WO2007091566A1 - Refrigerant heating device - Google Patents

Abstract

A refrigerant heating device with which super heat of a refrigerant is effectively suppressed and that can control the temperature of the refrigerant by itself without relying on an external temperature sensor. The refrigerant heating device (4) has at least one connection tube (11, 16), a heater (12), and at least one temperature sensor (13, 14, 15). The at least one connection tube (11, 16) is connected to the middle of a refrigerant circuit (10). The refrigerant circulates in the refrigerant circuit (10). The heater (12) heats the refrigerant flowing in the first connection tube (11) out of the connection tubes. The at least one temperature sensor (13, 14, 15) detects the temperature of the refrigerant flowing in the connection tube.

Description

 Specification

 Refrigerant heating device

 Technical field

 [0001] The present invention relates to a refrigerant heating apparatus for heating a refrigerant flowing in a refrigerant circuit.

 Background art

 [0002] As described in Patent Document 1, a refrigerant heating apparatus using an induction heater for heating a liquid refrigerant flowing through a refrigerant circuit of an air conditioner to improve heating capacity and defrosting capacity is disclosed. is there. This refrigerant heating device is installed between the outdoor unit and the indoor unit of the air conditioner. The outdoor unit has an outdoor heat exchanger, an expansion valve, a compressor, and a four-way switching valve. The indoor unit has indoor heat exchange. The refrigerant that has passed through the indoor heat exchange of the indoor unit is heated by the induction heater of the refrigerant heating device, and then is expanded by the expansion valve of the outdoor unit and flows into the outdoor heat exchanger.

 Patent Document 1: Japanese Patent Laid-Open No. 2002-5537

 Disclosure of the invention

 Problems to be solved by the invention

[0003] However, the refrigerant heating device described in Patent Document 1 is a force that uses information related to the temperature of the refrigerant that is necessary for controlling the operation of the induction heater. It depends on various temperature sensors outside the apparatus, for example, an outdoor unit or an outdoor temperature sensor provided in the indoor unit, an indoor temperature sensor, a refrigerant temperature sensor, or the like. Therefore, it is difficult to accurately measure the temperature of the refrigerant flowing in the vicinity of the refrigerant heating device, and it is difficult to suppress overheating of the refrigerant.

 In addition, since it depends on various temperature sensors outside the refrigerant heating device, there is a problem that the refrigerant heating device cannot control the temperature of the refrigerant alone.

 An object of the present invention is to provide a refrigerant heating apparatus that can effectively suppress overheating of the refrigerant and that can independently control the temperature of the refrigerant without depending on an external temperature sensor.

Means for solving the problem [0004] The refrigerant heating device of the first invention includes at least one connecting pipe, a heater, and at least one temperature sensor. At least one connecting pipe is connected in the middle of the refrigerant circuit. The refrigerant circulates in the refrigerant circuit. The heater heats the refrigerant flowing in the first connecting pipe among the connecting pipes. At least one temperature sensor detects the temperature of the refrigerant flowing through the connecting pipe.

 Here, since at least one temperature sensor for detecting the temperature of the refrigerant flowing through the first connection pipe in the middle of the refrigerant circuit is provided, the temperature of the refrigerant is not dependent on the temperature sensor of an external outdoor unit or the like. It is possible to detect accurately and suppress overheating of the refrigerant.

 [0005] A refrigerant heating device according to a second invention is the refrigerant heating device according to the first invention, and the temperature sensor includes a first temperature sensor and a second temperature sensor. The first temperature sensor is provided on the upstream side of the heater in the direction in which the refrigerant flows during heating. The second temperature sensor is provided on the downstream side of the heater in the direction in which the refrigerant flows during heating.

 Here, since the temperature sensor has the first temperature sensor and the second temperature sensor respectively provided on the upstream side and the downstream side of the heater, immediately after passing through the heater regardless of whether the refrigerant flows in the forward or reverse direction. It is possible to directly detect the temperature of the refrigerant. It is also possible to accurately detect the temperature difference of the refrigerant near the heater inlet / outlet.

 [0006] The refrigerant heating device of the third invention is the refrigerant heating device of the first invention or the second invention, and the temperature sensor further includes a third temperature sensor. The third temperature sensor is provided near the middle position in the axial direction of the heater.

 Here, since the temperature sensor further includes a third temperature sensor provided near the intermediate position in the axial direction of the heater, it is possible to detect local overheating of the refrigerant near the middle of the heater. is there. Thereby, it is possible to effectively suppress overheating of the refrigerant.

[0007] The refrigerant heating device of the fourth invention is the refrigerant heating device of any one of the first to third inventions, wherein the second connection pipe of the connection pipe is a refrigerant at a position different from the first connection pipe. Connected in the middle of the circuit. A gas refrigerant flows through the second connection pipe. The temperature sensor further includes a fourth temperature sensor. The fourth temperature sensor is provided in the second connection pipe. Here, the temperature of the gaseous refrigerant flowing through the second connecting pipe is measured by the fourth temperature sensor. It is possible to detect. As a result, the control unit can control the operation of the heater without receiving temperature information from the outside.

 [0008] A refrigerant heating device according to a fifth invention is the refrigerant heating device according to the first invention, further comprising a bridge circuit. The bridge circuit is connected to the first connecting pipe among the connecting pipes. The temperature sensor is provided either on the upstream side or the downstream side of the heater in the direction in which the refrigerant flows during heating.

 Here, the bridge circuit can control the direction of the refrigerant flowing through the first connection pipe so that it is in one direction regardless of heating and cooling. Therefore, it is possible to measure the refrigerant temperature immediately before or just after passing through the heater, both during cooling and during heating, by using a single temperature sensor provided on either the upstream side or the downstream side of the heater.

 [0009] A refrigerant heating device according to a sixth aspect of the present invention is the refrigerant heating device according to any one of the first to fifth aspects, wherein the temperature sensor is provided on the surface of the connecting pipe.

 Here, since the temperature sensor is provided on the surface of the first connecting pipe, the temperature of the refrigerant can be detected via the first connecting pipe.

[0010] A refrigerant heating device according to a seventh aspect of the present invention is the refrigerant heating device according to any of the first through fifth aspects, wherein the temperature sensor is provided inside the connecting pipe.

 Here, since the temperature sensor is provided inside the first connection pipe, the temperature of the refrigerant can be accurately detected by the temperature sensor being in direct contact with the refrigerant.

 [0011] A refrigerant heating device according to an eighth aspect of the present invention is the refrigerant heating device according to any one of the first through fifth aspects, further comprising a control unit. The control unit controls the operation of the heater based on the temperature of the refrigerant. The temperature of the refrigerant is detected by one or more temperature sensors. Here, since the controller further controls the operation of the heater based on the temperature of the refrigerant detected by one or more temperature sensors, the operation of the heater is controlled so as to suppress the overheating of the refrigerant. This can reduce the risk of refrigerant destruction.

[0012] The refrigerant heating device of the ninth invention is the refrigerant heating device of the eighth invention, and the control unit controls the output of the heater based on the temperature of the refrigerant detected by the temperature sensor. Here, since the control unit controls the output of the heater based on the temperature of the refrigerant detected by the temperature sensor, the output of the heater can be reduced before the refrigerant approaches its destruction temperature.

 [0013] The refrigerant heating device of the tenth invention is the refrigerant heating device of any of the first to ninth inventions, wherein the heater is an induction heating heater (hereinafter referred to as an IH heater). It is.

 Here, since the heater is an induction heater, the refrigerant can be rapidly heated.

 [0014] The refrigerant heating device of the eleventh invention is the refrigerant heating device of the tenth invention, wherein the heater has a coil. The temperature sensor is installed outside the coil.

 Here, since the temperature sensor is installed outside the coil of the heater, it is possible to avoid the generation of noise in the temperature sensor and its signal line due to the influence of electromagnetic waves generated by the coil force.

 [0015] The refrigerant heating device of the twelfth invention is the refrigerant heating device of the eighth invention, wherein the control unit detects that at least one temperature sensor detects a temperature equal to or higher than a predetermined first temperature. Reduce the heater output.

 Here, since the output of the heater is reduced when the control unit detects a temperature equal to or higher than the predetermined first temperature by at least one temperature sensor, the output of the heater is reduced until the refrigerant approaches its destruction temperature. It is possible to reduce.

 [0016] The refrigerant heating device of the thirteenth aspect of the invention is the refrigerant heating device of the twelfth aspect of the invention, wherein the control unit is configured when any one of the plurality of temperature sensors becomes a predetermined first temperature or higher. Reduce the heater output.

 Here, since the control unit reduces the output of the heater when any one of the plurality of temperature sensors becomes equal to or higher than the predetermined first temperature, the output of the heater is reduced until the refrigerant approaches the breakdown temperature. It is possible to reduce. In particular, by using a plurality of temperature sensors, it is possible to improve the reliability of temperature detection and to reliably suppress local overheating of the refrigerant.

[0017] The refrigerant heating device of the fourteenth invention is the refrigerant heating device of the twelfth invention, wherein the first temperature is 8 0 to 100 ° C.

 Here, since the first temperature is 80 to 100 ° C., the control unit can accurately perform control to reduce the output of the heater when the temperature of the refrigerant approaches its destruction temperature.

[0018] The refrigerant heating device of the fifteenth invention is the refrigerant heating device of the twelfth invention, wherein the first temperature is a temperature obtained by adding 20 to 40 ° C to the temperature of the refrigerant before heating by the heater. .

 Here, the first temperature is a temperature obtained by adding 20 to 40 ° C to the temperature of the refrigerant before heating by the heater, so it is possible to accurately control the output of the heater based on the temperature of the refrigerant It is.

 [0019] The refrigerant heating device of the sixteenth aspect of the invention is the refrigerant heating device of the twelfth aspect of the invention, wherein the first temperature is a temperature obtained by adding 20 to 40 ° C to the amount of change of the refrigerant temperature per predetermined time. is there.

 Here, since the first temperature is a temperature obtained by adding 20 to 40 ° C to the amount of change in the refrigerant temperature every predetermined time, control to reduce the heater output based on the refrigerant temperature is accurately performed. It is possible.

 [0020] The refrigerant heating device of the seventeenth aspect of the invention is the refrigerant heating device of the eighth aspect of the invention, wherein the control unit detects that at least one temperature sensor detects a temperature equal to or higher than a predetermined second temperature. Stop the heater.

 Here, since the heater stops when at least one temperature sensor detects a temperature equal to or higher than the predetermined second temperature, the heater is surely stopped before the refrigerant approaches its destruction temperature. Is possible.

[0021] The refrigerant heating device of the eighteenth aspect of the invention is the refrigerant heating device of the seventeenth aspect of the invention, wherein the control unit is configured when any one of the plurality of temperature sensors becomes equal to or higher than a predetermined second temperature. Stop the heater.

Here, the controller stops the heater when any one of the plurality of temperature sensors reaches a predetermined second temperature or higher, so that the heater is stopped before the refrigerant approaches its destruction temperature. Is possible. In particular, by using a plurality of temperature sensors, the reliability of temperature detection can be improved and local overheating of the refrigerant can be reliably suppressed. [0022] The refrigerant heating device of the nineteenth invention is the refrigerant heating device of the seventeenth invention, wherein the second temperature is 140-160. C.

 Here, since the second temperature is 140 to 160 ° C., the control unit can accurately perform control to stop the output of the heater when the temperature of the refrigerant approaches its destruction temperature.

[0023] A refrigerant heating device according to a twentieth aspect of the invention is the refrigerant heating device according to the eighth aspect of the invention, wherein the control unit detects the temperature when at least one temperature sensor detects a temperature equal to or higher than a predetermined first temperature. The output is controlled in a stepwise manner so that the heater is stopped when a temperature equal to or higher than a predetermined second temperature is detected.

 Here, the control unit lowers the output of the heater when at least one temperature sensor detects a temperature equal to or higher than a predetermined first temperature, and the control unit detects when a temperature equal to or higher than a predetermined second temperature is detected. Since the heater is controlled step by step so as to stop the heater, it is possible to reliably suppress overheating of the refrigerant.

 [0024] The refrigerant heating device of the twenty-first invention is the refrigerant heating device of the eighth invention, wherein the control unit detects that at least one temperature sensor detects a transient increase of 40 to 60 ° C. Stop the heater.

 Here, the control unit stops the heater when at least one temperature sensor detects a transient rise of 40 to 60 ° C, so the control to stop the heater based on the refrigerant temperature is ensured. Can be done.

[0025] A refrigerant heating device according to a twenty-second invention is the refrigerant heating device according to the eighth invention, wherein the control unit determines that the temperature of the refrigerant circuit has increased by 40 to 60 ° C when the defrost operation is performed. Stops the heater when the sensor detects it.

 Here, the controller stops the heater when at least one temperature sensor detects that the refrigerant circuit has risen by 40 to 60 ° C during defrost operation, so the refrigerant is overheated during defrost operation. Can be reliably suppressed.

[0026] A refrigerant heating device according to a twenty-third invention is the refrigerant heating device according to the eighth invention, in which the control unit is based on the temperature of the refrigerant flowing in the connection pipe detected by one or more temperature sensors. Switching between start and stop. Here, since the control unit can switch and control the start and stop of the heater based on the temperature of the refrigerant flowing in the first connection pipe detected by the plurality of temperature sensors, the refrigerant heating device is externally connected. It is possible to control the starting and stopping of the heater independently without receiving the temperature information.

 The invention's effect

 According to the first invention, the temperature of the refrigerant can be accurately detected without depending on a temperature sensor such as an external outdoor unit, and overheating of the refrigerant can be suppressed.

[0028] According to the second invention, it is possible to directly detect the temperature of the refrigerant immediately after passing through the heater, regardless of whether the refrigerant flows in the forward or reverse direction. In addition, it is possible to accurately detect the temperature difference of the refrigerant in the vicinity of the heater entrance.

[0029] According to the third invention, local overheating of the refrigerant in the vicinity of the middle of the heater can be detected. Thereby, the overheating of a refrigerant | coolant can be suppressed effectively.

[0030] According to the fourth invention, the temperature of the gaseous refrigerant flowing through the second connecting pipe can be detected by the fourth temperature sensor. Thereby, the operation control of the heater can be performed without the control unit receiving temperature information from the outside.

[0031] According to the fifth aspect of the invention, the temperature of the refrigerant immediately before or just after passing through the heater is measured both during cooling and during heating by one temperature sensor provided on either the upstream side or the downstream side of the heater. Can be measured.

[0032] According to the sixth aspect of the invention, the temperature of the refrigerant can be detected via the first connection pipe.

[0033] According to the seventh invention, the temperature of the refrigerant can be accurately detected by the temperature sensor directly contacting the refrigerant.

[0034] According to the eighth aspect of the present invention, the risk of the refrigerant being destroyed can be reduced by controlling the operation of the heater so as to suppress overheating of the refrigerant.

[0035] According to the ninth aspect, the output of the heater can be reduced until the refrigerant approaches its destruction temperature.

 [0036] According to the tenth invention, the refrigerant can be heated quickly.

[0037] According to the eleventh aspect, it is possible to avoid the generation of noise in the temperature sensor and its signal line due to the influence of the electromagnetic wave generated by the coil force. [0038] According to the twelfth invention, the output of the heater can be reduced until the refrigerant approaches its destruction temperature.

 [0039] According to the thirteenth invention, the output of the heater can be reduced before the refrigerant approaches its destruction temperature. In particular, by using a plurality of temperature sensors, the reliability of temperature detection is improved and local overheating of the refrigerant can be reliably suppressed.

 [0040] According to the fourteenth aspect, when the temperature of the refrigerant approaches its destruction temperature, the control unit can accurately perform control to reduce the output of the heater.

 [0041] According to the fifteenth aspect of the present invention, it is possible to accurately perform control for reducing the output of the heater based on the temperature of the refrigerant.

 [0042] According to the sixteenth aspect of the present invention, it is possible to accurately perform control for reducing the output of the heater based on the temperature of the refrigerant.

 [0043] According to the seventeenth aspect, the heater can be reliably stopped before the refrigerant approaches its destruction temperature.

 [0044] According to the eighteenth invention, it is possible to stop the heater S before the refrigerant approaches its destruction temperature. In particular, by using a plurality of temperature sensors, the reliability of temperature detection is improved and local overheating of the refrigerant can be reliably suppressed.

 [0045] According to the nineteenth invention, when the temperature of the refrigerant approaches the destruction temperature, the control unit can accurately perform control to stop the output of the heater.

 [0046] According to the twentieth invention, overheating of the refrigerant can be reliably suppressed.

 [0047] According to the twenty-first aspect, it is possible to reliably perform control to stop the heater based on the temperature of the refrigerant.

 [0048] According to the twenty-second aspect, overheating of the refrigerant during the defrosting operation can be reliably suppressed.

 [0049] According to the twenty-third aspect, the refrigerant heating device can perform control such as starting and stopping the heater independently without receiving temperature information from the outside.

 Brief Description of Drawings

 FIG. 1 is a configuration diagram of an air conditioner including a refrigerant heating device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a refrigerant circuit of the air conditioner of FIG. FIG. 3 is an internal configuration diagram of the refrigerant heating device of FIG.

 [FIG. 4] (a) Arrangement of first temperature sensor and second temperature sensor in FIG. 2, (b) Graph of refrigerant temperature during heating, and (c) Graph of refrigerant temperature during defrost.

[FIG. 5] (a) Arrangement of the third temperature sensor of FIG. 2, (b) A graph showing the distribution of heat generation density of the IH heater, and (c) A graph of the refrigerant temperature during heating.

圆 6] (a) graph of change in refrigerant temperature over time and (b) graph of change in heater capacity over time in the two-stage temperature control of the refrigerant heating device of FIG.

7) (a) Graph of refrigerant temperature with time and (b) Graph of heater capacity with time in multi-stage temperature control, which is a modification of the first embodiment.

[8] Internal configuration diagram of the refrigerant heating apparatus according to the second embodiment of the present invention.

9] Internal configuration diagram of the refrigerant heating apparatus according to the third embodiment of the present invention.

Explanation of symbols

 1 Air conditioner

2 Outdoor unit

3 Indoor unit

 4, 104, 204 Refrigerant heating device

 5 Refrigerant piping

 6 Refrigerant piping

 10 Refrigerant circuit

 11 First connection pipe

 12 IH heater

 13 First temperature sensor

 14 Second temperature sensor

 15 Third temperature sensor

 16 Second connection pipe

 17 Control unit

 18 AC power supply

19 Switch 21 4th temperature sensor

 22 Compressor

 23 Outdoor heat exchanger

 24 fans

 25 Four-way selector valve

 26 Solenoid expansion valve

 27 Indoor heat exchanger

 28 Cross flow fan

 BEST MODE FOR CARRYING OUT THE INVENTION

 [First Embodiment]

 As shown in FIGS. 1 and 2, the air conditioner 1 includes an outdoor unit 2, an indoor unit 3, and a refrigerant calorie heat device 4. The outdoor unit 2 is connected to the refrigerant heating device 4 and the indoor unit 3 installed inside the indoor space R via the refrigerant pipe 5 and the refrigerant pipe 6. As shown in FIG. 2, the refrigerant in the liquid state flows through the refrigerant pipe 5, and the refrigerant in the gas state flows through the refrigerant pipe 6. The refrigerant circuit 10 includes refrigerant pipes 5 and 6, an outdoor unit 2 (specifically, an electromagnetic expansion valve 26, an outdoor heat exchanger 23, a compressor 22 and a four-way switching valve 25), and an indoor unit 3 (components). Specifically, it is composed of the indoor heat exchanger 27) and the refrigerant heating device 4 (specifically, the first connecting pipe 11, the IH heater 12, and the second connecting pipe 16). FIG. 2 shows the refrigerant circuit 10 in the heating operation state. The heating operation will be described in detail later.

 <Configuration of Refrigerant Heating Device 4>

 2 and 3, the refrigerant heating device 4 includes a first connection pipe 11, an IH heater 12, a second connection pipe 16, a first temperature sensor 13, a second temperature sensor 14, The third temperature sensor 15 includes an ff¾ control, an AC power source 18, a switch 19, and four connection rods 20a, 20b, 20c, and 20d.

 The first connection pipe 11 is connected in the middle of the refrigerant circuit 10. Specifically, the first connecting pipe 11 is closer to the indoor heat exchange than the outdoor heat exchange in the refrigerant pipe 5 through which the liquid refrigerant flows between the outdoor heat exchanger 23 and the indoor heat exchanger 27. Get connected!

The eaves heater 12 is a heater that heats the refrigerant flowing inside the first connection pipe 11. Coffee The coil 12 has a coil 12a and a cylindrical member 12b. The coil 12a is wound around the outer surface of the cylindrical member 12b made of a heat insulating material. The IH heater 12 uses induction heating to heat an iron core (not shown) inside the first connection pipe 11, thereby heating the refrigerant flowing inside the first connection pipe 11. The IH heater 12 can quickly heat the refrigerant, and can improve the heating capacity and the defrosting capacity.

The AC power supply 18 is an AC power supply for the IH heater 12 and is a so-called inverter power supply that performs inverter control.

 The second connection pipe 16 is connected to the refrigerant pipe 6 (liquid refrigerant side) opposite to the refrigerant pipe 5 (liquid refrigerant side) to which the first connection pipe 11 in indoor heat exchange is connected. .

 The first connection part 20a and the second connection part 20b are provided at both ends of the first connection pipe 11, and connect the first connection pipe 11 and the refrigerant pipe 5. The third connection part 20c and the fourth connection part 20d are provided at both ends of the second connection pipe 16, and connect the second connection pipe 16 and the refrigerant pipe 6. The first to fourth connection parts 20a to 20d also have a force such as a combination of a male screw part formed on the end of the refrigerant pipe 5 or 6 and a flare nut.

 The first temperature sensor 13, the second temperature sensor 14, and the third temperature sensor 15 detect the temperature of the refrigerant flowing through the first connection pipe 11. This makes it possible to reliably detect the temperature of the refrigerant without depending on a temperature sensor such as the external outdoor unit 2, and to suppress overheating of the refrigerant.

[0055] The first temperature sensor 13 is provided on the surface of the first connection pipe 11 on the upstream side of the heater 12 by V in the direction in which the refrigerant flows during heating (see the flow direction F1 in FIG. 3). .

 The second temperature sensor 14 is provided on the surface of the first connection pipe 11 on the downstream side of the heater 12 in the direction in which the refrigerant flows during heating.

 The first temperature sensor 13 and the second temperature sensor 14 can directly detect the temperature of the refrigerant immediately after passing through the IH heater 12, and the temperature difference of the refrigerant in the vicinity of the inlet / outlet of the IH heater 12 can be assured. Can be detected.

Specifically, the first temperature sensor 13 and the second temperature sensor 14 provided in the vicinity of the inlet / outlet of the IH heater 12 shown in FIG. 4 (a) flow in the first connection pipe 11 as follows. The temperature of the refrigerant can be detected. In the case of the flow direction F1 of the refrigerant during heating, as shown in FIG. 4 (b), the refrigerant temperature near the inlet of the IH heater 12 can be detected by the first temperature sensor 13, and the IH can be detected by the second temperature sensor 14. The refrigerant temperature (about 40 ° C) near the outlet of the heater 12 can be detected. In the case of the refrigerant flow direction F2 during reverse cycle defrost, as shown in FIG. 4 (c), the second temperature sensor 14 can detect the refrigerant temperature near the inlet of the IH heater 12 and the first temperature. Sensor 13 can detect the refrigerant temperature (around 40 ° C) near the outlet of IH heater 12.

 The first temperature sensor 13 and the second temperature sensor 14 are installed outside the coil 12a of the IH heater 12. For this reason, it is possible to avoid the occurrence of noise in the first temperature sensor 13 and the second temperature sensor 14 and their signal lines due to the influence of the electromagnetic waves generated from the coil 12a.

 The third temperature sensor 15 is provided near the intermediate position in the axial direction of the IH heater 12. The third temperature sensor 15 can reliably detect that the refrigerant is locally overheated near the middle of the IH heater 12, and can effectively suppress overheating of the refrigerant. Become.

 That is, the temperature of the refrigerant flowing inside the first connecting pipe 11 can be detected by the third temperature sensor 15 provided near the middle of the IH heater 12 shown in FIG. 5 (a) as follows. For example, in the case of the flow direction F1 of the refrigerant during heating, as shown in FIG. 5 (b), the IH heater 12 has a high heat generation density near the middle. As shown in FIG. 4, the temperature of the refrigerant is locally high near the middle. Therefore, the third temperature sensor 15 provided near the middle position of the IH heater 12 detects the refrigerant temperature near the middle of the IH heater 12, thereby reliably detecting that the refrigerant is locally overheated. It becomes possible to do.

[0057] For example, if the refrigerant is locally heated to 140 ° C, a part of the refrigerant may be destroyed, but the third temperature sensor 15 causes the refrigerant to locally approach 140 ° C. It is possible to reliably detect that In addition, when the refrigerant locally rises to near 140 ° C, the surface of the first connection pipe 11 is near 160 ° C, so the third temperature sensor 15 is connected to the first connection using this correspondence. Detect the temperature force of the surface of the tube 11 near S160 ° C This makes it possible to detect that the refrigerant has locally reached 140 ° C.

 The first temperature sensor 13, the second temperature sensor 14, and the third temperature sensor 15 described above are provided on the surface of the first connection pipe 11. These temperature sensors 13, 14, and 15 measure the surface temperature of the first connecting pipe 11, so that it is possible to indirectly detect the temperature of the refrigerant inside the first connecting pipe 11 corresponding to the surface temperature. It is. Note that the correspondence between the surface temperature of the first connecting pipe 11 and the refrigerant temperature is obtained in advance by experiments or the like, and the map of the correspondence between the surface temperature and the refrigerant temperature is a storage unit of the control unit 17. Remember me! RU

The control unit 17 controls the operation of the IH heater 12 based on the refrigerant temperature detected by the one or more temperature sensors 13, 14, 15. The operation control of the IH heater 12 is performed by controlling the power supply of 18 AC power and the ONZOFF control of the switch 19. As a result, it is possible to reduce the risk of refrigerant destruction by suppressing overheating of the IH heater 12.

 The control unit 17 controls the output of the IH heater 12 based on the refrigerant temperature detected by the first to third temperature sensors 13, 14, 15. Specifically, the control unit 17 controls the power supply from the AC power source 18 based on the temperature of the refrigerant detected by the first to third temperature sensors 13, 14, 15, so that the IH heater 12 Control the output of.

 Configuration of outdoor unit 2>

 As shown in FIG. 2, the outdoor unit 2 includes a compressor 22 that compresses refrigerant, an outdoor heat exchanger 23 that performs heat exchange between the refrigerant and outdoor air, and air that passes through the outdoor heat exchanger 23. An outdoor fan 24 that generates a flow, a four-way switching valve 25 that reverses the circulation direction of the refrigerant, and an electromagnetic expansion valve 26 are provided. The outdoor unit 2 can reverse the refrigerant flow in the refrigerant circuit 10 by switching the four-way switching valve 25.

[0059] <Configuration of indoor unit 3>

As shown in FIG. 2, the indoor unit 3 includes an indoor heat exchanger 27 and a cross flow fan 28 that generates an air flow passing through the indoor heat exchanger 27. The indoor heat exchanger 27 can perform both condensation and evaporation of the refrigerant by reversing the flow direction of the refrigerant inside the refrigerant circuit 10 by the four-way switching valve 25. This allows indoor heat exchange Can perform heating and cooling by exchanging heat between the refrigerant supplied from the outdoor unit 2 through the refrigerant pipes 5 and 6 and the room air.

 <Explanation of temperature control>

 The air conditioner 1 configured as described above can perform a cooling operation, a heating operation, a forward cycle differential opening operation, and a reverse cycle defrosting operation. The explanation of the operation in each mode will be described in detail in the subsequent items.

Here, the refrigerant heating device 4 operates the IH heater 12 to heat the refrigerant during the heating operation, the forward cycle defrost operation, and the reverse cycle defrost operation. At this time, the control unit 17 performs the following temperature control of the refrigerant in order to surely perform the output control and the ON ZOFF control of the IH heater 12 so as to suppress overheating of the refrigerant.

 (About output control of IH heater 12)

 The control unit 17 reduces the output of the IH heater 12 when any one of the plurality of temperature sensors 13, 14, and 15 becomes equal to or higher than a predetermined first temperature T1. Note that when at least one temperature sensor 13, 14, 15 detects a temperature equal to or higher than the predetermined first temperature T1, the output of the IH heater 12 may be reduced. Therefore, the temperature sensors 13, 14, 15 Only one of these forces may be left and the other temperature sensors may be omitted.

[0061] The first temperature T1 is 80 to: L00 ° C. The first temperature T1 is set as a 80-100 ° C force first temperature T1, which is a temperature range close to the breakdown temperature of the refrigerant.

 (On / off control of IH heater 12! /)

 The control unit 17 stops the IH heater 12 when any one of the plurality of temperature sensors (13, 14, 15) becomes equal to or higher than a predetermined second temperature T2. If at least one temperature sensor 13, 14, 15 detects a temperature equal to or higher than the predetermined second temperature T2, the IH heater 12 may be stopped. You can leave only one of them and omit the other temperature sensor! /.

 The second temperature T2 is 140 to 160 ° C. The second temperature T2 is higher than the first temperature T1 and is in a temperature range very close to the breakdown temperature of the refrigerant. 140 to 160 ° C Force Set as the second temperature T2.

[0062] Further, the control unit 17 includes the first connection pipes detected by the plurality of temperature sensors 13, 14, 15. It is also possible to control the start of the IH heater 12 when it is detected based on the temperature of the refrigerant flowing through the refrigerant 11 that the refrigerant temperature has dropped to the second temperature T2 or less just by stopping the IH heater 12. Therefore, the control unit 17 can also switch and control the start and stop of the IH heater 12.

 (Two-step control of IH heater 12)

 The control unit 17 of the first embodiment reduces the output of the IH heater 12 when the at least one temperature sensor 13, 14, 15 detects a temperature equal to or higher than the predetermined first temperature T1, and sets the predetermined second temperature. Step by step to stop the IH heater 12 when a temperature above T2 is detected.

 For example, as shown in FIG. 6 (a), when any one of the plurality of temperature sensors 13, 14, 15 detects that the temperature of the refrigerant has reached the first temperature T1, the control unit 17 As shown in FIG. 6B, the output of the IH heater 12 is reduced to a predetermined heater capacity. Further, when the temperature sensors 13, 14, and 15 detect that the refrigerant temperature has reached the second temperature T2, the control unit 17 stops the IH heater 12 as shown in FIG. 6 (b). Then, set the heater capacity to 0. As described above, the output of the IH heater 12 can be controlled in two stages based on the refrigerant temperature. It is also possible to set multiple first temperatures T1, which serve as a reference for reducing the heater output, and perform multi-step control of three or more steps.

 <Heating operation of air conditioner 1>

During the heating operation, the four-way selector valve 25 is maintained in the state indicated by the solid line in FIG. 2, and the refrigerant circulates counterclockwise in the refrigerant circuit 10 shown in FIG. First, the gas refrigerant is compressed by the compressor 22 and then brought to a high temperature and high pressure state. Next, the high-temperature and high-pressure gas refrigerant flows into the indoor heat exchanger 27 of the indoor unit 3 through the four-way switching valve 25, the second connection pipe 16, and the refrigerant pipe 6, and condenses by exchanging heat with the indoor air. Liquid. At this time, the indoor air heated by the condensation of the refrigerant is blown out into the indoor space R by the cross flow fan 28 to heat the indoor space R. Next, the refrigerant that has become liquid in the indoor heat exchange flows into the first connection pipe 11 of the refrigerant heating device 4 through the refrigerant pipe 5 and is heated by the IH heater 12. The refrigerant heated by the IH heater 12 expands by passing through the electromagnetic expansion valve 26 of the outdoor unit 2 and is depressurized to a predetermined low pressure. After that, outdoor heat exchange of outdoor unit 2 In the vessel 23, the expanded refrigerant evaporates by exchanging heat with outdoor air. At this time, an air flow passing through the outdoor heat exchanger 23 is generated by the outdoor fan 24. The refrigerant evaporated and evaporated in the outdoor heat exchanger 23 is sucked into the compressor 22 through the four-way switching valve 25.

 [0064] <Cooling operation of air conditioner 1>

 On the other hand, during the cooling operation, the four-way switching valve 25 is held in a state indicated by a broken line in FIG. 2, and the refrigerant circulates clockwise through the refrigerant circuit 10 shown in FIG. The high-temperature and high-pressure gas refrigerant discharged from the compressor 22 flows into the outdoor heat exchanger 23 through the four-way switching valve 25, and exchanges heat with the outdoor air that is forcibly sent to the outdoor heat exchanger by the outdoor fan 24. To condense and liquefy. The liquefied refrigerant is decompressed to a predetermined low pressure by the outdoor expansion valve 13 and flows into the indoor unit 3 through the refrigerant pipe 5 on the liquid refrigerant side. In the indoor unit 3, the refrigerant evaporates by exchanging heat with indoor air in the indoor heat exchanger 27. Then, the indoor air cooled by the evaporation of the refrigerant is blown out into the indoor space R by the cross flow fan 28 to cool the indoor space R. The refrigerant evaporated and vaporized in the indoor heat exchanger 27 returns to the outdoor unit 2 through the refrigerant pipe 6 on the gas refrigerant side, and is sucked into the compressor 22.

 [0065] <Reverse cycle defrost operation of air conditioner 1>

 When the outdoor air temperature is less than 0 ° C, frost may form on the outer surface of the outdoor heat exchanger 23 of the outdoor unit 2. In such a case, the air conditioner 1 performs a reverse cycle defrost operation for defrosting. During the reverse cycle defrost operation, basically, as in the cooling operation described above, the four-way switching valve 25 is maintained in the state indicated by the broken line in FIG. 2, and the refrigerant rotates the refrigerant circuit 10 shown in FIG. It circulates to. The high-temperature and high-pressure gas refrigerant discharged from the compressor 22 flows into the outdoor heat exchanger 23 via the four-way switching valve 25 and condenses and liquefies.

 During this reverse cycle defrost operation, the frost adhering to the outer surface of the outdoor heat exchanger 23 can be melted by the heat of condensation of the refrigerant. At this time, the outdoor fan 24 is stopped. On the other hand, on the indoor unit 3 side, the refrigerant is evaporated by the indoor heat exchanger 27 while the cross flow fan 28 is stopped. The refrigerant evaporated and vaporized in the indoor heat exchanger 27 returns to the outdoor unit 2 through the refrigerant pipe 6 on the gas refrigerant side, and is sucked into the compressor 22.

At this time, in the refrigerant heating device 4, the liquid flowing through the first connection pipe 11 connected to the refrigerant pipe 5 By heating the refrigerant with the IH heater 12, it is possible to improve the defrosting capacity and shorten the defrost time.

 The control unit 17 stops the IH heater 12 when at least one temperature sensor 13, 14, 15 detects that the refrigerant circuit 10 has risen by 40 to 60 ° C when performing reverse cycle defrost operation. Is pretty.

 <Direct cycle defrost operation of air conditioner 1>

 When the outdoor air is at a temperature of 0 ° C or higher, the air conditioner 1 performs a positive cycle defrost operation in which the indoor space R is heated while defrosting. During the forward cycle defrost operation, basically, as in the heating operation described above, the four-way switching valve 25 is maintained in the state indicated by the solid line in FIG. 2, and the refrigerant counterclocks the refrigerant circuit 10 shown in FIG. Circulate around.

[0067] In the forward cycle defrost operation, the compressor 22 is operated with a reduced capacity. The high-temperature and high-pressure gas refrigerant discharged from the compressor 22 flows into the indoor heat exchanger 27 through the four-way switching valve 25, and the cross-flow fan 28 is operated while condensing and liquid. Heat space R.

 The condensed and liquefied refrigerant is heated by the IH heater 12 of the refrigerant heating device 4 and then flows to the outdoor heat exchanger 23. When the heated refrigerant flows into the outdoor heat exchanger 23, it is possible to melt frost adhering to the outer surface of the outdoor heat exchanger. At this time, the outdoor fan 24 is operating.

 The control unit 17 stops the IH heater 12 when at least one of the temperature sensors 13, 14, 15 detects that the refrigerant circuit 10 has risen by 40 to 60 ° C when performing the positive cycle defrost operation. Is pretty.

<Features of First Embodiment>

 (1)

 The refrigerant heating device 4 of the first embodiment includes, in addition to the IH heater 12 for refrigerant heating, at least one temperature sensor 13 that detects the temperature of the refrigerant flowing through the first connection pipe 11 in the refrigerant circuit 10. Since 14 and 15 are provided, it is possible to reliably detect the temperature of the refrigerant without depending on a temperature sensor of an external outdoor unit or the like, and to suppress overheating of the refrigerant.

(2) In the refrigerant heating device 4 of the first embodiment, the temperature sensor has the first temperature sensor 13 and the second temperature sensor 14 provided on the upstream side and the downstream side of the IH heater 12, respectively. It is possible to directly detect the temperature of the refrigerant immediately after passing through the IH heater 12 regardless of whether the direction is forward or reverse, that is, when heating or reverse cycle defrosting. In addition, it is possible to reliably detect the temperature difference of the refrigerant near the entrance / exit of the IH heater 12.

[0069] (3)

 In the refrigerant heating device 4 of the first embodiment, the temperature sensor further includes the third temperature sensor 15 provided in the vicinity of the intermediate position in the axial direction of the IH heater 12. It is possible to detect local overheating. Thereby, it is possible to effectively suppress the overheating of the cooling medium.

 (Four)

 In the refrigerant heating device 4 of the first embodiment, since the temperature sensors 13, 14, and 15 are provided on the surface of the first connection pipe 11, it is possible to detect the temperature of the refrigerant through the first connection pipe 11. Noh.

 (Five)

 The refrigerant heating device 4 of the first embodiment is a control that controls the operation of the IH heater 12 based on the temperature of the refrigerant detected by one or more temperature sensors 13, 14, 15. Since the portion 17 is further provided, it is possible to reduce the risk of refrigerant destruction by controlling the operation of the IH heater 12 so as to suppress overheating of the refrigerant.

[0070] (6)

 In the refrigerant heating device 4 of the first embodiment, since the control unit 17 controls the output of the IH heater 12 based on the temperature of the refrigerant detected by the temperature sensors 13, 14, 15, the refrigerant approaches its destruction temperature. By this, the output of the IH heater 12 can be reduced.

 (7)

 In the first embodiment, since the IH heater 12 is employed as the heater for heating the refrigerant, the refrigerant can be heated quickly.

(8) In the refrigerant heating device 4 of the first embodiment, the first temperature sensor 13 and the second temperature sensor 14 are installed outside the coil 12a of the IH heater 12! Therefore, due to the influence of electromagnetic waves generated from the coil 12a, It is possible to avoid the generation of noise in the temperature sensors 13 and 14 and their signal lines.

[0071] (9)

 In the refrigerant heating device 4 of the first embodiment, when the control unit 17 detects at least one temperature sensor 13, 14, 15 detects a temperature equal to or higher than the predetermined first temperature T1, the output of the IH heater 12 is reduced. Therefore, the output of the IH heater 12 can be reduced before the refrigerant approaches its destruction temperature.

 (Ten)

 In the refrigerant heating device 4 of the first embodiment, the control unit 17 reduces the output of the IH heater 12 when any one of the plurality of temperature sensors 13, 14, 15 reaches a predetermined first temperature T1 or higher. Therefore, the output of the IH heater 12 can be reduced before the refrigerant approaches its destruction temperature. In particular, the reliability of temperature detection is improved by using multiple temperature sensors 13, 14, and 15, and local overheating of the refrigerant near the middle or downstream side of the IH heater 12 is reliably suppressed. Is possible.

[0072] (10)

 In the refrigerant heating device 4 of the first embodiment, since the first temperature T1 is 80 to: LOO ° C., the control unit 17 outputs the output of the IH heater 12 when the refrigerant temperature approaches its destruction temperature. It is possible to accurately perform the control to be lowered.

 (11)

 In the refrigerant heating device 4 of the first embodiment, the control unit 17 stops the IH heater 12 when at least one temperature sensor 13, 14, 15 detects a temperature equal to or higher than a predetermined second temperature T2. Therefore, the IH heater 12 can be accurately stopped before the refrigerant approaches its destruction temperature.

 (12)

In the refrigerant heating device 4 of the first embodiment, the control unit 17 stops the IH heater 12 when any one of the plurality of temperature sensors 13, 14, and 15 becomes equal to or higher than the predetermined second temperature T2. Therefore, the IH heater 12 can be stopped before the refrigerant approaches its destruction temperature. In particular, the use of multiple temperature sensors 13, 14, and 15 improves the reliability of temperature detection and reliably suppresses local overheating of the refrigerant near the middle or downstream of the IH heater 12. It is possible.

[0073] (13)

 In the refrigerant heating device 4 of the first embodiment, since the second temperature T2 is 140 to 160 ° C., the control unit 17 outputs the output of the IH heater 12 when the temperature of the refrigerant approaches its destruction temperature. It is possible to accurately perform the control to stop.

 (14)

 In the refrigerant heating device 4 of the first embodiment, the control unit 17 reduces the output of the IH heater 12 when at least one temperature sensor 13, 14, 15 detects a temperature equal to or higher than the predetermined first temperature T1. Since the IH heater 12 is controlled stepwise when a temperature equal to or higher than the predetermined second temperature T2 is detected, overheating of the refrigerant can be reliably suppressed.

 (15)

 In the refrigerant heating device 4 of the first embodiment, the control unit 17 indicates that the refrigerant circuit 10 has risen by 40 to 60 ° C. when performing the defrost operation in the forward cycle or the reverse cycle, and at least one temperature sensor 13, Since the IH heater 12 is stopped when 14 and 15 are detected, it is possible to reliably suppress overheating of the refrigerant during the defrost operation.

[0074] (16)

 In the refrigerant heating device 4 of the first embodiment, the control unit 17 is based on the temperature of the refrigerant flowing through the first connection pipe 11 detected by the plurality of temperature sensors 13, 14, 15 and! Therefore, the refrigerant heating device 4 can control the start and stop of the IH heater 12 independently without receiving temperature information from the outside. Is possible.

 <Modification of the first embodiment>

 (A)

In the first embodiment, the force that the temperature sensors 13, 14, and 15 are provided on the surface of the first connection pipe 11. The present invention is not limited to this, and the temperature sensors 13, 14, and 15 are connected to the first connection pipe 11 in the first connection. It may be provided inside the tube 11. In this case, the temperature of the refrigerant can be detected with high accuracy by the temperature sensor being in direct contact with the refrigerant.

 [0075] (B)

 In the first embodiment, the first temperature T1 is a force that presets a predetermined numerical range based on the type of refrigerant. The present invention is not limited to this, and the first temperature T1 is the IH heater. A temperature obtained by adding a predetermined temperature rise of 20 to 40 ° C to the temperature of the refrigerant before heating by 12 may be adopted, and in this case as well, the output of the IH heater 12 is based on the temperature of the refrigerant. It is possible to accurately control the reduction.

 (C)

 Furthermore, as another modification, a temperature obtained by adding 20 to 40 ° C to the amount of change in the refrigerant temperature every predetermined time may be adopted as the first temperature T1, in this case also based on the refrigerant temperature. Therefore, it is possible to accurately control the output of the IH heater 12 to be lowered.

[0076] (D)

 In the first embodiment, a predetermined numerical range based on the type of refrigerant is set in advance as the second temperature T2 that serves as a reference for stopping the IH heater 12, but the present invention is not limited to this. The control unit 17 may stop the IH heater 12 when at least one temperature sensor 13, 14, 15 detects a transient increase of 40 to 60 ° C. In this case as well, it is possible to accurately perform control to stop the output of the IH heater 12 based on the refrigerant temperature.

 For example, as shown in FIG. 7 (a), while the refrigerant is being heated by the IH heater 12, the temperature of the refrigerant gradually rises, but at least one of the facts that it has risen by a predetermined temperature ΔΤ. Each time the temperature sensors 13, 14, and 15 are detected, the control unit 17 controls the output of the IH heater 12 to be reduced by a predetermined heater capacity as shown in FIG. It is also possible to control the IH heater 12 to stop when at least one temperature sensor 13, 14, 15 detects that the second temperature T240-60 ° C has risen transiently.

[0077] (E)

In the first embodiment, the force at which the first temperature sensor 13 and the second temperature sensor 14 are provided on the upstream side and the downstream side of the IH heater 12, respectively. If a temperature sensor is provided on one of the flow sides, the temperature of the refrigerant flowing through the IH heater 12 can be accurately detected.

 [Second Embodiment]

 In the first embodiment, the force provided with the temperature sensors 13, 14, 15 in the first connecting pipe 11 through which the liquid refrigerant flows. The present invention is not limited to this. The temperature sensor detects the temperature of the refrigerant. The arrangement can be changed as appropriate.

 As shown in FIG. 8, the refrigerant heating device 104 of the second embodiment, instead of providing the third temperature sensor 15 near the middle of the IH heater 12 as compared to the refrigerant heating device 4 of the first embodiment, The other difference is that the fourth temperature sensor 21 is provided, and other configurations are the same as those of the refrigerant calorie heat device 4 of the first embodiment.

 That is, the refrigerant heating device 104 includes a first connection pipe 11, an IH heater 12, a second connection pipe 16, a first temperature sensor 13, a second temperature sensor 14, a fourth temperature sensor 21, and a control unit. 17 / AC power supply 18 / Switch 19/4 connections 20a, 20b, 20c and 20d! The fourth temperature sensor 21 is provided on the surface of the second connection pipe 16 through which the gaseous refrigerant flows. The fourth temperature sensor 21 provided on the surface of the second connection pipe 16 can detect the refrigerant evaporation temperature of the refrigerant gas.

 <Features of the second embodiment>

 (1)

 In the refrigerant heating device 104 of the second embodiment, the fourth temperature sensor 21 can detect the refrigerant evaporation temperature of the refrigerant gas flowing through the second connection pipe 16. As a result, the controller 17 can control the operation of the IH heater 12 without receiving temperature information from the outside.

 (2)

Further, the refrigerant heating device 104 of the second embodiment is similar to the refrigerant heating device 4 of the first embodiment, in addition to the IH heater 12 for refrigerant heating, the first connection pipe 11 and the second Since it has at least one temperature sensor 13, 14, 21 that detects the temperature of the refrigerant flowing through the connecting pipe 16, it can accurately detect the temperature of the refrigerant without depending on the temperature sensor of an external outdoor unit. And overheating of the refrigerant can be suppressed. [0079] (3)

 Further, similarly to the refrigerant heating device 4 of the first embodiment, the refrigerant heating device 104 of the second embodiment includes the first temperature sensor 13 and the temperature sensor provided on the upstream side and the downstream side of the IH heater 12, respectively. Since the second temperature sensor 14 is provided, it is possible to directly detect the temperature of the refrigerant immediately after passing through the IH heater 12 during both heating and cooling. Further, it is possible to accurately detect the temperature difference of the refrigerant in the vicinity of the inlet / outlet of the IH heater 12.

 (Four)

 Further, in the refrigerant heating device 104 of the second embodiment, similarly to the refrigerant heating device 4 of the first embodiment, the temperature sensors 13, 14, and 21 are provided on the surface of the first connection pipe 11 or the second connection pipe 16. Therefore, the temperature of the refrigerant can be detected via the first connection pipe 11 or the second connection pipe 16.

[0080] (5)

 Further, the refrigerant heating device 104 of the second embodiment is based on the temperature of the refrigerant detected by one or a plurality of temperature sensors 13, 14, 21 in the same manner as the refrigerant heating device 4 of the first embodiment. Since the controller 17 for controlling the operation of the IH heater 12 is further provided, it is possible to reduce the possibility of the refrigerant being destroyed by controlling the operation of the IH heater 12 so as to suppress the overheating of the refrigerant. .

 (6)

 Further, in the refrigerant heating device 104 of the second embodiment, similarly to the refrigerant heating device 4 of the first embodiment, the control unit 17 is based on the temperature of the refrigerant detected by the temperature sensors 13, 14, 21. Since the output of the IH heater 12 is controlled, the output of the IH heater 12 can be reduced before the refrigerant approaches its destruction temperature.

[0081] (7)

 Further, similar to the refrigerant heating device 4 of the first embodiment, the refrigerant heating device 104 of the second embodiment employs the IH heater 12 as a heater for heating the refrigerant, so that the refrigerant is heated quickly. Is possible.

(8) Further, the refrigerant heating device 104 of the second embodiment is installed outside the coil 12a of the first heater 13 and the second temperature sensor 14 as in the refrigerant heater 4 of the first embodiment. Therefore, it is possible to avoid the occurrence of noise in the temperature sensors 13 and 14 and their signal lines due to the influence of electromagnetic waves generated from the coil 12a.

 <Modification of the second embodiment>

 (A)

 In the second embodiment, the force that the temperature sensors 13, 14, and 21 are provided on the surface of the first connection pipe 11 or the second connection pipe 16 The present invention is not limited to this, and the temperature sensors 13, 14, 15 may be provided inside the first connection pipe 11 or the second connection pipe 16. In this case, the temperature of the refrigerant can be accurately detected by the temperature sensor directly contacting the refrigerant.

[Third Embodiment]

 In the first embodiment, temperature sensors 13 and 14 are provided on the upstream side and the downstream side of the IH heater 12, respectively. These two temperature sensors 13 and 14 directly detect the temperature of the refrigerant immediately before or after passing through the IH heater 12 even if the direction of the refrigerant flowing through the first connection pipe 11 is switched between heating and cooling. However, the present invention is not limited to this.

 As yet another embodiment, the refrigerant heating device 204 shown in FIG. 9 further includes a bridge circuit 30 connected to the first connection pipe 11. In addition, the refrigerant heating device 204 includes only one temperature sensor 13 (or 14). The temperature sensor 13 (or 14) is provided on either the upstream side (or the downstream side) of the IH heater 12 in the refrigerant flow direction F1 during heating.

[0083] The bridge circuit 30 has four check valves. The bridge circuit 30 is connected to the straight pipe portion 11a and the loop portion l ib of the first connection pipe 11 as shown in FIG. Even if the direction of the refrigerant flowing through the straight pipe portion 11a of the first connection pipe 11 is switched by the bridge corridor 30, the direction of the refrigerant flowing through the loop portion l ib of the first connection pipe 11 is changed in one direction (FIG. 9). In the direction of arrow F3).

For other configurations, the refrigerant heating device 204 of the third embodiment is the same as that of the first embodiment. Common to refrigerant heating device 4 (except temperature sensor 15 in Fig. 3).

 <Features>

 In the refrigerant heating device 204 of the third embodiment, since the bridge circuit 30 is connected to the first connection pipe 11, even if the direction of the refrigerant flowing through the refrigerant pipe 5 is switched, the bridge circuit 30 causes the first connection pipe to be switched. The direction of the refrigerant flowing through 11 lbs of 1 lb is kept in one direction. Therefore, the temperature of the refrigerant immediately before (or immediately after) passing through the IH heater 12 is directly measured by one temperature sensor 13 (or 14) provided upstream (or downstream) of the IH heater 12. It can be detected.

Industrial applicability

 The present invention can be applied to a refrigerant heating device for heating the refrigerant of an air conditioner.

Claims

The scope of the claims

 [1] At least one connecting pipe (11, 16) connected in the middle of the refrigerant circuit (10) through which the refrigerant circulates;

 A heater (12) for heating the refrigerant flowing in the first connection pipe (11) of the connection pipes (11, 16);

 At least one temperature sensor (13, 14, 15, 21) for detecting the temperature of the refrigerant flowing through the connecting pipe (11, 16);

 With

 Refrigerant heating device (4, 104, 204).

[2] The temperature sensor is

 A first temperature sensor (13) provided upstream of the heater (12) in the direction of refrigerant flow (F1) during heating;

 A second temperature sensor (14) provided downstream of the heater (12) in the direction of refrigerant flow (F1) during heating;

 have,

 The refrigerant heating device (4, 104, 204) according to claim 1.

[3] The temperature sensor further includes a third temperature sensor (15) provided near an intermediate position in the axial direction of the heater (12).

 The refrigerant heating device (4) according to claim 1 or 2.

[4] The second connection pipe (16) of the connection pipes (11, 16) is connected in the middle of the refrigerant circuit (10) at a position different from the first connection pipe (11),

 The refrigerant in the gas state flows through the second connection pipe (16),

 The temperature sensor further includes a fourth temperature sensor (21) provided in the second connection pipe (16).

 The refrigerant heating device (104) according to any one of claims 1 to 3.

[5] It further comprises a bridge circuit (30) connected to the first connection pipe (11) of the connection pipes (11, 16),

The temperature sensors (13, 14) are arranged in the heat flow direction (F1) during heating. (12) provided on either the upstream side or the downstream side,

 The refrigerant heating device (204) according to claim 1.

[6] The temperature sensor (13, 14, 15, 21) is provided on the surface of the connection pipe (11, 16).

 The refrigerant heating device (4, 104, 204) according to any one of claims 1 to 5.

[7] The temperature sensor (13, 14, 15, 21) is provided inside the connection pipe (11, 16).

 The refrigerant heating device (4, 104, 204) according to any one of claims 1 to 5.

[8] The apparatus further includes a control unit (17) that controls the operation of the heater (12) based on the temperature of the refrigerant detected by the one or more temperature sensors (13, 14, 15, 21). The refrigerant heating device (4, 104, 204) according to any one of claims 1 to 5.

[9] The control unit (17) controls the output of the heater (12) based on the temperature of the refrigerant detected by the temperature sensor (13, 14, 15, 21).

 The refrigerant heating device (4, 104, 204) according to claim 8.

[10] The heater (12) is an induction heater.

 The refrigerant heating device (4, 104, 204) according to any one of claims 1 to 9.

[11] The heater (12) has a coil (12a),

 The refrigerant heating device (4, 104, 204) according to claim 10, wherein the temperature sensor (13, 14) is installed outside the coil (12a).

[12] The control unit (17) reduces the output of the heater (12) when at least one of the temperature sensors (13, 14, 15) detects a temperature equal to or higher than a predetermined first temperature. The refrigerant heating device (4) according to claim 8, wherein:

[13] The control unit (17) outputs the output of the heater (12) when any one of the plurality of temperature sensors (13, 14, 15) becomes a predetermined first temperature or higher. The refrigerant heating device (4) according to claim 12, which is reduced.

[14] The first temperature is 80 to 100 ° C.

 The refrigerant heating device (4) according to claim 12, wherein:

[15] The first temperature is obtained by adding 20 to 40 ° C to the temperature of the refrigerant before heating by the heater (12). Temperature

The refrigerant heating device (4) according to claim 12, wherein:

 The first temperature is a temperature obtained by adding 20 to 40 ° C to a change amount of the temperature of the refrigerant every predetermined time.

The refrigerant heating device (4) according to claim 12, wherein:

 The controller (17) stops the heater (12) when at least one of the temperature sensors (13, 14, 15) detects a temperature equal to or higher than a predetermined second temperature.

The refrigerant heating device (4) according to claim 8.

 The control unit (17) stops the heater (12) when any one of the plurality of temperature sensors (13, 14, 15) reaches a predetermined second temperature or higher.

18. The refrigerant heating device (4) according to claim 17.

 The second temperature is 140 to 160 ° C.

18. The refrigerant heating device (4) according to claim 17.

 The controller (17) reduces the output of the heater (12) when a temperature equal to or higher than a predetermined first temperature is detected by at least one of the temperature sensors (13, 14, 15). Control in stages so that the heater (12) is stopped when a temperature of 2 temperatures or more is detected.

The refrigerant heating device (4) according to claim 8.

 The controller (17) stops the heater (12) when at least one of the temperature sensors (13, 14, 15) detects a transient rise of 40-60 ° C.

The refrigerant heating device (4) according to claim 8.

 The control unit (17) is configured to detect the temperature of the refrigerant circuit (10) when at least one of the temperature sensors (13, 14, 15) detects that the refrigerant circuit (10) has risen by 40 to 60 ° C. Stop the heater (12),

The refrigerant heating device (4) according to claim 8.

The controller (17) starts the heater (12) based on the temperature of the refrigerant flowing in the connection pipe (11) detected by one or more temperature sensors (13, 14, 15). Switching between movement and stop, The refrigerant heating device (4) according to claim 8.