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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 Artificial neural network approach for theprediction of thermal ınsulation properties of lightweight building materials for energy efficient buildings(İnönü Üniversitesi, 2016) Oktay, Hasan; Polat, Süleyman; Fidan, ŞehmusÖğe Prediction of the thermal conductivity of lightweight building materials utilizing backpropagation neural network method(Fırat Üniversitesi, 2015) Oktay, Hasan; Polat, Süleyman; Fidan, ŞehmusThe growing concern about energy consumption of heating and cooling of buildings has led to a demand for improved thermal performances of building materials. In this study, an experimental investigation is performed to predict the thermal insulation properties of wall and roof structures of which the mechanical properties are known, by using backpropagation artificial neural network (ANNs) method. The produced samples are cement based and have relatively high insulation properties for energy efficient buildings. In this regard, 102 new samples and their compositions are produced and their mechanical and thermal properties are tested in accordance with ASTM and EN standards. Then, comparisons have been made between the determined thermal conductivity of the newly produced structures, which are obtained from experimental method and ANN method that uses mechanical properties as input parameters. From the test results, since the percentage errors in the thermal conductivity values between experimental data and neural network prediction vary from - 1.09% to 6.4%, It can be concluded that the prediction of the artificial neural network has proceed in the correct manner.Öğe Experimental and articial neural network based studies on thermal conductivity of lightweight building materials(European Journal of Technique (EJT), 2017-04-01) Oktay, Hasan; Fidan, Şehmus; Sevim, Davut; Polat, SüleymanThe growing concern about energy consumption of heating and cooling of buildings has led to a demand for improved thermal performances of building materials. In this study, an experimental investigation is performed to predict the thermal insulation properties of wall structures of which the mechanical properties are known; by using Levenberg-Marquardt training algorithm based artificial neural network (ANNs) method for energy efficient buildings. The produced samples are cement based and have relatively high insulation properties for energy efficient buildings. In this regard, 102 new concrete samples and their compositions are produced and their mechanical and thermal properties are tested in accordance with ASTM and EN standards. Then, comparisons have been made between the experimental results and the ANN predicted results. It can be concluded that thermal performance of lightweight materials could be predicted with high accuracy using artificial neural network approach.Öğe 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 Investigation of the thermal and acoustic performance of perlite- based building materials(European Journal of Technique (EJT), 2016-12) Oktay, Hasan; Argunhan, Zeki; Doğmuş, RecepPerlite is a siliceous volcanic glass that provides heat and sound insulation, whose volume can expand substantially under the effect of heat. Perlite ore is one of the most important mineral resources for Turkey where holds a large portion reserves in the world. Evaluation of perlite in building industry, which has advantages in terms of heat and sound insulation, will make an important contribution to the national economy. In this context, experimental investigations are performed for obtaining new concrete types with relatively high strength, low density and good thermal and acoustic properties for energy efficient buildings. For this purpose, 6 sets and different types of concrete samples were prepared with a constant watercement ratio, and normal aggregates replaced by expanded perlite aggregates at different volume fractions such as 10%, 20%, 30%, 40%, 50% and 60% of the total aggregate volume. Mechanical and thermal tests were all conducted and the hot disk method was used to establish thermal property values of concrete samples. The results of the experimental studies show that the compressive strength and density decreases, while highly increases the heat and sound insulation features with increasing in perlite content. As a result, it was found out that the reductions in thermal conductivity [Wm–1K–1] and ultrasonic pulse velocity [km/s] of the produced samples reached to 75% and 35%, respectively.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 Investigation of the thermal performance of high insulation building materials by using light-weight aggregates(Dicle University, 2016) Oktay, Hasan; Argunhan, Zeki; Doğmuş, RecepPerlite is one of the most important mineral resources in Turkey where a large part of world reserves was estimated to be found in. Perlite is a siliceous volcanic glass that provides heat insulation. When it is expanded, it's volume increases about 30 times of the original volume. Despite the fact that Perlite is used in different areas, the most common usage is seen in the construction sector. In this context, experimental investigations are performed for obtaining new concrete types with relatively high strength and good thermal properties for energy efficient buildings. For this purpose, 6 sets and different types of concrete samples were prepared with a constant water-cement ratio, and normal aggregates replaced by expanded perlite aggregates at different volume fractions such as 10%, 20%, 30%, 40%, 50% and 60% of the total aggregate volume. Mechanical tests were all conducted and the hot disk method was used to find thermal conductivity values of concrete samples. As a result of experimental study, it was found out that the reductions in thermal conductivity of the produced samples reached to 75%. As a result, with suitable ratio usage of expanded perlite aggregate was understood to be effective on the mechanical properties and thermal conductivity of perlite aggregated light weight concrete and the relations between the mechanical and thermal properties were determined.Öğe Comparison of thermal performance of newly produced lightweight wall and roof elements for energy-efficient buildings(Hitit Üniversitesi, 2020-03-01) Oktay, Hasan; Yumrutaş, Recep; Argunhan, ZekiIn this study, both experimental and theoretical investigations are performed to obtain new concrete types with high thermal insulating characteristics for energy-efficient buildings. In this regard, 102 new concrete wall samples were produced using different aggregates at different volume fractions, and their thermophysical properties were tested according to EN and ASTM standards. The experimental research focused on developing new wall or roof types with higher thermal insulation properties in order to reduce the energy consumption of buildings due to heating or cooling. In order to specify the thermal performance of developed lightweight concretes, an analytical solution method is developed by the Complex Finite Fourier Transform CFFT method to estimate heat gain utilizing measured thermophysical properties data of those samples. The results indicated that the reduction in heat gain value was obtained as 83.21 % for the PC100 wall corresponding to conventional concrete. Consequently, the thermal insulation effect of those samples shows excellent potential for development.
