Yazar "Yildirim, Cihan" seçeneğine göre listele

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    A parametric study on a humidification-dehumidification (HDH) desalination unit powered by solar air and water heaters
    (Pergamon-Elsevier Science Ltd, 2014) Yildirim, Cihan; Solmus, Ismail
    The performance of a solar powered humidification-dehumidification desalination system is theoretically investigated for various operating and design parameters of the system under climatological conditions of Antalya, Turkey. The primary components of the system are a flat plate solar water heater, a flat plate double pass solar air heater, a humidifier, a dehumidifier and a storage tank. The mathematical model of the system is developed and governing conservation equations are numerically solved by using the Fourth order Runge-Kutta method. Daily and annual yields are calculated for different configurations of the system such as only water heating, only air heating and water-air heating. (C) 2014 Elsevier Ltd. All rights reserved.
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    Artificial bee colony algorithm for thermohydraulic optimization of flat plate solar air heaters
    (Korean Soc Mechanical Engineers, 2017) Yildirim, Cihan; Aydogdu, Ibrahim
    Determination of thermal efficiency is not a sufficient tool for solar air heaters because of disregarded energy consumption by fans. Most of the solar air heaters are equipped with fans in order to overcome pressure drops. Thermohydraulic efficiency is more favorable than thermal efficiency in terms of the design of solar energy conversion systems. In this present study, Artificial bee colony (ABC) based optimum design and operation algorithm is developed for Single pass solar air heater (SPSAH) and for Double parallel pass solar air heater (DPPSAH) which maximizes thermohydraulic efficiency. In order to solve the algorithm, channel depth is treated as a design variable, and air mass flow rate is defined as an operation parameter. Furthermore, energy balance equations are written for solar air heaters and solved for steady-state condition. As a result, optimum design and operation values are obtained from the algorithm for different collector lengths and solar insolation levels.
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    Experimental investigation of a portable desalination unit configured by a thermoelectric cooler
    (Pergamon-Elsevier Science Ltd, 2014) Yildirim, Cihan; Soylu, Sezgi Kocak; Atmaca, Ibrahim; Solmus, Ismail
    Possible use of a novel portable desalination system was investigated experimentally. The system is based on humidification-dehumidification principle add thermoelectric cooling technique. A thermoelectric cooler was integrated into the system to enhance the process of both humidification and dehumidification. A prototype was fabricated and its performance was tested for various working conditions of the prototype to observe complex relation between psychrometric and thermoelectric phenomena. The effect of feed water mass flow rate and air flow velocity on the COP value of the thermoelectric cooler and clean water production of the system were examined. The maximum daily yield of the system and the COP value of the thermoelectric cooler unit were recorded as 143.6 g and 0.78, respectively. (c) 2014 Elsevier Ltd. All rights reserved.
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    How May New Energy Investments Change the Sustainability of the Turkish Industrial Sector?
    (Mdpi, 2023) Yildizhan, Hasan; Yildirim, Cihan; Gorjian, Shiva; Ameen, Arman
    Utilization of renewable energy in the Turkish industrial sector is becoming more important nowadays. The tendency toward renewable energy can be clearly seen with newly planned energy investments. The energy appearance of the Turkish industrial sector for past two decades and ongoing energy projects are discussed in this study with the help of sustainability indicators. The sustainability index is based on advanced exergy analysis and shows the environmental impact of production processes and measures the transformation of energy resources in the Turkish industrial sector. This index was approximately 2.03 in 2000 and it improved to 2.25 in 2008, and then remained constant with minor fluctuations until 2019. Depending on the fulfillment of the continuing fossil, nuclear, and recommended renewable energy investment scenarios, the sustainability index may change to between 1.96 and 2.17 by 2023. None of the ongoing investments will make a major improvement in the sustainability of the industrial sector; therefore, a major shift toward the use of more renewable energy is urgently needed. Establishing solar or wind energy microgrids plants may improve the sustainability indicators drastically, therefore, encouragement of their investments is very important.
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    Investigating the Effect of Weight Reduction of Rod-End in Drag-Link Product with Finite Element Analysis, Fatigue Test, and a Case Study
    (Korean Soc Automotive Engineers-Ksae, 2020) Uludamar, Erinc; Tas, Mustafa; Bicer, Sami Gokberk; Yildirim, Cihan; Yildirim, Ebru Aykut; Celebi, Kerimcan
    The connection surfaces of drag-link must be tough and safe enough to carry transmitted forces that exert on the product in service conditions. Therefore, undulated forming takes place in machining process to stay the rod-ends in the rod. In the rod-end, after forming process, a straight part which remains on the body causes extra cost and weight on the product. In this study, the result of shortening of rod-end which was produced from C45+N quality steel was investigated by comparing with the unmodified rod-end. The comparison was carried out by fatigue test and Finite Element Analysis. The results showed that the cropped part has almost no effect on the durability of the product. It is measured that the modification result with 0,082 kg weight reduction on each rod-end and 5 seconds shortening of machining process were observed by the modification on rod-end. The effect of modification on the part was examined in a case study. The case study indicated that annual expenses of raw material lowered by $9.124,56 and total cost decreased by $11.480,20.
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    The Drivers and Barriers of the Solar Water Heating Entrepreneurial System: A Cost-Benefit Analysis
    (Mdpi, 2023) Yilmaz, Sidika Ece; Yildizhan, Hasan; Yildirim, Cihan; Zhao, Chuang-Yao; Gomes, Joao; Alkharusi, Tarik
    Sustainable development objectives place a high priority on entrepreneurship and renewable energy. Supporting entrepreneurial activities in the renewable energy industry can provide economic growth and employment to accomplish the Sustainable Development Goals Agenda 2030. Solar water heating systems can provide clear benefits for both the environment and economic growth. There is a gap in the literature regarding the study of the factors hindering or driving the development of the solar water heating system industry. This study aims to investigate the solar water heating system industry's challenges and attempts to define the drivers to further develop the industry. Thus, solar water heating entrepreneurship parameters can be identified. Additionally, energy savings and carbon dioxide emissions were calculated for the region to raise awareness among consumers. This study used the qualitative analysis method through semi-structured interviews with 40 business owners in Adana/Turkey. The findings showed that the industry has administrative, production, political, and economic issues; there is a need for economic support and expanding education and control mechanisms. Also, the payback period is 1.63 similar to 3.27 years for a solar water heating system and this system prevents 800.75 kg of CO2 emission. The study has implications for policy-making, practice, scientific research, and the SDGs Agenda 2030.
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    Transient behavior of a cylindrical adsorbent bed during the adsorption process
    (Elsevier Sci Ltd, 2015) Solmus, Ismail; Yamali, Cemil; Yildirim, Cihan; Bilen, Kadir
    A transient two dimensional local thermal non-equilibrium model is developed to investigate the influences of heat transfer and operating parameters on the dynamic behavior of a cylindrical adsorbent bed during the adsorption process. Local volume averaging method is used to drive the macro scale governing conservation equations from the micro scale ones. In the model, linear driving force model and Darcy's equation are considered to account for the resistances to internal and external mass transfer, respectively. Silica gel-water pair widely used in the adsorption cooling systems is chosen to be an adsorbent-adsorbate working pair. The parameters of interest are convective heat transfer coefficient, solid phase thermal conductivity, bed thickness, evaporator pressure, condenser pressure, driving heat source temperature and cooling source temperature. It is found that amount of refrigerant circulated through the system increases with increasing evaporator pressure-driving heat source temperature and decreasing condenser pressure-cooling source temperature. The duration of adsorption process is more sensitive to heat transfer resistances than to mass transfer resistances. The conductive and convective resistances need to be reduced to reach the equilibrium conditions in a short period of time and hence to have a better specific cooling power. (C) 2015 Elsevier Ltd. All rights reserved.