Yazar "Arpa, Orhan" seçeneğine göre listele
Listeleniyor 1 - 16 / 16
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Acetone and nanoparticles effect on performance and exhaust emissions of a diesel engine(Elsevier, 20.11.2023) Çılğın, Erdal; Deviren, Halis; Arpa, OrhanThis research investigated the effects of acetone and metal nano magnesium oxides (MNMgOs) on combustion and emissions in diesel engines. Tests were conducted at various load conditions at a speed of 1500 rpm. The results showed that the use of a low percentage (2 %) of acetone led to increases in instantaneous energy changes, cylinder pressures (CP), heat release rates (HRR), mean gas temperatures (MGT), and pressure rise rates (PRR). However, an increase in acetone concentration and the use of Acetone + MNMgOs resulted in a decrease in combustion parameters. Concentrations of 2 %, 5 %, and 10 % acetone reduced carbon monoxide (CO) emissions by 7.85 %, 11.35 %, and 2.23 % respectively, hydrocarbons (HC) by 10.84 %, 15.86 %, and 3.02 % respectively, and nitrogen oxides (NOx) emissions by 3.79 %, 2.02 %, and 10.25 % respectively. The combined use of acetone and MNMgOs resulted in a reduction of 1.10 % in CO emissions, 1.48 % in HC emissions, and 10.62 % in NOx emissions.Öğe Akışkan özelliklerinin sıcaklıkla değişiminin karışık konveksiyon ile ısı transferine etkisinin sayısal analizi(2001) Sivrioğlu, Mecit; Başkaya, Şenol; Arpa, OrhanBu çalışmada yatay, dikdörtgen kesitli kanal içindeki akışta bazı akışkan özelliklerindeki sıcaklığa bağlı olan değişimlerin karışık konveksiyona etkileri sayısal olarak incelenmiştir. Problem üç boyutlu olarak tasarlanmıştır. Problem önce akışkan özellikleri sabit alınarak çözülmüş ve literatürdeki benzer çalışmaların sonuçları ile karşılaştırılarak sonuçların uyum içinde olduğu gözlenmiştir. Daha sonra akışkan özellikleri sıcaklığa bağımlı alınarak problem tekrar çözülmüş ve akışkan özellikleri sabit alınarak elde edilen çözümlerle karşılaştırmıştır. Yapılan çalışmada Reynolds sayısı 250, modifıye Grashof sayısı l.0E+6, 2.0E+6 ve 5.0E+6 olarak alınmış ve akışkan olarak hava kullanılmıştır. Elde edilen sonuçlar akışkan özelliklerindeki sıcaklıkla değişimlerin ısı transferine olan etkisinin önemini göstermektedir.Öğe Atık lastik sıvısından elde edilen benzin benzeri yakıtın benzin ile karıştırılarak motor performans ve egzoz emisyon üzerindeki etkisi(2015) Ayanoğlu, Abdulkadir; Yumrutaş, Recep; Arpa, OrhanBu çalışmada, atık lastik sıvısında üretilen benzin benzeri yakıtın (BBY) ve benzin yakıtına (BY) kütlesel olarak 10%, 20%, ve 30% oranlarında BBY ile yapılan karışımının, buji ateşlemeli (BA) motorda performans ve egzoz emisyon karakteristikleri incelenmiştir. Deneylerde, fren torku, güç, ortalama fren efektif basıncı, fren özgül yakıt tüketimi ve ısıl verimlilik parametleri test edilmiştir. Ayrıca, egzoz gaz sıcaklığı, NO, NOx, CO, CO2, ve HC emisyonları analiz edilmiştir. BBY'nin yüzdeliği BY'de artınca güç, fren torku, ortalama fren efektif basıncı ve termal verimlilik artarken fren özgül yakıt tüketimi azalmıştır. BBY oranin karışımda artirilmasiyla, CO2, NOx, NO emisyonları artarken, CO azalmıştır. Ayrıca, HC ve O2 emisyonu artmıştır. Test sonuclarina gore, numuneler problemsiz olarak yanmistir.Öğe Atık yağlama yağından elde edilen yakıt-motorin karışımlarının motor performansı ve egzoz emisyonlarının araştırılması(Dicle Üniversitesi Mühendislik Fakültesi, 2019) Demir, Mahmut; Arpa, Orhan; Yumrutaş, RecepEndüstrideki hızlı gelişime bağlı olarak atıkların da hızlı bir şekilde arttığı ve çevreyi kirlettiği bilinmektedir. Bu atıkların çevre üzerindeki zararlı etkilerini azaltmak için geri dönüştürme yapılmalıdır. Bunu yaparken de çevreyi kirletmemek gerekir. Bu amaç ile bir çalışma yapılmıştır. Atık yağlama yağlarından (DBY) pirolitik distilasyon yöntemiyle elde edilmiş olan yakıt hacimce %20, %40 ve %60 oranlarında standart motorine katılarak dizel motorunda yakıt olarak kullanılmıştır. Motorun torku, Özgül yakıt tüketimi ve güç gibi performans parametreleri ile azot oksitler (NOX), karbon monoksit (CO), oksijen (O2), hidrokarbonlar (HC) ve hidrojen sülfür (H2S) gibi emisyon parametreleri deneysel olarak incelenmiştir.. Motor hızının artırılmasına bağlı olarak CO emisyonu tüm yakıt karışımları için azalmaktadır. %40 dizel benzeri yakıt - %60 dizel yakıt karışımı 1000 dev/dak ve 2000 dev/dak hızlarında motorine göre yüksek emisyon değerlerine sahip olduğu tespit edilmiştir. Bununla birlikte motorin ile karşılaştırıldığında CO2 emisyonlarının yakıt numuneleri için daha düşük olduğu tespit edilmiştir. 2500 motor devrindeki %20 dizel benzeri yakıt - %80 dizel yakıt karışımı yakıtının emisyonu hariç tüm NO ve NOX emisyonlarının dizel yakıta göre daha az olduğu görülmektedir. %40 dizel benzeri yakıt - %60 dizel yakıt karışımı her devirde motorinden yüksek HC emisyonu üretirken %20 dizel benzeri yakıt - %80 dizel yakıt karışımı tüm devirlerdeki ortalamalar alındığında motorinden daha düşük HC emisyonun üretmektedir.Öğe Desulfurization of diesel-like fuel produced from waste lubrication oil and its utilization on engine performance and exhaust emission(Pergamon-Elsevier Science Ltd, 2013) Arpa, Orhan; Yumrutas, Recep; Kaska, OnderIn this study, desulfurization of diesel-like fuel (DLF) produced from waste lubrication oil, and the effects of desulfurized fuel on engine performance and emissions were investigated experimentally. Firstly, the DLF was produced by using a fuel production system and applying pyrolitic distillation method. After producing the DLF, oxidative desulfurization (ODS) method was applied at a temperature of 50 degrees C in order to decrease the amount of sulfur in the DLF. The sulfur level of the DLF was decreased from 3500 to 420 ppm after the application of ODS method. It was observed that temperature had an important effect on decrement of sulfur content of the DLF. Secondly, characteristic tests such as density, kinematic viscosity, heating value and flash point, sulfur content and distillation tests for the desulfurized fuel named as low sulfur diesel-like fuel (LSDLF) are performed. Finally, the LSDLF and a commercial diesel fuel were used in a diesel test engine to examine their effects on engine performance and emission parameters. In each test, performance and emission parameters for the fuels were measured using the test engine and exhaust gas analyzer. The performance and emission test results indicated that torque, mean effective pressure and brake thermal efficiency for the LSDLF were slightly higher while brake specific fuel consumption, exhaust temperature and emissions of SO2, CO and NOx appeared to be lower than those of the commercial diesel fuel. It was concluded that the LSDLF could be used in diesel engine without any problems in terms of physico-chemical parameters, distillation and performance tests. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.Öğe Enhancing diesel engine efficiency and emission control: A study on hydrogen and water vapor injection(Elsevier Ltd, 2025) Akbalık, Zafer; Arpa, OrhanIn this study, the effects of injecting water vapor and hydrogen into a diesel engine on engine performance and exhaust emissions were experimentally investigated. The experiments were carried out in three stages: running the engine on standard diesel fuel, adding 250 g/h of water vapor to the intake manifold and finally injecting 0.17 l/min of hydrogen and 250 g/h of water vapor together. The hydrogen injection increased engine power, but the combination of water vapor and hydrogen caused a drop in torque. Significant reductions in carbon monoxide and hydrocarbon emissions were observed, particularly with the steam/hydrogen mixture, while nitrogen oxide emissions were lowest with this mixture. Hydrogen injection reduced specific fuel consumption, while steam injection increased it. Exhaust temperatures increased with hydrogen injection and decreased with steam injection. The study showed a 3.48% increase in engine power with hydrogen injection and a 6.91% increase in efficiency at 1500 rpm with combined water vapor and hydrogen injection. A 6.4% reduction in specific fuel consumption up to 2000 rpm was also observed with this mixture. Nitrogen oxide emissions were lowest up to 1750 rpm with water vapor injection, while the combination of hydrogen and water vapor produced significant reductions at all engine speeds. Exhaust temperatures dropped to 596.3 °C with the hydrogen and water vapor mixture. These results indicate that the injection of hydrogen and water vapor is an effective method of improving the performance and emissions of diesel engines. © 2024 Hydrogen Energy Publications LLCÖğe Evaluation, characterization, and engine performance of complementary fuel blends of butanol-biodiesel-diesel fromAleurites moluccanusas potential alternative fuels for CI engines(Sage Publications Ltd, 2020) Atabani, A. E.; Mekaoussi, M.; Uguz, Gediz; Arpa, Orhan; Ayanoglu, Abdulkadir; Shobana, SuthaBiodiesel has gained worldwide attention due to its renewable aspects. However, it needs more quality improvement. Recently, butanol has been considered as a favorable alternative fuel or additive over methanol and ethanol in compression ignition (CI) engines. In this regard, the present work deals with the evaluation of butanol-diesel-biodiesel blends as potential alternative fuels. In this work, biodiesel has been produced fromAleurites moluccanusoil followed by blending with Euro-diesel and butanol. Important characteristics such as kinematic viscosity, density and cloud point besides FT-IR, UV-vis spectra, TGA, DSC and NMR (C-13 and(1)H) were analyzed. Some important engine and emission performance parameters, such as BP, BSFC, CO, HC, NO(x)and EGT were also studied in this work. Results revealed that blending butanol and Euro-diesel with biodiesel improves the properties of pure biodiesel such as kinematic viscosity (2.41-3.55 mm(2)/s) and density (841.8-884.6 kg/m(3)), while maintaining an acceptable range for cold flow properties that are analogous to Euro-diesel. In addition, reduction in BP (24.65-26.35%), HC (52.57-38.71%), and CO (39.18-30.4%) was observed for all the blends at full load compared to Euro-diesel. However, increases in both BSFC (38.17-41.14%) and NOx(24.18-8.35%) were observed. Overall, the blends appear to be good alternatives to biodiesel-diesel blends. Thus, butanol-biodiesel-diesel blends can be considered as potential sustainable fuels for fossil diesel.Öğe Experimental investigation of Gasoline-Like Fuel obtained from waste lubrication oil on engine performance and exhaust emission(Elsevier, 2010) Arpa, Orhan; Yumrutas, RecepExperimental investigation on engine performance and exhaust emission of a gasoline engine fueled by Gasoline-Like Fuel (GLF) was performed in this study. The GLF was obtained from waste lubrication oil (WLO) using the pyrolitic distillation method. Firstly, the WLO collected in a tank was particulates removed by a refining process. The refined lubrication oil samples were taken into a reactor and blended with calcium oxide (CaO) 2,4,6,8, and 10 wt.% to remove sulphur in the oil. The blended samples were heated in the reactor and then distilled to decrease sulphur and to produce fuel samples. Distillation tests and characteristics of the produced fuel such as density, flash point and lower heating value were examined. The experimental results indicated that the CaO at 2 wt.% had the highest effect on decreasing the amount of sulphur content in the lubrication oil. Fuels produced using 2 wt.% CaO were separated into two parts which were light fuel with 20 wt.% and heavy fuel with 60 wt.% of the total WLO. Remaining of the WLO is about 20 wt.%, which is rejected from the reactor. The light fuel, referred to as GLF and gasoline samples are used to investigate the effect of the GLF on performance and emissions of a 1300 cm(3) spark ignited engine manufactured by Fiat. The engine used in the study has specifications of four-stroke and four cylinders, water cooled, fueled with carburetor and naturally aspirated. Each cylinder has a bore of 76 mm and a stroke of 71.5 mm. The experimental results showed that the GLF had a positive effect on brake power, brake thermal efficiency, mean effective pressure and specific fuel consumption. The GLF also raised CO emission and exhaust temperature, but it decreased hydrocarbon (HC) in the exhaust. (C) 2009 Elsevier B.V. All rights reserved.Öğe Experimental investigation of the effects of diesel-like fuel obtained from waste lubrication oil on engine performance and exhaust emission(Elsevier Science Bv, 2010) Arpa, Orhan; Yumrutas, Recep; Argunhan, ZekiIn this study, effects of diesel-like fuel (DLF) on engine performance and exhaust emission are investigated experimentally. The DLF is produced from waste engine lubrication oil purified from dust, heavy carbon soot, metal particles, gum-type materials and other impurities. A fuel production system mainly consisting of a waste oil storage tank, filters, a reactor, oil pump, a product storage tank, thermostats and control panel is designed and manufactured. The DLF is produced by using the system and applying pyrolitic distillation method. Characteristics, performance and exhaust emissions tests of the produced DLF are carried out at the end of the production. The characteristic tests such as density, viscosity, flash point, heating value, sulfur content and distillation of the DLF sample are performed utilizing test equipments presented in motor laboratory of Mechanical Engineering Department, University of Gaziantep, Turkey. Performance and exhaust emission tests for the DLF are performed using diesel test engine. It is observed from the test results that about 60 cc out of each 100 cc of the waste oil are converted into the DLF. Characteristics and distillation temperatures of the DLF are close to those values of a typical diesel fuel sample. It is observed that the produced DLF can be used in diesel engines without any problem in terms of engine performance. The DLF increases torque, brake mean effective pressure, brake thermal efficiency and decreases brake specific fuel consumption of the engine for full power of operation. (C) 2010 Elsevier B.V. All rights reserved.Öğe Fuels properties, characterizations and engine and emission performance analyses of ternary waste cooking oil biodiesel-diesel-propanol blends(Elsevier, 2019) Bencheikh, Kamel; Atabani, A. E.; Shobana, Sutha; Mohammed, M. N.; Uguz, Gediz; Arpa, Orhan; Kumar, GopalakrishnanApplication of biodiesel synthesized from waste-based raw materials with numerous solvents (higher chain alcohols) in diesel engines is a topic of great interest. This article examines the effect of biodiesel-diesel-propanol ternary blends. Physio-chemical properties, fatty acids composition (FAC), FT-IR, TGA, DSC, NMR along with some selected engine and emissions performance parameters were examined. Biodiesel was produced from waste cooking oil and exhibits excellent FAC that yields kinematic viscosity, cetane number, oxidation stability, higher heating value and iodine value of 3.93mm(2)/s, 58.88, 7.43 h, 39.45 MJ/kg and 64.92 g/100 g. Propanol blended biodiesel depicted an affirmative improvement in cold flow properties and decremented density. FT-IR and NMR results confirms the existence of biodiesel-diesel-propanol and prove their qualities as reliable methods. DSC and TGA results confirm that propanol reduces the onset and crystallization temperatures of the blends. Engine and emissions performance revealed that propanol addition further increased brake specific energy consumption (BSEC) and brake specific fuel consumption (BSFC) and reduced carbon monoxide (CO), exhaust gas temperature (EGT), nitrogen oxides (NOx) and smoke. This study proves the feasibility of the ternary blends with rewarding benefits in cold flow properties and densities besides acceptable engine and emissions performance results.Öğe Güneş enerjisi destekli vakum distilasyon yöntemi ile deniz suyundan tatlı su eldesinin enerji analizi(Dicle Üniversitesi Mühendislik Fakültesi, 2023) Mungan, Mükerrem Sinem; Arpa, OrhanGünümüzde tüm dünyanın sorunu haline gelen temiz su ihtiyacını karşılamak için yeni çözümler bulunması gerekmektedir. Bu çözümlerden bir tanesi de deniz suyundan tatlı su elde edilmesidir. Üç tarafı denizlerle kaplı olan ülkemiz hem bu açıdan hem de bu sistemler için gerekli olan enerji göz önüne alındığında yenilenebilir enerji kaynaklarından olan güneş enerjisini kullanmak açısından da oldukça şanslı bir konumda bulunmaktadır. Bu çalışmada güneş enerji destekli vakum destilasyon yöntemi kullanılarak deniz suyundan tatlı su elde edilmesinin teorik analizi yapılmıştır. Sistem için gerekli olan enerji ihtiyacı da yine güneş enerjisi kullanılarak PV paneller tarafından sağlandığı düşünülmüştür. Sistemden vakum altında ve atmosferik basınçta üretilecek olan su miktarları hesaplanarak kıyaslama yapılmış ve vakum altında üretim yapılmasının avantajları ve dezavantajları değerlendirilmiştir. Sistemin maliyet analizi de yapılmış olup yaklaşık olarak üretilecek suyun metreküp fiyatı belirlenmiştir. Bu çalışmada İzmir ili iklim koşulları ve Ege denizi değerleri kullanılmıştır. Yapılan çalışma sonucunda 100,30,20,10 ve 5 kPa basınç altında elde edilen su miktarları, sistemin enerji ihtiyacı hesaplanmış ve maliyet analizi yapılarak m3 su maliyeti hesaplanmıştır. Hesaplamalar sonucunda en yüksek su üretimi 5 kPa basınç altında elde edilmiş olup maliyeti yıllık üretime göre 19.50₺ olarak hesaplanmıştır.Öğe Hidrojen Yakıt Hücreleri: Temiz Geleceğin Anahtarı(Kirikkale University, 2024) Bektaş, Mehmet Ali; Arpa, OrhanHidrojen yakıt hücreleri, temiz enerji kaynaklarının geleceğini şekillendirebilecek önemli bir teknolojidir. Bu teknoloji, sıfır emisyonlu enerji üretimini ve sürdürülebilir taşıt sistemlerini mümkün kılarak çevre dostu bir geleceğin anahtarını sunmaktadır. Hidrojen yakıt hücreleri, hidrojen gazını kullanarak elektrik enerjisi üretir ve sadece su buharı emisyonu verir. Bu nedenle, atmosfere zararlı emisyonlar bırakmadan enerji üretimi ve taşıt sistemlerine temiz bir alternatif sunarlar. Bu çalışmada; hidrojen yakıt hücreleri teknolojisinin temel prensiplerini, avantajlarını, dezavantajlarını, sürdürülebilirlik potansiyelini, büyüme beklentisini, karşılaşılan zorlukları, yaygınlaşması için gereken adımları ve fırsatları ayrıntılı bir şekilde ele almaktadır. Hidrojen yakıt hücreleri, temiz enerjiye olan talebin artmasıyla birlikte büyüme potansiyeline sahiptir. Yeşil hidrojen üretim yöntemlerinin geliştirilmesi, altyapının genişletilmesi ve hükümet teşvik politikaları gibi çözümler, bu teknolojinin yaygınlaşmasına katkı sağlayabilir. Makale, hidrojen yakıt hücreleri teknolojisinin gelecekteki temiz enerji dönüşümünde önemli bir role sahip olduğunu vurgulayarak, sürdürülebilirlik hedeflerine ulaşmada potansiyel bir anahtar olduğunu gösterir. Bu bilgiler, hidrojen teknolojisinin yaygın kabulünü ve kullanımını teşvik etme yolunda literatüre önemli bir katkı sağlar.Öğe Hydrogen Fuel Cells: The Key to Clean Future(2024) Arpa, Orhan; Bektaş, Mehmet AliHydrogen fuel cells are an important technology that can shape the future of clean energy sources. This technology offers the key to an environmentally friendly future by enabling zero-emission energy production and sustainable vehicle systems. Hydrogen fuel cells produce electrical energy using hydrogen gas and emit only water vapor. Therefore, they offer a clean alternative to energy production and vehicle systems without releasing harmful emissions into the atmosphere. In this study; It discusses in detail the basic principles, advantages, disadvantages, sustainability potential, growth expectation, challenges encountered, steps and opportunities required for its widespread use of hydrogen fuel cells technology. Hydrogen fuel cells have growth potential as the demand for clean energy increases. Solutions such as developing green hydrogen production methods, expanding infrastructure and government incentive policies can contribute to the widespread use of this technology. The article highlights that hydrogen fuel cells technology has an important role in the future clean energy transition, demonstrating that it is a potential key to achieving sustainability goals. This information makes a significant contribution to the literature towards promoting widespread acceptance and use of hydrogen technology.Öğe Perspective of safflower (Carthamus tinctorius) as a potential biodiesel feedstock in Turkey: characterization, engine performance and emissions analyses of butanol-biodiesel-diesel blends(Taylor & Francis Ltd, 2020) Al-Samaraae, R. R.; Atabani, A. E.; Uguz, Gediz; Kumar, Gopalakrishnan; Arpa, Orhan; Ayanoglu, Abdulkadir; Mohammed, M. N.Safflower (Carthamus tinctorius) is widely farmed in Turkey. This study investigates the physicochemical properties of safflower biodiesel and its blends with Euro diesel and butanol. A polynomial curve-fitting method was used to predict kinematic viscosity and density of the ternary blends. Furthermore, characteristics such as DSC, FT-IR, UV-Vis and TGA were adopted to evaluate the influence of butanol addition on biodiesel-diesel blends. Engine performance parameters such as BP, torque and BSFC and emissions such as CO, HC, NO(x)and EGT were studied. Safflower methyl ester satisfied both EN 14214 and ASTM D 6751 standards regarding viscosity, flash point and density. However, iodine value was quite high. Oxidation stability fails to satisfy either standard. This is due to the high level of unsaturated fatty acids (91.05%). A reduction in BP, torque, HC and CO coupled with an increase in BSFC, NO(x)emissions and EGT was observed for all blends compared to Euro diesel. Overall, all blends appear to be good alternatives to biodiesel-diesel blends. This work supports that biodiesel can be blended with diesel and butanol as ternary blends (up to 20%) for use as a fuel in compression ignition (CI) engines. Therefore, combustion characteristics of blends shall be further investigated.Öğe Production of diesel-like fuel from waste engine oil by pyrolitic distillation(Elsevier Sci Ltd, 2010) Arpa, Orhan; Yumrutas, Recep; Demirbas, AyhanThe aim of this study is to obtain diesel-like fuel from waste lubrication engine oils by pyrolitic distillation method, which can be used in diesel engines. With this aim in mind, waste engine oil is collected in a tank, and it is purified from contaminants such as dust, heavy carbon soot, metal particles, gum-type materials and other impurities by filtering in the process prepared earlier. To investigate effects of additives known as sodium carbonate (NaCO3), zeolite and lime (CaO) on density, viscosity, flash point, sulfur content, heating value and distillation temperature, the purified oil samples are blended separately with additives having mass basis of 2%, 4%, 6%, 8% and 10%. The mixed samples are exposed to pyrolitic distillation process to produce fuels to be used in engines. Thermal and physical properties of the produced fuels such as density, flash point, viscosity, sulfur content, heating value and distillation temperatures are examined. From these results the CaO with a ratio of 2% has the highest effect on decreasing of sulfur content of the waste engine oil and on acquiring the most suitable distillation temperatures close to values of a diesel fuel. Diesel-like fuel (DLF) is obtained as 60% of the waste lubrication engine oil. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Theoretical and experimental investigation of total equivalent temperature difference (TETD) values for building walls and flat roofs in Turkey(Elsevier Sci Ltd, 2009) Kaska, Oender; Yumrutas, Recep; Arpa, OrhanThe aim of this study is to find time lag (TL), decrement factor (DF) and total equivalent temperature difference (TETD) values for multilayer walls and flat roofs of buildings using experimental and theoretical methods, and to compare the experimental results with theoretical ones. The TETD is a method for calculating cooling load due to heat gain from the walls or flat roofs, and it can be obtained using values of inside and outside air temperatures, solar radiation, TL and DF. The TL and DF depend on the highest and the lowest temperatures at the inner and outer surfaces of the walls or flat roofs, and the time periods involved in reaching these temperatures. Hence, two testing rooms each consisting of four multilayered walls and a flat roof, air conditioner, measuring elements are built to measure all required temperatures. The required temperatures, which are hourly inside and outside air temperatures, and surface temperatures of each structure layer, are measured in every minute during testing periods of the 2007 summer season of Gaziantep, Turkey. Hourly solar radiation values on the walls are computed using hourly measured solar radiation on a horizontal surface. The TL, DF and TETD values of eight different walls and two different flat roofs commonly used in Turkey are computed utilizing the measured temperature and solar radiation values. The computed values for the TI, DF and TETD are compared with theoretical results obtained numerically using periodic solution of one dimensional transient heat transfer problem for the same structures. (C) 2008 Elsevier Ltd. All rights reserved.
