A decoupled high-efficiency central air-conditioning cooling water control system and method

Abstract

The invention discloses a decoupled high-efficiency central air-conditioning cooling water control system and method. The decoupled high-efficiency central air-conditioning cooling water control system comprises a modular cooling water pump energy efficiency control cabinet group consisting of a host and multiple slaves. The cabinets of the host and each slave are equipped with a power system unit, a speed regulation system unit and a control system unit. The control system unit sends the calculation result to the speed regulation system unit. The control system units of the host and the slave are connected through a communication interaction network. A flow balancing valve and a signal probe group are connected to the control system unit of the host. Each host or slave is used to drag a water pump. The host is used to obtain and calculate the operating condition information of the cooling water system and allocate and schedule the slaves. When the communication network is normal, the host is responsible for allocating and scheduling the operation. When the communication network is abnormal, the slave maintains the current state operation. The energy efficiency management and control platform is connected to the host of the modular cooling water pump energy efficiency control cabinet group to exchange data.

Description

Technical Field

[0001] The invention relates to a decoupled high-efficiency central air-conditioning cooling water control system and method, belonging to the technical field of energy-saving control of large-scale water-cooled central air-conditioning. Background Art

[0002] In the field of energy-saving control systems for large water-cooled central air conditioners, almost all energy-saving controls for central air conditioner systems in the prior art adopt system-integrated BA system control (Building Automation System). The principle of this control form is as follows: Figure 1 As shown in the figure, the advantages of this form of control are: (1) DDC controller can be selected, TCP / IP protocol is adopted, Ethernet communication network is realized, and communication rate is high; (2) system group control, control loop is relatively centralized, only one application program is needed to meet the operation of the entire system; (3) control scheme can be downloaded on-site by computer, which is flexible to use; (4) control scheme is preset in DDC, which is convenient for installation and debugging. A variety of data communication methods are suitable for various controlled devices and realize system integration.

[0003] Due to the above advantages, BA system control is widely used in central air-conditioning energy-saving control systems in various building construction, industrial control, intelligent instrumentation and other fields. However, this BA system control still has the following disadvantages:

[0004] (1) If the signal probe fails, the entire system will be out of control;

[0005] (2) If the DDC controller fails, the entire system will fail to operate and the security level will be low;

[0006] (3) Professionals are required to perform on-site programming and debugging. The implementation cycle of the system is relatively long. Summary of the invention

[0007] The purpose of the present invention is to provide a decoupled high-efficiency central air-conditioning cooling water control system with a high safety factor, which will not cause the entire system to fail to operate normally due to signal probe failure or controller abnormality. At the same time, the present invention also provides a control method for the decoupled high-efficiency central air-conditioning cooling water control system.

[0008] The decoupled high-efficiency central air-conditioning cooling water control system of the present invention adopts the following technical scheme: a decoupled high-efficiency central air-conditioning cooling water control system, which includes a cooling tower system group, a main unit group, and a cooling water pump group. A main unit group main water inlet pipe is connected between the total outlet of the cooling water pump group and the total inlet of the main unit group, a main unit main water outlet pipe is connected between the total outlet of the main unit group and the total inlet of the cooling tower system group, a main return water pipe is connected between the total outlet of the cooling tower system group and the total inlet of the cooling water pump group, a flow balance pipe is connected between the main unit main water outlet pipe and the main return water pipe, the flow balance pipe is less than or equal to the diameter of the main return water pipe or the main unit group main water outlet pipe, a flow balance valve is provided on the flow balance pipe, and the flow balance valve is an electric valve. The decoupled high-efficiency central air-conditioning cooling water control system also includes a signal probe group, a modular cooling water pump energy efficiency control cabinet group, and an energy efficiency management and control platform;

[0009] There are two groups of signal probes. The first group is a pressure sensor and a temperature sensor installed on the main water inlet pipe of the main unit. The second group is a pressure sensor and a temperature sensor installed on the main water outlet pipe of the main unit.

[0010] The modular cooling water pump energy efficiency control cabinet group includes a host and one or more slaves. The cabinets of the host and each slave are equipped with a power system unit, a speed control system unit and a control system unit. The control system unit sends the calculation results to the speed control system unit. The control system units of the host and the slave are connected through a communication interaction network. The signal end of the flow balancing valve and each signal probe group are uniformly connected to the control system unit of the host. The signal end of each water pump in the cooling water pump group is respectively connected to the control system unit of the host and the slave. Each host or slave is used to drive a water pump. The host is used to obtain and calculate the operating condition information of the cooling water system and allocate and schedule the slave. When the communication network is normal, the host is responsible for allocating and scheduling the operation. When the communication network is abnormal, the slave maintains the current state of operation; the energy efficiency management and control platform is connected to the host of the modular cooling water pump energy efficiency control cabinet group for data exchange.

[0011] The host and each slave are designed with integrated strong and weak electricity, and there are up to 7 slaves.

[0012] The host and slave use RS485 interface to realize hand-in-hand communication interactive network connection.

[0013] The decoupled high-efficiency central air-conditioning cooling water control method of the present invention adopts the following technical scheme: a decoupled high-efficiency central air-conditioning cooling water control method, the signal probe group and the signal end of the flow balance valve are connected to the host of the modular cooling water pump energy efficiency control cabinet group, and the flow balance calculation and energy efficiency control calculation are performed, each signal probe group is used to collect the temperature and pressure values ​​at the corresponding pipeline, the pressure and temperature measured by the pressure sensor and temperature sensor installed on the main water outlet pipe of the main unit group are P0 and T1 respectively, and the pressure and temperature measured by the pressure sensor and temperature sensor installed on the main water outlet pipe of the main unit group are P1 and T0 respectively;

[0014] The flow balancing valve calculation is as follows:

[0015] (1) When the cooling water current T1 is lower than the set minimum cooling water return temperature, the flow balance valve begins to adjust;

[0016] (2) Collect the month-on-month changes in T1 to determine whether the temperature trend is rising, flat or falling: take a fixed time period as a cycle, record the current T1 as before T1, and T1 after one cycle as after T1; current ΔT = before T1 - after T1, after n cycles, ΣΔT = ΔT1 + ΔT2 + ΔT3 + ... ΔTn, if ΣΔT is greater than 0, the temperature is on an upward trend, if ΣΔT is equal to 0, the temperature is on a flat trend, if ΣΔT is less than 0, the temperature is on a downward trend;

[0017] (3) When the return water temperature is on the rise, the opening of the flow balancing valve gradually decreases. When the return water temperature changes from the previous month to a flat state, the current valve position is maintained.

[0018] (4) When the return water temperature is decreasing, the opening of the flow balancing valve gradually increases. When the month-on-month change trend of the return water temperature turns to a flat state, the current valve position is maintained;

[0019] When the outdoor temperature is low, the water temperature is increased by opening the flow balancing valve; when the outdoor temperature is high, the flow balancing valve is gradually closed.

[0020] The energy efficiency control algorithm includes the basic algorithm and the load temperature difference flow correction algorithm, which are as follows:

[0021] 1. Basic algorithm:

[0022] The host side is the target:

[0023] Current total traffic ΔPPV 总 = Current host traffic ΔPPV 主机端 ,

[0024] Total flow demand ΔPSV 总 = Host-side traffic demand ΔPSV 主机端 ,

[0025] Among them, the current host traffic ΔPPV 主机端 =P0-P1, host-side traffic demand ΔPSV 主机端 It is a man-made setting;

[0026] 2. Load temperature difference flow correction algorithm:

[0027] (1) Host-side upper and lower limit calculation

[0028] a) Host-side ΔT correction ΔP compensation upper limit = total flow demand ΔPSV 总 × Host-side ΔT correction ΔP compensation upper limit ratio;

[0029] b) Host-side ΔT correction ΔP compensation lower limit = total flow demand ΔPSV 总 × Host-side ΔT correction ΔP compensation lower limit ratio;

[0030] The upper limit ratio of ΔT correction ΔP compensation on the host side and the lower limit ratio of ΔT correction ΔP compensation on the host side are both set manually;

[0031] (2) If the flow balancing valve compensation is turned on, the calculation starts, otherwise the compensation value is 0:

[0032] Among them, the host end sampling temperature difference = T1-T0, and the host end standard working condition temperature difference adopts the set standard value;

[0033] a) When the host-side sampled temperature difference is less than the host-side standard operating temperature difference, the host-side ΔT correction ΔP compensation value starts from 0, and when the custom pulse time is up, it is reduced by the set fixed value, and the cycle repeats. When the host-side ΔT correction ΔP compensation value is equal to the host-side ΔT correction ΔP compensation lower limit, the reduction of the set fixed value stops;

[0034] b) When the host-side sampling temperature difference is greater than the host-side standard operating temperature difference, the host-side ΔT correction ΔP compensation value starts from 0, and when the custom pulse time is up, the set fixed value is added, and the cycle repeats. When the host-side ΔT correction ΔP compensation value is greater than or equal to the host-side ΔT correction ΔP compensation upper limit value, the set fixed value is stopped;

[0035] Flow balancing valve compensation opening operation result: The actual flow rate of the cooling water pump is always measured by the current total flow rate ΔPPV 总 ΔPSV vs. total flow demand 总 By increasing or decreasing the flow balance valve opening to ensure the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , if the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , the cooling water pump maintains its current work unchanged.

[0036] The energy efficiency control algorithm also includes a temperature trend prediction and compensation algorithm, specifically:

[0037] When the T2 sampling temperature is less than or equal to the starting temperature, the host end standard operating temperature difference increases by 0.1°C every minute;

[0038] When the T2 sampling temperature is greater than or equal to the end temperature, the host end standard operating temperature difference decreases by 0.1°C every 1 minute;

[0039] The starting temperature and ending temperature are both set values.

[0040] The standard operating temperature difference of the host end is 5°C, the starting temperature is the standard operating temperature of 32°C, and the ending temperature is 37°C.

[0041] The range of the flow balancing valve opening is 0~100%, and the amount of increase or decrease in the flow balancing valve opening per 1s cycle is 0.5% of the maximum opening.

[0042] The minimum return temperature of cooling water is set at 26℃.

[0043] When collecting the month-on-month change of T1, the fixed time period used is 60 seconds.

[0044] The custom pulse time is 60-120s, and the set fixed value is 1Kpa.

[0045] Beneficial effects of the present invention: The present invention uses a host or a slave to drag a cooling water pump, and the signal probe group uniformly enters the host of the modular cooling water pump energy efficiency control cabinet group to perform energy efficiency control calculations. A communication interaction network is formed between the modular cooling water pump energy efficiency control cabinets. All modular cooling water pump energy efficiency control cabinet slaves obey the dispatching command of the modular cooling water pump energy efficiency control cabinet host. When the modular cooling water pump energy efficiency control cabinet host and the slave interactive network lose connection, the slave maintains the current operating state, and is still dispatched and commanded by the host after the communication interaction network is restored. The modular cooling water pump energy efficiency control cabinet host obeys the dispatching command of the energy efficiency management and control platform. When the energy efficiency management and control platform loses connection with the modular cooling water pump energy efficiency control cabinet host, it does not affect the decoupled modular high-efficiency central air-conditioning cooling water control system.

[0046] The present invention decouples the entire large-scale water-cooled central air-conditioning system, and the process control modules between the systems are independent of each other, so that the operation of the entire system will not be affected by a single point problem, thereby realizing modular energy-saving control operation of the cooling water system. The decoupled modular high-efficiency central air-conditioning cooling water control system of the present invention is part of a large-scale water-cooled central air-conditioning system, and is suitable for a main pipe type cooling water circulation system or a one-to-one type cooling water circulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1It is the control principle diagram of the central air conditioning system using the BA system in the prior art;

[0048] Figure 2 It is a system diagram of a decoupled high-efficiency central air-conditioning cooling water control system according to an embodiment of the present invention;

[0049] Figure 3 yes Figure 2 Schematic diagram of the master and slave.

[0050] In the figure: 1-cooling tower system group, 2-main unit group, 3-cooling water pump group, 4-main unit main water inlet pipe, 5-main unit main water outlet pipe, 6-main return pipe, 7-flow balancing pipe, 8-flow balancing valve. DETAILED DESCRIPTION

[0051] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] A decoupled high-efficiency central air-conditioning cooling water control system according to an embodiment of the present invention is as follows Figure 1 to Figure 2 As shown, the decoupled high-efficiency central air-conditioning cooling water control system of this embodiment includes a cooling tower system group 1, a main unit group 2, a cooling water pump group 3, a signal probe group, a modular cooling water pump energy efficiency control cabinet group and an energy efficiency management and control platform.

[0053] A main unit water inlet pipe 4 is connected between the total outlet of the cooling water pump group 3 and the total inlet of the main unit group 2, a main unit water outlet pipe 5 is connected between the total outlet of the main unit group 2 and the total inlet of the cooling tower system group 1, a main unit return pipe 6 is connected between the total outlet of the cooling tower system group 1 and the total inlet of the cooling water pump group 3, a flow balance pipe 7 is connected between the main unit water outlet pipe 5 and the main return pipe 6, the flow balance pipe 7 is less than or equal to the diameter of the total return pipe 6 or the main unit water outlet pipe 5, and a flow balance valve 8 is provided on the flow balance pipe 7, and the flow balance valve 8 is an electric valve;

[0054] There are two groups of signal probes. The first group is a pressure sensor and a temperature sensor installed on the main water inlet pipe 4 of the main unit, and the second group is a pressure sensor and a temperature sensor installed on the main water outlet pipe 5 of the main unit.

[0055] The modular cooling water pump energy efficiency control cabinet group includes a host and one or more slaves. The cabinets of the host and each slave are equipped with a power system unit, a speed control system unit and a control system unit. The control system unit sends the calculation results to the speed control system unit. The control system units of the host and the slave are connected through a communication interaction network. The signal end of the flow balancing valve and each signal probe group are uniformly connected to the control system unit of the host. The signal end of each water pump in the cooling water pump group is respectively connected to the control system unit of the host and the slave. Each host or slave is used to drive a water pump. The host is used to obtain and calculate the operating condition information of the cooling water system and allocate and schedule the slave. When the communication network is normal, the host is responsible for allocating and scheduling the operation. When the communication network is abnormal, the slave maintains the current state of operation; the energy efficiency management and control platform is connected to the host of the modular cooling water pump energy efficiency control cabinet group for data exchange.

[0056] The inverter UVW interface in the control cabinet of the host and slave is connected to the water pump UVW interface. The control cabinet calculates and outputs the proportional value of 0~1000 through the controller to adjust the inverter frequency 0~50Hz change, thereby adjusting the operation size of the water pump. The control cabinet calculates and outputs the proportional value of 0~1000 to the controller port corresponding to DC0-10V, and adjusts the inverter frequency 0~50Hz.

[0057] The host and each slave are designed with strong and weak electricity integration, and there are up to 7 slaves. The host and slave use RS485 interface to realize hand-in-hand communication interactive network connection.

[0058] The energy efficiency management and control platform performs visual operations on the cooling water pump energy efficiency control cabinet group. The energy efficiency management and control platform can display, record, and operate the cooling water pump energy efficiency control cabinet group. The energy efficiency management and control platform is connected to the host of the modular cooling water pump energy efficiency control cabinet group through the RS485 interface and the MODBUS-RTU protocol for data exchange.

[0059] The present invention discloses a decoupled high-efficiency central air-conditioning cooling water control method, wherein a signal probe group and a signal end of a flow balancing valve are connected to a host of a modular cooling water pump energy efficiency control cabinet group to perform flow balance calculation and energy efficiency control calculation, each signal probe group is used to collect temperature and pressure values ​​at a corresponding pipeline, and the pressure and temperature measured by a pressure sensor and a temperature sensor installed on a main water outlet pipe of the main unit group are P0 and T1 respectively, and the pressure and temperature measured by a pressure sensor and a temperature sensor installed on a main water outlet pipe of the main unit group are P1 and T0 respectively;

[0060] The flow balancing valve calculation is as follows:

[0061] (1) When the cooling water current T1 is less than the set cooling water minimum return temperature, the cooling water minimum return temperature is set to 26°C, and the flow balance valve begins to enter regulation;

[0062] (2) Collect the month-on-month changes in T1 to determine whether the temperature trend is rising, flat or falling: take a fixed time period of 60 seconds as a cycle, record the current T1 as before T1, and T1 after one cycle as after T1; current ΔT = before T1 - after T1, after n cycles, ΣΔT = ΔT1 + ΔT2 + ΔT3 + ... ΔTn, if ΣΔT is greater than 0, the temperature is on an upward trend, if ΣΔT is equal to 0, the temperature is on a flat trend, if ΣΔT is less than 0, the temperature is on a downward trend;

[0063] (3) When the return water temperature is on the rise, the opening of the flow balancing valve gradually decreases. When the return water temperature changes from the previous month to a flat state, the current valve position is maintained.

[0064] (4) When the return water temperature is decreasing, the opening of the flow balancing valve gradually increases. When the month-on-month change trend of the return water temperature turns to a flat state, the current valve position is maintained;

[0065] The range of the flow balancing valve opening is 0~100%, and the amount of increase or decrease in the flow balancing valve opening per 1s cycle is 0.5% of the maximum opening.

[0066] The energy efficiency control algorithm includes the basic algorithm, the load temperature difference flow correction algorithm and the temperature trend prediction compensation algorithm, which are as follows:

[0067] 1. Basic algorithm:

[0068] The host side is the target:

[0069] Current total traffic ΔPPV 总 = Current host traffic ΔPPV 主机端 ,

[0070] Total flow demand ΔPSV 总 = Host-side traffic demand ΔPSV 主机端 ,

[0071] Among them, the current host traffic ΔPPV 主机端 =P0-P1, host-side traffic demand ΔPSV 主机端 It is a man-made setting;

[0072] 2. Load temperature difference flow correction algorithm:

[0073] (1) Host-side upper and lower limit calculation

[0074] a) Host-side ΔT correction ΔP compensation upper limit = total flow demand ΔPSV 总 × Host-side ΔT correction ΔP compensation upper limit ratio;

[0075] b) Host-side ΔT correction ΔP compensation lower limit = total flow demand ΔPSV 总× Host-side ΔT correction ΔP compensation lower limit ratio;

[0076] The upper limit ratio of ΔT correction ΔP compensation on the host side and the lower limit ratio of ΔT correction ΔP compensation on the host side are both artificially set, and are set to 20% in this embodiment;

[0077] (2) If the flow balancing valve compensation is turned on, the calculation starts, otherwise the compensation value is 0:

[0078] Among them, the host end sampling temperature difference = T1-T0, and the host end standard working condition temperature difference adopts the set standard value;

[0079] a) When the host-side sampled temperature difference is less than the host-side standard operating temperature difference, the host-side ΔT correction ΔP compensation value starts from 0, and when the custom pulse time is up, it is reduced by the set fixed value, and the cycle repeats. When the host-side ΔT correction ΔP compensation value is equal to the host-side ΔT correction ΔP compensation lower limit, the reduction of the set fixed value stops;

[0080] b) When the host-side sampling temperature difference is greater than the host-side standard operating temperature difference, the host-side ΔT correction ΔP compensation value starts from 0, and when the custom pulse time is up, the set fixed value is added, and the cycle repeats. When the host-side ΔT correction ΔP compensation value is greater than or equal to the host-side ΔT correction ΔP compensation upper limit value, the set fixed value is stopped;

[0081] In this embodiment, the custom pulse time is 60s and the fixed value is set to 1Kpa. Flow balancing valve compensation is turned on and the result of operation: the actual flow rate of the cooling water pump is always calculated through the current total flow rate ΔPPV 总 ΔPSV vs. total flow demand 总 By increasing or decreasing the flow balance valve opening to ensure the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , if the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , the cooling water pump maintains its current work unchanged.

[0082] 3. Temperature trend prediction and compensation algorithm:

[0083] When the T2 sampling temperature is less than or equal to the starting temperature, the host end standard operating temperature difference increases by 0.1°C every minute;

[0084] When the T2 sampling temperature is greater than or equal to the end temperature, the host end standard operating temperature difference decreases by 0.1°C every 1 minute;

[0085] The starting temperature and the ending temperature are both set values. In this embodiment, the standard operating temperature difference of the host end is 5°C, the starting temperature is the standard operating temperature of 32°C, and the ending temperature is 37°C.

[0086] The above embodiment is a preferred embodiment of the present invention. In other embodiments of the present invention, the custom pulse time is determined according to the on-site debugging situation. The time can be set to 60s or 120s or other according to the debugging situation. When the custom pulse time reaches the fixed value set by addition and subtraction, it is also determined according to the on-site debugging situation. Adding and subtracting 1KPa is the most basic change amount for this trial compensation. According to the debugging situation, the fixed value set by addition and subtraction can also be 2KPa or other.

[0087] In other embodiments of the present invention, the minimum return water temperature, starting temperature and ending temperature of cooling water are all flexibly set according to needs; the amount and cycle of the flow balance valve opening change can also be flexibly set according to needs.

[0088] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. The scope of the present invention defined by the appended claims includes all equivalent substitutions and changes.

Claims

1. A decoupled high-efficiency central air-conditioning cooling water control system, comprising a cooling tower system group, a main unit group, and a cooling water pump group, wherein a main unit main water inlet pipe is connected between the main outlet of the cooling water pump group and the main inlet of the main unit group, a main unit main water outlet pipe is connected between the main outlet of the main unit group and the main inlet of the cooling tower system group, and a main return water pipe is connected between the main outlet of the cooling tower system group and the main inlet of the cooling water pump group, characterized in that: A flow balance pipe is connected between the main water outlet pipe and the main return pipe of the main unit. The flow balance pipe is smaller than or equal to the diameter of the main return pipe or the main water outlet pipe of the main unit. A flow balance valve is provided on the flow balance pipe. The flow balance valve is an electric valve. The decoupled high-efficiency central air-conditioning cooling water control system also includes a signal probe group, a modular cooling water pump energy efficiency control cabinet group and an energy efficiency management and control platform; There are two groups of signal probes. The first group is a pressure sensor and a temperature sensor installed on the main water inlet pipe of the main unit. The second group is a pressure sensor and a temperature sensor installed on the main water outlet pipe of the main unit. The modular cooling water pump energy efficiency control cabinet group includes a host and more than one slave. The cabinets of the host and each slave are equipped with a power system unit, a speed control system unit and a control system unit. The control system unit sends the calculation results to the speed control system unit. The control system units of the host and the slave are connected through a communication interaction network. The signal end of the flow balancing valve and each signal probe group are uniformly connected to the control system unit of the host. The signal end of each water pump in the cooling water pump group is respectively connected to the control system unit of the host and the slave. Each host or slave is used to drive a water pump. The host is used to obtain and calculate the operating condition information of the cooling water system and allocate and dispatch the slave. When the communication network is normal, the host is responsible for allocating and dispatching operations. When the communication network is abnormal, the slave maintains the current state of operation. The energy efficiency management and control platform is connected to the host of the modular cooling water pump energy efficiency control cabinet group for data exchange; Flow balancing valve compensation opening operation result: The actual flow rate of the cooling water pump is always measured by the current total flow rate ΔPPV 总 ΔPSV vs. total flow demand 总 By increasing or decreasing the flow balance valve opening to ensure the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , if the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , the cooling water pump maintains its current work unchanged.

2. The decoupled high-efficiency central air-conditioning cooling water control system according to claim 1 is characterized in that: The host and each slave are designed with integrated strong and weak electricity, and there are up to 7 slaves.

3. The decoupled high-efficiency central air-conditioning cooling water control system according to claim 1 is characterized in that: The host and slave use RS485 interface to realize hand-in-hand communication interactive network connection.

4. A decoupled high-efficiency central air-conditioning cooling water control method, characterized in that: Connect the signal probe group and the signal end of the flow balance valve to the host of the modular cooling water pump energy efficiency control cabinet group to perform flow balance calculation and energy efficiency control calculation. Each signal probe group is used to collect the temperature and pressure values ​​at the corresponding pipeline. The pressure and temperature measured by the pressure sensor and temperature sensor installed on the main water outlet pipe of the main unit are P0 and T1 respectively. The pressure and temperature measured by the pressure sensor and temperature sensor installed on the main water outlet pipe of the main unit are P1 and T0 respectively. The flow balance calculation is as follows: (1) When the cooling water current T1 is lower than the set minimum cooling water return temperature, the flow balance valve begins to adjust; (2) Collect the month-on-month changes in T1 to determine whether the temperature trend is rising, flat or falling: take a fixed time period as a cycle, record the current T1 as before T1, and T1 after one cycle as after T1; current ΔT = before T1 - after T1, after n cycles, ΣΔT = ΔT1 + ΔT2 + ΔT3 + ... ΔTn, if ΣΔT is greater than 0, the temperature is on an upward trend, if ΣΔT is equal to 0, the temperature is on a flat trend, if ΣΔT is less than 0, the temperature is on a downward trend; (3) When the return water temperature is on the rise, the opening of the flow balancing valve gradually decreases. When the return water temperature changes from the previous month to a flat state, the current valve position is maintained. (4) When the return water temperature is decreasing, the opening of the flow balancing valve gradually increases. When the month-on-month change trend of the return water temperature turns to a flat state, the current valve position is maintained; Energy efficiency control calculation includes basic algorithm and load temperature difference flow correction algorithm, specifically:

1. Basic algorithm: The host side is the target: Current total traffic ΔPPV 总 = Current host traffic ΔPPV 主机端 , Total flow demand ΔPSV 总 = Host-side traffic demand ΔPSV 主机端 , Among them, the current host traffic ΔPPV 主机端 =P0-P1, host-side traffic demand ΔPSV 主机端 It is a man-made setting; 2. Load temperature difference flow correction algorithm: (1) Host-side upper and lower limit calculation a) Host-side ΔT correction ΔP compensation upper limit = total flow demand ΔPSV 总 × Host-side ΔT correction ΔP compensation upper limit ratio; b) Host-side ΔT correction ΔP compensation lower limit = total flow demand ΔPSV 总 × Host-side ΔT correction ΔP compensation lower limit ratio; The upper limit ratio of ΔT correction ΔP compensation on the host side and the lower limit ratio of ΔT correction ΔP compensation on the host side are both set manually; (2) If the flow balancing valve compensation is turned on, the calculation starts, otherwise the compensation value is 0: Among them, the host end sampling temperature difference = T1-T0, and the host end standard working condition temperature difference adopts the set standard value; a) When the host-side sampled temperature difference is less than the host-side standard operating temperature difference, the host-side ΔT correction ΔP compensation value starts from 0, and when the custom pulse time is up, it is reduced by the set fixed value, and the cycle repeats. When the host-side ΔT correction ΔP compensation value is equal to the host-side ΔT correction ΔP compensation lower limit, the reduction of the set fixed value stops; b) When the host-side sampling temperature difference is greater than the host-side standard operating temperature difference, the host-side ΔT correction ΔP compensation value starts from 0, and when the custom pulse time is up, the set fixed value is added, and the cycle repeats. When the host-side ΔT correction ΔP compensation value is greater than or equal to the host-side ΔT correction ΔP compensation upper limit value, the set fixed value is stopped; Flow balancing valve compensation opening operation result: The actual flow rate of the cooling water pump is always measured by the current total flow rate ΔPPV 总 ΔPSV vs. total flow demand 总 By increasing or decreasing the flow balance valve opening to ensure the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , if the current total flow ΔPPV 总 = Total flow demand ΔPSV 总 , the cooling water pump maintains its current work unchanged.

5. The decoupled high-efficiency central air-conditioning cooling water control method according to claim 4 is characterized in that: The energy efficiency control calculation also includes a temperature trend prediction and compensation algorithm, specifically: When the T2 sampling temperature is less than or equal to the starting temperature, the host end standard operating temperature difference increases by 0.1°C every minute; When the T2 sampling temperature is greater than or equal to the end temperature, the host end standard operating temperature difference decreases by 0.1°C every 1 minute; The starting temperature and ending temperature are both set values.

6. The decoupled high-efficiency central air-conditioning cooling water control method according to claim 5 is characterized in that: The standard operating temperature difference of the host end is 5°C, the starting temperature is the standard operating temperature of 32°C, and the ending temperature is 37°C.

7. The decoupled high-efficiency central air-conditioning cooling water control method according to claim 4 is characterized in that: The range of the flow balancing valve opening is 0~100%, and the amount of increase or decrease in the flow balancing valve opening per 1s cycle is 0.5% of the maximum opening.

8. The decoupled high-efficiency central air-conditioning cooling water control method according to claim 4 is characterized in that: The minimum return temperature of cooling water is set at 26°C.

9. The decoupled high-efficiency central air-conditioning cooling water control method according to claim 4 is characterized in that: When collecting the month-on-month change of T1, the fixed time period used is 60 seconds.

10. The decoupled high-efficiency central air-conditioning cooling water control method according to claim 4, characterized in that: The custom pulse time is 60-120s, and the set fixed value is 1Kpa.

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