Türkiye'deki mevcut konut binalarının enerji verimliliği iyileştirmeleri ile nSEB'e dönüştürülmesi: Finansal bariyerler ve çözüm önerileri
Transformation of existing residential buildings in Turkey into nZEB with energy efficiency improvements: Financial barriers and solution proposals
Yazar: BEGÜM DİKER
Danışman: DOÇ. DR. FATİH YAZICIOĞLU
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Mimarlık Ana Bilim Dalı / Yapı Bilim Dalı
Derece: Doktora, 2024
Konu: Mimarlık = Architecture

Özet:
İklim değişikliği, küresel ısınma ve çevresel tahribat sorunları, son dönemde etkilerine doğrudan maruz kaldığımız seviyelere ulaşmıştır. Özellikle sanayileşme sonrasında, kentlerdeki insan kaynaklı emisyonların ve enerji ihtiyacının dramatik seviyelerde artış göstermesi ulusal ve uluslararası birçok platforma konu olmuştur. Kentlerdeki binaların enerji tüketiminde ve küresel emisyonlarda önemli bir paya sahip oluşu ise binalarda enerji performansının iyileştirilmesine yönelik çalışmalara ivme kazandırmıştır. Bu kapsamda, Avrupa Birliği başta olmak üzere pek çok dünya ülkesi, binalarda enerji tüketiminin dengelenmesi ve emisyonların azaltılmasına yönelik çalışmalar yürütmektedir.

2010 yılında Avrupa Komisyonu tarafından yayımlanan Bina Enerji Performans Direktifi ile 'neredeyse sıfır enerjili bina (nSEB)' kavramı literatüre girmiş ve binaların enerji performansının iyileştirilmesi sürecinde üye devletlerin maliyet etkin çözüm önerilerine odaklanılması istenmiştir. Direktife göre ülkelerin, kendi koşullarına uygun nSEB seviyelerini belirlemeleri; bunun için gerekli mevzuat düzenlemeleri yapmaları ve binalarda enerji verimliliği uygulamalarını finansal araçlarla desteklemeleri gerekmektedir. Türkiye'de, 2007 yılı itibarıyla enerji verimliliğine yönelik yasal düzenlemeler oluşturulmuştur; ancak nSEB tanımı 2022 yılında mevzuata girmiştir. Binalarda enerji verimliliği uygulamalarına yönelik finansal destekler ise oldukça kısıtlıdır. Bu nedenle, mevcut binalarda enerji performansını iyileştirmeye yönelik uygulamaların önündeki en önemli zorluklardan birinin, bu uygulamaların finanse edilmesi olduğu düşünülmektedir.

Bu çalışmada, Türkiye'deki mevcut bina stokunun önemli bir bölümünü oluşturan konut binalarının, yapılacak enerji verimliliği iyileştirmeleri ile nSEB'e dönüştürülmesi probleminden yola çıkılmış ve bu kapsamda alınabilecek teknik önlemlerin belirlenmesi, karşılaşılabilecek finansal bariyerlerin tanımlanması ve bunlara ilişkin çözüm önerileri getirilmesi amaçlanmıştır.

Bu kapsamda, 2007-2019 yılları arasında yapı ruhsatı aldığı ve İstanbul'da (2. İklim bölgesi) olduğu kabul edilen 4 katlı bir mevcut konut binasını temsil eden referans binaya ilişkin gerekli tüm istatistiksel veriler toplanmış ve DesignBuilder programına aktarılarak modellenmiştir. Referans binanın nihai ve birincil enerji tüketimi cinsinden enerji performansı dinamik simülasyon yöntemi ile saatlik bazda hesaplanmıştır (EnergyPlus). Buna göre, referans binada ısıtma, soğutma, aydınlatma, sıcak su sistemi ve elektrikli ev aletlerine ilişkin birincil enerji tüketimi 165,71 kWh/m2y'dir. Bir sonraki adımda, referans binanın enerji performansını iyileştirmeye yönelik tekil önlemler ve önlem paketlerinden oluşan toplamda 41 adet senaryo belirlenmiştir. Önlemler ve önlem paketlerinin her biri enerji verimliliği, ilk yatırım maliyeti, yıllık enerji maliyeti ve 30 yıllık küresel maliyetler üzerinden değerlendirilmiştir.

Enerji verimliliği bakımından yapılan değerlendirmelerde, yapı kabuğunda ele alınan senaryolarda (S1-S8) en fazla %3 oranında iyileştirme sağlanmıştır. En verimli tekil önlemler, %14,61'lik iyileştirme oranı ile yerden ısıtma sistemi (ISITMA-DS) ve %14 iyileştirme oranı ile fotovoltaik sistem (PV) senaryolarıdır. Yapı kabuğunda ele alınan önlemlere ek olarak ısıtma, aydınlatma sistemleri ile yenilenebilir enerji entegrasyonlarının çalışıldığı senaryolarda ise (S9-S22), referans binaya oranla en fazla %45,53 oranında iyileştirme sağlanmıştır. Küresel maliyeti referans binaya oranla düşük olan tek önlem 1652,94 TL/m2 ile PV senaryosudur (%1,34 daha düşük).
Yapılan değerlendirmeler sonucu, referans binaya uygulanan enerji verimliliği önlemlerinin yüksek maliyetli uygulamalar olduğu görülmüştür. Bu uygulamaların, bina sahiplerine ya da son kullanıcıya yüklendiği ve herhangi bir teşvik ya da hibe ile desteklenmediği durumlarda yatırımın finanse edilmesi oldukça zorlaşmaktadır.

Bu bağlamda, Türkiye'de halihazırda mevcut binalardaki enerji verimliliği iyileştirmelerini kapsamayan finansman sistemine bir öneri getirilmiş, -Avrupa'daki öne çıkan uygulama örneklerinden de yararlanılarak- Türkiye şartları için finansal bir model uyarlaması yapılmıştır. Bu uyarlama yapılırken, mevcut literatürdeki tekil önerilerden beslenilmiş ve bütünleşik bir yaklaşım ile mevcut binaların nSEB kriterleri doğrultusunda enerji verimli dönüşümünün sağlanması hedeflenmiştir.
Önerilen finansal model uyarlaması, enerji verimliliğinin finanse edilmesinde görev alacak kurum ve paydaşlar ile birbirleri arasındaki ilişki ağını ortaya konması ve uygulanacak finansal araçların belirlenmesi ile bütünleşik bir bakış açısı sunmaktadır.

Gelecekteki çalışmalar için, binalarda enerji verimliliğinde uygulanabilecek finansal araçların (ESCO, EVYS ve devlet teşvikleri gibi) küresel maliyete etki oranlarının, nicel analiz yöntemi ile araştırılması ve önem derecelerinin belirlenmesi önerilmektedir. Ayrıca, konut binalarında enerji verimliliği tekil örnekler üzerinden ele alınarak, uygulanabilecek finansal teşvik seçeneklerinin bina özelinde etkilerinin değerlendirilmesi yapılabilir.

Abstract:
Climate change, global warming, and environmental degradation issues have reached levels that we are directly exposed to in recent times. Especially after industrialization, the dramatic increase in anthropogenic emissions and energy demand in cities has become a topic of discussion in many national and international platforms. The fact that buildings in cities have a significant share in energy consumption and global emissions has accelerated studies on improving energy performance in buildings. In this context, many world countries, especially the European Union, are carrying out studies to balance energy consumption in buildings and reduce emissions.
The Energy Performance of Buildings Directive (EPBD), published by the European Union for the energy performance of existing and new buildings, is one of the main documents within the scope of energy efficiency. The directive, which was first published in 2002 and later revised in 2010 and 2018, covers issues such as reducing greenhouse gas emissions, the use of renewable energy technologies in buildings or in the immediate surroundings of buildings, and determining a common methodology for calculating energy consumption in buildings. Especially with the EPBD Recast published in 2010, the concept of 'nearly zero energy building (nZEB)' had taken place in literature and member states were asked to focus on cost-effective solution proposals in the process of improving the energy performance of buildings. According to the directive, countries must determine nZEB levels appropriate to their own conditions; for this, they need to make the necessary legislative arrangements and support energy efficiency practices in buildings with financial instruments. In Turkey, legal regulations for energy efficiency have been established as of 2007; however, the nZEB definition entered into legislation in 2022. Financial support for energy efficiency applications in buildings is quite limited. Therefore, it is thought that one of the most important challenges for applications to improve energy performance in existing buildings is the financing of these applications.
This study is based on the problem of transforming residential buildings, which constitute a significant portion of the existing building stock in Turkey, into nearly zero energy buildings through energy efficiency improvements. Within this scope, the aim is to identify technical measures that can be taken, define potential financial barriers, and propose solutions related to them.
The aim of the study is to discuss to what extent the energy efficiency measures determined can be implemented with existing financial support systems by making energy and cost analyses. In this context, proposing a financial support model that can be applied to energy efficiency improvements in buildings in Turkey is also one of the main objectives of the study.
The first part of the study includes explanations about the purpose, scope, method, hypothesis and eigen value of the study. The second part contains a detailed literature review on the concept of energy efficiency and nZEB in buildings. In this context, firstly, the concepts and definitions related to nZEB in the national and international literature are discussed. In Section 2.1.1, approaches to balancing calculation methodologies of nZEBs are explained. In Section 2.2, legal legislation regarding energy efficiency in the world is examined. In this context, laws, regulations, standards and action plans are mentioned. In Section 2.3, an international literature review was conducted on the concept of zero energy building. At this stage, a two-stage analysis was carried out with the help of Scopus database and VOSviewer software. Section 2.4 includes a review of national laws/regulations and legislation on energy efficiency in Turkey. In Section 2.5, the national literature on the concept of zero energy building was examined and information was given mainly about the thesis studies on this subject at the National Thesis Center. In Section 2.6, energy efficiency financing in buildings is examined, focusing especially on Europe, where the old building stock is concentrated, and financial support systems that are being implemented or planned are investigated. Financing mechanisms frequently encountered in international literature are schematized and prominent application examples are cited. In the next step, the financial support systems currently implemented in Turkey and their areas of activity are mentioned. In this context, the stakeholders and their powers and responsibilities were transferred and an evaluation was made based on the limitations and deficiencies in the current system functioning.
In the third section, the methodological framework required for a situation assessment to be carried out on existing residential buildings in Turkey and determined in the EU directive is presented. In this regard, first of all, a reference building that largely represents the physical, climatic and characteristic features of the residential buildings within the scope of the thesis was created and its energy performance was calculated with the help of EnergyPlus software. Then, energy efficiency measures that could be applied to the reference building were determined and the energy performance value was calculated for each. In the next step, data on economic inputs were collected for financial analysis and global cost analyzes of the measures were carried out.
The fourth chapter includes the findings of the analysis and their interpretation within the framework of the criteria determined within the scope of the study. In the evaluation, the most efficient scenarios were examined in terms of energy efficiency, initial investment costs, annual energy costs and 30-year global costs. In this context, the assumptions and limitations of the study are also explained.
In the fifth chapter, firstly a gap analysis was made for residential buildings in the energy efficiency legislation. Afterwards, a proposal was made for the financing system that does not include energy efficiency improvements in existing buildings in Turkey, and a financial model was adapted for Turkey's conditions - making use of good practice examples in Europe. While making this adaptation, a financial model was adapted to improve the energy efficiency of existing buildings in line with the nZEB criteria, based on individual suggestions in the existing literature and with a holistic approach.
In the study, all necessary statistical data regarding the reference building, which represents a 4-storey existing residential building that received a building permit between 2007 and 2019 and is considered to be in Istanbul (2nd Climate Zone), was collected and modeled by transferring it to the DesignBuilder program. The energy performance of the reference building in terms of final and primary energy consumption was calculated on an hourly basis with the dynamic simulation method (EnergyPlus). Accordingly, the primary energy consumption for heating, cooling, lighting, hot water system and electrical appliances in the reference building is 165.71 kWh/m2y. In the next step, a total of 41 scenarios were determined, consisting of individual measures and precaution packages to improve the energy performance of the reference building. Each of the measures and precaution packages were evaluated on energy efficiency, initial investment cost, annual energy cost and 30-year global costs.
In the evaluations made in terms of energy efficiency, a maximum of 3% improvement was achieved in the scenarios (S1-S8) considered in the building envelope. The most efficient individual measures are the underfloor heating system (ISITMA-DS) with an improvement rate of 14.61% and the photovoltaic system (PV) scenarios with an improvement rate of 14%. In the scenarios (S9-S22) where heating, lighting systems and renewable energy integrations were studied in addition to the measures taken in the building envelope, an improvement of 45.53% was achieved at most compared to the reference building. The only measure with a lower global cost compared to the reference building is the PV scenario with 1652.94 TL/m2 (1.34% lower).
As a result of the evaluations, it was seen that the energy efficiency measures applied to the reference building were high-cost applications. In cases where these practices are imposed on the building owners or the end user and are not supported by any incentives or grants, it becomes very difficult to finance the investment.
In this context, a proposal has been made for the financing system that does not include energy efficiency improvements in existing buildings in Turkey, and a financial model has been adapted for Turkey's conditions - making use of good practice examples in Europe. The proposed financial model adaptation offers an integrated perspective by revealing the relationship network between the institutions and stakeholders that will be involved in financing energy efficiency and determining the financial instruments to be applied.
For future studies, the quantitative analysis method is proposed to investigate the impact ratios on global costs of financial instruments such as ESCOs, EEOS and government incentives in order to determine their significance levels. Also, it is recommended to consider energy efficiency in residential buildings through individual examples and to discuss/evaluate the effects of applicable financial incentive options on a building-specific basis.