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Bilecik, Turkey

Acikkalp E.,Bilecik University
International Journal of Electrical Power and Energy Systems

In this study, thermodynamic optimization criteria used for assessing thermal engines are investigated and compared. The Purpose of this is to determine the most advantageous criteria. An irreversible Carnot cycle is analyzed by using five different methods and results are compared. According to calculations, the ecological function criterion (ECF) is defined as the most convenient optimization method. Although, its work output is less than the maximum work criteria and maximum available work (MAW), it has advantageous in terms of entropy generation and first law efficiency. In addition, ecological coefficient of performance (ECOP) and exergetic performance criteria (EPC) values provide minimum entropy generation and maximum efficiency at their maximum, however, their work output is very small. ECF obtains its maximum values at x = 0.488 (377.175 kW) for endoreversible cycle and at x = 0.477 (329.812 kW) for irreversible cycle. For these reasons, ECF is suggested as the best optimization criteria. © 2015 Elsevier B.V. All rights reserved. Source

Acikkalp E.,Bilecik University
Physica A: Statistical Mechanics and its Applications

Purpose of this paper is to assess irreversible refrigeration cycle by using exergetic sustainability index. In literature, there is no application of exergetic sustainability index for the refrigerators and, indeed, this index has not been derived for refrigerators. In this study, exergetic sustainability indicator is presented for the refrigeration cycle and its relationships with other thermodynamics parameters including COP, exergy efficiency, cooling load, exergy destruction, ecological function and work input are investigated. Calculations are conducted for endoreversible and reversible cycles and then results obtained from the ecological function are compared. It is found that exergy efficiency, exergetic sustainable index reduce 47.595% and 59.689% and rising at the COP is 99.888% is obtained for endoreversible cycle. Similarly, exergy efficiency and exergetic sustainability index reduce 90.163% and 93.711% and rising of the COP is equal to 99.362%. © 2015 Elsevier B.V. All rights reserved. Source

Ac ikkalp E.,Bilecik University | Caner N.,Eskiehir Osmangazi University
Physica A: Statistical Mechanics and its Applications

In last decades, nano technology developed. Since, nano scale thermal cycles will be possibly used in near future. In this study, a nano scale irreversible dual cycle was analyzed thermodynamically. Ideal Maxwell-Boltzmann gas is used for working fluid in the system. He4 is chosen as working fluid. Results are obtained as numerically. In calculations, different thermodynamic performance evaluation methods are applied and these methods are compared each other to determine the most convenient optimization way. © 2015 Elsevier B.V. All rights reserved. Source

Akyuz B.,Bilecik University
Transactions of Nonferrous Metals Society of China (English Edition)

Influence of Al content on the machinability of AZ series cast Mg alloys was investigated. In order to evaluate the machinability of the alloys, measurements of the cutting forces during turning operations and surface roughness were carried out as well as considering the microstructure and tensile properties. The results show that maximum tensile properties are observed with 2% (mass fraction) Al addition to Mg. As the Al content of the alloy increases above 2%, the cutting forces tend to reduce along with the ductility owing to the grain boundary precipitation of intermetallic phase (β-Mg 17Al12). Cutting forces are able to increase as the cutting speed increases for all the alloys studied, and it's attributed to flank built up at the tip of the cutting tool during machining. © 2013 The Nonferrous Metals Society of China. Source

Acikgoz C.,Bilecik University
Renewable Energy

Utilization of renewable energy sources and the application of environmentally sound energy technologies are essential to sustainable development and will help to secure the quality of living and the well-being of the future generations. Turkey presently has considerable renewable energy sources. The most important renewable sources are hydropower, wind, solar, geothermal, and biomass. The use of renewable energy as a topic to study energy and its forms permits a novel way to motivate students, particularly those who energy topics taking conscience with the environment. This paper presents the analysis and classification of renewable energy sources and how to find out their origin and a way to motivate students in energy topics related to renewable sources and also, the development of didactic competencies in special blended learning arrangements for educationalists, trainers and lecturers in adult education in the field of renewable energies in Turkey. © 2010 Elsevier Ltd. Source

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