JP6370470B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus including an inverter heat dissipating section that cools an inverter apparatus used for driving a compressor.

  In recent years, for the purpose of improving the efficiency of partial load, a refrigeration apparatus that controls the operating frequency of a compressor by an inverter has been proposed. When AC power supplied from a commercial power source is converted and applied to the compressor, electrical losses in the rectifier circuit, smoothing capacitor, inverter circuit, and the like are converted into heat (hereinafter referred to as inverter heat generation).

  As a method of dissipating the inverter heat generation, a method of cooling the inverter heat radiating portion with a refrigerant has been proposed (for example, see Patent Documents 1 and 2). Patent Document 1 discloses a refrigeration apparatus provided with a cooling refrigerant flow path that branches from a refrigerant circulation flow path and communicates with a compressor main body via an inverter. Patent Document 2 discloses a method in which a bypass cooling circuit for cooling the inverter heat dissipating part is provided in the refrigerant circuit, and the amount of refrigerant passing through the inverter heat dissipating part is controlled based on the temperature of the inverter heat dissipating part. Yes.

Japanese Patent Laid-Open No. 2003-21406 JP 2008-57875 A

  As in the refrigeration apparatus of Patent Documents 1 and 2 above, when a refrigerant corresponding to the saturated gas temperature of the suction pressure is used for cooling the inverter radiating unit, or in the area affected by the suction gas temperature such as the vicinity of the motor frame In the case where the intake gas temperature is attached, during operation at a low intake gas temperature (for example, 0 ° C.), dew condensation may occur on the inverter frame and the function of the inverter circuit may be impaired.

  By the way, the method of cooling an inverter thermal radiation part using the refrigerant | coolant gas which passed the economizer (supercooler) can be considered. In this case, since the amount of refrigerant passing through the economizer is controlled based on the temperature of the inverter heat radiating section, the economizer cannot be effectively used when the amount of refrigerant that cools the inverter through the economizer is small, resulting in a decrease in capacity. is there.

  The present invention has been made in order to solve the above-described problems, and provides a refrigeration apparatus that suppresses a decrease in performance caused by preventing the use of an economizer while suppressing the occurrence of condensation in an inverter apparatus. With the goal.

  The refrigeration apparatus of the present invention includes a compressor that compresses the refrigerant, a condenser that dissipates and cools the refrigerant discharged from the compressor, an economizer that supercools the refrigerant that has flowed out of the condenser, and an overcooler in the economizer. A refrigerant circuit in which an expansion device that decompresses and expands the refrigerant, an evaporator that absorbs and evaporates the refrigerant decompressed and expanded in the expansion device by a refrigerant pipe, an inverter device that drives a compressor, and an inverter device An inverter cooling circuit that includes an inverter heat dissipation part that dissipates the generated heat, and a supercooling circuit that branches from between the economizer and the expansion device and forms a refrigerant flow path that flows into the compressor after flowing through the economizer and the inverter heat dissipation part A flow rate adjusting device that adjusts the refrigerant flow rate that is provided in the inverter cooling circuit and flows into the inverter heat dissipation unit, and the inverter heat dissipation unit Inverter temperature detection device that detects temperature as heat dissipation portion temperature, state detection portion that detects the state of refrigerant circulating in the economizer, heat dissipation portion temperature detected in the inverter temperature detection device and economizer detected in the state detection portion And a control device that controls the operation of the flow rate adjusting device based on the state of the circulating refrigerant, the control device determining whether or not the heat radiating portion temperature is within a target temperature range, and a state detection The superheat degree calculation unit that calculates the superheat degree of the refrigerant flowing through the economizer from the state of the refrigerant detected in the section, and when the temperature of the heat radiating part is within the target temperature range in the temperature determination part, the superheat degree calculation unit calculates The degree of opening of the flow control device is controlled so that the degree of superheat that has been achieved becomes the target degree of superheat, and the temperature of the heat radiating part deviates from the target temperature range in the temperature determination part. If it is determined that that, as the heat radiating portion temperature is within the target temperature range, and a opening control section for controlling the opening of the flow control device.

  According to the refrigeration apparatus of the present invention, when the heat dissipating part temperature is within the target temperature range, the opening degree of the flow rate adjusting device is controlled based on the degree of superheat, and when the heat dissipating part temperature is out of the target temperature range. Since the opening degree of the flow rate adjusting device is controlled based on the temperature of the heat radiating section, it is possible to suppress the occurrence of condensation during cooling of the inverter device while suppressing a decrease in capacity due to insufficient utilization of the economizer.

FIG. 3 is a refrigerant circuit diagram of the refrigeration apparatus according to Embodiment 1 of the present invention. It is a functional block diagram which shows an example of the control apparatus in the freezing apparatus of FIG. It is a flowchart which shows the operation example of the freezing apparatus of FIG. It is a refrigerant circuit figure which shows the freezing apparatus in Embodiment 2 of this invention. It is a refrigerant circuit figure which shows the freezing apparatus in Embodiment 3 of this invention. It is a flowchart which shows the operation example of the freezing apparatus of FIG.

Embodiment 1 FIG.
Hereinafter, embodiments of the refrigeration apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the refrigeration apparatus 1 includes a compressor 2, an oil separator 3, a condenser 4, an economizer 5, an expansion device 6, and an evaporator 7, which are connected by a refrigerant pipe to circulate the refrigerant. A refrigerant circuit 1A is configured.

  The compressor 2 consists of a screw compressor, for example, and compresses and discharges a refrigerant. The compressor 2 has a mechanical part 2a in which a compression element and an electric element are accommodated in a sealed container. Note that the type of the compressor 2 is not limited to a screw compressor, and may be, for example, a vane compressor, a rotary compressor, or a single-stage or multi-stage compressor. The compressor 2 is driven by the inverter device 20. The oil separator 3 separates the refrigerating machine oil contained in the refrigerant discharged from the compressor 2, and the separated refrigerating machine oil is returned to the compressor 2 again. The condenser 4 is a heat exchanger that radiates and cools the refrigerant discharged from the compressor 2 and separated in the oil separator 3.

  The economizer 5 is an inter-refrigerant heat exchanger that supercools the refrigerant that has flowed out of the condenser 4. The expansion device 6 is composed of, for example, an electronic expansion valve, and decompresses and expands the refrigerant subcooled in the economizer 5. The evaporator 7 is a heat exchanger that absorbs and evaporates the refrigerant expanded under reduced pressure in the expansion device 6.

  In addition, the refrigeration apparatus 1 includes an inverter device 20 that drives the compressor 2 and an inverter heat radiation unit 12 that radiates heat generated in the inverter device 20. The inverter device 20 and the inverter heat dissipating part 12 are integrally formed, and the inverter heat dissipating part 12 is provided integrally with the compressor 2. For example, in the compressor 2, the inverter heat radiating portion 12 is formed on the outer surface of the sealed container of the machine portion 2 a, and the heat generating components such as the inverter device 20 are disposed on the inverter heat radiating portion 12 together with the rectifier circuit and the smoothing capacitor. . The inverter heat dissipating unit 12 is formed of, for example, a heat sink in which a flow path is formed, and cools the inverter device 20 by circulating a refrigerant.

  The refrigeration apparatus 1 includes an inverter cooling circuit 10 that causes the refrigerant to flow through the inverter heat dissipating unit 12 and a flow rate adjusting device 11 that is provided in the inverter cooling circuit 10 and adjusts the flow rate of refrigerant flowing into the inverter heat dissipating unit 12. The inverter cooling circuit 10 includes a supercooling circuit 10A and a bypass cooling circuit 10B. The subcooling circuit 10 </ b> A branches from between the economizer 5 and the expansion device 6, and forms a refrigerant flow path that flows into the compressor 2 after flowing through the economizer 5 and the inverter heat radiation unit 12. And a part of refrigerant | coolant which goes to the expansion apparatus 6 from the economizer 5 branches, and flows into the inverter thermal radiation part 12, after decompressing with the 1st expansion valve 11A. By performing heat exchange with the refrigerant in the inverter heat radiating unit 12, the inverter heat radiating unit 12 is cooled, and the refrigerant gas is supplied to the intermediate pressure space of the compressor 2.

  The bypass cooling circuit 10 </ b> B branches from between the economizer 5 and the expansion device 6, and forms a refrigerant flow path that flows into the compressor 2 after flowing through the inverter heat radiating unit 12. The bypass cooling circuit 10B branches a part of the refrigerant from the economizer 5 toward the expansion device 6, depressurizes the second expansion valve 11B, and then flows the refrigerant into the inverter heat radiation unit 12. Then, the inverter heat radiating unit 12 is cooled by exchanging heat with the refrigerant, and merged with the refrigerant gas that has passed through the first expansion valve 11 </ b> A, and supplies the refrigerant gas to the intermediate pressure space of the compressor 2.

  That is, the inverter cooling circuit 10 includes a supercooling circuit 10A that causes the refrigerant to flow through the inverter heat radiation unit 12 and a bypass cooling circuit 10B. And since the inverter thermal radiation part 12 is cooled using the refrigerant | coolant (for example, refrigerant | coolant gas of 20-30 degreeC) which flows into an intermediate pressure space for cooling of the inverter thermal radiation part 12, generation | occurrence | production of the dew condensation to the inverter thermal radiation part 12 is suppressed. be able to. Moreover, the inverter cooling circuit 10 can make liquid cooling medium distribute | circulate also to the bypass cooling circuit 10B side, when cooling is insufficient in the inverter thermal radiation part 12 by 10 A of subcooling circuits, and can solve a cooling shortage.

  The flow rate adjusting device 11 is provided in the inverter cooling circuit 10 and adjusts the flow rate of the refrigerant flowing through the inverter heat radiating unit 12. The flow rate adjusting device 11 includes a first expansion valve 11A provided on the subcooling circuit 10A side, a second expansion valve 11B and an on-off valve 11C provided on the bypass cooling circuit 10B side. The first expansion valve 11 </ b> A is composed of, for example, an electronic expansion valve, and is provided between the economizer 5 and a branch point between the economizer 5 and the expansion device 6. By adjusting the opening degree of the first expansion valve 11A, the flow rate of the refrigerant flowing from the economizer 5 to the inverter heat radiating unit 12 is controlled on the supercooling circuit 10A side.

  The second expansion valve 11 </ b> B is composed of, for example, an electronic expansion valve, and is provided between the branch point between the economizer 5 and the expansion device 6 and the inverter heat radiating unit 12. The on-off valve 11C is provided between the branch point between the economizer 5 and the expansion device 6 and the second expansion valve 11B. The second expansion valve 11B and the on-off valve 11C constitute a bypass flow rate adjusting device that controls the refrigerant flow rate of the bypass cooling circuit 10B. In addition, although illustrated about the case where the 2nd expansion valve 11B and the on-off valve 11C are each provided, even if the on-off valve 11C is abbreviate | omitted using the electronic expansion valve which can be fully closed as the 2nd expansion valve 11B, it is. Good. By adjusting the opening degree of the second expansion valve 11B, the flow rate of the refrigerant flowing to the inverter heat radiating unit 12 is controlled on the bypass cooling circuit 10B side. Further, the flow of the refrigerant to the bypass cooling circuit 10B is controlled by controlling the opening / closing operation of the opening / closing valve 11C.

  An example of the operation of the refrigeration apparatus 1 will be described with reference to FIG. The refrigerant compressed in the compressor 2 is discharged from the compressor 2, separated into refrigerant gas and oil in the oil separator 3, and flows into the condenser 4. The refrigerant gas that has flowed into the condenser 4 is condensed into a liquid refrigerant, and is heat-cooled in the economizer 5 to be supercooled. The supercooled refrigerant is depressurized in the expansion device 6 and then sent to the evaporator 7. The refrigerant sent to the evaporator 7 exchanges heat with air, for example, becomes refrigerant gas, and flows into the compressor 2.

  Further, a part of the refrigerant traveling from the economizer 5 to the expansion device 6 branches to the inverter cooling circuit 10. The refrigerant branched to the supercooling circuit 10A side of the inverter cooling circuit 10 is depressurized in the first expansion valve 11A, and heat exchange between the refrigerants is performed in the economizer 5 to become refrigerant gas. Thereafter, the refrigerant cools the inverter device 20 in the inverter heat radiating section 12 and then flows into the intermediate pressure space of the compressor 2. Further, the refrigerant branched to the bypass cooling circuit 10B side of the inverter cooling circuit 10 passes through the second expansion valve 11B and the on-off valve 11C and cools the inverter heat radiating portion 12. Thereafter, the refrigerant merges with the refrigerant gas flowing through the subcooling circuit 10 </ b> A and is injected into the intermediate pressure space of the compressor 2.

  Operation | movement of the freezing apparatus 1 mentioned above is controlled in the control apparatus 40, and the control apparatus 40 controls based on the information detected by various sensors. Specifically, the refrigeration apparatus 1 includes a heat radiating portion temperature detection device 31, a state detection device (refrigerant temperature detection device 32a, intermediate pressure detection device 32b), a suction temperature detection device 33, a suction pressure detection device 34, and the like. .

  The heat dissipating part temperature detecting device 31 detects the temperature of the inverter heat dissipating part 12. The refrigerant temperature detection device 32 a and the intermediate pressure detection device 32 b function as a state detection device that detects the state of the refrigerant flowing through the inverter cooling circuit 10. The refrigerant temperature detection device 32 a detects the temperature of the refrigerant flowing through the economizer 5, and detects the temperature before flowing into the inverter heat radiating unit 12. The intermediate pressure detection device 32 b detects the pressure in the intermediate pressure chamber space in the middle of the compression unit of the compressor 2. The suction temperature detection device 33 detects the temperature of the refrigerant gas sucked into the compressor 2. The suction pressure detection device 34 detects the pressure of the refrigerant gas sucked into the compressor 2. Detection values detected by these detection devices are output to the control device 40.

  FIG. 2 is a functional block diagram illustrating an example of a control device in the refrigeration apparatus of FIG. The control device 40 in FIG. 2 is configured by hardware such as a circuit device that realizes the function, or an arithmetic device such as a microcomputer or a CPU, and software executed thereon. The control device 40 controls the flow rate of the refrigerant flowing through the inverter cooling circuit 10 based on the detection values detected by the heat radiating portion temperature detection device 31, the refrigerant temperature detection device 32a, and the intermediate pressure detection device 32b. 41, a superheat degree calculation unit 42, and an opening degree control unit 43 are provided.

  The temperature determination unit 41 determines whether or not the heat dissipation unit temperature Tr detected by the heat dissipation unit temperature detection device 31 is within the target temperature range. In the target temperature range, for example, the lower limit value Trl is set to 25 ° C. and the upper limit value Tru is set to 40 ° C. The temperature determination unit 41 determines whether the heat dissipation unit temperature Tr is within the target temperature range, exceeds the upper limit value Tru of the target temperature range, or falls below the lower limit value Trl of the target temperature range. The superheat degree calculation unit 42 calculates the superheat degree SH of the refrigerant gas flowing through the economizer 5 from the temperature detected by the refrigerant temperature detection device 32a and the pressure detected by the intermediate pressure detection device 32b.

  The opening degree control unit 43 controls the operation of the flow rate adjusting device 11 based on the determination result in the temperature determination unit 41. When the temperature determination unit 41 determines that the heat radiating unit temperature Tr is within the target temperature range, the opening degree control unit 43 sets the opening degree of the flow rate adjustment device 11 so that the superheat degree SH becomes the target superheat degree. Control. At this time, the opening degree control unit 43 allows the refrigerant on the supercooling circuit 10A side in the inverter cooling circuit 10 to flow and closes the on-off valve 11C on the bypass cooling circuit 10B side to the bypass cooling circuit 10B. Stop the inflow of refrigerant. Then, the opening degree control unit 43 controls the opening degree of the first expansion valve 11A on the supercooling circuit 10A side so that the superheat degree SH becomes the target superheat degree.

  On the other hand, when it is determined by the temperature determination unit 41 that the heat dissipation unit temperature Tr is lower than the lower limit value Trl (for example, 25 ° C.) of the target temperature range, it means that the inverter heat dissipation unit 12 is excessively cooled. The opening degree control unit 43 switches the control target from the superheat degree SH to the heat radiating part temperature Tr, and controls the opening degree of the first expansion valve 11A so that the heat radiating part temperature Tr is not less than the lower limit value Trl of the target temperature range.

  Further, the opening degree control unit 43 determines that the cooling of the inverter heat radiating unit 12 is insufficient when the temperature determining unit 41 determines that the heat radiating unit temperature Tr is larger than the upper limit value Tru of the target temperature range. . The opening degree control unit 43 switches the control target from the superheat degree SH to the heat radiating part temperature Tr, and controls the opening degree of the flow rate adjusting device 11 so that the heat radiating part temperature Tr falls within the target temperature range. At this time, the opening degree control unit 43 opens the on-off valve 11C and causes the refrigerant to flow through both the subcooling circuit 10A and the bypass cooling circuit 10B of the inverter cooling circuit 10. In this case, the temperature determination unit 41 changes the second upper limit value Trus (for example, 35 ° C.) lower than the upper limit value Tru of the initial target temperature range.

  When the temperature control unit 41 determines that the heat dissipation unit temperature Tr exceeds the changed second upper limit value Trus, the opening degree control unit 43 has the heat dissipation unit temperature Tr equal to or lower than the second upper limit value Trus. Until the opening of the second expansion valve 11B is increased. Thereafter, the opening degree control unit 43 maintains the opening degree of the second expansion valve 11B until it becomes smaller than the lower limit value Trl of the target temperature range even when the heat radiating portion temperature Tr becomes equal to or lower than the second upper limit value Trus. To control. After that, when the heat radiating portion temperature Tr becomes smaller than the lower limit value Trl of the target temperature range, the opening degree control unit 43 decreases the opening degree of the second expansion valve 11B. And when the opening degree of the 2nd expansion valve 11B becomes the minimum opening degree, the opening degree control part 43 closes the on-off valve 11C, and stops the distribution | circulation of the refrigerant | coolant of the bypass cooling circuit 10B.

  FIG. 3 is a flowchart showing an operation example of the refrigeration apparatus of FIG. Note that the process shown in the flowchart of FIG. 3 is performed at arbitrarily set control time intervals. First, based on the temperature detected by the refrigerant temperature detection device 32a and the intermediate pressure detected by the intermediate pressure detection device 32b, the superheat degree SH of the refrigerant gas at the gas temperature detection portion in the economizer 5 is calculated. The opening degree of the first expansion valve 11A is controlled so that the superheat degree SH becomes the target superheat degree (step ST11).

  Here, in the temperature determination unit 41, it is determined whether or not the heat dissipation part temperature Tr of the inverter heat dissipation part 12 is equal to or lower than the upper limit value Tru of the target temperature range (step ST12). When the heat radiating portion temperature Tr is equal to or lower than the upper limit value Tru of the target temperature range, it is determined that the temperature of the inverter device 20 is in an appropriate steady state, and when the heat radiating portion temperature Tr exceeds the upper limit value Tru of the target temperature range It is determined that the inverter device 20 is in the overheat operation state.

<Regarding the steady operation state (steps ST13 to ST16)>
When it is determined that the heat radiating portion temperature Tr is in a steady operation state that is equal to or lower than the upper limit value Tru of the target temperature range (YES in step ST12), the on-off valve 11C is closed and the circulation of the refrigerant in the bypass cooling circuit 10B is stopped ( Step ST13). Note that the operating state is maintained when the vehicle is already in the steady operating state. Thereafter, control device 40 determines whether or not heat radiating portion temperature Tr is equal to or higher than lower limit value Trl of the target temperature range (step ST14).

  When the heat radiating portion temperature Tr is equal to or higher than the lower limit value Trl of the target temperature range (YES in step ST14), the heat radiating portion temperature Tr is within the target temperature range and is determined to be in an appropriate state and the operation state is maintained. Is done. On the other hand, when the heat radiating portion temperature Tr is lower than the lower limit value Trl of the target temperature range (NO in step ST14), it is determined that the inverter device 20 is excessively cooled and condensation may occur. In this case, the control target of the first expansion valve 11A is changed from the superheat degree SH to the heat radiating portion temperature Tr (step ST15). Then, the opening degree of the first expansion valve 11A is controlled to be small until the heat radiating portion temperature Tr becomes equal to or higher than the lower limit value Trl of the target temperature range (steps ST14 to ST16). Thus, when the heat radiating portion temperature Tr is equal to or lower than the upper limit value Tru of the target temperature range, the control target is switched from the superheat degree SH to the heat radiating portion temperature Tr so that the cooling of the inverter heat radiating portion 12 does not become excessive. Can be cooled to.

<Superheated operation state>
When it is determined that the heat-radiating part temperature Tr is in the overheating operation state exceeding the upper limit value Tru of the target temperature range (NO in step ST12), the control target is changed from the superheat degree SH to the heat-radiating part temperature Tr. Further, the upper limit value Tru of the target temperature range is set to a second upper limit value Trus (for example, 35 ° C.) that is smaller than the initial value (step ST21). Then, the on-off valve 11C is opened (step ST22), and the refrigerant flows through both the supercooling circuit 10A and the bypass cooling circuit 10B. And it controls so that the opening degree of the 2nd expansion valve 11B may become large (step ST23). It is determined whether the heat radiating portion temperature Tr is equal to or lower than the second upper limit value Trus (step ST24), and the opening degree of the second expansion valve 11B is increased until the heat radiating portion temperature Tr becomes equal to or lower than the second upper limit value Trus (step ST24). ST23, ST24).

  On the other hand, when the heat radiating portion temperature Tr becomes equal to or lower than the second upper limit value Trus (YES in step ST24), it is determined whether the heat radiating portion temperature Tr is equal to or higher than the lower limit value Trl of the target temperature range (step ST25). When it is determined that the heat radiating portion temperature Tr is lower than the lower limit value Trl of the target temperature range (NO in step ST25), the inverter heat radiating portion 12 is overcooled, so the opening degree of the second expansion valve 11B is reduced (step ST25). , ST29).

  When the heat radiating portion temperature Tr is equal to or higher than the lower limit value Trl of the target temperature range (YES in step ST25), the opening degree of the second expansion valve 11B is maintained (step ST26). At this time, it is determined whether the opening of the second expansion valve 11B is the minimum opening (step ST27). When the opening degree of the second expansion valve 11B is not the minimum opening degree, the opening degree adjustment of the second expansion valve 11B described above is performed (step ST25 to step ST27). When the opening degree of the electronic expansion valve becomes the minimum opening degree (YES in step ST27), even if the on-off valve 11C is closed and the refrigerant does not flow to the bypass cooling circuit 10B side, the radiator temperature Tr is the upper limit of the target temperature range. It is determined that the value Tru has not been exceeded, and the on-off valve 11C is closed (step ST28). As mentioned above, the process of step ST21-step ST29 is implemented for every control time interval. In the case of the overheat operation state, the case where the opening degree of the second expansion valve 11B is adjusted is illustrated, but not only the opening degree of the second expansion valve 11B but also the opening degree on the first expansion valve 11A side. May also be adjusted.

  According to the first embodiment, when the heat radiating portion temperature Tr is within the target temperature range, the opening degree of the flow rate adjusting device 11 is controlled based on the degree of superheat SH, and the heat radiating portion temperature Tr is changed from the target temperature range. When it deviates, the opening degree of the flow control device 11 is controlled based on the heat radiation part temperature Tr. Thereby, generation | occurrence | production of the dew condensation at the time of cooling of the inverter apparatus 20 can be suppressed, aiming at suppression of the capability fall by insufficient utilization of the economizer 5. FIG. Moreover, by using the refrigerant | coolant which flows into intermediate pressure space for cooling of the inverter thermal radiation part 12, inhibition of the suction gas by the refrigerant | coolant which cooled the inverter apparatus 20 can be suppressed, and performance can be improved.

  In the steady operation state, by cooling the inverter heat radiating portion 12 using the refrigerant gas after passing through the economizer 5 flowing into the intermediate pressure space, the temperature difference between the outside air and the inverter heat radiating portion 12 is reduced, and condensation occurs. Can be suppressed. In the overheat operation state, the temperature of the inverter heat radiating unit 12 is controlled to be close to the upper limit value Tru of the target temperature range, so that the inverter heat radiating unit 12 is cooled without being overcooled. The temperature difference can be reduced and the occurrence of condensation can be suppressed.

  Further, when the heat radiating portion temperature Tr is in an overheated operation state exceeding the upper limit value Tru of the target temperature range, by further cooling the inverter heat radiating portion 12 using the liquid refrigerant on the bypass cooling circuit 10B side, Tr can be equal to or lower than the upper limit value Tru of the target temperature range and in the vicinity of the upper limit value Tru of the target temperature range. Therefore, excessive cooling of the inverter heat radiation part 12 can be suppressed, the temperature difference between the inverter heat radiation part 12 and the outside air can be reduced, and the occurrence of condensation can be suppressed.

  Further, even when the heat radiating portion temperature Tr is smaller than the lower limit value Trl of the target temperature range and the cooling is excessive, the control by the superheat degree SH is switched to the control by the heat radiating portion temperature Tr, and the dew condensation occurs. It is possible to avoid a state that tends to occur.

  Further, when the inverter cooling circuit 10 includes not only the supercooling circuit 10A but also the bypass cooling circuit 10B, the heat radiating portion temperature Tr can be quickly cooled to the target temperature range in the overheating operation state.

Embodiment 2. FIG.
FIG. 4 is a refrigerant circuit diagram illustrating a refrigeration apparatus according to Embodiment 2 of the present invention. The refrigeration apparatus 100 will be described with reference to FIG. In addition, in the refrigeration apparatus 100 of FIG. 4, the same code | symbol is attached | subjected to the site | part which has the same structure as the refrigeration apparatus 1 of FIG. 1, and the description is abbreviate | omitted. 4 differs from the refrigeration apparatus 1 of FIG. 1 in the attachment position of the refrigerant temperature detection device 132a.

  In the refrigeration apparatus 100 of FIG. 3, the refrigerant temperature detection device 132 a is attached at a position for detecting the temperature of the refrigerant that has flowed out of the inverter heat radiation unit 12. The outflow temperature sensor is provided at a position before joining the bypass cooling circuit 10B. And the superheat degree calculation part 42 calculates the superheat degree SH of refrigerant gas using the refrigerant temperature detected in the refrigerant temperature detection apparatus 132a. The opening degree control unit 43 controls the first expansion valve 11A so that the superheat degree SH becomes the target or the heat degree during steady operation.

  According to the second embodiment, as in the first embodiment, it is possible to suppress the occurrence of condensation during cooling of the inverter device 20 while suppressing a decrease in capacity due to insufficient utilization of the economizer 5. Furthermore, since the first expansion valve 11A is controlled based on the refrigerant temperature after the inverter heat radiating portion 12 is cooled, the range that can be operated in the control during the steady operation can be further expanded. In addition, since the amount of refrigerant that is liquid-injected during the overheating operation is also reduced, it is possible to suppress a decrease in performance in the overheating operation state.

Embodiment 3 FIG.
FIG. 5 is a refrigerant circuit diagram showing a refrigeration apparatus according to Embodiment 3 of the present invention. Refrigeration apparatus 200 will be described with reference to FIG. In the refrigerating apparatus 200 of FIG. 5, parts having the same configurations as those of the refrigerating apparatus 1 of FIG. The refrigeration apparatus 200 of FIG. 5 differs from the refrigeration apparatus 1 of FIG. 1 in the configuration of the inverter cooling circuit.

  The inverter cooling circuit 210 in FIG. 5 is configured by the supercooling circuit 10A without using the bypass cooling circuit 10B. Therefore, the opening degree control unit 43 of the control device 40 controls the opening degree of the first expansion valve 11 </ b> A that is the flow rate adjusting device 11.

  FIG. 6 is a flowchart illustrating a control example of the refrigeration apparatus according to Embodiment 1 of the present invention. Further, the process shown in the flowchart of FIG. 6 is performed at arbitrarily set control time intervals. In the flowchart of FIG. 6, the same reference numerals are given to the same process parts as those in the flowchart of FIG. The control is the same except that there is no step ST13 in the steady operation state, and steps ST31 to ST37, which are controls in the overheat operation state, will be described below.

<Overheat operation state>
In the opening degree control unit 43 of the control device 40, the control target of the first expansion valve 11A is changed from the superheat degree SH to the heat radiating unit temperature Tr (step ST31). Since the heat radiating portion temperature Tr is higher than the upper limit value Tru of the target temperature range, the opening degree of the first expansion valve 11A is controlled to be large (step ST32). Thereafter, it is determined whether or not the heat radiating portion temperature Tr has become equal to or lower than the upper limit value Tru of the target temperature range (step ST33). When it is determined that the heat radiating portion temperature Tr exceeds the upper limit value Tru of the target temperature range (NO in step ST33), the inverter heat radiating portion 12 is in a state of insufficient cooling, so the heat radiating portion temperature Tr is the upper limit of the target temperature range. Control is performed so that the opening degree of the first expansion valve 11A is increased until the value becomes equal to or less than the value Tru (steps ST32 and ST33).

  On the other hand, when it is determined that the heat radiating portion temperature Tr is equal to or lower than the upper limit value Tru of the target temperature range (YES in step ST33), it is determined whether the heat radiating portion temperature Tr is equal to or higher than the lower limit value Trl of the target temperature range (step ST34). ). If it is determined that the heat radiating portion temperature Tr is lower than the lower limit value Trl of the target temperature range (NO in step ST34), the inverter heat radiating portion 12 is cooled too much, and therefore the opening of the first expansion valve 11A is currently opened. It is controlled to be smaller than the degree (step ST37). Then, the opening degree of the first expansion valve 11A is controlled to be small until the heat radiating portion temperature Tr becomes equal to or higher than the lower limit value Trl of the target temperature range (steps ST34 and ST37).

  On the other hand, when the heat radiating portion temperature Tr is equal to or higher than the lower limit value Trl of the target temperature range (YES in step ST34), the degree of superheat SH is in the steady operation state in order to determine whether the steady operation state may be controlled. It is determined whether it is larger than the target superheat degree (step ST35). When the superheat degree SH is larger than the target superheat degree (YES in step ST35), it is determined that the economizer 5 cannot be utilized, and the control target of the first expansion valve 11A is the superheat degree in the steady operation state from the heat radiation part temperature Tr. It is changed to SH (step ST36). On the other hand, when the superheat degree SH is smaller than the control target superheat degree, the control based on the heat radiation part temperature Tr is continued (steps ST33 to ST35).

  According to the third embodiment, as in the first embodiment, the control target of the first expansion valve 11A is changed when the overheat operation state, that is, when the temperature of the inverter radiating unit 12 exceeds the upper limit value Tru of the target temperature range. Thus, the temperature of the inverter heat radiating unit 12 can be made equal to or lower than the upper limit value Tru of the target temperature range and in the vicinity of the upper limit value Tru of the target temperature range. Therefore, excessive cooling of the inverter heat radiation part 12 can be suppressed, and the temperature difference between the inverter heat radiation part 12 and the outside air can be reduced. Furthermore, since there is no cooling circuit by liquid injection, the refrigerant circuit and control can be simplified.

  1, 100, 200 Refrigeration equipment, 1A Refrigerant circuit, 2 Compressor, 2a Machine part, 3 Oil separator, 4 Condenser, 5 Economizer, 6 Expansion device, 7 Evaporator, 10, 210 Inverter cooling circuit, 10A Supercooling Circuit, 10B bypass cooling circuit, 11 flow rate adjusting device, 11A first expansion valve, 11B second expansion valve, 11C on-off valve, 12 inverter heat radiation part, 20 inverter device, 31 heat radiation part temperature detection device, 32a, 132a refrigerant temperature detection Device, 32b Intermediate pressure detection device, 33 Suction temperature detection device, 34 Suction pressure detection device, 40 Control device, 41 Temperature determination unit, 42 Superheat degree calculation unit, 43 Opening degree control unit, SH superheat degree, Tr Heat radiation unit temperature, Trl lower limit value, Tru upper limit value, Trus second upper limit value.

Claims (9)

A compressor that compresses the refrigerant; a condenser that dissipates and cools the refrigerant discharged from the compressor; an economizer that subcools the refrigerant that has flowed out of the condenser; and a vacuum that subcools the refrigerant that has been subcooled in the economizer A refrigerant circuit in which an expansion device that expands, and an evaporator that absorbs and evaporates the refrigerant expanded under reduced pressure in the expansion device are connected by a refrigerant pipe;
An inverter device for driving the compressor;
An inverter heat dissipating part for dissipating heat generated in the inverter device;
An inverter cooling circuit including a supercooling circuit that branches from between the economizer and the expansion device and forms a refrigerant flow path that flows into the compressor after flowing through the economizer and the inverter heat radiation unit;
A flow rate adjusting device which is provided in the inverter cooling circuit and adjusts the flow rate of the refrigerant flowing into the inverter heat radiation unit;
An inverter temperature detecting device for detecting the temperature of the inverter heat dissipating part as a heat dissipating part temperature;
A state detector that detects the state of the refrigerant circulating in the economizer;
A control device for controlling the operation of the flow rate adjusting device based on the temperature of the heat radiating portion detected in the inverter temperature detecting device and the state of the refrigerant flowing in the economizer detected in the state detecting portion;
The controller is
A temperature determination unit for determining whether or not the heat dissipation unit temperature is in a target temperature range;
A superheat degree calculation unit that calculates the superheat degree of the refrigerant flowing through the economizer from the state of the refrigerant detected in the state detection unit;
When the temperature of the heat radiating unit is within a target temperature range in the temperature determination unit, the opening degree of the flow rate adjustment device is controlled so that the degree of superheat calculated in the superheat degree calculation unit becomes the target superheat degree. When the temperature determining unit determines that the heat radiating unit temperature is out of the target temperature range, an opening degree for controlling the opening degree of the flow rate adjusting device so that the heat radiating unit temperature falls within the target temperature range. A control unit;
A refrigeration apparatus.   The said state detection part has an intermediate pressure detection apparatus which detects the intermediate pressure in the said compressor, and a refrigerant temperature detection apparatus which detects the temperature of the refrigerant | coolant which flows in into the said inverter thermal radiation part. Refrigeration equipment.   The refrigeration apparatus according to claim 1, wherein the state detection unit includes an intermediate pressure detection device that detects an intermediate pressure, and a refrigerant temperature detection device that detects the temperature of the refrigerant flowing out of the inverter heat dissipation unit.   The said control apparatus controls so that the opening degree of the said flow volume adjustment apparatus may be made small, when it determines with the said thermal radiation part temperature being smaller than the lower limit of a target temperature range. The refrigeration apparatus according to item 1.   The said opening degree control part is controlled to enlarge the opening degree of the said flow volume adjustment apparatus, when it determines with the said thermal radiation part temperature being larger than the upper limit of a target temperature range. The refrigeration apparatus of any one.   After the opening degree control unit performs control to increase the opening degree of the flow rate adjusting device, the temperature of the heat radiating unit becomes smaller than the upper limit value of the target temperature range, and the degree of superheat becomes larger than the target degree of superheat. The refrigeration apparatus according to claim 5, wherein the control target is changed from the heat radiating portion temperature to the superheat degree. The inverter cooling circuit includes a bypass cooling circuit that branches from between the economizer and the expansion device and is connected to the compressor via the inverter heat dissipation unit ,
The flow rate adjusting device is provided in the bypass cooling circuit, and includes a bypass flow rate adjusting device that adjusts a refrigerant flow rate flowing through the bypass cooling circuit,
The opening degree control unit controls the bypass flow rate adjusting device to an open state when the heat radiating unit temperature is larger than the upper limit value of the target temperature range, and the heat radiating unit temperature is equal to or lower than the upper limit value of the target temperature range. The refrigeration apparatus according to any one of claims 1 to 5, wherein the flow rate is adjusted by bringing the bypass flow rate adjusting device into a fully closed state.   The opening degree control unit closes the bypass flow rate adjusting device when the heat radiating unit temperature becomes lower than the lower limit value of the target temperature range after adjusting the flow rate with the bypass flow rate adjusting device opened. The refrigeration apparatus according to claim 7, which is put into a state.   The refrigeration apparatus according to any one of claims 1 to 8, wherein the inverter device and the inverter heat dissipating unit are disposed in a casing of the compressor.

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