CN107451397B - Cooling tower fan based on optimized operation and adjusting mode accurate quantitative optimization selection method - Google Patents

Cooling tower fan based on optimized operation and adjusting mode accurate quantitative optimization selection method Download PDF

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CN107451397B
CN107451397B CN201710547141.9A CN201710547141A CN107451397B CN 107451397 B CN107451397 B CN 107451397B CN 201710547141 A CN201710547141 A CN 201710547141A CN 107451397 B CN107451397 B CN 107451397B
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air
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仇宝云
陆霞
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Yangzhou University
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Abstract

A cooling tower fan based on optimized operation and an adjusting mode accurate quantitative optimization selection method belong to the field of industrial system energy conservation, and the ventilation quantity required by the cooling tower in each week of the whole year is calculated and determined according to the local all-year environmental working conditions; initially selecting a plurality of cooling towers with feasible semi-adjustable fans and calculating and determining the operating parameters of different blade mounting angles when the cooling towers work; aiming at a plurality of feasible fans of the primarily selected cooling tower, the annual minimum energy consumption of the fans is taken as a target, and an annual optimized operation scheme of three different adjusting modes of annual variable angle, variable frequency and variable speed of the fans is calculated and determined; considering fan angle modulation and frequency converter cost, calculating and comparing operation energy consumption and total cost of a plurality of feasible fans in different optimized operation schemes all the year round, and performing accurate quantitative optimized selection on the cooling tower fan and an adjusting mode by taking the lowest total cost as a target; the result shows that the cooling tower fan based on optimized operation and the adjusting mode accurate quantitative optimization selection method provided by the invention have obvious energy-saving effect.

Description

Cooling tower fan based on optimized operation and adjusting mode accurate quantitative optimization selection method
Technical Field
The invention belongs to the field of energy conservation of industrial systems, and relates to an optimal selection method for a half-regulation fan of a cooling tower, in particular to a cooling tower fan based on optimal operation and an accurate quantitative optimal selection method for an adjusting mode, wherein the optimal operation is performed by carrying out annual angle change, frequency change and speed change on various feasible schemes aiming at different efficiency characteristics of the fan on the premise of meeting the cooling requirement on water according to the minimum ventilation quantity required by the cooling tower in different periods all the year around, and on the basis of the aim of saving the running energy consumption, the adjustment and the total equipment cost of the fan.
Background
Due to the increasing shortage of non-renewable energy sources, the rising price of energy sources such as petroleum and coal, and the like, how to efficiently utilize the energy sources and how to save energy and reduce emission has drawn national attention, the development of energy-saving and environment-friendly industry in China proposed in the thirteen-five energy-saving and environment-friendly industry development plan has many difficulties and problems, and the difficult technology of energy system optimization and the like needs to be broken through.
The circulating cooling water system is widely applied to the industrial departments of metallurgy, electric power, steel, petrochemical industry and the like, and has high energy consumption. According to statistics, the energy consumption of a circulating cooling water system accounts for about 15% of the total social energy consumption, wherein a cooling tower fan is forced to ventilate to cool circulating water, so that a large amount of electric energy is consumed. The method comprises the following steps of designing and selecting a fan and a blade installation angle of a cooling tower according to the ventilation required by the worst environment working condition all the year around, and operating the fan under the working condition of the designed maximum ventilation all the year around. In fact, the minimum ventilation quantity required by the cooling tower to meet the requirement of cold quantity heat exchange in winter and spring and autumn transition seasons is far lower than the designed maximum ventilation quantity, the overcooling ventilation operation mode of the cooling tower fan which operates at fixed blade installation angle and fixed rotating speed all the year round causes serious energy waste, and the cooling tower fan has huge energy-saving potential.
Disclosure of Invention
The invention aims to overcome the defects that the design and the selection of a cooling tower fan are unreasonable, the cooling tower fan runs according to the maximum required ventilation volume of the design all year round to generate excessive cooling and cause serious waste of energy, and provides a cooling tower fan based on optimized operation and an accurate quantitative optimization selection method of an adjusting mode, wherein the annual angle-changing, frequency-changing and speed-changing optimized operation scheme of the cooling tower fan is calculated and determined for half-adjusting fans with different efficiency characteristics; the efficiency characteristics and the adjusting mode of the cooling tower fan are accurately and quantitatively optimized and selected by comparing the optimized operation energy consumption, the adjustment and the equipment cost of various schemes, and the annual operation maintenance and the equipment cost of the fan can be saved.
In order to achieve the above purpose, the invention provides a cooling tower fan based on optimized operation and an accurate quantitative optimization selection method of an adjusting mode, which comprises the following steps:
A. calculating total ventilation resistance P of cooling towerZAnd the total impedance S.
Taking a counter-flow cooling tower as an example, each part in the tower consists of an air inlet, an air guide device, an air flow turning part before entering a water spraying device, a water spraying filler, a water spraying device supporting beam, a water distribution device, a water collector, an air cylinder ring beam inlet and an air cylinder outlet diffusion section. Wherein the resistance of the water spraying filler
Ptl＝A·ρVm (1)
In the formula, PtlThe resistance of the water spraying filler is Pa; rho is the density of air entering the tower, kg/m3(ii) a V is the average air velocity of the section of the filler, m/s; A. m is the resistance coefficient of different fillers, and is found in Table 3 in analysis of thermal and resistance properties of plastic water-drenching fillers for cooling towers.
Total draft resistance P of cooling towerzAnd total impedance S are respectively
Figure GDA0002457456830000021
Figure GDA0002457456830000022
In the formula, PzThe total ventilation resistance of the cooling tower is m gas columns; s is the total impedance, h2/(108·m5) (ii) a G is the ventilation of the cooling tower, ten thousand meters3H; i is the number of each component in the cooling tower; n is the total number of all components in the cooling tower; xii、viThe local resistance coefficient and the section air speed m/s of each component in the cooling tower are respectively.
B. And calculating and determining the minimum ventilation quantity required by the cooling tower under different environmental conditions.
Under the condition that the heat quantity and the cooling water flow quantity of the cooled equipment need to be removed are fixed, the lower the environmental temperature is, the smaller the humidity is, the smaller the minimum ventilation quantity needed by the cooling tower of the circulating cooling water system is, and the reduction of the ventilation quantity means that the fan of the cooling tower is operated to save energy. The minimum ventilation required for the cooling tower is determined by the following method:
firstly, respectively calculating the air saturated vapor pressure P' \ and the air relative humidity
Figure GDA0002457456830000024
Apparent density rho of the wet air, air moisture content x, specific enthalpy h of the wet air and value h') of saturated air enthalpy;
secondly, performing thermodynamic calculation on the counter-flow cooling tower, and calculating the characteristic number of the filler:
Ωn'＝Bλk (4)
in the formula, omegan' is the characteristic number (dimensionless) of the working filler of the counter-flow cooling tower; B. k is an experimental constant of the water spraying filler, and is obtained by table 2 in cooling tower plastic water spraying filler thermal and resistance performance analysis; λ is the mass ratio of air (in dry air) entering the packing to water entering the packing, kg (DA)/kg.
By adopting an enthalpy difference method, the cooling number of the cooling tower is as follows:
Figure GDA0002457456830000023
in the formula, omeganThe cooling number (dimensionless) for the operating characteristics of the counter-flow cooling tower; k is the coefficient of heat removal of the evaporated water volume (K)<1.0, dimensionless); cwSpecific heat of water, kJ/(kg. DEG C.); h' is the specific enthalpy of saturated air, kJ/kg (DA); h is the specific enthalpy of humid air, kJ/kg (DA); dt is the water temperature difference between the inlet water and the outlet water of the infinitesimal filler, and is DEG C; t is t1The water temperature (DEG C) entering the tower; t is t2The temperature (. degree.C.) of the water leaving the column was determined.
The calculation of the cooling number adopts a multi-stage Simpson base decomposition method, and when the calculation precision requirement is not high and delta t is less than 15 ℃, the following simplified calculation is adopted:
Figure GDA0002457456830000031
in the formula, h1”、h2"saturated air enthalpy at the water temperature of the inlet and outlet columns, kJ/kg (DA) respectively; h ism"corresponds to water temperature of tmSaturated air enthalpy, kJ/kg (DA); h is1、h2Specific enthalpy, kJ/kg (DA), of the moist air entering and leaving the column, respectively; h ismIs the average specific enthalpy of the humid air in the column, kJ/kg (DA); delta t is the temperature difference of water entering and leaving the tower, DEG C.
For a determined cooling tower filling system, under the same air-water ratio lambda, the cooling number of the cooling tower is equal to the characteristic number of the filling, namely omegan’＝ΩnIn time, the working point of the cooling tower can be calculated to calculate the corresponding water temperature t of the inlet tower at the moment1，t1Is a function of lambda. But the problems now are: on the premise of meeting the cold quantity, the inlet water temperature t is controlled1 *And the temperature difference between the inlet water and the outlet water is solved by adopting an iterative computation point-by-point approximation method to obtain the corresponding air-water ratio lambda required at the working point of the cooling tower*。
In the circulating water system of the fixed water volume operation, the corresponding ventilation volume under different environmental conditions is obtained:
Gk＝λk·Q·ρW/(ρk·10000)(k＝1，2，3，…，z) (7)
in the formula, GkUnder the k environmental conditionVentilation volume of ten thousand meters3/h；ρkIs the air density in kg/m under the k environmental condition3；ρwIs the density of the circulating water, kg/m3；λkThe mass ratio of air (calculated by dry air) entering the filler to water entering the filler under the k environmental working condition is kg (DA)/kg; z is the number of different environment working conditions.
According to different local environmental conditions all year round, the maximum value of the minimum ventilation quantity required by the cooling tower at all moments in a week is used as the required ventilation quantity of the cooling tower in the week, and the ventilation quantity required by a certain cooling tower according to the week in a typical year is shown in figure 1; for any hour, taking the maximum value of the minimum ventilation quantity required by the cooling tower at all times of the hour as the ventilation quantity required by the cooling tower in the hour, the change rule of the ventilation quantity required in each hour of a typical day is shown in fig. 2.
C. Initially selecting a feasible fan and calculating and determining actual working point parameters of different blade installation angles when the fan works in the cooling tower: flow rate GjWind pressure PjPower NjAnd efficiency ηj。
And B, determining a cooling tower ventilation required pressure performance curve equation according to the total impedance S of the cooling tower calculated by the cooling tower structure and the filler type in the step A, substituting the maximum value of all required ventilation volumes of each week of the annual cooling tower to obtain the required air pressure in the maximum ventilation volume, initially selecting 4-6 feasible fan schemes on the premise of meeting the maximum ventilation volume and the air pressure, and calculating the actual working point parameters of different blade installation angles when each fan works in the cooling tower.
Fitting a cooling tower fan performance curve provided by an equipment manufacturer to obtain a wind pressure performance curve equation of the jth blade mounting angle of the fan, combining the equation with a required pressure performance curve equation of the cooling tower, and solving to obtain the running wind volume G of the fan at the jth blade mounting angle of the cooling tower fanjAnd wind pressure Pj(j is 1, 2, 3, …, m), and the total amount is 2m, the curve of the wind volume of the fan working in the cooling tower to the blade installation angle is obtained:
αj＝αj(G) (8)
m blades of the fan in the cooling towerAir quantity G of sheet installation anglejRespectively substituting into the power performance curve equation of the corresponding blade installation angle of the fan, and calculating to obtain m power NjCalculating the efficiency eta at the time of m blade installation angles of the air blower according to the formula (9)fj
Figure GDA0002457456830000041
In the formula etafjFor setting angle alpha of jth blade of fanjI.e. the air volume is GjEfficiency of the time; rho is air density, kg/m3(ii) a g is the acceleration of gravity, m/s2. M efficiencies η calculated by equation (9)fjAnd (3) fitting a fan air volume-efficiency curve and a blade installation angle-efficiency curve:
ηfj＝ηfGj(G) (10)
ηfj＝ηfαj(α) (11)
FIG. 3 is a plot of fan blade setting angle versus efficiency as fit.
D. And (4) calculating and determining the annual optimized operation scheme of the cooling tower in different adjusting modes of the feasible fan by primary selection.
Because the fan is selected or designed according to the most unfavorable environmental working condition of the whole year, namely the maximum ventilation quantity required in summer, the rated rotating speed and the blade installation angle are determined, and because the environmental temperature is much lower in most of the whole year compared with the hottest period in summer, the minimum ventilation quantity required by the cooling tower is greatly reduced, and a large environmental temperature difference exists in one day, as shown in figures 1 and 2. Therefore, if the cooling tower fan operates at the rated rotating speed and the designed blade installation angle all the time, the supercooling phenomenon can be generated, and the energy waste is caused.
Each fan has different fan efficiency and blade installation angle characteristics, and accurate quantitative comparison is carried out on the fans of the plurality of initially selected feasible schemes of the cooling tower, and optimized operation needs to be carried out on each scheme. The optimized operation scheme comprises the following steps: the method comprises the following steps of annual variable-angle optimized operation of a cooling tower half-adjusting fan, annual variable-frequency variable-speed optimized operation of a cooling tower half-adjusting fan, annual variable-angle variable-frequency optimized operation of a cooling tower half-adjusting fan and annual variable-angle variable-frequency optimized operation of a cooling tower half-adjusting fan.
Scheme I cooling tower half-regulation fan annual variable angle optimized operation
Because the blade of the large-scale fan is half-adjusting type, the fan needs to be shut down to manually adjust the blade mounting angle, the normal work of the cooling tower is influenced by a short time, and the cost for adjusting the blade mounting angle once is high, therefore, the blade angle change of the fan is not frequent all the year, the cost for adjusting the blade mounting angle is considered, the fan is suitable for 3 blade mounting angles all the year round through calculation and comparison, the number of the angle is continuously increased, the energy-saving effect is not obvious, the angle adjusting cost is linearly increased, and the total cost is increased on the contrary.
Efficiency of the motor under any load:
Figure GDA0002457456830000051
in the formula etaemTo the motor efficiency; etaNRated efficiency for the motor; b can be found from table 1 in "calculation of efficiency and power factor of asynchronous motor under any load".
The input power of a matched motor when the jth blade installation angle of a fan in the cooling tower runs is as follows:
Figure GDA0002457456830000052
in the formula, NejThe input power of a matched motor when the jth blade mounting angle operates is kW; rho is air density, kg/m3(ii) a g is the acceleration of gravity, m/s2；ηcThe transmission efficiency of the fan and the matched motor is improved; etaemjThe motor efficiency when the cooling tower fan operates at the jth blade setting angle is calculated.
As shown in FIG. 4, in the first scheme, considering that the minimum input power of a matched motor required by variable-angle operation of a fan which meets the ventilation quantity required by a cooling tower in different seasons and weeks all the year around is greatly changed, 3 blade installation angle operations are adopted, wherein the minimum input power is alpha1、α2And alpha3Let a1>α2>α3The wind quantity under the corresponding blade installation angle of the fan is G1、G2And G3. In week 1 to t3 smallWeek and t3 is largeFrom the week to the Tth week, the fan is installed at a blade installation angle alpha3Air volume G required by cooling tower in operation and actual environment working conditionrWind quantity G less than or equal to fan operation3Running wind pressure P3Efficiency η of fanf3Efficiency η of the motorem3(ii) a At the t th3 small+1 week to t2 smallWeek and t2 is largeWeek to t3 is large1 week, fan blade setting angle α2Operate to satisfy G3<Gr≤G2Air volume G of running2Running wind pressure P2Efficiency η of fanf2Efficiency η of the motorem2(ii) a T th2 small+1 week to t2 is large1 week, fan blade setting angle α1Operate to satisfy G2<Gr≤G1Air volume G of running1Running wind pressure P1Efficiency η of fanf1Efficiency η of the motorem1. Total annual energy consumption of
Figure GDA0002457456830000053
In the formula, AzThe power consumption for the annual operation of the cooling tower fan is kW.h; t is the number of operating weeks in the whole year, and the continuous operation is counted by 52 weeks in one year.
Performing optimization calculation by software programming, taking the maximum value of the minimum ventilation quantity required by the cooling tower at all times every week as the ventilation quantity required by the cooling tower in the week for any week in the whole year, and determining the maximum blade mounting angle alpha in the 3 blade mounting angles of the fan according to the maximum value of the ventilation quantity required by the cooling tower in the whole year when the rated rotating speed and the air quantity of the fan meet the requirement of the cooling tower in the whole year1(ii) a Setting a minimum blade installation angle alpha of 3 blade installation angles of the fan according to the condition that the rated rotating speed and the air quantity of the fan just meet the minimum value of the air quantity required by the cooling tower every week all the year around3Initial value of (a)3The air quantity corresponding to the initial value is the required air with the minimum annual air quantityAmount, at blade setting angle α1And alpha3Is selected from2，α2The blade installation angle corresponding to the second largest ventilation quantity required in the last year is used as an initial value, and alpha is iteratively selected in 0.1 degree step length2Stepwise increase, for each of the above steps, according to iteratively selected alpha1、α2And alpha3For the region boundary point, substituting the fan operation parameters into formula (14) to calculate the annual power consumption of the fan, and gradually increasing the blade installation angle alpha by 0.1 degree step length3Checking the blade setting angle alpha at this time3The fan can satisfy the number of the ventilation volume, if the blade mounting angle alpha3After the step length of 0.1 degree is increased, the condition that the ventilation quantity required by the cooling tower is increased for one circle still can not be met, and the blade installation angle alpha is not carried out2And (3) iterative calculation, namely, finally determining the installation angles of the 3 kinds of blades and the operation time of each installation angle of the blades in the optimal scheme by taking the lowest annual energy consumption of the fan unit as a target.
Annual variable-frequency variable-speed optimized operation of half-adjusting fan of scheme two cooling tower
In one year, because the change of the required ventilation volume of the cooling tower per week per hour is large, as shown in fig. 1 and fig. 2, under the condition that the angle of the fan is not changed all the year round, the fan of the cooling tower adopts the variable-frequency variable-speed operation, except the initial investment of frequency converter equipment, the realization of the variable-frequency variable-speed is easy, the cost is not increased, and therefore the variable-frequency variable-speed operation per hour is adopted.
The frequency conversion speed change of the fan is carried out every hour every day, although the energy consumption of the fan is reduced after the speed change, the energy consumption of the frequency converter is increased after the frequency conversion, so that the input power of the frequency converter before and after the frequency conversion needs to be compared, if the input power of the frequency converter is increased after the frequency conversion speed change, the reduced power of the fan is not enough to compensate the increased power of the frequency converter, the frequency conversion speed change operation is not required in the hour, and the condition occurs when the speed change ratio is close to 1.0.
Scheme two is shown in figure 5, according to the maximum value G of the minimum air quantity required by the fan of the cooling tower all the year roundmaxDetermining the blade installation angle alpha of the annual operation of the fan1Rated speed fan efficiency ηf1Requiring rated rotational speed and wind volume G1Satisfies G1≥GmaxAnd implementing hourly variable frequency and variable speed operation according to the required ventilation quantity under the blade installation angle. After frequency conversion and speed change, the working condition of the fan is similar to the working condition of the rated rotating speed, the efficiency of the fan is equal, and the air quantity of the fan is equal to the ventilation quantity required by the cooling tower in each hour.
The frequency converter has the input power of the cooling tower fan with the variable-frequency and variable-speed operation
Figure GDA0002457456830000061
In the formula, NbjInputting power, kW, for the j working condition frequency converter; etabpjAnd the frequency converter efficiency of the j working condition is shown.
Frequency converter efficiency of each hour per week
Figure GDA0002457456830000062
In the formula etabpthIs at the thThe efficiency of a frequency converter for hourly fan operation; gthIs at the thTen thousand meters of operating air quantity of hourly fan3And/h, which is equal to the hourly cooling tower required draft.
The total energy consumption of the annual fan operation is
Figure GDA0002457456830000071
In the formula, AtwIs the t th fan of the cooling towerwThe power consumption is realized in one-week operation, kW.h; rhothIs at the thHourly air Density, kg/m3；PthIs at the thThe wind pressure and the m air columns are generated when the fan operates for hours; etaemthIs at the thThe fan under the hour working condition operates the matched motor efficiency; etabpthIs at the thHourly duty converter efficiency.
The method comprises the steps of performing optimization calculation by utilizing software programming, determining an initial value of a fan blade installation angle according to the maximum value of the minimum air quantity required by a fan of a cooling tower all the year round when the rated rotating speed air quantity of the fan meets the requirement of the minimum air quantity required by the fan of the cooling tower all the year round, performing hourly variable-frequency variable-speed operation according to the required air quantity under the fan blade installation angle, enabling the fan air quantity after variable-frequency variable-speed operation to be equal to the required air quantity of the cooling tower all the hour round, substituting a formula (17) to calculate the total annual energy consumption, gradually increasing the fan blade installation angle by 0.1 degree step length, circularly calculating the total annual energy consumption according to the mode, and finally determining the optimal.
As shown in fig. 3, when the maximum value G of the minimum air quantity required by the fan of the cooling tower all year round is reachedmaxAnd G is taken at the descending section of the fan blade installation angle-efficiency curve1＝GmaxAdjusting the blade installation angle to the air volume GmaxThe fan efficiency of the working condition point is the highest efficiency which can meet the annual ventilation quantity of the cooling tower at the corresponding angle; when the maximum value G of the minimum air quantity required by the fan of the cooling tower all the year roundmaxAt the ascending section of the fan blade installation angle-efficiency curve, G1Get GmaxThe point near the large air volume side having the maximum efficiency value, i.e., G1>GmaxSetting the operating point as point a in fig. 6, the uppermost descending curve is the curve of wind volume to wind pressure performance at rated speed of the fan, the lower two descending curves are the curves of wind volume to wind pressure performance after speed reduction, and the ascending curve in fig. 6 is not only the curve of wind pressure required by the cooling tower, but also the parabola of similar operating condition that the fan passes through operating point a, and the installation angle of the fan blade is adjusted to point a, and the wind volume is G1，GmaxThe small air volume side of the point A on the parabola under the similar working condition is positioned, the variable frequency speed reduction is adopted, the working condition point of the fan moves to the lower left side of the small air volume along the parabola under the similar working condition, the air volume of the new working condition point of the fan is equal to the air volume required by the cooling tower for the hour, the new working condition is similar to the original working condition A, the fan efficiency is kept unchanged, on the premise of meeting the air volume required by the cooling tower, the air volume of the fan is reduced, the operation efficiency is improved, the operation power is reduced, and the purpose of saving energy is achieved.
The fan operates at a reduced speed, the speed ratio is generally limited to be 0.6-1, the efficiency of a similar working condition point after the reduced speed is considered to be equal to that before the reduced speed, and the efficiency is set as A in the graph of fig. 61A point transmission ratio ofA1Air quantity G is 0.6 ═ GA1The shaft power of the fan is NA1Efficiency of fan is etafA1，ηfA1＝ηfA＝ηfmax(ii) a If the cooling tower needs to be ventilated with the ventilation quantity GA2，GA2<GA1The variable frequency and the variable speed of the fan are A2Point operation due to gear ratioA2<0.6, practical ηfA2<ηfA1But etafA2Comparison etafA1The decrease is small, due to A2The point air volume is obviously less than A1The point air quantity and the axial power of the fan similar working condition point are in direct proportion to the third power of the air quantity, so A2Axial power N of a pointA2Is significantly less than A1Axial power N of a pointA1Furthermore, with A1Point by point comparison, A2Point motor efficiency etaemA2Transmission efficiency etacA2And frequency converter efficiency etabpA2The variation is small, and the input power N of the frequency converter at the point A2 is known from the formula (15)bA2Is significantly less than A1Input power N of point frequency converterbA1The rotating speed of the fan is adjusted to be A by frequency conversion2The point is operated.
Annual variable-angle variable-frequency optimized operation of half-adjusting fans of three cooling towers in scheme
Because most of fan blades adopted by the cooling tower are semi-adjustable, the blades are not suitable for frequent angle adjustment and can be adjusted only for a plurality of times in one year; the cooling tower fan adopts variable-frequency variable-speed operation, so that the initial investment of frequency converter equipment is needed, the frequency conversion is very convenient, the multiple and automatic variable-frequency adjustment is easy to realize, the cost is not increased, the variable-frequency variable-speed adjustment per hour is adopted, namely, different fan blade installation angles are selected for the cooling tower at different periods in one year, namely, the rated rotating speed air quantity of the fan at the period is equal to the maximum value of the minimum air quantity required by the cooling tower at the period, different rotating speeds are selected at different time intervals in a day, so that the air volume of the fan in the hour is equal to the air volume required by the cooling tower in the hour, the power of the fan in the hour is minimum, the annual total energy consumption is minimum, an annual variable angle scheme of the fan based on hourly frequency conversion and speed change is determined, the annual variable angle scheme comprises annual variable angle times, variable angle angles and variable angle time points, the frequency conversion and variable angle optimized operation of the fan of the cooling tower is achieved, and the purpose of reducing the energy consumption of the fan is achieved.
The fan implements frequency conversion and speed change optimized operation, and only reduces the speed and does not increase the speed in consideration of safety. FIG. 7 is a relationship between the air volume and efficiency of a typical cooling tower fan and the blade installation angle, in the case of constant speed, the actual operation operating point of the cooling tower fan, one blade installation angle corresponding to one air volume and one fan efficiency, 4 peak values of the curve are respectively marked as A, B, C, D, the curve is divided into 5 sections by taking the 4 peak values as boundaries, in the first section of the curve from the left, the fan efficiency is higher and higher to the highest efficiency point A along with the increase of the blade installation angle, and on the premise that the minimum air volume required by the cooling tower is met, the fan is operated at the larger blade installation angle point A as much as possible to make the fan efficiency reach the highest, the air volume is reduced to the required air volume of the cooling tower at that hour by frequency conversion and speed reduction, the operation condition is kept similar to the highest efficiency point, and the operation efficiency is the highest; the second section of curve AB is characterized in that along with the increase of the blade installation angle, the fan efficiency is rapidly reduced and then increased to a second peak value B, a passing point B is taken as a horizontal line and is crossed with the second section of curve at a point B ', and in the range of the section AB' of the curve, because the curve is a monotone decreasing curve, along with the increase of the blade installation angle, the fan efficiency is reduced, so that on the premise of meeting the minimum air quantity required by the cooling tower, the fan blade installation angle is as small as possible, namely, the blade installation angle corresponding to the minimum air quantity required by the cooling tower is taken, so that the air quantity of the fan is ensured to be small, the efficiency is; in a curve BB 'section, the fan efficiency of a point B, B' is highest, on the premise of meeting the minimum air quantity required by the cooling tower, the fan blade installation angle of the point B is selected, and then the air quantity is reduced to the minimum air quantity required by the cooling tower through frequency conversion and speed reduction; the right curves of points BC, CD and D of the third to fifth sections of curves have the same variation trend as the section AB', and the fan efficiency decreases with the increase of the blade installation angle, so that on the premise of satisfying the minimum air volume required by the cooling tower, the fan blade installation angle should be as small as possible, that is, the blade installation angle corresponding to the minimum air volume required by the cooling tower is taken.
In summary, in a certain period, if the minimum air volume required by the cooling tower is located on the left side of point a of the curve in fig. 7, the installation angle of the fan blade should be adjusted to point a; if the required minimum air quantity is located at the section B' B, adjusting the installation angle of the fan blade to the point B, and reducing the flow of the fan to the minimum air quantity required by the cooling tower through frequency conversion and speed reduction respectively; if the minimum air quantity required by the cooling tower is positioned on the right side of the AB' section or the B point of the curve of FIG. 7, the corresponding blade installation angle is directly determined on the curve according to the minimum air quantity required to implement operation without frequency conversion and speed change.
Along with the increase of the annual operation angle number, the operation energy cost of the fan is gradually reduced, but the annual angle adjustment cost is greatly increased, and the annual total cost of the fan is gradually increased, so that 1 and 2 fan blade installation angle hourly frequency conversion optimal operation schemes are selected for comparison according to a large amount of calculation comparison.
The optimal scheme of frequency conversion operation per hour under the installation angles of 1 fan blade in the whole year is shown as scheme two. And on the premise that the second scheme ensures the blade mounting angle of the annual maximum ventilation quantity, the mounting angles of the 1 types of blades are adjusted, and the hourly frequency conversion optimal operation scheme of the 2 types of blade mounting angles of the fan all the year is solved.
Scheme III is shown in figure 8, and the mounting angles of 2 blades of the fan in the whole year are respectively alpha1、α2Let a1≥α2Rated rotational speed and air quantity of G1、G2，G1≥G2Rated speed fan efficiency of etaf1、ηf2Satisfy G1≥GmaxThe whole year T week is divided into three sections: in week 1 to t2 smallWeek and t2 is largeTurning down the installation angle of the fan blade to alpha from the week to the Tth week2The air quantity is G2Can satisfy G2≥GrThe air quantity G of the fan at rated speed is required in the two time periods2Starting to operate at variable frequency and variable speed every hour; at the t th2 small+1 week to t2 is large1 week, increase the fan blade setting angle to alpha1The air quantity is G1Can satisfy G2≤Gr≤G1At a rated speed G of the fan during the period1And starting the hourly variable frequency variable speed operation. Determining the blade installation angle of the fan in operation every week, carrying out frequency-conversion and speed-change operation on the fan every hour every day, and the total energy consumption of the fan in operation all the year around is
Figure GDA0002457456830000091
Performing optimization calculation by software programming, taking the maximum value of the minimum ventilation quantity required by the cooling tower at all times every week as the ventilation quantity required by the cooling tower in the week for any week in the whole year, and setting the large-angle alpha when the 2 blade installation angles of the fan are operated according to the maximum value of the ventilation quantity required by the cooling tower in the whole year when the rated rotating speed and the air quantity of the fan meet the requirement of the cooling tower in the whole year1Is increased step by 0.1 DEG blade setting angle alpha1Setting another blade installation angle alpha of the fan according to the minimum value that the rated rotating speed and air quantity of the fan meet the air quantity required by the cooling tower every week all the year2Is increased step by 0.1 DEG blade setting angle alpha2After the mounting angles of the fan blades which operate every week all year round are determined, the operating air quantity of the fan is made to be equal to the ventilation quantity required by the cooling tower in the hour through frequency conversion every hour, the annual energy consumption is calculated by substituting the mounting angles of the blades of different dividing points of the iteratively selected areas into a formula (18), and if the mounting angle alpha of each increased blade is increased2Alpha is not satisfied when the condition of increasing the ventilation quantity required by the cooling tower for one week is satisfied2The step size is increased again by 0.1 deg.. The lowest annual energy consumption of the fan set is taken as a target to obtain the corresponding blade installation angle alpha1、α2And a variable angle time point t2 small、t2 is largeAnd obtaining the annual fan frequency-conversion angle-changing optimized operation scheme with 2 blade mounting angles.
E. And comparing the running energy consumption and the total running cost of equipment in different optimized running schemes of the cooling tower capable of being selected primarily for a plurality of fans all the year around with the optimal fans and the adjusting mode for accurate quantitative optimization selection.
The cost of the cooling tower fan in different optimized operation schemes all the year around comprises the operation energy cost, the angle modulation cost and the initial equipment cost of the frequency converter.
The large fan blade is in a semi-adjusting type, the installation angle of the blade is manually adjusted, certain cost is needed, and the cost for adjusting the installation angle of the blade is considered when the fan variable-angle variable-frequency optimized operation scheme is determined.
Cooling tower fan energy cost
Yz＝Az·y (19)
In the formula, YzThe annual energy cost of the cooling tower fan is high; and y is the unit price of the electric charge, yuan/(kW & h).
The first scheme is that the annual angle-changing optimized operation of a half-regulation fan of the cooling tower is realized, the annual angle-adjusting cost is calculated in an accumulated mode according to 3 blade installation angles of the annual operation of the fan, and the initial cost of a frequency converter is omitted, so that the annual total cost of the annual operation of the fan of the cooling tower is equal to the sum of the operating energy cost and the angle-adjusting cost of the fan.
And the second scheme is that the cooling tower half-adjusting fan operates optimally in a frequency conversion and speed change mode all the year around, the mounting angles of the fixed blades operate in a frequency conversion and speed change mode every hour all the year around, no angle modulation cost exists, and frequency converter equipment cost exists, so that the total annual cost of the cooling tower fan is equal to the sum of the operating energy cost of the fan and the initial equipment cost of the frequency converter.
And the third scheme is that the cooling tower half-adjusting fan operates in an annual angle-variable frequency-variable optimized mode, frequency-variable operation has frequency converter equipment cost, the number of optimal angle-variable numbers according to the operation scheme is 2, 2 times of angle-adjustment cost is considered, and the annual total cost of the cooling tower fan is equal to the sum of fan operation energy cost, 2 times of angle-adjustment cost and frequency converter initial equipment cost apportionment.
The original fan scheme is to select a fan to operate at rated rotation speed and designed blade installation angle all the year round. The improved scheme of the maximum ventilation blade angle is that a plurality of feasible fans are selected to operate at rated rotating speed all the year around, and the maximum ventilation blade mounting angle required all the year around by the system is selected. And D, calculating the equipment energy consumption and the total operation cost of 5 schemes including the original fan scheme, the maximum ventilation quantity blade angle improvement schemes of various feasible fans and the scheme I-scheme III in the step D, comparing the annual energy consumption and the total cost of the fans of the various initially selected feasible schemes in a list, and finally determining the fan with the lowest total cost and the operation scheme as the optimal fan and the adjusting mode.
Determining operation air quantity according to the annual operation blade installation angle of a fan, determining 3 optimal blade installation angles of a plan year to operate according to the fan efficiency characteristics that the highest rated speed efficiency of the fan is at different blade installation angles and directly influencing the input power of a fan motor according to the distribution of ventilation quantity required for 52 weeks all the year, determining 3 optimal blade installation angles of a plan year according to a formula (14), wherein under the condition that the working points at all operation periods are determined, the fan operation air quantity and the air pressure are unchanged, so that the factors influencing energy consumption are the fan efficiency, the motor efficiency and the reducer efficiency, the fan efficiency is the main factor, considering a plurality of possible fan maximum efficiency points, if the blade installation angles at the possible fan maximum efficiency points are in 3 optimal operation working points, the annual variable-angle operation saves the energy consumption, when the fan efficiency is increased by 0.1%, the fan operation air quantity is larger, the energy consumption saved in the same time is more, and therefore, when the fan maximum efficiency points move to the direction with large blade installation And when the angle is at the maximum, the annual angle-changing operation saves the highest energy consumption.
When the variable-frequency variable-speed operation of the fan is considered, the highest point of the rated rotating speed efficiency of the fan moves to the right to reach the mounting angle of the fan blade with the maximum required ventilation quantity all the year around of the cooling tower, the corresponding mounting angle of the fan blade and the air quantity of the fan are larger, the fan keeps high efficiency unchanged by utilizing a similar principle after the air quantity is regulated through variable-frequency speed reduction, and the energy consumption of the fan in all the year around operation is reduced. If the fan with the efficiency curve cannot be selected initially, the fan can be designed in a targeted manner according to the principle, so that the highest efficiency of the fan is located at a larger blade installation angle when the fan works in the cooling tower at a rated rotating speed, and the air volume is equal to the maximum required ventilation volume of the cooling tower all the year round.
The embodiment calculation shows that the cooling tower fan and the adjusting mode which are accurately and quantitatively optimized and selected or designed are calculated by the optimized operation scheme, and compared with the original fan scheme and operation mode, the annual operation energy consumption and the total cost are saved by about 75%; meanwhile, optimized operation is implemented, and the fan selected in an optimized mode is adopted, so that the total annual operation cost of the fan is saved by 17.4%. Therefore, the cooling tower fan based on optimized operation and the adjusting mode accurate quantitative optimization selection method provided by the invention have obvious energy-saving effect.
Drawings
FIG. 1 is a chart of the required ventilation of a cooling tower on a weekly basis, typically for a year.
FIG. 2 is a graph of the amount of ventilation required in a cooling tower for each hour of a typical day.
FIG. 3 is a diagram of fan efficiency versus blade mounting angle for a cooling tower fan rated speed variable angle operating point.
FIG. 4 is a diagram of air volume and blade mounting angle for a cooling tower fan rated speed year round 3 blade mounting angle optimization operation scheme.
FIG. 5 is a graph of wind rate and blade setting angle for a year-round fixed blade setting angle per day and hour variable frequency variable speed optimized operating scheme for a cooling tower fan.
FIG. 6 is a diagram for determining the optimal operation speed ratio of the cooling tower half-adjusting fan in variable frequency and variable speed.
FIG. 7 is a diagram of a method for determining an optimal operation scheme of variable-angle variable-frequency control of different blade installation angle sections of a half-adjusting fan of a cooling tower.
FIG. 8 is a graph of wind rate and blade setting angle for an hourly variable frequency and variable speed optimized operating scheme of 2 blade setting angles of a cooling tower fan throughout the year.
Fig. 9 is a graph showing the performance of the LF-42 type fan of this embodiment in terms of air volume, air pressure, air volume and power.
FIG. 10 is a graph showing the relationship between the mounting angle of the variable angle blades of the feasible fan and the air quantity in the cooling tower of the present embodiment.
Fig. 11 is a graph showing the relationship between the rated rotational speed variable-angle operating efficiency of the feasible fan and the air volume of the cooling tower in the embodiment.
FIG. 12 is a graph of efficiency at different blade setting angles at the highest efficiency point for a rated rotation speed of a fan of a cooling tower according to the present embodiment versus blade setting angle.
Detailed Description
The following uses the technical solutions of the present invention to further describe the present invention with reference to the accompanying drawings and embodiments, but the present invention should not be construed as being limited thereto.
One workshop of a chemical plant has 1 LDCM-800SC type cooling tower, local atmospheric pressure 754mmHg, density 1.13kg/m3Cooling water flow rate of 800m3/h. A fan model LF-42 is originally selected, half-regulated, matched with a three-phase asynchronous motor Y180L-4, rated power 22kW, rated current 43A, motor efficiency 90%, rotating speed 1470r/min and matched with a special frequency converter for a VFD220CP43B-21 fan water pump. The cooling tower was equipped with a model LJ3 reducer, which was 92% efficient. Price per unit of local electricity charge 06 yuan/(kW h).
The original operation scheme of the fan is as follows: the blade operates at the rated rotation speed of 200r/min and the installation angle of 13 degrees all year round, and the operation air quantity is 45.3769 ten thousand meters3The operating power is 18.4877kW, the input power of the motor is 21.88kW, the total annual operating power consumption is 191144 kW.h, and the total energy cost is 114686 yuan.
A. Calculating total ventilation resistance P of cooling towerZAnd the total impedance S.
The tower structure of the known LDCM-800SC cooling tower is as follows: packing area 46m2Air inlet area 46m2The length of the air guide device is 3 m; net ventilation area 41m for water drenching device2Water distribution device net ventilation area 43m2And the net ventilation area of the water collector is 43m226m of air duct inlet area2Throat area of wind tube is 14.12m2Area of outlet of air duct 25.53m2The water spraying filler is in an inclined trapezoidal wave shape, the taper angle of the inlet of the air duct is 120 degrees, and the taper angle of the outlet of the air duct is 60 degrees.
In the example, 1.0m of oblique gradient wave water spraying filler is selected, and a is 9.2449 and m is 2.05538 which can be found in table 3 of analysis on thermal and resistance properties of plastic water spraying filler of a cooling tower; the resistance of the water spraying filler is calculated by the formula (1)
Ptl＝A·ρVm＝9.2449×1.13×2.862.05538＝90.57Pa
According to the cross-sectional area and the resistance coefficient of each component in the cooling tower, the total ventilation resistance of the cooling tower can be obtained by the formula (2):
Figure GDA0002457456830000121
total resistance P of cooling towerzThe total impedance of formula (3) is substituted
Figure GDA0002457456830000122
B. And calculating and determining the minimum ventilation quantity required by the cooling tower under different environmental conditions.
Taking an environmental condition as an example, the following is calculated:
environmental conditions are as follows: atmospheric pressure 100.56kPa, dry-bulb temperature: 27 ℃, wet bulb temperature: at 25 ℃, according to the cooling requirement of the equipment, the maximum temperature of water entering the tower is controlled to be 45 ℃, and the temperature difference between water entering the tower and water leaving the tower is 10 ℃. The saturated water vapor partial pressures at 27 ℃ and 25 ℃ are respectively Pd”＝3.5631kPa、Ps"═ 3.1655kPa, air relative humidity was
Figure GDA0002457456830000123
The apparent density of the wet air is rho 1.1569kg/m3The air moisture content x is 0.0193kg/kg (da).
When the gas-water ratio is the same, omegan’＝ΩnAnd is the working point of the cooling tower. In order to obtain the water temperature t of the cooling tower entering the tower1Water temperature t out of the tower is 45 DEG C2And (4) carrying out trial calculation on the corresponding gas-water ratio lambda at the equilibrium working point at 35 ℃.
Making the initial value of gas-water ratio lambda be 0.49kg (DA)/kg, selecting 1.0m oblique gradient wave water-spraying filler, obtaining B, k coefficient by table 2 in "analysis of thermal and resistance properties of plastic water-spraying filler of cooling tower", substituting formula (4) to obtain characteristic number of filler
Ωn'＝Bλk＝1.60×0.40.64＝0.89
The enthalpy of the wet air entering the tower is calculated to be h176.362kJ/kg (DA), the coefficient of heat taken away by the evaporated water K is 0.9394, and the enthalpy h of the wet air discharged from the tower2187.7842kJ/kg (DA), average enthalpy h of wet air in the columnm＝132.0731kJ/kg(DA)，t1、t2、tmCorresponding partial pressures of saturated water vapor of Pt1”＝9.5803kPa、Pt2”＝5.6207kPa、Ptm"═ 7.3737kPa, the corresponding saturated air specific enthalpies are h respectively1”＝214.4617kJ/kg(DA)、h2”＝129.6436kJ/kg(DA)、hm”＝166.9191kJ/kg(DA)。
Obtaining the cooling number of the cooling tower of formula (6)
Figure GDA0002457456830000131
Comparing the characteristic number of the filler with the cooling number of the cooling tower, omega is foundn’＝0.89<ΩnWhen the gas-water ratio is increased to 1.2705, the calculation is repeated until | Ω |n-Ωn’|<0.001, obtaining the corresponding coordinates of the balance working point as (0.4737, 45), and substituting equation (7) to obtain the ventilation quantity of the calculated working condition:
Figure GDA0002457456830000132
according to the method, the minimum ventilation quantity required by the cooling tower under different environmental working conditions at all times all the year is calculated, and the maximum ventilation quantity G all the year is obtainedmax41.2454 ten thousand meters3/h。
C. Initially selecting a feasible fan and calculating and determining actual working point parameters of different blade installation angles when the fan works in the cooling tower: flow rate GjWind pressure PjPower NjAnd efficiency ηj。
Under the premise of meeting the maximum air quantity and the maximum air pressure, by taking an initially selected LF-42 type feasible fan as an example, fig. 9 is an air quantity and air pressure, air quantity and power performance curve of the LF-42 type fan adopted by the cooling tower in the embodiment of the invention, and an air quantity-air pressure performance curve equation of a 13-degree blade installation angle is obtained by fitting
P13＝-0.000069G3+0.0057G2-0.4205G+24.4712
The curve equation of the air quantity-power performance of the 13-degree blade installation angle is obtained by fitting
N13＝0.0005G3-0.0723G2+3.1266G-24.1831
The cooling tower needs a pressure performance curve equation: P-0.00514G2
The flow G of the actual operation working point of the 13-degree blade mounting angle obtained by solving the simultaneous equation is 45.3769 ten thousand meters3And h, wind pressure P is 10.6742m, and power N is 18.4877 kW.
The performance curves of the installation angles of other blades of the fan are fitted by the method, one curve is fitted at intervals of 0.1 degrees from 2 degrees to 22 degrees, 201 wind volume-wind pressure performance curve equations are totally combined to respectively obtain the required pressure performance curve equations, 201 working point parameters are obtained by solving, and the relation curve of the installation angles of the blades to the wind volume is shown in figure 10.
The obtained wind volume G of 201 blade installation angles of the fan in the cooling towerjRespectively substituting into the power performance curve equation of the corresponding blade installation angle of the fan, and calculating to obtain 201 power NjCalculating the efficiency eta at the time of setting the 201 blades of the fan according to the formula (9)fjAs shown in fig. 11.
D. And (4) calculating and determining the annual optimized operation scheme of the cooling tower in different adjusting modes of the feasible fan by primary selection.
Different fans have different fan efficiency and blade installation angle characteristics, in the embodiment, taking an LF-42 type fan as an example, the fans respectively adopt variable angle, variable frequency and variable frequency variable angle adjustment modes to solve an optimized operation scheme, specifically as follows.
Scheme I cooling tower half-regulation fan annual variable angle optimized operation
The power of a fan shaft at a working point is 18.4877kW, a speed reducer is used for transmission, the output power of the motor is 20.0953kW, the load rate is 91.3%, b is 1.004 in a table 1 of calculation of efficiency and power factor of the asynchronous motor under any load, and the motor efficiency eta is obtained by substituting an equation (12)emIs composed of
Figure GDA0002457456830000141
Substituting each parameter value of the working point into a formula (13) to obtain the input power of a motor matched with the 13-degree blade installation angle of the fan
Figure GDA0002457456830000142
As shown in fig. 4, the fan of the scheme operates by adopting 3 blade mounting angles all the year around, the lowest annual energy cost of the fan unit is taken as a target, the three blade mounting angles of the optimal operation are determined to be 9.6 degrees, 2.0 degrees and-2.5 degrees respectively through optimization calculation, and the annual optimal operation scheme is shown in table 1.
TABLE 1 example cooling tower half-adjusting fan annual 3 kinds blade mounting angle variable optimization operation scheme
Figure GDA0002457456830000143
Substituting the annual optimal operation scheme into an equation (14), and calculating to obtain the annual variable-angle optimal operation scheme with the total operation energy consumption Az＝85988kW·h。
Annual variable-frequency variable-speed optimized operation of half-adjusting fan of scheme two cooling tower
As shown in FIG. 5, the scheme meets the maximum required ventilation G of the cooling tower all the year roundmax41.2454 km3On the premise of h, 1 determined blade installation angle alpha of the annual running of the fan is set110.1 degrees, the rated speed and the air quantity of the fan are 41.9791 ten thousand meters3And/h, the rated rotating speed efficiency is 80.73%, the frequency conversion operation is carried out on the fan every day and every hour, as shown in figure 6, the frequency conversion efficiency every hour is solved by a formula (16), and coefficients A, B, C are-0.0266, 0.0992 and 0.9054 respectively. In trial calculation, if the input power of the frequency converter is increased after frequency conversion, the frequency conversion is not carried out in the hour. The formula (17) is replaced, and the total annual fan operation energy consumption is Az＝48289kW·h。
Annual variable-angle variable-frequency optimized operation of half-adjusting fans of three cooling towers in scheme
As shown in fig. 8, the scheme adopts the frequency conversion optimized operation of 2 blade installation angles of the fan all the year around per hour, and the 2 optimal blade placement angles of the fan operation are calculated by trial to be 10.1 degrees and 6 degrees respectively by taking the minimum total energy consumption of the fan operation all the year around as a target. In the 1 st to 22 nd weeks and the 38 th to 52 th weeks, the fan operates at a blade mounting angle of 6 degrees, namely, at the point A in FIG. 7, the rated speed and the rated air quantity of the fan are 35.9505 ten thousand meters3The efficiency of the fan is 88.85 percent, the required air quantity of the cooling tower in the two time periods is met, and the fan is 35.9505 ten thousand meters3The air volume begins to operate in a variable frequency and variable speed mode; in the 23 rd week to the 37 th week, the fan operates at a blade setting angle of 10.1 degrees, namely point B in figure 7, and the rated rotating speed and the rated air quantity of the fan are41.9791 km in ten thousand3The efficiency of the fan is 80.73 percent, the required air quantity of the cooling tower in the time period is met, and the fan is 41.9791 ten thousand meters3And the air volume/h starts variable-frequency variable-speed operation. Formula (18) is substituted, and total energy consumption A of annual fan operationz＝46796kW·h。
E. And calculating and comparing the running energy consumption and the total running cost of equipment with the optimal fan and the adjusting mode according to different optimized running schemes of the cooling tower capable of being selected primarily for all the year around.
As shown in fig. 12, curves 1 to 5 are relations between efficiency and blade installation angle at rated rotation speed when 5 fans are installed in a cooling tower, and the maximum efficiency points of the 5 fans are respectively at different blade installation angles, wherein curve 4 is a relation curve between efficiency and blade installation angle of an originally selected LF-42 type fan, and the maximum efficiency point is at a blade installation angle of 6 degrees, and the energy consumption conditions of optimized operation schemes of fans with different efficiency characteristics in different adjustment modes all the year are calculated and compared.
As shown in fig. 12, 5 curves represent the relationship between the fan efficiency and the blade installation angle when the fans with different characteristics of the cooling tower operate at variable angles, the maximum efficiency of the fans is kept unchanged, the blade installation angles corresponding to the maximum fan efficiency points and the air volume of the fans with different efficiency characteristics are different, the blade installation angles corresponding to the maximum fan efficiency points of the 5 curves are respectively-6 °, 2 °, 6 °, 9.6 °, and the numbers of the curves are sequentially 1, 2, 3, 4, and 5. The cooling tower fans adopt different optimized operation modes, the annual total cost of the cooling tower fans is different, and the original operation scheme of the fans, the annual operation energy consumption, the energy cost, the angle modulation cost, the frequency converter cost and the total cost of 5 schemes, namely a fan blade installation angle scheme, a scheme I to a scheme I and a scheme II, are determined according to the annual maximum required ventilation rate of the cooling tower, wherein the unit price of the electric charge is calculated according to 0.6 yuan/(kW & h), and the cost required for one time of half-regulation fan angle modulation is 400 yuan; the initial investment cost of the special frequency converter for the VFD220CP43B-21 type fan water pump is 4500 yuan, the service life is 10 years, the residual value is 500 yuan, and the cost of the frequency converter allocated to each year is 400 yuan.
The optimized operation calculation results of each scheme of the 5 feasible fans with different efficiency characteristics are shown in tables 2-6. Taking the fan with the highest efficiency at the 6-degree blade installation angle in the table 5 as an example to compare different operation schemes, compared with the original scheme, the blade installation angle is adjusted to be 9.6 degrees of the maximum air quantity required by the cooling tower all the year around, and the energy cost is saved by 17.36 percent all the year around; in the first scheme, the fan runs optimally at the variable mounting angles of 3 blades all the year round, so that the energy is saved by 55.01 percent, and the total cost is saved by 53.62 percent; in the second scheme, the full-year fixed blade installation angle of the cooling tower half-adjusting fan is subjected to frequency-variable speed-variable optimized operation every hour every day, so that 74.74% of energy is saved, and 74.39% of total cost is saved; and in the third scheme, the frequency conversion energy-saving effect per hour is the best under 2 optimal blade installation angles all the year round, and compared with the original scheme, the frequency conversion energy-saving device saves energy by 75.53% and saves the total cost by 74.49%. When the number of the blade installation angles adopted all the year is increased to 2, the energy consumption of variable-frequency variable-angle operation is slightly reduced, but the increase of the angle modulation cost is considered, the total cost saving rate is not obvious, the increase of the total cost saving rate of the fans which can be operated in the tables 2, 4 and 5 is only 0.05 percent, 0.12 percent and 0.1 percent, the increase of the total cost saving rate of the fans which can be operated in the tables 3 is reduced by 0.2 percent on the contrary, and if the labor cost of angle modulation is increased, the total cost of the variable-angle variable-frequency optimized operation scheme of the fans which can perform angle modulation for 2 times all the year certainly exceeds the variable-frequency variable-.
TABLE 2 comparison of annual cost of optimum operation scheme of best efficiency time-varying and angle-varying for fan-6 degree blade installation angle of cooling tower
Figure GDA0002457456830000161
TABLE 3 comparison of annual cost of optimum operation plan of best efficiency time-varying and angle-varying for fan-2 degree blade installation angle of cooling tower
Figure GDA0002457456830000162
Figure GDA0002457456830000171
TABLE 4 comparison of annual costs for optimum operating schemes of 2-degree blade installation angle of cooling tower fan and variable frequency variable angle at the time of highest efficiency
Figure GDA0002457456830000172
TABLE 5 annual cost comparison of optimized operating schemes for the cooling tower of this example with the highest efficiency at 6 ° blade setting angle
Figure GDA0002457456830000173
TABLE 6 comparison of annual cost of optimum operation schemes of 9.6 degree blade installation angle of cooling tower fan and variable frequency variable angle at the time of highest efficiency
Figure GDA0002457456830000174
Figure GDA0002457456830000181
Comparing the energy consumption and the cost of various operation schemes of the fan with 5 efficiency characteristics in the embodiment, the energy consumption and the total cost change rule of the fan with 5 efficiency characteristics are consistent, compared with the original fan scheme, the energy saving rate of the scheme one is about 50%, the energy saving rate of the scheme two and the scheme three exceeds 70%, the scheme one is operated in an angle-variable optimization mode of 3 blade installation angles all the year around, the comparison is carried out from the table 2 to the table 6 of the fan, the efficiency of the working point corresponding to the 3 optimal blade installation angles determined in the scheme one is all at the peak point or the sub-peak point of the fan efficiency, the operation divides 52 weeks all the year around into three sections, the operation time of each section is basically equivalent, the comparison tables 4 to the table 6 are carried out, the installation angles of the 3 optimal operation blades are all-2.5 degrees, 2 degrees and 9.6 degrees, the operation time periods are the same, the operation air volume of the fan in each time period is unchanged, The efficiency of the speed reducer and the efficiency of the fan are main factors, when the efficiency of the fan is increased by 0.1 percent, the larger the running air quantity of the fan is, the more energy is saved in the same time, and when the highest point of the efficiency of the fan is at the maximum running air quantity under the installation angle of blades of the fan of 9.6 degrees, the lowest energy consumption of the fan is realized all the year round in the scheme, the maximum energy saving rate reaches 57.80 percent, and the total cost saving rate is 56.40 percent; the second scheme and the third scheme both adopt hourly frequency conversion operation all year round, move to a large blade installation angle along with the highest efficiency point of the fan, obviously reduce the annual energy consumption of the fan, maximally save energy by 76.56%, and greatly reduce the total cost after the angle modulation cost and the frequency converter cost are added.
As shown by the line 5 in fig. 12, when the maximum efficiency of the cooling tower fan is located at the blade installation angle of 9.6 °, the efficiency curve of the cooling tower fan increases monotonically within the range of 2 ° → 9.6 ° of the blade installation angle, and since the annual cooling tower requires air volume less than or equal to 9.6 ° of the blade installation angle, when the blade installation angle is set at 9.6 °, and then the air volume required by the cooling tower is reduced by frequency conversion, it is ensured that the fan efficiency is highest and the annual total energy consumption is minimum, as shown in table 6. Therefore, energy cost and total cost can be guaranteed to be saved only by frequency conversion operation of 9.6 degrees of blade installation angle all the year.
In summary, the feasible fans with the highest efficiency at the 9.6-degree blade installation angle in the cooling tower in table 6 are selected, and the frequency conversion optimization operation scheme with the 9.6-degree blade installation angle is adopted as the optimal fan and the adjustment mode.
The embodiment calculation shows that the cooling tower fan and the adjusting mode which are accurately and quantitatively optimally selected or designed are calculated through the optimized operation scheme, and compared with the original fan scheme and operation mode, the annual energy cost and the total cost are saved by about 75%; meanwhile, optimized operation is implemented, and the fan selected in an optimized mode is adopted, so that the total annual operation cost of the fan is saved by 17.4%. Therefore, the cooling tower fan based on optimized operation and the adjusting mode accurate quantitative optimization selection method provided by the invention have obvious energy-saving effect.

Claims (3)

1. The cooling tower fan and adjusting mode accurate quantitative optimization selection method based on optimized operation is characterized by comprising the following steps:
step A, calculating the total ventilation resistance P of the counter-flow cooling towerZAnd the total impedance S, the solving process is as follows:
the internal resistance coefficient of the counter-flow cooling tower is introduced into the water drenching from the air inlet, the air guide deviceThe device comprises a front airflow turning device, a water spraying device supporting beam, a water distribution device, a water collector, an air duct ring beam inlet, an air duct inlet reducing section and an air duct outlet diffusing section; the resistance of the water spraying filler is Ptl＝A·ρVmWherein P istlIs the resistance of the water spraying filler, Pa; rho is the density of air entering the tower, kg/m3(ii) a V is the average air flow velocity of the section of the filler, m/s; A. m is different filler resistance coefficients; the total resistance of the cooling tower is obtained by adding the resistances of all parts
Figure FDA0002615197460000011
Then the total impedance
Figure FDA0002615197460000012
In the formula, PZM gas column for total resistance of cooling tower; s is the total impedance, h2/(108·m5) (ii) a i is the local resistance number of each part in the tower; xiiThe local resistance coefficient of the ith part of the cooling tower; n is the total number of all components in the cooling tower; v. ofiThe average flow velocity of air of each section in the cooling tower is m/s; g is the acceleration of gravity, m/s2(ii) a G is the ventilation of the cooling tower, ten thousand meters3/h；
And B: the minimum ventilation quantity required by the cooling tower under different environment working conditions is calculated and determined, and the solving process is as follows:
(1) respectively calculating the air saturated water vapor pressure P' and the air relative humidity according to different environmental working conditions all year round
Figure FDA0002615197460000014
Apparent density rho of the wet air, air moisture content x, specific enthalpy h of the wet air and value h') of saturated air enthalpy;
(2) thermodynamic calculation is carried out on the cooling tower by an enthalpy difference method, and a packing characteristic number equation omega of the cooling tower is established simultaneouslyn'＝BλkAnd cooling number equation of cooling tower
Figure FDA0002615197460000013
When omega is higher thann’＝ΩnThen, solve to obtainThe gas-water ratio lambda of the cooling tower under the actual environment working condition, wherein omegan' is the characteristic number (dimensionless) of the working filler of the counter-flow cooling tower; B. k is an experimental constant of the water spraying filler; lambda is the mass ratio of dry air entering the filler to water entering the filler, kg (DA)/kg; omeganThe cooling number (dimensionless) for the operating characteristics of the counter-flow cooling tower; k is the coefficient of heat carried away by the evaporated water; cwSpecific heat of water, kJ/(kg. DEG C.); h' is the specific enthalpy of saturated air, kJ/kg (DA); h is the specific enthalpy of humid air, kJ/kg (DA); dt is the water temperature difference between the inlet water and the outlet water of the infinitesimal filler, and is DEG C; t is t1The water temperature (DEG C) entering the tower; t is t2The temperature of water leaving the tower (DEG C); adopting a linear iterative approximation method in the calculation process until the error is within an allowable range, and finally solving the water inlet temperature t of the balance point1 *And the corresponding gas-water ratio, and quickly approaching to obtain a final solution;
(3) minimum fan air volume G required by cooling tower under actual environment working conditionk＝λk·Q·ρw/(ρk10000), k ═ 1, 2, 3, …, z, where GkIs the ventilation volume under the k environmental condition of ten thousand meters3/h；λkThe mass ratio of dry air entering the filler to water entering the filler under the k environmental working condition is kg (DA)/kg; rhowIs the density of the circulating water, kg/m3；ρkIs the air density in kg/m under the k environmental condition3(ii) a z is the number of different environment working conditions;
(4) calculating ventilation quantity needed by the cooling tower in the circumference and the ventilation quantity needed by the cooling tower in the hour;
and C: initially selecting a feasible fan and calculating and determining the actual working parameter of the jth blade mounting angle of the fan in the cooling tower during working: air quantity GjWind pressure Pj(m gas column), Power Nj(kW) and efficiency ηjThe solving process is as follows:
(1) determining a pressure performance curve equation P required by ventilation of the cooling tower according to the total impedance S of the cooling tower calculated by the step A according to the structure of the cooling tower and the type of the fillerx＝Pz＝SG2Substituting the maximum value of all the ventilation quantity required by the cooling tower in each week of the year to obtain the required wind pressure when the maximum ventilation quantity is reached,under the premise of meeting the maximum ventilation quantity and the maximum air pressure, 4-6 feasible schemes of the fan are selected preliminarily;
(2) calculating actual working parameters of different blade installation angles of each fan when the fan works in the cooling tower, combining a wind pressure performance curve equation which is fitted according to a wind pressure performance curve of the jth blade installation angle given by the use specification of the fan of the cooling tower with a required pressure performance curve equation of the cooling tower, and solving to obtain the running wind volume G of the fan at the jth blade installation angle of the fan in the cooling towerjAnd wind pressure Pj(j is 1, 2, 3, …, m), and the air volume G of the m blade installation angles of the fan in the cooling tower is obtainedjRespectively substituting into a power performance curve equation which is fitted according to a power performance curve of a corresponding blade installation angle given by a fan use specification, and calculating to obtain m power Nj(ii) a According to
Figure FDA0002615197460000021
Calculating the efficiency of the fan at the mounting angles of m blades, wherein eta isfjFor setting angle alpha of jth blade of fanjI.e. the air volume is GjEfficiency of the time; the calculated fan efficiency etafjFitting into a fan air quantity-efficiency curve or function etafj＝ηfGj(G) And blade setting angle-efficiency curve or function etafj＝ηfαj(α)；
Step D: the method comprises the following steps of (1) calculating and determining annual optimized operation schemes of a plurality of initially selected feasible fans in different adjusting modes of a cooling tower, wherein the process comprises the following steps:
because the fan is selected or designed according to the maximum ventilation quantity required in summer, which is the most unfavorable environmental working condition all the year round, the rated rotating speed and the blade installation angle are determined, and because the environmental temperature is lower in most of the time all the year round compared with the hottest period in summer and the environmental temperature difference exists in one day, the minimum ventilation quantity required by the cooling tower is reduced when the environmental temperature is low, the supercooling phenomenon can be generated if the fan of the cooling tower runs according to the rated rotating speed and the designed blade installation angle all the time, the energy waste is caused, and the optimal operation of the fan needs to be implemented;
each fan has different fan efficiency and blade installation angle characteristics, accurate quantitative calculation and comparison are carried out on the fans with the number of the feasible schemes of initial selection of the cooling tower, optimized operation needs to be carried out on each scheme at first, and the optimized operation scheme comprises the following steps: the first scheme is as follows: the annual angle-variable optimized operation of the half-regulating fan of the cooling tower is characterized in that: the annual frequency conversion and speed change optimized operation of the half-regulating fan of the cooling tower is characterized in that: the cooling tower half-adjusting fan operates in an annual variable-angle variable-frequency optimized mode;
the first scheme is as follows: annual variable angle optimized operation of half-regulation fan of cooling tower
Because the blades of a large-scale fan are half-adjusting type, manual adjustment of the blade installation angle is required to be carried out by stopping the fan, the normal work of a cooling tower is influenced by a short time, and certain cost is required for adjusting the blade installation angle once, therefore, the blade angle change of the fan is not too frequent all the year around, the cost for adjusting the blade installation angle is considered, the fan is suitable for 3 blade installation angles all the year around through calculation and comparison, the number of the blade installation angles is continuously increased, the energy-saving effect is not obvious, the angle adjustment cost is linearly increased, and the total cost is increased on the contrary;
calculating the efficiency of the cooling tower fan matched motor under any load:
Figure FDA0002615197460000031
the input power of a matched motor when the jth blade installation angle of the fan runs is as follows:
Figure FDA0002615197460000032
wherein etaemFor motor efficiency, ηNFor the rated efficiency of the motor, b can be found from table 1 in "calculation of efficiency and power factor of asynchronous motor under any load", NejThe input power of a matched motor when the fan runs at the jth blade installation angle is rho is air density, g is gravity acceleration and eta iscThe transmission efficiency of the fan and the matched motor is improved; etaemjThe motor efficiency when the cooling tower fan operates at the jth blade mounting angle is obtained;
scheme one adopts 3 blade installation angle operations, respectively alpha1、α2And alpha3Let a1>α2>α3Corresponding blade of fanThe air volume under the installation angle is G respectively1、G2And G3(ii) a In week 1 to t3 smallWeek and t3 is largeFrom the week to the Tth week, the fan is installed at a blade installation angle alpha3Air volume G required by cooling tower in operation and actual environment working conditionrWind quantity G less than or equal to fan operation3Running wind pressure P3Efficiency η of fanf3Efficiency η of the motorem3T is the number of the cooling tower fan operating in one year, and the number of the cooling tower fan operating in 52 weeks in one year; at the t th3 small+1 week to t2 smallWeek and t2 is largeWeek to t3 is large1 week, fan blade setting angle α2Operate to satisfy G3<Gr≤G2Air volume G of running2Running wind pressure P2Efficiency η of fanf2Efficiency η of the motorem2(ii) a T th2 small+1 week to t2 is large1 week, fan blade setting angle α1Operate to satisfy G2<Gr≤G1Air volume G of running1Running wind pressure P1Efficiency η of fanf1Efficiency η of the motorem1(ii) a The total annual operating power consumption is
Figure FDA0002615197460000033
By utilizing software programming, the large angle alpha of the fan when 3 blade installation angles of the fan are set to operate according to the condition that the rated rotating speed and the air quantity of the fan meet the maximum value of the ventilation quantity required by the cooling tower every week all the year1Setting the small angle alpha of the fan when 3 blade installation angles are operated according to the condition that the rated rotating speed and the air quantity of the fan meet the minimum value of the air quantity required by the cooling tower every week all the year3At a determined blade setting angle alpha1And alpha3In steps of 0.1 DEG, the blade mounting angle alpha is increased step by step2Calculating annual operation energy consumption by substituting the blade installation angles of different division points of the iteratively selected regions into a formula, and gradually increasing the blade installation angle alpha by 0.1-degree step length3At each increased blade setting angle α3Not satisfying the need for increased ventilation of the cooling tower for one weekCondition, then the blade mounting angle alpha is not carried out2Is calculated by continuously increasing alpha3Calculating annual operation energy consumption, and finally determining 3 blade mounting angles of the optimal scheme and the operation time of each blade mounting angle by taking the lowest annual energy consumption of the fan unit as a target;
scheme II: annual variable-frequency variable-speed optimized operation of half-regulation fan of cooling tower
In one year, because the cooling tower needs different ventilation volume every week and hour, under the condition that the fan does not change angle all the year round, the fan of the cooling tower adopts frequency conversion and speed change operation, except the initial investment of frequency converter equipment, the realization of frequency conversion and speed change is easy, the cost is not increased, and therefore the frequency conversion and speed change operation every hour is adopted;
the fan changes speed by frequency conversion every hour every day, although the energy consumption of the fan is reduced after changing speed, because the energy consumption of the frequency converter is increased after changing frequency, the input power of the frequency converter before and after changing frequency needs to be compared, if the input power of the frequency converter is increased after changing frequency and changing speed, the reduced power of the fan is not enough to compensate the increased power of the frequency converter, the fan should not operate by changing frequency and changing speed in the hour, and the condition occurs when the speed change ratio is close to 1.0; taking a week as a time unit all year round, taking the maximum value of the minimum ventilation quantity required by the cooling tower at all times in a week as the required ventilation quantity of the week, and taking the maximum value G of the minimum ventilation quantity of the week all year round as the basismaxDetermining the blade installation angle alpha of the annual operation of the fan1Rated speed fan efficiency ηf1Requiring rated rotational speed and wind volume G1Satisfies G1≥GmaxAnd implementing hourly variable-frequency variable-speed operation according to the required ventilation quantity under the installation angle of the blade; after frequency conversion and speed change, the working condition of the fan is similar to the working condition of the rated rotating speed, the efficiency of the fan is equal, the air quantity of the fan is equal to the ventilation quantity required by each hour of the cooling tower, and the input power of the frequency converter for the frequency conversion and speed change operation of the fan of the cooling tower is
Figure FDA0002615197460000041
Wherein N isbjInputting power, kW, for the j working condition frequency converter; etabpjThe frequency converter efficiency under the j working condition; tth of weekhFrequency converter effect for hourly fan operationA rate of
Figure FDA0002615197460000042
Wherein G isthIs at the thThe operation air quantity of the hour fan is A, B, C as a constant; the total energy consumption of the annual fan operation is
Figure FDA0002615197460000043
Wherein A istwIs the t th fan of the cooling towerwPower consumption in Monday operation, rhothIs at the thHourly air density, PthIs at the thHourly fan operating wind pressure, ηemthIs at the thEfficiency, eta of motor matched with fan under hour working conditionbpthIs at the thHourly frequency converter efficiency;
utilizing software programming, determining an initial value of a fan blade installation angle according to the maximum value of the minimum air quantity required by a fan of a cooling tower all the year round when the rated rotating speed air quantity of the fan meets the requirement of the maximum value of the minimum air quantity required by the fan of the cooling tower all the year round, carrying out hourly variable-frequency variable-speed operation according to the required air quantity under the fan blade installation angle, substituting the fan air quantity after variable-frequency variable-speed operation into a formula to calculate the total annual energy consumption, gradually increasing the blade installation angle by 0.1 degree step length, circularly calculating the total annual energy consumption according to the mode, and finally determining the optimal fixed blade installation angle of the hourly variable-frequency variable-speed operation of a fan unit;
the third scheme is as follows: annual variable-angle variable-frequency optimized operation of half-regulation fan of cooling tower
With the increase of the annual operation angle number, the operation energy consumption of the fan is gradually reduced, but the annual angle modulation cost is increased, and the annual total cost of the fan is gradually increased, so that 1 and 2 fan blade installation angle hourly frequency conversion optimal operation schemes are selected for comparison according to a large number of calculation and comparison in the third scheme; the optimal scheme of frequency conversion operation per hour under the installation angles of 1 fan blade in the whole year is as the second scheme; on the premise that the second scheme ensures the blade mounting angle with the maximum annual ventilation quantity, the mounting angles of the 1 types of blades are adjusted, and the hourly frequency conversion optimal operation scheme of the 2 types of blade mounting angles of the fan all the year is solved;
scheme three windThe installation angles of 2 blades of the machine all year are respectively alpha1、α2Let a1≥α2Rated rotational speed and air quantity of G1、G2，G1≥G2Rated speed fan efficiency of etaf1、ηf2Satisfy G1≥GmaxThe whole year T week is divided into three sections: in week 1 to t2 smallWeek and t2 is largeTurning down the installation angle of the fan blade to alpha from the week to the Tth week2The air quantity is G2Can satisfy G2≥GrThe air quantity G of the fan at rated speed is required in the two time periods2Starting to operate at variable frequency and variable speed every hour; at the t th2 small+1 week to t2 is large1 week, increase the fan blade setting angle to alpha1The air quantity is G1Can satisfy G2≤Gr≤G1At a rated speed G of the fan during the period1Starting to operate at variable frequency and variable speed every hour; determining the blade installation angle of the fan in operation every week, carrying out frequency-conversion and speed-change operation on the fan every hour every day, and the total energy consumption of the fan in operation all the year around is
Figure FDA0002615197460000051
Utilizing software programming, taking the maximum value of the minimum ventilation quantity required by the cooling tower at all times of each week as the ventilation quantity required by the cooling tower of the week in any week of the year, and setting the large angle alpha when the 2 blade mounting angles of the fan are operated according to the condition that the rated rotating speed and the air quantity of the fan meet the maximum value of the ventilation quantity required by the cooling tower of each week of the year1Is increased step by 0.1 DEG blade setting angle alpha1Setting another blade installation angle alpha of the fan according to the minimum value that the rated rotating speed and air quantity of the fan meet the air quantity required by the cooling tower every week all the year2Is increased step by 0.1 DEG blade setting angle alpha2After the mounting angles of the fan blades which operate every week all the year are determined, the operating air quantity of the fan is made to be equal to the ventilation quantity required by the cooling tower in the hour through frequency conversion in every hour, and the mounting angles of the blades at different dividing points of the iteratively selected area are substituted into a formulaCalculating the annual energy consumption, if the blade mounting angle alpha is increased every time2Alpha is not satisfied when the condition of increasing the ventilation quantity required by the cooling tower for one week is satisfied2The step length of 0.1 degree is increased again; the lowest annual energy consumption of the fan set is taken as a target to obtain the corresponding blade installation angle alpha1、α2And a variable angle time point t2 small、t2 is largeObtaining a fan frequency conversion variable angle optimized operation scheme of 2 blade mounting angles all the year round, comprising a blade mounting angle alpha1、α2Value and angle change time t2 small、t2 is largeChanging the frequency and the speed ratio in each hour;
step E: the method comprises the following steps of comparing the running energy consumption and the total running cost of equipment with the optimal fan and the adjusting mode according to different optimized running schemes of a plurality of initially selected feasible fans of the cooling tower all the year around, and carrying out accurate quantitative optimization selection according to the process:
the original fan scheme is that a fan is selected to operate at a rated rotating speed and at a designed blade installation angle all year round; the improvement scheme of the maximum ventilation fan blade angle is that a fan is selected to operate at a rated rotating speed all year round, and the maximum ventilation required by the system all year round; and D, calculating equipment operation energy consumption and total operation cost of 5 schemes of cooling tower fans with different adjustment modes all the year around in the original fan scheme, the maximum ventilation fan blade angle improvement scheme and the scheme I-scheme III in the step D, wherein the total operation cost of each scheme is equal to the sum of operation energy cost, angle modulation cost and frequency converter equipment allocation cost, comparing the annual energy consumption and the total cost of the 5 schemes in a list, and finally determining the fan with the lowest total cost and the operation scheme as the optimal fan and adjustment mode.
2. The cooling tower fan and adjustment mode accurate quantitative optimization selection method based on optimized operation according to claim 1, characterized in that in step B, the minimum ventilation volume required by the cooling tower under different environmental conditions is calculated and determined, the ventilation volume required by the cooling tower in the week in the process (4) is solved, according to different local environmental conditions all the year around, the maximum value of the minimum ventilation volume required by the cooling tower at all the moments in the week is used as the ventilation volume required by the cooling tower in the week, and the ventilation volume required by the cooling tower in the typical year around is calculated; and for any hour, calculating the hourly required ventilation quantity of each hour every day by taking the maximum value of the minimum ventilation quantity required by the cooling tower at all moments of the hour as the hourly required ventilation quantity of the cooling tower, and obtaining the hourly required ventilation quantity of the cooling tower every day all the year round.
3. The cooling tower fan and adjusting mode accurate quantitative optimization selection method based on optimized operation according to claim 1, characterized in that step E compares the running energy consumption and total running cost of various primarily selected feasible fans of the cooling tower with the optimal fan and adjusting mode accurate quantitative optimization selection, and the original fan scheme selects one fan to run at rated speed and designed blade installation angle all the year around according to the requirement of the cooling tower annual air volume; the improved scheme of the maximum ventilation quantity blade angle is used for selecting various feasible fans to operate at rated rotating speed and the blade mounting angle of the cooling tower which needs the maximum ventilation quantity all the year around.
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