Thermodynamic efficiency, measure

Much of the potential for improvement in technical energy efficiencies in industrial processes depends on how closely such processes have approached their thermodynamic limit. There are two types of energy efficiency measures (1) more efficient use in existing equipment through improved operation, maintenance or retrofit of equipment and (2) use of more efficient new equipment by introducing more efficient processes and systems at the point of capital turnover or expansion of production. More efficient practices and new technologies exist for all industrial sectors. Table 2 outlines some examples of energy efficiency improvement techniques and practices. 

De Nevers, N., and Seader, J. D. 1980. Lost work A measure of thermodynamic efficiency. Energy 5 757-69. 

De-Nevers, Joel and Seader, J. D. "Lost Work A Measure of Thermodynamic Efficiency", Energy. Vol. 5, No. 8-9, August-Sept. 1980, pp 7859-769... 

A measure of how efficiently a system can yield energy with minimum heat loss, we define the thermodynamic efficiency as the ratio of useful work output (over a complete cycle) divided by heat input ... 

One measure of the thermodynamic efficiency of a complex process (e.g., an electrical generating station or an automobile engine) is the ratio of the useful work obtained for a specified change of state to the maximum useful work obtainable with the ambient temperature To and pressure Pa. Here by useful work v.e mean the total work done by the system less the work done in expansion of the system boundaries against the ambient pressure. 

The application of the formal macroscopic theory to transformation processes in open systems is based on the formulation of balance equations for a number of conserved quantities and an additional thermodynamic constraint allowing the formulation of a useful efficiency measure. 

In eqn. (20) are replaced by the respective Ah .. As was already indicated the enthalpy efficiency does not have the fundamental properties of the thermodynamic efficiency as the restriction following from the application of the second law of thermodynamics (see eqn. (11 )) does not pose an upper limit to Hence, processes for which rii, exceeds unity can by no means be excluded. It can easily be shown that the efficiency measures developed above,... 

First Law of Thermodynamics - States that energy cannot be created or destroyed, but only changed from one form to another. First Law efficiency measures the fraction of energy supplied to a device or process that it delivers in its output. Also called the law of conservation of energy. 

This is our principal result for the rate of desorption from an adsorbate that remains in quasi-equihbrium throughout desorption. Noteworthy is the clear separation into a dynamic factor, the sticking coefficient S 6, T), and a thermodynamic factor involving single-particle partition functions and the chemical potential of the adsorbate. The sticking coefficient is a measure of the efficiency of energy transfer in adsorption. Since energy supply from the... 

It should be born in mind, however, that the activation parameters calculated refer to the sum of several reactions, whose enthalpy and/or entropy changes may have different signs from those of the decrystalUzation proper. Specifically, the contribution to the activation parameters of the interactions that occur in the solvent system should be taken into account. Consider the energetics of association of the solvated ions with the AGU. We may employ the extra-thermodynamic quantities of transfer of single ions from aprotic to protic solvents as a model for the reaction under consideration. This use is appropriate because recent measurements (using solvatochromic indicators) have indicated that the polarity at the surface of cellulose is akin to that of aliphatic alcohols [99]. Single-ion enthalpies of transfer indicate that Li+ is more efficiently solvated by DMAc than by alcohols, hence by cellulose. That is, the equilibrium shown in Eq. 7 is endothermic ... 

The guanine radical cations (G +) are detected by their reactions with water, which leads after treatment with piperidine or ammonia to selective strand cleavage [14]. A similar charge detection method was used by J.K. Barton, G.B. Schuster and I. Saito as described in their articles in this volume. The cleavage products were separated and quantified by gel electrophoresis. A typical example is shown in Fig. 7 where the GGG unit acts as a thermodynamic sink for the positive charge, and the efficiency of the charge transfer can be measured by the product ratio Pggg/Pg-... 

Equation (6) links, in a simple way, the thermodynamically important stability constants Kox and /Cred of a complex in different oxidation states with experimentally measurable redox potentials EH and EHa. Therefore it provides an easy way to obtain the ratio of KoxIKted, which is a theoretically useful parameter known as the binding enhancement factor (BEF). We propose that a better description for this ratio would be the reaction coupling efficiency (RCE) since binding by so-called molecular switches may be reduced or enhanced, depending upon the particular system involved. Equation (6) also allows the calculation of Kox if Kted is known or vice versa. 

Some of the compounds described in this chapter were studied for specific physical properties. Surface tension measurements with solutions of 9-16 in 0.01 M hydrochloric acid demonstrated that these zwitterionic X5Si-silicates are highly efficient surfactants.21 These compounds contain a polar (zwitterionic) hydrophilic moiety and a long lipophilic z-alkyl group. Increase of the n-alkyl chain length (9-15) was found to result in an increase of surface activity. The equilibrium surface tension vs concentration isotherms for 9 and 16 were analyzed quantitatively and the surface thermodynamics of these surfactants interpreted on the molecular level. Furthermore, preliminary studies demonstrated that aqueous solutions of 9-16 lead to a hydrophobizing of glass surfaces.21... 

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