A cooling capacity scheduling method for a dual cooling source station

Abstract

The present invention proposes a cooling capacity dispatching method for a dual cold source station, and realizes cooling capacity dispatching between two cold source stations. The cold source station includes a water distributor, a water distributor main pipe, a water collector, a water collector main pipe, a cooling tower, a cooling water pump, a cooling valve, a refrigeration main unit, a freezing valve, and a freezing water pump, and is provided with an industrial control computer, a flow sensor, and a connecting pipe; the connecting pipe is used to connect the water distributors of the two cold source stations, and the water collectors of the two cold source stations; the flow sensors are respectively installed on the water distributor main pipes of the two cold source stations, and the middle position of the connecting pipe between the two water distributors; the industrial control computer collects the power information, evaporator temperature, condenser temperature, load rate, refrigeration power, and electric power of each refrigeration main unit and freezing water pump of the two cold source stations; the industrial control computer realizes cooling capacity dispatching of the two cold source stations by adjusting the freezing water pump frequency of the two cold source stations according to the collected information.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy management and control, and in particular relates to a cooling capacity scheduling method for a dual cooling source station. Background Art

[0002] A cold source station usually consists of a refrigeration main unit, a circulating water pump, a cooling tower, a water distributor, a water collector and terminal pipes. The refrigeration main unit, as the refrigeration equipment of the cold source station, is responsible for preparing low-temperature cold water. The circulating water pump is responsible for pushing the water to circulate in the pipes. The water distributor distributes the low-temperature water prepared by the refrigeration main unit to each cold end. The water collector collects the water flowing through each cold end and supplies it to the refrigeration main unit again for the next cycle.

[0003] When there are two cold source stations, the existing technology usually operates one cold source station as an independent system, lacking effective scheduling of the two cold source stations. Summary of the invention

[0004] In view of this, the present invention proposes a cooling capacity scheduling method for dual cooling source stations, which can not only realize cooling capacity scheduling between two cooling source stations to meet the cooling demand of the terminal, but also minimize the energy consumption of the system.

[0005] The specific technical solutions are as follows:

[0006] A cooling capacity dispatching system for a dual cooling source station includes two cooling source stations, wherein the cooling source stations include a water distributor, a water distributor main pipe, a water collector, a water collector main pipe, a cooling tower, a cooling water pump, a cooling valve, a refrigeration main unit, a freezing valve, and a freezing water pump. An industrial control computer, a flow sensor, and a connecting pipe are also provided; the connecting pipe is used to connect the water distributors of the two cooling source stations and the water collectors of the two cooling source stations respectively; the flow sensors are respectively installed on the water distributor main pipes of the two cooling source stations and the middle position of the connecting pipe between the two water distributors; the industrial control computer collects the power information, evaporator temperature, condenser temperature, load rate, cooling power, and electric power of each refrigeration main unit and freezing water pump of the two cooling source stations; the industrial control computer realizes the cooling capacity dispatching of the two cooling source stations by adjusting the freezing water pump frequency of the two cooling source stations according to the collected information. The cooling main unit includes an evaporator and a condenser.

[0007] A cooling capacity scheduling method for a dual cold source station is applied to a cooling capacity scheduling system for a dual cold source station. In each adjustment cycle, multiple scheduling flows are selected with a maximum schedulable flow as an upper limit, the total power consumption of the two cold source stations corresponding to each scheduling flow is estimated, the minimum value is selected from the current total power consumption and the estimated total power consumption, and the scheduling flow corresponding to the minimum value is used as the target flow of this adjustment to complete the scheduling, wherein the total power consumption of the cold source station includes the power consumption of all chilled water pumps in the cold source station and the power consumption of all refrigeration hosts, and the power consumption of the refrigeration host is obtained through a host energy efficiency distribution table.

[0008] Furthermore, a host energy efficiency distribution table of each refrigeration host in the cold source station is constructed respectively, and the host energy efficiency distribution table includes a horizontal axis, a vertical axis, and an energy efficiency ratio corresponding to (horizontal axis, vertical axis), wherein the horizontal axis is the temperature difference between the two devices, the vertical axis is the load rate corresponding to the current refrigeration host, and the energy efficiency ratio is the ratio of the refrigeration power corresponding to the current refrigeration host to the electric power; the temperature difference between the two devices refers to the difference between the evaporator temperature and the condenser temperature corresponding to the current refrigeration host.

[0009] Furthermore, the calculation method of the power consumption of the chilled water pump is: based on the power consumption of the chilled water pump measured in the previous adjustment cycle and the flow change coefficient corresponding to the current adjustment cycle, the power consumption of the chilled water pump in the current adjustment cycle is estimated using the similarity law principle of the chilled water pump.

[0010] Furthermore, during this adjustment period, the power consumption of the i-th chilled water pump The prediction formula is: ,in, is the power consumption of the i-th chilled water pump in the last regulation cycle, is the flow rate variation coefficient of the cold source station j corresponding to the i-th chilled water pump in this adjustment period.

[0011] Furthermore, during the adjustment period, the power consumption of the i-th refrigeration host at the cold source station j is The prediction methods include:

[0012] First, the flow change coefficient of cold source station j is used to predict the temperature difference between the two devices of the i-th refrigeration host of cold source station j after the flow change. , the specific formula is, ,in, It represents the temperature difference between the two devices of the i-th refrigeration host in the cold source station j before the flow changes;

[0013] Then, from the host energy efficiency distribution table of the i-th refrigeration host of the cold source station j, query the current load rate and the temperature difference between the two devices The energy efficiency ratio of the corresponding refrigeration host i ;

[0014] Finally, the power consumption of the future adjustment cycle is calculated by the energy efficiency ratio. ,in, is the cooling capacity of the i-th refrigeration host in the cold source station j in the last adjustment cycle, j=1,2.

[0015] Furthermore, the calculation formula of the flow variation coefficient of cold source station j is: , where j = 1, 2, is the current flow of cold source station j, For dispatching flow, when the flow from cold source station j increases, the dispatching flow changes positively, otherwise it changes negatively.

[0016] Furthermore, the maximum schedulable flow is the minimum value of the current flow of the two cold source stations measured by the flow sensor at the beginning of the regulation cycle.

[0017] The following beneficial effects can be achieved by adopting the present invention:

[0018] 1. By building connecting pipes, if a cold source station fails and cannot provide cooling, another cold source station can be dispatched to provide cooling to ensure the cooling demand at the terminal.

[0019] 2. By building connecting pipes, once the cooling capacity of a cold source station is insufficient, the spare host of another cold source station can be dispatched to provide cooling.

[0020] 3. The system of the present invention is easy to implement, has low transformation cost, and is convenient for engineering promotion.

[0021] 4. Through the method provided by the present invention, the connecting pipe can be used to dispatch the cold flow direction of the two cold source stations, and the system operation energy consumption is guaranteed to be the lowest while meeting the terminal energy demand, thus achieving a good energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a connection diagram of cold source station A and cold source station B;

[0023] Figure 2 This is a schematic diagram of the connection between the internal equipment of the cold source station;

[0024] Figure 3 The figure is a logical schematic diagram of the method of the present invention. DETAILED DESCRIPTION

[0025] Execution entity: Industrial control computer

[0026] The connection between cold source station A and cold source station B is as follows Figure 1 The connection diagram between the internal equipment of the cold source station is as shown in Figure 2 shown.

[0027] Install a flow sensor on the main pipe of the water distributor at cold source station A .

[0028] Install a flow sensor on the manifold of the water distributor at cold source station B .

[0029] The power information of each refrigeration host and chilled water pump in cold source station A is collected to the industrial control computer.

[0030] The power information of each refrigeration host and chilled water pump at cold source station B is collected to the industrial control computer.

[0031] The evaporator temperature, condenser temperature, load rate, cooling power and electric power of each refrigeration host in the cold source station A are collected and sent to the industrial control computer.

[0032] The evaporator temperature, condenser temperature, load rate, cooling power and electric power of each refrigeration host in the cold source station B are collected to the industrial control computer.

[0033] Connect the water distributors of cold source station A and cold source station B with connecting pipe F.

[0034] Connect the water collectors of cold source station A and cold source station B with connecting pipe J.

[0035] Install a flow sensor with flow detection function in the middle of the connecting pipe F. .

[0036] The present invention generates a frequency difference by controlling the operating frequency of the chilled water pumps of the cold source station A and the cold source station B. When the operating frequency of the chilled water pump of the cold source station A is greater than that of the cold source station B, the pressure difference caused by the frequency difference enables the cold capacity of the cold source station A to be dispatched to the cold source station B; when the operating frequency of the chilled water pump of the cold source station B is greater than that of the cold source station A, the pressure difference caused by the frequency difference enables the cold capacity of the cold source station B to be dispatched to the cold source station A.

[0037] When the refrigeration host is running, the industrial control computer will collect the evaporator temperature, condenser temperature, load rate, refrigeration and cooling, and electric power data of the refrigeration host to build a data model. A two-dimensional host energy efficiency distribution table is established with the temperature difference between the two devices (i.e. the difference between the evaporator temperature and the condenser temperature) as the horizontal axis and the load rate as the vertical axis. The ratio of refrigeration power to electric power is the energy efficiency ratio, and the energy efficiency ratio corresponding to the temperature difference between the two devices and the load rate is filled in the table.

[0038] Take two minutes (default value, adjustable) as an adjustment cycle, repeat the iterative evolution cycle, and execute the following method steps.

[0039] Calculate the temperature difference between the two devices of each refrigeration host in the two cold source stations.

[0040] Record the current flow in the manifolds of the two cold source stations;

[0041] Calculate the total power consumption of each refrigeration host in the two cold source stations during the regulation period;

[0042] Calculate the cooling capacity of each refrigeration host in the two cold source stations during the adjustment period;

[0043] Calculate the total current power consumption of each chilled water pump in the two cold source stations during the regulation period;

[0044] Take the minimum value of the current flow in the water distributor main pipe of the two cold source stations as the maximum dispatchable flow, denoted as ;

[0045] Taking the set flow change as a step, the power consumption after the 16-step flow change is calculated in multiple steps respectively. Combined with the current power consumption, a total of 17 estimated power consumptions are obtained. The flow corresponding to the minimum value of the 17 estimated power consumptions is taken as the target flow for this adjustment.

[0046] Step 1:

[0047] Calculate the temperature difference between the two devices of each refrigeration host in the cold source station A and record them as , … .

[0048] Record the flow sensor of cold source station A The current flow rate.

[0049] Calculate the power consumption of each refrigeration host in the cold source station A during the adjustment period and record them as , … .

[0050] Calculate the total power usage of the host .

[0051] Calculate the cooling capacity of each refrigeration host in the cold source station A during the adjustment period and record them as , … .

[0052] Calculate the total current power consumption of each chilled water pump in the cold source station A during the regulation period, recorded as .

[0053] Step 2:

[0054] Calculate the temperature difference between the two devices of each refrigeration host in the cold source station B and record them as , … .

[0055] Record the flow sensor of cold source station B The current flow rate.

[0056] Calculate the power consumption of each refrigeration host in the cold source station B during the adjustment period and record them as , … .

[0057] Calculate the total power usage of the host .

[0058] Calculate the cooling capacity of each refrigeration host in the cold source station B during the adjustment period and record them as , … .

[0059] Calculate the total current power consumption of each chilled water pump in the cold source station B during the regulation period, and record it as .

[0060] Step 3:

[0061] Pick and The minimum value of is taken as the maximum dispatchable flow, denoted as .

[0062] Step 4:

[0063] exist On the basis of , a 5% flow change is a step, from 5% to 40%, the flow from cold source station A to cold source station B is recorded as a positive change, and the flow from cold source station B to cold source station A is recorded as a negative change, with a total of 16 step flow changes. The power consumption after these 16 steps of flow changes is calculated respectively, and combined with the current power consumption, a total of 17 estimated power consumptions are obtained. The flow corresponding to the minimum value of the 17 estimated power consumptions is taken as the target flow for this adjustment.

[0064] The calculation process of electricity consumption is explained by taking the 5% change in flow from cold source station A to cold source station B as an example.

[0065] Calculate the scheduled traffic .

[0066] Flow variation coefficient of cold source station A .

[0067] Flow variation coefficient of cold source station B .

[0068] The current power consumption of the chilled water pump at the known cold source station A and flow rate variation coefficient In the case of the similarity law of the chilled water pump, the power consumption of the chilled water pump in the next cycle after the flow rate changes can be calculated. Cold source station B uses the same algorithm to calculate the power consumption of the chilled water pump in the next cycle .

[0069] Calculate the power consumption of each refrigeration host in cold source station A and cold source station B in the next cycle after the flow changes.

[0070] Calculate the temperature difference between the two devices after the flow rate changes .

[0071] Query the current load rate and the temperature difference between the two devices from the host energy efficiency distribution table The corresponding energy efficiency ratio . The power consumption of the next cycle can be calculated by the energy efficiency ratio. The electricity consumption calculation method for other refrigeration hosts before the next week is the same.

[0072] Calculate the power consumption of the refrigeration host of cold source station A in the next cycle .

[0073] Calculate the power consumption of the refrigeration host of cold source station B in the next cycle .

[0074] Calculate the total energy consumption of this step flow change .

[0075] Repeat this step to calculate the total energy consumption corresponding to different adjustment flow rates. , , , , , , , , , , , , , ,

[0076] Step 5:

[0077] Compare the 16 estimated energy consumptions in step 4 with the current energy consumption, and take the flow with the minimum energy consumption as the target adjustment flow, recorded as .

[0078] Step 6:

[0079] Detect the current connecting pipe flow Whether the target flow rate is met , if the current connecting pipe flow > , then gradually reduce the chilled water pump frequency of cold source station A, and gradually increase the chilled water pump frequency of cold source station B until the flow rate meets the target regulation flow rate .

[0080] Detect the current connecting pipe flow Whether the target flow rate is met , if the current connecting pipe flow < , then gradually increase the chilled water pump frequency of cold source station A, and gradually reduce the chilled water pump frequency of cold source station B until the flow meets the target regulation flow .

[0081] The overall logic of the present invention is as follows Figure 3 shown.

Claims

1. A cooling capacity scheduling method for a dual cooling source station, characterized in that: In each adjustment cycle, multiple dispatching flows are selected with the maximum dispatchable flow as the upper limit, and the total power consumption of the two cold source stations corresponding to each dispatching flow is estimated. The minimum value is selected from the current total power consumption and the estimated total power consumption, and the dispatching flow corresponding to the minimum value is used as the target flow of this adjustment to complete the dispatching. Among them, the total power consumption of the cold source station includes the power consumption of all chilled water pumps in the cold source station and the power consumption of all refrigeration hosts. The power consumption of the refrigeration host is obtained through the host energy efficiency distribution table; in this adjustment cycle, the power consumption of the i-th chilled water pump The prediction formula is: ,in, is the power consumption of the i-th chilled water pump in the last regulation cycle, is the flow rate variation coefficient of the cold source station j corresponding to the i-th chilled water pump in this adjustment period; The power consumption of the i-th refrigeration host at the cold source station j during the adjustment period The prediction methods include: First, the flow change coefficient of cold source station j is used to predict the temperature difference between the two devices of the i-th refrigeration host of cold source station j after the flow change. , the specific formula is, ,in, It represents the temperature difference between the two devices of the i-th refrigeration host in the cold source station j before the flow changes; Then, from the host energy efficiency distribution table of the i-th refrigeration host of the cold source station j, query the current load rate and the temperature difference between the two devices The energy efficiency ratio of the corresponding refrigeration host i ; Finally, the power consumption of the future adjustment cycle is calculated by the energy efficiency ratio. ,in, is the cooling capacity of the i-th refrigeration host of the cold source station j in the last adjustment cycle, j=1, 2; The calculation formula for the flow variation coefficient of cold source station j is: , where j = 1, 2, is the current flow of cold source station j, For dispatching flow, when the flow from cold source station j increases, the dispatching flow changes positively, otherwise it changes negatively; The maximum dispatchable flow is the minimum value of the current flow of the two cold source stations measured by the flow sensor at the beginning of the regulation cycle.

2. The cooling capacity scheduling method for a dual cooling source station according to claim 1, characterized in that: A host energy efficiency distribution table for each refrigeration host in the cold source station is constructed respectively, and the host energy efficiency distribution table includes a horizontal axis, a vertical axis, and an energy efficiency ratio corresponding to the horizontal axis and the vertical axis, wherein the horizontal axis is the temperature difference between the two devices, the vertical axis is the load rate corresponding to the current refrigeration host, and the energy efficiency ratio is the ratio of the refrigeration power corresponding to the current refrigeration host to the electric power; the temperature difference between the two devices refers to the difference between the evaporator temperature and the condenser temperature corresponding to the current refrigeration host.

3. The cooling capacity scheduling method for a dual cooling source station according to claim 1, characterized in that: The calculation method of the power consumption of the chilled water pump is as follows: based on the power consumption of the chilled water pump measured in the previous adjustment cycle and the flow change coefficient corresponding to the current adjustment cycle, the power consumption of the chilled water pump in the current adjustment cycle is estimated using the similarity law principle of the chilled water pump.

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