Eco-efficiency measurement and material balance principle:an application in power plants Malmquist Luenberger Index

Incorporating Material Balance Principle (MBP) in industrial and agricultural performance measurement systems with pollutant factors has been on the rise in recent years. Many conventional methods of performance measurement have proven incompatible with the material flow conditions. This study will address the issue of eco-efficiency measurement adjusted for pollution, taking into account materials flow conditions and the MBP requirements, in order to provide ‘real’ measures of performance that can serve as guides when making policies. We develop a new approach by integrating slacks-based measure to enhance the Malmquist Luenberger Index by a material balance condition that reflects the conservation of matter. This model is compared with a similar model, which incorporates MBP using the trade-off approach to measure productivity and eco-efficiency trends of power plants. Results reveal similar findings for both models substantiating robustness and applicability of the proposed model in this paper

Energetic and exergetic assessment of the industrial sector at varying dead (reference) state temperatures: A review with an illustrative example

One of the keystones for obtaining sustainable development is the use of exergy analysis. The present study deals with the assessment of energy and exergy utilization efficiencies in the industrial sector. Attempts have also been made at understanding the effect of varying dead (reference) state temperatures on these efficiencies. In this context, the methodology used is presented first. It is then applied to Turkey, which is selected as an application country, based on the actual data for 2003. Finally, the results obtained are evaluated and discussed. The Turkish industrial sector (TIS) considered includes iron-steel, chemical-petrochemical, petrochemical-feedstock, cement, fertilizer, sugar, non-iron metal industry and others such as textile and yarn, glass and glassware production, paper, beverage and cigarette, food, wood, leather, etc. All activities in this sector are produced by using electricity and heat energy. Parametric expressions of energy and exergy efficiencies are developed as a function of the dead-state temperature. The energy and exergy efficiency values for the TIS are found to vary from 51.95% to 80.82% and 25.30% to 29.50% at the dead-state temperature variations between 0 and 25 °C, respectively. It is expected that this study will be very beneficial in developing energy policies of countries from the exergy management point of view. © 2007 Elsevier Ltd. All rights reserved.The authors are grateful for the present work by the Ministry of Energy and Natural Resources of Turkey and World Energy Council Turkish National Committee. -

Thermoeconomic analysis of energy utilization in the residential-commercial sector: An application

Thermoeconomic analysis is a very useful tool for investigators in engineering and other disciplines since its methodology includes the quantities such as mass, energy, exergy and cost. This study deals with this analysis of energy utilization in the residential-commercial sector (RCS). In this regard, the relations between capital costs and thermodynamic losses for subsectors in the RCS are investigated. In the analysis, Turkey is taken as an application country based on its actual and projected values for the years 1991, 1993, 1995, 1999, 2000 and 2001, and for the year 2020, respectively. It is observed from the results obtained that the maximum exergy destructions in the system particularly occur due to the utilization of the large-cost and high-quality energy sources like petroleum, natural gas carriers in the low-energy needs. In conjunction with this, the values for the total exergy losses are found to vary from 486.43 to 2797.28 PJ, while those for the improvement potential are obtained to range from 58.80 to 1870 PJ in the Turkish RCS for the analyzed years. The ratio of thermodynamic loss rate-to-capital cost values is also calculated to be in the range of 0.76-1.01. It is expected that the results presented here would be beneficial to the researchers, government administration and engineers working in the area of modeling the subsectors of countries using thermoeconomic analysis method. © 2007 Elsevier Ltd. All rights reserved

A review and assessment of the energy utilization efficiency in the Turkish industrial sector using energy and exergy analysis method

Exergy has been seen a key component for a sustainable society, and in the recent years exergy analysis has been widely used in the design, simulation and performance evaluation of thermal and thermo chemical systems. A particular thermo dynamical system is the society of a country, while the energy utilization of a country can be assessed using exergy analysis to gain insights into its efficiency and potential for improvements. Energy and exergy utilization efficiencies in the Turkish industrial sector (TIS) over the period from 1990 to 2003 are reviewed and evaluated in this study. Energy and exergy analyses are performed for eight industrial modes, namely iron-steel, chemical-petrochemical, petrochemical-feedstock, cement, fertilizer, sugar, non-metal industry, other industry, while in the analysis the actual data are used. Sectoral energy and exergy analyses are conducted to study the variations of energy and exergy efficiencies for each subsector throughout the years studied, and these heating and overall energy and exergy efficiencies are compared for the eight subsectors. The chemical and petrochemical subsector, and the iron and steel subsector appear to be the most energy and exergy efficient sectors, respectively. The energy utilization efficiencies for the Turkish overall industrial sector range from 63.45% to 70.11%, while the exergy utilization efficiencies vary from 29.72% to 33.23% in the analyzed years. Exergetic improvement potential for this sector is also determined to be 681 PJ in 2003, with an average increase rate of 9.5% annually for the analyzed years. It may be concluded that the methodology used in this study is practical and useful for analyzing sectoral and subsectoral energy and exergy utilization to determine how efficient energy and exergy are used in the sector studied. It is also expected that this study will be helpful in developing highly applicable and productive planning for energy policies. © 2006 Elsevier Ltd. All rights reserved.The authors are grateful for the support provided for the present work by the Ministry of Energy and Natural Resources of Turkey and World Energy Council Turkish National Committee. -