What, exactly, is the heat capacity of a material, and how does it affect cooling of a circuit board or in a data center? Heat capacity is an intrinsic characteristic of a material, and refers to the amount of heat, measured in joules or calories, that must be input into a material in order to raise its temperature by a certain amount. Different materials hold different amounts of heat (again, measured in joules or calories), even when they’re at the same temperature. Think of heat capacity as the “thermal mass” of a material, if you will.
A heat capacity means that a relatively small mass of fluid carries a large amount of energy away, per unit temperature drop. A fluid with a lower heat capacity would need a greater temperature drop or greater flow rate with more heat exchanger surface to transfer the same amount of heat away.
Sundin, D. (2013). Discussion on Specific Heat. Retrieved May 4, 2014, from http://dsiventures.com/2013/09/04/discussion-on-specific-heat/