Intrinsic conversion efficiency

In the last decade, much effort has been expended on developing novel thermoelectric (TE) materials of increased intrinsic conversion efficiency [9] at same time, the design of the system architecture plays an important role in optimizing the thermal exchange and in maximizing the conversion performance [10]. For that reason, in this section we report an example of a detailed thermal management analysis with the heat re-flowed in the system. 

However, there is something so important and fundamental in this different way of converting the energy released in a chemical reaction to work that it is worth a more detailed inquiry on a molecular level, concerning the difference in intrinsic conversion-efficiency maxima between thermal and electrochemical reactions. 

To be used in x-ray intensifying screens, rare earth phosphors must also have high conversion efficiencies (nc Figure 1) in addition to high intrinsic absorptions of x-rays and suitable emission characteristics. The several rare earth phosphors listed in Table I have conversion efficiencies from about 10% for La202S Tb to about 20% for LaOBr Tb (5,, ) as compared to about 6% for CaWOi. ... 

Conversion efficiencies as high as 20% might be achieved by the end of the decade if good-quality intrinsic alloys can be developed for stacked junction cells (see Section 8). Wu and Williams (1983) have estimated a theoretical limit of 38% for a structure employing two stacked junctions, but their calculations did not include the effect of tail states. Kuwano et al. (1983) have estimated that the maximum practical efficiency is -24% for a structure with three stacked junctions. 

In an ideal electrochemical cell, the Gibbs energy of reaction is converted to electrical energy, then the intrinsic maximum energy conversion efficiency of an electrochemical cell is... 

On the other hand, all efforts to devise a process for the continuous conversion of heat completely into work or into mechanical or electrical energy have failed. Regardless of improvements to the devices employed, conversion efficiencies do not exceed about 40 percent. These low values lead to the conclusion that heat is a form of energy intrinsically less useful and hence less valuable than an equal quantity of work or mechanical or electrical energy. 

From such basic calculations, it becomes clear that the intrinsic ORR activity at the Pt/recast ionomer interface is sufficient to achieve quite high performances in PEFCs in terms of desired combinations of high energy conversion efficiency and... 

In conclusion, CEC has great potential in separation technology. Our theoretical model as well as many published practices in CEC show clearly that the benefit of combining electrophoresis and partitioning mechanisms in CEC is the increase in selectivity for the separation. The intrinsic difference in formation constants is critical, but the experimental factors, such as electric field or the stationary and mobile phases, can also contribute to the improvement of the overall enantioselectivity via increasing the conversion efficiency. However, only when both electrophoretic and partitioning mechanisms act in the positive effects, can high overall enantioselectivity in CEC be obtained. 

The combination of high intrinsic interfacial activity at the Pt/ionomer interface and effective catalyst dispersion also provides a key for high energy-conversion efficiency. The overall efficiency of a fuel cell converting fuel to electric power at some voltage, V/gU, across the load, is calculated as ... 

Power conversion efficiency is used to evaluate the photovoltaic performances of solar cells, which is defined by dividing the maximum output power with incident power. The parameters of polymer solar cell performance including open-circuit voltage (Vbc). short-circuit current density (/sc) are originated firom the intrinsic properties of the photoactive polymer. For detailed information of the relationship between polymer properties and solar cell performance will be discussed in the following sections. 

---