JPH11281207A - Vapor compression chiller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering of compression efficiency or damage of a compressor through a simple arrangement without causing increase in the overall size or complication. SOLUTION: An accumulator 8 comprises a container body 11, a pipe 12 for introducing refrigerant from an evaporator into the container body 11, a pipe 13 for supplying gas refrigerant separated from liquid in the container body 11 to a compressor 2, and a hole 14 for returning lubricant contained in the liquid separated from gas in the container body 11 to the compressor 2. The container body 11 is divided into a plurality of sections and the oil return hole 14 is located in the liquid within one section thus divided in order to heat the liquid utilizing heat generated from the compressor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor compression refrigeration system for cooling and heating operations, hot water supply / freezing, and the like.
The present invention relates to an improvement in an accumulator that effectively utilizes heat energy generated from a compressor.

[0002]

2. Description of the Related Art Conventionally, a refrigerant circuit of a vapor compression refrigeration system used for indoor air conditioning is configured as shown in FIG. Hereinafter, the refrigeration cycle of the refrigerant circuit will be described.

[0003] During cooling, the refrigerant discharged from the compressor 2 flows as indicated by the solid line arrow by setting the four-way valve 1 to the solid line state. On the other hand, at the time of heating, by setting the four-way valve 1 to the broken line state, the refrigerant discharged from the compressor 2 flows as indicated by the broken line arrow.

[0004] Here, 3 is an indoor heat exchanger that acts as an evaporator during cooling and acts as a condenser during heating, 4 is an indoor fan for sending air to the indoor heat exchanger 3, and 5 is a condenser during cooling. An outdoor heat exchanger that functions as an evaporator during heating, 6 is an outdoor fan that sends air to the outdoor heat exchanger 5, 7 is a capillary tube, and 8 is an accumulator.

Next, with reference to a Mollier diagram shown in FIG. 3, a change in refrigerant state in the refrigeration cycle will be described. In FIG. 3, the vertical axis represents pressure and the horizontal axis represents enthalpy. In the drawing, x is a curve indicating a boundary between a gas phase state, a liquid phase state, and a gas-liquid two-phase state of the refrigerant, a curve portion on the right side from the vertex y indicates a saturated vapor line, and a curve on the left side from the vertex y. The part shows the saturated liquid line.

The refrigerant is superheated steam in the region on the right side of the saturated vapor line, and the refrigerant is wet vapor in the region on the left side of the saturated vapor line. Further, the refrigerant is in a liquid state in a region on the left side of the saturated liquid line, and is in a wet vapor state in a region on the right side of the saturated liquid line. Therefore, between a and b in the figure, the refrigerant is compressed by the compressor 2 to become high-temperature and high-pressure superheated steam. Further, between bc in the figure, the refrigerant is condensed in the condenser, and changes from a superheated vapor state to a liquid state. Then, between cd in the figure, the refrigerant is decompressed by the capillary tube 7 to become a liquid refrigerant in a gas-liquid two-phase state (liquid refrigerant and vapor refrigerant). Between d and a in the figure, the liquid refrigerant evaporates by removing heat from the surroundings in the evaporator and becomes superheated steam.
Then, the refrigerant that has become the superheated steam is sent into the compressor 2 again.

However, in practice, as described above, not all of the refrigerant returned from the evaporator returns to superheated vapor, and some refrigerant may be in a liquid state. And
Conventionally, in order to prevent the liquid refrigerant from returning to the compressor 2 and damaging the compressor 2, gas-liquid separation is performed by an accumulator 8 and only the gas refrigerant is supplied to the compressor 2.

In the accumulator 8, as shown in FIG. 4, the refrigerant discharged from the evaporator is introduced into the container 42 through the inflow pipe 41, separated into gas and liquid, and the liquid refrigerant is placed in the lower part of the container 42. Further, the gas refrigerant accumulates in the upper part of the container 42 and is returned to the compressor 2 via the outflow pipe 43. Then, the lubricating oil accumulated in the container 42 together with the refrigerant liquid is also sucked into the outflow pipe 43 from the oil return hole 44 and returned to the compressor 2 through the outflow pipe 43.

[0009]

However, in the conventional apparatus, when a large amount of refrigerant liquid is returned from the evaporator, not only the lubricating oil but also the liquid refrigerant may enter the compressor 2 from the oil return hole 44. There is a possibility that the compression efficiency is reduced or the compressor is damaged.

When two or more non-azeotropic mixed refrigerants are used as the working fluid, a high-boiling refrigerant is stored as a liquid refrigerant in the container 42 of the accumulator 8, resulting in a refrigeration cycle. There is also a problem that the composition of the mixed refrigerant circulating in the inside greatly changes from the composition of the sealed refrigerant, and the system efficiency of the entire apparatus is reduced.

For this reason, conventionally, it has been proposed to separately provide a heating device or the like to vaporize the liquid refrigerant in the container 42 of the accumulator 8. However, in this conventional device, a heating device and the like must be separately provided,
There has been a problem that the whole apparatus becomes complicated and the system efficiency is reduced due to the driving of the apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vapor compression refrigeration apparatus which has a simple structure and prevents a reduction in compression efficiency and damage to a compressor without increasing the size and complexity of the entire apparatus. I do.

[0013]

According to the present invention, there is provided a vapor compression refrigeration apparatus comprising a compressor, a condenser, a decompressor, an evaporator, and an accumulator to constitute a refrigeration cycle, wherein the accumulator comprises: An inflow pipe for introducing the refrigerant from the evaporator into the container main body, an outflow pipe for supplying the gas refrigerant separated into gas and liquid in the container main body to the compressor, and an outlet pipe provided in the outflow pipe. An oil return hole for returning the lubricating oil contained in the gas-liquid separated liquid to the compressor, wherein the container main body is divided into a plurality of parts and is located in the liquid in one of the divided container main bodies. The oil return hole is provided as described above, and the liquid is heated using heat generated by the compressor.

By using this configuration, it is possible to prevent reduction in compression efficiency and damage to the compressor without separately providing a heating device or the like. Then, the one container main body may be adjacent to the periphery of the compressor, and the liquid in the one container main body may be heated using heat generated by the compressor. By using this configuration, a reduction in compression efficiency and damage to the compressor can be prevented with a simple configuration.

[0015] The container body may include a first container body,
The second container body is divided into a second container body having a smaller volume than the first container body, and the second container body is adjacent to the periphery of the compressor, and the oil return hole is provided in the second container body. It is good also as composition provided so that it might be located in liquid. By using this configuration, the inside of the second container main body having a small volume is heated by using heat generated by the compressor, so that the liquid can be quickly vaporized and mixed with the lubricating oil through the oil return hole. It is possible to reliably suppress the refrigerant from entering the compressor.

Further, a configuration using two or more kinds of non-azeotropic mixed refrigerants as the working fluid may be adopted. Thus, even when a non-azeotropic mixed refrigerant is used, the composition of the circulating refrigerant due to gas-liquid separation inside the accumulator does not significantly change from the composition of the sealed refrigerant.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vapor compression refrigeration system according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an accumulator of a vapor compression refrigeration apparatus showing one embodiment of the present invention. still,
Since the basic operation principle of the refrigeration cycle of the refrigerant circuit is the same as that of the above-described conventional example (FIG. 2), the same reference numerals are given and the description is omitted.

As shown in FIG. 1, the accumulator 8 of the present invention comprises a container body 11, an inflow pipe 12 provided on the upper part of the container body 11 for introducing a refrigerant from an evaporator into the container body 11, a container body 11 An outlet pipe 13 for supplying the gas refrigerant, which has been gas-liquid separated therein, to the compressor 2, and an oil return hole 14 provided in the outlet pipe 13 so as to be located in the liquid refrigerant in the container body 11. Have been.

The container main body 11 is the first container main body 1.
5 and a second container body 16 having a smaller volume than the first container body 15, and the first container body 15 and the second The container body 16 is in communication. Further, the second container body 16 is arranged adjacent to the periphery of the compressor 2, and is arranged such that the bottom surface of the second container body 16 is lower than the bottom surface of the first container body 15. I have.

As a result, the second container body 16 is heated using the heat generated by the compressor 2 and the container body 1 is heated.
Even if the liquid level of the gas-liquid separated liquid in the tank 1 becomes low, the liquid will remain in the second container body 16.

The outflow pipe 13 has a gas refrigerant suction port having a first port.
The oil return hole 14 is disposed so as to
Are arranged on the bottom surface of the second container body 16. Then, the lubricating oil in the liquid accumulates in the lower portion inside the second container body 16, is gradually sucked into the oil return hole 14, and is returned to the compressor 2 via the outflow pipe 13.

As described above, since the container body 11 of the accumulator 8 is divided and the second container body 16 for heating by the heat generated from the compressor 2 has a small volume, the amount of heat applied to a single volume of the liquid refrigerant is reduced. Becomes large, and the second container body 16
The liquid refrigerant inside can be efficiently vaporized, and the liquid refrigerant mixed with the lubricating oil from the oil return hole 14 can be reliably prevented from entering the compressor 2.

When a non-azeotropic refrigerant mixture is used as the working fluid, for example, when a refrigerant such as R-407C is used, the boiling point of the refrigerant mixture is -51.50 for R-32.
° C, R-125 is -48.34 ° C, R-134a is -2.
5.93 ° C ("The Japan Refrigeration Association Thermodynamic Table JAR Thermodyna
mic Tables Volume 1 HFCs and HCFCs ”, edited by the Japan Refrigeration Association Refrigerant Thermophysical Property Information Research Force Subcommittee, published by the Japan Refrigeration Association). Tend to be.

For this reason, in the conventional apparatus, when the amount of the liquid refrigerant accumulated in the accumulator 8 increases, the composition ratio of the mixed refrigerant circulating in the refrigeration cycle greatly changes from the composition of the sealed refrigerant, and the entire apparatus This causes a problem of reduced system efficiency. However, according to the configuration of the present invention, the amount of the liquid refrigerant accumulated in the accumulator 8 does not become too large, and as a result, the composition of the mixed refrigerant circulating in the refrigeration cycle changes significantly from the composition of the sealed refrigerant. Nothing.

The description of the above embodiment is for the purpose of describing the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Also, the configuration of each part of the present invention is not limited to the above-described embodiment,
It goes without saying that various modifications are possible within the technical scope described in the claims.

For example, in the description of the above embodiment, the second
Although the case where the container main body 16 is adjacent to the periphery of the compressor 2 has been described, the container main body 16 may be disposed close to the compressor main body 16 or may be configured to conduct heat with a heat medium.

[0028]

As described above, according to the present invention, a reduction in compression efficiency and damage to the compressor can be prevented with a simple structure without increasing the size and complexity of the entire apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an accumulator of a vapor compression refrigeration apparatus showing one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a refrigerant circuit of a conventional vapor compression refrigeration apparatus.

FIG. 3 is a Mollier diagram of a refrigeration cycle in a vapor compression refrigeration apparatus.

FIG. 4 is a schematic configuration diagram of an accumulator of a conventional vapor compression refrigeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Four-way valve 2 Compressor 3 Indoor heat exchanger 4 Indoor fan 5 Outdoor heat exchanger 6 Outdoor fan 7 Capillary tube 8 Accumulator 11 Container main body 12 Inflow pipe 13 Outflow pipe 14 Oil return hole 15 First container main body 16 Second container main body

Claims (4)

[Claims] 1. A vapor compression refrigeration system comprising a refrigeration cycle by connecting a compressor, a condenser, a decompressor, an evaporator, and an accumulator, wherein the accumulator stores the container body and the refrigerant from the evaporator in the container. An inflow pipe to be introduced into the main body, an outflow pipe for supplying a gas refrigerant gas-liquid separated in the container body to the compressor,
An oil return hole provided in the outflow pipe, for returning lubricating oil contained in the liquid gas-liquid separated in the container body to the compressor, wherein the container body is divided into a plurality, The oil return hole is provided so as to be located in the liquid in one container body,
A vapor compression refrigeration system wherein the liquid is heated using heat generated by a compressor. 2. The vapor compression refrigeration system according to claim 1, wherein said one container body is adjacent to a periphery of a compressor. 3. The container main body is divided into a first container main body and a second container main body having a smaller volume than the first container main body, and the second container main body is adjacent to a periphery of a compressor. The vapor compression refrigeration apparatus according to claim 1, wherein the oil return hole is provided so as to be located in the liquid in the second container body. 4. The vapor compression refrigeration system according to claim 1, wherein two or more non-azeotropic refrigerant mixtures are used as the working fluid.