Anti-freezing control method and adjusting water valve for central heating system of air source heat pump

Abstract

The invention discloses an air source heat pump central heating system anti-freezing control method and an adjusting water valve which can be applied to a central heating system. The adjusting water valve comprises a valve body, an executing mechanism, a bypass pipe, a valve plate, a signal line, an electromagnetic valve, a controller and a flange. The control method comprises the following steps: setting preset temperatures Ta, Tb and Tc; continuously monitoring the on-off state of the heat pump unit, the outdoor temperature and the condenser temperature; and according to the conditions of the on-off state of the heat pump unit, the outdoor temperature and the condenser temperature, the water valve of the branch pipe where the heat pump unit is located is controlled. The control method is used on the adjusting water valve, it is ensured that the branch pipe where the heat pump unit is located and the condenser loop always maintain the adaptive water flow, the freezing risk caused by system loop water circulation interruption can be effectively avoided, safe operation of the heat pump unit is guaranteed, and the service life of the heat pump unit is prolonged. And bypass low-temperature water of the heat pump unit which is not operated can be prevented from being mixed, so that the energy consumption of the system is reduced, and the heat supply temperature stability of the system is improved.

Description

Technical Field

[0001] This invention relates to the technical field of air source heat pumps, and particularly to an antifreeze control method and regulating water valve for a centralized heating system using an air source heat pump. Background Technology

[0002] Air source heat pump district heating systems are increasingly widely used in the field of district heating due to their high efficiency, energy saving, low carbon and environmental protection characteristics. The system absorbs low-grade heat energy from the air through heat pump units, and after energy conversion, it delivers heat to the district heating area. Its stable operation is directly related to the reliability of heating and energy utilization efficiency.

[0003] In engineering projects, multiple heat pump units are often used in parallel. To prevent the return water from the heating system from passing through the stopped heat pump unit when one or more units are shut down, thus causing mixing and a drop in supply water temperature, traditional electric two-position valves are usually installed on the branch pipe of each heat pump unit in practical applications. These electric two-position valves are interlocked with the heat pump units for start-stop control to avoid the aforementioned situation. However, while the traditional electric two-position valves on the branch pipes solve the problem of mixing when multiple units are operating in parallel, they cannot prevent the risk of condensers gradually losing temperature and freezing when used in extremely cold regions, as the water circulation in the heat pump unit's branch pipe loop is cut off.

[0004] Therefore, to address the aforementioned antifreeze requirements, an antifreeze technology solution needs to be proposed that can combine the unit's operating status with multiple temperature parameters to achieve precise linkage control.

[0005] Existing patent CN218442509U discloses an automatic anti-freezing mechanism for an air source heat pump unit and its outdoor pipes during winter power outages. This mechanism includes a wall and heating pipes. The left side of the wall is indoors, and the right side is outdoors. The heating pipes penetrate the wall, and a water supply system connected to the interior of the heating pipes is fixedly installed at the lowest end of the pipes. A constant pressure water supply device is installed on the side wall of the heating pipes on the left side of the wall. This constant pressure water supply device consists of a constant pressure water supply valve and a check valve. In this invention, the water supply system supplies water to the interior of the heating pipes, while the check valve prevents backflow of water from the heating pipes. Once the water pressure in the heating pipes returns to normal, the water supply system stops and resumes operation. This prevents water from accumulating and freezing in the outdoor unit's water system and pipes due to low ambient temperatures during prolonged power outages, which could damage the unit or pipe valves and other components, affecting system operation. The anti-freezing logic of this patent mainly relies on a single trigger condition of "power outage," achieving protection through drainage via an electric two-position valve. This patent cannot solve the problem of water mixing, and its antifreeze logic is simplistic.

[0006] Existing patent CN109323477B discloses a transcritical CO2 heat pump system with a precooler and its water circuit two-way valve control method. This method includes: supplementing a conventional transcritical CO2 heat pump system with a precooler system; dividing the circulating water circuit into two parts within the system via a three-way distributor valve and a three-way manifold valve, and connecting them via a two-way regulating valve and a bypass valve; simultaneously incorporating an ambient temperature sensor, an evaporator fin temperature sensor, and an evaporation pressure sensor, with a programmable logic controller (PLC) as the core for data acquisition, calculation, and control. Through the above system configuration and a properly formulated temperature, pressure, and time-based joint control method, the transcritical CO2 heat pump system can be promoted to the heating field, compensating for the performance degradation of the transcritical CO2 system due to high return water temperature, properly controlling the unit's entry and exit from defrosting, and solving the problem of a rapid drop in the average temperature of the circulating water system when the transcritical CO2 heat pump system stops supplying heat during a relatively long defrosting period. This patented valve is only used to regulate the diversion and bypass of circulating water. It does not have an anti-mixing structure designed for multi-unit parallel operation scenarios, and cannot solve the problem of reduced water supply temperature caused by unit shutdown. At the same time, the antifreeze function is an auxiliary function and not specific enough, and antifreeze is only an incidental effect of the defrosting process.

[0007] Existing patent JPH09229477A discloses an antifreeze method and device for a hot water supply system, as well as a low-temperature driven drain valve for the system. This method utilizes a low-temperature driven drain valve; when the water temperature inside the system drops below a specific temperature, a temperature-sensitive element drives the drain valve to open, draining accumulated water and preventing the system from freezing and damaging it. This patent focuses on the antifreeze requirements of hot water supply systems, achieving protection through a combination of electric heater heating and low-temperature valve drainage. However, this patent does not consider the issue of preventing water mixing when multiple devices are connected in parallel, resulting in a simplistic antifreeze logic. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and to propose an antifreeze control method and regulating water valve for an air source heat pump centralized heating system.

[0009] In a first aspect, the present invention provides an antifreeze regulating water valve for an air source heat pump centralized heating system. The antifreeze regulating water valve utilizes the aforementioned antifreeze control method for an air source heat pump centralized heating system. The structure of the antifreeze regulating water valve is as follows: Figure 2 or Figure 3 As shown, it specifically includes: 1. Valve body; 2. Actuator; 3. Bypass pipe; 4. Valve plate; 5. Signal line; 6. Solenoid valve; 7. Controller; 8. Flange. The valve body 1 is connected to the branch pipe of the heat pump unit or cluster via the flange 8. The bypass pipe 3 is connected to the valve body 1. The actuator 2 is connected to the valve plate 4, and the valve plate 4 controls the opening and closing of the valve body 1; the actuator 2 is connected to the controller 7 via the signal line 5. The controller 7 is also connected to the solenoid valve 6 via the signal line 5, and the solenoid valve 6 controls the opening and closing of the bypass pipe 3. It also includes temperature sensors, which are communicatively connected to the controller 7; there are multiple temperature sensors, distributed in the outdoor space of the project site and in the condenser of the heat pump unit.

[0010] Preferably, the controller 7 is connected to the unit start-stop cabinet via the signal line 5 to read the start-stop status of the heat pump unit.

[0011] Preferably, the minimum nominal diameter of the bypass pipe 3 is determined by the following formula:

[0012] In the formula, This is the minimum nominal diameter of the bypass pipe 3 mentioned above, in millimeters; The water pressure drop in the branch where the heat pump is located when the above-mentioned antifreeze regulating water valve is fully open and the medium passes through the above-mentioned heat pump at the rated flow rate is expressed in Pascals. The thermal conductivity coefficient of the heat pump condenser is expressed in watts per square kelvin. The above refers to the temperature of the heat pump condenser, in degrees Celsius. The outdoor temperature of the aforementioned centralized heating area is expressed in degrees Celsius. The heat dissipation area of ​​all heat pump condensers and pipes is expressed in square meters. The specific heat capacity of the medium flowing through the above-mentioned antifreeze regulating water valve is expressed in joules per kilogram per degree Celsius. The water supply temperature is based on the design of the heating system, and the unit is degrees Celsius. The return water temperature is based on the design of the heating system, and the unit is degrees Celsius. Formula 1 above is derived from Formulas 2 through 6 below: Formula 2:

[0013] In the formula, The heat exchange capacity between all heat pump condensers and pipes connected to the branch pipe where the above-mentioned antifreeze regulating water valve is located and the outdoor air is expressed in watts. The heat required to supply the medium flowing through the above-mentioned antifreeze regulating water valve bypass pipe 3, in watts; Formula 3:

[0014] Formula 4:

[0015] In the formula, The mass flow rate of the medium flowing through the bypass pipe 3 of the above-mentioned antifreeze regulating water valve per unit time is expressed in kilograms per second. Formula 5:

[0016] Formula Six:

[0017] In the formula, This is an empirical fitting function used to determine the nominal diameter of the bypass pipe based on the above S; The overall network resistance of the branch pipe when the bypass pipe 3 of the above-mentioned antifreeze regulating water valve is in the open state.

[0018] In a second aspect, the present invention provides a method for antifreeze control of an air source heat pump centralized heating system, such as... Figure 1 As shown, it includes the following steps: S1. Continuously monitor the start-up and shut-down status of the heat pump unit, outdoor temperature, and condenser temperature. S2. If the above heat pump unit is detected to be in the on state, control the solenoid valve and actuator to open, and return to S1; otherwise, proceed to S3. S3. If the outdoor temperature is detected to be greater than the preset temperature Ta, control the solenoid valve and the actuator to close and return to S1; otherwise, proceed to S4. S4. If the temperature of the condenser is detected to be greater than the preset temperature Tb, control the solenoid valve to open and the actuator to close, and return to S1; otherwise, proceed to S5. S5. Control the opening of the above-mentioned solenoid valve and the above-mentioned actuator; Continue monitoring the condenser temperature until it is greater than or equal to the preset temperature Tc, then control the solenoid valve to open and the actuator to close, and return to S1.

[0019] Preferably, the preset temperature Ta is 0℃~2℃, the preset temperature Tb is 2℃~5℃, and the preset temperature Tc is 15℃~40℃.

[0020] Preferably, when the branch pipe of the aforementioned heat pump unit is connected to multiple heat pump units, the aforementioned condenser temperature is the lowest among all condenser temperatures.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides an antifreeze regulating water valve and method for a centralized air source heat pump heating system. The antifreeze regulating water valve is electrically connected to an actuator and a solenoid valve via a controller, precisely controlling valve plate deflection and bypass pipe opening / closing. Utilizing the aforementioned antifreeze control method, the antifreeze regulating water valve achieves interlocking start / stop with the heat pump unit, ensuring a consistent water flow meeting antifreeze requirements through all pipes and the condenser under different conditions. This solves the problems of significant water mixing and failure to prevent freezing after the heat pump unit is shut down, which are common with traditional methods. Furthermore, this antifreeze water valve avoids the use of electric heat tracing and antifreeze, significantly reducing the operating and maintenance costs of the centralized heating system and greatly lowering the antifreeze control requirements for the heat pump unit. Attached Figure Description

[0022] Figure 1 A flowchart of an antifreeze control method for an air source heat pump centralized heating system; Figure 2 A schematic diagram of an antifreeze regulating water valve with bypass function when the valve plate is closed; Figure 3 A schematic diagram of an antifreeze regulating water valve with bypass function when the valve plate is open; Figure 4 This is a control flowchart of the antifreeze regulating water valve in Example 1; Figure 5 A schematic diagram of multiple heat pump units connected in parallel; Figure 6 This is a schematic diagram of a structure where multiple heat pump groups are connected in parallel.

[0023] Marked in the image: 1. Valve body; 2. Actuator; 3. Bypass pipe; 4. Valve plate; 5. Signal line; 6. Solenoid valve; 7. Controller; 8. Flange; a. The medium flowing through the bypass pipe; b. The medium flowing through the valve body; a+b. The medium flowing through the branch pipe where the heat pump unit is located; Ⅰ. Antifreeze regulating water valve; Ⅱ-1. Heat pump unit No. 1; Ⅱ-n. Heat pump unit No. n; Ⅱ-1(1). Heat pump unit No. 1 in heat pump group 1; Ⅱ-1(n). Heat pump unit No. n in heat pump group 1; Ⅱ-n(n). Heat pump unit No. n in heat pump group 1; Ⅱ-n(n). Heat pump unit No. n in heat pump group 2; Ⅲ. Branch pipe connecting a single heat pump unit; Ⅳ. Branch pipe connecting multiple heat pump units; Ⅴ. Main inlet and outlet water pipes of heat pump units; Ⅵ. Control cabinet. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0025] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0026] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0027] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0028] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0029] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0030] Example 1 The heating system of a residential community adopts a structure in which multiple heat pump units are connected in parallel to form a heat pump cluster. This heat pump cluster contains 5 heat pump units, and the structure is as follows: Figure 5 As shown, at this time Figure 5 In this configuration, n=5. Each heat pump unit is connected to the main inlet and outlet water pipe V via branch pipe III. Water can flow naturally between the heat pump units. Each branch pipe III is equipped with an antifreeze regulating valve I. The specific structure of the antifreeze regulating valve I is as follows: Valve body, actuator, bypass pipe, valve plate, signal line, solenoid valve, controller, flange, temperature sensor.

[0031] The valve body is connected to the branch pipe where the heat pump unit is located via the flange. The aforementioned bypass pipe is connected to the aforementioned valve body; The aforementioned actuator is connected to the aforementioned valve plate, which controls the opening and closing of the aforementioned valve body; the aforementioned actuator is communicatively connected to the aforementioned controller via the aforementioned signal line. The controller is also connected to the solenoid valve via the signal line, and the solenoid valve controls the opening and closing of the bypass pipe.

[0032] The temperature sensors are communicatively connected to the controller and are located in the outdoor space of the project site and in the condenser of the heat pump unit. The aforementioned controller can be installed in control cabinet VI; The aforementioned antifreeze regulating water valve I utilizes one of the aforementioned antifreeze control methods for a centralized air source heat pump heating system; the specific flow of the aforementioned control method is as follows: Figure 4 As shown.

[0033] Operating conditions: During a winter night, the outdoor temperature is -2℃. Input the preset temperatures Ta as 0℃, Tb as 5℃, and Tc as 15℃ into the controller.

[0034] Due to a reduction in system load, three heat pump units (II-1, II-2, and II-3) were shut down; the remaining two heat pump units (II-4 and II-5) remained on. After some heat pump units were shut down, the lowest temperature measured for all condensers in the heat pump cluster was 4°C.

[0035] Regarding the operation of the antifreeze regulating water valve I on branch pipe III connected to heat pump units II-1, II-2, and II-3: S1. The controller continuously monitors the start-up and shut-down status of the heat pump unit, the outdoor temperature, and the condenser temperature. S2, The controller detects that the heat pump unit is in a shut-off state and proceeds to S3; S3: The controller detects that the outdoor temperature is less than 0℃ and proceeds to S4; S4. The controller detects that the condenser temperature is less than 5°C and proceeds to S5. S5. The controller controls the above-mentioned solenoid valve and the above-mentioned actuator to open (at this time, the above-mentioned bypass pipe is in the open state, the above-mentioned actuator controls the above-mentioned valve plate to deflect to the above-mentioned valve body channel to be fully open, and the water flows through the valve body channel and the bypass pipe). The controller continues to monitor the condenser temperature until it is greater than or equal to 15°C. Then, it controls the solenoid valve to open and the actuator to close (at this time, the bypass pipe is open, and the actuator controls the valve plate to deflect until the valve body channel is completely closed, and water flows only through the bypass pipe). Then, it returns to S1 to enter the control cycle.

[0036] Regarding the operation of the antifreeze regulating water valve I on branch pipe III connected to heat pump units II-4 and II-5: S1. The controller continuously monitors the start-up and shut-down status of the heat pump unit, the outdoor temperature, and the condenser temperature. S2. The controller detects that the heat pump unit is in the on state and controls the solenoid valve and the actuator to open (at this time, the bypass pipe is in the open state, and the actuator controls the valve plate to deflect to the valve body channel to be fully open, and water flows through the valve body channel and the bypass pipe), and then returns to S1 to enter the control cycle.

[0037] Example 2 A commercial park's heating system comprises three heat pump clusters. The structure of this heating system is as follows: Figure 6 As shown, at this time Figure 6 The value of n outside the square brackets is 3.

[0038] In a single heat pump cluster, each heat pump unit is connected to branch pipe IV via branch pipe III; each heat pump cluster is then connected to the main inlet and outlet water pipe V of the heat pump units via branch pipe IV. Both branch pipe III and branch pipe IV are equipped with an antifreeze regulating valve I. Water flow can naturally circulate between the heat pump units through the aforementioned main inlet and outlet water pipe V, branch pipe III, and branch pipe IV. The specific structure of the aforementioned antifreeze regulating valve I is as follows: Valve body, actuator, bypass pipe, valve plate, signal line, solenoid valve, controller, flange, temperature sensor.

[0039] The valve body is connected to the branch pipe where the heat pump unit is located via the flange. The aforementioned bypass pipe is connected to the aforementioned valve body; The aforementioned actuator is connected to the aforementioned valve plate, which controls the opening and closing of the aforementioned valve body; the aforementioned actuator is communicatively connected to the aforementioned controller via the aforementioned signal line. The controller is also connected to the solenoid valve via the signal line, and the solenoid valve controls the opening and closing of the bypass pipe.

[0040] The temperature sensors are communicatively connected to the controller and are located in the outdoor space of the project site and in the condenser of the heat pump unit. The aforementioned controller can be installed in control cabinet VI; The aforementioned antifreeze regulating water valve I utilizes one of the aforementioned antifreeze control methods for a centralized air source heat pump heating system; the specific flow of the aforementioned control method is as follows: Figure 4 As shown.

[0041] Operating conditions: During the winter cold wave, power supply was suspended in some areas of the park, and all heat pump units in heat pump clusters No. 2 and No. 3 were shut down; all heat pump units in heat pump cluster No. 1 remained on; the outdoor temperature was -5℃.

[0042] The preset temperatures Ta is set to 2℃, T2 to 2℃, and T3 to 40℃ in the controller. After heat pump units 2 and 3 are shut down, the condenser temperature is measured to be 2℃.

[0043] The operation of the antifreeze regulating water valve I on branch pipe III connected to heat pump clusters 2 and 3, and on branch pipe IV where all connected heat pump units are in a closed state: S1. The controller continuously monitors the start-up and shut-down status of the heat pump unit, the outdoor temperature, and the condenser temperature. S2, The controller detects that the heat pump unit is in a shut-off state and proceeds to S3; S3: The controller detects that the outdoor temperature is less than 2℃ and proceeds to S4; S4. The controller detects that the condenser temperature is 2℃ and proceeds to S5. S5. The controller controls the above-mentioned solenoid valve and the above-mentioned actuator to open (at this time, the above-mentioned bypass pipe is in the open state, the above-mentioned actuator controls the above-mentioned valve plate to deflect to the above-mentioned valve body channel to be fully open, and the water flows through the valve body channel and the bypass pipe). The controller continues to monitor the condenser temperature until it is greater than or equal to 40°C. Then, it controls the solenoid valve to open and the actuator to close (at this time, the bypass pipe is open, and the actuator controls the valve plate to deflect until the valve body channel is completely closed, and water flows only through the bypass pipe). Then, it returns to S1 to enter the control cycle.

[0044] Regarding the operation of the antifreeze regulating valve I on branch pipe III connected to heat pump group No. 1, and on branch pipe IV connected to heat pump units that are in the open state: S1. The controller continuously monitors the start-up and shut-down status of the heat pump unit, the outdoor temperature, and the condenser temperature. S2. The controller detects that the heat pump unit is in the on state and controls the solenoid valve and the actuator to open (at this time, the bypass pipe is in the open state, and the actuator controls the valve plate to deflect to the valve body channel to be fully open, and water flows through the valve body channel and the bypass pipe), and then returns to S1 to enter the control cycle.

[0045] Example 3 In a residential community's air source heat pump centralized heating system, a bypass pipe with an antifreeze regulating water valve needs to be designed for the branch pipe where each heat pump unit is located. Given the system operating parameters as follows, the minimum nominal diameter of the bypass pipe needs to be calculated.

[0046] System operating parameters: =15000Pa, =60W / (m²·K), =12℃, =-3℃, =8m², =4200J / (kg·℃), =55℃, =45℃.

[0047] (1) Calculate the heat exchange quantity

[0048]

[0049] Substituting the data, we get: =60×[12-(-3)]×8=7200W (2) Calculate the mass flow rate of the medium

[0050]

[0051]

[0052] It can be deduced that = / =7200 / 4200×(55-45)≈0.171kg / s (3) Calculate the comprehensive resistance of the pipeline network

[0053]

[0054] Substituting the data, we get: 15000 / (0.171)²≈513698Pa·s² / kg² (4) Calculate the nominal diameter of the bypass pipe :

[0055] Substitute the data and combine it with engineering experience functions ≈0.05× ×1000mm

[0056] Substitution value: ≈0.05× ×1000≈21mm Referring to the standard for nominal pipe diameter, the nominal diameter of the bypass pipe is taken as 25mm.

[0057] Under this operating condition, the nominal diameter of the bypass pipe of the antifreeze regulating water valve should be designed to be at least 25mm to meet the medium flow and resistance requirements required for system antifreeze.

Claims

1. An antifreeze regulating water valve for an air source heat pump centralized heating system, characterized in that, The structure of the antifreeze regulating water valve includes: Valve body (1), actuator (2), bypass pipe (3), valve plate (4), signal line (5), solenoid valve (6), controller (7), flange (8); The valve body (1) is connected to the branch pipe where the heat pump unit or cluster is located via the flange (8); The bypass pipe (3) is connected to the valve body (1); The actuator (2) is connected to the valve plate (4), and the valve plate (4) controls the opening and closing of the valve body (1); the actuator (2) is connected to the controller (7) through the signal line (5); The controller (7) is also connected to the solenoid valve (6) via the signal line (5), and the solenoid valve (6) controls the opening and closing of the bypass pipe (3); It also includes a temperature sensor, which is communicatively connected to the controller (7); there are multiple temperature sensors, which are distributed in the outdoor space of the project site and in the condenser of the heat pump unit.

2. The antifreeze regulating water valve for an air source heat pump centralized heating system according to claim 1, characterized in that, The controller (7) is connected to the unit start-stop cabinet through the signal line (5) to read the start-stop status of the heat pump unit.

3. The antifreeze regulating water valve for an air source heat pump centralized heating system according to claim 1, characterized in that, The minimum nominal diameter of the bypass pipe (3) is determined by the following formula: In the formula, The The minimum nominal diameter of the bypass pipe (3) is in millimeters; The The water pressure drop in the branch where the heat pump unit is located when the antifreeze regulating water valve is fully open and the medium passes through the heat pump unit at the rated flow rate is expressed in Pascals. The The thermal conductivity coefficient of the condenser of the heat pump unit is expressed in watts per square kelvin. The The temperature of the condenser of the heat pump unit is in degrees Celsius. The The outdoor temperature of the central heating area is expressed in degrees Celsius. The The heat dissipation area of ​​the condenser and piping for all heat pump units, in square meters; The The specific heat capacity of the medium flowing through the antifreeze regulating water valve is expressed in joules per kilogram per degree Celsius. The The water supply temperature is based on the design of the heating system, and the unit is degrees Celsius. The The return water temperature is based on the design of the heating system, and the unit is degrees Celsius.

4. A method for antifreeze control in an air source heat pump centralized heating system, characterized in that, The antifreeze control method is used for the antifreeze regulating water valve of any one of the air source heat pump centralized heating systems according to claims 1 to 3, and includes the following steps: S1. Continuously monitor the start-up and shut-down status of the heat pump unit, outdoor temperature, and condenser temperature. S2. If the heat pump unit is detected to be in the on state, control the solenoid valve and actuator to open, and return to S1; otherwise, proceed to S3. S3. If the outdoor temperature is detected to be greater than the preset temperature Ta, control the solenoid valve and the actuator to close and return to S1; otherwise, proceed to S4. S4. If the condenser temperature is detected to be greater than the preset temperature Tb, control the solenoid valve to open and the actuator to close, and return to S1; otherwise, proceed to S5. S5. Control the solenoid valve and the actuator to open; Continue monitoring the condenser temperature until it is greater than or equal to the preset temperature Tc, then control the solenoid valve to open, the actuator to close, and return to S1.

5. The antifreeze control method for an air source heat pump centralized heating system according to claim 4, characterized in that, The preset temperature Ta is 0℃~2℃, the preset temperature Tb is 2℃~5℃, and the preset temperature Tc is 15℃~40℃.

6. The antifreeze control method for an air source heat pump centralized heating system according to claim 4, characterized in that, When the branch pipe of the heat pump unit is connected to multiple heat pump units, the condenser temperature is the lowest among all condenser temperatures.

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