CN102003736B

CN102003736B - Heating load stage quality regulation method

Info

Publication number: CN102003736B
Application number: CN2010106003062A
Authority: CN
Inventors: 姜永成; 方修睦; 郑瑞芸; 吴洁清
Original assignee: Harbin Institute of Technology Shenzhen
Current assignee: Harbin Institute of Technology Shenzhen
Priority date: 2010-12-22
Filing date: 2010-12-22
Publication date: 2012-11-21
Anticipated expiration: 2030-12-22
Also published as: CN102003736A

Abstract

The invention discloses a stage-by-stage quality adjustment method for heating load, which relates to an adjustment method for a hot water heating system, and belongs to the technical field of heat supply adjustment. The purpose of the present invention is to solve the technical problems of high energy consumption in transmission in the traditional quality adjustment method of the heating network and the imbalance of the heating network that is prone to occur in the traditional quantity adjustment, and to provide a heating load distribution system that meets the adjustment requirements of users and has low energy consumption. Phase quality adjustment method. Main steps: calculate the outdoor critical temperature, and divide the heating into three adjustment stages: gradually increase the water supply temperature according to the heating load, and maintain the minimum operating flow; Change the system operating flow; as the heating load gradually decreases, when the outdoor temperature is higher than the outdoor critical temperature, it enters the end of the heating period, the system flow is reduced to the minimum operating flow, and the system operation mode changes to qualitative adjustment again until the heating period Finish. The energy-saving effect of the method of the invention is remarkable.

Description

Heating demand is the quality adjustment method stage by stage

Technical field

The present invention relates to a kind of control method of hot-water heating system, the heating Regulation technical field.

Background technology

At present, traditional heating Regulation technology mainly contains:

(1) matter is regulated.When carrying out the matter adjusting, only change the supply water temperature of heating system, and user's quantity of circulating water remains unchanged.The water circulating pump conveying energy consumption is high simultaneously, is unfavorable for energy-conservation.

(2) amount is regulated.When the amount of carrying out is regulated, only change the networking flow of heating system, and supply water temperature remains unchanged.In utilization during this control method, when flow is reduced to certain value at the networking, the flow regime of water will depart from region of quadratic resistance law the assignment of traffic ratio is changed in the pipeline, and hydraulic misadjustment appears in heat supply network, and coefficient of frictional resistance increases, and be unfavorable for energy-conservation.

(3) matter that changes flow is stage by stage regulated.This control method just is divided into several stages by outdoor temperature, and in each stage, the quantity of circulating water of system remains unchanged, and regulates by the matter that changes the networking supply water temperature and carries out heating Regulation.Though this control method is regulated than traditional matter and improved to some extent, water pump can only move under the constant frequency of segmentation, and the bigger energy saving space is still arranged.

Summary of the invention

The objective of the invention is in order to solve in the heat supply network tradition matter control method conveying energy consumption highly, conventional amounts is regulated the technical problems such as heat supply network imbalance that occur easily, provides a kind of user of satisfying to regulate requirement, and the lower heating demand of energy consumption quality adjustment method stage by stage." quality adjustment " according to the invention is meant " matter adjusting " and " amount is regulated ".

The present invention solves the problems of the technologies described above the technical scheme of taking to be:

The heating demand of the present invention detailed process of quality adjustment method stage by stage is:

Step 1, calculate outdoor critical-temperature t _W0, heat supply is divided into three adjusting stages:

According to outdoor critical-temperature t _W0The whole heating period of heating system varied in size according to heating demand be divided into three adjusting stages: initial stage, mid-term and latter stage; Wherein the outdoor temperature in initial stage and latter stage is greater than outdoor critical-temperature t _W0, and the outdoor temperature in mid-term is less than outdoor critical-temperature t _W0

Utilize formula (1), make supply water temperature equal to design supply water temperature, i.e. t _g=t ' _g, in the formula Then can calculate unique unknown quantity

Compare formula according to relative load again

Calculate the corresponding outdoor temperature t of this load _w, be the critical-temperature t of system _W0

t_{g} = t_{n} + {Δt}_{s}^{'} {\overset{&OverBar;}{Q}}^{1 / (b + 1)} + 0.5 {Δt}_{j}^{'} \frac{\overset{&OverBar;}{Q}}{G} - - - (1)

t_{h} = t_{n} + {Δt}_{s}^{'} {\overset{&OverBar;}{Q}}^{1 / (b + 1)} - 0.5 {Δt}_{j}^{'} \frac{\overset{&OverBar;}{Q}}{G} - - - (2)

Δ t ' in the formula _s=0.5 (t ' _g+ t ' _h-2t _n)--------the design average computation temperature difference of-----user heat exchanger

Δ t ' _j=t ' _g-t ' _h------------user's design supply backwater temperature difference

\overset{&OverBar;}{Q} = \frac{t_{n} - t_{w}}{t_{n} - t_{w}^{'}}

---------------relatively hot duty ratio, expression actual motion load and the ratio that designs load;

\overset{&OverBar;}{G} = \frac{G_{Min}}{G^{'}}

--------the ratio of-----minimum discharge and design discharge; G representes the heat supply network circular flow, and unit is t/h;

Band in the formula (1), (2) ' all be illustrated in the parameter under the design condition, not with ' be illustrated in the parameter under the service condition; t _gExpression heat supply network supply water temperature, unit are ℃; t _hExpression heat supply network return water temperature, unit are ℃; t _nExpression indoor design temperature, unit is ℃; B representes the coefficient in the radiator heat transfer formula, gets 0.3 usually;

Step 2, confirm the minimum operation of heating system flow according to design discharge, overall drag number:

Minimum according to the design discharge and the actual overall drag number of heating system are confirmed heating system is moved flow G _Min, this value is about rated designs flow G _Max40%, i.e. G _Min=G _Max* 0.4;

Step 3, matter are regulated operation:

Regulate operation in heating initial stage heating system according to matter, the operation flow is set minimum operation flow G _Min, supply water temperature changes with outdoor temperature, supply water temperature t _g, return water temperature t _hRegulate shown in above-mentioned formula (1), (2);

Step 4, improve supply water temperature t gradually according to heating demand _g, keep minimum operation flow G _Min:

Step 5, judgement outdoor temperature t _wWhether be to be lower than outdoor critical-temperature t _W0, if then execution in step six, otherwise, be back to step 3;

Step 6, amount are regulated operation:

Along with the increase of heating demand, the supply water temperature that matter is regulated reaches the maximum supply water temperature t of system _Gmax, get into the mid-term of heating this moment, and the regulating measure that changes system is regulated for amount;

Step 7, maintenance supply water temperature are that design load is constant, move flow according to return water temperature change system:

Keep supply water temperature constant, promptly maximum supply water temperature t for system designs supply water temperature _GmaxChange flow system flow according to Flow-rate adjustment rule shown in formula (3), (4);

Return water temperature t _hRegulate rule shown in formula (3), (4) with flow system flow G:

t_{h} = {2 t}_{n} + (t_{g}^{'} + t_{h}^{'} - {2 t}_{n}) + {(\frac{t_{n} - t_{w}}{t_{n} - t_{w}^{'}})}^{1 / b + 1} - t_{g}^{'} - - - (3)

G = G^{'} (\frac{t_{g}^{'} - t_{h}^{'}}{t_{g} - t_{h}}) (\frac{t_{n} - t_{w}}{t_{n} - t_{w}^{'}}) - - - (4)

Step 8, judge whether outdoor temperature is to be higher than outdoor critical-temperature t _W0, if then execution in step three, otherwise, be back to step 6;

Along with heating demand reduces gradually, outdoor temperature is higher than outdoor critical-temperature t _W0The time, get into heat supply latter stage this moment, and flow system flow is reduced to minimum operation flow G _Min, system operation mode becomes matter again to be regulated, and gets into step 3 again, and heating latter stage, the regulating measure with the initial stage was identical, so circulated, and finished until heating period.

The invention has the beneficial effects as follows:

It is low that the inventive method has a conveying energy consumption, makes the stable advantage of heating network operation.The present invention regulates the conveying energy consumption that can reduce system significantly than traditional matter, illustrates below:

Carry the physical parameter of fluid constant when water pump, when the density similarity factor was also constant, the power of water pump consumption was directly proportional with the cube of rotating speed, promptly be directly proportional with the cube of flow, as shown in the formula:

\frac{p_{1}}{p_{2}} = {(\frac{n_{1}}{n_{2}})}^{3} = {(\frac{G_{1}}{G_{2}})}^{3} - - - (5)

P in the formula, n, G represent power, rotating speed and the flow of water circulating pump respectively.

(annotate: formula (5) is seen " engineering fluid mechanics Pumps & Fans " P268 of Chemical Industry Press)

Find out that by (5) formula the operation flow of minimizing system will reduce the conveying energy consumption of system significantly.

During the constant flow operation:

The water circulating pump choice of capacity is to confirm after adding certain surplus according to its peak load in conventional design; And when lectotype selection, be difficult to again choose and the on all four water pump of design parameter; Therefore the actual installation capacity of water pump is often bigger than normal, and the rated load of general circulating pump only accounts for 60%～80% of place capacity.

Water circulating pump is according to the operation of constant flow operating mode, and when promptly heating system adopted matter to regulate operation, the actual motion flow generally was about 40% of metered flow according to the minimum discharge operation of water pump.

During the operation of unsteady flow amount:

When matter adjusting operation supply water temperature rose to peak, system's amount of changing into was regulated operation, and flow can be regulated between minimum discharge and maximum stream flow, and minimum discharge generally is about 40%.Then the changes in flow rate scope of operation the circulating pump rated load 40%～80% between, the flow mean value that amount is regulated operation is 60% of water circulating pump rated load.

Energy saving calculation:

Power saving rate calculates according to the computing formula that the mandatory national standard of GB12497 " threephase asynchronous economical operation " is implemented in the supervision guide:

K_{i} = \frac{{ΔP}_{I}}{P_{L}} = \frac{P_{L} - P_{e} {(\frac{\overset{&OverBar;}{Q}}{Q_{N}})}^{3}}{P_{L}} = 1 - \frac{{(\frac{\overset{&OverBar;}{Q}}{Q_{N}})}^{3}}{0.45 + 0.55 {(\frac{\overset{&OverBar;}{Q}}{Q_{N}})}^{2}} - - - (6)

In the formula: K _iPower saving rate, Δ P _IEconomize on electricity power, P _LThe input power of pump motor under the rated load, P _eThe rated power of pump motor label,

Water pump year operation average discharge, Q _NWater pump year operation metered flow.

Then matter adjusting stage fractional energy savings is:

K_{iz} = = 1 - \frac{{(\frac{0.4 Q_{N}}{Q_{N}})}^{3}}{0.45 + 0.55 {(\frac{0.4 Q_{N}}{Q_{N}})}^{2}} = 0.8810

Amount adjusting stage fractional energy savings is:

K_{il} = = 1 - \frac{{(\frac{0.6 Q_{N}}{Q_{N}})}^{3}}{0.45 + 0.55 {(\frac{0.6 Q_{N}}{Q_{N}})}^{2}} = 0.6667

Quality adjustment synthesis energy saving rate is stage by stage:

K _zl＝K _iz×P ₁+K _il×P ₂(7)

P in the formula ₁For the time of adopting matter to regulate operation accounts for the percentage of whole heating period time,

P ₂The time of regulating operation for the employing amount accounts for the percentage of whole heating period time, P ₁+ P ₂=1

The expense of circulation pump of heat-supply network power consumption is very considerable in heating system, carries out energy saving calculation with the instance of certain Thermal Corp.The total area of heat-supply service in concentrated supply of heating in the city sub-district, northeast is 1,000 ten thousand m ², system is the constant flow operation, total operation flow of physical record is 15267m ³/ h.Move 4 water pumps, the lift of water pump is that 65m, flow are 3846m ³/ h, motor rated power are 800kW.Motor is selected the 10kV power voltage supply, and electricity price is according to 0.747 yuan/kWh of general industry electricity price, and heating time calculated according to 180 days, and the year electricity charge rough calculation that the constant flow operation needs is:

0.747 ten thousand yuan of * 4 * 800 * 180 * 24=1032.653

If adopt quality adjustment operation stage by stage; The matter adjusting stage calculates by 40% of design discharge, and amount is regulated the stage system average discharge and calculated by design discharge 60%, and the design supply and return water temperature is by 95/70 ℃ of consideration; Calculate outdoor critical-temperature and be about-14 ℃; Looking into " Heat Supply Engineering " relevant data can know, the amount adjusting stage is about 70 days, then P ₁=0.611, P ₂=0.389, the synthesis energy saving rate of quality adjustment is stage by stage:

K _zl＝K _iz×P ₁+K _il×P ₂＝0.8810×0.611+0.6667×0.389＝0.7976

The electricity charge of practicing thrift are:

1032.653 ten thousand yuan of * 0.7976=823.68

Obviously the energy-saving effect of the inventive method is very significant.

Description of drawings

Fig. 1 is the operational flow diagram of the method for the invention, Fig. 2 be the method for the invention the principle schematic of quality adjustment stage by stage (among the figure: the variation of reference axis 1 expression outdoor temperature, its positive direction representes that temperature is more and more lower; Reference axis 2 signal temperature, flow etc., its positive direction amount of expression is increasing; Curve 3 expression supply water temperature curves, curve 4 expression return water temperature curves, curve 5 expression heating system circular flow curves, 1-1 representes outdoor critical-temperature t _W0, 3-1 representes critical supply water temperature t _G0, 4-1 representes critical return water temperature t _H0, 5-1 representes the critical flow G of system ₀

The specific embodiment

The specific embodiment one: as illustrated in fig. 1 and 2, the described heating demand of this embodiment detailed process of quality adjustment method stage by stage is:

Utilize formula (1), make supply water temperature equal to design supply water temperature, i.e. t _g=t ' _g, in the formula (promptly

Be definite value), then can calculate unique unknown quantity

Compare formula according to relative load again

t_{g} = t_{n} + {Δt}_{s}^{'} {\overset{&OverBar;}{Q}}^{1 / (b + 1)} + 0.5 {Δt}_{j}^{'} \frac{\overset{&OverBar;}{Q}}{\overset{&OverBar;}{G}} - - - (1)

t_{h} = t_{n} + {Δt}_{s}^{'} {\overset{&OverBar;}{Q}}^{1 / (b + 1)} - 0.5 {Δt}_{j}^{'} \frac{\overset{&OverBar;}{Q}}{\overset{&OverBar;}{G}} - - - (2)

Δ t ' _j=t ' _g-t ' _h-------------user's design supply backwater temperature difference

\overset{&OverBar;}{Q} = \frac{t_{n} - t_{w}}{t_{n} - t_{w}^{'}}

-------------relatively hot duty ratio, expression actual motion load and the ratio that designs load;

\overset{&OverBar;}{G} = \frac{G_{Min}}{G^{'}}

Step 3, matter are regulated operation:

Step 6, amount are regulated operation:

t_{h} = {2 t}_{n} + (t_{g}^{'} + t_{h}^{'} - {2 t}_{n}) + {(\frac{t_{n} - t_{w}}{t_{n} - t_{w}^{'}})}^{1 / b + 1} - t_{g}^{'} - - - (3)

G = G^{'} (\frac{t_{g}^{'} - t_{h}^{'}}{t_{g} - t_{h}}) (\frac{t_{n} - t_{w}}{t_{n} - t_{w}^{'}}) - - - (4)

The present invention varies in size whole heating period and is divided into three periods according to heating demand: initial stage, mid-term and latter stage, wherein the outdoor temperature in initial stage and latter stage is greater than outdoor critical-temperature t _W0, in the early stage and latter stage, the constant maintenance of heat supply network circular flow is constant, supplies, return water temperature constantly increases; And the outdoor temperature in mid-term is less than t _W0, the heat supply network circular flow increases gradually, and it is constant that supply water temperature keeps, and return water temperature increases gradually.

Above content is to combine concrete preferred implementation to further specify what the present invention did, can not assert that practical implementation of the present invention is confined to these explanations.For the those of ordinary skill of technical field under this, under the prerequisite that does not break away from the present invention's design, can also make some simple deduction or replace, all should be regarded as belonging to the definite scope of patent protection of claims that the present invention submits to.

Claims

1. A step-by-step quality adjustment method for heating load, characterized in that: the specific process of the adjustment method is:

Step 1: Calculate the outdoor critical temperature t _w0 , and divide the heating into three adjustment stages:

According to the outdoor critical temperature t _w0 , the whole heating period of the heating system is divided into three adjustment stages according to the different heating loads: the initial stage, the middle stage and the final stage; the outdoor temperature in the early stage and the final stage is higher than the outdoor critical temperature t _w0 , and in the middle stage The outdoor temperature is less than the outdoor critical temperature t _w0 ;

Using formula (1), make the water supply temperature equal to the design water supply temperature, that is, t _g =t′ _g , where

Then the only unknown quantity can be calculated Then according to the relative heat load ratio formula

Calculate the outdoor temperature t _w corresponding to this load, which is the system outdoor critical temperature t _w0 ;

{t t}_{g g} = = {t t}_{n no} + + Δ Δ {t t}_{s the s}^{' '} {\overset{&OverBar; &OverBar;}{Q Q}}^{11 / / ((b b + + 11))} + + 0.5 0.5 Δ Δ {t t}_{j j}^{' '} \frac{\overset{&OverBar; &OverBar;}{Q Q}}{\overset{&OverBar; &OverBar;}{G G}} - - - - - - ((11))

{t t}_{h h} = = {t t}_{n no} + + Δ Δ {t t}_{s the s}^{' '} {\overset{&OverBar; &OverBar;}{Q Q}}^{11 / / ((b b + + 11))} - - 0.5 0.5 Δ Δ {t t}_{j j}^{' '} \frac{\overset{&OverBar; &OverBar;}{Q Q}}{\overset{&OverBar; &OverBar;}{G G}} - - - - - - ((22))

式中Δt′ _s ＝0.5(t′ _g +t′ _h -2t _n )-------------用户换热器的设计平均计算温差；

Δt′ _j ＝t′ _g -t′ _h -------------User's designed supply and return water temperature difference;

------------Relative thermal load ratio, indicating the ratio of actual operating load to design load;

-------------The ratio of the minimum operating flow to the design flow; G represents the circulation flow of the heating network, and the unit is t/h;

In the formulas (1) and (2), the ones with 'indicate the parameters under the design conditions, and the ones without 'indicate the parameters under the operating conditions; t _g indicates the water supply temperature of the heating network, in °C; t _h indicates the heating network Return water temperature, unit is ℃; t _n indicates indoor design temperature, unit is ℃; b indicates coefficient in radiator heat transfer formula, take 0.3;

Step 2. Determine the minimum operating flow of the heating system according to the design flow and comprehensive resistance:

Determine the minimum operating flow G _min of the heating system according to the design flow of the heating system and the actual comprehensive resistance, which is 40% of the rated design flow G _max , that is, G _min = G _max × 0.4;

Step 3, quality adjustment operation:

In the early stage of heating, the heating system operates according to the quality regulation, the operating flow is the predetermined minimum operating flow G _min , the supply water temperature changes with the outdoor temperature, the supply water temperature t _g and the return water temperature t _h are adjusted according to the above formula (1), ( 2) as shown;

Step 4. Gradually increase the water supply temperature t _g according to the heating load, and maintain the minimum operating flow rate G _min ;

Step 5. Determine whether the outdoor temperature t _w is lower than the outdoor critical temperature t _w0 , if yes, execute step 6, otherwise, return to step 3;

Step 6. Quantity adjustment operation:

With the increase of heating load, the quality-adjusted water supply temperature reaches the maximum water supply temperature t _gmax of the system. At this time, it enters the middle stage of heating, and the adjustment method of the system is changed to quantity adjustment;

Step 7. Keep the water supply temperature unchanged at the design value, and change the system operating flow according to the return water temperature:

Keep the water supply temperature constant as the system design water supply temperature, that is, the maximum water supply temperature t _gmax ; change the system flow according to the flow regulation rules shown in formulas (3) and (4);

The adjustment law of the return water temperature t _h and the circulation flow G of the system heating network is shown in formulas (3) and (4):

{t t}_{h h} = = 22 {t t}_{n no} + + (({t t}_{g g}^{' '} + + {t t}_{h h}^{' '} - - 22 {t t}_{n no})) + + {((\frac{{t t}_{n no} - - {t t}_{w w}}{{t t}_{n no} - - {t t}_{w w}^{' '}}))}^{11 / / b b + + 11} - - {t t}_{g g}^{' '} - - - - - - ((33))

G G = = {G G}^{' '} ((\frac{{t t}_{g g}^{' '} - - {t t}_{h h}^{' '}}{{t t}_{g g} - - {t t}_{h h}})) ((\frac{{t t}_{n no} - - {t t}_{w w}}{{t t}_{n no} - - {t t}_{w w}^{' '}})) - - - - - - ((44))

Step 8. Determine whether the outdoor temperature is higher than the critical outdoor temperature t _w0 , if yes, perform step 3, otherwise, return to step 6;

As the heating load gradually decreases, when the outdoor temperature is higher than the critical outdoor temperature t _w0 , it enters the end of the heating period, the system flow is reduced to the minimum operating flow G _min , the system operation mode changes to quality regulation again, and then enters step 3 , the adjustment method at the end of the heating period is the same as that at the initial stage, and so on until the end of the heating period.