Smart Textiles

PCM Thermal Buffer Capacity & Duration Calculator

PCM buys minutes, not degrees. Once it has melted it is just a heavier garment.

PCM Loading In the garment
g/m²
m²
J/g
J/g·K
K
Heat Load Wearer
W

Buffering Duration

— min

Before the PCM is fully melted and stops absorbing

Capacity

Latent Heat Capacity
— kJ
Sensible Heat Capacity
— kJ
Total Buffer Capacity
— kJ
PCM in the Garment
— g
Capacity per m²
— kJ/m²

Buffering only works if the PCM can also re-solidify — a garment that never cools below the melt point gives one cycle and no more. The excess metabolic figure is the heat the body cannot otherwise shed, not total metabolic output; taking the larger number will overstate the demand and understate the duration.

PCM Thermal Buffer Capacity & Duration Calculator — free, with the formula and a worked example, at Textile School.