Thermal capacity is the heat required to raise a body one unit or
degree of temperature. Thermal capacity and heat capacity are synonymous.
The SI unit is J kg-1 degree C-1
Specific heat is the ratio of the thermal capacity of the substance
to that of water (at 15 degree C). Therefore, thermal capacity is
numerically equal to specific heat. Specific heat is a function of
fluid structure and density. In HDL, specific heat is used in the
calculation of heat transfer, temperature rise, and other thermal
factors in an oil film. In Reference 8, the thermal capacity of three
materials was given as:
Material
Thermal Capacity (J kg-1 degree C-1)
Water
4184
Mineral Oil
1966
Steel
460
Therefore, more heat is required to raise the temperature of 1 kilogram
of water and oil than is required for steel.
Specific heat is measured using ASTM D 3947. A sample is introduced
into a differential scanning calorimeter by means of a hermetically
sealed sample cell. The cell is placed on a thermocouple in a controlled
environment programmed to increase temperature at a specific rate.
This allows the calculation of the specific heat of the oil.
For more information call 1-888-HERGUTH (437-4884)