WO2017068686A1

WO2017068686A1 - Refrigeration cycle device

Info

Publication number: WO2017068686A1
Application number: PCT/JP2015/079850
Authority: WO
Inventors: 伸哲上原
Original assignee: 三菱電機株式会社
Priority date: 2015-10-22
Filing date: 2015-10-22
Publication date: 2017-04-27
Also published as: CN206420200U; JPWO2017068686A1; JP6381824B2

Abstract

This refrigeration cycle device is equipped with: a refrigerant circuit, which is provided with a compressor, a condenser, a depressurizing device, and an evaporator, and in which a flammable refrigerant is circulated; a leakage speed estimation unit that estimates the speed of refrigerant leakage from the refrigerant circuit; a refrigerant leakage detection sensor that detects the refrigerant leakage from the refrigerant circuit; a deterioration detection unit that determines that the detection sensitivity of the refrigerant leakage detection sensor is deteriorated in the cases where the refrigerant leakage speed estimated by the leakage speed estimation unit is equal to or higher than a reference value, and the refrigerant leakage has not been detected even once by the refrigerant leakage detection sensor; and a notification unit that notifies the deterioration of the refrigerant leakage detection sensor in the cases where the deterioration has been detected by the deterioration detection unit.

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus used in refrigeration equipment, a low temperature apparatus, an air conditioner, and the like, and particularly relates to a protective function for ensuring safety in a refrigeration cycle apparatus using a flammable refrigerant. .

For example, in an air conditioner as a refrigeration cycle apparatus using a combustible refrigerant, in order to prevent refrigerant ignition in the living space at the time of refrigerant leakage, the presence or absence of refrigerant leakage is determined based on operating state information such as refrigerant pressure and temperature. There is a technology including a refrigerant leakage detection sensor for detection (see, for example, Patent Document 1).

JP 2007-263539 A

Depending on the type of refrigerant leak detection sensor, the detection sensitivity may decrease due to aging. If the operation of the air conditioner is continued with the detection sensitivity of the refrigerant leakage detection sensor being lowered, there is a problem that the detection is delayed despite the refrigerant leakage, and safety cannot be ensured.

In addition, it has been found that the ignition due to the leakage of the combustible refrigerant is largely related to the refrigerant leakage speed. In a gradual leak with a low leak rate, diffusion into the indoor space proceeds and the gas concentration is reduced, so that the refrigerant concentration in the room does not fall within the ignition concentration range. However, when a large amount of refrigerant leaks into the room within a short time, a high refrigerant concentration region occurs. For this reason, a safety measure in consideration of the refrigerant leakage rate is required.

The present invention has been made in view of the above points, and can detect and notify a decrease in the detection sensitivity of the refrigerant leakage detection sensor, thereby reducing the occurrence of a high refrigerant concentration region due to a decrease in the sensitivity of the refrigerant leakage detection sensor. An object is to obtain a refrigeration cycle apparatus.

A refrigeration cycle apparatus according to the present invention includes a compressor, a condenser, a decompression device, and an evaporator, a refrigerant circuit in which a flammable refrigerant circulates, a leak rate estimation unit that estimates a rate of refrigerant leak from the refrigerant circuit, A refrigerant leak detection sensor for detecting refrigerant leak from the refrigerant circuit and a refrigerant leak rate estimated by the leak rate estimation unit equal to or higher than a reference value and no refrigerant leak has been detected by the refrigerant leak detection sensor. A deterioration detection unit that determines that the detection sensitivity of the leakage detection sensor has decreased, and a notification unit that notifies that when the deterioration of the detection sensitivity of the refrigerant leakage detection sensor is detected by the deterioration detection unit. .

According to the present invention, since a decrease in detection sensitivity of the refrigerant leak detection sensor is detected and notified, replacement and repair of the refrigerant leak detection sensor can be promoted. As a result, it is possible to reduce the occurrence of a high refrigerant concentration region due to a decrease in sensitivity of the refrigerant leakage detection sensor and the disadvantage of refrigerant ignition.

It is a figure which shows the refrigerant circuit of the air conditioning apparatus in Embodiment 1 of this invention. It is a control block diagram of the control apparatus of the air conditioning apparatus of FIG. It is a flowchart which shows the flow of the refrigerant | coolant leakage detection sensor deterioration detection process of the air conditioning apparatus in Embodiment 1 of this invention.

Hereinafter, the structure of the air conditioning apparatus which is an example of a refrigeration cycle apparatus will be described.
Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a refrigerant circuit of the air-conditioning apparatus according to Embodiment 1 of the present invention.
The air conditioner in Embodiment 1 includes a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, a decompression device 14 including an expansion valve, a refrigerant container 15, and an indoor heat exchanger 21, and is combustible. A refrigerant circuit in which the refrigerant circulates is provided. The air conditioner further includes an outdoor fan 16 that blows air to the outdoor heat exchanger 13 and an indoor fan 22 that blows air to the indoor heat exchanger 21.

The compressor 11, the four-way valve 12, the outdoor heat exchanger 13, the decompression device 14, and the refrigerant container 15 are arranged in the outdoor unit 1, and the indoor heat exchanger 21 and the indoor blower 22 are arranged in the indoor unit 2. Further, the outdoor unit 1 is further provided with a discharge temperature sensor 17 for detecting the temperature discharged from the compressor 11. The indoor unit 2 is further provided with a refrigerant leakage detection sensor 23 that detects refrigerant leakage from the refrigerant circuit. In addition to the discharge temperature sensor 17 and the refrigerant leakage detection sensor 23, the air conditioner is provided with a plurality of sensors for detecting temperatures and pressures at various locations in the refrigerant circuit, and detection from various sensors in the air conditioner. A signal is input to a control device 31 described later.

The specific configuration of the refrigerant leakage detection sensor 23 is not particularly limited, and an existing technology can be adopted. As the refrigerant leakage detection sensor 23, for example, the technique described in Patent Document 1 may be employed. That is, a sensor for detecting the pressure and temperature of the refrigerant in the refrigerant circuit is provided, and the current refrigerant amount in the refrigerant circuit is calculated based on the measured value measured from each sensor during the refrigerant leak detection operation. It is good also as a structure which detects a refrigerant | coolant leakage from the difference with a refrigerant | coolant amount. In addition to the refrigerant leakage detection sensor 23, for example, a technique described in JP-A-2002-5548 may be employed. That is, it is good also as a structure provided with the electric current detection sensor which detects a compressor driving current, and judging that the refrigerant | coolant leaks when the electric current detected with the electric current detection sensor became below the reference value. In addition, for example, a gas concentration sensor may be used as the refrigerant leakage detection sensor 23.

When refrigerant leakage is detected by the refrigerant leakage detection sensor 23, the detection signal is input to the control device 31 described later, and a display indicating that refrigerant leakage has occurred is displayed on the display unit 35 described later. Yes.

The air conditioner configured as described above can perform a cooling operation or a heating operation by switching the four-way valve 12. When the four-way valve 12 is switched to the solid line side in FIG. 1, the indoor heat exchanger 21 is an evaporator and the outdoor heat exchanger 13 is a condenser to perform a cooling operation, and the four-way valve 12 is switched to the dotted line side in FIG. In this case, the indoor heat exchanger 21 is a condenser and the outdoor heat exchanger 13 is an evaporator, and the heating operation is performed.

The air conditioner includes an outdoor unit control device 31a that controls the entire outdoor unit and an indoor unit control device 31b that controls the entire indoor unit. The indoor unit control device 31b exchanges control signals and the like with the remote controller 34 for individually operating the indoor unit 2, and communicates with the outdoor unit control device 31a via a transmission line (may be wireless). It is possible to exchange control signals and the like. Below, when uniting the indoor unit control apparatus 31b and the outdoor unit control apparatus 31a, it demonstrates as the control apparatus 31. FIG. The control device 31 can be configured by hardware such as a circuit device that realizes the function, or can be configured by an arithmetic device such as a microcomputer or a CPU, and a control program executed thereon. .

The remote controller 34 includes a display unit 35 configured with a liquid crystal panel or the like. The display unit 35 displays an operation mode, a message indicating that a refrigerant leak has occurred, a message indicating that the detection sensitivity of the refrigerant leak detection sensor 23 has decreased, and the like. The display unit 35 corresponds to a notification unit of the present invention that notifies a decrease in detection sensitivity of the refrigerant leakage detection sensor 23. As the notification unit, for example, a speaker or the like may be used.

(Control block configuration of refrigeration air conditioner)
FIG. 2 is a control block diagram of the control device of the air conditioner of FIG.
The control device 31 performs drive frequency control of the compressor 11 and opening degree control of the decompression device 14 based on detection signals from various sensors in the air conditioning apparatus. In addition, the control device 31 includes a leakage rate estimation unit 32 that estimates the rate of refrigerant leakage from the refrigerant circuit, and a deterioration detection unit 33 that detects a decrease in detection sensitivity of the refrigerant leakage detection sensor 23. The leak rate estimation unit 32 and the deterioration detection unit 33 are functionally configured by a CPU and a control program.

The leakage rate estimation unit 32 estimates the refrigerant leakage rate based on detection signals from various sensors in the air conditioner. The method for estimating the refrigerant leak rate in the leak rate estimating unit 32 is not particularly limited, and an existing technique can be adopted. For example, using the technique disclosed in Japanese Patent No. 4799563, first, an operation of detecting the refrigerant charge amount filled in the refrigerant circuit from the information of the pressure and temperature of the refrigerant is performed a plurality of times, and the refrigerant charge amount for each time Is calculated. Then, the refrigerant leakage rate can be estimated by dividing the difference between the respective refrigerant charging amounts by the detection operation interval time. In addition, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2002-5548 may be adopted in which the rate of decrease in compressor operating current during compressor operation is estimated as the refrigerant leakage rate. The leak rate estimation unit 32 estimates the leak rate independently of the detection result of the refrigerant leak detection sensor 23.

The deterioration detection unit 33 detects a decrease in detection sensitivity of the refrigerant leak detection sensor 23 based on the detection result of the refrigerant leak detection sensor 23 and the estimation result of the leak rate estimation unit 32. Specifically, the deterioration detection unit 33 has a refrigerant leakage rate detected by the leakage rate estimation unit 32 that is equal to or higher than a reference value for determining a decrease in detection sensitivity, and the refrigerant leakage detection sensor 23 performs refrigerant leakage. Is not detected at all, it is determined that the detection sensitivity of the refrigerant leakage detection sensor 23 is lowered. In a situation where the detection sensitivity of the refrigerant leak detection sensor 23 is lowered, the actual refrigerant concentration when the refrigerant leak detection sensor 23 detects that there is a refrigerant leak is higher than the refrigerant concentration that should be detected as having a refrigerant leak. Will be higher.

Next, the operation of the refrigeration cycle of the air conditioner will be described with reference to FIG.

(Heating operation)
In the heating operation, the four-way valve 12 is switched to the state indicated by the dotted line in FIG. In the air conditioner, during the heating operation, the refrigerant compressed by the compressor 11 becomes a high-temperature and high-pressure gas refrigerant and is sent to the indoor heat exchanger 21 through the four-way valve 12. The refrigerant flowing into the indoor heat exchanger 21 is liquefied by exchanging heat with the indoor air conveyed by the indoor blower 22 and dissipating heat. The liquefied refrigerant passes through the refrigerant container 15 and is decompressed by the decompression device 14 to be in a gas-liquid two-phase state. The refrigerant in the gas-liquid two-phase state flows into the outdoor heat exchanger 13, exchanges heat with outdoor air conveyed by the outdoor blower 16, gasifies by absorbing heat, and returns to the compressor 11. As described above, the heating operation is performed by circulating the refrigerant through the refrigerant circuit.

(Cooling operation)
In the cooling operation, the four-way valve 12 is switched to the state shown by the solid line in FIG. In the air conditioner, during the cooling operation, the refrigerant compressed by the compressor 11 becomes a high-temperature and high-pressure gas refrigerant, which is sent to the outdoor heat exchanger 13 through the four-way valve 12. The refrigerant flowing into the outdoor heat exchanger 13 is liquefied by exchanging heat with the outdoor air conveyed by the outdoor blower 16 and dissipating heat. The liquefied refrigerant is decompressed by the decompression device 14 to become a gas-liquid two-phase state, and flows into the indoor heat exchanger 21 through the refrigerant container 15. The refrigerant that has flowed into the indoor heat exchanger 21 exchanges heat with the indoor air conveyed by the indoor blower 22, gasifies by absorbing heat, and is returned to the compressor 11. As described above, the refrigerant circulates through the refrigerant circuit to perform the cooling operation.

FIG. 3 is a flowchart showing the flow of the refrigerant leak detection sensor deterioration detection process of the air-conditioning apparatus according to Embodiment 1 of the present invention. The flowchart of FIG. 3 is performed at every deterioration detection timing of the refrigerant leakage detection sensor. Although not shown in FIG. 3, it is assumed that the air conditioner checks whether there is a refrigerant leak at the refrigerant leak detection sensor 23 at all times or at an appropriate timing.

In the air conditioner, when the deterioration detection timing of the refrigerant leakage detection sensor 23 comes, the leakage speed estimation unit 32 estimates the refrigerant leakage speed (S1). The estimation of the refrigerant leakage rate in the leakage rate estimation unit 32 may be performed using a conventionally known technique as described above. Then, the deterioration detection unit 33 checks whether or not the refrigerant leakage rate estimated by the leakage rate estimation unit 32 is equal to or higher than a reference value and the refrigerant leakage detection sensor 23 has never detected the refrigerant leakage (S2). . When the refrigerant leakage rate is equal to or higher than the reference value and the refrigerant leakage detection sensor 23 has never detected the refrigerant leakage, the deterioration detection unit 33 has a reduced detection sensitivity of the refrigerant leakage detection sensor 23. to decide.

In response to this determination in the deterioration detection unit 33, the control device 31 performs predetermined control when the refrigerant leaks (S3). In other words, the control device 31 displays and notifies the display unit 35 of the remote controller 34 that “sensor sensitivity is reduced”. This notification is not limited to the display unit 35 of the remote controller 34 as described above, and may be notified by voice, or the display unit (not shown) of the indoor unit 2 and the display unit (not shown) of the outdoor unit 1. You may make it display and alert | report. By this notification, it is possible to notify the user or service person that the sensitivity of the refrigerant leak detection sensor 23 is reduced, and it is possible to prompt the user to replace or repair the refrigerant leak detection sensor 23.

In addition, the control device 31 operates the indoor blower 22 for a certain period of time as a predetermined control when the refrigerant leaks, and stirs the ambient air to prevent the indoor refrigerant concentration from entering the ignition concentration range. In addition, although the sensitivity fall of the refrigerant | coolant leak detection sensor 23 was detected here and not the refrigerant | coolant leak itself was detected, possibility that the refrigerant | coolant leak was overlooked by the sensitivity fall of the refrigerant | coolant leak detection sensor 23 is denied. Since this is not possible, control similar to that normally performed when refrigerant leakage is detected is performed.

On the other hand, if the sensitivity decrease of the refrigerant leak detection sensor 23 is not detected in step S2, the refrigerant leak detection sensor deterioration detection process is terminated.

As described above, according to the first embodiment, a decrease in detection sensitivity of the refrigerant leakage detection sensor 23 is detected and notified. For this reason, it is possible to notify the user or serviceman of a decrease in detection sensitivity of the refrigerant leak detection sensor 23 and to prompt replacement or repair of the refrigerant leak detection sensor 23. As a result, it is possible to reduce the possibility of occurrence of a high refrigerant concentration region and refrigerant ignition due to a decrease in detection sensitivity of the refrigerant leakage detection sensor 23.

Further, as an algorithm for detecting the deterioration of the refrigerant leakage detection sensor 23, the refrigerant leakage speed detected by the leakage speed estimation unit 32 is equal to or higher than a reference value for determining a decrease in detection sensitivity, and the refrigerant leakage detection is performed. When the sensor 23 has never detected the refrigerant leakage, it is determined that the detection sensitivity of the refrigerant leakage detection sensor 23 is lowered. For this reason, generation | occurrence | production of the high refrigerant | coolant concentration area | region by the detection sensitivity fall of the refrigerant | coolant leakage detection sensor 23, and the possibility of refrigerant | coolant ignition can be reduced. Conventionally, the technique of the first embodiment is very effective because there is no viewpoint of detecting and notifying the detection sensitivity decrease of the refrigerant leakage detection sensor 23 in the past.

In the first embodiment, the deterioration detection timing is always performed or at an appropriate timing, but may be performed in cooperation with refrigerant leakage detection. That is, when the refrigerant leakage detection is performed, for example, at the timing of manual operation or schedule setting, the deterioration detection may be performed following the refrigerant leakage detection timing.

Further, in the first embodiment, the configuration in which the refrigerant leakage detection sensor 23 is provided on the indoor unit side is illustrated. However, the refrigerant leakage detection sensor 23 is provided on the outdoor unit side to detect refrigerant leakage and estimate the refrigerant leakage speed. It may be.

In the first embodiment, the refrigeration cycle apparatus is described as an air conditioner. However, the refrigeration cycle apparatus may be a cooling apparatus that cools a refrigerated warehouse or the like.

1 outdoor unit, 2 indoor unit, 11 compressor, 12 four-way valve, 13 outdoor heat exchanger, 14 decompression device, 15 refrigerant container, 16 outdoor blower, 17 discharge temperature sensor, 21 indoor heat exchanger, 22 indoor blower, 23 Refrigerant leak detection sensor, 31 control device, 31a outdoor unit control device, 31b indoor unit control device, 32 leak rate estimation unit, 33 deterioration detection unit, 34 remote control, 35 display unit.

Claims

A refrigerant circuit including a compressor, a condenser, a pressure reducing device, and an evaporator, in which a combustible refrigerant circulates;
A leakage rate estimation unit for estimating a rate of refrigerant leakage from the refrigerant circuit;
A refrigerant leakage detection sensor for detecting refrigerant leakage from the refrigerant circuit;
If the refrigerant leak rate estimated by the leak rate estimation unit is equal to or higher than a reference value and no refrigerant leak has been detected by the refrigerant leak detection sensor, it is determined that the detection sensitivity of the refrigerant leak detection sensor has decreased. A degradation detector;
A refrigeration cycle apparatus comprising: an informing unit for informing that a deterioration in detection sensitivity of the refrigerant leakage detection sensor is detected by the deterioration detection unit.
An indoor unit having an indoor heat exchanger that functions as the condenser or the evaporator;
The refrigeration cycle apparatus according to claim 1, wherein the refrigerant leakage detection sensor is arranged in the indoor unit.