JP2016014512A - Freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezer including a refrigerant jacket provided in a refrigerant circuit and cooing a power element by refrigerant flowing between expansion valve and an evaporator, capable of suppressing the generation of dew condensation on the power element and a peripheral member of the power member resulting from a transient reduction in the pressure of the refrigerant flowing in the refrigerant jacket at a time of starting operation.SOLUTION: A refrigerant jacket (29) cooling a power element (72) by refrigerant flowing between an expansion valve (24) and an evaporator (23) is provided in a refrigerant circuit (10) of a freezer (1). A control unit (8) exerts a dew condensation protective control to restrict a degree of opening of the expansion valve (24) to a large degree of opening side if a dew condensation generation condition for determining that dew condensation is generated on the power element (72) or a peripheral member of the power element (72) is satisfied.

Description

  The present invention relates to a refrigeration apparatus, and more particularly to a refrigeration apparatus in which a refrigerant jacket for cooling a power element with a refrigerant flowing between an expansion valve and an evaporator is provided in a refrigerant circuit.

  2. Description of the Related Art Conventionally, there is an air conditioner as a refrigeration apparatus provided with a refrigerant jacket that cools a power element with refrigerant flowing between an expansion valve and an outdoor heat exchanger that functions as an evaporator in a refrigerant circuit. Specifically, this refrigeration apparatus is configured by connecting a compressor, an indoor heat exchanger or an outdoor heat exchanger as a radiator, an expansion valve, an outdoor heat exchanger or an indoor heat exchanger as an evaporator. And a control unit that has electric parts including a power element and performs operation control. As described above, the refrigerant circuit is provided with the refrigerant jacket that cools the power element with the refrigerant flowing between the expansion valve and the outdoor heat exchanger that functions as an evaporator.

  And as shown in patent document 1 (Unexamined-Japanese-Patent No. 2010-25374) as such a freezing apparatus, a control part determines with the dew condensation having generate | occur | produced in the power element or the peripheral member of the power element. In this case (that is, when the dew condensation generation condition is satisfied), the amount of heat generated by the power element is increased by performing control to increase the rotation speed of the compressor so as to suppress dew condensation in the power element and its vicinity. There is.

  By the way, when the operation is stopped after the operation is stopped or when the heating operation is started after the defrost operation or when the operation is started after the operation is switched, the refrigerant becomes transiently insufficient on the evaporator side. The pressure of the flowing refrigerant (low pressure of the refrigeration cycle) may decrease excessively. Then, such a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket causes a decrease in the temperature of the refrigerant jacket, which causes dew condensation in the power element and the vicinity thereof.

  Here, with respect to the dew condensation in the power element and the vicinity thereof caused by a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation from such operation stop or operation switching, the above conventional compressor It is conceivable to apply control that increases the rotational speed.

  However, in the control for increasing the rotational speed of the conventional compressor, the increase in the heat generation amount of the power element cannot follow the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket, and the refrigerant flowing through the refrigerant jacket at the start of operation Condensation in the power element and its vicinity due to a transient drop in pressure may not be suppressed. Further, in the control for increasing the rotational speed of the conventional compressor, the flow rate of the refrigerant sucked into the compressor from the evaporator side is increased, so that the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is rather There is even a risk of a progressive drop in the process.

  An object of the present invention is to provide a refrigeration apparatus in which a refrigerant jacket for cooling a power element by a refrigerant flowing between an expansion valve and an evaporator is provided in a refrigerant circuit, and the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is transient. An object of the present invention is to be able to suppress dew condensation in the power element and its vicinity due to the decrease.

  A refrigerating apparatus according to a first aspect includes a refrigerant circuit configured by connecting a compressor, a radiator, an expansion valve, and an evaporator, and an electric component including a power element, and performs control of operation. Part. The refrigerant circuit is provided with a refrigerant jacket that cools the power element by the refrigerant flowing between the expansion valve and the evaporator. The control unit performs condensation protection control that restricts the opening degree of the expansion valve to the large opening side when the condensation condition that determines that condensation occurs in the power element or the peripheral member of the power element is satisfied. Do.

  Here, as described above, when the condensation occurrence condition is satisfied, the opening degree of the expansion valve is forcibly increased by performing the condensation protection control that restricts the opening degree of the expansion valve to the large opening degree side. . For this reason, the refrigerant existing upstream of the expansion valve is not affected by the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation (low pressure in the refrigeration cycle). By promptly flowing into the refrigerant jacket side, a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket can be mitigated, and a temperature decrease in the refrigerant jacket can be suppressed. Here, in the case where a plurality of expansion valves are provided in the refrigerant circuit, in the refrigerant circuit, in order to make it easy to obtain the action of promptly flowing the refrigerant existing upstream of the expansion valve to the refrigerant jacket side. The expansion valve for reducing the pressure to the low pressure of the refrigeration cycle located upstream of the refrigerant jacket and closest to the refrigerant jacket is preferably controlled.

  Thereby, the dew condensation in the power element and its vicinity resulting from the transient fall of the pressure of the refrigerant which flows through the refrigerant jacket at the time of the start of operation can be controlled here.

  In addition, whether or not the condition for generating condensation is satisfied, such as the temperature of the refrigerant jacket, the power element, and the evaporator, such as the temperature of the refrigerant jacket, the temperature of the power element, and / or the temperature of the refrigerant flowing through the evaporator. It is conceivable to make a determination based on the temperature of a part that causes condensation or a device that causes condensation. For example, whether the temperature of the refrigerant jacket is lower than the jacket condensation generation temperature, whether the power element temperature is lower than the power element condensation generation temperature, and / or the evaporation temperature and the liquid side temperature of the refrigerant flowing through the evaporator, It is possible to determine whether or not the difference in temperature exceeds the dew condensation temperature difference. Here, the dew generation temperature may be a fixed temperature value, but is variable depending on the ambient temperature of the power element and the refrigerant jacket in consideration of the change of the dew point temperature depending on the ambient temperature of the power element and the refrigerant jacket such as the outside air temperature. It may be a temperature value to be set. In this way, if it is determined whether or not the condensation occurrence condition is satisfied based on the temperature of the component that causes condensation such as the temperature of the refrigerant jacket, the power element, and the evaporator, or the equipment that causes the condensation, the power element or It is possible to appropriately determine whether or not condensation has occurred on the peripheral members of the power element.

  The refrigeration apparatus according to the second aspect is the refrigeration apparatus according to the first aspect, wherein the controller increases the lower limit opening of the expansion valve to increase the opening of the expansion valve to a larger opening in the condensation protection control. Restrict.

  In the dew condensation protection control, for example, it is conceivable to limit the expansion valve to the large opening side by forcibly increasing the opening degree of the expansion valve from the current opening degree. However, during the operation of the refrigeration system, the opening degree of the expansion valve is controlled so that the superheat degree of the refrigerant sucked into the compressor becomes the target superheat degree (superheat degree control), or the refrigerant discharged from the compressor In some cases, some control is performed such that the temperature is controlled to be the target discharge temperature (discharge temperature control). As described above, when the opening degree control of the expansion valve such as the superheat degree control or the discharge temperature control is performed, the opening degree of the expansion valve is opened while continuing the opening degree control of the expansion valve such as the superheat degree control or the discharge temperature control. It is preferable to employ dew condensation protection control capable of limiting the degree to the large opening degree side.

  Therefore, here, as described above, as the dew condensation protection control, the opening degree of the expansion valve is limited to the large opening degree side by increasing the lower limit opening degree of the expansion valve.

  Thus, here, even when the opening degree control of the expansion valve such as superheat degree control and discharge temperature control is performed during operation, the condensation protection control is performed while continuing the opening degree control of the expansion valve. It can be carried out.

  The refrigeration apparatus according to the third aspect is the refrigeration apparatus according to the first or second aspect, wherein the control unit determines that no condensation occurs on the power element or a peripheral member of the power element. Condensation protection control is performed until the value is satisfied.

  Here, as described above, the condensation protection control is performed until the condensation suppression condition is satisfied. That is, here, the dew condensation protection control is performed until the dew condensation is suppressed in the power element and its vicinity due to the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation.

  Thereby, it is confirmed here that the condensation in the power element and its vicinity due to the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is suppressed, and the condensation protection control can be terminated.

  Further, whether or not the dew condensation suppression condition is satisfied is similar to the dew condensation occurrence condition, such as the temperature of the refrigerant jacket, the temperature of the power element, and / or the temperature of the refrigerant flowing through the evaporator, It is conceivable to make a determination based on the temperature of a part that causes condensation, such as the temperature of an evaporator, or the temperature of a device that causes condensation. For example, whether the temperature of the refrigerant jacket exceeds the jacket condensation suppression temperature, whether the temperature of the power element exceeds the power element condensation suppression temperature, and / or the evaporation temperature and liquid side temperature of the refrigerant flowing through the evaporator, It can be determined by whether or not the temperature difference is less than the dew condensation suppression temperature difference. In this case, in order to clearly detect that condensation is suppressed, the condensation suppression temperature is set to a temperature value higher than the condensation occurrence temperature, and the condensation suppression temperature difference is a temperature value lower than the condensation occurrence temperature difference. It is preferable to set to. In addition, the dew condensation suppression temperature may be a fixed temperature value, but is variable depending on the ambient temperature of the power element and the refrigerant jacket in consideration that the dew point temperature varies depending on the ambient temperature of the power element and the refrigerant jacket such as the outside air temperature. The temperature value may be a certain value. Thus, if it is determined whether or not the dew condensation suppression condition is satisfied based on the temperature of the refrigerant jacket, the power element, the part where condensation occurs such as the temperature of the evaporator, or the equipment that causes the condensation, the power element or It is possible to appropriately determine whether or not condensation on the peripheral members of the power element is suppressed.

  In the refrigeration apparatus according to the fourth aspect, in the refrigeration apparatus according to the third aspect, the control unit does not satisfy the dew condensation suppression condition even when the dew condensation protection control is performed, and the power element or the peripheral member of the power element When the standby condition for determining that condensation is in progress is satisfied, standby control is performed to stop the compressor.

  When the transient drop in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is excessive, there is a possibility that the dew condensation in the power element and its vicinity due to this will not be suppressed even if the dew condensation protection control is performed. In such a case, even if the dew condensation protection control is continued, the dew condensation on the power element or the peripheral member of the power element proceeds, and there is a risk of causing a failure of the power element or an electrical component near the power element.

  Therefore, here, as described above, even if the dew condensation protection control is performed, if the dew condensation suppression condition is not satisfied and the standby condition is satisfied, the dew condensation on the power element or the peripheral member of the power element is continued while continuing the operation. The control for stopping the compressor is temporarily given, and standby control for stopping the compressor is performed.

  As a result, here, even if the dew condensation protection control is performed, the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is excessive so that the dew condensation on the power element or the peripheral member of the power element proceeds. In addition, priority can be given to preventing failure of the power element and electrical components in the vicinity of the power element.

  Whether or not the standby condition is satisfied may be determined based on the time during which the condensation protection control is continued in a state where the condensation suppression condition is not satisfied. For example, the determination can be made based on whether or not the time after satisfying the dew condensation occurrence condition has reached the standby time. Here, as a standby condition, not only the standby time but also a determination based on the temperature of a component such as a refrigerant jacket or a power element that causes condensation, such as the temperature of the refrigerant jacket and / or the temperature of the power element. You may make it add. For example, depending on whether or not the time when the refrigerant jacket temperature is lower than the jacket standby temperature and / or the time when the power element temperature is lower than the power element standby temperature has reached the standby time after satisfying the dew condensation generation condition Can be determined. In this case, in order to clearly detect that the dew condensation is in progress, it is preferable to set the standby temperature to a temperature value lower than the dew condensation temperature and higher than the dew condensation suppression temperature. The standby temperature may be a fixed temperature value, but is variable depending on the ambient temperature of the power element and the refrigerant jacket in consideration of the dew point temperature changing depending on the ambient temperature of the power element and the refrigerant jacket such as the outside air temperature. It may be a temperature value. In this way, if it is determined whether or not the standby condition is satisfied based on the time during which the dew condensation protection control is continued in a state where the dew condensation suppression condition is not satisfied, the dew condensation is progressing in the power element or the peripheral member of the power element. Whether or not can be determined appropriately.

  In the refrigeration apparatus according to the fifth aspect, in the refrigeration apparatus according to the fourth aspect, the control unit activates the compressor after the standby control and determines again whether or not the dew condensation generation condition is satisfied. The control unit performs the condensation protection control again when the condensation occurrence condition is satisfied, and performs the standby control again when the condensation suppression condition is not satisfied and the standby condition is satisfied even when the condensation protection control is performed. .

  Before and after the operation including condensation protection control is performed, the distribution state of the refrigerant in the refrigerant circuit changes, so the following is compared with the degree of transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of the previous operation. In some cases, the degree of transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of the operation becomes small.

  Therefore, as described above, after the standby control, the compressor is started to determine again whether the dew condensation generation condition is satisfied. For this reason, if the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is so small that it does not satisfy the dew condensation generation condition, the operation should be continued without performing dew condensation protection control. Can do. In this case, as described above, the condensation protection control is performed again when the condensation occurrence condition is satisfied. For this reason, a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation satisfies the dew generation condition, but if the dew condensation control is small enough to suppress dew condensation control, the dew condensation protection control is performed. By performing again, the dew condensation suppression condition is satisfied and the operation can be continued. In this case, as described above, even when the dew condensation protection control is performed, if the dew condensation suppression condition is not satisfied and the standby condition is satisfied, the standby control is performed again. For this reason, when the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is not reduced to the extent that dew condensation is suppressed by the dew condensation protection control, standby control can be performed again. That is, a series of judgments and controls including standby control and subsequent compressor start-up until a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is reduced to the extent that dew condensation is suppressed by dew condensation protection control. Can be repeated.

  Thereby, here, even if the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is excessive, it is caused by the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation. Condensation in the power element and its vicinity can be suppressed.

  In the refrigeration apparatus according to the sixth aspect, in the refrigeration apparatus according to the fifth aspect, when the number of times of standby control is equal to or greater than the upper limit number of standby times, the control unit abnormally stops without starting the compressor. .

  When a series of judgments and controls including standby control and subsequent compressor start-up are repeated many times, the power element and its vicinity caused by a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation It is necessary to suspect that the dew condensation is excessive or other abnormal factors such as failure of expansion valves and sensors.

  Therefore, here, as described above, when the number of standby control times exceeds the upper limit standby frequency, the compressor is not started by abnormally stopping.

  As a result, various abnormalities including excessive dew condensation in the power element and its vicinity due to a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation, such as by displaying an abnormal code together with an abnormal stop, are here. It can be informed that inspection including factors is necessary.

  In the refrigeration apparatus according to the seventh aspect, in any one of the refrigeration apparatuses according to the first to sixth aspects, the control unit performs start control for setting the opening degree of the expansion valve to the start opening degree at the start of operation. ing. Then, when it is determined that the dew condensation generation condition is satisfied, the control unit performs dew condensation suppression start opening correction for correcting the start opening to be increased.

  Here, as described above, activation control is performed in which the opening of the expansion valve is set to the activation opening at the start of operation. Since a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation also occurs during start-up control, how to set the start-up opening degree of the expansion valve during start-up control This will affect the degree of transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket.

  Therefore, here, as described above, when it is determined that the dew generation condition is satisfied, the dew condensation suppression start opening correction is performed so that the start opening is increased. That is, when an operation that satisfies the dew generation condition is performed, it is considered that condensation is likely to occur in the power element and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation. The starting opening is corrected so as to increase. For this reason, for example, when an operation that has been determined to satisfy the dew condensation occurrence condition is performed, the start opening is corrected so as to increase, and this corrected start opening is used for the next start control. can do. Then, not only when the dew condensation generation condition is satisfied, but also at the time of starting control, the opening degree of the expansion valve can be increased, and the refrigerant existing on the upstream side of the expansion valve is allowed to flow quickly into the refrigerant jacket side, A transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket can be mitigated, and a temperature decrease in the refrigerant jacket can be suppressed.

  Thereby, here, at the time of starting the operation including the start-up control, it is possible to contribute to suppression of dew condensation in the power element and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket.

  For example, when the above standby control is performed, the startup opening corrected so as to increase at the subsequent startup of the compressor is used as the startup opening of the expansion valve. For this reason, at the time of starting the compressor after standby control, a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is likely to be reduced, and even at the time of starting the compressor after standby control. In addition, it is possible to contribute to suppression of dew condensation in the power element and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket.

  In the refrigeration apparatus according to the eighth aspect, in the refrigeration apparatus according to the seventh aspect, the control unit determines that the refrigerant sucked into the compressor is in a wet state that requires protection of the compressor. When the wetness generation condition is satisfied, the wetness suppression start-up opening degree correction is performed so that the start-up opening degree is reduced.

  When the above-described dew condensation suppression start-up opening degree correction is performed, the start-up opening degree of the expansion valve becomes large. If the start-up opening degree becomes too large, there is a risk that liquid compression in which liquid refrigerant is sucked into the compressor may occur. .

  Therefore, here, as described above, when it is determined that the wetness generation condition is satisfied, the wetness suppression start-up opening correction is performed so that the start-up opening is corrected to be small. In other words, when an operation that satisfies the wetness generation condition is performed, the refrigerant sucked into the compressor is regarded as being in a wet state that requires protection of the compressor, and the starting opening is corrected to be small. To do. For this reason, for example, when an operation determined to satisfy the wetness generation condition is performed, the start opening is corrected to be small, and the corrected start opening is used for the next start control. can do. Then, it is possible to prevent the refrigerant sucked into the compressor from entering a wet state that requires protection of the compressor, and it is possible to prevent the start opening from becoming too large due to the dew condensation suppression start opening correction.

  Thereby, here, at the start of operation including the start-up control, the refrigerant sucked into the compressor is prevented from entering a wet state that requires protection of the compressor, and the pressure of the refrigerant flowing through the refrigerant jacket is transiently changed. It is possible to contribute to suppression of dew condensation in the power element and the vicinity thereof due to excessive decrease.

  In addition, it is conceivable to determine whether or not the wetness generation condition is satisfied based on the temperature and pressure indicating the operation state of the compressor. For example, the determination can be made based on whether or not the superheat degree of the refrigerant discharged from the compressor is lower than the wetness generated superheat degree. As described above, if it is determined whether or not the wetness generation condition is satisfied based on the temperature and pressure indicating the operation state of the compressor, whether the refrigerant sucked into the compressor is in a wet state that requires protection of the compressor. Whether or not can be determined appropriately.

  As described above, according to the present invention, the following effects can be obtained.

  In the refrigeration apparatus according to the first aspect, it is possible to suppress dew condensation in the power element and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation.

  In the refrigeration apparatus according to the second aspect, even when the opening degree control of the expansion valve such as the superheat degree control and the discharge temperature control is performed during operation, the opening degree control of the expansion valve is continued, Condensation protection control can be performed.

  In the refrigeration apparatus according to the third aspect, the dew condensation protection control is terminated after confirming that dew condensation has been suppressed in the power element and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation. be able to.

  In the refrigeration apparatus according to the fourth aspect, the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation transiently decreases so that the dew condensation on the power element or the peripheral member of the power element proceeds even if the dew condensation protection control is performed. In the case where the power element is excessive, priority can be given to preventing the failure of the power element and the electrical components in the vicinity of the power element.

  In the refrigeration apparatus according to the fifth aspect, even if the transient drop in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is excessive, the transient pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is Condensation in the power element and its vicinity due to the reduction can be suppressed.

  In the refrigeration system according to the sixth aspect, excessive dew condensation in the power element and its vicinity due to a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket at the start of operation is displayed by displaying an abnormal code together with an abnormal stop. It is possible to inform that inspection including various abnormal factors is necessary.

  In the refrigeration apparatus according to the seventh aspect, at the start of operation including start-up control, it is possible to contribute to suppression of dew condensation in the power element and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket. .

  In the refrigeration apparatus according to the eighth aspect, at the start of operation including start-up control, the refrigerant sucked into the compressor is prevented from entering a wet state that requires protection of the compressor, and the refrigerant flowing through the refrigerant jacket is prevented. It can contribute to suppression of dew condensation in the power element and its vicinity due to a transient drop in pressure.

It is a schematic block diagram of the air conditioning apparatus as one Embodiment of the freezing apparatus concerning this invention. It is sectional drawing which shows the peripheral member of a power element and a power element. It is a side view which shows the peripheral member of a power element and a power element. It is a control block diagram of an air conditioning apparatus. It is a flowchart which shows control of the air conditioning apparatus containing dew condensation protection control. It is a flowchart which shows control of the air conditioning apparatus containing the dew condensation protection control and standby | waiting control of the modification 1. It is a flowchart which shows the control of the air conditioning apparatus containing the dew condensation protection control of the modification 2, standby control, starting control, and dew condensation suppression starting opening degree correction | amendment. It is a flowchart which shows the control of the air conditioning apparatus containing the dew condensation protection control of the modified example 3, standby control, start-up control, dew condensation suppression starting opening degree correction | amendment, and wetness suppression starting opening degree correction | amendment. It is a schematic block diagram of the air conditioning apparatus of another modification. It is a schematic block diagram of the air conditioning apparatus of another modification.

  Hereinafter, an embodiment of a refrigeration apparatus according to the present invention will be described based on the drawings. In addition, the specific structure of embodiment of the freezing apparatus concerning this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) Configuration of Air Conditioner (Refrigeration Device) FIG. 1 is a schematic configuration diagram of an air conditioner 1 as an embodiment of a refrigeration device according to the present invention. FIG. 2 is a cross-sectional view showing the power element 72 and peripheral members of the power element 72. FIG. 3 is a side view showing the power element 72 and peripheral members of the power element 72. FIG. 4 is a control block diagram of the air conditioner 1.

  The air conditioner 1 is a device capable of cooling and heating a room such as a building by performing a vapor compression refrigeration cycle. The air conditioner 1 is mainly configured by connecting an outdoor unit 2 and an indoor unit 4. Here, the outdoor unit 2 and the indoor unit 4 are connected via a liquid refrigerant communication tube 5 and a gas refrigerant communication tube 6. That is, the vapor compression refrigerant circuit 10 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor unit 4 via the refrigerant communication pipes 5 and 6.

<Indoor unit>
The indoor unit 4 is installed indoors and constitutes a part of the refrigerant circuit 10. The indoor unit 4 mainly has an indoor heat exchanger 41.

  The indoor heat exchanger 41 is a heat exchanger that functions as a refrigerant evaporator during cooling operation to cool indoor air, and functions as a refrigerant radiator during heating operation to heat indoor air. The liquid side of the indoor heat exchanger 41 is connected to the liquid refrigerant communication tube 5, and the gas side of the indoor heat exchanger 41 is connected to the gas refrigerant communication tube 6.

  The indoor unit 4 has an indoor fan 42 for supplying indoor air as supply air after sucking indoor air into the indoor unit 4 and exchanging heat with the refrigerant in the indoor heat exchanger 41. That is, the indoor unit 4 has an indoor fan 42 as a fan that supplies indoor air as a heating source or cooling source of the refrigerant flowing through the indoor heat exchanger 41 to the indoor heat exchanger 41. Here, as the indoor fan 42, a centrifugal fan or a multiblade fan driven by an indoor fan motor 42a is used.

  Various sensors are provided in the indoor unit 4. Specifically, the indoor heat exchanger 41 includes an indoor heat exchange liquid side temperature sensor 49 that detects a refrigerant temperature Th2 on the liquid side of the indoor heat exchanger 41, and refrigerant in the intermediate portion of the indoor heat exchanger 41. An indoor heat exchanger intermediate temperature sensor 48 for detecting the temperature Th3 is provided. The indoor unit 4 is provided with an indoor temperature sensor 50 that detects the temperature Th1 of indoor air sucked into the indoor unit 4.

  The indoor unit 4 has an indoor side control unit 40 that controls the operation of each part constituting the indoor unit 4. And the indoor side control part 40 has the microcomputer, memory, etc. which were provided in order to control the indoor unit 4, and is with the remote control (not shown) for operating the indoor unit 4 separately. Control signals and the like can be exchanged between them, and control signals and the like can be exchanged with the outdoor unit 2.

<Outdoor unit>
The outdoor unit 2 is installed outside and constitutes a part of the refrigerant circuit 10. The outdoor unit 2 mainly includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, a refrigerant jacket 29, a first expansion valve 24, a receiver 25, a second expansion valve 26, a liquid A side closing valve 27 and a gas side closing valve 28 are provided.

  The compressor 21 is a device that compresses the low-pressure refrigerant of the refrigeration cycle until it reaches a high pressure. The compressor 21 has a hermetic structure in which a rotary type or scroll type positive displacement compression element (not shown) is rotationally driven by a compressor motor 21a whose frequency (number of rotations) can be controlled by an inverter. That is, the compressor 21 is configured to be able to control the operating capacity by changing the frequency (the number of rotations). The compressor 21 has a suction pipe 31 connected to the suction side and a discharge pipe 32 connected to the discharge side. The suction pipe 31 is a refrigerant pipe that connects the suction side of the compressor 21 and the four-way switching valve 22. The discharge pipe 32 is a refrigerant pipe that connects the discharge side of the compressor 21 and the four-way switching valve 22.

  The four-way switching valve 22 is a switching valve for switching the direction of refrigerant flow in the refrigerant circuit 10. During the cooling operation, the four-way switching valve 22 causes the outdoor heat exchanger 23 to function as a radiator for the refrigerant compressed in the compressor 21 and the indoor heat exchanger 41 for the refrigerant that has radiated heat in the outdoor heat exchanger 23. Switch to the cooling cycle state to function as an evaporator. That is, in the cooling operation, the four-way switching valve 22 is connected between the discharge side of the compressor 21 (here, the discharge pipe 32) and the gas side of the outdoor heat exchanger 23 (here, the first gas refrigerant pipe 33). (See the solid line of the four-way selector valve 22 in FIG. 1). Moreover, the suction side (here, the suction pipe 31) of the compressor 21 and the gas refrigerant communication pipe 6 side (here, the second gas refrigerant pipe 34) are connected (solid line of the four-way switching valve 22 in FIG. 1). See). Further, the four-way switching valve 22 causes the outdoor heat exchanger 23 to function as an evaporator of the refrigerant that has radiated heat in the indoor heat exchanger 41 during the heating operation, and the indoor heat exchanger 41 is compressed in the compressor 21. Switching to a heating cycle state that functions as a refrigerant radiator. That is, in the heating operation, the four-way switching valve 22 is connected to the discharge side (here, the discharge pipe 32) of the compressor 21 and the gas refrigerant communication pipe 6 side (here, the second gas refrigerant pipe 34). (Refer to the broken line of the four-way switching valve 22 in FIG. 1). In addition, the suction side of the compressor 21 (here, the suction pipe 31) and the gas side of the outdoor heat exchanger 23 (here, the first gas refrigerant pipe 33) are connected (four-way switching valve 22 in FIG. 1). See the dashed line). Here, the first gas refrigerant pipe 33 is a refrigerant pipe connecting the four-way switching valve 22 and the gas side of the outdoor heat exchanger 23. The second gas refrigerant pipe 34 is a refrigerant pipe that connects the four-way switching valve 22 and the gas-side closing valve 28.

  The outdoor heat exchanger 23 is a heat exchanger that functions as a refrigerant radiator that uses outdoor air as a cooling source during cooling operation, and functions as a refrigerant evaporator that uses outdoor air as a heating source during heating operation. The outdoor heat exchanger 23 has a liquid side connected to the liquid refrigerant pipe 35 and a gas side connected to the first gas refrigerant pipe 33. The liquid refrigerant pipe 35 is a refrigerant pipe that connects the liquid side of the outdoor heat exchanger 23 and the liquid refrigerant communication pipe 5 side.

  The first expansion valve 24 is a valve that reduces the high-pressure refrigerant of the refrigeration cycle radiated in the outdoor heat exchanger 23 to the intermediate pressure of the refrigeration cycle during the cooling operation. The first expansion valve 24 is a valve that reduces the intermediate-pressure refrigerant of the refrigeration cycle stored in the receiver 25 to the low pressure of the refrigeration cycle during heating operation. The first expansion valve 24 is provided in a portion of the liquid refrigerant pipe 35 near the outdoor heat exchanger 23. Here, an electric expansion valve is used as the first expansion valve 24.

  The receiver 25 is provided between the first expansion valve 24 and the second expansion valve 26. The receiver 25 is a container capable of storing a refrigerant having an intermediate pressure of the refrigeration cycle during the cooling operation and the heating operation.

  The second expansion valve 26 is a valve for reducing the intermediate-pressure refrigerant of the refrigeration cycle stored in the receiver 25 to the low pressure of the refrigeration cycle during the cooling operation. The second expansion valve 26 is a valve for reducing the high-pressure refrigerant of the refrigeration cycle radiated in the indoor heat exchanger 41 to the intermediate pressure of the refrigeration cycle during the heating operation. The second expansion valve 26 is provided in a portion of the liquid refrigerant pipe 35 near the liquid side closing valve 27. Here, an electric expansion valve is used as the second expansion valve 26.

  The refrigerant jacket 29 is a refrigerant that flows between the expansion valve (here, the first expansion valve 24) and the outdoor heat exchanger 23 through the power element 72 included as an electrical component that constitutes an inverter circuit such as the compressor motor 21a. It is a heat exchanger cooled by. Here, the refrigerant jacket 29 functions as a heat exchanger that cools the power element 72 with the high-pressure refrigerant of the refrigeration cycle before radiating heat in the outdoor heat exchanger 23 and being decompressed by the first expansion valve 24 during the cooling operation. . Further, during the heating operation, the refrigerant jacket 29 functions as a heat exchanger that cools the power element 72 with the low-pressure refrigerant of the refrigeration cycle after radiating heat in the indoor heat exchanger 41 and being decompressed by the first expansion valve 24. Such a refrigerant jacket 29 cools the power element 72 that generates heat at a high temperature during operation. In addition, here, the electrical component including the power element 72 is mounted on the substrate 70 as shown in FIGS. 2 and 3 (illustration of electrical components other than the power element 72 is omitted). The refrigerant jacket 29 is arranged so as to cover the portion where 72 is mounted. Here, the refrigerant jacket 29 has a structure in which a U-bent portion of the liquid refrigerant pipe 35 is supported by a refrigerant cooling member 71 that is in thermal contact with the power element 72. Here, the coolant cooling member 71 is a metal member such as aluminum.

  The liquid side shut-off valve 27 and the gas side shut-off valve 28 are valves provided at connection ports with external devices and pipes (specifically, the liquid refrigerant communication pipe 5 and the gas refrigerant communication pipe 6). The liquid side closing valve 27 is provided at the end of the liquid refrigerant pipe 35. The gas side closing valve 28 is provided at the end of the second gas refrigerant pipe 34.

  The outdoor unit 2 has an outdoor fan 36 for sucking outdoor air into the outdoor unit 2 and exchanging heat with the refrigerant in the outdoor heat exchanger 23 and then discharging the air to the outside. That is, the outdoor unit 2 includes an outdoor fan 36 as a fan that supplies outdoor air as a cooling source or a heating source of the refrigerant flowing through the outdoor heat exchanger 23 to the outdoor heat exchanger 23. Here, as the outdoor fan 36, a propeller fan or the like driven by an outdoor fan motor 36a is used.

  Various types of sensors are provided in the outdoor unit 2. Specifically, the suction pipe 31 is provided with a suction temperature sensor 43 that detects the temperature Ts of the low-pressure refrigerant in the refrigeration cycle sucked into the compressor 21. The discharge pipe 32 is provided with a discharge temperature sensor 44 that detects the temperature Td of the high-pressure refrigerant in the refrigeration cycle discharged from the compressor 21. The outdoor heat exchanger 23 includes an outdoor heat exchanger intermediate temperature sensor 45 that detects a refrigerant temperature Tm in an intermediate portion of the outdoor heat exchanger 23, and an outdoor that detects a refrigerant temperature Tb on the liquid side of the outdoor heat exchanger 23. A heat exchanger side temperature sensor 46 is provided. The outdoor unit 2 is provided with an outdoor air temperature sensor 47 that detects the temperature (outside air temperature) Ta of outdoor air sucked into the outdoor unit 2. The refrigerant cooling member 71 of the refrigerant jacket 29 is provided with a refrigerant cooling temperature sensor 51 that detects a representative temperature Tfin of the power element 72 and peripheral members of the power element 72 (such as the refrigerant jacket 29 and the substrate 70).

  The outdoor unit 2 has an outdoor side control unit 20 that controls the operation of each unit constituting the outdoor unit 2. The outdoor control unit 20 includes a microcomputer and a memory provided to control the outdoor unit 2, electric components including the power element 72, and the like, and the indoor unit 4 (that is, the indoor control unit). 40) can exchange control signals and the like.

<Refrigerant communication pipe>
The refrigerant communication pipes 5 and 6 are refrigerant pipes that are constructed on the site when the air conditioner 1 is installed, and have various lengths and pipe diameters depending on the installation conditions of the outdoor unit 2 and the indoor unit 4. Things are used.

<Control unit>
The air conditioner 1 can perform operation control of each device of the outdoor unit 2 and the indoor unit 4 by the control unit 8 including the indoor side control unit 40 and the outdoor side control unit 20. . That is, the indoor side control unit 40 and the outdoor side control unit 20 constitute a control unit 8 that performs operation control of the entire air conditioner 1 including refrigeration cycle operations such as cooling operation and heating operation. As shown in FIG. 4, the control unit 8 is connected so as to receive detection signals from the various sensors 43 to 51 and the like, and based on these detection signals and the like, various devices and valves 21 a, 22, and 24. , 26, 36a, 42a, etc. are connected so that they can be controlled.

  As described above, the air-conditioning apparatus 1 (refrigeration apparatus) includes the compressor 21, the radiator (in the heating operation, the indoor heat exchanger 41), the expansion valve (here, the first expansion valve 24), and the evaporator (heating). During operation, it includes the refrigerant circuit 10 configured by being connected to the outdoor heat exchanger 23), and a control unit 8 that has electric components including the power element 72 and performs operation control. Here, the refrigerant circuit 10 is provided with a refrigerant jacket 29 that cools the power element 72 with refrigerant flowing between the (first expansion valve 24) and the evaporator (outdoor heat exchanger 23 during heating operation). Yes. In the air conditioner 1, the control unit 8 performs the following refrigeration cycle operation and control.

(2) Basic operation | movement of air conditioning apparatus (refrigeration apparatus) Next, the basic operation | movement of the air conditioning apparatus 1 is demonstrated using FIGS. 1-4. As a basic operation, the air conditioner 1 functions as a cooling operation that is a refrigeration cycle operation in which the indoor heat exchanger 41 functions as a refrigerant evaporator and performs indoor cooling, and the indoor heat exchanger 41 functions as a refrigerant radiator. Thus, it is possible to perform a heating operation that is a refrigeration cycle operation for heating a room. Further, when frost is generated in the outdoor heat exchanger 23 during the heating operation, it is possible to temporarily perform a defrost operation for melting the frost adhering to the outdoor heat exchanger 23. These basic operations are performed by the control unit 8.

<Cooling operation>
During the cooling operation, the four-way switching valve 22 is switched to the cooling cycle state (state indicated by the solid line in FIG. 1).

  In the refrigerant circuit 10, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 21 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged.

  The high-pressure gas refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 23 through the four-way switching valve 22.

  The high-pressure gas refrigerant sent to the outdoor heat exchanger 23 performs heat exchange with the outdoor air supplied as a cooling source by the outdoor fan 36 in the outdoor heat exchanger 23 to dissipate heat to become a high-pressure liquid refrigerant. .

  The high-pressure liquid refrigerant radiated in the outdoor heat exchanger 23 is reduced to the intermediate pressure of the refrigeration cycle by the first expansion valve 24 and temporarily stored in the receiver 25.

  The intermediate-pressure refrigerant of the refrigeration cycle temporarily stored in the receiver 25 is reduced to the low pressure of the refrigeration cycle by the second expansion valve 26 to become a low-pressure gas-liquid two-phase refrigerant.

  The low-pressure gas-liquid two-phase refrigerant decompressed by the second expansion valve 26 is sent to the indoor heat exchanger 41 through the liquid side closing valve 27 and the liquid refrigerant communication pipe 5.

  The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchanger 41 evaporates by exchanging heat with indoor air supplied as a heating source by the indoor fan 42 in the indoor heat exchanger 41. As a result, the room air is cooled and then supplied to the room to cool the room.

  The low-pressure gas refrigerant evaporated in the indoor heat exchanger 41 is again sucked into the compressor 21 through the gas refrigerant communication pipe 6, the gas-side closing valve 28 and the four-way switching valve 22.

<Heating operation>
During the heating operation, the four-way switching valve 22 is switched to the heating cycle state (the state indicated by the broken line in FIG. 1).

  In the refrigerant circuit 10, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 21 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged.

  The high-pressure gas refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the four-way switching valve 22, the gas side closing valve 28 and the gas refrigerant communication pipe 6.

  The high-pressure gas refrigerant sent to the indoor heat exchanger 41 radiates heat by exchanging heat with indoor air supplied as a cooling source by the indoor fan 42 in the indoor heat exchanger 41 to become a high-pressure liquid refrigerant. . Thereby, indoor air is heated, and indoor heating is performed by being supplied indoors after that.

  The high-pressure liquid refrigerant radiated by the indoor heat exchanger 41 is sent to the second expansion valve 26 through the liquid refrigerant communication pipe 5 and the liquid side closing valve 27.

  The high-pressure liquid refrigerant sent to the second expansion valve 26 is decompressed to the intermediate pressure of the refrigeration cycle by the second expansion valve 26 and is temporarily stored in the receiver 25.

  The intermediate-pressure refrigerant of the refrigeration cycle temporarily stored in the receiver 25 is reduced to the low pressure of the refrigeration cycle by the first expansion valve 24 to become a low-pressure gas-liquid two-phase refrigerant.

  The low-pressure gas-liquid two-phase refrigerant decompressed by the first expansion valve 24 evaporates in the outdoor heat exchanger 23 by exchanging heat with outdoor air supplied as a heating source by the outdoor fan 36. Become a gas refrigerant.

  The low-pressure refrigerant evaporated in the outdoor heat exchanger 23 is again sucked into the compressor 21 through the four-way switching valve 22.

<Defrost operation>
At the time of the defrost operation, the four-way switching valve 22 is switched to the cooling cycle state (the state shown by the solid line in FIG. 1) as in the cooling operation. Then, a refrigeration cycle operation similar to the cooling operation is performed. However, unlike the cooling operation, the outdoor fan 36 is stopped so that melting of frost attached to the outdoor heat exchanger 23 is promoted.

<Cooling operation of power element by refrigerant jacket>
During the above operation, the power element 72 that generates heat at a high temperature is cooled by the refrigerant jacket 29. For example, during the cooling operation, the high-pressure liquid refrigerant radiated in the outdoor heat exchanger 23 flows through the refrigerant jacket 29 (here, the U-bent portion of the liquid refrigerant pipe 35). Therefore, the heat generated from the power element 72 is radiated to the high-pressure liquid refrigerant flowing through the refrigerant jacket 29 through the refrigerant cooling member 71 of the refrigerant jacket 29, and the power element 72 is cooled. During the heating operation, the refrigerant in the low-pressure gas-liquid two-phase state of the refrigeration cycle after radiating heat in the indoor heat exchanger 41 and being depressurized by the first expansion valve 24 is the refrigerant jacket 29 (here, the liquid refrigerant pipe 35 It flows through the U-bent part. Therefore, heat generated from the power element 72 is radiated to the low-pressure gas-liquid two-phase refrigerant flowing through the refrigerant jacket 29 through the refrigerant cooling member 71 of the refrigerant jacket 29, and the power element 72 is cooled. Note that the cooling operation of the power element 72 by the refrigerant jacket 29 is also performed by the control unit 8.

(3) Condensation protection control During the basic operation involving cooling of the power element 72 by the refrigerant jacket 29 as described above, the temperature conditions of the refrigerant flowing through the refrigerant jacket 29, the power element 72 such as the outside air temperature, and the refrigerant jacket 29 Depending on the ambient temperature conditions, condensation may occur in the power element 72 and its vicinity. Here, since the refrigerant circuit 10 is provided with the refrigerant jacket 29 that cools the power element 72 by the refrigerant flowing between the first expansion valve 24 and the outdoor heat exchanger 23 that functions as an evaporator of the refrigerant during heating operation. In addition, dew condensation in the power element 72 and its vicinity may be particularly noticeable. Specifically, the evaporator (outdoor heat exchanger 23 during the heating operation) side transiently from the operation stop such as when the heating operation starts after the operation stop or after the defrost operation or when the operation starts after the operation switching. When the refrigerant becomes insufficient, the pressure of the refrigerant flowing through the refrigerant jacket 29 (low pressure of the refrigeration cycle) may be excessively reduced. Such a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 causes a decrease in the temperature of the refrigerant jacket 29, which causes dew condensation in the power element 72 and the vicinity thereof.

  Here, with respect to the dew condensation in the power element 72 and the vicinity thereof caused by a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation from such operation stop or operation switching, conventional patent documents It is conceivable to apply control for increasing the rotational speed of the first compressor 21.

  However, in the conventional control for increasing the rotational speed of the compressor, the increase in the amount of heat generated by the power element 72 cannot follow the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29, and the refrigerant jacket 29 at the start of operation is There is a possibility that the dew condensation in the power element 72 and its vicinity due to a transient decrease in the pressure of the flowing refrigerant cannot be suppressed. Moreover, in the control which raises the rotation speed of the conventional compressor 21, since the flow volume of the refrigerant | coolant suck | inhaled by the compressor 21 from the evaporator (outdoor heat exchanger 23 at the time of heating operation) side will be increased, rather, There is even a possibility of causing a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation.

  As described above, the refrigerant circuit 10 is provided with the refrigerant jacket 29 that cools the power element 72 with the refrigerant flowing between the expansion valve (first expansion valve 24) and the evaporator (the outdoor heat exchanger 23 during heating operation). In the harmony device 1 (refrigeration device), it is necessary to be able to suppress dew condensation in the power element 72 and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation.

  Therefore, here, when the control unit 8 satisfies the dew condensation generation condition in which it is determined that dew condensation has occurred on the power element 72 or a peripheral member (the refrigerant jacket 29, the substrate 70, etc.) of the power element 72, the expansion is performed. Condensation protection control is performed to limit the opening degree of the valve (first expansion valve 24) to the large opening degree side.

  Next, control of the air conditioning apparatus 1 including dew condensation protection control will be described with reference to FIGS. Here, FIG. 5 is a flowchart of control of the air-conditioning apparatus 1 including condensation protection control. In addition, control of the air conditioning apparatus 1 including the dew condensation protection control demonstrated below is performed by the control part 8 similarly to said basic operation | movement.

  When starting operation from operation stop or operation switching (step ST7) (step ST1), the controller 8 starts the compressor 21 (step ST2). Thereafter, in step ST3, the control unit 8 determines whether or not a dew generation condition that determines that dew condensation has occurred on the power element 72 or a peripheral member of the power element 72 is satisfied. Whether or not the dew generation condition is satisfied depends on the temperature of the refrigerant jacket 29, the temperature of the power element 72, and / or the temperature of the refrigerant flowing through the evaporator (the outdoor heat exchanger 23 during heating operation). It is conceivable to make a determination based on the temperature of a component that causes condensation such as the temperature of the power element 72 and the evaporator (outdoor heat exchanger 23 during heating operation) or the equipment that causes the condensation.

  Here, if the temperature of the refrigerant jacket 29 (the power element 72 detected by the refrigerant cooling temperature sensor 51 and the representative temperature Tfin of the peripheral member of the power element 72) is lower than the jacket condensation generation temperature Tfin1, the condensation generation condition Judge that it satisfies. Further, the evaporation temperature of the refrigerant flowing through the evaporator (outdoor heat exchanger 23 during heating operation) (the refrigerant temperature Tm in the intermediate portion of the outdoor heat exchanger 23 detected by the outdoor heat exchanger intermediate temperature sensor 45) and the liquid side temperature. Condensation occurs when the temperature difference Tm−Tb with respect to (the refrigerant temperature Tb on the liquid side of the outdoor heat exchanger 23 detected by the outdoor heat exchange liquid side temperature sensor 46) exceeds the dew condensation generation temperature difference ΔT1. It is determined that the condition is satisfied. Here, the dew generation temperature Tfin1 may be a fixed temperature value, but the dew point temperature depends on the ambient temperature of the power element 72 and the refrigerant jacket 29 such as the outside air temperature (the temperature Ta of the outdoor air detected by the outside air temperature sensor 47). In consideration of the change, the temperature value may be varied depending on the ambient temperature of the power element 72 and the refrigerant jacket 29.

  Then, the control unit 8 does not satisfy the dew condensation generation condition in step ST3, that is, to the extent that a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation (low pressure in the refrigeration cycle) causes dew condensation. If it is determined that there is not, the process proceeds to step ST4. On the other hand, the controller 8 satisfies the condensation generation condition in step ST3, that is, a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation (low pressure in the refrigeration cycle) causes condensation. If it is determined that the degree is approximately, the process proceeds to step ST5.

  Next, in steps ST4 and ST5, the control unit 8 controls the opening degree of the expansion valve (first expansion valve 24) so that the superheat degree SHs of the refrigerant sucked into the compressor 21 becomes the target superheat degree SHst. (Superheat degree control), the temperature of the refrigerant discharged from the compressor 21 (the temperature Td of the high-pressure refrigerant of the refrigeration cycle discharged from the compressor 21 detected by the discharge temperature sensor 44) becomes the target discharge temperature Tdt. Some control such as control (discharge temperature control) is performed. Here, the superheat degree control includes the temperature of the refrigerant sucked into the compressor 21 (temperature Ts of the low-pressure refrigerant of the refrigeration cycle sucked into the compressor 21 detected by the suction temperature sensor 43) and the evaporator (heating operation). Sometimes the temperature difference Ts−Tm (= SHs) with the evaporation temperature of the refrigerant flowing in the outdoor heat exchanger 23) (the refrigerant temperature Tm in the intermediate portion of the outdoor heat exchanger 23 detected by the outdoor heat exchanger intermediate temperature sensor 45). Is to control the opening degree of the expansion valve (first expansion valve 24) so that the target superheat degree SHst becomes. In opening control of the expansion valve (first expansion valve 24) such as superheat degree control and discharge temperature control, the lower limit is the lower limit of the variable range of the opening of the expansion valve (first expansion valve 24). An opening degree MVm is set.

  In the case of step ST4, that is, when the dew condensation occurrence condition is not satisfied, the control unit 8 performs overheating while maintaining the lower limit opening MVm at the time when the lower limit opening MVm is shifted to step ST4. Opening control of the expansion valve (first expansion valve 24) such as degree control and discharge temperature control is performed. On the other hand, in the case of step ST5, that is, when the dew condensation occurrence condition is satisfied, the control unit 8 is a state in which the lower limit opening MVm is set larger than the lower limit opening set at the time of shifting to step ST5. Thus, the opening degree control of the expansion valve (first expansion valve 24) such as superheat degree control and discharge temperature control is performed. For example, the lower limit opening MVm is increased so that the flow rate of the refrigerant flowing through the expansion valve (first expansion valve 24) is increased by about 5% to 20%.

  Then, in the case of step ST5, that is, when the dew condensation generation condition is satisfied, the opening degree of the expansion valve (first expansion valve 24) performing opening degree control such as superheat degree control and discharge temperature control is set to the large opening side. Condensation protection control limited to And by performing this dew condensation protection control, the opening degree of the expansion valve (first expansion valve 24) can be forcibly increased. For this reason, here, even if the dew generation condition is satisfied by a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation (low pressure in the refrigeration cycle), the expansion valve (first expansion valve 24) The refrigerant existing on the upstream side of the refrigerant immediately flows into the refrigerant jacket 29 side, so that the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 can be alleviated and the temperature decrease of the refrigerant jacket 29 can be suppressed. Here, since the refrigerant circuit 10 is provided with a plurality of (here, two) expansion valves 24 and 26, the refrigerant existing on the upstream side of the expansion valve can quickly flow into the refrigerant jacket 29 side. In order to make it easier to control, in the refrigerant circuit 10, the first expansion valve 24 for reducing the pressure to the low pressure of the refrigeration cycle located on the upstream side of the refrigerant jacket 29 and closest to the refrigerant jacket 29 is set as the control target. It is preferable.

  Thereby, the dew condensation in the power element 72 and its vicinity resulting from the transient fall of the pressure of the refrigerant | coolant which flows through the refrigerant | coolant jacket 29 at the time of an operation start can be suppressed here. Further, here, condensation occurs based on the temperatures of the components that cause condensation, such as the temperature of the refrigerant jacket 29, the power element 72, and the evaporator (outdoor heat exchanger 23 during heating operation) and the equipment that causes the condensation. Since it is determined whether or not the condition is satisfied, it is possible to appropriately determine whether or not condensation has occurred on the power element 72 or a peripheral member of the power element 72. Here, as described above, as in the case where the dew condensation occurrence condition is not satisfied, the opening control of the expansion valve (first expansion valve 24) such as superheat degree control and discharge temperature control is continued, while the expansion valve Condensation protection control for limiting the opening of the (first expansion valve 24) to the large opening side can be performed. That is, as the dew condensation protection control, for example, it is conceivable to limit the opening degree of the expansion valve (first expansion valve 24) to the large opening degree side by forcibly increasing the opening degree from the current opening degree. Compared with control, it is preferable in that the opening degree control of the expansion valve (first expansion valve 24) such as superheat degree control and discharge temperature control can be continued.

  Then, the control unit 8 performs the dew condensation protection control in step ST5 until the dew condensation suppression condition is determined in which it is determined that no dew condensation occurs on the power element 72 or the peripheral member of the power element 72. That is, here, the dew condensation protection control is performed until the dew condensation in the power element 72 and the vicinity thereof due to the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation is suppressed. Whether or not the dew condensation suppression condition is satisfied is the same as the dew condensation occurrence condition, such as the temperature of the refrigerant jacket 29, the temperature of the power element 72, and / or the temperature of the refrigerant flowing through the evaporator (outdoor heat exchanger 23 during heating operation), etc. As described above, the determination is made based on the temperature of the component that causes condensation such as the temperature of the refrigerant jacket 29, the power element 72, and the evaporator (the outdoor heat exchanger 23 during heating operation) or the temperature of the device that causes the condensation. Can be considered.

  Here, when the temperature of the refrigerant jacket 29 (the power element 72 detected by the refrigerant cooling temperature sensor 51 and the representative temperature Tfin of the peripheral member of the power element 72) exceeds the jacket condensation suppression temperature Tfin2, the condensation suppression condition Judge that it satisfies. Further, the evaporation temperature of the refrigerant flowing through the evaporator (outdoor heat exchanger 23 during heating operation) (the refrigerant temperature Tm in the intermediate portion of the outdoor heat exchanger 23 detected by the outdoor heat exchanger intermediate temperature sensor 45) and the liquid side temperature. The determination is made based on whether or not the temperature difference Tm−Tb with respect to (the refrigerant temperature Tb on the liquid side of the outdoor heat exchanger 23 detected by the outdoor heat exchanger liquid temperature sensor 46) is less than the dew condensation suppression temperature difference ΔT2. Can do. In this case, in order to clearly detect that the dew condensation is suppressed, the dew condensation suppression temperature Tfin2 is set to a temperature value higher than the dew condensation generation temperature Tfin1, and the dew condensation suppression temperature difference ΔT2 is determined from the dew condensation generation temperature difference ΔT1. Is preferably set to a low temperature value. In addition, the dew condensation suppression temperature Tfin2 may be a fixed temperature value, but the dew point temperature varies depending on the ambient temperature of the power element 72 and the refrigerant jacket 29 such as the outside air temperature (the temperature Ta of the outdoor air detected by the outside air temperature sensor 47). Therefore, the temperature value may be varied depending on the ambient temperature of the power element 72 and the refrigerant jacket 29.

  Thereby, here, it is confirmed that the dew condensation in the power element 72 and its vicinity due to the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation is suppressed, and the dew condensation protection control is ended. it can. In addition, here, the dew condensation is suppressed based on the temperature of the component that causes dew condensation such as the temperature of the refrigerant jacket 29, the power element 72, and the evaporator (outdoor heat exchanger 23 during heating operation) or the device that causes dew condensation. Since it is determined whether or not the condition is satisfied, it is possible to appropriately determine whether or not the dew condensation on the power element 72 or the peripheral member of the power element 72 is suppressed.

(4) Modification 1
In the above embodiment, the control unit 8 performs the dew condensation protection control until the dew condensation suppression condition is satisfied when the dew condensation occurrence condition is satisfied by the processes of steps ST3, ST5, and ST6 (see FIG. 5). However, when the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation is excessive, the condensation in the power element 72 and its vicinity may not be suppressed even when the condensation protection control is performed. There is. Even in the case where the dew condensation protection control is continued in this case, the dew condensation on the power element 72 or the peripheral member of the power element 72 proceeds, causing a failure of the power element 72 or an electrical component near the power element 72. There is a fear.

  Therefore, here, even when the control unit 8 performs the dew condensation protection control, it is determined that the dew condensation suppression condition is not satisfied and it is determined that the dew condensation in the power element 72 or the peripheral member of the power element 72 is in progress. When the condition is satisfied, standby control for stopping the compressor 21 is performed.

  Next, the control of the air conditioning apparatus 1 including the dew condensation protection control and the standby control according to this modification will be described with reference to FIGS. Here, FIG. 6 is a flowchart of control of the air conditioner 1 including condensation protection control and standby control. The control of the air conditioner 1 including the dew condensation protection control and the standby control described below is also performed by the control unit 8 as in the above embodiment.

  When the condensation generation condition in step ST3 is satisfied and the condensation protection control in step ST5 is performed, the control unit 8 does not satisfy the condensation suppression condition in step ST6. In step ST8, the control unit 8 or the periphery of the power element 72 It is determined whether or not a standby condition for determining that condensation on the member is in progress is satisfied. Whether or not the standby condition is satisfied can be determined based on the time during which the condensation protection control in step ST5 continues in a state where the condensation suppression condition in step ST6 is not satisfied. For example, it can be determined based on whether or not the time after satisfying the dew condensation generation condition has reached the standby time t3. Here, as the standby condition, not only the standby time t3 but also the temperature of the refrigerant jacket 29 and / or the temperature of the power element 72, etc. A determination based on temperature may also be added.

  Here, the time during which the temperature of the refrigerant jacket 29 (the power element 72 detected by the refrigerant cooling temperature sensor 51 and the representative temperature Tfin of the peripheral members of the power element 72) is lower than the jacket standby temperature Tfin3 after satisfying the dew generation condition. Is determined based on whether or not the waiting time t3 has been reached. In this case, it is preferable to set the standby temperature Tfin3 to a temperature value lower than the condensation occurrence temperature Tfin1 and higher than the condensation suppression temperature Tfin2 in order to clearly detect that the condensation is advancing. The standby temperature Tfin3 may be a fixed temperature value, but the dew point temperature varies depending on the ambient temperature of the power element 72 and the refrigerant jacket 29 such as the outside air temperature (the temperature Ta of the outdoor air detected by the outside air temperature sensor 47). In view of this, the temperature value may be varied depending on the ambient temperature of the power element 72 and the refrigerant jacket 29.

  Then, the controller 8 satisfies the standby condition in step ST8, that is, the condensation due to the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation (low pressure of the refrigeration cycle) also by the condensation protection control. If it determines with progressing, it will transfer to the standby control of step ST10 through the process which checks the frequency | count of standby of step ST9. In this standby control, the compressor 21 is stopped after giving up to suppress the dew condensation on the power element 72 or the peripheral members of the power element 72 while continuing the operation.

  As a result, here, there is a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation to the extent that the dew condensation in the power element 72 or the peripheral member of the power element 72 proceeds even if the dew condensation protection control is performed. In the case of being excessive, priority can be given to preventing failure of the power element 72 and electric parts in the vicinity of the power element 72. Here, since it is determined whether or not the standby condition is satisfied based on the time during which the dew condensation protection control is continued in a state where the dew condensation suppression condition is not satisfied, the dew condensation on the power element 72 or a peripheral member of the power element 72 is determined. It is possible to appropriately determine whether or not the process is in progress.

  Here, since the distribution state of the refrigerant in the refrigerant circuit 10 changes before and after the operation including the dew condensation protection control, the degree of the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of the previous operation. In comparison with the above, there is a case where the degree of transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of the next operation is small.

  Therefore, here, the control unit 8 starts the compressor 21 after the standby control and determines again whether or not the dew condensation generation condition is satisfied. That is, after the standby control in step ST10, the control unit 8 activates the compressor 21 (step ST2), and determines again whether or not the condensation occurrence condition in step ST3 is satisfied. Then, when the dew generation condition is satisfied, the control unit 8 performs the dew condensation protection control in step ST5 again. Even if the dew condensation protection control is performed, the control unit 8 does not satisfy the dew condensation suppression condition in step ST6, and the standby condition in step ST8. When the condition is satisfied, the standby control in step ST20 is performed again.

  For this reason, when the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation is small enough not to satisfy the dew condensation generation condition, the process proceeds to step ST4, and the dew condensation protection control is performed as it is. Operation can be continued without performing. In this case, as described above, the condensation protection control is performed again when the condensation occurrence condition is satisfied. For this reason, when the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of the operation satisfies the dew condensation generation condition, the dew condensation protection control is performed when the dew condensation is suppressed to such an extent that the dew condensation control is suppressed. By performing the operation again, the dew condensation suppression condition is satisfied and the operation can be continued. In this case, as described above, even when the dew condensation protection control is performed, if the dew condensation suppression condition is not satisfied and the standby condition is satisfied, the standby control is performed again. Therefore, when the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation is not reduced to the extent that dew condensation is suppressed by the dew condensation protection control, standby control can be performed again. That is, a series of determinations including standby control and subsequent start-up of the compressor 21 until the transient drop in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation becomes small to the extent that dew condensation is suppressed by the dew condensation protection control. And control can be repeated.

  As a result, here, even if the transient drop in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation is excessive, the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation becomes a transient drop in pressure. Condensation in the power element 72 and in the vicinity thereof can be suppressed.

  However, when a series of determinations and controls (steps ST2, ST3, ST5, ST6, ST8, ST9, ST10) including standby control and subsequent activation of the compressor 21 are repeated many times, the refrigerant at the start of operation Other abnormalities such as excessive dew condensation in the power element 72 and its vicinity due to a transient drop in the pressure of the refrigerant flowing through the jacket 29, or failure of the expansion valve (first expansion valve 24) or sensors Factors need to be questioned.

  Therefore, here, when the number of times of standby control becomes equal to or greater than the upper limit number of times N3 in step ST9, the control unit 8 proceeds to a process of abnormally stopping without starting the compressor 21 in step ST11. That is, when the number of standby control times exceeds the upper limit standby frequency N3, the compressor 21 is not started by abnormally stopping.

  Thereby, here, various abnormalities including excessive dew condensation in the power element 72 and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation, such as by displaying an abnormal code together with an abnormal stop, etc. It is possible to inform that the inspection including the abnormal factor is necessary.

(5) Modification 2
In the above-described embodiment and Modification 1, the control unit 8 may perform start-up control in which the opening degree of the expansion valve (first expansion valve 24) is set to the start-up opening degree MVi at the start of operation. Here, starting control is control which sets the opening degree of an expansion valve (1st expansion valve 24) to starting opening degree MVi with the starting of the compressor 21. FIG. The starting opening degree MVi may be set to a constant opening degree or may be set to increase stepwise. And since the transient fall of the pressure of the refrigerant which flows through refrigerant jacket 29 at the time of an operation occurs also at the time of such starting control, starting opening degree MVi of the expansion valve (first expansion valve 24) at the time of starting control How to set the value affects the degree of transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation.

  Therefore, here, when the control unit 8 determines that the dew generation condition is satisfied, the dew condensation suppression start opening correction is performed to correct the start opening MVi so as to increase.

  Next, the control of the air conditioner 1 including the dew condensation protection control, the standby control, the start control, and the dew condensation suppression start opening correction according to this modification will be described with reference to FIGS. Here, FIG. 7 is a flowchart of control of the air conditioner 1 including condensation protection control, standby control, activation control, and condensation suppression activation opening degree correction. In addition, control of the air conditioning apparatus 1 including the dew condensation protection control, the standby control, the start control, and the dew condensation suppression start opening correction described below is also performed by the control unit 8 as in the above-described embodiment and modification 1. .

  Control part 8 performs starting control which sets the opening degree of an expansion valve (the 1st expansion valve 24) to starting opening degree MVi in Step ST12 with starting of compressor 21 (Step ST2). After that, when it is determined that the dew condensation generation condition is satisfied in step ST3, the control unit 8 performs dew condensation suppression start opening correction for correcting the start opening MVi so as to increase in steps ST14 and ST15. That is, when the operation that satisfies the dew condensation generation condition (step ST5) is performed, dew condensation occurs in the power element 72 and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation. Assuming that it is easy, the starting opening degree MVi is corrected so as to increase. For this reason, for example, when an operation determined to satisfy the dew condensation generation condition is performed, the startup opening MVi is corrected so as to increase, and the corrected startup opening MVi is corrected to the next startup control. (Step ST12). The startup opening MVi is corrected, for example, so that the opening is increased by about 5% to 15% with respect to the startup opening MVi before correction. On the other hand, when the control unit 8 determines that the dew condensation occurrence condition in step ST3 is not satisfied, unlike the case where the dew condensation occurrence condition is satisfied, the control unit 8 remains as it is without correcting the starting opening degree MVi. Maintain (step ST13).

  Then, not only in the case where the dew generation condition is satisfied, but also at the time of start-up control, the opening degree of the expansion valve (first expansion valve 24) can be increased, and upstream of the expansion valve (first expansion valve 24). It is possible to promptly cause the existing refrigerant to flow into the refrigerant jacket 29 side, alleviate the transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29, and suppress the temperature decrease of the refrigerant jacket 29.

  Thereby, here, at the start of operation including the start-up control, it is possible to contribute to suppression of dew condensation in the power element 72 and its vicinity due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29. Here, since standby control including steps ST8 and ST10 is also performed, the startup opening degree MVi corrected so as to increase in step ST15 is expanded at the subsequent startup of the compressor 21 (step ST2). The starting opening degree MVi of the valve (first expansion valve 24) is used. For this reason, at the time of starting the compressor 21 after standby control, a transient drop in the pressure of the refrigerant flowing through the refrigerant jacket 29 at the start of operation is likely to be reduced, and thus the compressor 21 is started after standby control. Even at this time, it is possible to contribute to suppression of dew condensation in the power element 72 and the vicinity thereof due to a transient decrease in the pressure of the refrigerant flowing through the refrigerant jacket 29.

(6) Modification 3
In the second modification, the control unit 8 corrects the starting opening degree MVi so as to increase when it is determined that the dew condensation generation condition is satisfied by the processes of steps ST3, ST14, and ST15 (see FIG. 7). Condensation suppression starting opening degree correction is performed. However, if the dew condensation suppression starting opening degree correction is performed, the starting opening degree MVi of the expansion valve (first expansion valve 24) becomes large. Therefore, if the starting opening degree MVi becomes too large, liquid refrigerant is sucked into the compressor 21. Liquid compression may occur.

  Therefore, here, when the control unit 8 satisfies the wetness generation condition in which it is determined that the refrigerant sucked into the compressor 21 is in a wet state that requires protection of the compressor 21, the starting opening degree MVi is satisfied. The wetness suppression start-up opening correction is performed so as to make the correction smaller.

  Next, the control of the air conditioner 1 including the dew condensation protection control, the standby control, the start control, the dew condensation suppression start opening correction and the wetness suppression start opening correction of the present modification will be described with reference to FIGS. . Here, FIG. 8 is a flowchart of control of the air conditioner 1 including condensation protection control, standby control, activation control condensation suppression activation opening correction, and wetness suppression activation opening correction. In addition, the control of the air conditioning apparatus 1 including the dew condensation protection control, standby control, start control, dew condensation suppression start opening correction, and wetness suppression start opening correction described below also includes the above embodiment and the first and second modifications. Similarly, it is performed by the control unit 8.

  After starting control in step ST12, the control unit 8 satisfies the wetness generation condition in which it is determined in step ST16 that the refrigerant sucked into the compressor 21 is in a wet state that requires protection of the compressor 21. Determine whether or not. Whether or not the wetness generation condition is satisfied can be determined based on the temperature or pressure indicating the operation state of the compressor 21. For example, it can be determined based on whether or not the superheat degree SHd of the refrigerant discharged from the compressor 21 is lower than the wetness generated superheat degree SHd4. Here, the superheat degree SHd includes the temperature of the refrigerant discharged from the compressor 21 (the temperature Td of the high-pressure refrigerant of the refrigeration cycle discharged from the compressor 21 detected by the discharge temperature sensor 44) and the radiator (heating operation). Sometimes the temperature difference Td-Th3 with the condensation temperature of the refrigerant flowing through the indoor heat exchanger 41) (the refrigerant temperature Th3 in the intermediate portion of the indoor heat exchanger 41 detected by the indoor heat exchanger intermediate temperature sensor 48).

  If the control unit 8 determines in step ST16 that the wetness generation condition is not satisfied, the control unit 8 proceeds to a determination process for determining whether or not the dew generation condition is satisfied in step ST3. On the other hand, if the control part 8 determines with satisfy | filling wetness generation conditions in step ST16, it will transfer to the process of step ST17, ST18.

  Next, in step ST17, the controller 8 performs superheat degree control and discharge temperature control in the state where the lower limit opening MVm is set at the time when the lower limit opening MVm is shifted to step ST17 as in step ST4. The degree of opening of the expansion valve (first expansion valve 24) is controlled. Thereafter, in step ST18, the control unit 8 performs wetness suppression start opening correction for correcting the start opening MVi so as to be small. That is, when the operation that satisfies the wetness generation condition is performed, it is considered that the refrigerant sucked into the compressor 21 is in a wet state that requires protection of the compressor 21, and the starting opening degree MVi is reduced. It is corrected as follows. For this reason, for example, when an operation determined to satisfy the wetness generation condition is performed, the startup opening degree MVi is corrected to be small, and the corrected startup opening degree MVi is corrected to the next startup control. (Step ST12). In addition, correction | amendment of starting opening degree MVi is correct | amended, for example so that an opening degree may become small about 5% -15% with respect to starting opening degree MVi before correction | amendment.

  Then, it is possible to prevent the refrigerant sucked into the compressor from entering a wet state that requires protection of the compressor, and it is possible to prevent the start opening from becoming too large due to the dew condensation suppression start opening correction.

  Accordingly, here, at the start of operation including the start-up control, the pressure of the refrigerant flowing through the refrigerant jacket 29 while preventing the refrigerant sucked into the compressor 21 from entering a wet state that requires protection of the compressor 21. It is possible to contribute to suppression of dew condensation in the power element 72 and the vicinity thereof due to the transient drop of the power. Here, since it is determined whether or not the wetness generation condition is satisfied based on the temperature and pressure indicating the operation state of the compressor 21, the refrigerant sucked into the compressor 21 needs to protect the compressor 21. It can be appropriately determined whether or not it is in a wet state.

(7) Other variations <A>
In the above-described embodiment and its modifications, the refrigerant jacket 29 employs a structure in which the U-bent portion of the liquid refrigerant pipe 35 is supported by the refrigerant cooling member 71, but is not limited thereto. Other structures can also be used.

<B>
In the above-described embodiment and its modifications, the refrigerant cooling temperature sensor 51 is provided in the refrigerant cooling member 71 of the refrigerant jacket 29, but is not limited thereto. For example, the power element 72 may be provided, or a temperature sensor (for example, the outdoor heat exchange liquid temperature sensor 46) that detects the temperature of the refrigerant flowing through the refrigerant jacket 29 may be substituted. Here, when the coolant cooling temperature sensor 51 is provided in the power element 72, the temperature of the power element 72 is compared with the determination value of the power element condensation generation temperature, the power element condensation suppression temperature, and the power element standby temperature. It may be determined whether or not the dew condensation generation condition, the dew condensation suppression condition, and the standby condition are satisfied. Further, when the outdoor heat exchanger side temperature sensor 46 is used as a substitute, the temperature Tb is compared with the dew condensation generation temperature, the dew condensation suppression temperature, and the standby temperature, which are the judgment values, to determine the dew condensation generation condition, the dew condensation suppression condition, What is necessary is just to determine whether conditions are satisfy | filled.

<C>
In the second and third modifications, the start control (step ST12), the dew condensation suppression start opening correction (steps ST14 and ST15), and the damp suppression start opening are compared with the control of the first modification including the dew protection control and the standby control. Although the example which added degree correction (step ST16, ST17, ST18) is demonstrated, it is not limited to this, with respect to control of said embodiment which does not include standby control, starting control and dew condensation suppression starting opening degree You may make it add correction | amendment and wetness suppression starting opening degree correction | amendment.

<D>
In the above embodiment and its modification (see FIG. 1), the refrigerant jacket 29 is provided between the first expansion valve 24 in the refrigerant circuit 10 and the outdoor heat exchanger 23 that functions as an evaporator during heating operation. However, it is not limited to this. For example, as shown in FIG. 9, a refrigerant jacket 29 may be provided between the second expansion valve in the refrigerant circuit 10 and an indoor heat exchanger 41 that functions as an evaporator during cooling operation. In this case, the control in the above embodiment and its modifications can be effectively utilized during the cooling operation.

<E>
In the above-described embodiment and its modification (see FIGS. 1 and 9), a plurality (two in FIGS. 1 and 9) of expansion valves 24 and 26 connected in series to the refrigerant circuit 10 are provided. However, the present invention is not limited to this. For example, as shown in FIG. 10, only one of the first expansion valve 24 and the second expansion valve 26 (here, the second expansion valve 26) may be provided. Even in this case, the control in the above-described embodiment and its modifications can be applied.

  The present invention can be widely applied to a refrigeration apparatus in which a refrigerant jacket for cooling a power element with a refrigerant flowing between an expansion valve and an evaporator is provided in a refrigerant circuit.

1 Refrigeration equipment (air conditioning equipment)
8 Control Unit 10 Refrigerant Circuit 21 Compressor 23 Outdoor Heat Exchanger (Evaporator, Radiator)
24, 26 Expansion valve 29 Refrigerant jacket 41 Indoor heat exchanger (heat radiator, evaporator)
72 Power element

JP 2010-25374 A

Claims (8)

A refrigerant circuit (10) configured by connecting a compressor (21), a radiator (41, 23), an expansion valve (24, 26), and an evaporator (23, 41), and a power element (72) And a control unit (8) for controlling the operation of the refrigerant, and the refrigerant that cools the power element by the refrigerant flowing between the expansion valve and the evaporator in the refrigerant circuit. In the refrigeration apparatus provided with the jacket (29),
The control unit is configured to prevent condensation when limiting a degree of opening of the expansion valve to a large degree of opening when satisfying a dew condensation generation condition that is determined to be dew condensation on the power element or a peripheral member of the power element. Do control,
Refrigeration equipment (1). The controller (8) limits the opening of the expansion valve to a large opening by increasing the lower limit opening of the expansion valve (24, 26) in the condensation protection control.
The refrigeration apparatus (1) according to claim 1. The control unit (8) performs the dew condensation protection control until a dew condensation suppression condition is determined to determine that dew condensation has not occurred in the power element (72) or a peripheral member of the power element.
The refrigeration apparatus (1) according to claim 1 or 2. Even if the said control part (8) performs the said dew condensation protection control, it determines with the said dew condensation suppression conditions being not satisfied, and the dew condensation in the peripheral member of the said power element (72) or the said power element is advancing. When the standby condition is satisfied, standby control is performed to stop the compressor (21).
The refrigeration apparatus (1) according to claim 3. The control unit (8) activates the compressor (21) after the standby control, determines again whether or not the dew condensation occurrence condition is satisfied,
The control unit performs the condensation protection control again when the condensation occurrence condition is satisfied, and does not satisfy the condensation suppression condition even when the condensation protection control is performed, and when the standby condition is satisfied, Perform standby control again,
The refrigeration apparatus (1) according to claim 4. The control unit (8) abnormally stops without starting the compressor (21) when the number of times of the standby control is equal to or greater than the upper limit number of standby times,
The refrigeration apparatus (1) according to claim 5. The control unit (8) performs start control for setting the opening of the expansion valve (24, 26) to the start opening at the start of operation,
The controller performs dew condensation suppression start opening correction for correcting the start opening to be increased when it is determined that the dew generation condition is satisfied.
The refrigeration apparatus (1) according to any one of claims 1 to 6. When the refrigerant sucked into the compressor (21) satisfies a wetness generation condition in which it is determined that the refrigerant is in a wet state that requires protection of the compressor, the controller (8) is activated and opened. Perform the dampening start-up opening correction to correct the degree to be small,
The refrigeration apparatus (1) according to claim 7.

Images