JP7034381B2 - Airtightness evaluation device and airtightness determination method - Google Patents

Description

The present invention relates to a technique for evaluating airtightness in a refrigeration cycle system.

Refrigeration cycle systems such as air conditioners and refrigeration devices that use refrigeration cycles are widely used all over the world and are indispensable to the lives of modern people. However, the refrigerant enclosed in the refrigeration cycle has a greenhouse effect and is flammable, and the adverse effect of leakage is regarded as a problem.
In Japan, in April 2015, the "Act on the Rational Use of Refrigerants and the Appropriate Management of Refrigerants" was enforced, and inspections and records regarding refrigerant leaks and reports at the time of leaks became mandatory.

When filling the refrigerant during installation and repair of the refrigeration cycle system, it is necessary to confirm that there is no leakage in the refrigeration cycle before filling.
The nitrogen pressure leak test is widely used as a method for determining the presence or absence of a leak. In the nitrogen pressure leakage test, nitrogen is filled in the refrigeration cycle before filling with the refrigerant and pressurized, and the airtightness of the refrigeration cycle is evaluated based on the pressure change up to a certain period of time. Then, if the airtightness is higher than the standard, it is determined that there is no leakage.

In Patent Document 1, a tube inserter for connecting a nitrogen cylinder is used to improve the work efficiency of the nitrogen pressure leak test.

Japanese Unexamined Patent Publication No. H07-286932

In the nitrogen pressure leak test, it is necessary to use a pressure gauge that can measure high pressure in order to measure the pressure of pressurized nitrogen. A pressure gauge capable of measuring a high pressure has a low resolution, and it is difficult to measure a small change in pressure. When the amount of leakage is very small in the nitrogen pressure leakage test, it takes time for the pressure to drop enough to be clearly measured by the pressure gauge. Therefore, in the nitrogen pressure leakage test, it takes a long time, such as one day, to evaluate the airtightness after the nitrogen is sealed and pressurized.
In Patent Document 1, the time until the start of the pressurized leak test can be reduced, but the time of the nitrogen pressurized leak test itself, which accounts for most of the total working time in a series, cannot be shortened.
An object of the present invention is to enable evaluation of airtightness in a refrigeration cycle system by a simple method.

The airtightness evaluation device according to the present invention is
A dividing part that divides the flow path constituting the steam compression type refrigeration cycle by a valve to form a plurality of flow path spaces, and a divided portion.
A differential pressure measuring unit that measures the differential pressure of two flow path spaces among the plurality of flow path spaces formed by the divided section, and a differential pressure measuring unit.
It is provided with an evaluation unit for evaluating the airtightness of the two flow path spaces based on the differential pressure measured by the differential pressure measuring unit.

In the present invention, the flow paths constituting the refrigeration cycle are divided, and the airtightness of the two flow path spaces is evaluated by the differential pressure between the two flow path spaces. In order to measure the differential pressure between the two flow path spaces, a pressure gauge capable of measuring a high pressure is not required, and a differential pressure gauge capable of measuring a small differential pressure is used. Therefore, it is possible to evaluate the airtightness without waiting for a long time.

The block diagram of the air conditioning system 11 which is the refrigeration cycle system 10 which concerns on Embodiment 1. FIG. The functional block diagram of the unit control apparatus 29 and the external control apparatus 70 which concerns on Embodiment 1. FIG. The flowchart which shows the operation of the airtightness evaluation apparatus 100 which concerns on Embodiment 1. The figure which shows the connection state of the differential pressure gauge 80 of the step S103 which concerns on Embodiment 1. FIG. The figure which shows the connection state of the differential pressure gauge 80 of the step S109 which concerns on Embodiment 1. FIG. The figure which shows the connection state of the differential pressure gauge 80 of the step S112 which concerns on Embodiment 1. FIG. The block diagram of the air conditioning system 11 which is the refrigeration cycle system 10 which concerns on Embodiment 2. FIG. The flowchart which shows the operation of the airtightness evaluation apparatus 100 which concerns on Embodiment 2. The figure which shows the connection state of the differential pressure gauge 80 of the step S204 which concerns on Embodiment 2. FIG.

Embodiment 1.
*** Explanation of configuration ***
The configuration of the refrigeration cycle system 10 according to the first embodiment will be described with reference to FIG.
In FIG. 1, the air conditioning system 11 is shown as the refrigeration cycle system 10. The air conditioning system 11 is a system equipped with a steam compression type refrigeration cycle installed in places such as buildings, apartment houses, and commercial facilities, and is a system capable of cooling operation and heating operation.

<Air conditioning system 11>
The air conditioning system 11 includes an outdoor unit 20, an indoor unit 30, and an indoor unit 40 that form a steam compression type refrigeration cycle. The outdoor unit 20 is connected to the indoor unit 30 and the indoor unit 40 by liquid pipes 51, 52, 53 and gas pipes 61, 62, 63, which are pipes for flowing a refrigerant. The liquid pipes 52 and 53 are branched from the liquid pipe 51 at the liquid pipe branch portion 54. Further, the gas pipes 62 and 63 are branched from the gas pipe 61 at the gas pipe branch portion 64.
The air conditioning system 11 transmits an operation operation command to the unit control device 29 mounted on the outdoor unit 20, and is an external control device for monitoring the operating state of the outdoor unit 20, the indoor unit 30, and the indoor unit 40. 70 is provided. As a specific example, the external control device 70 is configured by a notebook type PC (Personal Computer).
The air conditioning system 11 includes a differential pressure gauge 80. The differential pressure gauge 80 includes connection ports 81 and 82, and measures the differential pressure in two spaces to which the connection ports 81 and 82 are connected.

<Outdoor unit 20>
The outdoor unit 20 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an outdoor blower 24, a connection port 25 with a valve, a connection port 26 with a valve, a connection port 27 and a connection port 28, and a unit. A control device 29 is provided.

The compressor 21 is a type of compressor having a variable operating capacity that sucks and compresses a refrigerant to bring it into a high temperature and high pressure state.
The four-way valve 22 is a valve for switching the flow direction of the refrigerant, and has first to fourth ports. In the four-way valve 22, the first port is connected to the discharge side of the compressor 21, the second port is connected to the outdoor heat exchanger 23, the third port is connected to the suction side of the compressor 21, and the fourth port is connected to the connection port 26 with a valve. .. In the four-way valve 22, the first port and the second port communicate with each other, and at the same time, the third port and the fourth port communicate with each other (the state shown by the solid line in FIG. 1), and the first port and the fourth port communicate with each other. At the same time, the setting can be switched to a state in which the second port and the third port communicate with each other (the state shown by the broken line in FIG. 1).
The outdoor heat exchanger 23 is a heat exchanger that exchanges heat between the outside air and the refrigerant and exhausts heat. As a specific example, the outdoor heat exchanger 23 is a cross-fin type fin-and-tube heat exchanger composed of a heat transfer tube and a large number of fins.
The outdoor blower 24 is a blower whose rotation speed can be changed to supply air to the outdoor heat exchanger 23. The outdoor blower 24 is, as a specific example, a propeller fan.

The connection port 25 with a valve and the connection port 26 with a valve have three ports, a first port, a second port, and a third port, and each port communicates with each other. In the connection port 25 with a valve, the first port is connected to the outdoor heat exchanger 23 and the second port is connected to the liquid pipe 51. In the connection port 26 with a valve, the first port is connected to the four-way valve 114 and the second port is connected to the gas pipe 61.
The third port of the connection port 25 with a valve and the connection port 26 with a valve can be connected to the connection port 81 or the connection port 82 of the differential pressure gauge 80, and is used for airtightness evaluation. The third port is provided with a valve core, and when the instrument is not connected to the third port, no fluid flows out from the third port.
The connection port 25 with a valve and the connection port 26 with a valve are provided with a valve that can open and close at least one of the first port and the second port.

The connection port 27 and the connection port 28 include three ports, a first port, a second port, and a third port, and each port communicates with each other. As for the connection port 27, the first port is connected to the discharge side of the compressor 21, and the second port is connected to the four-way valve 22. As for the connection port 28, the first port is connected to the suction side of the compressor 21, and the second port is connected to the four-way valve 22.
The third port of the connection port 27 and the connection port 28 can be connected to the connection port 81 or the connection port 82 of the differential pressure gauge 80, and is used for the airtightness evaluation. The third port is provided with a valve core, and when the instrument is not connected to the third port, no fluid flows out from the third port.

The unit control device 29 is a device that controls the operation of the outdoor unit 20. As a specific example, the unit control device 29 is configured by a microcomputer.

The outdoor unit 20 includes temperature sensors 211 to 215. The temperature sensor 211 measures the temperature of the refrigerant on the suction side of the compressor 21. The temperature sensor 212 measures the refrigerant temperature on the discharge side of the compressor 21. The temperature sensor 213 measures the refrigerant temperature in the central portion of the outdoor heat exchanger 23. The temperature sensor 214 measures the refrigerant temperature on the liquid side of the outdoor heat exchanger 23. The temperature sensor 215 is provided at the air intake port of the outdoor heat exchanger 23, and measures the outside air temperature.

<Indoor unit 30 and indoor unit 40>
The indoor unit 30 includes a decompression mechanism 31, an indoor heat exchanger 32, an indoor blower 33, a connection port 34 with a valve, and a valve 35.
The indoor unit 40 has the same configuration as the indoor unit 30, and includes a decompression mechanism 41, an indoor heat exchanger 42, an indoor blower 43, a connection port 44 with a valve, and a valve 45.

The decompression mechanisms 31 and 41 are mechanisms that control the flow rate of the refrigerant by changing the opening degree.
The indoor heat exchangers 32 and 42 are heat exchangers that exchange heat between the indoor air and the refrigerant. As a specific example, the indoor heat exchanger 32 is a cross-fin type fin-and-tube heat exchanger composed of a heat transfer tube and a large number of fins.
The indoor blowers 33 and 43 are blowers whose rotation speed can be changed to supply air to the indoor heat exchangers 32 and 42. The indoor blowers 33 and 43 are, as a specific example, a propeller fan.

The connection port 34 with a valve and the connection port 44 with a valve have three ports, a first port, a second port, and a third port, and each port communicates with each other. In the connection port 34 with a valve, the first port is connected to the indoor heat exchanger 32 and the second port is connected to the gas pipe 62. In the connection port 44 with a valve, the first port is connected to the indoor heat exchanger 42 and the second port is connected to the gas pipe 63.
The third port of the connection port 34 with a valve and the connection port 44 with a valve can be connected to the connection port 81 or the connection port 82 of the differential pressure gauge 80, and is used for airtightness evaluation. The third port is provided with a valve core, and when the instrument is not connected to the third port, no fluid flows out from the third port.
The connection port 34 with a valve and the connection port 44 with a valve are provided with a valve that can open and close at least one of the first port and the second port.

One port of the valve 35 is connected to the decompression mechanism 31, and the other port is connected to the liquid pipe 52. One port of the valve 45 is connected to the decompression mechanism 41, and the other port is connected to the liquid pipe 53. The valve 35 and the valve 45 can open and close the flow path.

The indoor unit 30 includes temperature sensors 311 to 313. The indoor unit 40 includes temperature sensors 411 to 413. The temperature sensors 311, 411 measure the refrigerant temperature on the liquid side of the indoor heat exchangers 32 and 42. The temperature sensors 312 and 412 measure the refrigerant temperature on the gas side of the indoor heat exchangers 32 and 42. The temperature sensors 313 and 413 are provided at the air intake ports of the indoor heat exchangers 32 and 42, and measure the air temperature at the installation location of the indoor heat exchangers 32 and 42.

<Unit control device 29 and external control device 70>
The functional configuration of the unit control device 29 and the external control device 70 according to the first embodiment will be described with reference to FIG.

The unit control device 29 includes a measurement unit 291, a calculation unit 292, a control unit 293, a unit communication unit 294, a unit storage unit 295, a division unit 296, a differential pressure measurement unit 297, and a reference value calculation unit 298. And an evaluation unit 299. The division unit 296, the differential pressure measurement unit 297, the reference value calculation unit 298, and the evaluation unit 299 are the functions of the airtightness evaluation device 100.
Here, the function of the airtightness evaluation device 100 is mounted on the unit control device 29. However, the function of the airtightness evaluation device 100 may be provided as a device different from the unit control device 29.

The measuring unit 291 acquires various quantities measured by each temperature sensor (temperature sensors 211 to 215, temperature sensors 311 to 313, temperature sensors 411 to 413) and the like. The calculation unit 292 performs calculations for determining various control operations such as calculating the saturation temperature of the detected pressure based on the various quantities acquired by the measurement unit 291. The control unit 293 controls devices such as a compressor 21, a four-way valve 22, decompression mechanisms 31, 41, and blowers (outdoor blower 24 and indoor blower 33, 43) based on the result calculated by the calculation unit 292. .. The unit communication unit 294 receives information input from the outside and outputs information to the outside by means of communication means such as a telephone line, a LAN (Local Area Network) line, and wireless communication means. The unit communication unit 294 receives, for example, input of various commands such as ON / OFF of cooling operation and ON / OFF of heating operation from a remote controller. Further, the unit communication unit 294 communicates information such as a measured value and a control value of the device with the external control device 70, for example. The unit storage unit 295 is composed of a semiconductor memory or the like, and stores a set value or the like used for operation.

The airtightness evaluation device 100 evaluates the airtightness of the refrigeration cycle in the air conditioning system 11. That is, the airtightness evaluation device 100 evaluates whether or not a fluid such as a refrigerant does not leak from the refrigeration cycle in the air conditioning system 11.
The division unit 296 divides the flow path constituting the refrigeration cycle in the air conditioning system 11 by a valve to form a plurality of flow path spaces. The differential pressure measuring unit 297 measures the differential pressure of two flow path spaces out of the plurality of flow path spaces formed by the dividing unit 296. The reference value calculation unit 298 calculates a reference value as a criterion for determining the differential pressure based on the ambient temperature of the two flow path spaces. The evaluation unit 299 evaluates the airtightness of the two flow path spaces based on the reference value calculated by the reference value calculation unit 298 and the differential pressure measured by the differential pressure measurement unit 297.

The external control device 70 includes an input unit 71, an external communication unit 72, a storage unit 73, and a display unit 74.
The input unit 71 receives an input such as an operation command of the air conditioning system 11 from the operator. The external communication unit 72 receives data from the outside via communication means such as a telephone line, a LAN line, and wireless, and outputs the data to the outside. As a specific example, the external communication unit 72 transmits an operation command or the like received by the input unit 71 to the unit control device 29, and receives operation data such as pressure and temperature from the unit control device 29. The storage unit 73 is composed of a semiconductor memory or the like, and stores the set value or the like of the air conditioning system 11. The display unit 74 is composed of an LCD (Liquid Crystal Display) or the like, and displays the operating state of the air conditioning system 11.

*** Explanation of operation ***
The operation of the airtightness evaluation device 100 according to the first embodiment will be described with reference to FIG.
The operation of the airtightness evaluation device 100 according to the first embodiment corresponds to the airtightness determination method according to the first embodiment.

Here, a case where a fluid such as nitrogen is enclosed in a refrigeration cycle to evaluate airtightness when the air conditioning system 11 is installed will be described. Therefore, as a premise of the process of FIG. 3, a fluid such as nitrogen is sealed in the refrigeration cycle of the air conditioning system 11.

In step S101, the connection port 81 of the differential pressure gauge 80 is connected to the third port of the connection port 26 with a valve, and the connection port 82 is connected to the third port of the connection port 27 by the worker.
In step S102, the split portion 296 opens the valves of the connection ports 25, 26, 34, 44 with valves and the valves 35, 45, and waits until a certain period of time elapses. By opening the valves of the connection ports 25, 26, 34, 44 with valves and the valves 35, 45, the outdoor unit 20 and the indoor units 30, 40 are connected, and the enclosed fluid enters the refrigeration cycle. You will be able to move freely. Therefore, after a certain period of time elapses in this state, the pressure in the refrigeration cycle becomes constant.
In step S103, the division unit 296 closes the first port, which is the port on the outdoor unit 20 side of the connection ports 25 and 26 with valves, and waits until a certain period of time elapses. By closing the first port of the connection ports 25 and 26 with valves, as shown in FIG. 4, the flow path space (flow path space shown by the broken line) on the outdoor unit 20 side in the refrigeration cycle and the refrigeration cycle. It is separated from the other flow path space (flow path space shown by the solid line) in the above, and the fluid cannot move. In FIG. 4, the valve shown in white indicates that the valve is open, and the valve shown in black indicates that the valve is closed. In other figures, opening and closing of valves are similarly represented. Therefore, when the airtightness from either the flow path space on the outdoor unit 20 side in the refrigeration cycle or the other flow path space in the refrigeration cycle is low, that is, when the refrigerant leaks, the pressure in the flow path space is low. Gradually decreases.

In step S104, the differential pressure measuring unit 297 measures the differential pressure with the differential pressure gauge 80. That is, the differential pressure measuring unit 297 measures the differential pressure between the flow path space on the outdoor unit 20 side in the refrigeration cycle and the other flow path space in the refrigeration cycle. The reference value calculation unit 298 calculates a reference value as a criterion for determining the differential pressure based on the temperature measured by the temperature sensors 211 to 215, 311 to 313, 411 to 413. The calculation method of the reference value will be described later. Then, the evaluation unit 299 determines whether or not there is a differential pressure larger than the reference value. If there is no differential pressure, the evaluation unit 299 advances the process to step S105. On the other hand, if there is a differential pressure, the evaluation unit 299 advances the process to step S106.
In step S105, the evaluation unit 299 determines that no fluid such as nitrogen is leaking from either the flow path space on the outdoor unit 20 side in the refrigeration cycle or the other flow path space in the refrigeration cycle. That is, the evaluation unit 299 determines that there is no fluid leakage from the refrigeration cycle and the airtightness is ensured.

In step S106, the evaluation unit 299 determines which pressure is lower, the flow path space on the outdoor unit 20 side in the refrigeration cycle or the other flow path space in the refrigeration cycle. When the pressure in the flow path space on the outdoor unit 20 side in the refrigeration cycle is low, the evaluation unit 299 proceeds to the process in step S107. On the other hand, the evaluation unit 299 advances the process to step S108 when the pressure in the other flow path spaces in the refrigeration cycle is low.
In step S107, the evaluation unit 299 determines that the fluid is leaking from the flow path space of the outdoor unit 20.

In step S108, the connection port 81 of the differential pressure gauge 80 is connected to the third port of the connection port 26 with a valve, and the connection port 82 is connected to the third port of the connection port 25 with a valve by the worker.
In step S109, the split portion 296 closes the first port, which is a port on the indoor units 30 and 40 sides of the connection ports 34 and 44 with valves, and the valves 35 and 45, and waits until a certain period of time elapses. As shown in FIG. 5, a liquid pipe connecting the outdoor unit 20 and the indoor units 30 and 40 in the refrigeration cycle by closing the first port of the connection ports 34 and 44 with valves and the valves 35 and 45. The flow path spaces of the 51, 52, 53 and the gas pipes 61, 62, 63 are the flow path space of the liquid pipes 51, 52, 53 (the flow path space shown by the broken line) and the gas pipes 61, 62, 63. It is separated from the flow path space (flow path space shown by the solid line).

In step S110, the differential pressure measuring unit 297 measures the differential pressure with the differential pressure gauge 80. That is, the differential pressure measuring unit 297 measures the differential pressure between the flow path spaces of the liquid pipes 51, 52, 53 and the flow path spaces of the gas pipes 61, 62, 63. The evaluation unit 299 determines whether or not there is a differential pressure larger than the reference value. Here, the reference value calculation unit 298 may calculate the reference value again, or may use a preset fixed value as the reference value. If there is no differential pressure, the evaluation unit 299 advances the process to step S111. On the other hand, if there is a differential pressure, the evaluation unit 299 advances the process to step S114.

In step S111, the connection port 81 of the differential pressure gauge 80 is connected to the third port of the connection port 44 with a valve, and the connection port 82 is connected to the third port of the connection port 34 with a valve by the worker.
In step S112, the split portion 296 opens the first port which is a port on the outdoor unit 20 and 30 side of the connection port 34 and 44 with a valve, and the port on the gas pipe 62 and 63 side of the connection port 34 and 44 with a valve. Close the second port and wait until a certain period of time elapses. By closing the second port, which is the port on the gas pipes 62, 63 side of the connection ports 34, 44 with valves, as shown in FIG. 6, the flow path space of the indoor unit 30 and the indoor unit 40 in the refrigeration cycle is reduced. , The flow path space of the indoor unit 30 (the flow path space shown by the broken line) and the flow path space of the indoor unit 40 (the flow path space shown by the solid line) are separated.

In step S113, the differential pressure measuring unit 297 measures the differential pressure with the differential pressure gauge 80. That is, the differential pressure measuring unit 297 measures the differential pressure between the flow path space of the indoor unit 30 and the flow path space of the indoor unit 40. The evaluation unit 299 determines whether or not there is a differential pressure larger than the reference value. Here, the reference value calculation unit 298 may calculate the reference value again, or may use a preset fixed value as the reference value. If there is no differential pressure, the evaluation unit 299 returns the process to step S101 and evaluates the airtightness again. On the other hand, if there is a differential pressure, the evaluation unit 299 advances the process to step S117.

In step S114, the evaluation unit 299 determines which pressure is lower, the flow path space of the liquid pipes 51, 52, 53 or the flow path space of the gas pipes 61, 62, 63. When the pressure in the flow path space of the liquid pipes 51, 52, and 53 is low, the evaluation unit 299 proceeds to the process in step S115. On the other hand, when the pressure in the flow path space of the gas pipes 61, 62, 63 is low, the evaluation unit 299 proceeds to the process in step S116.
In step S115, the evaluation unit 299 determines that the fluid is leaking from the flow path space of the liquid pipes 51, 52, 53. On the other hand, in step S116, the evaluation unit 299 determines that the fluid is leaking from the flow path space of the gas pipes 61, 62, 63.

In step S117, the evaluation unit 299 determines which pressure is lower, the flow path space of the indoor unit 30 or the flow path space of the indoor unit 40. When the pressure in the flow path space of the indoor unit 30 is low, the evaluation unit 299 proceeds to the process in step S118. On the other hand, when the pressure in the flow path space of the indoor unit 40 is low, the evaluation unit 299 proceeds to the process in step S119.
In step S118, the evaluation unit 299 determines that the fluid is leaking from the flow path space of the indoor unit 30. On the other hand, in step S119, the evaluation unit 299 determines that the fluid is leaking from the flow path space of the indoor unit 40.

The method of calculating the reference value in step S104 will be described. Further, a determination method using the reference values in steps S104 and S106 will also be described.
The outdoor unit 20 and the indoor units 30 and 40 are often installed in different spaces. At this time, due to the difference in atmospheric temperature, a differential pressure may occur regardless of the presence or absence of leakage. Therefore, the reference value is calculated using the temperature measured by the temperature sensors 211 to 215, 311 to 313, 411 to 413.

For a gas that behaves close to an ideal gas, such as nitrogen, the temperature and pressure follow Boyle-Charles' law. The Boyle-Charles law is given by equation (1) using a pressure P, a volume V, a temperature T, and a constant k.
Equation (1) P = k · T / V

The pressure in the pressure equalizing state in step 102 is P0, the temperature of the gas in the pressure equalizing state is T0, the outside air temperature is Tout, and the room temperature is Tin. For example, assuming that the outside air temperature is higher than the room temperature as in summer, the equation (2) holds. The outside air temperature Tout is measured by the temperature sensor 215, and the room temperature Tin is measured by the temperature sensors 313 and 413.
Equation (2) Tin <T0 <Tout

When the temperature of the gas inside the outdoor unit 20 and the indoor units 30 and 40 changes depending on the atmospheric temperature, what is the pressure Pout in the outdoor unit 20 and the pressure Pin in the indoor units 30 and 40 from the equation (1)? The pressure changes from the pressure P0 in the pressure equalizing state in step S102 to the values of the equations (3) and (4) at the maximum.
Equation (3) Pout = P0 · Tout / T0
Equation (4) Pin = P0 · Tin / T0
Therefore, even if there is no leakage, the differential pressure ΔP represented by the equation (5) is generated due to the influence of the atmospheric temperature.
Equation (5) ΔP = Pout-Pin = P0 · (Tout-Tin) / T0

Since ΔP is maximized in the equation (5) when T0 = Tin from the equation (2), the maximum value ΔPmax of the differential pressure generated by the atmospheric temperature is given by the equation (6).
Equation (6) ΔPmax = P0 ・ (Tout-Tin) / Tin
The reference value calculation unit 298 calculates using this maximum value ΔPmax as a reference value.

When the differential pressure ΔPs indicated by the differential pressure gauge 80 satisfies the equation (7), the evaluation unit 299 determines that there is no differential pressure. Further, the evaluation unit 299 determines that leakage occurs from the outdoor unit 20 side when the differential pressure ΔPs satisfies the equation (8), and when the differential pressure ΔPs satisfies the equation (9), the indoor units 30 and 40. Judged as a leak from the side.
Equation (7) 0 ≦ ΔPs ≦ ΔPmax
Equation (8) ΔPs <0
Equation (9) ΔPmax <ΔPs

When the indoor temperature Tin is higher than the outside air temperature Tout as in winter, ΔPmax is given by the equation (10).
Equation (10) ΔPmax = P0 · (Tout-Tin) / Tout
The reference value calculation unit 298 calculates using this maximum value ΔPmax as a reference value.

When the differential pressure ΔPs indicated by the differential pressure gauge 80 satisfies the equation (11), the evaluation unit 299 determines that there is no differential pressure. Further, the evaluation unit 299 determines that leakage occurs from the outdoor unit 20 side when the differential pressure ΔPs satisfies the equation (12), and when the differential pressure ΔPs satisfies the equation (13), the indoor units 30 and 40. Judged as a leak from the side.
Equation (11) ΔPmax≤ΔPs≤0
Equation (12) ΔPs <ΔPmax
Equation (13) 0 <ΔPs

In step S110 and step S113, the reference value can be calculated by the same method based on the atmospheric temperature of the two flow path spaces for measuring the differential pressure. However, in step S110 and step S113, there is a possibility that two flow path spaces for measuring the differential pressure are installed in spaces having the same ambient temperature. When the atmosphere temperatures of the two flow path spaces for measuring the differential pressure are the same, the reference value may not be calculated and a preset fixed value may be used as the reference.

*** Effect of Embodiment 1 ***
As described above, the airtightness evaluation device 100 according to the first embodiment evaluates the airtightness of the two flow path spaces by dividing the flow paths constituting the refrigeration cycle and using the differential pressure between the two flow path spaces. In order to measure the differential pressure between the two flow path spaces, a pressure gauge capable of measuring a high pressure is not required, and a differential pressure gauge capable of measuring a small differential pressure can be used. Therefore, it is possible to evaluate the airtightness without waiting for a long time.

If a leak is confirmed by the test, it is necessary to identify and repair the leaked part. Conventionally, a method of spraying a test solution and determining whether or not bubbles are formed has been used to identify a leak location. Based on the experience of the operator, the test liquid is sprayed in order from the place where the leakage frequency is high, for example, the pipe joint. Therefore, the work time to identify the leak location largely depends on the chance and the experience value of the worker.
The airtightness evaluation device 100 according to the first embodiment further divides the flow path space determined to have a fluid leak to form two flow path spaces, and evaluates the airtightness by the differential pressure. This makes it possible to easily identify the location where the fluid leaks.

*** Other configurations ***
<Modification 1>
In the first embodiment, a case where the airtightness is evaluated at the time of installation of the air conditioning system 11 has been described. However, the airtightness evaluation device 100 can also evaluate the airtightness after the operation of the air conditioning system 11 is started.
When the airtightness is evaluated after the operation of the air conditioning system 11 is started, the refrigerating cycle is filled with a refrigerant. Therefore, in this case, it is not necessary to enclose a fluid such as nitrogen in the refrigeration cycle. Other processes are the same as when the airtightness is evaluated when the air conditioning system 11 is installed.

<Modification 2>
In the first embodiment, it has been described that the connection of the differential pressure gauge 80 is performed by an operator. However, the connection of the differential pressure gauge 80 may be realized by the control of the airtightness evaluation device 100.
As a specific example, the connection port 81 and the connection port 82 of the differential pressure gauge 80 are the connection ports 25 and 26 with valves, the connection ports 27 and 28, and the third ports of the connection ports 34 and 44 with valves, respectively. It shall be connected by piping. A valve is provided in the middle of each pipe connecting the connection port 81 and the connection port 82, the connection ports 25 and 26 with valves, the connection ports 27 and 28, and the third port of the connection ports 34 and 44 with valves. Normally, the valves of each pipe should be closed. Then, if necessary, the differential pressure gauge 80 can be connected to each position of the refrigeration cycle by opening the valve provided in the middle of the piping under the control of the airtightness evaluation device 100.

<Modification 3>
In the first embodiment, it has been described that the division portion 296 divides the flow path constituting the refrigeration cycle by a valve to form a plurality of flow path spaces. However, the valve may be opened and closed by an operator, and the flow paths constituting the refrigeration cycle may be divided to form a plurality of flow path spaces.

<Modification example 4>
In the first embodiment, the air conditioning system 11 is provided with the airtightness evaluation device 100. However, the airtightness evaluation device 100 may be provided separately from the air conditioning system 11. For example, the airtightness evaluation device 100 may be realized as a cloud system and may be connected to the air conditioning system 11 via a communication path such as the Internet.

<Modification 5>
The air conditioning system 11 may be configured to allow the refrigeration cycle to be more finely separated by providing more valves. This makes it possible to specify the leak position of the fluid in more detail. In this case, it is necessary to provide a connection port for connecting the differential pressure gauge 80 in each flow path space formed by dividing the refrigeration cycle.

<Modification 6>
In the first embodiment, the refrigeration cycle system 10 is an air conditioning system 11. However, the refrigeration cycle system 10 is not limited to the air conditioning system 11, and may be a refrigeration system such as a refrigerator.

Embodiment 2.
The second embodiment is different from the first embodiment in that the differential pressure is measured for the flow path spaces of the two outdoor units 20 having the same capacity and the airtightness of the flow path spaces of the two outdoor units 20 is evaluated. In the second embodiment, these different points will be described, and the same points will be omitted.

*** Explanation of configuration ***
The configuration of the refrigeration cycle system 10 according to the second embodiment will be described with reference to FIG. 7.
In FIG. 7, the air conditioning system 11 is shown as the refrigeration cycle system 10 as in the first embodiment.

The air conditioning system 11 includes a pair of an outdoor unit 20A, an indoor unit 30A, and an indoor unit 40A forming a steam compression type refrigeration cycle A, and an outdoor unit 20B, an indoor unit 30B, and an indoor unit forming a steam compression type refrigeration cycle B. It is equipped with a set with the machine 40B.
The outdoor unit 20A and the outdoor unit 20B have the same configuration as the outdoor unit 20 according to the first embodiment. The outdoor unit 20A and the outdoor unit 20B are outdoor units having the same capacity. The indoor unit 30A and the indoor unit 30B have the same configuration as the indoor unit 30 according to the first embodiment, and the indoor unit 40A and the indoor unit 40B have the same configuration as the indoor unit 40 according to the first embodiment.
In the following description, "A" is added after the reference numerals for the components of the outdoor unit 20A, the indoor unit 30A, and the indoor unit 40A, and the components of the outdoor unit 20B, the indoor unit 30B, and the indoor unit 40B are described. , "B" is added after the code to distinguish.

*** Explanation of operation ***
The operation of the airtightness evaluation device 100 according to the second embodiment will be described with reference to FIG.
The operation of the airtightness evaluation device 100 according to the second embodiment corresponds to the airtightness evaluation method according to the second embodiment.

Here, a case where the airtightness of the outdoor unit 20A and the outdoor unit 20B is evaluated will be described.

In step S201, the connection port 81 of the differential pressure gauge 80 is connected to the third port of the connection port 27A, and the connection port 82 is connected to the third port of the connection port 27B by the worker. In step S202, the worker connects the third port of the connection port 25A with a valve and the third port of the connection port 25B with a valve by piping.
In step S203, the split portion 296 opens the first port, which is the port on the outdoor unit 20 side of the connection ports 25A, 25B, 26A, and 26B with valves, and waits until a certain period of time elapses.

In step S204, the split portion 296 closes the first port, which is the port on the outdoor unit side of the connection ports 25A, 25B, 26A, and 26B with valves, and waits until a certain period of time elapses. By closing the first port, which is the port on the outdoor unit side of the connection ports 25A, 25B, 26A, and 26B with valves, as shown in FIG. 9, the flow path space on the outdoor unit 20A side in the refrigeration cycle A and the flow path space on the outdoor unit 20A side. It is separated from the other flow path spaces in the refrigeration cycle A, and the fluid cannot move. Similarly, the flow path space on the outdoor unit 20B side in the refrigeration cycle B and the other flow path spaces in the refrigeration cycle B are separated, and the fluid cannot move.

In step S205, the differential pressure measuring unit 297 measures the differential pressure with the differential pressure gauge 80. That is, the differential pressure measuring unit 297 has a flow path space on the outdoor unit 20A side in the refrigeration cycle A (flow path space shown by a broken line) and a flow path space on the outdoor unit 20B side in the refrigeration cycle B (shown by a solid line). Measure the differential pressure from the flow path space). The reference value calculation unit 298 calculates the reference value by the same method as in step S104 of FIG. 3 based on the atmospheric temperature at the position where the outdoor unit 20A is installed and the atmospheric temperature at the position where the outdoor unit 20B is installed. If the outdoor unit 20A and the outdoor unit 20B are installed in a space with the same atmospheric temperature, such as when the outdoor unit 20A and the outdoor unit 20B are installed in parallel, the reference value is not calculated and the preset fixed value is used. It may be used as a reference. Then, the evaluation unit 299 determines whether or not there is a differential pressure larger than the reference value. If there is no differential pressure, the evaluation unit 299 proceeds to step S205. On the other hand, if there is a differential pressure, the evaluation unit 299 advances the process to step S206.
In step S206, the evaluation unit 299 determines that no fluid such as nitrogen has leaked from both the flow path space on the outdoor unit 20A side in the refrigeration cycle A and the flow path space on the outdoor unit 20B side in the refrigeration cycle B. do. That is, the evaluation unit 299 determines that there is no fluid leakage from the refrigeration cycle A and the refrigeration cycle B, and the airtightness is ensured.

In step S207, the evaluation unit 299 determines which pressure is lower, the flow path space on the outdoor unit 20A side in the refrigeration cycle A or the flow path space on the outdoor unit 20B side in the refrigeration cycle B. When the pressure in the flow path space on the outdoor unit 20A side in the refrigeration cycle A is low, the evaluation unit 299 proceeds to the process in step S208. On the other hand, when the pressure in the flow path space on the outdoor unit 20B side in the refrigeration cycle B is low, the evaluation unit 299 proceeds to the process in step S209.
In step S208, the evaluation unit 299 determines that the fluid is leaking from the flow path space on the outdoor unit 20A side in the refrigeration cycle A. On the other hand, in step S209, it is determined that the fluid is leaking from the flow path space on the outdoor unit 20B side in the refrigeration cycle B.

*** Effect of Embodiment 2 ***
As described above, the airtightness evaluation device 100 according to the second embodiment evaluates the airtightness by the differential pressure in the flow path spaces of the two outdoor units 20A and 20B having the same capacity. The pressure of the fluid inside the vessel is affected by the volume of the vessel. Therefore, it is possible to improve the evaluation accuracy of the airtightness by evaluating the airtightness by the differential pressure in the flow path spaces of the two outdoor units 20A and 20B having the same volume.

In addition, the pressure of the fluid inside the container is affected by the ambient temperature.
In the first embodiment, the airtightness was evaluated by the differential pressure between the flow path space of the outdoor unit 20 and the other flow path spaces including the flow path spaces of the indoor units 30 and 40. The outdoor unit 20 and the indoor units 30 and 40 are often installed in spaces having different temperatures such as outdoors and indoors. On the other hand, the two outdoor units 20A and 20B are often installed in a space having substantially the same temperature. As a specific example, in large buildings and condominiums and commercial facilities, outdoor units of the same type are often installed in parallel on the rooftop. In this case, it can be said that each outdoor unit is installed in a space having substantially the same temperature. Therefore, it is possible to improve the evaluation accuracy of the airtightness by evaluating the airtightness by the differential pressure in the flow path spaces of the two outdoor units 20A and 20B having the same volume.

*** Other configurations ***
<Modification 6>
In the second embodiment, the air conditioning system 11 is composed of two outdoor units 20A and 20B and four indoor units 30A, 40A, 30B and 40B. However, the air conditioning system 11 may be composed of three or more outdoor units 20 and five or more indoor units 30, 40.

The embodiments and modifications of the present invention have been described above. Some of these embodiments and modifications may be combined and carried out. In addition, any one or several may be partially carried out. The present invention is not limited to the above embodiments and modifications, and various modifications can be made as necessary.

10 Refrigeration cycle system, 11 Air conditioning system, 20 Outdoor unit, 21 Compressor, 22 Four-way valve, 23 Outdoor heat exchanger, 24 Outdoor blower, 25, 26 Valve connection port, 27, 28 connection port, 29 unit controller, 211,212,213,214,215 Temperature sensor, 291 measurement unit, 292 calculation unit, 293 control unit, 294 unit communication unit, 295 unit storage unit, 296 division unit, 297 differential pressure measurement unit, 298 reference value calculation unit, 299 Evaluation unit, 30,40 indoor unit, 31,41 decompression mechanism, 32,42 indoor heat exchanger, 33,43 indoor blower, 34,44 connection port with valve, 35,45 valve, 311,312,313,411 , 421,413 Temperature sensor, 51,52,53 Liquid pipe, 61,62,63 Gas pipe, 70 External control device, 71 Input unit, 72 External communication unit, 73 Storage unit, 74 Display unit, 80 Differential pressure gauge, 81 , 82 Connection port, 100 Airtightness evaluation device.

Claims (6)

For each of the two steam compression type refrigeration cycles, a partition portion that divides the flow path constituting the target refrigeration cycle by a valve to form a plurality of flow path spaces, and
Two flows, one is a flow path space formed by dividing one of the two refrigeration cycles by the divided portion, and the other is a flow path space formed by dividing the other refrigerating cycle by the divided portion. A differential pressure measuring unit that measures the differential pressure in the road space,
An airtightness evaluation device including an evaluation unit for evaluating the airtightness of the two flow path spaces based on the differential pressure measured by the differential pressure measuring unit. The airtightness according to claim 1, wherein the evaluation unit determines that there is a fluid leakage in the flow path space having the lower pressure among the two flow path spaces when the differential pressure is equal to or higher than the reference value. Evaluation device. The division unit further divides the flow path space determined by the evaluation unit to have fluid leakage to form a plurality of flow path spaces.
The differential pressure measuring unit measures the differential pressure of two flow path spaces out of the plurality of flow path spaces formed by dividing the flow path space determined to have fluid leakage.
The airtightness evaluation according to claim 2, wherein the evaluation unit evaluates the airtightness of the two flow path spaces formed by dividing the flow path space determined to have fluid leakage due to the differential pressure. Device. The division portion divides the refrigerating cycle of the target into an outdoor unit space, which is a flow path space for connecting devices housed in the outdoor unit, and another flow path space.
The claim that the differential pressure measuring unit measures the differential pressure between the outdoor unit space formed by dividing one refrigerating cycle and the outdoor unit space formed by dividing the other refrigerating cycle. The airtightness evaluation device according to any one of 1 to 3 . The airtightness evaluation device further
A reference value calculation unit for calculating a reference value based on the ambient temperature of the two flow path spaces is provided.
The item according to any one of claims 1 to 4 , wherein the evaluation unit evaluates the airtightness of the two flow path spaces based on the reference value calculated by the reference value calculation unit and the differential pressure. Airtightness evaluation device. For each of the two steam compression type refrigeration cycles, the fluid is sealed in the flow path that constitutes the target refrigeration cycle.
For each of the two refrigeration cycles, the flow paths constituting the target refrigeration cycle are divided by a valve to form a plurality of flow path spaces.
A differential pressure gauge is connected to two flow path spaces, one is a flow path space formed by dividing one of the two refrigeration cycles and the other is a flow path space formed by dividing the other refrigeration cycle. A method for determining airtightness for determining whether or not the airtightness of the two flow path spaces is ensured by measuring the differential pressure between the two flow path spaces.

Images