WO2015173939A1

WO2015173939A1 - Refrigeration unit

Info

Publication number: WO2015173939A1
Application number: PCT/JP2014/063005
Authority: WO
Inventors: 寛也石原; 齊藤　信
Original assignee: 三菱電機株式会社
Priority date: 2014-05-15
Filing date: 2014-05-15
Publication date: 2015-11-19
Also published as: CN105917178B; CN105917178A; JP6359095B2; JPWO2015173939A1

Abstract

A refrigeration unit which has a refrigerant circuit that is configured by a compressor, a condenser, a main throttle unit, and an evaporator being connected by refrigerant piping, the refrigeration unit being equipped with: an oil separator that separates refrigerating machine oil from the refrigerant discharged from the compressor and is connected to a refrigerant pipe between the compressor and the condenser; an oil cooling portion that cools the refrigerating machine oil separated by the oil separator; and an oil return pipe that connects the refrigerating-machine-oil-outflow side of the oil separator and the compressor through the oil cooling portion. The oil cooling portion is provided integrally with the condenser and makes up 15% to 25% of the heat transfer area of the condenser.

Description

Refrigeration equipment

The present invention relates to a refrigeration apparatus equipped with a compressor.

The refrigeration apparatus includes, for example, a compressor, a heat source side heat exchanger that functions as a condenser, a throttling device, and a use side heat exchanger that functions as an evaporator, and these are connected by a refrigerant pipe. Those having a circuit have been proposed. Here, the compressor includes a compression mechanism having a compression chamber for compressing the refrigerant. For this reason, refrigerator oil is enclosed in the compressor in order to suppress wear of sliding parts of the compression mechanism.

The refrigerating machine oil sealed in the compressor is discharged from the discharge pipe of the compressor at a temperature equivalent to the refrigerant temperature discharged from the compressor. The refrigeration apparatus has a configuration in which the refrigeration oil discharged from the compressor is returned to the compressor via, for example, an oil return pipe. However, when the temperature of the refrigeration oil is returned to the compressor while the temperature is high, the refrigerant in the compressor is heated, so that the temperature of the refrigerant discharged from the compressor rises. When the temperature of the discharged refrigerant rises, the temperature exceeds the allowable temperature of the machine parts inside the compressor, causing a compressor failure. Moreover, if it returns to a compressor with the temperature of refrigerating machine oil still high, the refrigerant | coolant density of a compressor will reduce correspondingly, the work amount of a compressor will increase, and the power consumption of a compressor will increase. Thus, since there are various adverse effects when the refrigeration oil is returned to the compressor at a high temperature, various refrigeration apparatuses having a mechanism for cooling the refrigeration oil discharged from the compressor have been proposed ( For example, see Patent Documents 1 to 4).

The technique described in Patent Document 1 separates the refrigerant discharged from the compressor and the refrigerating machine oil with an oil separator, and flows the separated refrigerating machine oil through an auxiliary heat exchanger attached to the condenser. The auxiliary heat exchanger described in Patent Document 1 is an air-cooled type that cools the refrigeration oil by exchanging heat between the refrigeration oil and the air passing through the fins of the condenser.

The technique described in Patent Document 2 separates refrigeration oil discharged from a compressor with an oil separator, and flows the separated refrigeration oil through an oil return pipe passing through a condenser. The oil return pipe described in Patent Literature 2 is an air-cooled type that cools the refrigeration oil by exchanging heat between the refrigeration oil and the air passing through the condenser.

The technology described in Patent Document 3 separates refrigeration oil discharged from a compressor with an oil separator, and flows the separated refrigeration oil through an oil return circuit that passes through a condenser. The description in Patent Document 3 allows heat exchange between refrigerating machine oil and refrigerant in the condenser to return the refrigerating machine oil to the compressor, and also allows the refrigerant exchanged with refrigerating machine oil to be injected into the compressor. is there.

The technique described in Patent Document 4 includes an oil injection circuit having a cooling heat exchanger for cooling refrigeration oil separately from the condenser.

Japanese Patent Laid-Open No. 50-048536 (for example, refer to the drawings) Japanese Utility Model Publication No. 50-02493 (see, for example, FIG. 3) JP-A-5-340616 (see, for example, FIG. 1) JP 2009-257705 A (see, for example, abstract)

In the techniques described in

Patent Documents

1 and 2, a method of cooling refrigerator oil using a condenser is adopted. However, if the heat transfer area of the condenser of air and refrigerating machine oil is excessively divided for cooling the refrigerating machine oil, the heat dissipation performance of the condenser is lowered and the cooling performance of the refrigerating apparatus is reduced. On the other hand, if the heat transfer area of the condenser of air and refrigeration oil is excessively divided for the heat radiation of the refrigerant, the cooling of the refrigeration oil becomes insufficient, resulting in a failure of the compressor. That is, the techniques described in

Patent Documents

1 and 2 have a problem that it is impossible to achieve both suppression of reduction in cooling performance of the refrigeration apparatus and suppression of compressor failure.

In the technique described in Patent Document 3, a refrigerant flowing through a condenser is used for cooling the refrigerator oil. And the refrigerant | coolant which cooled refrigerator oil with the condenser is inject | poured into the part (intermediate stage) of the intermediate pressure of a compressor. For this reason, in the technique described in Patent Document 3, when a large amount of the refrigerant for injection is used for cooling the refrigerating machine oil, there is a problem that the temperature of the refrigerant for injection rises and the injection performance is reduced.

In the technique described in Patent Document 4, an oil injection circuit having a cooling heat exchanger is separately provided for cooling the refrigerator oil. For this reason, in the technique described in Patent Document 4, there is a problem that the manufacturing cost of the refrigeration apparatus increases by the amount of the heat exchanger for cooling and the like.

The present invention has been made to solve at least one of the above-described problems, and provides a refrigeration apparatus capable of achieving both suppression of cooling performance of a refrigeration apparatus and suppression of compressor failure. It is intended to provide.

A refrigerating apparatus according to the present invention is a refrigerating apparatus having a refrigerant circuit in which a compressor, a condenser, a main throttle device, and an evaporator are connected by a refrigerant pipe, and a refrigerant between the compressor and the condenser. An oil separator connected to the pipe for separating the refrigerant discharged from the compressor and the refrigerating machine oil; an oil cooling section for cooling the refrigerating machine oil separated in the oil separator; and a refrigerating machine oil outflow side of the oil separator; And an oil return pipe that connects the compressor via an oil cooling section. The oil cooling section is provided integrally with the condenser, and is 15% to 25% of the heat transfer area of the condenser. It occupies a range.

Since the refrigeration apparatus according to the present invention has the above-described configuration, it is possible to achieve both suppression of the cooling performance of the refrigeration apparatus and suppression of compressor failure.

1 is an example of a refrigerant circuit configuration of a refrigeration apparatus according to Embodiment 1 of the present invention. It is an example of the refrigerant circuit structure of the refrigeration apparatus which concerns on Embodiment 2 of this invention. It is an example of the refrigerant circuit structure of the refrigeration apparatus which concerns on Embodiment 3 of this invention. It is an example of the refrigerant circuit structure of the refrigeration apparatus which concerns on Embodiment 4 of this invention. It is an example of the refrigerant circuit structure of the refrigeration apparatus which concerns on Embodiment 5 of this invention. It is an example of the refrigerant circuit structure of the refrigeration apparatus which concerns on Embodiment 6 of this invention. It is an example of the refrigerant circuit structure etc. of the freezing apparatus which concerns on Embodiment 7 of this invention. 10 is an example of a refrigerant circuit configuration of a refrigeration apparatus according to Embodiment 8 of the present invention. It is explanatory drawing of the conventional freezing apparatus.

Embodiments of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is an example of a refrigerant circuit configuration of the refrigeration apparatus 100 according to Embodiment 1. The configuration of the refrigeration apparatus 100 will be described with reference to FIG.
The refrigeration apparatus 100 according to the present embodiment is provided with an improvement that can achieve both suppression of reduction in cooling performance of the refrigeration apparatus 100 and suppression of failure of the compressor 1.

[Description of configuration]
The refrigeration apparatus 100 includes a compressor 1 that compresses and discharges refrigerant, a condenser 2 (heat radiator) that condenses the refrigerant, a main throttle device 3 that decompresses the refrigerant, and an evaporator 4 that evaporates the refrigerant. is doing. The refrigeration apparatus 100 has a refrigerant circuit (refrigeration cycle) configured by connecting the compressor 1, the condenser 2, the main throttle device 3, and the evaporator 4 with a refrigerant pipe P. The refrigerating apparatus 100 is connected to an oil return pipe OP used to return the refrigerating machine oil to the compressor 1, and an oil separator 5 that separates the refrigerant from the refrigerating machine oil, and a heat exchanger 6 that functions as an economizer. And an economizer throttle device 7 for economizer. Furthermore, the refrigeration apparatus 100 includes a control unit 30 that controls the rotational speed of the compressor 1 and the like.

Here, the refrigerant pipe P includes a refrigerant pipe P1 that connects the discharge side of the compressor 1 and the oil separator 5, a refrigerant pipe P2 that connects the refrigerant outlet side of the oil separator 5 and the condenser 2, and condensation. And a refrigerant pipe P <b> 3 connecting the heat exchanger 2 and the heat exchanger 6. The refrigerant pipe P includes a refrigerant pipe P4 that connects the heat exchanger 6 and the main throttle device 3, a refrigerant pipe P5 that connects the main throttle device 3 and the evaporator 4, the evaporator 4 and the compressor 1. A refrigerant pipe P6 connecting the refrigerant suction side and an economizer pipe P7 connecting the refrigerant pipe P4 and the compressor 1 are provided. The economizer pipe P7 has one end connected to the refrigerant pipe P4 and the other end connected to the compressor 1 via the economizer expansion device 7 and the heat exchanger 6. The economizer pipe P7 has a configuration corresponding to the connection pipe.

Also, the oil return pipe OP is connected to the compressor 1 via the condenser 2 with one end side connected to the refrigerating machine oil outflow side of the oil separator 5. More specifically, the other end side of the oil return pipe OP is branched into one connected to a low-stage compression unit 1A side of the compressor 1 described later and one connected to the high-stage compression unit 1B side. Yes. For this reason, the refrigeration oil flowing through the oil return pipe OP is returned to each of the low-stage compression unit 1A and the high-stage compression unit 1B.

(Compressor 1)
The compressor 1 sucks a refrigerant, compresses the refrigerant, and discharges the refrigerant in a high temperature and high pressure state. The compressor 1 has a refrigerant discharge side connected to the oil separator 5 via a refrigerant pipe P1, and a refrigerant suction side connected to the evaporator 4 via a refrigerant pipe P6. In the refrigeration apparatus 100 according to the first embodiment, the compressor 1 is a two-stage screw compressor having a low-stage compressor 1A and a high-stage compressor 1B. That is, the refrigerant that has flowed into the compressor 1 flows into the low-stage compression unit 1A and is compressed to an intermediate pressure, and then flows into the high-stage compression unit 1B and is compressed to become high temperature and high pressure.

(Condenser 2)
The condenser 2 performs heat exchange between the high-temperature and high-pressure refrigerant discharged from the compressor 1 and the air. The condenser 2 is a heat exchanger on the heat source side. The condenser 2 has an upstream side connected to the oil separator 5 via the refrigerant pipe P2 and a downstream side connected to the heat exchanger 6 via the refrigerant pipe P3. The condenser 2 can be configured by, for example, a plate fin and tube heat exchanger that can exchange heat between the refrigerant flowing through the condenser 2 and the air passing through the fins. Further, the condenser 2 is provided with a condenser blower 2 </ b> A for supplying air that exchanges heat with the refrigerant supplied to the condenser 2. The rotation speed of the condenser blower 2 </ b> A is controlled by the control unit 30, and the amount of heat exchange between the refrigerant and the air in the condenser 2 can be changed.

The condenser 2 is connected to the condenser 2 such that the oil return pipe OP occupies a range of 15% to 25% of the heat transfer area of the condenser 2. Here, the part of the condenser 2 to which the oil return pipe OP is connected constitutes the oil cooling part 2B. That is, the oil cooling section 2B is provided integrally with the condenser 2 and occupies a range of 15% to 25% of the heat transfer area of the condenser 2. The heat transfer area of the condenser 2 includes the heat transfer area in the oil cooling unit 2B.

(Main diaphragm device 3)
The main throttle device 3 is for expanding the refrigerant, the upstream side is connected to the heat exchanger 6 via the refrigerant pipe P4, and the downstream side is connected to the evaporator 4 via the refrigerant pipe P5. is there. The main throttle device 3 can be composed of, for example, an electronic expansion valve whose opening degree is variable.

(Evaporator 4)
The evaporator 4 exchanges heat between the refrigerant decompressed by the main expansion device 3 and the air. The evaporator 4 is a use side heat exchanger. In addition, the evaporator 4 is comprised with the plate fin and tube type heat exchanger which can exchange heat between the refrigerant | coolant which flows through the evaporator 4, and the air which passes a fin similarly to the condenser 2, for example. Can do.

(Oil separator 5)
The oil separator 5 separates refrigerant and refrigeration oil. The oil separator 5 has an upstream side connected to the compressor 1 via a refrigerant pipe P1 and a downstream side connected to the condenser 2 via a refrigerant pipe P2. The oil separator 5 is connected to the condenser 2 on the outflow side of the refrigerating machine oil via the oil return pipe OP. That is, the refrigerating machine oil separated from the refrigerant by the oil separator 5 is returned to the compressor 1 after being cooled by the condenser 2.

(Heat exchanger 6)
The heat exchanger 6 is a heat exchanger that exchanges heat between the refrigerant and the refrigerant, and functions as an economizer of the refrigeration apparatus 100. The heat exchanger 6 includes a first flow path connected to the refrigerant pipe P3 and the refrigerant pipe P4, and a second flow path connected to the economizer pipe P7, and the refrigerant flowing through the first flow path It has a structure capable of exchanging heat with the refrigerant flowing through the second flow path.

The heat exchanger 6 can cool the refrigerant flowing through the first flow path by exchanging heat with the refrigerant flowing through the second flow path. Then, the cooled refrigerant is supplied to the evaporator 4 on the downstream side. The heat exchanger 6 has a function of improving the cooling performance of the refrigeration apparatus 100. That is, since the refrigeration apparatus 100 includes the heat exchanger 6, the power consumption of the compressor 1 increases, but the cooling performance (efficiency) is improved because the increase in the cooling capacity is large.

Moreover, the heat exchanger 6 is connected between the low stage compression part 1A and the high stage compression part 1B of the compressor 1 via the economizer piping P7. For this reason, the refrigerant | coolant which flows in into the high stage compression part 1B is the refrigerant | coolant compressed by the low stage compression part 1A, and the refrigerant | coolant supplied from the economizer piping P7. Here, the lower the refrigerant temperature, the more the compression work in the compressor 1 can be suppressed.
The refrigerant supplied from the economizer pipe P7 has a temperature lower than that of the refrigerant compressed by the low-stage compression unit 1A, and as a result, the refrigerant temperature supplied to the high-stage compression unit 1B can be suppressed. . For this reason, the refrigerant temperature discharged from the compressor 1 can be suppressed.

(Economizer squeezing device 7)
The economizer throttle device 7 is for expanding the refrigerant. The economizer expansion device 7 is provided between one end side of the refrigerant pipe P and the second flow path of the heat exchanger 6. The economizer throttling device 7 can be constituted by, for example, an electronic expansion valve whose opening degree is variable.

(Control unit 30)
Based on detection results of various sensors and the like, the control unit 30 rotates the rotation speed (including operation and stop) of the compressor 1, the condenser blower 2 </ b> A attached to the condenser 2, and the evaporator blower attached to the evaporator 4. The rotational speed of 4A (including operation and stop), the opening of the main throttle device 3, the opening of the economizer throttle device 7, and the like are controlled. In addition, this control part 30 can be comprised by control apparatuses, such as a microcomputer, for example.

[Refrigerant flow of refrigeration cycle of refrigeration apparatus 100]
The flow of the refrigerant flowing through the refrigerant circuit shown in FIG. 1 will be described with reference to FIG.
The gaseous refrigerant compressed and discharged by the compressor 1 flows into the oil separator 5 through the refrigerant pipe P1. The refrigerant that has flowed into the oil separator 5 is separated into refrigerant and refrigerating machine oil. The refrigerant in the oil separator 5 flows into the condenser 2 through the refrigerant pipe P2. The gaseous refrigerant that has flowed into the condenser 2 undergoes heat exchange with the air supplied from the condenser blower 2A attached to the condenser 2 to condense, and flows out of the condenser 2 as a high-pressure liquid refrigerant. .

The liquid refrigerant flowing out of the condenser 2 flows into the first flow path of the heat exchanger 6 functioning as an economizer through the refrigerant pipe P3, and is cooled by exchanging heat with the refrigerant flowing through the second flow path. . The refrigerant cooled in the first flow path of the heat exchanger 6 flows into the main expansion device 3 and is depressurized, and a part of the refrigerant flows into the economizer expansion device 7 and is depressurized.

The refrigerant decompressed by the main throttle device 3 flows into the evaporator 4 through the refrigerant pipe P5 and evaporates by exchanging heat with the air supplied from the evaporator blower 4A attached to the evaporator 4. The refrigerant flowing out of the evaporator 4 is sucked into the compressor 1 through the refrigerant pipe P6. The refrigerant sucked into the compressor 1 flows into the low stage compression unit 1A of the compressor 1 and is compressed.

The refrigerant decompressed by the economizer expansion device 7 flows into the second flow path of the heat exchanger 6 and exchanges heat with the refrigerant flowing through the first flow path, and then flows into the intermediate stage of the compressor 1. The refrigerant flowing into the intermediate stage of the compressor 1 flows into the high stage compression section 1B and is compressed together with the refrigerant compressed by the low stage compression section 1A.

[Flow of refrigerating machine oil of refrigeration apparatus 100]
The refrigerating machine oil in the compressor 1 is mixed with the refrigerant. For this reason, the refrigeration oil in the compressor 1 is discharged from the compressor 1 with a refrigerant | coolant. The high-temperature refrigeration oil discharged from the compressor 1 flows into the oil separator 5 and is separated from the refrigerant. The refrigerating machine oil in the oil separator 5 is supplied to the condenser 2 via the oil return pipe OP and cooled. The refrigerating machine oil cooled by the condenser 2 is returned to the low-stage compression unit 1A and the high-stage compression unit 1B of the compressor 1 through the oil return pipe OP, respectively. Thereby, even if a high temperature refrigerator oil flows out from the compressor 1, the refrigerating apparatus 100 can return to the compressor 1 after cooling refrigerator oil. Thereby, the refrigeration apparatus 100 can suppress wear of the sliding parts and the like constituting the low-stage compression unit 1A and the high-stage compression unit 1B.

[Effects of refrigeration apparatus 100 according to Embodiment 1]
The refrigerating apparatus 100 according to the first embodiment is connected to the condenser 2 so that the oil return pipe OP occupies a range of 15% to 25% of the heat transfer area of the condenser 2. is there. That is, the surface area of the fin of the condenser 2 to which the oil return pipe OP is connected occupies a range of 15% to 25% of the total surface area of the fin of the condenser 2.

When the surface area of the fins of the condenser 2 to which the oil return pipe OP is connected is smaller than 15% of the total surface area of the fins of the condenser 2, the cooling amount of the refrigerating machine oil becomes insufficient and the compressor 1 The temperature of the discharged refrigerant rises, and the compressor 1 is likely to fail. Further, when the surface area of the fin of the condenser 2 to which the oil return pipe OP is connected is larger than 25% of the total surface area of the fin of the condenser 2, the heat radiation amount of the refrigerant flowing through the condenser 2 is insufficient. As a result, the cooling performance of the refrigeration apparatus 100 is reduced.
In the refrigeration apparatus 100 according to the first embodiment, the fin surface area of the condenser 2 to which the oil return pipe OP is connected has a range of 15% to 25% of the total surface area of the fins of the condenser 2. Therefore, the suppression of the cooling performance of the refrigeration apparatus 100 and the suppression of the failure of the compressor 1 can both be achieved.

The refrigerating apparatus 100 according to Embodiment 1 separately cools the refrigerating machine oil by using a part of the condenser 2 without providing a heat exchanger for cooling the refrigerating machine oil. For this reason, the refrigerating apparatus 100 according to the first embodiment can suppress the manufacturing cost because a heat exchanger is not separately provided.

FIG. 9 is an explanatory diagram of a conventional refrigeration apparatus. As shown in FIG. 9, some conventional refrigeration apparatuses are provided with a sub heat exchanger 10 for cooling refrigeration oil separately from the condenser 2. In this conventional refrigeration apparatus, the sub heat exchanger 10 is connected to an injection pipe IJ through which a refrigerant flows and an oil return pipe OP that does not pass through the condenser 2. And in the heat exchanger 6, the supplied refrigerant | coolant and refrigerating machine oil heat-exchange, and refrigerating machine oil is cooled.

The refrigeration apparatus 100 according to Embodiment 1 is configured to cool the refrigeration oil with the air of the air-cooled condenser 2 instead of cooling the refrigeration oil with a refrigerant. For this reason, the amount of refrigerant circulating through the compressor 1, the condenser 2, the main throttle device 3, and the evaporator 4 can be prevented as much as the refrigerant (cooling refrigerant flowing through the injection pipe IJ) for cooling the refrigerating machine oil is unnecessary. . That is, in the refrigeration apparatus 100, the amount of refrigerant for injection is smaller than that in the conventional refrigeration apparatus, so that the refrigerant flowing through the condenser 2 is reduced. When the refrigerant flowing through the condenser 2 is reduced, the load on the condenser 2 is reduced, and even if the oil return pipe OP is connected to the condenser 2 and the heat transfer area between the refrigerant and the air in the condenser 2 is reduced, the condensation is performed. It is suppressed that the condensation temperature of the vessel 2 changes compared to the conventional case.

Embodiment 2. FIG.
FIG. 2 is an example of a refrigerant circuit configuration of the refrigeration apparatus 102 according to the second embodiment. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be mainly described. The refrigeration apparatus 102 according to the second embodiment supplies a refrigerant temperature sensor 9 that detects the refrigerant temperature discharged from the compressor 1, supplies liquid refrigerant to the compressor 1, and reduces the refrigerant temperature discharged from the compressor 1. An injection pipe IJ, and an injection throttle device 8 connected to the injection pipe IJ. The injection pipe IJ has a configuration corresponding to the connection pipe.

(Refrigerant temperature sensor 9)
The refrigerant temperature sensor 9 is used to detect the surface temperature of the refrigerant pipe P1. The refrigerant temperature sensor 9 has a detection unit (not shown) provided at the tip of the sensor. And the refrigerant | coolant temperature sensor 9 is arrange | positioned so that this detection part may contact the site | parts to measure, such as refrigerant | coolant piping P1, for example. The detection unit of the refrigerant temperature sensor 9 is connected to the control unit 30 by wiring or wirelessly. The method for detecting the temperature of the refrigerant flowing through the refrigerant pipe P1 by the refrigerant temperature sensor 9 is, for example, a method in which a resistance that varies depending on the temperature is built in the detection unit, and the control unit 30 performs an operation for converting the resistance value into temperature. Can be adopted.

(Injection piping IJ)
The injection pipe IJ has one end connected to the refrigerant pipe P4 and the other end connected to the compressor 1. Note that one end side of the injection pipe IJ is connected to the downstream side of the connection position of the economizer pipe P7, for example. An injection throttle device 8 is connected to the injection pipe IJ. The injection pipe IJ supplies the refrigerant cooled through the first flow path of the heat exchanger 6 functioning as an economizer to the compressor 1 and suppresses the refrigerant temperature discharged from the compressor 1. It is piping.

(Injection throttle device 8)
The injection throttle device 8 is for expanding the refrigerant. The injection throttle device 8 is provided in the injection pipe IJ. The injection throttle device 8 can be constituted by, for example, an electronic expansion valve whose opening degree is variable. The opening degree of the injection throttle device 8 is controlled by an opening degree control means 30B of the control unit 30 described later.

(Temperature determination means 30A and opening degree control means 30B)
The controller 30 determines whether or not the detection result of the refrigerant temperature sensor 9 is higher than, for example, a preset temperature T1, and the injection throttle device 8 based on the determination result of the temperature determination unit 30A. Opening degree control means 30B for controlling the opening degree. For example, when the temperature determination unit 30A determines that the detection result of the refrigerant temperature sensor 9 is higher than T1, the opening degree control unit 30B opens the injection throttle device 8. Thereby, a liquid refrigerant is supplied to the compressor 1 and the rise in the temperature of the refrigerant discharged from the compressor 1 can be suppressed.

[Effects of refrigeration apparatus 102 according to Embodiment 2]
The refrigeration apparatus 102 according to the second embodiment has the following effects in addition to the same effects as the refrigeration apparatus 100 according to the first embodiment. Since the refrigeration apparatus 102 includes the refrigerant temperature sensor 9, the injection pipe IJ, the injection throttle device 8, the temperature determination means 30A, and the temperature determination means 30A, the increase in the temperature of the refrigerant discharged from the compressor 1 is suppressed. Therefore, exceeding the allowable temperature of the machine parts inside the compressor 1 can be suppressed, and failure of the compressor 1 can be suppressed. That is, the refrigeration apparatus 102 according to the second embodiment has improved reliability by the amount that can suppress the failure of the compressor 1 and the like.

Although the refrigeration apparatus 102 according to the second embodiment has the injection pipe IJ, it does not have a structure (for example, a heat exchanger) for cooling the refrigeration oil connected to the injection pipe IJ. For this reason, the refrigerant for injection is not used for cooling of refrigeration oil. That is, in the refrigeration apparatus 102, it is possible to prevent an increase in the temperature of the refrigerant for injection, and it is possible to prevent a decrease in the injection performance.

Embodiment 3 FIG.
FIG. 3 shows an example of the refrigerant circuit configuration of the refrigeration apparatus 103 according to the third embodiment. In the third embodiment, the same reference numerals are given to configurations common to the first and second embodiments, and differences will be mainly described. The refrigeration apparatus 103 according to Embodiment 3 includes a sub heat exchanger 10 in addition to the configuration of the refrigeration apparatus 102 according to Embodiment 2. Further, in the refrigeration apparatus 103 according to Embodiment 3, it is not limited whether the oil return pipe OP occupies a range of 15% to 25% of the heat transfer area of the condenser 2. In the refrigeration apparatus 103 according to Embodiment 3, for example, the oil return pipe OP is less than 15% of the heat transfer area of the condenser 2.

(Sub heat exchanger 10)
The sub heat exchanger 10 can cool the refrigerating machine oil that could not be cooled by the condenser 2. The sub heat exchanger 10 is a heat exchanger that exchanges heat between the refrigerating machine oil and the refrigerant. The sub heat exchanger 10 has a first flow path connected to the oil return pipe OP and a second flow path connected to the injection pipe IJ, and the refrigerating machine oil flowing through the first flow path and the first flow path 2 has a structure capable of exchanging heat with the refrigerant flowing through the two flow paths.

[Effect of refrigeration apparatus 103 according to Embodiment 3]
The refrigeration apparatus 103 according to the third embodiment has the following effects in addition to the same effects as the

refrigeration apparatuses

100 and 102 according to the first and second embodiments. The refrigerating apparatus 103 according to the third embodiment has a sub heat exchanger 10 for auxiliary cooling in addition to the condenser 2 as a configuration for cooling the refrigerating machine oil, and uses the refrigerant for injection for cooling the refrigerating machine oil. . For this reason, when the refrigerant temperature discharged from the compressor 1 rises, the refrigerant temperature can be more easily lowered, and the reliability of the refrigeration apparatus 103 can be improved.

In the refrigeration apparatus 103 according to the third embodiment, the refrigeration oil is cooled in the condenser 2 before the refrigeration oil is cooled in the sub heat exchanger 10. For this reason, the refrigeration apparatus 103 according to the third embodiment suppresses an increase in the temperature of the refrigerant flowing through the injection pipe IJ, as compared with the case where the refrigeration oil is cooled only by the refrigerant flowing through the injection pipe IJ. Can do. For this reason, an increase in the temperature of the refrigerant injected into the compressor 1 can be suppressed, and an increase in the temperature of the refrigerant discharged from the compressor 1 can be suppressed.

That is, the refrigeration apparatus 103 according to the third embodiment cools the refrigeration oil in the sub heat exchanger 10 even when the cooling of the refrigeration oil in the condenser 2 is insufficient, and raises the temperature of the refrigerant flowing through the injection pipe IJ. It is possible to achieve both of suppressing the rise in the temperature of the refrigerant discharged from the compressor 1 by suppressing the above.

Embodiment 4 FIG.
FIG. 4 is an example of a refrigerant circuit configuration of the refrigeration apparatus 104 according to the fourth embodiment. In the fourth embodiment, components that are the same as those in the first to third embodiments are given the same reference numerals, and differences will be mainly described. The fourth embodiment is different from the second embodiment in that the injection pipe IJ for supplying the liquid refrigerant to the compressor 1 and the injection throttle device 8 are not provided.

The control unit 30 includes, in addition to the temperature determination unit 30A, an opening degree control unit 30C that controls the opening degree of the economizer expansion device 7 based on the determination result of the temperature determination unit 30A. For example, when the temperature determination unit 30A determines that the detection result of the refrigerant temperature sensor 9 is higher than T1, the opening degree control unit 30C further increases the opening degree of the economizer expansion device 7. Thereby, when the liquid refrigerant is not flowing through the economizer pipe P7, the liquid refrigerant flows. When the liquid refrigerant is flowing through the economizer pipe P7, the amount of the liquid refrigerant is increased. That is, the amount of liquid refrigerant supplied to the compressor 1 via the economizer pipe P7 can be increased, and the rise in the temperature of the refrigerant discharged from the compressor 1 can be suppressed.

[Effects of refrigeration apparatus 104 according to Embodiment 4]
The refrigeration apparatus 104 according to the fourth embodiment has the following effects in addition to the same effects as the

refrigeration apparatuses

100 and 102 according to the first embodiment. That is, the refrigeration apparatus 104 according to the fourth embodiment supplies liquid refrigerant to the compressor 1 to suppress an increase in the temperature of the refrigerant discharged from the compressor 1, and the injection pipe IJ and the injection throttle apparatus 8 It is possible to achieve both a reduction in manufacturing cost as much as provided.

Embodiment 5 FIG.
FIG. 5 is an example of the refrigerant circuit configuration of the refrigeration apparatus 105 according to the fifth embodiment. In the fifth embodiment, components that are the same as those in the first to fourth embodiments are given the same reference numerals, and differences will be mainly described. The refrigeration apparatus 105 according to the fifth embodiment has a sub heat exchanger 11 instead of the sub heat exchanger 10 of the refrigeration apparatus 103 according to the third embodiment. Unlike the third embodiment, the refrigeration apparatus 105 according to the fifth embodiment is not provided with the injection pipe IJ, the injection throttle device 8, and the refrigerant temperature sensor 9. In the refrigeration apparatus 105 according to the fifth embodiment, as in the third embodiment, whether the oil return pipe OP occupies a range of 15% to 25% of the heat transfer area of the condenser 2 is limited. Not. In the refrigeration apparatus 105 according to Embodiment 5, for example, the oil return pipe OP is less than 15% of the heat transfer area of the condenser 2.

(Sub heat exchanger 11)
The sub heat exchanger 11 can cool the refrigerating machine oil that could not be cooled by the condenser 2. The sub heat exchanger 11 is a heat exchanger that exchanges heat between the refrigerating machine oil and the refrigerant. The sub heat exchanger 11 has a first flow path connected to the oil return pipe OP and a second flow path connected to the economizer pipe P7, and the refrigerating machine oil flowing through the first flow path and the first flow path 2 has a structure capable of exchanging heat with the refrigerant flowing through the two flow paths.

[Effects of refrigeration apparatus 105 according to Embodiment 5]
The refrigeration apparatus 105 according to the fifth embodiment has the same effects as the refrigeration apparatus 100 according to the first embodiment.

Embodiment 6 FIG.
FIG. 6 is an example of a refrigerant circuit configuration of the refrigeration apparatus 106 according to the sixth embodiment. In the sixth embodiment, components that are the same as those in the first to fifth embodiments are given the same reference numerals, and differences will be mainly described. Unlike Embodiment 1, the refrigeration apparatus 106 according to Embodiment 6 includes an oil return pipe OP2 and an accumulator 12 that stores excess refrigerant. The refrigerating apparatus 106 according to the sixth embodiment cools the refrigerating machine oil with the accumulator 12 instead of cooling the refrigerating machine oil with the condenser 2. The oil return pipe OP2 has one end connected to the refrigeration oil outflow side of the oil separator 5 and the other end connected to the compressor 1 via the accumulator 12.

(Accumulator 12)
The accumulator 12 has one end connected to the evaporator 4 via the refrigerant pipe P6 and the other end connected to the suction side of the compressor 1 via the refrigerant pipe P8. The accumulator 12 has a container 12A for storing a liquid refrigerant. The oil return pipe OP2 is provided to exchange heat with the liquid refrigerant in the accumulator 2. Specifically, in the container 12A, for example, a part of the oil return pipe OP2 is disposed so as to approach the bottom side. That is, the oil return pipe OP2 is disposed so that the portion of the accumulator 12 in the container 12A is closer to the bottom side of the container 12A. Thereby, the oil return pipe OP2 is more reliably immersed in the liquid refrigerant stored in the container 12A, heat exchange between the liquid refrigerant and the refrigerating machine oil is promoted, and the refrigerating machine oil is cooled more efficiently.

[Effects of refrigeration apparatus 106 according to Embodiment 6]
The refrigerating apparatus 106 according to the sixth embodiment separately cools the refrigerating machine oil by using a part of the accumulator 12 without providing a heat exchanger for cooling the refrigerating machine oil. For this reason, the refrigeration apparatus 106 according to the sixth embodiment can reduce the manufacturing cost because a heat exchanger is not separately provided.

The refrigeration apparatus 106 according to the sixth embodiment can heat the liquid refrigerant in the accumulator 12 because a part of the oil return pipe OP2 is disposed in the container 12A of the accumulator 12. For this reason, it is possible to prevent the liquid refrigerant from flowing out from the accumulator 12 to the suction side of the compressor 1, that is, so-called liquid back. For this reason, the refrigeration apparatus 106 according to the sixth embodiment has improved reliability because the so-called liquid back can be suppressed.

The refrigeration apparatus 106 according to the sixth embodiment can store the liquid refrigerant in the accumulator 12, and can also heat the liquid refrigerant in the oil return pipe OP2. For this reason, even if the refrigerant in the two-phase state including the liquid refrigerant flows out of the evaporator 4 to improve the efficiency (performance improvement) of the evaporator 4 as a heat exchanger, the so-called liquid back is suppressed. be able to.

Embodiment 7 FIG.
FIG. 7 shows an example of a refrigerant circuit configuration of the refrigeration apparatus 107 according to the seventh embodiment. In the seventh embodiment, components that are the same as those in the first to sixth embodiments are given the same reference numerals, and differences will be mainly described. In the refrigeration apparatus 107 according to the seventh embodiment, an oil sump 13 is provided in the oil return pipe OP2 in addition to the configuration of the sixth embodiment.

(Oil sump 13)
The oil sump 13 is for stabilizing the amount of refrigerating machine oil returned to the compressor 1. The oil sump 13 can store refrigeration oil. The oil sump 13 is provided downstream of the accumulator 12 in the oil return pipe OP2 and upstream of the compressor 1.

[Effects of refrigeration apparatus 107 according to Embodiment 7]
The refrigeration apparatus 107 according to the seventh embodiment has the following effects in addition to the same effects as the refrigeration apparatus 106 according to the sixth embodiment. That is, the refrigeration apparatus 107 according to Embodiment 7 can stabilize the supply of refrigeration oil to the compressor 1 and can suppress the refrigeration oil from being exhausted by the compressor 1. Thereby, the refrigeration apparatus 107 according to the seventh embodiment can more reliably suppress the wear of the sliding parts constituting the compressor 1 and the reliability is improved.

Embodiment 8 FIG.
FIG. 8 shows an example of the refrigerant circuit configuration of the refrigeration apparatus 108 according to the eighth embodiment. In the eighth embodiment, components that are the same as those in the first to seventh embodiments are given the same reference numerals, and differences will be mainly described. In addition to the configuration of the first embodiment, the refrigeration apparatus 108 according to the eighth embodiment includes the refrigerant temperature sensor 9 provided in the refrigerant pipe P1. Furthermore, the refrigeration apparatus 108 according to Embodiment 8 includes a temperature determination unit 30A that determines whether or not the detection result of the refrigerant temperature sensor 9 is higher than, for example, a preset temperature T1, and the detection of the refrigerant temperature sensor 9. It has rotation speed control means 30D for controlling the rotation speed of the condenser blower 2A attached to the condenser 2 based on the result.

(Rotation speed control means 30D)
For example, when the temperature determination unit 30A determines that the detection result of the refrigerant temperature sensor 9 is higher than T1, the rotation speed control unit 30D increases the rotation speed of the condenser blower 2A. Thereby, much air is supplied to the condenser 2 and cooling of the refrigerating machine oil supplied to the condenser 2 through the oil return pipe OP can be promoted.

[Effects of refrigeration apparatus 108 according to Embodiment 8]
The refrigeration apparatus 108 according to the eighth embodiment has the following effects in addition to the effects of the refrigeration apparatus 100 according to the first embodiment. That is, the refrigeration apparatus 107 increases the rotation speed of the condenser blower 2A when the temperature of the refrigerant discharged from the compressor 1 rises above a preset temperature T1. For this reason, the temperature of the refrigerating machine oil returned to the compressor 1 can be lowered, and the refrigerant temperature discharged from the compressor 1 can be suppressed.

In addition, in this Embodiment 8, it demonstrated as what increases the rotation speed of 2 A of condenser fans. That is, when the temperature of the refrigerant discharged from the compressor 1 rises, the rotational speed of the condenser blower 2A at that time is increased. For example, the rotation speed of the condenser fan 2A may be maximized. Thereby, the refrigerant temperature discharged from the compressor 1 can be suppressed with higher efficiency.

In the eighth embodiment, the refrigerant circuit of the refrigeration apparatus 100 according to the first embodiment is used as the refrigerant circuit, but the refrigerant circuit is not limited thereto. The eighth embodiment can be similarly applied to the configurations of the second to fifth embodiments having a mechanism for cooling the refrigerating machine oil by the condenser 2.

1 Compressor, 1A Low stage compression section, 1B High stage compression section, 2 Condenser, 2A Condenser blower, 2B Oil cooling section, 3 Main throttle device, 4 Evaporator, 4A Evaporator blower, 5 Oil separator, 6 Heat exchanger, 7 economizer expansion device, 8 injection expansion device, 9 refrigerant temperature sensor, 10 sub heat exchanger, 11 sub heat exchanger, 12 accumulator, 12A container, 13 oil sump, 30 control unit, 30A temperature determination means, 30B Opening control means, 30C Opening control means, 30D Rotational speed control means, 100 Refrigeration apparatus, 102 Refrigeration apparatus, 103 Refrigeration apparatus, 104 Refrigeration apparatus, 105 Refrigeration apparatus, 106 Refrigeration apparatus, 107 Refrigeration apparatus, 108 Refrigeration apparatus, IJ injection pipe, OP oil return pipe, OP2 oil return pipe, P refrigerant pipe, P1 refrigerant pipe, P2 refrigerant pipe, P3 refrigerant pipe, P4 Refrigerant piping, P5 refrigerant piping, P6 refrigerant piping, P7 economizer piping, P8 refrigerant piping, T1 temperature.

Claims

A refrigeration apparatus having a refrigerant circuit configured by connecting a compressor, a condenser, a main throttle device, and an evaporator with refrigerant piping,
An oil separator which is connected to the refrigerant pipe between the compressor and the condenser and separates refrigerant discharged from the compressor and refrigerating machine oil;
An oil cooling section for cooling the refrigerating machine oil separated in the oil separator;
An oil return pipe connecting the refrigeration oil outflow side of the oil separator and the compressor via the oil cooling section;
With
The oil cooling section is
A refrigeration apparatus provided integrally with the condenser and occupying a range of 15% to 25% of a heat transfer area of the condenser.
A first flow path connecting the condenser and the main throttle device; and a second flow path connecting the compressor between the downstream side of the first flow path and the main throttle device. An economizer for exchanging heat between the refrigerant flowing through the first flow path and the refrigerant flowing through the second flow path;
One end side is connected to the downstream side of the first flow path of the economizer, and the other end side is connected to the compressor via the first flow path of the economizer;
One end side is connected to the downstream side of the first flow path of the economizer, and the other end side is an injection pipe connected to the compressor;
An injection throttle device provided in the injection pipe;
A refrigerant temperature sensor for detecting a temperature of the refrigerant pipe between the oil separator and a discharge side of the compressor;
The refrigeration apparatus according to claim 1, further comprising a control unit that controls an opening degree of the injection throttle device based on a detection result of the refrigerant temperature sensor.
A first flow path connecting the condenser and the main throttle device; and a second flow path connecting the compressor between the downstream side of the first flow path and the main throttle device. An economizer for exchanging heat between the refrigerant flowing through the first flow path and the refrigerant flowing through the second flow path;
One end side is connected to the downstream side of the first flow path of the economizer, and the other end side is connected to the compressor via the first flow path of the economizer;
An economizer throttle device provided in the economizer pipe;
A refrigerant temperature sensor for detecting a temperature of the refrigerant pipe between the oil separator and a discharge side of the compressor;
The refrigeration apparatus according to claim 1, further comprising a control unit that controls an opening degree of the economizer throttle device based on a detection result of the refrigerant temperature sensor.
A refrigeration apparatus having a refrigerant circuit configured by connecting a compressor, a condenser, a main throttle device, and an evaporator with refrigerant piping,
An oil separator which is connected to the refrigerant pipe between the compressor and the condenser and separates refrigerant discharged from the compressor and refrigerating machine oil;
An oil return pipe connecting the refrigeration oil outflow side of the oil separator and the compressor via the condenser;
A first flow path connecting the condenser and the main throttle device; and a second flow path connecting the compressor between the downstream side of the first flow path and the main throttle device. An economizer for exchanging heat between the refrigerant flowing through the first flow path and the refrigerant flowing through the second flow path;
One end side is connected between the condenser and the main throttle device, and the other end side is connected to the compressor, and a connection pipe;
A sub heat exchanger that is connected to the downstream side of the condenser and the connection pipe in the oil return pipe and exchanges heat between the refrigeration oil and the refrigerant,
A refrigeration apparatus.
In the connection pipe, one end side is connected to the downstream side of the first flow path of the economizer, and the other end side is an injection pipe connected to the compressor via the sub heat exchanger.
An injection throttle device connected to the upstream side of the sub heat exchanger in the injection pipe;
A refrigerant temperature sensor for detecting a temperature of the refrigerant pipe between the oil separator and a discharge side of the compressor;
The refrigeration apparatus according to claim 4, further comprising a control unit that controls an opening degree of the injection throttle device based on a detection result of the refrigerant temperature sensor.
One end side of the connection pipe is connected to the downstream side of the first flow path of the economizer, and the other end side is connected to the compressor via the second flow path of the economizer and the sub heat exchanger. In what is the economizer piping,
An economizer throttle device connected to the upstream side of the sub heat exchanger in the economizer piping;
A refrigerant temperature sensor for detecting a temperature of the refrigerant pipe between the oil separator and a discharge side of the compressor;
The refrigeration apparatus according to claim 4, further comprising a control unit that controls an opening degree of the economizer throttle device based on a detection result of the refrigerant temperature sensor.
A condenser blower that is attached to the condenser and that promotes heat exchange between the refrigerant and air supplied to the condenser;
The controller is
The rotation speed control means for increasing the rotation speed of the condenser blower when the temperature determination means determines that the temperature is higher than a preset temperature. 7. The refrigeration apparatus described in 1.
A refrigeration apparatus having a refrigerant circuit configured by connecting a compressor, a condenser, a main throttle device, and an evaporator with refrigerant piping,
An oil separator which is connected to the refrigerant pipe between the compressor and the condenser and separates refrigerant discharged from the compressor and refrigerating machine oil;
An accumulator connected between the evaporator and the suction side of the compressor and having a container for storing excess refrigerant in the refrigerant circuit;
An oil return pipe connecting the compressor oil outflow side of the oil separator and the compressor via the accumulator;
With
The oil return pipe is
A refrigeration apparatus provided to exchange heat with the liquid refrigerant in the accumulator.
The refrigeration apparatus according to claim 8, further comprising an oil sump that is provided downstream of the accumulator in the oil return pipe and stores refrigeration oil.
The compressor is
A low-stage compression section that compresses the refrigerant;
A high-stage compression section that compresses the refrigerant compressed by the low-stage compression section,
The oil return pipe is
10. The method according to claim 1, wherein the low-stage compression section and the high-stage compression section are connected to the low-stage compression section and the high-stage compression section so that refrigeration oil is supplied to each of the low-stage compression section and the high-stage compression section. The refrigeration apparatus according to claim 1.