WO2010106817A1 - Air conditioning device - Google Patents

Abstract

An air conditioning device which can, even in heating a refrigerant on the suction side of a compression mechanism, perform control which takes into consideration the amount of heat added to the refrigerant, which is sucked into the compression mechanism, in the control of the degree of superheating of the refrigerant. An air conditioning device (1) for performing a refrigeration cycle by including at least a compressor (21), an indoor heat exchanger (41), an indoor fan (42), an outdoor electric expansion valve (24), and an outdoor heat exchanger (23). The air conditioning device (1) is provided with a coil (68), an electromagnetic induction thermister (14), and a control unit (11). The coil (68) generates a magnetic field for heating, by induction, a magnetic material pipe (F2) in order to heat a refrigerant flowing in an accumulator pipe (F). The electromagnetic induction thermister (14) detects the temperature of the magnetic material pipe (F2) which generates heat by induction heating by the coil (68). The control unit (11) performs control for increasing the degree of opening of the electric expansion valve (24) when the rising speed of the temperature detected by the electromagnetic induction thermister (14) is high.

Description

Air conditioner

The present invention relates to an air conditioner.

2. Description of the Related Art Conventionally, an air conditioner that controls a refrigerant circulation amount or the like to control the degree of superheat of refrigerant sucked in a compressor is known.
For example, in the air conditioner described in Patent Document 1 (Japanese Patent Laid-Open No. 7-120083), the amount of refrigerant circulation is controlled by increasing the valve opening degree of the electric expansion valve in accordance with the compressor suction refrigerant temperature. And the degree of superheat of the refrigerant sucked into the compressor can be controlled.

On the suction side of the compressor, the refrigerant refrigerant or the like that is in thermal contact with the refrigerant may be heated by an external heating device to indirectly warm the refrigerant drawn in the compressor.
In the case of using such an external heating device, for example, if an intake refrigerant temperature sensor of the compressor is disposed between a portion to be heated by the external heating device and the suction side of the compressor, the external heating device heats up. The heat applied to the target portion is transferred to the vicinity of the attachment position of the intake refrigerant temperature sensor on the downstream side, making it difficult to accurately detect the intake refrigerant temperature. Then, in the valve opening control of the electric expansion valve based on the detected value of the suction refrigerant temperature sensor of the compressor disposed between the part to be heated by the external heating device and the suction side of the compressor, the valve opening is not performed. The refrigerant circulation amount increases excessively when the temperature is increased too much, and this may not only suppress the excessive increase in the degree of superheat of the refrigerant sucked by the compressor but may cause liquid compression.

In addition, for example, when the part to be heated by the external heating device is provided downstream of the detection position of the suction refrigerant temperature sensor of the compressor and upstream of the suction side of the compressor, The temperature of the suction refrigerant heated by passing through the portion cannot be grasped. Then, in the valve opening degree control of the electric expansion valve based on the detected value of the suction refrigerant temperature sensor arranged upstream of the part to be heated by such an external heating device, the valve opening degree is lowered too much and the refrigerant circulation amount May be excessively decreased, and the degree of superheat of the refrigerant sucked by the compressor may be excessively increased.
The present invention has been made in view of the above-described points, and an object of the present invention is to control the intake refrigerant in the superheat degree control of the intake refrigerant of the compression mechanism, even when the refrigerant on the intake side of the compression mechanism is heated. An object of the present invention is to provide an air conditioner capable of performing control in consideration of the amount of heat applied to the air.

An air conditioner according to a first aspect is an air conditioner including at least a compression mechanism, a refrigerant cooler, an expansion mechanism, and a refrigerant heater, and includes a magnetic field generation unit, a heat generation temperature detection unit, and a control unit. The magnetic field generation unit induction-heats a refrigerant pipe for circulating the refrigerant through the compression mechanism, the refrigerant cooler, the expansion mechanism, and the refrigerant heater and / or a member that makes thermal contact with the refrigerant flowing in the refrigerant pipe. Therefore, a magnetic field is generated. The exothermic temperature detector detects the temperature of the portion that generates heat by induction heating by the magnetic field generator. The control unit detects when the temperature detected by the heat generation temperature detection unit exceeds or exceeds the predetermined heat generation temperature, or when the temperature increase rate detected by the heat generation temperature detection unit exceeds or exceeds the predetermined increase rate. If this happens, overheat protection control is performed to increase the opening of the expansion mechanism.
In this air conditioner, since the heat generation temperature detector is provided, it is possible to grasp the temperature condition of the portion that generates heat by induction heating by the magnetic field generator. Then, when the temperature detected by the heat generation temperature detection unit exceeds or exceeds the predetermined heat generation temperature by the control unit performing overheat protection control, the temperature increase rate detected by the heat generation temperature detection unit is the predetermined increase rate. When the above is reached or exceeded, the opening of the expansion mechanism is increased, and the amount of refrigerant supplied to the suction side of the compression mechanism is increased. For this reason, it can suppress that the superheat degree of the suction | inhalation refrigerant | coolant of a compression mechanism raises abnormally. Thereby, even when the refrigerant on the suction side of the compression mechanism is heated, it is possible to control the superheat degree of the suction refrigerant of the compression mechanism in consideration of the amount of heat applied to the suction refrigerant.

An air conditioner according to a second aspect is the air conditioner according to the first aspect, wherein the magnetic field generator flows in the suction refrigerant pipe and / or the suction refrigerant pipe on the suction side of the compression mechanism among the refrigerant pipes. A magnetic field for inductively heating the member that is in thermal contact with the refrigerant is generated.
In this air conditioner, the refrigerant immediately before being sucked into the compression mechanism is rapidly heated instead of the refrigerant flowing through the refrigerant pipe considerably away from the compression mechanism. The refrigerant flowing on the suction side of the compression mechanism has a high degree of dryness or is in an overheated state, which is obvious when compared with the case where the refrigerant in the gas-liquid two-phase state or the like flowing more upstream changes in latent heat. Temperature is likely to rise because it is easy to change heat.
On the other hand, in this air conditioner, overheating occurs when the temperature detected by the heat generation temperature detection unit becomes equal to or higher than the predetermined heat generation temperature or when the temperature increase rate detected by the heat generation temperature detection unit exceeds the predetermined increase rate. Since protection control is performed, excessive induction heating of the refrigerant passing through the suction side of the compression mechanism can be prevented. Thereby, even if it is a case where the refrigerant | coolant which passes the suction | inhalation side of the compression mechanism which a temperature rise tends to produce is heated, it can suppress that an induction heating part is heated too much.

In the air conditioner according to the third aspect, in the air conditioner according to the first aspect or the second aspect, the control unit performs start-up control and post-startup control. In the start-up control, the magnetic field generating unit is supplied with a magnetic field so that the temperature of the portion that generates heat by induction heating by the magnetic field generating unit reaches a predetermined start-up target temperature while starting the driving of the compression mechanism from a state where the compression mechanism is stopped. Cause it to occur. The post-startup control is performed after the start-up control is finished. When the control unit performs the overheat protection control simultaneously with the control after starting, the expansion mechanism is opened when the temperature detected by the heat generation temperature detecting unit exceeds or exceeds the predetermined heat generation temperature after starting. Raise the degree. The predetermined heat generation temperature after activation is a temperature equal to or higher than the predetermined activation target temperature. The predetermined heat generation temperature after startup may be equal to the predetermined startup target temperature.
In this air conditioner, for post-startup control, when the temperature of the portion that generates heat by induction heating rises above or exceeds a predetermined exothermic temperature after startup, the opening degree of the expansion mechanism is increased, so that induction heating It becomes possible to lower the temperature of the part that generates heat. For this reason, in post-startup control, it is possible to suppress an abnormal temperature rise in a portion that generates heat by induction heating.

In addition, when the predetermined heat generation temperature after the start is not equal to the predetermined target temperature at the start but higher than the predetermined start target temperature, the temperature of the portion that generates heat due to induction heating is excessively increased. Even when processing such as stopping or weakening the supply of the magnetic field from the magnetic field generation unit is performed, the time during which the refrigerant temperature can be maintained at a high temperature by induction heating can be extended.

An air conditioner according to a fourth aspect is the air conditioner according to the third aspect, wherein the control unit reaches a predetermined start-time target temperature when performing the overheat protection control simultaneously with the start-time control. The opening degree of the expansion mechanism is increased when the rate of temperature rise detected by the exothermic temperature detection unit at the time when the temperature rises exceeds or exceeds a predetermined rate of rise.
In this air conditioner, the opening degree of the expansion mechanism is raised when the temperature rise rate rises faster as the temperature rise rate exceeds or exceeds a predetermined rise rate with respect to the detected temperature of the heat generation temperature detector. As for the control after activation, the opening degree of the expansion mechanism is increased when the detected temperature is equal to or higher than a predetermined exothermic temperature with respect to the detected temperature of the exothermic temperature detector. For this reason, in post-startup control, it is determined based on the detected temperature, but in start-up control, it is determined based on the temperature increase rate, so even if it is attempted to cause a rapid temperature increase during startup. Since the opening degree of the expansion mechanism is increased when it exceeds or exceeds the predetermined rising speed, if the predetermined rising speed is exceeded or exceeded before reaching the predetermined heating temperature, the predetermined heating temperature is reached. There is no need to wait for the process of increasing the opening of the expansion mechanism. For this reason, it becomes possible to supply more refrigerant | coolants more reliably with respect to the part which generate | occur | produces heat by induction heating. As a result, it is possible to suppress the extent to which the temperature of the portion that generates heat by induction heating rises vigorously.

In the air conditioner according to the fifth aspect, in the air conditioner according to the fourth aspect, the control unit determines that the rotation speed of the compression mechanism is equal to or greater than the predetermined rotation speed when the control unit determines that the speed has increased or exceeded the predetermined increase speed. The opening degree of the expansion mechanism is increased only when the above is exceeded or exceeded.
In this air conditioner, when the rotation speed of the compression mechanism is equal to or higher than the predetermined rotation speed, the temperature increase rate of the portion that generates heat by induction heating is equal to or higher than the predetermined increase speed. It may or may not exceed. Even in such a case, the refrigerant circulation amount can be increased more reliably by increasing the opening degree of the expansion mechanism in a state where the driving state of the compression mechanism is ensured.

An air conditioner according to a sixth aspect is the air conditioner according to any one of the third to fifth aspects, wherein the air conditioner is configured to grasp a state of the refrigerant passing between the refrigerant cooler and the expansion mechanism. A refrigerant state grasping unit is further provided. When the control unit finishes the startup control, the control unit expands so that the refrigerant subcooling degree grasped using the value grasped by the cooler side refrigerant state grasping part is kept constant at the predetermined target subcooling degree. The supercooling degree constant control for controlling the opening degree of the mechanism is started. Furthermore, the control unit, when performing the overheat protection control at the same time as performing the constant supercooling degree control, when the temperature detected by the exothermic temperature detecting unit becomes equal to or higher than the exothermic temperature during the predetermined supercooling degree constant control or When it exceeds, the opening degree of the expansion mechanism is further increased from the opening degree controlled by the constant supercooling degree control. Here, the heat generation temperature during the predetermined constant degree of subcooling control is a temperature that is equal to or higher than the predetermined start-up target temperature.
In this air conditioner, even when the supercooling degree constant control is performed, it is possible to suppress an abnormal increase in the temperature of the portion that generates heat by induction heating.

In the air conditioner according to the first aspect, even when the refrigerant on the suction side of the compression mechanism is heated, the superheat degree control of the suction refrigerant of the compression mechanism is performed in consideration of the amount of heat applied to the suction refrigerant. It becomes possible to do.
In the air conditioner according to the second aspect, even when the refrigerant that passes through the suction side of the compression mechanism that is likely to increase in temperature is heated, it is possible to suppress excessive heating of the induction heating portion. it can.
In the air conditioner according to the third aspect, the abnormal temperature rise of the portion that generates heat by induction heating can be suppressed in the post-startup control.
In the air conditioner according to the fourth aspect, it is possible to suppress the extent to which the temperature of the portion that generates heat by induction heating rises rapidly.

In the air conditioner according to the fifth aspect, the refrigerant circulation rate can be increased more reliably.
In the air conditioner according to the sixth aspect, even when the supercooling degree constant control is performed, it is possible to suppress an abnormal increase in the temperature of the portion that generates heat by induction heating.

It is a refrigerant circuit figure of the air harmony device concerning one embodiment of the present invention. It is an external appearance perspective view of an electromagnetic induction heating unit. It is an external appearance perspective view which shows the state which removed the shielding cover from the electromagnetic induction heating unit. It is an external appearance perspective view of an electromagnetic induction thermistor. It is an external perspective view of a fuse. It is a schematic sectional drawing which shows the attachment state of an electromagnetic induction thermistor and a fuse. It is a section lineblock diagram of an electromagnetic induction heating unit. It is a figure which shows the mode of magnetic flux. It is a figure which shows the various state transitions in overheat protection control. It is a figure which shows the flowchart of overheating protection control at the time of starting. It is a figure which shows the flowchart of normal time overheat protection control. It is explanatory drawing of the refrigerant | coolant piping of other embodiment (E). It is explanatory drawing of the refrigerant | coolant piping of other embodiment (F). It is a figure which shows the example of arrangement | positioning with the coil and refrigerant | coolant piping of other embodiment (G). It is a figure which shows the example of arrangement | positioning of the bobbin lid of other embodiment (G). It is a figure which shows the example of arrangement | positioning of the ferrite case of other embodiment (G).

Hereinafter, an air conditioner 1 including an electromagnetic induction heating unit 6 according to an embodiment of the present invention will be described as an example with reference to the drawings.
<1-1> Air conditioner 1
FIG. 1 is a refrigerant circuit diagram showing a refrigerant circuit 10 of the air conditioner 1.
The air conditioner 1 is an air conditioner in a space where a use side device is arranged by connecting an outdoor unit 2 as a heat source side device and an indoor unit 4 as a use side device by a refrigerant pipe. , Compressor 21, four-way switching valve 22, outdoor heat exchanger 23, outdoor electric expansion valve 24, accumulator 25, outdoor fan 26, indoor heat exchanger 41, indoor fan 42, hot gas bypass valve 27, capillary tube 28 and An electromagnetic induction heating unit 6 and the like are provided.
The compressor 21, the four-way switching valve 22, the outdoor heat exchanger 23, the outdoor electric expansion valve 24, the accumulator 25, the outdoor fan 26, the hot gas bypass valve 27, the capillary tube 28, and the electromagnetic induction heating unit 6 are included in the outdoor unit 2. Is housed in. The indoor heat exchanger 41 and the indoor fan 42 are accommodated in the indoor unit 4.

The refrigerant circuit 10 includes a discharge pipe A, an indoor gas pipe B, an indoor liquid pipe C, an outdoor liquid pipe D, an outdoor gas pipe E, an accumulator pipe F, a suction pipe G, and a hot gas bypass circuit H. Yes. The indoor side gas pipe B and the outdoor side gas pipe E pass a large amount of refrigerant in the gas state, but the refrigerant passing therethrough is not limited to the gas refrigerant. The indoor side liquid pipe C and the outdoor side liquid pipe D pass a large amount of liquid refrigerant, but the refrigerant passing therethrough is not limited to liquid refrigerant.
The discharge pipe A connects the compressor 21 and the four-way switching valve 22. The discharge pipe A is provided with a discharge temperature sensor 29d for detecting the temperature of the refrigerant passing therethrough. The current supply unit 21e supplies current to the compressor 21. The power supply amount of the current supply unit 21e is detected by the compressor power detection unit 29f. The rotational speed grasping unit 29r detects the rotational speed of the piston of the compressor 21. The indoor side gas pipe B connects the four-way switching valve 22 and the indoor heat exchanger 41. In the middle of the indoor side gas pipe B, a first pressure sensor 29a for detecting the pressure of the refrigerant passing therethrough is provided. The indoor side liquid pipe C connects the indoor heat exchanger 41 and the outdoor electric expansion valve 24. The outdoor liquid pipe D connects the outdoor electric expansion valve 24 and the outdoor heat exchanger 23. The outdoor gas pipe E connects the outdoor heat exchanger 23 and the four-way switching valve 22. In the middle of the outdoor gas pipe E, a second pressure sensor 29g for detecting the pressure of the refrigerant passing therethrough is provided.

The accumulator pipe F connects the four-way switching valve 22 and the accumulator 25 and extends in the vertical direction when the outdoor unit 2 is installed. An electromagnetic induction heating unit 6 is attached to a part of the accumulator tube F. Of the accumulator tube F, at least a heat generating portion whose periphery is covered by a coil 68, which will be described later, is a copper tube F1 in which a coolant is flowing inside, and a magnetic tube F2 provided so as to cover the periphery of the copper tube F1. It is constituted by. The magnetic pipe F2 is configured by SUS (Stainless Used Steel: stainless steel) 430. The SUS430 is a ferromagnetic material, and generates eddy currents when placed in a magnetic field, and generates heat due to Joule heat generated by its own electrical resistance. Portions other than the magnetic pipe F2 among the pipes constituting the refrigerant circuit 10 are made of a copper pipe made of the same material as the copper pipe F1. By performing electromagnetic induction heating in this manner, the accumulator tube F can be heated by electromagnetic induction, and the refrigerant sucked into the compressor 21 via the accumulator 25 can be warmed. Thereby, the heating capability of the air conditioning apparatus 1 can be improved. Further, for example, even when the compressor 21 is not sufficiently warmed at the time of starting the heating operation, the lack of capacity at the time of starting can be compensated for by the rapid heating by the electromagnetic induction heating unit 6. Further, when the four-way switching valve 22 is switched to the cooling operation state and the defrost operation is performed to remove the frost attached to the outdoor heat exchanger 23 or the like, the electromagnetic induction heating unit 6 quickly opens the accumulator tube F. By heating, the compressor 21 can compress the rapidly heated refrigerant as a target. For this reason, the temperature of the hot gas discharged from the compressor 21 can be raised rapidly. Thereby, the time required to thaw frost by defrost operation can be shortened. Thereby, even if it is necessary to perform a defrost operation in a timely manner during the heating operation, the operation can be returned to the heating operation as soon as possible, and the user's comfort can be improved.

The suction pipe G connects the accumulator 25 and the suction side of the compressor 21.
The hot gas bypass circuit H connects a branch point A1 provided in the middle of the discharge pipe A and a branch point D1 provided in the middle of the outdoor liquid pipe D. The hot gas bypass circuit 27 is provided with a hot gas bypass valve 27 that can switch between a state that allows passage of refrigerant and a state that does not allow passage of the refrigerant. In the hot gas bypass circuit H, a capillary tube 28 is provided between the hot gas bypass valve 27 and the branch point D1 to reduce the pressure of refrigerant passing therethrough. Since this capillary tube 28 can be brought close to the pressure after the refrigerant pressure is reduced by the outdoor electric expansion valve 24 during heating operation, the capillary tube 28 is a chamber by supplying hot gas to the outdoor liquid pipe D through the hot gas bypass circuit H. An increase in the refrigerant pressure in the outer liquid pipe D can be suppressed.
The four-way switching valve 22 can switch between a cooling operation cycle and a heating operation cycle. In FIG. 1, the connection state when performing the heating operation is indicated by a solid line, and the connection state when performing the cooling operation is indicated by a dotted line. During the heating operation, the indoor heat exchanger 41 functions as a refrigerant cooler, and the outdoor heat exchanger 23 functions as a refrigerant heater. During the cooling operation, the outdoor heat exchanger 23 functions as a refrigerant cooler, and the indoor heat exchanger 41 functions as a refrigerant heater.

One end of the outdoor heat exchanger 23 is connected to the end of the outdoor heat exchanger 23 on the outdoor gas pipe E side, and the other end is connected to the end of the outdoor heat exchanger 23 on the outdoor liquid pipe D side. Has been. The outdoor heat exchanger 23 is provided with an outdoor heat exchange temperature sensor 29c that detects the temperature of the refrigerant flowing through the air conditioner 1. Furthermore, an outdoor temperature sensor 29b that detects outdoor air temperature is provided upstream of the outdoor heat exchanger 23 in the air flow direction.
In the indoor unit 4, an indoor temperature sensor 43 that detects the indoor temperature is provided. The indoor heat exchanger 41 is provided with an indoor heat exchanger temperature sensor 44 that detects the refrigerant temperature on the indoor liquid pipe C side to which the outdoor electric expansion valve 24 is connected.
The outdoor control unit 12 that controls the devices arranged in the outdoor unit 2 and the indoor control unit 13 that controls the devices arranged in the indoor unit 4 are connected by the communication line 11a, so that the control unit 11 is constituted. The control unit 11 performs various controls for the air conditioner 1.

Further, the outdoor control unit 12 is provided with a timer 95 that counts elapsed time when performing various controls.
Note that a controller 90 that accepts a setting input from the user is connected to the control unit 11.
<1-2> Electromagnetic induction heating unit 6
FIG. 2 shows a schematic perspective view of the electromagnetic induction heating unit 6 attached to the accumulator tube F. FIG. 3 shows an external perspective view of the electromagnetic induction heating unit 6 with the shielding cover 75 removed. FIG. 4 shows a schematic configuration diagram of the electromagnetic induction thermistor 14. FIG. 5 shows a schematic configuration diagram of the fuse 15. FIG. 6 shows a cross-sectional view of the electromagnetic induction thermistor 14 and the fuse 15 attached to the accumulator tube F. FIG. 7 shows a cross-sectional view of the electromagnetic induction heating unit 6 attached to the accumulator tube F. FIG. 8 is an explanatory diagram showing a state in which a magnetic field is generated by the coil 68.

The electromagnetic induction heating unit 6 is disposed so as to cover the magnetic tube F2 that is a heat generating portion of the accumulator tube F from the outside in the radial direction, and causes the magnetic tube F2 to generate heat by electromagnetic induction heating. The heat generating portion of the accumulator tube F has a double tube structure having an inner copper tube F1 and an outer magnetic tube F2.
The electromagnetic induction heating unit 6 includes a first hexagon nut 61, a second hexagon nut 66, a first bobbin lid 63, a second bobbin lid 64, a bobbin body 65, a first ferrite case 71, a second ferrite case 72, and a third ferrite. A case 73, a fourth ferrite case 74, a first ferrite 98, a second ferrite 99, a coil 68, a shielding cover 75, an electromagnetic induction thermistor 14, a fuse 15 and the like are provided.
The first hexagon nut 61 and the second hexagon nut 66 are made of resin, and stabilize the fixed state between the electromagnetic induction heating unit 6 and the accumulator pipe F using a C-shaped ring (not shown). The first bobbin lid 63 and the second bobbin lid 64 are made of resin and cover the accumulator tube F from the radially outer side at the upper end position and the lower end position, respectively. The first bobbin lid 63 and the second bobbin lid 64 have four screw holes for screws 69 for screwing first to fourth ferrite cases 71 to 74, which will be described later, through the screws 69. ing. Furthermore, the second bobbin lid 64 has an electromagnetic induction thermistor insertion opening 64f for inserting the electromagnetic induction thermistor 14 and attaching it to the outer surface of the magnetic tube F2. The second bobbin lid 64 has a fuse insertion opening 64e for inserting the fuse 15 and attaching it to the outer surface of the magnetic tube F2. As shown in FIG. 4, the electromagnetic induction thermistor 14 is an electromagnetic induction thermistor wiring that transmits the detection results of the electromagnetic induction thermistor detector 14a, the outer protrusion 14b, the side protrusion 14c, and the electromagnetic induction thermistor detector 14a as signals to the controller 11. 14d. The electromagnetic induction thermistor detection unit 14a has a shape that follows the curved shape of the outer surface of the accumulator tube F, and has a substantial contact area. As shown in FIG. 5, the fuse 15 includes a fuse detection unit 15a, an asymmetric shape 15b, and a fuse wiring 15d that transmits a detection result of the fuse detection unit 15a to the control unit 11 as a signal. Receiving the notification of temperature detection exceeding the predetermined limit temperature from the fuse 15, the control unit 11 performs control to stop the power supply to the coil 68 to avoid thermal damage of the device. The bobbin main body 65 is made of resin, and the coil 68 is wound around it. The coil 68 is wound spirally around the outside of the bobbin main body 65 with the direction in which the accumulator tube F extends as the axial direction. The coil 68 is connected to a control printed board (not shown) and is supplied with a high-frequency current. The output of the control printed circuit board is controlled by the control unit 11. As shown in FIG. 6, the electromagnetic induction thermistor 14 and the fuse 15 are attached in a state where the bobbin main body 65 and the second bobbin lid 64 are fitted together. Here, in the attached state of the electromagnetic induction thermistor 14, the plate spring 16 is pushed inward in the radial direction of the magnetic body tube F <b> 2, thereby maintaining a good pressure contact state with the outer surface of the magnetic body tube F <b> 2. Similarly, the attachment state of the fuse 15 is also pushed inward in the radial direction of the magnetic tube F2 by the leaf spring 17, so that a good pressure contact state with the outer surface of the magnetic tube F2 is maintained. As described above, since the electromagnetic induction thermistor 14 and the fuse 15 maintain good adhesion to the outer surface of the accumulator tube F, the responsiveness is improved and a rapid temperature change due to electromagnetic induction heating can be detected quickly. I can do it. The first ferrite case 71 has a first bobbin lid 63 and a second bobbin lid 64 sandwiched from the direction in which the accumulator tube F extends, and is screwed and fixed by screws 69. The first ferrite case 71 to the fourth ferrite case 74 contain a first ferrite 98 and a second ferrite 99 made of ferrite, which is a material having a high magnetic permeability. As shown in the sectional view of the accumulator tube F and the electromagnetic induction heating unit 6 in FIG. 7 and the magnetic flux explanatory diagram in FIG. By forming it, the magnetic field is made difficult to leak outside. The shielding cover 75 is disposed on the outermost peripheral portion of the electromagnetic induction heating unit 6 and collects magnetic flux that cannot be drawn by the first ferrite 98 and the second ferrite 99 alone. Almost no leakage magnetic flux is generated outside the shielding cover 75, and the location where the magnetic flux is generated can be determined.
<1-3> Electromagnetic induction heating control The electromagnetic induction heating unit 6 described above is configured so that the accumulator pipe F is activated when starting the heating operation when heating the refrigeration cycle, when assisting the heating capacity, and when performing the defrost operation. Control is performed to generate heat in the magnetic tube F2.

In the following, a description will be given particularly regarding startup. FIG. 9 shows the state transition.
(About initial processing at startup)
The initial process at the time of start-up is a process performed after the heating operation is started until the pressure detected by the first pressure sensor 29a reaches the target high pressure.
When the heating operation instruction is input from the user to the controller 90, the control unit 11 starts the heating operation. When the heating operation is started, the controller 11 waits for the pressure detected by the first pressure sensor 29a to rise to a predetermined target high pressure 39 kg / cm ² after the compressor 21 is started. (Indicated by a point h in FIG. 9), the indoor fan 42 is driven. Thereby, at the stage where the refrigerant passing through the indoor heat exchanger 41 is not warmed, an unpleasant user's discomfort caused by causing an air flow in the unwarmed room is prevented.

Here, in order to shorten the time until the pressure detected by the first pressure sensor 29a rises to 39 kg / cm ² after the compressor 21 is started, the opening degree of the outdoor electric expansion valve 24 is maintained at a fixed opening degree. However, electromagnetic induction heating using the electromagnetic induction heating unit 6 is performed. After confirming that sufficient refrigerant flow in the accumulator tube F is ensured after the compressor 21 is started, the controller 11 starts the rapid pressure increase process. In the rapid pressure-increasing process, the control unit 11 reduces the time required for the detected temperature of the electromagnetic induction thermistor 14 to reach 80 ° C., which is the target accumulator temperature at startup, in order to shorten the coil 68 of the electromagnetic induction heating unit 6. The supply of current to is assumed to be a predetermined maximum supply power (2 kW). The output state at a predetermined maximum supply power by the electromagnetic induction heating unit 6 here is continued until the temperature detected by the electromagnetic induction thermistor 14 reaches 80 ° C., which is the target accumulator temperature at startup.

Thus, in order to shorten the time required to reach the predetermined target high pressure at the time of activation, the opening degree of the outdoor electric expansion valve 24 is maintained at a fixed opening degree, or the detection temperature of the electromagnetic induction thermistor 14 is activated. In order to shorten the time required to reach the desired target accumulator temperature, control is performed to set the output of the electromagnetic induction heating unit 6 to the maximum supply power. However, the induction refrigerant is overheated by this induction heating. The degree may rise abnormally. For this reason, in order to prevent such an abnormal increase in the degree of superheat of the suction refrigerant, the control unit 11 performs overheating protection control (described later) during startup.
(About the processing after the initial stage at startup)
The initial and subsequent processing at the time of startup is processing at the time of startup performed after the pressure detected by the first pressure sensor 29a reaches the target high pressure.

In the processing after the initial stage at the time of starting, after the pressure detected by the first pressure sensor 29a reaches a predetermined target high pressure 39 kg / cm ² , the rotational speed of the compressor 21 is further increased to increase the outdoor electric By increasing the valve opening degree of the expansion valve 24, the amount of refrigerant circulating in the refrigeration cycle is increased, and steady output control is performed to increase the capacity.
After the heating operation is started, the controller 11 once reaches the start target accumulator temperature of 80 ° C. and finishes the initial operation at the start, and then the control unit 11 determines the predetermined maximum supply power ( The detected temperature of the electromagnetic induction thermistor 14 is maintained at around 80 ° C., which is the same target temperature as the startup target accumulator temperature, while the output is suppressed to a steady supply power (1.4 kW) which is an output of 2 kW or less. Next, the output of the electromagnetic induction heating unit 6 is controlled. In the control maintained at around 80 ° C. here, the control unit 11 uses the electromagnetic induction heating unit 6 with the output of the steady supply power (1.4 kW) when the detected temperature of the electromagnetic induction thermistor 14 becomes 60 ° C. or less. Induction heating is started, and when the temperature detected by the electromagnetic induction thermistor 14 reaches 80 ° C., induction heating by the electromagnetic induction heating unit 6 is stopped.

(Regarding normal processing after completion of startup processing)
Steady output control is continued, the rotational speed of the compressor 21 is increased, the opening degree of the outdoor electric expansion valve 24 is increased, and the refrigerant circulation amount of the refrigeration cycle is increased, so that the operation state is reached. When the corresponding circulation amount is reached, the start-up process is terminated, and thereafter normal operation is performed. In this normal operation, the controller 11 opens the opening degree of the outdoor electric expansion valve 24 so that the degree of supercooling of the refrigerant passing through the outlet side of the indoor heat exchanger 41 is kept constant at a predetermined value in the heating operation circuit. The supercooling degree constant control which controls is performed. This degree of supercooling is obtained by the controller 11 calculating the difference between the saturation temperature corresponding to the detected pressure of the second pressure sensor 29g and the temperature detected by the indoor heat exchanger temperature sensor 44.
(Startup overheat protection control)
In the start-up overheat protection control, in order to prevent the degree of superheat of the refrigerant sucked in the compressor 21 from abnormally increasing due to induction heating by the initial maximum supply power (2 kW) at start-up by the electromagnetic induction heating unit 6, In this control, the opening degree of the electric expansion valve 24 is increased.

FIG. 10 shows a flowchart of start-up overheat protection control.
In step S11, if the control part 11 confirms that the detection temperature of the electromagnetic induction thermistor 14 will fall after starting the compressor 21, it will transfer to step S12 (it shows by the point a in FIG. 9).
In step S12, the control unit 11 switches the output of the electromagnetic induction heating unit 6 from the zero state to the maximum supply power (2 kW) (shown as a change from the point b to the point c in FIG. 9), and at the same time, Start counting elapsed time by 95.
In step S13, the control unit 11 determines whether or not the detected temperature of the electromagnetic induction thermistor 14 has reached 80 ° C., which is the target accumulator temperature at startup. When the target accumulator temperature at start-up reaches 80 ° C. (indicated by a point d in FIG. 9), the process proceeds to step S14.

In step S14, the control unit 11 temporarily stops induction heating by the electromagnetic induction heating unit 6 (indicated by a point e in FIG. 9), and ends the count of the timer 95 that has started counting in step S12.
In step S15, the control unit 11 determines whether or not the rotation number detected by the rotation number grasping unit 29r is greater than the overheat suppression estimated rotation number of 82 rps (82 rotations per second). The estimated overheating suppression rotational speed is a rotational speed that is set in advance as the rotational speed at which the degree of superheating of the refrigerant sucked by the compressor 21 hardly increases abnormally based on each design condition of the refrigeration cycle. If the estimated rotational speed of the overheat suppression is less than the suction pressure, the suction pressure is unlikely to be greatly reduced. Therefore, it is estimated that the degree of superheat of the refrigerant sucked in the compressor 21 is not likely to rise abnormally, and the overheating protection control at the start is finished. . When it exceeds the overheat suppression estimated rotational speed, the process proceeds to step S16.

In step S16, the control unit 11 determines whether or not the value of the timer 95 that has finished counting in step S14 is less than 20 seconds, which is the temperature increase rate determination time. This temperature increase rate determination time is a time set in advance as a time corresponding to a temperature increase rate at which the degree of superheat of the refrigerant sucked by the compressor 21 hardly increases abnormally based on each design condition of the refrigeration cycle. . That is, when the time required to reach 80 ° C., which is the target accumulator temperature at start-up, after starting induction heating by the electromagnetic induction heating unit 6 is less than the heating rate determination time (20 seconds), electromagnetic induction Since the rate of temperature increase of the detected temperature of the thermistor 14 is too fast, and the degree of superheat of the refrigerant sucked in the compressor 21 may be abnormally increased, the process proceeds to step S17 and protection is performed. On the other hand, if it takes a time longer than the temperature increase rate determination time, it is estimated that there is no possibility that the superheat degree of the refrigerant sucked in the compressor 21 will rise abnormally, and the startup superheat protection control is terminated.

In step S <b> 17, the control unit 11 increases the opening degree of the outdoor electric expansion valve 24 and performs a valve opening degree increasing process for increasing the flow rate of the refrigerant passing through the accumulator pipe F, whereby the induction performed by the electromagnetic induction heating unit 6. The temperature rise of the accumulator tube F is prevented from becoming too fast due to heating. In the valve opening increase processing here, the opening of the outdoor electric expansion valve 24 is increased by 20 pulses every 20 seconds. This process of increasing by 20 pulses every 20 seconds is repeated until the detected temperature rise rate of the electromagnetic induction thermistor 14 by induction heating becomes a predetermined rate or less. That is, simultaneously with the operation of increasing the opening degree of the outdoor electric expansion valve 24, the process for determining whether or not the speed of temperature rise detected by the electromagnetic induction thermistor 14 does not exceed a predetermined speed is performed at the same time. When the opening degree of the outdoor electric expansion valve 24 is increased, it is determined that there is no possibility that the temperature of the accumulator pipe F will rise too much, and the valve opening degree increasing process is terminated.

This is the end of the overheating protection control at startup.
In addition, after the pressure detected by the first pressure sensor 29a reaches the target high pressure, the steady output control is performed as described above, thereby increasing the frequency of the compressor 21 and the outdoor electric expansion valve 24. The opening degree is further increased, the amount of refrigerant circulating through the refrigeration cycle is further increased, and the capacity of the refrigeration cycle is increased.
(Normal overheat protection control)
The normal overheat protection control detects that the detected temperature of the electromagnetic induction thermistor 14 is temporarily lowered when the degree of opening of the outdoor electric expansion valve 24 is increased while the constant degree of supercooling control is being performed. When induction heating is performed by the electromagnetic induction heating unit 6, this is control for preventing the degree of superheat from rising abnormally due to the induction heating.

FIG. 11 shows a flowchart of normal overheat protection control.
In step S21, when the detected temperature of the electromagnetic induction thermistor 14 becomes 80 ° C. or lower, the control unit 11 outputs the output of the electromagnetic induction heating unit 6 from the zero state by the steady supply power (1.4 kW) (steady level). Raise to.
In step S22, the control unit 11 determines whether or not the detected temperature of the electromagnetic induction thermistor 14 has reached 80 ° C. When the temperature reaches 80 ° C., the process proceeds to step S23.
In step S23, the control unit 11 temporarily stops induction heating by the electromagnetic induction heating unit 6.
In step S24, after stopping induction heating by the electromagnetic induction heating unit 6, the control unit 11 continues to detect how the detection temperature of the electromagnetic induction thermistor 14 rises, exceeding the abnormally elevated temperature of 110 ° C. Determine whether or not. That is, it is determined whether or not there is an overshoot in which the temperature detected by the electromagnetic induction thermistor 14 continues to rise above 80 ° C. despite the induction heating by the electromagnetic induction heating unit 6 being finished. The abnormally elevated temperature of 110 ° C. is a temperature set in advance as a temperature at which an abnormal increase in the degree of superheat of the refrigerant sucked in the compressor 21 occurs when this value is exceeded based on each design condition of the refrigeration cycle. When it is determined that the abnormally rising temperature is exceeded, the process proceeds to step S25. When it is determined that the temperature does not exceed the abnormally rising temperature, it is estimated that there is no possibility that the superheat degree of the refrigerant sucked in the compressor 21 will rise abnormally, and the overheating protection control at the time of start is ended.

In step S25, the controller 11 increases the opening degree by increasing the opening degree of the outdoor electric expansion valve 24 controlled by the constant supercooling degree constant control by an additional 50 pulses (valve opening degree). Adjustment process). Here, the pulse is increased by 50 pulses as a pulse larger than 20 pulses, which is the increment of one opening of the outdoor electric expansion valve 24 in the startup overheat protection control. Thereby, even if an abnormal state is likely to occur in the normal overheat protection control, the abnormal temperature rise of the accumulator tube F can be prevented more quickly.
The normal overheat protection control is thus completed.
Note that, in the normal-time overheat protection control, since the drive rotation speed of the compressor 21 has already exceeded 82 rps, the determination in the start-up overheat protection control is unnecessary.

<Characteristics of the air conditioner 1 of the present embodiment>
(1)
In the induction heating by the electromagnetic induction heating unit 6, the temperature of the refrigerant flowing through the accumulator pipe F immediately before being sucked into the compressor 21 is rapidly increased instead of the refrigerant flowing through a portion far from the compressor 21 in the refrigeration cycle. I am letting. The refrigerant flowing on the suction side of the compressor 21 has a high degree of dryness or is in an overheated state, compared with a case where the refrigerant in a gas-liquid two-phase state or the like flowing more upstream changes the latent heat. Sensible heat changes easily and temperature rises. In addition, since the refrigerant sucked in the compressor 21 is heated, the heat generated in the magnetic pipe F2 is affected by heat conduction, etc., so it is not possible to grasp the temperature of the refrigerant actually sucked into the compressor 21. difficult.

In such a situation, in the control performed by the air conditioner 1 of the present embodiment, not the temperature of the refrigerant actually sucked into the compressor 21, but the temperature state of the magnetic body tube F2 of the accumulator tube F that generates heat by induction heating. Is grasped by the electromagnetic induction thermistor 14. Then, based on the temperature detected by the electromagnetic induction thermistor 14, the opening degree of the outdoor electric expansion valve 24 is increased and supplied to the suction side of the compressor 21 so that the degree of superheat of the suction refrigerant of the compressor 21 does not rise abnormally. The amount of refrigerant to be increased can be increased. As a result, when the refrigerant on the suction side of the compressor 21 is heated, even if it is difficult to determine the actual temperature of the suction refrigerant, the amount of heat applied to the suction refrigerant is determined by the electromagnetic induction thermistor 14. Thus, an abnormal increase in the degree of superheat of the refrigerant sucked in the compressor 21 can be suppressed.
(2)
Further, in the overheat protection control at the start of the present embodiment, the opening degree of the outdoor electric expansion valve 24 is increased in a situation where the temperature of the magnetic pipe F2 of the accumulator pipe F suddenly rises due to induction heating at the start. By supplying this refrigerant, it is possible to suppress an abnormal increase in the degree of superheat of the refrigerant sucked in the compressor 21. And this overheating protection control at the time of startup considers the drive rotation speed of the compressor 21, and normally selects an overheat suppression estimated rotation speed that is predetermined as a rotation speed at which no abnormal temperature rise occurs. Even in a situation where the driving state of the compressor 21 is ensured, the opening degree of the outdoor electric expansion valve 24 is increased only when the temperature of the magnetic pipe F2 rapidly increases. For this reason, at the time of start-up, it is possible to avoid the opening degree of the outdoor electric expansion valve 24 from being increased at a stage where the drive rotational speed of the compressor 21 has not increased so much. As a result, the opening degree of the outdoor electric expansion valve 24 is increased more than necessary, thereby making it difficult for the high-low pressure difference to occur, and until the detected pressure of the first pressure sensor 29a reaches a predetermined target high-pressure pressure of 39 kg / cm ^2. It is possible to prevent the time required for the operation from being prolonged and the high-temperature refrigerant from being unable to be supplied to the indoor heat exchanger 41.

Further, the timing for increasing the opening degree of the outdoor electric expansion valve 24 in the start-up overheat protection control is not based on whether or not the temperature detected by the electromagnetic induction thermistor 14 exceeds a certain temperature, but the temperature increase rate is determined. The standard. For this reason, it is not necessary to make a determination as to whether or not this determination temperature has been exceeded while newly providing another determination temperature or the like that is higher than the startup target accumulator temperature. In addition, the temperature of the accumulator tube F after that time is more likely to rise more quickly when it is understood that the temperature has exceeded a certain rate of temperature rise than when it is determined that the determination temperature has been exceeded. Since this is a situation, in the above-described embodiment in which it is possible to grasp the case where such an abnormal temperature rise is likely to occur, the reliability of the apparatus can be improved.
For example, in the control to increase the opening degree of the outdoor electric expansion valve 24 when the determination temperature is exceeded, considering the case where 90 ° C. is set as the temperature higher than the target accumulator temperature at startup, the detection of the electromagnetic induction thermistor 14 Even if it takes a few minutes for the temperature to exceed 90 ° C. from 89 ° C., and even if a certain amount of time passes after that, even if it is predicted that the temperature will increase only by a few degrees C., the degree of opening of the outdoor electric expansion valve 24 is It will be raised. On the other hand, in the overheat protection control at the time of start-up in the above embodiment, the opening degree of the outdoor electric expansion valve 24 is increased only when a temperature increase rate that exceeds 80 ° C. in 20 seconds is detected. It is possible to prevent the discharge refrigerant temperature from being lowered due to unnecessarily increasing the opening degree of the outdoor electric expansion valve 24.
(3)
Further, in the normal overheat protection control, when the detection temperature of the electromagnetic induction thermistor 14 exceeds the abnormally elevated temperature 110 ° C. by performing induction heating when the supercooling degree constant control is performed, the degree of supercooling is increased. The opening degree is further increased from the opening degree of the outdoor electric expansion valve 24 controlled by the constant control. For this reason, the amount of refrigerant passing through the accumulator tube F can be more reliably compared to control in which the opening degree of the outdoor electric expansion valve 24 is merely adjusted to a certain degree of opening when the abnormally rising temperature exceeds 110 ° C. Since it can be increased, an abnormal increase in the degree of superheat of the refrigerant sucked by the compressor 21 can be more reliably suppressed.

The normal overheat protection control is performed in a state in which the refrigerant circulation amount of the refrigeration cycle is more stable than that at the time of startup, and a rapid increase in the temperature of the accumulator tube F is unlikely to occur. It is not necessary to make a determination based on the rising speed, and the reliability can be sufficiently ensured by a simple determination method of determining whether or not the abnormally rising temperature exceeds 110 ° C.
This also increases the amount of refrigerant sucked in the compressor 21, so that the heat input time to the magnetic pipe F <b> 2 by induction heating of the electromagnetic induction heating unit 6 can be extended.
Further, until the electromagnetic induction thermistor 14 detects an abnormally elevated temperature of 110 ° C., which is higher than 80 ° C. at which the induction heating by the electromagnetic induction heating unit 6 is stopped, the degree of opening of the outdoor electric expansion valve 24 is controlled at a constant degree of supercooling. Since the opening degree of the outdoor electric expansion valve 24 is not increased, the time during which the refrigerant temperature can be maintained at a high temperature by induction heating can be extended.

<Other embodiments>
As mentioned above, although embodiment of this invention was described based on drawing, a specific structure is not restricted to these embodiment, It can change in the range which does not deviate from the summary of invention.
(A)
In the above embodiment, the case where SUS430 is used as the material of the magnetic tube F2 has been described as an example.
However, the present invention is not limited to this. For example, a conductor such as iron, copper, aluminum, chromium, nickel, and an alloy containing at least two kinds of metals selected from these groups can be used.
Examples of magnetic materials include ferrites, martensites, and those containing a combination of these two, but they are ferromagnetic and have a relatively high electrical resistance. A material having a Curie temperature higher than the temperature range is preferred.

The accumulator tube F here requires more electric power, but does not have to include a magnetic body and a material containing the magnetic body, and contains a material to be subjected to induction heating. It may be a thing.
For example, the magnetic material may constitute all of the accumulator pipe F, or may be formed only on the inner surface of the accumulator pipe F, and is contained in the material constituting the accumulator pipe F pipe. May exist.
(B)
In the above embodiment, the case where the conditions for increasing the opening degree of the outdoor electric expansion valve 24 are different between the startup overheat protection control and the normal overheat protection control has been described as an example.
However, the present invention is not limited to this. For example, the conditions for increasing the opening degree of the outdoor electric expansion valve 24 may be the same in the startup overheat protection control and the normal overheat protection control.

(C)
In the above embodiment, the case where the control for keeping the degree of supercooling constant after the start-up control is finished has been described as an example.
However, the present invention is not limited to this. For example, the degree of change in the refrigerant distribution state in the refrigeration cycle may be controlled to be maintained for a predetermined time in a predetermined distribution state or within a predetermined distribution range. As the detection of the refrigerant distribution state, for example, the refrigerant distribution state is grasped by grasping the liquid level of the refrigerant by, for example, providing a sight glass in the condenser of the refrigeration cycle, and this distribution state is a predetermined distribution state or Stabilization control may be performed so as to be within a predetermined distribution range.
(D)
In the above embodiment, the case where the electromagnetic induction heating unit 6 is attached to the accumulator tube F in the refrigerant circuit 10 has been described.

However, the present invention is not limited to this.
For example, other refrigerant pipes other than the accumulator pipe F may be provided. In this case, a magnetic material such as the magnetic material tube F2 is provided in the refrigerant piping portion where the electromagnetic induction heating unit 6 is provided.
(E)
In the said embodiment, the case where the accumulation pipe F was comprised as a double pipe | tube of the copper pipe F1 and the magnetic body pipe | tube F2 was mentioned and demonstrated.
However, the present invention is not limited to this.
As shown in FIG. 12, for example, the magnetic member F2a and the two stoppers F1a and F1b may be arranged inside the accumulator pipe F or the refrigerant pipe to be heated. Here, the magnetic member F2a contains a magnetic material, and is a member that generates heat by electromagnetic induction heating in the above embodiment. The stoppers F1a and F1b always allow the refrigerant to pass through at two locations inside the copper tube F1, but do not allow the magnetic member F2a to pass through. Thereby, the magnetic member F2a does not move even when the refrigerant flows. For this reason, the target heating position of the accumulator tube F or the like can be heated. Furthermore, since the magnetic member F2a that generates heat and the refrigerant are in direct contact, the heat transfer efficiency can be improved.

(F)
The magnetic member F2a described in the other embodiment (L) may be positioned with respect to the pipe without using the stoppers F1a and F1b.
As illustrated in FIG. 13, for example, the copper pipe F1 may be provided with two bent portions FW, and the magnetic member F2a may be disposed inside the copper pipe F1 between the two bent portions FW. Even in this case, the movement of the magnetic member F2a can be suppressed while allowing the refrigerant to pass therethrough.
(G)
In the above embodiment, the case where the coil 68 is spirally wound around the accumulator tube F has been described.
However, the present invention is not limited to this.

For example, as shown in FIG. 14, the coil 168 wound around the bobbin main body 165 may be arranged around the accumulator tube F without being wound around the accumulator tube F. Here, the bobbin main body 165 is disposed so that the axial direction is substantially perpendicular to the axial direction of the accumulator tube F. Further, the bobbin main body 165 and the coil 168 are arranged separately in two so as to sandwich the accumulator tube F.
In this case, for example, as shown in FIG. 15, the first bobbin lid 163 and the second bobbin lid 164 penetrating the accumulator tube F may be arranged in a state of being fitted to the bobbin main body 165. Good.
Further, as shown in FIG. 16, the first bobbin lid 163 and the second bobbin lid 164 may be sandwiched and fixed by the first ferrite case 171 and the second ferrite case 172. In FIG. 16, the case where the two ferrite cases are arranged so as to sandwich the accumulator tube F is taken as an example, but may be arranged in four directions as in the above embodiment. Moreover, you may accommodate the ferrite similarly to the said embodiment.

(H)
In the above-described embodiment, whether the temperature increase rate is fast or not is determined by the time required from the start of induction heating by the electromagnetic induction heating unit 6 until the start-up target accumulator tube temperature reaches 80 ° C. The case where the determination is made based on whether the time is less than (20 seconds) has been described as an example.
However, the method for grasping the temperature rise rate is not limited to such a grasping method.
For example, instead of actually grasping the temperature rise rate, the controller 90 holds an information table in advance, and the control unit 11 refers to this information table so that the temperature rise rate is predicted and the outdoor expansion valve 24 is used. Control such as increasing the valve opening degree may be performed.
As such an information table, for example, the current detection temperature of the electromagnetic induction thermistor 14, the amount of heating of the accumulator tube F by the electromagnetic induction heating unit 6, the amount of refrigerant circulating through the accumulator tube F, the refrigerant passing through the accumulator tube F The data etc. which matched each condition, such as the density of this, and external temperature, and the value calculated beforehand as a temperature rise rate corresponding to the condition are mentioned. In this way, when the temperature increase rate is calculated in advance, the thermal conductivity of the magnetic tube F2 and the copper tube F1, the heat transfer coefficient between the magnetic tube F2 and the copper tube F1, the copper tube F1 and the refrigerant. It is desirable to calculate based on the heat transfer coefficient between

Here, the amount of heating of the accumulator tube F by the electromagnetic induction heating unit 6 can be converted from the amount of power supplied from the current supply unit 21e detected by the compressor power detection unit 29f. The refrigerant circulation amount passing through the accumulator pipe F and the density of the refrigerant passing through the accumulator pipe F are obtained by the driving speed of the piston of the compressor 21 known by the revolution speed grasping part 29r and the first pressure sensor 29a. It can be converted from the high pressure that is being measured, the low pressure that is being grasped by the second pressure sensor, and the like. The outside air temperature can be grasped as the temperature detected by the outdoor temperature sensor 29b. In this way, when the information table is held in the controller 90 in advance, the processing load on the control unit 11 can be reduced.
Note that the controller 90 holds a predetermined relational expression without causing the controller 90 to hold such an information table, and based on the values obtained from each sensor described above, the predicted temperature increase rate is The control unit 11 may calculate.

In addition, the amount of power supplied to the electromagnetic induction heating unit 6 by the current supply unit 21e is based on, for example, a predetermined output (for example, 2 kW) and another predetermined output (for example, 1.4 kW) based on the outside air temperature. ), The information table and the calculation can be simplified.
As described above, when the control unit 11 does not actually grasp the temperature rise rate but calculates it from an information table or a predetermined relational expression, the time for actually measuring the temperature rise rate is obtained. Since it becomes unnecessary, it becomes possible to perform more rapid processing.
(I)
In the above-described embodiment, the detected temperature of the electromagnetic induction thermistor 14 is maintained at around 80 ° C., which is the target accumulator temperature at startup, in the steady output control after the initial stage of startup. When the temperature is 60 ° C. or less, induction heating by the electromagnetic induction heating unit 6 is started with the output of the above-described steady supply power (1.4 kW), and when the detected temperature of the electromagnetic induction thermistor 14 reaches 80 ° C., the electromagnetic induction heating unit 6 The case where the process of stopping the induction heating by the above is described as an example.

However, the control for maintaining the detected temperature of the electromagnetic induction thermistor 14 at around 80 ° C. in the steady output control is not limited to such control.
For example, the control unit 11 performs PI control on the current supply frequency of the electromagnetic induction heating unit 6 based on the detected temperature of the electromagnetic induction thermistor 14 so as to maintain the detected temperature of the electromagnetic induction thermistor 14 at around 80 ° C. May be. In this PI control, the control unit 11 repeats this set with one set of supplying current to the electromagnetic induction heating unit 6 while maintaining a constant constant power supply (1.4 kW) for 30 seconds continuously. Alternatively, the frequency may be adjusted based on the elapsed time from when the current supply to the latest electromagnetic induction heating unit 6 is completed until the temperature detected by the electromagnetic induction thermistor 14 falls to 80 ° C. again. That is, the longer the elapsed time, the higher the frequency of repeating the set may be controlled.
<Others>
The embodiments of the present invention have been described above with some examples, but the present invention is not limited to these. For example, combined embodiments obtained by appropriately combining different portions of the above-described embodiments within the scope that can be implemented by those skilled in the art from the above description are also included in the present invention.

By utilizing the present invention, even when the refrigerant on the suction side of the compression mechanism is heated, control is performed in consideration of the amount of heat applied to the suction refrigerant in the superheat degree control of the suction refrigerant of the compression mechanism. Therefore, it is particularly useful in an air conditioner that heats a refrigerant by induction heating.

1 Air Conditioner 11 Control Unit (Cooler-side Refrigerant State Grasping Unit)
14 Electromagnetic induction thermistor (heating temperature detection)
21 Compressor (compression mechanism)
23 Outdoor heat exchanger (refrigerant heater)
24 Outdoor electric expansion valve (expansion mechanism)
29a 1st pressure sensor (cooler side refrigerant | coolant state grasping | ascertainment part)
29g Second pressure sensor 41 Indoor heat exchanger (refrigerant cooler)
44 Indoor heat exchange temperature sensor (cooler side refrigerant state grasping part)
68 Coil (Magnetic field generator)
F Accumulation pipe (refrigerant piping, suction refrigerant piping)

Japanese Patent Laid-Open No. 7-120083

Claims (6)

1. An air conditioner (1) including at least a compression mechanism (21), a refrigerant cooler (41), an expansion mechanism (24), and a refrigerant heater (23),
   Refrigerant piping (F) for circulating the refrigerant through the compression mechanism (21), the refrigerant cooler (41), the expansion mechanism (24), and the refrigerant heater (23), and / or the refrigerant piping ( F) a magnetic field generator (68) for generating a magnetic field for inductively heating a member that is in thermal contact with the refrigerant flowing through the medium;
   An exothermic temperature detector (14) for detecting the temperature of the portion that generates heat by induction heating by the magnetic field generator (68);
   When the temperature detected by the exothermic temperature detector (14) exceeds or exceeds a predetermined exothermic temperature, or when the temperature detected by the exothermic temperature detector (14) rises above a predetermined rate. A controller (11) that performs overheat protection control to increase the opening of the expansion mechanism (24) when
   An air conditioner (1) comprising:
2. The magnetic field generator (68) is in thermal contact with the refrigerant flowing through the suction refrigerant pipe (F) and / or the suction refrigerant pipe (F) on the suction side of the compression mechanism (21) in the refrigerant pipe. Generating a magnetic field for inductively heating the member
   The air conditioner (1) according to claim 1.
3. The controller (11) is configured to control a temperature of a portion that generates heat by induction heating by the magnetic field generator (68) while starting the driving of the compression mechanism (21) from a state where the compression mechanism (21) is stopped. Performing start-up control for generating a magnetic field in the magnetic field generator (68) so as to reach a predetermined start-up target temperature, and post-startup control performed after the start-up control is finished,
   When the control unit (11) performs the overheat protection control simultaneously with the post-startup control, the temperature detected by the heat generation temperature detection unit (14) is equal to or higher than the predetermined start-up target temperature. The opening of the expansion mechanism (24) is increased when the temperature exceeds or exceeds a predetermined exothermic temperature after startup,
   The air conditioner (1) according to claim 1 or 2.
4. When the overheat protection control is performed simultaneously with the start-up control, the control unit (11) detects the exothermic temperature detection unit (14) when reaching the predetermined start-up target temperature. Increasing the opening of the expansion mechanism (24) when the temperature increase rate exceeds or exceeds the predetermined increase rate;
   The air conditioner (1) according to claim 3.
5. When the control unit (11) determines that the speed has increased or exceeded the predetermined ascending speed, the rotation speed of the compression mechanism (21) is equal to or higher than the predetermined speed. Only, increase the opening of the expansion mechanism (24),
   The air conditioner (1) according to claim 4.
6. A cooler side refrigerant state grasping part (44, 29a, 11) for grasping the state of the refrigerant passing between the refrigerant cooler (41) and the expansion mechanism (24);
   The control unit (11) has a predetermined degree of refrigerant supercooling that is obtained by using values obtained by the cooler side refrigerant state grasping unit (44, 29a, 11) when the start-up control is completed. Starting a supercooling degree constant control for controlling the opening degree of the expansion mechanism (24) so as to be kept constant at the target supercooling degree;
   When the control unit (11) performs the overheat protection control at the same time when the supercooling degree constant control is being performed, the temperature detected by the heat generation temperature detection unit (14) is equal to or higher than the predetermined start-up target temperature. The temperature of the expansion mechanism (24) is further increased above the degree of opening controlled by the degree of supercooling degree control when the heat generation temperature exceeds or exceeds the temperature of the predetermined degree of degree of supercooling degree constant control. ,
   The air conditioner (1) according to any one of claims 3 to 5.

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