JP2011002190A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heating efficiency of a refrigerant in a refrigerating device having electromagnetic induction heating units.SOLUTION: An air conditioning device 1 has a refrigerant pipe constituting a refrigerant circuit 10. The electromagnetic induction heating units 6A1, 6A2 are mounted on a return pipe 3F of the refrigerant pipe. The return pipe 3F has a straight pipe part 3F1 provided with the electromagnetic induction heating unit 6A1 and a straight pipe part 3F3 provided with the electromagnetic induction heating unit 6A2. Further, the return pipe 3F has a curved pipe part 3F2 between the two straight pipe parts 3F1, 3F3. In the straight pipe parts 3F1, 3F3, the refrigerant is heated by the electromagnetic induction heating units 6A1, 6A2.

Description

  The present invention relates to a refrigeration apparatus that circulates refrigerant, and more particularly, to a refrigeration apparatus that heats a circulating refrigerant by electromagnetic induction heating.

  The refrigeration apparatus includes a radiator that releases heat of the refrigerant in the refrigeration cycle, a heater that gives heat to the refrigerant, and the like. In a general vapor compression refrigeration cycle, for example, in a heater provided outdoors for heating, the refrigerant obtains heat by exchanging heat with outdoor air, and indoors for cooling. Heat is obtained by exchanging heat with room air in the provided heater.

  By the way, in Patent Document 1 (Japanese Patent Application Laid-Open No. 11-2111195), the refrigerant obtains heat by a petroleum refrigerant heater provided separately from a heater of a vapor compression refrigeration cycle that obtains heat from indoor or outdoor air. A system has been proposed. In this petroleum refrigerant heater, oil is burned and the refrigerant flowing in the petroleum refrigerant heater is heated. When heating units such as petroleum refrigerant heaters and gas burners that receive energy supply other than the thermal energy of air in the atmosphere are used, restrictions such as indoor and outdoor temperatures are required when the refrigerant requires heat. The refrigerant can be heated without receiving it. Further, as the heating unit, an electromagnetic induction heating system that receives supply of electrical energy can be adopted for heating the refrigerant. Thus, in a heating unit that receives an energy supply other than the thermal energy of the atmosphere, rapid heating is facilitated by increasing the amount of energy input.

  If a heating unit that heats by the electromagnetic induction heating method as described above is employed in a refrigeration apparatus, the refrigerant flowing in the pipe must be heated, which is described, for example, in Patent Document 2 (Japanese Patent Laid-Open No. 8-326997). As described above, the member heated by electromagnetic induction heating must be brought into thermal contact with the refrigerant to be heated and heated.

  However, in the case of a refrigeration apparatus, unlike the case where an electromagnetic induction heating method is applied to a chemical plant or the like described in Patent Document 2, there is a limitation in pressure loss in the refrigeration circuit, so that it is described in Patent Document 2. It is difficult to heat the refrigerant in thermal contact with the member while stirring the complicated member.

  In the case of a refrigerant used in a refrigeration system, the refrigerant often changes from a liquid refrigerant to a gas refrigerant when heated. However, since the thermal conductivity of the gas refrigerant is generally lower than that of the liquid refrigerant, Heating efficiency tends to decrease as the proportion of refrigerant increases.

  The subject of this invention is improving the heating efficiency of a refrigerant | coolant in a freezing apparatus provided with an electromagnetic induction heating unit.

  The refrigeration apparatus according to the first invention includes a refrigerant pipe and an electromagnetic induction heating unit. The refrigerant pipe has an inlet and an outlet for the refrigerant, and a curved pipe part that is curved between the inlet and the outlet, a first extension part that extends from the inlet of the curved pipe part, and a second extension that extends from the outlet of the curved pipe part Has a part. The electromagnetic induction heating unit heats a member that makes thermal contact with the refrigerant passing through at least the first extending portion and the second extending portion directly or indirectly by electromagnetic induction.

  According to the present invention, a gas refrigerant and a liquid refrigerant having a high gas refrigerant content at the interface with a member that is heated at the first extending portion of the refrigerant pipe and becomes a gas refrigerant and makes thermal contact with the refrigerant. The refrigerant is efficiently heated in the second extending portion by stirring the bent tube portion using the density difference and heating again with a member in thermal contact with the refrigerant in the second extending portion of the refrigerant pipe. can do.

  The refrigerating apparatus according to the second invention is the refrigerating apparatus according to the first invention, wherein the member that makes thermal contact is a refrigerant pipe.

  According to the present invention, when the refrigerant is gasified by receiving heat from the refrigerant pipe, the ratio of the gas refrigerant existing in the space around the inner surface of the first extending portion of the refrigerant pipe is increased, and the ratio of the liquid refrigerant is increased. Decrease. By stirring the refrigerant in the curved pipe part, the ratio of the gas refrigerant in the space around the inner surface of the pipe of the second extending part and the ratio of the liquid refrigerant are improved in the direction of increasing the ratio of the liquid refrigerant. The efficiency of heat transfer is improved. In this case, since there is no member that causes a pressure loss that inhibits the flow of the refrigerant in the first extending portion and the second extending portion, it is possible to prevent the performance of the refrigeration circuit from being deteriorated.

  A refrigeration apparatus according to a third aspect of the present invention is the refrigeration apparatus of the first or second aspect of the present invention, wherein the refrigerant pipe has a first extending portion including a first straight pipe portion, and a second extending portion is a second straight pipe portion. And the curved tube portion includes at least one U-shaped portion.

  According to the present invention, the refrigerant speed is rapidly increased by guiding the refrigerant from the straight first straight pipe portion and the second straight pipe portion where the flow rate of the refrigerant does not slow down to the U-shaped portion of the curved pipe portion therebetween. As the traveling direction is changed, it can be efficiently stirred.

  A refrigeration apparatus according to a fourth aspect of the present invention is the refrigeration apparatus according to any one of the first to third aspects of the present invention, wherein the bending tube portion has an agitating member for agitating the refrigerant in an internally curved portion.

  According to the present invention, in addition to the stirring effect using the difference in density between the gas refrigerant and the liquid refrigerant in the curved pipe portion, the extraordinary stirring effect called the stirring effect by the stirring member is combined, so that a higher stirring effect can be obtained.

  A refrigeration apparatus according to a fifth aspect of the present invention is the refrigeration apparatus according to any one of the first to fourth aspects, wherein the first extending portion and the second extending portion extend in parallel. Moreover, the electromagnetic induction coil which the electromagnetic induction heating unit has is attached so that it can be separated from the refrigerant pipe by being pulled out along the direction in which the first extending portion and the second extending portion extend.

  According to the present invention, the number of coils can be reduced by heating the first extending portion and the second extending portion with one coil. In addition, maintenance can be performed with the electromagnetic induction heating unit pulled out and separated from the refrigerant pipe.

  A refrigeration apparatus according to a sixth aspect is the refrigeration apparatus according to any one of the first to fourth aspects, wherein the electromagnetic induction heating unit has at least two electromagnetic induction coils. The at least two electromagnetic induction coils are arranged to face each other across the first extending portion and the second extending portion in a direction penetrating the surface including the first extending portion and the second extending portion.

  According to the present invention, since the first extending portion and the second extending portion can be heated by a set of coils, an electromagnetic induction heating unit can be configured by a set of coils that can be easily removed while suppressing an increase in cost. it can.

  A refrigeration apparatus according to a seventh aspect of the present invention is the refrigeration apparatus according to any one of the first to sixth aspects of the invention, wherein the refrigerant pipe has a curved pipe part disposed below the second extending part.

  According to the present invention, the density of the liquid layer of the refrigerant is higher than that of the gas layer, and since the refrigerant flows upward from the first extending portion through the curved tube portion to the second extending portion, the liquid layer is accumulated below. It is easy and since the thermal conductivity of the liquid layer accumulated underneath is high, the liquid layer is heated in the first extending portion, and the heating efficiency is improved. Similarly, when the refrigerant flows upward from the second extending portion, the heating efficiency is also improved in the second extending portion.

  In the refrigeration apparatus according to the first aspect of the invention, electromagnetic induction heating can be stably and accurately controlled by improving the difference between the heating efficiency of the second extending portion and the heating efficiency of the first extending portion.

  In the refrigeration apparatus according to the second aspect of the invention, the heating efficiency of the second extending portion can be improved without degrading the performance of the refrigerant circuit.

  In the refrigeration apparatus according to the third aspect of the invention, it is possible to improve the stirring function in the bending tube portion and improve the heating efficiency improvement effect of the second stretching portion.

  In the refrigeration apparatus according to the fourth aspect of the present invention, the stirring function can be improved by the synergistic effect of stirring by the curved tube portion and the stirring member, and the improvement effect of the heating efficiency of the second extending portion can be improved.

  In the refrigeration apparatus according to the fifth aspect of the invention, there is an effect of reducing the cost by simplifying the structure of the electromagnetic induction heating unit and improving the maintainability.

  In the refrigeration apparatus according to the sixth aspect of the invention, the maintainability of the electromagnetic induction heating unit can be improved.

  In the refrigeration apparatus according to the seventh aspect of the invention, the heating efficiency is improved at least in the first stretching section, and leakage of energy consumption required for heating can be suppressed.

Schematic which shows the refrigerant circuit which comprises the freezing apparatus of 1st Embodiment. The perspective view which shows the external appearance of an example of an electromagnetic induction heating unit. Sectional drawing of the electromagnetic induction heating unit of FIG. The conceptual diagram for demonstrating the electric power supply to an electromagnetic induction heating unit. The block diagram which shows the structure of the control part of a refrigerant circuit. The conceptual diagram which shows the electromagnetic induction heating unit periphery of the freezing apparatus of 2nd Embodiment. The conceptual diagram which shows the electromagnetic induction heating unit periphery of the freezing apparatus of 3rd Embodiment. The conceptual diagram which shows the electromagnetic induction heating unit periphery of the freezing apparatus of 4th Embodiment. Sectional drawing which shows the electromagnetic induction heating unit periphery of the freezing apparatus of 4th Embodiment. The conceptual diagram which shows the electromagnetic induction heating unit periphery of the freezing apparatus of 5th Embodiment. (A) Side surface sectional drawing of the bending tube part of 6th Embodiment. (B) XX sectional drawing of Fig.11 (a). (C) Sectional drawing which shows the other example of a bending pipe part.

[First Embodiment]
[Outline of air conditioner]
The outline of the configuration of the air-conditioning apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a refrigerant circuit diagram showing a refrigerant circuit 10 of the air conditioner 1. The air conditioner 1 includes a refrigerant circuit 10 in which an outdoor unit 2 and an indoor unit 4 are connected by a refrigerant pipe, and the heat energy supplied from the outdoor unit 2 of the heat source side device is used for the utilization side device. Air conditioning of the space where the indoor unit 4 is arranged is performed.

  The air conditioner 1 includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, an outdoor electric expansion valve 24, an accumulator 25, an outdoor fan 26, a hot gas bypass valve 27, which are accommodated in the outdoor unit 2. Various devices such as the capillary tube 28 and the electromagnetic induction heating units 6A1 and 6A2 and the indoor heat exchanger 41 and the indoor fan 42 housed in the indoor unit 4 are provided.

  The compressor 21 is rotationally driven by a compressor motor (not shown). Electric power is supplied to the compressor motor from a commercial power supply via an inverter. In that case, it converts into alternating current of a desired frequency from a commercial power source with an inverter. The compressor 21 is configured such that the rotational speed of the compressor motor is changed by changing the frequency of the alternating current to be supplied, whereby the discharge amount of the compressor 21 is changed.

  In the air conditioner 1 of FIG. 1, in order to connect the various devices described above, the discharge pipe 3A, the indoor side gas pipe 3B, the indoor side liquid pipe 3C, the outdoor side liquid pipe 3D, the outdoor side gas pipe 3E, and the return pipe The refrigerant circuit 10 includes 3F, a suction pipe 3G, and a hot gas bypass circuit 3H. Among these pipes through which the refrigerant passes, the indoor side gas pipe 3B and the outdoor side gas pipe 3E pass a large amount of gas refrigerant in the gas state, but the refrigerant passing therethrough is not limited to the gas refrigerant. Further, the indoor liquid pipe 3C and the outdoor liquid pipe 3D pass a lot of liquid refrigerant in the liquid state, but the refrigerant passing therethrough is not limited to the liquid refrigerant.

  Connection of each device of the refrigerant circuit 10 using the above-described piping will be described. The discharge pipe 3 </ b> A connects the discharge port of the compressor 21 and the first port of the four-way switching valve 22. The indoor side gas pipe 3 </ b> B connects the second port of the four-way switching valve 22 and one end of the indoor heat exchanger 41. The indoor side liquid pipe 3 </ b> C connects the other end of the indoor heat exchanger 41 and one end of the outdoor electric expansion valve 24. The outdoor liquid pipe 3D connects the other end of the outdoor electric expansion valve 24 and one end of the outdoor heat exchanger 23. The outdoor gas pipe 3E connects the other end of the outdoor heat exchanger 23 and the third port of the four-way switching valve 22. The return pipe 3F connects the fourth port of the four-way switching valve 22 and the inlet of the accumulator 25. The suction pipe 3G connects the outlet of the accumulator 25 and the suction port of the compressor 21. The hot gas bypass circuit 3H connects a branch point A1 provided in the middle of the discharge pipe 3A and a branch point D1 provided in the middle of the outdoor liquid pipe 3D. In the hot gas bypass circuit 3H, a hot gas bypass valve 27 for switching between a state where the refrigerant is allowed to pass and a state where the refrigerant is not allowed is disposed in the middle of the hot gas bypass circuit 3H.

  The return pipe 3F includes a straight pipe part 3F1, a U-shaped curved pipe part 3F2 following the straight pipe part 3F1, and a straight pipe part 3F3 following the curved pipe part 3F2. A first electromagnetic induction heating unit 6A1 is attached to the straight pipe portion 3F1, and a second electromagnetic induction heating unit 6A2 is attached to the straight pipe portion 3F3. Further, a return pipe temperature sensor 39 is attached to the straight pipe portion 3F3 on the downstream side of the electromagnetic induction heating unit 6A2.

  The air conditioner 1 can switch between a cooling operation cycle and a heating operation cycle by the four-way switching valve 22. 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. That is, during the heating operation, the refrigerant passes between the second port and the second port of the four-way switching valve 22 and between the third port and the fourth port, and the indoor heat exchanger 41 serves as a refrigerant cooler (condenser). The outdoor heat exchanger 23 functions as a refrigerant heater (evaporator). On the other hand, during the cooling operation, the refrigerant passes between the first port and the third port of the four-way switching valve 22 and between the second port and the fourth port, and the outdoor heat exchanger 23 is a refrigerant cooler (condenser). The indoor heat exchanger 41 functions as a refrigerant heater (evaporator).

  The air conditioner 1 includes a control unit 11 for performing the control. The control unit 11 includes an outdoor control unit 12 and an indoor control unit 13 connected by a communication line 11a. The outdoor control unit 12 controls devices disposed in the outdoor unit 2, and the indoor control unit 13 Controls the equipment arranged in the machine 4. A control system including the control unit 11 will be described later.

[Configuration of electromagnetic induction heating unit]
FIG. 2 is a perspective view showing the appearance of the electromagnetic induction heating unit, and FIG. 3 is a cross-sectional view showing the configuration of the electromagnetic induction heating unit. Since the electromagnetic induction heating unit 6A1 and the electromagnetic induction heating unit 6A2 have the same configuration, the following description will be given for the electromagnetic induction heating unit 6A1. The straight pipe portion 3F1 of the return pipe 3F to which the electromagnetic induction heating unit 6A1 is attached has a double pipe structure having an inner copper pipe 3Fa and an SUS (Stainless Used Steel) pipe Co made of an outer magnetic body. It has become. The electromagnetic induction coil 68 of the electromagnetic induction heating unit 6A1 is wound around the straight pipe portion 3F1 and disposed so as to cover the SUS pipe Co from the outside in the radial direction. The SUS tube Co is a magnetic material, and magnetic flux concentrates in the interior during electromagnetic induction heating. Therefore, an eddy current is generated so as to wrap the magnetic flux passing through the SUS tube Co, and the SUS tube Co generates heat. Since there is no member through which current flows outside the SUS tube Co, the SUS tube Co becomes a member to be heated. Here, the member to be heated refers to a member that is directly heated by a current flowing by electromagnetic induction. At this time, the heating amount P (W) is given by P = RI ² by the eddy current I (A) and the resistance value R (Ω) of the SUS tube Co itself. The magnetic SUS tube Co is made of, for example, ferritic stainless steel or martensitic stainless steel.

  The electromagnetic induction heating unit 6A1 includes a first hexagon nut 61, a second hexagon nut 66, a first bobbin lid 63, a second bobbin lid 64, a bobbin main 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, an electromagnetic induction coil 68, a shielding cover 75, a thermistor (not shown) and a fuse (not shown) are provided. The first hexagon nut 61 is made of resin, and fixes the electromagnetic induction heating unit 6A1 to the straight pipe portion 3F1 in the vicinity of the upper end of the electromagnetic induction heating unit 6A1. The second hexagon nut 66 is made of resin, and fixes the electromagnetic induction heating unit 6A1 to the straight pipe portion 3F1 in the vicinity of the lower end of the electromagnetic induction heating unit 6A1.

 The first bobbin lid 63 is made of resin and is one of the members that determine the relative position between the straight pipe portion 3F1 and the electromagnetic induction coil 68 in the electromagnetic induction heating unit 6, and SUS above the electromagnetic induction heating unit 6A1. The tube Co is covered from the surroundings. The second bobbin lid 64 is made of resin, has the same shape as the first bobbin lid 63, and covers the SUS tube Co from the periphery below the electromagnetic induction heating unit 6A1.

  The first bobbin lid 63 has a tubular portion 63c for piping for fixing the straight pipe portion 3F1 and the electromagnetic induction heating unit 6A1 in cooperation with the first hexagon nut 61 while penetrating the straight pipe portion 3F1. ing. The first bobbin lid 63 has a substantially T-shaped hook-shaped portion 63a formed inwardly from the outer peripheral portion in order to hold the coil first portion 68b and the coil second portion 68c while passing therethrough. Yes. The first bobbin lid 63 has a plurality of heat radiation openings 63b penetrating in the vertical direction in order to release heat staying between the bobbin main body 65 and the SUS tube Co to the outside.

  First to fourth ferrite cases 71 to 74 are screwed to the first bobbin lid 63 with screws 69. A thermistor and a fuse can be inserted from the first bobbin lid 63. The thermistor is attached so as to be in direct contact with the outer surface of the SUS tube Co, and exhibits a resistance value corresponding to the temperature of the outer surface of the SUS tube Co. The fuse is attached so as to be in direct contact with the outer surface of the SUS tube Co. When the surface temperature of the SUS tube Co exceeds a predetermined value, the conduction is interrupted to stop electromagnetic induction heating.

  On the lower surface side of the first bobbin lid 63, a bobbin cylinder upper portion 63g that fits the bobbin main body 65 by being located inside the upper end cylindrical portion of the bobbin main body 65 extends downward. The bobbin cylinder upper portion 63g is formed to extend in a penetrating direction from a portion along the outer edge of each opening so as not to close a penetrating state of a necessary opening such as the heat radiation opening 63b described above.

  Note that the opening and shape of the first bobbin lid 63 are the same for the second bobbin lid 64, and each member number of the 63rd series in the first bobbin lid 63 is the same as that of the 64th series in the second bobbin lid 64. It shows corresponding to each member number, and the description is omitted.

  As shown in FIG. 3, the bobbin main body 65 has a cylindrical portion 65 a around which the electromagnetic induction coil 68 is wound. The bobbin main body 65 has a first winding stop 65s formed to protrude in the radial direction at a portion slightly lowered from the upper end, and a second winding formed to protrude in the radial direction at a portion slightly raised from the lower end. And a stop portion 65t. The first winding stop 65s has a coil holding groove (not shown) formed inward in the radial direction so as to sandwich the first coil portion 68b, and a recess in the radial direction in order to sandwich the second coil portion 68c. It has a formed coil holding groove (not shown). A space is formed between the bobbin body 65 and the SUS pipe Co.

  A coil winding portion 68a (see FIG. 4) of the electromagnetic induction coil 68 is spirally wound on the outside of the bobbin main body 65 with the straight tube portion 3F1 extending in the axial direction. The coil first portion 68b extends to one end side of the electromagnetic induction coil 68 with respect to the coil winding portion 68a, and the coil second portion 68c extends to the other end side opposite to the one end side of the electromagnetic induction coil 68. .

  The coil first portion 68b and the coil second portion 68c are connected to the control printed board 18 as shown in FIG. The control printed circuit board 18 is supplied from a high frequency power source having a frequency of about several tens of kHz and an output of about several kW, for example. The electromagnetic induction coil 68 is supplied with a high-frequency current from the control printed circuit board 18. The control printed circuit board 18 is controlled by the control unit 11.

 The first ferrite case 71, the second ferrite case 72, the third ferrite case 73, and the fourth ferrite case 74 are arranged at positions that cover the four outer directions in plan view and extend along the direction in which the SUS tube Co extends. The first bobbin lid 63 and the second bobbin lid 64 are sandwiched in the extending direction of the SUS pipe Co. The first ferrite case 71 has a portion for accommodating the first ferrite 98 and the second ferrite 99. The second ferrite case 72, the third ferrite case 73, and the fourth ferrite case 74 are the same as the first ferrite case 71.

  The electromagnetic induction coil 68 is located inside the first to fourth ferrite cases 71 to 74. The first ferrite 98 of the first to fourth ferrite cases 71 to 74 forms a path of magnetic flux by ferrite, which is a material having high permeability, and when a current is passed through the electromagnetic induction coil 68, the SUS tube Co and magnetic flux passing outside the electromagnetic induction coil 68 are concentrated. In particular, the first ferrite 98 is accommodated in the accommodating portions of the first to fourth ferrite cases 71 to 74 near the upper end and the lower end of the electromagnetic induction heating unit 6. The second ferrite 99 is also the same as the first ferrite 98 except for the arrangement position and shape, and is arranged at a position near the outside of the bobbin main body 65 in the accommodating portion of the first to fourth ferrite cases 71 to 74. . In the electromagnetic induction heating unit 6A1, since the first ferrite 98 and the second ferrite 99 are provided outside the electromagnetic induction coil 68, most of the magnetic flux that flows around the outside of the electromagnetic induction coil 68 flows, thereby reducing leakage magnetic flux. Has been able to.

  When the electromagnetic induction coil 68 is supplied with a high-frequency current from the control printed circuit board 18, a magnetic flux is generated at the coil winding portion 68a. Specifically, most of the magnetic flux passes through the SUS tube Co which is a ferromagnetic material inside the coil winding portion 68a, and most of the magnetic flux passes through the first ferrite 98 outside the coil winding portion 68a. , Through the second ferrite 99 and the shielding cover 75. The magnetic flux that exits the SUS tube Co, passes through the first ferrite 98, the second ferrite 99, and the shielding cover 75 and returns to the SUS tube Co again is the air in which the SUS tube Co, the first ferrite 98, and the shielding cover 75 are in close proximity. Pass through. For example, when viewed in a cross section including the first ferrite case 71 and the third ferrite case 73 as shown in FIG. 3, the magnetic flux that has spread out from the SUS tube Co to the left and right first crosses the air and first the first bobbin lid 63. Enters the first ferrite 98 on the side, passes from the first ferrite 98 through the second ferrite 99, and exits into the air from the first ferrite 98 on the second bobbin lid 64 side. Most of the magnetic flux generated in the air from the first ferrite 98 on the second bobbin lid 64 side passes again through the SUS tube Co toward the first bobbin lid 63. The magnetic flux closed so that it may become substantially elliptical shape in the plane of FIG. 3 arises. Due to the magnetic flux generated in this way, a current (eddy current) due to electromagnetic induction is generated in the SUS tube Co, a large amount of heat is generated near the surface of the SUS tube Co, and the SUS tube Co and the copper tube 3Fb1 having high thermal conductivity. Heat is transferred to the refrigerant flowing inside.

  The shielding cover 75 is disposed on the outermost peripheral portion of the electromagnetic induction heating unit 6A1 and collects magnetic flux that cannot be drawn only by the first ferrite 98 and the second ferrite 99. As shown in FIG. 2, the shielding cover 75 is fixed by being screwed to the first ferrite case 71 via screws 70a, 70b, 70c, and 70d. Thereby, in the electromagnetic induction heating unit 6A1, almost no leakage magnetic flux is generated outside the shielding cover 75, and the influence of magnetism on the surroundings can be prevented.

[Control system]
FIG. 5 is a block diagram showing an outline of the configuration of the control system. The outdoor control unit 12 and the indoor control unit 13 of the control unit 11 are connected by a communication line 11a (see FIG. 1) and transmit / receive data to / from each other. The outdoor control unit 12 and the indoor control unit 13 receive the detection results of various sensors, and the devices that configure the outdoor unit 2 and the indoor unit 4 according to the state of the air conditioner 1 and the surrounding conditions and setting conditions. In order to output various commands, a microcomputer (not shown) and a memory (not shown) are incorporated.

  The outdoor control unit 12 of the control unit 11 includes a suction side pressure sensor 31, a discharge side pressure sensor 32, a suction side temperature sensor 33, a discharge side temperature sensor 34, a heat exchange temperature sensor 35, a liquid side temperature sensor 36, and an outdoor temperature sensor. Various sensors such as 37 and the return pipe temperature sensor 39 are connected, and the detection result of each sensor is input.

  The suction side pressure sensor 31 detects the pressure of the refrigerant on the suction side of the compressor 21. The discharge side pressure sensor 32 detects the pressure of the refrigerant on the discharge side of the compressor 21. The suction side temperature sensor 33 detects the temperature of the refrigerant on the suction side of the compressor 21. The discharge side temperature sensor 34 detects the temperature of the refrigerant on the discharge side of the compressor 21. The heat exchanger temperature sensor 35 detects the temperature of the refrigerant flowing in the outdoor heat exchanger 23. The liquid side temperature sensor 36 is located between the outdoor heat exchanger 23 and the outdoor electric expansion valve 24 and detects the temperature of the refrigerant on the liquid side of the outdoor heat exchanger 23. The outdoor temperature sensor 37 is provided on the inlet side of the unit of the outdoor unit 2 and detects the temperature of the outside air that has flowed into the unit. The return pipe temperature sensor 39 is provided on the downstream side of the electromagnetic induction heating unit 6A2 in the straight pipe portion 3F3, and detects the temperature of the refrigerant in the straight pipe portion 3F3.

  The outdoor control unit 12 is connected to two control printed circuit boards 18, a compressor 21, a four-way switching valve 22, an outdoor electric expansion valve 24, an outdoor fan 26, and other devices or control terminals for the devices. Two kinds of devices operate under the control of the outdoor control unit 12.

  A signal instructing the output of the electromagnetic induction heating units 6A1 and 6A2 is given from the outdoor control unit 12 to the control printed circuit board 18, and the control printed circuit board 18 sends an electromagnetic induction coil 68 to the electromagnetic induction coil 68 in accordance with an instruction from the outdoor control unit 12. The supplied high frequency current increases or decreases. As a result, the eddy current generated in the SUS pipe Co increases or decreases, and the heating amount of the refrigerant flowing through the straight pipe portions 3F1 and 3F3 is controlled. At this time, it is not necessary to make the heating amounts of the two electromagnetic induction heating units 6A1 and 6A2 the same. For example, since the refrigerant passing through the upstream straight pipe portion 3F1 is more likely to be heated because the proportion of the liquid refrigerant is larger, the heating amount of the electromagnetic induction heating unit 6A1 can be increased. Moreover, it is not necessary to make the section length heated by electromagnetic induction heating unit 6A1, 6A2 in the straight pipe parts 3F1, 3F3 the same. For example, since the refrigerant passing through the downstream straight pipe portion 3F1 is less likely to be heated because the ratio of the gas refrigerant is increased, the heating section of the electromagnetic induction heating unit 6A2 can be set longer. Moreover, since the stirring effect in the curved tube portion 3F2 varies depending on the flow rate of the refrigerant, for example, the ratio of the heating amount of the electromagnetic induction heating units 6A1 and 6A2 can be changed according to the refrigerant circulation amount. The setting in the control unit 11 can be performed by acquiring data in an actual machine while changing the heating amount in advance and obtaining an optimum setting.

  The outdoor control unit 12 is provided with an inverter circuit (not shown), and the rotational speeds of the compressor 21 and the outdoor fan 26 are controlled by the output frequency of the inverter circuit. The four-way switching valve 22 has a drive unit, and the outdoor control unit 12 is connected to the drive unit of the four-way switching valve 22 when switching the connection of the four-way switching valve 22 in switching between heating operation and cooling operation. To output a switching command. Further, the outdoor control unit 12 outputs a control signal instructing the opening degree in order to adjust the opening degree of the outdoor electric expansion valve 24.

  A liquid side temperature sensor 43, a gas side temperature sensor 44, and a room temperature sensor 45 are connected to the indoor control unit 13, and the detection results of each sensor are input. The liquid side temperature sensor 43 is provided on the other end side of the indoor heat exchanger 41 and detects the temperature of the refrigerant on the liquid side of the indoor heat exchanger 41. The gas side temperature sensor 44 is provided on one end side of the indoor heat exchanger 41 and detects the temperature of the refrigerant on the gas side of the indoor heat exchanger 41. The indoor temperature sensor 45 is provided on the inlet side of the unit of the indoor unit 4 and detects the temperature of the indoor air flowing into the unit.

  The indoor control unit 13 is connected with an indoor fan 42, a wind direction adjusting mechanism 46, a display unit 47, and the like, and various devices of the indoor unit 4 operate under the control of the indoor control unit 13. The indoor control unit 13 is provided with an inverter circuit (not shown), and the rotation speed of the indoor fan 42 is controlled by the frequency of the output of the inverter circuit. Since the air direction adjusting mechanism 46 adjusts the direction of the wind blown into the room by changing the angle of a louver (not shown) provided in the indoor unit 4, the indoor control unit 13 controls the angle and operation of the louver. Output a signal. The indoor control unit 13 outputs a signal instructing display to the display unit 47 to perform various displays. For example, the state of the electromagnetic induction heating units 6A1 and 6A2 can be displayed on the display unit 47.

[Overview of refrigerant circuit operation]
(Heating operation)
During the heating operation, the four-way switching valve 22 is in the state indicated by the solid line in FIG. That is, the refrigerant discharged from the discharge side of the compressor 21 sequentially passes through the four-way switching valve 22, the indoor heat exchanger 41, the outdoor electric expansion valve 24, the outdoor heat exchanger 23, the four-way switching valve 22, and the accumulator 25. Around, it is sucked from the suction side of the compressor 21. At this time, the refrigerant passing through the return pipe 3F is heated by the electromagnetic induction heating units 6A1 and 6A2 in the straight pipe portions 3F1 and 3F3. The refrigerant circulating through the refrigerant circuit 10 is, for example, carbon dioxide, HFC, HCFC, or the like.

  First, the high-temperature and high-pressure gas refrigerant compressed by the compressor 21 is sent to the indoor heat exchanger 41 via the four-way switching valve 22. At this time, the pressure of the refrigerant sucked by the suction side pressure sensor 31 is detected on the suction side of the compressor 21, and the pressure of the refrigerant discharged by the discharge side pressure sensor 32 is detected on the discharge side. At the same time, the temperature of the refrigerant sucked by the suction side temperature sensor 33 is detected on the suction side of the compressor 21, and the temperature of the refrigerant discharged by the discharge side temperature sensor 34 is detected on the discharge side.

  In order to perform efficient heating, the rotation speed of the compressor 21 is obtained, for example, by calculating the difference between the set temperature by the remote controller and the room temperature as a heating load, or the temperature of the refrigerant discharged from the compressor 21 and the room heat exchange. The heating load is obtained by using the temperature of the refrigerant in the vessel 41 and the like, and is controlled according to the heating load. In order to prevent failure of the air conditioner 1 and the like, based on the detection results of the suction side pressure sensor 31 and the discharge side pressure sensor 32, the pressure of the refrigerant sucked into the compressor 21 is higher than a predetermined low pressure, and the compressor The pressure of the refrigerant discharged from 21 is controlled to fall within a range lower than a predetermined high pressure. When the pressure exceeds the predetermined high pressure, the rotation speed of the compressor 21 is decreased and the discharge pressure of the compressor 21 is decreased. For the same reason, the temperature of the refrigerant discharged from the compressor 21 is monitored by the discharge side temperature sensor 34 so as not to be higher than a predetermined high temperature. Since the temperature and pressure must be sufficiently managed as described above, the above-described pressure and temperature can be easily controlled by heating accurately and stably by the electromagnetic induction heating units 6A1 and 6A2. It has a positive effect on the good heating and the prevention of failure of the air conditioner 1. In particular, since the temperature rise due to the heating amount of the electromagnetic induction heating units 6A1 and 6A2 becomes dominant at the start of operation, the electromagnetic induction heating unit 6A1 is fast in response speed, stable, and capable of controlling the heating amount with high accuracy. , 6A2 is advantageous.

  Before entering the indoor heat exchanger 41, the gas side temperature sensor 44 detects the inlet temperature of the high-temperature and high-pressure gas refrigerant discharged from the compressor 21. And the heat exchange between a refrigerant | coolant and room air is performed in the indoor heat exchanger 41, and a refrigerant | coolant is cooled. For example, when the refrigerant is HFC or the like, the state changes from a gas refrigerant to a gas-liquid two-phase state or a liquid refrigerant. At this time, the indoor heat exchanger 41 functions as a condenser, and the state of heat exchange of the refrigerant in the indoor heat exchanger 41 is changed by controlling the rotation speed of the indoor fan 42. The temperature of the refrigerant leaving the indoor heat exchanger 41 is detected by the liquid side temperature sensor 43.

  The refrigerant leaving the indoor heat exchanger 41 is decompressed by the outdoor electric expansion valve 24. The opening degree of the outdoor electric expansion valve 24 is adjusted according to the heating load, and the opening degree of the outdoor electric expansion valve 24 is adjusted so that the decompressed refrigerant has a predetermined degree of superheat. The degree of superheat of the refrigerant is, for example, a difference between the temperature of the refrigerant in the outdoor heat exchanger 23 detected by the heat exchange temperature sensor 35 and the temperature of the refrigerant sucked into the compressor 21 detected by the suction side temperature sensor 33. Based on.

  The refrigerant that has been decompressed by the outdoor electric expansion valve 24 and is in a gas-liquid two-phase state is sent to the outdoor heat exchanger 23. In the outdoor heat exchanger 23, the refrigerant is heated by heat exchange with the outdoor air to become a gas refrigerant. At this time, the outdoor heat exchanger 23 functions as an evaporator, and an outdoor air flow is generated by the outdoor fan 26 to promote heat exchange between the outdoor air and the refrigerant. Are controlled so that heat exchange can be performed so that the COP becomes high.

  In the outdoor heat exchanger 23, frost formation may occur when the evaporation temperature of the refrigerant becomes 0 ° C. or less. Therefore, the inflow refrigerant temperature of the outdoor heat exchanger 23 detected by the liquid side temperature sensor 36 and the outdoor temperature sensor 37 The presence or absence of frost formation is determined based on the outside temperature. If there is frost, the efficiency of heat exchange is reduced, leading to an increase in power consumption and a decrease in comfort. Therefore, when there is frost, a defrosting operation is performed.

  The gas refrigerant evaporated in the outdoor heat exchanger 23 is sent to the accumulator 25 via the four-way switching valve 22. In the return pipe 3F before the accumulator 25 enters, the refrigerant sequentially passes through the straight pipe part 3F1, the curved pipe part 3F2, and the straight pipe part 3F3. The refrigerant heated by the electromagnetic induction heating unit 6A1 of the straight pipe portion 3F1 is stirred by the curved pipe portion 3F2 because the density of the gas refrigerant is small and the density of the liquid refrigerant is high, and further, the electromagnetic induction heating unit 6A2 of the straight pipe portion 3F3. Heated. Therefore, it is possible to avoid the concentration of the gas refrigerant in the portion of the straight pipe portion 3F3 that receives heat transfer from the inner surface of the pipe, and it is possible to prevent the heating efficiency from being significantly reduced as compared with the straight pipe portion 3F1. The temperature of the refrigerant after being heated by the electromagnetic induction heating unit 6A2 is detected by a return pipe temperature sensor 39. The control of the heating amount in the electromagnetic induction heating units 6A1 and 6A2 is feedback controlled by the outputs of the electromagnetic induction heating units 6A1 and 6A2 so that the temperature detected by the return pipe temperature sensor 39 becomes the target temperature. For example, the controller 11 stores in advance the optimal combination of heating amounts of the electromagnetic induction heating units 6A1 and 6A2 for the refrigerant circulation amount, the detection temperature of the return pipe temperature sensor 39, and the target temperature, thereby suppressing energy consumption. Efficient heating.

  The refrigerant flowing through the return pipe 3F and flowing into the accumulator 25 is gas-liquid separated in the accumulator 25, so that the liquid refrigerant does not return to the compressor 21. Thereby, liquid compression occurs in the compressor 21 and the compressor 21 is prevented from malfunctioning.

(Cooling operation)
During the cooling operation, the four-way switching valve 22 is in the state indicated by the dotted line in FIG. That is, the refrigerant discharged from the discharge side of the compressor 1 sequentially passes through the four-way switching valve 22, the outdoor heat exchanger 23, the outdoor electric expansion valve 24, the indoor heat exchanger 41, the four-way switching valve 22, and the accumulator 25. Around, it is sucked from the suction side of the compressor 1.

  In the case of cooling operation, the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchanger 41 functions as an evaporator. As described above, in the cooling operation, the functions of the outdoor heat exchanger 23 and the indoor heat exchanger 41 are switched with respect to the heating operation.

  First, the high-temperature and high-pressure gas refrigerant compressed by the compressor 21 is sent to the outdoor heat exchanger 23 via the four-way switching valve 22. At this time, the pressure of the refrigerant sucked by the suction side pressure sensor 31 is detected on the suction side of the compressor 21, and the pressure of the refrigerant discharged by the discharge side pressure sensor 32 is detected on the discharge side. At the same time, the temperature of the refrigerant sucked by the suction side temperature sensor 33 is detected on the suction side of the compressor 21, and the temperature of the refrigerant discharged by the discharge side temperature sensor 34 is detected on the discharge side.

  For example, the difference between the set temperature by the remote controller or the like and the room temperature is obtained as the cooling load, or the cooling load is obtained by using the temperature of the refrigerant discharged from the compressor 21 and the temperature of the refrigerant in the outdoor heat exchanger 23. The rotational speed of the compressor 21 is controlled according to the cooling load. Moreover, in order to prevent the failure of the air conditioner 1, the pressure and temperature of the refrigerant discharged from the compressor 21 are limited as in the heating operation.

  In the outdoor heat exchanger 23, heat exchange between the refrigerant and the outdoor air is performed to cool the refrigerant. For example, when the refrigerant is HFC, the state changes from a gas refrigerant to a gas-liquid two-phase state or a liquid refrigerant. At this time, the temperature of the refrigerant flowing inside the outdoor heat exchanger 23 is detected by the heat exchange temperature sensor 35. Further, by controlling the rotation speed of the outdoor fan 26, the state of heat exchange of the refrigerant in the outdoor heat exchanger 23 changes. Then, the temperature of the refrigerant sent from the outdoor heat exchanger 23 to the outdoor electric expansion valve 24 is detected by the liquid side temperature sensor 36.

  The refrigerant sent from the outdoor heat exchanger 23 is decompressed by the outdoor electric expansion valve 24. At this time, the opening degree of the outdoor electric expansion valve 24 is adjusted according to the cooling load, and the opening degree of the outdoor electric expansion valve 24 is adjusted so that the decompressed refrigerant has a predetermined degree of superheat. The degree of superheat of the refrigerant is, for example, a difference between the temperature of the refrigerant in the outdoor heat exchanger 23 detected by the heat exchange temperature sensor 35 and the temperature of the refrigerant sucked into the compressor 21 detected by the suction side temperature sensor 33. Based on.

  The refrigerant that has been decompressed by the outdoor electric expansion valve 24 and is in a gas-liquid two-phase state is sent to the indoor heat exchanger 41. In the indoor heat exchanger 41, the refrigerant is heated by heat exchange with room air to become a gas refrigerant. Indoor air flow is generated by the indoor fan 42 to promote heat exchange between the indoor air and the refrigerant.

  The gas refrigerant evaporated in the indoor heat exchanger 41 is sent to the accumulator 25 via the four-way switching valve 22. In the return pipe 3F before the accumulator 25 enters, the electromagnetic induction heating units 6A1 and 6A2 are heated in the same manner as in the heating operation. The refrigerant flowing through the return pipe 3F and flowing into the accumulator 25 is gas-liquid separated in the accumulator 25, so that the liquid refrigerant does not return to the compressor 21. Thereby, liquid compression occurs in the compressor 21 and the compressor 21 is prevented from malfunctioning.

  In cooling, since an operation for releasing heat to the outside is performed, it is not necessary to supply heat for air conditioning from the electromagnetic induction heating units 6A1 and 6A2. However, there is a scene where accurate and stable heating is required in order to prevent liquid back and ensure the amount of refrigerant circulation for the purpose of preventing failure of the air conditioner 1.

(Defrosting operation)
During the heating operation, when the outside air temperature decreases, the outdoor heat exchanger 23 may be frosted. When the outdoor heat exchanger 23 is frosted, the efficiency of heat exchange in the outdoor heat exchanger 23 is reduced, so that a defrosting operation is necessary. Therefore, during the heating operation, for example, when the temperature of the outdoor heat exchanger 23 is detected by the heat exchange temperature sensor 35 and it is determined that the detected temperature is equal to or lower than the predetermined temperature and frost formation occurs, Switch from heating operation to defrosting operation.

  In a refrigeration apparatus that does not have a heating unit, for example, the outdoor heat exchanger 23 functions as a condenser, and high-temperature and high-pressure gas refrigerant is supplied from the compressor 21 to the outdoor heat exchanger 23 to heat the outdoor heat exchanger 23. To defrost. Similarly, when the heating unit is provided, the four-way switching valve 22 is switched so that the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchanger 41 is supplementarily used by the electromagnetic induction heating units 6A1 and 6A2. The outdoor heat exchanger 23, which is a condenser, can be heated while suppressing the heat exchange capability between the indoor air and the refrigerant.

  When defrosting is performed using the electromagnetic induction heating units 6A1 and 6A2 as an auxiliary, the refrigerant is supplied through the dotted line connection of the four-way switching valve 22 as in the cooling operation. The high-temperature and high-pressure gas refrigerant discharged from the compressor 21 enters the outdoor heat exchanger 23 and is cooled by exchanging heat with frost attached to the outdoor heat exchanger 23. The refrigerant depressurized by the outdoor electric expansion valve 24 enters the indoor heat exchanger 41. However, in the defrosting operation performed during the heating operation, it is preferable not to cool the room, so the amount of heat exchange in the indoor heat exchanger 41 is small. Thus, the opening degree of the outdoor electric expansion valve 24 and the rotational speed of the compressor 21 are adjusted, and the rotational speed of the indoor fan 42 is also lowered. The amount of heating in the electromagnetic induction heating units 6A1 and 6A2 is increased by an amount corresponding to a decrease in the amount of heat exchange in the indoor heat exchanger 41 as compared with the cooling operation so as to have a predetermined degree of superheat on the suction side of the compressor 21. At this time, since the electromagnetic induction heating units 6A1 and 6A2 heat the refrigerant divided into the return pipe 3F, the controllability and responsiveness of the heating amount are high and the outdoor heat exchanger 23 functions as a condenser during heating operation. It can fully cope with the defrosting operation.

  Further, when the heating capacity of the electromagnetic induction heating units 6A1 and 6A2 is sufficiently large, the outdoor heat exchanger 23 can be defrosted while performing the heating operation. In the case of the defrosting operation while heating, the four-way switching valve 22 is switched to the solid line. Also, the hot gas bypass valve 27 is opened to open the hot gas bypass circuit 3H, and the outdoor electric expansion valve 24 is throttled so that the refrigerant returned from the indoor heat exchanger 41 and the high-temperature and high-pressure discharged from the compressor 21 A mixed refrigerant with a gas refrigerant is supplied to the outdoor heat exchanger 23. Thereby, the frost attached to the outdoor heat exchanger 23 can be melted. On the other hand, the indoor unit 4 is heated by the high-temperature and high-pressure gas refrigerant branched at the branch point A1 and flowing into the indoor heat exchanger 41, as in the normal heating operation.

  At this time, since the outdoor heat exchanger 23 does not function as an evaporator, the amount of heat consumed by the outdoor heat exchanger 23 and the indoor heat exchanger 41 is supplied from the electromagnetic induction heating units 6A1 and 6A2. Also at this time, the heating amounts of the electromagnetic induction heating units 6A1 and 6A2 are adjusted so that the return pipe temperature sensor 39 has a predetermined temperature.

[Second Embodiment]
The air conditioner according to the second embodiment of the present invention also has substantially the same configuration as that of the air conditioner 1 of the first embodiment shown in FIG. 1, and the air conditioner of the second embodiment is the first. A different point from the air conditioning apparatus of embodiment is the structure of an electromagnetic induction heating unit.

  FIG. 6 is a conceptual diagram for explaining the configuration of the electromagnetic induction heating unit 6B of the second embodiment. The return pipe 3F shown in FIG. 6 has the same configuration as the return pipe 3F shown in FIG. And also in 2nd Embodiment, the electromagnetic induction heating unit 6B is provided in the return piping 3F similarly to 1st Embodiment. However, in the first embodiment, two electromagnetic induction heating units 6A1 and 6A2 are provided. In the second embodiment, only one electromagnetic induction heating unit 6B is provided in the return pipe 3F.

  An electromagnetic induction heating unit 6B is attached to the entire portion of the return pipe 3F, which is composed of the two straight pipe portions 3F1 and 3F3 and the U-shaped curved pipe portion 3F2, so that it can be inserted and removed in the direction of the arrow Dir1. Yes. Therefore, the electromagnetic induction heating unit 6B includes a magnetic body Co1 having a substantially elliptic opening CA in a plan view and an electromagnetic induction coil 68 wound around the magnetic body Co1. The electromagnetic induction heating unit 6B is supplied with electric power from the high frequency power source So. Thus, since the electromagnetic induction coil 68 of the electromagnetic induction heating unit 6B can be detachably attached to the return pipe 3F, maintenance can be easily performed. Further, since the magnetic body Co1 can be inserted and removed together with the electromagnetic induction coil 68, the maintenance is further facilitated.

  In the electromagnetic induction heating unit 6B of FIG. 6, the magnetic body Co1 is heated so that the magnetic body Co1 is provided in thermal contact with the two straight pipe portions 3F1 and 3F3 of the return pipe 3F. In order to increase the effect of heat conduction, it is preferable that the contact area between the magnetic body Co1 and the straight pipe portions 3F1 and 3F3 is large. Therefore, the opening CA is formed and arranged so as to circumscribe the straight pipe portions 3F1 and 3F3. Yes. In order to increase the efficiency of heat conduction, a metal having high heat conductivity may be fitted into the opening CA of the magnetic body Co1.

  Regarding the temperature of the refrigerant heated by the electromagnetic induction heating unit 6B, when the detection result by the return pipe temperature sensor 39 is below the target temperature range or above the target temperature range with respect to the target temperature range, the output of the high frequency power source So The controller 11 controls the same as in the first embodiment. In the electromagnetic induction heating unit 6B of the second embodiment, since the two straight pipe portions 3F1 and 3F3 are heated by one unit, the heating amount is adjusted for each of the straight pipe portions 3F1 and 3F3 as in the first embodiment. I can't. However, since one electromagnetic induction heating unit 6B can be omitted, the cost can be reduced. In addition, the heating amount of the two straight pipe portions 3F1 and 3F3 can be made different by changing the contact area with the magnetic body Co1 for each of the straight pipe portions 3F1 and 3F3.

  The refrigerant flowing through the return pipe 3F flows from the left and flows through the straight pipe portion 3F1 downward from the inlet of the straight pipe portion 3F1 as indicated by an arrow Fl. Then, suddenly it flows upwards a U-turn at the bending tube portion 3F2. When the flow direction changes in the curved pipe portion 3F2, the refrigerant is agitated due to the density difference between the gas refrigerant and the liquid refrigerant. Thereby, it can suppress that the ratio of the liquid refrigerant which contacts the pipe inner surface of straight pipe part 3F3 reduces, and can prevent that the efficiency of heat transfer falls in straight pipe part 3F3 rather than straight pipe part 3F1.

[Third Embodiment]
The air conditioner according to the third embodiment of the present invention also has the same configuration as that of the air conditioner 1 of the first embodiment shown in FIG. 1 except for the periphery of the electromagnetic induction heating unit. First, the air conditioner of 3rd Embodiment differs from the air conditioner of 1st Embodiment in the structure of an electromagnetic induction heating unit, and the air conditioner of 3rd Embodiment is the air conditioner of 2nd Embodiment. The same electromagnetic induction heating unit 6B is used. The difference between the third embodiment and the first embodiment is the shape of the return pipe 3F.

  FIG. 7 is a conceptual diagram showing the electromagnetic induction heating unit 6B of the third embodiment and its peripheral structure. In FIG. 7, the upper part of the figure coincides with the upper part of the air conditioner. That is, the return pipe 3F in FIG. 7 includes straight pipe portions 3F4 and 3F6 arranged horizontally, and a U-shaped curved pipe portion 3F5 that connects two straight pipe portions 3F4 and 3F6 arranged vertically. Have.

  The electromagnetic induction heating unit 6B can be inserted / removed in the direction (horizontal direction) of the arrow Dir2 with respect to the entire portion composed of the two straight pipe portions 3F4, 3F6 and the U-shaped curved pipe portion 3F5 in the return pipe 3F. It is attached to. Therefore, the electromagnetic induction heating unit 6B includes a magnetic body Co1 having a substantially elliptic opening CA in a plan view and an electromagnetic induction coil 68 wound around the magnetic body Co1, and supplies power from the high-frequency power source So. The points received and the effects thereof are also as described in the second embodiment.

  In the electromagnetic induction heating unit 6B of FIG. 7, the magnetic body Co1 is heated so that the magnetic body Co1 is provided in thermal contact with the two straight pipe portions 3F4 and 3F6 of the return pipe 3F. This is the same as in the second embodiment. In order to increase the effect of heat conduction, it is preferable that the contact area between the magnetic body Co1 and the straight pipe portions 3F4 and 3F6 is large. Therefore, the magnetic body Co1 is formed and attached so as to circumscribe the straight pipe portions 3F4 and 3F6. ing.

  As indicated by an arrow Fl, the refrigerant flowing through the return pipe 3F flows from the top to the bottom toward the inlet of the straight pipe portion 3F4, and changes the flow direction in the horizontal direction at the straight pipe portion 3F4. The upward coolant flows toward the bending tube portion 3F5 from the straight pipe portion 3F4. At this time, in the straight pipe portion 3F4, the liquid layer (liquid refrigerant) is formed below, and the heated gas layer (gas refrigerant) flows upward, so that a smooth flow can be configured. Further, since the refrigerant gasified by being brought into thermal contact with and heated by the pipe inner surface of the straight pipe portion 3F4 is stirred with the liquid refrigerant in the curved pipe portion 3F5, the refrigerant is thermally applied to the pipe inner surface of the straight pipe portion 3F6. It is possible to prevent a large amount of gas refrigerant from being unevenly distributed in the portion in contact with the pipe, and to prevent the heating efficiency in the straight pipe portion 3F6 from being significantly reduced as compared to the straight pipe portion 3F4.

[Fourth Embodiment]
The air conditioner according to the fourth embodiment of the present invention also has substantially the same configuration as that of the air conditioner 1 of the first embodiment shown in FIG. 1, and the air conditioner of the fourth embodiment is the first. A different point from the air conditioning apparatus of embodiment is the structure of an electromagnetic induction heating unit.

  8 and 9 are conceptual diagrams for explaining the configuration of the electromagnetic induction heating unit 6C and the return pipe 3F of the fourth embodiment. The return pipe 3F shown in FIGS. 8 and 9 is the same pipe as the pipe shown in FIG. And also in 4th Embodiment, 6C of electromagnetic induction heating units are provided in the return piping 3F similarly to 1st Embodiment. However, in the first embodiment, two electromagnetic induction heating units 6A1 and 6A2 are provided. In the fourth embodiment, only one electromagnetic induction heating unit 6C is provided in the return pipe 3F.

  The electromagnetic induction heating unit 6C includes separable magnetic bodies Co2 and Co3, and two electromagnetic induction coils 68C1 and 68C2 arranged with the magnetic bodies Co2 and Co3 interposed therebetween. The coil of the electromagnetic induction heating unit 6C is detachably mounted in the direction of the arrow Dir3 with respect to the entire portion composed of the two straight pipe portions 3F7, 3F9 and the U-shaped curved pipe portion 3F8 in the return pipe 3F. Has been. The direction of the arrow Dir3 is a direction along a plane including the straight pipe portions 3F7, 3F9 and the curved pipe portion 3F8. On the other hand, after the magnetic induction coils 68C1 and 68C2 are pulled out, the magnetic bodies Co2 and Co3 can be separated from the return pipe 3F by being divided in the directions of arrows Dir4 and Dir5. The straight pipe portions 3F7 and 3F9 are supported by the air conditioner by the support member SP, and the position in the air conditioner does not change even if the magnetic bodies Co2 and Co3 are removed. The point of receiving power supply from the high-frequency power source So and the effects thereof are also as described in the second embodiment.

  In the electromagnetic induction heating unit 6C shown in FIGS. 7 and 8, since the magnetic bodies Co2 and Co3 are heated, the magnetic bodies Co2 and Co3 are in thermal contact with the two straight pipe portions 3F7 and 3F9 of the return pipe 3F. Is provided. In order to increase the effect of heat conduction, it is preferable that the contact area between the magnetic bodies Co2 and Co3 and the straight pipe portions 3F7 and 3F9 is large. Therefore, the magnetic bodies Co2 and Co3 cover the straight pipe portions 3F7 and 3F9. Formed and attached. Therefore, as shown in FIG. 8, the magnetic bodies Co2 and Co3 have a larger width in plan view than the distance between the straight pipe portions 3F7 and 3F9 arranged in parallel to the diameter of the straight pipe portions 3F7 and 3F9. Have. In addition, as shown in FIG. 9, the magnetic bodies Co2 and Co3 extend not only between the straight pipe portions 3F7 and 3F9 where the magnetic flux density becomes high, but also to the surface far from the adjacent portions of the magnetic bodies Co2 and Co3. ing. This is a structure suitable for transferring heat to the entire surfaces of the straight pipe portions 3F7 and 3F9 through the magnetic bodies Co2 and Co3. This is because if the heat generation amount is the same, heat transfer to the refrigerant becomes easier when the entire pipe is set to the same temperature than when the local portions of the straight pipe portions 3F7 and 3F9 are heated.

  Regarding the temperature of the refrigerant heated by the electromagnetic induction heating unit 6C, when the detection result by the return pipe temperature sensor 39 is below the target temperature range or above the target temperature range with respect to the target temperature range, the output of the high frequency power source So The controller 11 controls the same as in the second embodiment. In the second embodiment, the amount of heating of the two straight pipe portions 3F7, 3F9 can be made different by making the contact areas with the magnetic bodies Co2, Co3 different for each of the straight pipe portions 3F7, 3F9. It is the same.

  The refrigerant flowing through the return pipe 3F is agitated by the curved pipe portion 3F8, as in the second embodiment. Further, the return pipe 3F can be arranged so that the straight pipe portion is horizontal as in the third embodiment, and the effect when the return pipe 3F is formed in this way is the same as that of the third embodiment.

[Fifth Embodiment]
The air conditioner according to the fifth embodiment of the present invention also has the same configuration as that of the air conditioner 1 of the first embodiment shown in FIG. 1 except for the periphery of the electromagnetic induction heating unit. Basically, in the fifth embodiment, an electromagnetic induction heating unit 6D having the same configuration as that of the fourth embodiment is used. Further, the difference between the fifth embodiment and the first embodiment is the shape of the return pipe 3F.

  FIG. 10 is a conceptual diagram showing an electromagnetic induction heating unit DB and its peripheral structure according to the fifth embodiment. As shown in FIG. 10, the return pipe 3F in FIG. 10 includes three straight pipe portions 3F10, 3F12, 3F14 and two U-shaped curved pipe portions 3F11, 3F13 connecting them. Therefore, as shown in FIG. 10, the magnetic body Co4 has a width that extends over the three straight pipe portions 3F10, 3F12, and 3F14 in a plan view. Since this magnetic body Co4 is heated at three locations of the straight pipe portions 3F10, 3F12, and 3F14, it is easy to heat to a high temperature. Further, since stirring is performed at two locations of the two bent tube portions 3F11 and 3F13, the heating unevenness of the refrigerant is reduced as compared with the case of stirring at one location. Further, the return pipe 3F can be arranged so that the straight pipe portion is horizontal as in the third embodiment, and the effect when the return pipe 3F is formed in this way is the same as that of the third embodiment.

[Sixth Embodiment]
The air conditioning apparatus according to the sixth embodiment of the present invention has the same configuration as that of any one of the first to fifth embodiments except for the internal structure of the curved pipe portion of the return pipe. ing. In each of the above embodiments, the inner peripheral surfaces of the bending tube portions 3F2, 3F5, 3F8, 3F11, and 3F13 are smooth surfaces without unevenness. In 6th Embodiment, as shown to Fig.11 (a) and FIG.11 (b), the convex part 101 is provided in the bending tube part 3F15, and the convex part 101 is used as a stirring member. FIG. 11A is a side sectional view of the bending tube portion 3F15, and FIG. 11B is a sectional view taken along line XX of FIG. Although the curved tube portion 3F15 in FIG. 11A shows a case where one convex portion 101 is provided as a stirring member, a plurality of locations may be provided. Further, the place where the stirring member is provided is not limited to the intermediate portion outside the curved pipe portion 3F15 having a large curvature radius, and may be, for example, the side having a small curvature radius. In addition, when a plurality of stirring members can be provided, for example, by arranging convex portions in a staggered manner, the laminar flow that flows along the inner peripheral surface is provided over the whole so as to be stirred in any place. preferable. Further, the stirring member is not limited to the convex portion, and may be a concave portion, and is not integral with the inner wall of the curved tube portion 3F15 unlike the convex portion 101, and the mesh 102 shown in FIG. However, it is preferable to use a member such as the net 102 that has a small pressure loss of the refrigerant.

<Modification>
(A)
In the first to sixth embodiments, the case where the return pipe 3F is provided with the electromagnetic induction heating units 6A1, 6A2, 6B, 6C, and 6D and the refrigerant is heated in the return pipe 3F by electromagnetic induction has been described. The location of overheating due to electromagnetic induction is not limited to the location where the return pipe 3F of the refrigeration circuit is located, and may be another location. In the case of heating by electromagnetic induction at another location, a curved tube portion or a straight tube portion for attaching the electromagnetic induction heating unit is provided at that location.

  (B) In the first to sixth embodiments, the case where the bending tube portions 3F2, 3F5, 3F8, 3F11, and 3F13 are U-shaped has been described. The U-tube is preferable because it is easy to manufacture and has a high stirring effect, but the shape of the curved tube portion is not limited to the U-shape. For example, it may be L-shaped or may be combined with the L-shape to form a U-shape. Further, for example, the curved pipe portions 3F2, 3F5, 3F8, 3F11, and 3F13 are arranged so that the straight pipe portions 3F1, 3F4, 3F7, and 3F10 and the straight pipe portions 3F3, 3F6, 3F9, 3F12, and 3F14 are arranged at the twisted positions. It may be curved.

<Features>
(1)
The air conditioner 1 (refrigeration apparatus) includes a straight pipe portion 3F1, 3F4, 3F7, 3F10 (first extending portion), a straight pipe portion 3F3, 3F6, 3F9, 3F12, 3F14 (second pipe) on a return pipe 3F (refrigerant pipe). Extending portion) and curved tube portions 3F2, 3F5, 3F8, 3F11, 3F13 and electromagnetic induction heating units 6A1, 6A2, 6B, 6C, 6D. For example, in the bending tube portion 3F2, the boundary with the straight tube portion 3F1 is an inlet of the bending tube portion 3F2, and the boundary with the straight tube portion 3F3 is an outlet of the bending tube portion 3F2. Here, the boundary is the end of the straight pipe portions 3F1 and 3F3 and is where the pipe starts to bend.

  For example, the electromagnetic induction heating unit 6B of the second embodiment is a straight pipe that is a member that is in thermal contact with the refrigerant passing through the straight pipe portion 3F1 (first extending portion) and the straight pipe portion 3F3 (second extending portion). the parts 3F1 and straight pipe section 3F3, are indirectly heated through the magnetic Co1. In this case, if the magnetic body Co1 is removed and the straight pipe portions 3F1 and 3F3 are made of a magnetic material, the straight pipe portions 3F1 and 3F3 become members that are directly heated by the electromagnetic induction heating unit. Here, the case where the first extending portion and the second extending portion are straight pipe portions is shown, and it is preferable that the first extending portion and the second extending portion extend linearly in terms of performance, cost, handling, etc., but they do not necessarily extend linearly. It is not an essential requirement.

  For example, if the refrigerant that has been heated by the straight pipe portion 3F1 (first extending portion) and becomes a gas refrigerant flows along the tube wall of the straight pipe portion 3F3 (second extending portion) as it is, the straight pipe portion 3F3 A heat transfer rate will fall and heating efficiency will fall. Therefore, the laminar flow heated by the straight pipe portion 3F1 and having a high gas refrigerant content on the inner peripheral surface of the pipe is stirred by the curve of the curved pipe portion 3F2 using the density difference between the gas refrigerant and the liquid refrigerant. . Thereby, in the straight pipe part 3F3 (second extending part), the straight pipe part 3F3 is brought into thermal contact with the stirred refrigerant and heated again to efficiently heat the refrigerant.

  Thus, for example, after being heated by the straight pipe portion 3F1, it is heated again by the straight pipe portion 3F3 via the curved pipe portion 3F2, but during this time the heated refrigerant is agitated and side by side. The effect of being heated. However, since the pipes such as the straight pipe portions 3F1 and 3F2 and the curved pipe portion 3F2 have this effect, there is no pressure loss that hinders the flow of the refrigerant. A reduction in circuit performance can be prevented.

  In the case of trying to stir only with the pipe, it is preferable that the flow of the refrigerant undergoes a sudden change in the curved pipe portion in order to enhance the stirring effect. For this purpose, it is preferable that the bending tube portion has a U-shaped portion in the connection of the straight tube portion, the bending tube portion, and the straight tube portion. This is because, in the U-shaped portion, the direction of the flow of the incoming refrigerant and the outgoing refrigerant changes so as to be completely reversed.

  The return pipe 3F can be arbitrarily arranged in the vertical and horizontal directions, but the curved pipe portions 3F2, 3F5, 3F8, 3F11, and 3F13 are made to be more than the straight pipe portions 3F3, 3F6, 3F9, 3F12, and 3F14 (second extending portion). When arranged below, the liquid layer of the refrigerant tends to accumulate below the gas layer, so that the liquid layer accumulated below can be heated, resulting in good heating efficiency.

(2)
As shown in the sixth embodiment, the bending tube portion 3F15 includes a convex portion 101 (stirring member) for stirring the refrigerant. Since this convex portion 101 (stirring member) promotes the stirring of the refrigerant by disturbing the flow of the refrigerant in the bending tube portion 3F15, the bending tube portion 3F15 that stirs the gas refrigerant and the liquid refrigerant using a density difference. This stirring is different. Therefore, since a different stirring effect is combined, a higher stirring effect can be obtained.

(3)
The electromagnetic induction coil 68 of the electromagnetic induction heating unit 6B of the second embodiment and the third embodiment includes a straight pipe portion 3F1, 3F4 (first extending portion) extending in parallel and a straight pipe portion 3F3, 3F6 (second From the stretched part) and can be separated along the direction in which they extend. Therefore, this is because the number of coils can be increased by heating a plurality of locations of the straight pipe portions 3F1, 3F4 (first extending portion) and the straight pipe portions 3F3, 3F6 (second extending portion) with one electromagnetic induction coil 68. And the high-frequency power source So can be reduced, and the cost can be reduced. In addition, maintenance can be performed in a state where the electromagnetic induction heating unit 6B is pulled out and separated from the return pipe 3F.

  Further, the electromagnetic induction coils 68C1, 68C2, 68D1, etc. of the electromagnetic induction heating units 6C, 6D of the fourth embodiment and the fifth embodiment are arranged across the surface including the straight pipe portions 3F7, 3F9, 3F10, 3F12, 3F14. Is done. Further, the set of electromagnetic induction coils 68C1 and 68C2 and the set of electromagnetic induction coils 68D1 face each other in a direction penetrating this surface. Therefore, it is easy to remove and maintain. In addition, since heating can be performed at a plurality of locations with a single high-frequency power source So, costs can be reduced.

2 Outdoor unit 4 Indoor unit 6A1, 6A2, 6B, 6C, 6D Electromagnetic induction heating unit 10 Refrigerant circuit 11 Control unit 21 Compressor 3F Return pipe 3F1, 3F4, 3F7, 3F10 Straight pipe part (first extending part)
3F3, 3F6, 3F9, 3F12, 3F14 Straight pipe part (second extending part)
3F2, 3F5, 3F8, 3F11, 3F13 Curved tube portion 68, 68C1, 68C2, 68D1 Electromagnetic induction coils 101, 102 Stirring member

JP-A-11-2111195 JP-A-8-326997

Claims (7)

A curved pipe portion (3F2, 3F5, 3F8, 3F11, 3F13) having a refrigerant inlet and outlet and curved between the inlet and the outlet, and a first extending portion extending from the inlet of the curved pipe portion (3F1, 3F4, 3F7, 3F10) and a refrigerant pipe (3F) having a second extending portion (3F3, 3F6, 3F9, 3F12, 3F14) extending from the outlet of the bent tube portion;
Electromagnetic induction heating unit (6A1, 6A2, 6B, 6C, 6D) for directly or indirectly heating a member that makes thermal contact with the refrigerant passing through at least the first extending portion and the second extending portion by electromagnetic induction A refrigeration apparatus comprising:   Member for the thermal contact is the refrigerant pipe (3F), the refrigeration apparatus according to claim 1.   In the refrigerant pipe, the first extending portion includes a first straight pipe portion (3F1, 3F4, 3F7, 3F10), and the second extending portion is a second straight pipe portion (3F3, 3F6, 3F9, 3F12, 3F14). The refrigeration apparatus according to claim 1, wherein the curved tube portion includes at least one U-shaped portion.   The refrigeration apparatus according to any one of claims 1 to 3, wherein the curved pipe portion includes an agitating member (101, 102) for agitating the refrigerant in an internal curved portion. The first extending portion and the second extending portion extend in parallel,
The electromagnetic induction heating unit includes an electromagnetic induction coil (68, 68C1, 68C2, 68D1) which is pulled out along the direction in which the first extending portion and the second extending portion extend to be separable from the refrigerant pipe. The refrigeration apparatus according to any one of claims 1 to 4, further comprising:   The electromagnetic induction heating unit is arranged to face each other across the first extending portion and the second extending portion in a direction penetrating the surface including the first extending portion and the second extending portion. The refrigerating apparatus according to any one of claims 1 to 4, comprising an electromagnetic induction coil (68C1, 68C2, 68D1).   The refrigeration apparatus according to any one of claims 1 to 6, wherein the refrigerant pipe has the curved pipe portion disposed below the second extending portion.

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