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    Energy and exergy analyses of combined thermochemical and sensible thermal energy storage systems for building heating applications
    (2012) Caliskan H.; Dincer I.; Hepbasli A.
    In this study, energy and exergy analyses are conducted to model novel integrated systems, combining thermochemical and sensible thermal energy storage (TES) systems, for building heating applications, and their performance is assessed for three various dead state temperatures of 8 °C, 9 °C and 10 °C. The present overall system consists of a floor heating system (FHS), System-A and System-B. The FHS is accommodated in the building floor and supported with a floor heating unit (FHU), a pump and an energy receiver unit (ERU). The System-A includes a thermochemical TES (TTES), a solar collector, a heat exchanger, a pump and a hot well of aquifer TES (ATES). Also, the components of System-B are a cold well of ATES and a HP unit. The system is designed to have the aquifer and thermochemical TES systems supplying the necessary heating for buildings. The FHS in the building can be operated with System-A (the TTES and hot well of ATES) and the System-B (the cold well of ATES and HP) to provide the same heating load in a more efficient manner. The maximum exergy efficiency is calculated for the hot well of ATES to be 88.78% at 8 °C dead state temperature, while the minimum one is obtained for the charging process of TTES as 21.69% among the TES systems considered. If all the system components are considered, the FHU has the highest exergy efficiency as 98.08% at a dead state temperature of 8 °C. Among the TES systems, the exergy efficiencies for the aquifer TES (ranging between 56.38% and 88.78%) are generally higher than the corresponding thermochemical TES efficiencies (ranging from 46.71% to 84.80%). Thus, the results show that the aquifer TES system is exergetically more efficient than the thermochemical TES system. © 2011 Elsevier B.V. All rights reserved.
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    Exergetic analysis and assessment of industrial furnaces
    (2010) Caliskan H.; Hepbasli A.
    This study presents exergy analysis of a natural gas-fired radiant tube-heating furnace. In the analysis, actual data over a test period of 3 h were used. Exergy efficiencies, destructions, losses, and entropy generation of the furnace were determined. For an average furnace temperature of 666.6°C, average exergy efficiency value was calculated to be 9.6%. The exergy destruction rate was obtained to be 5.34 kW while exergy rates of the flue gases, exergy losses, and exergy steel were 12.53 kW, 44.28 kW, and 6.6 kW, respectively. On the other hand, the exergy rate of the product (steel) was found to be between 4.61 kW and 9.88 kW over the 15 min test periods, and it reached a maximum rate at the end of the second hour. Copyright © 2010 by ASME.
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    Exergy analysis of engines fuelled with biodiesel from high oleic soybeans based on experimental values
    (2010) Caliskan H.; Tat M.E.; Hepbasli A.; Van Gerpen J.H.
    This study dealt with energy and exergy analyses of a John Deere 4045T diesel engine run with no. 2 diesel fuel, Soybean oil Methyl Ester (SME) and High-Oleic soybean oil Methyl Ester (HOME) at 1400 1/min. It was aimed at determining energy and exergy efficiencies, energy losses and exergy destructions of the combustion process and comparing exergetically the fuels used. The specific exergy of the fuels was calculated to be ?fuel,No.2 Diesel > ?fuel,HOME > ?fuel,SME, while energy (thermal) and exergy efficiencies were 40.5% and 37.8%, respectively. There were no statistically significant differences between the fuels based on the Tukey method. Copyright © 2010 Inderscience Enterprises Ltd.
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    A review on exergetic analysis and assessment of various types of engines
    (2010) Caliskan H.; Tat M.E.; Hepbasli A.
    This study presents a review on energy and exergy analysis of Otto and Diesel engines. Calculation methods of the analysis are discussed in detail. Previous studies, from 1963 to 2008, are chronologically listed and studied. The test engines had different cylinder numbers, speeds and rated powers. Engine specifications and test bench schematics are given in tables and figures. The best exergetic efficiency is achieved with four-stroke, four-cylinder, turbocharged Diesel engines at about 30% excepting to stationary Diesel engine. It is considered that exergetic efficiency can be higher at lower speeds between 1140 1/min and 2200 1/min. Copyright © 2010 Inderscience Enterprises Ltd.