On the basis of the exergy analysis, a performance optimization is carried out for a generalized irreversible refrigerator model, which takes into account the heat resistance, heat leakage and internal irreversibility losses. A new ecological criterion, named coefficient of performance of exergy (COPE), defined as the dimensionless ratio of the exergy output rate to the exergy loss rate, is pro...

This study presents comparative energy and exergy analyses of a single cylinder, four stroke Ruston diesel engine. The test was conducted by varying the load between zero and maximum while keeping the engine speed constant. Then, using the steady-state data along with energy and exergy balance equations, various performance parameters of the engine were measured. From the study it was found tha...

The current method used for calculating societal aggregated exergy efficiencies is reviewed. Cooling is introduced as an end-use category; conversion efficiencies for heating processes are obtained for each energy carrier; and electricity shares per end-use are retrieved for each sector, improving the accuracy of the estimated values of aggregated exergy efficiencies. We show that: (1) cooling ...

exergy analysis and response surface methodology (rsm) is applied to reduce the exergy loss and improve energy and exergy efficiency of acetic acid production plant. exergy analysis is run as a thermodynamic tool to assess exergy loss in reactor and towers of acetic acid production process. the process is simulated in aspen plus(v.8.4) simulator and the necessary thermodynamics data for calcula...

The performance and design criteria of air powered multistage turbines are studied thermodynamically in this paper. In-house code is developed in the C++ environment and the characteristics of four-stage turbines with inter-heating are analyzed in terms of maximum thermal efficiency, maximum exergy efficiency and maximum work output over the inlet temperature range of 293 K–793 K with inlet pre...

The phrase ‘emergy baseline’ refers to the total yearly environmental support to the geobiosphere in terms of the emergy concept, and should include all three fundamental sources of exergy (i.e. sunlight, tidal exergy and deep earth heat). Ever since its introduction, the emergy baseline has undergone a continuous revision process, which, however, has so far focussed on the underlying equations...

The use of exergy to correlate energy-utilization efficiencies and energy research investments is described. Specifically, energy and exergy losses are compared with energy research and development expenditures, demonstrating that the latter correlates with energy losses, even though it would be more sensible to allocate energy research and development funding in line with exergy losses, as the...

Tubular solar thermal receivers suitable for central towers are modelled using energy and exergy analysis, in a way that allows individual inspection of the the irreversibilities associated with the various receiver heat transfer processes occurring. The model was used to compare the behaviour of four working fluids: molten salt (NaNO3/KNO3), liquid sodium metal, supercritical carbon dioxide, a...

In this study, an analysis of energy and exergy utilization in the utility sector of Jordan by considering the sectoral energy and exergy flows for the years 2007-2011 has been conducted based on real data obtained from main generators in Jordan. The overall energy and exergy efficiencies, for the entire utility sector, are found to be in the range of 35.1 to 38.1%. It is expected that the resu...

and Tribus, 1962), which is also named exergoeconomics (Bejan et al, 1996) and exergonomics (Yantovskii, 1994). The concept of utility is a central concept in macroeconomics. Utility is also closely related to exergy, and an exergy tax is an example of how exergy could be introduced into macroeconomics. This paper introduces and clarifies important concepts in the development of a sustainable e...