JP5063346B2 - Refrigeration and air conditioning system having refrigerant leakage detection function, refrigeration and air conditioning apparatus, and refrigerant leakage detection method - Google Patents

Description

  The present invention relates to a refrigeration and air conditioning system having a refrigerant leakage detection function, a refrigeration and air conditioning apparatus, and a method thereof.

  Various methods for detecting refrigerant leakage in refrigeration air conditioners have already been developed, and the following are known as refrigerant leakage detection methods for conventional refrigeration air conditioning devices, for example.

Some refrigerators determine that the refrigerant leaks when the refrigerant temperature difference at the inlet / outlet of the evaporator is larger than the reference temperature difference (see, for example, Patent Document 1). This refrigerant leakage determination is performed based on a temperature difference at one time point during operation.
In addition, there is a method of determining that the refrigerant is leaking when the refrigerant temperature is reduced by a temperature sensor attached to the header of the indoor unit heat exchanger when the compressor is stopped, exceeding a predetermined speed (see, for example, Patent Document 2). In this determination method, it is necessary to stop the compressor at the time of determination, so air conditioning operation cannot be performed during that time.
In addition, there is a method of determining by using a refrigerant sensor installed in the room, but the refrigerant gas detection sensor itself is expensive because it is special, and leakage cannot be detected unless the concentration of the leaked refrigerant in the air is some degree (for example, patent document) 3).
In addition, there is a method of judging by closing the solenoid valve during compressor operation and comparing the compressor drive current reduction rate at that time with a reference value, but it is possible to detect refrigerant leakage from solenoid valve to compressor inflow In the meantime, leakage between the compressor discharge and the electromagnetic valve cannot be detected, and the compressor is stopped at the time of determination, so the air conditioning operation cannot be performed during that time. (For example, refer to Patent Document 4).

JP 2005-90953 A Japanese Patent Laid-Open No. 2005-9857 JP 2004-69198 A JP 2004-36985 A

In the conventional method (Patent Document 1), the temperature difference at the inlet / outlet of the evaporator changes depending on the ambient temperature of the evaporator and the variation of the load. In addition, when there are a plurality of evaporators, the inlet / outlet temperature difference in each evaporator may be different, and it is difficult to accurately detect refrigerant leakage.
In the conventional method (Patent Document 2), for example, if R410A is used as the refrigerant and the circuit pressure at the time of determination is 2.0 MPa, a small amount of leakage such as a pressure drop rate of 0.02 MPa or less is detected per minute. There was a problem that I could not.
Further, even in the conventional method (Patent Document 3), since the data is a detection value at an instant at one moment, or the data of the decrease rate of the drive current that occurs in a short time of 1 minute as in Patent Document 4, it is long. It was not possible to detect a so-called slow leak in which the refrigerant gradually leaked over time. In addition, in order to detect refrigerant leakage, the conventional methods have hindered the operation of the apparatus.
Conventionally, the amount of refrigerant is judged from the viewpoint of preventing performance deterioration and compressor breakage, and it has been detected that the refrigerant has decreased at a fixed threshold regardless of the amount of refrigerant charged. When the refrigerant is overfilled in this state, it takes time to detect the amount of refrigerant, and there is a problem that the amount of refrigerant leaked before the detection is large and the influence on the environment becomes large.

ただし、kは凝縮器の番号、nは凝縮器の合計数、により算出されるものである。
The refrigerating and air-conditioning system of the present invention includes a compressor, an outdoor heat exchanger, and an outdoor unit having a throttle device, and one or a plurality of indoor units having an indoor heat exchanger and a throttle device, connected by a communication pipe for freezing. In the refrigerating and air-conditioning system constituting the cycle, there are a plurality of the outdoor heat exchanger or the indoor heat exchanger acting as a condenser, the past data relating to the past refrigerant amount of the refrigeration cycle, and the past time point Determining means for determining refrigerant leakage of the refrigeration cycle based on new data relating to the amount of refrigerant after the refrigeration cycle is stopped and started a plurality of times, and the determination means acts as a condenser The liquid phase area ratio that is the liquid phase volume ratio of the total volume of the outdoor heat exchanger or the indoor heat exchanger is calculated based on a plurality of parameters, and the calculated liquid phase area ratio is calculated in the past. Compared to historical data is intended to judge the refrigerant leak, the liquid phase area ratio A _L% is the degree of subcooling of the refrigerant in the condenser outlet SC, the difference between the outside air temperature and the condensing temperature dTc, the refrigerant The constant pressure liquid specific heat of Cpr is Cpr, the enthalpy difference between the condenser inlet and the condenser outlet is Δhcon, and the heat exchange capacity of each condenser is Q _j (k).

Here, k is a condenser number, and n is a total number of condensers.

  According to the refrigerating and air-conditioning system, the refrigerating and air-conditioning apparatus, and the refrigerant leakage detection method according to the present invention, it is possible to detect refrigerant leakage with a small amount of leakage per unit time while performing air-conditioning operation.

1 is a configuration diagram of a refrigeration air conditioner according to Embodiment 1. FIG. It is a flowchart which shows the refrigerant | coolant leak detection operation | movement with the apparatus of FIG. It is a block diagram of the refrigerating and air-conditioning apparatus according to Embodiment 2. It is the chart which showed the part added to the flowchart of FIG. 2, which shows the operation | movement peculiar to the refrigeration air conditioner of FIG. It is a block diagram of the refrigeration air conditioning apparatus which concerns on Embodiment 3. FIG. It is a flowchart which shows the refrigerant | coolant leak detection operation | movement with the apparatus of FIG. It is an illustration figure which shows the time change of the high / low pressure of the refrigerating cycle which concerns on Embodiment 3. FIG. It is a block diagram of the air conditioning system which concerns on Embodiment 4. FIG. 10 is a sequence diagram showing an operation of the air conditioning system according to Embodiment 4. It is a block diagram of the air conditioning system which concerns on Embodiment 5. FIG. FIG. 10 is a sequence diagram showing an operation of the air conditioning system according to Embodiment 5. It is a sequence diagram which shows operation | movement of the air conditioning system which concerns on Embodiment 6. FIG. 12 is a sequence diagram showing an operation of the air conditioning system according to Embodiment 7.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Outdoor heat exchanger, 4 Outdoor fan, 5 Throttle device, 6 Gas refrigerant piping, 7a, 7b Throttle device, 8a, 8b Indoor blower, 9a, 9b Indoor heat exchanger, 10 liquid refrigerant Piping, 11 Discharge temperature sensor, 12 Discharge pressure sensor 8 13 Outdoor temperature sensor, 14 Temperature sensor, 15a, 15b Temperature sensor, 16a, 16b Indoor unit suction temperature sensor, 17a, 17b Temperature sensor, 18 Suction temperature sensor, 19 Suction pressure Sensor 101 Measurement unit 102 Calculation unit 103 Control unit 104 Storage unit 105 Comparison unit 106 Determination unit 107 Notification unit 108 Calculation determination unit 100 Outdoor unit 110 Indoor unit 120 Centralized controller 130 Remote monitoring apparatus.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a refrigerant circuit configuration of a refrigeration air-conditioning apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a flowchart showing refrigerant leakage detection operation by the apparatus of FIG.

As shown in FIG. 1, this refrigeration air conditioner constitutes an refrigeration cycle including an outdoor unit and an outdoor unit. In the outdoor unit, a compressor 1, a four-way valve 2, which is a flow path switching device, an outdoor heat exchanger 3, and a throttling device 5 are connected in order to constitute a refrigerant main circuit. In addition, the expansion units 7a and 7b and the indoor heat exchangers 9a and 9b are connected to the indoor unit to constitute a refrigerant main circuit. The outdoor unit and the indoor unit are connected by a liquid refrigerant pipe 6 and a gas refrigerant pipe 10. The outdoor heat exchanger 3 is provided with a fan 4 for blowing air, and the indoor heat exchangers 9a and 9b are similarly provided with fans 8a and 8b for blowing air.
A discharge temperature sensor 11 for detecting the refrigerant temperature and a discharge pressure sensor 12 for measuring the pressure in the pipe are provided on the discharge side of the compressor 1. A suction temperature for detecting the temperature of the suction side refrigerant is provided on the suction side of the compressor 1. A sensor 18 and a suction pressure sensor 19 for measuring the pressure in the pipe are installed. An outdoor temperature sensor 13 for detecting the ambient air temperature of the outdoor unit and a temperature sensor 14 for detecting the refrigerant outlet (at the time of cooling) temperature of the outdoor heat exchanger 3 are provided.
Temperature sensors 15a, 15b, 17a, and 17b are provided at the refrigerant inlet / outlet of the indoor heat exchangers 9a and 9b, and the ambient air temperature in the room is detected by the indoor unit intake temperature sensors 16a and 16b.
Each temperature sensor is provided so as to be in contact with or inserted into the refrigerant pipe, and can detect the refrigerant temperature at that portion. Each throttle device is composed of a pressure regulating valve and the like.

  Each amount detected by each temperature sensor and each pressure sensor is input to a measurement unit 101 that aggregates measurement results, and is used for calculation processing in the calculation unit 102 as necessary. Based on the calculation result of the calculation unit 102, the compressor 1, the four-way valve 2, the fans 4, 8a, 8b, and the expansion devices 5, 7a, 7b are controlled, and the refrigeration cycle is controlled so as to be within a desired control target range. The control unit 103 is provided. The control unit 103 is connected to each device constituting the refrigeration cycle by wire or wireless, and can control each device. The control unit 103 also includes an operation confirmation unit that determines whether or not the indoor unit is in operation, an integration unit (or timer device) that integrates the operation time of the compressor 1, a time measurement unit that measures the date and time, and the like. I have. The refrigerating and air-conditioning apparatus has a storage unit 104 as storage means (or a storage device) that stores the results obtained by the calculation unit 102, predetermined constants, and the like. There is a comparison unit 105 that compares the predetermined value with the predetermined value. Furthermore, from the result of comparison in the comparison unit 105, the determination unit 106 for determining the refrigerant charging state of the refrigeration air-conditioning apparatus, and the determination result in the determination unit 106 are used as the indoor unit remote control, LED (light emitting diode) and / or remote location There is an informing unit 107 as an informing means for informing the monitor or the like. Here, the calculation unit 102, the storage unit 104, the comparison unit 105, and the determination unit 106 are collectively referred to as a calculation determination unit (or determination unit) 108. Note that the measurement unit 101, the control unit 103, the notification unit 107, and the calculation determination unit 108 are usually configured by a microcomputer, a personal computer, a CPU, a program, and the like.

  Although FIG. 1 shows a case where the indoor unit has two indoor heat exchangers, the number of indoor heat exchangers is not limited to this, and may be one or three or more. Moreover, the capacity | capacitance of each indoor heat exchanger may differ, and all may be the same capacity | capacitance. Further, a plurality of outdoor heat exchangers may be similarly connected.

Next, the operation operation by this refrigeration air conditioner will be described.
In the cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 reaches the outdoor heat exchanger 3 via the four-way valve 2 and is condensed (at this time, the outdoor heat exchanger 3 acts as a condenser). The condensation temperature at this time can be obtained as the saturation temperature of the pressure of the pressure sensor 12 attached to the discharge side of the compressor 1. Further, the degree of supercooling of the refrigerant at the outlet of the outdoor heat exchanger 3 is determined by the difference between the condensation temperature and the temperature sensor 14. The condensed refrigerant is reduced in pressure by the expansion devices 7a and 7b of the indoor units through the expansion device 5 and the liquid refrigerant pipe 6 of the outdoor unit with the full opening degree, and enters a two-phase state. The refrigerant that has exited the expansion devices 7a and 7b evaporates in the indoor heat exchangers 9a and 9b (at this time, the indoor heat exchangers 9a and 9b function as evaporators). Thereafter, the refrigerant returns to the compressor 1 via the gas refrigerant pipe 10 and the four-way valve 2. The degree of superheat of the refrigerant at the outlet of the outdoor heat exchanger 3 is determined by the difference between the temperature sensors 17a and 15a or the difference between 17b and 15b.

  In the heating operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 reaches the indoor heat exchangers 9a and 9b via the four-way valve 2 and the gas refrigerant pipe 10 and is condensed (at this time, the indoor heat exchanger 9a, 9b acts as a condenser). The condensation temperature at this time can be obtained as the saturation temperature of the pressure of the pressure sensor 12 attached to the discharge side of the compressor 1. Moreover, the supercooling degree of the refrigerant | coolant in each indoor heat exchanger 9a, 9b exit is calculated | required as a difference of each condensation temperature and temperature sensor 15a, 15b. The condensed refrigerant is decompressed by the expansion device 5 of the outdoor unit via the expansion devices 15a and 15b and the liquid refrigerant pipe 6 of the indoor unit with the fully opened opening, and becomes a two-phase state. The refrigerant exiting the expansion device 5 evaporates in the outdoor heat exchanger 3 (at this time, the outdoor heat exchanger 3 acts as an evaporator). Thereafter, the refrigerant returns to the compressor 1 via the four-way valve 2. The degree of superheat of the refrigerant at the outlets of the indoor heat exchangers 9a and 9b is obtained as a difference between the temperature sensor 18 and the temperature sensor 14.

Next, cooling / heating leakage detection by the refrigeration air conditioner will be described.
Add refrigerant when installing new pipes and installing indoor units and outdoor units, or when replacing existing indoor units and outdoor units with new indoor units and outdoor units by reusing existing pipes installed in buildings. When the refrigerant amount is intentionally changed during installation work or maintenance, such as when it is filled, the calculation determination unit 108 stores the refrigerant amount (or operation status data) at that time in advance as an initial value of the enclosed refrigerant. deep. That is, at the time of trial operation immediately after installation of the refrigeration air conditioner, the calculation determination unit 108 performs refrigerant amount determination, and the calculation unit 102 calculates the result (AL% value, temperature, etc. described later). Remember. The determination of the initial value can also be performed during normal operation, but during the trial operation, the installer can set conditions without being influenced by the user's usage status, so it is easy to create conditions suitable for determining the refrigerant amount.
In addition, during the execution of the detection of the cooling / heating leak detection, it is preferable to display a display such as “running refrigerant leak detection operation” or “running refrigerant amount judgment operation” on the remote controller or display of the indoor unit. . This is because it becomes easier for the user of the air conditioner or the maintenance company to grasp the operating state of the air conditioner.

Here, a specific example of the cooling / heating leakage detection operation based on the measurement, control, and determination functions of the measurement unit 101, the control unit 103, and the calculation determination unit 108 will be described with reference to the flowchart of FIG.
During cooling or heating operation, it is determined whether the time (integrated operation time) since the previous refrigerant leakage determination of the compressor 1 has passed a predetermined time (for example, 100 hours) (step S1) If it has elapsed, the process proceeds to the next step, and if it has not elapsed, the process returns to the normal air conditioning operation.
For the measurement of the accumulated operation time, the time during which the control unit 103 (accumulation means) issues an operation command (outputs the command frequency) to the compressor 1 is stored in the memory as the accumulated time every 1 hour, for example. To execute. Also, a current sensor is provided in the compressor wiring instead of the time when the operation command is issued, and this current sensor detects the time during which the current is flowing in the compressor driving wiring, and the control unit 103 calculates the accumulated time. It can also be calculated.

  In addition, since the possibility of refrigerant leakage due to brazing failure or the like is high immediately after air conditioner construction or component replacement, it is preferable to frequently perform refrigerant leakage determination at time intervals shorter than the above time.

Further, instead of the accumulated operation time of the compressor 1 in step S1, a time measuring means (year / month / day / time output function) may be built in, and the refrigerant leakage determination may be performed at a predetermined date and time. As the time measuring means, a known timer circuit or the like can be used. The control unit 103 resets the timer circuit when the refrigeration air conditioner is installed, and the timer measures the elapsed time since the installation. The control unit 103 acquires time information from the timer regularly or irregularly, and determines whether a predetermined set time has elapsed. Thereby, even when the air-conditioning operation is not performed for a long time, the refrigerant leakage determination is executed and the leakage of the refrigerant can be detected. In addition, when the refrigerant leakage detection is performed at one end as described above, the control unit 103 performs the next leakage detection at a predetermined timing by resetting the timer circuit or newly resetting the set time. Prepare.
Here, for example, if leakage detection is performed in the middle of spring and autumn (twice a year), it can be determined under conditions where the outside air temperature is close. As a result, the pressure and temperature of the refrigerant when the air conditioner is operating become substantially constant at each judgment timing, and the density of the refrigerant in each part of the refrigerant pipe becomes almost constant at the judgment timing. It is possible to reduce the error caused by the difference and perform the determination with high accuracy.

Although not included in the flow of FIG. 2, the control unit 103 determines the outdoor temperature information detected by the outdoor temperature sensor 13 after the end of step S1, and the outdoor temperature is within a predetermined range (for example, ± The refrigerant leakage determination may be performed only at 5 ° C. For example, the control unit 103 stores the outside air temperature at the time of the previous refrigerant amount determination such as a trial operation in the storage unit 104 or another memory, and the difference between the outside air temperature and the current outside air temperature is within a predetermined range (± 5 (Centigrade), refrigerant leakage judgment is performed. If the difference in the outside air temperature is equal to or greater than the predetermined range, the process waits until the outside air temperature falls within the predetermined range before proceeding to refrigerant leakage determination. By doing so, the pressure and temperature of the refrigerant when the refrigeration air conditioner is operating become substantially constant at each determination timing, and the density of the refrigerant in each part of the refrigerant pipe becomes almost constant at the determination timing. It is possible to reduce the error caused by the difference in the density and to perform the determination with high accuracy.
When the outside air temperature difference does not fall within the predetermined range, a correction value of a determination parameter (for example, AL% described later) for determining the refrigerant leakage is determined in accordance with the outside air temperature difference, and the control unit 103 It is also possible to perform refrigerant leakage determination by correcting the determination parameter. The correction value is obtained in advance by measurement corresponding to the outside air temperature difference and stored in a memory or the like, or is determined by the control unit 103 by calculation as a function of the outside air temperature difference or the outside air temperature. The refrigerant amount leakage detection by this correction may be performed when the outside air temperature does not fall within the predetermined range after waiting for a predetermined time, or may be performed without waiting.

Subsequently, the stability of the operation on the refrigeration cycle is determined (step S2). This determination is performed by determining whether the change value of the physical quantity on the refrigeration cycle determined in advance by the control unit 103 is within a predetermined range. The control unit 103 uses a temperature sensor or a pressure sensor as physical quantity detection means to determine whether or not the amount of change in the refrigerant temperature or pressure within a predetermined time is equal to or less than a predetermined amount. For example, the control unit 103 monitors the detected temperature of the discharge temperature sensor 11 and determines that the refrigeration cycle is stable when the difference between the upper limit value and the lower limit value for 3 minutes is within 2 ° C. The control unit 103 monitors the detection value of the pressure sensor provided in the discharge pipe or the suction pipe of the compressor 1 as a stability determination parameter, and the difference between the upper limit value and the lower limit value of the detection value for 3 minutes is 1 kgf. It can also be determined that the current is stable at / cm ² . It is desirable that these condition values are determined to be appropriate values by performing a test in advance and taking into account the allowable value of the refrigerant amount determination error. In addition, it is judged whether the refrigeration cycle is stable based on the stability of the frequency of the compressor 1, the opening degree of the expansion devices 5, 7a, 7b, the degree of supercooling at the outlet of each heat exchanger 3, 9a, 9b, the degree of superheating, etc. May be. If the refrigeration cycle is unstable, refrigerant leakage cannot be detected accurately, so the process proceeds to the next step only when it is determined that the refrigeration cycle state is stable. Return.

  In addition, since the refrigerant amount staying in the stopped indoor heat exchangers 9a and 9b is difficult to estimate from the temperature sensor or the like at the time of refrigerant leakage determination, there are stopped indoor heat exchangers 9a and 9b. If the refrigerant leakage determination is performed in the state, the determination accuracy decreases. For this reason, in order to accurately determine the refrigerant leakage, the control unit 103 determines whether or not all of the connected indoor heat exchangers 9a and 9b are in the cooling operation or the heating operation. When the operation or all the units are in the heating operation, the process proceeds to the next step (step S3). When all the indoor heat exchangers are not operated, the entire number is operated and then the process proceeds to the next step (step S3 ′). In addition, when not operating all, you may make it hold | maintain determination and return to a normal air-conditioning driving | operation.

  In addition, when the refrigerant leak determination operation has a smaller influence on the performance and the like than the normal operation, and the total number of indoor heat exchangers is the cooling operation or the total number is the heating operation, the operation integration of the compressor 1 is performed. Regardless of the time or date, the refrigerant leakage determination may always be performed.

  Subsequently, the control unit 103 uses the expansion device at the evaporator inlet (the expansion devices 7a and 7b correspond to the cooling time and the expansion device 5 corresponds to the heating time), so that the refrigerant superheat degree at the evaporator outlet exceeds a predetermined value. Control is performed (step S4). As a result, the liquid refrigerant does not stay in the gas refrigerant pipe 10 and the liquid refrigerant is stored only in the liquid refrigerant pipe 6 and the condenser, and the determination is performed using the liquid phase area ratio AL% of the condenser as an index. it can.

Subsequently, the operation determination unit 108 determines whether the refrigerant amount is appropriate (steps S5 and S6). The determination is made by the following formula (1)
AL% =-Ln (1-SC / dTc) x dTc x Cpr / △ hcon (1)
Using the calculation unit 102 to perform calculation processing, the comparison unit 105 compares the result with the past calculation result AL% recorded as history data, and the determination unit 106 determines the refrigerant leakage based on the comparison result. I do. AL% is the liquid phase volume ratio of the total volume of the condenser, and is an index obtained by correcting the refrigerant supercooling degree of the condenser by the outside air temperature, the discharge enthalpy of the compressor, and the low pressure liquid specific heat of the refrigerant.
Here, SC is the degree of supercooling of the refrigerant at the condenser outlet, dTc is the difference between the outside air temperature and the condensation temperature, Cpr is the constant-pressure liquid specific heat of the refrigerant, and Δhcon is the enthalpy difference between the condenser inlet and the condenser outlet. In addition, when there are a plurality of condensers, AL% in each condenser is calculated, and refrigerant leakage is determined based on the calculation result of the following equation (2) calculated by weighted average according to the capacity.

ここで、Q_j(k)は各凝縮器の熱交換容量を表し（例えば28kWなどの空調能力）、kは凝縮器の番号であり、ｎは凝縮器の合計数である。冷房の場合は室外熱交換器が凝縮器となり、暖房の場合は室内熱交換器が凝縮器となる。図１の構成例では室内熱交換器９ａ、９ｂが複数であり、暖房時に式（２）を適用することになる。また、室外熱交換器が複数接続される回路構成の場合には、冷房運転で凝縮器が複数存在することになるため、この場合にも式（２）でAL%を計算する。

Here, Q _j (k) represents the heat exchange capacity of each condenser (for example, air conditioning capacity such as 28 kW), k is the number of the condenser, and n is the total number of condensers. In the case of cooling, the outdoor heat exchanger becomes a condenser, and in the case of heating, the indoor heat exchanger becomes a condenser. In the configuration example of FIG. 1, there are a plurality of indoor heat exchangers 9a and 9b, and the formula (2) is applied during heating. In the case of a circuit configuration in which a plurality of outdoor heat exchangers are connected, a plurality of condensers are present in the cooling operation. In this case as well, AL% is calculated using equation (2).

  If the amount of refrigerant is insufficient, the degree of supercooling at the outlet of the condenser cannot be achieved, and the AL% value becomes low. Accordingly, the determination unit 106 determines that the refrigerant is insufficient if the AL% value is smaller than the value at the time of trial operation (or the initial value immediately after charging the refrigerant), and displays from the notification unit 107 a display device such as an indoor unit remote controller or an outdoor unit LED. The control unit 103 receives the determination result indicating the abnormality of the determination unit 106 and stops the operation of the refrigeration cycle (step S8). On the other hand, if AL% is equal to or greater than the value at the time of trial operation or a predetermined value, the determination unit 106 determines that the refrigerant amount is within an appropriate range, and the control unit 103 receives the determination result and the operation unit of the compressor 1 is integrated. After resetting the time (step S6 ′), the routine proceeds to normal air conditioning operation. That is, the operation state before the determination is returned.

  In the test operation, the refrigerant leakage is determined by comparing with an appropriate AL% value determined in advance by a test or the like.

  The refrigerant leakage determination described above is not a single operating state quantity such as the degree of superheat or supercooling of the refrigeration air conditioner, but the amount of refrigerant in the refrigerant circuit by calculating the liquid phase area ratio of the condenser based on a plurality of parameters. Therefore, stable accuracy can be obtained even when environmental conditions such as the outside air temperature change. In addition, by calculating the weighted average of the liquid phase area ratio according to the number and capacity of the condensers, it is possible to determine the exact amount of refrigerant in the circuit even when there are multiple condensers with different capacities. This makes it possible to accurately detect refrigerant leakage.

  Further, in the refrigeration and air-conditioning apparatus of this embodiment, the refrigerant leakage is detected by calculating the refrigerant amount in the entire circuit, so the determination accuracy does not depend on the refrigerant leakage speed, and leaks little by little. It is possible to detect even if there is. In addition, by determining the amount of refrigerant when the operation mode of the refrigeration cycle, the outside air temperature, and the operation state of the indoor unit are similar, the amount of refrigerant can be determined each time at a timing when the pressure and temperature of the refrigerant are close, The density of the refrigerant in the refrigerant pipe is almost constant, there is little estimation error, and the determination accuracy can be improved.

Moreover, in the refrigerating and air-conditioning apparatus according to this embodiment, since the determination is performed using only the temperature sensor and the pressure sensor without using a special sensor or the like, the refrigerant leakage can be detected at a low cost. In addition, since the physical quantity (reference quantity) for judging the stability of the refrigeration cycle is the temperature, pressure of the refrigeration cycle, or the degree of supercooling and superheat of the refrigerant calculated from them, the judgment timing is stable with an inexpensive configuration. Judgment is possible.
Furthermore, in the refrigerating and air-conditioning apparatus according to this embodiment, refrigerant leakage detection is possible while performing air conditioning operation for cooling or heating.

Note that steps S1 to S3 shown in FIG. 2 have the same effect even if the order is changed. In this embodiment, the index of AL% is used for the determination of the refrigerant amount. For example, the supercooling degree of the refrigerant at the condenser outlet during operation, the superheat degree of the refrigerant at the evaporator outlet, the refrigerant discharged from the compressor Preliminarily understand the correlation between the refrigerant quantity such as temperature and the refrigerant quantity, and read the change in the parameter related to the refrigerant quantity at the above judgment timing, detect the refrigerant quantity, and judge the refrigerant leakage. May be. In addition, a reservoir is provided at the outlet of the condenser or the outlet of the evaporator, and means for determining the amount of liquid inside the reservoir based on the liquid level inside the reservoir is provided, and the amount of refrigerant is determined at the above determination timing. Then, the refrigerant amount may be detected and the refrigerant leakage may be determined. The determination using the liquid reservoir will be described in detail in the third embodiment.
In addition, the arithmetic determination unit 108 determines the initial value of the refrigerant when the refrigeration air conditioner is trial run. If the refrigerant amount does not change, that is, in the initial stage after charging, the operation determination unit 108 performs normal operation. Sometimes it can be determined. Further, the determination may be performed at any timing as long as the refrigerant amount does not change. For example, it can be determined when the compressor integration time is 10 hours or less during normal operation and the measurement conditions (conditions such as the above-described all indoor unit operation and refrigeration cycle stability) are met.

Embodiment 2. FIG.
FIG. 3 is a diagram showing a refrigerant circuit configuration of a refrigeration air conditioner according to Embodiment 2 of the present invention, and FIG. 4 shows a part added to the flowchart of FIG. It is a chart.
As shown in FIG. 3, this refrigeration air conditioner is different from the refrigeration air conditioner of FIG. 1 in that an accumulator 20 is provided on the compressor suction side. A temperature sensor 21 for measuring the refrigerant temperature is installed at the outlet of the accumulator 20.

In the case of the refrigerating and air-conditioning apparatus as shown in FIG. 3, it is difficult to estimate the amount of refrigerant remaining in the accumulator 20, so it is necessary to prevent liquid refrigerant from staying in the accumulator 20 when determining refrigerant leakage. For this reason, the throttle device at the evaporator inlet is controlled so that the degree of refrigerant superheat at the evaporator outlet can be sufficiently obtained (step S4 in FIG. 4).
When the liquid refrigerant stays in the accumulator 20, when the refrigerant gas sufficiently heated by the throttle device at the evaporator inlet flows into the accumulator 20, it is cooled by the liquid refrigerant in the accumulator 20, and the outlet temperature of the accumulator 20 is the inlet temperature. Lower than. Thus, when the inlet temperature of the accumulator 20> the outlet temperature of the accumulator 20, it is determined that the liquid refrigerant is staying in the accumulator 20 (step S4 ′ in FIG. 4), and the refrigerant leakage determination is not performed. On the other hand, if the inlet temperature of the accumulator 20 <the outlet temperature of the accumulator 20, it is determined that the liquid refrigerant has not accumulated in the accumulator 20 (step S4 ′ in FIG. 4), and refrigerant leakage determination is performed ( Step S5) in FIG. Steps S4 and S5 shown in FIG. 4 correspond to those in FIG.

  Note that, when the liquid refrigerant stays in the accumulator 20, the suction superheat degree and the discharge superheat degree of the compressor 1 become low. By utilizing this, whether or not the liquid refrigerant is accumulated in the accumulator 20 depending on the temperature of the refrigerant superheat on the suction side and the discharge side of the compressor 1 without installing the temperature sensor 21 at the outlet of the accumulator 20. It may be judged.

  In addition, when the operation is performed with a sufficient degree of superheat at the outlet of the evaporator, the liquid refrigerant in the accumulator 20 gradually evaporates. Therefore, the elapsed time of the operation with a sufficient degree of superheat at the outlet of the evaporator. May be used to determine whether or not the liquid refrigerant is retained in the accumulator 20.

  In the refrigerating and air-conditioning apparatus having the accumulator 20 in the refrigerant circuit as described above, it is determined whether or not the liquid refrigerant stays in the accumulator 20, and only when the liquid refrigerant does not stay there, the refrigerant amount Therefore, the refrigerant leakage detection is performed and the refrigerant leakage detection accuracy is improved.

Embodiment 3 FIG.
Here, the determination of the refrigerant amount using the liquid reservoir and the refrigerant leakage detection using the refrigerant amount will be described. FIG. 5 is a diagram illustrating a refrigerant circuit configuration of a refrigeration air-conditioning apparatus according to Embodiment 3 of the present invention. In FIG. 5, the same components as those in FIG. 3 of the second embodiment are denoted by the same reference numerals, and hereinafter, differences from FIG. 3 will be mainly described.
The refrigerating and air-conditioning apparatus of FIG. 5 is connected in series with the liquid reservoir 28 for storing the refrigerant liquid connected between the expansion device 5 of the outdoor unit and the liquid refrigerant pipe 6, and supercools the refrigerant. The refrigerant heat exchanger 30 is provided. In addition, one end of the refrigerant heat exchanger 30 is connected to a refrigerant pipe between the refrigerant heat exchanger 30 and the liquid refrigerant pipe 6 via the subcooling bypass expansion device 26, and the other end is an inlet pipe of the accumulator 20. Connected. A bypass pipe connected to a low-pressure portion such as an inlet of the accumulator 20 is connected to the upper part of the liquid reservoir 28 via refrigerant amount determination throttle devices 25a and 25b. The bypass pipe is for detecting the liquid level of the liquid reservoir 28. Here, the two bypass pipes are arranged inside the liquid reservoir 28 with a predetermined height difference. The number of bypass pipes for detecting the liquid level taken out from the liquid reservoir 28 is not limited to two, and the number may be appropriately increased or decreased according to the level to be determined.
In FIG. 5, reference numerals 27 a and 27 b are liquid level detection temperature sensors provided in the bypass pipe, and 31 is a subcooling detection temperature provided between the refrigerant heat exchanger 30 and the liquid refrigerant pipe 6. A sensor 32 is a temperature sensor for the bypass circuit provided in the bypass circuit.
Reference numerals 33a and 33b are refrigerant heating means used when detecting the liquid level of the liquid reservoir 28. The refrigerant heating means may use an external heat source such as an electric heater, or a refrigerant such as hot gas. You may employ | adopt the heating mechanism made to contact with the high temperature part on a circuit.

  Next, a method for detecting the initial liquid level in the liquid reservoir during the cooling operation in the refrigeration air conditioner of FIG. 5 will be described. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed and liquefied by the outdoor heat exchanger 3, and is slightly squeezed by the expansion device 5 and then flows into the liquid reservoir 28. When the liquid level rises in the liquid reservoir 28 and the liquid reservoir 28 is almost full, the liquid refrigerant flows into the refrigerant heat exchanger 30 and the refrigerant amount determination expansion device 25a is opened to determine the refrigerant amount. The refrigerant also flows through the bypass piping through the expansion device 25a. The liquid refrigerant that has flowed into the refrigerant heat exchanger 30 exchanges heat with the gas-liquid two-phase refrigerant that has been bypassed from the liquid refrigerant pipe 6 and has become low temperature via the subcooling bypass expansion device 26 in the refrigerant heat exchanger 30. The degree of supercooling is increased and the heat exchanger enters the indoor heat exchangers 9a and 9b. The refrigerant evaporates and evaporates in the indoor heat exchangers 9a and 9b and is used for cooling, and the gasified refrigerant returns to the compressor 1 via the gas refrigerant pipe 10, the four-way valve 2, and the accumulator 20. In the indoor heat exchangers 9a and 9b, the degree of superheat of the refrigerant at the outlet of the indoor heat exchanger is determined by the difference between the temperature sensors 17a and 15a or the difference between 17b and 15b so that the refrigerant is completely evaporated. The flow rate is controlled by the expansion devices 7a and 7b of the indoor unit so that the degree of superheat becomes a predetermined value or more.

  On the other hand, the liquid refrigerant that has flowed out from the upper part of the full liquid reservoir 28 becomes a low-temperature gas-liquid two-phase refrigerant that has been squeezed to a low pressure by the refrigerant amount determination throttle device 25a, and is heated by the heating means 33a. The amount of heat in the heating means 33a is adjusted in advance to an amount of heat that evaporates only a part of the refrigerant liquid. By doing so, when the refrigerant flowing through the refrigerant amount determination throttle device 25a contains liquid, even if heated by the heating means 33a, only a part of the refrigerant evaporates. Even when it passes, the temperature of the refrigerant remains low. On the other hand, when the refrigerant flowing through the refrigerant amount determination throttling device 25a is completely gas only, when heated by the heating means 33a, the temperature of the refrigerant rises according to the amount of heating. By utilizing this, it is determined whether or not a sufficient amount of liquid has accumulated in the liquid reservoir 28 by detecting the temperature with a liquid level detecting temperature sensor 27a installed downstream of the heating means 33a. If the liquid level is not full, the refrigerant amount determination throttling device 25b is opened, the heating means 33b is used, and the temperature is detected by the liquid level detection temperature sensor 27b, so that the liquid reservoir 28 corresponds. It is determined whether there is liquid up to the lower end position of the bypass pipe.

  Next, a method for detecting the initial liquid level in the liquid reservoir during the heating operation in the refrigeration air conditioner of FIG. 5 will be described. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows through the gas refrigerant pipe 10, condenses and liquefies in the indoor heat exchangers 9 a and 9 b, is slightly squeezed by the expansion devices 15 a and 15 b, and then flows into the liquid reservoir 28. When the liquid level rises in the liquid reservoir 28 and the liquid reservoir 28 is almost full, the liquid refrigerant flowing out from the upper portion of the liquid reservoir is evaporated in the outdoor heat exchanger 3, and the vaporized refrigerant is the four-way valve 2, It returns to the compressor 1 through the accumulator 20. In the outdoor heat exchanger 3, the degree of superheat of the refrigerant at the outlet of the outdoor heat exchanger 3 is obtained by the difference between the temperature sensor 14 and the temperature sensor 32 so that the refrigerant is completely evaporated, and the degree of superheat is a predetermined value or more. Thus, the flow rate is controlled by the expansion device 5 of the outdoor unit.

On the other hand, the liquid refrigerant that has flowed out from the upper part of the full liquid reservoir 28 becomes a low-temperature gas-liquid two-phase refrigerant that has been squeezed to a low pressure by the refrigerant amount determination throttle device 25a, and is heated by the heating means 33a. The heating amount of the heating means 33a is adjusted in advance to an amount of heat that evaporates only a part of the refrigerant liquid. In this way, when the refrigerant flowing through the refrigerant amount determination throttle device 25a contains liquid, even if the refrigerant is superheated by the heating means 33a, only a part of the refrigerant evaporates. Even when it passes, the temperature of the refrigerant remains low. On the other hand, when the refrigerant flowing through the refrigerant amount determination throttling device 25a is completely gas only, when heated by the heating means 33a, the temperature of the refrigerant rises according to the amount of heating. By utilizing this, it is determined whether or not a sufficient amount of liquid has accumulated in the liquid reservoir 28 by detecting the temperature with the temperature sensor 27a for detecting the liquid level disposed downstream of the heating means 33a. If the liquid level is not full, the refrigerant amount determination throttling device 25b is opened, the heating means 33b is used, and the temperature is detected by the liquid level detection temperature sensor 27b, so that the liquid reservoir 28 corresponds. It is determined whether there is liquid up to the lower end position of the bypass pipe.
In this example, two bypass pipes are used to detect the liquid level of the liquid reservoir 28 in two stages. However, the liquid level may be detected in only one stage, or 3 It may be more than stages.

A method of determining the refrigerant amount in the refrigerant circuit by detecting the liquid level of the liquid reservoir 28 as described above and determining whether or not refrigerant leakage has occurred based on the refrigerant amount will be described. FIG. 6 is a flowchart showing an example of the refrigerant leakage detection operation in the refrigeration and air-conditioning apparatus of FIG. 5, and will be described along this flow.
After completion of the construction or replacement of the refrigeration air conditioner, a trial operation of the refrigeration air conditioner is performed in step S1. Here, the control unit 103 determines the operation of cooling or heating according to the outside air temperature, room temperature, or air conditioning load, sends a control signal to each device of the indoor unit and the outdoor unit, and activates the refrigeration air conditioner in the trial operation mode. , Control the driving. This determination may be performed automatically according to a predetermined criterion, or may be performed manually by an operator operating the refrigeration air conditioner. However, in a multi-type refrigerating and air-conditioning apparatus having a plurality of indoor units, the state of the stopped indoor heat exchanger becomes a liquid-sealed state or a gas state. Since the amount of liquid refrigerant that accumulates changes, all the plurality of indoor units (indoor heat exchangers) are operated from the viewpoint of keeping the state inside the indoor heat exchanger constant.

  The refrigerant amount is detected after waiting for the time until the liquid refrigerant is accumulated in the liquid reservoir 28 or the time until the high and low pressures of the refrigeration cycle are stabilized and the density of the refrigerant in the refrigerant pipe is stabilized. In the trial operation, as shown in FIG. 7, the high pressure and low pressure movements after startup once overshoot or undershoot the target value, and then stabilize toward the target value. For this reason, the reference for determining that the operation of the refrigeration cycle is stable is, for example, the time until the change width of the refrigerant pressure, temperature, degree of superheat, degree of supercooling, etc. falls within a predetermined value.

In step S2, the control unit 103 controls the refrigerant amount determination throttle devices 25a and 25b to open the throttle. Next, the measurement unit 101 reads the temperature detection signals of the liquid level detection temperature sensors 27a and 27b.
Subsequently, the control unit 103 stores the test operation state in the storage unit 104. The contents stored at this time include the detection temperature of each of the liquid level detection temperature sensors 27a and 27b (the liquid level of the liquid reservoir 28), the cooling or heating operation mode, the high pressure of the refrigerant, the low pressure of the refrigerant, and the discharge of the compressor. The operation state such as temperature, condenser outlet supercooling degree, evaporator outlet evaporation temperature, etc. is stored. As described above, it is preferable to be able to grasp a subtle difference in the charging amount of the refrigerant by the supercooling degree of the refrigerant at the outlet of the condenser in addition to the liquid level of the liquid reservoir 28. Thereafter, in step S3, the control unit 103 starts normal air conditioning operation control. In the normal operation, the control unit 103 controls the liquid level detection temperature sensors 27a and 27b to be closed.

In step S4, the control unit 103 determines whether a predetermined time has elapsed since the first trial run or the previous leakage determination, and proceeds to the next step 5 if the predetermined time has elapsed. In step S5, the process waits until the refrigeration cycle is stabilized, and in step S6, the control unit 103 confirms whether all the indoor heat exchangers in the indoor unit are in the heating operation or the heating operation. Further, as in step S7, it is determined whether or not the outside air temperature is a value close to the temperature at the time of the initial liquid level determination (for example, a range of ± 5 ° C.), and is determined only when it is within a predetermined temperature range. However, if it is impossible to keep the temperature within the predetermined temperature range, step S7 may be skipped.
After these steps S4 to S7, when the operation state of the refrigeration air conditioner becomes substantially the same as the outside air temperature, the operation mode, and the operation state of the indoor unit stored in step S2, the operation determination unit 108 causes the refrigerant leakage in step S8. In step S9, the presence or absence of refrigerant leakage is determined based on the appropriate amount and the inappropriate amount of refrigerant. Specifically, the determination in step S8 is that the refrigerant amount determination throttling devices 25a and 25b are opened, and the detected temperatures of the liquid level detection temperature sensors 27a and 27b are higher than the temperature stored during the trial operation by a predetermined value or more. Is confirmed, the liquid level of the liquid reservoir 28 is lowered and it is determined that the refrigerant has leaked. In that case, it progresses to step S10, it displays on a remote control, a display, etc. from the alerting | reporting part 107 that there existed a refrigerant | coolant leak, and operation | movement of an apparatus is stopped by step S11.
When a negative determination is made in steps S4 to S7, the refrigerant amount determination expansion devices 25a and 25b are closed again, and the normal air conditioning operation is resumed. Further, when it is determined in step S9 that the refrigerant amount is within the appropriate range, the operation integration time of the compressor 1 is reset (step S9 ′), and then the routine proceeds to a normal air conditioning operation.

  By the way, the density of the liquid and gas of the refrigerant changes according to the pressure and temperature in the refrigerant circuit. For this reason, in consideration of changes in the density of the refrigerant in each element of the refrigerant circuit due to the pressure and temperature in the refrigerant circuit, correction is performed when the value measured at the time of determination differs from the initially stored pressure and temperature. Is preferred. As a correction method, for example, the relationship between the condenser outlet supercooling degree and the amount of refrigerant in the condenser is grasped in advance, and according to the measured difference in the condenser outlet supercooling degree, Correct the refrigerant amount difference. Thereby, even if the liquid level of the liquid reservoir 28 is the same, it may be determined that the leakage is caused by the difference in the refrigerant amount inside the condenser. The same problem can be dealt with by using the evaporator superheat degree and the compressor discharge superheat degree. In addition, the pipe length is input to the storage unit 104 during the trial operation, the refrigerant density is calculated from the temperature and pressure of the pipe, the refrigerant amount in the pipe is calculated from the stored pipe length and the calculated refrigerant density, A determination of refrigerant leakage may be made.

  Further, it is preferable that the initial value of the refrigerant amount is reset at a timing when the refrigerant is removed by repairing the refrigerant circuit or the like, and a trial operation is performed again at the next operation and stored as an initial value. The reset method may be that the operator manually operates the reset switch, or when the detected value of the pressure sensor falls below a predetermined value, it is determined that the refrigerant in the refrigerant circuit has been recovered, and is automatically It may be reset.

  As described above, in the third embodiment, the initial liquid state of the liquid reservoir 28 is detected and stored as the temperature of the bypass refrigerant in the upper part of the liquid reservoir 28, and in the subsequent refrigerant leakage detection, By detecting an increase or decrease in the amount of refrigerant in the circuit by detecting an increase in temperature and thereby detecting leakage of the refrigerant, refrigerant leakage can be easily detected.

  Further, by storing the operation state of the refrigeration cycle in the storage unit 104, it is possible to estimate the initial refrigerant amount (including the overfilled state) by the condenser outlet supercooling degree and the evaporator outlet superheat degree. Become. Thus, by comparing the initial refrigerant amount with the refrigerant amount at the time of leakage determination, even when a small amount of refrigerant leaks, it can be detected. Therefore, the detected coolant leakage is reported to the remote controller or the like, so that the coolant leakage location can be corrected at an early stage. Further, since the apparatus is stopped when the refrigerant leaks, the compressor can be prevented from being overheated by continuing the operation in a state where the refrigerant is insufficient, and the compressor can be prevented from being damaged.

  In addition, the initial operation mode and the outside air temperature are stored, and leak detection is performed at the same operation mode and the same outside temperature, thereby reducing the influence of density changes in the refrigerant piping due to the difference between the operation mode and the outside air temperature. Therefore, it is possible to accurately detect refrigerant leakage with a simple algorithm.

  Furthermore, in the refrigerant leakage determination, the operating state of the indoor unit is constantly monitored, and the refrigerant amount can be determined while the air conditioner user is performing the air conditioning operation as necessary. There is no need to contribute to energy saving. In addition, unnecessary air conditioning operation for refrigerant leakage determination does not give the user unpleasant feeling.

Embodiment 4 FIG.
Next, an embodiment of a refrigeration air-conditioning system using a centralized controller that centrally controls a plurality of refrigeration air-conditioners and a remote management device will be described.
FIG. 8 is a configuration diagram of an air conditioning system that integrally manages the refrigeration air conditioners of Embodiments 1 to 3 described above.
The refrigerating and air-conditioning apparatus having the indoor unit 110 and the outdoor unit 100 is connected to the centralized controller 120 via a communication line 121 laid in the building. The centralized controller 120 is typically a control device that is provided in the same building as the refrigeration air conditioner to be controlled and controls one or more refrigeration air conditioners. The centralized controller 120 performs a plurality of controls such as activation and stop of the indoor unit 110 and the outdoor unit 100, set temperature control, air volume and direction control, and monitoring the operating status of the refrigeration air conditioner and detecting abnormalities.
The indoor unit 100 and the outdoor unit 110 transmit the following operation status data regularly or irregularly.
(1) Detected temperature information of each temperature sensor 11, 13, 14, 15a, 15b, 16a, 16b, 17a, 17b, that is, refrigerant temperature, indoor / outdoor temperature, etc.
(2) detected pressure information of each pressure sensor 12, 19;
(3) Various control parameters of the control unit 103 (for example, compressor drive frequency, set temperature, air volume, operation mode, fan rotation speed, compressor operation time, compressor start / stop count set directly by the user in the indoor unit) etc).
The centralized controller 120 does not need to collect all of these information, and appropriately selects and sets necessary information based on the type and characteristics of the refrigeration air conditioner, control according to the user's request, and the like.

  The remote monitoring device 130 is connected to one or a plurality of centralized controllers 120 via a communication line 131, monitors the operating state of the refrigeration air conditioner in each building, and collects information necessary for maintenance when an abnormality occurs. To do. In addition, the remote monitoring device 130 has a function of performing energy saving control or the like according to the user's request to the centralized controller 120, and is provided in a remote monitoring center that controls facility equipment in each building from a remote location outside each building. ing. The communication line 131 is a wired / wireless telephone line, a communication line using the Internet protocol, or the like, and is called a public line.

  Next, the operation of this refrigeration air conditioning system will be described using the sequence diagram of FIG. Since the refrigeration air conditioner basically detects refrigerant leakage as described in FIGS. 2, 4, and 6, the following explanation focuses on the cooperative operation of the refrigeration air conditioner, centralized controller 120, and remote monitoring device 130. Explained.

First, when the refrigerant is filled in the refrigeration air conditioner, the control unit 103 of the refrigeration air conditioner starts and drives the outdoor unit 100 and all the indoor units 110 in the trial operation mode (step S21). Typically, a trial run is performed when a new refrigeration air conditioner is installed in a building. However, when the outdoor unit 100 or the indoor unit 110 is replaced, or when refrigerant is replaced or additionally charged, etc. This process is also executed.
Next, the control unit 103 determines driving stability (step S22). Note that the stability is determined by the same method as in step S2 of FIG. The control unit 103 continues to drive until the refrigeration cycle is stabilized, and determines the refrigerant amount after the stability is confirmed (step S25). The refrigerant amount is determined by the calculation unit 102 or the control unit 103 of the refrigeration air-conditioning apparatus using the same method as in the first to third embodiments. However, any method can be used as long as the refrigerant amount can be substantially specified. May be used.
Subsequently, the control unit 103 records the determined refrigerant amount together with the determination time in the storage unit 104 as history data (step S26). The history data may be a single initial data or a plurality of data recorded in time series in addition to the determination of the refrigerant amount. However, the initial data at the time of charging the refrigerant is important in determining the total amount of refrigerant leakage.
The initial determination and recording of the refrigerant amount described above are not limited to the trial operation, and may be performed during normal operation in a period in which the refrigerant amount does not change significantly due to slow leak after charging the refrigerant.

Thus, the initial operation after filling the refrigerant is completed, and the normal operation is started.
Thereafter, the refrigeration and air-conditioning apparatus repeats starting and stopping in accordance with the user's power on / off operation, the centralized controller 120, or the start / stop command of the remote monitoring device 130. During this time, the control unit 103 stores the data periodically or irregularly. The elapsed time from the time stored in the unit 104 is monitored (step S27). When it is determined that a predetermined time (for example, 1 month, 3 months, 6 months, 1 year, etc.) has elapsed, the refrigeration air conditioner performs refrigerant leakage determination. This predetermined time is set to a sufficiently long time after the refrigeration cycle is repeatedly started and stopped, so that a slow leak with a very small amount of refrigerant leakage per unit time can be detected. Specifically, the control unit 103 transmits an activation signal to the outdoor unit 100 and all the indoor units 110, and activates these devices (step S21a). As described above, all the indoor units 110 are operated in order to increase the accuracy of measuring the refrigerant amount. However, if it is desired to avoid driving the indoor unit 110 when the user does not expect it, the determination timing of the refrigerant amount is shifted. You can also. For example, the control unit 103 determines whether all the indoor units 110 are operating after a predetermined time has elapsed based on its own control data or an operation signal from each indoor unit 110, and the amount of refrigerant until the all indoor units 110 are driven. Postpone the decision. And after confirming that all the indoor units 110 have started, you may make it transfer to the next step.

Subsequently, the control unit 103 determines operation stability (step S22), and determines the refrigerant amount (step S25). The determined refrigerant amount is stored in the storage unit 104 (step S26). Note that this step may be omitted when only refrigerant amount data at the time of refrigerant charging is used for periodic refrigerant leakage determination and history data of refrigerant amount is unnecessary.
Next, the calculation determination unit 108 of the refrigerating and air-conditioning apparatus stores the refrigerant amount data (that is, past data related to the past refrigerant amount) stored in the storage unit 104 and the current refrigerant amount data (ie, the past refrigerant amount). The new refrigeration cycle is stopped and started once or a plurality of times after the previous time), and it is determined whether the difference between the two is within a predetermined range (step S29). . When this difference is not within the predetermined range, the operation determination unit 108 determines that there is a refrigerant leak. And the alerting | reporting part 107 receives this determination result, and transmits a determination result to the centralized controller 120 and the remote monitoring apparatus 130 (step S30). Even when there is no refrigerant leakage, it is preferable that the central controller 120 and the remote monitoring device 130 can recognize the determination result by transmitting the determination result. The data to be transmitted includes the determination time, determination result, refrigerant amount history data, current refrigerant amount data, and the like.

  Receiving the determination result via the communication line 121, the centralized controller 120, and the communication line 131, the remote monitoring device 130 automatically generates a leakage inspection document based on the determination result. For example, standard format document data is stored in the storage device of the remote monitoring device 130, and the control unit of the remote monitoring device 130 performs the received determination, determination result, refrigerant amount history data, current refrigerant A leakage inspection document is automatically generated by adding a quantity of data to the document data in a fixed format. The controller of the remote monitoring device 130 can send the leakage inspection document to the manager who manages the building by printing the leakage inspection document using a printer.

  The embodiment of the refrigerating and air-conditioning system having the refrigerant leak detection function has been described above. According to this embodiment, since the refrigerant leakage is detected by the difference after the start and stop are repeated, the slow leak of the refrigerant that could not be detected conventionally can be detected. Further, since the refrigerant leakage inspection is automatically performed at a predetermined timing, it is possible to reliably detect the slow leak without forgetting the inspection.

Embodiment 5 FIG.
In the fourth embodiment, the refrigerant leakage detection is performed by the refrigeration air conditioner itself. Next, an embodiment in which the central controller 120 performs refrigerant leakage detection will be described. In this embodiment, since the refrigerant leakage is detected by the centralized controller 120, there is an advantage that the refrigerant leakage can be detected even when the refrigeration air conditioner itself does not have a detection function capable of detecting the slow leak.
In this embodiment, as shown in FIG. 10, the central controller 120 is provided with a control unit 103 and a calculation determination unit 108. Here, the control unit that controls the operation of the refrigeration air conditioner is in the refrigeration air conditioner, but the control unit 103 that controls the refrigerant leakage determination and the calculation determination unit 108 are provided in the centralized controller 120. The control unit 103 controls the refrigerant leakage determination timing and the refrigerating and air-conditioning apparatus via the communication line 121, and the calculation determination unit 108 performs refrigerant amount determination and refrigerant leakage determination. In FIG. 10, the remote monitoring device 130 is also provided with the control unit 103 and the calculation determination unit 108, but these are used when the remote monitoring device 130 performs refrigerant leakage determination as in the embodiment described later. Used but not required.
FIG. 11 is a sequence diagram for explaining the operation of the refrigerating and air-conditioning system according to the fifth embodiment. 11, the same reference numerals as those in FIG. 9 indicate the same or corresponding processes, and the following description will focus on parts that are different from the processes in FIG. 9.

When the refrigeration air conditioner is filled with the refrigerant, the control unit 103 of the refrigeration air conditioner transmits a signal indicating that the refrigerant is filled to the centralized controller 120 (step S20). Note that the refrigerant charging notification in this step does not need to be automatically performed, and it can be determined based on a signal input by the maintenance operator by providing an input unit in the centralized controller 120.
Thereafter, the control unit 103 of the refrigeration air conditioner determines whether or not the refrigeration cycle is stabilized (step S22). Whether or not the refrigeration cycle is stable may be determined by the refrigeration air conditioner itself as described in the first or second embodiment. Alternatively, it may be received by a plurality of times (step S23) and determined by a similar algorithm (step S22).

  The centralized controller 120 receives the operation status data transmitted by the refrigeration air conditioner, and the calculation determination unit 108 of the centralized controller 120 determines the refrigerant amount based on the operation status data (step S24). When the refrigerant amount is specified by the same algorithm as in the first embodiment, the operating condition data includes the refrigerant subcooling degree SC at the condenser outlet, the difference between the outside air temperature and the condensation temperature dTc, the constant pressure liquid specific heat Cpr of the refrigerant, Receives the refrigerant temperature such as the enthalpy difference Δhcon between the condenser inlet and the condenser outlet, the outside air temperature, and the pressure data in the refrigeration cycle. When a refrigerating and air-conditioning apparatus similar to that of the third embodiment is connected, the temperature information of the liquid level detection temperature sensor is received to determine the refrigerant amount. When this embodiment is connected to an existing refrigeration air conditioner, the type of operation status data transmitted from the refrigeration air conditioner may differ, so the centralized controller 120 supports each of multiple types of operation status data. Then, it is preferable to prepare a refrigerant amount determination algorithm and select the refrigerant determination algorithm to be used by matching the received operation status data with data necessary for the refrigerant determination algorithm. The refrigerant amount determination algorithm can be selected according to the model number of the refrigeration air conditioner.

Next, the centralized controller 120 records the refrigerant amount and time in the memory (step S26), and transmits an activation command to the refrigeration air conditioner after a predetermined time has elapsed (step S31). This activation command is a command for activating the outdoor unit 100 and all the indoor units 110. Needless to say, transmission is not necessary when all the indoor units 110 are already in operation. The centralized controller 120 manages the activation, operation mode, set temperature, etc. of one or a plurality of refrigeration air conditioners, but according to the activation program stored in advance in the centralized controller 120 until the time when all the indoor units 110 are operated. It is also possible to send a start command for all the indoor units 110 after waiting.
After the central controller 120 or the refrigeration air conditioner determines that the operation of the refrigeration cycle is stable, the central controller 120 receives the operation status data from the refrigeration air conditioner and determines the refrigerant amount (step S24). The determined refrigerant quantity is recorded in the memory (step S26). Then, the centralized controller 120 determines refrigerant leakage based on the difference between the past refrigerant amount data and the current refrigerant amount data (step S29), and transmits it to the remote monitoring device 130 (step S30).

  As described above, according to the refrigerating and air-conditioning system of this embodiment, there is an advantage that refrigerant leakage can be detected even when the refrigerating and air-conditioning apparatus does not have a function of detecting a slow leak of the refrigerant. Moreover, since the centralized controller 120 that manages the operation schedule of the refrigeration air conditioner performs refrigerant leakage detection, it is possible to detect refrigerant leakage while keeping a predetermined operation schedule.

Embodiment 6 FIG.
Next, an embodiment in which the refrigerant amount is measured by the centralized controller 120 and refrigerant leakage is determined by the remote monitoring device 130 will be described. According to the refrigerating and air-conditioning system of this embodiment, there is an advantage that refrigerant leakage detection can be stably performed regardless of the setting of the local centralized controller 120 when refrigerant leakage detection is performed periodically. .
FIG. 12 is a sequence diagram for explaining the operation of the refrigerating and air-conditioning system according to the fifth embodiment. 12, the same reference numerals as those in FIG. 11 indicate the same or corresponding processes, and the following description will focus on the parts different from the processes in FIG. 11.

The feature of this embodiment is that the remote monitoring device 130 performs refrigerant leakage determination. The centralized controller 120 determines the refrigerant amount, and transmits data related to the refrigerant amount to the remote monitoring device 130 via the communication line 131 (steps S24 and S25).
When the remote monitoring device 130 receives data indicating that the refrigerant has been charged from the centralized controller 120 (transmission of this data is optional), and receives data on the amount of refrigerant and time data, these data are stored (step S26). Start counting elapsed time. Then, when the predetermined time has elapsed, the remote monitoring device 130 transmits a refrigerant amount transmission request for requesting transmission of the refrigerant amount to the centralized controller 120 (step S28). However, this request is not essential, and the remote monitoring device 130 may determine the leakage of the refrigerant based on the data related to the amount of refrigerant sent from the centralized controller 120 periodically.

The centralized controller 120 may immediately determine the refrigerant amount, or may collect the operation status data by controlling the refrigeration air conditioner according to a predetermined operation schedule (step S23). However, the central controller 120 controls the operation of the refrigeration air conditioner so that a predetermined maximum delay time does not elapse after receiving the refrigerant amount transmission request. That is, when it is predicted that the maximum delay time will be exceeded from the operation schedule or the elapsed time after receiving the request, the centralized controller 120 determines whether the all indoor unit 110 activation signal and the operation status data are A signal for requesting transmission is transmitted to the refrigerating and air-conditioning apparatus, and data relating to the refrigerant amount is transmitted to the remote monitoring apparatus 130 within the maximum delay time.
Upon receiving the operation status data from the refrigerating and air-conditioning apparatus, the centralized controller 120 performs refrigerant quantity determination (step S24) and transmits data (new data) relating to the refrigerant quantity to the remote monitoring apparatus 130 (step S25).
The remote monitoring device 130 compares the data related to the past refrigerant amount received by the comparison unit 105 of the calculation determination unit 108 with the data related to the new refrigerant amount, and the determination unit 106 determines refrigerant leakage (step S29). After this determination, the remote monitoring device 130 transmits the determination result to the centralized controller 12 (step S30).

  As described above, even if the remote monitoring device 130 performs the refrigerant leakage determination, the same effect as the above-described embodiment is obtained. In addition, since the refrigerant amount transmission request is transmitted from the remote monitoring device 130, the refrigerant leakage detection can be stably performed regardless of the setting of the local centralized controller 120 when the refrigerant leakage detection is periodically performed. . Also, the refrigerant leakage detection schedule can be changed simultaneously from the remote monitoring device 130, which is much quicker and more reliable than when the refrigeration and air-conditioning unit is visited and the schedule is set. Changes can be made.

Embodiment 7 FIG.
The seventh embodiment is an embodiment in which the remote monitoring device 130 performs refrigerant amount determination and refrigerant leakage determination. Since the remote monitoring device 130 determines the refrigerant amount, there is a feature that even the centralized controller 120 that does not have the refrigerant amount determination function can perform the refrigerant leakage determination.
FIG. 13 is a sequence diagram for explaining the operation of the refrigerating and air-conditioning system according to the fifth embodiment. In FIG. 13, the same reference numerals as those in FIG. 12 indicate the same or corresponding processes, and the following description will focus on the parts different from the processes in FIG.
In this embodiment, the control unit 103 that controls refrigerant leakage determination and the calculation determination unit 108 that performs determination are provided in the remote monitoring device 130.

  When the refrigerant is filled, the refrigeration air conditioner transmits the operation status data to the remote monitoring device 130 via the centralized controller 120 (step S23). The remote monitoring device 130 determines the refrigerant amount based on the operation status data (step S24), and records the refrigerant amount and time (step S26). At this time, similar to the centralized controller 120 of the fifth embodiment, the remote monitoring device 130 selects a refrigerant amount determination algorithm that matches the transmitted operation status data from a plurality of refrigerant amount determination algorithms, and determines the refrigerant amount. Make a decision.

  Next, the remote monitoring device 130 determines the elapsed time while the refrigeration and air-conditioning apparatus is repeatedly stopped / started (step S27), and sends an operation status transmission request for requesting transmission of the operation status after the predetermined time has elapsed to the centralized controller 120. To the refrigerating and air-conditioning apparatus (step S28a). This operation status transmission request is not necessary when the operation status is periodically transmitted from the refrigeration air conditioner. In this case, if the remote monitoring device 130 determines whether all the indoor units 110 are operating or whether the refrigeration cycle is stable based on the operation status data sent periodically, the accuracy of refrigerant quantity detection is improved. Improve (steps S21 and S22).

  Subsequently, the remote monitoring device 130 determines the refrigerant amount based on the received operation data (step S24). Based on the past data and new data relating to the refrigerant amount, refrigerant leakage determination is performed (step S29). And although a refrigerant | coolant leak test document is produced | generated (step S32), when the centralized controller 120 receives the display data from the remote monitoring apparatus 130, the data of this refrigerant | coolant leak test report may be transmitted to the centralized controller 120 as a determination result. It is possible (step S30). In addition, third parties such as encryption cannot be freely viewed without going through the centralized controller 120, and transmitted directly to the building manager's terminal via the public line (communication line 131). You can also.

  As described above, according to the refrigerating and air-conditioning system of this embodiment, there is an advantage that the refrigerant leakage can be detected even when the refrigerating and air-conditioning apparatus and the centralized controller 120 do not have a function of detecting the slow leak of the refrigerant. . Further, by selecting / changing the refrigerant determination algorithm of the remote monitoring device 130, it is possible to cope with refrigerant leakage detection of various refrigeration air conditioners.

  Note that the determination of refrigerant leakage may be made based on operating status data during one operation, rather than after starting or stopping the refrigeration cycle of the refrigeration air-conditioning apparatus one or more times. In particular, when the refrigerant leakage determination means is provided in the centralized controller 120 or the remote monitoring device 130, there is an advantage that refrigerant leakage detection can be performed even for a refrigeration air conditioner that does not have a refrigerant leakage detection function. is there.

Claims (12)

A refrigerating and air-conditioning system comprising a refrigerating cycle in which an outdoor unit having a compressor, an outdoor heat exchanger and an expansion device, and one or a plurality of indoor units having an indoor heat exchanger and an expansion device are connected by a communication pipe. In the system,
There are a plurality of the outdoor heat exchanger or the indoor heat exchanger acting as a condenser,
Based on past data relating to the past refrigerant amount of the refrigeration cycle and new data relating to the refrigerant amount after the refrigeration cycle has been stopped and started a plurality of times from the past time point, refrigerant leakage of the refrigeration cycle is reduced. A determination means for determining,
The determination means calculates a liquid phase area ratio that is a liquid phase volume ratio of the total volume of the outdoor heat exchanger or the indoor heat exchanger acting as a condenser based on a plurality of parameters, and calculates the calculated liquid Comparing the phase area ratio with past history data to determine refrigerant leakage ,
The liquid phase area ratio A _L % is
The refrigerant subcooling degree at the condenser outlet is SC, the difference between the outside air temperature and the condensation temperature is dTc, the constant pressure liquid specific heat of the refrigerant is Cpr, the enthalpy difference between the condenser inlet and the condenser outlet is Δhcon, and When the heat exchange capacity is Q _j (k), the following formula

Where k is the condenser number and n is the total number of condensers
The refrigeration air conditioning system characterized by being calculated by the following .   The determination means compares initial operation status data after the refrigerant is charged into the refrigeration cycle as the past data, and compares operation status data after the refrigeration cycle is stopped and started a plurality of times as the new data. The refrigerating and air-conditioning system according to claim 1.   The integration means for integrating the operating time of the compressor is provided, and the determination means determines the refrigerant leakage when the integration time of the integration means has passed a predetermined time. The refrigeration air conditioning system described.   The refrigerating and air-conditioning system according to claim 1, further comprising a time measuring unit, wherein the determination unit performs the refrigerant leakage determination when the time measuring unit measures a predetermined date and time.   The determination means determines the refrigerant leakage when the outside air temperature is within a predetermined range with respect to the outside air temperature at the time of collecting data to be compared in the determination of refrigerant leakage, and when a predetermined time has elapsed since the data collection. The refrigeration air conditioning system according to claim 1 or 2, wherein the refrigeration air conditioning system is performed.   The detection means for detecting a change in a physical quantity on a refrigeration cycle, wherein the determination means determines the refrigerant leakage when a change value detected by the detection means is within a predetermined range. The refrigerating and air-conditioning system according to any one of 1 to 5.   The said determination means performs determination of refrigerant | coolant leakage, when all the indoor heat exchangers which comprise the said indoor unit are carrying out air_conditionaing | cooling operation or heating operation. The refrigeration air conditioning system according to one item. In the case where an accumulator is arranged on the suction side of the compressor, the determination means determines that the liquid refrigerant does not stay in the accumulator and determines the refrigerant leakage. The refrigerating and air-conditioning system according to any one of claims 1 to 7 . 9. The refrigerating and air-conditioning system according to claim 1, wherein during the refrigerant leakage determination, a display to that effect is displayed on a remote controller and / or a display device of the indoor unit . An informing means for informing the outside of the determination result of the refrigerant leakage is provided, and when it is determined that the refrigerant is leaking, a message to that effect is displayed on the remote controller and / or display device of the indoor unit. The refrigerating and air-conditioning system according to any one of 1 to 9 . The determination means is provided in a centralized controller that controls a plurality of refrigeration air conditioners, or a remote monitoring device that is connected to the plurality of centralized controllers via a communication line and remotely monitors the refrigeration air conditioners. The refrigeration air conditioning system according to any one of claims 1 to 10 . A refrigerating and air-conditioning system comprising a refrigerating cycle in which an outdoor unit having a compressor, an outdoor heat exchanger and an expansion device, and one or a plurality of indoor units having an indoor heat exchanger and an expansion device are connected by a communication pipe. In the refrigerant leakage detection method for a refrigerating and air-conditioning apparatus having a plurality of the outdoor heat exchanger or the indoor heat exchanger acting as a condenser,
Determining an elapsed time after filling the refrigerant;
Determining whether the total number of indoor heat exchangers constituting the indoor unit is cooling or heating; and
  When it is determined that all the indoor heat exchangers constituting the indoor unit are in cooling operation or heating operation, all of the indoor heat exchanger or the outdoor heat exchanger acting as a condenser Calculating a liquid phase area ratio which is a liquid phase volume ratio of the volume based on a plurality of parameters, comparing the calculated liquid phase area ratio with past history data, and determining refrigerant leakage;
With
Liquid phase area ratio A _L %
The refrigerant subcooling degree at the condenser outlet is SC, the difference between the outside air temperature and the condensation temperature is dTc, the constant pressure liquid specific heat of the refrigerant is Cpr, the enthalpy difference between the condenser inlet and the condenser outlet is Δhcon, and Q for heat exchange capacity _j where (k)

Where k is the condenser number and n is the total number of condensers
The refrigerant leakage detection method characterized by calculating by this.

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