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Öğe An exergy analysis of a concentric tube heat exchanger using hBN-water nanofluids(Inder Science Publishers, 2021) Budak Ziyadanoğulları, Neşe; Perçin, SüleymanThis study investigated the effects of using nanofluids prepared with hexagonal boron nitride (hBN) nanoparticles on the thermal performance and pressure drop of a concentric tube heat exchanger. Experiments were carried out with water-hBN nanofluids for stable, dispersed, 0.01%, 0.1% and 1% volume concentrations, at different flow rates and Reynolds numbers under parallel and counter-flow conditions. When the experimental results were examined, the exergy loss was higher in the parallel-flow heat exchanger compared to the counter-flow heat exchanger. The highest exergy loss value was obtained for distilled water at the highest Reynolds number (Re = 8,700) for parallel flow operation at 170 W. The exergy loss of water at the highest Reynolds number (Re = 8,700) for parallel flow operation increased by 15.7%, 24.8% and 49.8% for hBN-water concentrations of 0.01%, 0.1% and 1%, respectively. Exergy loss of water at the highest Reynold number (Re = 8,700) for counter flow operation increased by 11.3%, 17.3% and 29.2% for hBN-water concentrations of 0.01%, 0.1% and 1%, respectively. When evaluating the exergy analysis of the system, exergy losses due to pressure drops were negligible for both flows (parallel and counter).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 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 The experimental study of nanofluids on a flat-plate solar collector(Fırat Üniversitesi, 2017) Budak Ziyadanoğulları, Neşe; Yücel, Halit Lutfi; Yıldız, Cengiz; Işık, Mehmet KemalSolar 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 250 l/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 medium.Öğe Thermal performance enhancement of flat-plate solar collectors by means of three different nanofluids(Elsevier, 2018-12) Budak Ziyadanoğulları, Neşe; Yıldız, Cengiz; Yücel, Halit LutfiSolar energy, which comes first among renewable energy sources, enables efficient use of energy with many applications due to its low operating cost and environmental friendliness. In this study, we experimentally investigated the effects on thermal efficiency of nanofluid and water as working fluids in flat-plate solar collector hot water solar energy systems. Nanofluids were prepared by adding Al2O3, CuO, and TiO2 nanoparticles at 0.2, 0.4, and 0.8 vol% into distilled water, and then the thermophysical properties (thermal conductivity, viscosity) of the prepared nanofluids were determined. Flow rate was adjusted to 250 l/h at given concentrations for each nanofluid in the experimental setups and data such as collector inlet and outlet temperatures, ambient and tap water temperatures; radiation, humidity, and wind speed were measured and recorded. The obtained data were used to calculate efficiencies according to ASHRAE 93-2003 standards. When compared with water, the results indicated that the use of nanofluid increased collector efficiency.Öğe Sample of Batman in determination of urban solid waste management and recycling potential(International Journal of Physical Sciences, 2012-11-16) Adin, Hamit; Oktay, Hasan; Topkaya, Tolga; Işık, Mehmet Zerrakki; Budak Ziyadanoğulları, NeşeThe collection, transport, treatment, and disposal of solid wastes, particularly wastes generated in medium and large urban centres, have become a relatively difficult problem to solve for those responsible for their management. However, recycling-related activities bring waste reduction, prevention of waste of raw materials and less environmental damage as well as providing an economic benefit to the countries. In this paper, a case study of a developing country has been examined dealing with serious pollution problems due to the ineffective management of the large solid waste generated in the city of Batman in Turkey. The aim of this paper is to estimate the quantity of waste produced that requires collection and the different waste constituents, to analyze the current practices of SWM, to propose an environmentally sound and economically feasible integrated management system for dealing with solid waste. Results showed that the average generation rate of MSW was 0.75 kg/capita/day in Batman and also, it has been anticipated that the wastes could be disposed by using modern methods instead of irregular storageÖğe Boron usage and advantages in energy applications(Batman Üniversitesi, 2018) Budak Ziyadanoğulları, Neşe; Perçin, SüleymanÖğe New generation solar batteries: biophotovoltaics(Dicle University, 2019) Budak Ziyadanoğulları, Neşe; Özdemir, YunusIn this review study, the applications of plants to obtain energy from the electron flow formed as a result of photosynthesis reaction were investigated. Biophotovoltaic (BPV) devices are biological solar cells that convert the energy released into electrical energy by microorganisms such as algae. A series of reactions occurs when the solar radiation falls on the alga. Water is divided into three parts: proton (H + ion), electron and oxygen. These ions and the element of oxygen are vital for the inorganic substances contained in carbohydrates and proteins, which allow the growth of alga. Electricity is produced when the sensor is placed in a system containing two electrodes separated by a membrane that allows only protons to pass through. Electrons produced during photosynthesis pass through an external circuit to water form and reunite with proton and oxygen at the reductive electrode (cathode). Electricity is generated as a result of flow passing through the external circuit and can be used to operate electronic devices.Öğe Effects of nanofluids on the efficiency of a flat plate solar collector(Fırat Üniversitesi, 2015) Budak Ziyadanoğulları, Neşe; Yıldız, Cengiz; Yücel, Halit LutfiÖğe 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.
