Kampüs Binalarında Şebekeden Bağımsız Bir Çatı Üstü Fotovoltaik Sistem Tasarımı Ve Benzetimi

Abstract

Yenilenebilir enerji kaynakları, diğer enerji kaynaklarına göre insanlığın enerji talebini karşılıyabilecek en temiz ve güvenilir kaynaklardır. Bu sebeple yenilenebilir enerji kaynaklarından enerji elde edilmesi çalışmaları hızla artmaktadır. Dünyada tüm enerji üretiminde yenilenebilir enerjinin payı %13.4 ve elektrik enerjisi üretimindeki pay ise %22.8 civarında olsa da, yenilebilir enerjiye yapılan yatırım, bu alandaki istihdam oranı ve kurulu güç miktarlarının senelik artışlarına bakılınca, bu konuda dünyanın çok daha hızlı ilerlediği görülmektedir. Bu oranlara benzer şekilde fotovoltaik sistemler, yenilenebilir enerji kaynakları arasında üretim payı olarak düşük bir oranda kalsa da, senelik olarak dünyada %45.5 civarında bir artışa sahiptir. Daha önceden maliyetli bir enerji üretim şekli olarak görülen fotovoltaik sistemler, son yıllarda bu konuda yapılan ilerlemeler ile çok daha cazip hale gelmiştir. Türkiye coğrafi konumu itibariyle çok iyi bir güneş enerjisi potansiyeline sahip olsa da daha çok güneşten sıcak su üretimi için uygulanan ısıl güneş sistemleri alanında faydalanılmıştır. Enerji üretimi konusunda fotovoltaik teknoloji ülkemizde son on yıla kadar yok denecek kadar az bir paya sahipti. Türkiye'de son yıllardaki fotovoltaik kurulu gücündeki artış ise ülkenin hedefleri doğrultusunda çok ümit vericidir. Yenilenebilir enerjinin mutfağı olarak tanımlanan üniversiteler yeşil veya sürdürebilir kampüs projeleri yürütmektedirler. Bu projeler doğrultusunda görece elektrik üretiminin fazla sayılabileceği üniversite kampüsleri için fotovoltaik sistem uygulamaları, hem eğitim ve araştırma hem de elektrik üretimi adına çok güçlü bir alternatiftir. Bu sebeple bir çok üniversite kampüsü için hem teorik hem de uygulamalı çalışmalar yapılmıştır. Bu çalışmada İstanbul Teknik Üniversitesi Ayazağa Kampüsü'nde bulunan Enerji Enstitüsü binaları için şebekeden bağımsız bir fotovoltaik sistem tasarlanmış ve benzetimi yapılmıştır. Tasarım ve benzetim işlemlerinde PV*SOL yazılımı kullanılmıştır. Fotovoltaik sistem uygulamaları açık alan, bina çatıları veya bina cephesi uygulamaları olarak yapılabilmektedir. Açık alan uygulaması için enstitünün uygun bir arazisinin olmaması ve bina cephesi için tasarlanacak bir sistemin de çok maliyetli olacağı ön görülmesi sebebiyle tasarlanacak fotovoltaik sistem için en uygun yer olarak enstitü binalarının çatıları seçilmiştir. Enstitünün elektrik tüketim verileri göz önünde bulundurularak tüm elektrik tüketiminin fotovoltaik sistemler ile karşılanması için gerekli modül adeti hesaplanmıştır. Daha sonra binaların uygun olan çatı alanları için bir ön hesaplama yapılarak çatılara yerleştirilebilecek maksimum modül adet sayısı hesaplanmıştır. Ön hesaplamaların sonucu, çatı alanlarına kurulabilecek maksimum kapasitedeki bir fotovoltaik sistemin enstitünün elektrik tüketiminin yarısından azını karşılayabileceği ortaya çıkmıştır. Şebekeden bağımsız bataryalı bir sistem için böyle sonuç uygundur. PV*SOL yazılımının üç boyutlu tasarım aracı ile enstitü binaları modeli oluşturulmuş ve modüllerin bina çatılarına uygun şekilde yerleştirilmesi ile fotovoltaik sistem tasarlanmıştır. Modül olarak yerli üretim bir model seçilmiştir. Yazılımın otomatik oluşturduğu konfigürasyon seçenekleri doğrultusunda fotovoltaik sistemin diğer ekipmanları olan eviriciler ve bataryalar seçilmiştir. Benzetim sonucu fotovoltaik sistemin yıllık 88.642 kWh elektrik enerjisi üreteceği hesaplanmıştır. Bu miktar enstitünün gerçek yıllık elektrik tüketiminin %25'i kadardır. %72,3 verimle çalışan sistemin performans oranı %79,8 olarak hesaplanmıştır. Birim başına maliyet değeri ise 0,95 TL/kWh olarak hesaplanmıştır.

Compared to the other energy resources the renewable energy are clean and safe resources that can supply energy demand of the human beings. For this reason, recently the usage of the renewable energy resources and hence the studies and researches on the renewable energy have been increased rapidly. The renewables accounted for 13.4% of the global energy production and 22.8% of the world electricity generation in 2015. The penetration of the renewable energy is supposedly increased significantly in the long-term scenarios. The renewable energy sector is demonstrating the capacity of delivering cost reductions provided by the appropriate policy frameworks. While the share of renewable energy in total energy production in the world is 13.4% and the share of electricity energy production is around 22.8%, it is seen that the world is proceeding much faster in this area when considering the investments made in renewable energy, the annual increase in the employment rate and the amount of installed power in this area. Although the energy production by photovoltaic systems holds a smaller share compared to the rest of the renewables energy supply, the increase has been especially high at average annual rates of 45,5% since the year 1990. A breakthrough in cost of photovoltaic power production was observed over the last years due to the massive investment in research and development. Nowadays, the photovoltaic systems are widely common and the photovoltaic generated electricity costs less than before. Therefore, the annual installed capacity in 2016 has been increased by 50% with 76.6 GW compared to the installed capacity in 2015 with 51.2 GW. Besides, the World total installed power capacity has been reached the value of 306.5 GW. As it is in the previous years, also in 2016, China, USA and Japan has protected their ranks in the photovoltaic markets. China has increased the installed photovoltaic power capacity to a total of 77,9 GW by adding more 34,5 GW in 2016. This value equals to the quarter of the world total capacity. The photovoltaic power investment in USA was increased by 98% in 2016 with the capacity of 14,8 GW. Japan as the third largest country in the market has increased the installed photovoltaic power capacity by 8.6 GW in 2016. The photovoltaic power investment in Europe has been decreased by 22 % and the installed power in 2016 was 6,7 GW. In 2016, the lowest photovoltaic sale contract in the history with 24,4 USD / MWh was signed in Abu Dhabi. According to the US investment bank Lazard Capital's latest levelized cost of electricity (LCOE), the cost of the large-scale solar power plants are more cheaper than the new combined cycle gas turbines, coal and nuclear power plants. In spite of having some disadvantages, the photovoltaics systems have got many advantegous such as the direct conversion of sunlight into electricity, the absence of mechanical or moving parts, the absence of noise problem, the failure due to reaching high temperatures, the creation of pollution, and the long and durable life. The photovoltaic energy has a wide range of microwatt and megawatts. In the photovoltaic systems, the solar energy is used directly as a free and inexhaustible source of energy. Due to possesing the insufficient fossil energy sources Turkey is largely dependent on foreign energy resources. This situation has led the country to go for the new energy sources including renewable energy. For the country, solar energy is among the most predominant sources in terms of the production of the energy among the other renewable energy sources. Turkey has an advantageous of geographical position in terms of solar energy. Unfortunately Turkey mostly used this potential on behalf of solar water heating rather than generating electricity by solar energy. Its potential for electricity generation couldn't be utilized until the regulations and laws were enacted. Though the developments of photovoltaic systems in recent years are encouraging. Turkey's solar industry has just come out of its best year so far, adding about 1.7 GW of new photovoltaic capacity in 2017. Universities always have been focal points of change. The mixture of academic research, student activism and institutional influence has allowed campus communities to promote widespread technical and social transformations. During the last few years, a few of these institutions have begun to lead in renewable energy. With green and sustainable campus projects, the universities have taken a big step towards meeting new environmental goals. Photovoltaic system applications for university campuses, where electricity production is more than comparable to these projects, is a powerful alternative for both education and research as well as electricity generation. At Istanbul Technical University which is one of the leading university in Turkey, the solar energy is used in many different fields. For example, solar charged ITU-BUS and solar lighting have been active in order to create an environment-friendly and sustainable campus within the ITU Green Campus project. The ITU Solar Vehicle Team has designed and produced ARIBA and ARUNA vehicles. ARIBA is a racing car produced by the team for TUBITAK Formula G races. The family car ARUNA is Turkey's first domestic vehicle powered by solar energy. The solar powered boat, produced by the ITU Solar Team, has been the 3rd place in the world. In addition, there are many academic and scientific studies in ITU including the development of selective surface solar collectors, photovoltaic conversion by thin films obtained via electrochemical coating, application of solar batteries and solar cooling. In this study, for the Energy Institute which is in Istanbul Technical University Ayazaga Campus, a photovoltaic system using PV*SOL software has been designed and simulated. Designed system is an off-grid photovoltaic system with batteries. All surfaces in the building such as roofs and facades exposed to direcct solar radiation are, in principle, suitable for the installation of photovoltaic arrays. The chosen system for the Institute is a rooftop type. The inter-row distance of the photovoltaic modules is important for the localization of the system on the roofs. Calculation of inter-row spacing of photovoltaic module is needed to prevent interrow shading. A simple rule for minimum spacing between rows is to allow a space equals to three times the height of the panels. According to this rule, it is calculated that the maximum 385 modules can be installed on the institute's roofs. Taking into account the electricity consumption of the institute, the number of modules needed to meet all electricity consumption with photovoltaic systems has been calculated. The conclusion of the preliminary calculations is that a photovoltaic system at the maximum capacity that can be installed in the roof areas is less than half of the electricity consumption of the institute. This is suitable for a off-grid photovoltaic system with batteries. PV * SOL has a 3D design tool to draw the buildings and design the system. The photovoltaic system has been designed by placing the modules in the appropriate positions on the building roofs. A made in Turkey module was selected for the system. In accordance with the configuration options that the software automatically generates the number/capacity of the inverters and the batteries. The simulated photovoltaic system is estimated to produce an annual electrical energy of 88.642 kWh. This amount is 25% of the actual annual electricity consumption of the institute. The performance ratio of the system with 72.3% efficiency was calculated as 79.8%. Cost per unit is calculated as 0,95 TL / kWh.