heat-transfer-1d

Steady-state, one-dimensional heat transfer. The three modes — conduction, convection, radiation — plus the "thermal circuit" trick of adding resistances in series to model a composite wall.

No dependencies, SI units (W, m, K).

The three modes

import {
  conductionRate,   // Fourier:  q = k A ΔT / L
  convectionRate,   // Newton:   q = h A ΔT
  radiationRate,    // grey body: q = εσA(Ts⁴ − Tsurr⁴), T in kelvin
} from 'heat-transfer-1d';

conductionRate(0.8, 2, 20, 0.1);   // 320 W
convectionRate(25, 3, 10);         // 750 W
radiationRate(1, 1, 1000, 0);      // ~56.7 kW

Thermal circuits

Treat each layer / film as a resistance and add them up. Then the heat flow is just the temperature drop divided by the total resistance — Ohm's law for heat.

import {
  convectionResistance,
  conductionResistance,
  circuitHeatFlow,
  overallU,
  seriesResistance,
} from 'heat-transfer-1d';

const A = 1;
const R = [
  convectionResistance(10, A),   // inside film
  conductionResistance(0.2, 0.5, A), // wall
  convectionResistance(40, A),   // outside film
];

circuitHeatFlow(30, ...R);            // ~57.1 W for a 30 K drop
overallU(seriesResistance(...R), A);  // overall U value

Notes

• Radiation temperatures must be absolute (kelvin). The library will happily compute nonsense if you pass celsius.
• The wall temperature profile assumes constant conductivity and no internal heat generation, so it is linear.
• Radial (cylindrical / pipe insulation) conduction is not implemented yet.

License

Released into the public domain under the Unlicense.