JP2000320909A - Refrigerating cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform heat exchange in internal heat exchange by a simple structure. SOLUTION: The refrigerating cycle includes at least a compressor 1, a condenser 2, an expansion valve 6, and an evaporator 7 and performs heat exchange of a refrigerant between an upper stream side of the expansion valve 6 and a lower stream side of the evaporator 7, wherein a heat pipe 4 of which one end comes into contact with piping 5 of the upper stream side of the expansion valve 6 and the other end comes into contact with piping 8 of the lower stream side of the evaporator 7 is provided and heat exchange is performed by the heat pipe 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration for exchanging heat between an upstream side of an expansion valve and a downstream side of an evaporator.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10, a refrigeration cycle including a compressor 1, a condenser 2, a liquid tank 3, an expansion valve 6, and an evaporator 7 provided with an internal heat exchanger 40 is known. . Note that 5 in FIG.
Is a pipe on the upstream side of the expansion valve 6 (high pressure line), and 8 is a pipe on the downstream side of the evaporator 7 (low pressure line).
When the compressor 1 is turned on, the refrigerant in the refrigeration cycle circulates from the compressor 1 through the circuit in the order of the condenser 2, the liquid tank 3, the internal heat exchanger 40, the expansion valve 6, the evaporator 7, the internal heat exchanger 40, and the compressor 1. I do. The operation in this process will be described with reference to the Mollier diagram W (a → b → c → d → e → a) of FIG.

[0003] In FIG. 11, in the Mollier diagram W, a high-temperature and high-pressure gaseous refrigerant (a →
b) is condensed and liquefied in the condenser 2 (b → c) and flows into the liquid tank 3. This refrigerant is supplied to the internal heat exchanger 4
0, and is supercooled by the cooler refrigerant passing through the evaporator 7 (c → d). The supercooled liquid refrigerant reaches the expansion valve 6 and is adiabatically expanded by the expansion valve 6 to become a low-temperature and low-pressure liquid refrigerant. Then, the liquid refrigerant is guided to the evaporator 7 and exchanges heat with the intake air. . The refrigerant that is guided to the evaporator 7 through the expansion valve 6 is sufficiently cooled in the internal heat exchanger 40, becomes a refrigerant with a small dryness, and is introduced into the evaporator 7. Thus, the conventional Mollier diagram Y (a ′ → b ′ → c → e ′ →
The cooling capacity of the evaporator 7 is improved as compared with the refrigeration cycle operated in a ′). The low-temperature, low-pressure liquid refrigerant passes through the evaporator 7 and receives heat, becomes a gaseous refrigerant at a low temperature, is guided to the internal heat exchanger 40, and cools the refrigerant from the liquid tank 3 as described above. Is returned to the compressor 1 (e → a).

That is, in the conventional refrigeration cycle, FIG.
Mollier diagram of Y of 1 (a ′ → b ′ → c → e ′ → a ′)
On the other hand, in this refrigeration cycle, the operation based on the Mollier diagram of W (a → b → c → d → e → a) is performed, so that the cooling capacity can be improved.

[0005] The internal heat exchanger 40 has a core case, a plurality of cores are laminated inside the core case, and the inside of the core communicates with the inlet and outlet of the gas refrigerant. , The space between the outside of the core and the core case is communicated with the inlet and outlet of the liquid refrigerant.

[0006]

According to this, however, heat exchange can be performed without mixing the liquid refrigerant from the liquid tank 3 and the gas refrigerant from the evaporator 7.
Since the internal heat exchanger 40 has a complicated structure in which a large number of cores are stacked, there is a disadvantage that the cost of the product itself is increased. Therefore, the present invention enables heat exchange with a simple configuration to reduce cost, and also allows retrofitting, simplifies installation, and reduces pressure loss during internal heat exchange, thereby achieving a refrigeration cycle. It is intended to further improve the efficiency.

[0007]

According to the first aspect of the present invention, there is provided a heat pipe having one end in contact with the pipe on the upstream side of the expansion valve and the other end in contact with the pipe on the downstream side of the evaporator. The heat pipe was used for heat exchange.

According to the second aspect of the present invention, the condensing part and the evaporating part of the heat pipe are in contact with each other along the refrigerant pipe.

According to the third aspect of the present invention, a tank for temporarily storing the refrigerant is provided in a part of the refrigerant pipe, and the condenser and the evaporator of the heat pipe are connected to the tank.

According to the invention of claim 4, the condensing part and the evaporating part of the heat pipe are partially inserted into the refrigerant pipe.

According to the invention of claim 5, a plurality of heat pipes are provided.

According to the invention of claim 6, the condensing section of the heat pipe is directed upward from the evaporating section.

According to the seventh aspect of the present invention, the heat transfer amount of the heat pipe is controlled according to the degree of superheating of the refrigerant or the discharge temperature of the compressor.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing an embodiment of a vehicle air conditioner according to the present invention,
The same parts as those in FIG. 10 are denoted by the same reference numerals. in this case,
A pipe (high-pressure line) 5 upstream of the expansion valve 6, that is, between the liquid tank 3 and the expansion valve 6, and a pipe (low-pressure line) 8 downstream of the evaporator 7, that is, between the evaporator 7 and the compressor 1 And the connection portions 5a and 8a of the heat pipe 4 arranged in parallel with each other. The heat pipe 4 is provided between the connecting part 5a and the connecting part 8a which are parallel to each other. As shown in FIG. 2, the heat pipe 4 has an evaporating portion 4 a at one end in contact with a side surface of a connecting portion 5 a of the pipe 5, and a condensing portion 4 b at the other end connecting to a connecting portion 8 a of the pipe 8.
The heat pipe 4 and the connecting portions 5a and 8a are integrally molded with the heat insulating material 4c and integrated with each other in such a state.

The heat pipe 4 is a pipe in which the inside of an outer cylinder made of a metal pipe having a capillary structure on the inner wall of the pipe is evacuated, and a small amount of water or CFC substitute is sealed as a working fluid.
When the evaporating section 4a of the outer cylinder is heated, the working fluid evaporates (absorption of heat due to latent heat of evaporation), and moves as a vapor stream to the low-temperature condensing section 4b at high speed. The working fluid then contacts the pipe wall, is cooled and condenses (releases heat due to latent heat of condensation), and the condensate returns to the heating section by capillary action or gravity and evaporates again.
Heat is continuously transported by repeating the transfer → condensation cycle. As a result, the connecting portion 5a of the pipe 5 and the pipe 8
Can be exchanged with the connecting portion 8a, and the refrigerant in the pipe 5 can be cooled.

According to such a configuration, the refrigeration cycle operates based on the Mollier diagram X (aa → bb → c → d → e → aa) showing the operation of the refrigeration cycle having the heat pipe of FIG. That is, the compressor 1 compresses the low-temperature and low-pressure gaseous refrigerant heat-exchanged by the evaporator 7 using the engine or the like as a driving source, and converts the low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gaseous refrigerant. In the Mollier diagram X of FIG. 11, it corresponds to aa → bb. The condenser 2 condenses the gaseous refrigerant at a high temperature and pressure by the compressor 1 by heat exchange with the outside air. The liquid tank 3 extracts a liquid refrigerant from the medium-temperature and high-pressure refrigerant in a gas-liquid mixed state in the condenser 2, and the liquid refrigerant extracted through the liquid tank 3 is directly used as an expansion valve 6. Where it is adiabatically expanded to become a low-temperature low-pressure refrigerant. In the first embodiment, based on the heat exchange action of the heat pipe 4, before the adiabatic expansion is performed by the expansion valve 6, the medium-temperature and high-pressure liquid refrigerant is sufficiently supercooled and then adiabatically expanded. That is, the refrigerant in the pipe 5 between the liquid tank 3 and the expansion valve 6 is cooled by the refrigerant in the pipe 8 between the evaporator 7 and the compressor 1 using the heat pipe 4.

In the first embodiment, due to the heat exchange effect of the heat pipe 4, the Mollier diagram X shown in FIG.
An operation based on (aa → bb → c → d → e → aa) is performed, and an improvement in cooling capacity substantially equivalent to an operation based on the Mollier diagram W having the internal heat exchanger 40 can be achieved. Moreover, since the refrigerant does not flow through a complicated path in the internal heat exchanger 40, the power can be reduced and the heat exchange efficiency can be improved.

Embodiment 2 FIG. As shown in FIG. 3, the heat pipe 4 is formed by bending the evaporating section 4a and the condensing section 4b at both ends in the same direction at right angles to the main body of the heat pipe 4 to form a U-shape as a whole. And the condensing part 4b,
The connecting portion 5a of the pipe 5 and the connecting portion 8a of the pipe 8 may be contacted and connected along the connecting portion 8a. According to this, the heat transfer effect between the evaporating section 4a and the connecting section 5a and between the condensing section 4b and the connecting section 8a can be further enhanced, and the heat pipe 4
Can improve heat exchange efficiency.

Embodiment 3 Also, as shown in FIG.
Even if the tanks 4d and 4e capable of temporarily storing the refrigerant passing through the connection portion 8a of the pipe 8 and the connection portion 5a of the pipe 5 are provided, and both ends of the heat pipe 4 are fitted and connected to the tanks 4d and 4e. good. Thereby, the heat pipe 4 and the connection portion 5
a, 8a can be improved in heat transfer efficiency.

Embodiment 4 Also, as shown in FIG.
The heat pipe 4 may be attached such that both ends thereof are fitted into the connection 8a of the pipe 8 and the connection 5a of the pipe 5. According to this, since the refrigerant directly contacts the evaporating section 4a and the condensing section 4b at both ends of the heat pipe, the heat transfer efficiency can be increased.

Embodiment 5 Also, as shown in FIG.
Between the connecting portion 8a of the pipe 8 and the connecting portion 5a of the pipe 5,
The two heat pipes 4m and 4n are connected so as to sandwich the connecting portion 8a and the connecting portion 5a from both sides.
A part of m and 4n may be integrated with the heat insulating material 4c. Thereby, the heat exchange efficiency can be further improved.

Embodiment 6 FIG. In Embodiments 2 to 5 shown in FIGS. 3 to 6, regarding the heat pipe 4, the condenser 4 b is positioned above the evaporator 4 a,
It was arranged vertically. According to this, since the working fluid condensed in the condenser 4b of the heat pipe 4 falls by gravity and easily flows downward, the heat pipe 4 is positioned by placing the condenser 4b on the upper side. Since the circulating capacity of the working fluid in the inside can be improved, the heat exchange efficiency of the heat pipe can be improved.

Embodiment 7 Further, in the present invention, as shown in FIG. 7, the heat pipe 4 is adjusted so that the heat exchange efficiency can be adjusted by adjusting the refrigerant amount adjusting valve portion 4h provided inside by the input signal to the electromagnetic portion 4g. The controller 4t is provided with a controller 4t, and the controller 4t can control the electromagnetic unit 4g based on the degree of superheat calculated from the temperature and pressure detected by the temperature sensor 4i and the pressure sensor 4j. May be. The operation of the refrigeration cycle in such a configuration will be described below with reference to the flowchart shown in FIG. First, in step S1, the flow is started, and in step S2, the controller 4t operates the temperature sensor 4i.
And the signal of the pressure sensor 4j, and calculates the superheat degree in step S3 to determine whether or not the superheat degree is a predetermined value. If not, the superheat degree and the predetermined value are determined in step S5. As a result of this comparison, if the degree of superheat is smaller than a predetermined value, an open signal (large heat exchange by the heat pump 4) is sent. If the degree of superheat is larger than the predetermined value, a close signal (low heat exchange by the heat pump 4) ) To control the heat exchange of the heat pipe 4. With the above open signal, the amount of heat exchange by the heat pump 4 can be increased to increase the degree of superheat,
Since the heat exchange amount can be reduced by the close signal, the degree of superheat can be reduced. Therefore, the degree of superheat can be automatically adjusted.

Embodiment 8 FIG. In addition, as shown in FIG.
Providing a sensor 4y for detecting the discharge temperature of the compressor, controlling the electromagnetic portion 4g of the heat pipe 4 based on the discharge temperature of the compressor detected by the sensor 4y, and controlling the heat transfer amount of the heat pipe 4. Then, the heat exchange amount may be adjusted.

[0025]

According to the first aspect of the present invention, there is provided a heat pipe having one end in contact with the pipe on the upstream side of the expansion valve and the other end in contact with the pipe on the downstream side of the evaporator. Since the above-described heat exchange is performed, the structure of the heat exchange portion is simplified, cost can be reduced, and since the heat pipe can be mounted, retrofitting is possible, mounting is easy, and performance can be improved.

According to the second aspect of the present invention, since the condensing portion and the evaporating portion of the heat pipe are in contact with each other along the refrigerant pipe, the heat transfer efficiency between the heat pipe and the refrigerant pipe can be improved.

According to the third aspect of the invention, a tank for temporarily storing the refrigerant is provided in a part of the refrigerant pipe, and the condensing part and the evaporating part of the heat pipe are connected to this tank. Heat can be reliably transferred inside.

According to the fourth aspect of the present invention, since the condensing part and the evaporating part of the heat pipe are partially inserted into the refrigerant pipe,
Heat inside the refrigerant pipe can be reliably transferred to the heat pipe.

According to the fifth aspect of the present invention, since a plurality of heat pipes are provided, the heat exchange rate by the heat pipes can be increased.

According to the sixth aspect of the present invention, since the condensing portion of the heat pipe is made higher than the evaporating portion, the circulation efficiency of the working fluid in the heat pipe can be improved.

According to the seventh aspect of the present invention, the heat transfer amount of the heat pipe is controlled in accordance with the degree of superheat of the refrigerant or the discharge temperature of the compressor, so that the degree of superheat and the discharge temperature of the compressor can be automatically adjusted. Become.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is a side view showing another embodiment of the present invention.

FIG. 4 is a side view showing another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing another embodiment of the present invention.

FIG. 7 is a block diagram showing another embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation of another embodiment of the present invention.

FIG. 9 is a block diagram showing another embodiment of the present invention.

FIG. 10 is a block diagram showing an example of a conventional example.

FIG. 11 is a characteristic diagram showing an operation example of the present invention and a conventional example.

[Explanation of symbols]

1 compressor, 2 condensers, 3 liquid tanks, 4 heat pipes, 5 pipes (high pressure line), 5a
Connection, 6 expansion valve, 7 evaporator, 8 piping (low pressure line), 8a connection, 40 internal heat exchanger.

Claims (7)

[Claims] In a refrigeration cycle having at least a compressor, a condenser, an expansion valve, and an evaporator, and performing heat exchange of refrigerant between an upstream side of the expansion valve and a downstream side of the evaporator, one end is located upstream of the expansion valve. A refrigeration cycle, wherein a heat pipe is provided, the heat pipe being in contact with the pipe and the other end being in contact with the pipe on the downstream side of the evaporator, and the heat pipe is used for the heat exchange. 2. The refrigeration cycle according to claim 1, wherein the condensing section and the evaporating section of the heat pipe are in contact with each other along the refrigerant pipe. 3. The refrigeration cycle according to claim 1, wherein a tank for temporarily storing the refrigerant is provided in a part of the refrigerant pipe, and a condenser and an evaporator of the heat pipe are connected to the tank. 4. The refrigeration cycle according to claim 1, wherein the condensing part and the evaporating part of the heat pipe are partially inserted into the refrigerant pipe. 5. The heat pipe according to claim 1, wherein a plurality of heat pipes are provided.
The refrigeration cycle according to 1. 6. The refrigeration cycle according to claim 1, wherein the condensing section of the heat pipe faces upward from the evaporating section. 7. The refrigeration cycle according to claim 1, wherein the heat transfer amount of the heat pipe is controlled according to the degree of superheat of the refrigerant or the discharge temperature of the compressor.