JP2010112655A - Refrigeration equipment - Google Patents

Abstract

To control the temperature of a compressor suction portion of a refrigeration apparatus.
A refrigerant circuit (10) in which a main refrigerant circulates in a circuit in which a compressor (101), a condenser (102), an evaporator expansion valve (103), and an evaporator (104) are connected by refrigerant piping. The branch (201) between the condenser (102) and the evaporator expansion valve (103) is connected to the suction side connection (209) provided in the suction side piping of the compressor (101). A suction-side injection pipe (209), a split-flow refrigerant gasification mechanism (203) that gasifies the split refrigerant passing through the suction-side injection pipe (209), and a flow rate adjustment mechanism (202) that adjusts the flow rate of the split refrigerant. And a control unit that controls the flow rate adjustment mechanism (202) based on the temperature detected by the suction side temperature detection unit (401) provided in the suction side piping of the compressor (101) of the refrigerant circuit (10). (50 And, equipped with a.
[Selection] Figure 1

Description

  The present invention relates to a refrigeration apparatus in which the temperature of a suction portion of a compressor is controlled.

  If the discharge gas temperature of the compressor constituting the refrigerant circuit is excessively increased, the protection circuit may be activated to make the operation of the compressor unstable. In order to prevent such a situation, a liquid injection method is known as means for suppressing the discharge gas temperature (see, for example, Patent Document 1). In the liquid injection method, the liquid injection pipe is branched from the refrigerant pipe between the condenser of the refrigerant circuit and the evaporator expansion valve. The liquid injection pipe is connected to a refrigerant pipe on the suction side of the compressor. A part of the liquid refrigerant branched to the liquid injection pipe is directly returned to the compressor without passing through the evaporator, whereby the compressor is cooled and the discharge gas temperature is suppressed.

  FIG. 24 is a schematic diagram showing a conventional liquid injection type refrigeration apparatus 8. The refrigeration apparatus 8 includes a refrigerant circuit 10 and a liquid injection pipe 27.

  In the refrigerant circuit 10, a compressor 101, a condenser 102, an evaporator expansion valve 103, and an evaporator 104 are connected in this order by refrigerant piping. Hereinafter, the refrigerant circulating in the refrigerant circuit 10 is referred to as a mainstream refrigerant.

  The liquid injection pipe 27 branches from a branch part 201 between the condenser 102 and the evaporator expansion valve 103 and is connected to a liquid injection part 209 ′ provided in the suction side pipe of the compressor 101. In the middle of the liquid injection pipe 27, a liquid injection control valve 202 ', which is an expansion valve whose opening degree can be adjusted, is provided. The diversion refrigerant branched to the liquid injection pipe 27 is injected into a liquid injection unit 209 ′ provided on the suction side of the compressor 101. The amount of the divided refrigerant to be injected (hereinafter referred to as liquid injection refrigerant) is adjusted by increasing or decreasing the opening of the liquid injection control valve 202 '.

  FIG. 25 is a Mollier diagram (pressure-specific enthalpy diagram, ph diagram) showing a refrigeration cycle in the conventional liquid injection type refrigeration apparatus 8 shown in FIG.

  The mainstream refrigerant that is superheated steam is cooled by the liquid injection refrigerant in the liquid injection section 209 '. At this time, the enthalpy change of the mainstream refrigerant is from point J to point A in FIG. 25, and the enthalpy change of the liquid injection refrigerant is from point I to point A in FIG.

  The dryness of the liquid injection refrigerant at point I (weight ratio of gas-phase refrigerant to saturated refrigerant) X is in a liquid-rich state where X = 0.2. Therefore, there is a possibility that the liquid phase remains after the liquid injection refrigerant is mixed with the mainstream refrigerant in the liquid injection part 209 '. In that case, there is a possibility that an excessive load is applied to the compressor 101 due to liquid compression.

  Further, as described above, most liquid injection refrigerants are in a liquid phase. In the state where the liquid injection refrigerant is in the liquid phase and separated from the mainstream refrigerant, the cooling effect cannot be obtained. Therefore, in order to mix both, it is necessary to take the distance of the piping between the liquid injection part 209 'and the compressor 101.

Furthermore, as shown in FIG. 25, since the enthalpy difference between the liquid injection refrigerant (point I) and the main flow refrigerant (point J) is large, the cooling effect of the main flow refrigerant by the liquid injection refrigerant is too large, and the injection amount It is difficult to control. Therefore, the flow rate of the refrigerant passing through the liquid injection control valve 202 ′ becomes unstable and hunting of the liquid injection control valve 202 ′ is likely to occur.
Japanese Patent Laid-Open No. 11-94370

  In a refrigeration system used for general air-conditioning equipment, the refrigerant temperature in the suction portion of the compressor is about 45 ° C. at the maximum. In these refrigeration apparatuses, heat resistance is not required for the suction side piping, and resin components having a low heat resistance temperature may be used for the suction side piping.

  Here, for example, there are refrigeration apparatuses in which the refrigerant temperature in the suction portion of the compressor exceeds 100 ° C., such as a refrigeration apparatus (semiconductor chiller) used for cooling a semiconductor manufacturing apparatus. In such a refrigeration apparatus, when a resin component having a low heat resistant temperature is used for the piping component of the suction portion, the heat resistant temperature of the piping component may be exceeded. Therefore, in a refrigeration apparatus in which the temperature of the suction part becomes high, such as a semiconductor chiller, it is desirable to control not only the refrigerant temperature of the discharge part of the compressor but also the refrigerant temperature of the suction part of the compressor.

  However, in the conventional refrigeration apparatus, the temperature control of the suction portion of the compressor is not performed. Moreover, there is the above-mentioned problem when the temperature control on the suction side is to be performed by the conventional liquid injection method.

  The present invention has been made in view of such a conventional technical problem, and controls the injection amount of the conventional liquid injection method, compresses the liquid in the compressor, and between the suction side connection portion and the compressor. It is an object of the present invention to eliminate the problems related to the piping length of the refrigeration system and to control the temperature of the suction portion of the compressor of the refrigeration apparatus and protect the compressor from the overheating of the suction portion by the temperature control.

  A refrigeration apparatus according to the present invention includes, as a basic configuration, a compressor, a condenser, an evaporator expansion valve, a refrigerant circuit in which a mainstream refrigerant circulates in a circuit in which the evaporator is connected by a refrigerant pipe, and a condenser of the refrigerant circuit. And a refrigerant pipe connected to a suction side connection part, which is a connection part provided in the suction side pipe of the compressor, from a branch part between the main valve and the evaporator expansion valve. A suction-side injection pipe that is a refrigerant pipe into which a branch-flow refrigerant that is a branched refrigerant is injected into the suction-side connection portion, a branch-flow refrigerant gasification mechanism that gasifies the branch-flow refrigerant, and the branch flow in the suction-side injection pipe A flow rate adjusting mechanism that adjusts the flow rate of the refrigerant, a suction side temperature detection unit that is provided in a pipe on the suction side of the compressor of the refrigerant circuit, and that detects the temperature of the mainstream refrigerant passing through the pipe; Based on the temperature side temperature detection unit detects and a control unit for controlling the flow rate adjusting mechanism (claim 1).

  According to this aspect, the diverted refrigerant is injected into the suction side connecting portion, and the control portion controls the flow rate adjusting mechanism based on the temperature detected by the suction side temperature detecting portion. Therefore, since the temperature control of the suction portion of the compressor, which is not performed in the conventional liquid injection method and intermediate injection method, can be performed, overheating of the suction portion can be prevented.

  According to this aspect, the diverted refrigerant is gasified by the diverted refrigerant gasification mechanism and injected into the suction side connecting portion. Therefore, a gas refrigerant having a specific enthalpy larger than that of the liquid refrigerant injected by the conventional liquid injection method is injected into the suction side connecting portion. Therefore, the enthalpy difference between the mainstream refrigerant and the divided refrigerant to be injected becomes smaller than in the case of the liquid injection method, and the injection amount can be easily controlled.

  Further, according to this aspect, since the gasified diverted refrigerant is injected into the suction side connection portion, liquid compression in the compressor can be prevented, and suction for mixing the main flow refrigerant and the diverted refrigerant is performed. The distance of the piping between a side connection part and a compressor can be shortened.

  The flow rate adjusting mechanism is preferably an expansion valve whose opening degree can be adjusted. According to this aspect, the refrigerant flow rate can be easily controlled.

  The split refrigerant gasification mechanism is provided at a position between the condenser and the evaporator expansion valve in the refrigerant circuit and in the middle of the suction side injection pipe, and exchanges heat between the split refrigerant and the main refrigerant. A supercooling heat exchanger can be used (claim 3).

  Further, as the diverted refrigerant gasification mechanism, it is provided between the condenser and the evaporator expansion valve in the refrigerant circuit and at a position that becomes the branch portion, and a gas-liquid is provided inside or upstream of the diverted refrigerant gasification mechanism. A gas-liquid separator that includes a separation expansion valve and separates only the liquid refrigerant of the mainstream refrigerant that has passed through the gas-liquid separation expansion valve and sends it to the evaporator expansion valve can be used.

  According to these aspects, the refrigerant can be gasified with high energy efficiency as compared with the case where the refrigerant is gasified by heating with a heating means such as a heater.

  In the basic configuration, the refrigerant circuit (10) is a refrigerant circuit further comprising an economizer for improving COP between a condenser and an evaporator expansion valve of the refrigerant circuit, and the economizer further includes Located in the middle of the suction side injection pipe or at the branch portion, the diverted refrigerant gasification mechanism is the economizer, and the flow rate adjusting mechanism is capable of adjusting an opening degree for adjusting the flow rate of the refrigerant flowing into the economizer. It is an economizer control valve that is an expansion valve, branched from the suction side injection pipe, and connected to an intermediate injection part that is a connection part provided in the middle of the compression mechanism of the compressor, The gas phase refrigerant discharged from the economizer gas phase refrigerant discharge part is injected into the intermediate injection part. An intermediate injection pipe that is a refrigerant pipe; and a second flow rate adjusting mechanism that is provided in the refrigerant pipe between the branch part where the intermediate injection pipe is branched in the suction side injection pipe and the suction side connection part. Preferably, the control unit controls at least one of the economizer control valve and the second flow rate adjusting mechanism according to the temperature detected by the suction side temperature detection unit (Claim 5).

  According to this aspect, the suction portion of the compressor is simply added to the conventional intermediate injection type refrigeration apparatus by adding the suction side injection pipe and the second flow rate adjusting mechanism for adjusting the refrigerant flow rate of the suction side injection pipe. Temperature control becomes possible. Accordingly, it is possible to reduce the cost increase associated with the temperature control of the suction portion of the compressor.

  As the second flow rate adjusting mechanism, a suction side injection pipe opening / closing mechanism which is a flow path opening / closing mechanism can be used. According to this aspect, the gasified refrigerant can be injected into the suction side connection portion only when the suction portion of the compressor needs to be cooled.

  Further, as the second flow rate adjusting mechanism, an intake side injection control valve that is an expansion valve whose opening degree can be adjusted can be used. According to this aspect, the amount of refrigerant injected into the suction side connection can be controlled separately from the control of the economizer control valve, so that the temperature control of the suction portion of the compressor can be performed more precisely. Can do. Furthermore, by performing injection to both the suction side connection portion and the intermediate injection portion, the compressor can be cooled while minimizing the injection amount of the gas refrigerant. Therefore, damage to the compressor due to liquid compression can be more reliably prevented. And since intermediate injection is always performed, the COP improvement effect by an economizer is not impaired.

  In addition, a capillary tube can be used as the second flow rate adjusting mechanism (claim 8). According to this aspect, the second flow rate adjusting mechanism can be configured at low cost. And since intermediate injection is always performed, the COP improvement effect by an economizer is not impaired.

  Further, as the second flow rate adjusting mechanism, a capillary tube and a suction side injection pipe opening / closing mechanism which is a flow path opening / closing mechanism can be provided. According to this aspect, the gasified refrigerant can be injected into the suction side connection portion only when the suction portion of the compressor needs to be cooled. And since intermediate injection is always performed, the COP improvement effect by an economizer is not impaired.

  5. The refrigeration apparatus according to claim 1, wherein the suction side temperature detection unit is provided between a suction unit of the compressor and the suction side connection unit, and the suction unit of the compressor and the A low pressure detection unit that is provided in a pipe between the suction side connection unit and detects the pressure of the refrigerant in the pipe is further provided, wherein the control unit detects a temperature detected by the suction side temperature detection unit as a predetermined threshold value. In the above case, the flow rate adjusting mechanism is controlled so as to increase the flow rate of the diverted refrigerant, and when the temperature detected by the temperature detector (the temperature detected by the temperature detector is smaller than the threshold value), the temperature detected by the temperature detector Preferably, the degree of superheat of the suction part is calculated using the pressure detected by the low-pressure pressure detection part, and the flow rate adjusting mechanism is controlled so that the degree of superheat falls within a predetermined range. .

  According to this aspect, in addition to the temperature of the suction part of the compressor, the degree of superheat of the suction part is also controlled. Therefore, damage to the compressor due to liquid compression can be more reliably prevented.

  In the refrigeration apparatus using a suction side injection pipe opening / closing mechanism that is a flow path opening / closing mechanism as the second flow rate adjusting mechanism, the suction side temperature detection unit is provided between the suction unit of the compressor and the suction side connection unit. And a second temperature detection unit provided between the suction side connection unit and the evaporator, the suction unit of the compressor and the suction side connection unit, A low pressure detector that detects the pressure of the refrigerant in the pipe, and an intermediate injection temperature detector that is provided in the intermediate injection and detects the refrigerant temperature of the intermediate injection, An intermediate injection unit pressure detection unit that is provided in the intermediate injection unit and detects a refrigerant pressure of the intermediate injection unit, wherein the control unit is configured to detect the second temperature. When the detected temperature is equal to or higher than a predetermined first threshold value, the suction-side injection pipe opening / closing mechanism is opened until the temperature falls below a predetermined second threshold value that is smaller than the first threshold value. The superheat degree of the suction part is calculated using the temperature detected by the first temperature detection part and the pressure detected by the low pressure detection part so that the superheat degree of the suction part falls within a predetermined range. When the temperature detected by the second temperature detection unit is lower than the second threshold value, the temperature is equal to or higher than the first threshold value. Until that time, the suction-side injection pipe opening / closing mechanism is closed, and the intermediate injection unit is detected using the temperature detected by the intermediate injection unit temperature detection unit and the pressure detected by the intermediate injection unit pressure detection unit. The second temperature detection is performed by calculating the superheat degree of the intermediate portion and controlling the opening degree of the economizer control valve so that the superheat degree of the intermediate injection portion is within a predetermined range. When the temperature detected by the section is equal to or higher than the second threshold value and lower than the first threshold value, the suction side superheating degree control is performed when the suction side injection pipe opening / closing mechanism is open, and the suction side injection pipe is controlled. When the opening / closing mechanism is in the closed state, it is preferable to perform superheat control of the intermediate injection section (claim 11).

  According to this aspect, in addition to the temperature of the suction part of the compressor, the degree of superheat of the suction part and the intermediate injection part is also controlled. Therefore, damage to the compressor due to liquid compression can be more reliably prevented.

  In the refrigeration system using a suction side injection control valve that is an expansion valve whose opening degree can be adjusted as the second flow rate adjustment mechanism, the suction side temperature detection unit includes a suction unit of the compressor, and a suction side connection unit. When the temperature detected by the suction side temperature detection unit is equal to or higher than a predetermined threshold, the control unit adjusts the opening of the suction side injection control valve until the temperature becomes lower than the threshold. When the temperature detected by the suction side temperature detection unit is less than the threshold value, the opening degree of the suction side injection control valve is preferably decreased until the temperature becomes equal to or higher than the threshold value. 12).

  According to this aspect, the suction side injection control valve is feedback-controlled by the control unit according to the temperature detected by the suction side temperature detection unit. Therefore, the temperature of the suction part of the compressor can be reliably controlled below the threshold value.

  In the refrigeration apparatus using a capillary tube as the second flow rate adjusting mechanism, the suction side temperature detection unit is provided between the suction unit of the compressor and the suction side connection unit, and is provided in the intermediate injection unit. An intermediate injection part temperature detection part for detecting the refrigerant temperature of the intermediate injection part, and an intermediate injection part pressure detection part provided in the intermediate injection part for detecting the refrigerant pressure of the intermediate injection part, When the temperature detected by the suction side temperature detection unit is equal to or higher than a predetermined threshold, the control unit increases the opening of the economizer control valve until the temperature becomes lower than the first threshold, If the temperature detected by the suction side temperature detection unit is less than the threshold, the temperature detected by the intermediate injection unit temperature detection unit and The degree of superheat of the intermediate injection section is calculated using the pressure detected by the intermediate injection section pressure detection section, and the opening degree of the economizer control valve is set so that the superheat degree of the intermediate injection section falls within a predetermined range. Is preferably controlled (claim 13).

  According to this aspect, the economizer control valve is feedback-controlled by the control unit in accordance with the temperature detected by the suction side temperature detection unit. Therefore, the temperature of the suction part of the compressor can be reliably controlled below the threshold value. In addition, the economizer control valve is controlled so that the degree of superheat of the intermediate injection part is within a predetermined range regardless of the temperature of the suction part of the compressor. Therefore, damage to the compressor due to liquid compression can be reliably prevented.

  In the refrigerating apparatus including a capillary tube and a suction-side injection pipe opening / closing mechanism that is a flow path opening / closing mechanism as the second flow rate adjusting mechanism, the suction-side temperature detection unit includes the suction unit of the compressor and the suction unit A first temperature detection unit provided between the side connection unit and a second temperature detection unit provided between the suction side connection unit and the evaporator, and is provided in the intermediate injection unit. The intermediate injection unit temperature detecting unit for detecting the refrigerant temperature of the intermediate injection unit; and the intermediate injection unit pressure detecting unit provided in the intermediate injection unit for detecting the refrigerant pressure of the intermediate injection unit, When the temperature detected by the second temperature detection unit is equal to or higher than a predetermined first threshold value, the control unit is smaller than the first threshold value. A suction unit that controls the opening of the economizer control valve by using the temperature detected by the first temperature detection unit until the suction side injection pipe opening / closing mechanism is opened until the second threshold value is less than a predetermined second threshold value. When temperature control is performed and the temperature detected by the suction side temperature detector is less than the second threshold value, the suction side injection pipe opening / closing mechanism is closed until the temperature becomes equal to or higher than the first threshold value. And calculating the degree of superheat of the intermediate injection part using the temperature detected by the intermediate injection part temperature detection part and the pressure detected by the intermediate injection part pressure detection part. Performs superheat control of the intermediate injection section that controls the opening degree of the economizer control valve so as to be within the range, and detects the suction side temperature detection section When the temperature is equal to or higher than the second threshold value and lower than the first threshold value, the suction portion temperature control is performed when the suction side injection pipe opening / closing mechanism is open, and the suction side injection pipe opening / closing mechanism is closed. In the state, it is preferable to perform the superheat control of the intermediate injection part (claim 14).

  According to this aspect, the economizer control valve is feedback-controlled by the control unit in accordance with the temperature detected by the first temperature detection unit. Therefore, the temperature of the suction portion of the compressor can be reliably controlled within the range from the first threshold value to the second threshold value. In addition, the economizer control valve is controlled so that the degree of superheat of the intermediate injection part is within a predetermined range regardless of the temperature of the suction part of the compressor. Therefore, damage to the compressor due to liquid compression can be reliably prevented.

  The supercooling heat exchanger can be used as the economizer (claim 15).

  Moreover, the said gas-liquid separator can also be used as said economizer (Claims 16-19).

  A circuit provided separately from the refrigerant circuit, further comprising a brine circuit that cools the brine by exchanging heat between the brine in the circuit and the mainstream refrigerant in the refrigerant circuit using the evaporator. (Claim 20).

  According to this aspect, the object to be cooled is cooled not by the evaporator provided in the refrigerant circuit that executes the refrigeration cycle but by the brine circuit provided separately from the refrigerant circuit. Therefore, since the piping length of the refrigerant circuit can be suppressed, the apparatus can be miniaturized and the degree of freedom of the installation location of the refrigeration apparatus can be increased.

  Branched from a branch portion provided in a refrigerant pipe between the compressor and the condenser, and into a refrigerant pipe between the suction side connection part and the evaporator upstream of the suction side temperature detection part. You may make it further provide the hot gas bypass circuit which is a circuit connected (Claim 21).

  According to this aspect, the refrigerant discharged from the compressor is bypassed to the hot gas bypass circuit at the branch portion provided in the refrigerant pipe between the compressor and the condenser. Therefore, the amount of circulation of the mainstream refrigerant in the refrigerant circuit can be increased or decreased by increasing or decreasing the bypass flow rate of the mainstream refrigerant to the hot gas bypass circuit, so that the refrigeration capacity of the refrigerant circuit is easily changed. be able to.

  According to the refrigeration apparatus of the present invention, when compared with a conventional liquid injection type refrigeration apparatus, it is easy to control the injection amount, and liquid compression in the compressor is difficult to occur. There is an advantageous effect that the distance of the pipe between the suction side connecting portion for mixing and the compressor can be shortened. Furthermore, according to the refrigeration apparatus of the present invention, the temperature control of the suction part of the compressor, which is not done in the conventional refrigeration apparatus, is performed, and the suction part of the compressor is protected from overheating. Therefore, the reliability of the refrigeration apparatus in which the temperature on the suction side of the compressor becomes high is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 is a schematic diagram showing a refrigeration apparatus 1 according to an embodiment of the present invention. The refrigeration apparatus 1 is, for example, a refrigeration apparatus (semiconductor chiller) used for cooling a semiconductor manufacturing apparatus, and includes a refrigerant circuit 10, a suction-side injection pipe 20, a sensor group 40, a controller 50 (control unit), a brine circuit 60, a hot gas. A bypass circuit 70 is provided.

  The refrigerant circuit 10 is a circuit in which a compressor 101, a condenser 102, an evaporator expansion valve 103, and an evaporator 104 are connected in this order by refrigerant piping. As the refrigerant circulates in the refrigerant circuit 10 (hereinafter, the refrigerant circulating in the refrigerant circuit 10 is referred to as a mainstream refrigerant), a refrigeration cycle is executed.

  The compressor 101 is a scroll compressor provided with, for example, a scroll type compression mechanism. The compressor 101 compresses the low-temperature / low-pressure mainstream refrigerant vapor sent from the evaporator 104 into a high-temperature / high-pressure refrigerant vapor (see FIG. 3B, from point A to point D).

  The condenser 102 is, for example, a plate-type heat exchanger, and cools the high-temperature / high-pressure mainstream refrigerant discharged from the compressor 101 by exchanging heat between the mainstream refrigerant and, for example, cooling water. A high-pressure liquid refrigerant is used (see FIG. 3B), from point D to point E.

  The mainstream refrigerant that has been liquefied in the condenser 102 to become high-pressure liquid refrigerant passes through the supercooling heat exchanger 203. A part of the mainstream refrigerant that has passed through the supercooling heat exchanger 203 is diverted to the suction-side injection pipe 20. The subcooling heat exchanger 203 and the suction side injection pipe 20 will be described in detail later.

  The evaporator expansion valve 103 is an electronic expansion valve, for example, and can freely adjust the opening degree. The mainstream refrigerant in the high-pressure liquid refrigerant state becomes a low-temperature and low-pressure refrigerant by throttle expansion at the evaporator expansion valve 103 (see FIG. 3 (B), point F to point I), and is sent to the evaporator 104. The flow rate of the main refrigerant to the evaporator 104 is controlled by adjusting the opening degree of the evaporator expansion valve 103.

  The evaporator 104 is, for example, a plate heat exchanger, and exchanges heat between the brine flowing through the brine circuit 60 and the mainstream refrigerant. As a result, the mainstream refrigerant takes heat from the brine and evaporates, cooling the brine. The evaporated mainstream refrigerant becomes superheated steam that is in a superheated state than the saturation temperature (see FIG. 3B), and goes to the compressor 101.

  The suction side injection pipe 20 is branched from a branch part 201 provided in the refrigerant pipe between the condenser 102 and the evaporator expansion valve 103, and is a suction side which is a connection part provided in the suction side pipe of the compressor 101. It is a refrigerant pipe connected to the connection part 209. In the present embodiment, the branching portion 201 is provided between the supercooling heat exchanger 203 and the evaporator expansion valve 103 (rear branching), but is branched between the condenser 102 and the supercooling heat exchanger 203. Unit 201 may be provided (previous branch).

  A refrigerant branched from the mainstream refrigerant at the branching section 201 (hereinafter referred to as a branch flow refrigerant) passes through the suction-side injection pipe 20 and is injected into the suction-side connection section 209. The diverted refrigerant injected into the suction side connection unit 209 is hereinafter referred to as a suction side injection refrigerant. The suction side injection pipe 20 includes a supercooling heat exchanger control valve 202 and a supercooling heat exchanger 203.

  The supercooling heat exchanger control valve 202 is provided between the branch portion 201 of the suction side injection pipe 20 and the supercooling heat exchanger 203. The supercooling heat exchanger control valve 202 is an electronic expansion valve, for example, and the opening degree can be freely adjusted. The diverted refrigerant divided into the suction-side injection pipe 20 is expanded by the supercooling heat exchanger control valve 202 before flowing into the supercooling heat exchanger 203, the pressure and temperature are reduced, and the dryness X = 0.2. It becomes a liquid rich state. By adjusting the opening degree of the supercooling heat exchanger control valve 202, the flow rate of the refrigerant flowing into the supercooling heat exchanger 203 is controlled.

  The supercooling heat exchanger 203 is provided between the condenser 102 and the evaporator expansion valve 103 and in the middle of the suction side injection pipe 20. The supercooling heat exchanger 203 is, for example, a plate-type heat exchanger, and the main flow refrigerant that has become a high-pressure liquid refrigerant in the condenser 102 and the diversion flow whose temperature has been reduced by the expansion of the supercooling heat exchanger control valve 202. As a result of exchanging heat with the refrigerant, the sub-cooled refrigerant absorbs heat from the main-flow liquid refrigerant, so that the degree of supercooling of the main-flow refrigerant increases (see FIG. 3B). ). On the other hand, the diverted refrigerant that has absorbed heat from the mainstream liquid refrigerant becomes a gas-rich state with a dryness of about X = 0.8 and is discharged from the gas-phase refrigerant discharge portion of the supercooling heat exchanger 203.

  In the present embodiment, the main refrigerant and the diverted refrigerant flow in opposite directions (opposite flow) inside the supercooling heat exchanger 203 which is a plate heat exchanger, but the main refrigerant and The shunt refrigerant may flow in the same direction in the supercooling heat exchanger 203 (parallel flow).

  The sensor group 40 includes a pre-suction low temperature sensor 401 (suction side temperature detector) and a low pressure sensor 403 (low pressure detector).

  The pre-suction low temperature sensor 401 is a temperature sensor provided in the refrigerant pipe between the compressor suction part 109 and the suction side connection part 209. The pre-suction low-temperature sensor 401 detects the temperature of the refrigerant gas in which the mainstream refrigerant that has passed through the evaporator 104 and the suction-side injection refrigerant injected into the suction-side connection portion 209 are mixed.

  The low pressure sensor 403 is a pressure sensor provided in the refrigerant pipe between the compressor suction unit 109 and the suction side connection unit 209. The low-pressure sensor 403 detects the pressure of the refrigerant gas in which the mainstream refrigerant that has passed through the evaporator 104 and the suction-side injection refrigerant that has been injected into the suction-side connection portion 209 are mixed.

  The controller 50 performs operation control of the refrigeration apparatus 1 such as rotation speed control of the compressor 101 and opening degree control of the evaporator expansion valve 103. In the present embodiment, the temperature and superheat degree of the refrigerant passing through the compressor suction unit 109 are further controlled based on the temperature and pressure detected by the sensor group 40. The configuration of the controller 50 will be described in detail later.

  The brine circuit 60 is connected to the evaporator 104. The brine in the brine circuit 60 and the refrigerant in the refrigerant circuit 10 are heat-exchanged by the evaporator 104, whereby the brine in the brine circuit 60 that has cooled and absorbed heat is cooled by the object to be cooled.

  In addition to the refrigerant circuit 10 responsible for the refrigeration cycle, by providing the brine circuit 60 for cooling the object to be cooled, the piping length of the refrigerant circuit 10 can be suppressed, so that the unit of the refrigeration apparatus 1 can be downsized. There is an advantage that the degree of freedom of the installation place of the refrigeration apparatus 1 can be increased.

  The hot gas bypass circuit 70 is a circuit in which the mainstream refrigerant discharged from the compressor 101 is bypassed. The hot gas bypass circuit 70 is branched from a branch portion 701 provided in a refrigerant pipe between the compressor 101 and the condenser 102 and It is connected to a connection part 709 provided in the refrigerant pipe between the connection part 209 and the pre-suction low temperature sensor 401 upstream and to the evaporator 104. The refrigerant bypassed to the hot gas bypass circuit 70 merges with the mainstream refrigerant that has passed through the evaporator 104 at the connection portion 709 and heads toward the suction side connection portion 209.

  The hot gas bypass circuit 70 includes an expansion valve 702. The expansion valve 702 is an electronic expansion valve, for example, and the opening degree can be freely adjusted. The flow rate of the refrigerant bypassed to the hot gas bypass circuit 70 is adjusted by the controller 50 increasing or decreasing the opening degree of the expansion valve 702.

  The function of the hot gas bypass circuit 70 will be described with reference to FIGS. FIG. 2 is a diagram for explaining the function of the hot gas bypass circuit 70, and FIG. 2A is a schematic diagram illustrating an example of temperature control of the refrigerant and brine in which the hot gas bypass circuit 70 is removed from the refrigeration apparatus 1. FIG. 2B is a schematic diagram illustrating an example of temperature control of the refrigerant and brine in the refrigeration apparatus 1 including the hot gas bypass circuit 70. 3 is a Mollier diagram (pressure-specific enthalpy diagram (ph diagram)) showing the refrigeration cycle in the example of FIG. 2, and FIG. 3 (A) is an example of FIG. 2 (A). Correspondingly, FIG. 3B corresponds to the example of FIG. Note that the process of passing points A, D, E, F, and I in the Mollier diagrams of FIGS. 3A and 3B has already been described together with the configuration of the refrigeration apparatus 1 based on FIG. The description is omitted here.

  For example, there is a refrigeration apparatus such as a semiconductor chiller in which the temperature on the compressor suction side exceeds 100 ° C. In the example of the refrigeration apparatus 1 ′ having no hot gas bypass circuit in FIG. 2A, the brine flowing into the evaporator 104 at about 105 ° C. is set to be cooled to about 100 ° C. by about 5 ° C.

  The brine to be cooled, for example, an etching apparatus which is one of semiconductor manufacturing apparatuses and heated to 105 ° C. is heat-exchanged with the mainstream refrigerant in the evaporator 104 and cooled to a control target temperature of 100 ° C. The Conversely, the mainstream refrigerant is heated to about 100 ° C. (from point I to point J in FIG. 3A).

  The mainstream refrigerant heated to about 100 ° C. is about 40 in this example by the suction side injection refrigerant (point L in FIG. 3A) injected from the suction side injection pipe 20 at the suction side connection portion 209. It is cooled to 0 ° C. (from point J to point A in FIG. 3A).

  For example, a semiconductor chiller requires temperature control with higher accuracy and speed than general air-conditioning equipment. Providing a hot gas bypass circuit in the refrigeration apparatus is an effective means for satisfying this requirement.

  By providing the hot gas bypass circuit 70, the mainstream refrigerant circulating in the refrigerant circuit 10 can be bypassed. In the example of FIG. 2B, the refrigerant at about 100 ° C. discharged from the compressor 101 is branched to the hot gas bypass circuit 70 by the branching unit 701 and is throttled and expanded by the expansion valve 702 of the hot gas bypass circuit 70. Thus, it is cooled to about 80 ° C. (from point D to point K in FIG. 3B), and returned to the suction side of the compressor 101 at the connection portion 709.

  The refrigerant returned from the hot gas bypass circuit 70 (point K in FIG. 3B) joins the refrigerant from the evaporator 104 (point J in FIG. 3B) at the connection portion 709, and then connected to the suction side. The portion 209 is cooled by the suction-side injection refrigerant and travels toward the compressor suction portion 109 of the compressor 101. At this time, the enthalpy change of the merged refrigerant is from point K in FIG. 3B to point A, and the enthalpy change of the suction side injection refrigerant is from point L in FIG. 3B to point A. Note that the point indicating the merged refrigerant is K, because most of the discharge gas of the compressor 101 is bypassed to the hot gas bypass circuit 70, so that the specific enthalpy of the refrigerant after merging at the connection portion 709 is also almost the same. This is because it matches K.

  In the example of FIG. 2B, the control target temperature of the brine circuit 60 is set so that the brine flowing into the evaporator 104 at about 31 ° C. is cooled to 30 ° C. by about 1 ° C. In this case, the required amount of cooling is considerably lower than the cooling capacity of the semiconductor chiller. For this reason, if the compressor 101 is intermittently operated to reduce the circulation amount of the main refrigerant and suppress the refrigeration capacity, a time lag is generated due to the start and stop of the operation of the compressor 101, and high-precision temperature control is performed. It becomes difficult.

  Further, when the control target temperature of the brine circuit 60 is changed so that the brine flowing into the evaporator 104 at about 105 ° C. is cooled to about 5 ° C. to about 100 ° C., the main stream flowing into the evaporator 104 is changed. Since it is necessary to raise the refrigerant temperature from about 30 ° C. to about 100 ° C., rapid temperature control is also difficult when the hot gas bypass circuit 70 is not provided.

  Since the refrigeration apparatus 1 includes the hot gas bypass circuit 70, the primary refrigerant is bypassed to the hot gas bypass circuit 70, so that the amount of mainstream refrigerant circulating in the refrigerant circuit 10 can be reduced while the compressor 101 is continuously operated. The refrigeration capacity can be reduced. When it is desired to quickly raise the temperature of the main refrigerant flowing into the evaporator 104, the evaporator expansion valve (104) is fully closed, the expansion valve 702 of the hot gas bypass circuit 70 is opened, and the refrigerant circuit is opened. The refrigerant circulating through 10 is guided to the hot gas bypass circuit 70 to quickly raise the refrigerant temperature. When the evaporator expansion valve (104) is opened after the refrigerant temperature is raised in this manner, the heated mainstream refrigerant flows into the evaporator 104.

  When the evaporator expansion valve (104) is fully closed, high-temperature (80 ° C. in this example) refrigerant flows from the hot gas bypass circuit 70 into the compressor 101. Since the temperature of the machine discharge unit exceeds the heat resistance temperature, the compressor suction unit 109 and the compressor 101 are cooled by injecting the diverted refrigerant into the suction side connection unit 209.

  FIG. 4 is a block diagram illustrating a functional configuration of the controller 50. The controller 50 includes a microcomputer including a CPU (Central Processing Unit) and the like, and functions to include a system control unit 510 and a calculation unit 520.

  The system control unit 510 functions to include a refrigerant circuit control unit 511, a brine circuit control unit 512, a hot gas bypass circuit control unit 513, and a supercooling heat exchanger control valve control unit 514.

  The refrigerant circuit control unit 511 adjusts the flow rate of the mainstream refrigerant circulating in the refrigerant circuit 10 by controlling the rotation speed of the compressor 101 and the opening degree of the evaporator expansion valve 103.

  The brine circuit control unit 512 performs temperature control and flow rate control of the brine circulating in the brine circuit 60. The brine temperature control is provided in the brine circuit 60 when the temperature of the brine detected by the temperature sensor (not shown) provided at the outlet of the evaporator 104 of the brine circuit 60 is lower than the target value, for example. The brine is heated to the target value by heating the brine with the electric heater. This is because the refrigeration cycle by the refrigerant circuit 10 can only cool the brine. The flow control of the brine is performed by controlling the capacity of a pump provided in the brine circuit 60 and installed in an unillustrated tank that stores the brine.

  The hot gas bypass circuit control unit 513 controls the amount of refrigerant bypassed to the hot gas bypass circuit 70 after being discharged from the compressor 101 by increasing or decreasing the opening degree of the expansion valve 702.

  The subcooling heat exchanger control valve control unit 514 is configured such that the temperature Tls of the refrigerant gas passing between the compressor suction unit 109 and the suction side connection unit 209 detected by the low temperature sensor 401 before suction is a predetermined threshold, for example, 50. When the temperature is higher than or equal to ° C., the opening amount of the supercooling heat exchanger control valve 202 is increased until Tls becomes less than 50 ° C., thereby increasing the injection amount of the diverted refrigerant and lowering Tls.

  Further, the subcooling heat exchanger control valve control unit 514 controls the opening degree of the supercooling heat exchanger control valve 202 to divert to the compressor suction unit 109 when Tls is less than the threshold value of 50 ° C. By controlling the injection amount of the refrigerant, the degree of superheat LSH of the compressor suction unit 109 is controlled within a predetermined range.

  The shunt refrigerant discharged from the supercooling heat exchange economizer 203 is gas-rich compared to a liquid-rich refrigerant having a dryness of about 0.2, which is injected in the liquid injection method, but has a dryness of about 0.8. Including liquid phase refrigerant. Therefore, there is a possibility that the superheat degree is negative in the compressor suction portion 109, that is, the liquid refrigerant remains. In that case, liquid compression may occur in the compressor 101.

  Therefore, it is necessary to control the LSH to a positive value within a predetermined range so that the degree of superheat LSH of the compressor suction unit 109 does not become negative. By controlling the opening degree of the supercooling heat exchanger control valve 202 by the supercooling heat exchanger control valve control unit 514, the amount of suction side injection refrigerant injected into the suction side connection unit 209 is controlled, that is, LSH is in a predetermined range. Will be controlled. The LSH has a control target value of 5 ° C. and an allowable tolerance of ± 2 ° C., for example.

  The calculation unit 520 calculates the superheat degree LSH of the compressor suction unit 109 using the temperature Tls detected by the low temperature sensor 401 before suction and the pressure Pl detected by the low pressure sensor 403.

Since the degree of superheat is the difference between the actual discharge gas temperature and the temperature when the discharge gas is saturated (saturation temperature), LSH is defined by the following equation.
LSH = Tls-Tpl
Here, Tpl is a saturation temperature when the refrigerant gas passing through the compressor suction portion 109 is at the pressure Pl.

  FIG. 5 is a flowchart for explaining temperature control and superheat degree control of the compressor suction portion 109 in the refrigeration apparatus 1 according to the embodiment of the present invention.

  When the refrigeration apparatus 1 is activated, the controller 50 detects the temperature Tls of the refrigerant gas that passes between the compressor suction unit 109 and the suction side connection unit 209 detected by the low-temperature sensor 401 before suction as the threshold value, 50 ° C. It is determined whether it is above (step S1).

  When Tls is 50 ° C. or higher (YES in step S1), the supercooling heat exchanger control valve control unit 514 increases the opening degree of the supercooling heat exchanger control valve 202 in order to lower Tls. The injection amount of the shunt refrigerant is increased (step S2). Steps S1 and S2 are repeated until Tls becomes less than 50 ° C.

  When Tls is less than 50 ° C. (NO in step S1), the supercooling heat exchanger control valve control unit 514 controls the opening degree of the supercooling heat exchanger control valve 202 to suck into the suction side connection unit 209. The LSH is controlled within a predetermined range by controlling the side injection refrigerant amount. Here, it is assumed that the control target value of LSH is 5 ° C. and the allowable tolerance is ± 2 ° C., that is, LSH is controlled between 3 ° C. and 7 ° C.

  First, the calculation unit 520 uses the temperature Tls detected by the low temperature sensor 401 before suction and the pressure Pl detected by the low pressure sensor 403 to calculate LSH by the formula LSH = Tls−Tpl. When LSH is higher than 7 ° C. (YES in step S3), the supercooling heat exchanger control valve control unit 514 increases the opening degree of the supercooling heat exchanger control valve 202 and diverts to the suction side connection unit 209. The refrigerant injection amount is increased (step S4).

  When LSH is 7 ° C. or lower (NO in step S3), when 3 ° C. ≦ LSH ≦ 7 ° C. (YES in step S5), LSH is within the control target range, so the supercooling heat exchanger control valve control The unit 514 maintains the degree of opening of the supercooling heat exchanger control valve 202 and maintains the amount of refrigerant flowing into the suction side connection unit 209 (step S6).

  When LSH is less than 3 ° C. (NO in step S5), the supercooling heat exchanger control valve control unit 514 reduces the opening degree of the supercooling heat exchanger control valve 202 to divert refrigerant to the suction side connection unit 209. The injection amount is reduced (step S7).

  In any case of step S4, step S6, and step S7, the process returns to step S1 and temperature control of Tls is performed. In this way, step S1 to step S7 are repeated.

  In addition, although description was abbreviate | omitted, of course, also in this embodiment, the temperature of the refrigerant gas discharged from the compressor 101 is controlled similarly to the conventional freezing apparatus.

  According to the refrigeration apparatus 1 according to the first embodiment described above, the split refrigerant is gasified by the supercooling heat exchanger 203 and the connection part where the refrigerant gas is returned from the suction side connection part 209 and the hot gas bypass circuit 70. When the temperature with respect to 709 exceeds a predetermined value (50 ° C.), the diverted refrigerant is injected into the suction side connecting portion 209. Therefore, since the temperature control of the compressor suction part 109 which is not performed in the conventional refrigeration apparatus can be performed, the compressor suction part 109 can be prevented from being overheated.

  Further, according to the refrigeration apparatus 1 according to the first embodiment, since the gas refrigerant having a larger specific enthalpy than the liquid refrigerant injected by the conventional liquid injection method is injected into the suction side connecting portion 209, liquid injection Compared with the case of the system, the difference in enthalpy between the mainstream refrigerant and the divided refrigerant to be injected becomes small, and the injection amount can be easily controlled.

  Further, according to the refrigeration apparatus 1 according to the first embodiment, since the gasified diverted refrigerant is injected into the suction side connection unit 209, liquid compression in the compressor 101 can be prevented, and the mainstream refrigerant and the diverted refrigerant The distance of the piping between the suction side connection part 209 and the compressor 101 for mixing can be shortened. Further, since the degree of superheat of the compressor suction unit 109 is also controlled, liquid compression in the compressor 101 is further reliably prevented.

<Embodiment 2>
In the refrigeration apparatus 2 according to the present embodiment, the temperature control of the compressor suction portion 109 in the first embodiment is applied to a conventional intermediate injection type refrigeration apparatus. Hereinafter, the present embodiment will be described with reference to FIGS. In addition, about the point which is not different from Embodiment 1, description is abbreviate | omitted unless it is required.

  FIG. 6 is a schematic diagram showing the refrigeration apparatus 2 according to the second embodiment. Since it is an intermediate injection system, the refrigeration apparatus 2 includes an intermediate injection pipe 30 in addition to the configuration of the first embodiment, and the compressor 101 is an intermediate portion that is provided in the middle of the compression mechanism and into which a gas refrigerant is injected. An injection unit 309 is provided. The supercooling heat exchanger 203 in the first embodiment functions as an economizer that improves the COP of the refrigeration apparatus 2. Hereinafter, the supercooling heat exchanger 203 is referred to as a supercooling heat exchange economizer 203, and the supercooling heat exchanger control valve 202 is referred to as an economizer control valve 202. Further, the suction side injection pipe 21 of the refrigeration apparatus 2 includes a suction side injection pipe opening / closing mechanism 204 in addition to the suction side injection pipe 20 in the first embodiment.

  The suction-side injection pipe opening / closing mechanism 204 is provided between the branch portion 301 where the intermediate injection pipe 30 is branched from the suction-side injection pipe 21 and the suction-side connection portion 209. The suction-side injection pipe opening / closing mechanism 204 is, for example, a solenoid valve, and is in an open or closed state when energized.

  When the suction-side injection pipe opening / closing mechanism 204 is closed, the suction-side injection pipe 21 is closed, and all of the divided refrigerant flows to the intermediate injection pipe 30. Conversely, when the suction-side injection pipe opening / closing mechanism 204 is in the open state, the suction-side connection part 209 has a lower pressure than the intermediate injection part 309 to which the intermediate injection pipe 30 is connected, so that almost all of the divided refrigerant is present. Flows to the suction-side injection pipe 21.

  The intermediate injection pipe 30 is branched from a branch portion 301 between the supercooling heat exchange economizer 203 of the suction side injection pipe 21 and the suction side injection pipe opening / closing mechanism 204, and is connected to the intermediate injection section 309.

  The sensor group 41 of the refrigeration apparatus 2 includes a pre-intake low temperature temperature sensor 401 (first temperature detection unit) and a low pressure sensor 403 (low pressure detection unit), which are the configuration of the sensor group 40 of Embodiment 1, before injection. A low temperature sensor 402 (second temperature detector), an intermediate injection part temperature sensor 404 (intermediate injection part temperature detector), and an intermediate pressure sensor 405 (intermediate injection part pressure detector) are further provided.

  The pre-injection low-temperature sensor 402 is a temperature sensor provided in the refrigerant pipe between the suction-side connecting portion 209 and the connecting portion 709. The pre-injection low-temperature sensor 402 is configured so that the refrigerant bypassed to the hot gas bypass circuit 70 and returned to the connection portion 709 and the mainstream refrigerant that has passed through the evaporator 104 merge at the connection portion 709, and then the merged refrigerant is Then, the temperature before being cooled by the suction-side injection refrigerant is detected by the suction-side connection unit 209.

  The intermediate injection unit temperature sensor 404 is a temperature sensor provided in the intermediate injection unit 309 and detects the temperature of the refrigerant passing through the intermediate injection unit 309.

  The intermediate pressure sensor 405 is a pressure sensor provided in the intermediate injection unit 309 and detects the pressure of the refrigerant passing through the intermediate injection unit 309.

  FIG. 7 is a block diagram illustrating a functional configuration of the controller 51 included in the refrigeration apparatus 2. As in the first embodiment, the controller 51 functions to include a system control unit 510 and a calculation unit 520.

  The system control unit 510 functions to include a refrigerant circuit control unit 511, a brine circuit control unit 512, a hot gas bypass circuit control unit 513, an economizer control valve control unit 514, and an opening / closing mechanism control unit 515.

  The economizer control valve control unit 514 controls the economizer so that LSH or MSH falls within a predetermined range according to the superheat degree LSH of the compressor suction unit 109 calculated by the arithmetic unit 520 or the superheat degree MSH of the intermediate injection unit 309. The opening degree of the miser control valve 202 is controlled.

  When the suction-side injection pipe opening / closing mechanism 204 is in the closed state, all the diverted refrigerant flows into the intermediate injection pipe 30 as described above. Therefore, the MSH is set to a predetermined value so that the superheat degree MSH of the intermediate injection unit 309 does not become negative. When the suction side injection pipe opening / closing mechanism 204 is open, almost all of the divided refrigerant flows to the suction side injection pipe 21 as described above. It is necessary to control the LSH to a positive value within a predetermined range so that the degree of superheat LSH of the suction unit 109 does not become negative. The LSH has a control target value of 5 ° C. and an allowable tolerance of ± 2 ° C., for example. The MSH has a control target value of 5 ° C. and an allowable tolerance of ± 2 ° C., for example.

  The opening / closing mechanism control unit 515 controls opening / closing of the suction side injection pipe opening / closing mechanism 204. When the temperature Tlo detected by the pre-injection low temperature sensor 402 is equal to or higher than a predetermined first threshold, for example, 50 ° C., the opening / closing mechanism control unit 515 has a predetermined second threshold smaller than the first threshold. For example, the suction-side injection pipe opening / closing mechanism 204 is opened until the temperature falls below 40 ° C., and the suction-side injection pipe opening / closing mechanism 204 is closed when Tlo is less than 40 ° C. On the contrary, when Tlo is less than the predetermined second threshold value of 40 ° C., the suction-side injection pipe opening / closing mechanism 204 is closed until the first threshold value is 50 ° C. or more.

  As described above, the first threshold value is set to, for example, 50 ° C. and the second threshold value is set to, for example, 40 ° C. This is to avoid the occurrence of chattering.

  The calculation unit 520 uses the temperature Tms detected by the intermediate injection unit temperature sensor 404 and the pressure Pm detected by the intermediate pressure sensor 405 in addition to the calculation of LSH in the first embodiment, and the degree of superheat MSH of the intermediate injection unit 309. Is calculated.

MSH is defined by the following equation.
MSH = Tms-Tpm
Here, Tpm is a saturation temperature when the refrigerant gas passing through the intermediate injection unit 309 is at the pressure Pm.

  FIG. 8 shows the relationship between the opening / closing control of the suction side injection pipe opening / closing mechanism 204 by the opening / closing mechanism control unit 515 and the opening degree control of the economizer control valve 202 by the economizer control valve control unit 514, that is, the control of LSH and MSH. FIG.

  When the temperature Tlo of the refrigerant gas passing between the suction side connection portion 209 and the connection portion 709 detected by the pre-injection low temperature sensor 402 is 50 ° C. or more, which is the first threshold value, the opening / closing mechanism control unit 515 Then, the suction side injection pipe opening / closing mechanism 204 is opened. At this time, the economizer control valve control unit 514 controls the opening of the economizer control valve 202 to control the amount of suction-side injection refrigerant injected into the suction-side connection unit 209, that is, to control LSH (state B) ).

  In the state B where the suction side injection pipe opening / closing mechanism 204 is in the open state, when the Tlo decreases and becomes less than the second threshold value of 40 ° C., the opening / closing mechanism control unit 515 closes the suction side injection pipe opening / closing mechanism 204. State. At this time, the economizer control valve control unit 514 controls the opening degree of the economizer control valve 202 to control the amount of intermediate injection refrigerant injected into the intermediate injection unit 309, that is, control MSH within a predetermined range. (State A).

  In the state A where the suction side injection pipe opening / closing mechanism 204 is in the closed state, when Tlo becomes 50 ° C. or higher, the opening / closing mechanism control unit 515 opens the suction side injection pipe opening / closing mechanism 204 and shifts to the above state B. In this way, the refrigeration apparatus 2 takes one of the states A and B according to the temperature change of Tlo.

  FIG. 9 is a flowchart for explaining temperature control and superheat degree control of the compressor suction unit 109 and superheat degree control of the intermediate injection unit 309 in the refrigeration apparatus 2 according to the second embodiment.

  When the refrigeration apparatus 2 is activated, the controller 51 causes the temperature Tlo of the refrigerant gas passing between the suction side connection portion 209 and the connection portion 709 detected by the pre-injection low temperature sensor 402 to be the second threshold value. It is determined whether the temperature is 40 ° C. or higher (step S101).

  If Tlo is 40 ° C. or higher (YES in step S101), the controller 51 further determines whether Tlo is 50 ° C. or higher, which is the first threshold (step S1 ′). If Tlo is less than 40 ° C. (NO in step S101), the process proceeds to step S20. When Tlo is 50 ° C. or higher (YES in step S1 ′), the opening / closing mechanism control unit 515 opens the suction-side injection pipe opening / closing mechanism 204 (step S2 ′, state B in FIG. 8). If Tlo is less than 50 ° C. (YES in step S1 ′), the process proceeds to step S20.

  When the process proceeds to step S <b> 2 ′, the economizer control valve control unit 514 controls the degree of superheat LSH of the compressor suction unit 109 by controlling the opening degree of the economizer control valve 202. The control of LSH is the same as step S3 to step S7 of the first embodiment.

  Regardless of whether the process proceeds to step S4, step S6, or step S7, the controller 51 determines whether Tlo is 40 ° C. or higher (step S8). If Tlo is 40 ° C. or higher (YES in step S8), the process returns to step S3. If Tlo is less than 40 ° C. (NO in step S8), the process proceeds to step S20.

  If NO in step S101, NO in step S1 ', and NO in step S8, all proceed to step S20. In step S20, the opening / closing mechanism control unit 515 closes the suction side injection pipe opening / closing mechanism 204 (state A in FIG. 8).

  When it progresses to step S20, the economizer control valve control part 514 controls the superheat degree MSH of the intermediate injection part 309 by controlling the opening degree of the economizer control valve 202. Here, it is assumed that the MSH control target value is 5 ° C. and the tolerance is ± 2 ° C., that is, the MSH is controlled between 3 ° C. and 7 ° C. First, the calculation unit 520 uses the temperature Tms detected by the intermediate injection unit temperature sensor 404 and the pressure Pm detected by the intermediate pressure sensor 405 to calculate the superheat degree MSH of the intermediate injection unit 309 using the formula MSH = Tms−Tpm. calculate. If the MSH is higher than 7 ° C. (YES in step S21), the economizer control valve control unit 514 increases the opening of the economizer control valve 202 and increases the injection amount of the intermediate injection refrigerant to the intermediate injection unit 309. (Step S22).

  When MSH is 7 ° C. or lower (NO in step S21), when 3 ° C. ≦ MSH ≦ 7 ° C. (YES in step S23), since MSH is within the control target range, the economizer control valve control unit 514 The opening degree of the economizer control valve 202 is maintained (step S24).

  If the MSH is less than 3 ° C. (NO in step S23), the economizer control valve control unit 514 reduces the opening of the economizer control valve 202 to reduce the amount of intermediate injection refrigerant injected into the intermediate injection unit 309. (Step S25).

  In any of step S22, step S24, and step S25, the process returns to step S1 ', and the controller 51 determines whether or not Tlo is 50 ° C or higher. In this way, Step S1 'to Step S8 or Step S20 to Step S25 are repeated.

  In the refrigeration apparatus 2 according to the second embodiment described above, the suction side injection pipe 20 and the suction side injection pipe opening / closing mechanism 204 are only added to the conventional intermediate injection type refrigeration apparatus. Therefore, while maintaining the advantages of the conventional intermediate injection type refrigeration apparatus, it is possible to control the temperature of the compressor suction portion 109 while suppressing an increase in cost, and to prevent the compressor suction portion 109 from being overheated. Other operations and effects are the same as those in the first embodiment.

<Embodiment 3>
The refrigeration apparatus 3 according to the present embodiment differs from the second embodiment in that the suction-side injection pipe opening / closing mechanism 204 is replaced with a suction-side injection control valve 205 that is an expansion valve whose opening degree can be adjusted. Hereinafter, this embodiment will be described with reference to FIGS. Note that points that are not different from the first and second embodiments are not described unless necessary.

  FIG. 10 is a schematic diagram illustrating the refrigeration apparatus 3 according to the third embodiment, and FIG. 11 is a Mollier diagram illustrating a refrigeration cycle in the refrigeration apparatus 3. As described above, in the suction-side injection pipe 22 of the refrigeration apparatus 3, the suction-side injection control in which the suction-side injection pipe opening / closing mechanism 204 provided in the suction-side injection pipe 21 in the second embodiment is an expansion valve whose opening degree can be adjusted. Valve 205 has been replaced. By adopting this configuration, in the refrigeration apparatus 2, the opening degree of the economizer control valve 202 and the suction side injection control valve 205 can be adjusted. Accordingly, it is possible to simultaneously inject the diverted refrigerant into the suction side connection unit 209 and the intermediate injection unit 309.

  By injecting both the suction side connection part 209 and the intermediate injection part 309, the minimum gas refrigerant is injected into the suction side connection part 209 and the intermediate injection part 309, and the compressor is cooled. Therefore, the diversion refrigerants injected into the suction side connection part 209 and the intermediate injection part 309 all have a dryness of about 1 (points L and M in FIG. 11). Therefore, liquid phase refrigerant remains in the compressor suction part 109 and the intermediate injection part 309 of the compressor 101, and there is no possibility that the compressor 101 is damaged by liquid compression. Therefore, the superheat degree LSH of the suction side connection part 209 and the intermediate injection part Control of the superheat degree MSH of 309 is unnecessary.

  Based on FIG. 11, only the process different from Embodiment 1 is demonstrated below about the refrigerating cycle in the freezing apparatus 3. FIG.

  The refrigerant compressed on the low pressure side of the compression mechanism (from point A to point B in FIG. 11) is cooled by the intermediate injection refrigerant in the intermediate injection unit 309 before being compressed on the high pressure side of the compression mechanism. At this time, the enthalpy change of the mainstream refrigerant is from point B to point C in FIG. 8, and the enthalpy change of the intermediate injection refrigerant is from point M to point C in FIG. The mainstream refrigerant cooled by the intermediate injection refrigerant is further compressed on the high pressure side of the compression mechanism (from point C to point D in FIG. 11) and discharged from the compressor 101.

  The sensor group 41 of the refrigeration apparatus 3 includes a pre-suction low temperature sensor 401, an intermediate injection part temperature sensor 404, and an intermediate pressure sensor 405 (FIG. 10). As described above, the control of the superheat degree LSH of the suction side connecting portion 209 and the control of the superheat degree MSH of the intermediate injection portion 309 are unnecessary, and therefore only the temperature control of the compressor suction portion 109 may be performed. Therefore, only the pre-inhalation low-temperature sensor 401 is essential among the sensors constituting the sensor group of the second embodiment.

  FIG. 12 is a block diagram illustrating a functional configuration of the controller 52 included in the refrigeration apparatus 3. As in the first and second embodiments, the controller 52 functions to include a system control unit 510 and a calculation unit 520.

  The system control unit 510 functions to include a refrigerant circuit control unit 511, a brine circuit control unit 512, a hot gas bypass circuit control unit 513, an economizer control valve control unit 514, and a suction side injection control valve control unit 516. That is, the opening / closing mechanism control unit 515 in the refrigeration apparatus 2 according to the second embodiment is replaced with the suction side injection control valve control unit 516.

  The economizer control valve control unit 514 controls the opening degree of the economizer control valve 202. The economizer control valve control unit 514 is different from the refrigerating apparatus 2 according to the second embodiment in that the economizer control valve control unit 514 does not control the superheat degree LSH of the compressor suction unit 109 and the superheat degree MSH of the intermediate injection unit 309.

  The suction side injection control valve control unit 516 controls the opening degree of the suction side injection control valve 205. The suction-side injection control valve control unit 516 increases the opening of the suction-side injection control valve 205 to increase the Tls to 50 ° C. when the temperature Tls detected by the low temperature sensor 401 before suction is a predetermined threshold, for example, 50 ° C. or more. The injection amount of the branched refrigerant into the suction side connection portion 209 is increased so as to be less than the value. When Tls is less than the threshold value of 50 ° C., the opening degree of the suction side injection control valve 205 is decreased until the Tls becomes 50 ° C. or more, thereby reducing the injection amount of the branched refrigerant to the suction side connection portion 209. Let

  FIG. 13 is a flowchart for explaining temperature control of the compressor suction unit 109 in the refrigeration apparatus 2 according to the second embodiment.

  When the refrigeration apparatus 1 is activated, the controller 52 sets the temperature Tls of the refrigerant gas passing between the suction side connection unit 209 and the compressor suction unit 109 detected by the pre-suction low temperature sensor 401 to the threshold value 50. It is determined whether or not the temperature is equal to or higher than ° C. (step S1).

  If Tls is 50 ° C. or higher (YES in step S1), the suction side injection control valve control unit 516 increases the opening of the suction side injection control valve 205 so that Tls is less than 50 ° C. The amount of suction-side injection refrigerant injected into the unit 209 is increased (step S102).

  When Tls is less than 50 ° C. (NO in step S1), the suction-side injection control valve control unit 516 reduces the opening of the suction-side injection control valve 205 until the Tls becomes 50 ° C. or higher. The amount of branching refrigerant injected into the side connecting portion 209 is decreased (step S103). In both cases of step S102 and step S103, the process returns to step S1, and it is determined whether or not the temperature Tls is equal to or higher than the threshold value of 50 ° C. In this way, step S1 to step S103 are repeated.

  According to the refrigeration apparatus 3 according to the third embodiment described above, since the injection amount of the divided refrigerant to the suction side connection unit 209 can be controlled separately from the control of the economizer control valve 202, the compressor suction unit The temperature control 109 can be performed more precisely. In addition, since the intermediate injection is always performed, the COP improvement effect by the supercooling heat exchange economizer 203 is not impaired. Other operations and effects are the same as those in the second embodiment.

<Embodiment 4>
In the refrigeration apparatus 4 according to the present embodiment, the suction side injection pipe opening / closing mechanism 204 in the refrigeration apparatus 2 according to the second embodiment is replaced with a capillary tube 206. Hereinafter, the present embodiment will be described with reference to FIGS. In addition, about the point which is not different from Embodiment 1-3, description is abbreviate | omitted unless it is required.

  FIG. 14 is a schematic diagram showing the refrigeration apparatus 4 according to the fourth embodiment. As described above, in the suction side injection pipe 23 of the refrigeration apparatus 4, the suction side injection pipe opening / closing mechanism 204 provided in the suction side injection pipe 21 in the refrigeration apparatus 2 according to the second embodiment is squeezed and expanded with respect to the refrigerant passing therethrough. It is replaced by a capillary tube 206 that provides an action. The capillary tube 206 is a copper thin tube having an inner diameter of 0.6 to 2 mm, for example. The refrigerant passing through the capillary tube 206 is squeezed and expanded in the same manner as when passing through the expansion valve because the pressure of the refrigerant decreases due to fluid frictional resistance.

  By passing through the capillary tube 206 and gas refrigerant is injected into the suction side connection portion 209, a minimum amount of gas refrigerant is injected into the suction side connection portion 209 and the suction side connection portion 209 is cooled. Therefore, the shunt refrigerant injected into the suction side connection portion 209 has a dryness of about 1. That is, since the liquid phase refrigerant remains in the compressor suction portion 109 and there is no possibility that the compressor 101 is damaged by liquid compression, it is not necessary to control the degree of superheating LSH of the suction side connection portion 209.

  Further, as in the third embodiment, the diverted refrigerant is injected into both the suction side connection portion 209 and the intermediate injection portion 309, but in this embodiment, unlike the third embodiment, it passes through the capillary tube 206. The refrigerant flow rate cannot be controlled. That is, the suction side injection refrigerant quantity and the intermediate injection refrigerant quantity cannot be controlled independently. Therefore, since the amount of the intermediate injection refrigerant is not necessarily the minimum, the Mollier diagram showing the refrigeration cycle in the refrigeration apparatus 4 according to the present embodiment is different from the third embodiment in that the dryness of the intermediate injection refrigerant is 0. In the straight line QM in FIG. 11 indicating the path of enthalpy change of the intermediate injection refrigerant, the point M moves slightly to the left.

  Since the dryness of the intermediate injection refrigerant is about 0.8, the superheat degree MSH of the intermediate injection unit 309 is required. Therefore, the configuration of the sensor group 43 of the refrigeration apparatus 4 is the same as the configuration of the sensor group 42 of the third embodiment. The intermediate injection part temperature sensor 404 and the intermediate pressure sensor 405 are added (FIG. 14).

  As described above, the suction side injection refrigerant quantity and the intermediate injection refrigerant quantity cannot be controlled independently. That is, since the refrigerant flow rate in the capillary tube 206 needs to be adjusted by the opening degree of the economizer control valve 202, the control of the refrigeration apparatus 4 is different from the control of the refrigeration apparatus 3 according to the third embodiment. Therefore, the functional configuration of the controller 53 is also different from the controller 52 of the refrigeration apparatus 3.

  FIG. 15 is a block diagram illustrating a functional configuration of the controller 53 provided in the refrigeration apparatus 4. As in the first to third embodiments, the controller 53 functions to include a system control unit 510 and a calculation unit 520.

  The system control unit 510 functions to include a refrigerant circuit control unit 511, a brine circuit control unit 512, a hot gas bypass circuit control unit 513, and an economizer control valve control unit 514. That is, the opening / closing mechanism control unit 515 in the refrigeration apparatus 2 according to the second embodiment is omitted.

  The economizer control valve control unit 514 determines whether the Tls or MSH is in accordance with the temperature Tls of the compressor suction unit 109 detected by the pre-suction low temperature sensor 401 or the superheat degree MSH of the intermediate injection unit 309 calculated by the calculation unit 520. The opening degree of the economizer control valve 202 is controlled so as to be within a predetermined range.

  The economizer control valve control unit 514 opens the economizer control valve 202 so that the Tls is less than 50 ° C. when the temperature Tls detected by the low temperature sensor 401 before inhalation is equal to or higher than a predetermined threshold, for example, 50 ° C. The amount of the suction side injection refrigerant injected into the suction side connection portion 209 is increased at an increased rate. When Tls is less than the threshold value of 50 ° C., the economizer control valve control unit 514 reduces the opening of the economizer control valve 202 to the suction side connection unit 209 until Tls reaches 50 ° C. or more. The amount of suction-side injection refrigerant to be injected is reduced.

  Regardless of the value of Tls, the economizer control valve control unit 514 controls the opening amount of the economizer control valve 202 to control the amount of intermediate injection refrigerant injected into the intermediate injection unit 309, that is, MSH within a predetermined range. Control within. This MSH control is the same as in the second embodiment when the suction-side injection pipe opening / closing mechanism 204 is closed.

  FIG. 16 is a flowchart for explaining temperature control of the compressor suction unit 109 and superheat degree control of the intermediate injection unit 309 in the refrigeration apparatus 4 according to the fourth embodiment.

  When the refrigeration apparatus 4 is activated, the controller 53 has the above-mentioned threshold value as the temperature Tls of the refrigerant gas passing between the suction side connection portion 209 and the compressor suction portion 109 detected by the pre-suction low temperature sensor 401. It is determined whether the temperature is 50 ° C. or higher (step S1).

  If Tls is 50 ° C. or higher (YES in step S1), the economizer control valve control unit 514 increases the opening of the economizer control valve 202 so that Tls is less than 50 ° C. The amount of suction-side injection refrigerant injected into 209 is increased (step S2). Steps S1 and S2 are repeated until Tls becomes less than 50 ° C.

  When Tls is less than 50 ° C. (NO in step S1), the economizer control valve control unit 514 controls the opening degree of the economizer control valve 202 to control the intermediate injection refrigerant amount injected into the intermediate injection unit 309. As a result, the MSH is controlled within a predetermined range (after step S21). The control of this MSH is the same as in the second embodiment when the suction side injection pipe opening / closing mechanism 204 is closed (steps S21 to S25). In any of step S22, step S24, and step S25, the process returns to step S1, and the controller 53 determines whether Tls is 50 ° C. or higher. In this way, step S1 to step S25 are repeated.

  According to the refrigeration apparatus 4 according to the fourth embodiment described above, the suction side injection pipe opening / closing mechanism 204 using a mechanical opening / closing mechanism such as a solenoid valve is replaced with the capillary tube 206, so that the suction side injection can be performed at low cost. The temperature of the compressor suction portion 109 can be controlled by adjusting the flow rate of the pipe 22. In addition, since the intermediate injection is always performed, the COP improvement effect by the supercooling heat exchange economizer 203 is not impaired. Other operations and effects are the same as those in the second embodiment.

<Embodiment 5>
In the refrigeration apparatus 5 according to the present embodiment, the suction side injection pipe 23 in the refrigeration apparatus 4 according to the fourth embodiment is further changed to a suction side injection pipe 24 provided with a suction side injection pipe opening / closing mechanism 204. Hereinafter, the present embodiment will be described with reference to FIGS. In addition, about the point which is not different from Embodiment 1-4, description is abbreviate | omitted unless it is required.

  FIG. 17 is a schematic diagram illustrating the refrigeration apparatus 5 according to the fifth embodiment. As described above, the suction-side injection pipe 24 of the refrigeration apparatus 5 takes either the open state or the closed state in addition to the capillary tube 206 of the suction-side injection pipe 23 in the refrigeration apparatus 4 according to Embodiment 4. For example, a suction side injection pipe opening / closing mechanism 204 that is a solenoid valve is provided. In FIG. 17, the suction-side injection pipe opening / closing mechanism 204 is provided between the capillary tube 206 and the suction-side connecting portion 209, but the suction-side injection pipe opening / closing mechanism 204 is replaced by the intermediate injection pipe 30 that is the suction-side injection pipe 24. It may be provided between the branch portion 301 branched from the capillary tube 206 and the capillary tube 206.

  Since there is no difference that the diverted refrigerant that is branched at the branching portion 201 and passes through the supercooling heat exchange economizer 203 and injected into the suction side connecting portion 209 passes through the capillary tube 206, as in the fourth embodiment, Control of the superheat degree LSH of the suction side connection part 209 is unnecessary.

  The sensor group 44 of the refrigeration apparatus 5 includes a pre-intake low temperature temperature sensor 401 (first temperature detection unit), a pre-injection low temperature temperature sensor 402 (second temperature detection unit), and an intermediate injection unit temperature sensor 404 (intermediate injection unit temperature detection unit). ), An intermediate pressure sensor 405 (intermediate injection section pressure detection section).

  Moreover, since the said branch flow refrigerant | coolant is always inject | poured into the intermediate injection part 309 as an intermediate injection refrigerant | coolant, the Mollier diagram which shows the refrigerating cycle in the freezing apparatus 5 which concerns on this embodiment is also the same as that of Embodiment 4.

  FIG. 18 is a block diagram illustrating a functional configuration of the controller 54 included in the refrigeration apparatus 5. As in the first to fourth embodiments, the controller 54 functions to include a system control unit 510 and a calculation unit 520.

  The system control unit 510 functions to include a refrigerant circuit control unit 511, a brine circuit control unit 512, a hot gas bypass circuit control unit 513, an economizer control valve control unit 514, and an opening / closing mechanism control unit 515. That is, the suction side injection control valve control unit 516 in the refrigeration apparatus 3 according to the third embodiment is replaced with the opening / closing mechanism control unit 515.

  The economizer control valve control unit 514 makes Tls or MSH within a predetermined range according to the temperature Tls detected by the low temperature sensor 401 before suction or the superheat degree MSH of the intermediate injection unit 309 calculated by the calculation unit 520. The opening degree of the economizer control valve 202 is controlled.

  That is, the economizer control valve control unit 514 increases / decreases the opening of the economizer control valve 202 to control Tls so that it is within a predetermined range when the suction-side injection pipe opening / closing mechanism 204 is open, When the suction side injection pipe opening / closing mechanism 204 is closed, the MSH is controlled to be within a predetermined range. The MSH control is the same as that in the first embodiment when the suction-side injection pipe opening / closing mechanism 204 is closed.

  The opening / closing mechanism control unit 515 controls opening / closing of the suction side injection pipe opening / closing mechanism 204. When the temperature Tlo detected by the pre-injection low temperature sensor 402 is a predetermined first threshold, for example, 50 ° C. or more, the opening / closing mechanism control unit 515 has a predetermined second threshold that is smaller than the first threshold. For example, the suction-side injection pipe opening / closing mechanism 204 is opened until the temperature becomes less than 40 ° C., and when the Tlo is less than 40 ° C., the suction-side injection pipe opening / closing mechanism 204 is closed.

  FIG. 19 is a flowchart for explaining temperature control of the compressor suction unit 109 and superheat degree control of the intermediate injection unit 309 in the refrigeration apparatus 5 according to the fifth embodiment.

  When the refrigeration apparatus 5 is activated, the controller 54 has the temperature Tlo of the refrigerant gas passing between the suction side connection portion 209 and the connection portion 709 detected by the pre-injection low temperature sensor 402 as the second threshold value 40. It is determined whether the temperature is equal to or higher than ° C. (step S101).

  If Tlo is 40 ° C. or higher (YES in step S101), the controller 54 further determines whether Tlo is 50 ° C. or higher, which is the first threshold (step S1 ′). If Tlo is less than 40 ° C. (NO in step S101), the process proceeds to step S20. When Tlo is 50 ° C. or higher (YES in step S1 ′), the opening / closing mechanism control unit 515 opens the suction side injection pipe opening / closing mechanism 204 (step S2 ′). If Tlo is less than 50 ° C. (NO in step S1 ′), the process proceeds to step S20.

  When the process proceeds to step S2 ′, the controller 54 determines whether the temperature Tls of the refrigerant gas passing between the compressor suction portion 109 and the suction side connection portion 209 detected by the low temperature sensor 401 before suction is 40 ° C. or higher. The economizer control valve control unit 514 controls Tls by controlling the opening degree of the economizer control valve 202 (step S3 ′). When Tls is 40 ° C. or more (YES in step S3 ′), the economizer control valve control unit 514 increases the opening of the economizer control valve 202 so that Tls is less than 40 ° C. The injection amount of the branched refrigerant to 209 is increased (step S4).

  When Tls is less than 40 ° C. (NO in step S3 ′), the economizer control valve control unit 514 reduces the opening of the economizer control valve 202 until Tls becomes 40 ° C. or higher. The injection amount of the branched refrigerant to 209 is decreased (step S7).

  Regardless of whether the process proceeds to step S4 or step S7, the controller 54 determines whether Tlo is 40 ° C. or higher (step S8).

  If Tlo is 40 ° C. or higher (YES in step S8), the process returns to step S3 ′ and the controller 54 determines whether Tls is 40 ° C. or higher. If Tlo is less than 40 ° C. (NO in step S8), the process proceeds to step S20.

  If NO in step S101, NO in step S1 ', or NO in step S8, the process proceeds to step S20. In step S20, the opening / closing mechanism control unit 515 closes the suction side injection pipe opening / closing mechanism 204.

  When it progresses to step S20, the economizer control valve control part 514 controls the superheat degree MSH of the intermediate injection part 309 by controlling the opening degree of the economizer control valve 202. The control of this MSH is the same as in the second embodiment when the suction side injection pipe opening / closing mechanism 204 is closed (steps S21 to S25). In any of step S22, step S24, and step S25, the process returns to step S1 ', and the controller 54 determines whether or not Tlo is 50 ° C or higher. In this way, step S1 'to step S25 are repeated.

  According to the refrigeration apparatus 5 according to the fifth embodiment described above, by providing the suction side injection pipe opening / closing mechanism 204, the divided refrigerant is injected into the suction side connection part 209 only when the compressor suction part 109 needs to be cooled. can do. In addition, since the intermediate injection is always performed, the COP improvement effect by the supercooling heat exchange economizer 203 is not impaired. Other operations and effects are the same as those in the second embodiment.

  As mentioned above, although the refrigeration apparatuses 1-5 which concern on Embodiment 1-5 of this invention were demonstrated, this invention is not limited to this, For example, the following modified embodiment can also be taken.

  (1) Although the supercooling heat exchange economizer is used as the economizer in Embodiments 2 to 5, a gas-liquid separation economizer can be used instead.

  The gas-liquid separation economizer is provided between the condenser and the evaporator expansion valve in the refrigerant circuit, and has a gas-liquid separation expansion valve inside or upstream thereof, and the liquid-phase refrigerant of the refrigerant that has passed through the gas-liquid separation expansion valve It is an economizer that improves the COP by separating only the gas and sending it to the evaporator expansion valve.

  An example in which the supercooling heat exchange economizer 203 in the second and third embodiments is replaced with a gas-liquid separation economizer 203 'is shown in FIGS. 20 and 22, respectively. The gas-liquid separation economizer 203 ′ is located at the branching portion 201 in the second and third embodiments. In these examples, an economizer control valve 202 is provided in the refrigerant pipe between the condenser 102 of the refrigerant circuit 10 and the gas-liquid separation economizer 203 ′, and the economizer control valve 202 is the gas-liquid separation expansion valve. Is functioning as A Mollier diagram corresponding to the refrigeration cycle in the refrigeration apparatus 6 shown in FIG. 20 is shown in FIG. 21, and a Mollier diagram corresponding to the refrigeration cycle in the refrigeration apparatus 7 shown in FIG. FIG. 21 is a Mollier diagram when the suction side injection pipe opening / closing mechanism 204 is in an open state.

Based on FIG. 22 and FIG. 23, the reason why the gas-liquid separation economizer 203 ′ improves the COP will be described.

  The high-pressure liquid refrigerant that has passed through the condenser 102 is squeezed and expanded to an intermediate pressure by the economizer control valve 202, and the pressure is reduced (point E to point G in FIG. 23). Refrigerant vapor (point P in FIG. 23) generated by this decompression is discharged from the gas-phase refrigerant discharge portion of the gas-liquid separation economizer 203 ′ and travels to the intermediate injection portion 309. Only the remaining main liquid refrigerant in the saturated liquid state (point H in FIG. 23) is squeezed and expanded to a low pressure by the evaporator expansion valve 103 and travels toward the evaporator 104 (from point H to point I in FIG. 23).

  The mainstream refrigerant compressed on the low pressure side of the compression mechanism (from point A to point B in FIG. 23) is cooled by the intermediate injection refrigerant in the intermediate injection unit 309 before being compressed on the high pressure side of the compression mechanism. At this time, the enthalpy change of the main refrigerant is from point B to point C in FIG. 23, and the enthalpy change of the intermediate injection refrigerant is from point P to point C in FIG. The mainstream refrigerant cooled by the intermediate injection refrigerant is further compressed on the high pressure side of the compression mechanism (from point C to point D in the figure) and discharged from the compressor 101.

  In the absence of the gas-liquid separation economizer 203 ', the enthalpy at the inlet of the evaporator 104 is point I' in FIG. By providing the gas-liquid separation economizer 203 ', the enthalpy difference at the inlet / outlet of the evaporator 104 is increased by (I-I'), so that the COP is improved.

  Note that FIG. 21 is a Mollier diagram when the suction-side injection pipe opening / closing mechanism 204 is in the open state, so that almost no refrigerant is injected into the intermediate injection unit 309 as described in the second embodiment. Therefore, unlike FIG. 23, the path of change in the enthalpy of the intermediate injection refrigerant represented by points P to C in FIG. 23 is lacking.

  When the supercooling heat exchange economizer 203 is replaced with a gas-liquid separation economizer 203 ′, the refrigerant injected into the suction side connection portion 209 and the intermediate injection portion 309 are both gas-phase separated gas-phase refrigerants. Therefore, the dryness is 1 (FIGS. 21 and 23). Therefore, it is not necessary to control the LSH and the MSH, and only the temperature control of the compressor suction unit 109 may be performed. Therefore, only the pre-inhalation low-temperature sensor 401 is required among the sensors constituting the sensor group of the first to fifth embodiments.

  (2) Although the supercooling heat exchanger 203 is used in the first embodiment, a gas-liquid separator can be used instead.

  (3) In any of the first to fifth embodiments, the hot gas bypass circuit 70 is provided, but the hot gas bypass circuit 70 can be omitted when it is not necessary to rapidly change the brine temperature.

  (4) In the above embodiment, based on the refrigerant gas pressure detected by the low pressure sensor 403 and the intermediate pressure sensor 405, the calculation unit 520 calculates a saturation temperature corresponding to the pressure. Instead of the low pressure sensor 403 and the intermediate pressure sensor 405, temperature sensors are provided between the evaporator expansion valve 103 and the evaporator 104, and between the economizer control valve 202 and the supercooling heat exchange economizer 203, respectively. Thus, the temperature detected by the temperature sensor may be the saturation temperature.

  (5) Instead of the suction side injection pipe opening / closing mechanism 204 of the second and fifth embodiments, a three-way valve can be provided at the branch portion 301 where the intermediate injection pipe 30 branches from the suction side injection pipe 20.

1 is a schematic diagram illustrating a refrigeration apparatus according to Embodiment 1. FIG. It is a figure for demonstrating the function of a hot gas bypass circuit, (A) is a schematic diagram which shows an example of the temperature control of the refrigerant | coolant of the structure which remove | excluded the hot gas bypass circuit from the refrigeration apparatus which concerns on Embodiment 1, and a brine. (B) is a schematic diagram which shows an example of the temperature control of the refrigerant | coolant and brine of a refrigerating device which concern on Embodiment 1 provided with a hot gas bypass circuit. FIG. 3 is a Mollier diagram showing the refrigeration cycle in the example of FIG. 2 when the suction side injection pipe opening / closing mechanism is in an open state, (A) corresponds to the example of FIG. 2 (A), and (B) is This corresponds to the example of FIG. It is a block diagram which shows the functional structure of the controller with which the refrigeration apparatus which concerns on Embodiment 1 is provided. 3 is a flowchart for explaining temperature control and superheat degree control of a compressor suction unit in the refrigeration apparatus according to Embodiment 1. It is a schematic diagram which shows the freezing apparatus which concerns on Embodiment 2 of this invention. It is a block diagram which shows the functional structure of the controller with which the refrigeration apparatus which concerns on Embodiment 2 is provided. It is a figure which shows the relationship between the opening / closing control of the suction side injection piping opening / closing mechanism by an opening / closing mechanism control part, and the opening degree control of the economizer control valve by an economizer control valve control part. 6 is a flowchart for explaining temperature control and superheat degree control of a compressor suction portion and superheat degree control of an intermediate injection portion in a refrigeration apparatus according to Embodiment 2. It is a schematic diagram which shows the freezing apparatus which concerns on Embodiment 3. 6 is a Mollier diagram showing a refrigeration cycle in a refrigeration apparatus according to Embodiment 3. FIG. It is a block diagram which shows the functional structure of the controller with which the refrigeration apparatus which concerns on Embodiment 3 is provided. 10 is a flowchart for explaining temperature control of a compressor suction portion in a refrigeration apparatus according to Embodiment 3. It is a schematic diagram which shows the freezing apparatus which concerns on Embodiment 4. It is a block diagram which shows the functional structure of the controller with which the refrigeration apparatus which concerns on Embodiment 4 is provided. 10 is a flowchart for explaining temperature control of a compressor suction unit and superheat control of an intermediate injection unit in a refrigeration apparatus according to Embodiment 4. FIG. 10 is a schematic diagram showing a refrigeration apparatus according to Embodiment 5. It is a block diagram which shows the functional structure of the controller with which the refrigeration apparatus which concerns on Embodiment 5 is provided. 10 is a flowchart for explaining temperature control of a compressor suction portion and superheat degree control of an intermediate injection portion in a refrigeration apparatus according to Embodiment 5. It is a schematic diagram which shows the example of the freezing apparatus which substituted the supercooling heat exchange economizer in Embodiment 2 with the gas-liquid separation economizer. FIG. 21 is a Mollier diagram corresponding to the refrigeration apparatus of FIG. 20. It is a schematic diagram which shows the example of the freezing apparatus which substituted the supercooling heat exchange economizer in Embodiment 3 with the gas-liquid separation economizer. It is a Mollier diagram corresponding to the freezing apparatus of FIG. It is a schematic diagram which shows the conventional refrigeration apparatus of a liquid injection system. FIG. 25 is a Mollier diagram showing a refrigeration cycle in the conventional liquid injection type refrigeration apparatus shown in FIG. 24.

Explanation of symbols

1-8, 1 'Refrigeration apparatus 10 Refrigerant circuit 101 Compressor 102 Condenser 103 Evaporator expansion valve 104 Evaporator 20-26 Suction side injection piping 201 Branching portion 202 Supercooling heat exchanger control valve (flow rate adjusting mechanism)
203 Supercooling heat exchanger 203 'Gas-liquid separation economizer (gas-liquid separator)
204 Suction side injection pipe opening / closing mechanism 205 Suction side injection control valve 206 Capillary tube 209 Suction side connection part 30 Intermediate injection pipe 301 Branch part 309 Intermediate injection part 40-43 Sensor group 401 Low temperature temperature sensor before suction (first temperature detection part)
402 Low temperature sensor before injection (second temperature detector)
403 Low pressure sensor (low pressure detector)
404 Intermediate injection unit temperature sensor (intermediate injection unit temperature detection unit)
405 Intermediate pressure sensor (intermediate injection pressure detector)
50-54 controller (control unit)
510 system control unit 520 calculation unit 511 refrigerant circuit control unit 512 brine circuit control unit 513 hot gas bypass circuit control unit 514 supercooling heat exchanger control valve control unit 515 opening / closing mechanism control unit 516 suction side injection control valve control unit 60 brine circuit 70 Hot gas bypass circuit 701 Branch

Claims (21)

A refrigerant circuit (10) in which a mainstream refrigerant circulates in a circuit in which a compressor (101), a condenser (102), an evaporator expansion valve (103), and an evaporator (104) are connected by refrigerant piping;
A suction side which is a connection provided in a suction side pipe of the compressor (101) from a branch (201) between the condenser (102) and the evaporator expansion valve (103) of the refrigerant circuit (10) Refrigerant piping connected to the connecting portion (209), wherein a branched refrigerant that is branched from the mainstream refrigerant at the branching portion (201) is injected into the suction side connecting portion (209). A suction side injection pipe (20),
A diverted refrigerant gasification mechanism (203) for gasifying the diverted refrigerant;
A flow rate adjusting mechanism (202) for adjusting the flow rate of the divided refrigerant in the suction side injection pipe (20);
A suction side temperature detector (401) provided in a pipe on the suction side of the compressor (101) of the refrigerant circuit (10) for detecting the temperature of the mainstream refrigerant passing through the pipe;
A refrigeration apparatus comprising: a control unit (50) that controls the flow rate adjustment mechanism (202) based on the temperature detected by the suction side temperature detection unit (401).   The refrigerating apparatus according to claim 1, wherein the flow rate adjusting mechanism (202) is an expansion valve (202) whose opening degree can be adjusted.   The diverted refrigerant gasification mechanism is provided at a position between the condenser (102) and the evaporator expansion valve (103) in the refrigerant circuit (10) and in the middle of the suction side injection pipe (20). The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is a supercooling heat exchanger (203) that exchanges heat between the split refrigerant and the main refrigerant.   The diverted refrigerant gasification mechanism is provided between the condenser (102) and the evaporator expansion valve (103) in the refrigerant circuit (10) and at a position that becomes the branch portion, and the diverted refrigerant gasification mechanism A gas-liquid separation / expansion valve (202) provided inside or upstream of the gas-liquid separation / expansion valve (202) is separated and only the main-phase refrigerant liquid-phase refrigerant is separated and sent to the evaporator expansion valve (103). The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is a liquid separator (203 ′). The refrigerant circuit (10) further includes an economizer (203, 203 ′) for improving COP between the condenser (102) and the evaporator expansion valve (103) of the refrigerant circuit (10). 10)
The economizer (203, 203 ′) is further located in the middle of the suction side injection pipe (20) or at the branch portion,
The shunt refrigerant gasification mechanism is the economizer (203, 203 ′),
The flow rate adjusting mechanism is an economizer control valve (202) that is an expansion valve capable of adjusting an opening to adjust a flow rate of refrigerant flowing into the economizer (203, 203 ′).
A refrigerant pipe branched from the suction side injection pipe (21, 25, 26) and connected to an intermediate injection section (309) which is a connection section provided in the middle of the compression mechanism of the compressor (101). An intermediate injection pipe (30) which is a refrigerant pipe into which the gas-phase refrigerant discharged from the gas-phase refrigerant discharge section of the economizer (203, 203 ′) is injected into the intermediate injection section (309);
Second flow rate adjusting mechanism provided in the refrigerant pipe between the branch part (301) where the intermediate injection pipe (30) branches in the suction side injection pipe (21 to 26) and the suction side connection part (209) (204-206),
The control unit (51-54) is configured to switch between the economizer control valve (202) and the second flow rate adjustment mechanism (204-206) according to the temperature detected by the suction side temperature detection unit (402). The refrigeration apparatus according to claim 1, wherein at least one of the refrigeration apparatuses is controlled.   The refrigerating apparatus according to claim 5, wherein the second flow rate adjusting mechanism is a suction side injection pipe opening / closing mechanism (204) which is a flow path opening / closing mechanism.   The refrigeration apparatus according to claim 5, wherein the second flow rate adjusting mechanism is a suction side injection control valve (205) that is an expansion valve capable of adjusting an opening degree.   The refrigeration apparatus according to claim 5, wherein the second flow rate adjusting mechanism is a capillary tube (206).   The refrigeration apparatus according to claim 5, wherein the second flow rate adjustment mechanism includes a capillary tube (206) and a suction-side injection pipe opening / closing mechanism (204) that is a flow path opening / closing mechanism. The suction side temperature detection part (401) is provided between the suction part (109) of the compressor (101) and the suction side connection part (209),
A low pressure detection unit (403) provided in a pipe between the suction part (109) of the compressor (101) and the suction side connection part (209) and detecting the pressure of the refrigerant in the pipe is further provided. ,
The control unit (50)
When the temperature detected by the suction side temperature detection unit (401) is equal to or higher than a predetermined threshold, the flow rate adjustment mechanism (202) is controlled to increase the flow rate of the divided refrigerant,
When the temperature detected by the temperature detection unit (401) is smaller than the threshold value, the suction using the temperature detected by the temperature detection unit (401) and the pressure detected by the low pressure detection unit (403) The refrigerating apparatus according to any one of claims 1 to 4, wherein the degree of superheat of the section (109) is calculated, and the flow rate adjusting mechanism (202) is controlled so that the degree of superheat falls within a predetermined range. The suction side temperature detection unit includes a first temperature detection unit (401) provided between the suction unit (109) and the suction side connection unit (209) of the compressor (101), and the suction side connection. Part (209) and the second temperature detection part (402) provided between the evaporator (104),
A low-pressure detector (403) provided in a pipe between the suction part (109) of the compressor (101) and the suction-side connection part (209) for detecting the pressure of the refrigerant in the pipe;
An intermediate injection unit temperature detection unit (404) provided in the intermediate injection unit (309) and detecting a refrigerant temperature of the intermediate injection unit (309);
An intermediate injection part pressure detector (405) that is provided in the intermediate injection part (309) and detects a refrigerant pressure of the intermediate injection part (309);
The control unit (51)
When the temperature detected by the second temperature detection unit (402) is equal to or higher than a predetermined first threshold, the inhalation is performed until the temperature becomes lower than a predetermined second threshold smaller than the first threshold. The side injection pipe opening / closing mechanism (204) is opened, and the suction unit (109) is configured to use the temperature detected by the first temperature detection unit (401) and the pressure detected by the low pressure detection unit (403). Calculating the degree of superheat and performing suction part superheat degree control for controlling the opening degree of the economizer control valve (202) so that the degree of superheat of the suction part (109) is within a predetermined range;
When the temperature detected by the second temperature detection unit (402) is lower than the second threshold, the suction side injection pipe opening / closing mechanism (204) is closed until the temperature becomes equal to or higher than the first threshold. And the degree of superheat of the intermediate injection unit (309) is calculated using the temperature detected by the intermediate injection unit temperature detection unit (404) and the pressure detected by the intermediate injection unit pressure detection unit (405). Performing intermediate injection unit superheat control to control the opening of the economizer control valve (202) so that the superheat of the intermediate injection unit (309) is within a predetermined range;
When the temperature detected by the second temperature detection unit (402) is equal to or higher than the second threshold value and lower than the first threshold value, when the suction side injection pipe opening / closing mechanism (204) is in the open state, the suction unit The refrigerating apparatus according to claim 6, wherein superheat degree control is performed, and when the suction side injection pipe opening / closing mechanism (204) is in a closed state, the intermediate injection section superheat degree control is performed. The suction side temperature detection part (401) is provided between the suction part (109) of the compressor (101) and the suction side connection part (209),
The control unit (52)
When the temperature detected by the suction side temperature detection unit (401) is equal to or higher than a predetermined threshold, the opening degree of the suction side injection control valve (205) is increased until the temperature becomes lower than the threshold.
When the temperature detected by the suction side temperature detection unit (401) is less than the threshold value, the opening degree of the suction side injection control valve (205) is decreased until the temperature becomes equal to or higher than the threshold value. The refrigeration apparatus described in 1. The suction side temperature detection part (401) is provided between the suction part (109) of the compressor (101) and the suction side connection part (209),
An intermediate injection unit temperature detection unit (404) provided in the intermediate injection unit (309) and detecting a refrigerant temperature of the intermediate injection unit (309);
An intermediate injection part pressure detector (405) that is provided in the intermediate injection part (309) and detects a refrigerant pressure of the intermediate injection part (309);
The control unit (53)
When the temperature detected by the suction side temperature detection unit (401) is equal to or higher than a predetermined threshold, the opening degree of the economizer control valve is increased until the temperature becomes lower than the first threshold,
When the temperature detected by the suction side temperature detection unit (401) is less than the threshold, the temperature detected by the intermediate injection unit temperature detection unit (404) and the pressure detected by the intermediate injection unit pressure detection unit (405) And the degree of superheat of the intermediate injection section (309) is calculated, and the opening degree of the economizer control valve (202) is controlled so that the degree of superheat of the intermediate injection section (309) falls within a predetermined range. The refrigeration apparatus according to claim 8. The suction side temperature detection unit includes a first temperature detection unit (401) provided between the suction unit (109) and the suction side connection unit (209) of the compressor (101), and the suction side connection. Part (209) and the second temperature detection part (402) provided between the evaporator (104),
An intermediate injection unit temperature detection unit (404) provided in the intermediate injection unit (309) and detecting a refrigerant temperature of the intermediate injection unit (309);
An intermediate injection part pressure detector (405) that is provided in the intermediate injection part (309) and detects a refrigerant pressure of the intermediate injection part (309);
The control unit (54)
When the temperature detected by the second temperature detection unit (402) is equal to or higher than a predetermined first threshold, the inhalation is performed until the temperature becomes lower than a predetermined second threshold smaller than the first threshold. A side injection pipe opening / closing mechanism (204) is opened, and a suction part temperature control is performed to control the opening of the economizer control valve (202) using the temperature detected by the first temperature detection part (401);
When the temperature detected by the suction side temperature detection unit (402) is less than the second threshold, the suction side injection pipe opening / closing mechanism (204) is closed until the temperature becomes equal to or higher than the first threshold. And the degree of superheat of the intermediate injection unit (309) is calculated using the temperature detected by the intermediate injection unit temperature detection unit (404) and the pressure detected by the intermediate injection unit pressure detection unit (405). Performing intermediate injection unit superheat control to control the opening of the economizer control valve (202) so that the superheat of the intermediate injection unit (309) is within a predetermined range;
When the temperature detected by the suction side temperature detection unit (402) is equal to or higher than the second threshold value and lower than the first threshold value, when the suction side injection pipe opening / closing mechanism (204) is in the open state, the suction unit The refrigeration apparatus according to claim 9, wherein temperature control is performed, and when the suction side injection pipe opening / closing mechanism (204) is in a closed state, the intermediate injection section superheat degree control is performed.   The economizer is provided between the condenser (102) and the evaporator expansion valve (103) in the refrigerant circuit (10) and at a position in the middle of the suction side injection pipe (24). The refrigerating apparatus according to any one of claims 5 to 14, which is a supercooling heat exchanger (203) for exchanging heat between the refrigerant and the mainstream refrigerant.   The economizer is provided between the condenser (102) and the evaporator expansion valve (103) in the refrigerant circuit (10) and at a position that becomes the branch portion, and the inside of the diverted refrigerant gasification mechanism or its A gas-liquid separator that has a gas-liquid separation expansion valve (202) upstream and separates only the liquid refrigerant of the mainstream refrigerant that has passed through the gas-liquid separation expansion valve (202) and sends it to the evaporator expansion valve (103). The refrigeration apparatus according to any one of claims 5, 6, 8, and 9, which is (203 '). The suction side temperature detection part (401) is provided between the suction part (109) of the compressor (101) and the suction side connection part (209),
The control unit (51, 53, 54)
When the temperature detected by the suction side temperature detection unit (401) is equal to or higher than a predetermined threshold, the opening of the economizer control valve (202) is increased until the temperature becomes lower than the threshold,
The opening degree of the economizer control valve (202) is decreased when the temperature detected by the suction side temperature detection unit (401) is lower than the threshold value until the temperature becomes equal to or higher than the threshold value. The refrigeration apparatus described.   The economizer is provided between the condenser (102) and the evaporator expansion valve (103) in the refrigerant circuit (10) and at a position that becomes the branch portion, and the inside of the diverted refrigerant gasification mechanism or its A gas-liquid separator that has a gas-liquid separation expansion valve (202) upstream and separates only the liquid refrigerant of the mainstream refrigerant that has passed through the gas-liquid separation expansion valve (202) and sends it to the evaporator expansion valve (103). The refrigeration apparatus according to claim 7, which is (203 ′). The suction side temperature detection part (401) is provided between the suction part (109) of the compressor (101) and the suction side connection part (209),
The control unit (52)
When the temperature detected by the suction side temperature detection unit (401) is equal to or higher than a predetermined threshold, the opening degree of the suction side injection control valve (205) is increased until the temperature becomes lower than the threshold.
19. When the temperature detected by the suction side temperature detection unit (401) is lower than the threshold value, the opening degree of the suction side injection control valve (205) is decreased until the temperature becomes equal to or higher than the threshold value. The refrigeration apparatus described in 1.   A circuit provided separately from the refrigerant circuit (10), wherein the brine in the circuit and the mainstream refrigerant in the refrigerant circuit (10) are heat-exchanged by the evaporator (104). The refrigeration apparatus according to any one of claims 1 to 19, further comprising a brine circuit (60) for cooling the water.   Branched from a branch part (701) provided in a refrigerant pipe between the compressor (101) and the condenser (102), the suction side connection part (209) and the suction side temperature detection part (402) The refrigeration apparatus according to any one of claims 1 to 20, further comprising a hot gas bypass circuit (70) that is a circuit connected to a refrigerant pipe between the upstream side and the evaporator (104).

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