Four-way valve reversing control method and heat pump system

Abstract

The present invention belongs to the technical field of heat pump systems and discloses a four-way valve reversing control method and a heat pump system. The four-way valve reversing control method first detects whether hot water is flowing through the hot water pump of the heat pump system before reversing the four-way valve body. Specifically, the hot water flow is detected by the temperature difference between the exhaust temperature T1 and the casing liquid pipe temperature T2, thereby preventing the hot water pump from idling due to water shortage. When performing reversing control of the four-way valve body, the temperature difference between the exhaust temperature T1 and the casing liquid pipe temperature T2 is used for judgment, preventing the four-way valve body from switching in a liquid refrigerant state, preventing the four-way valve body from experiencing liquid hammering, resulting in switching jams and poor switching, and avoiding malfunctions of the heat pump system. The four-way valve reversing control method can ensure the reliable operation of the four-way valve body when the heat pump system switches operating modes and the four-way valve body switches flow directions, thereby ensuring the safe operation of the heat pump system and reducing the occurrence of malfunctions.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and in particular to a four-way valve reversing control method and a heat pump system. Background Art

[0002] The four-way valve is the most commonly used fluid control element in heat pump systems. Its operation is controlled by electrical signals, primarily through the relative movement of the valve core and valve body to change the direction of the fluid in the system, thereby switching the system between cooling and heating modes and achieving defrost. In a heat pump system, the four-way valve is connected to the compressor exhaust pipe. When the system is operating in normal cooling or heating mode, the refrigerant discharged from the compressor and passing through the four-way valve is high-temperature, high-pressure gaseous refrigerant. As a critical functional component in a heat pump, a malfunction of the four-way valve will prevent the system from switching between cooling and heating modes.

[0003] In the prior art, when the heat pump system is operating in heating or hot water mode, the flow direction of the four-way valve needs to be switched. When the heat pump unit is started, the refrigerant exchanges heat with the water in the casing and condenses, causing the refrigerant flowing out of the casing heat exchanger to condense into liquid. If the liquid refrigerant is switched through the four-way valve, the four-way valve may be damaged or stuck, thereby causing the four-way valve switching to be stuck and the heat pump unit to malfunction. In addition, if there is no water in the hot water tank, the continuous operation of the water pump will cause the water pump to idle and be damaged, which may also cause the heat pump system unit to malfunction.

[0004] Therefore, there is an urgent need to provide a novel four-way valve reversing control method and a heat pump system to solve the above-mentioned technical problems in the prior art. Summary of the Invention

[0005] One object of the present invention is to provide a four-way valve reversing control method, which can ensure the reliable operation of the four-way valve body when the heat pump system switches the working mode and the four-way valve body switches the flow direction, thereby ensuring the safe operation of the heat pump system and reducing the occurrence of faults.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The four-way valve reversing control method is applied to a heat pump system, which includes a compressor, a fin heat exchanger, a plate heat exchanger, an expansion valve, a four-way valve body, a hot water tank, a shell and tube heat exchanger and a hot water pump. The compression outlet of the compressor is respectively connected to the medium inlet of the hot water tank and the shell inlet of the shell and tube heat exchanger. The medium outlet of the hot water tank and the shell and tube outlet of the shell and tube heat exchanger are both connected to port A of the four-way valve body. Port B of the four-way valve body is connected to one end of the fin heat exchanger. The other end of the fin heat exchanger is connected to one end of the expansion valve. The other end of the expansion valve is connected to the first port of the plate heat exchanger. The second port of the plate heat exchanger is connected to port C of the four-way valve body. Port D of the four-way valve body is connected to the compression inlet of the compressor. The hot water pump is arranged at the medium outlet of the hot water tank to form a circulation system. There is a heat exchange medium in the circulation system. The four-way valve reversing control method includes the following steps: S1, detecting the exhaust temperature T1 of the compressor and the casing liquid pipe temperature T2 of the casing heat exchanger. If T1-T2≤10℃, the hot water pump is turned off; S2, the hot water pump is restarted, and the process returns to step S1; S3, judging the working mode of the heat pump system: if it is a heating mode, step S41 is executed; if it is a hot water mode, step S42 is executed; S41, the air conditioner indoor unit connected to the heat pump system is turned on, the expansion valve is opened at a preset opening, and the compressor is frequency-increased to a preset frequency. If T1-T2≤10℃, the four-way valve body is opened, and then the frequency of the compressor and the opening of the expansion valve are adjusted; S42, the expansion valve is opened at a preset opening, and the compressor is frequency-increased to a preset frequency. If T1-T2≤10℃, the four-way valve body is opened, and then the opening of the expansion valve is adjusted and the hot water pump is turned on. Finally, the frequency of the compressor is adjusted.

[0008] Optionally, step S1 is performed 30 seconds after the hot water pump is started, and the hot water pump is turned off after the state of T1-T2≤10°C lasts for 10 seconds.

[0009] Optionally, in step S1, when the hot water pump is turned off, a hot water flow failure is displayed on a display, and 50 seconds after the hot water pump is turned off, the process returns to step S1.

[0010] Optionally, if the display continuously shows a hot water flow failure three or more times within one hour, the heat pump system is shut down and restarted after one hour.

[0011] Optionally, in step S41 and step S42, the four-way valve body is opened after the fan is turned on for 3 seconds.

[0012] Optionally, in step S41 and step S42, the preset opening of the expansion valve is 400 steps.

[0013] Optionally, in step S41 and step S42, the preset frequency of the compressor is 40 Hz.

[0014] Optionally, in step S41, the air-conditioning return pipe of the above-mentioned air-conditioning indoor unit is connected to the third port of the above-mentioned plate heat exchanger, and the above-mentioned air-conditioning return pipe is provided with an air-conditioning pump. When the above-mentioned air-conditioning indoor unit is turned on, the above-mentioned air-conditioning pump is turned on synchronously, and the above-mentioned expansion valve is opened 50 seconds after the above-mentioned air-conditioning pump is turned on.

[0015] Optionally, in step S42, the frequency of the compressor is adjusted after the hot water pump is turned on for 50 seconds.

[0016] Another object of the present invention is to provide a heat pump system, which uses the four-way valve reversing control method described in any of the above solutions to switch the flow direction of the four-way valve body.

[0017] Beneficial effects:

[0018] The four-way valve reversing control method of the present invention first detects whether hot water is flowing through the hot water pump of the heat pump system before activating the reversing of the four-way valve body. Specifically, the hot water flow is detected by the temperature difference between the exhaust temperature T1 and the casing liquid pipe temperature T2, thereby preventing the hot water pump from idling due to water shortage and causing damage to the hot water pump, thereby improving the operational reliability of the heat pump system. When performing the reversing control of the four-way valve body, the temperature difference between the exhaust temperature T1 and the casing liquid pipe temperature T2 is used for judgment to prevent the four-way valve body from switching in the liquid refrigerant state, prevent the four-way valve body from experiencing liquid hammer, resulting in switching jams and poor switching, and avoid malfunctions of the heat pump system. The four-way valve reversing control method can ensure the reliable operation of the four-way valve body when the heat pump system switches operating modes and the four-way valve body switches flow directions, thereby ensuring the safe operation of the heat pump system and reducing the occurrence of malfunctions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of a heat pump system provided by a specific embodiment of the present invention.

[0020] In the picture:

[0021] 100. Compressor; 101. First thermometer; 102. Second thermometer; 200. Fin heat exchanger; 300. Expansion valve; 400. Plate heat exchanger; 401. First port; 402. Second port; 403. Third port; 404. Fourth port; 500. Four-way valve body; 501. Port A; 502. Port B; 503. Port C; 504. Port D; 600. Hot water tank; 700. Shell and tube heat exchanger; 701. Third thermometer; 800. Hot water pump; 901. Air conditioning pump; 902. Water flow switch. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0023] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0024] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0025] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0026] Please refer to Figure 1In this embodiment, a heat pump system is first provided, which includes a compressor 100, a fin heat exchanger 200, a plate heat exchanger 400, an expansion valve 300, a four-way valve body 500, a hot water tank 600, a shell and tube heat exchanger 700 and a hot water pump 800. The compression outlet of the compressor 100 is respectively connected to the medium inlet of the hot water tank 600 and the shell inlet of the shell and tube heat exchanger 700. The medium outlet of the hot water tank 600 and the shell outlet of the shell and tube heat exchanger 700 are both connected to the A port 501 of the four-way valve body 500. The B port of the four-way valve body 500 is connected to the B port of the four-way valve body 500. The port 502 is connected to one end of the above-mentioned fin heat exchanger 200, the other end of the above-mentioned fin heat exchanger 200 is connected to one end of the above-mentioned expansion valve 300, the other end of the above-mentioned expansion valve 300 is connected to the first port 401 of the above-mentioned plate heat exchanger 400, the second port 402 of the above-mentioned plate heat exchanger 400 is connected to the C port 503 of the above-mentioned four-way valve body 500, and the D port 504 of the above-mentioned four-way valve body 500 is connected to the compression inlet of the above-mentioned compressor 100. The above-mentioned hot water pump 800 is arranged at the medium outlet of the above-mentioned hot water tank 600 to form a circulation system, and the above-mentioned circulation system has a heat exchange medium.

[0027] The heat pump system described above utilizes the four-way valve reversing control method of this embodiment, as described below. This heat pump system not only recovers the sensible heat and a portion of the latent heat from the exhaust of compressor 100 to produce domestic hot water, but also implements multiple functional modes, enabling hot water production in both summer and winter, while also meeting both cooling and heating needs. Furthermore, the use of the four-way valve reversing control method of this embodiment ensures the reliable operation of the four-way valve body 500 when the heat pump system switches operating modes and the four-way valve body 500 switches flow direction, thereby ensuring safe operation of the heat pump system and reducing the risk of malfunctions.

[0028] Furthermore, a first thermometer 101 is provided at the compression outlet of the compressor 100 for detecting the exhaust temperature T1 of the compressor 100, and a second thermometer 102 is provided at the compression inlet of the compressor 100 for detecting the intake temperature of the compressor 100; a third thermometer 701 is provided between the casing outlet of the casing heat exchanger 700 and the A port 501 of the above-mentioned four-way valve body 500 for detecting the casing liquid pipe temperature T2 of the casing heat exchanger 700.

[0029] Specifically, the four-way valve reversing control method applied to the above-mentioned heat pump system includes the following steps: S1, detecting the exhaust temperature T1 of the above-mentioned compressor 100 and the casing liquid pipe temperature T2 of the above-mentioned casing heat exchanger 700, and if T1-T2≤10°C, turning off the above-mentioned hot water pump 800; S2, restarting the above-mentioned hot water pump 800, and returning to step S1; S3, judging the working mode of the above-mentioned heat pump system: if it is heating mode, executing step S41; if it is hot water mode, executing step S42; S41, turning on the air conditioner indoor unit connected to the heat pump system, The expansion valve 300 is opened at a preset opening, and the compressor 100 is frequency-increased to a preset frequency. If T1-T2≤10°C, the four-way valve body 500 is opened, and then the frequency of the compressor 100 and the opening of the expansion valve 300 are adjusted; S42, the expansion valve 300 is opened at a preset opening, and the compressor 100 is frequency-increased to a preset frequency. If T1-T2≤10°C, the four-way valve body 500 is opened, and then the opening of the expansion valve 300 is adjusted and the hot water pump 800 is opened, and finally the frequency of the compressor 100 is adjusted.

[0030] The four-way valve reversing control method of this embodiment first detects whether hot water is flowing through the hot water pump 800 of the heat pump system before activating the reversing of the four-way valve body 500. Specifically, the hot water flow is detected by measuring the temperature difference between the exhaust temperature T1 and the casing liquid pipe temperature T2. This prevents the hot water pump 800 from idling due to water shortage, which could damage the hot water pump 800 and improve the operational reliability of the heat pump system. When performing the reversing control of the four-way valve body 500, the temperature difference between the exhaust temperature T1 and the casing liquid pipe temperature T2 is used to determine whether the four-way valve body 500 is switched in the liquid refrigerant state. This prevents the four-way valve body 500 from experiencing liquid hammer, which could cause switching jams and poor switching, thereby avoiding malfunctions of the heat pump system. This four-way valve reversing control method can ensure the reliable operation of the four-way valve body 500 when the heat pump system switches operating modes and the four-way valve body 500 switches flow directions, thereby ensuring the safe operation of the heat pump system and reducing the occurrence of malfunctions.

[0031] Specifically, 30 seconds after the hot water pump 800 is started, step S1 is executed again, and after the state of T1-T2≤10°C continues for 10 seconds, the hot water pump 800 is turned off. This configuration allows the hot water pump 800 to be detected for a period of time before being tested for the presence of hot water, thus avoiding false triggering of a fault caused by a temporary lack of water in the system at the moment of starting the system. Furthermore, the hot water pump 800 is shut down only after it has been continuously detected that there is no hot water for 10 seconds, thus avoiding false triggering of faults caused by occasional measurement errors. This improves the accuracy and reliability of the four-way valve reversing control method for detecting water flow in the hot water pump 800.

[0032] Optionally, in step S1, when the hot water pump 800 is turned off, a hot water flow failure is displayed on a display, and after the hot water pump 800 has been turned off for 50 seconds, the process returns to step S1. Displaying the hot water flow failure on the display can alert users to the water flow failure, allowing timely inspection and maintenance. Furthermore, the hot water pump 800 is automatically turned on again after being turned off for 50 seconds, automatically resuming the operation of the heat pump system, thereby performing automatic system recovery. This avoids prolonged operation of the heat pump system due to occasional minor faults, and eliminates the need for lengthy maintenance. If the heat pump system can operate normally after restarting the system, maintenance costs can be reduced.

[0033] In this embodiment, if the display shows a hot water flow failure three or more times within one hour, the heat pump system is shut down and restarted one hour later. If the hot water flow failure is displayed three times within one hour, it indicates that the hot water mode of the heat pump system has failed. At this time, the heat pump system should not be restarted and must be shut down for maintenance and repair.

[0034] Furthermore, in step S41 and step S42, the four-way valve body 500 is opened after the fan is turned on for 3 seconds. Specifically, the four-way valve body 500 can also be opened after the fan is turned on for a preset time such as 4 seconds, 5 seconds, or 6 seconds, which will not be repeated here.

[0035] Optionally, in steps S41 and S42, the preset opening of the expansion valve 300 is 400. If the opening of the expansion valve 300 is too small, insufficient liquid supply will result, reducing refrigeration efficiency and cooling capacity, thereby reducing the cooling effect of the air conditioner. If the opening of the expansion valve 300 is too large, more refrigerant will flow through, causing excessive evaporation of the liquid refrigerant, increasing power consumption of the compressor 100, and causing frost on the compressor 100. Those skilled in the art can select the preset opening of the expansion valve 300 based on their specific needs, and this will not be described in detail here.

[0036] It should be noted that in steps S41 and S42, the preset frequency of the compressor 100 is 40 Hz. 40 Hz is the default frequency of the compressor 100 when the four-way valve body 500 switches the flow direction. At this frequency, the compressor 100 can operate more reliably, improving the safety and reliability of use. This will not be further described here.

[0037] As a preferred embodiment, in step S41, the air conditioning return pipe of the air conditioner is connected to the third port 403 of the plate heat exchanger 400. The air conditioning return pipe is equipped with an air conditioning pump 901. When the air conditioner is turned on, the air conditioning pump 901 is simultaneously turned on, and the expansion valve 300 is opened 50 seconds after the air conditioning pump 901 is turned on. Furthermore, the fourth port 404 of the plate heat exchanger 400 is connected to the air conditioning outlet pipe of the air conditioner. The air conditioning outlet pipe is equipped with a water flow switch 902 to control the connection between the air conditioner and the plate heat exchanger 400. Opening the expansion valve 300 50 seconds after the air conditioning pump 901 is turned on allows the expansion valve 300 to be opened only after the system has stabilized, ensuring continuous and stable heat exchange between the air conditioner and the heat pump system, thereby improving the operational reliability and energy efficiency of the heat pump system.

[0038] Optionally, in step S42, the frequency of the compressor 100 is adjusted 50 seconds after the hot water pump 800 is turned on. Adjusting the frequency of the compressor 100 after the hot water pump 800 has been turned on for a period of time can ensure that hot water continues to flow through the hot water pump 800 of the heat pump system, avoid system failures caused by idling of the hot water pump 800, and avoid damage to the compressor 100 and other components, thereby improving the operational reliability of the system and the service life of the heat pump system.

[0039] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A four-way valve reversing control method, characterized in that: The invention is applied to a heat pump system, wherein the heat pump system comprises a compressor (100), a fin heat exchanger (200), a plate heat exchanger (400), an expansion valve (300), a four-way valve body (500), a hot water tank (600), a shell and tube heat exchanger (700) and a hot water pump (800), wherein the compression outlet of the compressor (100) is respectively connected to the medium inlet of the hot water tank (600) and the shell and tube inlet of the shell and tube heat exchanger (700), the medium outlet of the hot water tank (600) and the shell and tube outlet of the shell and tube heat exchanger (700) are both connected to the A port (501) of the four-way valve body (500), and the B port (502) of the four-way valve body (500) is connected to the fin heat exchanger (200). One end of the heat exchanger (200), the other end of the fin heat exchanger (200) is connected to one end of the expansion valve (300), the other end of the expansion valve (300) is connected to the first port (401) of the plate heat exchanger (400), the second port (402) of the plate heat exchanger (400) is connected to the C port (503) of the four-way valve body (500), the D port (504) of the four-way valve body (500) is connected to the compression inlet of the compressor (100), the hot water pump (800) is arranged at the medium outlet of the hot water tank (600) to form a circulation system, and the circulation system has a heat exchange medium. The four-way valve reversing control method comprises the steps of: S1, detecting the exhaust temperature T1 of the compressor (100) and the casing liquid pipe temperature T2 of the casing heat exchanger (700), and if T1-T2≤10°C, shutting down the hot water pump (800); S2, restarting the hot water pump (800), and returning to step S1; S3, determining the operating mode of the heat pump system: if it is heating mode, executing step S41; if it is hot water mode, executing step S42; S41, turning on the indoor unit of the air conditioner connected to the heat pump system, the expansion valve (300) is opened at a preset opening, the compressor (100) is frequency-increased to a preset frequency, and if T1-T2≤10°C, the four-way valve body (500) is turned on, and then the frequency of the compressor (100) and the opening of the expansion valve (300) are adjusted; S42: The expansion valve (300) is opened at a preset opening, and the compressor (100) is frequency-increased to a preset frequency. If T1-T2≤10°C, the four-way valve body (500) is opened, and then the opening of the expansion valve (300) is adjusted and the hot water pump (800) is turned on. Finally, the frequency of the compressor (100) is adjusted.

2. The four-way valve reversing control method according to claim 1, characterized in that: 30 seconds after the hot water pump (800) is started, step S1 is performed again, and after the state of T1-T2≤10°C continues for 10 seconds, the hot water pump (800) is turned off.

3. The four-way valve reversing control method according to claim 2, characterized in that: In step S1, when the hot water pump (800) is turned off, a hot water flow failure is displayed on the display, and 50 seconds after the hot water pump (800) is turned off, the process returns to step S1.

4. The four-way valve reversing control method according to claim 3, characterized in that: If the display continuously shows hot water flow failure 3 times or more within 1 hour, the heat pump system is shut down and restarted after 1 hour.

5. The four-way valve reversing control method according to claim 1, characterized in that: In step S41 and step S42, the fan is turned on for 3 seconds, and then the four-way valve body (500) is turned on.

6. The four-way valve reversing control method according to claim 5, characterized in that: In step S41 and step S42, the preset opening degree of the expansion valve (300) is 400 steps.

7. The four-way valve reversing control method according to claim 5, characterized in that: In step S41 and step S42, the preset frequency of the compressor (100) is 40 Hz.

8. The four-way valve reversing control method according to claim 5, characterized in that: In step S41, the air-conditioning return water pipe of the air-conditioning indoor unit is connected to the third port (403) of the plate heat exchanger (400), and the air-conditioning return water pipe is provided with an air-conditioning pump (901). When the air-conditioning indoor unit is turned on, the air-conditioning pump (901) is turned on synchronously, and the expansion valve (300) is opened 50 seconds after the air-conditioning pump (901) is turned on.

9. The four-way valve reversing control method according to claim 5, characterized in that: In step S42, after the hot water pump (800) is turned on for 50 seconds, the frequency of the compressor (100) is adjusted.

10. A heat pump system, characterized in that The flow direction of the four-way valve body (500) is switched using the four-way valve reversing control method according to any one of claims 1 to 9.

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