JP2004028525A - Accumulator and refrigeration cycle using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an accumulator increased in refrigeration effect and improved in cooling performance, to provide a refrigeration cycle using the accumulator, to improve gas-liquid separation to miniaturize the accumulator, and to prevent fear of liquid compression by a compressor. <P>SOLUTION: This refrigeration cycle 1 has: the compressor 2 increasing pressure of a refrigerant; a condenser 3 condensing the refrigerant; a capillary tube 4 decompressing the refrigerant cooled by the condenser 3; an evaporator 5 evaporating the low-pressure refrigerant decompressed by the capillary tube 4; and the accumulator 6 allowing inflow of the refrigerant passing through the evaporator 5. The accumulator 6 has: a vessel 8 formed with a storage space 7 storing the refrigerant; an inflow port 9 allowing the inflow of the refrigerant into the storage space 7; and an outflow port 11 communicating with a gas phase area of the storage space 7, allowing outflow of the refrigerant from the gas phase area. The capillary tube 4 is disposed in the gas phase area. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an accumulator used for accumulating a refrigerant, and a refrigeration cycle using the accumulator.
[0002]
[Prior art]
As a refrigeration cycle, as shown in FIG. 7, a compressor 2 for increasing the pressure of a refrigerant, a condenser 3 for condensing the refrigerant, a capillary tube 4 for decompressing the refrigerant cooled by the condenser 3, and this capillary tube An accumulator cycle including an evaporator 5 for evaporating and evaporating the refrigerant decompressed in 4 and an accumulator 6 for flowing the refrigerant passing through the evaporator 5 are used in some car air conditioners and the like. . Such an accumulator cycle is such that an accumulator is provided on the outlet side of the evaporator 5 instead of the receiver, and the capillary tube 4 having a fixed valve opening is used instead of the thermal expansion valve. Since the gas-liquid is separated and the liquid refrigerant is stored, the gas phase region to which the outlet in the accumulator communicates is in a state filled with saturated gas, and the outlet of the accumulator is on the Mollier diagram. It is on the saturation gas line, and in theory only saturated gas is sent to the compressor.
[0003]
[Problems to be solved by the invention]
However, in such an accumulator cycle, since the refrigerant that has passed through the capillary tube contains a large amount of gas that does not contribute to cooling, there is a disadvantage that efficient heat exchange cannot be performed. Further, if an attempt is made to reduce the size of the accumulator, it is not possible to secure a sufficient volume in the accumulator to perform gas-liquid separation, and the liquid refrigerant may return to the compressor and cause liquid compression.
[0004]
Therefore, it is a main object of the present invention to provide an accumulator capable of increasing a refrigeration effect and improving cooling performance, and a refrigeration cycle using the accumulator. Another object is to improve the gas-liquid separation to reduce the size of the accumulator, and to prevent the possibility of liquid compression by the compressor.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an accumulator according to the present invention communicates with a container in which a storage space for storing a refrigerant is formed, an inflow port through which the refrigerant flows into the storage space, and a gas phase region of the storage space. And an outlet through which a refrigerant flows out of the gas phase region, and a capillary tube is disposed in the gas phase region (claim 1).
[0006]
Here, as a method of disposing the capillary tube in the gas phase region, a part of the capillary tube may be disposed in the gas phase region, or the entire capillary tube may be disposed in the gas phase region. It may be.
[0007]
Therefore, since the capillary tube used in the refrigeration cycle is disposed in the gas phase region of the accumulator, the refrigerant passing through the capillary tube is cooled by the saturated gas in the storage space in the process of being depressurized, thereby increasing the refrigeration effect. Can be achieved. Further, since the refrigerant guided to the outlet of the accumulator is heated by the refrigerant passing through the capillary tube, the liquid refrigerant mixed in the gas phase region can be completely vaporized.
[0008]
Here, in order to increase the heat exchange efficiency between the refrigerant in the capillary tube and the gas-phase refrigerant in the accommodation space, the flow of the refrigerant flowing through the capillary tube and the flow of the refrigerant from the inlet to the outlet may be made to flow in opposite directions. (Claim 2) Preferably, the capillary tube is provided with fins (Claim 3).
[0009]
The accumulator described above is formed in a container or a member separate from the container, and communicates with a sub-storage space connected to the outlet side of the capillary tube and a liquid phase region of the sub-storage space. And a communication path connecting the gas phase region of the sub-storage space to the gas phase region of the storage space may be further provided.
[0010]
In such a configuration, the refrigerant that has passed through the capillary tube is gas-liquid separated in the sub-accommodation space, and only the liquid-phase refrigerant flows out of the outlet, so that the enthalpy of the refrigerant that has flowed out is reduced to above the saturated liquid line. And the refrigeration effect can be increased. Also in this configuration, since the refrigerant gas guided to the outlet of the accumulator is heated by the refrigerant passing through the capillary tube, the mixed liquid refrigerant can be completely vaporized.
[0011]
In the case of constructing a refrigeration cycle including the above-described accumulator, that is, a compressor for increasing the pressure of the refrigerant, a condenser for condensing the refrigerant, a capillary tube for reducing the pressure of the refrigerant cooled by the condenser, and the capillary tube When constructing a refrigeration cycle having an evaporator that evaporates the depressurized refrigerant and an accumulator that flows the refrigerant that has passed through the evaporator, the accumulator is a container having an accommodation space for accommodating the refrigerant. And an inlet for flowing the refrigerant that has passed through the evaporator into the housing space, and an outlet communicating with the gas phase region of the housing space and allowing the refrigerant to flow out of the gas phase region to the compressor. Preferably, a capillary tube is provided (claim 5).
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a refrigeration cycle 1 includes a compressor 2 for compressing a refrigerant, a condenser 3 for condensing the refrigerant, a capillary tube 4 for decompressing the refrigerant flowing out of the condenser 3, and an evaporator 5 for evaporating and evaporating the refrigerant. And an accumulator 6 for gas-liquid separation of the refrigerant flowing out of the evaporator 5.
[0013]
Here, the accumulator 6 is configured to house the capillary tube 4. As shown in FIG. 2, the accumulator 6 includes a container 8 in which a housing space 7 for housing a refrigerant is formed, and a storage space 7. Inlet 9 formed on the side of the container so that the refrigerant flows into the container, and an outlet pipe 10 which opens into the gas phase region of the storage space 7 and extends downward from this gas phase region to pass through the liquid phase region. And an outlet 11 formed below the container 8 via the outlet pipe 10.
[0014]
The capillary tube 4 is disposed in the gas phase region of the housing space 7 so as to surround the vicinity of the upper end of the outlet tube 10, and is entirely housed in the housing space 7, and has one end formed on the side wall of the container. The other end is connected to a tube outlet 13 formed on the side wall of the container. The capillary tube 4 is disposed such that the flow of the refrigerant flowing therethrough and the flow of the refrigerant flowing from the inlet to the outlet in the storage space 7 are in counter flow, and the temperature gradient in the capillary tube 4 is The temperature gradient in the space 7 is made to match. That is, since the gas-phase refrigerant in the storage space 7 moves upward from below and enters the outlet pipe 10, the capillary tube 4 is formed such that the refrigerant inside moves spirally from above to below. .
[0015]
A baffle plate 15 having a through hole 14 is provided horizontally below the capillary tube 4 in the accommodation space 7, and the inside of the accommodation space 7 accommodates the capillary tube 4, and an upper end opening of the outlet tube 10 is provided. The space is divided into a tube housing space 7 a communicating with the section and a separation chamber 7 b communicating with the inflow port 9 for separating the inflow refrigerant into gas and liquid. The through-hole 14 is provided at a position facing the capillary tube 4 so that the gas-phase refrigerant flowing upward from the through-hole 14 hits the capillary tube 4. Reference numeral 23 in the drawing denotes an oil return hole for collecting oil mixed in the liquid refrigerant.
[0016]
In the refrigeration cycle 1 including the above-described accumulator 6, the discharge port (D) of the compressor 2 is connected to the inlet of the condenser 3, and the outlet of the condenser 3 is connected to the tube inlet 12 of the accumulator 6. The tube outlet 13 of the accumulator 6 is connected to the inlet of the evaporator 5. The outlet of the evaporator 5 is connected to the inlet 9 of the accumulator 6, and the outlet 11 of the accumulator 6 is connected to the inlet (S) of the compressor 2.
[0017]
Therefore, a high-pressure line 16 is formed from the discharge port (D) of the compressor 2 to the capillary tube 4 accommodated in the accumulator 6, and a low-pressure line 17 is formed from the capillary tube 4 to the suction port (S) of the compressor 2. Have been.
[0018]
In the refrigeration cycle 1, R134a is used as a refrigerant. The refrigerant compressed by the compressor 2 is condensed by the condenser 3 and then enters the capillary tube 4 housed in the accumulator 6, where it is decompressed. At the same time, it is cooled by exchanging heat with the gas phase refrigerant in the housing space 7 (tube housing space 7a). Then, the refrigerant that has passed through the evaporator 5 enters the separation chamber 7b of the accumulator 6 through the inflow port 9, where it is separated into gas and liquid. Led to. The refrigerant guided to the outlet pipe 10 is heated by exchanging heat with the refrigerant in the capillary tube 4 arranged in the tube accommodating space 7a, is heated, and is returned from the outlet 11 to the compressor 2 through the outlet pipe 10.
[0019]
The operation of the above-described refrigeration cycle will be described with reference to a Mollier diagram shown in FIG. 3 while comparing with the conventional refrigeration cycle. The conventional refrigeration cycle shown in FIG. 7 in which the accumulator 6 and the capillary tube 4 are separately arranged is shown. , The refrigerant repeats the state change of a1 → b1 → c → d1 → a1, as shown by the broken line in FIG. That is, the refrigerant is compressed from the state of a1 to an appropriate pressure by the compressor 2 to become b1, and then condensed and cooled by the condenser 3 to be in a supercooled state c. After that, the pressure becomes lower in the capillary tube 4 to be in the state d1, and after absorbing heat in the evaporator 5, it enters the separation chamber 7b of the accumulator 6, where it is separated into gas and liquid to become a saturated gas in the state a1, Returned to inlet. Therefore, the coefficient of performance (COP) of the refrigeration cycle 1 is A / B.
[0020]
On the other hand, in the refrigeration cycle 1 shown in FIG. 1 in which the capillary tube 4 is accommodated in the accumulator 6, the refrigerant repeatedly changes the state as a2 → b2 → c → d2 → a2 as shown by the solid line in FIG. . That is, since the capillary tube 4 is provided in the gas phase region of the storage space 7 of the accumulator 6 (in this example, the tube storage space 7a), the high-pressure refrigerant flowing into the capillary tube 4 is depressurized here. Is cooled by the low-temperature refrigerant gas filled in the gas phase region of the accumulator 6, and the enthalpy at the outlet of the capillary tube 4 becomes d2 smaller than d1 (d2 <d1). The refrigerant contained in the storage space 7 of the accumulator 6 is heated by the refrigerant passing through the capillary tube 4 in the process of being guided to the outlet pipe 10, so that the enthalpy at the outlet 11 of the accumulator 6 changes from a1 to a2. Will increase.
[0021]
Therefore, in the refrigeration cycle 1, the work amount of the compressor 2 is almost the same as the conventional one (B = B '). A increases from A to A ′, and the cooling capacity of the evaporator 5 can be increased. Further, since the refrigerant flowing out of the evaporator 5 is heated by the capillary tube 4, the refrigerant flows into the outlet pipe 10 in a completely vaporized state, and only the gas-phase refrigerant is returned to the compressor 2, and 2 eliminates the risk of liquid compression. Moreover, even when the volume for performing the gas-liquid separation is small, the gas-liquid separation can be effectively performed by heat exchange with the refrigerant passing through the capillary tube, so that the accumulator can be reduced in size. The size of the refrigeration cycle 1 can be reduced.
[0022]
In the above configuration, the amount of increase in the cooling capacity is determined by the amount of heat exchange between the refrigerant flowing through the capillary tube 4 and the gas-phase refrigerant in the accumulator 6, so that the amount of increase in the cooling capacity is increased. For this purpose, as shown in FIG. 4, for example, plate fins 18 may be provided in the capillary tube 4 to promote heat exchange.
[0023]
As shown in FIG. 5, by partitioning the inside of the container 8 or by attaching a separate member to the outside of the container 8, the container, or a member that is separate from the container 8, A sub-accommodating space 20 for connecting the outlet side of the capillary tube 4 is formed, and the accumulator 6 is opened in the liquid phase region of the sub-accommodating space 20 and extends upward from the liquid phase region to pass through the gas phase region. Outgoing pipe 21, an outlet 13 ′ formed above the container 8 through the outlet pipe 21 and allowing the liquid-phase refrigerant to flow out to the inlet of the evaporator 5, A communication path 22 that communicates with the gas phase region of the storage space 20 may be further provided.
[0024]
Here, if the gas-liquid separation in the sub-accommodation space 20 is successfully performed, the communication passage 22 has an opening end opening to the accommodation space 7 so as to face the tube accommodation space 7a (in this example, in this example). Is opened so as to face the opening at the upper end of the outlet pipe 10). If the gas-liquid separation in the sub-accommodation space 20 is not performed properly, the gas-liquid separation needs to be performed again in the accommodation space 7. An opening is formed in the gas phase region of the chamber 7b (indicated by a dashed line in the figure). In other respects, the configuration is the same as that of the above-described configuration example.
[0025]
Therefore, in the refrigeration cycle 1 including such an accumulator 6, the refrigerant compressed by the compressor 2 is cooled and condensed in the condenser 3, and then decompressed in the capillary tube 4 housed in the accumulator 6. At the same time, the heat is exchanged with the gas-phase refrigerant in the storage space 7 (tube storage space 7 a) to be further cooled and supplied to the sub-storage space 20. After the gas-liquid separation in the sub-accommodation space 20, only the liquid-phase refrigerant is supplied to the evaporator 5 from the outlet 13 'through the outlet pipe 21. After that, the refrigerant that has passed through the evaporator 5 enters the separation chamber 7b of the accumulator 6 through the inflow port 9, where the refrigerant is separated into gas and liquid, and the separated gas-phase refrigerant is guided to the outlet pipe 10, It is heated by the refrigerant passing through the capillary tube 4 and then returned from the outlet 11 to the compressor 2 through the outlet pipe 10.
[0026]
The operation of the refrigeration cycle 1 including the accumulator 6 described above will be described with reference to the Mollier diagram in FIG. 6. As shown by the solid line, the refrigerant has the following order: a2 → b2 → c → d2 → d3 → a1 → a3 → a2 Repeat the state change. That is, since the capillary tube 4 is provided in the gas phase region of the storage space 7 of the accumulator 6, the high-pressure refrigerant flowing into the capillary tube 4 is depressurized by the capillary tube 4, and Cooled by the filled saturated gas, the enthalpy at the outlet of the capillary tube 4 decreases from d1 to d2. Further, since the gas and liquid are separated in the sub-accommodating space 20, and only the liquid-phase refrigerant flows out, the refrigerant flowing out from the outlet 13 'is a saturated liquid, and the enthalpy decreases from d2 to d3. Then, this refrigerant enters the evaporator 5 in the state of d3, absorbs heat, is separated into gas and liquid by the accumulator 6, becomes a1, and is then heated by the refrigerant passing through the capillary tube 4 to become a3. Thereafter, the refrigerant mixes with the low-temperature gas-phase refrigerant flowing out of the sub-accommodating space 20 and flows out. Therefore, the state is set to a 2 at the outlet 11 of the accumulator 6 and returned to the compressor 2.
[0027]
Therefore, in such a refrigeration cycle 1, the work of the compressor 2 is almost the same (B = B ′) as compared with the conventional refrigeration cycle indicated by a broken line, but the capillary tube 4 has the gas of the accumulator 6. The refrigeration effect is increased from A to A 'by the amount of cooling by the phase refrigerant and the amount of the saturated liquid in the sub-accommodation space 20, and the cooling capacity of the evaporator 5 can be increased. Further, since the refrigerant flowing out of the evaporator 5 is heated by the capillary tube 4, it is possible to return the refrigerant to the compressor 2 in a completely gaseous state. It is possible to eliminate fear. Furthermore, even when the volume for performing gas-liquid separation is small, gas-liquid separation can be performed effectively, so that the accumulator 6 can be reduced in size and, consequently, the refrigeration cycle 1 can be reduced in size. .
[0028]
In the above-described configuration, the configuration has been described in which the entire capillary tube 4 is stored in the gas phase region of the storage space 7 of the accumulator 6, but a part of the capillary tube 4 is stored in the gas phase region of the storage space 7. It may be.
[0029]
【The invention's effect】
As described above, according to the present invention, the container in which the accommodation space for accommodating the refrigerant is formed, the inflow port through which the refrigerant flows into the accommodation space, and the vapor space in the accommodation space are communicated with each other. In the accumulator having an outlet for allowing the refrigerant to flow out from the accumulator, since the capillary tube is disposed in the gas phase region of the storage space, the refrigerant passing through the capillary tube can be cooled by the saturated gas in the storage space, Cooling performance can be improved.
[0030]
Further, since the refrigerant guided to the outlet of the accumulator is heated by the refrigerant passing through the capillary tube, the liquid refrigerant mixed in the gas phase region can be completely vaporized, and the performance of gas-liquid separation is improved. It is possible to reduce the size of the accumulator and, consequently, the size of the refrigeration cycle, and to prevent the possibility of liquid compression by the compressor.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a refrigeration cycle according to the present invention.
FIG. 2 is a diagram showing a configuration example of an accumulator used in a refrigeration cycle according to the present invention.
FIG. 3 is a Mollier diagram showing an operation of a refrigeration cycle when the accumulator shown in FIG. 2 is used.
FIG. 4 is a diagram showing another configuration example of the accumulator used in the refrigeration cycle according to the present invention.
FIG. 5 is a diagram showing still another configuration example of the accumulator used in the refrigeration cycle according to the present invention.
FIG. 6 is a Mollier diagram showing an operation of a refrigeration cycle when the accumulator shown in FIG. 5 is used.
FIG. 7 is a diagram showing a conventional accumulator cycle.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Compressor 3 Evaporator 4 Capillary tube 5 Evaporator 6 Accumulator 7 Storage space 8 Container 9 Inflow port 11 Outflow port 18 Plate fin 20 Sub storage space 23 Oil return hole

Claims (5)

A container in which a storage space for storing the refrigerant is formed, an inlet for flowing the refrigerant into the storage space, and an outlet communicating with a gas phase region of the storage space and allowing the refrigerant to flow out of the gas phase region. An accumulator, wherein a capillary tube is provided in the gas phase region. 2. The accumulator according to claim 1, wherein the flow of the refrigerant flowing through the capillary tube and the flow of the refrigerant from the inflow port to the outflow port are opposed to each other. The accumulator according to claim 1, wherein a fin is provided on the capillary tube. The container, or a member formed separately from the container, communicates with a sub-housing space connected to the outlet side of the capillary tube, and a liquid phase region of the sub-housing space, and the refrigerant flows out of the liquid phase region. The accumulator according to claim 1, further comprising an outlet to be connected and a communication path connecting the gas phase region of the sub-storage space to the gas phase region of the storage space. A compressor that pressurizes the refrigerant,
A condenser for condensing the refrigerant,
A capillary tube for reducing the pressure of the refrigerant cooled by the condenser,
An evaporator for evaporating the refrigerant depressurized by the capillary tube;
Comprising an accumulator that flows the refrigerant that has passed through the evaporator,
The accumulator communicates with a container in which a storage space for storing the refrigerant is formed, an inflow port through which the refrigerant having passed through the evaporator flows into the storage space, and a gas phase region of the storage space. And an outlet for allowing a refrigerant to flow out of the compressor to the compressor, and the capillary tube is disposed in the gas phase region.

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