JP2001108311A - Refrigerant heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the heat transfer rate to a refrigerant and to improve a heating efficiency in a refrigerant heater for heating the refrigerant flowing through refrigerant piping. SOLUTION: Heating parts 16a, 16b for heating refrigerant piping 20 to transfer a heat from longitudinally disposed refrigerant piping 20 to a refrigerant are provided in the piping 20 to transfer the heat to a liquid refrigerant at an overall periphery of an inner surface of the piping 20. The parts 16a, 16b are formed of a heating part 16a made at least part of the piping 20 in the longitudinal direction and a coil 16b wound on the part 16a. In this case, the part 16b has a high frequency current generating means 16c connected to the coil 16b so as to supply a high-frequency current to the coil 16b to pass an eddy current into the part 16a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant heating device, and more particularly to a refrigerant heating device attached to a refrigerant pipe so as to heat a refrigerant flowing in the refrigerant pipe.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. Hei 5-223194 discloses this type of refrigerant heating device. This refrigerant heating device is provided in a pipe on the discharge side of the compressor in the refrigerant circuit, and is used as an auxiliary heater or the like during a heating operation.

[0003] This refrigerant heating device is composed of a hollow cylindrical body and a helical heater wire built in the cylindrical body, and is configured such that a refrigerant pipe is passed through the cylindrical body. Then, when electricity is supplied to the heater wire, the heat of the heater wire, which generates heat by electric resistance, is transmitted to the refrigerant via the refrigerant pipe. Further, the refrigerant heating device is incorporated in a refrigerant pipe (hereinafter, horizontal pipe) disposed in a lateral direction between the compressor and the indoor heat exchanger.

[0004] The refrigerant heating device is also used to heat the refrigerant during the defrost operation. However, in the refrigerant heating device, the heat transfer coefficient is low to heat the gas refrigerant, and the refrigerant cannot be quickly heated, so that it has been difficult to efficiently perform the defrost operation.

On the other hand, the present applicant has proposed a refrigerant heating device provided in a liquid pipe as a device capable of increasing the heating efficiency by heating a gas-liquid two-phase refrigerant during a defrost operation. Application has been filed (Japanese Patent Application No. 10
-330304, Japanese Patent Application No. 11-265265).

[0006]

However, even when the gas-liquid two-phase refrigerant is heated as described above, the above-mentioned Japanese Patent Application Laid-Open No. 5-223 is disclosed.
Applying the arrangement described in Japanese Patent No. 194, and providing a refrigerant heating device (51) in the horizontal pipe (50) as shown in FIG.
Near the inlet of the refrigerant heating device (51), the liquid refrigerant (L)
0), which accumulates on the lower side and the upper side becomes the gas refrigerant (G), so that the heat transfer coefficient on the upper side of the horizontal pipe (50) deteriorates. For this reason, it has been difficult to obtain sufficient heating efficiency for the entire apparatus.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a refrigerant heating device for heating a refrigerant flowing in a refrigerant pipe, in which a heat transfer coefficient to the refrigerant is reduced. It is to further increase the heating efficiency.

[0008]

According to the present invention, a refrigerant heating device (16) is provided on a refrigerant pipe (longitudinal pipe) (20) arranged in a vertical direction, so that the refrigerant pipe (20) has an entire inner surface. The heat can be transferred to the liquid refrigerant.

Specifically, a solution taken by the present invention is a refrigerant heating device for heating a refrigerant flowing in a refrigerant pipe (20), wherein the refrigerant pipe (20) transmits heat to the refrigerant. A heating section (16a, 16b) for heating (20) is provided, and the heating section (16a, 16b) is provided in a refrigerant pipe (20) arranged in a vertical direction.

In the above configuration, the heating units (16a, 16b)
Refrigerant piping (20) in which refrigerant flows downward from above, or refrigerant piping in which refrigerant flows downward from above
Although it is possible to provide the refrigerant pipe (20), it is particularly preferable to provide the refrigerant pipe (20) through which the refrigerant flows upward from below.

In the above configuration, the heating section (16a, 1
6b) is configured to include a heat generating portion (16a) made of at least a part of the refrigerant pipe (20) in the longitudinal direction as a magnetic material, and a coil (16b) wound around the heat generating portion (16a). At the same time, a high-frequency current is supplied to the coil (16b) to
It is preferable to provide a high-frequency current generating means (16c) connected to the coil (16b) so as to cause an eddy current to flow in (a), so as to constitute an electromagnetic induction heating type refrigerant heating device.

-Operation- In the above solution, the refrigerant pipe (20) is heated by the heating units (16a, 16b), and the heat of the refrigerant pipe (20) is transmitted to the refrigerant.

When the heating section (16a, 16b) is mounted on a vertical refrigerant pipe (20) in which the refrigerant flows downward from above, a bubble-like gas flows against the flow direction of the refrigerant. Refrigerant
Since (G) is going to rise, turbulence occurs in the refrigerant pipe (20). For this reason, the liquid refrigerant (L) does not unevenly contact a part of the refrigerant pipe (20) but uniformly contacts the entire inner surface of the refrigerant pipe (20), so that a high heat transfer coefficient can be obtained.

When the heating section (16a, 16b) is mounted on a vertical refrigerant pipe (20) in which the refrigerant flows upward from below, as the refrigerant advances to the upper part of the refrigerant heating device (16), When the ratio of the gas refrigerant (G) increases, the gas refrigerant (G) flows at a relatively high speed through the center of the refrigerant pipe (20), while the liquid refrigerant (L) flows inside the refrigerant pipe (20). Flows at low speed in an annular shape while contacting That is, an annular flow is generated inside the refrigerant pipe (20). Therefore, in the portion where the heating section (16a, 16b) is provided in the vertical refrigerant pipe (20), the liquid refrigerant (L) always contacts the entire inner surface of the refrigerant pipe (20).
The heat transfer coefficient is further improved as compared with flowing the refrigerant from above to below.

[0015]

As described above, according to the above-described means, the provision of the heating portions (16a, 16b) in the vertically arranged refrigerant pipes (20) allows the liquid refrigerant (L) to flow through the refrigerant pipes (20). Since the heat transfer coefficient is improved by uniformly contacting the inner surface of the cooling medium, more heat can be given to the refrigerant, and the heating efficiency is improved.

Further, from this, even if the heating temperature of the refrigerant pipe (20) by the heating units (16a, 16b) is set slightly lower, heat can be sufficiently transmitted to the refrigerant, and a high energy saving effect can be obtained. In addition to this, the effect of reducing the amount of heat released to the outside can be obtained.

Further, when the refrigerant heating device (16) is constituted by an electromagnetic induction heating system, the refrigerant pipe (20) can be instantly heated to a high temperature, so that the refrigerant can be more efficiently heated. .

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, this refrigeration system (1)
The air conditioner includes an outdoor unit (1a) and an indoor unit (1b). And the outdoor unit
(1a) Inside compressor (10), outdoor heat exchanger (11) and expansion valve (12)
And an indoor heat exchanger (13) in the indoor unit (1b) are connected in order by a refrigerant pipe (20) made of a copper pipe or the like, thereby forming a refrigerant circuit (21).

The compressor (10) and the two heat exchangers (11, 13) are connected via a four-way switching valve (22) so that a heating operation and a cooling operation can be switched. Figure 1 shows a four-way switching valve
The state where (22) is switched to the heating operation side is shown. At this time, the indoor heat exchanger (13) acts as a condenser, and the outdoor heat exchanger (11) acts as an evaporator. An outdoor blower (14) is provided in the outdoor unit (1a), and an indoor blower (15) is provided in the indoor unit (1b).

In the refrigerant circuit (21), the refrigerant flowing between the expansion valve (12) and the outdoor heat exchanger (11) is heated so as to heat the refrigerant flowing through the refrigerant pipe (20) during the defrost operation. A heater (16), which is an apparatus, is provided. In addition, outdoor heat exchanger (11)
Is provided with a frost sensor (17) for detecting frost on the outdoor heat exchanger (11) during the heating operation.

Outdoor blower (14), indoor blower (15), heater
(16) and the frost formation sensor (17) are connected to the controller (18). When the controller (18) detects the frost formation of the outdoor heat exchanger (11) by the frost sensor (17) during the heating operation, the heater (16) continues the operation of the compressor (10) in the normal cycle.
Is operated to perform the defrost operation.

Next, the configuration of the heater (16) will be described with reference to FIG. This heater (16) is an electromagnetic induction heating type heater. Specifically, the heater (16) is connected to the refrigerant pipe (2
(0) a heating part (16a) formed of a magnetic material;
(16a), and a coil (16b) wound around a heat insulating material (16c).
A high-frequency power supply (16d), which is a high-frequency current generating means, is connected to (16b) so as to supply a high-frequency current and cause an induced current to flow to the heat generating portion (16a).

In this configuration, the heat generating portion (16a) is formed by joining a ferromagnetic cylinder (iron pipe or the like) to a part of the refrigerant pipe (20) or by using a thin ferromagnetic material (iron foil or the like). Refrigerant piping (2
0). And the heating part
(16a) constitutes a part of the refrigerant pipe (20), and at the same time, also serves as a component of the heater (16).

Further, as a feature of the present invention, the heater (16)
The configuration is such that a heating section (16a, 16b) is provided in a refrigerant pipe (20) vertically arranged so that the refrigerant flows upward from below. In this regard, FIG.
Is shown as being provided in the horizontal piping, but FIG. 1 is merely a refrigerant circuit diagram, and naturally does not represent the direction of the refrigerant piping (20).

The electromagnetic induction heating type heater (16)
Generally, the higher the frequency of the high-frequency current used, the higher the heating efficiency can be increased.However, excessive heat generation is not required. A suitable range may be selected in consideration of the above.

-Operation- Next, the operation of the refrigeration system will be described.

At the time of the heating operation shown in FIG.
The refrigerant is compressed in (10). The high-temperature and high-pressure refrigerant exiting the compressor (10) enters the indoor heat exchanger (13), exchanges heat with indoor air, condenses, and is cooled. Warm air is supplied into the room by this heat exchange, and the room is heated.

After the refrigerant enters the expansion valve (12) and is decompressed, it exchanges heat with outdoor air in the outdoor heat exchanger (11) and evaporates.
Return to the compressor. Thereafter, the above heating cycle is repeated.

In this heating operation, the outdoor heat exchanger (11)
When frost forms, frost formation is detected by the frost formation sensor (17),
The defrost operation is started by the controller (18).
At this time, a high-frequency current flows through the coil (16b) of the heater (16), and a high-frequency magnetic field is generated around the high-frequency current. with this,
An eddy current is generated in the heat generating portion (16a) of the refrigerant pipe (20), and the heat generating portion (16a) is instantly heated to a high temperature.
a) is transferred to the refrigerant.

In the defrost operation, the heating cycle remains unchanged.
The operation is performed by continuing the operation of the compressor (10) and the indoor blower (15) and stopping the outdoor blower (14). For this reason, the compressor (10)
Is condensed in the indoor heat exchanger (13), and then decompressed by the expansion valve (12) and supplied to the heater (16) in a gas-liquid two-phase state.

FIG. 3 shows a refrigerant pipe (2) provided with a heater (16).
0) schematically shows the phase state of the refrigerant flowing inside. At the inlet of the two-phase refrigerant to the heater (16), the liquid refrigerant (L) is substantially mixed with the gaseous refrigerant (G) in the form of a bubble, and the liquid refrigerant (L) is almost in contact with the inner surface of the heat generating portion (16a). At the outlet side (upper side) of the heater (16), the refrigerant flows into the heating section
In the process of receiving the heat from (16a) and undergoing a phase change, the gas refrigerant (G) flows through the center of the refrigerant pipe (20) at high speed, and
(L) adheres to the pipe wall and flows, resulting in an annular flow.
As a result, the heat is uniformly transmitted as a whole from the heat generating portion (16a) to the liquid refrigerant (L), so that the heat transfer coefficient is improved.

Therefore, a larger amount of heat is given to the refrigerant, the refrigerant thus efficiently heated is sent into the outdoor heat exchanger (11), and the heat of the refrigerant causes the outdoor heat exchanger (1) to heat the refrigerant.
1) The frost is removed.

In the above description, the outdoor unit (1a) defrosts the outdoor heat exchanger (11) while the heating is continued by operating the indoor blower (15) during the defrost operation. However, during defrost operation, both blowers
(14,15) may be stopped. In that case, the refrigerant is hardly cooled in the indoor heat exchanger (13) and can be quickly heated by the heater (16).

On the other hand, when performing the cooling operation, the four-way switching valve
(22) is switched to the cooling side, and the refrigerant is sent from the compressor (10) to the outdoor heat exchanger (11), the expansion valve (12), and the indoor heat exchanger (13) in this order, so that cold air can be supplied to the room. Become like

-Effects of Embodiment- According to the present embodiment, the heating sections (16a, 16a) are provided in the refrigerant pipe (20) which is arranged vertically and in which the refrigerant flows upward from below.
By providing b), the liquid refrigerant (L) comes into uniform contact with the inner surface of the refrigerant pipe (20) and the heat transfer coefficient is improved, so that more heat can be given to the refrigerant and heating can be performed. Efficiency is improved.

Further, even if the heating temperature of the heat generating portion (16a) of the refrigerant pipe (20) is set lower, heat can be efficiently transmitted to the refrigerant and the refrigerant can be sufficiently heated, so that the energy saving effect is high. Moreover, the effect of reducing the amount of heat released to the outside can be obtained.

Further, in this embodiment, since the heater 16 of the electromagnetic induction heating system is used as the refrigerant heating device, the refrigerant can be quickly and strongly heated, and the refrigerant can be more efficiently heated.

-Modification of Embodiment- In the above embodiment, the vertical pipe through which the refrigerant flows upward from below.
(20) is provided with heating sections (16a, 16b) to constitute a refrigerant heating device (16). The refrigerant heating device (16) of the present invention, as shown in FIG. May be provided in the vertical pipe (20) flowing through the pipe.

In this case, since the gaseous gaseous refrigerant (G) tends to rise against the flow direction of the refrigerant, a turbulent flow occurs in the refrigerant pipe (20) as shown by an arrow in FIG. Will be. Therefore, the liquid refrigerant (L) does not come into contact with a part of the refrigerant pipe (20) in a biased manner, but uniformly contacts the entire inner surface of the refrigerant pipe (20). For this reason, even in this case, a higher heat transfer coefficient can be obtained than in the conventional apparatus in which the heating section is provided in the horizontal pipe, and the heating efficiency is improved.

[0041]

Other Embodiments of the Invention The present invention may be configured as follows with respect to the above embodiment.

For example, in the above embodiment, the heater (16) is disposed between the expansion valve (12) and the outdoor heat exchanger (11), and the defrost of the outdoor heat exchanger (11) performed during the heating operation is performed. At this time, the refrigerant is heated, but the refrigerant heating device (1
The use of 6) is not limited to defrost operation.

In the above embodiment, the electromagnetic induction heating type heater (16) is described as the refrigerant heating device. However, other types of heaters such as a resistance heating type heater may be used.

[Brief description of the drawings]

FIG. 1 is a schematic circuit configuration diagram of a refrigeration apparatus using a refrigerant heating device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the refrigerant heating device of FIG.

3 is an explanatory diagram schematically showing a phase state of a refrigerant flowing in a refrigerant pipe in the refrigerant heating device of FIG.

FIG. 4 is an explanatory diagram showing a modification of FIG. 3;

FIG. 5 is an explanatory diagram schematically showing a phase state of a refrigerant flowing in a refrigerant pipe in a conventional refrigerant heating device.

[Explanation of symbols]

 (1) Air conditioner (refrigerator) (1a) Outdoor unit (1b) Indoor unit (10) Compressor (11) Outdoor heat exchanger (12) Expansion valve (13) Indoor heat exchanger (14) Outdoor blower ( 15) Indoor blower (16) Heater (refrigerant heating device) (16a) Heating part (heating part) (16b) Coil (heating part) (16c) Insulation material (16d) High frequency power supply (high frequency current generating means) (17) Frost sensor (18) Controller (20) Refrigerant piping (21) Refrigerant circuit (22) Four-way switching valve

Claims (4)

[Claims] 1. A refrigerant heating device for heating a refrigerant flowing through a refrigerant pipe (20), wherein the heating section (20) heats the refrigerant pipe (20) so as to transfer heat from the refrigerant pipe (20) to the refrigerant. 16a, 16b), and the heating section (1
6a, 16b) are refrigerant heating devices provided in refrigerant pipes (20) arranged in the vertical direction. 2. The refrigerant heating apparatus according to claim 1, wherein the heating section is provided in a refrigerant pipe through which the refrigerant flows upward from below. 3. The refrigerant heating device according to claim 1, wherein the heating section is provided in a refrigerant pipe through which the refrigerant flows from above to below. 4. The heating section (16a, 16b) includes a heating section (16) formed by using at least a part of the refrigerant pipe (20) in the longitudinal direction as a magnetic material.
a) and a coil (16b) wound around the heat generating portion (16a).
Further, a high-frequency current is supplied to the coil (16b) to generate a heating portion.
3. A high-frequency current generating means (16c) connected to the coil (16b) so as to flow an eddy current through the coil (16a).
Or the refrigerant heating device according to 3.