Air conditioning device and refrigerant leak detection method therefor

Abstract

An air conditioning device and a refrigerant leak detection method. The air conditioning device comprises: a first refrigerant circulation loop and a second refrigerant circulation loop, the circulation loops both comprising condensers (3-1, 3-2), throttling apparatuses (6-1, 6-2), evaporators (7-1, 7-2), and a compressor (1a); and a leak detection unit, comprising a first temperature sensor configured to measure the temperature of the first refrigerant circulation loop, a second temperature sensor configured to measure the temperature of the second refrigerant circulation loop, and a control assembly configured to receive a first temperature measured by the first temperature sensor and a second temperature measured by the second temperature sensor, and compare a temperature difference between the first temperature and the second temperature with a temperature reference threshold, so as to generate a signal for determining a refrigerant leak condition.

Description

The air conditioning unit also includes a leak detection unit. The leak detection unit includes condenser temperature sensors 11-1 and 11-2; and evaporator temperature sensors 12-1 and 12-2. Condenser temperature sensor 11-1 and evaporator temperature sensor 12-1 are connected to condenser  3-1  and evaporator 7-1  respectively in the first refrigerant circulation loop to measure the temperature Tx1 at condenser 3-1 and the temperature Ti1 at evaporator 7-1. Condenser temperature sensor 11-2 and evaporator temperature sensor 12-2 are connected to condenser 3-2 and evaporator 7-2 respectively in the second refrigerant circulation loop to measure the temperature Tx2 at condenser 3-2 and the temperature Ti2 at evaporator 7-2. The leakage unit also includes exhaust temperature sensors 10-1 and 10-2, which measure the exhaust temperature Td1 of the first refrigerant circulation loop and the exhaust temperature Td2 of the second refrigerant circulation loop, respectively. The leak detection unit also includes pressure sensors 13-1 and 13-2. Pressure sensors 13-1 and 13-2 are configured to measure the pressure P1 of the first refrigerant circulation loop and the pressure P2 of the second refrigerant circulation loop, respectively. The leak detection unit includes a control component (not shown) connected to a refrigerant sensor and configured to receive data from the refrigerant sensor (e.g., in real time). The control component may include a printed circuit board (PCB). The control component receives temperature data from a first refrigerant circulation loop and a second refrigerant circulation loop measured by a temperature sensor and compares the temperature difference between the two loops with a temperature reference threshold stored in a memory to generate a signal for determining a refrigerant leak. The control component is also connected to a memory. This memory may or may not be included in the air conditioning unit. The control component is configured to compare real-time received data with a reference threshold stored in the memory and generate a signal reflecting the refrigerant leak status. For example, the control component can be configured to generate an alarm signal if the difference between the received data and the reference threshold exceeds the threshold. Therefore, the control component can be configured to monitor the refrigerant leak status, allowing for rapid identification of leaks once they occur. In cooling mode, if at least two of the following conditions are met: | Td1 -Td2 | > A1, | Tx1 -Tx2 | > B1, | P1-P2 | > C1, a leak is determined to have occurred, and the solenoid valve is shut off by the control component to prevent refrigerant from entering the evaporator. In heating mode, if at least two of the following conditions are met: Td1 -Td2 | > A2, | Tx1 - Tx2 | > B2, | P1-P2 | > C2, a leak is determined to have occurred, and the solenoid valve is shut off by the control component to prevent refrigerant from entering the condenser. In this embodiment, the presence of refrigerant leakage during the shutdown process of the air conditioning unit can be determined by detecting the pressure of the refrigeration equipment before startup. For example, if | P1-P2 | > C3 when the air conditioning unit is not running (powered on but compressor not running), then a leak is determined to have occurred. Among them, A1, A2, B1, and B2 refer to temperature differences, which are used to determine refrigerant leaks; C1, C2, and C3 refer to refrigerant pressure differences, which are used to determine refrigerant leaks. In the embodiments, A1 is approximately 1.0 °C to 15.0 °C, A2 is approximately 1.0OC to 20.0°C, and A1 is less than A2. For example, if A1 is 1 C, then A2 is 1.5 C. B1 is approximately 1.0 C to 10.0 C, B2 is approximately 1.0C to 15.0C, and B1 is less than B2. For example, if B1 is 1C, then B2 is 1.5C. C1 is approximately 0.01 MPa to 0.5 MPa, C2 is approximately 0.01 MPa to 1.0 MPa, and C3 is approximately 0.01 MPa to 0.6 MPa. C1 < C2 < C3. For example, if C1 is 0.01 MPa, then C2 is 0.02 MPa, and C3 is 0.1 MPa. In this embodiment, the first refrigerant circulation loop and the second refrigerant circulation loop are two identical independent refrigerant circulation loops. By comparing the differences in real-time temperature and pressure parameters, the dual refrigerant circulation loops can promptly identify refrigerant leaks. Furthermore, the dual circulation loop system can reduce the leakage of flammable refrigerant; even if a leak occurs in one of the refrigerant circulation loops, the maximum leakage rate of the entire air conditioning refrigerant is only 50%. Because the structures and refrigerant injection rates of the dual refrigerant circulation loops are basically the same,  the  amounts of evaporating and condensing air are essentially the same, and the displacements of the two compressors under the same motor are also the same, under normal circumstances, their discharge temperature, condensing temperature, evaporating temperature, and refrigerant  pressure  in both refrigerant circulation loops should be the same, or have only very small deviations. When a refrigerant leak occurs in one of the refrigerant circulation loops, the discharge temperature, condensing temperature, evaporating temperature, and refrigerant pressure of that loop will all change to varying degrees. By comparing some or all of the parameters of this loop with those of the normal loop, a refrigerant leak can be quickly identified. The air conditioning equipment in this embodiment can detect flammable refrigerant leaks in a timely manner, thus providing users with more reliable protection. Furthermore, the dual refrigerant circulation loop can increase the upper limit of flammable refrigerant charge, thereby providing better air conditioning performance; and it meets the safety regulations for low-GWP refrigerants (R290, etc.), making it suitable for more markets. In the air conditioning equipment shown in Figure 1, the refrigerant passing through compressor 1a bypasses the motor cavity; after compression, the refrigerant is directly discharged from the compressor through discharge ports 15a-1 and 15a-2. However, the technology disclosed herein is not limited to this. Compressor 1a can have different heat dissipation methods. For example, in one of the two refrigerant circulation loops of compressor 1a, the refrigerant is compressed and discharged from the motor cavity through discharge port 15a-1 to cool the motor. In the other refrigerant circulation loop, the refrigerant is compressed and discharged directly from the compressor through discharge port 15a-2. In the embodiment shown in Figure 1, compressor 1a is a two-cylinder compressor, wherein one cylinder of the compressor is connected in a first refrigerant circulation loop; and the other cylinder of the compressor is connected in a second refrigerant circulation loop. However, the technology disclosed herein is not limited to this and can be applied to two single-cylinder compressors. Figure 2 illustrates an air conditioning unit comprising two singlecylinder compressors according to an embodiment of the present disclosure. Figure 2, the air conditioning unit includes two single-cylinder compressors, one of which is connected in the first refrigerant circulation loop; the other single-cylinder compressor is connected in the second refrigerant circulation loop. Other components are the same as in the embodiment shown in Figure 1, and will not be described again here. Figure 3 shows a flowchart of a method for detecting refrigerant leakage in an air conditioning unit according to an embodiment of the present disclosure. When the air conditioning unit is not running (powered on but compressor not running), the pressures of the first refrigerant circulation loop (P1) and the second refrigerant circuit (P2) measured by pressure sensors 13-1 and 13-2 are used to determine whether there is a refrigerant leak during the shutdown process. For example, if | P1-P2 | > C3, a leak is confirmed, and an alarm signal is sent, where C3 is approximately 0.01 MPa to 0.6 MPa. When the air conditioning equipment is running, the method includes measuring the temperature Tx1 at the condenser 3-1 in the first refrigerant circulation loop and the temperature Tx2 at the condenser 3-1 in the second refrigerant circulation loop using condenser temperature sensors 11 -1 and 11-2 respectively ; measuring the temperature Ti1 at the evaporator 7-1 in the first refrigerant circulation loop and the temperature Ti2 at the evaporator 7-2 in the second refrigerant circulation loop using evaporator temperature sensors 12-1 and 12-2 respectively ; and measuring the exhaust temperature Td1 of the first refrigerant circulation loop and the exhaust temperature Td2 of the second refrigerant circulation loop using exhaust temperature sensors 10-1 and 10-2 respectively. The measured temperatures Tx1, Tx2, Ti1, Ti2, Td1, and Td2 are sent to a control component connected to the temperature sensor. The control component reads the stored temperature reference threshold from the memory and compares the differences between Tx1 and Tx2, Ti1 and Ti2, and Td1 and Td2 with the temperature reference threshold respectively. In cooling mode, if at least one of | Td1 -Td2 | > A1 and | Tx1 -Tx2 | > B1 is satisfied, a leak is determined, and an alarm signal is sent through the control component and the solenoid valve is closed to prevent refrigerant from entering the evaporator. In heating mode, if at least one of | Td1 -Td2 | > A2 and | Tx1 -Tx2 | > B2 is satisfied, a leak is determined, and an alarm signal is sent through the control component and the solenoid valve is closed to prevent refrigerant from entering the condenser. In an embodiment, the method may further include measuring the pressure P1 of the first refrigerant circulation loop and the pressure P2 of the second refrigerant circulation loop using pressure sensor 13-1 and pressure sensor 13-2, respectively. The measured pressures P1 and P2 are sent to a control unit connected to the pressure sensor. The control unit reads a stored pressure reference threshold from the memory and compares the difference between P1 and P2 with the pressure reference threshold. In cooling mode, if | P1-P2 | > C1, a leak is detected, and the control unit sends an alarm signal and closes the solenoid valve to prevent refrigerant from entering the evaporator. In heating mode, if | P1-P2 | > C2, a leak is detected, and an alarm signal is sent through the control components and the solenoid valve is closed to prevent refrigerant from entering the condenser. A1, A2, B1, and B2 refer to temperature differences, used to determine refrigerant leaks; C1, C2, and C3 refer to refrigerant pressure differences, used to determine refrigerant leaks. In the embodiments, A1 is approximately 1.0 OC to 15.0 °C, A2 is approximately 1.0C to 2().()°C, and A1 is less than A2. For example, if A1 is 1C, then A2 is 1.5C. B1 is approximately 1.0 C to 10.0C, B2 is approximately 1.0C to 15.0C, and B1 is less than B2. For example, if B1 is 1C, then B2 is 1.5C. C1 is approximately 0.01 MPa to 0.5 MPa, C2 is approximately 0.01 MPa to 1.0 MPa, and C3 is approximately 0.01 MPa to 0.6 MPa. C1 < C2 < C3. For example, if C1 is 0.01 MPa, then C2 is 0.02 MPa, and C3 is 0.1 MPa. Compared with well-known detection methods that use refrigerant sensors on the internal heat exchanger side, the technology disclosed herein can detect leaks at any location in air conditioning equipment, thus providing higher safety. Furthermore, the terms “first” and “second” are used only to distinguish each other for descriptive purposes and should not be construed as indicating or implying relative importance or order. Although preferred embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can combine, change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. An air conditioning device, comprising:First refrigerant circulation loop;Second refrigerant circulation loop;The first refrigerant circulation loop and the second refrigerant circulation loop are configured to circulate the refrigerant.The first refrigerant circulation loop includes:A first condenser is configured to exchange heat with the external environment and condense the refrigerant;A first throttling device, configured to expand the refrigerant;A first evaporator is configured to exchange heat with the room to be air-conditioned and to evaporate the refrigerant.A first compressor, configured to compress the refrigerant.The second refrigerant circulation loop includes:A second condenser is configured to exchange heat with the external environment and condense the refrigerant;A second throttling device is configured to expand the refrigerant;A second evaporator is configured to exchange heat with the room to be air-conditioned and is configured to evaporate the refrigerant.A second compressor, configured to compress the refrigerant; and A leak detection unit, configured to determine whether a refrigerant leak has occurred.The leakage detection unit includes:A first temperature sensor is configured to measure the temperature of the first refrigerant circulation loop at the first evaporator.A second temperature sensor, configured to measure the temperature of the second refrigerant circulation loop at the second evaporator; andA control component is configured to receive a first temperature measured by a first temperature sensor and a second temperature measured bya second temperature sensor, and to compare the temperature difference between the first and second temperatures with a temperature reference threshold to generate a signal for determining refrigerant leakage.

2. According to claim 1, the air conditioning device further includes a first pressure sensor and a second pressure sensor, the first pressure sensor being configured to detect a first pressure in the first refrigerant circulation loop, and the second pressure sensor being configured to detect a second pressure in the second refrigerant circulation loop, wherein the control component is configured to receive the first pressure measured by the first pressure sensor and the second pressure measured by the second pressure sensor, and to compare the pressure difference between the first pressure and the second pressure with a pressure reference threshold to generate a signal for determining the refrigerant leakage condition.

3. The air conditioning device according to claim 1, wherein the controlcomponent is configured to generate an alarm signal when the temperature difference exceeds the temperature reference threshold.

4. The air conditioning device according to claim 2, wherein the controlcomponent is configured to generate an alarm signal when the pressure difference exceeds a pressure reference threshold.

5. The air conditioning device according to claim 1, wherein the leakdetection unit further comprises an additional first temperature sensor and an additional second temperature sensor, the additional first temperature sensor being configured to measure the temperature of the first refrigerant circulation loop at the first condenser, and the additional second temperature sensor being configured to measure the temperature of the second refrigerantcirculation loop at the second condenser.

6. The air conditioning device of claim 5, wherein the controlcomponent is configured to receive the temperature measured by the additional first temperature sensor and the temperature measured by the additional second temperature sensor, and compare the difference between them with a second temperature threshold to determine the amount of refrigerant leakage.

7. The air conditioning device according to claim 5, wherein theadditional first temperature sensor is further configured to measure the exhaust temperature of the first refrigerant circulation loop, and the additional second temperature sensor is further configured to measure the exhaust temperature of the second refrigerant circulation loop.

8. The air conditioning device of claim 7, wherein the controlcomponent is configured to receive an exhaust temperature measured by the additional first temperature sensor and an exhaust temperature measured by the additional second temperature sensor, and compare the difference between them with a third temperature threshold to determine the refrigerant leakage condition.

9. The air conditioning device according to claim 1, 6 or 7, wherein thetemperature reference threshold is equal to 1OC ~ 15OC , the second temperature reference threshold is equal to 1.0 ~ 10.0C; the third temperature reference threshold is equal to 1.0 ~ 20.0C, and in the cooling mode, the temperature reference threshold, the second temperature reference threshold and the third temperature reference threshold are all less than the temperature reference threshold in the heating mode.

10. The air conditioning device according to claim 4, wherein the pressurereference threshold is equal to 0.01 MPa to 1.0 MPa, and the pressure reference threshold in the cooling mode is less than the pressure reference threshold in the heating mode.

11. The air conditioning equipment according to claim 1, wherein the first throttling device and the second throttling device are electronic expansion valves or capillary tubes.

12. The air conditioning device of claim 1, further comprising a fourway valve connected to the refrigerant circulation loop and operable in a first position to operate the air conditioning device in a cooling mode and in a second position to operate the air conditioning device in a heating mode, wherein the control component is configured to further select the temperature reference threshold and the pressure reference threshold depending on whether the four-way valve is in the first position or the second position.

13. The air conditioning device according to claim 1 or 2, further comprising a solenoid valve configured to close the leaking refrigerant circulation loop when a refrigerant leak is determined to have occurred in the first refrigerant circulation loop or the second refrigerant circulation loop.

14. The air conditioning equipment according to claim 1, further comprising:The memory stores the temperature threshold parameter and the pressure threshold parameter.The control component is connected to the memory and configured to receive the temperature threshold parameter and the pressure threshold parameter from the memory.

15. A method for detecting refrigerant leakage in an air conditioning unit, wherein the air conditioning unit includes a first refrigerant circulation loop and a second refrigerant circulation loop, both the first and second refrigerant circulation loops including a condenser for heat exchange with the external environment, a throttling device, an evaporator, and a compressor for heat exchange with the room to be air-conditioned, wherein the method includes:Temperature parameters of the first refrigerant circulation loop and the second refrigerant loop are measured by a temperature sensor, wherein the temperature parameters represent the temperature of the refrigerant at the evaporator, the condenser, or the compressor discharge point;The control component receives the temperature parameters of the first refrigerant circulation loop and the temperature parameters of the secondrefrigerant circulation loop.The  difference  between  the  temperature  parameters  of the firstrefrigerant circulation loop and the temperature parameters of the secondrefrigerant circulation loop is compared with the temperature referencethreshold.Generates a signal to determine the refrigerant leak status.

16. The method according to claim 1 or 5 further comprises:The pressure parameters of the first refrigerant circulation loop and the second refrigerant circulation loop are measured using pressure sensors;The control component receives the pressure parameters of the first refrigerant circulation loop and the pressure parameters of the second refrigerant circulation loop.The difference between the pressure parameters of the first refrigerant circulation loop and the pressure parameters of the second refrigerant circulation loop is compared with a pressure reference threshold; andGenerates a signal to determine the refrigerant leak status.

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