Energetic efficiency

Feedstock Fuel Energetic efficiency of fuel production process Fuel consumption (MJ/100 km) Primary energy use (GJprfin/ (year car))c... 

The energetic efficiency of the process refers to the energy input required to produce one unit of energy of fuel output. While this approach is rather simplistic, as it does not take into account upstream emissions, for instance from crude oil production or biomass supply, the general conclusions do not change. 

Finally, it must be mentioned that Graetz and Reilly [188] clearly pointed out that the conventional organometalhc synthesis of AIH3 is a costly procedure. This factor, together with its on-board irreversibility, calls for novel, very cost-effective, and energetically efficient techniques to regenerate AIH3 from spent Al powder. 

Greenbaum E (1998) Energetic efficiency of hydrogen photoevolution by algal water splitting. Biophys J 54 365-368... 

Measurement of Quantum Yield, Quantum Requirement, and Energetic Efficiency of the 02-Evolving System of Photosynthesis by a Simple Dye Reaction 127... 

Taking into consideration the main pressures channeling the evolution toward metabolic efficiency, that is, increasing free energy dissipation and energetic efficiency, one may single out... 

As to the mechanism explaining the evolutionary trend toward struc-turalization and therefore increased free energy dissipation and energetic efficiency, it still remains to be shown how the dynamic spatial order, so well described by Prigogine and so far the only principle that explains the biological order, became frozen in permanent biological structures. 

Gnaiger, E. (1983). Heat dissipation and energetic efficiency in animal anoxibiosis Economy contra power. J. Exp. Zoo, 228,471-490. 

Nowadays, the most common small-scale application of hydrogen is the use in residential or mobile fuel cell systems. Special requirements of this application are compact design, integrated CO-removal, high energetic efficiency, quick start-up and fast transient behavior. The proposed solutions comprise unit-operation-based concepts as well as multifunctional, micro-structured reactors. 

In the above discussion, the energy yields of the different anaerobic pathways of metabolism are expressed in terms of moles of ATP per mole of substrate fermented. This is the traditional way to express the energetic efficiency of fermentations and for some purposes it is informative and useful. However, it is important to recall that in vivo these pathways are linked to ATP utilizing pathways (usually ATPases). At steady state, rates of ATP synthesis by these fermentations equal rates of ATP utilization. For classical glycolysis, for example... 

The reaction rate, as measured by the current density, is also an important parameter as it determines the reactor size and thus capital cost of the process. To date, researchers have reported moderate to high current densities (200-600 mA-cm 2) using gas diffusion electrodes (GDEs) similar to those used in fuel cells. Further work is thus needed to significantly improve the energetic efficiency and current densities for CO2 reduction. 

Meinero, S. and Zerbinati, O. (2006) Oxidative and energetic efficiency of different electrochemical oxidation processes for chloroanilines abatement in aqueous medium. Chemosphere 64, 386-392. 

Objectives that have proved useful include optimal energetic efficiency or optimal cell growth rate [48, 204]. 

Chapter 6 describes solar-powered photocatalytic reactors for the conversion of organic water pollutants. Nonconcentrating reactors are identified as some of the most energetically efficient units. It is reported that the absorption of radiation is a critical parameter in the efficiency reactor evaluation. The radiative transfer equation (RTE) solution under the simplified conditions given by the PI approximation is proposed for these assessments. 

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