Flow chart of the PEM fuel cell model

The output voltage of the fuel cell is obtained by adding all the losses, which are activation, ohmic and concentration, to the Nemst Equation, which is reversible open circuit voltage. 

5 mgPtcm lower loadings are possible but would result in lower cell voltages) 

It is important that to remember that the equation (V.3) is only true when 

The total heat generation is the difference between the total power generation in the fuel cell at reversible condition (no losses) and electrical power generated at operation conditions with losses and this is the defined by the following equation  

In equation (V.8), all vapor content in hydrogen and oxygen turn to water in outlet. As a result, total heat generation considering enthalpies of all inlets is 

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The flow chart of the PEM fuel cell model is shown in the Figure V.l. 

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