Circulator, isentropic

The above relate to Figure A.2, which shows an enhanced version of Figure A.l, designed to allow operation of the cell at any selected high temperature and pressure. Isentropic circulators are incorporated to generate the increased conditions. The cell generates heat which is passed without temperature difference to a Carnot cycle to generate power, a reversible process free from the irreversibility of combustion. 

I I I Isentropic Circulator or Isothermal Concentration Cell Figure A.l High-pressure and high-temperature fuel cell... 

The details of the isothermal and isentropic circulator work of Figure A.2 are given in the introduction of this book, points 14 and 15, together with the underlying theory of the associated Carnot cycle, as... 

As the electrical work of the electrochemical reaction in Figure A.2 declines with increasing temperature, there is a corresponding increase of Carnot work and a change of the substantial circulator power. At standard conditions the isentropic circulators are redundant, as is the Carnot cycle. 

The three isothermal circulators in Figure A.l are clearly all expanders, producing power. The isentropic circulators and the Carnot cycle are redundant, having zero temperature difference. The circulator power added to the standard conditions AG of Table A.2 will give the chemical exergy of the two fuels, CO and H2. 

The circulator power now has isentropic and isothermal components. For the isentropic machines,... 

Much more would have to be done in the laboratory to investigate the possibility of a practical Faradaic reformer choice of electrode and electrolyte the possibility of irreversible electrode reactions the need for an electrocatalyst. It can be concluded safely that a basis for fuel chemical exergy efficiency calculations exists, namely the Faradaic reformer, fuel cell combination at standard conditions. The reduced performance of the reformer fuel cell combination, at temperature and pressure, can be left as a major exercise for the reader by adding isentropic circulators and a Carnot cycle to Figure A.2. 

The equilibrium of a hydrogen or carbon monoxide fuel cell operating at high temperature and pressure is defined using a flow sheet, which connects the cell to a fuel store at standard conditions, and to the environment, via combined isentropic and isothermal circulators and a Carnot cycle. 

Figure 3.25. Schematic representation of the wave-driven transport circulation (solid lines with arrows) in the winter stratosphere. The shaded area represents the surf zone where meridional mixing associated with wavebreaking is taking place. Light dashed lines represent isentropes. The heavy dashed line shows a constant mixing ratio surface of a long-lived tracer. The dotted line represents the tropopause. Adapted from Holton and Alexander (2000).

Plate 4. Ozone volume mixing ratio on the 417 K isentropic surface (approximately 16 km altitude) on 31 December 1991. Filaments of ozone-rich air pulled from the polar region are irreversibly mixed into the mid-latitude surf zone. The net effect is to weaken the latitudinal ozone gradient created by the Brewer-Dobon circulation. From NASA. 

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