Finned coil pipe temperature determination method and heat pump system

Abstract

According to the method, whether the absolute temperature difference between the temperature of a bottom coil pipe and the temperature of a middle coil pipe of a fin heat exchanger is within a set temperature difference threshold value range or not is compared, the operation mode of the heat pump system and corresponding control logic are combined, and the temperature of the fin coil pipe is determined according to different function scenes. The temperature of the bottom coil or the temperature of the middle coil or the mean value of the two is selected as a control parameter for controlling the refrigerant flow of the heat pump system; according to the double-coil-pipe temperature control scheme, the accuracy of controlling the refrigerant flow and the fan rotating speed based on the coil pipe temperature can be effectively improved, so that the functions of hot water control, refrigeration control, defrosting control, superheat degree control, fan control, overhigh refrigeration coil pipe temperature protection and the like of a heat pump system are more accurate and timely; the stability and reliability of operation of the heat pump system are remarkably improved, and the adaptive capacity of the heat pump system under complex working conditions is enhanced.

Description

Technical Field

[0001] This invention relates to the field of heat pump system control technology, and in particular to a method for determining the temperature of a finned coil and a heat pump system. Background Technology

[0002] Existing heat pump systems typically consist of a compressor, a water-side heat exchanger, an electronic expansion valve, a finned heat exchanger, and a controller.

[0003] The controller operates the system by collecting temperature and pressure information. Among these, the finned coil temperature is a crucial parameter for the heat pump system, affecting defrosting, superheat control, fan control, and overheat protection of the cooling coil. Therefore, ensuring the accuracy of finned coil temperature detection is essential for the stable operation of the heat pump system.

[0004] Currently, heat pump systems use a single temperature sensor fixed to the coil at the bottom flow path of the finned heat exchanger to detect the finned coil temperature. This method of using a single temperature sensor to obtain the finned coil temperature has the following drawbacks:

[0005] 1) The coil temperature detected by a single temperature sensor deviates from the actual condensing or evaporating temperature. Especially in cooling or heating mode, the bottom flow path coil temperature cannot accurately represent the overall coil temperature, resulting in inaccurate control function. 2) When the sensor is fixed to the coil, it is prone to poor insulation or falling off, which affects the stability of the system; 3) When the flow distribution in the finned heat exchanger is uneven, the data deviation at a single detection point is large, which further reduces the reliability of the system control.

[0006] These problems cause heat pump systems to perform poorly in key functions such as defrosting and superheat regulation. Summary of the Invention

[0007] Based on this, the purpose of the present invention is to provide a method for determining the temperature of a finned coil and a heat pump system, which can obtain a stable and reliable finned coil temperature, and make the deviation between the detected finned coil temperature and the actual evaporation temperature or condensation temperature smaller, thereby ensuring the stable operation of the heat pump system.

[0008] A method for determining the temperature of a finned coil, applicable to a heat pump system in which a first temperature sensor is installed on the bottom coil of the finned heat exchanger and a second temperature sensor is installed on the middle coil, includes the following steps: S10: Obtain the operating mode of the heat pump system and the control logic corresponding to the current operating mode; S20: Obtain the temperature at the bottom of the coil. and the temperature in the middle of the coil ; S40: Calculate the bottom temperature of the coil Temperature in the middle of the coil The absolute difference ΔTp is used to determine whether the absolute difference ΔTp is greater than or equal to the absolute difference threshold Δ. : If so, proceed to step S50A; If not, proceed to step S50B; S50A: In the exhaust superheat control logic of cooling mode, As a control coil temperature In other cases, As a control coil temperature ; S50B: In the fan speed control logic or fin temperature overheat protection logic of cooling mode, As a control coil temperature In the fan speed control logic of hot water mode or the fin temperature control logic of defrost mode, As a control coil temperature In other cases, As a control coil temperature ; in, This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The maximum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The minimum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The mean.

[0009] Furthermore, the temperature of the control coil will be controlled. As the evaporation temperature T E At the same time, it also includes S60A: When running in hot water mode, the ambient temperature Ta is obtained; the coil temperature compensation value △T is determined based on the temperature range to which the ambient temperature Ta belongs. R And based on the coil temperature compensation value △T R Temperature control coil The evaporation temperature T was calculated. E .

[0010] Furthermore, a first ambient temperature threshold is adopted. Second ambient temperature threshold The temperature range is divided into three temperature zones, corresponding to three different side coil temperature compensation values, with evaporation temperature T. E The calculation is as follows: If the ambient temperature Ta ≥ the first ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ; If the ambient temperature Ta ≤ the second ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ; If the second ambient temperature threshold <Ambient temperature Ta < First ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ; in, This is the temperature compensation value for the first coil. This is the temperature compensation value for the second coil. The temperature compensation value for the third coil is [value], and the temperature compensation value for the first coil is [value]. >Second coil temperature compensation value Second ambient temperature threshold <First ambient temperature threshold .

[0011] Furthermore, the third coil temperature compensation value satisfy: .

[0012] Furthermore, the temperature of the control coil will be controlled. As the condensation temperature T C At the same time, it also includes S60B: When operating in cooling or defrosting mode, obtain the coil temperature compensation value △T. R ; Based on the coil temperature compensation value △T R Temperature control coil The condensation temperature T was calculated. C : T C = +△T R , Among them, △T R The constant C is set.

[0013] Furthermore, it also includes step S30: Based on the operating mode and the temperature at the bottom of the coil and the temperature in the middle of the coil Determine if the first and second temperature sensors are faulty: If both the first and second temperature sensors are functioning normally, proceed to step S40. If both the first and second temperature sensors malfunction, an alarm will sound and the machine will shut down. If either the first or second temperature sensor is functioning correctly, then use the functioning one.

[0014] Furthermore, in hot water mode, the temperature at the bottom of the coil is determined. and the temperature in the middle of the coil Is it in [ + 1, Within the range of 2]: If none of them are [ + 1, If the temperature is within the range of 2], the first temperature sensor and the second temperature sensor are determined to be faulty, and an alarm is triggered to stop the machine; If only the temperature at the bottom of the coil is available exist[ + 1, If the temperature is within the range of 2], the first temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60; If only the temperature in the middle of the coil is present. exist[ + 1, If the temperature is within the range of 2], the second temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60; If all are in [ + 1, If the temperature falls within the range of 2], then proceed to the coil temperature abnormality judgment unit 34 and execute step S40; in, 2> 1; In cooling mode, determine the temperature at the bottom of the coil. and the temperature in the middle of the coil Is it in [ , Within the range: If none of them are [ , If the temperature is within the specified range, the first and second temperature sensors are determined to be faulty, triggering an alarm and shutdown. If only the temperature at the bottom of the coil is available exist[ , If the temperature is within the specified range, the first temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60. If only the temperature in the middle of the coil is present. exist[ , If the temperature is within the specified range, the second temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60. If all are in [ , If the temperature falls within the specified range, then the coil temperature abnormality judgment unit 34 will be entered, and step S40 will be executed. in, > .

[0015] Compared to existing technologies, this invention employs a dual-coil temperature control scheme during system operation. Specifically, it compares the absolute temperature difference between the bottom coil and the middle coil in the finned heat exchanger to ensure they fall within a set temperature difference threshold range. Combined with the heat pump system's operating mode and corresponding control logic, it selects either the bottom coil temperature, the middle coil temperature, or the average of both as the control parameter for refrigerant flow control, depending on the specific functional scenario. This dual-coil temperature control scheme effectively improves the accuracy of refrigerant flow control and fan speed control based on coil temperature, thereby enhancing the heat pump system's hot water control, cooling control, defrosting control, superheat control, and fan control. Features such as overheat protection for the cooling coil are more precise and timely, significantly improving the stability and reliability of the heat pump system and enhancing its adaptability to complex operating conditions. Temperature sensors are installed at both the bottom and middle of the finned heat exchanger, providing dual protection for coil temperature monitoring. Even if one sensor malfunctions, the other ensures normal system operation. Furthermore, when using the finned coil temperature as the condensing temperature in hot water mode, deviation compensation is applied to the coil temperature based on different ambient temperatures, making it closer to the system's true evaporation temperature, further enhancing the stability and reliability of the heat pump system.

[0016] Meanwhile, the present invention also provides a heat pump system, including a compressor, a reversing four-way valve, a water-side heat exchanger, a throttling assembly, and a finned heat exchanger connected by refrigerant piping, and a fan disposed on one side of the finned heat exchanger; a first temperature sensor is installed on the bottom coil of the finned heat exchanger, and a second temperature sensor is installed on the middle coil, the first and second temperature sensors being communicatively connected to a controller; the controller includes: an operating condition acquisition unit, a coil temperature acquisition unit, a coil temperature anomaly judgment unit, a first coil temperature determination unit, and a second coil temperature determination unit; The operating condition acquisition unit is used to acquire the operating mode of the heat pump system and the control logic corresponding to the current operating mode. The coil temperature acquisition unit is used to acquire the temperature at the bottom of the coil. and the temperature in the middle of the coil ; The coil temperature anomaly detection unit is used to calculate the temperature at the bottom of the coil. Temperature in the middle of the coil The absolute difference ΔTp is used to determine whether the absolute difference ΔTp is greater than or equal to the absolute difference threshold Δ. : If yes, proceed to the first coil temperature determination unit; If not, proceed to the second coil temperature determination unit; The first coil temperature determination unit is used in the exhaust superheat control logic of the cooling mode to determine... As a control coil temperature In other cases, As a control coil temperature ; The second coil temperature determination unit is used to determine the fan speed control logic or fin temperature overheat protection logic in the cooling mode. As a control coil temperature In the fan speed control logic of hot water mode or the fin temperature control logic of defrost mode, As a control coil temperature In other cases, As a control coil temperature ; in, This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The maximum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The minimum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The mean.

[0017] Furthermore, the controller also includes a temperature sensor for detecting ambient temperature, and an evaporation temperature calculation unit. This unit acquires the ambient temperature Ta when operating in hot water mode and determines the coil temperature compensation value ΔT based on the temperature range to which Ta belongs. R And based on the coil temperature compensation value △T R Temperature control coil The evaporation temperature T was calculated.E .

[0018] Furthermore, the controller also includes a condensing temperature calculation unit, which is used to obtain the coil temperature compensation value ΔT when operating in cooling mode or defrost mode. R According to the coil temperature compensation value △T R Temperature control coil The condensation temperature T was calculated. C .

[0019] The beneficial effects of the heat pump system provided by this invention are the same as those of a method for determining the temperature of a finned coil, and will not be repeated here.

[0020] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of the controller component in this invention. Detailed Implementation

[0022] Due to manufacturing process limitations, the temperature sensor used to detect the temperature of the finned coil is directly fixed to the coil of the finned heat exchanger and exposed to the external environment. When the system is running in cooling mode, the finned heat exchanger acts as a condenser. Because the actual condensation temperature is higher than the ambient temperature, the measured coil temperature will be lower than the actual condensation temperature. When the system is running in heating mode, the finned heat exchanger acts as an evaporator. Because the actual evaporation temperature is lower than the ambient temperature, the measured coil temperature will be higher than the evaporation temperature.

[0023] Therefore, the present invention provides a heat pump system with a method for determining the temperature of the finned coil, so that the coil temperature detected and corrected by the heat pump system is closer to the actual condensation temperature or the actual evaporation temperature.

[0024] Please see Figure 1 The heat pump system of the present invention includes a compressor 11, a reversing four-way valve 12, a finned heat exchanger 13, a throttling assembly 14 and a water-side heat exchanger 15, which are circulated through refrigerant pipelines, a fan 16 disposed on one side of the finned heat exchanger 13, a parameter measurement module 20, and a controller (not shown) that is communicatively connected to the parameter measurement module 20.

[0025] When the system is in heating mode, the finned heat exchanger 13 acts as an evaporator to transfer heat from the air to the low-temperature, low-pressure refrigerant; when the system is in cooling mode, the finned heat exchanger 13 acts as a condenser to transfer heat from the high-temperature, high-pressure refrigerant discharged from the compressor 11 to the working fluid water.

[0026] In a specific implementation, the finned heat exchanger 13 includes a coil and several fins disposed on the outer wall of the coil, wherein the coil is a spirally arranged copper tube.

[0027] The throttling component 14 is an electronic expansion valve.

[0028] The water-side heat exchanger 15 is a tubular heat exchanger or a plate heat exchanger.

[0029] The parameter measurement module 20 includes a first temperature sensor 21 installed on the bottom coil of the finned heat exchanger 13, a second temperature sensor 22 installed on the middle coil of the finned heat exchanger 13, a third temperature sensor 23 and a first pressure sensor (not shown) installed on the exhaust pipe of the compressor 11, a fourth temperature sensor 24 and a second pressure sensor (not shown) installed on the return pipe of the compressor 11, and an ambient temperature sensor (not shown) installed in the external environment.

[0030] The first temperature sensor 21 is used to measure the temperature at the bottom of the coil. and the temperature at the bottom of the coil Transmitted to the controller.

[0031] The second temperature sensor 22 is used to measure the temperature in the middle of the coil. and the temperature in the middle of the coil Transmitted to the controller.

[0032] The third temperature sensor 23 is used to measure the exhaust temperature Te and transmit the exhaust temperature Te to the controller.

[0033] The fourth temperature sensor 24 is used to measure the return gas temperature Ti and transmit the return gas temperature Ti to the controller.

[0034] The ambient temperature sensor is used to measure the ambient temperature Ta and transmit the ambient temperature Ta to the controller.

[0035] The first pressure sensor is used to measure the exhaust pressure and transmit the exhaust pressure to the controller.

[0036] The second pressure sensor (not shown) is used to measure the low pressure of the return gas and transmit the low pressure of the return gas to the controller.

[0037] Please see Figure 2 The controller 30 includes an operating condition acquisition unit 31, a coil temperature acquisition unit 32, a sensor anomaly judgment unit 33, a coil temperature anomaly judgment unit 34, a first coil temperature determination unit 35A, a second coil temperature determination unit 35B, an evaporation temperature calculation unit 36A, and a condensation temperature calculation unit 36B.

[0038] The operating condition acquisition unit 31 is used to execute step S10: acquire the operating mode of the heat pump system and the control logic corresponding to the current operating mode.

[0039] The operating modes include cooling mode, hot water mode, and defrosting mode.

[0040] The control logic corresponding to the current operating mode includes: When the operating mode is cooling mode, the control logic includes exhaust superheat control, fan speed control and fin overheat protection control. When the operating mode is hot water mode, the control logic includes return gas superheat control, wind speed control and fin temperature low protection control. When the operating mode is defrosting mode, the control logic includes fin temperature control.

[0041] The coil temperature acquisition unit 32 is used to perform step S20: acquire the temperature of the bottom of the coil. and the temperature in the middle of the coil .

[0042] The sensor anomaly detection unit 33 is used to execute step S30: based on the operating mode and the temperature at the bottom of the coil. and the temperature in the middle of the coil Determine if the first and second temperature sensors are faulty: If both the first and second temperature sensors are normal, then proceed to the coil temperature abnormality judgment unit 34 and execute step S40. If the first temperature sensor or the second temperature sensor is normal, then proceed to the evaporation temperature and condensation temperature calculation unit 36 ​​and execute step S60. In other cases, an alarm will sound and the system will be shut down.

[0043] Specifically, in hot water mode, the temperature at the bottom of the coil is determined. and the temperature in the middle of the coil Is it in [ + 1, Within the range of 2]: If none of them are [ + 1, If the temperature is within the range of 2], the first temperature sensor and the second temperature sensor are determined to be faulty, and an alarm is triggered to stop the machine; If only the temperature at the bottom of the coil is available exist[ + 1, If the temperature is within the range of 2], the first temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60; If only the temperature in the middle of the coil is present. exist[ + 1, If the temperature is within the range of 2], the second temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60; If all are in [ + 1, If the temperature falls within the range of 2], then proceed to the coil temperature abnormality judgment unit 34 and execute step S40; in, 2> 1, The pressure is obtained by measuring the low-pressure port of compressor 11 and referring to a table based on the refrigerant used in the system; in this embodiment, 1 represents 2℃ 2 is 5℃; In cooling mode, determine the temperature at the bottom of the coil. and the temperature in the middle of the coil Is it in [ , Within the range: If none of them are [ , If the temperature is within the specified range, the first and second temperature sensors are determined to be faulty, triggering an alarm and shutdown. If only the temperature at the bottom of the coil is available exist[ , If the temperature is within the specified range, the first temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60. If only the temperature in the middle of the coil is present. exist[ , If the temperature is within the specified range, the second temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60. If all are in [ , If the temperature falls within the specified range, then the coil temperature abnormality judgment unit 34 will be entered, and step S40 will be executed. in, > , The pressure is obtained by measuring the high-pressure outlet of compressor 11 and referring to a table based on the refrigerant used in the system; in this embodiment, 6℃ It is 2℃.

[0044] The coil temperature anomaly judgment unit 34 is used to execute step S40: calculate the temperature at the bottom of the coil. Temperature in the middle of the coil The absolute difference ΔTp is used to determine whether the absolute difference ΔTp is greater than or equal to the absolute difference threshold Δ. : If the absolute difference ΔTp is greater than or equal to the absolute difference threshold Δ Then determine the temperature at the bottom of the coil. and / or temperature in the middle of the coil If an abnormality is found, proceed to the first coil temperature determination unit 35A and execute step S50A; If the absolute difference ΔTp is less than the absolute difference threshold Δ Then determine the temperature at the bottom of the coil. and the temperature in the middle of the coil If no abnormalities are found, proceed to the second coil temperature determination unit 35B and execute step S50B.

[0045] In practical implementation, △Tp=| |. Absolute difference threshold △ The value range is 10℃~20℃.

[0046] The first coil temperature determination unit 35A executes step S50A: in the exhaust superheat control logic of the cooling mode, ... As a control coil temperature In other cases, As a control coil temperature .

[0047] The second coil temperature determination unit 35B executes step S50B: in the fan speed control logic or fin temperature overheat protection logic of the cooling mode, As a control coil temperature In the fan speed control logic of hot water mode or the fin temperature control logic of defrost mode, As a control coil temperature In other cases, As a control coil temperature .

[0048] Specifically, This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The maximum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The minimum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The mean.

[0049] The evaporation temperature calculation unit 36A is used to execute step S60A: when running the hot water mode, obtain the ambient temperature Ta; and determine the coil temperature compensation value △T according to the temperature range to which the ambient temperature Ta belongs. R And based on the coil temperature compensation value △T R Temperature control coil The evaporation temperature T was calculated. E .

[0050] In specific implementation, the first ambient temperature threshold is adopted. Second ambient temperature threshold The temperature range is divided into three temperature zones, corresponding to three different coil temperature compensation values, with evaporation temperature T. E The calculation is as follows: If the ambient temperature Ta ≥ the first ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ,in This is the temperature compensation value for the first coil; If the ambient temperature Ta ≤ the second ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ,in This is the temperature compensation value for the second coil; If the second ambient temperature threshold <Ambient temperature Ta < First ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + , This refers to the temperature compensation value for the third coil, where the temperature compensation value for the third coil is... satisfy; ; Among them, the second ambient temperature threshold <First ambient temperature threshold First coil temperature compensation value >Second coil temperature compensation value .

[0051] The condensing temperature calculation unit 36B is used to execute step S60B: when running the cooling mode or defrost mode, to obtain the coil temperature compensation value △T. R According to the coil temperature compensation value △T R Temperature control coil The condensation temperature T was calculated. C .

[0052] Specifically, condensation temperature T C = +△T R , where △T R The constant C is set.

[0053] For example, the operating modes of the heat pump system described in this invention and the control logic corresponding to the current operating mode include, but are not limited to: controlling the opening of the electronic expansion valve using the return gas superheat, controlling the opening of the electronic expansion valve using the exhaust gas superheat, and controlling the temperature of the control coil. Controlling the fan speed and utilizing the temperature of the control coil. Protect the compressor and utilize the temperature of the control coil. Control the defrosting of the finned heat exchanger.

[0054] Specifically, the control of the opening degree of the electronic expansion valve using the return gas superheat includes the following control methods: Obtain the return gas temperature Ti, and calculate the return gas temperature Ti and the control coil temperature. The difference is used to obtain the return gas superheat ΔTi; it is then determined whether the return gas superheat ΔTi is less than the return gas superheat threshold ΔTi. If the return gas superheat ΔTi is less than the return gas superheat threshold Δ If the return gas superheat ΔTi is greater than the return gas superheat threshold ΔTi, then reduce the opening of the electronic expansion valve; This increases the opening degree of the electronic expansion valve.

[0055] Specifically, the method of controlling the opening of the electronic expansion valve using exhaust superheat includes the following control methods: Obtain the exhaust temperature Te, calculate the exhaust temperature Te and the control coil temperature. The difference is used to obtain the exhaust superheat ΔTe; it is then determined whether the exhaust superheat ΔTe is less than the exhaust superheat threshold ΔTe. If the exhaust superheat ΔTe is less than the exhaust superheat threshold Δ If the exhaust superheat ΔTe is greater than the exhaust superheat threshold ΔTe, then reduce the opening of the electronic expansion valve; This increases the opening degree of the electronic expansion valve.

[0056] Specifically, the method of controlling the fan speed using the control coil temperature TC includes the following control methods: Determine the temperature of the control coil Is it less than the fan speed and coil temperature threshold? If controlling the temperature of the coil Less than the fan speed and coil temperature threshold If the fan speed is increased, the temperature of the control coil should be increased. The fan speed and coil temperature threshold are greater than the threshold value. This will reduce the fan speed.

[0057] Specifically, the use of control coil temperature Protecting the compressor includes the following control methods: Determine the temperature of the control coil High temperature protection threshold Low temperature protection threshold The relationship between them: If the temperature of the control coil is used Greater than the high temperature protection threshold Or control the temperature of the coil. Less than the low temperature protection threshold If the alarm is triggered, the machine will shut down.

[0058] Specifically, the use of control coil temperature Controlling defrosting of finned heat exchangers includes the following control methods: Determine the temperature of the control coil Is it less than the defrost threshold? If controlling the temperature of the coil Less than the defrost threshold Then defrosting will be initiated.

[0059] Compared to existing technologies, this invention employs a dual-coil temperature control scheme during system operation. Specifically, it compares the absolute temperature difference between the bottom and middle coil temperatures of the finned heat exchanger to ensure it falls within a set temperature difference threshold range. Combining this with the heat pump system's operating mode and corresponding control logic, it selects either the bottom coil temperature, the middle coil temperature, or the average of both as the control parameter for refrigerant flow control, depending on the specific functional scenario. This dual-coil temperature control scheme effectively improves the accuracy of refrigerant flow and fan speed control based on coil temperature, enhancing the heat pump system's hot water control, cooling control, defrosting control, and superheat control. The fan control and overheat protection functions for the cooling coils are more precise and timely, significantly improving the stability and reliability of the heat pump system and enhancing its adaptability to complex operating conditions. Meanwhile, temperature sensors are installed at the bottom and middle of the finned heat exchanger, providing dual protection for coil temperature monitoring. Even if one sensor malfunctions or malfunctions, the other sensor ensures normal system operation. Furthermore, when using the finned coil temperature as the condensing temperature in hot water mode, deviation compensation is applied to the coil temperature based on different ambient temperatures, making it closer to the system's true evaporation temperature, further enhancing the stability and reliability of the heat pump system.

[0060] 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 and claims of this application 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; the terms “first,” “second,” “third,” etc., are used only to distinguish and not to describe a particular order or sequence, nor should they be construed as indicating or implying relative importance. The term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items. When the above description relates to drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of this application, those skilled in the art will understand the specific meaning of the above terms in this application according to the specific circumstances.

[0061] 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 these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for determining the temperature of a finned coil, applicable to a heat pump system in which a first temperature sensor is installed on the bottom coil of the finned heat exchanger and a second temperature sensor is installed on the middle coil, characterized in that... Includes the following steps: S10: Obtain the operating mode of the heat pump system and the control logic corresponding to the current operating mode; S20: Obtain the temperature at the bottom of the coil. and the temperature in the middle of the coil ; S40: Calculate the bottom temperature of the coil Temperature in the middle of the coil The absolute difference ΔTp is used to determine whether the absolute difference ΔTp is greater than or equal to the absolute difference threshold Δ. : If so, proceed to step S50A; If not, proceed to step S50B; S50A: In the exhaust superheat control logic of cooling mode, As a control coil temperature In other cases, As a control coil temperature ; S50B: In the fan speed control logic or fin temperature overheat protection logic of cooling mode, As a control coil temperature In the fan speed control logic of hot water mode or the fin temperature control logic of defrost mode, As a control coil temperature In other cases, As a control coil temperature ; in, This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The maximum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The minimum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The mean.

2. The method for determining the temperature of the finned coil according to claim 1, characterized in that, Control the temperature of the coil As the evaporation temperature T E At the same time, it also includes S60A: When running in hot water mode, the ambient temperature Ta is obtained; the coil temperature compensation value △T is determined based on the temperature range to which the ambient temperature Ta belongs. R And based on the coil temperature compensation value △T R Temperature control coil The evaporation temperature T was calculated. E .

3. The method for determining the temperature of the finned coil according to claim 2, characterized in that, Using the first ambient temperature threshold Second ambient temperature threshold The temperature range is divided into three temperature zones, corresponding to three different side coil temperature compensation values, with evaporation temperature T. E The calculation is as follows: If the ambient temperature Ta ≥ the first ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ; If the ambient temperature Ta ≤ the second ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ; If the second ambient temperature threshold <Ambient temperature Ta < First ambient temperature threshold Coil temperature compensation value △T R = Then the evaporation temperature T E = + ; in, This is the temperature compensation value for the first coil. This is the temperature compensation value for the second coil. The temperature compensation value for the third coil is [value], and the temperature compensation value for the first coil is [value]. >Second coil temperature compensation value Second ambient temperature threshold <First ambient temperature threshold .

4. The method for determining the temperature of the finned coil according to claim 3, characterized in that, The third coil temperature compensation value satisfy: 。 5. The method for determining the temperature of the finned coil according to claim 1, characterized in that, Control the temperature of the coil As the condensation temperature T C At the same time, it also includes S60B: When operating in cooling or defrosting mode, obtain the coil temperature compensation value △T. R ; Based on the coil temperature compensation value △T R Temperature control coil The condensation temperature T was calculated. C : T C = +△T R , Among them, △T R The constant C is set.

6. The method for determining the temperature of the finned coil according to claim 1, characterized in that, It also includes step S30: Based on the operating mode and the temperature at the bottom of the coil and the temperature in the middle of the coil Determine if the first and second temperature sensors are faulty: If both the first and second temperature sensors are functioning normally, proceed to step S40. If both the first and second temperature sensors malfunction, an alarm will sound and the machine will shut down. If either the first or second temperature sensor is functioning correctly, then use the functioning one.

7. The method for determining the temperature of the finned coil according to claim 6, characterized in that, In hot water mode, determine the temperature at the bottom of the coil. and the temperature in the middle of the coil Is it in [ + 1, Within the range of 2]: If none of them are [ + 1, If the temperature is within the range of 2], the first temperature sensor and the second temperature sensor are determined to be faulty, and an alarm is triggered to stop the machine; If only the temperature at the bottom of the coil is available exist[ + 1, If the temperature is within the range of 2], the first temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60; If only the temperature in the middle of the coil is present. exist[ + 1, If the temperature is within the range of 2], the second temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60; If all are in [ + 1, If the temperature falls within the range of 2], then proceed to the coil temperature abnormality judgment unit 34 and execute step S40; in, 2> 1; In cooling mode, determine the temperature at the bottom of the coil. and the temperature in the middle of the coil Is it in [ , Within the range: If none of them are [ , If the temperature is within the specified range, the first and second temperature sensors are determined to be faulty, triggering an alarm and shutdown. If only the temperature at the bottom of the coil is available exist[ , If the temperature is within the specified range, the first temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60. If only the temperature in the middle of the coil is present. exist[ , If the temperature is within the specified range, the second temperature sensor is determined to be normal, and the process proceeds to the evaporation temperature and condensation temperature calculation unit 36 ​​to execute step S60. If all are in [ , If the temperature falls within the specified range, then the coil temperature abnormality judgment unit 34 will be entered, and step S40 will be executed. in, > .

8. A heat pump system, comprising a compressor, a reversing four-way valve, a water-side heat exchanger, a throttling assembly, and a finned heat exchanger connected via refrigerant piping, and a fan disposed on one side of the finned heat exchanger; characterized in that, The bottom coil of the finned heat exchanger is equipped with a first temperature sensor, and the middle coil is equipped with a second temperature sensor. The first and second temperature sensors are communicatively connected to the controller. The controller includes: an operating condition acquisition unit, a coil temperature acquisition unit, a coil temperature anomaly judgment unit, a first coil temperature determination unit, and a second coil temperature determination unit. The operating condition acquisition unit is used to acquire the operating mode of the heat pump system and the control logic corresponding to the current operating mode. The coil temperature acquisition unit is used to acquire the temperature at the bottom of the coil. and the temperature in the middle of the coil ; The coil temperature anomaly detection unit is used to calculate the temperature at the bottom of the coil. Temperature in the middle of the coil The absolute difference ΔTp is used to determine whether the absolute difference ΔTp is greater than or equal to the absolute difference threshold Δ. : If yes, proceed to the first coil temperature determination unit; If not, proceed to the second coil temperature determination unit; The first coil temperature determination unit is used in the exhaust superheat control logic of the cooling mode to determine... As a control coil temperature In other cases, As a control coil temperature ; The second coil temperature determination unit is used to determine the fan speed control logic or fin temperature overheat protection logic in the cooling mode. As a control coil temperature In the fan speed control logic of hot water mode or the fin temperature control logic of defrost mode, As a control coil temperature In other cases, As a control coil temperature ; in, This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The maximum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The minimum value; This indicates the temperature at the bottom of the coil. and the temperature in the middle of the coil The mean.

9. The heat pump system according to claim 8, characterized in that, The controller also includes a temperature sensor for detecting ambient temperature, and an evaporation temperature calculation unit for obtaining the ambient temperature Ta when operating in hot water mode; and determining the coil temperature compensation value ΔT based on the temperature range to which the ambient temperature Ta belongs. R And based on the coil temperature compensation value △T R Temperature control coil The evaporation temperature T was calculated. E .

10. The heat pump system according to claim 8 or 9, characterized in that, The controller also includes a condensing temperature calculation unit, which is used to obtain the coil temperature compensation value ΔT when running in cooling mode or defrost mode. R According to the coil temperature compensation value △T R Temperature control coil The condensation temperature T was calculated. C .

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