Geri Dön

Pompalarda ve fanlarda değişken hızlı tahrik ile akış kontrolu ve enerji tasarrufu

Flow control on pumps and fans by using A.C. adjustable drives and energy savings

  1. Tez No: 22059
  2. Yazar: İSMAİL KARTAL
  3. Danışmanlar: PROF. DR. M. EMİN TACER
  4. Tez Türü: Yüksek Lisans
  5. Konular: Elektrik ve Elektronik Mühendisliği, Electrical and Electronics Engineering
  6. Anahtar Kelimeler: Belirtilmemiş.
  7. Yıl: 1992
  8. Dil: Türkçe
  9. Üniversite: İstanbul Teknik Üniversitesi
  10. Enstitü: Fen Bilimleri Enstitüsü
  11. Ana Bilim Dalı: Belirtilmemiş.
  12. Bilim Dalı: Belirtilmemiş.
  13. Sayfa Sayısı: 109

Özet

ÖZET Pompa, fan veya kompresör gibi santrifüj yükler veya akışkan tahrik sistemleri dünyada üretilen elektrik enerjisinin büyük bir bölümünü tüketmektedir. Bu sistemlerde eskiden beri tahrik motoru olarak sabit hızlı asenkron motorlar kullanılmaktadır. Bu durumda akışkan kontrolü vana damper gibi ek düzeneklerle sağlanmaktadır. Bu düzenekler sistemde ek kayıplara neden olarak büyük bir enerji harcanmasına neden olmaktadır. Son yıllarda bu konuda yapılan çalışmalar sonucun da tahrik motoru olarak değişken hızlı asenkron motor kullanılmasının daha faydalı olacağı anlaşılmıştır. Bu tür bir uygulamada hem akışkan kontrolü için ek bir düzeneğe ihtiyaç kalmaz hem de büyük miktarlarda enerji tasarrufu sağlanır. Bu çalışmada şimdiye kadar bu konuda yapılan çalışmalar açıklandıktan sonra, sistemin elemanlar ve kontrol açısından işlevleri önce açıklanmış, sonra da Ereğli Demir ve Çelik Fabrikalarında konu ile ilgili olarak yaptığım çalışmalar verilmiştir. Tezin birinci bölümünde konunun tanıtılması ve değişken hızlı tahrik sistemlerinin üstünlükleri açıklanmış tır. îkinci bölümde Asenkron makina kontrolünün prensipleri, asenkron makina kontrol yöntemlerinden olan skalar ve vektörel kontrolü açıklanmış ve ayrıca bu bölümde konuya yönelik düzenlenmiş bir sistem olan G.T.O-IMD sistemi hakkında bilgi verilmiştir. Üçüncü bölümde pompalar ve fanlar hakkında bilgi verildikten sonra, dördüncü bölümde devir hızı ayarı ile akışkan kontrolü ve diğer yöntemlerin karşılaştırılması yapılmıştır. Beşinci bölümde kullanılan enerjinin hesaplanması ve ekonomik değerlendirmesi yapılmış, ayrıca bu değerlendirme için bir hesap yöntemi verilmiştir. Bu hesap yönteminin uygulaması Erdemir'deki bazı sistemler için verilmiştir. Altıncı bölümde ise sonuçlar verilmiştir.

Özet (Çeviri)

SUMMARY FLOW CONTROL ON PUKP3 AND FANS BY USING A.C. ADJUSTABLE DRIVES AND ENERGY SAVINGS A procedure is offered for the evaluation of the energy savings obtained by the use of ac adjustable speed drives on pumps-fans and other types of driven equipment such as compressors or extruders and mixers. A method for the economic evaluation of the energy savings is also offered. The Advantages of Using AC Adjustable-Speed Drives The advantages gained by using ac adjustable-speed drives (here after referred to as ASD's or ac drives) on pumps, fans, compressors and other equipment have been widely publicized in recent years and their use in indus try has been on increase. Some of the primary advantages they offer may be summarized as follows. 1. Energy is saved in the proses as compared with constant speed drives which utilize throttling valve on pumps or in let guide vanes and damper on fans. 2. Where the proses requires adjustable speed ac drives are more efficient than adjustable-speed coupling and have maintenance advantages. 3. The soft starting characteristic softens the starting shock on motor, couplings, gears, and driven equipment. 4. Any number of restive restarts is allowed for checkout and balancing at start up time. 5. Rated speed in excess of 3 000 rpm are a possibi lity without using a gear since it is possible for ac in verters to operate a frequencies considerable in excess of 5 0 Hz. 6. The permissible range of flow control is gene rally higher with adjustable speed. Although the preceding list demostrates there are many reasons to apply ac drives other than just energy savings, normaly this is the primary justification for the use of ac adjustable speed drives. It is probably safe to say that in the majority of existing costant-speed drive applications in industry, some energy can be saved with the use of ac adjustable- - vx -speed drives. Since aç drives are a sophisticated and costly piece of eguipment, the degree of energy savings in a gi- ven application must be sufficiently large to justify a relatively large initial expenditure. Control of Induction Machines The control of aç machines is considerably more complex than that of de machines and this complexity in- creases if stringent performance specifications are deman- ded. The complexity arises because of variable freguency power supply, aç signals processing, and complex dynamic of the aç machines. The induction machines can have vari- ous methods of control, and the particular method to be adapted depens of the nature of the application. The decision on control strategy should be based on the fol- lowing general guestions: 1.What types of power converters should be used? 2.Should the control be öpen loop ör closed loop? 3.Is it a position-speed-or torgue-controlled system? 4.Should it be a one-quadrant, two-quadrant, on four-guadrant drive system? 5.What are the accuracy and response-time regui- rements? 6.Is it a single-machine ör a multimachine drive? 7.What is the range of speed? 8.Do pulsating torgue, harmonics and power factor need control? The induction motor drive system is basicly a mul- tivariable control system, and there för in principle the state variable control theory should be applicable. Here the voltage and freguency are the control inputs and the outputs may be speed, position, torgue air gap flux, sta¬ tor current, ör any combination of them. The machine model given by eguations (1), (2), (3) is nonlinear beca¬ use of the presence of the wr term in the impedance matrix of eguation (1) and produced terms in eguation (3). in ad- dition, the parameters of the machine may vary with satura- tion, temperature and skin effect, adding further nonline- arity to the system. The system is also discrete time beca¬ use of sampling nature of the converters. The discrete time effect of the converters and controller can, of cour- se, be neglected if the machine is sluggish, which is nor¬ mal ly the case. Vq Rs*PLsWeLs PLm weLm ig Vdls5|-urLsRs*PLs -ueLm PLm $ (1) ^; PLm(we- nı uı f-=(§-)2(6) Hl Ql J^L. = (Q_)3/7t P (O '('' mi yl it is critical to note that (5), (6) and (7) are only useful in describing the shift that occurs with pumps ör fan curves when changing from öne speed to another. in actual applications the power required by pump ör fan may not be reduced to the cube of flow. This is because the pump ör fan head developed at reduced flows and speeds is a function not only of the pump ör fan characteristics, but also of the nature of the system in which the equip- ment is installed. The reguired system head characteristic that must be matched by the developed pumps head is made up of two components, the static head and frictional head. A pump- ing ör fan system can have the two components in virtual- ly any proportion depending on the application, but the head reguired at reduced flow conditions, and thus the horse power can vary dramatically, depending on what those proportions are. This is because static head has constant characteristic across the flow range whereas frictional head will normally vary with the square of flow. Because of this, the energy savings at reduced speeds will be con- siderably different for the two system. As a consequence while horse power will drop a slight amount for the constant-speed case with throttling, it will go down as the cube of the flow for adjustable- speed application. - ix -Energy Usage Evaluation and Financial Analysis it can be noted that the important and difficult part of an adjustable-speed energy savings analysis is the data gothering and determination of the shaft power reguired by the pump ör fan under the various operation conditions. The following is a summary of a suggested evaluation procedure from that point on. 1.Calculate the reguired pump ör fan power för each flow case för ASD's and the base comperison system using(4) 2.For each flow condition för the ASD and the base com- parison system, determine actual load efficiencies of the electrical components of each drive system and cal- culate the total input kilowatts according to (8) p* = v vvt ikw P :input kilowatts P :shaft power nd:Gear efficiency n :motor efficiency r|, :control system efficiency n.:transformer efficiency Note: Delete the efficiency in the preceding förmula for any component that is not present. 3.Determine the total energy usege for each flow condi¬ tions for both of the system (assuming an annual evalu¬ ation period) E = P.t.8,76 |MWh|(9) t: p.u of time at flow condition. 4.Determine the total annual energy consumed by ASD and base comparison system at every flow conditions. The difference between the total energy consumption for each case is the energy saving. A simple payback calculation taking only power costs into account may be sufficient to determine project viability, based on an assumed energy cost as in (10) T : Pay back time (years) - Total project cost g.** Energy cost TL/kWhxE k ' - x -A more sophisticated financial analysis tool may be warranted. There are two widely accepted measurements of a project viability; the simple time to payback (Tg) and the return on investment (K). The K is more sophisticated measurement than the Tg since it recognizes the time value of money. The rea- txonship between investment, saving and K is indicated by (11) n max Y = E 1 S J (ID n=l (1-K)n Where Y: initial capital expenditure in TL s: Yearly savings in TL n: year n : length of evaluation period, in years K: return on investment, in per unit. A simple way to look at the K is that it would be equ ivalent to the interest rate you would receive if you took the money spent on a capital project and instead in vested it in a CD at your bank. 1. If the annual energy saving and K is determined. Over an evaluation period the investmen can be calculated from- (11) and the result is compared with the initial in vestment. For the project economic viability the initial investment cannot exceed the result. 2. Normally the initial investment is known and is required to calculate the percent K. For the economic via bility the K should be equal or greater than interest rate. In order to do this calculation by hand the itera tive calculation or infinite series must be made first. If the equation (11) is written as an infinite series, it will probably equal to the term of (12) Y = s 1 (K“1) ”11 (12) K(K-l)n It is easy to do this calculation by computer as illustrated by the examples from Ereğli iron and steel works in the last section. XI

Benzer Tezler

  1. Tez No

    554347

    High voltage conversion efficiency charge pump based power management integrated circuit for bioimplants

    Biyoimplantlar için gerilim dönüştürme verimi yüksek yük pompası tabanlı güç yönetimi tümdevresi

    MELİH BİLMEZ

    Yüksek Lisans

    İngilizce

    İngilizce

    2019

    Elektrik ve Elektronik Mühendisliğiİstanbul Teknik Üniversitesi

    Elektronik ve Haberleşme Mühendisliği Ana Bilim Dalı

    DR. ÖĞR. ÜYESİ TUFAN COŞKUN KARALAR

  2. Tez No

    23693

    Tam satrifüj pompalarda, kapalı ve yarı açık fanlarda ara kanatçık ilavesinin pompa performansına etkisi

    Başlık çevirisi yok

    KEMAL TOPRAK

    Yüksek Lisans

    Türkçe

    Türkçe

    1992

    Makine MühendisliğiAnadolu Üniversitesi

    Makine Mühendisliği Ana Bilim Dalı

    DOÇ. DR. YAŞAR PANCAR

  3. Tez No

    29082

    Tam santrifüj pompalarda tek, iki ve çok kanatlı kapalı ve yarı açık fanlarda geometrik benzerlik bağıntılarının teorik ve deneysel yollarla mukayesesi

    Başlık çevirisi yok

    YAŞAR ÖZÜDOĞRU

    Yüksek Lisans

    Türkçe

    Türkçe

    1993

    Makine MühendisliğiAnadolu Üniversitesi

    Makine Mühendisliği Ana Bilim Dalı

    DOÇ. DR. YAŞAR PANCAR

  4. Tez No

    96968

    Tam santrifüj pompalarda yarı açık fanlarda ara kanatçık ilavesinin pompa performansına etkisi

    The Effect of adding secondary blade to pump performance in centrifugal pumps

    ESRAH ÖNEN (GÖRAL)

    Yüksek Lisans

    Türkçe

    Türkçe

    2000

    Makine MühendisliğiEskişehir Osmangazi Üniversitesi

    Makine Mühendisliği Ana Bilim Dalı

    PROF. DR. YAŞAR PANCAR

  5. Tez No

    537586

    Tekstil sanayinde enerji verimliliği: Entegre bir tekstil fabrikası örneği

    Energy efficiency in textile industry: An integrated textile factory example

    MEHMET ÖNDER SERT

    Yüksek Lisans

    Türkçe

    Türkçe

    2018

    EnerjiKocaeli Üniversitesi

    Enerji Sistemleri Mühendisliği Ana Bilim Dalı

    PROF. DR. DURMUŞ KAYA

Geri Dön