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Öğe An experimental investigation of the effect of thermophysical properties on time lag and decrement factor for building elements(Gazi University, 2020-06-01) Oktay, Hasan; Yumrutaş, Recep; Argunhan, ZekiThe time lag (TL) and decrement factor (DF) are essential for the heat storage capabilities of building elements, which strictly depend on the thermophysical properties of the elements. Many investigations are presented in literature arguing to find the influence of each thermophysical property on TL and DF by keeping the other properties constant. This study aims to investigate the effect of each property on TL and DF, utilizing relationships between the measurement values of the thermophysical properties of wall materials. Therefore, first, 132 new concrete wall samples were produced, and their thermophysical properties were tested. Secondly, TL and DF values for each building element are computed from the solution of the problem by Complex Finite Fourier Transform (CFFT) technique. Finally, a multivariate regression analysis has been performed, and the variations of each thermophysical property versus TL and DF are presented, and also the findings are compared with literature. The results show that each property alone (keeping the other properties constant) is not adequate to identify the thermal inertia and thermal performance of a wall element. Besides, 87.3 % decrease in thermal diffusivity corresponds to 6.03 h increase in the value of TL and 88.8 % decrease in value of DF; respectively, for W1 wall assembly.Öğe Experimental investigation of the effects of diesel-like fuel obtained from waste lubrication oil on engine performance and exhaust emission(Journals & Books, 2010-10) Argunhan, Zeki; Yumrutaş, Recep; Arpa, OrhanIn 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.Öğe Comparison of CLTD and TETD cooling load calculation methods for different building envelopes(Mugla Sitki Kocman University, 2020-06-30) Oktay, Hasan; Yumrutaş, Recep; Işık, Mehmet ZerrakkiThe estimation of the cooling load through the building envelope is an essential task in the selection of proper HVAC system components that influences the building’s performance. For this task, ASHRAE has presented several methods to calculate the building cooling load due to heat gain, such as the total equivalent temperature difference method (TETD), the cooling load temperature difference method (CLTD), and the radiant time series method (RTS). The present study aims to explore the accuracies of those calculation methods in terms of energy efficiency. In this regard, an analytical solution method utilizing Complex Finite Fourier Transform Technique (CFFT) was developed for the calculation of cooling load due to heat gain to compare the temperature differences obtained from the TETD and CLTD methods. Then, a computer program was prepared in MATLAB to perform the calculations based on an analytical methodology. Besides, the estimated CLTD and TETD values by the CFFT were compared with those values presented in the Handbook of the ASHRAE. The calculation results revealed there is a good agreement between the analytical and presented results in the ASHRAE Manual for the selected building envelopes. However, several differences were found between the estimated TETD and CLTD cooling load values and those presented in the Handbook of ASHRAEÖğe Comparison of the thermal performances of concretes containing waste rubber for energy efficient buildings(2018) Oktay, Hasan; Yumrutaş, RecepDue to the rapid depletion of available sites, the disposal of waste tires is becoming a serious environmental problem day by day. Assessment of waste rubbers in concrete is an innovative solution that meets both the challenge of the tire disposal problem and a demand for improved thermal performances of structural materials for energy efficient buildings. Therefore, in this study, an investigation is performed both to obtain new concrete types by using waste rubbers with high thermal insulating characteristics and to compare the thermal performance of those concretes with conventional ones. For this purpose, different types of concrete samples were prepared with a constant water-cement ratio, and normal aggregates replaced by rubber aggregates at different volume fractions between 0% and 60% of the total aggregate volume. In the experiments, all mechanical tests were conducted and the hot disk method was used to establish thermal property values of concrete samples. In order to determine the most suitable concrete samples, heat flows through the produced samples are calculated using a program developed in MATLAB. Calculation method for the heat flow is based on solution of transient heat transfer problem for the multilayer structures. The program is executed to calculate hourly heat gain values for these samples over a period of 24 h during design day for Batman, Turkey. The results indicated that the maximum reduction in heat gain value was obtained as 50.6 % for RC60 wall with commonly used thickness of 20 cm corresponding to conventional concrete.Öğe An investigation of the influence of thermophysical properties of multilayer walls and roofs on the dynamic thermal characteristics(Mugla Sitki Kocman University, 2016-06-09) Oktay, Hasan; Argunhan, Zeki; Yumrutaş, Recep; Işık, Mehmet Zerrakki; Budak Ziyadanoğulları, NeşeThe growing concern about energy consumption of heating and cooling of buildings has led to a demand for improved thermal performances of building materials. To achieve this goal, in this study, an investigation is performed to analyze the influence of thermophysical properties and thickness of various multilayer building walls or roofs in a building on the dynamic thermal characteristics, such as the decrement factor (DF), time lag (TL) and heat gain. In order to find the thermal performance characteristics of building structures, such as briquette, brick, blockbims and autoclaved aerated concrete (AAC), which are commonly used in Turkey, an analytical solution method was developed in a computer program in MATLAB and results are compared to determine suitable wall or roof material. Calculation method for the heat flow is based on solution of transient heat transfer problem for the multilayer structures. The program is executed to calculate hourly heat gain values for these samples over a period of 24 h during design day for Gaziantep, Turkey. It was found that thermophysical properties of roofs or walls have a very profound effect on the time lag (TL), decrement factor (DF) and also heat gain.Öğe Effects of fuels produced from fish and cooking oils on performance and emissions of a diesel engine(Elsevier, 2014-07-15) Oktay, Hasan; Yumrutaş, Recep; Behçet, RasimIn this study, two fuels called as FOME (Fish Oil Methyl Ester) and COME (Cooking Oil Methyl Ester) were produced from waste fish and cooking oils using the transesterification method. Commercial D2 (Diesel fuel) and two fuel samples obtained by blending the FOME and COME with the D2 with a ratio of 25% on volume basis were used as fuels in a Diesel test engine. An experimental study was performed for investigating the performance and exhaust emissions of the Diesel engine using the fuels. According to the test results, it was observed that the fish oil based fuel indicated better performance and exhaust emission parameters than those of cooking oil. Results clearly showed that the engine power and torque values were lower than those of the Diesel fuel with values of 3.05% and 1.25% for FB25, and 4.07% and 2.2% for CB25, respectively. Also, brake specific fuel consumption for the produced fuels increased up to 5.69% compared to Diesel fuel. However, HC and CO emission reductions compared to the Diesel fuel were found to be around 16.24% and 19.81%, respectively. But, the amount of increase in NOx emissions for the same biodiesel fuels reached up to 17.2%.Öğe Comparison of heat gain values obtained for building structures with real and constant properties(Bitlis Eren Üniversitesi, 2019-12-24) Oktay, Hasan; Yumrutaş, Recep; Argunhan, ZekiThe magnitude of energy consumption due to the heating and cooling of buildings has led to the demand for increasing the thermal performance of building structures. Many investigations are presented in literature arguing to find the effect of each thermophysical property on the thermal characteristics of building components, while the properties have been assumed as independent of each other. In this context, this paper focuses on the effect of each property on heat gain value utilizing relationships between the measurement values of the thermophysical properties of building structures. In the previous study, 102 new wall samples were produced, their thermophysical properties were tested and expressions among these properties are obtained. In this study, the heat gain values through the structures are computed using the solution of the transient heat transfer problem by using both the obtained expressions between the thermophysical properties and assumptions proposed from the literature. Results obtained for varying and constant thermophysical properties have been compared with those values presented in the literature. The results show that the assumptions are not realistic in a significant number of cases. Moreover, if one of the thermophysical properties of a material is known, heat gain values can be calculated easily for the selected wall or roof types.Öğe Bina duvarlarının termofiziksel özellikleri arasındaki ilişkilerin kullanılarak bu özelliklerin ısı kazancına olan etkisinin incelenmesi(Fırat Akademi A.Ş, 2017) Oktay, Hasan; Yumrutaş, Recep; Argunhan, Zeki; Işık, Mehmet ZerrakkiBinaların ısıtılması ve soğutulması için tüketilen enerjinin gün geçtikçe artması ısıl performansı yüksek olan inşaat malzemelerinin geliştirilmesine ihtiyaç duyulmuştur. Malzemelerin ısıl performansı ise direk olarak bu malzemelerin termofiziksel özelliklerine bağlıdır. Her ne kadar literatürde termofiziksel özelliklerin ısıl performans kriterleri olan ısı kazanç, zaman kayması gibi dinamik ısıl karakterlerine olan etkileri incelense de, bu özelliklerin birbiri arasındaki ilişkiler göz ardı edilmiştir. Bu amaçla; her bir termofiziksel özelliğin ısı kazancına olan etkisini incelemek için bir çalışma gerçekleştirilmiştir. Farklı bileşimli 102 beton duvar numunesi üretilerek, termofiziksel özellikleri ASTM ve EN standartlarına göre ölçülmüş ve aralarındaki ilişkiler yeni ifadelerle tanımlanmışır. Daha sonra bu ilişkiler kullanılarak, Gaziantep’ te sıcak bir günde herhangi duvar ve tavanda oluşan ısı kazancını hesaplamak amacıyla kompleks Fourier dönüşüm tekniği (CFFT) kullanılarak MATLAB tabanlı bir bilgisayar programı hazırlanmış ve elde edilen sonuçlar irdelenmiştir. Sonuç olarak, bu yapılan çalışma sayesinde herhangi bir termofiziksel özelliği belli olan duvarların ısı kazançları kolaylıkla hesaplanabilmektedir.Öğe Duvarlarının termofiziksel özellikleri arasındaki ilişkileri ile bu özelliklerin dinamik ısıl karakterlerine etkilerinin araştırılması(Süleyman Demirel Üniversitesi, 2018-08-15) Oktay, Hasan; Yumrutaş, Recep; Yıldırım, MurtazaBinaların ısıtılması ve soğutulması için tüketilen enerjinin artmasıyla birlikte ısıl performansı yüksek olan inşaat malzemelerinin geliştirilmesine ihtiyaç duyulmuştur. Bu malzemelerin ısıl performansı ise doğrudan termofiziksel özelliklere bağlı olarak değişmektedir. Her ne kadar literatürde her bir termofiziksel özelliğin dinamik ısıl karakterleri olan; faz kayması (TL) ve sönüm oranına (DF) etkisi incelense de, bu özelliklerin birbiri arasındaki ilişkiler göz ardı edilmiştir. Bu çalışmada ise; her bir termofiziksel özelliğin arasındaki ilişki deneysel yöntemler ile elde edilerek, bu özelliklerin DF ve TL üzerindeki etkileri gerçekçi olarak incelenmiştir. Bu yüzden farklı bileşimli 102 beton duvar numunesi üretilerek, termofiziksel özellikleri ASTM ve EN standartlarına göre ölçülmüş ve aralarındaki ilişkiler denklemlerle tanımlanmıştır. Termofiziksel özelliklerin yapıların ısıl karakterlere olan etkisini incelemek amacıyla, analitik çözüm kullanılarak MATLAB tabanlı bir bilgisayar program hazırlanmış ve elde edilen sonuçlar irdelenmiştir. Sonuç olarak, bu yapılan çalışma sayesinde herhangi bir termofiziksel özelliği belli olan bir bina duvar veya tavan malzemelerinin TL ve DF değerleri kolaylıkla bulunabilmektedirÖğe Mechanical and thermophysical properties of lightweight aggregate concretes(Elsevier, 2015-10-15) Oktay, Hasan; Yumrutaş, Recep; Akpolat, AbdullahIn this study, experimental investigation is performed for producing new cement-based with relatively high strength, low density and good thermal properties for energy efficient buildings. Different types of concretes containing silica fume (SF), superplasticizer (SP) and air-entrained admixtures are prepared with a constant water–cement ratio, and normal aggregates replaced by lightweight aggregates (LWAs) including pumice (PA), expanded perlite (EPA) and rubber aggregates (RA) at different volume fractions of 10%, 20%, 30%, 40% and 50%. 102 samples with different materials and compositions are produced, and their characteristics are tested in accordance with ASTM and EN standards. Based on the experimental results, equations are presented to determine the relation between the thermophysical properties of composite samples. The investigation revealed that the addition of PA, EPA and RA reduced the material bulk density and compressive strength, and improved the insulation characteristics of the composite concretes. Furthermore, it was found out that the reductions in thermal conductivity and diffusivity of the produced samples reached to 82% and 74%, respectively.
