditioner, 1A refrigerant circuit, 2, 3 connection piping, 10 outdoor unit, 11 compressor, 12 flow path switching device, 13 outdoor heat exchanger, 13A, 13B heat exchanger, 14 outdoor blower, 15 First throttle device, 16, 116, 216 Receiver, 17 Second throttle device, 20 Indoor unit, 21 Indoor heat exchanger, 22 Indoor blower, 30 Condition detector, 31 Discharge sensor, 32 Outdoor temperature sensor, 33 Condensing temperature Sensor, 34 Liquid side temperature sensor, 35 Inlet temperature sensor, 36 Evaporation temperature sensor, 37 Outlet temperature sensor, 38 Indoor temperature sensor, 39 Suction sensor, 40 Control device, 41 Operation control unit, 42 Index calculation unit, 43 Refrigerant amount determination Unit, 44 storage unit, 45 reference setting unit, 45a index determining unit, 45b condition changing unit, 45c reference value determining unit, 215 aperture Device, Aref setting threshold, RV reference value, SC supercooling degree, SHd discharge superheat degree, SHdref reference discharge superheat degree, SHs suction superheat degree, SHsref set suction superheat degree.

Claims (8)

A refrigerant circuit having a condenser;
A state detector for detecting the state of the refrigerant in the refrigerant circuit;
The refrigerant circuit controls the refrigerant circuit based on the refrigerant state detected by the state detector, and controls the operation of the refrigerant circuit when determining the suitability of the refrigerant quantity in the refrigerant circuit. And a control device having a function of executing the judgment mode,
The controller is
An operation control unit for controlling the refrigerant circuit based on operation conditions set in advance in the refrigerant amount determination mode;
An index calculator that calculates an index related to the liquid phase temperature of the condenser from the state of the refrigerant detected by the state detector when the refrigerant amount determination mode is executed;
A reference setting unit that sets, as a reference value, an index related to the liquid phase temperature calculated in the index calculation unit during the first refrigerant amount determination mode;
A storage unit for storing a reference value set in the reference setting unit;
In the second and subsequent refrigerant quantity determination modes, the refrigerant quantity in the refrigerant circuit is reduced by comparing the index related to the liquid phase temperature calculated in the index calculation unit with the reference value stored in the storage unit. A refrigerant amount determination unit for determining whether or not
With
The reference setting unit includes:
An index determination unit that determines whether an index related to the liquidus temperature is equal to or higher than a set threshold;
When the index determination unit determines that the index related to the liquid phase temperature is less than the set threshold, the condition change unit changes the operation condition in the operation control unit until the index related to the liquid phase temperature becomes larger than the set threshold. When,
When it is determined that the index related to the liquid phase temperature is equal to or higher than the set threshold value under the preset operating condition, the index related to the liquid phase temperature equal to or higher than the set threshold value is stored in the storage unit as a reference value, and the operating condition is set. When it is determined that the index related to the liquid phase temperature is greater than or equal to the set threshold after the change is made, the reference value determination is stored in the storage unit as the reference value related to the liquid phase temperature under the changed operating condition And an air conditioner. The reference value determination unit stores the changed operation condition when the index related to the liquid phase temperature is larger than the set threshold after the change of the operation condition, together with the reference value, in the storage unit.
When the operation condition after the change is stored together with the reference value in the storage unit, the operation control unit uses the operation condition after the change stored in the storage unit in the second and subsequent refrigerant amount determination modes. The air conditioner according to claim 1, which controls the refrigerant circuit. The refrigerant circuit has a compressor,
The operation control unit is configured to control the refrigerant circuit so that a suction superheat degree in the compressor becomes the set suction superheat degree, with a set suction superheat degree in the compressor as a preset operation condition.
The condition changing unit increases the set suction superheat degree by a predetermined amount until the index related to the liquid phase temperature becomes larger than the set threshold when it is determined that the index related to the liquid phase temperature is less than the set threshold. It changes the operating conditions in the volume judgment mode.
The reference value determining unit stores the reference discharge superheat degree in the compressor when the index related to the liquidus temperature is larger than a set threshold value as the changed operating condition in the storage unit,
When the operation condition after the change is stored in the storage unit together with the reference value, the operation control unit is configured to store the reference discharge overheat in which the discharge superheat degree is stored in the storage unit in the second and subsequent refrigerant amount determination modes. The air conditioner according to claim 2, wherein the refrigerant circuit is controlled so as to have a degree.   The air conditioner according to any one of claims 1 to 3, wherein the index related to the liquid phase temperature is a liquid temperature efficiency in the condenser.   The air conditioner according to claim 4, wherein the setting threshold is set to a value of 0.3 to 0.9. The refrigerant circuit has a compressor,
The operation control unit has a function of executing high-pressure protection control that restricts the operation of the compressor when the pressure of the refrigerant discharged from the compressor is larger than a set pressure value.
In the first refrigerant amount determination mode, the reference setting unit stores, in the storage unit, that the high pressure protection control is activated when the high pressure protection control by the operation control unit is activated.
The refrigerant amount determination unit determines that the refrigerant amount in the refrigerant circuit has not decreased when the high-pressure protection control by the operation control unit is activated in the second or subsequent refrigerant amount determination mode. The air conditioner of any one of Claims.   The air conditioner according to any one of claims 1 to 6, wherein the refrigerant amount determination unit determines that the refrigerant has not decreased when an index related to the liquidus temperature is greater than a set threshold value.   The air conditioner according to any one of claims 1 to 7, wherein the refrigerant circuit includes a receiver that stores excess refrigerant.

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