The use of zeotropic mixtures in well-designed heat pump cycles enables considerable performance improvements. Temperature glide matching the exchange processes and recovery expansion losses by internal decrease exergy destruction yield higher cycle performances. A case study for supply to district heating is presented, indicating increases COP from 4.3 a pure fluid standard 5.2 mixture with op...

Fossil fuels are still widely used for power generation. Nevertheless, it is possible to attain a shortand medium-term substantial reduction of greenhouse gas emissions to the atmosphere through a sequestration of the CO2 produced in fuels’ oxidation. The chemical-looping combustion (CLC) technique is based on a chemical intermediate agent, which gets oxidized in an air reactor and is then cond...

Most existing methods for energy transformation and use are inadvertently contaminating our water supplies, releasing greenhouse gasses into the atmosphere, emitting compounds that diminish the earth's protective blanket of ozone, and depleting the earth’s crust of natural resources. As a result, scientists and engineers are increasingly pursuing sustainable technologies so that costs associate...

This paper applies an exergy-based method on the two-dimensional airfoil and various threedimensional wing planforms to investigate the impact of exergy on aerodynamic designs. Our intent here is to report our efforts to couple a numerical code with an exergy analysis, a shape shifting algorithm and an optimization code to achieve desired airfoil and wing shapes. Exergy-based optimization is pe...

Exergy analysis is a powerful diagnostic tool in thermal systems performance evaluation. The use of such an analysis in seawater desalination processes is of growing importance to determine the sites of the highest irreversible losses. In the literature, exergy analyses of seawater desalination systems have sometimes modeled seawater as sodium chloride solutions of equivalent salt content or sa...

Exergy is a concept that is gaining an increasingly wider recognition as a proper measure for the actual energy resources consumed, when energy is used. Energy as such is indestructible, but exergy is not. As entropy is generated while energy is used, exergy is consumed. Exergy can be interpreted as the qualitative content of energy, or as energy in its highest quality. Therefore, there is an i...

In this work, we present the application of exergy analysis in the evaluation of the ethanol steam reforming (ESR) process in a catalytic membrane reactor (CMR) containing Pd-Ag membranes sandwiched by PdRh/CeO2 catalyst to produce fuel cell grade pure hydrogen (no sweep gas). ESR experiments were performed at T=873-923 K and P=4-12 bar. The fuel was a mixture of ethanol and distilled water wit...

The present paper describes the energy and exergy analysis of a reheat regenerative vapor power cycle. The plant consists of one boiler feed pump, one supercritical boiler, two steam turbines with a reheater in between, two feed water heaters (one open and one closed) and a condenser. The energy and exergy balance study has been carried-out for each component of the plant. Energy efficiency, ex...

Cogeneration may be defined as a system which contains electricity production and regain of the thermo value of exhaust gases simultaneously. The examination is based on the data’s of an active cogeneration plant. This study, it is aimed to determine which component of the system should be revised first to raise the efficiency and decrease the loss of exergy. For this purpose, second law analys...

Several fundamental concepts with respect to the second-law analysis (SLA) of the turbulent flows in gas turbines are discussed in this study. Entropy and exergy equations for compressible/incompressible flows in a rotating/non-rotating frame have been derived. The exergy transformation efficiency of a gas turbine as well as the exergy transformation number for a single process step have been p...