R32 heat pump system avoiding to warm stop

Abstract

The application provides an R32 heat pump system avoiding warm shutdown, first connecting the bottom guide pipe of the fin heat sink of the heat pump system to the gas-liquid separator, and providing an exhaust electronic expansion valve on the guide pipe, then detecting the exhaust temperature T of the heat pump system, the compressor frequency Y and the outlet water temperature T2, when the first preset condition is met, entering the exhaust electronic expansion valve control logic, then detecting the exhaust temperature T, the compressor frequency Y and the outlet water temperature T2 in real time, if any one of the second, third and fourth preset conditions is met, adjusting the opening of the exhaust electronic expansion valve according to the corresponding logic control method, sucking the condensate at the bottom of the fin to the gas-liquid separator, then inputting the excess condensate into the compressor through the gas-liquid separator, realizing the temperature control of the compressor, helping the condensation cycle, and solving the problem of R32 heat pump system refrigerant accumulation, low cycle quantity triggering exhaust protection and warm shutdown.

Description

Technical Field

[0001] This invention relates to the field of air conditioning heat pump systems, and in particular to an R32 heat pump system that avoids shutdown when the temperature reaches a certain level. Background Technology

[0002] The existing air conditioning heat pump systems have diverse fin designs. In ultra-low temperature environments, the heat exchange capacity of the evaporator in the heat pump system is poor. In addition, due to the influence of the fin structure, a lot of refrigerant will accumulate at the bottom of the fins. At this time, the entire heat pump system is still on the verge of shutting down due to low temperature. When the ambient temperature is too low, the system cannot complete the heat exchange, and the refrigerant cannot flow and circulate. This results in the entire system being short of refrigerant and operating at low frequency. The circulation volume of the air conditioning heat pump system is greatly reduced. In addition, the system's exhaust volume is also relatively high. At this time, there is no refrigerant to carry away heat from the compressor, so the exhaust volume will rise rapidly and easily trigger the exhaust protection. Summary of the Invention

[0003] Based on the above problems, this invention provides an R32 heat pump system that avoids shutdown at the set temperature. At the same time, it improves the structure and logic control of the existing R32 heat pump system, so that it can solve the problem of low refrigerant accumulation circulation triggering exhaust protection in the R32 heat pump system.

[0004] This invention is achieved through the following technical solution:

[0005] On one hand, this invention provides an R32 heat pump system that avoids shutdown at high temperature, comprising a finned heat exchanger, a four-way valve, a compressor, a gas-liquid separator, a shell-and-tube heat exchanger, a one-way valve assembly, an electronic expansion valve, a three-way valve, a plate heat exchanger, and a controller electrically and / or sensorically connected to the finned heat exchanger, four-way valve, compressor, gas-liquid separator, shell-and-tube heat exchanger, one-way valve assembly, electronic expansion valve, three-way valve, and plate heat exchanger, characterized in that:

[0006] The bottom lead pipe of the finned radiator of the heat pump system is connected to the gas-liquid separator, and the lead pipe is equipped with an exhaust electronic expansion valve. The exhaust electronic expansion valve is electrically connected to the controller and / or sensor-connected. The controller controls the opening and closing of the exhaust electronic expansion valve according to preset conditions.

[0007] With the above settings, when the controller obtains the operating status of the heat pump system and the operating status meets the preset conditions, the controller opens the exhaust electronic expansion valve, draws liquid from the bottom of the finned heat exchanger into the gas-liquid separator, and enters the compressor through the exhaust electronic expansion valve and the gas-liquid separator to realize the compressor's reduced exhaust, thus avoiding the heat pump system from shutting down when it reaches the set temperature.

[0008] Furthermore, the controller controls the opening and closing of the exhaust electronic expansion valve, and its specific adjustment methods include:

[0009] Get the exhaust temperature T, compressor frequency Y and outlet water temperature T2. When the exhaust temperature and compressor frequency simultaneously meet the first preset condition, enter the exhaust electronic expansion valve control logic.

[0010] Real-time monitoring of the heat pump system's exhaust temperature T, compressor frequency Y, and outlet water temperature T2; adjustment of the exhaust electronic expansion valve opening N based on the real-time monitoring values;

[0011] If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the second preset condition; the opening N of the exhaust electronic expansion valve is adjusted to 50% N. max ;

[0012] If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the third preset condition; the opening N of the exhaust electronic expansion valve is adjusted to 80% N. max ;

[0013] If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the fourth preset condition; the opening degree N of the exhaust electronic expansion valve is adjusted to N. max ;where N max This is the maximum opening degree of the exhaust electronic expansion valve.

[0014] Furthermore, before adjusting the opening degree N of the exhaust electronic expansion valve based on the real-time detection value, the controller determines whether to adjust the opening degree of the exhaust electronic expansion valve by:

[0015] Real-time monitoring is conducted for a preset time T1. Within the preset time T1, if the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system all meet any one of the preset first, second, or third preset conditions, the opening degree N of the exhaust electronic expansion valve will be adjusted accordingly.

[0016] Furthermore, after adjusting the opening of the exhaust electronic expansion valve, the controller exits the exhaust electronic expansion valve control logic using the following method:

[0017] The exhaust temperature T of the heat pump system is monitored in real time. If the exhaust electronic expansion valve is lower than the preset temperature stop temperature after it is opened, the exhaust electronic expansion valve is closed and the exhaust electronic expansion valve control logic is exited.

[0018] Furthermore, the second preset condition in the controller is that the exhaust temperature of the heat pump system is T > 100℃ and the compressor frequency is 40HZ ≥ Y > 35HZ, and the outlet water temperature is T2 ≥ 50℃.

[0019] Furthermore, the third preset condition in the controller is that the exhaust temperature of the heat pump system is T > 100℃ and the compressor frequency is 35HZ ≥ Y > 25HZ, and the outlet water temperature is T2 ≥ 50℃.

[0020] Furthermore, the fourth preset condition in the controller is that the exhaust temperature of the heat pump system is T > 100℃ and the compressor frequency is 25HZ ≥ Y > 20HZ, and the outlet water temperature is T2 ≥ 50℃.

[0021] In summary, the present invention provides a control method and device for preventing temperature-limited shutdown in an R32 heat pump system. By improving the existing R32 system and combining it with a specific logic control method, the opening degree of the exhaust electronic expansion valve is correlated with the frequency of the heat pump system. The opening degree of the exhaust electronic expansion valve is adjusted in real time to precisely control the exhaust temperature of the compressor. This solves the problem of condensation buildup at the bottom of the finned heat exchanger and insufficient circulation, which may cause the heat pump system to shut down at the temperature limit.

[0022] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0023] Figure 1 A structural block diagram of a heat pump system provided by the present invention;

[0024] Figure 2 The flowchart shows a logic control method for an R32 heat pump system that avoids shutdown at a certain temperature, as provided by the present invention. Detailed Implementation

[0025] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, unless otherwise stated, “a plurality” means two or more; and the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0026] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only for distinction and not to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] When refrigerant accumulates at the bottom of the fins in a heat pump system, resulting in low frequency and small circulation volume, the heat in the compressor cannot be carried away. At this time, the water temperature in the system's water circulation is still high, causing the system to easily exceed the exhaust over-temperature protection value. Simply controlling the return liquid electronic expansion valve is insufficient to reduce exhaust volume because the circulation volume is inadequate. Furthermore, it's impossible to draw liquid from the enthalpy-increasing side to lower the exhaust temperature. Enthalpy increase is a physical phenomenon; as pressure increases, temperature also increases. Since the enthalpy-increasing side is usually the high-pressure side, the system cannot spontaneously draw liquid from the enthalpy-increasing side to the relatively low-pressure side. Therefore, when no refrigerant carries away heat from the compressor, the overall reliability of the air conditioning heat pump system is affected, and the compressor's lubricating oil is more prone to carbonization under high-temperature exhaust conditions.

[0028] Based on the above description, and referring to Figure 1 , Figure 1 The present invention provides a structural block diagram of a heat pump system. The heat pump system used in the present invention includes a finned heat exchanger, a four-way valve, a compressor, a gas-liquid separator, a shell-and-tube heat exchanger, a one-way valve assembly, an electronic expansion valve, a three-way valve, a plate heat exchanger, and a controller (not shown) that is electrically connected or / and sensor-connected to the finned heat exchanger, the four-way valve, the compressor, the gas-liquid separator, the shell-and-tube heat exchanger, the one-way valve assembly, the electronic expansion valve, the three-way valve, and the plate heat exchanger.

[0029] In the operation of an R32 heat pump system, the following adjustment is made: First, the high-temperature exhaust gas from the compressor passes through the condenser and exchanges heat with water to condense into medium-temperature, medium-pressure liquid refrigerant. Then, it goes to the heat exchanger. The enthalpy-increasing circuit takes a portion of the liquid refrigerant and throttles it to exchange heat with the refrigerant in the heat exchanger for evaporation. This evaporated gas has a lower temperature and goes to the compressor to reduce the exhaust gas (the amount of liquid taken is proportional to the frequency). As the heat pump system continues to run, the water temperature will approach the set shutdown water temperature. At this point, less heating capacity is needed, so the frequency will be reduced to slowly heat to the target water temperature. As the frequency decreases, the amount of liquid taken also decreases until it is insufficient to reduce the exhaust gas. As the frequency decreases, the exhaust gas temperature will increase, eventually rising to 115°C and triggering an over-temperature fault.

[0030] To address the aforementioned issues, this invention first connects the bottom lead pipe of the finned heat exchanger to the gas-liquid separator and equips the pipe with an exhaust electronic expansion valve, which is controlled by a controller. Based on this improvement, when the controller obtains the operating status of the heat pump system, and when the operating status meets the condition of the compressor frequency decreasing to 40Hz and the exhaust temperature ≥100℃, the controller opens the exhaust electronic expansion valve, drawing additional liquid from the bottom of the finned heat exchanger into the gas-liquid separator. After passing through the exhaust electronic expansion valve and the gas-liquid separator, the liquid enters the compressor, achieving reduced exhaust pressure and preventing the heat pump system from shutting down at the set temperature. However, if the exhaust electronic expansion valve opens too wide at once, it may draw too much liquid, and prolonged exposure to excessive liquid refrigerant in the compressor could cause liquid slugging and damage. Therefore, a more precise control method is needed to complement this design.

[0031] To address the aforementioned problems, the inventors have also provided a control method for R32 heat pump systems to avoid shutdown at operating temperature. This method solves the problems of low refrigerant circulation triggering exhaust protection and excessive liquid draw damaging the compressor in R32 heat pump systems. Please refer to [link to relevant documentation]. Figure 2 Figure 1 is a flowchart of a control method for an R32 heat pump system to avoid shutdown at high temperature, provided by the present invention. The controller completes the execution flow of the control method, which specifically includes the following steps:

[0032] S10: Obtain the exhaust temperature T, compressor frequency Y, and outlet water temperature T2. When the exhaust temperature and compressor frequency simultaneously meet the first preset condition, enter the exhaust electronic expansion valve control logic.

[0033] Exhaust temperature refers to the temperature at which the refrigerant is discharged from the air conditioning compressor. It is usually measured on the compressor exhaust pipe. The outlet water temperature of the air conditioning system refers to the temperature at which cooling water or hot water flows out of the air conditioning heat pump system. In this invention, for the R32 heat pump system, the inventor sets the first preset condition as follows: exhaust temperature T≥100℃ and compressor frequency Y≤40HZ.

[0034] S20: Real-time monitoring of the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system; adjusting the opening degree N of the exhaust electronic expansion valve based on the real-time monitoring values.

[0035] After entering the exhaust electronic expansion valve control logic, the heat pump system is already on the verge of shutting down due to reaching the temperature. It is necessary to monitor the operating status of the heat pump system in real time to adjust the system. However, the condensate retrieved by the original heat pump system's return electronic expansion valve cannot meet the requirement of reducing exhaust. At this time, it is necessary to open the exhaust electronic expansion valve to assist the gas-liquid separator in taking liquid from the bottom of the finned heat exchanger based on the operating status of the heat pump system. Then, the gas-liquid separator directly introduces the condensate into the compressor to assist in cooling and reduce exhaust.

[0036] S31: If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the second preset condition; the opening N of the exhaust electronic expansion valve is adjusted to 50% N. max .

[0037] In the R32 heat pump system provided by this invention, the second preset condition is that the exhaust temperature of the heat pump system T > 100℃ and the compressor frequency 40Hz ≥ Y > 35Hz, and the outlet water temperature T2 ≥ 50℃. When the second preset condition is met, the opening degree of the exhaust electronic expansion valve is adjusted to 50% of the maximum opening degree.

[0038] S32: If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the third preset condition; the opening N of the exhaust electronic expansion valve is adjusted to 80% N. max .

[0039] In the R32 heat pump system provided by this invention, the third preset condition is that the exhaust temperature T of the heat pump system is greater than 100℃ and the compressor frequency is 30Hz ≥ Y > 25Hz, and the outlet water temperature T2 is greater than 50℃. When the third preset condition is met, the opening of the exhaust electronic expansion valve is adjusted to 80% of its maximum opening. Since the compressor frequency changes rapidly within a certain range and usually does not fall into the corresponding range, in the heat pump system of this invention, the second and third preset conditions ignore the 35Hz-30Hz range. When the compressor frequency reaches 25Hz-30Hz, the opening of the electronic expansion valve is close to its maximum.

[0040] S33: If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the fourth preset condition; the opening degree N of the exhaust electronic expansion valve is adjusted to N. max .

[0041] In the R32 heat pump system provided by this invention, the fourth preset condition is that the exhaust temperature of the heat pump system T > 100℃ and the compressor frequency 25Hz ≥ Y > 20Hz, and the outlet water temperature T2 ≥ 50℃. When the fourth preset condition is met, the opening degree of the exhaust electronic expansion valve is adjusted to the maximum opening degree.

[0042] By setting multiple preset conditions, the opening of the electronic expansion valve is adjusted systematically, avoiding sudden excessive opening. In cases of prolonged accumulation of excessive liquid refrigerant, a sudden wide opening of the electronic expansion valve could lead to liquid slugging and damage to the compressor. Conversely, appropriate liquid removal ensures that the refrigerant entering the compressor evaporates instantly, preventing liquid slugging and simultaneously providing a cooling effect.

[0043] In another embodiment, after entering the exhaust electronic expansion valve control logic, the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system are monitored in real time for a preset time. If any one of the preset first, second, or third preset conditions is met within the preset time, the opening degree N of the exhaust electronic expansion valve is adjusted accordingly. This step is executed by a certain time subunit.

[0044] Because the heat pump system may be adjusted by other frequency increase or decrease operations during operation, it is necessary to detect a continuous period of time to accurately determine whether the heat pump system can exit the temperature shutdown state according to the frequency decrease operation. In the R32 heat pump system provided by this invention, the preset time is 1 minute.

[0045] In another embodiment, after adjusting the opening of the exhaust electronic expansion valve, step 40 is further included:

[0046] The exhaust temperature T of the heat pump system is monitored in real time. If the exhaust electronic expansion valve is lower than the preset stop temperature after opening, the exhaust electronic expansion valve is closed, and the exhaust electronic expansion valve control logic is exited. Step 40 is executed by the control logic exit unit 40.

[0047] In summary, the logic control method of this invention adjusts the operation of an R32 heat pump system as follows: First, high-temperature exhaust gas from the compressor passes through the condenser and exchanges heat with water to condense into medium-temperature, medium-pressure liquid refrigerant. Then, it goes to the heat exchanger. The enthalpy-increasing circuit takes a portion of the liquid refrigerant and throttles it to exchange heat with the refrigerant in the heat exchanger for evaporation. This evaporated gas, being at a lower temperature, goes to the compressor to reduce exhaust gas (the amount of liquid taken is proportional to the frequency). As the heat pump system continues to operate, the water temperature approaches the set shutdown temperature. At this point, less heating capacity is needed, so the frequency is reduced to slowly heat the water to the target temperature. Due to the reduced frequency, the amount of liquid taken also decreases until it is insufficient to reduce exhaust gas. As the frequency decreases, the exhaust gas temperature rises, eventually reaching 115°C and triggering an over-temperature fault. Therefore, when the frequency drops to 40Hz and the exhaust gas temperature is ≥100°C, the exhaust electronic expansion valve control logic is activated. The system continuously monitors the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system for one minute. If any of the following preset conditions are met, the corresponding logic control steps are executed: If the second preset condition is met, the opening of the exhaust electronic expansion valve is adjusted to 50% of its maximum opening; if the third preset condition is met, the opening is adjusted to 80% of its maximum opening; and if the fourth preset condition is met, the opening is adjusted to its maximum opening. At this time, the condensate accumulated at the bottom of the finned heat exchanger is drawn back through a pipe to the gas-liquid separator. The gas-liquid separator then delivers excess condensate to the compressor to help cool it. The exhaust temperature is then continuously monitored. If the exhaust temperature is less than 90°C, the exhaust electronic expansion valve control logic is exited, and the R32 heat pump system operates normally. This invention improves the existing R32 system and combines it with a specific logic control method to correlate the opening degree of the exhaust electronic expansion valve with the frequency of the heat pump system, thereby adjusting the opening degree of the exhaust electronic expansion valve in real time and accurately controlling the exhaust temperature of the compressor. This solves the problem of condensation buildup at the bottom of the finned heat exchanger and insufficient circulation, which may cause the heat pump system to shut down when it reaches the set temperature.

[0048] Based on the same inventive concept described above, the present invention also provides an electronic device, which may be a server, a desktop computing device, or a mobile computing device (e.g., a laptop computing device, a handheld computing device, a tablet computer, a netbook, etc.). This device includes one or more processors and a memory, wherein the processor is used to execute a program to implement the aforementioned control method for preventing temperature-induced shutdown of an R32 heat pump system; the memory is used to store a computer program executable by the processor.

[0049] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. An R32 heat pump system that avoids shutdown at high temperature, comprising a finned heat exchanger, a four-way valve, a compressor, a gas-liquid separator, a shell-and-tube heat exchanger, a one-way valve assembly, an electronic expansion valve, a three-way valve, a plate heat exchanger, and a controller electrically and / or sensorically connected to the finned heat exchanger, the four-way valve, the compressor, the gas-liquid separator, the shell-and-tube heat exchanger, the one-way valve assembly, the electronic expansion valve, the three-way valve, and the plate heat exchanger, wherein the outlet of the compressor is connected to the inlet of the four-way valve, the outlet of the four-way valve is connected to the shell-and-tube heat exchanger, and the outlet of the shell-and-tube heat exchanger is connected to the inlet of the one-way valve assembly. The one-way valve assembly has its outlet connected to the first inlet of the plate heat exchanger, the first outlet of the plate heat exchanger connected to the inlet of the three-way valve, the first outlet of the three-way valve connected to the electronic expansion valve, the outlet of the electronic expansion valve connected to the one-way valve assembly, the outlet of the one-way valve assembly connected to the inlet of the finned heat exchanger, and the outlet of the finned heat exchanger connected to the inlet of the gas-liquid separator; the second outlet of the three-way valve connected to the second inlet of the plate heat exchanger, and the second outlet of the plate heat exchanger connected to the enthalpy-increasing port of the compressor, thereby increasing the enthalpy of the compressor. The characteristic feature is that: The finned radiator of the heat pump system is an evaporator. A lead pipe is provided at the bottom of the finned radiator, and an additional inlet is provided on the gas-liquid separator for connecting the liquid refrigerant at the bottom of the finned radiator to the gas-liquid separator via the lead pipe. An exhaust electronic expansion valve is equipped on the lead pipe. The exhaust electronic expansion valve is electrically connected to the controller and / or sensor-connected. The controller controls the opening and closing of the exhaust electronic expansion valve according to preset conditions, including: The discharge temperature of the compressor is detected. When the temperature exceeds a preset threshold, the following steps are performed: Get the exhaust temperature T, compressor frequency Y and outlet water temperature T2. When the exhaust temperature and compressor frequency simultaneously meet the first preset condition, enter the exhaust electronic expansion valve control logic. Real-time monitoring of the heat pump system's exhaust temperature T, compressor frequency Y, and outlet water temperature T2; adjustment of the exhaust electronic expansion valve opening N based on the real-time monitoring values; If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the second preset condition; the opening N of the exhaust electronic expansion valve is adjusted to... ; If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the third preset condition; the opening N of the exhaust electronic expansion valve is adjusted to... ; If the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system meet the fourth preset condition; the opening N of the exhaust electronic expansion valve is adjusted to... ;in The maximum opening degree of the exhaust electronic expansion valve is defined as follows: the lower the compressor frequency Y, the larger the opening degree of the exhaust electronic expansion valve.

2. The R32 heat pump system for avoiding shutdown at temperature as described in claim 1, characterized in that, Before adjusting the opening degree N of the exhaust electronic expansion valve based on the real-time detection value, the controller determines whether to adjust the opening degree of the exhaust electronic expansion valve by: Real-time monitoring is conducted for a preset time T1. Within the preset time T1, if the exhaust temperature T, compressor frequency Y, and outlet water temperature T2 of the heat pump system all meet any one of the preset second, third, or fourth preset conditions, the opening degree N of the exhaust electronic expansion valve will be adjusted accordingly.

3. An R32 heat pump system for avoiding shutdown at temperature as described in claim 2, characterized in that, After adjusting the opening of the exhaust electronic expansion valve, the controller exits the exhaust electronic expansion valve control logic using the following method: The exhaust temperature T of the heat pump system is monitored in real time. If the exhaust electronic expansion valve is lower than the preset temperature stop temperature after it is opened, the exhaust electronic expansion valve is closed and the exhaust electronic expansion valve control logic is exited.

4. An R32 heat pump system that avoids shutdown at temperature according to any one of claims 1-3, characterized in that: The second preset condition in the controller is that the exhaust temperature of the heat pump system is T > 100℃ and the compressor frequency is 40HZ ≥ Y > 35HZ, and the outlet water temperature is T2 ≥ 50℃.

5. An R32 heat pump system that avoids shutdown at temperature according to any one of claims 1-3, characterized in that: The third preset condition in the controller is that the exhaust temperature of the heat pump system is T > 100℃ and the compressor frequency is 35HZ ≥ Y > 25HZ, and the outlet water temperature is T2 ≥ 50℃.

6. An R32 heat pump system that avoids shutdown at temperature according to any one of claims 1-3, characterized in that: The fourth preset condition in the controller is that the exhaust temperature of the heat pump system is T > 100℃ and the compressor frequency is 25HZ ≥ Y > 20HZ, and the outlet water temperature is T2 ≥ 50℃.

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