Cooling tower active optimization control method and control system based on energy efficiency of refrigeration plant system

Abstract

The present application relates to the central air conditioning automatic control technical field, and more particularly to the cooling tower active optimization control method and control system based on the refrigeration machine room system energy efficiency, including the following steps: step 1, the cooling tower is in the initial operation number, after the fluctuation of refrigeration machine room system energy efficiency tends to be stable, the current state of cooling tower wet ball approximation degree K1 and refrigeration machine room system energy efficiency data SCOP1 are obtained.The present application judges to increase or reduce the use amount of cooling tower through the wet ball approximation degree of cooling tower when the system is running, and after each adjustment, the ratio of the chilled water cooling capacity in the chilled water circuit to the total energy consumption of the system is judged, if the adjusted ratio is greater than the adjusted ratio, it proves that the energy efficiency ratio of the system is higher after adjustment, otherwise, the adjustment is invalid and is withdrawn, through continuous adjustment, the maximum refrigeration effect is achieved with the minimum energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of central air-conditioning automatic control, and more particularly to an active optimization control method and a control system for a cooling tower based on the energy efficiency of a refrigeration machine room system. Background Art

[0002] In the design of cooling towers for central water-cooled chiller air-conditioning systems in commercial buildings, common designs are composed of multiple groups of multiple cooling towers. In actual applications, generally, a certain number of cooling towers are started according to the number of operating chillers, or the start and stop of the cooling towers are controlled according to the outlet water temperature of the cooling towers, without an energy efficiency optimization control concept.

[0003] Therefore, the present invention aims to improve the energy efficiency ratio of the system by optimizing the control of the cooling tower with the energy efficiency of the refrigeration machine room system as the goal, ultimately reducing the operating cost and meeting the requirements of green energy and sustainable development. Summary of the Invention

[0004] In view of the technical problems existing in the control of central air-conditioning cooling towers in the prior art, the first aspect of the present invention provides an active optimization control method for a cooling tower based on the energy efficiency of a refrigeration machine room system, including the following steps:

[0005] Step 1: When the cooling tower is operating at the initial number of units, after the fluctuation of the energy efficiency of the refrigeration machine room system tends to be stable, obtain the wet-bulb approach K1 of the cooling tower and the energy efficiency data SCOP1 of the refrigeration machine room system in the current state;

[0006] Step 2: Compare the size of the wet-bulb approach K1 of the cooling tower in the current state with the designed wet-bulb approach K0 of the cooling tower;

[0007] Step 3: Adjust the number of cooling towers: If the wet-bulb approach K1 of the cooling tower is greater than the designed wet-bulb approach K0 of the cooling tower, increase the number of cooling towers; if the wet-bulb approach K1 of the cooling tower is less than the designed wet-bulb approach K0 of the cooling tower, reduce the number of cooling towers;

[0008] Step 4: After waiting for the fluctuation of the energy efficiency of the refrigeration machine room system to tend to be stable again, obtain the current energy efficiency data SCOP2 of the refrigeration machine room system;

[0009] Step 5: Compare the energy efficiency data SCOP1 of the refrigeration machine room system in Step 1 with the energy efficiency data SCOP2 of the refrigeration machine room system in Step 4. If SCOP2 > SCOP1, determine that the adjustment of the number of cooling towers in Step 3 is an effective adjustment, and return to Step 1 to continue the next adjustment; if SCOP2 < SCOP1, determine that the adjustment of the number of cooling towers in Step 3 is an ineffective adjustment, and revoke the adjustment behavior of the number of cooling towers in Step 3.

[0010] Preferably, the wet-bulb approach K of the cooling tower = T4 - Tw;

[0011] Where T4 is the outlet water temperature of the cooling tower, and Tw is the wet-bulb temperature under the current environment.

[0012] Preferably, the outlet water temperature of the cooling tower is obtained by installing a temperature sensor on the cooling water outlet pipe of the cooling tower.

[0013] Preferably, by setting up a temperature and humidity sensor outdoors, the outdoor temperature T and outdoor humidity RH% are obtained, and the wet-bulb temperature Tw under the current environment is calculated as follows: Tw = T × arctan[0.151977 × (RH% + 8.313659)^(1 / 2)] + arctan(T + RH%) - arctan(RH% - 1.676331) + 0.00391838 × (RH%)^(3 / 2) × arctan(0.023101 × RH%) - 4.686035.

[0014] Preferably, the energy efficiency data for the chiller room system is SCOP = E1 / P. 总 ;

[0015] Where E1 is the chilled water cooling capacity, P 总 It is the total power of the system, including the total power of the chiller, chilled water pump, cooling pump, and cooling tower.

[0016] Preferably, the chilled water cooling capacity E1 = (T2 - T1) * F1 * K;

[0017] Where T2 is the return temperature of chilled water in the chilled water circuit, T1 is the supply temperature of chilled water in the chilled water circuit, F1 is the flow rate of chilled water in the chilled water circuit, and K is the specific heat capacity coefficient of water, which is determined according to the actual water temperature.

[0018] Preferably, in step 3, the method for adjusting the number of cooling towers is to make a direct proportional conversion based on the number of remaining cooling towers and the wet-bulb approximation margin (K1-K0), and each loading does not exceed 1 / 3 of the total number of remaining cooling towers.

[0019] Preferably, in step 3, the adjustment method for reducing the number of cooling towers is: to perform an inverse proportional conversion based on the number of operating cooling towers and the wet-bulb approximation margin (K1-K0), and to reduce the load by no more than 2 cooling towers each time.

[0020] Preferably, the condition for the energy efficiency fluctuation of the chiller room system to stabilize is that the energy efficiency fluctuation of the chiller room system is stabilized within ±0.2.

[0021] The second aspect of this invention proposes a technical solution: an active optimization control system for cooling towers based on the energy efficiency of a refrigeration room system, comprising:

[0022] The chiller has a chilled water circuit connected to one side of its evaporator and a cooling water circuit connected to one side of its condenser.

[0023] Multiple chilled water pumps are connected in parallel to the chilled water circuit to control the flow rate of chilled liquid in the chilled water circuit;

[0024] Multiple cooling pumps are connected in parallel to the cooling water circuit to control the flow rate of coolant in the cooling water circuit;

[0025] Multiple cooling towers are connected to the cooling water circuit to cool the cooling water passing through the cooling towers;

[0026] The data acquisition component is used to collect data on the chilled water circuit, including chilled fluid supply temperature, chilled fluid return temperature, chilled fluid flow rate, total system operating power, outdoor temperature, and humidity.

[0027] The controller, based on the data acquired by the data acquisition unit, controls the number of cooling towers in operation according to the control method described above.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] This invention determines whether to increase or decrease the amount of cooling tower used by measuring the wet-bulb approximation of the cooling tower during system operation. After each adjustment, it judges the ratio of chilled water cooling capacity in the chilled water circuit to the total energy consumption of the system. If the adjusted ratio is greater than the original ratio, it proves that the adjustment has improved the system's energy efficiency ratio; otherwise, the adjustment is invalid and withdrawn. Through continuous adjustments, the relationship between the system's cooling effect and the total system power is balanced, so that the ratio of the system's cooling effect to the total system power is at its maximum value. This achieves the maximum cooling effect with the minimum energy consumption. Attached Figure Description

[0030] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0031] Figure 1 This is a flowchart of the active optimization control method for cooling towers based on the energy efficiency of refrigeration room systems, as shown in this invention.

[0032] Figure 2 This is a schematic diagram of the active optimization control system for cooling towers based on the energy efficiency of a refrigeration room system, as shown in this invention.

[0033] Figure 3 This is a schematic diagram of the power distribution system shown in this invention for obtaining the total system power. Detailed Implementation

[0034] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0035] It should be understood that the cooling tower in this application refers in particular to a water-cooled cooling tower. The purpose of a cooling tower is to cool and reduce the temperature of the cooling water in the cooling water circuit. The principle of cooling is that the cooling water is sprayed into the air to allow the cooling water itself to evaporate. Evaporation absorbs heat, thereby lowering the temperature of the remaining cooling water. This evaporation process usually has a mass loss of 1-3% (based on flow rate calculation, including drift and other factors).

[0036] In the above process, since high-temperature water is continuously injected into the cooling tower, the cooling effect of the cooling tower on the cooling water is obviously limited. The larger the volume of the cooling tower, the better the cooling effect. However, when the volume of the cooling tower is fixed, the cooling effect of the cooling tower can be represented by the approaching temperature.

[0037] Among them, Approaching Temperature refers to the difference between the outlet water temperature and the wet-bulb temperature of the cooling tower. The wet-bulb temperature refers to the temperature of a surface above the water after the water has been fully and naturally evaporated and dissipated heat.

[0038] Generally, cooling towers have design parameters. For example, the design approximation of a typical cooling tower is 4°C, meaning the temperature of the cooling water exiting the tower is 4°C higher than the wet-bulb temperature. The fewer cooling towers used, the more water each tower needs to cool. Due to limited cooling capacity, a higher exit temperature results in a higher actual wet-bulb approximation, leading to a higher temperature supplied to the air conditioning unit. This can reduce the cooling effect of the air conditioner. Increasing the number of cooling towers can achieve better cooling, but also higher energy efficiency. Therefore, this application aims to address the optimal balance between energy efficiency and cooling performance.

[0039] [Active Optimization Control Method for Cooling Towers Based on Energy Efficiency of Refrigeration Room Systems]

[0040] Combination Figure 1 As shown, the first aspect of the present invention proposes an active optimization control method for cooling towers based on the energy efficiency of a refrigeration room system, comprising the following steps:

[0041] Step 1: With the initial number of cooling towers in operation, after the fluctuation of the energy efficiency of the chiller room system tends to stabilize, obtain the cooling tower wet-bulb approximation K1 and the chiller room system energy efficiency data SCOP1 under the current state;

[0042] Step 2: Compare the wet bulb approach K1 of the cooling tower in the current state with the designed wet bulb approach K0 of the cooling tower.

[0043] Step 3: Adjust the number of cooling towers. If the wet bulb approach K1 of the cooling tower is greater than the designed wet bulb approach K0 of the cooling tower, increase the number of cooling towers. If the wet bulb approach K1 of the cooling tower is less than the designed wet bulb approach K0 of the cooling tower, reduce the number of cooling towers.

[0044] Step 4: Wait until the fluctuations in the energy efficiency of the refrigeration machine room system tend to stabilize again, and obtain the current energy efficiency data SCOP2 of the refrigeration machine room system.

[0045] Step 5: Compare the energy efficiency data SCOP1 of the refrigeration machine room system in Step 1 with the energy efficiency data SCOP2 of the refrigeration machine room system in Step 4. If SCOP2 > SCOP1, determine that the adjustment of the number of cooling towers in Step 3 is an effective adjustment, and return to Step 1 to continue the next adjustment. If SCOP2 < SCOP1, determine that the adjustment of the number of cooling towers in Step 3 is an ineffective adjustment, and cancel the adjustment action of the number of cooling towers in Step 3.

[0046] In a specific embodiment, first calculate the current energy efficiency data SCOP1 of the refrigeration machine room system:

[0047] The energy efficiency data SCOP of the refrigeration machine room system = E1 / P 总 ;

[0048] where E1 is the chilled water cooling capacity, and P 总 is the total system power, including the sum of the powers of the chiller, chilled water pump, cooling water pump, and cooling tower.

[0049] In a specific embodiment, install intelligent electricity meters in the power distribution circuits of the chiller, chilled water pump, cooling water pump, and cooling tower, calculate the powers of the chiller + chilled water pump + cooling water pump + cooling tower, and obtain the total system power P 总 。

[0050] In a specific embodiment, the chilled water cooling capacity E1 = (T2 - T1) * F1 * K;

[0051] where T2 is the return water temperature of the chilled water in the chilled water circuit, T1 is the supply water temperature of the chilled water in the chilled water circuit, F1 is the flow rate of the chilled water in the chilled water circuit, and K is the specific heat capacity coefficient of water, which is determined according to the actual water temperature. The above return water temperature T2 of the chilled water, supply water temperature T1 of the chilled water, and flow rate F1 of the chilled water can be obtained through the instruments installed on the pipeline, and thus the chilled water cooling capacity E1 can be obtained.

[0052] By regarding the above chilled water cooling capacity E1 and total system power P 总The ratio is used to obtain the current energy efficiency data (SCOP1) of the chiller room system, and the current energy efficiency data (SCOP1) of the chiller room system is recorded.

[0053] Next, calculate the current wet-bulb approximation K1 of the cooling tower:

[0054] The wet-bulb approximation of the cooling tower is K = T4 - Tw; where T4 is the outlet water temperature of the cooling tower and Tw is the wet-bulb temperature under the current environment.

[0055] Optionally, the outlet water temperature of the cooling tower can be obtained by installing a temperature sensor on the cooling water outlet pipe of the cooling tower.

[0056] Preferably, by setting up a temperature and humidity sensor outdoors, the outdoor temperature T and outdoor humidity RH% are obtained, and the wet-bulb temperature Tw under the current environment is calculated as follows: Tw = T × arctan[0.151977 × (RH% + 8.313659)^(1 / 2)] + arctan(T + RH%) - arctan(RH% - 1.676331) + 0.00391838 × (RH%)^(3 / 2) × arctan(0.023101 × RH%) - 4.686035.

[0057] Thus, the current wet-bulb approximation K1 of the cooling tower is obtained through the data collected above.

[0058] Next, compare the current wet-bulb approximation K1 of the cooling tower with the designed wet-bulb approximation K0. If the current wet-bulb approximation K1 > K0, then the number of operating cooling towers needs to be increased. After increasing the number of cooling towers, wait for the system energy efficiency fluctuations to stabilize, and then calculate the SCOP2 energy efficiency data of the chiller room system after adjusting the number of cooling towers according to the above method. If SCOP2 is greater than SCOP1, then the adjustment is effective and the above scheme can be continued. If SCOP2 is less than SCOP1, then the adjustment is ineffective and the intervention on the number of operating cooling towers is withdrawn. Wait for the operating conditions of the chiller unit of the system to change before making the next adjustment.

[0059] Among them, when the energy efficiency fluctuation of the refrigeration room system is stable within ±0.2, the system energy efficiency fluctuation is considered to be in a stable state.

[0060] In an optional embodiment, in step 3, the adjustment method for increasing the number of cooling towers is: to make a direct proportional conversion based on the number of remaining cooling towers and the wet-bulb approximation margin (K1-K0), and to load no more than 1 / 3 of the total number of cooling towers each time.

[0061] Specifically, the number of cooling towers to be adjusted next time is X = (remaining number of cooling towers) * (K1 - K0) / K0. X is rounded to the nearest integer to be the actual number to be adjusted next time. When X > (total number of cooling towers * 1 / 3), X = (total number of cooling towers * 1 / 3); when X < 1, X = 1.

[0062] In other embodiments, in step 3, the adjustment method for increasing the number of cooling towers can also be to increase them by a fixed amount each time, such as adding one unit each time.

[0063] In an optional embodiment, in step 3, the adjustment method for reducing the number of cooling towers is: to perform an inverse proportional conversion based on the number of operating cooling towers and the wet-bulb approximation margin (K1-K0), and to reduce the load by no more than 2 cooling towers each time.

[0064] Specifically, the number of cooling towers to be adjusted next time is X = (number of cooling towers in operation) * (K0 - K1) / K0. X is rounded to the nearest integer to be the actual number to be adjusted next time. When X > 2, X = 2; when X < 1, X = 1.

[0065] In other embodiments, in step 3, the adjustment method for increasing the number of cooling towers can also be to reduce them by a fixed amount each time, for example, reducing one unit each time.

[0066] In this way, by making fine adjustments each time, the relationship between the system's cooling effect and the total system power is balanced, so that the ratio of the system's cooling effect to the total system power is at its maximum value. This allows the system to achieve the maximum cooling effect with the minimum energy consumption.

[0067] Active optimization control system for cooling towers based on energy efficiency of refrigeration room systems

[0068] Combination Figure 2 As shown, the second aspect of the present invention proposes a technical solution: a cooling tower active optimization control system based on the energy efficiency of a refrigeration room system, comprising:

[0069] The chiller 10 has a chilled water circuit connected to one side of the evaporator and a cooling water circuit connected to one side of the condenser.

[0070] Multiple chilled water pumps 20 are connected in parallel to the chilled water circuit to control the flow rate of chilled liquid in the chilled water circuit;

[0071] Multiple cooling pumps 30 are connected in parallel to the cooling water circuit to control the flow rate of coolant in the cooling water circuit.

[0072] Multiple cooling towers 40 are connected to the cooling water circuit to cool the cooling water passing through the cooling towers 40;

[0073] The data acquisition component is used to collect data on the chilled water circuit, including chilled fluid supply temperature, chilled fluid return temperature, chilled fluid flow rate, total system operating power, outdoor temperature, and humidity.

[0074] The controller controls the number of operating cooling towers 40 according to the data acquired by the data acquisition unit and the control method described above.

[0075] Combination Figure 2 As shown, with the chiller unit 10 as the boundary, the circuit to the right of the chiller unit 10 is the chilled water circuit, and the circuit to the left of the chiller unit 10 is the cooling water circuit.

[0076] In the chilled water circuit, the chilled water supply pipe 101 is connected to the water distributor, which is connected to the user. The other end of the water distributor is the water collector, which is connected to the chilled water return pipe 102 and then to the chiller 10. A chilled water supply temperature sensor is installed on the chilled water supply pipe 101, and a chilled water return temperature sensor and a chilled water flow sensor are installed on the chilled water return pipe 102.

[0077] The chilled water cooling capacity E1 can be obtained through chilled water supply temperature sensor, return water temperature sensor, and chilled water flow sensor.

[0078] The first end of the cooling water supply pipeline 201 is connected to the chiller 10, and the second end is connected to multiple cooling towers. The first end of the cooling water return pipeline 202 is connected to the cooling tower, and the second end is connected to the chiller 10 through the cooling pump 30, forming a closed loop.

[0079] Combination Figure 3 As shown, smart meters are installed in the power distribution circuits of the chiller, chilled water pump, cooling water pump, and cooling tower to calculate the power of the chiller + chilled water pump + cooling water pump + cooling tower, thus obtaining the total system power P. 总 .

[0080] Based on the parameters collected by the aforementioned sensors, the controller controls the number of cooling towers to be turned on according to the aforementioned active optimization control method for cooling towers. This balances the relationship between the system's cooling effect and the total system power, ensuring that the ratio of the system's cooling effect to the total system power is at its maximum value. This achieves the maximum cooling effect with the minimum energy consumption.

[0081] Specifically, each time the system runs, the system sets an initial number of cooling towers to operate based on the outdoor temperature and the number of operating units of the main engine, and activates the corresponding number of cooling towers. After waiting for the system to reach a stable state (the fluctuation of the energy efficiency of the refrigeration machine room system is stable within ±0.2) and lasting for a certain period of time, record the current energy efficiency data of the refrigeration machine room system as the energy efficiency SCOP1 of the refrigeration machine room system. Then record the current wet bulb approach of the system as K1. If the current wet bulb approach K1 > K0, increase the number of operating cooling towers, and make a proportional conversion based on the number of remaining cooling towers and the wet bulb approach margin (K1 - K0), with each load addition not exceeding 1 / 3 of the number of remaining cooling towers. If the current wet bulb approach K1 < K0, reduce the number of operating cooling towers, and make an inverse conversion based on the number of operating cooling towers and the wet bulb approach margin (K1 - K0), with each load reduction not exceeding 2 cooling towers.

[0082] Then wait again for the system to reach a stable state (the fluctuation of the energy efficiency of the refrigeration machine room system is stable within ±0.2) and last for a certain period of time, and record the current energy efficiency data of the refrigeration machine room system as the energy efficiency SCOP2 of the refrigeration machine room system. Then judge the impact of the operation of reducing or increasing the cooling towers this time on the energy efficiency of the refrigeration machine room system of the system. If the energy efficiency SCOP2 of the refrigeration machine room system > the energy efficiency SCOP1 of the refrigeration machine room system, it is considered that this adjustment is effective, and then continue with the next adjustment. If the energy efficiency SCOP2 of the refrigeration machine room system < the energy efficiency SCOP1 of the refrigeration machine room system, it is considered that this adjustment is ineffective, revoke this adjustment, and wait for the operating conditions of the chilled water main engine of the system to change before making the next adjustment.

[0083] Combined with the above embodiments, the present invention determines whether to increase or decrease the usage of cooling towers through the wet bulb approach of the cooling towers during system operation. And after each adjustment, by judging the ratio of the chilled water cooling capacity in the chilled water circuit to the total energy consumption of the system, if the ratio after adjustment is greater than the ratio before adjustment, it proves that the energy efficiency ratio of the system is higher after adjustment, otherwise the adjustment is ineffective and withdrawn. Through continuous adjustment, the relationship between the system cooling effect and the total system power is balanced, so that the ratio of the system cooling effect to the total system power is in the maximum state, thus achieving the maximum cooling effect with the minimum energy consumption.

[0084] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by what is defined in the claims.

Claims

1. A cooling tower active optimization control method based on the energy efficiency of a chiller plant system, characterized in that, The method comprises the following steps: Step 1, obtaining the cooling tower wet bulb approximation degree K1 and the refrigeration plant system energy efficiency data SCOP1 under the current state after the fluctuation of the refrigeration plant system energy efficiency tends to be stable under the initial number of running cooling towers; Step 2, comparing the cooling tower wet bulb approximation degree K1 and the cooling tower design wet bulb approximation degree K0 under the current state; Step 3, adjusting the number of cooling towers: if the cooling tower wet bulb approximation degree K1 is greater than the cooling tower design wet bulb approximation degree K0, the number of cooling towers is increased, and if the cooling tower wet bulb approximation degree K1 is less than the cooling tower design wet bulb approximation degree K0, the number of cooling towers is reduced; Step 4, obtaining the current refrigeration plant system energy efficiency data SCOP2 after the fluctuation of the refrigeration plant system energy efficiency tends to be stable again; Step 5, comparing the refrigeration plant system energy efficiency data SCOP1 in step 1 and the refrigeration plant system energy efficiency data SCOP2 in step 4, if SCOP2>SCOP1, it is determined that the adjustment of the number of cooling towers in step 3 is effective adjustment, and the next adjustment is continued in step 1, if SCOP2<SCOP1, it is determined that the adjustment of the number of cooling towers in step 3 is invalid adjustment, and the adjustment of the number of cooling towers in step 3 is cancelled.

2. The chilled water plant system energy efficiency based cooling tower active seeking optimal control method of claim 1, wherein, The cooling tower wet bulb approximation degree K=T4-Tw; Wherein, T4 is the outlet water temperature of the cooling tower, and Tw is the wet bulb temperature under the current environment.

3. The chilled water plant system energy efficiency based cooling tower active optimization control method of claim 2, wherein, The outlet water temperature of the cooling tower is obtained by setting a temperature sensor on the cooling water outlet pipe of the cooling tower.

4. The chilled water plant system energy efficiency based cooling tower active optimization control method of claim 2, wherein, The outdoor temperature T and the outdoor humidity RH% are obtained by setting a temperature and humidity sensor outdoors, and the wet bulb temperature Tw under the current environment is Tw=T×arctan[0.151977×(RH%+8.313659)^(1 / 2)]+arctan(T+RH%)-arctan(RH%-1.676331)+0.00391838×(RH%)^(3 / 2)×arctan(0.023101×RH%)-4.686035.

5. The chilled water plant system energy efficiency based cooling tower active seeking optimal control method of claim 1, wherein, Refrigeration plant system energy efficiency data SCOP = E1 / P 总 ; Wherein, E1 is the refrigeration water cooling capacity, P 总 is the total power of the system, including the power sum of the cold water main + refrigeration pump + cooling pump + cooling tower.

6. The chilled water plant system energy efficiency based cooling tower active seeking optimal control method of claim 5, wherein, The refrigerated water cooling capacity E1=(T2-T1)*F1*K; Wherein, T2 is the return water temperature of the refrigerated water in the refrigerated water circuit, T1 is the supply water temperature of the refrigerated water in the refrigerated water circuit, F1 is the flow of the refrigerated water in the refrigerated water circuit, and K is the specific heat capacity coefficient of water, which is determined according to the actual water temperature.

7. The chilled water plant system energy efficiency based cooling tower active seeking optimal control method of claim 1, wherein, In step 3, the adjustment mode of increasing the number of cooling towers is: according to the proportion conversion of the remaining number of cooling towers and the wet bulb approximation degree margin (K1-K0), no more than 1 / 3 of the remaining number of cooling towers is loaded each time.

8. The chilled water plant system energy efficiency based cooling tower active seeking optimal control method of claim 1, wherein, In step 3, the adjustment mode of reducing the number of cooling towers is: according to the inverse proportion conversion of the number of running cooling towers and the wet bulb approximation degree margin (K1-K0), no more than 2 cooling towers are unloaded each time.

9. The chilled water plant system energy efficiency based cooling tower active seeking optimal control method of claim 1, wherein, The condition that the fluctuation of the refrigeration plant system energy efficiency tends to be stable is that the fluctuation of the refrigeration plant system energy efficiency is stable within ±0.

2.

10. A cooling tower active optimization control system based on chiller plant system energy efficiency, characterized in that, It comprises: A chilled water main unit (10), one side of the evaporator of the chilled water main unit (10) is connected with a refrigerated water circuit, and one side of the condenser of the chilled water main unit (10) is connected with a cooling water circuit; a plurality of chilled water pumps (20) connected in parallel to the chilled water circuit for controlling the chilled water flow rate in the chilled water circuit; a plurality of cooling water pumps (30) connected in parallel to the cooling water circuit for controlling the cooling water flow rate in the cooling water circuit; a plurality of cooling towers (40) connected to the cooling water circuit for cooling the cooling water passing through the cooling towers (40); a data acquisition unit for acquiring the chilled water supply temperature, the chilled water return temperature, the chilled water flow rate, the total system operating power, the outdoor temperature and the humidity in the chilled water circuit; a controller for controlling the number of operating cooling towers (40) according to the data acquired by the data acquisition unit and according to the control method of any one of claims 1-9.

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