Fuel cells principal types

The principal types of fuel cells under development are ... 

The first practical use of fuel cells was to provide auxiliary power in space vehicles. What was the principal reason for this choice Considering fuel cells runningon H2 and air 02, supplied by the re-forming of CH4 or CH3OH, discuss the various fuel cell types and suggest what applications will be made of re-formed H. (Bockris)... 

Table 3.3.1 Overview of the principal fuel cell types and their characteristics. Table adapted with permission from [1],... 

The six principal types of fuel cell have their own distinct characteristics and are at different stages in their development. Some of their individual features are given in Table 6.2. Of necessity, this is an oversimplified list that could be greatly refined in detail, especially with respect to the proposed applications, the scale of power generation and the nature of the fuel available. A concise, visual summary of the fuels that might be used in different fuel cells and the various possible future applications for these devices is given in Figure 6.20. 

The oxidation of acetyl CoA in the TCA cycle and the conservation of this energy as NADH and FAD(2H) is essential for generation of ATP in almost all tissues in the body. In spite of changes in the supply of fuels, type of fuels in the blood, or rate of ATP utihzation, cells maintain ATP homeostasis (a constant level of ATP). The rate of the TCA cycle, like that of all fuel oxidation pathways, is principally regulated to correspond to the rate of the electron transport chain, which is regulated by the ATP/ADP ratio and the rate of ATP utilization (see Chapter 21). The major sites of regulation are shown in Fig 20.12. 

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