The Experts below are selected from a list of 1959 Experts worldwide ranked by ideXlab platform
Arif Hepbasli - One of the best experts on this subject based on the ideXlab platform.
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exergoeconomic analysis of a central heating system from the generation stage to the building envelope
Energy and Buildings, 2012Co-Authors: Cem Tahsin Yucer, Arif HepbasliAbstract:This paper deals with exergoeconomic analysis of a dormitory heated by a conventional boiler in a central heating system. The energy and Exergy flows are examined from the generation stage to the envelope of the building. The energy and Exergy flows between the stages are obtained using a predesign tool for an optimized building design. Exergetic and exergoeconomic analyses of some heating equipment are comprehensively evaluated. A conventional boiler and a water heater in the central heating system are considered in the analysis. Based on the analysis results obtained, the total Exergy Input rate is calculated to be 1455 kW while the largest Exergy loss rate is found to be 987.6 kW. Exergetic efficiencies of the conventional boiler and the water heater are also obtained to be 15.6% and 20.4%, respectively.
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thermodynamic performance assessment of a novel air cooling cycle maisotsenko cycle
International Journal of Refrigeration-revue Internationale Du Froid, 2011Co-Authors: Hakan Caliskan, Arif Hepbasli, Ibrahim Dincer, Valeriy MaisotsenkoAbstract:Abstract This study presents energy and Exergy analyses and sustainability assessment of the novel evaporative air cooling system based on Maisotsenko cycle which allows the product fluid to be cooled in to a dew point temperature of the incoming air. In the energy analysis, Maisotsenko cycle’s wet-bulb and dew point effectiveness, COP and primary energy ratio rates are calculated. Exergy analysis of the system is then carried out for six reference temperatures ranging from 0 °C to 23.88 °C as the incoming air (surrounding) temperature. The specific flow Exergy, Exergy Input, Exergy output, Exergy destruction, Exergy loss, Exergy efficiency, exergetic COP, primary Exergy ratio and entropy generation rates are determined for various cases. Furthermore, sustainability assessment is obtained using sustainability index method. As a result, maximum Exergy efficiency is found to be 19.14% for a reference temperature of 23.88 °C where the optimum operation takes place.
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exergetic analysis and evaluation of a new application of gas engine heat pumps gehps for food drying processes
Applied Energy, 2011Co-Authors: Aysegul Gungor, Zafer Erbay, Arif HepbasliAbstract:In this study, three medicinal and aromatic plants (Foeniculum vulgare, Malva sylvestris L. and Thymus vulgaris) were dried in a pilot scale gas engine driven heat pump drier, which was designed, constructed and installed in Ege University, Izmir, Turkey. Drying experiments were performed at an air temperature of 45 °C with an air velocity of 1 m/s. In this work, the performance of the drier along with its main components is evaluated using Exergy analysis method. The most important component for improving the system efficiency is found to be the gas engine, followed by the exhaust air heat exchanger for the drying system. An Exergy loss and flow diagram (the so-called Grassmann diagram) of the whole drying system is also presented to give quantitative information regarding the proportion of the Exergy Input dissipated in the various system components, while the sustainability index values for the system components are calculated to indicate how sustainability is affected by changing the Exergy efficiency of a process. Gas engine, expansion valve and drying ducts account for more than 60% amount of Exergy in the system. The exergetic efficiency values are in the range of 77.68-79.21% for the heat pump unit, 39.26-43.24% for the gas engine driven heat pump unit, 81.29-81.56% for the drying chamber and 48.24-51.28% for the overall drying system.
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thermodynamic analysis of a building using Exergy analysis method
Energy and Buildings, 2011Co-Authors: Cem Tahsin Yucer, Arif HepbasliAbstract:Abstract This study deals with exergetic assessment of an educational building heated by a conventional boiler in a heating center. The heating system is examined from the generation stage to the envelope of the building. In general the heat loss calculations are made using both energy and Exergy analysis methods. The energy and Exergy flows between the stages are obtained using a pre-design tool for an optimized building design. Energy and Exergy losses are obtained to evaluate the performance of the system. A conventional boiler in the heating center and a fan coil unit in a room are considered in the analysis. Total Exergy Input rate is calculated to be 694.5 kW, while the largest Exergy loss rate is obtained to be 333 kW. Exergetic efficiencies of the conventional boiler and the fan coil unit are also found to be 13.4% and 37.6%, respectively.
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determination of optimum pipe diameter along with energetic and exergetic evaluation of geothermal district heating systems modeling and application
Energy and Buildings, 2008Co-Authors: Yildiz Kalinci, Arif Hepbasli, Ismail H TavmanAbstract:Abstract This study deals with determination of optimum pipe diameters based on economic analysis and the performance analysis of geothermal district heating systems along with pipelines using energy and Exergy analysis methods. In this regard, the Dikili geothermal district heating system (DGDHS) in Izmir, Turkey is taken as an application place, to which the methods presented here are applied with some assumptions. The system mainly consists of three cycles, namely (i) the transportation network, (ii) the Danistay region, and (iii) the Bariskent region. The thermal capacities of these regions are 21,025 and 7975 kW, respectively, while the supply (flow) and return temperature values of those are 80 and 50 °C, respectively. Based upon the assessment of the transportation network using the optimum diameter analysis method, minimum cost is calculated to be US$ 561856.906 year −1 for a nominal diameter of DN 300. The Exergy destructions in the overall DGDHS are quantified and illustrated using Exergy flow diagram. Furthermore, both energy and Exergy flow diagrams are exhibited for comparison purposes. It is observed through analysis that the Exergy destructions in the system particularly take place due to the Exergy of the thermal water (geothermal fluid) reinjected, the heat exchanger losses, and all pumps losses, accounting for 38.77%, 10.34%, 0.76% of the total Exergy Input to the DGDHS. Exergy losses are also found to be 201.12817 kW and 1.94% of the total Exergy Input to the DGDHS for the distribution network. For the system performance analysis and improvement, both energy and Exergy efficiencies of the overall DGDHS are investigated, while they are determined to be 40.21% and 50.12%, respectively.
Ibrahim Dincer - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic performance assessment of a novel air cooling cycle maisotsenko cycle
International Journal of Refrigeration-revue Internationale Du Froid, 2011Co-Authors: Hakan Caliskan, Arif Hepbasli, Ibrahim Dincer, Valeriy MaisotsenkoAbstract:Abstract This study presents energy and Exergy analyses and sustainability assessment of the novel evaporative air cooling system based on Maisotsenko cycle which allows the product fluid to be cooled in to a dew point temperature of the incoming air. In the energy analysis, Maisotsenko cycle’s wet-bulb and dew point effectiveness, COP and primary energy ratio rates are calculated. Exergy analysis of the system is then carried out for six reference temperatures ranging from 0 °C to 23.88 °C as the incoming air (surrounding) temperature. The specific flow Exergy, Exergy Input, Exergy output, Exergy destruction, Exergy loss, Exergy efficiency, exergetic COP, primary Exergy ratio and entropy generation rates are determined for various cases. Furthermore, sustainability assessment is obtained using sustainability index method. As a result, maximum Exergy efficiency is found to be 19.14% for a reference temperature of 23.88 °C where the optimum operation takes place.
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exergoeconomic analysis of the gonen geothermal district heating system for buildings
Energy and Buildings, 2009Co-Authors: Zuhal Oktay, Ibrahim DincerAbstract:Abstract This paper presents an application of an exergoeconomic model, through Exergy and cost accounting analyses, to the Gonen geothermal district heating system (GDHS) in Balikesir, Turkey for the entire system and its components. This exergoeconomic model is used to reveal the cost formation process and the productive interaction between components. The Exergy destructions in the overall Gonen GDHS are quantified and illustrated for a reference temperature of 4 °C. The results indicate that the Exergy destructions in the system occur primarily as a result of losses in the cooled geothermal water injected back into the reservoir, pumps, heat exchangers, and pipelines. Total Exergy destruction and reinjection Exergy of the cooled geothermal water result in 1010 kW (accounting for 32.49%), 320.3 kW (accounting for 10%) of the total Exergy Input to the Gonen GDHS, respectively. Both energy and Exergy efficiencies of the overall Gonen GDHS are also investigated to analyze the system performance, as these efficiencies are determined to be 42% and 50%, respectively. It is found that an increase of the load condition leads to a decrease in the overall thermal costs, which will result in more cost-effective energy systems for buildings.
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energy and Exergy analysis of the gonen geothermal district heating system turkey
Geothermics, 2005Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:This paper describes a performance evaluation of the Gonen geothermal district heating system (GGDHS) in Balikesir, Turkey, based on energy and Exergy analyses. The Exergy destructions in the overall GGDHS are quantified and illustrated using energy and Exergy flow diagrams for a reference temperature of 6 °C. The results indicate that the Exergy destructions in the system occur primarily as a result of losses in the pumps, heat exchangers, and pipelines, as well as losses associated with cooled geothermal waters injected back into the reservoir. These losses amount to 14.81%, 7.11%, 1.06%, and 12.96% of the total Exergy Input to the GGDHS, respectively. Both energy and Exergy efficiencies of the overall GGDHS were investigated to analyze and improve system performance. The efficiencies were determined to be 45.91% and 64.06%, respectively.
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energy and Exergy analysis of salihli geothermal district heating system in manisa turkey
International Journal of Energy Research, 2005Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:This study deals with an energy and Exergy analysis of Salihli geothermal district heating system (SGDHS) in Manisa, Turkey. In the analysis, actual system data are used to assess the district heating system performance, energy and Exergy efficiencies, specific Exergy index, exergetic improvement potential and Exergy losses. Energy and Exergy losses throughout the SGDHS are quantified and illustrated in the flow diagram. The Exergy losses in the system, particularly due to the fluid flow, take place in the pumps and the heat exchanger, as well as the Exergy losses of the thermal water (e.g. geothermal fluid) and the natural direct discharge of the system. As a result, the total Exergy losses account for 2.22, 17.88 and 20.44%, respectively, of the total Exergy Input to the entire SGDHS. The overall energy and Exergy efficiencies of the SGDHS components are also studied to evaluate their individual performances and determined to be 55.5 and 59.4%, respectively. Copyright © 2005 John Wiley & Sons, Ltd.
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Energy and Exergy analysis of geothermal district heating systems: an application
Building and Environment, 2005Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:In this study we present an energy and Exergy assessment and modeling of geothermal district heating systems for their system analysis, performance evaluation and optimization. A comprehensive case study is conducted in Balcova geothermal district heating system (BGDHS) in Izmir, Turkey and actual thermal data are collected and employed for analysis. Using actual system data, an assessment of the district heating system performance, energy and Exergy efficiencies, and Exergy destructions in the system is conducted in this regard. The Exergy destructions in the overall BGDHS are quantified and illustrated using Exergy flow diagram. Furthermore, both energy and Exergy flow diagrams are exhibited for comparison purposes. It is observed through analysis that the Exergy destructions in the system particularly take place as the Exergy of the fluid lost in the pumps, the heat exchanger losses, the Exergy of the thermal water (geothermal fluid) reinjected and the natural direct discharge (hot water distribution losses) of the system, accounting for 1.64%, 8.57%, 14.84% and 28.96%, respectively, of the total Exergy Input to the BGDHS. For system performance analysis and improvement, both energy and Exergy efficiencies of the overall BGDHS are investigated and are determined to be 41.9% and 46%, respectively.
Leyla Ozgener - One of the best experts on this subject based on the ideXlab platform.
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energy and Exergy analysis of the gonen geothermal district heating system turkey
Geothermics, 2005Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:This paper describes a performance evaluation of the Gonen geothermal district heating system (GGDHS) in Balikesir, Turkey, based on energy and Exergy analyses. The Exergy destructions in the overall GGDHS are quantified and illustrated using energy and Exergy flow diagrams for a reference temperature of 6 °C. The results indicate that the Exergy destructions in the system occur primarily as a result of losses in the pumps, heat exchangers, and pipelines, as well as losses associated with cooled geothermal waters injected back into the reservoir. These losses amount to 14.81%, 7.11%, 1.06%, and 12.96% of the total Exergy Input to the GGDHS, respectively. Both energy and Exergy efficiencies of the overall GGDHS were investigated to analyze and improve system performance. The efficiencies were determined to be 45.91% and 64.06%, respectively.
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energy and Exergy analysis of salihli geothermal district heating system in manisa turkey
International Journal of Energy Research, 2005Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:This study deals with an energy and Exergy analysis of Salihli geothermal district heating system (SGDHS) in Manisa, Turkey. In the analysis, actual system data are used to assess the district heating system performance, energy and Exergy efficiencies, specific Exergy index, exergetic improvement potential and Exergy losses. Energy and Exergy losses throughout the SGDHS are quantified and illustrated in the flow diagram. The Exergy losses in the system, particularly due to the fluid flow, take place in the pumps and the heat exchanger, as well as the Exergy losses of the thermal water (e.g. geothermal fluid) and the natural direct discharge of the system. As a result, the total Exergy losses account for 2.22, 17.88 and 20.44%, respectively, of the total Exergy Input to the entire SGDHS. The overall energy and Exergy efficiencies of the SGDHS components are also studied to evaluate their individual performances and determined to be 55.5 and 59.4%, respectively. Copyright © 2005 John Wiley & Sons, Ltd.
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Energy and Exergy analysis of geothermal district heating systems: an application
Building and Environment, 2005Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:In this study we present an energy and Exergy assessment and modeling of geothermal district heating systems for their system analysis, performance evaluation and optimization. A comprehensive case study is conducted in Balcova geothermal district heating system (BGDHS) in Izmir, Turkey and actual thermal data are collected and employed for analysis. Using actual system data, an assessment of the district heating system performance, energy and Exergy efficiencies, and Exergy destructions in the system is conducted in this regard. The Exergy destructions in the overall BGDHS are quantified and illustrated using Exergy flow diagram. Furthermore, both energy and Exergy flow diagrams are exhibited for comparison purposes. It is observed through analysis that the Exergy destructions in the system particularly take place as the Exergy of the fluid lost in the pumps, the heat exchanger losses, the Exergy of the thermal water (geothermal fluid) reinjected and the natural direct discharge (hot water distribution losses) of the system, accounting for 1.64%, 8.57%, 14.84% and 28.96%, respectively, of the total Exergy Input to the BGDHS. For system performance analysis and improvement, both energy and Exergy efficiencies of the overall BGDHS are investigated and are determined to be 41.9% and 46%, respectively.
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energy and Exergy assessment of salihli geothermal district heating system
2005Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:The present study undertakes an energy and Exergy analysis of the Salihli geothermal district heating system (SGDHS) in Manisa, Turkey. In the analysis, actual system data obtained on 1 February 2004 directly from the system are used to assess the district heating system performance, through energy and Exergy efficiencies. Energy and Exergy losses within SGDHS are determined and compared (for a dead state temperature of 0°C). It is found that the Exergy losses in the system are essentially due to the fluid flow and take place in the pumps and heat exchangers, as well as the Exergy losses of the thermal water (e.g., geothermal fluid) and the natural direct discharge of the system. As a result, the total Exergy losses account for 1.72% in pumps, 16.47% in the discharge and 23.62% in heat exchangers, based on the total Exergy Input to the entire SGDHS. The overall energy and Exergy efficiencies of the system are found to be 53.73% and 58.20%, respectively. In addition, the efficiencies of the system elements are studied to evaluate the individual performances and performance improvement possibilities.
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thermo mechanical Exergy analysis of balcova geothermal district heating system in izmir turkey
Journal of Energy Resources Technology-transactions of The Asme, 2004Co-Authors: Leyla Ozgener, Arif Hepbasli, Ibrahim DincerAbstract:This paper deals with a thermo-mechanical Exergy analysis of Balcova Geothermal District Heating System (BGDHS) in Izmir, Turkey using actual system data and an assessment of the district heating system performance, energy and Exergy efficiencies, and Exergy destructions. The Exergy destructions in the overall BGDHS are quantified and illustrated using an Exergy flow diagram. Also, both energy and Exergy flow diagrams are compared. The Exergy destructions in the system particularly occurs in terms of the Exergy of the fluid lost in the pumps, the heat exchanger losses, the Exergy of the thermal water (geothermal fluid) reinjected and the natural direct discharge of the system, accounting for 3.06%, 7.24%, 22.66% and 24.1%, respectively of the total Exergy Input to the BGDHS. Both energy and Exergy efficiencies of the overall BGDHS are investigated for system performance analysis and improvement and are determined to be 37.60% and 42.94%, respectively.
Ismail H Tavman - One of the best experts on this subject based on the ideXlab platform.
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determination of optimum pipe diameter along with energetic and exergetic evaluation of geothermal district heating systems modeling and application
Energy and Buildings, 2008Co-Authors: Yildiz Kalinci, Arif Hepbasli, Ismail H TavmanAbstract:Abstract This study deals with determination of optimum pipe diameters based on economic analysis and the performance analysis of geothermal district heating systems along with pipelines using energy and Exergy analysis methods. In this regard, the Dikili geothermal district heating system (DGDHS) in Izmir, Turkey is taken as an application place, to which the methods presented here are applied with some assumptions. The system mainly consists of three cycles, namely (i) the transportation network, (ii) the Danistay region, and (iii) the Bariskent region. The thermal capacities of these regions are 21,025 and 7975 kW, respectively, while the supply (flow) and return temperature values of those are 80 and 50 °C, respectively. Based upon the assessment of the transportation network using the optimum diameter analysis method, minimum cost is calculated to be US$ 561856.906 year −1 for a nominal diameter of DN 300. The Exergy destructions in the overall DGDHS are quantified and illustrated using Exergy flow diagram. Furthermore, both energy and Exergy flow diagrams are exhibited for comparison purposes. It is observed through analysis that the Exergy destructions in the system particularly take place due to the Exergy of the thermal water (geothermal fluid) reinjected, the heat exchanger losses, and all pumps losses, accounting for 38.77%, 10.34%, 0.76% of the total Exergy Input to the DGDHS. Exergy losses are also found to be 201.12817 kW and 1.94% of the total Exergy Input to the DGDHS for the distribution network. For the system performance analysis and improvement, both energy and Exergy efficiencies of the overall DGDHS are investigated, while they are determined to be 40.21% and 50.12%, respectively.
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determination of optimum pipe diameter along with energetic and exergetic evaluation of geothermal district heating systems modeling and application
Energy and Buildings, 2008Co-Authors: Yildiz Kalinci, Arif Hepbasli, Ismail H TavmanAbstract:Abstract This study deals with determination of optimum pipe diameters based on economic analysis and the performance analysis of geothermal district heating systems along with pipelines using energy and Exergy analysis methods. In this regard, the Dikili geothermal district heating system (DGDHS) in Izmir, Turkey is taken as an application place, to which the methods presented here are applied with some assumptions. The system mainly consists of three cycles, namely (i) the transportation network, (ii) the Danistay region, and (iii) the Bariskent region. The thermal capacities of these regions are 21,025 and 7975 kW, respectively, while the supply (flow) and return temperature values of those are 80 and 50 °C, respectively. Based upon the assessment of the transportation network using the optimum diameter analysis method, minimum cost is calculated to be US$ 561856.906 year −1 for a nominal diameter of DN 300. The Exergy destructions in the overall DGDHS are quantified and illustrated using Exergy flow diagram. Furthermore, both energy and Exergy flow diagrams are exhibited for comparison purposes. It is observed through analysis that the Exergy destructions in the system particularly take place due to the Exergy of the thermal water (geothermal fluid) reinjected, the heat exchanger losses, and all pumps losses, accounting for 38.77%, 10.34%, 0.76% of the total Exergy Input to the DGDHS. Exergy losses are also found to be 201.12817 kW and 1.94% of the total Exergy Input to the DGDHS for the distribution network. For the system performance analysis and improvement, both energy and Exergy efficiencies of the overall DGDHS are investigated, while they are determined to be 40.21% and 50.12%, respectively.
Mehmet Kanoglu - One of the best experts on this subject based on the ideXlab platform.
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thermoeconomic assessment of a sustainable municipal wastewater treatment system
Renewable Energy, 2012Co-Authors: Aysegul Abusoglu, Sinan Demir, Mehmet KanogluAbstract:This paper presents the thermoeconomic analysis and assessment of a municipal wastewater treatment system. Operation of an existing municipal wastewater treatment plant is described in detail and a thermoeconomical methodology based on exergoeconomic relations and the specific Exergy costing (SPECO) method is provided to allocate cost flows through subcomponents of the plant. SPECO method is based on a step by step procedure which begins from identification of energy and Exergy values of all states defined in the present system through fuel (F) and product (P) approach and ends at the point of establishing related Exergy based cost balance equations together with auxiliary equations. The system treats nearly 222,000 m3 domestic wastewater per day by using the primary and secondary treatment systems. Activated sludge is digested in the anaerobic digestion reactors to produce biogas with a 60% methane content. For each 1 m3 biogas produced in the wastewater treatment plant, 68.26 kg of sludge with the dry matter content of 5.0% is digested. The de-watered digested sludge with the dry matter content of 22% is considered as a waste and used for agricultural land applications, currently. The actual exergetic efficiency of the wastewater treatment plant is determined to be 34% which indicates that 66% of the total Exergy Input to the plant, mainly by sewage and power consumptions, is destroyed. The exergetic cost rate and the specific unit exergetic cost of the treated wastewater at the exit of the WWTP are found to be 62.05 $/h and 3.804 ¢/m3, respectively. The corresponding costs are 81.90 $/h and 1.907 ¢/m3 for digested sludge at the exit of secondary anaerobic digestion reactor and de-watering unit; and 175.9 $/h and 13.48 ¢/m3 for the biogas produced at the exit of primary and secondary anaerobic digestion reactors, respectively.
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performance and parametric investigation of a binary geothermal power plant by Exergy
Renewable Energy, 2008Co-Authors: Mehmet Kanoglu, Ali BolatturkAbstract:Exergy analysis of a binary geothermal power plant is performed using actual plant data to assess the plant performance and pinpoint sites of primary Exergy destruction. Exergy destruction throughout the plant is quantified and illustrated using an Exergy diagram, and compared to the energy diagram. The sites with greater Exergy destructions include brine reinjection, heat exchanger and condenser losses. Exergetic efficiencies of major plant components are determined in an attempt to assess their individual performances. The energy and Exergy efficiencies of the plant are 4.5% and 21.7%, respectively, based on the energy and Exergy of geothermal water at the heat exchanger inlet. The energy and Exergy efficiencies are 10.2% and 33.5%, respectively, based on the heat Input and Exergy Input to the binary Rankine cycle. The effects of turbine inlet pressure and temperature and the condenser pressure on the Exergy and energy efficiencies, the net power output and the brine reinjection temperature are investigated and the trends are explained.
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Exergy analysis of a dual level binary geothermal power plant
Geothermics, 2002Co-Authors: Mehmet KanogluAbstract:Exergy analysis of a 12.4 MW existing binary geothermal power plant is performed using actual plant data to assess the plant performance and pinpoint sites of primary Exergy destruction. Exergy destruction throughout the plant is quantified and illustrated using an Exergy flow diagram, and compared to the energy flow diagram. The causes of Exergy destruction in the plant include the Exergy of the working fluid lost in the condenser, the Exergy of the brine reinjected, the turbine-pump losses, and the preheater–vaporizer losses. The Exergy destruction at these sites accounts for 22.6, 14.8, 13.9, and 13.0% of the total Exergy Input to the plant, respectively. Exergetic efficiencies of major plant components are determined in an attempt to assess their individual performances. The exergetic efficiency of the plant is determined to be 29.1% based on the Exergy of the geothermal fluid at the vaporizer inlet, and 34.2% based on the Exergy drop of the brine across the vaporizer–preheater system (i.e. Exergy Input to the Rankine cycle). For comparison, the corresponding thermal efficiencies for the plant are calculated to be 5.8 and 8.9%, respectively.