Equations

Question 1

How is water pressure related to RH?

Answer 1

p[water] = RH * psat

Question 2

What is the equation for the flow rate of water out of a system?

Answer 2

mdot[water out] = mdot[water in] + mdot[water transport] + mdot[water reacted]

Question 3

What is the formula for mdot[water reacted] at a system level?

Answer 3

mdot[water reacted] = (M[water] * I * N[cells]) / (2 * F)

Question 4

For the equation Q = nI(E -V), what does n represent?

Answer 4

Number of cells.

Question 5

How to calculate mass flow rate of water across humidifier?

Answer 5

mdot = change in water fraction between exit and inlet * molar flow rate of air

Question 6

For the equation, E =-deltaG/(n*F), what does n represent?

Answer 6

Number of moles.

Question 7

Equation for deltaG wrt reactants and products?

Answer 7

DeltaG prod - deltaG react

Question 8

Efficiency based on HHV?

Answer 8

Eta = -deltaG/HHV

Question 9

If E is used to calculate a theoretical operating efficiency, how is the real efficiency calculated?

Answer 9

Use Vcell to find real deltaG rather than using E.

Question 10

Conversion of 1 L to m^3?

Answer 10

1 L = 10^-3 m^3

Question 11

For the equation for molar flow rate of water, what do lambdaC and lambdaA represent?

Answer 11

Water contents at cathode and anode.