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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 Çok katmanlı duvar ve çatı tiplerinin ısıl ve fiziksel özelliklerinin dinamik ısıl karakterlerine olan etkisinin incelenmesi(Muğla Sıtkı Koçman Üniversitesi, 2015) Oktay, Hasan; Budak Ziyadanoğulları, Neşe; Argunhan, Zeki; Yumrutaş, Recep; Işık, Mehmet ZerrakkiÖğe Combustion, performance and emissions of a diesel power generator fueled with biodiesel-kerosene and biodiesel-kerosene-diesel blends(Elsevier, 2017-02-05) Bayındır, Hasan; Işık, Mehmet Zerrakki; Argunhan, Zeki; Yücel, Halit Lütfi; Aydın, HüseyinHigh percentages of biodiesel blends or neat biodiesel cannot be used in diesel engines due to high density and viscosity, and poor atomization properties that lead to some engine operational problems. Biodiesel was produced from canola oil by transesterification process. Test fuels were prepared by blending 80% of the biodiesel with 20% of kerosene (B80&K20) and 80% of the biodiesel with 10% of kerosene and 10% diesel fuel (B80&K10&D10). Fuels were used in a 4 cylinders diesel engine that was loaded with a generator. Combustion, performance and emission characteristics of the blend fuels and D2 in the diesel engine for certain loads of 3.6, 7.2 and 10.8 kW output power and 1500 rpm constant engine speed were experimented and deeply analyzed. It was found that kerosene contained blends had quite similar combustion characteristics with those of D2. Mass fuel consumption and Bscf were slightly increased for blend fuels. HC emissions slightly increased while NOx emissions considerably reduced for blends. It was resulted that high percentages of biodiesel can be a potential substitute for diesel fuel provided that it is used as blending fuel with certain amounts of kerosene.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 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.Öğe Dairesel kesitli bir borunun girişine yerleştirilen delikli sabit kanatçıklı dönme üreticinin ısı geçişi ve basınç düşüşüne etkileri(Pamukkale Üniversitesi, 2006-02-01) Argunhan, Zeki; Yıldız, CengizBu çalışmada iç içe borulu ısı değiştirgecinde farklı delik sayılı dönme üreticilerin ısı transferine ve basınç düşüşüne etkisi deneysel olarak araştırılmıştır. Bu amaçla değiştirgecin 60 mm çapındaki iç borunun girişine 55º kanat açısına sahip ve kanatlarında birer, ikişer, üçer ve dörder adet dairesel delikler bulunan dönme üreticiler yerleştirilerek deneyler yapılmıştır. Bunlar iç borunun girişine rahat takılıp sökülebilecek şekilde dizayn edilmişlerdir. İç borunun içinden sıcak akışkan olarak hava, iç borunun dışından ise soğuk akışkan olarak su geçmektedir.Öğe Design of solar cathodic protection system in Batman(Kilis 7 Aralık Üniversitesi, 2016) Argunhan, Zeki; Reşitoğlu, Mehmet SelimÖğe Dikdörtgen delikli türbülatörlerde delik sayısının ısı geçişine ve basınç düşüşüne etkisi(Fırat Üniversitesi, 2006) Argunhan, Zeki; Yıldız, CengizBu çalışmada iç içe borulu ısı değiştirgecinde boru girişine yerleştirilen türbülatörlerin (girdap tip akış üreticilerinin) ısı geçişine ve basınç düşüşüne etkisi deneysel olarak araştırılmıştır. Bu amaçla iç içe borulu ısı değiştirgecinin 60 mm çapındaki iç borunun girişine 55º açılı kanatlara sahip ve kanatlarında 2x7 mm ebadında düzgün sıralanmış birer, ikişer, üçer, dörder ve beşer adet dikdörtgen geometrili delikler bulunan türbülatörler yerleştirilerek, bu türbülatörlerin ısı geçişine ve basınç düşüşüne etkileri araştırılmak üzere deneyler yapılmıştır. İç borunun içinde sıcak akışkan olarak hava, dışında ise soğuk akışkan olarak su geçmektedir. Kullanılan türbülatörlerle aynı yönlü paralel ve zıt yönlü paralel akışta deneyler yapılmıştır.Öğe Dimension and insulation thickness optimization of circular flat plate solar collectors(Energy Education Science and Technology, 2011) Argunhan, ZekiIn this study, expressions for optimum radius of a circular flat plate solar collector and the optimum insulation thickness distribution are derived by using the concept of solar gain, which maximizes the life-cycle savings. For the specified condition the optimum radius has been found as 2.14 m and the optimum insulation thickness distribution on back of collectors has been formulized. The insulation material thickness distribution has been determined by performing a detailed dimensional analysis; therefore heat loss is minimized, and results are presented in graphics.Öğe The effect of rotary type turbulator placed in entrance of heat exchanger on heat transfer and frictional loss(Energy Education Science and Technology, 2011) Argunhan, Zeki; Behçet, Rasim; Yakut, Ali KemalIn this study, improving heat transfer in heat exchangers with paralel flow is gained by using swirl flow. For this purpose, a propeller type of turbulator was placed in the entrance of interior pipe of heat exchanger with paralel flow and the effect of turbulator on the heat transfer and friction losses in steady conditions was experimentally investigated. The effect of production of turbulance for improvement of heat transfer in interior pipe flows and the effects of turbulator on heat transfer and pressure drop are experimentally researched by placing a propeller type of turbulator at the entrance of heat exchanger to produce swirl air flow. In experiment setup, water was used as the fluid on which the heat was transferred and air was used as the fluid from which heat was transferred to the water. By usage of datas obtained from experimental measurements were calculated for Reynolds number ranging from 8000 to 24000 necessary relationships effet on heat transfer and pressure drop. In comparison with empty pipe it was seen that the heat transfer increased at range between 25,5%- 50,3% and the friction losses increased 5 times. Besides, by analyzing the system exergy, the dependence of non-dimensional exergy loss on Reynolds number was drawn to investigate whether this improvement technique is advantageous thermodynamically or not. When comparing the exergy losses in empty pipe and the pipe with a turbulator at approximately same Reynolds numbers, it was seen that exergy loss is 15% higher for empty pipe than that for the pipe with the turbulator. As a result of that information, the improvement technique was proved to be advantageous in thermodynamic manner too. By the usage of turbulator that results in the partial recovery of loss energy, it was proven that the improvement technique was thermodynamically advantageousÖğe Effect of swirl generators with different sized propeller on heat transfer enhancement(Energy Education Science and Technology, 2011) Argunhan, Zeki; Yıldız, Cengiz; Çakmak, GülşahIn this study, the swirl flow that is one of the passive methods is used for increasing the heat transfer coefficient in the concentric heat exchangers. For this purpose, propeller type swirl generators were prepared to test in the experiments. So, the effect of propellers placed in the inner pipe of the concentric heat exchangers on the heat transfer and pressure drop was investigated experimentally. Experiments were undertaken for the Reynolds Number range of 4000-12000 and for both parallel and counter-flow. It is shown that, the propellers rotated freely with the effect of fluid flowed in the inner pipe are swirling flow generator and they have improved heat transfer. In addition that up to 50% enhancements could be accomplished in heat transfer rates with the swirl generators compared to without the swirl generators. In the parallel flow mode, the enhancement was 10% lower than that of counter-flow at the same Reynolds number. On the other hand the pressure losses increase approximately 3 times more than the empty tube related to Reynolds numbers and propeller sizes. As an outcome of the study, the results showed that a rather smaller size but the same capacity heat exchanger could be proposed by using these elements imposing swirling to the fluid flowing through inner pipe.Öğe Effect of the air flow rate of blower on the performance of solar still(Türk Isı Bilimi ve Tekniği Derneği, 2015-06-01) Argunhan, Zeki; El, Emin; Yücel, Halit Lutfi; Çakmak, Gülşah; Yıldız, CengizSolar distillation is one of the important methods for water purification. This paper examines the performance of solar distillation system at different air flow rate. To increase the performance of distiller, artificial wind was created by fan and suitable wind speed was investigated to increase the amount of water distilled. The experiments were carried out in Elazığ climate conditions. In order to examine the effect of the wind speed on solar distillation system, two stills were manufactured with the size of 1000x1000 mm. One of them was the conventional still which was used as a reference. The other still was used to investigate experimentally the effect of the wind speed. Graphs were drawn for time-dependent changes in the amount of water distilled. It was found that that the productivity of the fan-still distiller was 14.7 % greater than that of a conventional still.Öğe The efficiency of Al2O3 water nanofluid on a flat plate solar collector(SETCOR publications, 2015) Budak Ziyadanoğulları, Neşe; Yıldız, Cengiz; Argunhan, Zeki; Tekalp, Selen; Yücel, Halit LutfiSolar collectors are particular kind of heat exchangers that transform solar radiation energy into internal energy of the transport medium. One of the most effective methods is replacing the working fluid (water, ethylene glycol, engine oil…) by developing a new class of fluids with a higher thermal conductivity for thermal systems. In the present work the effect of Al2O3-water, as working fluid, on the efficiency of a flat plate solar collector is investigated experimentally. The mass flow rate of nanofluid is 150 Lit/h. The volume fraction of the nanoparticles is 0.2 %, 0.4 % and 0.8 % respectively. The results reveal the impact and importance of each of these parameters. Experimental results reveal that utilizing the nanofluid increases the collector efficiency in comparison to water as an absorbing mediumÖğe Estimation of thermal performances of newly produced lightweight walls for energy efficient buildings(Kilis 7 Aralık Üniversitesi, 2016) Oktay, Hasan; Yumrutaş, Recep; Argunhan, Zeki; Ayanoğlu, AbdulkadirÖğe Evaluation of fly ash and polypropylene in production of composite materials(Energy Education Science and Technology, 2012) Argunhan, Zeki; Yıldız, Tülay; Haksever, AysenMore than 10 million tons of fly ash produced in power plants and polypropylene wastes cause environmental pollution in Turkey. Not only the environmental problems they create, but also the fact that demand for raw material sources increases rapidly make fly ashes and waste polypropylene necessary to be researched. In this study the usability of the fly ashes and polypropylene wastes of Soma and Afsin-Elbistan Power Plants in producing new composite materials has been investigated. Materials which possess new properties such as composite type isolation have been formed by melting down the polypropylene wastes that are used as combining elements and by mixing this with fly ash in different percentages. The thermal conductivity, endurance against pressure pull-corrosion, and the rates of water absorption of these materials were analyzed experimentally and both stated and interpreted in the graphics. By this way, these two materials can be recovered by both lessening the environmental problems and providing income for economy by means of saving energy.Öğe Experimental and numerical investigation of the effect of turbulator on heat transfer in a concentric-type heat exchanger(Taylor & Francis, 2015-05-21) Budak Ziyadanoğulları, Neşe; Argunhan, Zeki; Yücel, Halit LutfiThis article experimentally and numerically analyzes the effect of turbulators with different geometries (Type I, Type II, Type III, and Type IV) located at the inlet of the inner pipe in a concentric-type heat exchanger. Experiments were performed at parallel-flow conditions in the same and opposite directions to investigate the impact of manufactured turbulators on heat transfer and pressure drop. In the numerical study, ANSYS 12.0 Fluent code program was used, and basic protection equations were solved in the steady-state, three-dimensional, and turbulence-flow conditions. Results were obtained from numerical analysis conducted at different flow values of air (7, 8, 9, 10, 11, and 12 m3 /h). The distribution of temperature, velocity, and pressure was demonstrated as a result of numerical analyses. Experimental and numerical results were compared, and it was observed that they were in conformity with each other. When the data obtained from the analyses were examined, the highest heat transfer, pressure drop, and friction factor increase were detected to be in the Type IV turbulator.Öğe Experimental investigation of solar stills integrated with solar water heating collectors(Türk Isı Bilimi ve Tekniği Derneği, 2017-10-31) Argunhan, Zeki; El, Emin; Yıldız, Cengiz; Çakmak, GülşahSolar still is a more practical way of obtaining clean water. In this study, we aimed to improve the efficiency of solar still systems and obtain distilled water at the same time. For this purpose, 5 different solar still systems were designed. Type 1; conventional solar still, Type 2; conventional solar still integrated with solar water heating collector and run via natural convection, Type 3; conventional solar still integrated with solar water heating collector and tubular heat exchanger and run via natural convection, Type 4; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via natural convection, Type 5; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via forced convection. In this study, the experiments were carried out on the parameters influencing the performance, the amount of distilled water obtained, and the efficiency of experiment settings designed in different types; and finally the results were presented. The amount of distilled water and efficiency of conventional solar still were 2389 ml and 51.47%, respectively. Maximum total amount of water and efficiency from natural convection systems were obtained from Type 4, and the values calculated were found as to be 5788 ml and 55.91%. Maximum amount of distilled water and the efficiency were obtained by utilizing forced convection system were found as to be 6068 ml and 58.99%, respectively.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 Experimental investigation of thermal performance in a concentric tube heat exchanger with wavy inner pipe(SpringerLink, 2012-06) Argunhan, Zeki; Çakmak, Gülşah; Yücel, Halit Lutfi; Yıldız, CengizIn this article, the heat transfer, friction factor, and thermal performance factor characteristics of a concentric-tube heat exchanger are examined experimentally. A wavy inner pipe is mounted in the tube with the purpose of generating swirl flow that would help to increase the heat transfer rate of the tube. The examination is performed for a Reynolds number ranging from 2700 to 8800. An empirical correlation is also formulated to match with experimental data of the Nusselt number using the Wilson plot method. In addition, to obtain the real benefits in using the swirl generator at a constant pumping power, the thermal enhancement factor is also determined. Over the range considered, the increases in the Nusselt number, friction factor, and thermal performance factor are found to be, respectively, about 113 %, 81 %, and 196 % higher than those obtained from a smooth-surface inner pipe.
