Leakage detection method for combustible refrigerant indoor unit and air conditioner multi-connected unit

Abstract

The invention discloses a leakage detection method for a combustible refrigerant indoor unit and an air conditioner multi-connected unit using the method. The method comprises the following steps: presetting an initial dormancy period of an indoor unit refrigerant sensor according to design and debugging parameters; the initial dormancy period is corrected according to the accumulated working time and the fault frequency of the indoor unit; and the dormancy period of the indoor unit refrigerant sensor is dynamically adjusted according to the running state of the indoor unit, so that the indoor unit refrigerant sensor is subjected to intermittent leakage detection. For a large multi-split air conditioning system, the working time of the refrigerant sensor is shortened, energy conservation is facilitated, and economic benefits are improved.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and in particular to a leakage detection method for a flammable refrigerant indoor unit and an air-conditioning multi-unit unit using the method. Background Art

[0002] With increasing environmental protection requirements, the environmental advantages of combustible refrigerants are gaining widespread recognition, primarily due to their low global warming potential (GWP), zero ozone depletion potential (ODP), and the natural origin of some refrigerants. Furthermore, combustible refrigerants offer the following advantages: excellent thermodynamic properties, improved energy efficiency, reduced electricity consumption, and thus indirectly lowering carbon emissions associated with power generation (especially in regions with a high proportion of coal-fired power generation); and minimal environmental impact throughout their lifecycle. The extraction and purification process for combustible refrigerants emits far less carbon than the synthesis of fluorinated refrigerants, requiring no special decomposition process and evaporating naturally.

[0003] Environmentally friendly refrigerants are gaining increasing attention in the refrigeration industry. The use of flammable refrigerants in air conditioning, heat pumps, and other fields is gradually increasing. Flammable refrigerants such as R32 and R290 have also entered the air conditioning industry. However, flammable refrigerants are refrigerants that can ignite under certain conditions. These refrigerants typically have low flash points or flammability limits, and can ignite or explode when exposed to open flames, high temperatures, or sparks. Therefore, their safety requires strict control.

[0004] Combustible refrigerants meet global environmental requirements, but their flammability also presents safety risks. Monitoring refrigerant leaks in refrigeration systems using flammable refrigerants has become a crucial issue. A common approach is to use refrigerant sensors to detect leaks, particularly in indoor environments. This prevents excessive refrigerant levels in applications, reaching the lower flammable limit and potentially causing combustion or explosions, resulting in property damage or casualties.

[0005] Existing refrigerant sensors are monitored in real time, which is relatively safe for a single system. However, for large-scale multi-split air conditioning system projects, there are a large number of indoor units. The diverse usage time of these indoor units requires all refrigerant sensors to be monitored in real time. However, the real-time power supply of a large number of refrigerant sensors will lead to energy waste. Summary of the Invention

[0006] The present invention proposes a leak detection method for a flammable refrigerant indoor unit and an air-conditioning multi-split unit using the method, so as to solve the energy waste problem caused by the real-time power supply of a large number of refrigerant sensors, extend the service life of the sensors, and reduce maintenance costs.

[0007] The technical solution adopted by the present invention is to propose a leakage detection method for a combustible refrigerant indoor unit, comprising:

[0008] Preset the initial sleep cycle of the refrigerant sensor in the indoor unit according to the design and debugging parameters;

[0009] Modify the initial sleep cycle according to the cumulative working time and failure frequency of the indoor unit;

[0010] Calculate the sleep cycle of the refrigerant sensor in the indoor unit according to the operating state of the indoor unit, so that the refrigerant sensor in the indoor unit performs intermittent leak detection.

[0011] Further, the modification includes: time correction parameter A, failure correction parameter B, and high-pressure correction parameter C.

[0012] In an embodiment, the method for detecting the leakage of the combustible refrigerant in the indoor unit proposed by the present invention includes the following steps:

[0013] Preset the initial sleep cycle W of the indoor unit;

[0014] Select the time correction parameter A and the failure correction parameter B of the indoor unit;

[0015] Judge whether the indoor unit is in the on state. If so, determine the high-pressure correction parameter C according to the high-pressure area of the unit, and then calculate the sleep cycle of the refrigerant sensor in the indoor unit in the on state; if not, calculate the sleep cycle of the refrigerant sensor in the indoor unit in the off state.

[0016] Further, when the indoor unit is in the on state, the sleep cycle Q of the refrigerant sensor in the indoor unit is calculated according to the following formula: Q = A * B * C * W.

[0017] Further, when the indoor unit is in the off state, the sleep cycle Q of the refrigerant sensor in the indoor unit is calculated according to the following formula: Q = A * B * N * W, where N is a value greater than 1.

[0018] Preferably, the time correction parameter A of the indoor unit takes values according to the following table:

[0019] .

[0020] Preferably, the failure correction parameter B of the indoor unit takes values according to the following table:

[0021] .

[0022] Preferably, the high-pressure correction parameter C takes values according to the following table:

[0023] .

[0024] Preferably, if the calculated sleep cycle Q is less than the minimum value T, it is controlled according to the minimum value.

[0025] Preferably, the detection time of the refrigerant sensor in the indoor unit each time is t.

[0026] Furthermore, the indoor unit refrigerant leakage detection method proposed by the present invention further includes an indoor unit sleep execution step:

[0027] Determine whether the calculated indoor unit sleep cycle is less than the minimum value T. If so, execute the sleep cycle according to the minimum value; if not, run according to the actually calculated sleep cycle.

[0028] When the indoor unit refrigerant sensor alarms, enter real-time monitoring and switch to manual recovery.

[0029] The present invention also proposes a multi-split air conditioner unit, including an outdoor unit and an indoor unit, and the indoor unit adopts the above-mentioned combustible refrigerant indoor unit leakage detection method.

[0030] Compared with the prior art, the technical solution proposed by the present invention has the following beneficial effects:

[0031] 1. The present invention fully considers the cumulative operation time and the number of failures of the large multi-split air conditioner system, dynamically adjusts the sleep cycle of the indoor unit on the basis of ensuring safety and reliability, performs intermittent detection on the indoor unit, reduces the working time of the refrigerant sensor, and extends the service life of the refrigerant sensor.

[0032] 2. For large multi-split air conditioner systems, there are numerous refrigerant sensors. Reducing the working time of the refrigerant sensors is beneficial for energy conservation and improves economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, where:

[0034] Figure 1 is a system schematic diagram of a multi-split air conditioner unit;

[0035] Figure 2 is a principle block diagram for determining the sleep cycle of the indoor unit refrigerant sensor of the present invention;

[0036] Figure 3 is a control flowchart of the sleep cycle of the indoor unit refrigerant sensor;

[0037] Figure 4 is a flowchart for executing the sleep state of the indoor unit.

[0038] Wherein:

[0039] 1 compressor, 2 four-way valve, 3 outdoor heat exchanger, 4 expansion valve, 5 indoor unit, 6 stop valve, 7 refrigerant sensor, 8 temperature sensor, 9 pressure sensor.

[0040] W preset initial sleep cycle;

[0041] A time correction parameter;

[0042] B failure correction parameter;

[0043] C High-pressure correction parameter;

[0044] Q Hibernation cycle;

[0045] t Leak detection time;

[0046] T Minimum value of the hibernation cycle. Detailed implementation manners

[0047] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation to the present invention.

[0048] The terms used in this specification are only for describing specific implementation manners and are not intended to limit the present invention. Unless otherwise specifically stated, the relative arrangements, numerical expressions and values of the components and steps described in these embodiments do not limit the protection scope of the present invention.

[0049] For the technologies, methods and devices known to those of ordinary skill in the relevant fields, no detailed discussion is made in this specification, but where appropriate, the said technologies, methods and devices should be regarded as a part of this specification. Any specific value in this specification should be construed as merely exemplary and not as a limitation to the present invention.

[0050] For the convenience of description, the terms for describing positions used in the specification, such as "above...", "to the left of...", "in front of...", etc., are only used to describe the spatial position relationship between a certain component and other components in the embodiments shown in the drawings. When the position where the component is placed is different, the relative position will change. Therefore, the positional relationship in the embodiments of the drawings should not constitute a limitation to the present invention. In addition, it should be noted that the terms "first", "second", etc. used in the specification are only used to distinguish similar components and there is no sequence, so it cannot be construed as a limitation to the protection scope of the present invention.

[0051] The concept of the present invention is: by intermittently detecting the refrigerant leakage in the indoor unit, the working time of the refrigerant sensor is reduced, the service life of the refrigerant sensor is extended on the basis of ensuring safety and reliability, and the energy consumption is reduced.

[0052] Figure 1 It is a system schematic diagram of an air-conditioning multi-connected unit. The multi-connected unit includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an electronic expansion valve 4 and multiple parallel indoor units 5 connected by pipelines. A stop valve 6 is provided on each parallel branch. A temperature sensor 8 and a pressure sensor 9 are provided on the compressor discharge pipeline.

[0053] When the multi - split air conditioner unit is in the cooling mode, the refrigerant is compressed by the compressor 1 and discharged as a high - temperature and high - pressure refrigerant gas. This gas is introduced into the outdoor heat exchanger 3 through the four - way valve 2 and condensed into a high - pressure and normal - temperature refrigerant liquid. Then it passes through the electronic expansion valve 4 for throttling and becomes a low - temperature and low - pressure refrigerant liquid. This liquid is introduced into the indoor unit 5, exchanges heat with the indoor air and evaporates into a low - temperature and low - pressure refrigerant gas. Then it returns to the compressor 1 through the four - way valve 2 for recycling.

[0054] When the multi - split air conditioner unit is in the heating mode, the refrigerant is compressed by the compressor 1 and discharged as a high - temperature and high - pressure refrigerant gas. This gas is introduced into the indoor unit 5 through the four - way valve 2, exchanges heat with the indoor air and is condensed into a high - pressure and normal - temperature refrigerant liquid. Then it passes through the electronic expansion valve 4 for throttling and becomes a low - temperature and low - pressure refrigerant liquid. This liquid is introduced into the outdoor heat exchanger 3, exchanges heat and evaporates into a low - temperature and low - pressure refrigerant gas. Then it returns to the compressor 1 through the four - way valve 2 for recycling.

[0055] As mentioned above, the combustible refrigerant has been widely used for its environmental protection advantages, but its combustible nature poses potential safety hazards. To solve this problem, a common method is to use a refrigerant sensor to detect refrigerant leakage, especially to monitor the indoor environment to prevent the refrigerant content in the application site from being too high and reaching the lower flammable limit, which may cause combustion or explosion, resulting in property damage or casualties. As Figure 1 shown, a refrigerant sensor 7 is installed on each indoor unit 5. When the refrigerant sensor detects that the refrigerant leakage in the indoor unit reaches a certain concentration, it will alarm to avoid dangerous accidents. However, for large - scale multi - split air conditioner systems, there are a large number of indoor units. The diversity of the usage time of these indoor units requires that all refrigerant sensors must be in a real - time monitoring state, and the real - time power supply of a large number of refrigerant sensors will lead to the problem of energy waste.

[0056] Through a large amount of experimental data, it is found that the longer the cumulative operating time of the air conditioner unit, the greater the probability of refrigerant leakage; the higher the number of faults of the air conditioner unit, the greater the probability of refrigerant leakage; the higher the high - pressure of the air conditioner unit, the greater the probability of refrigerant leakage. In addition, when the indoor unit is in the shutdown state, the probability of possible leakage is smaller. Based on these characteristics, the idea of the present invention is: to preset an initial sleep cycle for the refrigerant sensor of the indoor unit to work intermittently according to the design parameters and debugging status of the multi - split air conditioner unit, so that the refrigerant sensor of the indoor unit is powered off and enters the sleep cycle after working for a period of time, and enters the working period again after the sleep cycle ends, thereby achieving the purpose of reducing energy consumption.

[0057] The above - mentioned sleep cycle specifically includes the following three aspects:

[0058] First, preset the initial sleep cycle of the refrigerant sensor on the premise of ensuring the safety and reliability of the system;

[0059] Second, modify the preset initial sleep cycle according to the cumulative operation time and failure times of the air conditioner unit;

[0060] Third, dynamically adjust the preset initial sleep cycle according to whether the indoor unit is working.

[0061] By setting the sleep (power-off) cycle of the refrigerant sensor in the indoor unit, the present invention intermittently detects refrigerant leakage in the indoor unit to reduce the working time of the refrigerant sensor, extend the service life of the refrigerant sensor on the basis of ensuring safety and reliability, and reduce energy consumption.

[0062] As Figure 2 shown, the leakage detection method for the combustible refrigerant indoor unit proposed by the present invention includes:

[0063] Preset the initial sleep cycle of the refrigerant sensor in the indoor unit according to the design and debugging parameters;

[0064] Modify the initial sleep cycle according to the cumulative working time and failure frequency of the indoor unit;

[0065] Calculate the sleep cycle of the refrigerant sensor in the indoor unit according to the operating state of the indoor unit, so that the refrigerant sensor in the indoor unit performs intermittent detection.

[0066] The above modifications include: time correction parameter A, failure correction parameter B, and high-pressure correction parameter C.

[0067] After the preset initial sleep cycle is set, the system automatically detects the number of refrigerant sensors in the indoor units of the multi-connected unit, and then obtains the cumulative working time and failure times of each indoor unit through engineering memory. Among them, the time correction parameter A reflecting the cumulative working time of the indoor unit (calculated from the normal operation time after debugging) and the failure correction parameter (cumulative failure times) B are selected with reference to the following table:

[0068] Value of time correction parameter A

[0069] .

[0070] Value of failure correction parameter B

[0071] .

[0072] Whether the indoor unit is a working indoor unit can be distinguished through the indoor unit parameters, and the sleep cycle of the shutdown indoor unit can be longer. If the sleep cycle of the powered-on indoor unit is Q, the sleep cycle of the unpowered-on indoor unit can be N times that of the powered-on indoor unit, and the value range of N is a value greater than 1, and the value range is [1, 10]. For example, if the sleep cycle of the powered-on indoor unit is 5 minutes, the sleep cycle of the shutdown indoor unit is 2 times that of the powered-on indoor unit, which is 10 minutes.

[0073] As an embodiment, the state of the indoor unit at startup is corrected based on the high pressure of the unit system. The value range of the high-pressure correction parameter C is as follows:

[0074] Value of the high-pressure correction parameter C

[0075] .

[0076] The above preset initial sleep cycle and correction parameter data are derived from a large amount of experimental statistical data. For different units and different application environments, the above data may change.

[0077] Figure 3 is the control flow chart of the sleep cycle of the indoor unit refrigerant sensor. The combustible refrigerant indoor unit leakage detection method proposed by the present invention includes the following steps:

[0078] Preset the initial sleep cycle W of the indoor unit;

[0079] Select the time correction parameter A and the fault correction parameter B of the indoor unit;

[0080] Judge whether the indoor unit is in the startup state. If so, determine the high-pressure correction parameter C according to the high-pressure area of the unit, and then calculate the sleep cycle Q of the refrigerant sensor of the indoor unit in the startup state; if not, calculate the sleep cycle Q of the refrigerant sensor of the indoor unit in the shutdown state.

[0081] When the indoor unit is in the startup state, the sleep cycle Q of the refrigerant sensor of the indoor unit is calculated according to the following formula: Q = A * B * C * W.

[0082] When the indoor unit is in the shutdown state, the sleep cycle Q of the refrigerant sensor of the indoor unit is calculated according to the following formula: Q = A * B * N * W, where N should be a value greater than 1. The value of N is based on the fact that the probability of leakage when the indoor unit is shutdown is smaller, so the sleep cycle of the indoor unit can be increased when it is shutdown.

[0083] The present invention calculates the sleep cycle Q of each refrigerant sensor by presetting the initial sleep cycle and parameter correction; by intelligently adjusting the working frequency of the refrigerant sensor of the indoor unit, its service life is extended, energy consumption is reduced, and safety is ensured at the same time.

[0084] The following is an example to illustrate the calculation of the sleep cycle:

[0085] First, preset the initial sleep cycle W of the refrigerant sensor of the indoor unit to 10 minutes. According to the record, the cumulative operating time of the multi-connected air-conditioning system from installation and commissioning to operation is 1 year, and the number of fault alarms during the operation of the indoor unit is 3 times. At this time, the time correction parameter A is 1, the fault correction parameter B is 0.9, the indoor unit is in the startup state, the saturation temperature corresponding to the high pressure is 52 °C, and the corresponding high-pressure correction parameter is 0.9. At this time, the sleep cycle of the refrigerant sensor of the indoor unit

[0086] Q = A * B * C * W = 1 * 0.9 * 0.9 * 10 = 8.1.

[0087] After the indoor unit dormancy cycle is determined, the implementation plan is as follows: After the indoor unit refrigerant sensor detects for a period of time t, it enters the dormancy cycle Q. At this time, the indoor unit refrigerant sensor is powered off. After the dormancy cycle ends, it is powered on and runs, entering the leakage detection time. During the power-on detection time t, it is determined whether there is refrigerant leakage based on whether the detected refrigerant concentration reaches the alarm threshold of the refrigerant sensor. When the detected refrigerant concentration reaches the alarm threshold, an alarm is given.

[0088] Figure 4 It is the execution flowchart of the indoor unit dormancy state, including the following steps:

[0089] After calculating the indoor unit dormancy cycle Q, it is judged whether this dormancy cycle is less than the set minimum value T. If so, the dormancy cycle is executed according to this minimum value T; if not, it runs according to the actually calculated dormancy cycle.

[0090] Each time the indoor unit refrigerant sensor detects for a time t, generally 60 seconds. To prevent the refrigerant sensor from switching frequently, the dormancy cycle Q cannot be lower than 1 minute at the lowest. If the dormancy cycle Q is less than 1 minute, it is forced to be executed according to 1 minute.

[0091] When the refrigerant sensor of the indoor unit is powered on and detects for 60 seconds, if the refrigerant sensor of the indoor unit does not alarm, it can be transferred to the dormancy cycle. After continuously powering off for 8.1 minutes, the refrigerant sensor works again after being powered on; if the refrigerant sensor alarms, the refrigerant sensor of the indoor unit has to be powered on all the time until the operator manually resumes it.

[0092] The present invention also proposes an air conditioner multi-connected unit, and its indoor unit adopts the above-mentioned leakage detection method for the combustible refrigerant indoor unit. For a refrigeration and heating system with a large number of indoor units, there are a large number of indoor unit refrigerant sensors. Reducing the working time of the refrigerant sensors can not only reduce energy consumption but also extend the service life of the refrigerant sensors.

[0093] The present invention dynamically adjusts the detection frequency of the indoor unit refrigerant sensor based on various factors such as installation time, operation time, and system parameters, and adopts different detection strategies for the operating states of the powered-on indoor units and powered-off indoor units, which is beneficial to improving economic benefits and reducing energy consumption on the premise of improving reliability.

[0094] The present invention also sets up a safety protection mechanism, which automatically switches to the real-time detection mode when an alarm is detected.

[0095] The leakage detection method of the combustible refrigerant indoor unit proposed by the present invention, the installation and commissioning data, operation data and calculation formulas of the air conditioner multi-connected unit are all compiled in the computer program of the control chip, which can quickly calculate the indoor unit sleep cycle according to the actual operation data and control the refrigerant sensor of the indoor unit to perform intermittent detection, with high efficiency and safety.

[0096] The above are only the specific embodiments of the present invention. It should be noted that any modifications, equivalent replacements and changes made within the spirit and framework of the concept of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting leakage of a combustible refrigerant indoor unit, characterized in that, Comprising: Presetting an initial sleep cycle of the refrigerant sensor of the indoor unit according to design and debugging parameters; Correcting the initial sleep cycle according to the cumulative working time and failure frequency of the indoor unit; Dynamically adjusting the sleep cycle of the refrigerant sensor of the indoor unit according to the operating state of the indoor unit, so that the refrigerant sensor of the indoor unit performs intermittent leakage detection.

2. The leak detection method according to claim 1, wherein, The said correction includes: time correction parameter A, failure correction parameter B, and high-pressure correction parameter C.

3. The leak detection method according to claim 2, wherein Including the following steps: Presetting an initial sleep cycle W of the indoor unit; Selecting the time correction parameter A and the failure correction parameter B of the indoor unit; Judging whether the indoor unit is in the on state. If so, determining the high-pressure correction parameter C according to the high-pressure area of the unit, and then calculating the sleep cycle of the refrigerant sensor of the indoor unit in the on state; if not, calculating the sleep cycle of the refrigerant sensor of the indoor unit in the off state.

4. The leak detection method according to claim 3, wherein, When the indoor unit is in the on state, the sleep cycle Q of the refrigerant sensor of the indoor unit is calculated according to the following formula: Q = A * B * C * W.

5. The leak detection method according to claim 3, characterized in that, When the indoor unit is in the off state, the sleep cycle Q of the refrigerant sensor of the indoor unit is calculated according to the following formula: Q = A * B * N * W, where N is a value greater than 1.

6. The leak detection method according to claim 3, characterized in that, The time correction parameter A of the said indoor unit takes values according to the following table: 。 7. The leak detection method according to claim 3, characterized in that, The failure correction parameter B of the said indoor unit takes values according to the following table: 。 8. The leak detection method according to claim 3, wherein The high-pressure correction parameter C takes values according to the following table: 。 9. The leak detection method according to claim 4 or 5, characterized in that, If the calculated sleep cycle Q is less than 1 minute, it is controlled according to 1 minute.

10. The leak detection method according to claim 1, characterized in that The leakage detection time for each time of the refrigerant sensor of the indoor unit is t.

11. The leak detection method according to claim 3, characterized in that, It also includes the indoor unit sleep execution step: Judging whether the calculated sleep cycle of the indoor unit is less than the minimum value T. If so, the sleep cycle is executed according to the minimum value T; if not, it runs according to the actually calculated sleep cycle.

12. The leak detection method according to claim 11, wherein When the refrigerant sensor of the indoor unit alarms, switch to manual recovery.

13. A multi-connected air conditioner unit, comprising an outdoor unit and an indoor unit, characterized in that, The said indoor unit adopts the leakage detection method of the combustible refrigerant indoor unit according to any one of claims 1-12.

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