Free energy conversion efficiency

Fuel Cell Efficiency The theoretical energy conversion efficiency of a fuel cell ° is given by the ratio of the free energy (Gibbs function) of the cell reaction at the cell s operating temperature AG to the enthalpv of reaction at the standara state AH°, both quantities being based on a mole of fuel ... 

In a bulk-heterojunction photovoltaic cell with methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as an electron acceptor, alternating copolymer 19 (Fig. 9), derived from 2,7-fluorene and 2,5-dithienylsilole, can show impressive performance as the electron donor.31 In a device configuration of ITO/PEDOT/active layer/Ba/Al, the dark current density—bias curve shows a small leakage current, suggesting a continuous, pinhole-free active layer in the device. Under illumination of an AM 1.5 solar simulator at 100 mW/cm2, a high short-circuit current of 5.4 mA/cm2, an open-circuit voltage of 0.7 V, and a fill factor of 31.5% are achieved. The calculated energy conversion efficiency is 2.01%. 

Maximum energy conversion efficiencies of (/ lax = 0.1086 have recently been measured and verified for dye-sensitized regenerative cells illuminated with air mass 1.5 simulated solar irradiation [27]. The efficiency of photoelectrosynthetic cells must also include contributions from the free energy stored in the chemical products of the reduction and oxidation reactions. 

Carbon dioxide can be electrochemically reduced to useful products under mild conditions. However, the energy conversion efficiency, defined as the ratio of the free energy of the products obtained in electrochemical CO2 reduction and that consumed in the reduction, would be roughly 30 to 40%. Such a low efficiency may discourage practical application of CO2 reduction in the very near future. However, the significance of the CO2 reduc-... 

The molten carbonate fuel cell systems have mie of the highest energy conversion efficiency systems for distributed generation, and reliability is improving. Furthermore, they are free from rare elements such as noble metals and rare earth metals. Therefore, further effort and support to improve reliability and market entry will be required for real commercialization. 

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