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Abstract

Content

Introduction

With the rising cost of electricity increasingly have to think about saving the financial savings. In a greater degree this applies to educational institutions and various companies because the cost of electricity for businesses much more expensive than in apartments or private homes.

There are many different ways, methods and measures for energy savings. The main and necessary activities are replacing incandescent light bulbs by more economical compact luminescent lamps(CLL), replacement of out of date control apparatus on more economical. Other than that undeniable method is the inclusion of light in the time required for this, and also off when not needed. In this time on sale there were LED light lamps that help you save even more money than CLL or luminescent lamps(LL) type of T5 and T8, unfortunately, the cost is too high and the light is a perspective view of the future. The next source of energy efficiency is the introduction of different sensors lighting and occupancy sensors. Is also quite an effective energy saving device may be considered intellectual relays, allowing for a realization planned actions that will be carried out without human intervention for quite a long time.

So as a practical energy saving in our country is going through a period bustle, the purpose of the master's work is the analysis and evaluation of existing measures to reduce losses in electrical networks of Donetsk National Technical University

1. Actuality of energy-savings

Actuality of energy saving and energy efficiency in recent years is so obvious that this issue is being discussed as across government, as well in many companies. For most businesses, the issue of energy efficiency, especially in the context of continuous increase in the cost of energy resources is becoming not only a question of competitive advantage, but also often a question of survival of the enterprise. Considerable part of expenses of electricity has for lighting .

However, the technical part of the majority of enterprises producing electric power is characterized by outdated and equipment wear. The degree of wear of equipment in the electricity of the country is more than 50%. So the question the introduction of energy-saving technologies is extremely relevant and introduction of these technologies can act as a source of additional funds for power-to-energy industry.

2. Overview of energy conservation in educational buildings Donetsk National Technical University

All measures can be classified into two groups: energy saving lighting in buildings and energy saving in the supply networks with electrical equipment.

Energy saving lighting in buildings:

  1. Reduction of applications incandescent lamps and replacing them with compact luminescent lamps;
  2. Replacement of electromagnetic ballasts in luminescent lamps for electronic;
  3. Replacing the incandescent lamps,compact luminescent lamps and luminescent lamps to LED lamps;
  4. The use of modern reflectors;
  5. Colouring premises in lighter colors;
  6. The use of energy-saving lamps on the of semiconductor light sources.

Energy savings in the supply networks and electrical equipment:

  1. Installation of automatic controlled condenser batteries;
  2. Replacement of transformers at the substation for more powerful and switching one of them in "cold reserve";
  3. Replacement of old equipment in laboratories and installation in their place a more economical;
  4. Equipping modern energy metering devices.

As part of the master's work is planned considered in greater detail in energy saving lighting and energy saving networks of educational institutions, to get economic based on the results of expediency of using these energy saving measures.

3. Energy saving lighting in premises

Careful with the greatest economicthe effect of consumption of electricity for lighting is oneimportant task of power. Saving energy on lightingshould not come at the expense of standards illumination offof light or non-useartificial lighting in low level of natural light,because reduced illuminationleads to a decrease in visual capacity, poorpsychophysiological state of the people, improve injuries, reduceproductivity and product quality. Losses from thelighting conditions are far superior cost savingselectricity. In this connection it is advisable to use a energy-efficient light sources that in the past decadewidespread.

3.1 The economic effect of replacing incandescent light bulbs with compact luminescent lamps

The emergence and rapidthe recent development of compact fluorescentlamps (CFLs), which have 8-10 times longer duration of combustion and 5times more light output than incandescent bulbs (IL)show the need for a significant expansion of the use of these lampsin the most important areas - the residential sector, as well as in commercial andpublic and administrative buildings. CFL small size havingbuilt-in compact lamp ballasts andstandard screw base[1] , can directly replace existing IL lamps ranging from 25 to 100 watts. The use of such CFLs canbe most effective in those kinds of lighting installations(DU), where today the most abundant source of light is the IL.Comparative characteristics of CFLs and IL are shown in the table 1[2].

Table 1 – Comparative characteristics of CFLs and IL

Incandescent lamp CFL The ratio of light output of CFLs to the light output IL, rel. u
Power, W Luminous, lm Power, W Luminous, lm
25 200 5 200 4,3
40 420 7 400 5,3
60 710 11 600 4,5
75 940 15 900 4,7
100 1360 20 1200 4,3
2 х 60 1460 23 1500 5,4

According to available information about the lighting equipment in the educational building was calculated the cost of upgrading lighting systemsby substituting IL to CFLs, and was produced economic evaluation of the event. In the calculations were made the following assumptions:

  1. The current tariff Electricity 1 UAH. / kW∙h
  2. Lamps operated in 1250 hours per year.
  3. The cost of the luminaire with IL 100W - 2.5 UAH.
  4. The cost of a compact fluorescent lamp20 W - 30 UAH.
  5. Accept that CFLs work3000 hours as developments after this time CFL lose ≈ 50%luminous flux and must be replaced.

Table 2– Economic evaluation of replacement to CFLs with LNthe same type of cap

Light IL(installed) CFL
1. Lighting System (OS):
Life time, h: 1000 3000
The number of fixtures, pieces. 356 356
The cost of fixtures installed
Number of Lamps. 356 356
The cost of light, UAH 890 10680
The cost of the control system, UAH - 0
Installation costs (Rs. / Lamp), UAH - 0
The total cost of the installation, UAH 890 10680
2. Shelter Service:
The number of lamps replaced after 3,000 hours of work pieces. 1068 0
The cost of replacing lamps, UAH 0 0
The cost of replacement bulbs (the failed), UAH 2670 0
Total cost of service, UAH 2670 0
3. Power consumption OS:
The power consumed by the OS, kW 35,6 7,12
Electricity consumed by the OS for 3000 h, kW∙h 106800 21360
Total expenditure on electricity, UAH 106800 21360
4. The total cost of the use of DU: 110360 32040
Savings in energy costs, % 0 71
Annual operating costs UAH 45983,3 13350
Annual savings, UAH / Year - 32633,3
Payback, years - 0,41
5. The results of the modernization of the OS:
Annual electricity consumption, kW∙h 44500 8900
The annual reduction in energy consumption, kW∙h - 35600

In this, the annual decline electricity consumption in the university building will be 35600 kW – it's 71% savings. This event will pay off 5 months.

3.2 Modernization of the lighting system by replacing electromagnetic ballasts to electronic

Many businesses still using fluorescent lamp T5 and T8, so the replacement of electromagnetic ballasts to electronic conventional demand not less than the replacement of incandescent lamps to CFLs.

All discharge lamps arefalling current-voltage characteristics and the ignition voltage of these lamps,generally higher voltage. Therefore, incorporating all HID lamps (except the "integrated" CFLs) requires special equipment providing the starting and run a current through the lamp (ballast).

Now comes prettya wide range of compact fluorescent lamps, whichapparatus incorporating combined with the overall design of the lamp, sothe use of individual units is not required. In all other casesneed separate ballasts, stabilizing the discharge current,and ignition apparatus for the discharge[3].

Gear generally comprises threecomponent: ignitor, stabilizer lamp current anddevice that provides a source of electromagnetic compatibilitylight and electric network.

stabilizationcurrent discharge lamps of all types is provided by the inclusion ofseries with the lamp current limiting elements. Incurrent-limiting elements will inevitably lose some power, nogenerating efficiency. Therefore, such elements areempty, unnecessary load - ballast.

In principle, as ballastYou can use any resistive, inductive or capacitiveresistance. But in practice applicable only inductive and onlyspecial mercury-tungsten lamps - in the form of active threadsintensity. As an inductive resistances are always usedspecial electromagnetic devices called inductors orelectromagnetic ballasts.

Recent years have seen a verywidespread inclusion of electronic devices and fluorescentlow-power metal halide and sodium lamps. In such apparatusescombined all three functions - ignition current regulation andelectromagnetic compatibility.

To ensure theElectromagnetic compatibility of lamps with an electric network in mostcases used a capacitor comprising mostly right onnetworkingstress parallel to the luminaire.

Ballast in the ballast forfluorescent lamps - or a combination of inductors and chokescapacitors.

In the best chokes for lamps36 W lost about 6 watts (approximately 15% of the lamp power) havethin tubes (4-11 W) power losses in the inductor may be equal topower lamps themselves. Therefore, the luminous efficiency lamps in realluminaires are always lower than that specified in the documentation. InTable 3 shows the power losses in the inductor[4].

Table 3 – The power lossin chokes

Class balasts Power loss, W
With the lamp 18 W With lamp 36W With lamp 58W
D 12 10 14
С 10 9 12
В2 8 7 9
В1 6 6 8

Chokes create anotherembarrassing moment - the phase shift between current and voltage.Electricity supply in a sinusoidal pattern. If the lampsfilament current is always in phase with the voltage and accuratelyrepeats its shape, in any inductor current lags the voltagea fraction of the period which is measured in degrees. If the fullperiod is equal to 360 °, the "pure" chokecauses behind the current on the voltage level at the quarter-cycle or90 °. In conjunction with this lamp "shiftphase "is always less than 90 °and dependson the quality of the throttle.

On Inductor labels allcountries do not specify the angle by which the current lags the voltage atinclusion of the throttle corresponding lamp power, and the cosine of theangle - cosφ, also called power factor.

many of the shortcomingsfluorescent lamps and chokes eliminated by usingElectronic high-frequency switching devices (ECG).

Figure 1 shows theblock diagram of electronic ballasts, which contains all the basic units: input filterhigh frequency 1, rectifier 2, HA formsconsumption from the mains power supply 3, the control stage 4, the power amplifier5, the output stage 6.

Cтруктурная схема ЭПРА

Drawing 1 -The block diagram of an electronic device inclusion
(Animation: 7 frames, 31 kilobytes)

To suppress high frequency interference from electronic ballast power supply, use U-shapedor double U-shaped filter inductance of a few mHcapacities up to 1000 nF. Typically, additionally for the same purposeswitched the order of several nF capacitance between one of the feedconductors (usually neutral) and ground wire. asrectifier can be any standard bridge,calculated on the respective currents and voltages.

Correction of consumptioncurrent by means of powerful transistors managed by special devices. This developed and commercially produced integrated circuits that monitor current form.

Really in electronic devicesswitching the frequency of the output voltage of the power amplifier 5 is close toChains of resonant inductor and capacitor.So when the machine through the electrodes lamp current flowssufficient for heating them to the desired temperature, andcapacitor voltage is created, necessary for the emergence ofdischarge lamp with warm electrodes. After lighting the lampvoltage falls to its burning voltage and frequency of the voltageconverter automatically adjusts to a lampleaking current setpoint.

In most modernapparatus control unit 4 also performs two functions: the stabilization lamp current at line voltage fluctuation and correction factor capacity. To the best of modern devices power factor closeto 1 (0.95 - 0.99).

Options shape correctioncurrent consumption ("the suppression of the higher harmonics")usually performs input filter 1. Suppression of harmonics andcorrection of current consumption provide electromagneticthe compatibility of the device with a power line.

Some of the phones unitControl 4 has another function - to provideDimming lights, mostly due to the changevoltage frequency converter.

The principal differenceelectronic circuits incorporating fluorescent lamps from starter-throttleis such that the lamp circuit current fed highfrequency, typically 20-40 kHz instead of 50 Hz.

RF power lampsprovides the following benefits:

  1. Due to the naturehigh-frequency discharge lamps increases light output. thisincrease the greater the shorter the lamp: lamps with 36Wlight output increases by about 10%, at 18 watt bulbs- 15%;
  2. The depth of the light pulsesflow rate of 100 Hz is reduced to approximately 5%;
  3. Excluded sound interferenceproduced by reactors;
  4. Eliminates the flashing lights atturn on;
  5. Eliminates the needpower factor correction (correction cosφ);
  6. By eliminating flasheswhen the warm-up and accurate electrodes increases lamp life(up to six times);
  7. Now you canDimming lights;
  8. Electronic devicesmuch easier than correction capacitors and inductors.

Thus, ballasts eliminatemost of the problems with the LL starter circuits, these inclusions.However, these devices have a disadvantage that prevents themwidespread introduction: the price of electronic devices is higher thanchokes, starters and compensation capacitors combined. TopicsStill, in the European Union share lamps with electronicdevices is close to 50% of all light fixtures with LL. necessaryNote that a new generation of fluorescent lamp flasks diameter16 mm can work essentially only with the electronic apparatus.This fact provides additional benefits to the fixturessuch gear.

In addition to providingmost comfortable lighting ballasts allow you to create and systemsautomatic light control, giving savingsup to 75%[5] .

Table 4– Changing the light output of the lamp + ballast kit withdifferent types of gear

power lamp,W The standard electromagnetic ballasts Electronic control gear (ECG)
The total capacity of the set, W The light flux,  lm The light output from the set The total capacity of the set, W The light flux,  lm The light output from the set
lm/W % lm/W %
18 29 1450 50,0 100 19 1350 71,0 142
2 х 18 23 1450 63,0 100 18 1400 77,7 123
36 46 3450 75,0 100 36 3350 93,0 124
58 71 5400 76,0 100 55 5200 94,5 124

On the basis of availableinformation aboutlighting equipment we calculated the cost of upgradingthe lighting system by replacing electromagnetic ballasts to electronic ininvestigated the educational building, and was produced economic assessmentthis activity (see table 5)[6].

For the product of calculations wereadoption of such assumptions:

  1. The current tariff electricity 1 UAH. / kW∙h
  2. Lamps operated in 1250 hours per year.
  3. The cost of the lamp with the 1st lamp (EBFL 1h36 COMTECH) - 45 UAH.
  4. The cost of the luminaire with 2 lamps (ECG EBFL 2h36 COMTECH) - 80 UAH.

Table 5 - Economicassessment of the replacement of electromagnetic ballasts forelectronic

Lamps with LL
1-tube 2-tube
Number of units. 335 164
Power, W 36 72
The loss factor in EM 1,25
Electricity consumption in lighting EM, kW∙h/year 18844 18450
Loss factor electronic ballast 1,05
Electricity consumption in lamps with electronic ballasts, kW∙h/year 15828 15498
Reducing energy consumption lamps with LL kW∙h/year 3016 2952
Annual energy savings, kW ∙ h 5968
The cost of energy savings, UAH 5968
The cost of electronic ballasts, UAH 45 80
Costs for the purchase of electronic ballasts, UAH 28195
The cost of replacing ballasts, UAH 0
Payback year 4,7
Total costs for the event as a whole, v 28195

This annual reduction of energy consumption in education building will be 5968 kW. The event will be repaid over 4.7 years.

3.3 Energy-saving lamps in the semiconductor light sources

LEDs are semiconductor devices that convertan electric current directly to the emission of lightThey are characterized by low power consumption, and hence,have good potential for energy saving.

Until now, one of thesignificant barriers to mass adoption of LEDs inillumination was the high cost compared with conventionallight sources, so they are used mainly indecorative lighting of buildings and lighted advertising signs. However, a gradual reduction in price and increase the technical characteristics LED products, as well as the urgent need to reduceenergy consumption, allow today to apply these energy-saving technology [7] .

Consider the basic differences new - LED lighting technology from the lamp:

  1. LED Downlightprovides illumination with a higher contrast, thereby improving quality of illumination of the object;
  2. Environmentally friendly and non-require special maintenance and disposal;
  3. Their service life considerably than existing equivalents (period of the lamp at least 30thousands of hours);
  4. Adjustment lighting supply reduction voltage;
  5. The absence of pulsationsflux.

Taking the data on the number of LN ineducational case of clause 3.1, we carry out economic calculation and evaluationfeasibility of using LED lights instead of LN, the calculation ofare summarized in Table 6 [8] .

Table 6 - Economic assessment of LN replacement for LEDlamps with the same typecap

Источник света LN(installed) LED Bulbs
1. Lighting System (OS):
Life time, h: 1000 25000-40000
he number of fixtures, pieces. 356 356
The cost of fixtures, UAH Установлены
Number of Lamps. 356 356
The cost of light, UAH 890 15138
The cost of the control system, UAH - 0
Installation costs, UAH - 0
The total cost of the installation, UAH 890 10680
2. Shelter Service:
The number of lamps replaced after 3,000 hours of work pieces. 1068 0
The cost of replacing lamps, UAH 0 0
The cost of replacement bulbs (the failed), UAH 2670 0
Total cost of service, UAH 2670 0
3. Power consumption OS:
The power consumed by the OS, kW 35,6 2,67
Electricity consumed by the OS for 3000 h, kW∙h 106800 8010
Total expenditure on electricity, UAH 106800 8010
4. The total cost of the use of DU:. 110360 23148
Savings in energy costs, % 0 79
Annual operating costs UAH 45983,3 4094,4
Annual savings, UAH/Year - 41888,6
Payback, years - 0,37
5. The results of the modernization of the OS:
Annual electricity consumption, kW∙h 44500 3337,5
The annual reduction in energy consumption, kW∙h - 41162,5

From the calculations show that the annual reduction in energy consumptionamount to 41162 kW - that's 79% savings. The eventwill pay for itself in about 5 months.However, although return on CFLs and LED bulbs are almost identical, but the lifespan of the LED lamps≈ 10times.

This master's work is not completed yet. Final completion: December 2013. The full text of the work and materials on the topic can be obtained from the author or his head after this date.

References

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