CN105865105A - Control method and device for chilled water secondary pump system - Google Patents

Abstract

The invention discloses a control method and device for a chilled water secondary pump system. A particular implementation mode of the method includes the steps that the flow amount of chilled water in the chilled water secondary pump system and the pressure value between a water supply end and a water return end are collected; the number reference value of secondary pumps in an operating state is determined based on the pressure value difference between the water supply end and the water returning end, the flow amount and the preset first impedance of the chilled water secondary pump system; and operation of at least one secondary pump in the chilled water secondary pump system is controlled based on the number of the secondary pumps in the operating state and the number reference value. By means of the implementation mode, the energy consumption of the chilled water secondary pump system is effectively lowered.

Description

Control method and device for chilled water secondary pump system

technical field

The present application relates to the field of automatic control, in particular to a control method and device for a chilled water secondary pump system.

Background technique

With the rising cost of energy and the emphasis on green environmental protection, the demand for energy saving in data centers is becoming stronger and stronger. As a large energy consumer in large data centers, cooling water systems save and reduce the energy consumption of related equipment in the system, which is of great significance for the improvement of data center infrastructure efficiency and the reduction of power usage efficiency (Power Usage Effectiveness).

In the prior art, the control method for the chilled water secondary pump system is to control the frequency of the secondary pump through the pressure difference, that is, the difference between the chilled water pressure at the water supply end and the return water end is used as the control variable, and by comparing the actual measured value The frequency of the secondary pump is controlled with the set value, and the number of secondary pumps operating is mainly determined by artificially judging the load. In this way, the adjustment of the number of secondary pumps operating in the chilled water secondary pump system is not perfect At the same time, in the process of adjusting the number of secondary pumps, only the operation of the secondary pump itself is paid attention to without considering the change of the characteristics of the pipe network where the secondary pump is located, resulting in the length of the secondary pump during actual operation. Working in the low-efficiency range of the characteristic curve for a long time makes the efficiency of the chilled water secondary pump system low and greatly increases power consumption.

Contents of the invention

The purpose of this application is to propose an improved control method and device for the chilled water secondary pump system, so as to solve the technical problems mentioned in the background technology section above.

In a first aspect, the present application provides a control method for a chilled water secondary pump system, the chilled water secondary pump system includes a water supply end, a return water end, and a water supply end connected between the water supply end and the return water end pipeline and at least one secondary pump for driving chilled water to flow in the pipeline, the method includes: collecting the flow rate of chilled water in the chilled water secondary pump system and the water supply end and the return water end The pressure value between; based on the pressure difference between the water supply end and the return water end, the flow rate and the preset first impedance of the chilled water secondary pump system, determine the two A reference value for the quantity of secondary pumps; based on the quantity of secondary pumps in the current operating state and the quantity reference value, the operation of at least one secondary pump in the chilled water secondary pump system is controlled.

In some embodiments, the controlling the operation of at least one secondary pump in the chilled water secondary pump system based on the number of secondary pumps in the current operating state and the quantity reference value includes: judging that in the current operating state Whether the number of the secondary pumps and the quantity reference value are equal; if they are equal, then collect the chilled water temperature values of the water supply end and the return water end; based on the chilled water temperature values of the water supply end and the return water end Adjust the operating frequency of the secondary pump in the current operating state within the preset range of the difference between the temperature difference and the chilled water temperature value.

In some embodiments, the method further includes: judging whether the chilled water temperature difference between the water supply end and the return water end is within the preset range of the chilled water temperature difference; If it is within the preset range, the valve opening of the regulating valve is increased. The regulating valve is arranged in the pipeline and is used to control the flow of chilled water in the pipeline.

In some embodiments, based on the pressure value difference between the water supply end and the return water end, the flow rate and the preset first impedance of the chilled water secondary pump system, it is determined that The reference value of the number of secondary pumps includes: determining the value range of the number of secondary pumps in the operating state according to the total number of secondary pumps included in the chilled water secondary pump system; based on the pressure value difference, the the flow rate, respectively calculate the second impedance of the chilled water secondary pump system corresponding to each value within the value range, and obtain a set of second impedances; select a set of second impedances that meets the preset conditions The second impedance of the second impedance, the preset condition is set based on the first impedance; the number of secondary pumps in the operating state corresponding to the selected second impedance is determined as a reference for the number of secondary pumps in the operating state value.

In some embodiments, the first impedance is preset based on a characteristic curve of a secondary pump included in the chilled water secondary pump system.

In a second aspect, the present application provides a control device for a chilled water secondary pump system. The chilled water secondary pump system includes a water supply end, a water return end, and a pipeline connected between the water supply end and the water return end. And at least one secondary pump for driving chilled water to flow in the pipeline, characterized in that the device includes: a collection unit for collecting the flow of chilled water in the chilled water secondary pump system and the water supply The pressure value between the water supply end and the return water end; the determination unit is used for based on the pressure value difference between the water supply end and the water return end, the flow rate and the preset chilled water secondary pump The first impedance of the system is used to determine the reference value of the number of secondary pumps in the operating state; the control unit is used to control the number of secondary pumps in the chilled water secondary pump system based on the number of secondary pumps in the current operating state and the reference value. at least one of the secondary pumps is running.

In some embodiments, the control unit is further configured to: determine whether the number of secondary pumps in the current operating state is equal to the number reference value; if they are equal, collect the data of the water supply end and the water return end Chilled water temperature value: adjust the operating frequency of the secondary pump in the current operating state based on the difference between the chilled water temperature value of the water supply end and the return water end and the preset range of the chilled water temperature value difference.

In some embodiments, the device further includes: a regulating valve regulating unit configured to determine whether the temperature difference between the chilled water at the water supply end and the return water end is within a preset range of the chilled water temperature difference; if Within the preset range of the chilled water temperature difference, the opening of the regulating valve is increased. The regulating valve is arranged in the pipeline and is used to control the flow of chilled water in the pipeline.

In some embodiments, the determination unit includes: a value range determination module configured to determine the value of the number of secondary pumps in the operating state according to the total number of secondary pumps included in the chilled water secondary pump system Value range; calculation module, configured to calculate the second impedance of the chilled water secondary pump system corresponding to each value in the value range based on the pressure value difference and the flow rate, to obtain the second impedance A set; a selection module, configured to select a second impedance that meets a preset condition in the set of second impedances, the preset condition is set based on the first impedance; a quantity reference value determination module, configured The method is used to determine the quantity of the secondary pumps in the running state corresponding to the selected second impedance as the reference value of the quantity of the secondary pumps in the running state.

In some embodiments, the first impedance is preset based on a characteristic curve of a secondary pump included in the chilled water secondary pump system.

The control method and device for the chilled water secondary pump system provided by the present application collect the flow of chilled water in the chilled water secondary pump system and the pressure value between the water supply end and the return water end, and then based on the The pressure value difference between the water supply end and the return water end, the flow rate and the preset first impedance of the chilled water secondary pump system, determine the reference value of the number of secondary pumps in the running state, and finally Based on the number of secondary pumps in the current operating state and the quantity reference value, the operation of at least one secondary pump in the chilled water secondary pump system is controlled to effectively reduce energy consumption of the chilled water secondary pump system.

Description of drawings

Other characteristics, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is the flow chart of an embodiment of the control method of the chilled water secondary pump system according to the present application;

FIG. 2 is a schematic diagram of an application scenario of a control method for a chilled water secondary pump system according to the present application;

Fig. 3 is a flow chart of another embodiment of the control method of the chilled water secondary pump system according to the present application;

Fig. 4 is a structural schematic diagram of an embodiment of a control device of a chilled water secondary pump system according to the present application;

Fig. 5 is a schematic structural diagram of a controller suitable for implementing the embodiment of the present application.

detailed description

The application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain related inventions, rather than to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the related invention are shown in the drawings.

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

Referring to FIG. 1 , it shows a flow 100 of an embodiment of a control method for a chilled water secondary pump system according to the present application.

The chilled water secondary pump system includes a water supply end, a water return end, a pipeline connected between the water supply end and the water return end, and at least one secondary pump for driving chilled water to flow in the pipeline. The above-mentioned chilled water secondary pump system The control method comprises the following steps:

Step 101, collect the flow rate of chilled water in the chilled water secondary pump system and the pressure values at the water supply end and the water return end.

In this embodiment, the electronic device on which the method for controlling the secondary chilled water pump system runs may be a controller, such as a programmable logic controller (Programmable Logic Controller, PLC), or other programmable devices. The controller can read the flow rate of chilled water collected by the collection device in the system and the pressure values of the water supply end and the return water end. Acquisition devices include flowmeters and pressure gauges.

In this embodiment, chilled water is the medium for transferring cold energy to the end load through the precision air conditioner for cold and heat exchange, and is the carrier for exporting the heat of the load. The secondary pump refers to the secondary loop formed by the load-side water pump, load-side terminal equipment, piping system and bypass pipe. Corresponding to the secondary pump in this embodiment, the device for providing the above-mentioned chilled water may include a primary pump. The primary pump refers to the water pump corresponding to the chiller on the cold source side, and forms a primary loop with the chiller and the bypass pipe. road. The flow rate of the chilled water is the total flow rate of the secondary side, which can be measured by installing a flow meter at the return end of the chilled water.

Step 102, based on the pressure difference between the water supply end and the return water end, the flow rate and the preset first impedance of the chilled water secondary pump system, determine the reference value of the number of secondary pumps in the running state.

In this embodiment, based on the pressure value and flow rate of the water supply end and the water return end obtained in step 101, and the preset first impedance, the above-mentioned controller can first calculate the pressure value difference between the water supply end and the water return end; and then by Based on the pressure value difference, the flow rate and the first impedance, the reference value of the quantity of the secondary pump in the running state is determined. The impedance can be understood as the pipe network impedance on the secondary side, and the first impedance can be the corresponding impedance value when the secondary pump in the chilled water secondary pump system has the highest operating efficiency. The reference value of the number of secondary pumps in the operating state may be the number of secondary pumps running when the operating efficiency of the secondary pumps in the chilled water secondary pump system is the highest.

In some optional implementation manners of this embodiment, the first impedance may be preset based on a characteristic curve of a secondary pump included in the chilled water secondary pump system. The main performance parameters of the pump include flow Q, head H, shaft power N and efficiency η. The relationship between performance parameters is measured by experiments, and a set of measured relationship curves is called the characteristic curve or working performance curve of the pump. This curve is usually provided by the pump manufacturer and attached to the pump test sample or manual. Take the η-Q curve in the characteristic curve as an example, the η-Q curve reflects the relationship between the efficiency of the pump and the flow rate. The highest efficiency point in the η-Q curve is usually called the design point or operating point. The pump works most economically at the flow rate and head corresponding to the highest efficiency, so the Q, H, and N values corresponding to the highest efficiency point are called the best working condition parameters. The first impedance of the chilled water secondary pump system can also be analyzed and calculated from the above parameters.

In some optional implementations of this embodiment, in order to determine the reference value of the number of secondary pumps in the operating state, firstly, the number of secondary pumps in the operating state can be determined according to the total number of secondary pumps included in the chilled water secondary pump system. The value range of the number of secondary pumps, for example, the chilled water secondary pump system includes three secondary pumps, then the value range of the number of secondary pumps in the running state is one to three; then according to the current state of the water supply end The difference between the pressure value △P and the return water end and the flow rate Q of chilled water in the chilled water secondary pump system can be calculated by the formula K=△P/(Q/t) ² corresponding to the number of secondary pumps. Two impedances, wherein K represents the second impedance, t is the operating number of secondary pumps, and the value range of t can be the value range of the number of secondary pumps in the above-mentioned operating state; finally, the calculated second impedance A second impedance meeting the preset condition is selected from the set, and the number of secondary pumps in the operating state corresponding to the selected second impedance is determined as a reference value for the number of secondary pumps in the operating state. Wherein, the preset condition is set based on the first impedance, for example, selecting the second impedance meeting the preset condition may be selecting the second impedance closest to the first impedance. There may also be multiple second impedances closest to the first impedance, and at this time, the corresponding second impedance with the smallest number of secondary pumps in operation may be selected. For example, the first impedance is 1.0×10 ¹⁰ pa, the calculated second impedance is 1.01×10 ¹⁰ pa when running five secondary pumps, and the second impedance is 0.99×10 ¹⁰ pa when running three secondary pumps, then, The reference value of the number of secondary pumps in the running state is three.

In some optional implementations of this embodiment, K in the formula K=△P/(Q/t) ² may also be equal to the first impedance, and at the same time be substituted into the obtained current state between the water supply end and the return water end Calculate the value of t from the pressure difference △P between them and the flow rate Q of chilled water in the chilled water secondary pump system. The value t obtained at this time may not be an integer, and the number closest to the obtained value t may be selected within the value range of the number of secondary pumps in the running state as the quantity reference value.

Step 103: Control the operation of at least one secondary pump in the chilled water secondary pump system based on the quantity of secondary pumps in the current operating state and the quantity reference value.

In this embodiment, based on the quantitative reference value determined in step 102, the controller may control the operation of at least one secondary pump in the chilled water secondary pump system through a direct digital controller (Direct Digital Controller, DDC). For example, the controller may equalize the quantity of the secondary pump to the quantity reference value by turning on or off the secondary pump.

In some optional implementations of this embodiment, it can be judged whether the number of secondary pumps in the current operating state is equal to the above-mentioned number reference value; if they are equal, then collect the chilled water temperature values at the water supply end and the return water end; The temperature difference between the chilled water at the water supply end and the return water end and the preset range of the chilled water temperature difference adjust the operating frequency of the secondary pump in the current operating state. During the operation of the chilled water secondary pump system, the temperature difference between the chilled water at the water supply end and the return water end can directly reflect the load change, and it is also the most sensitive set of parameters in the chilled water system. The frequency of the secondary pump can be adjusted in time through the feedback of the temperature difference of the chilled water, so as to respond to the change of the load in the first time. When the load increases, the temperature difference between the chilled water at the water supply end and the return water end increases accordingly. At this time, increase the frequency of the secondary pump and increase the delivery volume of chilled water to match the load power; when the load decreases, the water supply The temperature difference between the chilled water at the water end and the return water end is also reduced. At this time, the frequency of the secondary pump is reduced to reduce the power consumption of each secondary pump.

In some optional implementations of this embodiment, it can also be judged whether the chilled water temperature difference between the water supply end and the return water end is within the preset range of the chilled water temperature difference; Within the range, the valve opening of the regulating valve is increased, and the regulating valve is arranged in the pipeline to control the flow of chilled water in the pipeline. When the temperature value difference is within the preset range, it means that the power of the secondary pump matches the load power. At this time, the opening of the regulating valve is increased to the maximum, reducing the system resistance, thereby reducing the power consumed by conveying chilled water, and further improving system efficiency.

Continuing to refer to FIG. 2 , FIG. 2 is a schematic diagram of an application scenario of a control method for a chilled water secondary pump system according to this embodiment, including a typical data center chilled water secondary side device and its control module.

In Fig. 2, the thick solid line may represent the water supply and return pipeline of the chilled water on the secondary side, and the dotted line may represent the signal transmission path between various devices and their corresponding controllers.

The control module in Figure 2 mainly includes control equipment, transmission equipment and host computer. The upper computer can include the server and/or workstation of the chilled water secondary pump system, and has human-computer interaction functions such as remote control, parameter configuration, interface display, and data monitoring. The transmission device can be a network switch, and a network bridge is built between the upper computer and the lower controller through the industrial Ethernet Ethernet. The control equipment includes a DDC controller and a PLC controller, both of which adopt the Modbus communication protocol industrial field bus RS485 communication interface design, and are connected with the terminal equipment. Among them, the PLC controller is equipped with the core program of the control method of the chilled water secondary pump system, including the determination of the number of secondary pumps in operation, the frequency adjustment of a single secondary pump, the loading and unloading control of the secondary pump, and the reading of the secondary pump. The feedback value of various sensors and the opening degree of the regulating valve on the secondary side pipeline is used to complete relevant calculation or control. The DDC controller is configured to individually control and detect each secondary pump, and the PLC controller and each DDC controller can be interconnected through Ethernet.

The chilled water secondary side device in Figure 2 mainly includes secondary pump units, terminal execution equipment and various sensors on the pipeline. The secondary pump unit includes several secondary pumps, regulating valves and butterfly valves, among which the secondary pumps and regulating valves are respectively connected to DDC or PLC controllers through RS485 bus to realize remote control. The butterfly valve can be manually controlled to ensure that the pipeline can be cut off on the spot when the regulating valve is not working properly. End effectors may include air conditioning units, water valves and fan coils. Various sensors on the chilled water ring network pipeline include chilled water return end temperature sensor T ₁ , chilled water supply end temperature sensor T ₂ , terminal differential pressure sensor P and secondary side flowmeter. The output ends of various sensors can pass through The RS485 bus is connected with the I/O module of the PLC controller.

The method provided by the above-mentioned embodiments of the present application collects the flow rate of chilled water in the chilled water secondary pump system and the pressure value between the water supply end and the return water end, based on the pressure value difference between the water supply end and the return water end, The flow rate and the preset first impedance of the chilled water secondary pump system determine the reference value of the number of secondary pumps in the operating state, and control the secondary pump of chilled water based on the number of secondary pumps in the current operating state and the reference value of the quantity. The operation of at least one secondary pump in the pump system effectively reduces the energy consumption of the chilled water secondary pump system.

Further referring to FIG. 3 , it shows a flow 300 of another embodiment of the control method of the chilled water secondary pump system. The flow 300 of the control method includes the following steps:

Step 301, system initialization, judging whether the status of each unit of the system is normal.

In this embodiment, after the system is powered on and initialized, the controller reads the feedback information of the secondary pump unit and the terminal equipment. The feedback information of the secondary pump unit and the terminal equipment includes the current number of activated chilled water secondary pumps _t0 and Its operating frequency F, the state of each unit corresponding to the regulating valve, the water valve opening R ₀ of the terminal air-conditioning unit and the fan speed V ₀ , and judge whether the operating status of the unit and the secondary pump unit is normal. If the unit is normal, it goes to step 302, and if it is judged that the status of each unit of the system is normal, it goes to step 303.

Step 302, alarm.

In this embodiment, if it is detected that the operating parameters of each unit of the system do not match the preset standard operating parameters, the parameter information of the abnormal parameter and the information of the unit to which it belongs will be sent to the upper computer by means of an alarm.

Step 303, collect the current terminal pressure difference ΔP and the secondary side flow Q, and obtain the pipe network impedance K ₀ set by the host computer.

In this embodiment, the upper computer may be a server and/or a workstation. The collection of the current end pressure difference △P and the flow rate Q of the secondary side can be carried out regularly, and the collection cycle can be set according to the actual situation.

The pipe network impedance K ₀ set by the host computer can be calculated according to the analysis and calculation of the characteristic curve of the secondary pump.

Step 304, simulating the situation of turning on different numbers of secondary pumps, and analyzing the change of pipe network impedance.

That is to calculate K=△P/Q ² , △P/(Q/2) ² ,...△P/(Q/n) ² respectively, and make a difference with the set value K ₀ , where n represents the operable The total number of secondary pumps.

Step 305 , determining the number of secondary pumps that are turned on corresponding to the minimum change in pipe network impedance as the optimal number of secondary pumps to be turned on under the current conditions.

The analysis result of the impedance change of the pipe network in step 304 can be obtained, that is, the value of |△P/(Q/t) ² -K ₀ | when different numbers of secondary pumps are turned on, if the absolute value of the impedance change of the pipe network exists The minimum value, namely |△P/(Q/t) ² -K ₀ |min exists, then the number of secondary pumps corresponding to this minimum value t is the number of secondary pumps corresponding to the minimum change in pipe network impedance; if There are two or more values of |△P/(Q/t) ² -K ₀ | that are equal, that is, |△P/(Q/t ₁ ) ² -K ₀ |＝…＝|△P/( Q/t _m ) ² -K ₀ |, the minimum number of secondary pumps is selected, that is, t'=min{t ₁ ,...,t _m } is the optimal secondary pump under the current conditions Number of pumps turned on.

Step 306, judging whether the current running number of secondary pumps is equal to the optimal number of secondary pumps under current conditions.

Compare the current running number t ₀ of secondary pumps read in step 301 with the optimal running number t′ of secondary pumps determined in step 305 under the current conditions. If both are equal, go to step 308; if not, go to step 307.

Step 307, adjusting the running number of secondary pumps to the optimal running number of secondary pumps under the current conditions.

When the number of secondary pumps is adjusted to the optimal number of secondary pumps under the current conditions t', due to the change in the number of secondary pumps, the secondary side flow rate and terminal pressure difference of the chilled water system also change accordingly. Go back to step 303 again, read the corresponding parameters, and calculate the new optimal number of secondary pumps in operation until the current number of secondary pumps in operation is equal to the optimal number of secondary pumps in operation.

Step 308, collect the temperatures T ₁ and T ₂ of the chilled water at the water supply and return end of the secondary side to calculate the temperature difference ΔT, and judge whether ΔT is equal to the preset temperature difference value.

If otherwise, go to step 309, if yes, adjust the water valve of the terminal air-conditioning unit to maximize its opening, reduce the system resistance, and thereby reduce the power consumed by transporting the brine.

In this embodiment, when judging whether ΔT is equal to a preset temperature difference value, it may also be judging whether ΔT is within a range of a preset temperature difference value. For example, the preset temperature difference value is 10 degrees Celsius, and the preset temperature difference value can range from 8 degrees Celsius to 12 degrees Celsius. When △T is 9 degrees Celsius, it is also approximately considered that △T is equal to the preset temperature difference value, thereby avoiding subsequent steps Unnecessary frequent adjustments in .

Step 309 , adjusting the frequency of the secondary pump according to the magnitude relationship between the temperature difference ΔT and the preset temperature difference value, so that the temperature difference ΔT matches the preset temperature difference value.

When the temperature difference △T of the supply and return water is greater than the preset temperature difference value, increase the frequency of the secondary pump according to the preset gradient; Secondary pump frequency, thus step by step secondary pump frequency, finally make the temperature difference between supply and return water equal or approximately equal to the preset temperature difference value.

Step 310, judging whether the variation of ΔP and Q before and after adjusting the frequency of the secondary pump exceeds a preset range.

If yes, go back to step 303. After the frequency of the secondary pump is adjusted, the pressure difference △P at the end of the system and the flow rate of the secondary side of chilled water change. If the change is too large, you can go back to step 303 to continue collecting relevant parameters, and judge the operating mode of the system again to ensure that the secondary pump is always All can operate in the high-efficiency range of its characteristic curve. If the pressure difference △P at the end of the system and the flow rate on the secondary side of the chilled water do not change much after the frequency of the secondary pump is adjusted, the process 300 of the control method for the secondary pump system of chilled water can be repeatedly executed according to the preset cycle to avoid excessive data volume. The situation where the large system is unstable.

It can be seen from FIG. 3 that, compared with the embodiment corresponding to FIG. 1 , the flow 300 of the method for controlling the secondary chilled water pump system in this embodiment highlights the importance of adjusting the number of secondary pumps and the operating frequency of the secondary pumps. step. Therefore, the solution described in this embodiment can save more power consumption of the secondary pump equipment in the system, thereby realizing efficient operation of the chilled water secondary pump system.

The foregoing embodiment of the present application is an optimization of the existing secondary pump operation mode of the data center.

First, the control quantity of the frequency of a single secondary pump is changed from the pressure difference to the temperature difference of supply and return water, so that the frequency of the secondary pump is more sensitive to the change of the end load, and the adjustment is more timely. When the load becomes smaller, the frequency of the secondary pump decreases rapidly, which reduces its running time in the high frequency band and saves the energy consumption of each device. At the same time, through the adjustment of the water pump frequency, the opening of the water valve of the air conditioner in operation can be maximized, the system resistance can be reduced, and the power consumed by conveying the refrigerant can be reduced.

Second, pay attention to the changes in the characteristics of the system pipe network at all times, and determine the number of secondary pumps operating under the current system conditions by comparing the impedance of the pipe network at the same frequency. This solution enables the system to ensure that each pump is closest to the working point of its own characteristic curve, and at the same time, the number of secondary pumps is as small as possible, which greatly reduces the energy consumption of the entire system.

Third, the control strategy proposed by the present invention improves the defects of the original scheme, realizes the comprehensive automation of the secondary side equipment, improves the intelligence of the data center, reduces the work of human participation in operation, and saves a certain amount of time. human capital.

Further referring to FIG. 4, as an implementation of the methods shown in the above-mentioned figures, the present application provides an embodiment of a control device for a chilled water secondary pump system. This device embodiment is similar to the method embodiment shown in FIG. 1 Correspondingly, the device can be specifically applied to various electronic devices.

As shown in Figure 4, the chilled water secondary pump system in this embodiment includes a water supply end, a water return end, a pipeline connected between the water supply end and the water return end, and at least one secondary pump for driving chilled water to flow in the pipeline. secondary pump. The control device 400 of the chilled water secondary pump system includes: an acquisition unit 401 , a determination unit 402 and a control unit 403 . Wherein, the collection unit 401 is configured to collect the flow of chilled water in the chilled water secondary pump system and the pressure value between the water supply end and the return water end; the determination unit 402 is configured to collect The pressure value difference, the flow rate and the preset first impedance of the chilled water secondary pump system determine the reference value of the number of secondary pumps in the operating state; and the control unit 403 is configured to be based on the number of secondary pumps in the current operating state A quantity and a quantity reference control the operation of at least one secondary pump in the chilled water secondary pump system.

In this embodiment, the electronic device on which the control method of the chilled water secondary pump system runs can be a controller, such as a programmable logic controller, or other programmable devices, and the controller can read the The flow rate of chilled water collected by the device, and the pressure values of the water supply end and the return water end. Acquisition devices include flowmeters and pressure gauges.

In this embodiment, based on the pressure value and flow rate of the water supply end and the water return end obtained by the acquisition unit 401, and the preset first impedance, the above-mentioned controller can first calculate the pressure value difference between the water supply end and the water return end; and then Based on the above pressure value difference, flow rate and first impedance, the reference value of the quantity of the secondary pump in the running state is determined. The impedance can be understood as the pipe network impedance on the secondary side, and the first impedance can be the corresponding impedance value when the secondary pump in the chilled water secondary pump system has the highest operating efficiency. The reference value of the number of secondary pumps in the operating state may be the number of secondary pumps running when the operating efficiency of the secondary pumps in the chilled water secondary pump system is the highest.

In this embodiment, based on the quantity reference value determined by the determination unit 402, the controller may control the operation of at least one secondary pump in the chilled water secondary pump system through a direct digital controller. For example, the controller may equalize the quantity of the secondary pump to the quantity reference value by turning on or off the secondary pump.

In some optional implementations of this embodiment, the control unit 403 is further configured to determine whether the number of secondary pumps in the current operating state is equal to the number reference value; Water temperature value: adjust the operating frequency of the secondary pump in the current operating state based on the difference between the chilled water temperature value at the water supply end and the return water end and the preset range of the chilled water temperature value difference.

In some optional implementations of this embodiment, the above device further includes: a regulating valve regulating unit, configured to determine whether the temperature difference between the chilled water at the water supply end and the return water end is within a preset range of the chilled water temperature difference ; If it is within the preset range of the temperature difference of the chilled water, increase the valve opening of the regulating valve, and the regulating valve is arranged in the pipeline to control the flow of chilled water in the pipeline.

In some optional implementations of this embodiment, the determination unit 402 includes: a value range determination module configured to determine the secondary pumps in the running state according to the total number of secondary pumps included in the chilled water secondary pump system The value range of the number of pumps; the calculation module is configured to calculate the second impedance of the chilled water secondary pump system corresponding to each value in the above value range based on the pressure value difference and the flow rate, and obtain a set of second impedances; The selection module is configured to select a second impedance that meets the preset condition in the set of second impedances, and the preset condition is set based on the first impedance; the quantity reference value determination module is configured to use the selected second impedance The number of secondary pumps in the corresponding running state is determined as the reference value of the number of secondary pumps in the running state.

In some optional implementation manners of this embodiment, the first impedance is preset based on a characteristic curve of a secondary pump included in the chilled water secondary pump system.

Referring now to FIG. 5 , it shows a schematic structural diagram of a controller 500 suitable for implementing the embodiment of the present application.

As shown in FIG. 5 , the controller 500 includes a central processing unit (CPU) 501 that can execute various appropriate actions and processes according to programs in a storage section 506 . The CPU 501 is connected to an input/output (I/O) interface 503 via a bus 502 .

The following components are connected to the I/O interface 503: an input section 504; an output section 505; a storage section 506 including a hard disk and the like; and a communication section 507 including a network interface card such as a LAN card, a modem, and the like. The communication section 507 performs communication processing via a network such as the Internet.

In particular, according to an embodiment of the present disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product including a computer program tangibly embodied on a machine-readable medium, the computer program including program code for performing the methods shown in the flowcharts. In such an embodiment, the computer program can be loaded and installed through the communication section 507 .

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in a flowchart or block diagram may represent a module, program segment, or portion of code that contains one or more logic devices for implementing the specified Executable instructions for a function. It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or they may sometimes be executed in the reverse order, depending upon the functionality involved. It should also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by a dedicated hardware-based system that performs the specified functions or operations , or may be implemented by a combination of dedicated hardware and computer instructions.

The units involved in the embodiments described in the present application may be implemented by means of software or by means of hardware. The described units can also be set in the processor, for example, it can be described as: a controller includes a collection unit, a determination unit and a control unit. Among them, the names of these units do not constitute a limitation to the unit itself under certain circumstances. For example, the acquisition unit can also be described as "used to collect the flow of chilled water in the chilled water secondary pump system and the water supply terminal and units of the pressure value between the return ends".

As another aspect, the present application also provides a computer-readable storage medium, which may be the computer-readable storage medium contained in the device described in the above-mentioned embodiments; A computer-readable storage medium assembled in a terminal. The computer-readable storage medium stores one or more programs, and the programs are used by one or more processors to execute the control method of the chilled water secondary pump system described in this application.

The above description is only a preferred embodiment of the present application and an illustration of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solution formed by the specific combination of the above-mentioned technical features, but should also cover the technical solution formed by the above-mentioned technical features without departing from the inventive concept. Other technical solutions formed by any combination of or equivalent features thereof. For example, a technical solution formed by replacing the above-mentioned features with technical features with similar functions disclosed in (but not limited to) this application.

Claims (10)

1. a control method for chilled water secondary pumping system, described chilled water secondary pumping system bag Include for water end (W.E.), backwater end, be connected to described for the pipeline between water end (W.E.) and described backwater end and For at least one secondary pump driving chilled water to flow in described pipeline, it is characterised in that Described method includes:

Gather the flow of chilled water in chilled water secondary pumping system and described for water end (W.E.) with described Force value between backwater end；

Based on described for the pressure value difference between water end (W.E.) and described backwater end, described flow with preset The first impedance of described chilled water secondary pumping system, determine the number of secondary pump under running status Amount reference value；

Quantity based on the secondary pump under current operating conditions and described quantity reference value, control cold Freeze the operation of at least one secondary pump in water secondary pumping system.

Method the most according to claim 1, it is characterised in that described based on current operation The quantity of the secondary pump under state and described quantity reference value, control in chilled water secondary pumping system The operation of at least one secondary pump, including:

Judge the quantity of secondary pump under current operating conditions and described quantity reference value whether phase Deng；

If equal, then gather described confession water end (W.E.) and the freezing temperature angle value of described backwater end；

Based on the described chilled water temperature value difference for water end (W.E.) and described backwater end and freezing temperature angle value The preset range of difference, the running frequency of the secondary pump under regulation current operating conditions.

Method the most according to claim 2, it is characterised in that described method also includes:

Judge that whether the described chilled water temperature value difference for water end (W.E.) and backwater end is at described freezing temperature In the preset range of angle value difference；

If in the preset range of described chilled water temperature value difference, then increase the valve of regulation valve Aperture, described regulation valve is arranged in pipeline, for controlling the flow of chilled water in described pipeline.

Method the most according to claim 1, it is characterised in that described based on described water supply Pressure value difference, described flow and default described chilled water secondary between end and described backwater end First impedance of pumping system, determines the quantity reference value of secondary pump under running status, including:

The sum of the secondary pump included according to described chilled water secondary pumping system determines running status Under the span of secondary pump quantity；

Based on described pressure value difference, described flow, calculate in described span respectively each Second impedance of the described chilled water secondary pumping system that value is corresponding, obtains the set of the second impedance；

The set of described second impedance selects meet the second pre-conditioned impedance, described pre- If condition is arranged based on described first impedance；

The quantity of the secondary pump under running status corresponding for the second selected impedance is defined as fortune The quantity reference value of the secondary pump under row state.

Method the most according to claim 1, it is characterised in that described first impedance is base The secondary pump curve that includes in described chilled water secondary pumping system and pre-set.

6. a control device for chilled water secondary pumping system, described chilled water secondary pumping system bag Include for water end (W.E.), backwater end, be connected to described for the pipeline between water end (W.E.) and described backwater end and For at least one secondary pump driving chilled water to flow in described pipeline, it is characterised in that Described device includes:

Collecting unit, for gathering flow and the institute of the chilled water in chilled water secondary pumping system State for the force value between water end (W.E.) and described backwater end；

Determine unit, for based on described for water end (W.E.) and described backwater end between pressure value difference, Described flow and the first impedance of default described chilled water secondary pumping system, determine running status Under the quantity reference value of secondary pump；

Control unit, for quantity based on the secondary pump under current operating conditions and described quantity Reference value, the operation of at least one secondary pump in control chilled water secondary pumping system.

Device the most according to claim 6, it is characterised in that described control unit enters one Step is configured to:

Judge the quantity of secondary pump under current operating conditions and described quantity reference value whether phase Deng；

If equal, then gather described confession water end (W.E.) and the freezing temperature angle value of described backwater end；

Based on the described chilled water temperature value difference for water end (W.E.) and described backwater end and freezing temperature angle value The preset range of difference, the running frequency of the secondary pump under regulation current operating conditions.

Device the most according to claim 7, it is characterised in that described device also includes:

Regulation valve regulation unit, is configured to judge described confession water end (W.E.) and the freezing temperature of backwater end Whether angle value difference is in the preset range of described chilled water temperature value difference；If at described chilled water In the preset range of temperature value difference, then increasing the valve opening of regulation valve, described regulation valve is arranged In pipeline, for controlling the flow of chilled water in described pipeline.

Device the most according to claim 6, it is characterised in that described determine unit, bag Include:

Span determines module, is configured to include according to described chilled water secondary pumping system The sum of secondary pump determine the span of the secondary pump quantity under running status；

Computing module, is configured to, based on described pressure value difference, described flow, calculate institute respectively State the second impedance of described chilled water secondary pumping system corresponding to each value in span, Set to the second impedance；

Select module, be configured in the set of described second impedance selection and meet pre-conditioned The second impedance, described pre-conditioned based on described first impedance arrange；

Quantity reference value determines module, is configured to operation corresponding for the second selected impedance The quantity of the secondary pump under state is defined as the quantity reference value of the secondary pump under running status.

Device the most according to claim 6, it is characterised in that described first impedance is The secondary pump curve that includes based on described chilled water secondary pumping system and pre-set.