WO2010032414A1

WO2010032414A1 - Coolant heating device

Info

Publication number: WO2010032414A1
Application number: PCT/JP2009/004555
Authority: WO
Inventors: 若嶋真博; 下田順一
Original assignee: ダイキン工業株式会社
Priority date: 2008-09-17
Filing date: 2009-09-14
Publication date: 2010-03-25
Also published as: JP2011247428A

Abstract

Provided is a coolant heating device which can improve the heat transmission from an external pipe to an internal pipe. The coolant heating device (30) includes: the internal pipe (31) through which coolant flows, the external pipe (32), and an induction heating coil (33). The external pipe (32) surrounds the internal pipe (31) and is made from a magnetic material. The induction heating coil (33) surrounds the external pipe (32) and inductively heats the external pipe (32). A heat transmission agent (43) having a higher thermal conductivity than the air is arranged between the external circumferential surface (31a) of the internal pipe (31) and the internal circumferential surface (32b) of the external pipe (32).

Description

Refrigerant heating device

The present invention relates to a refrigerant heating device that heats a refrigerant flowing through a refrigerant pipe.

Conventionally, there are various methods for heating the refrigerant in the refrigerant circuit, but an induction heater (hereinafter referred to as IH heater) is convenient in that the refrigerant can be rapidly heated using induction heating.
Such an IH heater for heating a refrigerant can induce induction heating by exciting a pipe through which the refrigerant flows or a magnetic material inside and outside the pipe by an induction heating coil, thereby heating the refrigerant in the pipe. It is.

Here, copper is usually adopted as the material of the piping constituting the refrigerant circuit in consideration of aspects such as thermal conductivity, workability, or material cost. However, as the material of the pipe heated by the IH heater, it is preferable to employ a magnetic material such as stainless steel in order to efficiently perform electromagnetic induction heating.
Therefore, like the IH heater described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-174054), magnetic coating or powder is coated on the outer periphery of the copper tube so that induction heating can be efficiently performed even for the copper tube. I have to.

Here, in order to further improve the efficiency of induction heating, it is conceivable to employ a stainless steel pipe as a pipe through which the refrigerant flows inside the IH heater. In this case, the stainless steel pipe heated by the IH heater and other refrigerant circuits are considered. Since the material is different from that of the copper pipe constituting the wire, it is necessary to braze different pipes, and there is a possibility that defects (such as cracks) occur in the manufacturing cost and the brazed part.
It is also possible to insert a copper tube inside the stainless steel tube to make a double tube, but even if a copper tube having the same outer diameter is inserted into the inner diameter of the stainless steel tube, the stainless steel tube and the copper tube are good. There is a problem that it is difficult to obtain a proper contact state. For this reason, it is also difficult to improve the heat transfer from the stainless steel tube heated by induction to the copper tube.
The subject of this invention is providing the refrigerant | coolant heating apparatus which can improve the heat transfer from an outer tube | pipe to an inner tube | pipe.

The refrigerant heating device of the first invention includes an inner tube through which a refrigerant flows, an outer tube, and an induction heating coil. The outer tube surrounds the inner tube and is made of a magnetic material. The induction heating coil surrounds the periphery of the outer tube and induction-heats the outer tube. A heat transfer agent having a higher thermal conductivity than air is disposed between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube.
Here, since a heat transfer agent having a higher thermal conductivity than air is disposed between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube, the outer tube heated by induction is transferred from the outer tube to the inner tube. As a result, the heat transfer to the refrigerant is improved.

The refrigerant heating device of the second invention is the refrigerant heating device of the first invention, and the heat transfer agent is in a gel form.
Here, since the heat transfer agent is in a gel form, it is easy to form a heat transfer agent layer having a desired film thickness simply by applying the gel heat transfer agent to the outer peripheral surface of the inner tube or the inner peripheral surface of the outer tube. Can be secured.

The refrigerant heating device of the third invention is the refrigerant heating device of the first invention or the second invention, and the heat transfer agent is a silicone resin.
Here, by using silicon resin as the heat transfer agent, the thermal conductivity and adhesion between the inner tube and the outer tube are good.

The refrigerant heating device of the fourth invention is the refrigerant heating device of the first invention, wherein irregularities are formed on the inner peripheral surface of the outer tube and / or the outer peripheral surface of the inner tube.
Here, since the irregularities are formed on the inner peripheral surface of the outer tube and / or the outer peripheral surface of the inner tube, the contact area of both the tubes increases, and heat transfer from the outer tube to the inner tube that is induction-heated, As a result, heat transfer to the refrigerant is improved.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a refrigerant heating apparatus comprising: a covering step of covering an outer peripheral surface of an inner tube with a heat transfer agent; an inserting step of inserting the inner tube into the outer tube; Expansion process for expanding the pipe.
Here, after the outer peripheral surface of the inner tube is coated with a heat transfer agent, it is inserted into the outer tube and expanded, so that the heat transfer from the outer tube that is induction-heated to the inner tube is improved. Heat transfer is improved. Moreover, it is easy to manufacture.

According to the first invention, since the heat transfer agent having a higher thermal conductivity than air is disposed between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube, the outer tube that is induction-heated The heat transfer from the pipe to the inner pipe is improved, and as a result, the heat transfer to the refrigerant is improved.
According to the second invention, it is possible to easily secure a layer of the heat transfer agent having a desired film thickness.
According to the third invention, thermal conductivity and adhesion between the inner tube and the outer tube are improved.
According to the fourth aspect of the present invention, the contact area between the two tubes is increased, and heat transfer from the outer tube to the inner tube that is induction-heated, and thus heat transfer to the refrigerant, is improved.
According to the fifth aspect of the invention, the heat transfer from the outer tube that is induction-heated to the inner tube is improved, and as a result, the heat transfer to the refrigerant is improved. Moreover, it is easy to manufacture.

The circuit diagram of the air conditioner to which the IH heater assembly concerning the embodiment of the present invention was attached. The expansion perspective view of the machine room part of the outdoor unit of FIG. FIG. 2 is a front view of the IH heater assembly of FIG. 1. FIG. 2 is a cross-sectional view of the IH heater assembly of FIG. 1. Cross-sectional explanatory drawing which shows the insertion process in the manufacturing method of the IH heater assembly of FIG. Cross-sectional explanatory drawing which shows the pipe expansion process in the manufacturing method of the IH heater assembly of FIG. Sectional explanatory drawing which shows the bobbin mounting process in the manufacturing method of the IH heater assembly of FIG. The expanded sectional view of the contact surface of the inner tube | pipe and outer tube | pipe of FIG. The expanded sectional view which shows the coating | coated process in the manufacturing method of the IH heater assembly of FIG. The expanded sectional view which shows the insertion process in the manufacturing method of the IH heater assembly of FIG. The expanded sectional view which shows the pipe expansion process in the manufacturing method of the IH heater assembly of FIG.

Next, an embodiment of the refrigerant heating device of the present invention will be described with reference to the drawings.
Embodiment
<Basic configuration>
In the air conditioner 1 including the refrigerant heating device 30 (hereinafter referred to as the IH heater assembly 30) shown in FIG. 1, the outdoor unit 2 and the indoor unit 4 are connected to the liquid refrigerant communication pipe 6 and the gas refrigerant as shown in FIG. A refrigerant circuit 11 configured to be connected by a communication pipe 7 is provided. Each refrigerant pipe of the refrigerant circuit 11 is usually made of copper.
As shown in FIGS. 1 and 2, the refrigerant circuit 11 includes, in the outdoor unit 2, a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, an expansion valve 24 including an electronic expansion valve with adjustable throttle, An IH heater assembly 30 and an accumulator 25 are provided. In addition, the refrigerant circuit 11 includes an indoor heat exchanger 26 and the like inside the indoor unit 4 as shown in FIG. In addition, the four-way selector valve 22 has shown the switching connection state in the case of performing heating operation in FIG.

Here, the refrigerant flowing in the refrigerant circuit 11 is not particularly limited in the present invention, and is, for example, HFC (R410A or the like), carbon dioxide refrigerant, or the like.
As shown in FIG. 1, the refrigerant circuit 11 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, and a suction pipe G. ing.
Hereinafter, the connection state of each refrigerant pipe will be described in the order of the flow path where the refrigerant discharged from the compressor 21 flows out and is sucked into the compressor 21 again.
The discharge pipe A connects the discharge side of the compressor 21 and the four-way switching valve 22.
The indoor side gas pipe B connects the four-way switching valve 22 and the gas side of the indoor heat exchanger 26.
The indoor side liquid pipe C connects the liquid side of the indoor heat exchanger 26 and the expansion valve 24. Here, the indoor side liquid pipe C includes a liquid refrigerant communication pipe 6 that connects the outdoor unit 2 and the indoor unit 4.

The outdoor liquid pipe D connects the expansion valve 24 and the liquid side of the outdoor heat exchanger 23.
The outdoor gas pipe E connects the gas side of the outdoor heat exchanger 23 and the four-way switching valve 22.
The accumulator pipe F connects the four-way switching valve 22 and the accumulator 25.
The suction pipe G connects the accumulator 25 and the suction side of the compressor 21.
In this way, the refrigerant circuit 11 is configured, and heating operation can be performed by circulating the refrigerant in the above-described direction. The cooling operation can also be performed by switching the connection state of the four-way switching valve 22.
In the middle of the accumulator tube F, an IH heater assembly 30 described later is connected by brazing.
<Configuration of IH heater assembly 30>
As shown in FIGS. 3 to 4 and FIG. 8, the IH heater assembly 30 is an IH heater composed of a double tube, and includes an inner tube 31, an outer tube 32, a silicon resin 43, an induction heating coil 33, A bobbin 34, a pair of lids 35, a pair of nuts 36, a plurality of ferrite blocks 37, a ferrite holder 38, and a sheet metal cover 39 are provided.

The inner pipe 31 is made of copper, which is the same material as the refrigerant pipe 5, and the refrigerant flows through the inner pipe 31.
The outer tube 32 is made of stainless steel, which is a magnetic material, and is disposed around the inner tube 31. Specifically, by expanding the inner tube 31, the outer peripheral surface of the inner tube 31 and the inner peripheral surface of the outer tube are in close contact with each other.
The material of the outer tube 32 is not limited to stainless steel. For example, an alloy containing a conductor such as iron, copper, aluminum, chromium, nickel and at least two metals selected from these groups. Etc. Examples of stainless steel include at least one of ferrite and martensite, or a combination thereof.

As shown in FIG. 8, the silicon resin 43 is disposed between the outer peripheral surface 31 a of the inner tube 31 and the inner peripheral surface 32 b of the outer tube 32. The silicon resin 43 is the heat transfer agent of the present invention and has a higher thermal conductivity than air. Therefore, heat transfer from the outer tube 32 that is induction-heated to the inner tube 31 is improved, and as a result, heat transfer to the refrigerant H is improved.
8 is a gel-like silicon resin with good adhesion. Therefore, by simply applying the gel-like silicon resin 43 to the outer peripheral surface 31a of the inner tube 31 or the inner peripheral surface 32b of the outer tube 32, a layer of the silicon resin 43 having a desired film thickness can be easily secured. The gel-like silicon resin 43 can be applied by various methods, but is applied by, for example, a brush or a roller.
Furthermore, by using the silicon resin 43 as the heat transfer agent, the thermal conductivity and adhesion between the inner tube 31 and the outer tube 32 are good.

Moreover, since the recessed part 32c and the convex part 31b are each formed in the inner peripheral surface 32b of the outer tube | pipe 32 and the outer peripheral surface 31a of the inner tube | pipe 31, the contact area of both tubes increases and the outer tube | pipe 32 induction-heated. The heat transfer from the pipe to the inner pipe 31 and thus the heat transfer to the refrigerant is improved.
The induction heating coil 33 surrounds the outer tube 32 and induction-heats the outer tube 32. The induction heating coil 33 is arranged so as to surround the outer periphery of the outer tube 32 in a state of being wound around a bobbin 34 which is a separate member from the outer tube 32.
The bobbin 34 is a cylindrical member whose both ends are open, and the induction heating coil 33 is wound around the side peripheral surface thereof.
The pair of lids 35 has an opening 35 a at the center and is fitted to the outer periphery of the outer tube 32. In addition, the pair of lids 35 is fixed from both the upper and lower sides by a C-shaped ferrite holder 38 to be described later while being attached to the bobbin 34.

The pair of nuts 36 is a combination of the bobbin 34, the lid 35, the ferrite holder 38, and the nut 36 of the IH heater assembly 30 in advance by being screwed into male screw portions 32a formed on the outer periphery near both ends of the outer tube 32. Is fixed to the outer periphery of the outer tube 32.
The plurality of ferrite blocks 37 are mounted side by side on a C-shaped ferrite holder 38 in order to reduce leakage magnetic flux to the outside of the sheet metal cover 39 of the IH heater assembly 30. The ferrite holder 38 is attached from the outside of the induction heating coil 33 from the four sides of the bobbin 34.
As shown in FIGS. 2 and 4, the sheet metal cover 39 is a cover made of a thin metal plate and is screwed to the outside of the ferrite holder 38. The sheet metal cover 39 has a cylindrical shape or a polygonal shape so as to surround the cylindrical bobbin 34, and has an integrated shape or a shape divided into two or more.

Thereby, since the inner pipe 31 is made of the same kind of copper as the other refrigerant pipes F, the inner pipe 31 and the refrigerant pipe F can be easily joined (manufactured easily). Moreover, efficient induction heating is possible by the outer tube 32 made of a magnetic material such as stainless steel.
Moreover, since the structure which supports the bobbin 34 with the induction heating coil 33 wound around the thick outer tube 32 is adopted, the overall strength of the IH heater assembly 30 is improved.
As described above, the IH heater assembly 30 is provided in the middle of the portion of the accumulator pipe F that connects the four-way switching valve 22 and the accumulator 25, so that as shown in FIG. By the IH heater assembly 30 that receives the high-frequency alternating current from the high-frequency power source 60 via the intake air, the intake gas refrigerant that is directed from the four-way switching valve 22 to the accumulator 25 can be warmed, and the heating capacity can be improved.

In addition, when the heating operation is started, the compressor 21 may not be sufficiently warmed. Here, the IH heater assembly 30 generates heat, so that the gas from the four-way switching valve 22 toward the accumulator 25 is generated. The refrigerant can be heated, and the lack of capacity at the start-up can be compensated.
Further, when the four-way switching valve 22 is switched to the state for cooling operation and the defrost operation for removing the frost attached to the outdoor heat exchanger 23 is performed, the gas refrigerant heated through the IH heater assembly 30 is used. Can be further compressed by the compressor 21, so that the temperature of the hot gas discharged from the compressor 21 can be increased. 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.
<Method for Manufacturing IH Heater Assembly 30>
When manufacturing the IH heater assembly 30 of this embodiment, first, as shown in FIG. 9, the gel-like silicon resin 43 is applied to the outer peripheral surface 31a of the inner tube 31 (covering step). In addition, the convex part 31 is previously formed in the area | region where the silicon resin 43 is apply | coated among the outer peripheral surfaces 31a of the inner pipe | tube 31.

Next, as shown in FIG. 5 and FIG. 10, the copper inner pipe 31 constituting a part of the refrigerant pipe of the refrigerant circuit 11 is inserted into the stainless steel outer pipe 32 made of a magnetic material ( Insertion process). The inner diameter of the outer tube 32 is set so as to obtain a clearance between the inner tube 31 and the convex portion 31b of the inner tube 31 and the silicon resin 43 layer.
Then, as shown in FIG. 6 and FIG. 11, the inner pipe 31 is press-fitted into the inner pipe 31 so that the outer diameter of the inner pipe 31 increases. By being enlarged, it fits inside the outer pipe 32 (pipe expansion process). At this time, when the inner tube 31 is expanded, the silicon resin 43 enters the recess 32c of the outer tube 32 by being pressed against the inner periphery 32b of the outer tube 32 in which the recess 32c is previously formed in the inner periphery 32b. Therefore, the silicon resin 43 can completely adhere to the inner peripheral surface 32b of the outer tube 32 in which the concave portion 32c is formed and the outer peripheral surface 31a of the inner tube 31 in which the convex portion 31b is formed, as compared with the case where there is no unevenness. A wide contact area is obtained. Therefore, the heat transfer performance is greatly improved corresponding to a wide contact area.

Thereafter, as shown in FIG. 7, a combination of the bobbin 34, the lid 35, the ferrite holder 38 and the nut 36 of the IH heater assembly 30 in advance is inserted into the outer periphery of the outer tube 32 with the nut 36 loosened, After that, the nut 36 is tightened to the outer tube 32, and is pressed against the C-shaped ring 43 in the inner diameter direction, whereby the bobbin 34 and other main parts are mounted (bobbin mounting step). Thereby, the manufacture of the IH heater assembly 30 is completed.
<Features of the embodiment>
(1)
In the IH heater assembly 30 of the embodiment, a silicon resin 43 is disposed between the outer peripheral surface 31a of the inner tube 31 and the inner peripheral surface 32b of the outer tube 32 as a heat transfer agent having a higher thermal conductivity than air. Therefore, the heat transfer from the outer tube 32 that is induction-heated to the inner tube 31 is improved, and as a result, the heat transfer to the refrigerant H is improved.
(2)
Further, in the present embodiment, by adopting the gel-like silicon resin 43, the gel-like silicon resin 43 is simply applied to the outer peripheral surface 31a of the inner tube 31 or the inner peripheral surface 32b of the outer tube 32. A layer of silicon resin 43 having a thickness can be easily secured.
(3)
Moreover, in the IH heater assembly 30 of the embodiment, by using the silicon resin 43 as the heat transfer agent, the thermal conductivity and adhesion between the inner tube 31 and the outer tube 32 are good.

(4)
Further, in the IH heater assembly 30 of the embodiment, the inner peripheral surface 32b of the outer tube 32 and the outer peripheral surface 31a of the inner tube 31 are respectively formed with the concave portion 32c and the convex portion 31b. As a result, the heat transfer from the outer tube 32 to the inner tube 31 that is induction-heated, and thus the heat transfer to the refrigerant is improved.
(5)
In the manufacturing method of the IH heater assembly 30 of the embodiment, the covering step of covering the outer peripheral surface 31a of the inner tube 31 with the silicon resin 43, the inserting step of inserting the inner tube 31 into the outer tube 32, and the inner tube And a tube expanding step for expanding the tube 31 to a predetermined outer diameter.
Therefore, since the outer peripheral surface 31a of the inner tube 31 is coated with the silicon resin 43 and then inserted into the outer tube 32 to expand the tube, the heat transfer from the outer tube 32 that is induction-heated to the inner tube 31 is improved. , Heat transfer to the refrigerant is improved. Moreover, since both the tubes can be firmly coupled with good adhesion simply by inserting the inner tube 31 into the outer tube 32 and expanding the tube, a process for fixing such as brazing between the two tubes becomes unnecessary after the tube expansion. Is very easy.
<Modification>
(A)
In the above embodiment, the gel-like silicon resin 43 is employed as the heat transfer agent, but the present invention is not limited to this, and various heat transfer agents can be employed. . For example, a silicon resin spray or the like that can spray a liquid silicon resin agent may be used. In this case, the silicon resin agent can be easily sprayed on the outer peripheral surface 31a of the inner tube 31, and a thin film can be used. Thickness can be easily obtained.
(B)
In addition, about the recessed part 32c and the convex part 31b which were formed in the inner peripheral surface 32b of the outer tube | pipe 32 and the outer peripheral surface 31a of the inner tube | pipe 31, respectively, as long as the contact area with the silicon resin 43 can be expanded, various forms The present invention is not particularly limited. Therefore, for example, a plurality of dot-like concave portions and convex portions, or a plurality of grooves and ridges extending continuously in a straight line shape or a spiral shape may be used.

The present invention can be variously applied to the field of refrigerant heating devices for induction heating.
.

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Outdoor unit 4 Indoor unit 6 Liquid refrigerant communication piping 7 Gas refrigerant communication piping 11 Refrigerant circuit 21 Compressor 22 Four-way switching valve 23 Outdoor heat exchanger 24 Expansion valve 25 Accumulator 26 Indoor heat exchanger 30 IH heater assembly (Refrigerant heating device)
31 Inner tube 31a Outer peripheral surface 31b Convex portion 32 Outer tube 32a Male threaded portion 32b Inner peripheral surface 32c Concave 33 Induction heating coil 34 Bobbin 35 Lid 36 Nut 37 Ferrite block
38 Ferrite holder 39 Sheet metal cover 41 Expanded billet 43 Silicon resin (heat transfer agent)
A discharge pipe B indoor side gas pipe C indoor side liquid pipe D outdoor side liquid pipe E outdoor side gas pipe F accumulator pipe G suction pipe

Japanese Patent Laid-Open No. 2001-174054

Claims

An inner pipe (31) through which the refrigerant flows;
Surrounding the inner pipe (31), and an outer pipe (32) made of a magnetic material;
An induction heating coil (33) surrounding the outer tube (32) and for induction heating the outer tube (32);
Between the outer peripheral surface of the inner pipe (31) and the inner peripheral surface of the outer pipe (32), a heat transfer agent (43) having a higher thermal conductivity than air is disposed.
Refrigerant heating device (30).
The heat transfer agent (43) is in a gel form.
The refrigerant heating device (30) according to claim 1.
The heat transfer agent (43) is a silicone resin.
The refrigerant heating device (30) according to claim 1 or 2.
Concavities and convexities are formed on the inner peripheral surface of the outer tube (32) and / or the outer peripheral surface of the inner tube (31).
The refrigerant heating device (30) according to claim 1.
It is a manufacturing method of the refrigerant heating device (30) according to claim 1,
A covering step of covering the outer peripheral surface of the inner pipe (31) with the heat transfer agent (43);
An insertion step of inserting the inner tube (31) into the outer tube (32);
The manufacturing method of a refrigerant heating apparatus (30) including the pipe expansion process which expands the said inner pipe (31) to a predetermined | prescribed outer diameter.