Electrolyzer (rigorous) simulation

water feed -> H2 (Butler-Volmer/Nernst cell); fuel-cell mode: H2 -> water

Governing equations

The exact equations the solver works for a electrolyzer (rigorous) — the same math shown in the app's "Theory" panel, not a black box.

$V_{cell}$

actual cell voltage [V] — the sum below is why a real stack needs more than the thermodynamic minimum

$E_{rev}$

reversible (Nernst) voltage [V]

$\eta_{act}$

activation overpotential — the kinetic penalty at the electrodes

$\eta_{ohm}$

ohmic overpotential — resistance of membrane and hardware

$\eta_{conc}$

concentration overpotential — mass-transport limitation at high current

$i$

current density [A/m²]

$i_0$

exchange current density [A/m²]

$i_{cross}$

crossover current density (gas permeating the membrane)

$\alpha$

charge-transfer coefficient

$R_{area}$

area-specific resistance [Ω·m²]

$I$

total current [A]

$F$

Faraday constant

$\eta_F$

Faradaic efficiency — the fraction of current that actually makes product

$R$

gas constant

$T$

temperature [K]

Parameters

current_density [A/m^2]; optional area [m^2], n_cells, preset 'pem'|'alkaline', mode 'electrolysis'|'fuel_cell', pressure [Pa], temperature [K], and per-electrode overrides (i0_anode/i0_cathode, alpha_*, r_area, i_lim, crossover_current)

Example flowsheets that use it