Disclosure of Invention
The embodiment of the invention aims to provide a method and a device for controlling a cooling water system of a central air conditioner and the central air conditioner.
In order to achieve the above object, an embodiment of the present invention provides a method for controlling a cooling water system of a central air conditioner, where the central air conditioner includes a cooling tower, a cooling water pump, and a water chiller, and the method includes: establishing a curve database according to performance parameters of equipment of the cooling water system, wherein the curve comprises curves related to the power of the water chilling unit, the power of the cooling water pump and the power of a fan of the cooling tower; determining the total cold source power P according to each of the n sets of performance data and the curve of the curve databasen(ii) a With the determined n total cold source powers PnThe performance data corresponding to the minimum value in (1) controls the operation of the cooling water system, wherein n is a positive integer.
Preferably, each set of performance data includes: the outlet water temperature T of the cooling towernThe water supply temperature T of the cooling towerFor supplying toThe outdoor wet bulb temperature TOuter coverThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the rated power P of the cooling water pumpForehead 1And the rated power P of the fan of the cooling towerForehead 2。
Preferably, the total heat sink power P is determinednThe method comprises the following steps: according to the outlet water temperature T of the cooling towernThe water supply temperature T of the cooling towerFor supplying toDetermining the power P of the water chilling unit according to the load Q of the water chilling unitCold n(ii) a According to the power P of the water chilling unitCold nThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the outdoor wet bulb temperature TOuter coverRated power P of the cooling water pumpForehead 1Rated power P of fan of cooling towerForehead 2Determining the Power P of the Cooling Water Pumpn1And fan power P of cooling towern2(ii) a According to the power P of the cooling water pumpn1Fan power P of the cooling towern2And the power P of the water chilling unitCold nDetermining the total cold source power P of the cooling water systemn。
Preferably, the cold is determinedPower P of water pumpn1And the fan power P of the cooling towern2The method comprises the following steps: according to the power P of the water chilling unitCold nDetermining the frequency F of the cooling water pump according to the load Q of the water chilling unit and the set temperature difference △ T of the cooling water pumpn1(ii) a According to the power P of the water chilling unitColdn, load Q of the water chilling unit and the outdoor wet bulb temperature TOuter coverDetermining a fan frequency F of the cooling towern2(ii) a According to the frequency F of the cooling water pumpn1And the rated power P of the cooling water pumpForehead 1Determining the power P of the cooling water pumpn1(ii) a According to the fan frequency F of the cooling towern2And the rated power P of the fan of the cooling towerForehead 2Determining a fan power P of the cooling towern2。
Preferably, the n determined total cooling source powers P are usednThe controlling the operation of the cooling water system with the performance data corresponding to the minimum value of (a) includes: controlling fans of the cooling tower to match the determined n total cold source powers PnAnd controlling the cooling water pump to operate at the fan frequency of the cooling tower corresponding to the minimum value of the n total cold source powers PnThe minimum value of (3) corresponds to the frequency operation of the cooling water pump.
The invention also provides a control device of a cooling water system of a central air conditioner, the central air conditioner comprises a cooling tower, a cooling water pump and a water chilling unit, and the device comprises: the system comprises a processing unit and a control unit, wherein the processing unit is used for establishing a curve database according to performance parameters of equipment of the cooling water system, wherein the curve comprises curves related to the power of the water chilling unit, the power of the cooling water pump and the power of a fan of the cooling tower; determining the total cold source power P according to each of the n sets of performance data and the curve of the curve databasen(ii) a The control unit is used for determining n total cold source powers PnThe performance data corresponding to the minimum value in (1) controls the operation of the cooling water system, wherein n is a positive integer.
Preferably, each set of performance data includes: water outlet of the cooling towerTemperature TnThe water supply temperature T of the cooling towerFor supplying toThe outdoor wet bulb temperature TOuter coverThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the rated power P of the cooling water pumpForehead 1And the rated power P of the fan of the cooling towerForehead 2。
Preferably, the control unit is further configured to: according to the outlet water temperature T of the cooling towernThe water supply temperature T of the cooling towerFor supplying toDetermining the power P of the water chilling unit according to the load Q of the water chilling unitCold n(ii) a According to the power P of the water chilling unitCold nThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the outdoor wet bulb temperature TOuter coverRated power P of the cooling water pumpForehead 1Rated power P of fan of cooling towerForehead 2Determining the Power P of the Cooling Water Pumpn1And fan power P of cooling towern2(ii) a According to the power P of the cooling water pumpn1Fan power P of the cooling towern2And the power P of the water chilling unitCold nDetermining the total cold source power P of the cooling water systemn。
Preferably, the control unit is further configured to: according to the power P of the water chilling unitCold nDetermining the frequency F of the cooling water pump according to the load Q of the water chilling unit and the set temperature difference △ T of the cooling water pumpn1(ii) a According to the power P of the water chilling unitCold nThe load Q of the water chilling unit and the outdoor wet bulb temperature TOuter coverDetermining a fan frequency F of the cooling towern2(ii) a According to the frequency F of the cooling water pumpn1And the rated power P of the cooling water pumpForehead 1Determining the power P of the cooling water pumpn1(ii) a According to the fan frequency F of the cooling towern2And the rated power P of the fan of the cooling towerForehead 2Determining a fan power P of the cooling towern2。
Preferably, the control unit is further configured to: controlling fans of the cooling tower to match the determined n total cold source powers PnThe fan frequency of the cooling tower corresponding to the minimum value of (3) is operated,and controlling the cooling water pump to control the n total heat sink powers PnThe minimum value of (3) corresponds to the frequency operation of the cooling water pump.
The embodiment of the invention also provides a central air conditioner which comprises the control device of the cooling water system of the central air conditioner.
By adopting the technical scheme, the method and the device for controlling the cooling water system of the central air conditioner and the central air conditioner provided by the invention comprise the following steps: establishing a curve database according to performance parameters of equipment of the cooling water system, wherein the curve comprises curves related to the power of the water chilling unit, the power of the cooling water pump and the power of a fan of the cooling tower; determining the total cold source power P according to each of the n sets of performance data and the curve of the curve databasen(ii) a With the determined n total cold source powers PnThe performance data corresponding to the minimum value in (1) controls the operation of the cooling water system, wherein n is a positive integer. The optimal state of the cooling water is found to correspond to the optimal cooling tower outlet water temperature by calculating the energy consumption of the outlet water temperature of each cooling tower, and the frequency of a fan and a cooling water pump of the cooling tower is regulated and controlled to enable the cooling water system to reach the state of minimum total energy consumption.
Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration and explanation only, not limitation.
Fig. 1 is a flowchart of a method for controlling a cooling water system of a central air conditioner according to an embodiment of the present invention. As shown in fig. 1, the central air conditioner includes a cooling tower, a cooling water pump and a water chiller, and the method includes: establishing a curve database according to performance parameters of equipment of the cooling water system, wherein the curve comprises curves related to the power of the water chilling unit, the power of the cooling water pump and the power of a fan of the cooling tower (step S11); determining the total cold source power P according to each of the n sets of performance data and the curve of the curve databasen(step S12); with the determined n total cold source powers PnThe performance data corresponding to the minimum value of (a) controls the operation of the cooling water system (step S13), wherein n is a positive integer.
In this embodiment, the performance parameters of the device may include: water outlet temperature T of cooling towernWater supply temperature T of cooling towerFor supplying toOutdoor wet bulb temperature TOuter coverLoad Q of water chilling unit, set temperature difference △ T of cooling water pump and rated power P of cooling water pumpForehead 1And rated power P of fan of cooling towerForehead 2Frequency F of cooling water pumpn1Fan frequency F of cooling towern2And the like.
According to the performance parameters, collecting and learning are carried out for a period of time to form a water chilling unitPower P ofCold nPower P of cooling water pumpn1And fan power P of the cooling towern2Etc., wherein the curves may have at least the following functional relationship:
Pcold n=f1((Tn-TFor supplying to) Q), power P of the chillerCold nAnd the outlet water temperature T of the cooling tower entering the condensernAnd the supply water temperature T of the chilled water exiting the evaporatorFor supplying toThe difference in (c) is related to the load Q of the chiller, preferably a quadratic curve relationship.
Pn2=PForehead 2f2(Fn2) Fan power P of cooling towern2And rated power P of fan of cooling towerForehead 2And fan frequency F of the cooling towern2In this connection, a cubic curve relationship is preferred.
Pn1=PForehead 1f3(Fn1) Power P of cooling water pumpn1And rated power P of cooling water pumpForehead 1And frequency F of the cooling water pumpn1In this connection, a cubic curve relationship is preferred.
Tn=f4(Fn2,Fn1,TOuter cover) Outlet water temperature T of cooling towernThe frequency F of the cooling water pump is related to the air quantity change brought by a fan of the cooling tower, the water quantity change brought by a cooling water pump and the heat exchange temperature brought by the outdoor wet bulb temperaturen1And outdoor wet bulb temperature TOuter coverA linear relationship may be a first order relationship in all cases.
In addition, according to the heat release balance, the cooling water pump adopts temperature difference control, has fixed set temperature difference, and can calculate the frequency F of the cooling water pumpn1. The heat release is the same in the cooling water transfer process and the cooling tower heat dissipation process, so that the fan frequency F of the cooling tower can be obtainedn2。
QExothermic heat generation=PCold n+Q=ΔTf5(Fn1);
QExothermic heat generation=PCold n+Q=f6(Fn2,TOuter cover)。
In this embodiment, using the above curve relationship, n total cold source powers P can be obtained according to the following performance datanPower per total heat sink PnObtained from a set of performance data, each set of performance data comprising:
water outlet temperature T of cooling towernThe water supply temperature T of the cooling towerFor supplying toThe outdoor wet bulb temperature TOuter coverThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the rated power P of the cooling water pumpForehead 1And the rated power P of the fan of the cooling towerForehead 2The performance data can be obtained by detection, query and the like.
Finding n total cold source powers PnAnd using total heat sink power PnThe performance data corresponding to the minimum value of (a) controls the operation of the cooling water system. When the working condition changes to a certain degree, the total cold source power P needs to be determined againnMinimum value of (1).
Wherein, in the embodiment of the invention, the outlet water temperature T of the n cooling towers can be setnWherein the initial value (i.e., first time plotted) may be the lower limit of the cooling tower outlet water temperature (outdoor wet bulb temperature T)Outer coverThe sum of the approximate temperature differences) and the temperature T of the outlet water brought into the cooling towernThe following relationships are referenced:
Tn+1=Tn+ A, namely adding a fixed value to the outlet water temperature of the cooling tower every time;
under the above condition, the total cold source power P is judgednMay be as follows: the temperature T of the outlet water continuously brought into the cooling towernIn the first discovery of Pn+1>PnWhen it is, then it is considered as PnI.e. the minimum value.
Fig. 2 is a flowchart of a method for determining a total cooling source power of a cooling water system of a central air conditioner according to an embodiment of the present invention. As shown in fig. 2, the method includes: according to the outlet water temperature T of the cooling towernThe water supply temperature T of the cooling towerFor supplying toDetermining the power P of the water chilling unit according to the load Q of the water chilling unitCold n(step S21); according to the power P of the water chilling unitCold nThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the outdoor wet bulb temperature TOuter coverRated power P of the cooling water pumpForehead 1Rated power P of fan of cooling towerForehead 2Determining the Power P of the Cooling Water Pumpn1And fan power P of cooling towern2(step S22); according to the power P of the cooling water pumpn1Fan power P of the cooling towern2And the power P of the water chilling unitCold nDetermining the total cold source power P of the cooling water systemn(step S23).
In the present embodiment, by using the performance data: water outlet temperature T of cooling towernWater supply temperature T of cooling towerFor supplying toAnd the load Q of the water chilling unit, and using the functional relation P of the curveCold n=f1((Tn-TFor supplying to) Q), the power P of the chiller can be determinedCold nAnd at a determined power P of the water chilling unitCold nOn the basis of the obtained power P of the cooling water pumpn1And fan power P of cooling towern2Adding the power P of the chillerCold nPower P of cooling water pumpn1And fan power P of cooling towern2The total cold source power P can be obtainedn。
Fig. 3 is a flowchart of a method for determining power of a cooling water pump and power of a fan of a cooling tower of a central air-conditioning cooling water system according to an embodiment of the present invention. As shown in fig. 3, the method includes: according to the power P of the water chilling unitCold nDetermining the frequency F of the cooling water pump according to the load Q of the water chilling unit and the set temperature difference △ T of the cooling water pumpn1(step S31); according to the power P of the water chilling unitCold nThe load Q of the water chilling unit and the outdoor wet bulb temperature TOuter coverDetermining a fan frequency F of the cooling towern2(step S32); according to the frequency F of the cooling water pumpn1And the rated power P of the cooling water pumpForehead 1Determining the power P of the cooling water pumpn1(step S33); according to the fan frequency of the cooling towerRate Fn2And the rated power P of the fan of the cooling towerForehead 2Determining a fan power P of the cooling towern2(step S34).
In the present embodiment, the power P of the cooling water pump is providedn1And fan power P of cooling towern2The manner of obtaining (a).
By using the power P of the chillerCold nLoad Q of the water chilling unit and set temperature difference △ T of the cooling water pump, and utilizes the function relation Q of the curveExothermic heat generation=PCold n+Q=ΔTf5(Fn1) The frequency F of the cooling water pump can be determinedn1;
By using the power P of the chillerCold nLoad Q and outdoor wet bulb temperature T of water chilling unitOuter coverAnd using the functional relationship Q of the curves described aboveExothermic heat generation=PCold n+Q=f6(Fn2,TOuter cover) The fan frequency F of the cooling tower can be determinedn2;
Frequency F by using cooling water pumpn1And rated power P of cooling water pumpForehead 1Using the functional relationship P of the curves described aboven1=PForehead 1f3(Fn1) The power P of the cooling water pump can be determinedn1;
Fan frequency F by using cooling towern2And rated power P of fan of cooling towerForehead 2Using the functional relationship P of the curves described aboven2=PForehead 2f2(Fn2) The fan power P of the cooling tower can be determinedn2。
Fig. 4 is a flowchart of a method for controlling a central air-conditioning cooling water system according to another embodiment of the present invention. As shown in fig. 4, the method includes: establishing a curve database according to performance parameters of equipment of the cooling water system, wherein the curve comprises curves related to the power of the water chilling unit, the power of the cooling water pump and the power of a fan of the cooling tower (step S41); determining the total cold source power P according to each of the n sets of performance data and the curve of the curve databasen(step (I))Step S42); controlling fans of the cooling tower to match the determined n total cold source powers PnAnd controlling the cooling water pump to operate at the fan frequency of the cooling tower corresponding to the minimum value of the n total cold source powers PnWhere n is a positive integer, the frequency of the cooling water pump corresponding to the minimum value of (a) is operated (step S43).
When the state of system equipment is not changed and the internal chamber load, the chilled water supply water temperature and the outdoor wet bulb temperature are all determined for a period of time, the total cold source power PnFrequency F of cooling water pumpn1And fan frequency F of the cooling towern2It is related. Therefore, in this embodiment, when the total heat sink power P is determinednAfter the minimum value, the frequency of the cooling water pump and the frequency of the fan of the cooling tower corresponding to the minimum value can be obtained from the process of determining the minimum value, the fan of the cooling tower is controlled to operate at the frequency of the fan of the cooling tower, and the cooling water pump is controlled to operate at the frequency of the cooling water pump, so that the cooling water system reaches a state of minimum total energy consumption. For example, if the total heat sink power PnIs P5Then control the cooling water pump to F51Operating, controlling fans of the cooling tower at F52And (5) operating.
Fig. 5 is a flowchart of a control device of a central air-conditioning cooling water system according to another embodiment of the present invention. As shown in fig. 5, the present invention also provides a control device for a cooling water system of a central air conditioner, the central air conditioner comprises a cooling tower, a cooling water pump and a water chilling unit, the device comprises: the system comprises a processing unit 1 and a control unit 2, wherein the processing unit 1 is used for establishing a curve database according to performance parameters of equipment of the cooling water system, wherein the curve comprises curves related to the power of the water chilling unit, the power of the cooling water pump and the fan power of the cooling tower; determining the total cold source power P according to each of the n sets of performance data and the curve of the curve databasen(ii) a The control unit 2 is used for determining n total cold source powers PnThe performance data corresponding to the minimum value in (1) controls the operation of the cooling water system, wherein n is a positive integer.
Preferably, each set of performance data includes: the outlet water temperature T of the cooling towernThe water supply temperature T of the cooling towerFor supplying toThe outdoor wet bulb temperature TOuter coverThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the rated power P of the cooling water pumpForehead 1And the rated power P of the fan of the cooling towerForehead 2。
Preferably, the control unit 2 is further configured to: according to the outlet water temperature T of the cooling towernThe water supply temperature T of the cooling towerFor supplying toDetermining the power P of the water chilling unit according to the load Q of the water chilling unitCold n(ii) a According to the power P of the water chilling unitCold nThe load Q of the water chilling unit, the set temperature difference △ T of the cooling water pump and the outdoor wet bulb temperature TOuter coverRated power P of the cooling water pumpForehead 1Rated power P of fan of cooling towerForehead 2Determining the Power P of the Cooling Water Pumpn1And fan power P of cooling towern2(ii) a According to the power P of the cooling water pumpn1Fan power P of the cooling towern2And the power P of the water chilling unitCold nDetermining the total cold source power P of the cooling water systemn。
Preferably, the control unit 2 is further configured to: according to the power P of the water chilling unitCold nDetermining the frequency F of the cooling water pump according to the load Q of the water chilling unit and the set temperature difference △ T of the cooling water pumpn1(ii) a According to the power P of the water chilling unitCold nThe load Q of the water chilling unit and the outdoor wet bulb temperature TOuter coverDetermining a fan frequency F of the cooling towern2(ii) a According to the frequency F of the cooling water pumpn1And the rated power P of the cooling water pumpForehead 1Determining the power P of the cooling water pumpn1(ii) a According to the fan frequency F of the cooling towern2And the rated power P of the fan of the cooling towerForehead 2Determining a fan power P of the cooling towern2。
Preferably, the control unit 2 is further configured to: controlling a fan of the cooling tower toN total determined cold source powers PnAnd controlling the cooling water pump to operate at the fan frequency of the cooling tower corresponding to the minimum value of the n total cold source powers PnThe minimum value of (3) corresponds to the frequency operation of the cooling water pump.
The embodiment of the invention also provides a central air conditioner which comprises the control device of the cooling water system of the central air conditioner.
By adopting the technical scheme, the control method and the control device for the cooling water system of the central air conditioner and the central air conditioner provided by the invention, the optimal state of the cooling water corresponding to the optimal cooling tower outlet water temperature is found by calculating the energy consumption of the outlet water temperature of each cooling tower, and the frequency of the fan and the cooling water pump of the cooling tower is regulated and controlled to enable the cooling water system to reach the state of minimum total energy consumption.
Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solutions of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications all belong to the protection scope of the embodiments of the present invention.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, the embodiments of the present invention do not describe every possible combination.
Those skilled in the art will understand that all or part of the steps in the method according to the above embodiments may be implemented by a program, which is stored in a storage medium and includes several instructions to enable a single chip, a chip, or a processor (processor) to execute all or part of the steps in the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In addition, any combination of various different implementation manners of the embodiments of the present invention is also possible, and the embodiments of the present invention should be considered as disclosed in the embodiments of the present invention as long as the combination does not depart from the spirit of the embodiments of the present invention.