Volumetric Heat Capacity (VHC)
Volumetric heat capacity (VHC) describes the amount of heat a given volume of material requires for a temperature change. Outside a phase change, approximately Cvol = ρ · cp: density multiplied by specific heat capacity. The unit is J/(m³ · K).
How should this property be interpreted?
- A high value means that more heat is absorbed or released per unit volume and per kelvin of temperature change.
- For a uniform temperature change with approximately constant material properties, Q = ρ · cp · V · ΔT. A temperature difference of 1 K is equivalent to 1 °C.
- Material properties relate to the material, its state and the temperature range. A phase change additionally requires latent heat to be considered.
What does this mean for a shipping load?
Loads of equal volume can respond differently to the same heat input. Their geometry and heat transfer also play a role. VHC is therefore not a standalone indicator of protection duration. Thermal mass, by contrast, considers the total heat capacity of a specific load.
Technical references:
OpenStax: Temperature change and heat capacity