Oil heat capacity
When choosing industrial oil, the client’s foremost concern is the oil’s performance characteristics. They allow the user of the oil to fully evaluate the oil with regards to its industrial application.
In previous articles we have discussed such specificatsion as viscosity, pour point, flashpoint and density. Another performance characteristic to consider is the oil’s heat capacity which usually receives little attention.
So what is heat capacity of oil and why is it important to know when selecting oil? An object’s heat capacity oil describes the amount of heat required to change the temperature of that object by a certain amount. For oil, it is a physical parameter that is defined by the ratio of the amount of heat received by the oil to the increase of the oil’s temperature. In the international convention, the unit of oil heat capacity is J/K.
In practice it is more convenient to work with the specific heat of industrial oil which is the ratio of oil heat capacity to a quantity of oil. In the international measurement system SI, it is recommended to measure this in J/kg×K). In certain cases it is possible to use calories per kilogram per degree of Kelvin, or Joules per kilogram per degree Centigrade (J/kg×ºС).
If the oil has high heat capacity oil, it can efficiently dissipate heat from the different parts of the machinery it is circulating in.
Oil specific heat capacity heat is not a constant. It depends on the temperature and is usually in the range of 1.67-2.5 kJ/kg×ºС.
By comparison, heat capacity of clean water is 4.218 kJ/kg×ºС, gasoline – 2.09 kJ/kg×ºС, kerosene – 1.88 kJ/kg×ºС, goudron – 2.09 kJ/kg×ºС, liquid paraffin – 2.13 kJ/kg×ºС, liquid ammonia – 4.73 kJ/kg×ºС.