CN107345777A

CN107345777A - Cooling tower half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme

Info

Publication number: CN107345777A
Application number: CN201710546566.8A
Authority: CN
Inventors: 仇宝云; 陆霞; 罗翌; 冯晓莉; 有力
Original assignee: Yangzhou University
Current assignee: Yangzhou University
Priority date: 2017-07-06
Filing date: 2017-07-06
Publication date: 2017-11-14
Anticipated expiration: 2037-07-06
Also published as: CN107345777B

Abstract

Cooling tower half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, belongs to industrial system field of energy-saving technology, calculates cooling tower ventilation drag overall；Calculate and determine cooling tower inner blower different leaves established angle operational factor, calculate and determine that annual each all cooling towers need ventilation；With the minimum target of energy consumption, annual operation blade angle number not of the same race is set, fan delivery is equal to the method for cooling tower air requirement using variable-frequency and variable-speed per hour, calculates and determine that frequency conversion becomes angle and optimizing operating scheme；Consider blower fan angle modulation and frequency converter expense, the several frequency conversions for comparing blower fan of cooling tower whole year different leaves established angle kind number become the total cost of angle and optimizing operating scheme, with the minimum principle of total cost, determine optimal annual frequency conversion angle operating scheme, including blower fan frequency conversion per hour, blade angle kind number, each blade angle numerical value and the angle time point of annual operation.Present invention determine that blower fan of cooling tower whole year frequency conversion angle optimized operation scheme energy-saving effect it is notable.

Description

Cooling tower half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme

Technical field

The invention belongs to industrial system field of energy-saving technology, is related to and sets the cooling tower half of converter plant to adjust blower fan whole year Frequency conversion become angle and optimizing operating scheme, specifically according to needed for cooling tower whole year different times minimum ventilation rate, with meet pair The cooling of water require premised on, to save cooling tower half of the fan operation total cost as target, to adjust blower fan whole year frequency conversion angle excellent Change the determination method of operating scheme.

Background technology

The energy is the important foundation of the national economic development, and because energy waste is serious, energy shortage turns into China's economy Stumbling-block preventing the development, energy-saving is one of vital task of the present economic development in China.

Recirculating cooling water system is throughout industrial departments such as metallurgy, electric power, steel, petrochemical industry, high energy consumption, wherein, cooling tower leads to Cross blower fan forced ventilation and cooling treatment is carried out to recirculated water, blower fan needs to consume substantial amounts of electric energy.At present, to circulating cooling water system Water pump assembly energy-conservation and cooling tower form research in system is more, have ignored the research of the Fan Energy-saving in cooling tower.Present Way is, according to ventilation design alternative blower fan of cooling tower and blade angle needed for annual least favorable environmental working condition, blower fan length Year is designed run under Maximum Ventilatory Volume operating mode herein.And in fact, cooling tower in the winter time and spring and autumn transition season is meets cold Minimum ventilation rate needed for heat exchange this blower fan of cooling tower whole year fixed blade established angle, turns calmly far below design Maximum Ventilatory Volume The sub-cooled ventilation method of operation of speed operation causes serious energy waste, and blower fan of cooling tower energy-saving potential is huge.

The content of the invention

The invention aims to overcome due to the ventilation operation as needed for the annual maximum of design of blower fan of cooling tower whole year Produce sub-cooled, cause the shortcomings that energy serious waste, propose that a kind of cooling tower half adjusts blower fan whole year frequency conversion and becomes angle and optimizing The determination method of operating scheme, on the premise of being included in variable-frequency and variable-speed per hour, the blade angle kind number of the annual operation of blower fan, Each blade angle numerical value and angle time point, in good time optimization change blower fan of cooling tower blade angle, save annual blower fan Operation and maintenance expense.

To realize object above, the present invention provides a kind of cooling tower half and adjusts change angle and optimizing of the blower fan based on frequency conversion per hour The accurate determination method of operating scheme, comprises the following steps：

A. cooling tower ventilation drag overall P is calculated_ZWith total impedance S.

By taking counterflow cooling tower as an example, each several part turns by air inlet, air ducting, into air-flow before liquid distribution in tower Curved, packing, liquid distribution support beam, water dispensing apparatus, water collection device, the import of air duct collar tie beam, air duct outlet diffuser composition.Its In, packing drag evaluation is as follows

A=(A₁q²+A₂q+A₃)×9.81 (2)

M=m₁q²+m₂q+m₃ (3)

P_tl=A ρ V^m (4)

In formula, P_tlFor the resistance of packing, Pa；V be filler section air average speed, m/s；Q is total water current amount, m³/h；F is packing area area, m²；Q is spray density, m³/(m²·h)；A, m is the resistance coefficient of different fillers, by 《Plastic Fill for Cooling Towers heating power and resistance performance analysis》Middle table 3 checks in；A₁、A₂、A₃、m₁、m₂、m₃For coefficient, with plastics Packing pattern is relevant with height, can be checked in from related data.

Cooling tower ventilation drag overall P_zIt is respectively with total impedance S

In formula, P_zFor cooling tower ventilation drag overall, m gas columns；S is total impedance, h²/(10⁸·m⁵)；G divulges information for cooling tower Amount, ten thousand m³/h；I is the numbering of each part in cooling tower；N is the sum of each part in cooling tower；ξ_i、v_i、F_iPoint Wei not each part coefficient of partial resistance, section air velocity m/s, cross-sectional area m in cooling tower²。

B. calculate and determine different leaves established angle real work point parameter when blower fan works in cooling tower：Flow G_j, wind Press P_j, power N_jAnd efficiency eta_j。

The performance curve of blower fan of cooling tower is provided by equipment manufacturer, blast during j-th of blade angle of blower fan Can curve can be with equation model：

In formula, j is the numbering of fan blade established angle；M is the number of the fan blade established angle of setting；P_jFor blower fan Blast during j blade angle, m gas columns；G_jFor j-th of blade angle of blower fan when air quantity, ten thousand m³/h；A_j、B_j、C_j、 D_j For constant.

Power-performance curve during j-th of blade angle of blower fan of cooling tower can be with equation model：

In formula, N_jFor j-th of blade angle of blower fan when power, kW；A_j’、B_j’、C_j’、D_j' it is constant.

According to cooling tower structure and wire feeding, determine that cooling tower needs pressure curvilinear equation to be represented by：

P=SG² (10)

To j-th of blade angle of blower fan, the jth formula and formula (10) of simultaneous equations (8), solution obtain blower fan of cooling tower the Fan operation air quantity G during j blade angle_jWith blast P_j(j=1,2,3 ..., m), common 2m amount.

By the air quantity G of the m blade angle of cooling tower inner blower tried to achieve_jBlower fan is substituted into respectively corresponds to blade angle Power-performance curvilinear equation (9) formula, is calculated m power N_j, according to the effect of formula (11) calculating m blade angle of blowing machine Rate η_fj

The m efficiency eta that formula (11) is calculated_fjIt is fitted to fan delivery~efficiency curve and air quantity~blade angle is bent Line：

η_fj=η_fj(G) (11’)

β_j=β_j(G) (11’)

In formula, η_fjFor j-th of blade angle β of blower fan_j, i.e. air quantity be G_jWhen efficiency, Fig. 1 is the cooling tower being fitted to The fan efficiency of blower fan rated speed angle acceptable operating point and blade angle relation curve.

C. minimum ventilation rate needed for cooling tower calculates determination under varying environment operating mode.

In the case that removal heat and cooling water flow are certain needed for cooled equipment, environment temperature is lower, humidity is smaller, Minimum ventilation rate needed for recirculating cooling water system cooling tower is smaller, and reducing ventilation means blower fan of cooling tower energy saving in running.It is cold But minimum ventilation rate needed for tower determines using the following method：

First, saturation of the air water vapour pressure P ", relative air humidity are calculated respectivelyApparent density ρ, the sky of humid air Gas water capacity x, humid air specific enthalpy h and saturated air enthalpy value h "；

Secondly, thermodynamic computing is carried out to counterflow cooling tower, calculates packing property number：

Ω_n'=B λ^k (12)

In formula, Ω_n' it is counterflow cooling tower work packing property number (dimensionless)；B, k is that the experiment of packing is normal Number, by《Plastic Fill for Cooling Towers heating power and resistance performance analysis》Middle table 2 checks in；λ is the air into filler (with dry air Meter) with enter filler water mass ratio, kg (DA)/kg.

Using enthalpy potential method, the cooling number of cooling tower：

In formula, Ω_nNumber (dimensionless) is cooled down for counterflow cooling tower working characteristics；K is evaporated water coefficient of bringing off heat (K<1.0, dimensionless)；C_wFor the specific heat of water, kJ/ (kg DEG C), 4.1868kJ/ (kg DEG C) is taken；H " is saturated air specific enthalpy, Heat release specific enthalpy, kJ/kg (DA) i.e. when air themperature reaches saturation state temperature t for steam partial pressure；H is humid air specific enthalpy, kJ/kg(DA)；Dt is the water temperature difference of the water inlet of infinitesimal filler and water outlet, DEG C；t₁To enter tower water temperature (DEG C)；t₂For outlet water temperature (℃)；r_t2The heat of vaporization of water, kJ/kg during to go out filler water temperature.

The calculating of cooling number preferably uses multistage Xin Puxunji decomposition methods, as follows：

Δ t=t₁-t₂ (18)

δ t=Δ t/n=(t₁-t₂)/n (19)

δ h=Δ h/n=(h₁-h₂)/n (20)

In formula, n is segments；It is t respectively to correspond to water temperature₁-δt、t₁-2δt、 t₁Saturated air enthalpy during-(n-1) δ t, kJ/kg (DA)；h"₁、h"₂It is respectively into saturated air enthalpy during outlet water temperature, kJ/ kg(DA)；h₁、h₂Respectively pass in and out the specific enthalpy of tower humid air, kJ/kg (DA)；h_mFor the average specific enthalpy of humid air in tower, kJ/kg (DA)；Δ t is disengaging tower water temperature difference, DEG C；δ t are the water temperature difference of equal segments, DEG C；Δ h is to pass in and out tower air enthalpy difference, kJ/kg (DA)；δ h be equal segments enthalpy difference, kJ/kg (DA).

When computational accuracy is less demanding, Δ t<At 15 DEG C, following simplified calculating can be used：

In formula, h "_mIt is t for corresponding coolant-temperature gage_mWhen saturated air enthalpy, kJ/kg (DA).

Such as Fig. 2, cooling task curve is represented as given different gas-water ratio λ, to complete cooling tower design condition, it is necessary to The cooling number that cooling tower has；The performance curve of filler represents cooling capacity possessed by cooling tower.When under same gas-water ratio, The cooling task of cooling tower is equal with cooling capacity, i.e. Ω_n'=Ω_nWhen, for the operating point of cooling tower.

According to different environmental working conditions, on the premise of cold is met, control disengaging coolant-temperature gage, can be drawn by tentative calculation Gas-water ratio λ corresponding to being needed at the operating point of cooling tower.This patent carries out tentative calculation, such as Fig. 3 using a kind of method constantly approached It is shown.

One gas-water ratio λ of given cooling tower₁, take multiple different outlet water temperature t₂, according to above-mentioned formula (12)~(21), Calculate multiple corresponding cooling number Ω_n, fit the conic section such as Fig. 3；According to this λ₁Obtain the leaching of cooling tower actual motion Water packing cooling characteristics number (Ω_n’)₁, meet cooling tower cooler number (Ω_n)₁Equal to packing cooling characteristics number (Ω_n’)₁Before Put, the cooling tower leaving water temperature (t of corresponding equalization point is drawn from curve₂)₁, according to regulation into and out of tower water temperature difference, obtain Inflow temperature (t₁)₁, and it is somebody's turn to do (t₁)₁Enter tower water temperature required for being generally not, now the problem of turn into：It is known enter tower water temperature t₁* With disengaging tower water temperature difference, it is desirable to gas-water ratio λ * corresponding to going out, solve with the following method.

Such as Fig. 4, pair cooling tower filler system determined, there is a gas-water ratio λ, so that it may calculated with above-mentioned a series of formula Enter tower water temperature t corresponding to one₁, t₁It is λ function, if its functional relation is Fig. 4 curve ATB, if the point T on curve ATB is institute Need coordinate (the λ *, t solved₁*), λ * can not be directly by t₁* try to achieve, solved using the method for iterative calculation point-by-point approach：It is known Curve ATB monotone decreasings, on curve ATB take gas-water ratio relatively low and higher two point A, B, and gas-water ratio value is respectively λ_A、λ_BIf It is required that enter tower water temperature t_1A>t₁*>t_1B, with gas-water ratio λ_A、λ_BCalculate respectively into tower water temperature t_1A、t_1B, two point A on curve ATB and B determines that the linear equation AB for obtaining 2 points of A, B is：

By t₁=t₁* formula (22) is substituted into, linear interpolation obtains the gas-water ratio λ of corresponding C ' points_C

Use λ_CActually enter tower water temperature t by what formula (12)~(21) calculated equalization point C on curve ATB_1C, compare into tower Water temperature calculated value t_1CWhether meet the requirement of given accuracy 0.01, if being unsatisfactory for required precision, obtained and passed through with same method The linear equation that 2 points of AC, by t₁=t₁* 2 points of AC linear equation is substituted into, linear interpolation obtains the gas-water ratio of corresponding D ' points λ_D, then use λ_DCalculate obtain equalization point D on curve ATB actually enter tower water temperature t_1D, check t_1DWhether meet that precision will Ask ... ..., until nth iteration calculates, the point N on curve infinitely approaches point T, untill meeting formula (24)

|t_1N- t₁*|≤0.01 (24)

The method can be with the solution t on iteratively faster approximating curve ATB₁* corresponding gas-water ratio λ *.

In the circulation for determining water operation, it can be deduced that corresponding ventilation under varying environment operating mode：

G_k=λ_k·Q·ρ_W/(ρ_k10000) (k=1,2,3 ..., z) (25)

In formula, G_kFor the ventilation under kth kind environmental working condition, ten thousand m³/h；ρ_kFor the atmospheric density under kth kind environmental working condition, kg/m³；ρ_wFor the density of recirculated water, kg/m³；λ_kTo enter the air (in terms of dry air) of filler under kth kind environmental working condition with entering to fill out The mass ratio of the water of material, kg (DA)/kg；Z is the kind number of varying environment operating mode.

D. cooling tower half adjusts the frequency conversion change angle and optimizing operation of blower fan whole year different leaves established angle kind number frequency conversion per hour Scheme, which calculates, to be determined.

Due to by the required Maximum Ventilatory Volume of annual least favorable environmental working condition condition-summer select blower fan model, specified turn Speed and blade angle, and because annual most time environment temperatures are relatively low relative to summer in most hot period, cooling tower institute The minimum ventilation rate needed significantly reduces, and also has larger circumstance of temperature difference in one day.With all moment cooling towers in one week The maximum of required minimum ventilation rate needs ventilation as this week cooling tower, and certain cooling tower Typical Year is led to by the needs of cycle Air quantity is as shown in Figure 5；To any hour, cooling is used as using the maximum of minimum ventilation rate needed for this hour all moment cooling towers This hour of tower needs ventilation, and typical case needs the changing rule of ventilation as shown in Figure 6 for one day.Thus, blower fan of cooling tower is pressed Rated speed and blade angle operation are also easy to produce surfusion, cause energy waste.

The fan blade used in view of current cooling tower is mostly half adjustable type, and regulation blade needs certain workload And expense, and adjust blade angle and can have certain influence to the normal use of cooling tower, therefore, fan blade should not be frequent Regulation, regulation is only capable of in 1 year for several times；And blower fan of cooling tower is run using frequency control, the first throwing except needing frequency converter equipment Money, realizes that frequency conversion only needs turning knob, easily realizes and is repeatedly adjusted with automatic frequency-conversion, will not increase expense, therefore use per hour Variable frequency adjustment, i.e. different times of the cooling tower in 1 year --- cycle selects different fan blade established angles, when making this section Phase blower fan rated speed air quantity is equal to the maximum of minimum air quantity needed for this section of period cooling tower, the different periods choosing in one day Different rotating speeds is selected, the fan delivery of this hour is equal to this hour cooling tower institute required airflow, it is minimum with power of fan per hour For target, realize that blower fan of cooling tower frequency conversion becomes angle and optimizing operation, reach the purpose for reducing fan energy consumption.

Blower fan implements frequency conversion optimization operation, it is contemplated that security, a reduction of speed, not raising speed.Fig. 7 is a typical blower fan of cooling tower The relation of air quantity, efficiency and blade angle, in the case of not speed change, the actual motion operating point of blower fan of cooling tower, one The corresponding air quantity of blade angle and a fan efficiency, 4 peak values of curve are respectively labeled as A, B, C, D, using 4 peak values as Boundary, it is divided into 5 sections, in left several first paragraph curves, with the increase of blade angle, fan efficiency more and more higher to peak efficiency Point A, this section make blower fan be run in larger blade angle as far as possible on the premise of minimum air quantity needed for cooling tower is met, Fan efficiency is reached highest, the minimum air quantity being reduced to air quantity by frequency conversion reduction of speed required for cooling tower, remain on work Condition is similar to best efficiency point, operational efficiency highest；Second segment AB curves, as the increase of blade angle, fan efficiency are first Become after drastically diminishing greatly to second peak value B, cross point B and make horizontal line friendship second segment curve in point B ', in curve AB ' segment limits, Due to being monotone decreasing curve, with the increase of blade angle, fan efficiency declines, therefore is meeting minimum wind needed for cooling tower On the premise of amount, fan blade established angle should be as small as possible；In curve BB ' sections, point B, B ' fan efficiency highest, meet it is cold But on the premise of minimum air quantity needed for tower, the fan blade established angle of B points is selected, then air quantity is dropped to by cooling by frequency conversion reduction of speed Minimum air quantity required for tower；Curve on the right of 3rd to the 5th section of curve BC, CD and D point, variation tendency is identical with AB ' sections, all It is the increase with blade angle, fan efficiency declines, therefore on the premise of minimum air quantity needed for cooling tower is met, blower fan leaf Piece established angle should be small as far as possible.

In summary, if minimum air quantity needed for cooling tower is located on the left of the A points of Fig. 7 curves, fan blade should be installed Angle is adjusted to A points, if required minimum air quantity is located at B ' B sections, fan blade established angle should be adjusted to B points, then pass through frequency conversion respectively Compressor flow is reduced to minimum air quantity needed for cooling tower by reduction of speed；If minimum air quantity needed for cooling tower is located at the AB ' of Fig. 7 curves On the right side of section or B points, then directly the blade angle as corresponding to required minimum air quantity determines on curve implements operation, without Frequency control.

Blower fan of cooling tower frequency control runs frequency converter input power

In formula, N_bjFor frequency converter input power, kW；ρ is atmospheric density, kg/m³；G is acceleration of gravity, m/s²；η_cFor wind The transmission efficiency of machine；η_bpjFrequency converter efficiency when being run for j-th of blade angle.

Frequency converter conversion efficiency is relevant with gear ratio, is represented by：

η_bp=A δ²+Bδ+C (27)

In formula, η_bpFor frequency converter conversion efficiency；δ is gear ratio；A, B, C are constant.

When on the left of minimum ventilation rate needed for cooling tower is in Fig. 7 A points and during BB ' sections, respectively by fan blade established angle A points and B points are adjusted to, makes fan efficiency highest, required air quantity is then reached using frequency conversion reduction of speed.As shown in figure 8, A in figure Point is the fan efficiency peak A points in Fig. 7, and so that required minimum ventilation rate is on the left of A points as an example, fan blade is installed Angle is adjusted to the angle of A points, using frequency conversion reduction of speed, fan condition point is moved to left down along similar operating condition parabola, makes blower fan new Operating point air quantity needs ventilation equal to the cooling tower hour, and new operating mode is similar to former operating mode A, and fan efficiency keeps constant, On the premise of meeting cooling tower needs ventilation, blower ventilation amount is reduced, improves operational efficiency, reached the mesh of energy-conservation 's.

Blower fan fall-back, the general gear ratio that limits is between 0.6~1, it is believed that the affinity operating points effect after reduction of speed Rate is equal with before reduction of speed, if such as the A in Fig. 8₁Point gear ratio is δ_A1=0.6, air quantity G_A1, power N_A1, fan efficiency is η_fA1, η_fA1=η_fA=η_fmax；It is G that if cooling tower, which needs ventilation,_A2, G_A2<G_A1, consider fan frequency conversion speed governing in A₂Point operation, by In δ_A2<0.6, η_fA2<η_fA1, but η_fA2Compared with η_fA1Decline very little, in addition, and A₁Point is compared, A₂Point motor efficiency η_emA2, transmission effect Rate η_cA2With frequency converter efficiency eta_bpA2Vary less, and due to A₂Point air quantity is significantly less than A₁Point air quantity, blower fan affinity operating points Shaft power is directly proportional to the cube of air quantity, thus A₂The shaft power N of point_A2Significantly less than A₁The shaft power N of point_A1, by formula (26) Know, the frequency converter input power N of A2 points_bA2Significantly less than A₁The frequency converter input power N of point_bA1, it should variable frequency adjustment blower fan turns Speed is in A₂Point operation.

Whole year using week as chronomere, it is assumed that certain section of duration several weeks to it is tens of all in the period of in, blower fan is with a kind of blade Established angle is run, it is desirable to which operation air quantity of this section of period inner blower under rated speed, which is equal to, to be needed in this section of period cooling tower each week The maximum of ventilation, set this week fan blade established angle β_tw, rated speed air quantity G_twAnd fan efficiency η_ftw, it is basic herein Upper progress frequency conversion per hour, the conversion efficiency of each hour are

In formula, η_bpthFor t_hThe frequency converter efficiency of hour fan operation；G_thFor t_hHour fan operation air quantity, ten thousand m³/ H, its value are equal to ventilation needed for this hour cooling tower；G_twFor t_wAll fan blade established angles are β_twWhen rated speed when wind Amount, ten thousand m³/h。

In one day, the motor efficiency under each hour load is

In formula, η_emthFor t_hHour fan operation auxiliary motor efficiency；η_NFor motor rated efficiency；β_thFor t_h The motor load rate of hour；K is the ratio of motor fixed loss coefficient and variable loss coefficient.K size：2 is extremely asynchronous Motor is 2；The asynchronous motor of 4 poles and 6 poles is 1；8 poles and the above for 0.5.According to《Asynchronous motor in arbitrary loads Under efficiency and power factor calculating》Middle table 1 checks in b values.

T_wOne day energy consumption of all blower fan systems：

In formula, A_twFor blower fan system t_wMonday day energy consumption, kWh；ρ_thFor t_hThe atmospheric density of hour, kg/m³； P_thFor t_hThe fan operation blast of hour, m gas columns；η_ftwFor t_wAll fan operation efficiency.

If t_wThe changing rule of ventilation by the hour is identical needed for all cooling towers every day, then the annual fortune of blower fan of cooling tower Row energy consumption and energy expenditure：

Y_z=A_z·y (33)

In formula, A_zFor the annual operation power consumption of blower fan of cooling tower, kWh；t_wFor the cycle of whole year operation；T is annual operation week Number, it is continuous to run 1 year in terms of 52 weeks；Y_zFor blower fan of cooling tower whole year energy expenditure, member；Y is electricity Unit Price, member/(kWh).

Large fan blade is half adjustable type, and manual adjustment blade angle is, it is necessary to certain expense, it is determined that blower fan becomes During the frequency conversion optimization operating scheme of angle, it is contemplated that the expense of blade angle adjustment.

Blower fan implements converting operation per hour, in the case where annual fan operation blade angle number is certain, angle Time point is different, and the annual operation power consumption of blower fan is also different, using the time point of annual blower fan angle as variable, lists annual wind Machine runs the calculating formula of power consumption, is calculated by Optimized Iterative, obtains the fan operation consumption of the annual blower fan blade angle number Electricity A_zMinimum value and its corresponding optimal blade angle and angle time point.

Programming carries out Optimized Iterative calculating, first inputs air quantity, the wind of blower fan of cooling tower rated speed angle acceptable operating point Pressure, power and efficiency, then institute's required airflow and corresponding atmospheric density input per hour by each week of cooling tower under annual environmental working condition, By taking annual 2 kinds of fan blade established angles operation as an example, since the adjustable minimum blade established angle of blower fan try generation, setting 0.1 ° of angle step, take needs of the maximum of minimum ventilation rate needed for all moment cooling towers in one week as this week cooling tower Ventilation, compare 2 kinds of blade angles in examination generation corresponding to air quantity whether meet the ventilations of each all needs, if satisfied, then this Week is run under such a fan blade established angle, if not satisfied, then being run under another fan blade established angle, it is determined that complete After the fan blade established angle that year is run weekly, by frequency conversion per hour, fan operation air quantity is set to be needed equal to this hour of cooling tower The ventilation wanted.

The daily variable-frequency and variable-speed per hour of blower fan, although speed change rear fan energy consumption reduces, due to adding frequency converter after frequency conversion Energy consumption, so the forward and backward frequency converter input power size of frequency conversion need to be compared, if frequency converter input power increases after variable-frequency and variable-speed, Illustrate the underpower of blower fan reduction to compensate the increase power of frequency converter, the hour just should not variable-frequency and variable-speed operation.

Annual fan operation energy consumption and energy expenditure are calculated with the method operation；Tried again by step length for blower fan again Blade angle, annual fan operation energy consumption and energy expenditure are recalculated in aforementioned manners, all blades of blower fan are installed After angle whole examination generation terminates, compare the scheme of annual the fan operation energy consumption and energy expenditure that draw minimum, and obtain 2 kinds of blowing machine The optimal blade angle of blade angle operation and angle time point.

Change blower fan whole year blade angle kind number re-optimization to calculate, obtain the wind of annual various blade angle kind numbers Machine frequency conversion becomes angle and optimizing operating scheme.

Calculate air quantity expression formula needed for cooling tower each week under the annual environmental working condition for drafting corresponding diagram 5

G_r=G_r(t_w) (34)

The annual a kind of blade angle frequency conversion per hour daily optimization operation of scheme one

Cooling tower each week needs ventilation as shown in Fig. 9 block diagrams in 1 year, is meeting that annual cooling tower maximum demand leads to Air quantity G_maxOn the premise of, a kind of blade angle β of the annual operation of setting blower fan₁, rated speed fan efficiency is η_f1, air quantity For G₁, G can be met₁≥G_rRequirement, blower fan under this blade angle daily per when frequency conversion variable-speed operation, frequency conversion rear fan wind Amount needs ventilation equal to cooling tower each hour.With reference to the fan efficiency of figure 1 and blade angle relation curve, transported with annual blower fan The minimum target of row total energy consumption, determine the optimal blade angle of the annual a kind of blade angle operation of blower fan.

Annual fan operation total energy consumption is

With the annual operation minimum target of total energy consumption of blower fan, tentative calculation of being programme to formula (35), it is annual optimal to solve determination Rated speed operation air quantity, corresponding blade angle, make operation total cost minimum.

The annual 2 kinds of blade angles frequency conversion per hour daily optimization operation of scheme two

As shown in Figure 10, converting operation, guarantee are annual least per hour from annual 2 kinds of blade angles for this programme blower fan The ventilation of sharp environmental working condition, the optimal blade angle of the annual 2 kinds of blade angles operation of setting blower fan is respectively β₁、β₂, wind Machine rated speed air quantity is respectively G₁、G₂If β₁≥β₂, G₁≥G₂, fan efficiency is respectively η_f1、η_f2, it was divided into three by annual T weeks Section：At the 1st week to t_{2 is small}Week and t_{2 is big}Zhou Zhi T week, fan blade established angle is turned down to β₂, air quantity G₂G can be met₂≥G_r Requirement, the two periods blower fan is with rated speed air quantity G₂Start converting operation per hour；In t_{2 is small}+ 1 is all to t_{2 is big}- 1 In week, fan blade established angle is tuned up to β₁, air quantity G₁G can be met₂≤G_r≤G₁Requirement, the period blower fan is with rated speed G₁Start converting operation per hour.The blade angle that blower fan is run weekly is determined, frequency conversion per hour daily is implemented to blower fan Variable-speed operation, annual fan operation total energy consumption are

With the minimum target of the annual total operation energy consumption of blower fan, with fan blade angle time separation rated speed air quantity G₁、G₂For variable, to different air quantity G₁、G₂Value, calculating formula (36) energy consumption of programming, choose the minimum G of energy consumption₁、G₂Value, draws Corresponding blade angle β₁、β₂And angle time point t_{2 is small}、t_{2 is big}, the fan frequency conversion angle for obtaining annual 2 kinds of blade angles is excellent Change operating scheme.

The annual 3 kinds of blade angles frequency conversion per hour daily optimization operation of scheme three

As shown in figure 11, this programme considers 3 kinds of blade angle β of whole year₁、β₂、β₃Operation, corresponds to specified turn of blower fan respectively The efficiency eta of speed_f1、η_f2、η_f3, air quantity G₁、G₂、G₃If β₁≥β₂≥β₃, G₁≥G₂≥G₃.It was divided into five sections by annual T weeks：1st week extremely T_{3 is small}Week and t_{3 is big}Zhou Zhi T week, blower fan is with blade angle β₃Operation, the air quantity G of corresponding rated speed₃G can be met₃≥G_r Requirement, the period blower fan is from air quantity G₃Start converting operation per hour；T_{3 is small}+ 1 is all to t_{2 is small}Week and t_{2 is big}Zhou Zhi t_{3 is big}In -1 week, blower fan is with blade angle β₂Operation, the air quantity G of corresponding rated speed₂G can be met₃≤G_r≤G₂Requirement, should Period blower fan is from air quantity G₂Start converting operation per hour；T_{2 is small}+ 1 is all to t_{2 is big}In -1 week, blower fan is with blade angle β₁ Operation, the air quantity G of corresponding rated speed₁G can be met₂≤G_r≤G₁Requirement, the period blower fan is from air quantity G₁Start per hour Converting operation.The blade angle that blower fan is run weekly is determined, implements frequency conversion per hour daily.Annual fan operation total energy consumption For

With the minimum target of the annual total operation energy consumption of blower fan, with fan blade angle time separation rated speed air quantity G₁、G₂、 G₃For variable, to different air quantity G₁、G₂、G₃Value, calculating formula (37) energy consumption of programming, choose the minimum G of energy consumption₁、 G₂、G₃Value, draw corresponding blade angle β₁、β₂、β₃And angle time point t_{3 is small}、t_{2 is small}、t_{2 is big}、t_{3 is big}, obtain annual 3 kinds of blades The fan frequency conversion of established angle becomes angle and optimizing operating scheme.

The annual 4 kinds of blade angles frequency conversion per hour daily optimization operation of scheme four

As shown in figure 12, this programme is using annual 4 kinds of fan blade established angles operation, by the side of scheme two and scheme three Method, the annual operation total energy consumption calculating formula of blower fan is listed, with the annual operation minimum target of total energy consumption of blower fan, program calculation solves, Determine optimal fan blade established angle β₁、β₂、β₃、β₄, corresponding rated speed air quantity G₁、G₂、G₃、G₄And the corresponding angle time Point.The blower fan of cooling tower frequency conversion that annual 5 kinds, 6 kinds ... blade angles can be obtained with same method becomes angle and optimizing operation side Case.

E. cooling tower half adjusts the frequency conversion change angle and optimizing operation of blower fan whole year different leaves established angle kind number frequency conversion per hour Scheme expense compares to be determined with annual optimal frequency conversion angle operating scheme.

The frequency conversion of blower fan of cooling tower whole year different leaves established angle kind number frequency conversion per hour becomes angle and optimizing operating scheme expense, Including operation energy expenditure, angle modulation expense, compared with not frequency conversion, frequency converter original equipment expense is added.

Scheme one is annual based on a kind of daily converting operation per hour of blade angle, does not have angle modulation expense, converting operation There is frequency converter initial cost, frequency converter regulation is without expense, therefore blower fan of cooling tower runs annual total cost and is equal to fan operation energy Source expense and frequency converter original equipment expense sum.

Scheme two to scheme four is annual based on the daily converting operation per hour of different leaves established angle kind number, according to fortune The angle number accumulation calculating angle modulation expense of row scheme, converting operation has frequency converter equipment expense, therefore blower fan of cooling tower is annual total Expense is equal to fan operation energy expenditure, angle modulation expense and frequency converter original equipment expense allocation sum.

Finally, annual design blade angle operating scheme former to blower fan, annual cooling tower maximum demand ventilation blade The equipment operation energy expenditure of totally 6 kinds of schemes and operation total cost are compared to scheme four for established angle operating scheme and scheme one Compared with the final scheme for determining that total cost is minimum becomes angle and optimizing operating scheme for optimal frequency conversion.

Brief description of the drawings

Fig. 1 is the fan efficiency and blade angle graph of a relation of blower fan of cooling tower rated speed angle acceptable operating point.

Fig. 2 is cooling tower cooler task curve and carrier performance curve map.

Fig. 3 is cooling tower cooler number and outlet water temperature graph of a relation.

Fig. 4 is that cooling tower equalization point calculates iterative approach method figure.

Fig. 5 is that Typical Year cooling tower needs spirogram of divulging information by cycle.

Fig. 6 is cooling tower typical case day required ventilation spirogram per hour.

Fig. 7 is that variable-frequency and variable-speed optimization operating scheme when cooling tower half adjusts blower fan different leaves established angle determines method Figure.

Fig. 8 is that the regulation fan frequency conversion speed change optimization operation gear ratio of cooling tower half determines figure.

Fig. 9 is that annual a kind of blade angle frequency conversion per hour daily optimizes the fan delivery of operating scheme and blade is installed Angle figure.

Figure 10 is that annual 2 kinds of blade angles frequency conversion per hour daily optimizes the fan delivery of operating scheme and blade is installed Angle figure.

Figure 11 is that annual 3 kinds of blade angles frequency conversion per hour daily optimizes the fan delivery of operating scheme and blade is installed Angle figure.

Figure 12 is that annual 4 kinds of blade angles frequency conversion per hour daily optimizes the fan delivery of operating scheme and blade is installed Angle figure.

Figure 13 is the air quantity and blast, air quantity and power-performance curve map of LF-42 type blower fans of the embodiment of the present invention.

Figure 14 is that blower fan of cooling tower of embodiment of the present invention angle runs blade angle and air quantity graph of relation.

Figure 15 is that blower fan of cooling tower rated speed of embodiment of the present invention angle runs blast and air quantity graph of relation.

Figure 16 is blower fan of cooling tower of embodiment of the present invention rated speed angle operational efficiency and air quantity graph of relation.

Figure 17 is the fan delivery and blade angle figure that the frequency conversion of the present embodiment Typical Year becomes angle and optimizing operating scheme three.

Figure 18 is the gear ratio figure for each hour converting operation in typical day that the present embodiment frequency conversion becomes angle and optimizing operating scheme three.

Embodiment

Technical scheme is used below, and the invention will be further described in conjunction with the accompanying drawings and embodiments, but this reality Example is applied to should not be construed as limiting the invention.

There are 1 LDCM-800SC type cooling tower, local atmospheric pressure 754mmHg, density 1.13kg/ in certain workshop of chemical plant one m³, cooling water flow 800m^3/h.Blower fan model LF-42, half is adjusted, with threephase asynchronous machine Y180L-4, rated power 22kW, Rated current 43A, electric efficiency 90%, rotating speed 1470r/min, with VFD220CP43B-21 type blower fan water pump special converters. Cooling tower is furnished with LJ3 type reductors, its efficiency 92%.Local 0.6 yuan of electricity Unit Price/(kWh).

Former operating scheme is：Blower fan whole year is run with 13 ° of blade angles, and operation air quantity is 45.3769 ten thousand m³/ h, operation Power is 18.4877kW, motor input power 21.88kW, and whole year runs total power consumption 191144kWh, and total energy source cost is used 114686 yuan.

Known LDCM-800SC types cooling tower body structure：Packing area area 46m², air-admitting surface 46m², air ducting Length 3m；The net draught area 41m of liquid distribution², the net draught area 43m of water dispensing apparatus², the net draught area 43m of water collection device², Air duct inlet -duct area 26m², air duct throat opening area 14.12m², air duct discharge area 25.53m², packing is inclined ladder wave mode, wind 120 ° of cylinder import taper angle, 60 ° of outlet flaring angle.

This example selects 1.0m ramp wave water pouring fillers, and it is 17kg/ (m to obtain spray density q by formula (1)²·h)；By《Cooling Tower plastic water showering filling heating power and resistance performance analysis》Middle table 3 can check in A₁、A₂、A₃Respectively 0.00054,0.02372, 0.38310, m₁、m₂、m₃Respectively 0.00422, -0.12560,2.9710, substitute into formula (2), formula (3) obtains A=9.2449, m= 2.05538；Packing resistance is calculated by formula (4):

P_tl=A ρ V^m=9.2449 × 1.13 × 2.86^2.05538=90.57Pa

According to the area of section and resistance coefficient of each part in cooling tower, the speed of each section can be obtained by formula (5) v_i, substitute into formula (6) and draw cooling tower ventilation drag overall：

By cooling tower drag overall P_zSubstitution formula (7) obtains total impedance

B. calculate and determine different leaves established angle real work point parameter when blower fan works in cooling tower：Flow G_j, wind Press P_jAnd efficiency eta_j。

Figure 13 is the air quantity and blast, air quantity and power-performance for the LF-42 type blower fans that cooling tower of the embodiment of the present invention uses Curve, obtained by fitting, the coefficient A of 13 ° of blade angle air quantity-wind pressure property curvilinear equations₁₃、B₁₃、C₁₃、D₁₃Respectively- 0.000069th, 0.0057, -0.4205,24.4712, formula (8) is substituted into, obtains 13 ° of blade angle air quantity-wind pressure properties Curvilinear equation is

P₁₃=-0.000069G³+0.0057G²-0.4205G+24.4712

Obtained by fitting, the coefficient A of 13 ° of blade angle air quantity-power-performance curvilinear equations₁₃’、B₁₃’、C₁₃’、D₁₃’ Respectively 0.0005, -0.0723,3.1266, -24.1831, formula (9) is substituted into, obtains 13 ° of blade angle air quantity-power Performance curve equation is

N₁₃=0.0005G³-0.0723G²+3.1266G-24.1831

Cooling tower total impedance S is substituted into formula (10), obtaining cooling tower needs pressure curvilinear equation：

P=0.00514G²

The intersection point for needing pressure curve and fan delivery-wind pressure property curve is the operating point of blower fan.Simultaneous side Journey solves to obtain the m of actual motion operating point flow G=45.3769 ten thousand of 13 ° of blade angles³/ h, blast P=10.6742m gas Post, power N=18.4877kW.

The performance curve of remaining each blade angle of blower fan is fitted in aforementioned manners, from 2 ° to 22 °, at interval of 0.1 ° of fitting One curve, totally 201 air quantity-wind pressure property curvilinear equation, respectively simultaneous need pressure fitting equation (10), solve 201 operating point parameters are obtained, as shown in Figure 14, Figure 15.

By the air quantity G of 201 blade angles of cooling tower inner blower tried to achieve_jBlower fan is substituted into respectively corresponds to blade angle Power-performance curvilinear equation (9) formula, 201 power N are calculated_j, 201 blade installations of blowing machine are calculated according to formula (11) Efficiency eta during angle_fjAs shown in figure 16.

It is calculated as follows by taking an environmental working condition as an example：

Environmental working condition：Atmospheric pressure 100.56kPa, dry-bulb temperature：27 DEG C, wet-bulb temperature：25 DEG C, will according to equipment cooling Ask, control into tower water temperature and be up to 45 DEG C, be 10 DEG C into and out of tower water temperature difference.Saturated steam partial pressure corresponding to 27 DEG C and 25 DEG C Power is respectively P_d"=3.5631kPa, P_s"=3.1655kPa, relative air humidity areThe apparent density of humid air is ρ=1.1569kg/m³, air humidity content is x=0.0193kg/kg (DA).

As shown in Fig. 2 when under the cooling task curve and carrier performance curve intersection of cooling tower, i.e., same gas-water ratio Ω_n'=Ω_nWhen, for the operating point of cooling tower.In order to obtain the matching point of cooling tower, tentative calculation is carried out, first takes 3 groups of data： (1)t₁=46 DEG C, t₂=36 DEG C, t_m=41 DEG C, λ=0.39kg (DA)/kg；(2)t₁=47 DEG C, t₂=37 DEG C, t_m=42 DEG C, λ =0.39kg (DA)/kg； (3)t₁=48 DEG C, t₂=38 DEG C, t_m=43 DEG C, λ=0.39kg (DA)/kg.Using first group of data as Example is calculated as follows：

It is h to be calculated into tower humid air property₁=76.362kJ/kg (DA), related data is substituted into formula (14) and steamed The heat gain coefficient that shampoo amount is taken away is

Obtaining out tower humid air property by formula (16) is

The average enthalpy that humid air in tower is obtained by formula (17) is

t₁、t₂、t_mCorresponding saturated steam partial pressure is respectively P_t1"=10.0832kPa, P_t2"=5.939kPa, P_tm” =7.776kPa, corresponding saturated air specific enthalpy is respectively h₁"=225.4689kJ/kg (DA), h₂"=136.4071kJ/kg (DA)、 h_m"=175.5128kJ/kg (DA).

The cooling number that substitution formula (21) obtains cooling tower is

According to the method described above, other two groups of data are calculated, are calculated as shown in table 1：

1 λ of table=0.39kg (DA)/kg equalization points A calculating tables of data

Arrangement obtains (1) t₂=36 DEG C, Ω_n=1.0503；(2)t₂=37 DEG C, Ω_n=0.8606；(3)t₂=38 DEG C, Ω_n =0.7258.Pass through this 3 groups of data, such as Fig. 3, matched curve：

From 1.0m ramp wave water pouring fillers, by《Plastic Fill for Cooling Towers heating power and resistance performance analysis》Middle table 2 B, k-factor are checked in, substitution formula (12) obtains packing property number and is

Ω_n'=B λ^k=1.60 × 0.39^0.64=0.8758

To meet cooling number Ω_nEqual to characteristic quantity Ω_n', make Ω_n=Ω_n', solution equalization point t₂=36.9078 DEG C.Therefore it must put down Weigh point A points, and coordinate is (0.39,46.9078).

λ=0.49kg (DA)/kg 3 groups of data, (1) t are taken again₁=43 DEG C, t₂=33 DEG C, t_m=38 DEG C, λ=0.49kg (DA)/kg； (2)t₁=44 DEG C, t₂=34 DEG C, t_m=39 DEG C, λ=0.49kg (DA)/kg；(3)t₁=45 DEG C, t₂=35 DEG C, t_m =40 DEG C, the kg (DA) of λ=0.49/kg.Recalculate as procedure described above, it is specific to calculate as shown in table 2：

2 λ of table=0.49kg (DA)/kg equalization points B calculating tables of data

Arrangement obtains (1) t₂=33 DEG C, Ω_n=1.4689；(2)t₂=34 DEG C, Ω_n=1.1625；(3)t₂=35 DEG C, Ω_n =0.9566.Pass through this 3 groups of data, such as Fig. 3, matched curve：

It is Ω that substitution formula (12), which obtains packing property number,_n'=B λ^k=1.60 × 0.49^0.64=1.0136.Make Ω_n=Ω_n', Solve equalization point t₂=34.6691 DEG C.Therefore another equalization point B is drawn, coordinate is (0.49,44.6691).

Such as Fig. 4, line style connects equalization point A, B, linear equation t_1ABThe λ+55.63873 of=﹣ 22.387.

Control into tower water temperature and be up to 45 DEG C, the tower coolant-temperature gage that enters finally approached a little is t₁*=45 DEG C, t is made₁*=t_1AB= 45 DEG C, substitution linear equation is formula (22), solves formula (23) C ' points λ_C’=0.4752kg (DA)/kg, C ' point is according to 2 points of A, B What linear change was tried to achieve, in turn by λ_C’=0.4752kg (DA)/kg recalculates to obtain equalization point C on curve in aforementioned manners The outlet water temperature t of point₂=34.9708 DEG C, then enter tower water temperature t₁=44.9708 DEG C, therefore C point coordinates is (0.4752,44.9708), Substitution formula (24), | t_1C-t₁* |=0.0292>0.01, precision is unsatisfactory for requiring, need to continue to iterate to calculate；Each point on comparison curves Position, required equalization point T lists AC linear equations, and use t between nearest point A, C₁*=45 DEG C substitution, is asked Invocation point D ' abscissa is λ_D’=0.4739kg (DA)/kg, then by λ_D=0.4739kg (DA)/kg is recalculated in aforementioned manners Obtain the outlet water temperature t of equalization point D points on curve₂=35.0037 DEG C, D point coordinates is (0.4739,45.0037), substitutes into formula (24), | t_1D-t₁* |=0.0037<0.01, precision meets to require, substitutes into the ventilation that formula (25) obtains calculating operating mode：

G_k=λ_k·Q·ρ_w/(ρ_k10000)=m of 0.4739 × 800 × 1000/1.1569=32.7634 ten thousand³/h

Minimum ventilation rate needed for the environmental working condition cooling tower of annual different time is calculated according to the method described above.

The present embodiment, using annual daily converting operation per hour, it is annual using different leaves installation to solve determination to blower fan The frequency conversion of angle kind number becomes angle and optimizing operating scheme.

The present embodiment selects asynchronous motor, and its frequency converter efficiency and gear ratio δ relation are according to formula (27) fitting side Cheng Wei

η_bp=-0.0266 δ²+0.0992δ+0.9054

Such as Fig. 9, meeting annual maximum quantity of wind G_max=41.2454 ten thousand m³On the premise of/h, with the annual operation total energy of blower fan Minimum target is consumed, the annual optimal blade angle of tentative calculation blowing machine is 10.1 °, i.e. B points in Fig. 7, blower fan rated speed wind Measure as 41.9791 ten thousand m³/ h, fan efficiency 80.73%, converting operation per hour is carried out daily to blower fan, makes fan delivery Equal to cooling tower institute's required airflow per hour.In tentative calculation, if frequency converter input power increases after frequency conversion, hour not frequency conversion fortune OK.Substitution formula (35), annual fan operation total energy consumption are A_z=48289kWh.

As shown in Figure 10, this programme blower fan is annual with blower fan from converting operation per hour under annual 2 kinds of blade angles The minimum target of total energy consumption is run, 2 kinds of optimal blade angles of tentative calculation blowing machine operation are respectively 10.1 ° and 6 °.1st week extremely 22nd week and the 38th week to the 52nd week, blower fan was run with 6 ° of blade angles, i.e. A points in Fig. 7, blower fan rated speed air quantity For 35.9505 ten thousand m³/ h, fan efficiency 88.85% meet the required air quantity of the two periods cooling tower, blower fan from 35.9505 ten thousand m³/ h air quantity starts converting operation；23rd week to the 37th week, blower fan was run with 10.1 ° of blade angles, blower fan Rated speed air quantity is 41.9791 ten thousand m³/ h, fan efficiency 80.73%, meet the required air quantity of the period cooling tower, Blower fan is from 41.9791 ten thousand m³/ h air quantity starts converting operation.Substitution formula (36), annual fan operation total energy consumption A_z= 46796kW·h。

Such as Figure 11, this programme blower fan selects annual 3 kinds of blade angles converting operation per hour, total with the annual operation of blower fan The minimum target of energy consumption, 3 kinds of optimal blade angles of tentative calculation blowing machine operation are respectively 10.1 °, 6.8 ° and 6 °.Such as Figure 17 institutes Show, the 1st week to the 22nd week and the 38th week to the 52nd week, blower fan is run with 6 ° of blade angles, and fan delivery is 35.9505 ten thousand m³/ h, fan efficiency 88.85%, thus air quantity starts converting operation to blower fan；23rd week and the 37th week, blower fan was with 6.8 ° of blades Established angle is run, and fan delivery is 37.0575 ten thousand m³/ h, fan efficiency 83.60%, thus air quantity starts frequency conversion fortune to blower fan OK；Run within 24th week to the 36th week, blower fan is run with 10.1 ° of blade angles, and fan delivery is 41.9791 ten thousand m³/ h, blower fan Efficiency is 80.73%, and thus air quantity starts converting operation to blower fan.The fan frequency conversion speed change of each hour is such as schemed in 27th Monday day Shown in 18.Substitution formula (37), calculate annual fan operation total energy consumption is A_z=46675kWh.

Such as Figure 12, this programme blower fan uses annual 4 kinds of blade angles converting operation per hour, total with the annual operation of blower fan The minimum target of energy consumption, programming tentative calculation solve, and it is 10.1 °, 7.5 °, 6.8 ° and 6 ° to determine 4 kinds of optimal blade angles of blower fan, the Run to the 22nd week and the 38th week to the 52nd week, blower fan with 6 ° of blade angles within 1 week, fan delivery is 35.9505 ten thousand m³/ h, Fan efficiency is 88.85%, and thus air quantity starts converting operation to blower fan；23rd week and the 37th week, blower fan was installed with 6.8 ° of blades Angle is run, and fan delivery is 37.0575 ten thousand m³/ h, fan efficiency 83.60%, thus air quantity starts converting operation to blower fan；The 24 weeks and the 36th week, blower fan was run with 7.5 ° of blade angles, and fan delivery is 38.0542 ten thousand m³/ h, fan efficiency are 81.13%, thus air quantity starts converting operation to blower fan；25th week to the 35th week, blower fan was run with 10.1 ° of blade angles, wind Fan delivery is 41.9791 ten thousand m³/ h, fan efficiency 80.73%, thus air quantity starts converting operation to blower fan.Calculate annual Fan operation total energy consumption is A_z=44323kWh.

E. cooling tower half adjusts the frequency conversion change angle and optimizing operation of blower fan whole year different leaves established angle kind number frequency conversion per hour Scheme expense compares becomes the determination of angle and optimizing operating scheme with annual optimal frequency conversion.

The half regulation blower fan that the present embodiment cooling tower is selected, 2 °~22 ° of blade angle scope are cold applied to the present embodiment But tower, best efficiency point is at 6 °, and the annual blade angle kind number used of blower fan of cooling tower is different, and frequency conversion becomes angle and optimizing operation side Several respects expense of case is also different, and blower fan is determined to blower fan original operating scheme, by cooling tower whole year maximum demand ventilation Blade angle scheme, the annual operation energy consumption of totally 6 kinds of schemes, energy consumption cost, the angle modulation of scheme one to the frequency conversion per hour of scheme four Expense, frequency converter expense and total cost are compared, wherein, by 0.6 yuan/(kWh) calculating, half adjusts blower fan adjusts electricity Unit Price Angle is once cost with 1000 yuan；4500 yuan of the VFD220CP43B-21 type blower fan water pump special converters first cost of selection, Service life 10 years, 500 yuan of residual value, the frequency converter expense for sharing each year are 400 yuan, and each scheme expense compares such as table 3.

Frequency conversion angle optimization operating scheme whole year is taken during table 3 the present embodiment blower fan of cooling tower, 6 ° of blade angle efficiency highests With comparing

Such as table 3, to each converting operation scheme per hour, blower fan of cooling tower optimization fortune is determined according to operation energy consumption is minimum The size and run time of row blade angle；To all operating schemes, according to including fan operation energy expenditure, angle modulation expense It is minimum with the total cost of frequency converter expense allocation, determine optimal frequency conversion angle operating scheme.

Compared to former scheme, blade angle is adjusted to 9.6 ° of maximum quantity of wind needed for cooling tower whole year, annual energy cost With saving 17.36%；For scheme one to scheme four using the optimization operation of frequency conversion per hour, it is left that energy expenditure saving rate reaches 75% The right side, energy-saving effect are fine；With the increase for the blade angle kind number that whole year uses, frequency conversion angle operation energy expenditure slightly subtracts It is small, it is contemplated that the increase of angle modulation expense, total cost gradually increase on the contrary with the increase of angle modulation number, so, scheme one：Whole year is one Optimal 10.1 ° of the blade angle of kind, the optimization operating scheme of frequency conversion per hour, it is the annual optimal frequency conversion angle fortune of blower fan of cooling tower Row scheme, compared with former scheme, total cost saves 74.39%.

If scheme two to the angle modulation expense of scheme four drops to 800,1600,2400 yuan respectively, its annual total cost difference For 29261,30001,30784 yuan, two -2 kinds of blade angle schemes of scheme are that optimal frequency conversion becomes angle and optimizing operating scheme, entirely Annual total cost saves 74.49%.

Claims

1. cooling tower half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, it is characterised in that including following Step：

Step A:Calculate cooling tower ventilation drag overall P_ZWith total impedance S；

Step B：Calculate and determine different leaves established angle real work point parameter when blower fan works in cooling tower：Flow G_j, blast P_j, power N_jAnd efficiency eta_j；

Step C：Minimum ventilation rate needed for cooling tower, which calculates, under varying environment operating mode determines；

Step D：The frequency conversion that cooling tower half adjusts the frequency conversion per hour of blower fan whole year different leaves established angle kind number becomes angle and optimizing operation Scheme, which calculates, to be determined；

Step E：The frequency conversion that cooling tower half adjusts blower fan whole year different leaves established angle kind number variable-frequency and variable-speed per hour becomes angle and optimizing Operating scheme expense compares becomes the determination of angle and optimizing operating scheme with annual optimal frequency conversion.

2. cooling tower according to claim 1 half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, Characterized in that, the ventilation drag overall of cooling tower described in step A P_ZIt is as follows with total impedance S solution procedure：

By taking counterflow cooling tower as an example, each several part is filled out by air inlet, air ducting, into rocket motor, water drenching before liquid distribution in tower Material, liquid distribution support beam, water dispensing apparatus, water collection device, the import of air duct collar tie beam, air duct outlet diffuser composition, packing resistance are P_tl=A ρ V^m, each several part resistance is cumulative to try to achieve cooling tower drag overall P_Z, P_ZSolution formula Total impedance S solution formulaWherein V is the air mean flow rate of filler section, and A, m are different filler resistance coefficients, I is each several part local resistance numbering, ξ in tower_iFor cooling tower each several part coefficient of partial resistance, v_iFor each several part section air in tower Mean flow rate, ρ are atmospheric density, kg/m³, g is acceleration of gravity, m/s², G is cooling tower ventilation, ten thousand m³/h。

3. cooling tower according to claim 1 half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, Characterized in that, the flow of different leaves established angle real work point when blower fan works in cooling tower is determined described in step B G_j, blast P_j, power N_jAnd efficiency eta_jSolution procedure it is as follows：Simultaneous blower fan of cooling tower wind pressure property curvilinear equationPressure curvilinear equation P=SG is needed with cooling tower², solve and obtain blower fan j-th Blade angle luck sector-style amount G_jWith blast P_j(j=1,2,3 ..., m), wherein j number for fan blade established angle, and m is to set The number of fixed fan blade established angle, P_jFor j-th of blade angle of blower fan when blast, G_jFor j-th of blade installation of blower fan Air quantity during angle, A_j、B_j、C_j、D_jFor constant；The fan delivery G that will be tried to achieve_jThe power of fan of corresponding blade angle is substituted into respectively Performance curve equationTry to achieve the fortune of blower fan m blade angle in cooling tower Row power N_j, wherein N_jFor the power of j-th of blade angle of blower fan, A_j’、B_j’、C_j’、D_j' it is constant；By m blade of blower fan The air quantity G of established angle_j, blast P_jWith power N_jFormula is substituted into respectivelyCalculate blower fan in cooling tower The efficiency eta of m blade angle_fj, by G_j~η_fjIt is fitted to blower fan relation curve η of operating efficiency and air quantity in cooling tower_fj =η_fjAnd the relation curve β of blade angle and air quantity (G)_j=β_j(G)。

4. cooling tower according to claim 1 half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, Characterized in that, minimum ventilation rate needed for cooling tower calculates the solution procedure determined such as under varying environment operating mode described in step C Under：

(1) according to annual different environmental working condition, saturation of the air water vapour pressure P ", relative air humidity are calculated respectivelyWet sky The apparent density ρ of gas, air humidity content x, the value h " of humid air specific enthalpy h and saturated air enthalpy；

(2) thermodynamic computing of cooling tower, simultaneous cooling tower filler characteristic quantity equation Ω are calculated using enthalpy potential method_n'=B λ^kAnd cooling Tower cooler number equationWork as Ω_n'=Ω_nWhen, solve to obtain the air water of cooling tower under actual environment operating mode Than λ, wherein B, k is the experimental constant of packing；K is evaporated water coefficient of bringing off heat, and dt is that infinitesimal filler is intake with going out The water temperature difference of water, C_wFor the specific heat of water, t₁To enter tower water temperature, t₂For outlet water temperature；Approached in calculating process using linear iteraction Method, until error is in allowed band, finally obtain t₁* the gas-water ratio of corresponding equalization point, the method can be forced quickly Closely try to achieve final solution；

(3) under actual environment operating mode cooling tower required minimum fan delivery G_k=λ_k·Q·ρ_w/(ρ_k10000), wherein G_kFor Ventilation under kth kind environmental working condition, ρ_kFor the atmospheric density under kth kind environmental working condition, ρ_WFor the density of recirculated water, λ_kFor kth Enter the air of filler and the mass ratio of water under kind environmental working condition.

5. cooling tower according to claim 1 half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, Characterized in that, cooling tower described in step D half adjusts the frequency conversion of blower fan whole year different leaves established angle kind number frequency conversion per hour It is as follows to become angle and optimizing operating scheme calculating determination process：

(1) whole year, the maximum of minimum ventilation rate needed for all moment cooling towers was used as this using in one week using week as chronomere Week needs ventilation, sets this week fan blade established angle β_tw, rated speed air quantity G_twAnd fan efficiency η_ftw, to any small When, the required ventilation of this hour of cooling tower is used as using the maximum of minimum ventilation rate needed for this hour all moment cooling towers G_th, it is desirable to G_tw≥G_th, by frequency conversion per hour, fan operation air quantity is equal to cooling tower required ventilation per hour, weekly often Hour conversion efficiency beWherein η_bpthFor t_hHour fan frequency converter effect Rate, G_thFor blower fan t_wMonday day t_hThe ventilation of hour, G_twFor blower fan t_wUnder week setting blade angle rated speed Air quantity, A, B, C are constant；

(2) motor efficiency is under arbitrary loadT_wOne day energy consumption of all blower fan systems isWherein A_twFor blower fan system t_wThe energy consumption of all some days, ρ_thFor t_hThe sky of hour Air tightness, P_thFor t_hThe fan operation blast of hour, η_ftwFor t_wAll fan operation efficiency, η_emthFor t_hHour blower fan fortune Row auxiliary motor efficiency；

(3) t is set_wThe changing rule of ventilation by the hour is identical needed for all cooling towers every day, then the annual operation of blower fan of cooling tower Energy consumption isAnnual energy expenditure is Y_z=A_zY, wherein A_zFor cooling The annual operation power consumption of tower blower fan, t_wCycle is run for whole year, T runs all numbers, Y to be annual_zUsed for annual total energy source cost, y represents electricity Take unit price；

(4) calculate and determine under annual actual environment operating mode that cooling tower institute required airflow changes with time rule, with equation G_r=G_r (t_w) represent；The annual operation blade angle kind number of blower fan is set, implements converting operation per hour, lists the annual operation consumption of blower fan The calculating formula of electricity, meeting fan operation air quantity G_th≥G_rOn the premise of, it is with the minimum target of operation energy consumption, blower fan is annual The time point of angle as variable, is calculated by Optimized Iterative, obtains the fan operation consumption of the annual blade angle number of blower fan Electricity A_zMinimum value and its corresponding optimal blade angle and its angle time point；Change blower fan whole year blade angle number weight New optimization calculates, and the fan frequency conversion change angle and optimizing operating scheme for obtaining annual required various blade angle numbers is as follows：

Scheme one：Annual a kind of blade angle frequency conversion per hour daily optimization operation

Cooling tower needs ventilation to meet with the different and different of each time environment in blower fan rated speed air quantity annual in 1 year Cooling tower maximum demand ventilation G_maxOn the premise of, a kind of blade angle β of the annual operation of setting blower fan₁, rated speed wind Engine efficiency is η_f1, air quantity G₁, G can be met₁≥G_rRequirement, blower fan variable-frequency and variable-speed per hour daily under this blade angle Operation, frequency conversion rear fan air quantity need ventilation equal to cooling tower each hour, then annual fan operation total energy consumption isBy fan efficiency and blade angle relation Substitute into, with the annual minimum target of fan operation total energy consumption, program calculation, solve and determine annual optimal rated speed operation wind Amount, corresponding blade angle, make operation total cost minimum；

Scheme two：Annual 2 kinds of blade angles frequency conversion per hour daily optimization operation

This programme blower fan selects annual 2 kinds of blade angles converting operation per hour, ensures the logical of annual least favorable environmental working condition Air quantity, the optimal blade angle of the annual 2 kinds of blade angles operation of setting blower fan is respectively β₁、β₂, blower fan rated speed air quantity Respectively G₁、G₂If β₁≥β₂, G₁≥G₂, fan efficiency is respectively η_f1、η_f2, it was divided into three sections by annual T weeks：In the 1st Zhou Zhi t_{2 is small}Week and t_{2 is big}Zhou Zhi T week, fan blade established angle is turned down to β₂, air quantity G₂G can be met₂≥G_rRequirement, this two when Between section blower fan with rated speed air quantity G₂Start variable-frequency and variable-speed per hour to run；In t_{2 is small}+ 1 is all to t_{2 is big}In -1 week, tune up wind Machine blade angle is to β₁, air quantity G₁G can be met₂≤G_r≤G₁Requirement, the period blower fan is with rated speed G₁Start every Hour variable-frequency and variable-speed operation.The blade angle that blower fan is run weekly is determined, variable-frequency and variable-speed per hour is implemented daily to blower fan Operation, annual fan operation total energy consumption are

With the minimum target of the annual total operation energy consumption of blower fan, with fan blade angle time separation rated speed air quantity G₁、G₂For Variable, to different air quantity G₁、G₂Value, program calculation, solve the minimum G of energy consumption₁、G₂Value, draw corresponding blade angle β₁、 β₂And angle time point t_{2 is small}、t_{2 is big}, obtain the fan frequency conversion change angle and optimizing operating scheme of annual 2 kinds of blade angles；

Scheme three：Annual 3 kinds of blade angles frequency conversion per hour daily optimization operation

This programme considers 3 kinds of blade angle β of whole year₁、β₂、β₃Operation, the efficiency eta of blower fan rated speed is corresponded to respectively_f1、η_f2、 η_f3, air quantity G₁、G₂、G₃If β₁≥β₂≥β₃, G₁≥G₂≥G₃；It was divided into five sections by annual T weeks：1st week to t_{3 is small}Week and t_{3 is big} Zhou Zhi T week, blower fan is with blade angle β₃Operation, the air quantity G of corresponding rated speed₃G can be met₃≥G_rRequirement, the time Duan Fengji is from air quantity G₃Start converting operation per hour；T_{3 is small}+ 1 is all to t_{2 is small}Week and t_{2 is big}Zhou Zhi t_{3 is big}- 1 week, blower fan with Blade angle β₂Operation, the air quantity G of corresponding rated speed₂G can be met₃≤G_r≤G₂Requirement, the period blower fan is from air quantity G₂Start converting operation per hour；T_{2 is small}+ 1 is all to t_{2 is big}In -1 week, blower fan is with blade angle β₁Operation, corresponding rated speed Air quantity G₁G can be met₂≤G_r≤G₁Requirement, the period blower fan is from air quantity G₁Start converting operation per hour；Wind is determined The blade angle that machine is run weekly, implementation carry out fan frequency conversion per hour daily.Annual fan operation total energy consumption is

With the minimum target of the annual total operation energy consumption of blower fan, with fan blade angle time separation rated speed air quantity G₁、G₂、 G₃For variable, to different air quantity G₁、G₂、G₃Value, program calculation, choose the minimum G of energy consumption₁、G₂、G₃Value, draws corresponding leaf Piece established angle β₁、β₂、β₃And angle time point t_{3 is small}、t_{2 is small}、t_{2 is big}、t_{3 is big}, obtain the fan frequency conversion angle of annual 3 kinds of blade angles Optimize operating scheme；

Scheme four：Annual 4 kinds of blade angles frequency conversion per hour daily optimization operation

This programme, by scheme two and the method for scheme three, lists the annual fortune of blower fan using annual 4 kinds of fan blade established angles operation Row total energy consumption calculating formula, with the annual operation minimum target of total energy consumption of blower fan, program calculation solves, and determines optimal fan blade Established angle β₁、β₂、β₃、β₄, corresponding rated speed air quantity G₁、G₂、G₃、G₄And corresponding angle time point；

It can be solved with same method and determine that the blower fan of cooling tower frequency conversion of annual 5 kinds, 6 kinds ... blade angles becomes angle and optimizing and transported Row scheme.

6. cooling tower according to claim 5 half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, It is characterized in that：Step is calculated described in (4) by Optimized Iterative, and the blower fan that blade angle kind number is set to annual blower fan is transported Row power consumption A_zMinimum value and its corresponding optimal blade angle and its solution procedure at angle time point are as follows：

Programming carries out Optimized Iterative calculating, first inputs air quantity, blast, the work(of blower fan of cooling tower rated speed angle acceptable operating point Rate and efficiency, then institute's required airflow and corresponding atmospheric density input per hour by each week of cooling tower under annual varying environment operating mode, By taking annual 2 kinds of fan blade established angles operation as an example, since the adjustable minimum blade established angle of blower fan try generation, set 0.1 ° Angle step, the maximum of minimum ventilation rate needed for all moment cooling towers in one week is taken to need to divulge information as this week cooling tower Amount, compare 2 kinds of blade angles in examination generation corresponding to air quantity whether meet the ventilations of each all needs, if satisfied, then this week exists Run under such a fan blade established angle, if not satisfied, then being run under another fan blade established angle, it is determined that annual every After Zhou Yunhang fan blade established angle, by frequency conversion per hour, fan operation air quantity is set to be equal to this hour needs of cooling tower Ventilation；

The daily variable-frequency and variable-speed per hour of blower fan, although speed change rear fan energy consumption reduces, due to adding frequency converter energy consumption after frequency conversion, So the forward and backward frequency converter input power size of frequency conversion need to be compared, if frequency converter input power increases after variable-frequency and variable-speed, illustrate wind For the underpower that machine reduces to compensate the increased power of frequency converter, the hour just should not variable-frequency and variable-speed operation；

Annual fan operation energy consumption and energy expenditure are calculated with the method operation；Tried again by step length for fan blade again Established angle, annual fan operation energy consumption and energy expenditure are recalculated in aforementioned manners, all blade angles of blower fan are complete After portion's examination generation terminates, compare the scheme of annual the fan operation energy consumption and energy expenditure that draw minimum, and obtain 2 kinds of blades of blowing machine The optimal blade angle of established angle operation and angle time point.

7. cooling tower according to claim 1 half adjusts the determination method that blower fan whole year frequency conversion becomes angle and optimizing operating scheme, It is characterized in that：Cooling tower described in step E half adjusts the change of blower fan whole year different leaves established angle kind number variable-frequency and variable-speed per hour The angle and optimizing operating scheme expense that frequency becomes compares as follows with annual optimal frequency conversion angle operating scheme determination process：

Blower fan of cooling tower whole year different leaves established angle kind number per hour variable-frequency and variable-speed frequency conversion become angle and optimizing operating scheme expense, Including operation energy consumption expense, angle modulation expense, compared with not frequency conversion, frequency converter original equipment expense is added.According to operating scheme Angle number accumulation calculating angle modulation expense.Finally, to common to scheme four including original operating scheme, improvement project and scheme one The annual energy of 6 kinds of schemes, angle modulation and set up equipment and share total cost and be compared, with total cost at least for principle, it is final really Determine cooling tower half and adjust the annual optimal frequency conversion angle operating scheme of blower fan.