JP7412221B2 - Refrigerant leakage state determination method, refrigerant leakage state determination device, and refrigerant leakage state monitoring system - Google Patents

Description

The present invention provides a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant condensed in the condenser, and a refrigerant expanded in the expansion valve. A refrigerant leak state determination method in a heat pump device comprising an evaporator that evaporates, and a refrigerant circulation path that circulates refrigerant in the order described in the compressor, the condenser, the expansion valve, and the evaporator, using the method The present invention relates to a refrigerant leakage state determination device and a refrigerant leakage state monitoring system.

Conventionally, there has been a compressor that compresses refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant condensed in the condenser, and an evaporator that evaporates the refrigerant expanded by the expansion valve. An air conditioner is known that determines the presence or absence of refrigerant leakage in a heat pump device that includes a compressor, a condenser, an expansion valve, and an evaporator, and a refrigerant circulation path that circulates the refrigerant in the order described (Patent Document 1).
In an operation mode in which the air conditioner is operated under predetermined refrigerant leakage determination conditions, the operating state changes according to fluctuations in the degree of refrigerant subcooling at the outlet of the heat source side heat exchanger (condenser in cooling operation). The presence or absence of refrigerant leakage is determined based on the amount.

Patent No. 4270197

Although the technology disclosed in Patent Document 1 can determine the presence or absence of refrigerant leakage, it is necessary to operate under predetermined refrigerant leakage determination conditions. However, there was room for improvement as this would place restrictions on users' use.
Furthermore, the technique disclosed in Patent Document 1 has a problem in that it is not possible to appropriately know the degree of leakage, such as how much refrigerant is leaking.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to prevent leakage while continuing normal operation without placing restrictions on the operating state in a heat pump device having a refrigerant circulation path that circulates refrigerant. It is an object of the present invention to provide a refrigerant leakage state determination method capable of determining the leakage state including the degree of leakage, a refrigerant leakage state determination apparatus capable of executing the determination method, and a refrigerant leakage state monitoring system.

The refrigerant leak status determination method to achieve the above purpose is as follows:
A compressor that compresses refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant condensed in the condenser, and an evaporator that evaporates the refrigerant expanded in the expansion valve. A method for determining a refrigerant leakage state in a heat pump device comprising: a refrigerant circulation path that circulates refrigerant in the order described in the compressor, the condenser, the expansion valve, and the evaporator;
a degree of superheat calculation step of calculating the degree of superheat by subtracting the evaporation temperature from the refrigerant suction temperature at the inlet of the compressor;
A degree of supercooling calculation step of calculating the degree of supercooling by subtracting the refrigerant temperature at the condenser outlet from the condensation temperature;
In the case where there is at least one evaporator, a value obtained by converting the expansion valve opening degree based on the capacity ratio of the evaporator with respect to the evaporator in operation and the expansion valve corresponding to the evaporator. an operating evaporator average opening degree derivation step of deriving an operating evaporator average opening degree as an average value;
A superheat degree maintenance step of maintaining the superheat degree at a reference superheat degree during normal operation;
The operating evaporator in which the supercooling degree calculated in the supercooling degree calculation step is zero in the state in which the superheat degree maintaining step is executed, and the operating evaporator average opening degree deriving step The average opening exceeds the standard average opening which exceeds the average opening which is the average opening of the operating evaporator under rated conditions during normal operation by a predetermined value, and is the maximum value of the average opening of the operating evaporator. Refrigerant leakage degree determination that determines that the degree of refrigerant leakage is in a moderate leakage state when the degree of superheating calculated in the superheating degree calculation step is maintained at the reference degree of superheating when the opening degree is less than the maximum average opening degree. The point is that it includes the process.

The refrigerant leakage state determination device for achieving the above purpose is as follows:
A compressor that compresses refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant condensed in the condenser, and an evaporator that evaporates the refrigerant expanded in the expansion valve. A refrigerant leakage state determination device in a heat pump device, comprising a refrigerant circulation path that circulates refrigerant in the order described in the compressor, the condenser, the expansion valve, and the evaporator, the characteristics of which are as follows:
a superheat degree calculation unit that calculates the degree of superheat by subtracting the evaporation temperature from the refrigerant suction temperature at the compressor inlet;
a supercooling degree calculation unit that calculates a supercooling degree by subtracting the refrigerant temperature at the condenser outlet from the condensing temperature;
In the case where there is at least one evaporator, a value obtained by converting the expansion valve opening degree based on the capacity ratio of the evaporator with respect to the evaporator in operation and the expansion valve corresponding to the evaporator. an operating evaporator average opening degree derivation unit that derives an operating evaporator average opening degree as an average value;
a superheat degree maintenance section that maintains the superheat degree at a reference superheat degree during normal operation;
the operating evaporator in which the supercooling degree calculated by the supercooling degree calculation unit is zero in a state in which the superheat degree maintaining unit is executed, and the operating evaporator average opening degree deriving unit derives the operating evaporator; The average opening exceeds the standard average opening which exceeds the average opening which is the average opening of the operating evaporator under rated conditions during normal operation by a predetermined value, and is the maximum value of the average opening of the operating evaporator. Refrigerant leakage degree determination that determines that the degree of refrigerant leakage is in a moderate leakage state when the degree of superheating calculated by the superheating degree calculation unit is maintained at the reference degree of superheating when the opening degree is less than the maximum average opening degree. The point is that it has a part.

The inventors have newly discovered that the combination of parameters related to a heat pump device changes uniquely depending on the state of refrigerant leakage.
The above characteristic structure is based on the knowledge, and as shown in FIGS. 2, 3, and 4, when the degree of supercooling calculated in the degree of supercooling calculation step is zero in the state in which the degree of superheating is maintained, the degree of supercooling is zero. , and the operating evaporator average opening calculated in the operating evaporator average opening degree calculation process exceeds the reference average opening degree and is less than the maximum average opening degree, and the superheating calculated in the superheating degree calculation process We have newly discovered that if the temperature is maintained at the standard superheat level, the degree of refrigerant leakage can be said to be moderate.
As a result, for example, as a manager of a heat pump device, when actually inspecting the device, it is important to note that the leakage level is lower than the moderate leakage condition, but it is more important to check whether the leakage condition is smaller than the moderate leakage condition, and is more important than the small leakage condition, which includes no leakage. A moderate leakage state in which it is easy to detect whether a leakage has occurred can be actively detected as a leakage state.
In addition, since the determination of the leakage state can be used regardless of whether the heat pump device is operating at a rated load or a medium load, there is no operational restriction on the user side of the heat pump device. Since it can be executed without any additional time, the degree of freedom in operation can be improved compared to conventional leakage determination.
As described above, in a heat pump device having a refrigerant circulation path that circulates refrigerant, there is provided a refrigerant leakage state determination method that can determine the leakage state including the degree of leakage while continuing normal operation without placing restrictions on the operating state, and the refrigerant leakage state determination method. A leak state determination device can be realized.

Further, the expansion valve opening degree can be expressed as the "expansion valve area" in addition to the "step number" that indicates the opening degree of the expansion valve in the actual machine. Below, an example of a numerical value of the operating evaporator average opening degree will be shown when "expansion valve area" is used as a parameter corresponding to the expansion valve opening degree.
For example, Table 1 shows an example of the operating state under rated conditions when four evaporators are connected. #1 and #2 are examples of evaporators with relatively large capacities, and #3 and #4 are examples of evaporators with relatively small capacities.
The simple average of the underlined portion = 10 mm ² , and the value under this rated condition is taken as 100%.

[Table 1]

Next, examples of operating conditions under other conditions are shown in [Table 2]. The simple average of the underlined portion is 10 mm ² and the area ratio is 100%.

[Table 2]

Note that the operating evaporator average opening here is a value with the value at rated operation during normal operation as 100%, and is not only a simple average but also the indoor heat exchanger capacity (condenser opening during heating operation). Alternatively, it may be an average weighted by the capacity (capacity) of the evaporator during cooling operation.

Further characteristics of the refrigerant leakage state determination method are as follows:
The refrigerant leakage degree determination step includes:
When the degree of superheating is maintained, the degree of supercooling calculated in the degree of supercooling calculation step is greater than zero, and the degree of supercooling calculated in the degree of supercooling calculation step is greater than zero, and When the average opening of the operating evaporator is less than the maximum average opening and the degree of superheat calculated in the degree of superheat calculation step is maintained at the standard degree of superheat, the degree of refrigerant leakage is medium leakage. The point is that it is determined that the state is a state where the degree of leakage is less than the state and there is a slight leakage state, which includes no leakage.

According to the above characteristic structure, it is known that the refrigerant leakage state is a small leakage state with a relatively small amount of leakage, so the urgency to respond is lower than, for example, a technology that only shows the presence or absence of a refrigerant leakage. It is possible to determine whether there is a leak, etc. As a result, it is possible to increase the options for the administrator's response after knowing the determination result, reduce the burden on the administrator, and make it possible to respond appropriately depending on the leakage state at the site.

Further characteristics of the refrigerant leakage state determination method are as follows:
The refrigerant leakage degree determination step includes:
The operating evaporator in which the supercooling degree calculated in the supercooling degree calculation step is zero in the state in which the superheat degree maintaining step is executed, and the operating evaporator average opening degree deriving step When the average opening is the maximum average opening and the degree of superheat calculated in the degree of superheat calculation step is greater than the reference degree of superheat, the degree of leakage of the refrigerant is greater than the degree of leakage in the medium leakage state. The point is that it is determined that there is a leakage state to some extent.

According to the above characteristic structure, it is known that the refrigerant leakage state is a multi-level leakage state with a relatively large amount of leakage, so the urgency of the response is higher than, for example, technology that only shows the presence or absence of refrigerant leakage. It is possible to determine whether there is a leak, etc., and this can lead to prompt response after the determination.

Further characteristics of the refrigerant leakage state determination method are as follows:
The refrigerant leakage degree determination step includes:
The combination of the values of the degree of supercooling, the average opening of the operating evaporator, and the degree of superheat is other than the combination of values specified in the medium leakage state, the small leakage state, and the large leakage state. In this case, the operation state of the heat pump device is considered to be different from the normal operation and is excluded from the determination of the degree of leakage.

For example, if the heat pump device is not in normal operating condition, such as immediately after starting operation, the degree of superheating is higher than the standard degree of superheating even though the average opening degree of the operating evaporator is about the standard average degree of opening. It may become.
According to the characteristic configuration described above, by excluding such cases from the determination of the leakage state, it is possible to improve the accuracy of determination of the leakage state.

Further characteristics of the refrigerant leakage state determination method are as follows:
The refrigerant leakage degree determination step includes:
The point is that the operating evaporator average opening degree derived in the operating evaporator average opening degree deriving step is corrected to a higher side as the evaporation pressure, which is the inlet pressure of the compressor, becomes higher.

As shown in Figure 7, the inventors found that when there is a leak (leakage rate is 40% in Figure 7), the higher the evaporation pressure, which is the inlet pressure of the compressor, the higher the average operating evaporator opening. We found that there is a trend.
According to the above characteristic configuration, the average operating evaporator opening derived in the average operating evaporator opening derivation process is corrected to the higher side as the evaporation pressure, which is the inlet pressure of the compressor, increases, so that the evaporation pressure is higher. Even in cases where the refrigerant leakage degree is determined effectively.
Incidentally, as can be seen from FIG. 7, the inventors have confirmed that such a tendency is substantially the same whether the load is the rated load or the intermediate load.

Further characteristics of the refrigerant leakage state determination method are as follows:
The refrigerant leakage degree determination step includes:
From the operating evaporator average opening degree and evaporation pressure derived in the operating evaporator average opening degree derivation step, a leakage rate is derived by dividing the refrigerant leakage amount by the regular filling amount without refrigerant leakage. At the point.

According to the above characteristic configuration, the amount of refrigerant leakage is divided by the normal filling amount without refrigerant leakage from the average operating evaporator opening and evaporation pressure derived in the average operating evaporator opening derivation process. Since the leakage rate can also be derived, the leakage state can be determined quantitatively using numerical values, and more appropriate post-processing can be performed based on the value.

Further characteristics of the refrigerant leakage state determination method are as follows:
The refrigerant leakage degree determination step includes:
The point is that the operating evaporator average opening degree derived in the operating evaporator average opening degree deriving step is corrected to a higher side as the degree of superheat increases.

As shown in FIG. 6, the inventors have found that when there is a leak (the leak rate is 40% in FIG. 6), the higher the degree of superheating, the higher the average opening of the operating evaporator tends to be.
According to the above feature configuration, the average operating evaporator opening derived in the average operating evaporator opening process is corrected to the higher side as the degree of superheating increases, so regardless of the value of the degree of superheating (standard degree of superheating). , the degree of refrigerant leakage can be determined with higher accuracy.
Incidentally, as is clear from FIG. 6, the inventors have confirmed that such a tendency is substantially the same whether the load is rated or an intermediate load.

Furthermore, as a refrigerant leak status determination system,
In addition to having the above-mentioned refrigerant leakage state determination device,
comprising a monitoring device electrically connected to the heat pump device through a network line,
Preferably, the monitoring device is configured to monitor the degree of leakage of the refrigerant.

According to the characteristic configuration described above, since the leakage determination can be performed by remote monitoring, the workload related to the leakage determination can be sufficiently reduced compared to the case where the administrator goes to each site and executes the leakage determination.

1 is a schematic configuration diagram of a refrigerant leakage state determination device and a refrigerant leakage state monitoring system according to a first embodiment; FIG. It is a graph diagram showing the result of deriving the relationship between the leakage rate and the degree of supercooling by calculation. FIG. 3 is a graph diagram showing the result of calculation of the relationship between the leakage rate and the average operating evaporator opening degree. It is a graph diagram showing the result of deriving the relationship between the leakage rate and the degree of superheat through calculation. FIG. 2 is a graph diagram showing the result of calculation of the relationship between the leakage rate and the degree of supercooling when parameters such as condensation pressure are changed. FIG. 3 is a graph diagram showing the influence of the degree of superheating on the average opening degree of the operating evaporator. FIG. 2 is a graph diagram showing the influence of compressor inlet pressure (evaporation pressure) on the average operating evaporator opening degree. It is a graph diagram for deriving the leakage rate in a small/medium leakage state from the evaporation pressure and the average opening degree of the operating evaporator. FIG. 2 is a schematic configuration diagram of a refrigerant leakage state determination device and a refrigerant leakage state monitoring system according to another embodiment. FIG. 2 is a graph diagram showing the result of calculation of the relationship between the degree of subcooling at the outlet of the supercooler and the amount of refrigerant charged (leakage amount). FIG. 2 is a graph diagram showing the result of calculation of the relationship between the degree of subcooling at the condenser outlet and the amount of refrigerant charged (leakage amount). FIG. 2 is a graph diagram showing the result of calculation of the relationship between the average opening degree of the operating evaporator and the refrigerant filling amount (leakage amount).

A refrigerant leakage state determination method according to an embodiment of the present invention, a refrigerant leakage state determination device 100 capable of executing the determination method, and a refrigerant leakage state monitoring system 200 are provided in a heat pump device having a refrigerant circulation path that circulates refrigerant. This invention relates to a device that can determine the leakage state, including the degree of leakage, while continuing normal operation without placing any restrictions on the leakage.
The embodiment will be described below based on FIGS. 1 to 8.

As shown in FIG. 1, the heat pump device H according to the refrigerant leak state determination device 100 according to the embodiment includes a compressor 11 that is rotationally driven by an engine 14 and compresses refrigerant, and a compressor 11 that is rotationally driven by an engine 14 and compresses the refrigerant. an expansion valve V that expands the refrigerant condensed in the condenser, an evaporator that evaporates the refrigerant expanded in the expansion valve V, a compressor 11, a condenser, an expansion valve V, and an evaporator. and a refrigerant circulation path C1 that circulates the refrigerant in the order described. That is, in this embodiment, the refrigerant circulation path C1 is provided without passing through a receiver that stores refrigerant.
The refrigerant circulation path C1 includes a four-way valve 20 that switches the refrigerant circulation state between cooling operation (operation in which the evaporator exerts its cooling capacity) and heating operation (operation in which the condenser exerts its heating capacity). is provided.
Further, an accumulator 15 for storing refrigerant is provided at the inlet of the compressor 11 to prevent refrigerant in a liquid phase from being introduced into the compressor 11.
Furthermore, an oil separator 16 is provided at the outlet of the compressor 11 to separate oil mixed into the refrigerant pipe from the compressor 11 from the refrigerant, and an oil flow connecting the oil separator 16 and the inlet of the compressor 11 is provided. An oil valve V3 is provided to open and close the passage Lo and the oil flow passage Lo, and the oil stored in the oil separator 16 is periodically transferred to the compressor by shifting the oil valve V3 from the closed state to the open state. You will be guided to the entrance of 11.

During cooling operation, as shown in FIG. 1, the refrigerant flowing through the refrigerant circulation path C1 is transferred to the outdoor air where the refrigerant exchanges heat with outdoor air blown by the compressor 11, oil separator 16, and fan (not shown). The heat exchanger 12 (corresponding to a condenser), the expansion valve V, and the indoor heat exchanger 13 (corresponding to an evaporator) that exchanges heat between the indoor air blown by a fan (not shown) and the refrigerant in the order described. The four-way valve 20 is switched to circulate.
On the other hand, during heating operation, although not shown, the refrigerant flowing through the refrigerant circulation path C1 exchanges heat with indoor air blown by the compressor 11, oil separator 16, and fan (not shown). An indoor heat exchanger 13 (equivalent to a condenser), an expansion valve V, and an outdoor heat exchanger 12 (equivalent to an evaporator) that exchanges heat between outdoor air blown by a fan (not shown) and a refrigerant. The four-way valve 20 is switched to circulate in sequence. Note that a heat exchanger that evaporates part of the refrigerant using exhaust heat from the engine 14 is often installed, but is not shown.

Furthermore, the refrigerant leak state determination device 100 according to the embodiment has the following configuration in order to measure various parameters of the heat pump device H.
The refrigerant leak state determination device 100 is a control device S realized by hardware and software working together, and performs superheat degree calculation that calculates the degree of superheat by subtracting the evaporation temperature from the refrigerant suction temperature at the inlet of the compressor 11. a subcooling degree calculating section S2 that calculates the degree of subcooling by subtracting the refrigerant temperature at the condenser outlet from the condensing temperature; and an operating evaporator in the case of having at least one evaporator; Regarding the expansion valve V corresponding to the indoor heat exchanger 13, the operating evaporator average is the average value of the expansion valve opening degree converted based on the capacity ratio of the evaporator (the divided value in this embodiment) It has an operating evaporator average opening degree deriving part S3 that derives the opening degree.
In this specification, the evaporator is described as the indoor heat exchanger 13 in order to explain the case of cooling operation as an example. can be applied, and in the case of heating operation, the evaporator becomes the outdoor heat exchanger 12.
Furthermore, the control device S functions as a superheat degree maintenance unit (not shown) that maintains the superheat degree at a predetermined reference superheat degree (5K in calculation results described later) when the heat pump device H is operated in a normal operating state. do.

Now, the refrigerant leakage state determination device 100 according to the embodiment is configured as follows in order to determine the leakage state including the degree of leakage while continuing normal operation without imposing restrictions on the operating state. .

The refrigerant leakage state determining device 100, as a control device S, determines that the degree of subcooling calculated by the degree of supercooling calculating section S2 is 0, and the operating evaporator average opening derived by the operating evaporator average opening deriving unit S3 is the average operating evaporator opening under the rated conditions during normal operation (in Figure 3). 100%) by a predetermined value (approximately 25% in the example of Fig. 3) exceeding the standard average opening (125%, L1 in Fig. 3) and less than the maximum average opening which is the maximum value of the operating evaporator average opening. A refrigerant that executes a refrigerant leakage degree determination step that determines that the degree of refrigerant leakage is in a moderate leakage state when the degree of superheating calculated by the degree of superheating calculation unit S1 is maintained at the reference degree of superheating. It has a leakage degree determination section S5.

The refrigerant leakage degree determination unit S5 is configured to be able to perform determination of a small leakage state and determination of a large leakage state in addition to the above-mentioned determination of a medium leakage state as a method of determining a refrigerant leakage state. .
To add an explanation, the refrigerant leakage degree determination unit S5 determines that the degree of supercooling calculated in the degree of supercooling calculation step is a value greater than zero while the degree of superheating maintaining step is being executed, and the evaporator is in operation. If the operating evaporator average opening calculated in the average opening derivation step is less than the maximum average opening, and the superheat degree calculated in the superheat degree calculation step is maintained at the reference superheat degree, the refrigerant It is determined that the degree of leakage is less than the moderate leakage state and is in the slight leakage state, which includes no leakage.
In addition, the refrigerant leakage degree determination unit S5 determines that the degree of supercooling calculated in the degree of supercooling calculation step is zero in the state in which the degree of superheating maintenance step is executed, and the degree of supercooling calculated in the degree of supercooling calculation step is zero, and the degree of supercooling is determined to be zero in the step of deriving the average opening of the operating evaporator. If the derived operating evaporator average opening is the maximum average opening and the degree of superheat calculated in the superheat degree calculation step is greater than the standard degree of superheat, the degree of refrigerant leakage is greater than the medium leak state. It is determined that there is some degree of leakage.

Furthermore, the refrigerant leakage degree determination process will be described in detail based on the simulation results shown in FIGS. 2, 3, and 4. In the graph, □ indicates a reference value in rated cooling operation.
Regarding heat pump device H, the inventors performed a simulation simulating direct expansion GHP of 20 HP in the case of simple flow. This simulation targets the cooling mode in the compression refrigeration cycle.
As for the components constituting the heat pump device H, the compressor 11 is fixed at a volumetric efficiency of 90%, the oil separator 16 is set in a space with a volume of about 4 L, and the condenser (outdoor heat exchanger 12) is: The number of stages is 54, the number of rows is 3, and the number is 2. A simple path allocation is set using a fin tube type with an inner diameter of 6.8 mm and a length of 1600 mm, and the liquid pipe as the refrigerant circulation path C1 has an inner diameter of 13.9 mm. The length is set to 50 m, the expansion valve V is one that can change the area of the orifice on the pipe, and the evaporator (indoor heat exchanger 13) has 18 stages, 3 rows, and 4 pieces, and the inner diameter It is a fin tube type with a diameter of 4.6 mm and a length of 2200 mm, and is set using a simple path division.The gas pipe as the refrigerant circulation path C1 is set with an inner diameter of 26.6 mm and a length of 50 m, and the accumulator 15 is approximately 8 L. is set in a space with a volume of .
In the above description, the number of condensers (outdoor heat exchanger 12) is 2, but this indicates that one heat exchanger is placed on the front and back of outdoor heat exchanger 12. .
On the other hand, in the above description, the number of evaporators (indoor heat exchangers 13) is four, which corresponds to the number of connected indoor heat exchangers 13. Under rated conditions, refrigerant flows to all indoor heat exchangers 13, but under partial load, etc., refrigerant flows only to some indoor heat exchangers 13. In this specification, it is expressed as a ratio of the number of evaporators in operation, and the rated condition is set to 100%, and the intermediate load described below is set to 50%.
Next, the calculation conditions are: condensation pressure is 2.9 MPaA, evaporator operation ratio is 100%, outside temperature is 35°C, degree of superheat is 5K, evaporation pressure is 0.75 MPaA, and degree of supercooling at standard filling amount. is 5K (17.5 kg), the upper limit of the operating evaporator average opening is 100% when the degree of supercooling (5K) is 300%, the adiabatic efficiency of the compressor 11 is 80%, the refrigerant is R410A, and the refrigerant is charged. The amount was set to 110% to 30% (refrigerant leak rate -10% to 70%).
In this specification, unless otherwise specified, the average operating evaporator opening degree is shown as 100% when rated operation is performed during normal operation.

Figure 2 is a graph showing the relationship between the refrigerant leak rate and the degree of supercooling, Figure 3 is the relationship between the refrigerant leak rate and the average operating evaporator opening, and Figure 4 is a graph showing the relationship between the refrigerant leak rate and the degree of superheating. It is.
From the simulation results, in a small leakage state (in FIGS. 2, 3, and 4, the leakage rate is 0% or more and less than the first threshold R1 (a value of about 15%)), when the superheat degree maintenance step is being executed, The degree of supercooling is greater than zero as shown in FIG. 2, and the average operating evaporator opening is less than the standard average opening (L1 in FIG. 3) as shown in FIG. It can be seen that the temperature is maintained at the reference superheat degree (5K in FIG. 4) as shown in FIG.
In a medium leakage state (in Figures 2, 3, and 4, the leakage rate is greater than or equal to the first threshold R1% and less than the second threshold R2 (a value of approximately 50%)), supercooling is 2, and the operating evaporator average opening exceeds the reference average opening (L1 in FIG. 3) and is less than the maximum average opening, as shown in FIG. , it can be seen that the superheat degree is maintained at the reference superheat degree (5K in FIG. 4) as shown in FIG.
In a state where there is a large degree of leakage (in Figures 2, 3, and 4, the leakage rate is equal to or higher than the second threshold R2%), the degree of supercooling is zero as shown in Figure 2 while the superheat degree maintenance step is being executed. Yes, and the operating evaporator average opening is the maximum average opening (300%) exceeding the standard average opening (L1 in Figure 3) as shown in Figure 3, and the degree of superheat is as shown in Figure 4. It can be seen that the value is larger than the standard superheat degree (5K in FIG. 4).
That is, in the refrigerant leak state determination method according to the present invention, the refrigerant leak state is determined based on the results of the above-mentioned simulation.

Note that the refrigerant leakage state determining device 100 according to the embodiment can determine the refrigerant leakage state as long as there is no restriction on the operating state of the heat pump device H and the heat pump device H is in a normal operating state.
However, for example, in the starting state (state until steady operation is reached) of the heat pump device H, the combination of the various parameters described above exhibits exceptional values. For example, in the starting state, the degree of superheat may exhibit a high value exceeding the reference degree of superheat even though the average opening degree of the operating evaporator is not at its maximum.
Therefore, in the refrigerant leakage degree determination step, the refrigerant leakage degree determination unit S5 determines whether the combination of the subcooling degree, the operating evaporator average opening degree, and the superheating degree is a medium leakage state, a small leakage state, and a large leakage state. If the combination of values is other than that specified in , it is assumed that the operating state of the heat pump device is different from normal operation and is excluded from the determination of the degree of leakage.

Next, the results of simulations conducted regarding the effects of changes in various environmental indicators and parameters on the degree of supercooling and the average opening of the operating evaporator will be explained based on FIGS. 5, 6, and 7.
First, Figure 5, which shows the relationship between the degree of supercooling and the leakage rate, shows the relationship between the condensing pressure: 2.6 to 3.2 MPaA, the ratio of the number of evaporators in operation: 25% to 100%, and the outside temperature: 25 to 35°C. This is the result when As is clear from FIG. 5, the degree of supercooling changed significantly in the hatched areas. That is, in the case of a small leak (positive degree of supercooling), it was found that the degree of supercooling itself changes greatly depending on the condensing pressure, the ratio of the number of units in operation, and the outside air temperature. However, the tendency that the degree of supercooling takes a value larger than zero below the first threshold R1 and becomes zero above the first threshold R1 is generally maintained. As a result, in the relationship between the degree of supercooling and the leakage rate according to the present invention, correction based on the condensing pressure, the ratio of the number of operating evaporators, and the outside air temperature is not necessary.

Next, FIG. 6 shows the relationship between the average operating evaporator opening degree and the degree of superheat. When the leakage rate is 40%, the rated load (outside air temperature 35°C, evaporator operating ratio 100%, condensing pressure 2.9 MPaA) and intermediate load (outside air temperature 30°C, evaporator operating ratio 50%, condensing pressure 2. 6 MPaA), it can be seen that as the degree of superheating increases, the average operating evaporator opening degree tends to decrease.
Therefore, in the refrigerant leakage degree determination step, the refrigerant leakage degree determination unit S5 corrects the operating evaporator average opening degree to a higher side as the degree of superheating increases.
In addition, since the characteristics are generally the same at rated load and intermediate load, it can be seen that the influence of condensing pressure, ratio of number of operating units, and outside temperature is not large.

Next, FIG. 7 shows the relationship between the average operating evaporator opening degree and the inlet pressure (evaporation pressure) of the compressor 11. When the leakage rate is 40%, the rated load (outside air temperature 35°C, evaporator operating ratio 100%, condensing pressure 2.9 MPaA) and intermediate load (outside air temperature 30°C, evaporator operating ratio 50%, condensing pressure 2. 6 MPaA), it can be seen that as the evaporation pressure increases, the average operating evaporator opening degree tends to decrease.
Therefore, in the refrigerant leakage degree determination step, the refrigerant leakage degree determination unit S5 corrects the operating evaporator average opening degree to a higher side as the evaporation pressure, which is the inlet pressure of the compressor 11, increases.
In addition, since the characteristics are generally the same at rated load and intermediate load, it can be seen that the influence of condensing pressure, ratio of number of operating units, and outside temperature is not large.

Furthermore, the inventors have determined that the average operating evaporator opening and evaporation pressure ( It is newly proposed that the leakage rate (or the filling rate that is obtained by subtracting the leakage rate from 100%) can be derived from the refrigerant leakage divided by the normal filling amount without any refrigerant leakage. I found it.
Specifically, as shown in Figure 8, in a graph in which the vertical axis shows the filling rate (100% - leakage rate) and the horizontal axis shows the average opening of the operating evaporator, the operating evaporator A graph diagram having a characteristic that the filling rate decreases as the average opening degree of the evaporator increases, in other words, a graph diagram having a characteristic that the filling rate is approximated to a power of the average opening degree of the operating evaporator was obtained.
Incidentally, the data in the graph shown in FIG. 8 is a value calculated from the results of the above-mentioned rated load condition and intermediate load condition, which had almost similar characteristics. Further, the graph shown in FIG. 8 can be calculated using the following [Formula 1] under the above-mentioned configuration and conditions.

[Formula 1]

Here, R: leakage rate, Pe: compressor inlet pressure (MPaA), Ev: average operating evaporator opening (%), a = -0.98, b = 1.75, c = -0.06, d=0.06, e=-0.72
Note that this value is a value when the above-described specific configuration of the heat pump device H is adopted, and will change if the system configuration is changed.

That is, since the refrigerant leakage degree determination unit S5 can determine the refrigerant leakage rate (or filling rate) in the refrigerant leakage degree determination step, the administrator can more accurately determine the leakage situation based on the value. You can work on recovery work while keeping track of the situation. In addition, in FIG. 8, the leakage rate (filling This example shows the case of deriving the ratio).

A refrigerant leakage state determination device 100 according to the present invention can be configured as a refrigerant leakage state monitoring system including a monitoring device K via a network line N, as shown in FIG. With this configuration, the determination result determined by the refrigerant leakage degree determination unit S5 of the control device S can be constantly monitored by the monitoring device K, and the refrigerant It is possible to grasp the degree of leakage.
Incidentally, the control device S may be provided integrally with the heat pump device H, or may be provided as a part of the monitoring device K.

[Another embodiment]
(1) As shown in FIG. 9, the refrigerant leakage state determination device 100, the refrigerant leakage state determination method, and the refrigerant leakage state determination system according to the present invention include a distribution flow that divides a part of the refrigerant circulating in the refrigerant circulation path C1. Even if the configuration includes a path C2, an expansion valve V4 that expands and lowers the temperature of the branched refrigerant, and a supercooler 17 that cools the refrigerant circulating through the refrigerant circulation path C1 with the refrigerant that has passed through the expansion valve V4 and cooled. It performs its functions well.
FIG. 9 shows an example of the circuit configuration of the distribution channel C2 during cooling operation.
In addition, below, only the structure related to the distribution flow path C2 which is a different structure from the said embodiment is demonstrated, and it is assumed that the structure which is not explained is the same as the said embodiment.
As shown in FIG. 9, the upstream end of the distribution channel C2 is connected to the refrigerant circulation channel C1 between the supercooler 17 and the expansion valve V, and the downstream end is connected to the refrigerant circulation channel C1 between the accumulator 15 and the compressor 11. It is connected to the refrigerant circulation path C1 between (more specifically, the refrigerant circulation path C1 between the downstream end of the oil flow path Lo and the accumulator 15).
The distribution flow path C2 is arranged in such a manner that a flow path portion through which the refrigerant expanded by the expansion valve V4 flows passes through the inside of the supercooler 17, so that the refrigerant flows in the supercooler 17. It cools the refrigerant circulating through the circulation path C1.
Here, the value obtained by dividing the flow rate of the refrigerant guided to the distribution channel C2 by the flow rate of the refrigerant flowing through the outdoor heat exchanger 12 (the value indicated by SC in FIGS. 10 to 12) is calculated by 8% (the value indicated by SC in FIGS. 12), 4% (marked □ in Figures 10 to 12), and 0% (marked ○ in Figures 10 to 12), the relationship between the degree of supercooling at the outlet of the supercooler 17 and the refrigerant filling amount is FIG. 10 shows the relationship between the degree of subcooling at the outlet of the condenser and the amount of refrigerant charged, and FIG. 11 shows the relationship between the expansion valve opening and the amount of refrigerant charged.
According to the results, the relationship between the degree of subcooling and the amount of refrigerant charged at the outlet of the subcooler 17 changes as the amount of refrigerant charged into the distribution channel C2 changes. On the other hand, for the degree of supercooling at the outlet of the condenser (the value shown in Figure 11), the relationship between the degree of supercooling and the amount of refrigerant charged changes regardless of the change in the amount of refrigerant charged into the distribution channel C2. The relationship hasn't changed. Therefore, in a configuration including the subcooler 17, by adopting a configuration in which the degree of subcooling is derived at the outlet of the condenser, refrigerant leakage can be prevented regardless of the amount of refrigerant distributed to the distribution channel C2. It can be seen that the state can be appropriately determined.
Further, from FIG. 12, it can be seen that the amount of distribution to the distribution channel C2 has almost no effect on the relationship between the expansion valve opening degree and the refrigerant charging amount.

(2) The values of the reference average opening degree L1, threshold value R1, and threshold value R2 described above are values that change depending on the operating conditions and system configuration, and the values shown in the above embodiment are examples, and the values of the present invention are Embodiments are not limited to this value.

(3) In the above embodiment, a configuration is shown in which a small leakage state and a large leakage state are determined in addition to a medium leakage state, but a configuration that detects only a medium leakage state may be adopted. .

(4) In the above embodiment, an example was shown in which the average operating evaporator opening degree is corrected based on the degree of superheating and the average operating evaporator opening degree is corrected based on the compressor inlet pressure, but these corrections are not performed. I don't mind.

(5) In the above embodiment, the engine-driven heat pump device according to the present invention was explained as an example, but the refrigerant leakage state determination method, refrigerant leakage state determination device, and refrigerant leakage state monitoring system according to the present invention are Even a type of heat pump device can be effectively used.

(6) A small leak state is determined when the degree of supercooling calculated in the degree of supercooling calculation step is greater than zero while the degree of superheat maintenance step is being executed, and the average operating evaporator opening is If the operating evaporator average opening degree derived in the degree derivation process is less than the standard average opening degree, and the degree of superheating calculated in the degree of superheating calculation process is maintained at the standard degree of superheating, refrigerant leakage occurs. The configuration may be such that the leakage level is determined to be a slight leakage state, which is a degree of leakage that is less than a medium leakage state.

It should be noted that the configuration disclosed in the above embodiment (including other embodiments, the same applies hereinafter) can be applied in combination with the configuration disclosed in other embodiments, as long as there is no contradiction, and The embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the purpose of the present invention.

The refrigerant leakage state determination device and refrigerant leakage state monitoring system of the present invention are capable of detecting leakage, including degree of leakage, while continuing normal operation without placing restrictions on the operating state in a heat pump device having a refrigerant circulation path for circulating refrigerant. The present invention can be effectively used as a refrigerant leakage state determination method capable of determining the state, a refrigerant leakage state determination device capable of executing the determination method, and a refrigerant leakage state monitoring system.

11: Compressor 12: Outdoor heat exchanger 13: Indoor heat exchanger 100: Refrigerant leakage state determination device 200: Refrigerant leakage state monitoring system C1: Refrigerant circulation path H: Heat pump device K: Monitoring device N: Network line S: Control Device S1: Superheat degree calculation section S2: Supercooling degree calculation section S3: Operating evaporator average opening degree derivation section S5: Refrigerant leakage degree determination section V: Expansion valve

Claims (10)

A compressor that compresses refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant condensed in the condenser, and an evaporator that evaporates the refrigerant expanded in the expansion valve. A method for determining a refrigerant leakage state in a heat pump device comprising: a refrigerant circulation path that circulates refrigerant in the order described in the compressor, the condenser, the expansion valve, and the evaporator,
a degree of superheat calculation step of calculating the degree of superheat by subtracting the evaporation temperature from the refrigerant suction temperature at the inlet of the compressor;
A degree of supercooling calculation step of calculating the degree of supercooling by subtracting the refrigerant temperature at the condenser outlet from the condensation temperature;
In the case where there is at least one evaporator, a value obtained by converting the expansion valve opening degree based on the capacity ratio of the evaporator with respect to the evaporator in operation and the expansion valve corresponding to the evaporator. an operating evaporator average opening degree derivation step of deriving an operating evaporator average opening degree as an average value;
A superheat degree maintenance step of maintaining the superheat degree at a reference superheat degree during normal operation;
The operating evaporator in which the supercooling degree calculated in the supercooling degree calculation step is zero in the state in which the superheat degree maintaining step is executed, and the operating evaporator average opening degree deriving step The average opening exceeds the standard average opening which exceeds the average opening which is the average opening of the operating evaporator under rated conditions during normal operation by a predetermined value, and is the maximum value of the average opening of the operating evaporator. Refrigerant leakage degree determination that determines that the degree of refrigerant leakage is in a moderate leakage state when the degree of superheating calculated in the superheating degree calculation step is maintained at the reference degree of superheating when the opening degree is less than the maximum average opening degree. A method for determining a refrigerant leakage state, including a process. The refrigerant leakage degree determination step includes:
When the degree of superheating is maintained, the degree of supercooling calculated in the degree of supercooling calculation step is greater than zero, and the degree of supercooling calculated in the degree of supercooling calculation step is greater than zero, and When the average opening of the operating evaporator is less than the maximum average opening and the degree of superheat calculated in the degree of superheat calculation step is maintained at the standard degree of superheat, the degree of refrigerant leakage is medium leakage. 2. The refrigerant leak state determination method according to claim 1, wherein the refrigerant leak state is determined to be a slight leak state, which includes no leak, the degree of leak being smaller than that of the refrigerant leak state. The refrigerant leakage degree determination step includes:
In the state in which the superheat degree maintenance step is executed, the degree of supercooling calculated in the supercooling degree calculation step is zero, and the operating evaporator is derived in the operating evaporator average opening degree deriving step. When the average degree of opening is the maximum average degree of opening and the degree of superheat calculated in the degree of superheat calculation step is greater than the reference degree of superheat, the degree of leakage of the refrigerant is greater than the degree of leakage in the medium leakage state. The refrigerant leakage state determination method according to claim 1, wherein the refrigerant leakage state determination method is determined to be a leakage state to a certain extent. The refrigerant leakage degree determination step includes:
The operating evaporator in which the supercooling degree calculated in the supercooling degree calculation step is zero in the state in which the superheat degree maintaining step is executed, and the operating evaporator average opening degree deriving step When the average opening is the maximum average opening and the degree of superheat calculated in the degree of superheat calculation step is greater than the reference degree of superheat, the degree of leakage of the refrigerant is greater than the degree of leakage in the medium leakage state. 3. The refrigerant leak state determination method according to claim 2, wherein the refrigerant leak state determination method determines that the refrigerant leak state is to a certain extent. The refrigerant leakage degree determination step includes:
The combination of the values of the degree of supercooling, the average opening of the operating evaporator, and the degree of superheat is other than the combination of values specified in the medium leakage state, the small leakage state, and the large leakage state. 5. The refrigerant leak state determination method according to claim 4, wherein if the heat pump device is in an operating state different from the normal operation, the heat pump device is excluded from the determination of the degree of leakage. The refrigerant leakage degree determination step includes:
Any one of claims 1 to 5, wherein the operating evaporator average opening degree derived in the operating evaporator average opening degree deriving step is corrected to a higher side as the evaporation pressure that is the inlet pressure of the compressor increases. The refrigerant leakage state determination method described in . The refrigerant leakage degree determination step includes:
From the operating evaporator average opening degree and evaporation pressure derived in the operating evaporator average opening degree derivation step, a leakage rate is derived by dividing the refrigerant leakage amount by the regular filling amount without refrigerant leakage. The refrigerant leakage state determination method according to any one of claims 1 to 6. The refrigerant leakage degree determination step includes:
Refrigerant leakage state determination according to any one of claims 1 to 7, wherein the average operating evaporator opening degree derived in the average operating evaporator opening degree deriving step is corrected to a higher side as the degree of superheating increases. Method. A compressor that compresses refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant condensed in the condenser, and an evaporator that evaporates the refrigerant expanded in the expansion valve. A refrigerant leakage state determination device in a heat pump device comprising: a refrigerant circulation path that circulates refrigerant in the order described in the compressor, the condenser, the expansion valve, and the evaporator,
a degree of superheat calculation unit that calculates the degree of superheat by subtracting the evaporation temperature from the refrigerant suction temperature at the compressor inlet;
a supercooling degree calculation unit that calculates a supercooling degree by subtracting the refrigerant temperature at the condenser outlet from the condensing temperature;
In the case where there is at least one evaporator, a value obtained by converting the expansion valve opening degree based on the capacity ratio of the evaporator with respect to the evaporator in operation and the expansion valve corresponding to the evaporator. an operating evaporator average opening degree derivation unit that derives an operating evaporator average opening degree as an average value;
a superheat degree maintenance part that maintains the superheat degree at a reference superheat degree during normal operation;
the operating evaporator in which the supercooling degree calculated by the supercooling degree calculation unit is zero in a state in which the superheat degree maintaining unit is executed, and the operating evaporator average opening degree deriving unit derives the operating evaporator; The average opening exceeds the standard average opening which exceeds the average opening which is the average opening of the operating evaporator under rated conditions during normal operation by a predetermined value, and is the maximum value of the average opening of the operating evaporator. Refrigerant leakage degree determination that determines that the degree of refrigerant leakage is in a moderate leakage state when the degree of superheating calculated by the superheating degree calculation unit is maintained at the reference degree of superheating when the opening degree is less than the maximum average opening degree. A refrigerant leak state determination device having a section. In addition to comprising the refrigerant leakage state determining device according to claim 9,
comprising a monitoring device electrically connected to the heat pump device through a network line,
A refrigerant leakage state monitoring system, wherein the monitoring device is configured to monitor the degree of leakage of the refrigerant.

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