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Öğe A novel fish-drying technique for better environment, quality and sustainability(INDERSCIENCE ENTERPRISES LTD, 2010) Kilic, Aydin; Midilli, Adnan; Dincer, IbrahimThis study deals with the development of appropriate sustainable strategies for environmental-benign aquatic processing systems. In this regard, the interactions between the aquatic system and its environment are first defined. Second, the effect of environmental pollution decreasing the fish quality in the aquatic systems has been exposed. Third, some sustainable strategies for improving the fish quality and minimising the environmental impact of the aquatic system are developed. Finally, a case study is presented to study sustainability aspects and environmental impacts by considering some quality fish parameters. Accordingly, the results show that the Low-Temperature High-Velocity (LTHV) drying with smoking applied at 4 degrees C is an environmental-benign drying technique for better environmental sustainability.Öğe A parametric investigation of hydrogen energy potential based on H2S in Black Sea deep waters(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Midilli, Adnan; Ay, Murat; Kale, Ayfer; Veziroglu, T. NejatIn this study, a parametric investigation is carried out to estimate the hydrogen energy potential depending on the quantities of H2S in Black Sea deep waters. The required data for H2S in Black Sea deep waters are taken from the literature. For this investigation, the H2S concentration and water layer depth are taken into account, and 100% of conversion efficiency is assumed. Consequently, it is estimated that total hydrogen energy potential is approximately 270 million tons produced from 4.587 billion tons of H2S in Black Sea deep waters. Using this amount of hydrogen, it will be possible to produce 38.3 million TJ of thermal energy or 8.97 million GWh of electricity energy. Moreover, it is determined that total hydrogen potential in Black Sea deep waters is almost equal to 808 million tons of gasoline or 766 million tons of NG (natural gas) or 841 million tons of fuel oil or 851 million tons of natural petroleum. These values show that the hydrogen potential from hydrogen sulphur in Black Sea deep water will play an important role to supply energy demands of the regional countries. Thus, it can be said that hydrogen energy reserve in Black Sea is an important candidate for the future hydrogen energy systems. (c) 2006 International Association for Hydrogen Energy.Öğe Development of some exergetic parameters for PEM fuel cells for measuring environmental impact and sustainability(PERGAMON-ELSEVIER SCIENCE LTD, 2009) Midilli, Adnan; Dincer, IbrahimThis paper presents some new exergy-based parameters for PEM fuel cells to study how some of their operating aspects and system characteristics affect the environment and sustainability, based on some actual and literature data. The exergetic parameters of a PEM fuel cell developed here, in conjunction with environmental impact and sustainable development, are exergy efficiency, exergetic stability factor, environmental benign index and exergetic sustainability index. Any increase in efficiency improves exergetic sustainability. However, any increase in waste exergy ratio, exergy destruction factor, environmental destruction coefficient and environmental destruction index results in an increasing environmental impact of the PEM fuel cell and hence, a decreasing sustainability. Such parameters are expected to quantify how PEM fuel cells become more environmentally benign and sustainable. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.Öğe Effects of some micro-level exergetic parameters of a PEMFC on the environment and sustainability(INDERSCIENCE ENTERPRISES LTD, 2010) Midilli, Adnan; Dincer, IbrahimThis paper deals with studying the effects of some micro-level exergetic parameters of a Polymer Electrolyte Membrane Fuel Cell (PEMFC) on macro-level environmental pollution and sustainability. For this purpose, various exergetic, environmental and sustainability parameters of a PEMFC are investigated based on its operating and technical conditions. Consequently, these parameters may be utilised as some indicators in the development of energy and environmental policies for residential and industrial applications using PEMFC power systems. These parameters are also expected to help understand the linkage between micro-fuel-cell parameters and global aspects in terms of environmental impact and sustainable development and hence make PEMFCs more efficient, more environmentally benign and more sustainable.Öğe Exergetic performance analysis of a recirculating aquaculture system(PERGAMON-ELSEVIER SCIENCE LTD, 2010) Kucuk, Haydar; Midilli, Adnan; Ozdemir, Atilla; Cakmak, Eyuep; Dincer, IbrahimThis paper examines exergetic aspects of a Recirculation Aquaculture System (RAS) for Black Sea trout (Salmo, trutta labrax) fingerling rearing at the Trabzon Central Fisheries Research Institute, Turkey. In its thermodynamic analysis, each component of the RAS is treated as a steady-state steady flow system and its exergetic efficiencies are studied. In addition, the following parameters are measured and recorded in experiments: the mass flow rates, inlet and outlet temperatures and of the system components, surrounding temperatures, and electrical work utilized by the components in the RAS. Based on these experimental data, inlet and outlet exergy values, exergy losses, and exergetic efficiencies of each component in the system are determined to assess their performance. Moreover, the overall system exergy efficiency is determined. The results show that exergy efficiencies of the system components are highly affected by varying input exergy flows as a function of the surrounding temperature and chiller's operating period. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Green energy strategies for sustainable development(ELSEVIER SCI LTD, 2006) Midilli, Adnan; Dincer, Ibrahim; Ay, MuratIn this study we propose some green energy strategies for sustainable development. In this regard, seven green energy strategies are taken into consideration to determine the sectoral, technological, and application impact ratios. Based on these ratios, we derive a new parameter as the green energy impact ratio. In addition, the green energy-based sustainability ratio is obtained by depending upon the green energy impact ratio, and the green energy utilization ratio that is calculated using actual energy data taken from literature. In order to verify these parameters, three cases are considered. Consequently, it can be considered that the sectoral impact ratio is more important and should be kept constant as much as possible in a green energy policy implementation. Moreover, the green energy-based sustainability ratio increases with an increase of technological, sectoral, and application impact ratios. This means that all negative effects on the industrial, technological, sectoral and social developments partially and/or completely decrease throughout the transition and utilization to and of green energy and technologies when possible sustainable energy strategies are preferred and applied. Thus., the sustainable energy strategies can make an important contribution to the economies of the countries where green energy (e.g., wind, solar, tidal, biomass) is abundantly produced. Therefore, the investment in green energy supply and progress should be encouraged by governments and other authorities for a green energy replacement of fossil fuels for more environmentally benign and sustainable future. (c) 2005 Elsevier Ltd. All rights reserved.Öğe Hydrogen as a renewable and sustainable solution in reducing global fossil fuel consumption(PERGAMON-ELSEVIER SCIENCE LTD, 2008) Midilli, Adnan; Dincer, IbrahimIn this paper, hydrogen is considered as a renewable and sustainable solution for reducing global fossil fuel consumption and combating global warming and studied exergetically through a parametric performance analysis. The environmental impact results are then compared with the ones obtained for fossil fuels. In this regard, some exergetic expressions are derived depending primarily upon the exergetic utilization ratios of fossil fuels and hydrogen: the fossil fuel based global waste exergy factor, hydrogen based global exergetic efficiency, fossil fuel based global irreversibility coefficient and hydrogen based global exergetic indicator. These relations incorporate predicted exergetic utilization ratios for hydrogen energy from non-fossil fuel resources such as water, etc., and are used to investigate whether or not exergetic utilization of hydrogen can significantly reduce the fossil fuel based global irreversibility coefficient (ranging from 1 to +infinity) indicating the fossil fuel consumption and contribute to increase the hydrogen based global exergetic indicator (ranging from 0 to 1) indicating the hydrogen utilization at a certain ratio of fossil fuel utilization. In order to verify all these exergetic expressions, the actual fossil fuel consumption and production data are taken from the literature. Due to the unavailability of appropriate hydrogen data for analysis, it is assumed that the utilization ratios of hydrogen are ranged between 0 and 1. For the verification of these parameters, the variations of fossil fuel based global irreversibility coefficient and hydrogen based global exergetic indicator as the functions of fossil fuel based global waste exergy factor, hydrogen based global exergetic efficiency and exergetic utilization of hydrogen from non-fossil fuels are analyzed and discussed in detail. Consequently, if exergetic utilization ratio of hydrogen from non-fossil fuel sources at a certain exergetic utilization ratio of fossil fuels increases, the fossil fuel based global irreversibility coefficient will decrease and the hydrogen based global exergetic indicator will increase. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.Öğe Investigation of hydrogen production from boron compounds for PEM fuel cells(ELSEVIER SCIENCE BV, 2006) Ay, Murat; Midilli, Adnan; Dincer, IbrahimThis paper presents a comprehensive study of hydrogen production from sodium borohydride (NaBH4), which is synthesized from sodium tetraborate (Na2B4O7) decomposition, for proton exchange membrane (PEM) fuel cells. For this purpose, Na2B4O7 decomposition reaction at 450-500 degrees C under hydrogen atmosphere and NaBH4 decomposition reaction at 25-40 degrees C under atmospheric pressure are selected as a common temperature range in practice, and the inlet molar quantities of Na2B4O7 are chosen from 1 to 6 mol with 0.5 mol interval as well. In order to form NaBH4 solution with 7.5 wt.% NaBH4, 1 wt.% NaOH, 91.5 wt.% H2O, the molar quantities of NaBH4 are determined. For a PEM fuel cell operation, the required hydrogen production rates are estimated depending on 60, 65, 70 and 75 g of catalyst used in the NaBH4 solution at 25, 32.5 and 40 degrees C, respectively. It is concluded that the highest rate of hydrogen production per unit area from NaBH4 solution at 40 degrees C is found to be 3.834 x 10(-5) g H-2 s(-1) cm(-2) for 75 g catalyst. Utilizing 80% of this hydrogen production, the maximum amounts of power generation from a PEM fuel cell per unit area at 80 degrees C under 5 atm are estimated as 1.121 W cm(-2) for 0.016 cm by utilizing hydrogen from 75 g catalyst assisted NaBH4 solution at 40 degrees C. (c) 2005 Elsevier B.V. All rights reserved.Öğe Key strategies of hydrogen energy systems for sustainability(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Midilli, Adnan; Dincer, IbrahimHere we conduct a parametric study to investigate the effects of hydrogen energy utilization on the global stability and sustainability. In this regard, in order to derive the hydrogen energy based sustainability ratio, the green energy based sustainability ratio, as developed earlier, is modified to come up with a new parameter, namely "hydrogen energy utilization ratio through non-fossil fuels". We take actual historical data from key sources to determine the role of hydrogen energy for sustainability and make some future projections as the road map for hydrogen economy. In addition, an illustrative example on the hydrogen energy based sustainability ratio is presented by considering green energy sources such as solar, wind, hydro and nuclear to make hydrogen economy more environmentally benign and sustainable. It is found that hydrogen energy based global stability and sustainability ratios increase with the rise of hydrogen energy utilization ratio. The best results for hydrogen energy based sustainability ratio are obtained for the highest hydrogen energy impact ratios between 73.33% and 100%. In case of 10% of hydrogen energy utilization ratio, hydrogen based sustainability ratios for year 2010 are, respectively, determined to be 0.21%, 0.23%, 0.25%, 0.27% and 0.29% in 2.92% of hydrogen based global stability ratio by depending on the hydrogen energy impact ratios (=73.33%, 80%, 86.67%, 93.33% and 100%). In case of 20% of hydrogen energy utilization ratio, the hydrogen energy based sustainability ratios are found to be 1.09%, 1.19% 1.28%, 1.38% and 1.48% in 7.41%, respectively. The results are really encouraging in a way that hydrogen economy appears to be one of the most significant players for better sustainability. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
