Life cycle analysis exergy

Ayres, R.U. Ayres, L.W. Martinas, K. Exergy, waste accounting, and life-cycle analysis. Energy 1998,23,355-363. 

Chapters 9 through 12 demonstrate thermodynamic, or exergy analysis of industrial processes. First, Chapter 9 deals with the most common energy conversion processes. Then, Chapter 10 presents this analysis for an important industrial separation process, that of propane and propylene. Finally, Chapter 11 analyzes two industrial chemical processes the production of polyethylene. Chapter 12 is included to discuss life cycle analysis in particular its extension into exergetic life cycle analysis, which includes the "fate" or history of the quality of energy. 

In the previous chapters, thermodynamic analysis is used to improve processes. However, as pointed out in Chapter 9 (Energy Conversion), the exergy analysis did not make any distinction between the combustion of coal and natural gas and, as a result, could not make any statements regarding toxicity or environmental impact of exploration, production and use of the two fuels. A technique that can do this is LCA. What exactly is life cycle analysis In ISO 14040 [1], life cycle analysis (or life cycle assessment) is defined as "the compilation and evaluation of the inputs, outputs and potential environmental impacts of a product throughout its life cycle."... 

One year before Ayres publications [7,8], Cornelissen [9] completed his PhD dissertation in which he had combined life cycle analysis with exergy analysis. He called this extension of LCA exergetic life cycle analysis. He explained that ELCA should be part of every LCA because the loss via dissipation of exergy is one of the most important parameters to properly assess a process and measure the depletion of natural resources. Cornelissen even went one step further and extended ELCA to what he called zero-emission ELCA. In this extension of ELCA, the exergy required for the abatement of emissions, that is, the removal and reuse of environmentally friendly storage of emissions, is accounted for. Cornelissen illustrated his ideas with examples of... 

Generally, the criteria used in comparing the three electricity-generating systems are complex and difficult to evaluate and sometimes contradictory (e.g. safety sometimes means more expensive). More complex sustainability criteria such as extended exergy accounting or life cycle analysis [13] should be applied for more exact comparisons for all considered systems. 

Next, Cornelissen extended the LCA study to include the effect of depletion of natural resources making use of ELCA, the exergetic life cycle assessment. In this analysis a full mass and energy balance was made, that is, a first law analysis. Exergy values for all mass and energy streams were included in accordance with the Tables 6.1, 6.2, 6.3, 7.1, 7.2, 7.3 and 7.4 in Chapters 6 and 7. This analysis clearly showed where work was available in inputs and outputs and where it was lost. He could show that the cup scored less favorable than the mug in terms of depletion of natural resources (817 MJ vs. 442 MJ). 

Bakshi, B.R. and Hau, J. L., Using exergy analysis for improving life cycle inventory databases, AlChE Sustainability Engineering Conference Proceedings, Austin, TX, November pp. 131-134, 2004. 

Exergy analysis can be used to compare FP-FC systems with rechargeable batteries and combustion engines. Other important aspects, in addition to exergetic efficiency, are environmental impact, safety and life cycle cost. Efficient fuel utilization is particularly important for larger FP-FC systems. For small systems, the energy... 

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