WO2017199391A1

WO2017199391A1 - Refrigerating device

Info

Publication number: WO2017199391A1
Application number: PCT/JP2016/064857
Authority: WO
Inventors: 洋貴佐藤; 佐多　裕士; 池田　隆
Original assignee: 三菱電機株式会社
Priority date: 2016-05-19
Filing date: 2016-05-19
Publication date: 2017-11-23
Also published as: JP6611929B2; JPWO2017199391A1

Abstract

This refrigerating device comprises: a refrigerant circuit in which a refrigerant is circulated in a compressor, a heat source-side heat exchanger, a super-cooling heat exchanger, a load-side expansion device, and a load-side heat exchanger; and a control unit that controls a refrigeration cycle in the refrigerant circuit. The control unit comprises: a refrigeration cycle control means for controlling the refrigeration cycle; a refrigerant volume determination means for monitoring the temperature efficiency of the super-cooling heat exchanger, determining that the volume of the refrigerant filling the refrigerant circuit is normal when the temperature efficiency is at least a predetermined threshold value, and determining that there is a refrigerant leak when the temperature efficiency is less than the threshold value; and an auxiliary determination means for determining whether the value of a parameter associated with the temperature of gas discharged from the compressor deviates from a predetermined range when the refrigerant volume determination means has determined that there is a refrigerant leak, and determining that the refrigerant volume is insufficient when the value of the parameter has deviated from the range.

Description

Refrigeration equipment

The present invention relates to a refrigeration apparatus for determining a refrigerant shortage.

In a refrigeration system, excess or deficiency of the refrigerant amount causes a decrease in the capacity of the refrigeration system and damages to the components. For this reason, some conventional refrigeration apparatuses have a function of determining whether there is an excess or deficiency in the amount of refrigerant charged in the refrigerant circuit in order to prevent occurrence of problems due to excess or deficiency in the amount of refrigerant. .

An example of a method for detecting refrigerant leakage in a refrigeration apparatus is disclosed in Patent Document 1. Patent Document 1 discloses that the control means calculates a temperature difference between the inlet refrigerant temperature and the outlet refrigerant temperature of the subcooler, and determines that the refrigerant leaks when the calculated temperature difference is smaller than a set value. .

Further, another method for detecting a shortage of the refrigerant amount is disclosed in Patent Document 2. Patent Document 2 includes a refrigerant shortage determination unit that determines whether the refrigerant amount is insufficient based on at least one of the operating state quantity that varies according to the degree of refrigerant subcooling or the degree of subcooling at the outlet of the subcooler. A refrigerating and air-conditioning apparatus provided is disclosed.

In the refrigeration apparatus disclosed in Patent Document 1 and Patent Document 2, the presence or absence of refrigerant leakage is determined by a change in the degree of supercooling, and the presence or absence of refrigerant leakage is determined using a threshold for one parameter, the degree of supercooling. There are two problems as follows.

The first problem is that in the case of the method disclosed in Patent Document 1, the degree of supercooling varies depending on the operating conditions. Thereby, erroneous detection is likely to occur in the determination of refrigerant leakage. A second problem is that a false detection condition in which the change in the degree of supercooling exceeds a threshold value may occur in a short time during operation of the refrigeration apparatus. That is, there is a risk of being erroneously determined. This problem is improved as compared with the method disclosed in Patent Document 1, but may also occur in the method disclosed in Patent Document 2.

In order to prevent the refrigeration apparatus from determining that the refrigerant leaks even under erroneous detection conditions, it is necessary to increase the charging frequency of the refrigerant amount or to set the threshold value low. When the charging amount of the refrigerant amount is increased, there is a problem that the operation cost is increased. If the threshold value is set low, erroneous detection can be prevented, but if the refrigerant leakage does not increase, the refrigeration apparatus may not be able to detect the refrigerant leakage.

As an example of a method for preventing erroneous detection of refrigerant shortage, Patent Literature 3 discloses a refrigerant shortage determination method using the temperature efficiency of a supercooling heat exchanger as a criterion for refrigerant shortage. In Patent Document 3, when the temperature efficiency of the supercooling heat exchanger is calculated at regular time intervals, if the calculated temperature efficiency is smaller than the threshold, it is determined that there is a refrigerant leak, and the refrigerant leak is detected N times continuously. It is disclosed to determine that the refrigerant is insufficient.

Japanese Patent No. 3601130 Japanese Patent No. 5334909 JP 2012-132039 A

In the method disclosed in Patent Document 3, erroneous detection is prevented by performing refrigerant leakage determination using the temperature efficiency of the supercooling heat exchanger at least N times, but until the period for determining N times at least has elapsed. Insufficient amount of refrigerant cannot be detected. Therefore, if the refrigerant shortage occurs before the refrigeration apparatus detects the refrigerant shortage, the compressor may break down before the refrigeration apparatus stops due to an abnormality of the compressor.

The present invention has been made to solve the above-described problems, and provides a refrigeration apparatus that prevents a compressor from being damaged due to a lack of refrigerant.

A refrigeration apparatus according to the present invention controls a refrigerant circuit that circulates refrigerant to a compressor, a heat source side heat exchanger, a supercooling heat exchanger, a load side expansion device, and a load side heat exchanger, and a refrigeration cycle in the refrigerant circuit. A control unit that monitors the temperature efficiency of the refrigeration cycle control means for controlling the refrigeration cycle and the supercooling heat exchanger, and the temperature efficiency is equal to or higher than a predetermined threshold value. If there is, the refrigerant amount determining means that determines that the refrigerant amount charged in the refrigerant circuit is normal and the temperature efficiency is less than the threshold value is that there is a refrigerant leak; and If it is determined that the parameter value related to the temperature of the discharge gas of the compressor deviates from a predetermined range, and if the parameter value deviates from the range, Insufficient amount of refrigerant The auxiliary judgment means for determining that the one having a.

The present invention determines whether or not the value of the parameter related to the temperature of the discharge gas of the compressor deviates from a predetermined range when it is determined that there is a refrigerant leak using the temperature efficiency of the supercooling heat exchanger. If the parameter value deviates from the predetermined range, it is determined that the refrigerant is insufficient. Therefore, the refrigerant shortage can be detected before detecting the refrigerant shortage using the temperature efficiency, and the compressor It can be prevented from stopping due to abnormal temperature, and the compressor can be prevented from malfunctioning.

It is a refrigerant circuit diagram which shows one structural example of the freezing apparatus in Embodiment 1 of this invention. It is a refrigerant circuit figure which shows another structural example of the refrigeration apparatus in Embodiment 1 of this invention. It is a refrigerant circuit figure which shows another structural example of the refrigeration apparatus in Embodiment 1 of this invention. It is a functional block diagram which shows one structural example of the freezing apparatus shown to FIG. 1A. It is a block diagram which shows the example of 1 structure of the controller shown to FIG. 1A. In the refrigerating apparatus shown in FIG. 1A, it is a figure for demonstrating the temperature change of a refrigerant | coolant when a refrigerant | coolant amount is normal. It is a figure for demonstrating the temperature change of a refrigerant | coolant when the refrigerant | coolant amount is insufficient in the refrigeration apparatus shown to FIG. 1A. 1B is a ph diagram for explaining an example of parameters for detecting a sign of a shortage of refrigerant in the refrigeration apparatus shown in FIG. 1A. FIG. 1B is a ph diagram for explaining an example of parameters for detecting a sign of a shortage of refrigerant in the refrigeration apparatus shown in FIG. 1A. FIG. It is a flowchart which shows the procedure of the refrigerant | coolant shortage determination method in a comparative example. It is a flowchart which shows the operation | movement procedure of the refrigerant | coolant shortage determination method which the refrigeration apparatus in Embodiment 1 of this invention performs. It is a refrigerant circuit figure which shows the example of 1 structure of the freezing apparatus in Embodiment 2 of this invention. FIG. 11 is a ph diagram for explaining an example of parameters for detecting a sign of insufficient refrigerant amount in the refrigeration apparatus shown in FIG. 10.

Embodiment 1 FIG.
The configuration of the refrigeration apparatus in Embodiment 1 will be described.
(Outline of configuration of refrigeration equipment)
FIG. 1A is a refrigerant circuit diagram illustrating a configuration example of a refrigeration apparatus in Embodiment 1 of the present invention. The refrigeration apparatus includes a heat source side unit 100 and a load side unit 200. The heat source side unit 100 includes a compressor 1, an oil separator 2, a heat source side heat exchanger 3, a liquid receiver 4, a supercooling heat exchanger 5, an accumulator 8, and a controller 120. The load side unit 200 includes a load side expansion device 6 and a load side heat exchanger 7. The load side expansion device 6 is, for example, an expansion valve.

In the heat source side unit 100, the compressor 1, the oil separator 2, the heat source side heat exchanger 3, the liquid receiver 4, the supercooling heat exchanger 5 and the accumulator 8 are connected by a pipe 13. In the load side unit 200, the load side expansion device 6 and the load side heat exchanger 7 are connected by a pipe 12.

The piping 12 of the load side unit 200 is connected to the piping 13 of the heat source side unit 100 via the liquid extension piping 10 and the gas extension piping 11. Refrigerant that sequentially circulates refrigerant to the compressor 1, the oil separator 2, the heat source side heat exchanger 3, the receiver 4, the supercooling heat exchanger 5, the load side expansion device 6, the load side heat exchanger 7, and the accumulator 8. A circuit is configured. Although not shown in FIG. 1A, a fan that supplies outside air to the heat source side heat exchanger 3 and the supercooling heat exchanger 5 is provided in the heat source side unit 100, and a fan that supplies air to the load side heat exchanger 7 is loaded. It is provided in the side unit 200.

The heat source side unit 100 is provided with an outside air temperature sensor TH6 that detects the temperature of the outside air heat exchanged with the refrigerant by the heat source side heat exchanger 3 as the outside air temperature THV6. A condensing temperature sensor TH5 that detects the refrigerant temperature as the condensing temperature THV5 is provided in a flow path from the outlet of the heat source side heat exchanger 3 to the inlet of the supercooling heat exchanger 5. In the configuration example shown in FIG. 1A, a liquid receiver 4 is provided between the heat source side heat exchanger 3 and the supercooling heat exchanger 5, and the condensation temperature sensor TH <b> 5 includes the heat source side heat exchanger 3 and the liquid receiver 4. Between the pipes 13.

A liquid refrigerant temperature sensor TH8 that detects the temperature of the refrigerant as the liquid refrigerant temperature THV8 is provided in the flow path from the outlet of the supercooling heat exchanger 5 to the inlet of the load side expansion device 6. An evaporating temperature sensor ET that detects the refrigerant temperature as the evaporating temperature ETV is provided in a flow path from the outlet of the load side expansion device 6 to the inlet of the load side heat exchanger 7. A discharge gas temperature sensor 51 that detects the temperature of the discharge gas of the compressor 1 is provided at the outlet of the compressor 1. An intake gas temperature sensor 52 that detects the temperature of the refrigerant sucked into the compressor 1 is provided at the suction port of the compressor 1.

Instead of the condensation temperature sensor TH5, a pressure sensor for detecting the refrigerant pressure is provided in a flow path from the outlet of the heat source side heat exchanger 3 to the inlet of the supercooling heat exchanger 5, and the pressure sensor is used as the condensation temperature THV5. The saturation temperature may be calculated from the pressure detected by. Further, instead of the evaporation temperature sensor ET, a pressure sensor for detecting the pressure of the refrigerant is provided in a flow path from the outlet of the load side expansion device 6 to the inlet of the load side heat exchanger 7, and the pressure sensor is used as the evaporation temperature ETV. The saturation temperature may be calculated from the detected pressure.

The flow of the refrigerant in the refrigerant circuit of the refrigeration apparatus shown in FIG. 1A will be described. In the first embodiment, the case where the refrigeration apparatus cools the space to be air-conditioned will be described. In this case, the heat source side heat exchanger 3 is a condenser, and the load side heat exchanger 7 is an evaporator. The high-temperature and high-pressure gas refrigerant discharged from the variable capacity compressor 1 flows into the heat source side heat exchanger 3 after the refrigeration oil contained in the refrigerant is separated by the oil separator 2. The high-temperature and high-pressure gas refrigerant flowing into the heat source side heat exchanger 3 is condensed in the heat source side heat exchanger 3 to become a high pressure liquid refrigerant (liquid state or gas-liquid two-phase state), and the high pressure liquid refrigerant is stored in the receiver 4. To do. The high-pressure liquid refrigerant accumulated in the liquid receiver 4 further becomes a supercooled liquid refrigerant by exchanging heat with the supercooling heat exchanger 5. The refrigerant that has become a high-pressure liquid in the subcooling heat exchanger 5 becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant in the load-side expansion device 6 of the load-side unit 200 and flows into the load-side heat exchanger 7. The low-temperature and low-pressure gas-liquid two-phase refrigerant becomes low-temperature and low-pressure gas refrigerant in the load-side heat exchanger 7, and the gas refrigerant returns to the compressor 1 through the accumulator 8.

In the first embodiment, a case where one load side unit 200 is connected to one heat source side unit 100 will be described. However, the number of load side units 200 connected to the heat source side unit 100 is one. The number is not limited and may be plural. The number of the load side units 200 provided in the refrigeration apparatus is arbitrary. Further, in the first embodiment, a description will be given of a refrigeration apparatus in which a refrigerant circuit is configured by connecting the heat source side unit 100 and the load side unit 200, but the refrigeration apparatus in the first embodiment is the same. It is not limited to such a configuration.

For example, at a place where an equipment supplier installs a refrigeration system, a heat source side unit 100 corresponding to a condensing unit and a load side unit 200 corresponding to a load side unit are joined by refrigerant piping including liquid piping and gas piping. It may be a refrigeration device in which a refrigerant circuit is configured by connection. Further, the refrigeration apparatus of the first embodiment may be configured such that the compressor 1 is installed indoors and the remote condensing unit including the heat source side heat exchanger 3 is installed outdoors. A configuration example of a refrigeration apparatus having a remote condensing unit will be described with reference to FIGS. 1B and 1C.

1B and 1C are refrigerant circuit diagrams showing another configuration example of the refrigeration apparatus in Embodiment 1 of the present invention. The refrigeration apparatus shown in FIG. 1B includes a compression unit 150 between the load side unit 200 and the heat source side unit 100. The compression unit 150 is installed indoors. The heat source side unit 100 includes a heat source side heat exchanger 3 and a supercooling heat exchanger 5. The compression unit 150 includes a compressor 1, an oil separator 2, a liquid receiver 4, an accumulator 8, and a controller 120. The compression unit 150 is provided with a pipe 14 connected to the compressor 1, the oil separator 2, the liquid receiver 4, and the accumulator 8. The piping 13 of the heat source unit 100 and the piping 14 of the compression unit 150 are connected via an extension piping 15. The pipe 14 of the compression unit 150 is connected to the pipe 12 of the load side unit 200 via the gas extension pipe 11 and the liquid extension pipe 10.

The configuration of the refrigeration apparatus shown in FIG. 1C will be described. The refrigeration apparatus illustrated in FIG. 1C includes a compression unit 151 between the load side unit 200 and the heat source side unit 100. In the configuration shown in FIG. 1B, the liquid receiver 4 is provided on the compression unit 150 side. However, the refrigeration apparatus shown in FIG. 1C has the exception that the liquid receiver 4 is provided on the heat source side unit 100. The configuration is the same as that shown in FIG. 1B.

As another configuration example, the refrigeration apparatus according to the first embodiment includes, for example, a compressor 1, a heat source side heat exchanger 3, a supercooling heat that configures a refrigerant circuit in one unit like a cooling unit. The exchanger 5, the load side expansion device 6, the load side heat exchanger 7, and other accessory devices may be provided, and these devices may be connected by piping.

Furthermore, the configuration of the refrigerant circuit in the first embodiment is not limited to the configuration shown in FIGS. 1A to 1C. For example, a four-way valve or the like that switches the refrigerant flow path may be provided in the refrigeration apparatus, and the refrigeration apparatus may be configured to switch between a cooling operation and a heating operation. When the refrigeration apparatus performs a heating operation, the heat source side heat exchanger 3 is an evaporator, and the load side heat exchanger 7 is a condenser. In this case, the supercooling heat exchanger 5 may be provided in the load side unit 200. 1A to 1C show a case where the oil separator 2, the liquid receiver 4 and the accumulator 8 are provided in the refrigerant circuit of the refrigeration apparatus. Some of these three devices are shown. It does not have to be provided, and all may not be provided.

(Configuration of controller 120)
Next, the configuration of the controller 120 shown in FIG. 1A will be described. FIG. 2 is a functional block diagram showing a configuration example of the refrigeration apparatus shown in FIG. 1A. The controller 120 includes a control unit 20 and a display unit 21.

The control unit 20 supplies air to the compressor 1, the load side expansion device 6, a fan 26 that supplies outside air to the heat source side heat exchanger 3 and the subcooling heat exchanger 5, and air to the load side heat exchanger 7. The fan 27 is connected via a signal line (not shown). The control unit 20 is connected to the condensing temperature sensor TH5, the liquid refrigerant temperature sensor TH8, the outside air temperature sensor TH6, the evaporation temperature sensor ET, the discharge gas temperature sensor 51, and the intake gas temperature sensor 52 via signal lines (not shown). Yes. The controller 20 receives temperature information, which is information on the temperature detected by each of these temperature sensors, from each temperature sensor via a signal line (not shown).

FIG. 3 is a block diagram showing a configuration example of the controller shown in FIG. 1A. As shown in FIG. 3, the control unit 20 performs refrigeration cycle control means 22 for controlling the refrigerant cycle, refrigerant amount determination means 23 for determining the appropriateness of the refrigerant amount charged in the refrigerant circuit, and appropriateness determination of the refrigerant amount. Auxiliary assistance means 24 to assist. The control unit 20 is, for example, a microcomputer. The control unit 20 includes a storage unit 122 that stores a program, and a CPU (Central Processing Unit) 121 that executes processing according to the program. The storage unit 122 is, for example, a nonvolatile memory. The storage unit 122 stores in advance information such as a threshold value and a range, which are determination criteria for refrigerant leakage and refrigerant shortage. In addition, the storage unit 122 also serves as a buffer memory that temporarily stores values and calculation results used for calculation of the refrigerant amount suitability determination. When the CPU 121 executes the program, the refrigeration cycle control unit 22, the refrigerant amount determination unit 23, and the auxiliary determination unit 24 are configured in the controller 120.

The display unit 21 displays the determination result received from the control unit 20 and various information. The display unit 21 is, for example, a 7-segment LED (Light Emitting Diode). As an example of the display method, the display unit 21 displays the numeral zero with a 7-segment LED when the refrigerant amount is normal, and displays the Roman letter “A” with the 7-segment LED when the refrigerant amount is insufficient. To do. “A” is an acronym for alarm. When there is a refrigerant leak, the display unit 21 may display any number among the numbers 1 to 9 on the 7-segment LED depending on the degree of the leakage. The number of 7-segment LEDs provided in the display unit 21 is not limited to one and may be plural. The display unit 21 may be a liquid crystal display.

The configuration of the control unit 20 shown in FIG. 3 will be described in detail. The refrigeration cycle control means 22 adjusts the opening degree of the load side expansion device 6 so that the degree of superheat coincides with a predetermined value. Further, the refrigeration cycle control means 22 controls the rotation speeds of the compressor 1 and the fan 26 of the heat source side heat exchanger 3 so that the temperature of the air-conditioning target space matches the set temperature.

The refrigerant amount determination means 23 monitors the temperature efficiency ε of the supercooling heat exchanger 5 in order to determine the suitability of the refrigerant amount charged in the refrigerant circuit. Specifically, when the operating state of the refrigeration apparatus does not correspond to a predetermined non-detectable condition, the temperature efficiency ε of the supercooling heat exchanger 5 is calculated, and is the temperature efficiency ε greater than or equal to a predetermined threshold value? Determine whether or not. The refrigerant amount determination means 23 determines that the refrigerant amount is normal when the temperature efficiency ε is equal to or greater than the threshold value, and determines that refrigerant leakage has occurred when the temperature efficiency ε is less than the threshold value. Further, the refrigerant amount determination means 23 determines that the refrigerant amount is insufficient when the case where the temperature efficiency ε is less than the threshold value continues for a predetermined number of times. In the first embodiment, the predetermined number of times is N (N is a positive integer of 2 or more). For example, N = 3. The “normal” refrigerant amount means that the refrigerant amount charged in the refrigerant circuit is appropriate.

When it is determined that the refrigerant amount is insufficient, the refrigerant amount determination unit 23 instructs the refrigeration cycle control unit 22 to stop the refrigeration cycle. The refrigerant amount determination means 23 outputs the determination result to the display unit 21 when the refrigerant amount is normal and when the refrigerant amount is insufficient.

Here, the principle by which the refrigerant amount determination means 23 determines the suitability of the refrigerant amount using the temperature efficiency ε will be described. First, the relationship between the refrigerant charge amount and the degree of supercooling will be described as a premise of the principle of determining the suitability of the refrigerant amount. FIG. 4 is a diagram for explaining the temperature change of the refrigerant when the refrigerant amount is normal in the refrigeration apparatus shown in FIG. 1A.

4, the vertical axis indicates the temperature of the refrigerant, and the horizontal axis indicates the position in the refrigerant circuit. FIG. 4 shows that the temperature is higher on the upper side of the vertical axis. The horizontal axis shown in FIG. 4 shows the refrigerant path from the heat source side heat exchanger 3 through the supercooling heat exchanger 5 to the pipe 13 on the outlet side of the supercooling heat exchanger 5. In the pipe 13 on the outlet side of the supercooling heat exchanger 5, the refrigerant is in a liquid state, and therefore, the pipe 13 is indicated as “liquid pipe” in FIG. An arrow 501 shown in FIG. 4 indicates a change in the temperature of the refrigerant in each refrigerant path shown on the horizontal axis in FIG. 4 when the refrigerant amount is normal.

When the refrigerant amount is normal, the gas-liquid two-phase refrigerant flowing out from the heat source side heat exchanger 3 is separated into gas and liquid by the receiver 4, and the receiver 4 is in a saturated liquid state in which the liquid refrigerant is stored. Therefore, the liquid refrigerant from the liquid receiver 4 flows into the supercooling heat exchanger 5, and all the heat exchange performed by the supercooling heat exchanger 5 contributes to the supercooling of the liquid refrigerant.

FIG. 5 is a diagram for explaining the temperature change of the refrigerant when the refrigerant amount is insufficient in the refrigeration apparatus shown in FIG. 1A. In FIG. 5, the vertical axis indicates the temperature of the refrigerant, and the horizontal axis indicates the position in the refrigerant circuit. The vertical axis and horizontal axis shown in FIG. 5 are the same as the vertical axis and horizontal axis shown in FIG. An arrow 502 shown in FIG. 5 indicates the temperature change of the refrigerant in each refrigerant path indicated by the horizontal axis in FIG. 5 when the refrigerant amount is insufficient. In FIG. 5, for comparison, the arrow 501 shown in FIG. 4 is indicated by a broken line.

When the amount of the refrigerant is insufficient, the refrigerant at the outlet of the heat source side heat exchanger 3 is in a dry state, the liquid refrigerant is not stored in the liquid receiver 4, and as shown by the arrow 502 in FIG. A gas-liquid two-phase refrigerant flows into the heat exchanger 5. Therefore, the heat exchange performed by the supercooling heat exchanger 5 is consumed for condensing and supercooling the gas-liquid two-phase refrigerant. As a result, as shown in FIG. 5, the degree of supercooling of the arrow 502 is reduced compared to the arrow 501.

From the graphs shown in FIG. 4 and FIG. 5, it can be seen that the shortage of the refrigerant amount affects the degree of supercooling. Although it is conceivable to use the degree of supercooling as a parameter for determining the suitability of the refrigerant quantity, the refrigerant quantity judging means 23 uses the temperature efficiency ε of the supercooling heat exchanger 5. The reason why the refrigerant amount determination means 23 uses the temperature efficiency ε of the supercooling heat exchanger 5 as a parameter for determining whether or not the refrigerant amount is appropriate will be described below.

The temperature efficiency ε of the supercooling heat exchanger 5 is the refrigerant subcooling degree (condensation temperature THV5−liquid refrigerant temperature THV8) at the outlet of the supercooling heat exchanger 5 and the maximum temperature difference (condensation) of the supercooling heat exchanger 5. Temperature THV5−outside air temperature THV6). The temperature efficiency ε of the supercooling heat exchanger 5 is expressed by the following formula (1).

Referring to Equation (1), the equation on the right side for calculating the temperature efficiency ε includes the degree of supercooling. Therefore, the temperature efficiency ε of the supercooling heat exchanger 5 is suitable as a parameter for determining the suitability of the refrigerant amount. Further, the temperature efficiency ε of the supercooling heat exchanger 5 indicates the performance of the supercooling heat exchanger 5, and has an advantage that variation due to operating conditions is smaller than the degree of supercooling. Therefore, if the temperature efficiency ε is used as a parameter for determining whether or not the refrigerant amount is appropriate, it is not necessary to set a threshold value for each operating condition, and the accuracy of determining whether or not the refrigerant amount is appropriate can be improved.

As described above, the refrigerant amount determination means 23 determines the suitability of the refrigerant amount by using the temperature efficiency ε of the supercooling heat exchanger 5 that is less fluctuated by operating conditions than the degree of supercooling. However, if the suitability of the refrigerant amount is determined based on one calculation result, it is conceivable that the refrigerant amount determination unit 23 erroneously determines when the temperature sensor erroneously detects. In the first embodiment, in order to prevent such an erroneous determination, the refrigerant amount determination unit 23 determines that the refrigerant amount is insufficient when the temperature efficiency ε is less than the threshold value N times consecutively. Yes. Furthermore, in order to enhance prevention of erroneous determination, the refrigerant amount determination means 23 calculates a plurality of temperature efficiencies ε in a fixed time, obtains an average value of the calculated temperature efficiencies ε, and compares the calculated average value with a threshold value. May be.

Subsequently, the configuration of the auxiliary determination means 24 shown in FIG. 3 will be described. The auxiliary determination unit 24 refers to a value other than the temperature efficiency ε as information indicating a sign of a refrigeration amount shortage, and detects the shortage of the refrigerant amount earlier than the refrigerant amount determination unit 23 determines. Specifically, the auxiliary determination means 24 determines whether or not each value deviates from a predetermined range for parameters related to the discharge gas temperature and the discharge gas temperature of the compressor 1. . The auxiliary determination unit 24 determines that the refrigerant amount is insufficient when at least one of the auxiliary determination units deviates from a predetermined range.

When the auxiliary determination unit 24 determines that the refrigerant amount is insufficient, the auxiliary determination unit 24 outputs the determination result to the display unit 21 and instructs the refrigeration cycle control unit 22 to stop the refrigeration cycle. The auxiliary determination means 24 indicates that the refrigerant amount deficiency was not detected when both the discharge gas temperature of the compressor 1 and the parameters related to the discharge gas temperature are within the predetermined ranges. The amount determining means 23 is notified.

Parameters relating to the temperature of the discharge gas of the compressor 1 include, for example, the degree of superheat at the suction port of the compressor 1 and the pressure of the refrigerant in the load side heat exchanger 7. Hereinafter, the superheat degree of the suction port of the compressor 1 is set as a parameter P1, and the refrigerant pressure in the load side heat exchanger 7 is set as a parameter P2. In the case of the parameter P1, the fact that the degree of superheat of the suction port of the compressor 1 is equal to or higher than the upper limit of a predetermined range corresponds to a shortage of the refrigerant amount. In the case of the parameter P2, the fact that the pressure of the refrigerant in the load-side heat exchanger 7 is equal to or lower than the lower limit of a predetermined range corresponds to the shortage of the refrigerant amount.

It will be explained that the shortage of the refrigerant amount raises the temperature of the discharge gas of the compressor 1. When the amount of refrigerant circulating through the refrigerant circuit is small, the refrigerant is completely vaporized by the load-side heat exchanger 7 and is sucked into the compressor 1 in a state where the temperature is excessively high after drying. Since the compressor 1 sucks in the refrigerant whose temperature has become excessively high, the temperature of the discharge gas of the compressor 1 rises. The case where the value detected by the discharge gas temperature sensor 51 is equal to or greater than the upper limit value in a predetermined range corresponds to the shortage of the refrigerant amount. Note that the temperature of the discharge gas of the compressor 1 suddenly rises and becomes equal to or higher than the upper limit of a predetermined range, and the refrigeration cycle control means 22 stops the refrigeration cycle according to the instruction of the auxiliary determination means 24. Corresponds to the case where the operation is stopped due to an abnormal postponement. Abnormal postponement is that the operation is automatically stopped when the refrigeration apparatus detects an abnormality of the compressor 1 in accordance with a preset safety standard.

It will be explained that the parameters P1 and P2 are related to the temperature of the discharge gas of the compressor 1. 6 and 7 are ph diagrams for explaining an example of parameters for detecting a sign of a shortage of the refrigerant amount in the refrigeration apparatus shown in FIG. 1A. 6 and 7, the vertical axis represents pressure [MPa], and the horizontal axis represents specific enthalpy [kJ / kg]. 6 and 7 show a refrigeration cycle comprising an evaporation process, a compression process, a condensation process, and an expansion process. Point J1 → point J2 corresponds to the evaporation process, point J2 → point J3 corresponds to the compression process, point J3 → point J4 corresponds to the condensation process, and point J4 → point J1 corresponds to the expansion process.

Referring to FIG. 6, it will be described that the parameter P1 is related to the temperature of the discharge gas of the compressor 1. SH (super heat) shown in FIG. 6 corresponds to the degree of superheat of the suction port of the compressor 1. When the degree of superheat at the suction port of the compressor 1 increases and the point J2 changes to the point J2 'as shown in FIG. 6, the point J3 changes to the point J3' as shown by the broken line. As a result, the temperature of the discharge gas of the compressor 1 also increases. The auxiliary determination means 24 calculates the difference between the temperature detected by the intake gas temperature sensor 52 and the evaporation temperature ETV to determine the superheat degree SH. And the auxiliary | assistant determination means 24 determines with the refrigerant | coolant amount being insufficient, when the superheat degree SH is more than the upper limit of the predetermined range.

Referring to FIG. 7, it will be described that the parameter P2 relates to the discharge gas of the compressor 1. The pressure Ps shown in FIG. 7 indicates the pressure of the refrigerant in the load side heat exchanger 7. When the refrigerant pressure Ps in the load-side heat exchanger 7 decreases and decreases to the pressure Ps ′ as shown in FIG. 7, the point J3 transitions to the point J3 ′ as shown by the broken line. As a result, the temperature of the discharge gas of the compressor 1 also increases. The auxiliary determination unit 24 obtains a saturation pressure from the temperature of the evaporation temperature ETV as the refrigerant pressure of the load side heat exchanger 7, and the refrigerant pressure of the load side heat exchanger 7 is equal to or lower than a lower limit value in a predetermined range. In this case, it is determined that the refrigerant amount is insufficient.

A pressure sensor that detects the pressure of the refrigerant in the load side heat exchanger 7 may be provided in the pipe 12 between the load side expansion device 6 and the load side heat exchanger 7. Moreover, since the pressure of the refrigerant | coolant of the load side heat exchanger 7 tends to fall when the number of starts / stops of the compressor 1 increases, the frequency of the number of starts / stops of the compressor 1 is larger than a predetermined value. This may be included when the parameter P2 deviates from a predetermined range.

The parameters related to the discharge gas of the compressor 1 are not limited to the parameters P1 and P2 described above, and other parameters that can detect signs that occur when the refrigerant is insufficient may be appropriately set in the control unit 20.

(Procedure for refrigerant shortage determination in comparative example)
Next, the refrigerant shortage determination method in the comparative example will be described. FIG. 8 is a flowchart showing the procedure of the refrigerant shortage determination method in the comparative example. FIG. 8 corresponds to a procedure in which the refrigerant amount determination unit 23 executes the determination of whether the refrigerant amount is appropriate, but the auxiliary determination unit 24 does not determine the appropriateness of the refrigerant amount.

For the determination of the refrigerant amount, an average temperature efficiency εAve, which is an average value of the temperature efficiency ε, is used. The threshold value of the temperature efficiency ε is expressed as εLine. In addition, when the refrigerant amount determination means 23 determines the suitability of the refrigerant amount, M is a variable for counting the number of times that the average temperature efficiency εAve is continuously less than the threshold value. Possible values of the variable M are integers of 0 or more.

As shown in FIG. 8, when the refrigeration apparatus is started after the refrigerant is filled, the refrigeration cycle control means 22 starts controlling the refrigeration cycle. The refrigerant amount determination means 23 sets zero as an initial value for the variable M (step S101), and performs a determination operation for periodically determining whether the refrigerant amount is appropriate or not during operation of the refrigeration apparatus. In the determination operation, first, the refrigerant amount determination means 23 acquires temperature information from the condensation temperature sensor TH5, the outside air temperature sensor TH6, the liquid refrigerant temperature sensor TH8, and the evaporation temperature sensor ET as data indicating the operation state, and the compressor 1 Information indicating the state is acquired from each component device including (step S102). Subsequently, the refrigerant amount determination means 23 determines whether or not the current operation state corresponds to the undetectable condition based on the acquired data (step S103).

Here, an example of the detection impossible condition will be described.
Undetectable condition 1: When the compressor 1 is stopped. The reason for making the detection impossible is that the cause of the stop of the compressor 1 may be an abnormality that has occurred in the refrigeration apparatus.
Undetectable condition 2: 30 minutes after starting the refrigeration system. The reason why the detection is impossible is that the temperature efficiency ε is not stable for the first 10 to 20 minutes after the refrigeration apparatus is started.
Undetectable condition 3: When the outside air temperature is a low outside temperature lower than a predetermined temperature. The reason why detection is impossible is that when the outside air temperature is low, the refrigeration cycle control means 22 tries to keep the refrigerant on the inlet side of the heat source side heat exchanger 3 at a high pressure, and the heat source side heat exchanger 3 and the supercooling heat exchanger. This is because the temperature efficiency ε is lowered to reduce the air volume of the fan 26 that blows air to 5 and there is a possibility of erroneous detection.

Non-detectable condition 4: When the outside air temperature is a high outside air temperature that is outside the predetermined operating range. The reason why the detection is impossible is that the refrigerant hardly radiates heat in the heat source side heat exchanger 3, the temperature efficiency ε is lowered, and there is a possibility of erroneous detection.
Undetectable condition 5: When the temperature difference between the condensation temperature THV5 and the outside air temperature THV6 is larger than a predetermined value. The reason why detection is impossible is that the denominator on the right side of equation (1) becomes excessive, and there is a possibility of erroneous detection.
Detection impossible condition 6: When the degree of superheat is smaller than a predetermined value. The reason why the detection is impossible is that the superheat degree is reduced when there is no excess refrigerant in the liquid receiver 4, but if there is an excess refrigerant in the accumulator 8, it does not correspond to a shortage of the refrigerant amount.

In the non-detectable conditions 1 to 6 described above, the value of the temperature efficiency ε may be smaller than the threshold value εLine even if the refrigerant amount is normal. Therefore, under such conditions, the refrigerant amount determination means 23 may erroneously determine whether or not the refrigerant amount is appropriate, so that the determination of the appropriateness of the refrigerant amount is not performed. The undetectable conditions 1 to 6 are examples. In addition to the non-detectable conditions 1 to 6, even if the refrigerant amount is normal due to the effect of the condensation temperature THV5, the temperature difference between the condensation temperature THV5 and the outside air temperature THV6, and the outside air temperature THV6, the temperature efficiency calculated by the equation (1) There may be a case where ε becomes smaller than the threshold εLine. The detection impossible condition in such a case is referred to as a detection impossible condition 7.

Return from the description of the undetectable condition to the description of the flowchart shown in FIG. As a result of the determination in step S103, when the current refrigeration apparatus meets any one of the undetectable conditions 1 to 7, the refrigerant amount determination means 23 stores error information in the storage unit 122 as an invalid value ( Step S104). On the other hand, if the result of determination in step S103 is that the current refrigeration apparatus does not fall under any of the undetectable conditions 1 to 7, the refrigerant amount determination means 23 uses the equation (1) to calculate the temperature of the supercooling heat exchanger 5 The efficiency ε is calculated (step S105), and the temperature efficiency ε and the operating frequency value of the compressor 1 are stored in the storage unit 122 as effective values (step S106). The refrigerant amount determination means 23 performs the processing of steps S103 to S106 for a predetermined number of times (for example, 10 times) at a predetermined period during a predetermined time (for example, 10 minutes).

Subsequently, the refrigerant amount determination means 23 determines whether or not the plurality of temperature efficiencies ε stored in the storage unit 122 satisfy the calculation condition of the average temperature efficiency εAve (step S107). When the plurality of temperature efficiencies ε stored in the storage unit 122 do not satisfy the stability determination condition, the refrigerant amount determination unit 23 does not determine whether or not there is a refrigerant leak, and returns to step S102. The stability determination condition is, for example, that fluctuations of a plurality of temperature efficiencies ε from which the average temperature efficiency εAve is calculated are within a predetermined range. The stability determination condition may include a condition that fluctuations in the operating frequency of the compressor 1 stored in the storage unit 122 together with a plurality of temperature efficiencies ε are within a predetermined range.

On the other hand, as a result of the determination in step S107, when the plurality of temperature efficiencies ε stored in the storage unit 122 satisfy the stability determination condition, the refrigerant amount determination means 23 uses the values of the plurality of temperature efficiencies ε to calculate the average temperature efficiency. εAve is calculated (step S108). And the refrigerant | coolant amount determination means 23 compares the calculated average temperature efficiency (epsilon) Ave with threshold value (epsilon) Line, and determines whether average temperature efficiency (epsilon) Ave is more than threshold value (epsilon) Line (step S109).

If the result of determination in step S109 is that the average temperature efficiency εAve is equal to or greater than the threshold value εLine, the refrigerant amount determination means 23 resets the value of the variable M to zero if the variable M is not zero (step S110), and then the refrigerant The display unit 21 displays that the amount is normal (step S111). As a result of the determination in step S109, when the average temperature efficiency εAve is equal to or greater than the threshold value εLine and the value of the variable M is zero, the refrigerant amount determination unit 23 proceeds to step S111 without executing step S110. . As a result of the determination in step S109, when the average temperature efficiency εAve is smaller than the threshold value εLine, the refrigerant amount determination unit 23 determines that there is a refrigerant leak (step S200). And the refrigerant | coolant amount determination means 23 adds 1 to the value of the variable M (step S201), and determines whether the value of the variable M after adding 1 corresponds with N (step S202).

If the value of the variable M coincides with N as a result of the determination in step S202, the refrigerant amount determination means 23 displays on the display unit 21 that the refrigerant amount is insufficient (step S203). If the value of the variable M does not match N as a result of the determination in step S202, the refrigerant amount determination means 23 returns to step S102.

In this way, the refrigerant amount determination means 23 determines that the refrigerant amount is insufficient when the determination that there is a refrigerant leak is performed N times in succession, and displays that the refrigerant amount is insufficient. This is displayed on the unit 21. The refrigerant amount determination means 23 instructs the refrigeration cycle control means 22 to stop the refrigeration cycle operation.

(Procedure of the refrigerant shortage determination method in the first embodiment)
Next, the procedure of the refrigerant shortage determination method executed by the refrigeration apparatus in Embodiment 1 will be described. The refrigerant shortage determination method according to the first embodiment determines the refrigerant shortage at an early stage by determining that the refrigerant amount is insufficient at the stage where the sign of the refrigerant amount shortage is detected other than the decrease in temperature efficiency ε. It is something to detect.

FIG. 9 is a flowchart showing an operation procedure of the refrigerant shortage determination method executed by the refrigeration apparatus in Embodiment 1 of the present invention. Note that the processing in steps S101 to S111 shown in FIG. 9 is the same as that in steps S101 to S111 described with reference to FIG.

As a result of the determination in step S109 shown in FIG. 9, when the average temperature efficiency εAve is smaller than the threshold value εLine, the auxiliary determination unit 24 sets the discharge gas temperature of the compressor 1 and the parameters related to the discharge gas temperature for each parameter. It is determined whether or not the value deviates from each predetermined range (step S199).

As a result of the determination in step S199, the auxiliary determination unit 24 determines that at least one of the parameters related to the discharge gas temperature and the discharge gas temperature of the compressor 1 deviates from a predetermined range. It is determined that the amount of refrigerant is insufficient, and a message indicating that the amount of refrigerant is insufficient is displayed on the display unit 21 (step S203). In addition, the auxiliary determination unit 24 instructs the refrigeration cycle control unit 22 to stop the operation of the refrigeration cycle.

On the other hand, as a result of the determination in step S199, the auxiliary determination unit 24 determines the refrigerant amount when both the temperature of the discharge gas of the compressor 1 and the parameter related to the temperature of the discharge gas are within a predetermined range. The means 23 is notified that the refrigerant amount shortage has not been detected, and the processing of step S200 is instructed. When the refrigerant amount determination unit 23 receives an instruction for the process of step S200 from the auxiliary determination unit 24, the refrigerant amount determination unit 23 performs the process after step S200 as described with reference to FIG.

As described with reference to FIG. 9, every time the refrigerant amount determination unit 23 determines that the average temperature efficiency εAve is smaller than the threshold value εLine, the auxiliary determination unit 24 detects the temperature of the discharge gas and the discharge gas of the compressor 1. It is determined whether or not the amount of refrigerant is insufficient using a parameter related to temperature. Therefore, if the auxiliary determination unit 24 detects the refrigerant shortage earlier than the period in which the refrigerant amount determination unit 23 continuously determines the refrigerant leakage N times, the refrigeration apparatus stops the refrigeration cycle before the period elapses. And it can prevent that the compressor 1 breaks down.

In the first embodiment, the refrigeration apparatus shown in FIGS. 1A to 1C is taken as an example to describe the parameters for detecting the sign of insufficient refrigerant amount. However, the parameters corresponding to the configuration added to the refrigeration apparatus are described. May be added. 1A to 1C show the configuration in which the intake gas temperature sensor 52 is provided in the refrigeration apparatus, the intake gas temperature sensor 52 is refrigerated in accordance with the parameters used by the auxiliary determination means 24 for refrigerant shortage determination. It may not be provided in the apparatus.

The refrigeration apparatus of the first embodiment includes a refrigeration cycle in a refrigerant circuit that circulates refrigerant through the compressor 1, the heat source side heat exchanger 3, the supercooling heat exchanger 5, the load side expansion device 6, and the load side heat exchanger 7. Monitoring the temperature efficiency of the refrigerating cycle control means 22 for controlling the temperature and the supercooling heat exchanger 5, and if the temperature efficiency is equal to or greater than a predetermined threshold, it is determined that the amount of refrigerant charged in the refrigerant circuit is normal, When the temperature efficiency is less than the threshold value, the refrigerant amount determination means 23 for determining that there is a refrigerant leak and the parameter related to the temperature of the discharge gas of the compressor 1 when the refrigerant amount determination means 23 determines that there is a refrigerant leak The auxiliary determination means 24 determines whether or not the value deviates from a predetermined range, and determines that the amount of refrigerant is insufficient when the parameter value deviates from the range.
According to the first embodiment, when the refrigerant amount determination unit 23 determines that there is a refrigerant leak using the temperature efficiency of the subcooling heat exchanger 5 as a criterion for determining whether the refrigerant amount is appropriate, the auxiliary determination unit 24 uses the compressor. It is determined whether or not a parameter relating to the temperature of one discharge gas deviates from a predetermined range, and when the parameter value deviates from a predetermined range, the refrigerant amount is insufficient. judge. Therefore, in the refrigeration apparatus, before the refrigerant amount determination unit 23 detects the refrigerant shortage using the temperature efficiency, the auxiliary determination unit 24 can detect the occurrence of the refrigerant shortage, and the compressor 1 stops due to the abnormal temperature of the discharge gas. This can prevent the compressor 1 from failing.

In the first embodiment, the parameter related to the temperature of the discharge gas of the compressor 1 may be any one of the superheat degree of the suction port of the compressor 1 and the pressure of the refrigerant of the load side heat exchanger 7. An increase in the degree of superheat at the suction port of the compressor 1 increases the temperature of the discharge gas from the compressor 1, and a decrease in the refrigerant pressure in the load-side heat exchanger 7 increases the temperature of the discharge gas from the compressor 1. Therefore, the refrigerant shortage can be detected even if any of these parameters is used as the criterion for the refrigerant shortage.

Embodiment 2. FIG.
The second embodiment is a case where an injection circuit is provided in the refrigeration apparatus. The configuration of the refrigeration apparatus of the second embodiment will be described. In the second embodiment, detailed description of the same configuration as that described in the first embodiment is omitted.

FIG. 10 is a refrigerant circuit diagram illustrating a configuration example of the refrigeration apparatus according to Embodiment 2 of the present invention. 10 illustrates a case where the injection circuit is provided in the refrigeration apparatus illustrated in FIG. 1A, the refrigeration apparatus provided with the injection circuit is not limited to the refrigeration apparatus illustrated in FIG. 1A. The refrigeration apparatus provided with the injection circuit may be a refrigeration apparatus other than the configuration shown in FIG. 1A as described in the first embodiment.

As shown in FIG. 10, the refrigeration apparatus includes a pipe 41 branched from the refrigerant circuit on the outlet side of the supercooling heat exchanger 5 and connected to the intermediate port of the compressor 1, and an injection connected in series to the pipe 41. It has an injection circuit including an expansion device 42 and an accumulator 43. The intermediate port of the compressor 1 is an input port for injecting the refrigerant from the refrigerant circuit to the compressor 1 via the injection circuit on the outlet side of the supercooling heat exchanger 5. The injection expansion device 42 is, for example, an expansion valve.

The injection circuit injects refrigerant from the refrigerant circuit on the outlet side of the supercooling heat exchanger 5 into the intermediate port of the compressor 1 in order to cool the refrigerant of the compressor 1. The injection expansion device 42 adjusts the pressure of the refrigerant that is injected into the compressor 1 via the injection circuit. A temperature sensor 44 that detects the temperature of the refrigerant is provided at an intermediate port of the compressor 1. In the functional block diagram shown in FIG. 2, the control unit 20 is connected to each of the injection expansion device 42 and the temperature sensor 44 via signal lines (not shown).

In the case of the refrigeration apparatus shown in FIG. 10, the following two parameters can be considered as parameters related to the temperature of the discharge gas of the compressor 1. The first parameter is the temperature of the refrigerant input to the intermediate port of the compressor 1 via the injection circuit. This parameter is set as parameter P3. The second parameter is the opening degree of the injection expansion device 42 of the injection circuit. This parameter is set as parameter P4. In the case of the parameter P3, the fact that the temperature of the refrigerant input to the intermediate port of the compressor 1 is equal to or higher than the upper limit value in a predetermined range corresponds to the shortage of the refrigerant amount. In the case of the parameter P4, the fact that the opening of the injection expansion device 42 is equal to or greater than the upper limit value in a predetermined range corresponds to a shortage of the refrigerant amount.

FIG. 11 is a ph diagram for explaining an example of parameters for detecting a sign of a shortage of the refrigerant amount in the refrigeration apparatus shown in FIG. In FIG. 11, the vertical axis represents pressure [MPa] and the horizontal axis represents specific enthalpy [kJ / kg]. Of the four steps of the refrigeration cycle, point J1 → point J2 corresponds to the evaporation step, point J2 → point J3 corresponds to the compression step, point J3 → point J4 corresponds to the condensation step, and point J4 → point J1 This corresponds to the expansion process.

10, the refrigerant injected into the intermediate port of the compressor 1 via the injection circuit cools the compressor 1. Therefore, the compression process follows the path of point J2 → point J5 → point J3 shown in FIG. The temperature at point J5 shown in FIG. 11 corresponds to the temperature of the refrigerant input to the intermediate port of the compressor 1. When the temperature of the refrigerant input to the intermediate port of the compressor 1 rises and the point J5 changes to the point J5 'as shown in FIG. 11, the point J3 changes to the point J3' as shown by the broken line. As a result, the temperature of the discharge gas of the compressor 1 also increases. The auxiliary determination unit 24 determines that the amount of refrigerant is insufficient when the temperature detected by the temperature sensor 44 is equal to or higher than the upper limit value in a predetermined range.

Further, when the amount of refrigerant circulating in the refrigerant circuit decreases and the discharge temperature of the compressor 1 rises, the refrigeration cycle control means 22 increases the opening of the injection expansion device 42 in order to cool the refrigerant in the compressor 1. To do. The auxiliary determination means 24 determines that the amount of refrigerant is insufficient when the opening of the injection expansion device 42 is equal to or greater than the upper limit of a predetermined range.

In a refrigeration apparatus having an injection circuit, a parameter corresponding to the injection circuit is added as a parameter for detecting a sign of insufficient refrigerant amount. Therefore, the auxiliary determination means 24 can detect a sign of a shortage of the refrigerant amount due to the injection circuit.

Although FIG. 10 shows a configuration in which the temperature sensor 44 is provided in the refrigeration apparatus, the temperature sensor 44 may not be provided corresponding to the parameter used by the auxiliary determination unit 24 for the refrigerant shortage determination. Furthermore, the accumulator 43 may not be provided in the refrigeration apparatus shown in FIG.

The second embodiment is provided with an injection circuit that branches from the refrigerant circuit on the outlet side of the supercooling heat exchanger 5 and is connected to the compressor 1 and injects refrigerant from the refrigerant circuit into the compressor 1. Is provided with an injection expansion device 42 for adjusting the pressure of the refrigerant injected into the compressor 1. Therefore, any one of the temperature of the refrigerant injected into the compressor 1 through the injection circuit and the opening degree of the injection expansion device 42 can be used as a parameter related to the temperature of the discharge gas of the compressor 1. . Corresponding to the injection circuit provided in the refrigeration apparatus, the same effect as in the first embodiment can be obtained by selecting the parameter related to the temperature of the discharge gas of the compressor 1 and determining the presence or absence of refrigerant shortage. Can do.

1 compressor, 2 oil separator, 3 heat source side heat exchanger, 4 liquid receiver, 5 supercooling heat exchanger, 6 load side expansion device, 7 load side heat exchanger, 8 accumulator, 10 liquid extension pipe, 11 Gas extension pipe, 12-14, 41 pipe, 15 extension pipe, 20 control section, 21 display section, 22 refrigeration cycle control means, 23 refrigerant quantity judgment means, 24 auxiliary judgment means, 26, 27 fan, 42 injection expansion device, 43 accumulator, 44 temperature sensor, 51 discharge gas temperature sensor, 52 intake gas temperature sensor, 100 heat source side unit, 120 controller, 121 CPU, 122 storage unit, 150, 151 compression unit, 200 load side unit, 501, 502 arrow, ET evaporation temperature sensor, TH5 condensation temperature sensor, TH6 Outside air temperature sensor, TH8 liquid refrigerant temperature sensor.

Claims

A refrigerant circuit that circulates the refrigerant to the compressor, the heat source side heat exchanger, the supercooling heat exchanger, the load side expansion device, and the load side heat exchanger;
A control unit for controlling the refrigeration cycle in the refrigerant circuit,
The controller is
Refrigeration cycle control means for controlling the refrigeration cycle;
The temperature efficiency of the supercooling heat exchanger is monitored, and when the temperature efficiency is equal to or higher than a predetermined threshold, it is determined that the amount of refrigerant charged in the refrigerant circuit is normal, and the temperature efficiency is less than the threshold. If there is a refrigerant amount determining means for determining that there is a refrigerant leak,
When the refrigerant amount determining means determines that there is a refrigerant leak, it is determined whether or not a parameter value related to the temperature of the discharge gas of the compressor deviates from a predetermined range, and the parameter value is Auxiliary determination means for determining that the amount of refrigerant is insufficient when deviating from the range;
A refrigeration apparatus.
The refrigeration apparatus according to claim 1, wherein the parameter is any one of a superheat degree of an inlet of the compressor and a pressure of a refrigerant of the load side heat exchanger.
An injection circuit that branches from the refrigerant circuit on the outlet side of the supercooling heat exchanger and is connected to the compressor, and injects refrigerant from the refrigerant circuit into the compressor;
An injection expansion device that is provided in the injection circuit and adjusts the pressure of the refrigerant injected into the compressor;
The refrigeration apparatus according to claim 1, wherein the parameter is any one of a temperature of a refrigerant injected into the compressor via the injection circuit and an opening degree of the injection expansion device.