Değişken devirli sirkülasyon pompalarında enerji verimliliği

Abstract

Artan dünya nüfusu teknolojinin gelişimi ve sanayileşme yarışı, enerjiye olan bağımlılığı sürekli olarak artırmaktadır. Enerjiye olan talebin gün geçtikçe artması, enerji yatırımlarının yüksek maliyetleri ve yeni yatırımların ihtiyacı karşılayamaması sebeplerinden ötürü, mevcut sistemlerin iyileştirilmesi ile ilgili çalışmalar önem kazanmıştır.Özellikle devlet tarafından enerji verimliliği konusunda yapılan düzenlemeler, teşvik ve yasal zorunluluklar enerji verimliliği çalışmalarının artmasına yol açmaktadır. Enerji Verimliliği Kanunu, Binalarda Enerji Performans Yönetmeliği, Enerji Kaynakları ve Enerjinin Kullanımında Verimliliğin Artırılmasına Dair Yönetmelik ve Yenilenebilir Enerji Kanunu bu yasal düzenlemelere örnek verilebilir. Bütün bu düzenlemeler ve sürekli artan enerji fiyatları, işletmeleri enerji tasarrufu yapmaya zorlamaktadır. Değişken hızlı tahrik sistemleri, bir başka deyişle frekans konvertörleri de sağladıkları enerji tasarrufu ve kolay kullanımları ile tahtik sistemleri tasarımında yaygın olarak tercih edilmekte ve popüler bir uygulama haline gelmektedir.Yapılan bu tez çalışmasında sirkülasyon pompaları konusundaki yasal düzenlemeler ve yönetmelikler çerçevesinde değişken devirli sirkülasyon pompaları enerji verimliliği açısından ele alınmıştır. Kapalı devre sistemlerde sirkülasyon pompaları olarak kullanılan santrifüj pompalar, hem enerji verimliliği hem de sistem verimliliği yönünden incelenmiştir.Özellikle paralel çalışan değişken devirli pompaların verimli çalıştırılmaları üzerinde durulmuş ve aynı hidrolik koşullarda değişken devirli sirkülasyon pompalarının paralel çalışma koşulunda eşit frekans ile çalışmalarının enerji açısından en verimli çözüm olacağı görülmüştür. Hem enerji maliyetleri açısından hem de ömür boyu maliyet açısından hesaplamalar yapılmış ve değerlendirilmiştir. Ayrıca, sirkülasyon pompaları için geliştirilen çalışma algoritmaları da enerji verimliliği açısından büyük öneme sahiptir. Basınç kontrol algoritması, sabit ve değişken basınç farkı kontrolü olarak, temelde iki yöntemden oluşmaktadır. Yapılan deneylerde sabit basınç farkı algoritması kullanılmıştır. Literatürde değişken basınç farkı algoritmasının sabit basınç farkı algoritmasına göre daha fazla enerji tasarrufu sağladığı bilinmektedir.

Energy is one of the significant inputs of economic and social development. In this aspect, energy plays an important role for the rasing of the living standards of a society. Sustainable development is possible through energy as well. As known, it appears that upper limits are approached in pump efficiencies and the potential improvements could not be more than a few points. The energy saved through efficiency improvements of pumping systems is related with proper selection, using of pump and the improvement of system design.The dependence on energy is increasing consistently due to the growing world population, development of new technologies and industrialization race. During the past several decades, studies for improving of existing systems has been a popular issue, regarding to increasing demand on energy, high cost and insufficiency of new energy investments.During the past several decades, environmental consciousness of the population has increased dramatically and mankind started to question his effects on the environment. In connection this issues, not just the society but also the customers started to question the environmental effects of the products they use. Increasingly every year, consumers demand low carbon foot print products, which lead manufacturers to produce items that does not harm the environment. As a result energy efficiency on circulation pumps starts to become obsolete and a new research and development processes has been developed.Today energy efficiency is one of the most important subjects for circulation pumps. High efficient pumps are started to use because of both legal regulations. In particular, the regulations made by the government about energy efficiency, such as incentives and legal obligations, led to increase energy efficiency efforts. Energy Efficiency Law, The Energy Performance of Buildings Regulation, Increasing Efficiency Regulation on Using Energy and Energy Resources and Renewable Energy Law are the examples of these efforts. All these regulations and increasing energy prices have the companies to come up new energy efficiency efforts. Variable speed drive systems have become a popular and widely used application on account of their energy saving features and simple usage in the market.Energy consumption and overall life cycle costs of equipment are reduced significantly, permitting operators to run the same production with much less energy. This becomes all the more topical in view of high energy prices and the unacceptability of the energy related emissions on the one hand, and the industrial requirements of fast growing economies.Pumping applications represent a significant opportunity for applying variable speed drives in new, as well as retrofit installations. The majority of pumping applications need to be controlled. It is unlikely that a pump will run continuously at a maximum speed. Variable speed drives are crucial when limiting the life cycle costs of a pump station. The three main costs are energy, initial investment an maintenance. Many analyses show that energy consumption is the dominating element of the life cycle costs. The investment cost of the equipment needed (variable speed drives, motors and pumps) is relatively low when compared to the total life cycle costs. Maintenance is the third main cost component. Active control using a variable speed drive works as a means of preventive maintenancei limiting maintenance costs in many ways. Variable speed control has several benefits in pumping applications. The most important is energy saving. Accurate control of the pump system is another benefit.The use of variable speed drives in pumping applications with variable duty requirements provides the user with a variety of benefits, including potentially significant energy saving and improved reliability achieved by means of speed reduction and avoding part flow operation. Energy savings are primarily realized by running the equipment at high levels of efficiency and optimal operating speeds, matching the generated pump head to the exact system requirements without the use of energy consuming control valves. Running pumps at lower operating speeds and avoiding part flow operation also positively influences component life and between maintenance intervals. The primary mechanical challenge of any variable speed drive application is the wide continuous operating speed range. During the past 10 years, the cost os variable speed devices have come down significantly due to the advances in technology, which allowed widespread applications of variable speed pumps. An increased issue associated with the use of variable speed pumps is to control and optimization of their operation. As a result, in terms of enhancing the operating efficiency, energy efficient control of the variable speed pumps becomes an important issue.In today?s business environment, heating and cooling systems are looking for new strategies to enchase plant performance. An easy and often overlooked means to make a dramatic impact on these systems? performances is through maximazing pumping system efficiency. The assesment of technical and economical advantages gained by using variable speed drives instead of throttling valves on circulation pumps, have been widely publicized in recent years.Circulation pumps are responsible for the circulation of hot and cold water in heating, ventilation and air-conditioning (HVAC) systems. Older non controlled circulation pumps can be one of the most energy consuming electric devices in private household and commercial buildings.In this thesis, within the framework of the legislation and regulations, variable speed circulation pumps are investigated for better energy efficiency. The parallel running variable speed circulation pumps in closed loop systems are also investigated for better energy and system efficiency.Especially, this study is based on parallel running variable speed circulation pumps. Parallel running of the circulation pumps is an important issue and it should be investigated carefully for energy efficient working. Under the same hydraulic conditions, for the same type of parallel running variable speed circulation pumps, with the same speed ratio, the best overall energy efficiency is sought.System control algorithm which developed for the circulating pumps is also an important issue for evaluating energy efficiency. Pressure control algorithm is based on two methods such as constant and variable differential control. In this study, constant differential pressure algoritm was used during the experiments. Besides, in literature, it is known that variable differential pressure algorithm saves more energy.