Air conditioner and pump flow interruption identification method thereof

Abstract

The application discloses an air conditioner and a pump flow interruption identification method thereof. The pump flow interruption identification method comprises the following steps: when the refrigerant is static, the pressure values of the outlet of the pump and the inlet of the pump are measured to obtain a first pressure difference between the outlet of the pump and the inlet of the pump; after the pump is started, the pressure values of the outlet of the pump and the inlet of the pump are measured in real time to obtain a second pressure difference between the outlet of the pump and the inlet of the pump, and the actual lift of the pump is obtained by adding the second pressure difference and the first pressure difference; and the pump is determined to have flow interruption when the actual lift of the pump is less than a first preset value for more than a first preset time length. The technical scheme provided by the application aims to solve the technical problem that the existing air conditioner has the risk of misjudgment when determining whether flow interruption occurs by using the pressure difference before and after the fluorine pump.

Description

Technical Field

[0001] This invention relates to refrigerant pump disconnection detection technology, specifically to an air conditioner and its pump disconnection identification method. Background Technology

[0002] With increasingly stringent energy efficiency requirements for data centers, in-row air conditioning systems need to improve the utilization of natural cooling sources. Using refrigerant pumps for natural cooling can effectively improve unit energy efficiency.

[0003] However, existing air conditioning refrigerant pump units use Freon as the working fluid. When the refrigerant at the pump inlet is subjected to pressure and / or temperature changes, it is easy to vaporize, which can cause the refrigerant pump to stop flowing, resulting in the air conditioning system not circulating refrigerant, and causing insufficient cooling capacity and dry running and friction problems of the refrigerant pump. Summary of the Invention

[0004] Currently, inter-row air conditioners with refrigerant pump systems mainly determine whether the refrigerant flow is interrupted based on the pressure difference before and after the refrigerant pump. However, this has the following problems:

[0005] 1. In compressor mode, the pressure at the refrigerant pump is relatively high. The measurement range of the low-pressure sensor is not large enough, while the measurement accuracy of the high-pressure sensor is not high enough. If the measurement accuracy of the pressure sensor is not high enough, there is a risk of misjudging whether the flow is interrupted by using the pressure difference before and after the refrigerant pump.

[0006] 2. When there is a long piping connection between the indoor and outdoor units, or when the outdoor unit is below the indoor unit and the height difference between the indoor and outdoor units is too large, the head of the refrigerant pump may be too large before and after the flow is interrupted, and the flow interruption cannot be detected.

[0007] The main objective of this invention is to provide a method for identifying pump interruption in air conditioners, aiming to solve the technical problem that existing air conditioners rely on the pressure difference before and after the refrigerant pump to determine whether the pump is interrupted, which carries the risk of misjudgment.

[0008] To achieve the above objectives, the present invention proposes a method for identifying pump interruption in an air conditioner, comprising:

[0009] When the refrigerant is stationary, measure the pressure values ​​at the pump outlet and pump inlet to obtain the first pressure difference between the pump outlet and pump inlet;

[0010] After the pump is started, the pressure values ​​at the pump outlet and pump inlet are measured in real time to obtain the second pressure difference between the pump outlet and pump inlet. The second pressure difference is added to the first pressure difference to obtain the actual head of the pump.

[0011] If the actual head of the pump is less than the first preset value for more than the first preset time, it is confirmed that the pump has stopped flowing.

[0012] In one illustrative embodiment, a first pressure sensor and a second pressure sensor are used to measure the pressure values ​​at the pump inlet and outlet, respectively. The range of the first preset value Pset is:

[0013] a1+a2+0.03bar≤Pset≤a1+a2+0.06bar;

[0014] Where a1 is the tolerance value of the first pressure sensor and a2 is the tolerance value of the second pressure sensor.

[0015] In one illustrative embodiment, when the refrigerant is stationary, measuring the pressure values ​​at the pump outlet and pump inlet to obtain a first pressure difference between the pump outlet and pump inlet includes:

[0016] When the refrigerant is stationary, the pressure values ​​at the pump outlet and pump inlet are measured for a second preset duration, and the first pressure difference is the average value of the pressure difference between the pump outlet and pump inlet within the second preset duration.

[0017] In one illustrative embodiment, when the refrigerant is stationary, the pressure values ​​at the outlet and inlet of the measuring pump are triggered by the power-on operation of the air conditioner.

[0018] In one illustrative embodiment, it also includes:

[0019] After confirming that the pump has stopped flowing, send a flow interruption alarm message.

[0020] In one illustrative embodiment, it also includes:

[0021] After starting the pump, measure the first temperature at the pump outlet;

[0022] The subcooling of the refrigerant at the pump outlet is determined based on the first temperature and the pressure at the pump outlet when the first temperature is measured.

[0023] Based on the fact that the subcooling is greater than or equal to the saturation temperature of the refrigerant corresponding to the pressure that the pump can increase when pumping the refrigerant at its minimum head, it is confirmed that the pump has stopped flowing.

[0024] In one illustrative embodiment, determining the subcooling of the refrigerant at the pump outlet based on the first temperature and the pressure at the pump outlet when the first temperature is measured includes:

[0025] The saturation temperature of the refrigerant at that pressure is obtained by measuring the pressure at the pump outlet when the first temperature is measured.

[0026] The supercooling is obtained by subtracting the saturation temperature from the first temperature.

[0027] In one illustrative embodiment, the pump outlet and inlet pressure values ​​are measured in real time only after a third preset time interval following pump startup; and / or,

[0028] The first temperature at the pump outlet is measured only after a third preset time interval following pump startup.

[0029] In one illustrative embodiment, it also includes:

[0030] If the difference between the actual head of a pump and the actual head of the pump at the current time is greater than the second preset value within the fourth preset time period before the current time, and there is an actual head of a pump that satisfies formula (1) within the time range between the first time and the second time after the current time, then it is confirmed that the pump has stopped flowing.

[0031] △P <A×△P_t2 (1)

[0032] Wherein, △P is the actual head of any pump within the time range, △P_t2 is the actual head of the pump during the fourth preset time period before the current moment, and the value of A is 0.4≤A≤0.8.

[0033] In one illustrative embodiment, it also includes:

[0034] Based on the fact that within a fourth preset time period before the current moment, the difference between the actual head of a pump and the actual head of the pump at the current moment is greater than a second preset value, and the difference between the maximum value and the minimum value of the actual head of the pump within the time range between the first time and the second time after the current moment is greater than a third preset value.

[0035] In one illustrative embodiment, the second preset value Ps2 ranges from 1 bar to 2 bar; and / or,

[0036] The fourth preset duration t2 has a value range of 30s ≤ t2 ≤ 60s; and / or,

[0037] The first time interval t3 is in the range of 60s ≤ t3 ≤ 80s; and / or,

[0038] The second time t4 ranges from 100s ≤ t4 ≤ 120s; and / or,

[0039] The range of the third preset value Ps3 is 1 bar ≤ Ps3 ≤ 2 bar.

[0040] This application also proposes an air conditioner, which includes:

[0041] Condenser;

[0042] Evaporator;

[0043] A pump, connected to the condenser and the evaporator via pipelines, is used to drive the refrigerant to circulate between the condenser and the evaporator, and has an inlet and an outlet;

[0044] A first pressure sensor is located at the inlet;

[0045] A second pressure sensor is located at the outlet;

[0046] A temperature sensor is located at the outlet;

[0047] The controller, electrically connected to the first pressure sensor, the second pressure sensor, and the temperature sensor, is configured to perform the pump disconnection identification method as described above.

[0048] In this invention, the actual pump head is obtained by adding the second pressure difference and the first pressure difference. This actual head eliminates the influence of measurement errors from the pressure sensor.

[0049] If the pump's actual head is less than the first preset value for a duration that is greater than or equal to the first preset duration, it can be confirmed that the pump has stopped flowing.

[0050] If the duration for which the actual pump head is less than the first preset value is less than the first preset duration, it may be due to pressure fluctuations of the liquid refrigerant before and after the pump in motion. Setting the condition for judging whether the pump has stopped flowing to the actual pump head being above the first preset value can eliminate the misjudgment caused by pressure fluctuations of the liquid refrigerant.

[0051] Furthermore, since the actual pump head is obtained by adding the second pressure difference to the first pressure difference, the influence of the measurement error of the pressure sensor can be eliminated. Therefore, this pump flow interruption identification method can accurately determine whether the pump has stopped flowing. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the structure of an air conditioner according to an embodiment of this application;

[0054] Figure 2 This is a flowchart of a pump disconnection identification method for an air conditioner according to an embodiment of this application;

[0055] Figure 3 This is a pressure curve of the pump inlet and outlet in an embodiment of this application.

[0056] Explanation of icon numbers:

[0057] 1. Pump; 2. Throttling element; 3. Evaporator; 4. Condenser; 5. Liquid receiver; 6. First pressure sensor; 7. Second pressure sensor; 8. Temperature sensor.

[0058] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0060] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0061] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0064] like Figure 1 As shown, Figure 1 The diagram illustrates the structure of an air conditioner. This air conditioner can be an in-row air conditioner. It includes a pump 1, a throttling element 2, an evaporator 3, a condenser 4, and a liquid receiver 5. The outlet of pump 1 is connected to the inlet of throttling element 2 via a pipeline. The outlet of throttling element 2 is connected to the inlet of evaporator 3 via a pipeline. The outlet of evaporator 3 is connected to condenser 4 via a pipeline. Condenser 4 is connected to the inlet of liquid receiver 5 via a pipeline. The outlet of liquid receiver 5 is connected to the inlet of pump 1. The piping of this refrigeration system contains a refrigerant, which can be a Freon refrigerant.

[0065] Pump 1 can be an impeller pump, such as a centrifugal pump, axial flow pump, or mixed flow pump. Pump 1 can also be a positive displacement pump, such as a gear pump or piston pump. During operation, pump 1 draws in liquid refrigerant from the inlet, pressurizes it, and then outputs it from the outlet. The refrigerant flows back into pump 1 after passing through the throttling element 2, evaporator 3, condenser 4, and receiver 5. When the outdoor ambient temperature is low, the natural air is an abundant source of cooling. The refrigerant absorbs heat from the indoor air as it passes through evaporator 3, and releases this heat into the outdoor air as it passes through condenser 4, thus achieving cooling. Compared to using a compressor alone, this cooling method is significantly more energy-efficient.

[0066] The air conditioner also includes a detection component and a controller. The detection component includes a first pressure sensor 6, a second pressure sensor 7, and a temperature sensor 8. The first pressure sensor 6 is located at the inlet of pump 1 and is used to detect the pressure at the inlet of pump 1. The second pressure sensor 7 is located at the outlet of pump 1 and is used to detect the pressure at the outlet of pump 1. The temperature sensor 8 is located at the outlet of pump 1 and is used to detect the refrigerant temperature at the outlet of pump 1.

[0067] The controller is the logic control unit of the air conditioner and can be a microcontroller. The controller is electrically connected to the first pressure sensor 6, the second pressure sensor 7, the temperature sensor 8, and the pump 1.

[0068] like Figure 2 As shown, this application also proposes a method for identifying pump interruption in an air conditioner, which is implemented based on the air conditioner described above. The pump interruption identification method includes the following steps:

[0069] Step S1: When the refrigerant is stationary, measure the pressure values ​​at the outlet and inlet of pump 1 to obtain the first pressure difference between the outlet and inlet of pump 1, and proceed to step S2;

[0070] Before the air conditioner begins cooling, the refrigerant is stationary. The controller drives the first pressure sensor 6 to measure the first pressure at the inlet of pump 1, and also drives the second pressure sensor 7 to measure the second pressure at the outlet of pump 1. The first pressure difference can be equal to the difference between the second pressure and the first pressure.

[0071] Ideally, before the air conditioner begins cooling, the pressure at the outlet and inlet of pump 1 are balanced, and the pressure difference between the outlet and inlet of pump 1 is theoretically zero. However, due to errors in the measurement of both the first pressure sensor 6 and the second pressure sensor 7, the measurement results of the first pressure sensor 6 and the second pressure sensor 7 will be different before the air conditioner begins cooling. Therefore, the first pressure difference between the outlet and inlet of pump 1 reflects the measurement errors of the first pressure sensor 6 and the second pressure sensor 7.

[0072] Step S2: After starting pump 1, measure the pressure values ​​at the outlet and inlet of pump 1 in real time to obtain the second pressure difference between the outlet and inlet of pump 1. Add the second pressure difference to the first pressure difference to obtain the actual head of pump 1, and proceed to step S3.

[0073] Users can send a cooling mode command for Pump 1 to the air conditioner via remote control, smart terminal, or the air conditioner's control panel. The cooling mode command instructs Pump 1 to operate, enabling the air conditioner to cool. Upon receiving the cooling mode command, the controller drives Pump 1 to start operation. After starting, Pump 1 draws refrigerant in from its inlet, pressurizes it, and outputs it from its outlet, allowing the refrigerant to circulate between the condenser 4 and the evaporator 3.

[0074] During the operation of pump 1, the controller drives the first pressure sensor 6 to measure the third pressure value at the inlet of pump 1 in real time and records the first curve of the third pressure value changing over time. At the same time, the controller also drives the second pressure sensor 7 to measure the fourth pressure value at the outlet of pump 1 in real time and records the second curve of the fourth pressure value changing over time. The controller subtracts the fourth pressure value from the third pressure value at the same moment to obtain the second pressure difference at that moment.

[0075] The controller adds the second pressure difference and the first pressure difference at each moment to obtain the actual head of pump 1 at each moment. This actual head eliminates the influence of measurement errors from the first pressure sensor 6 and the second pressure sensor 7.

[0076] Step S3: Determine whether the actual head of pump 1 is less than the first preset value for more than the first preset time. If so, proceed to step S4; otherwise, proceed to step S3.

[0077] Step S4: Confirm that pump 1 has stopped flowing.

[0078] The first preset value is an empirical value, slightly greater than the pressure difference between the outlet and inlet of pump 1 when the flow suddenly stops during operation. This pressure difference can be pre-calibrated, and then the first preset value can be set to be slightly greater than this pressure difference. When pump 1 is an impeller pump 1, especially a centrifugal pump 1, the pressure difference between its outlet and inlet is close to zero when the flow stops. In this case, the first preset value can be set to be slightly greater than zero.

[0079] The first preset duration is an empirical value, which can be 1 to 4 seconds.

[0080] The actual head of pump 1 fluctuates over time. The controller starts timing each time the actual head of pump 1 is less than the first preset value. When the actual head of pump 1 is greater than or equal to the first preset value, the timing stops. When the timing duration reaches more than the first preset duration, it is confirmed that the duration for which the actual head of pump 1 is less than the first preset value is greater than or equal to the first preset duration.

[0081] When the actual head of pump 1 is less than the first preset value for a duration that is greater than or equal to the first preset duration, the controller confirms that pump 1 has stopped flowing.

[0082] When the actual head of pump 1 is less than the first preset value for a duration less than the first preset time, it may be due to pressure fluctuations of the liquid refrigerant before and after pump 1 during operation. Setting the condition for determining whether pump 1 has stopped flowing as an actual head of pump 1 being above the first preset value can eliminate false judgments caused by pressure fluctuations of the liquid refrigerant. Furthermore, since the actual head of pump 1 is obtained by adding the second pressure difference to the first pressure difference, the influence of measurement errors of the first pressure sensor 6 and the second pressure sensor 7 can be eliminated. Therefore, this pump stoppage identification method can accurately determine whether pump 1 has stopped flowing.

[0083] In one illustrative embodiment, a first pressure sensor 6 and a second pressure sensor 7 are used to measure the pressure values ​​at the inlet and outlet of pump 1, respectively. The range of the first preset value Pset is:

[0084] a1+a2+0.03bar≤Pset≤a1+a2+0.06bar

[0085] Where a1 is the tolerance value of the first pressure sensor 6 and a2 is the tolerance value of the second pressure sensor 7.

[0086] The tolerance value is the maximum allowable deviation between the sensor's output value and the measured true value. The tolerance value of the first pressure sensor 6 is the maximum allowable error of the first pressure sensor 6, and the tolerance value of the second pressure sensor 7 is the maximum allowable error of the second pressure sensor 7. When setting the first preset value, taking into account the tolerance values ​​of both the first pressure sensor 6 and the second pressure sensor 7 can improve the accuracy of determining whether pump 1 has experienced a flow interruption based on the first preset value.

[0087] In an illustrative embodiment, step S1 specifically includes: when the refrigerant is stationary, measuring the pressure values ​​of the outlet and inlet of pump 1 for a second preset duration, calculating the average value of the pressure difference between the outlet and inlet of pump 1 within the second preset duration, and using the average value as the first pressure difference.

[0088] The second preset duration can be 5 to 10 seconds. By calculating the average pressure difference between the outlet and inlet of pump 1 within the second preset duration, and using this average value as the first pressure difference, the measurement error of the first temperature sensor 8 and the second temperature sensor 8 can be more accurately reflected.

[0089] In an illustrative embodiment, in step S1, the power-on operation of the air conditioner triggers the measurement of the pressure values ​​at the outlet and inlet of pump 1 to obtain a first pressure difference between the outlet and inlet of pump 1.

[0090] Each time the air conditioner is powered on, the controller immediately and automatically drives the first pressure sensor 6 and the second pressure sensor 7 to measure the first pressure at the inlet of pump 1 and the second pressure at the outlet of pump 1, respectively.

[0091] When the air conditioner is first powered on, the refrigerant inside is typically in a static state. This ensures that the refrigerant remains stationary when the pressure values ​​at the outlet and inlet of pump 1 are measured. Furthermore, the air conditioner automatically performs measurements upon power-on, eliminating the need to measure and calculate the initial pressure difference only after the user issues a command to switch pump 1 to cooling mode, thus reducing user waiting time. In particular, the automatic calibration of the measurement errors of the first and second temperature sensors 8 each time the air conditioner is powered on improves the accuracy of subsequent determinations regarding whether pump 1 has experienced a flow interruption.

[0092] In one illustrative embodiment, the pump flow interruption identification method further includes steps S5, S6, and S7;

[0093] Step S5: After starting pump 1, measure the first temperature at the outlet of pump 1, and proceed to step S6;

[0094] The controller also drives temperature sensor 8 to measure the initial temperature at the outlet of pump 1.

[0095] Step S6: Determine the subcooling of the refrigerant at the outlet of pump 1 based on the first temperature and the pressure at the outlet of pump 1 when the first temperature is measured, and proceed to step S7.

[0096] Since the second pressure sensor 7 also measures the second pressure at the outlet of pump 1 in real time during step S2, the controller can obtain the second pressure at the same time when driving the temperature sensor 8 to measure the first temperature at the outlet of pump 1.

[0097] The pressure rise process of pump 1 is simplified as an isothermal pressure rise process. The correspondence between refrigerant pressure and saturation temperature can be obtained from a table. The controller can obtain the saturation temperature of the refrigerant at the second pressure based on the second pressure at the outlet of pump 1 when the first temperature is measured. The controller subtracts the saturation temperature of the refrigerant at the second pressure from the first temperature to obtain the subcooling of the refrigerant at the outlet of pump 1.

[0098] Step S7: Determine whether the subcooling of the refrigerant at the outlet of pump 1 is greater than or equal to the saturation temperature of the refrigerant corresponding to the pressure that pump 1 can increase when pumping the refrigerant at its minimum head. If yes, proceed to step S4; otherwise, proceed to step S5.

[0099] The minimum head of pump 1 is predetermined by the pump's own performance and the air conditioner's performance specifications during the air conditioner design process; it is a known value. The pressure that pump 1 can raise when pumping refrigerant at its minimum head is an empirical value and can be pre-calibrated. Furthermore, the correspondence between refrigerant pressure and saturation temperature can be obtained from a table. Therefore, the controller can look up the corresponding refrigerant saturation temperature based on the pressure that pump 1 can raise when pumping refrigerant at its minimum head. The controller determines that pump 1 has stopped flowing when it detects that the subcooling of the refrigerant at the outlet of pump 1 is greater than or equal to this saturation temperature.

[0100] By comparing the subcooling of the refrigerant at the outlet of pump 1 with the saturation temperature of the refrigerant corresponding to the pressure that pump 1 can increase when pumping the refrigerant at its minimum head, it is possible to determine whether pump 1 has stopped flowing, making the judgment of pump 1's flow interruption more accurate and comprehensive.

[0101] In an illustrative embodiment, in step S2, the pressure values ​​at the outlet and inlet of pump 1 are measured in real time only after a third preset time interval following the start of pump 1; and / or, in step S5, the first temperature at the outlet of pump 1 is measured only after a third preset time interval following the start of pump 1.

[0102] The third preset duration can be 1 to 3 minutes.

[0103] After pump 1 has been running for three preset durations, the air conditioner’s refrigeration system is running smoothly and the pressure in the refrigeration system tends to be stable. Only then do we start measuring the pressure values ​​at the outlet and inlet of pump 1, as well as the first temperature at the outlet of pump 1. This allows for a more accurate determination of whether pump 1 has stopped flowing.

[0104] In one illustrative embodiment, such as Figure 3 As shown, the pump flow interruption identification method also includes steps S8 to S10 after step S2;

[0105] Step S8: Determine whether there exists a difference between the actual head of pump 1 and the actual head of pump 1 at the current time within the fourth preset time t2 before the current time t0, which is greater than the second preset value Ps2. If so, proceed to step S9; otherwise, proceed to step S8.

[0106] The second preset value Ps2 has a range of 1 bar ≤ Ps2 ≤ 2 bar. The fourth preset duration t2 has a range of 30 s ≤ t2 ≤ 60 s.

[0107] Step S9: Determine whether, within the time range Δt between the first time t3 and the second time t4 after the current time t0, there exists an actual head ΔP of pump 1 that satisfies the following formula:

[0108] △P <A×△P_t2;

[0109] If yes, proceed to step S4; otherwise, proceed to step S10.

[0110] Wherein, △P is the actual head of pump 1 at any time within the time range Δt between the first time t3 and the second time t4, △P_t2 is the actual head of pump 1 at the fourth preset time t2 before the current time t0, and A is the adjustment coefficient, with the value range of 0.4≤A≤0.8.

[0111] The second time interval t4 is longer than the first time interval t3. The range of the first time interval t3 is 60s ≤ t3 ≤ 80s. The range of the second time interval t4 is 100s ≤ t4 ≤ 120s.

[0112] If, within the time range Δt between the first time point t3 and the second time point t4, there exists an actual head ΔP that satisfies the above inequality, then the actual head of pump 1 is considered to be decreasing at an excessively rapid rate, and the controller confirms that pump 1 has experienced a flow interruption. Thus, determining whether pump 1 has experienced a flow interruption by monitoring the rate of decrease in the actual head of pump 1 avoids situations where flow interruptions cannot be detected due to long piping connections between the indoor and outdoor units, or when the outdoor unit is below the indoor unit and the height difference between the two units is too large. Therefore, using this method to confirm whether pump 1 has experienced a flow interruption is more accurate and comprehensive.

[0113] Step S10: Determine whether the difference between the maximum value of the actual head of pump 1 and the minimum value of the actual head of pump 1 within the time range Δt between the first time t3 and the second time t4 after the current time t0 is greater than the third preset value Ps3. If yes, proceed to step S4; otherwise, proceed to step S8.

[0114] The third preset value Ps3 has a range of 1 bar ≤ Ps3 ≤ 2 bar.

[0115] If the difference between the maximum and minimum actual head of pump 1 within the time range Δt exceeds the third preset value Ps3, it is considered that the rate of decrease in the actual head of pump 1 is too fast, and the controller confirms that pump 1 has stopped flowing. In this way, determining whether pump 1 has stopped flowing by monitoring the rate of decrease in the actual head of pump 1 avoids situations where flow interruptions cannot be detected due to long piping connections between the indoor and outdoor units, or when the outdoor unit is below the indoor unit and the height difference between the two units is too large. Therefore, this method of confirming whether pump 1 has stopped flowing is more accurate and comprehensive.

[0116] In one illustrative embodiment, the air conditioner also includes an alarm module. The alarm module is used to send out a flow interruption alarm message. The alarm module can be a visual or audible alarm, a speaker, a display screen, an alarm light, or a communication module. The alarm module is electrically connected to the controller.

[0117] Step S4 also includes sending a flow interruption alarm message after confirming that the flow interruption has occurred in pump 1.

[0118] After confirming that pump 1 has interrupted flow, the controller sends a flow interruption alarm message to the user or maintenance personnel via the alarm device. The flow interruption alarm message can be sent out in the form of graphic or audio-visual information.

[0119] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for identifying pump disconnection in an air conditioner, characterized in that, include: When the refrigerant is stationary, measure the pressure values ​​at the pump outlet and pump inlet to obtain the first pressure difference between the pump outlet and pump inlet; After the pump is started, the pressure values ​​at the pump outlet and pump inlet are measured in real time to obtain the second pressure difference between the pump outlet and pump inlet. The second pressure difference is added to the first pressure difference to obtain the actual head of the pump. If the actual pump head is less than the first preset value and continues for more than the first preset duration, it is confirmed that the pump has stopped flowing.

2. The pump flow interruption identification method according to claim 1, characterized in that, The first pressure sensor and the second pressure sensor are used to measure the pressure values ​​at the pump inlet and outlet, respectively. The range of the first preset value Pset is: a1+a2+0.03bar≤Pset≤a1+a2+0.06bar; Where a1 is the tolerance value of the first pressure sensor and a2 is the tolerance value of the second pressure sensor.

3. The pump flow interruption identification method according to claim 1, characterized in that, Measuring the pressure values ​​at the pump outlet and pump inlet to obtain a first pressure difference between the pump outlet and pump inlet includes: The pressure values ​​at the pump outlet and pump inlet are measured for a second preset time, and the average value of the pressure difference between the pump outlet and pump inlet within the second preset time is determined as the first pressure difference.

4. The pump flow interruption identification method according to claim 1, characterized in that, When the refrigerant is stationary, the pressure values ​​at the outlet and inlet of the measuring pump are triggered by the power-on operation of the air conditioner.

5. The pump flow interruption identification method according to claim 1, characterized in that, Also includes: After confirming that the pump has stopped flowing, send a flow interruption alarm message.

6. The pump flow interruption identification method according to any one of claims 1 to 5, characterized in that, Also includes: After starting the pump, measure the first temperature at the pump outlet; The subcooling of the refrigerant at the pump outlet is determined based on the first temperature and the pressure at the pump outlet when the first temperature is measured. Based on the fact that the subcooling is greater than or equal to the saturation temperature of the refrigerant corresponding to the pressure that the pump can increase when pumping the refrigerant at its minimum head, it is confirmed that the pump has stopped flowing.

7. The pump flow interruption identification method according to claim 6, characterized in that, The determination of the subcooling of the refrigerant at the pump outlet based on the first temperature and the pressure at the pump outlet when the first temperature is measured includes: The saturation temperature of the refrigerant at that pressure is obtained by measuring the pressure at the pump outlet when the first temperature is measured. The supercooling is obtained by subtracting the saturation temperature from the first temperature.

8. The pump flow interruption identification method according to claim 6, characterized in that, After the pump is started, the pressure values ​​at the pump outlet and inlet are measured in real time only after a third preset time interval; and / or, The first temperature is measured only after a third preset time interval following pump startup.

9. The pump flow interruption identification method according to any one of claims 1 to 5, characterized in that, Also includes: Based on the fact that the difference between the actual head of a pump and the actual head of the pump at the current time is greater than the second preset value within the fourth preset time period before the current time, and there is an actual head of a pump that satisfies formula (1) within the time range between the first time and the second time after the current time, it is confirmed that the pump has stopped flowing. △P <A×△P_t2 (1) Wherein, △P is the actual head of any pump within the time range, △P_t2 is the actual head of the pump during the fourth preset time period before the current moment, and the value of A is 0.4≤A≤0.

8.

10. The pump flow interruption identification method according to any one of claims 1 to 5, characterized in that, Also includes: Based on the fact that the difference between the actual head of the pump and the actual head of the pump at the current moment is greater than a second preset value within a fourth preset time period before the current moment, and the difference between the maximum value and the minimum value of the actual head of the pump within the time range between the first time and the second time after the current moment is greater than a third preset value, it is confirmed that the pump has stopped flowing.

11. An air conditioner, characterized in that, include: Condenser; Evaporator; A pump, connected to the condenser and the evaporator via pipelines, is used to drive the refrigerant to circulate between the condenser and the evaporator, and has an inlet and an outlet; A first pressure sensor is located at the inlet; A second pressure sensor is located at the outlet; as well as The controller, electrically connected to the first pressure sensor, the second pressure sensor, and the temperature sensor, is configured to perform the pump disconnection identification method as described in any one of claims 1 to 10.

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