A ventilation and air conditioning control method, system, device and medium

Abstract

The present invention proposes a ventilation and air-conditioning control method, system, equipment and medium, which relate to the field of automation methods, and specifically include: obtaining environmental parameters, state parameters and equipment operation parameters collected in real time; based on the above parameters, according to the changing trend of the temperature in the station, predicting and controlling the outlet water temperature of the chiller, the operating frequency of the supply fan and the return fan, and assisting in following the control of the chilled water pump, the cooling water pump and the cooling tower fan, so as to control the operation of the ventilation and air-conditioning system with the highest efficiency and the lowest energy consumption as the goal; the present invention is applied to the field of ventilation and air-conditioning control of subway stations, and can effectively improve the control response of various components of the ventilation and air-conditioning system, and effectively reduce the operating energy consumption of the system.

Description

Technical Field

[0001] The present invention belongs to the field of automation methods, and in particular relates to a ventilation and air-conditioning control method, system, equipment and medium. Background Art

[0002] Subway stations are places with dense and highly mobile flow of people. The heat load in the station changes greatly within a day, requiring the subway station ventilation and air-conditioning system to be able to adjust and control various components in real time according to the changes in the heat load in the station.

[0003] At present, the operation control of each component of the ventilation and air-conditioning system of subway stations mostly adopts feedback control methods. The components of the water system and wind system of ventilation and air-conditioning are controlled by closed-loop feedback according to their corresponding control targets to achieve the operation control of each component. The existing ventilation and air-conditioning systems mostly adopt PID feedback control algorithms. Each component obtains the control parameters for the next regulation according to the current operating status and the corresponding control target, such as the outlet water temperature of the chiller, the fan frequency and the pump frequency. Although this method has a certain adaptive adjustment capability, it does not have the ability of predictive regulation because it uses the current status to determine the next control quantity, which makes the control effect lagging, especially the core component of the ventilation and air-conditioning system, the chiller. Due to the working characteristics of the equipment itself, the response speed of the equipment to the control command is slow. In addition, due to the large area of ​​the subway station, the thermal inertia of the temperature adjustment in the station is large, which increases the difficulty of real-time regulation of the ventilation and air-conditioning system, resulting in the inability to match the operating status of each ventilation and air-conditioning component with the heat load demand in real time. In order to ensure that the temperature inside the station meets the requirements, the method of increasing the cooling capacity of ventilation and air conditioning is currently generally adopted. On the one hand, this causes the temperature inside the station to be relatively low, affecting the comfort of passengers in the station; on the other hand, it also brings about the problem of high energy consumption of the entire system.

[0004] Therefore, the existing ventilation and air-conditioning control solutions have the problems of poor real-time performance, energy waste caused by easy parameter overshoot, and are prone to low or high temperatures causing discomfort to passengers. Summary of the invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a ventilation and air-conditioning control method, system, equipment and medium, which are applied to the field of ventilation and air-conditioning control in subway stations, and can effectively improve the control response of various components of the ventilation and air-conditioning system and effectively reduce the operating energy consumption of the system.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of the present invention provides a method for controlling ventilation and air conditioning.

[0008] A method for controlling ventilation and air conditioning, comprising:

[0009] Obtain real-time collected environmental parameters, status parameters and equipment operation parameters;

[0010] Based on the above parameters, according to the temperature change trend in the station, the outlet water temperature of the chiller, the operating frequency of the supply fan and the return fan are predicted and controlled, and the chilled water pump, cooling water pump and cooling tower fan are assisted in follow-up control, so as to achieve the highest efficiency and lowest energy consumption of the entire ventilation and air-conditioning system.

[0011] Among them, the outlet water temperature of the chiller adopts a method that combines predictive control and real-time feedback correction. The outlet water temperature of the chiller is predicted in advance according to the changing trend of the temperature in the station, which is used to control the operating status of the chiller; the outlet water temperature of the chiller is corrected in real time through the error between the actual station temperature and the predicted station temperature.

[0012] Furthermore, the environmental parameters include indoor and outdoor temperature and humidity;

[0013] The state parameters include temperature, pressure and flow rate of various parts of the ventilation and air conditioning system;

[0014] The equipment operating parameters include refrigeration machine operating parameters, refrigeration pump cooling pump frequency, cooling tower fan frequency, and supply fan return fan frequency.

[0015] Furthermore, the specific steps of predicting and controlling the outlet water temperature of the chiller are as follows:

[0016] According to the chiller response curve and the predicted control parameters, the station temperature is predicted;

[0017] According to the predicted value of the station temperature, the station temperature control target and the fluctuation of the outlet water temperature, the predicted value of the outlet water temperature of the chiller is determined to control the operating status of the chiller.

[0018] Furthermore, the specific steps of predicting and controlling the operating frequencies of the supply fan and the return fan are as follows:

[0019] Calculate the cooling capacity of the chiller based on the chilled water flow rate and supply and return water temperatures;

[0020] Based on the cooling capacity, combined with the target station temperature and predicted temperature, the heat load is predicted;

[0021] Based on the heat load, the operating frequency of the supply fan and the return fan is determined for the control of the supply fan and the return fan.

[0022] Furthermore, the follow-up control of the chilled water pump adopts a closed-loop control algorithm, takes the pressure at the most unfavorable end of the entire system to meet the requirements as the control target, monitors the pressure at the most unfavorable end of the entire system in real time, and adjusts the operating frequency of the chilled water pump through feedback control.

[0023] Furthermore, the following control of the cooling water pump takes ensuring that the condenser is at a constant temperature as a control target, and a closed-loop control algorithm is used to control the frequency of the cooling water pump.

[0024] Furthermore, the following control of the cooling tower fan obtains the target value of the cooling tower outlet water temperature according to the outdoor temperature and humidity. For the fan controlled by switch, the deviation between the actual cooling tower outlet water temperature and the target temperature is compared, and the cooling tower outlet water temperature is controlled in real time through the switch control of the fan. For the cooling tower fan controlled by frequency conversion, a closed-loop control algorithm is used to take the target value of the cooling tower outlet water temperature as the control target, and the fan frequency is adjusted in real time to ensure that the actual outlet water temperature is maintained near the target value.

[0025] A second aspect of the present invention provides a ventilation and air-conditioning control system.

[0026] A ventilation and air conditioning control system, comprising an acquisition module and a control module:

[0027] The acquisition module is configured to: acquire environmental parameters, state parameters and equipment operation parameters collected in real time;

[0028] The control module is configured to: based on the above parameters and according to the change trend of the temperature in the station, predict and control the outlet water temperature of the chiller, the operating frequency of the supply fan and the return fan, and assist in following the chilled water pump, the cooling water pump and the cooling tower fan, so as to control the operation of the entire ventilation and air conditioning system with the highest efficiency and the lowest energy consumption;

[0029] Among them, the outlet water temperature of the chiller adopts a method that combines predictive control and real-time feedback correction. The outlet water temperature of the chiller is predicted in advance according to the changing trend of the temperature in the station, which is used to control the operating status of the chiller; the outlet water temperature of the chiller is corrected in real time through the error between the actual station temperature and the predicted station temperature.

[0030] A third aspect of the present invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps of a ventilation and air conditioning control method as described in the first aspect of the present invention.

[0031] The fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in a ventilation and air conditioning control method as described in the first aspect of the present invention are implemented.

[0032] One or more of the above technical solutions have the following beneficial effects:

[0033] 1) The present invention proposes an optimization control algorithm for the ventilation and air-conditioning system of a subway station. The outlet water temperature of the chiller is controlled through predictive control and real-time feedback correction. Combined with the predicted temperature inside the station, the supply and return fan frequencies are adjusted in advance. By predictive control of the above-mentioned key components, the responsiveness of the system control can be effectively improved.

[0034] 2) By adopting the predictive control algorithm, the cooling capacity generated by each ventilation and air-conditioning system can be more closely matched to the required heat load. On the one hand, it can reduce the energy waste caused by overshoot of the control parameters and reduce the energy consumption of the system. On the other hand, the temperature in the station is closer to the target value, and there will be no problem of passengers feeling uncomfortable due to low or high temperature.

[0035] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0037] Figure 1 This is a flow chart of the method of the first embodiment.

[0038] Figure 2 This is a main structural diagram of the subway station ventilation and air-conditioning system of the first embodiment.

[0039] Figure 3 Schematic diagram of the chiller outlet water temperature prediction and correction algorithm of the first embodiment.

[0040] Figure 4 Schematic diagram of the frequency prediction control algorithm of the supply fan and return fan of the first embodiment.

[0041] FIG. 5( a ) is a diagram of a chilled water pump frequency control algorithm according to the first embodiment.

[0042] FIG5( b ) is a diagram of the cooling water pump frequency control algorithm of the first embodiment.

[0043] FIG. 6( a ) is a diagram showing the control algorithm of the switch-controlled cooling tower fan according to the first embodiment.

[0044] FIG. 6( b ) is a control algorithm diagram of the variable frequency controlled cooling tower fan of the first embodiment. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] At present, the ventilation and air conditioning of subway stations mostly use the PID feedback method to individually control each component. This method has a certain automatic adjustment capability. This control method determines the control parameters based on the current state and does not have the ability of predictive control. Since the adjustment of the operating state of the chiller in the ventilation and air conditioning system has a large lag, and the ambient temperature adjustment in the subway station has a large thermal inertia, the traditional PID control method has a lag, resulting in the inability to match the operating state of each ventilation and air conditioning component with the heat load demand in real time. In order to ensure that the temperature in the station meets the requirements, the method of increasing the cooling capacity of the ventilation and air conditioning is currently generally used. This, on the one hand, leads to a low temperature in the station, affecting the comfort of passengers in the station; on the other hand, it also brings about the problem of high energy consumption of the entire system.

[0048] In view of this, the present invention proposes a ventilation and air conditioning system control method based on predictive control and real-time feedback correction. The method predicts the control value of the outlet water temperature of the chiller in advance according to the change trend of the temperature in the station, and controls the operating state of the chiller; at the same time, through the error between the actual temperature in the station and the predicted value, the control parameter (i.e., the outlet water temperature of the chiller) is corrected in real time feedback to improve the control accuracy; according to the trend of temperature change in the station, the operating frequency of the supply fan and return fan of the ventilation and air conditioning system is pre-controlled to further improve the responsiveness of the system; the chilled water pump, cooling water pump and cooling tower fan of the ventilation and air conditioning have a fast adjustment speed, and these three components adopt follow-up control to ensure the optimal working state of the chiller and perform closed-loop control. The method proposed by the present invention can effectively improve the responsiveness of the system; in addition, by optimizing the control of various components of the ventilation and air conditioning, the efficient and energy-saving operation of the entire system can be achieved.

[0049] Embodiment 1

[0050] In one embodiment of the present disclosure, a method for controlling ventilation and air conditioning is provided. Figure 1 As shown, the following steps are included:

[0051] Step S1: Acquire environmental parameters, state parameters and equipment operation parameters collected in real time;

[0052] Step S2: Based on the above parameters and according to the change trend of the temperature in the station, the outlet water temperature of the chiller, the operating frequency of the supply fan and the return fan are predicted and controlled, and the chilled water pump, the cooling water pump and the cooling tower fan are assisted in follow-up control, so as to achieve the highest efficiency and the lowest energy consumption of the entire ventilation and air-conditioning system and perform operation control;

[0053] Among them, the outlet water temperature of the chiller adopts a method that combines predictive control and real-time feedback correction. The outlet water temperature of the chiller is predicted in advance according to the changing trend of the temperature in the station, which is used to control the operating status of the chiller; the outlet water temperature of the chiller is corrected in real time through the error between the actual station temperature and the predicted station temperature.

[0054] Furthermore, the environmental parameters include indoor and outdoor temperature and humidity;

[0055] The state parameters include temperature, pressure and flow rate of various parts of the ventilation and air conditioning system;

[0056] The equipment operating parameters include refrigeration machine operating parameters, refrigeration pump cooling pump frequency, cooling tower fan frequency, and supply fan return fan frequency.

[0057] Furthermore, the specific steps of predicting and controlling the outlet water temperature of the chiller are as follows:

[0058] According to the chiller response curve and the predicted control parameters, the station temperature is predicted;

[0059] According to the predicted value of the station temperature, the station temperature control target and the fluctuation of the outlet water temperature, the predicted value of the outlet water temperature of the chiller is determined to control the operating status of the chiller.

[0060] Furthermore, the specific steps of predicting and controlling the operating frequencies of the supply fan and the return fan are as follows:

[0061] Calculate the cooling capacity of the chiller based on the chilled water flow rate and supply and return water temperatures;

[0062] Based on the cooling capacity, combined with the target station temperature and predicted temperature, the heat load is predicted;

[0063] Based on the heat load, the operating frequency of the supply fan and the return fan is determined for the control of the supply fan and the return fan.

[0064] Furthermore, the follow-up control of the chilled water pump adopts a closed-loop control algorithm, takes the pressure at the most unfavorable end of the entire system to meet the requirements as the control target, monitors the pressure at the most unfavorable end of the entire system in real time, and adjusts the operating frequency of the chilled water pump through feedback control.

[0065] Furthermore, the following control of the cooling water pump takes ensuring that the condenser is at a constant temperature as a control target, and a closed-loop control algorithm is used to control the frequency of the cooling water pump.

[0066] Furthermore, the following control of the cooling tower fan obtains the target value of the cooling tower outlet water temperature according to the outdoor temperature and humidity. For the fan controlled by switch, the deviation between the actual cooling tower outlet water temperature and the target temperature is compared, and the cooling tower outlet water temperature is controlled in real time through the switch control of the fan. For the cooling tower fan controlled by frequency conversion, a closed-loop control algorithm is used to take the target value of the cooling tower outlet water temperature as the control target, and the fan frequency is adjusted in real time to ensure that the actual outlet water temperature is maintained near the target value.

[0067] The following describes in detail the implementation process of a ventilation and air conditioning control method of this embodiment from two aspects: component composition and control architecture of the ventilation and air conditioning system.

[0068] 1. Components of ventilation and air conditioning system

[0069] like Figure 2 As shown, the subway station ventilation and air-conditioning system consists of two parts: a chilled water cycle and a cooling water cycle. The chilled water cycle is used to generate the cooling capacity required for temperature regulation in the subway station, including main components such as chillers, chilled water pumps and combined air conditioners; the cooling water cycle is mainly used to cool the chillers, including main components such as cooling water pumps and cooling towers.

[0070] The chiller is the core system of the entire ventilation and air conditioning system. It generates cooling capacity through a vapor compression refrigeration cycle. The liquid refrigerant flows into the evaporator through the throttling element. Due to the reduction in pressure, it vaporizes. The vaporization process absorbs the heat of the chilled water system to achieve the purpose of refrigeration. After the liquid vaporizes, it becomes dry saturated vapor, flows into the suction port of the compressor, is sucked in by the compressor and compressed into high-pressure gas. In this process, the compressor needs to consume mechanical energy and convert it into heat energy, which causes the temperature of the refrigerant vapor to rise and the refrigerant vapor is superheated. The high-pressure refrigerant vapor discharged from the refrigeration compressor releases heat in the condenser and transfers the heat to the cooling water system. At the same time, the refrigerant vapor gradually condenses into liquid. The refrigerant liquid flowing out of the condenser is decompressed to the evaporation pressure through the expansion valve, etc. The temperature of the refrigerant after throttling also drops to the evaporation temperature, and some flash vapor is generated. The throttled air flow mixture enters the evaporator and repeats the above evaporation process.

[0071] The cooling capacity generated by the chiller is used to cool the water in the chilled water cycle, and the cooled water is sent to the fan coil of the combined air conditioner through the chilled water pump. The fan in the combined air conditioner blows the hot air in the subway station to the fan coil and sends the cooled air to the space inside the station, thereby achieving the purpose of regulating the temperature of the space inside the station through heat transfer.

[0072] When the chiller generates cooling capacity, it releases heat at the condenser, which is then transferred to the cooling water system. The cooling water pump of the cooling water system sends the heated water to the cooling tower. When the water temperature is low, it is cooled by natural wind. When the water temperature is high, the cooling tower fan is turned on to reduce the temperature of the cooling water by forced air circulation.

[0073] 2. Control Architecture

[0074] like Figure 2 As shown in the figure, ventilation and air conditioning control includes four parts in terms of overall architecture: data input, algorithm analysis, control output and data display.

[0075] 1. Data input

[0076] Mainly through the installation of various sensors to obtain indoor and outdoor temperature and humidity and other environmental parameters, the temperature of each part of the whole system, pressure and flow and other state parameters, the equipment operation parameters of each component of the system, specifically:

[0077] The environmental parameters include indoor and outdoor temperature and humidity;

[0078] The state parameters include temperature, pressure and flow rate of various parts of the ventilation and air conditioning system;

[0079] The equipment operating parameters include refrigeration machine operating parameters, refrigeration pump and cooling pump frequencies, cooling tower fan frequencies, supply fan and return fan frequencies.

[0080] 2. Algorithm Analysis

[0081] According to the input data, the operation control is mainly carried out for the main components of the ventilation and air-conditioning system (water chiller, chilled water pump, cooling water pump, blower, return blower, cooling tower blower): predictive control of the outlet water temperature of the water chiller, the frequency of the blower and return blower; feedback control of the chilled water pump, the cooling water pump on the cooling side and the cooling tower blower; according to the collected data from each sensor, the operation status of the components is monitored in real time, and alarm signals are issued in advance for components with potential faults, specifically:

[0082] 1) Chiller outlet water temperature control algorithm

[0083] Figure 3 It is the schematic diagram of the chiller control algorithm, as shown in Figure 3As shown in the figure, the response characteristics of the chiller are tested experimentally, and the chiller response curve is constructed as the prediction benchmark for the chiller outlet water temperature regulation; in each control cycle, the station temperature at the future time starting from the current control cycle is predicted by combining the response characteristics of the chiller and the chiller outlet water temperature parameters predicted in the previous control cycle. According to the predicted station temperature and the station temperature control target, combined with the fluctuation of the chiller outlet water temperature, the chiller control parameters corresponding to the current control cycle are obtained and used to control the operation of the chiller; in order to ensure the effectiveness of the chiller outlet water temperature, the measured station temperature is compared with the predicted station temperature to achieve real-time feedback correction of the predicted outlet water temperature.

[0084] Specifically, for chillers, the main task is predictive control of the outlet water temperature. When the heat load exceeds the set load rate of a single chiller, it is necessary to add more units to increase the number of chillers in operation. Conversely, when the heat load decreases, it is necessary to reduce the number of units.

[0085] The chiller includes multiple components such as an evaporator, a condenser, a compressor and an expansion valve. Its working characteristics determine that the adjustment of the system itself has a lag. In addition, the thermal inertia of the temperature adjustment in the station space is large, and the chiller needs to be predictively controlled to improve the responsiveness of the entire system. To this end, this embodiment proposes a control algorithm that combines predictive control and feedback correction, and obtains a predicted value of the chiller outlet water temperature according to the changing trend of the temperature in the station, and implements control. Taking into account the difference between the predicted value and the actual output, the outlet water temperature is corrected in real time through real-time feedback correction to improve the control accuracy of the outlet water temperature.

[0086] In the predictive control stage, in order to improve the prediction accuracy, it is necessary to first test the response characteristics of the chiller. The specific implementation method is as follows:

[0087] When the temperature in the station is stable, set a lower outlet water temperature value for the chiller. As the outlet water temperature decreases, the temperature in the station will show a downward trend. Test the temperature change curve in the station. Set the sampling time (in N is the number of sampling points, T is the sampling period), measuring the temperature inside the station at each sampling moment, and using Indicates that after a period of time, the temperature in the station tends to be stable, using a finite set Characterize the response characteristics of the chiller.

[0088] The response characteristics obtained by the above method can be considered as the temperature change curve of the station when the fixed control parameters are applied to the chiller; assuming that the current moment is k Moment, you can get the future N The predicted value of the station temperature at a certain moment is calculated as follows:

[0089]

[0090] in, Indicated in k Always k + i The predicted temperature value in the station at the time, express k The chiller outlet water temperature control increment at the moment.

[0091] In the actual control process, the outlet water temperature of the chiller is in a dynamic adjustment process. M Different chiller outlet water temperatures Under this effect, the output value of the station temperature at each moment in the future is:

[0092]

[0093] System k Always looking to the future P The output prediction function at each moment can be expressed as:

[0094]

[0095] in, A is the response characteristic matrix, M ≤ P ≤ N , specifically expressed as:

[0096]

[0097] After obtaining the prediction results of the station temperature, it is necessary to predict the control increment of the chiller outlet water temperature , assuming that the current k time, predict the M The predicted chiller outlet water temperature can be controlled in the future under the control of each predicted outlet water temperature. P The station temperature at the moment is as close to the target value as possible ; In addition, to prevent the chiller outlet water temperature from being controlled by the predicted value of the increment The fluctuation is too large, increase the constraint value, and get k Chiller outlet water temperature control increment at any time The method of determining is as follows:

[0098]

[0099] in, represents the weight of the change in the temperature tracking error within the station, Represents the weight of the change in the control effect on the chiller outlet water temperature.

[0100] Combining the above prediction function, the vector form of rolling optimization is:

[0101]

[0102] in:

[0103] ,

[0104] ,

[0105] .

[0106] In order to ask The minimum value that satisfies the above formula is Take the derivative and set it equal to 0, and only take By acting on the object with the first element of , we can get the predicted value of the chiller outlet water temperature control increment:

[0107]

[0108] in, .

[0109] The above method can be used to obtain the predicted results of the station temperature. In order to ensure the effectiveness of the outlet water temperature control, it is also necessary to perform real-time feedback correction on the predicted temperature according to the actual temperature in the station. The correction method is as follows:

[0110] exist k At time t, the optimal control increment of the chiller outlet water temperature is obtained according to the prediction algorithm , based on which, we can get the future N The temperature value of the station predicted by the model at the moment. When the next moment arrives, take the first element of the temperature value of the station predicted output at the previous moment, which is the temperature value of the station at the current moment. ) and the actual station temperature value at the current moment By comparison, the error of the predicted temperature value in the station is obtained. :

[0111] )

[0112] The weighted error sequence is obtained by weighting the error and used to calibrate the prediction model. The calculation expression is as follows:

[0113]

[0114] in, Indicated in Predicted at all times The temperature value in the station at the moment; Indicated in k +1 is the value after correcting the above predicted values.

[0115] The corrected predicted value of the station temperature is obtained through the above feedback correction method. When the next control cycle comes, the above process can be repeated to realize the predicted control and real-time feedback correction of the station temperature. The purpose of feedback correction of the station temperature is to correct the predicted chiller outlet water temperature to ensure the validity of the predicted value. Since the outlet water temperature of the chiller is adjusted in advance, it can adapt to the changing trend of the station temperature more quickly and meet the needs of real-time temperature control in the station.

[0116] 2) Supply fan and return fan control algorithm

[0117] Figure 4 The schematic diagram of the predictive control algorithm for the supply fan and return fan is shown in Figure 4 As shown, the cooling capacity output by the chiller is calculated based on the chilled water flow rate and the supply and return water temperatures; the heat load can be predicted based on the target station temperature and the predicted station temperature deviation, combined with the cooling capacity of the chiller; the lookup table of the supply and return fan frequencies is obtained based on the variation range of the station heat load; in the actual operation control of the supply and return fans, the heat load is predicted based on the predicted station temperature, and the supply and return fan frequencies are determined by the predicted heat load lookup table, thereby realizing predictive control of the fan frequency.

[0118] Specifically, the frequency control of the supply fan and the return fan adopts a segmented table lookup method. Taking into account the large thermal inertia during temperature adjustment in the station, the fan frequency is predictively controlled to improve the responsiveness of the entire system. The heat load is predicted based on various monitoring parameters in the station, and the frequency of the supply fan and the return fan is obtained by looking up the table based on the predicted heat load.

[0119] The heat load of the subway station space includes: the heat transferred from the ambient temperature to the subway station, the heat generated by the people in the station, the heat generated by the operation of the subway vehicles, and the heat generated by the equipment in the station; the ventilation and air-conditioning system generates cooling capacity and balances it with the heat load, resulting in changes in the temperature in the station; thus, the relationship between heat load and cooling capacity can be obtained as shown below:

[0120]

[0121] in, is the heat load, The cooling capacity output by the chiller to the subway station. is the target value of the station temperature, is the actual station temperature.

[0122] The low-temperature chilled water produced by the chiller is transferred to the fan coil unit through the chilled water pump. Under the heating effect of the hot air in the station, the temperature of the chilled water rises. The cooling capacity output by the chiller can be calculated as follows:

[0123]

[0124] in, is the specific heat capacity of water, is the chilled water flow rate, The high-temperature water that flows through the fan coil and returns to the chiller. Low temperature water is delivered to the fan coil unit of the chiller.

[0125] According to the above two formulas, the calculation formula of heat load can be obtained:

[0126]

[0127] In the chiller outlet water temperature prediction control algorithm, the station temperature can be predicted. The predicted value is substituted into the above formula, and then combined with the chilled water flow rate and the supply and return water temperatures of the chilled water, the predicted heat load can be obtained; according to the variation range of the heat load in the station, the lookup table of the supply fan and return fan frequency is obtained; in the actual operation control of the supply fan and return fan, the heat load is predicted according to the predicted station temperature, and the supply fan and return fan frequencies are determined by the predicted heat load lookup table to realize the prediction control of the fan frequency.

[0128] 3) Chilled water pump and cooling water pump control algorithm

[0129] In ventilation and air conditioning systems, chilled water pumps are used to deliver low-temperature water produced by the chiller to the fan coil. Under the action of water pressure, the chilled water returns to the chiller for circulation; the main function of the chilled water pump is to maintain the normal flow of the chilled water cycle.

[0130] FIG5 (a) is a schematic diagram of a chilled water pump control algorithm. As shown in FIG5 (a), the control of the chilled water pump in this embodiment is mainly used to ensure that the pressure at the most unfavorable end is in a normal state, to monitor the pressure at the most unfavorable end of the entire system in real time, and to use a closed-loop feedback control algorithm to ensure that the pressure at the most unfavorable end meets the use requirements, thereby controlling the minimum operating frequency of the chilled water pump. This control method ensures the normal operation of the chilled water cycle, while reducing system energy consumption by using a lower pump frequency.

[0131] The closed-loop feedback control algorithm here adopts the existing PID algorithm. Its principle is that there is a control target value and an actual value of the current feedback. According to the target value and the actual value, the control result is obtained through calculations such as proportional, integral, and differential coefficients. I will not go into details here.

[0132] Figure 5 (b) is a schematic diagram of the cooling water pump control algorithm. As shown in Figure 5 (b), the cooling water pump is used to control the cooling water circulation. The cooling water is transported to the condenser of the chiller through the water pressure generated by the cooling water pump to take away the heat generated by the chiller. The temperature of the cooling water rises after passing through the chiller, and the cooling water pump transports the heated cooling water to the cooling tower for cooling. The operating frequency of the cooling water pump is used to ensure that the condenser is at a constant temperature as the control target. According to the factory manual of the chiller, the optimal operating temperature range of the condenser is determined. A closed-loop feedback control algorithm is used to control the frequency of the cooling water pump with the optimal operating temperature range as the target.

[0133] 4) Cooling tower fan control algorithm

[0134] The cooling tower fan is mainly used to control the outlet water temperature of the cooling tower. The target value of the outlet water temperature of the cooling tower is obtained according to the outdoor temperature and humidity. The cooling water pump transports the heated cooling water to the cooling tower, and cools it down through natural cooling or forced heat exchange by the fan. The cooling tower fan can be controlled by switch or frequency conversion, which is determined according to the operating characteristics of the fan. The target of fan control is the outlet water temperature of the cooling tower. The outlet water temperature of the cooling tower is obtained according to the outdoor temperature and humidity. The specific calculation formula is as follows:

[0135]

[0136] in, T is the outdoor temperature, is the outdoor relative humidity, atan is the inverse tangent function.

[0137] According to the above formula, combined with the measured outdoor temperature and humidity, the target cooling tower outlet water temperature can be obtained; for the fan controlled by switch, the corresponding control algorithm is as follows:

[0138] Figure 6 (a) is a diagram of the control algorithm of the switch-controlled cooling tower fan. As shown in Figure 6 (a), when the measured cooling tower outlet water temperature is 2 degrees higher than the target value, the fan is controlled to run and the cooling tower outlet water temperature is reduced by forced ventilation; when the measured cooling tower outlet water temperature is 2 degrees lower than the target value, the fan is stopped and the cooling tower outlet water temperature is controlled in real time through switch control.

[0139] Figure 6 (b) is a control algorithm diagram of the variable frequency controlled cooling tower fan. As shown in Figure 6 (b), for the cooling tower fan using variable frequency control, a closed-loop control algorithm is used to adjust the fan frequency in real time with the target cooling tower outlet water temperature as the control target to ensure that the actual outlet water temperature is maintained near the target value.

[0140] 3. Control output

[0141] Mainly for the operation control of the main components of the ventilation and air conditioning system (chiller, chilled water pump, cooling water pump, supply fan, return fan, cooling tower fan):

[0142] 1) For chillers, the main task is to predict and control the outlet water temperature. When the heat load exceeds the set load rate of a single chiller, it is necessary to add more chillers to increase the number of chillers in operation. Conversely, when the heat load decreases, it is necessary to reduce the number of chillers.

[0143] 2) The chilled water pump is used to deliver the low-temperature water produced by the chiller to the air conditioner terminal. Each chiller corresponds to a chilled water pump. The main control parameter of the chilled water pump is the operating frequency, which is used to maintain the pressure of the chilled water circulation to meet the requirements; in addition, when the chiller is added or reduced, the corresponding chilled water pump also needs to be turned on or off.

[0144] 3) The cooling water pump is used to deliver the high-temperature water generated by the chiller group to the cooling tower. In order to ensure the efficiency of the chiller, the cooling water pump performs closed-loop control of the operating frequency with the goal of ensuring a constant condenser temperature of the chiller; the control parameter is the frequency of the cooling water pump;

[0145] 4) The cooling tower fan is used to cool the high-temperature water transmitted by the cooling water pump. The target value of the cooling tower outlet water temperature is obtained according to the outdoor temperature and humidity. For the fan controlled by switch, the deviation between the measured cooling tower outlet water temperature and the target temperature is compared. The cooling tower outlet water temperature is controlled in real time through the switch control of the fan. For the cooling tower fan controlled by frequency conversion, a closed-loop control algorithm is used to take the target value of the cooling tower outlet water temperature as the control target, and the fan frequency is adjusted in real time to ensure that the actual outlet water temperature is maintained near the target value.

[0146] In addition, in order to ensure the normal delivery of cooling water circulation, the number of cooling water pumps in operation needs to be controlled.

[0147] 5) The supply fan at the end of the air conditioner sends the hot air in the subway station to the fan coil for cooling, and the return fan is used to circulate the air in the station. The main control parameters of the supply fan and return fan are the fan operating frequency; the supply fan and return fan frequency are predicted and controlled according to the changing trend of the temperature in the station.

[0148] 4. Data display

[0149] The monitoring platform is used to display the operating status of each component in real time. In addition, the status of the component is diagnosed according to the operating parameters of the component. When the status of the component poses a safety hazard, the monitoring platform can provide early warning, allowing operators to take preventive measures in advance, reduce the risk of system failure, and improve the system's operation and maintenance efficiency.

[0150] Embodiment 2

[0151] In one embodiment of the present disclosure, a ventilation and air conditioning control system is provided, including an acquisition module and a control module:

[0152] The acquisition module is configured to: acquire environmental parameters, state parameters and equipment operation parameters collected in real time;

[0153] The control module is configured to: based on the above parameters and according to the change trend of the temperature in the station, predict and control the outlet water temperature of the chiller, the operating frequency of the supply fan and the return fan, and assist in following the chilled water pump, the cooling water pump and the cooling tower fan, so as to control the operation of the entire ventilation and air conditioning system with the highest efficiency and the lowest energy consumption;

[0154] Among them, the outlet water temperature of the chiller adopts a method that combines predictive control and real-time feedback correction. The outlet water temperature of the chiller is predicted in advance according to the changing trend of the temperature in the station, which is used to control the operating status of the chiller; the outlet water temperature of the chiller is corrected in real time through the error between the actual station temperature and the predicted station temperature.

[0155] Embodiment 3

[0156] The purpose of this embodiment is to provide a computer-readable storage medium.

[0157] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps in a ventilation and air-conditioning control method as described in Embodiment 1 of the present disclosure.

[0158] Embodiment 4

[0159] The purpose of this embodiment is to provide an electronic device.

[0160] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the steps in a ventilation and air conditioning control method as described in Embodiment 1 of the present disclosure are implemented.

[0161] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for controlling ventilation and air conditioning, characterized in that: include: Obtain real-time collected environmental parameters, status parameters and equipment operation parameters; Based on the above parameters, according to the temperature change trend in the station, the outlet water temperature of the chiller, the operating frequency of the supply fan and the return fan are predicted and controlled, and the chilled water pump, cooling water pump and cooling tower fan are assisted in follow-up control, so as to achieve the highest efficiency and lowest energy consumption of the entire ventilation and air-conditioning system. The outlet water temperature of the chiller adopts a method combining predictive control and real-time feedback correction, predicting the outlet water temperature of the chiller in advance according to the change trend of the station temperature, so as to control the operation state of the chiller; and performing real-time feedback correction on the outlet water temperature of the chiller according to the error between the actual station temperature and the predicted station temperature; Wherein, the environmental parameters include indoor and outdoor temperature and humidity; The state parameters include temperature, pressure and flow rate of various parts of the ventilation and air conditioning system; The equipment operating parameters include chiller operating parameters, refrigeration pump cooling pump frequency, cooling tower fan frequency, and supply fan return fan frequency; The specific steps of predicting and controlling the outlet water temperature of the chiller are as follows: According to the chiller response curve and the predicted control parameters, the station temperature is predicted; According to the predicted value of the station temperature, the station temperature control target and the fluctuation of the outlet water temperature, the predicted value of the outlet water temperature of the chiller is determined to control the operating status of the chiller; The temperature in the station is predicted based on the response curve of the chiller combined with the predicted control parameters, specifically: The response characteristics of the chiller are tested experimentally, and the chiller response curve is constructed as a prediction benchmark for the chiller outlet water temperature adjustment; in each control cycle, the station temperature at a future time from the current control cycle is predicted by combining the response characteristics of the chiller and the chiller outlet water temperature parameters predicted in the previous control cycle; The specific implementation method of testing the response characteristics of the chiller by experiment is as follows: When the temperature in the station is stable, lower the outlet water temperature of the chiller and test the temperature change curve in the station; set the sampling time ,in N is the number of sampling points, T is the sampling period, and the temperature in the station is measured at each sampling moment. Indicates that after a period of time, the temperature in the station tends to be stable, using a finite set Characterize the response characteristics of the chiller; The response characteristic obtained by the above method is the temperature change curve of the station when the fixed control parameters are applied to the chiller; assuming that the current moment is k Moment, you can get the future N The predicted value of the station temperature at a certain moment is calculated as follows: in, Indicated in k Always k + i The predicted temperature value in the station at the time, express k The chiller outlet water temperature control increment at the moment, Indicates the number of sampling points; In the actual control process, the outlet water temperature of the chiller is in a dynamic adjustment process. M Different chiller outlet water temperatures Under this effect, the station temperature output value at each moment in the future is: ， System k Always looking to the future P The output prediction function at each moment can be expressed as: in, A is the response characteristic matrix, M ≤ P ≤ N , specifically expressed as: After obtaining the prediction results of the station temperature, predict the chiller outlet water temperature control increment , assuming that the current k time, predict the M The predicted chiller outlet water temperature can be controlled in the future under the control of each predicted outlet water temperature. P The station temperature at the moment is as close to the target value as possible ; In addition, to prevent the chiller outlet water temperature from being controlled by the predicted value of the increment The fluctuation is too large, increase the constraint value, and get k Chiller outlet water temperature control increment The method of determining is as follows: in, represents the weight of the change in the temperature tracking error within the station, Indicates the weight of the change in the control effect on the chiller outlet water temperature; Combining the above prediction function, the vector form of rolling optimization is: in: , , ； In order to ask The minimum value that satisfies the above formula is Take the derivative and set it equal to 0, and only take By acting on the object with the first element of , we can get the predicted value of the chiller outlet water temperature control increment: in, .

2. A ventilation and air conditioning control method according to claim 1, characterized in that: The specific steps of predicting and controlling the operating frequency of the supply fan and the return fan are as follows: Calculate the cooling capacity of the chiller based on the chilled water flow rate and supply and return water temperatures; Based on the cooling capacity, combined with the target station temperature and predicted temperature, the heat load is predicted; Based on the heat load, the operating frequency of the supply fan and the return fan is determined for the control of the supply fan and the return fan.

3. A ventilation and air conditioning control method according to claim 1, characterized in that: The following control of the chilled water pump adopts a closed-loop control algorithm, takes the pressure at the most unfavorable end of the entire system to meet the requirements as the control target, monitors the pressure at the most unfavorable end of the entire system in real time, and adjusts the operating frequency of the chilled water pump through feedback control.

4. A ventilation and air conditioning control method as claimed in claim 1, characterized in that: The following control of the cooling water pump takes ensuring that the condenser is at a constant temperature as a control target, and adopts a closed-loop control algorithm to control the frequency of the cooling water pump.

5. A ventilation and air conditioning control method as claimed in claim 1, characterized in that: The following control of the cooling tower fan obtains the target value of the cooling tower outlet water temperature according to the outdoor temperature and humidity. For the fan using switch control, the deviation between the measured cooling tower outlet water temperature and the target temperature is compared, and the cooling tower outlet water temperature is controlled in real time through the switch control of the fan; for the cooling tower fan using frequency conversion control, a closed-loop control algorithm is used to take the target value of the cooling tower outlet water temperature as the control target, and the fan frequency is adjusted in real time to ensure that the actual outlet water temperature is maintained near the target value.

6. A ventilation and air conditioning control system, characterized in that: Including acquisition module and control module: The acquisition module is configured to: acquire environmental parameters, state parameters and equipment operation parameters collected in real time; The control module is configured to: based on the above parameters and according to the change trend of the temperature in the station, predict and control the outlet water temperature of the chiller, the operating frequency of the supply fan and the return fan, and assist in following the chilled water pump, the cooling water pump and the cooling tower fan, so as to control the operation of the entire ventilation and air conditioning system with the highest efficiency and the lowest energy consumption; The outlet water temperature of the chiller adopts a method combining predictive control and real-time feedback correction, predicting the outlet water temperature of the chiller in advance according to the change trend of the station temperature, so as to control the operation state of the chiller; and performing real-time feedback correction on the outlet water temperature of the chiller according to the error between the actual station temperature and the predicted station temperature; Wherein, the environmental parameters include indoor and outdoor temperature and humidity; The state parameters include temperature, pressure and flow rate of various parts of the ventilation and air conditioning system; The equipment operating parameters include chiller operating parameters, refrigeration pump cooling pump frequency, cooling tower fan frequency, and supply fan return fan frequency; The specific steps of predicting and controlling the outlet water temperature of the chiller are as follows: According to the chiller response curve and the predicted control parameters, the station temperature is predicted; According to the predicted value of the station temperature, the station temperature control target and the fluctuation of the outlet water temperature, the predicted value of the outlet water temperature of the chiller is determined to control the operating status of the chiller; The temperature in the station is predicted based on the response curve of the chiller combined with the predicted control parameters, specifically: The response characteristics of the chiller are tested experimentally, and the chiller response curve is constructed as a prediction benchmark for the chiller outlet water temperature adjustment; in each control cycle, the station temperature at a future time from the current control cycle is predicted by combining the response characteristics of the chiller and the chiller outlet water temperature parameters predicted in the previous control cycle; The specific implementation method of testing the response characteristics of the chiller by experiment is as follows: When the temperature in the station is stable, lower the outlet water temperature of the chiller and test the temperature change curve in the station; set the sampling time ,in N is the number of sampling points, T is the sampling period, and the temperature in the station is measured at each sampling moment. Indicates that after a period of time, the temperature in the station tends to be stable, using a finite set Characterize the response characteristics of the chiller; The response characteristic obtained by the above method is the temperature change curve of the station when the fixed control parameters are applied to the chiller; assuming that the current moment is k Moment, you can get the future N The predicted value of the station temperature at a certain moment is calculated as follows: in, Indicated in k Always k + i The predicted temperature value in the station at the time, express k The chiller outlet water temperature control increment at the moment, Indicates the number of sampling points; In the actual control process, the outlet water temperature of the chiller is in a dynamic adjustment process. M Different chiller outlet water temperatures Under this effect, the station temperature output value at each moment in the future is: ， System k Always looking to the future P The output prediction function at each moment can be expressed as: in, A is the response characteristic matrix, M ≤ P ≤ N , specifically expressed as: After obtaining the prediction results of the station temperature, predict the chiller outlet water temperature control increment , assuming that the current k time, predict the M The predicted chiller outlet water temperature can be controlled in the future under the control of each predicted outlet water temperature. P The station temperature at the moment is as close to the target value as possible ; In addition, to prevent the chiller outlet water temperature from being controlled by the predicted value of the increment The fluctuation is too large, increase the constraint value, and get k Chiller outlet water temperature control increment at any time The method of determining is as follows: in, represents the weight of the change in the temperature tracking error within the station, Indicates the weight of the change in the control effect on the chiller outlet water temperature; Combining the above prediction function, the vector form of rolling optimization is: in: , , ； In order to ask The minimum value that satisfies the above formula is Take the derivative and set it equal to 0, and only take By acting on the object with the first element of , we can get the predicted value of the chiller outlet water temperature control increment: in, .

7. An electronic device, comprising: a memory for non-transitory storage of computer readable instructions; a processor for executing the computer-readable instructions; Wherein, when the computer-readable instructions are executed by the processor, the method according to any one of claims 1 to 5 is executed.

8. A storage medium, characterized in that: The computer-readable instructions are non-transitorily stored, wherein when the computer-readable instructions are executed by a computer, the method according to any one of claims 1 to 5 is performed.

Images