Electrical energy efficiency

G and the maximum theoretical electrical energy efficiency values. We may notice the high e values for most reactions and for some even a thermal efficiency of over 100%. This rather surprising result arises due to the positive value of the entropy change of the reaction (T S term) concerned. The maximum values pertain to the situation of no load. As we may easily anticipate, the real world is much different and a real device will not achieve these terrific values under normal conditions of operation. These limitations arise from kinetic factors and we will briefly outline them next. [Pg.304]

Roy A, Watson S, Infield D (2006) Comparison of electrical energy efficiency of atmospheric and high-pressure electrolyzers, Int J Hydrogen Energy 31 1964-1979... [Pg.94]

Depending on their rating power fuel cells are electrochemical devices able to produce electric energy, together with heat (cogeneration systems), in a wide range of power with a similar electric energy efficiency (between 40% and 60%). This concerns... [Pg.386]

The electric-to-electric energy efficiency of the battery is very high. Thermal losses must be minimized by use of high-efficiency, preferably vacuum, insulation. [Pg.411]

Light-emitting diode—A semiconductor diode that converts electric energy efficiently into spontaneous and noncoherent electromagnetic radiation at visible and near-infrared wavelengths. [Pg.492]

Scenario I In this scenario, space heating is compensated by heat pump and thermal energy of fuel cell. Almost all thermal energy is consumed as shown in the Table VI.7. Usable energy efficiencies are 74.39 % for I. law and 52.2 % for II. law. Surplus electrical energy efficiencies from case-5 to case-8 are 48.62 %, 66.44 %, 60.48 % and 53 %, respectively (Table VI.7). Maximum used energy efficiencies are at case-5 where minimum unused electrical energy and values are 55.35 % for I. law and 29.99 % for n. law of thermodynamics (Table VI.8). [Pg.137]

The theoretical electrical energy efficiency (77") of a fuel cell can be defined as follows ... [Pg.13]

Practical Electrical Energy Efficiency of Fuel Cells... [Pg.43]

In Section 1,2,3, we discussed the thermodynamic efficiency of a PEM fuel cell as the ratio of theoretical electrical energy (AGceii) to the overall reaction heat energy (A//), This is the maximum efficiency that can be obtained from a fuel cell. However, in reality, fuel ceU efficiency is less than this ideal due to several losses in fuel cell performance. Therefore, the actual electrical energy efficiency (rje) should be written as in Eqn (1,72) ... [Pg.43]

Therefore, the fuel cell electrical energy efficiency expressed in Eqn (1.72) should be modified by Eqn (1.73) to give Eqn (1.74) ... [Pg.43]

In addition, if some hydrogen is lost due to hydrogen crossover or diffusion out of the fuel cell, the fuel cell efficiency will be further reduced. If we assume that the current generated by hydrogen loss is /loss and the actual current of the fuel cell is /ceii, then the electrical energy efficiency of a fuel cell can be further modified as in Eqn (1.75) ... [Pg.43]

The reaction utilizes electrical energy efficiently and occurs with 100% atom economy. [Pg.630]

The ideal efficiency AG/AH may be considered a measure of the thermodynamic reversibility of the reaction and depends only on the operating temperature and fuel used. It is typically between 80 and 100%. The voltage efficiency and fuel utilisation, as welt as the electrical energy efficiency, are useful measures for the success of the cell and stack design. [Pg.308]

Logan 2004 Rabaey et al. 2003). For comparison purposes, the electric energy efficiency for thermal conversion of methane is <40%. [Pg.50]

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