Calculate the heat needed for a phase change at constant temperature.
A phase change absorbs energy without any temperature rise. Water’s latent heat of vaporisation is about 2,260 kJ/kg — enough to raise the same water by more than 500 degrees if it were sensible heat instead. Latent heat is why boiling a pan dry takes far longer than bringing it to the boil, and why evaporative cooling is so effective.
Latent Heat
Q = m L, where L is the specific latent heat
Q = m L, where L is the specific latent heat A phase change absorbs energy without any temperature rise. Water’s latent heat of vaporisation is about 2,260 kJ/kg — enough to raise the same water by more than 500 degrees if it were sensible heat instead.
Latent heat is why boiling a pan dry takes far longer than bringing it to the boil, and why evaporative cooling is so effective.
This calculator takes 4 inputs: Mass, Specific latent heat, Available power, Specific heat capacity for comparison. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.