JP2022027894A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a refrigerator capable of accurately determining a refrigerant amount.

SOLUTION: In a refrigerator, a heat source side unit that has a heat source side heat exchanger and a supercooler functioning as a compressor and a condenser, and at least one use side unit that has a use side expansion valve and a use side heat exchanger functioning as an evaporator, are connected by piping, and a refrigerant circuit is provided in which a refrigerant circulates. The refrigerator includes a first temperature sensor detecting condensation temperature and a discharge pressure sensor detecting the pressure of the refrigerant discharged from the compressor, a second sensor detecting evaporation temperature and a suction pressure sensor detecting the pressure of the refrigerant sucked in the compressor, a drive unit that controls the operation frequency of the compressor so as to make the condensation temperature or the evaporation temperature constant, and a refrigerant amount determining unit that determines a refrigerant amount filled in the refrigerant circuit by using a supercooling degree of the refrigerant at an outlet of the supercooler or the temperature efficiency of the supercooler which is a value obtained by dividing the supercooling degree by the maximum temperature difference of the supercooler.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a refrigerating apparatus for determining the amount of refrigerant in a refrigerant circuit.

In a refrigerating apparatus, if an excess or deficiency of the amount of refrigerant occurs, it causes a decrease in the capacity of the refrigerating apparatus and damage to constituent equipment. Therefore, in order to prevent the occurrence of such a problem, some have a function of determining the excess or deficiency of the amount of the refrigerant filled in the refrigerating apparatus.

As a method of determining the refrigerant shortage in the conventional refrigerating device, for example, the temperature difference between the inlet refrigerant temperature and the outlet refrigerant temperature of the supercooler is calculated, and when this temperature difference decreases from the set value, it is determined that the refrigerant is leaking. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 9-105567

However, in the conventional refrigerating apparatus described in Patent Document 1, since the insufficient amount of the refrigerant is determined by utilizing the change in the degree of supercooling, an erroneous determination is likely to occur in the determination of the refrigerant leakage. This is because the degree of supercooling varies greatly depending on the operating conditions of the refrigerating apparatus.

The present invention has been made against the background of the above problems, and an object of the present invention is to obtain a freezing device capable of accurately determining the amount of refrigerant.

The refrigerating apparatus according to the present invention includes a heat source side unit having a heat source side heat exchanger and a supercooler that function as a compressor and a condenser, and a user side heat exchanger that functions as a user side expansion valve and an evaporator. A refrigerating device having at least one user-side unit connected by a pipe and having a refrigerant circuit for circulating the refrigerant, the first temperature sensor for detecting the condensation temperature of the refrigerant, or the refrigerant discharged by the compressor. It is detected by the discharge pressure sensor that detects the pressure of the compressor, the second temperature sensor that detects the evaporation temperature of the refrigerant, the suction pressure sensor that detects the pressure of the refrigerant sucked into the compressor, and the discharge pressure sensor. Obtained by saturation conversion of pressure, or obtained by saturation conversion of the condensation temperature detected by the first temperature sensor, or the pressure detected by the suction pressure sensor, or by the second temperature sensor. The overcooling degree of the refrigerant at the outlet of the overcooler and the driving unit that controls the operating frequency of the compressor so that the detected evaporation temperature becomes constant, or the overcooling degree of the overcooler. It has a refrigerant amount determination unit that determines the amount of refrigerant filled in the refrigerant circuit by using the temperature efficiency of the supercooler, which is a value divided by the maximum temperature difference.

According to the refrigerating apparatus of the present invention, the amount of the refrigerant can be accurately determined.

It is a figure which schematically describes an example of the refrigerant circuit of the refrigerating apparatus which concerns on Embodiment 1 of this invention. It is a figure which schematically describes an example of the structure of the refrigerating apparatus which concerns on Embodiment 1 of this invention. It is an example of the ph diagram when the amount of the refrigerant of the refrigerating apparatus shown in FIG. 1 is appropriate. It is an example of the ph diagram when the amount of the refrigerant of the refrigerating apparatus shown in FIG. 1 becomes insufficient. It is a figure explaining the relationship between the amount of a refrigerant of the refrigerating apparatus shown in FIG. 1, the degree of supercooling of a first supercooler, and the operating condition of a refrigerating apparatus. FIG. 1 is a diagram illustrating an example of a temperature change of the refrigerant when the refrigerant flows in the order of the heat source side heat exchanger, the receiver, and the air supercooler when the amount of the refrigerant is an appropriate amount in the refrigerating apparatus shown in FIG. Is. It is a figure explaining the relationship between the amount of a refrigerant of the refrigerating apparatus shown in FIG. 1, the temperature efficiency of the first supercooler, and the operating condition of a refrigerating apparatus. It is a figure for demonstrating that in the refrigerant amount determination of this embodiment, when a compressor is an inverter compressor, the refrigerant amount determination is not performed according to the magnitude of a low pressure pressure. It is a figure for demonstrating that in the refrigerant amount determination of this embodiment, when a compressor is a constant speed compressor, the refrigerant amount determination is not performed according to the magnitude of a low pressure pressure. It is a figure which shows an example of the relationship between the air volume of a fan on a heat source side, and a temperature efficiency threshold value. It is a figure explaining the relationship between the condensation temperature, the outside air temperature, the outlet temperature of the 1st supercooler, and the temperature efficiency before and after the start of a compressor. It is a figure explaining an example of the refrigerant amount determination operation of the refrigerating apparatus shown in FIG. It is modification 1 of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be omitted or simplified as appropriate. In addition, the shape, size, arrangement, etc. of the configuration shown in each figure can be appropriately changed within the scope of the present invention.

Embodiment 1.
[Refrigerator]
FIG. 1 is a diagram schematically showing an example of a refrigerant circuit of the refrigerating apparatus according to the first embodiment of the present invention. The refrigerating apparatus 1 shown in FIG. 1 cools a room, a warehouse, a showcase, a refrigerator, or the like by performing a steam compression type refrigerating cycle operation. The refrigerating apparatus 1 includes, for example, one heat source side unit 2 and two utilization side units 4 connected in parallel to the heat source side unit 2. By connecting the heat source side unit 2 and the utilization side unit 4 by the liquid refrigerant extension pipe 6 and the gas refrigerant extension pipe 7, the refrigerant circuit 10 for circulating the refrigerant is formed. The refrigerant filled in the refrigerant circuit 10 of this embodiment is, for example, R410A, which is an HFC-based mixed refrigerant. In the example of FIG. 1, one heat source side unit 2 and two user side units 4 are described, but the heat source side unit 2 may be two or more units, and the user side unit 4 may be used. May be 1 or 3 or more. When there are a plurality of heat source side units 2, the capacities of the plurality of heat source side units 2 may be the same or different. When there are a plurality of user-side units 4, the capacities of the plurality of user-side units 4 may be the same or different. In the following description, the refrigerating device 1 in which the refrigerant exchanges heat with air will be described, but the refrigerant may be a refrigerating device that exchanges heat with a fluid such as water, a refrigerant, or brine.

[User unit]
The user-side unit 4 is, for example, an indoor unit installed in a room, and includes a user-side refrigerant circuit 10a and a user-side control unit 32 that form a part of the refrigerant circuit 10. The user-side refrigerant circuit 10a includes a user-side expansion valve 41 and a user-side heat exchanger 42. The user-side expansion valve 41 adjusts the flow rate of the refrigerant flowing through the user-side refrigerant circuit 10a, and is composed of, for example, an electronic expansion valve or a temperature-type expansion valve. The utilization side expansion valve 41 may be arranged in the heat source side unit 2. In that case, the utilization side expansion valve 41 may be, for example, the first supercooler 22 and the liquid side of the heat source side unit 2. It is arranged between the closing valve 28 and the shutoff valve 28. The user-side heat exchanger 42 is, for example, a fin-and-tube heat exchanger configured to include a heat transfer tube and a large number of fins, and functions as an evaporator for evaporating the refrigerant.

In the vicinity of the user-side heat exchanger 42, a user-side fan 43 that blows air to the user-side heat exchanger 42 is arranged. The user-side fan 43 includes, for example, a centrifugal fan, a multi-blade fan, or the like, and is driven by a motor (not shown). The user-side fan 43 can adjust the amount of air blown to the user-side heat exchanger 42.

[Heat source side unit]
The heat source side unit 2 includes, for example, a heat source side refrigerant circuit 10b, a first injection circuit 71, a second injection circuit 73, and a heat source side control unit 31 that form a part of the refrigerant circuit 10. In the following description, an example having the first injection circuit 71 and the second injection circuit 73 will be described, but the refrigerating apparatus 1 is any one of the first injection circuit 71 and the second injection circuit 73. It may have a configuration having one of them.

The heat source side refrigerant circuit 10b includes a compressor 21, a heat source side heat exchanger 23, a receiver 25, a first supercooler 22, a liquid side closing valve 28, a gas side closing valve 29, and an accumulator 24. The first injection circuit 71 branches a part of the refrigerant sent from the heat source side heat exchanger 23 to the user side heat exchanger 42 from the heat source side refrigerant circuit 10b and returns it to the intermediate pressure portion of the compressor 21. , The injection amount adjusting valve 72 is included. The second injection circuit 73 branches a part of the refrigerant sent from the heat source side heat exchanger 23 to the user side heat exchanger 42 from the heat source side refrigerant circuit 10b and flows into the suction portion of the compressor 21. , A capillary tube 74 and a solenoid valve 75 for suction injection.

The compressor 21 is, for example, an inverter compressor controlled by an inverter, and the operating frequency can be arbitrarily changed to change the capacity (the amount of refrigerant delivered per unit time). The compressor 21 may be a constant speed compressor that operates at 50 Hz or 60 Hz. Further, although FIG. 1 shows an example of having one compressor 21, two or more compressors 21 are connected in parallel according to the size of the load of the user-side unit 4 and the like. You may.

The heat source side heat exchanger 23 is, for example, a fin & tube type heat exchanger configured to include a heat transfer tube and a large number of fins, and functions as a condenser for condensing the refrigerant. In the vicinity of the heat source side heat exchanger 23, a heat source side fan 27 that blows air to the heat source side heat exchanger 23 is arranged. The heat source side fan 27 blows the outside air sucked from the outside of the heat source side unit 2 to the heat source side heat exchanger 23. The heat source side fan 27 includes, for example, a centrifugal fan, a multi-blade fan, or the like, and is driven by a motor (not shown). The heat source side fan 27 can adjust the amount of air blown to the heat source side heat exchanger 23.

The receiver 25 is arranged between the heat source side heat exchanger 23 and the first supercooler 22 to store the surplus liquid refrigerant, for example, a container for storing the surplus liquid refrigerant. The surplus liquid refrigerant is generated in the refrigerant circuit 10 according to, for example, the size of the load of the user-side unit 4, the condensation temperature of the refrigerant, the outside air temperature, the capacity of the compressor 21, and the like.

The first supercooler 22 exchanges heat between the refrigerant and air, and is integrally formed with the heat source side heat exchanger 23. That is, in the example of this embodiment, a part of the heat exchanger is configured as the heat source side heat exchanger 23, and the other part of the heat exchanger is configured as the first supercooler 22. The first supercooler 22 corresponds to the "supercooler" of the present invention. The first supercooler 22 and the heat source side heat exchanger 23 may be configured separately. In that case, a fan (not shown) for blowing air to the first supercooler 22 is arranged in the vicinity of the first supercooler 22.

The liquid-side closing valve 28 and the gas-side closing valve 29 are composed of valves that open and close, such as a ball valve, an on-off valve, and an operating valve. The capillary tube 74 may be composed of a valve capable of adjusting the flow rate.

In the example shown in FIG. 1, the inlets of the first injection circuit 71 and the second injection circuit 73 are connected between the first supercooler 22 and the liquid side closing valve 28, but the first injection. The inlets of the circuit 71 and the second injection circuit 73 may be connected between the receiver 25 and the first supercooler 22, may be connected to the receiver 25, or may be connected to the heat source side heat exchanger 23. It may be connected to the receiver 25.

[Control unit and sensors]
Next, the control unit and the sensors included in the refrigerating apparatus 1 of this embodiment will be described. The heat source side unit 2 includes a heat source side control unit 31 that controls the entire refrigeration apparatus 1. The heat source side control unit 31 includes a microcomputer, a memory, and the like. Further, the user-side unit 4 includes a user-side control unit 32 that controls the user-side unit 4. The user-side control unit 32 includes a microcomputer, a memory, and the like. The user-side control unit 32 and the heat source-side control unit 31 can communicate with each other to exchange control signals. For example, the user-side control unit 32 receives an instruction from the heat source-side control unit 31. It receives and controls the user side unit 4.

The refrigerating apparatus 1 according to this embodiment includes a suction temperature sensor 33a, a discharge temperature sensor 33b, a suction outside air temperature sensor 33c, a supercooler high pressure side outlet temperature sensor 33d, a user side heat exchange inlet temperature sensor 33e, and a user side heat exchange. It includes an outlet temperature sensor 33f, a suction air temperature sensor 33g, a suction pressure sensor 34a, and a discharge pressure sensor 34b. The suction temperature sensor 33a, the discharge temperature sensor 33b, the suction outside air temperature sensor 33c, the supercooler high pressure side outlet temperature sensor 33d, the suction pressure sensor 34a, and the discharge pressure sensor 34b are arranged in the heat source side unit 2 and are controlled on the heat source side. It is connected to the unit 31. The user-side heat exchange inlet temperature sensor 33e, the user-side heat exchange outlet temperature sensor 33f, and the suction air temperature sensor 33g are arranged in the user-side unit 4 and connected to the user-side control unit 32.

The suction temperature sensor 33a detects the temperature of the refrigerant sucked by the compressor 21. The discharge temperature sensor 33b detects the temperature of the refrigerant discharged by the compressor 21. The supercooler high pressure side outlet temperature sensor 33d detects the temperature of the refrigerant that has passed through the first supercooler 22. The user-side heat exchange inlet temperature sensor 33e detects the evaporation temperature of the gas-liquid two-phase refrigerant flowing into the user-side heat exchanger 42. The user-side heat exchange outlet temperature sensor 33f detects the temperature of the refrigerant flowing out of the user-side heat exchanger 42. The sensor for detecting the temperature of the refrigerant is arranged, for example, in contact with the refrigerant pipe or inserted into the refrigerant pipe, and detects the temperature of the refrigerant.

The suction outside air temperature sensor 33c detects the outdoor ambient temperature by detecting the temperature of the air before passing through the heat source side heat exchanger 23. The suction air temperature sensor 33g detects the ambient temperature in the room where the user-side heat exchanger 42 is installed by detecting the temperature of the air before passing through the user-side heat exchanger 42.

The suction pressure sensor 34a is arranged on the suction side of the compressor 21 and detects the pressure of the refrigerant sucked into the compressor 21. The suction pressure sensor 34a may be disposed between the gas side closing valve 29 and the compressor 21. The discharge pressure sensor 34b is arranged on the discharge side of the compressor 21 and detects the pressure of the refrigerant discharged by the compressor 21.

In the example of this embodiment, the condensation temperature of the heat source side heat exchanger 23 is obtained by converting the pressure of the discharge pressure sensor 34b into the saturation temperature, but the condensation temperature of the heat source side heat exchanger 23 is obtained. Can also be obtained by disposing a temperature sensor on the heat source side heat exchanger 23.

FIG. 2 is a diagram schematically showing an example of the configuration of the refrigerating apparatus according to the first embodiment of the present invention. The control unit 3 controls the entire refrigerating device 1, and the control unit 3 of the example of this embodiment is included in the heat source side control unit 31. The control unit 3 corresponds to the "refrigerant amount determination unit" of the present invention. The control unit 3 includes an acquisition unit 3a, a calculation unit 3b, a storage unit 3c, and a drive unit 3d. The acquisition unit 3a, the calculation unit 3b, and the drive unit 3d are configured to include, for example, a microcomputer, and the storage unit 3c is configured to include, for example, a semiconductor memory. The acquisition unit 3a acquires information such as temperature and pressure detected by sensors such as a pressure sensor and a temperature sensor. The calculation unit 3b performs processing such as calculation, comparison, and determination using the information acquired by the acquisition unit 3a. The drive unit 3d controls the drive of the compressor 21, valves, fans, etc. by using the result calculated by the calculation unit 3b. The storage unit 3c stores the physical property values of the refrigerant (saturation pressure, saturation temperature, etc.), data for the calculation unit 3b to perform calculations, and the like. The arithmetic unit 3b can refer to or update the stored contents of the storage unit 3c as needed.

Further, the control unit 3 includes an input unit 3e and an output unit 3f. The input unit 3e inputs an operation input from a remote controller or switches (not shown), or inputs communication data from a communication means (not shown) such as a telephone line or a LAN line. The output unit 3f outputs the processing result of the control unit 3 to a display means (not shown) such as an LED or a monitor and outputs it to a notification means (not shown) such as a speaker, or a telephone line or a LAN line. It is output to a communication means (not shown) such as. When information is output to a remote location by a communication means, it is preferable to provide a communication means (not shown) having the same communication protocol in both the refrigerating device 1 and the remote device (not shown).

For example, the refrigerating device 1 and the remote device (not shown) can be used to determine whether the amount of refrigerant is insufficient or the like. In that case, for example, the calculation unit 3b calculates the temperature efficiency T of the first supercooler 22 using the information acquired by the acquisition unit 3a, and the output unit 3f calculates the temperature efficiency calculated by the calculation unit 3b. T is transmitted to the remote device. The remote device includes a refrigerant shortage determination means (not shown) for determining a refrigerant shortage amount, and determines the refrigerant shortage amount using the temperature efficiency T. By managing the refrigerant shortage information and the like with the remote device, it is possible to detect an abnormality of the refrigerating device 1 at an early stage at the place where the remote device is installed, so that when an abnormality occurs in the refrigerating device 1, etc. , Maintenance of the freezing device 1 can be performed at an early stage.

In the above description, the example in which the control unit 3 is included in the heat source side control unit 31 has been described, but the control unit 3 may be included in the user side control unit 32, or the heat source. The side control unit 31 and the user side control unit 32 may be configured separately.

[Operation of refrigerating device (when the amount of refrigerant is appropriate)]
FIG. 3 is an example of a ph diagram of the refrigerating apparatus shown in FIG. 1 when the amount of refrigerant is appropriate. First, the operation of the refrigerating apparatus 1 when the amount of the refrigerant is appropriate will be described. From point K to point L in FIG. 3, the compressor 21 shown in FIG. 1 compresses the refrigerant. From point L to point M in FIG. 3, the high-temperature and high-pressure gas refrigerant compressed by the compressor 21 of FIG. 1 is heat-exchanged by the heat source-side heat exchanger 23 functioning as a condenser to be condensed and liquefied. The refrigerant that has been heat-exchanged by the heat source side heat exchanger 23 and is condensed and liquefied flows into the receiver 25 and is temporarily stored in the receiver 25. The amount of the refrigerant stored in the receiver 25 changes depending on the operating load of the user-side unit 4, the outside air temperature, the condensation temperature, and the like.

From point M to point N in FIG. 3, the liquid refrigerant stored in the receiver 25 in FIG. 1 is supercooled by the first supercooler 22. The degree of supercooling at the outlet of the first supercooler 22 is calculated by subtracting the temperature of the supercooler high-pressure side outlet temperature sensor 33d from the condensation temperature.

From point N to point O in FIG. 3, the liquid refrigerant supercooled by the first supercooler 22 in FIG. 1 passes through the liquid side closing valve 28 and the liquid refrigerant extension pipe 6 to the user side unit 4. It is sent and decompressed by the expansion valve 41 on the utilization side to become a low-pressure gas-liquid two-phase refrigerant.

From point O to point K in FIG. 3, the gas-liquid two-phase refrigerant decompressed by the utilization-side expansion valve 41 in FIG. 1 is gasified by the utilization-side heat exchanger 42 that functions as an evaporator. The degree of overheating of the refrigerant is calculated by subtracting the evaporation temperature of the refrigerant detected by the user-side heat exchange inlet temperature sensor 33e from the temperature detected by the user-side heat exchange outlet temperature sensor 33f. The gas refrigerant gasified by the user-side heat exchanger 42 returns to the compressor 21 via the gas-refrigerant extension pipe 7, the gas-side closing valve 29, and the accumulator 24.

Next, the injection circuit will be described. The first injection circuit 71 is for lowering the refrigerant temperature of the discharge portion of the compressor 21. The inlet of the first injection circuit 71 is connected between the outlet of the first supercooler 22 and the liquid side closing valve 28, and a part of the high-pressure liquid refrigerant supercooled by the first supercooler 22 is The pressure is reduced by the injection amount adjusting valve 72 to become an intermediate pressure two-phase refrigerant, which flows into the injection portion of the compressor 21.

The second injection circuit 73 is for lowering the refrigerating machine oil inside the compressor 21, the temperature of the motor, and the temperature of the refrigerant in the discharge portion. The inlet of the second injection circuit 73 is connected between the outlet of the first supercooler 22 and the liquid side closing valve 28, and a part of the high-pressure liquid refrigerant supercooled by the first supercooler 22 is , The pressure is reduced by the capillary tube 74 to become a low-pressure two-phase refrigerant, which flows into the suction portion of the compressor 21.

[Operation of refrigeration equipment (when the amount of refrigerant is insufficient)]
FIG. 4 is an example of a ph diagram of the refrigerating apparatus shown in FIG. 1 when the amount of refrigerant is insufficient. For example, when the amount of the refrigerant decreases due to leakage of the refrigerant from the refrigerating apparatus 1 shown in FIG. 1, the excess liquid refrigerant stored in the receiver 25 decreases while the excess liquid refrigerant is stored in the receiver 25. do. As long as the excess liquid refrigerant is present in the receiver 25, the refrigerating device 1 operates in the same manner as when the amount of the refrigerant is appropriate, as shown in FIG.

When the amount of the refrigerant is further reduced and the excess liquid refrigerant in the receiver 25 is exhausted, the enthalpy at the outlet of the heat source side heat exchanger 23 functioning as a condenser becomes large as shown by the point M1 in FIG. 4, and the heat source side The refrigerant state at the outlet of the heat exchanger 23 becomes a two-phase state. Further, as the enthalpy at the outlet of the heat source side heat exchanger 23 increases, the first supercooler 22 performs condensed liquefaction and supercooling of the two-phase refrigerant, as shown at point N1. , The enthalpy at the outlet of the first supercooler 22 also increases.

[Comparative Example 1]
In Comparative Example 1, the amount of the refrigerant is determined by using the degree of supercooling of the refrigerant. For example, when the amount of the refrigerant is insufficient due to leakage of the refrigerant or the like, the degree of supercooling decreases as shown in FIG. Therefore, in Comparative Example 1, when the degree of supercooling becomes smaller than the preset threshold value, it is determined that the amount of the refrigerant is insufficient.

FIG. 5 is a diagram illustrating the relationship between the amount of refrigerant in the refrigerating apparatus shown in FIG. 1, the degree of supercooling of the first supercooler, and the operating conditions of the refrigerating apparatus. As shown in FIG. 5, the degree of supercooling of the first supercooler 22 varies greatly depending on the operating conditions of the refrigerating device 1 (outside air temperature, heat exchange amount, refrigerant circulation amount, etc.). Therefore, when determining the insufficient amount of the refrigerant by using the degree of supercooling as in Comparative Example 1, it is necessary to set the supercooling degree threshold value S low so as not to make an erroneous determination. In the first modification, since the supercooling degree threshold value S must be set low, it takes a long time to determine the shortage of the refrigerant amount. For example, when the refrigerant leaks, the amount of the refrigerant leaked is large. turn into.

[Determining the amount of refrigerant]
Therefore, in this embodiment, the amount of the refrigerant is determined by using the temperature efficiency T of the first supercooler 22 whose fluctuation with respect to the change in the operating conditions of the refrigerating apparatus 1 is smaller than that of the degree of supercooling. This will be described below.

FIG. 6 shows an example of a temperature change of the refrigerant when the refrigerant flows in the order of the heat source side heat exchanger, the receiver, and the air supercooler when the amount of the refrigerant is an appropriate amount in the refrigerating apparatus shown in FIG. It is a figure explaining. In FIG. 6, the vertical axis indicates the temperature, and the upper part is higher. Further, the horizontal axis shows the refrigerant paths of the heat source side heat exchanger 23, the receiver 25, and the first supercooler 22. s1 is the condensation temperature of the refrigerant, s2 is the refrigerant temperature at the outlet of the first supercooler 22, and s3 is the outside air temperature.

The temperature efficiency T of the first supercooler 22 indicates the efficiency of the first supercooler 22, and the maximum possible temperature difference A is taken as the denominator and the actual temperature difference B is taken as the numerator. .. In the first supercooler 22, the maximum possible temperature difference A is the difference between the condensation temperature s1 and the outside air temperature s3, and the actually possible temperature difference B is the condensation temperature s1 and the outlet of the first supercooler 22. It is the difference from the temperature s2 of. The temperature efficiency T is expressed by the following (formula 1).
Temperature efficiency T = Actually possible temperature difference B / Maximum possible temperature difference A ... (Formula 1)

FIG. 7 is a diagram illustrating the relationship between the amount of refrigerant in the refrigerating apparatus shown in FIG. 1, the temperature efficiency of the first supercooler, and the operating conditions of the refrigerating apparatus. In FIG. 7, the horizontal axis is the amount of refrigerant of the refrigerant, and the vertical axis is the temperature efficiency T of the first supercooler 22. As shown in FIG. 7, when the amount of the refrigerant becomes small, the amount of the refrigerant becomes E, and the surplus liquid refrigerant of the receiver 25 disappears, the temperature efficiency T of the first supercooler 22 decreases. Therefore, when the temperature efficiency T becomes smaller than the preset temperature efficiency threshold value T1, it is determined that the refrigerant has leaked. The temperature efficiency T indicates the performance of the supercooled heat exchanger 5, and since the fluctuation due to the operating conditions of the refrigerating apparatus 1 is smaller than the degree of supercooling, a threshold value is set for each operating condition of the refrigerating apparatus 1. It is possible to improve the determination accuracy of the insufficient amount of refrigerant.

[Exceptional conditions for determining the amount of refrigerant]
Even when the amount of refrigerant is appropriate, the determination of the amount of refrigerant using the temperature efficiency T of the first supercooler 22 may be an erroneous determination depending on the operating state of the refrigerating apparatus 1 shown in FIG. Therefore, it may be determined that the amount of refrigerant is insufficient. If it is determined that the amount of the refrigerant is insufficient when the amount of the refrigerant is an appropriate amount, it will cause confusion. Although the amount of the refrigerant is an appropriate amount, when it is determined that the amount of the refrigerant is insufficient, the determination result of the amount of the refrigerant may be determined as the appropriate amount by replenishing the refrigerant. However, in that case, the refrigerating apparatus 1 is filled with an unnecessary amount of the refrigerant, which increases the cost of the refrigerating apparatus 1. Further, if the amount of the refrigerant becomes unnecessarily large, if the refrigerant leaks, the amount of leakage until the refrigerant shortage can be determined by the refrigerant amount determination using the temperature efficiency T will be increased. Further, when the amount of the refrigerant is unnecessarily increased, the amount of the liquid back increases when the liquid back occurs, which may lead to a malfunction of the compressor 21. Therefore, in the example of this embodiment, an exception condition for determining the amount of refrigerant is provided, and when the exception condition for which the determination of the amount of refrigerant may be erroneous is satisfied, the temperature efficiency T of the first supercooler 22 is set. The amount of refrigerant used is not determined. This will be described below.

[Exception condition 1 (during user side fan delay control)]
Exception condition 1 is a case where the user side fan delay control is performed. The user-side fan delay control is performed to prevent the warm air generated during the defrosting operation from being blown out to the cooling space. After the defrosting operation is completed, the time until the temperature of the user-side heat exchanger 42 drops is, for example, several minutes, and the user-side fan 43 operates before the temperature of the user-side heat exchanger 42 drops. Then, since warm air is blown into the cooling space, the operation of the user-side fan 43 is stopped until the temperature of the user-side heat exchanger 42 drops. Then, after the temperature of the user-side heat exchanger 42 drops, the operation of the user-side fan 43 is restarted.

When the operation of the user-side fan 43 is stopped, heat exchange in the user-side heat exchanger 42 is suppressed, so that the refrigerant that has passed through the user-side heat exchanger 42 is in a gas-liquid two-phase state. There is. That is, the refrigerant that normally flows from the user-side heat exchanger 42 to the compressor 21 in a gas state flows in a two-phase state when the user-side fan delay control is performed, and the liquid refrigerant is stored in the accumulator 24. Therefore, when the fan delay control on the user side is performed, the amount of the refrigerant on the low pressure side temporarily increases, and the amount of the refrigerant on the high pressure side temporarily decreases. As a result, when the user side fan delay control is performed, the refrigerant amount determination using the temperature efficiency T may be erroneous determination. Therefore, during the fan delay control on the user side, the refrigerant amount determination using the temperature efficiency T is not performed. When the user side fan delay control is completed and the user side fan 43 is operated, the refrigerant flowing from the user side heat exchanger 42 to the compressor 21 becomes a gas state, and the shortage of the refrigerant on the high pressure side is solved.

For example, the control unit 3 determines that the refrigerating device 1 is implementing the user-side fan delay control by acquiring the operating state of the refrigerating device 1. Then, in the control unit 3, the refrigerant flowing from the user-side heat exchanger 42 to the compressor 21 during the user-side fan delay control, the user-side fan delay control, and the user-side fan delay control is in a gas state. The refrigerant shortage is not determined for a certain period of time until it becomes. Even when the user side fan delay control is not performed, when the operation of the user side fan 43 is stopped, the refrigerant amount determination using the temperature efficiency T may be an erroneous determination as described above. There is. Therefore, when the operation of the user-side fan 43 is stopped, the refrigerant amount determination using the temperature efficiency T may not be performed.

When the temperature efficiency T exceeds the preset set time and falls below the temperature efficiency threshold value T1, it can be determined that the refrigerant is insufficient. That is, the maximum time for the user-side fan delay control is, for example, about 10 minutes, and the maximum time for the refrigerant flowing from the user-side heat exchanger 42 to the compressor 21 to be in a gas state after the user-side fan delay control is performed. Is, for example, about 10 minutes. Therefore, for example, the temperature efficiency T is "the maximum time of the user-side fan delay control + the maximum time until the refrigerant flowing from the user-side heat exchanger 42 to the compressor 21 becomes a gas state after the user-side fan delay control is performed. If the set time (for example, 20 minutes) determined by "time" is exceeded and the temperature efficiency threshold is lower than T1, it can be determined that the refrigerant is insufficient.

[Exception condition 2 (when pulling down, when the evaporation temperature is high)]
The exception condition 2 is a case where the evaporation temperature is high at the time of pulling down. Normally, when the temperature inside the refrigerator is high at the time of cooling after the refrigerating apparatus 1 is stopped for a long period of time, the refrigerant circuit 10 may be operated in a state where the pressure on the low pressure side is higher than usual for a short time. In this case, the pressure from the expansion valve 41 on the user side to the suction portion of the compressor 21 becomes high, and the refrigerant density becomes high. Since the required amount of refrigerant is expressed by density × volume, the amount of refrigerant required on the low pressure side temporarily increases, and the high pressure side such as the receiver 25, the first supercooler 22, and the heat source side heat exchanger 23 temporarily increases. There is a shortage of refrigerant. Therefore, when the evaporation temperature is high at the time of pulling down, the amount of the refrigerant is not determined using the temperature efficiency T.

FIG. 8 is a diagram for explaining that in the refrigerant amount determination of this embodiment, when the compressor is an inverter compressor, the refrigerant amount determination is not performed according to the magnitude of the low pressure pressure. FIG. 9 is a diagram for explaining that in the refrigerant amount determination of this embodiment, when the compressor is a constant speed compressor, the refrigerant amount determination is not performed according to the magnitude of the low pressure pressure. .. As shown in FIG. 8, when the compressor 21 is an inverter compressor, the operating frequency of the compressor 21 may be increased so that the actual low voltage approaches the preset target low voltage P1. I'm lowering it. Further, as shown in FIG. 9, when the compressor 21 is a constant speed compressor, a low pressure cut ON value P4 for operating the compressor 21 when the low pressure rises is set, and when the low pressure drops, the low pressure cut ON value P4 is set. The low-voltage cut OFF value P3 for stopping the compressor 21 is set, and the compressor 21 is operated. That is, the low pressure during operation of the compressor 21 is operated at a substantially target low pressure when the compressor 21 is an inverter compressor, and is compressed when the compressor 21 is a constant speed compressor. Most of the operations are performed below the low pressure cut ON value for operating the machine 21. Therefore, if the current low voltage is higher than the target low voltage or the value obtained by adding the margin to the low voltage cut ON value as described below, the refrigerant shortage is not determined. That is, as shown in FIG. 8, when the compressor 21 is an inverter compressor, the refrigerant shortage is not determined when the current low pressure is larger than the target low pressure P1 + the pressure P2 of the margin α. Further, as shown in FIG. 9, when the compressor 21 is a constant speed compressor, the refrigerant shortage is determined when the current low pressure is larger than the low pressure cut ON value P4 + the pressure P5 of the margin β. do not have.

[Exception condition 3 (when the solenoid valve for suction injection is open)]
The exception condition 3 is the case where the suction injection solenoid valve 75 shown in FIG. 1 is open. When the suction injection solenoid valve 75 is opened, a part of the high-pressure liquid refrigerant is depressurized by the capillary tube 74 and flows into the suction portion of the compressor 21. At this time, normally, the gas-state low-pressure side suction injection solenoid valve 75 to the compressor 21 suction portion is in a gas-liquid two-phase state, and the amount of refrigerant temporarily increases on the low-pressure side. The high-pressure side of the first supercooler 22, the heat source side heat exchanger 23, and the like is in a state of insufficient refrigerant. It should be noted that the case where the suction injection solenoid valve 75 is opened is a rare situation because the suction gas temperature of the compressor 21 rises abnormally at the time of pulling down after a long-term stop.

Therefore, when the compressor 21 is in operation and the suction injection solenoid valve 75 is open, and for a certain period of time after the suction injection solenoid valve 75 is opened to closed, the suction injection solenoid valve 75 is used. Up to the suction part of the compressor 21 is in a gas-liquid two-phase state, the amount of refrigerant temporarily increases on the low pressure side, and the high pressure side such as the receiver 25, the first supercooler 22, and the heat source side heat exchanger 23 is in a refrigerant shortage state. Therefore, the judgment of the refrigerant shortage is not performed. In the above, an example in which the determination of the refrigerant shortage is not performed when the injection in the second injection circuit 73 is performed has been described, but the refrigerant shortage is not performed when the injection in the first injection circuit 71 is performed. It may be configured not to make a determination. In that case, it may be determined whether or not the refrigerant shortage is determined by using the opening degree of the injection amount adjusting valve 72 or the like.

[Exception condition 4 (when the air volume of the fan on the heat source side drops)]
The above-mentioned exception conditions 1 to 3 have described an example in which the amount of the refrigerant is not determined when the refrigerant on the high pressure side is temporarily insufficient. The exception condition 4 is a case where the air volume of the heat source side fan 27 is reduced. When the air volume of the heat source side fan 27 is reduced, for example, if the high pressure drops too much when the outside air drops, the differential pressure of the expansion valve 41 on the utilization side becomes small and the flow rate of the refrigerant cannot be secured. This is a case where the air volume of the heat source side fan 27 is reduced in order to maintain the high pressure. Further, for example, in order to reduce the noise of the heat source side fan 27, the air volume of the heat source side fan 27 may be reduced.

As for the temperature efficiency T, since the condensation temperature increases as the air volume of the heat source side fan 27 decreases, the maximum possible temperature difference A, which is the difference between the condensation temperature and the outside air temperature, increases. At this time, the temperature difference B that can actually be taken, which is the difference between the condensation temperature and the temperature at the outlet of the first supercooler 22, is the maximum possible temperature difference A because the air volume of the heat source side fan 27 is reduced. Does not increase compared to. Therefore, if the air volume of the heat source side fan 27 is reduced, the temperature efficiency T is lowered. In particular, when the temperature is low outside air of about -15 ° C, it is necessary to turn on / off the fan 27 on the heat source side, and the maximum possible temperature difference A, which is usually about 7K to 15K, is 30K to 50K. The temperature efficiency T decreases. Therefore, if the air volume of the heat source side fan 27 is reduced, the difference between the outside air temperature and the condensation temperature is large, or the outside air temperature is lower than a certain temperature, the refrigerant shortage is not determined.

FIG. 10 is a diagram showing an example of the relationship between the air volume of the heat source side fan and the temperature efficiency threshold value. As shown in FIG. 10, by setting the temperature efficiency threshold value T2 when the air volume of the heat source side fan 27 is reduced to a smaller value than the temperature efficiency threshold value T3 when the air volume of the heat source side fan 27 is large. It is also possible to suppress the possibility of erroneous determination of the amount of the refrigerant using the temperature efficiency T.

[Exception condition 5 (compressor stopped, fixed time after compressor started)]
The exception condition 5 is a certain period of time after the compressor is stopped and the compressor is started. FIG. 11 is a diagram illustrating the relationship between the condensation temperature, the outside air temperature, the outlet temperature of the first supercooler, and the temperature efficiency before and after the start of the compressor. For example, consider a case where the compressor 21 is started after the compressor 21 is stopped for a long period of time. During the long-term shutdown of the compressor 21, the outside air temperature, the outlet temperature of the first supercooler 22, and the condensation temperature are substantially equal. In this case, if all the temperatures are equal, the temperature efficiency T = B / A = 0/0. However, in reality, due to variations in the sensors, for example, the condensation temperature is 25.0 ° C, the outside air temperature is 24.9 ° C, the outlet temperature of the first supercooler 22 is 24.8 ° C, and the temperature efficiency T = B. /A=0.2/0.1=2.0. The above example is an example, and in reality, the temperature efficiency T greatly fluctuates due to the variation of the sensor or the like during the long-term shutdown of the compressor 21. When the compressor 21 is started at the time m1, the temperature efficiency T stabilizes at a value between 0.0 and 1.0 at the time m2. The time from the time m1 to the time m2 is, for example, about 30 seconds to 1 minute.

As described above, the temperature efficiency T is unstable for a certain period of time after the compressor 21 is stopped from the time when the compressor 21 is stopped. For example, the compressor 21 is repeatedly stopped and operated in a short time. In that case, the situation where the temperature efficiency T is low continues. As a result, even if the refrigerant does not leak, there is a possibility that the refrigerant determination using the temperature efficiency T will be insufficient. Therefore, the refrigerant shortage is not determined for a certain period of time after the compressor 21 is started while the compressor 21 is stopped.

[Refrigerant amount determination operation]
FIG. 12 is a diagram illustrating an example of a refrigerant amount determination operation of the refrigerating apparatus shown in FIG. The refrigerating apparatus 1 of this embodiment determines the amount of the refrigerant by using the temperature efficiency T of the first supercooler 22. The determination of the amount of the refrigerant described below can also be applied to the refrigerant filling work when installing the refrigerating device 1 or the refrigerant filling work when performing maintenance of the refrigerating device 1. Further, the refrigerant amount determination operation may be executed when receiving an instruction from a remote device (not shown).

In step ST1 of FIG. 12, the refrigerating apparatus 1 shown in FIG. 1 is normally operated and controlled. In the normal operation control of the refrigerating apparatus 1, the heat source side control unit 31 acquires operation data such as the pressure and temperature of the refrigerant circuit 10 detected by the sensors, and uses the operation data to obtain the condensation temperature, the evaporation temperature, and the like. The control values such as the target value and deviation of are calculated, and the actuators are controlled. The operation of the actuators will be described below.

For example, the heat source side control unit 31 controls the operating frequency of the compressor 21 so that the evaporation temperature of the refrigerating cycle of the refrigerating apparatus 1 matches the target temperature (for example, 0 ° C.). The evaporation temperature of the refrigeration cycle can also be obtained by converting the pressure detected by the suction pressure sensor 34a into the saturation temperature. For example, the heat source side control unit 31 raises the operating frequency of the compressor 21 when the current evaporation temperature is higher than the target temperature, and operates the compressor 21 when the current evaporation temperature is lower than the target value. Decrease the frequency.

Further, for example, the heat source side control unit 31 blows air to the heat source side heat exchanger 23 so that the condensation temperature of the refrigeration cycle of the refrigerating apparatus 1 matches the target temperature (for example, 45 ° C.). Controls the number of rotations of. The condensation temperature of the refrigerating cycle of the refrigerating apparatus 1 can also be obtained by converting the pressure detected by the discharge pressure sensor 34b into the saturation temperature. For example, the heat source side control unit 31 increases the rotation speed of the heat source side fan 27 when the current condensation temperature is higher than the target temperature, and increases the rotation speed of the heat source side fan 27 when the current condensation temperature is lower than the target temperature. Reduce the number of revolutions.

Further, for example, the heat source side control unit 31 adjusts the opening degree of the injection amount adjusting valve 72 of the first injection circuit 71 by using the signals obtained from the sensors, or for the suction injection of the second injection circuit 73. Adjust the opening degree of the solenoid valve 75. For example, when the current discharge temperature of the compressor 21 is high, the heat source side control unit 31 opens the injection amount adjusting valve 72 or the suction injection solenoid valve 75, and the current compressor 21 has a low discharge temperature. Closes the injection amount adjusting valve 72 or the suction injection solenoid valve 75. Further, for example, the heat source side control unit 31 controls the rotation speed of the user side fan 43 that blows air to the user side unit 4.

In step ST2, the heat source side control unit 31 is, for example, the outlet temperature of the heat source side heat exchanger 23, the temperature of the outlet of the first supercooler 22, the outside air temperature detected by the suction outside air temperature sensor 33c, and the discharge pressure sensor 34b. Calculates the temperature efficiency T of the first supercooler 22 by using the pressure or the like detected by the first supercooler 22.

In step ST3, the heat source side control unit 31 acquires the operating state of the refrigerating device 1. If the operating state of the refrigerating device 1 corresponds to the above-mentioned "exception condition for determining the amount of refrigerant", the process returns to step ST1, and the operating state of the refrigerating device 1 corresponds to the above-mentioned "exception condition for determining the amount of refrigerant". If not, the process proceeds to step ST4.

In step ST4, the heat source side control unit 31 determines whether the operation control of the refrigerating apparatus 1 performed by step ST1 is stable. If the operation control of the refrigerating apparatus 1 is not stable, the process returns to step ST1, and if the operation control of the refrigerating apparatus 1 is stable, the process proceeds to step ST5.

In step ST5, the heat source side control unit 31 determines the suitability of the refrigerant amount by comparing the refrigerant amount determination parameter with the reference value thereof. Specifically, the deviation amount ΔT (= T—Tm) between the temperature efficiency T of the first supercooler 22 and the determination threshold value Tm is obtained, and it is determined whether or not the deviation amount ΔT is a positive value. When the deviation amount ΔT is positive, the heat source side control unit 31 determines that the amount of the refrigerant is not insufficient, and proceeds to step ST6. If the deviation amount ΔT is negative, the heat source side control unit 31 determines that the amount of the refrigerant is insufficient, and proceeds to step ST7. At this time, it is desirable that the temperature efficiency T of the first supercooler 22 takes a moving average of a plurality of temperature efficiencies T different in time, rather than using an instantaneous value. By taking a moving average of a plurality of temperature efficiencies T that differ in time, the stability of the refrigeration cycle can also be considered. The determination threshold value Tm may be stored in advance in the storage unit 3c of the heat source side control unit 31, or may be set by input from a remote controller or a switch, and may be instructed by a remote device (not shown). May be set by.

If the result of determining the amount of refrigerant in step ST5 is appropriate for the amount of refrigerant, the heat source side control unit 31 outputs in step ST6 that the amount of refrigerant is appropriate. When the amount of the refrigerant is appropriate, the fact that the amount of the refrigerant is appropriate is displayed on, for example, a display unit (not shown) such as an LED or a liquid crystal display arranged in the refrigerating apparatus 1, or the amount of the refrigerant is appropriate. A signal to that effect is transmitted to a remote device (not shown).

When the refrigerant amount determination result in step ST5 is insufficient, the heat source side control unit 31 outputs in step ST7 that the amount of refrigerant is abnormal. When the amount of refrigerant is abnormal, for example, an alarm indicating that the amount of refrigerant is abnormal is displayed on a display unit (not shown) such as an LED or a liquid crystal display arranged in the refrigerating apparatus 1, or the amount of refrigerant is abnormal. A signal indicating that is abnormal is transmitted to a remote device (not shown). If the amount of the refrigerant is abnormal, it may be urgent, so it may be configured to directly notify the service person of the occurrence of the abnormality through a telephone line or the like.

In the above embodiment, the temperature efficiency T is calculated in step ST2, and it is determined in steps ST3 and ST4 whether or not to determine the amount of the refrigerant. However, in steps ST3 and ST4. After, step ST2 may be executed. By calculating the temperature efficiency T after determining whether or not to determine the amount of the refrigerant, the amount of processing performed by the heat source side control unit 31 can be reduced.

As described above, in this embodiment, the temperature efficiency T is used to determine the amount of the refrigerant flowing in the refrigerant circuit 10 of the refrigerating apparatus 1. Therefore, even if the refrigerant leaks, it is determined. , Refrigerant leakage can be detected at an early stage.

Further, in this embodiment, the operating state of the refrigerating device 1 is acquired, and when the operating state of the refrigerating device 1 corresponds to the "exception condition for determining the amount of refrigerant", the amount of refrigerant using the temperature efficiency T is used. Since the determination is not performed, the possibility of erroneous determination of the amount of refrigerant is suppressed. As a result, in this embodiment, the amount of the refrigerant can be set to an appropriate amount, so that the cost of the refrigerant can be reduced. Further, in this embodiment, since the amount of the refrigerant is an appropriate amount, even if the refrigerant leaks, the amount of the refrigerant released to the atmosphere can be reduced. Further, in this embodiment, since the amount of the refrigerant is an appropriate amount, even if the operation of the expansion valve or the like becomes abnormal and liquid back occurs, the amount of liquid back to the compressor 21 is increased. Can be reduced. Therefore, the refrigerating apparatus 1 of this embodiment has improved reliability.

In the operation control described above, the control for specifying the condensation temperature and the evaporation temperature is not performed, but for example, the control may be performed so that the condensation temperature and the evaporation temperature are constant. Further, for example, it is not necessary to control the condensation temperature and the evaporation temperature by setting the operating frequency of the compressor 21 and the rotation speed of the heat source side fan 27 of the heat source side unit 2 as constant values. Further, for example, control may be performed so that either the condensation temperature or the evaporation temperature becomes the target value. By controlling the operating state of the refrigerating apparatus 1 to a certain condition, the fluctuation of the operating state amount that fluctuates according to the supercooling degree and the supercooling degree of the first supercooler 22 becomes small, and the threshold value can be easily determined. , It becomes easy to judge that the amount of refrigerant is insufficient.

Further, by applying the refrigerant amount determination operation of this embodiment to the refrigerant filling work at the initial stage of installation of the refrigerating device 1 or the refrigerant filling work when the refrigerant is once discharged and refilled at the time of maintenance, the refrigerant filling work is performed. It is possible to shorten the time and reduce the load on the operator.

[Modification 1]
FIG. 13 is a modification 1 of FIG. Compared with the refrigerating apparatus 1 shown in FIG. 1, the heat source side unit 2A of the refrigerating apparatus 1A of the modified example 1 has a second supercooler 26 located downstream of the first supercooler 22 as shown in FIG. Has more. The second supercooler 26 corresponds to the "supercooler" of the present invention. The second supercooler 26 is configured to include, for example, a double pipe or a plate heat exchanger, and has a high pressure refrigerant flowing in the heat source side refrigerant circuit 10b and an intermediate pressure flowing in the first injection circuit 71A. It exchanges heat with the refrigerant. A part of the refrigerant that has passed through the second supercooler 26 is expanded by the injection amount adjusting valve 72 to become an intermediate pressure refrigerant, and exchanges heat with the refrigerant that has passed through the second supercooler 26. As a result, in the second modification, the high-pressure refrigerant flowing from the receiver 25 and exchanging heat in the second supercooler 26 is further supercooled. Further, the intermediate pressure refrigerant flowing in from the injection amount adjusting valve 72 and exchanging heat in the second supercooler 26 becomes a refrigerant having a high degree of dryness, and the compressor 21 is used to lower the discharge temperature of the compressor 21. It is injected to the suction side. The refrigerant determination operation in the first modification is performed using the temperature efficiency of the first supercooler 22, the temperature efficiency of the second supercooler 26, or the temperature efficiency of the first supercooler 22 and the second supercooler 26. I just need to be. In the first modification, the first supercooler 22 may be omitted, and the refrigerant flowing out of the receiver 25 may flow into the second supercooler 26.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. That is, the configuration of the above embodiment may be appropriately improved, or at least a part thereof may be replaced with another configuration. Further, the configuration requirement without particular limitation on the arrangement is not limited to the arrangement disclosed in the embodiment, and can be arranged at a position where the function can be achieved.

1 Refrigeration device, 1A refrigeration device, 2 heat source side unit, 2A heat source side unit, 3 control unit, 3a acquisition unit, 3b calculation unit, 3c storage unit, 3d drive unit, 3e input unit, 3f output unit, 4 user side unit 5, Overcooling heat exchanger, 6 liquid refrigerant extension pipe, 7 gas refrigerant extension pipe, 10 refrigerant circuit, 10a user side refrigerant circuit, 10b heat source side refrigerant circuit, 21 compressor, 22 first supercooler, 23 heat source side Heat exchanger, 24 accumulator, 25 receiver, 26 second supercooler, 27 heat source side fan, 28 liquid side closure valve, 29 gas side closure valve, 31 heat source side control unit, 32 user side control unit, 33a suction temperature sensor , 33b Discharge temperature sensor, 33c Suction outside air temperature sensor, 33d Supercooler high pressure side outlet temperature sensor, 33e User side heat exchange inlet temperature sensor, 33f User side heat exchange outlet temperature sensor, 33g Suction air temperature sensor, 34a Suction pressure sensor , 34b Discharge pressure sensor, 41 User side expansion valve, 42 User side heat exchanger, 43 User side fan, 71 1st injection circuit, 71A 1st injection circuit, 72 Injection amount adjustment valve, 73 2nd injection circuit, 74 Capillary Tube, 75 electromagnetic valve for suction injection, T temperature efficiency, T1 temperature efficiency threshold, T2 temperature efficiency threshold, T3 temperature efficiency threshold.

Claims (10)

A heat source side unit having a heat source side heat exchanger and a supercooler functioning as a compressor and a condenser, and at least one user side unit having a user side expansion valve and a user side heat exchanger functioning as an evaporator. Is a refrigerating device that is connected by piping and has a refrigerant circuit that circulates the refrigerant.
A first temperature sensor that detects the condensation temperature of the refrigerant, or a discharge pressure sensor that detects the pressure of the refrigerant discharged by the compressor.
A second temperature sensor that detects the evaporation temperature of the refrigerant, or a suction pressure sensor that detects the pressure of the refrigerant sucked into the compressor.
The pressure detected by the discharge pressure sensor is obtained by saturation conversion, or the condensation temperature detected by the first temperature sensor or the pressure detected by the suction pressure sensor is saturated and obtained. Alternatively, a drive unit that controls the operating frequency of the compressor so that the evaporation temperature detected by the second temperature sensor becomes constant.
The degree of supercooling of the refrigerant at the outlet of the supercooler, or the degree of supercooling divided by the maximum temperature difference of the supercooler, is used in the refrigerant circuit using the temperature efficiency of the supercooler. A refrigerant amount determination unit that determines the amount of filled refrigerant, and a refrigerant amount determination unit.
Refrigeration equipment with. Further, a heat source side fan for blowing air to the heat source side heat exchanger is provided.
The drive unit
The refrigerating apparatus according to claim 1, wherein the operating frequency of the compressor and the rotation speed of the heat source side fan are controlled so that the condensation temperature or the evaporation temperature becomes constant. A heat source side unit having a heat source side heat exchanger and a supercooler functioning as a compressor and a condenser, and at least one user side unit having a user side expansion valve and a user side heat exchanger functioning as an evaporator. Is a refrigerating device that is connected by piping and has a refrigerant circuit that circulates the refrigerant.
A heat source side fan that blows air to the heat source side heat exchanger,
A drive unit that controls the operating frequency of the compressor and the rotation speed of the fan on the heat source side to a constant value.
The degree of supercooling of the refrigerant at the outlet of the supercooler, or the degree of supercooling divided by the maximum temperature difference of the supercooler, is used in the refrigerant circuit using the temperature efficiency of the supercooler. A refrigerant amount determination unit that determines the amount of filled refrigerant, and a refrigerant amount determination unit.
Refrigeration equipment with. The refrigerant amount determination unit acquires the operating state of the refrigerating apparatus and does not determine the amount of the refrigerant when the determination of the amount of the refrigerant may be erroneous.
The refrigerating apparatus according to claim 2 or 3. If there is a possibility that the determination of the amount of the refrigerant may be erroneous, the amount of the high-pressure side refrigerant from the heat source side heat exchanger to the inlet of the utilization side expansion valve is temporarily reduced, and the amount of the high pressure side refrigerant is temporarily reduced from the outlet of the utilization side expansion valve. This is the case where the low-pressure side refrigerant up to the suction side of the compressor temporarily increases.
The refrigerating apparatus according to claim 4. Further equipped with a user-side fan for blowing air to the user-side heat exchanger,
The high-pressure side refrigerant from the heat source-side heat exchanger to the inlet of the utilization-side expansion valve temporarily decreases, and the low-pressure side refrigerant from the outlet of the utilization-side expansion valve to the suction side of the compressor temporarily increases. If this is the case, the amount of air blown by the user-side fan is temporarily reduced.
The refrigerating apparatus according to claim 5. The high-pressure side refrigerant from the heat source-side heat exchanger to the inlet of the utilization-side expansion valve temporarily decreases, and the low-pressure side refrigerant from the outlet of the utilization-side expansion valve to the suction side of the compressor temporarily increases. If so, it is a case of pulling down the refrigerating device.
The refrigerating apparatus according to claim 5. An injection circuit that injects a part of the refrigerant cooled by the heat source side heat exchanger into the compressor, and
Further provided with an on-off valve provided in the injection circuit,
The high-pressure side refrigerant from the heat source-side heat exchanger to the inlet of the utilization-side expansion valve temporarily decreases, and the low-pressure side refrigerant from the outlet of the utilization-side expansion valve to the suction side of the compressor temporarily increases. If this is the case, the on-off valve is opened.
The refrigerating apparatus according to claim 5. When the determination of the amount of the refrigerant may be erroneous, it is a case where the amount of air blown by the fan on the heat source side is temporarily reduced.
The refrigerating apparatus according to claim 4. When the determination of the amount of the refrigerant may be an erroneous determination, it is a certain period of time while the compressor is stopped and after the compressor is started.
The refrigerating apparatus according to claim 4.

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