Thought Leadership

At the Speed of Heat

By Robin Bornoff

Many analogies exist relating heat flow to fluid flow. Oops, there’s one. A good electronics thermal design is one that gets the heat out from the heat sources quickly and the cold in to quench them quickly. Before I scoot off to sunny (though heavy rain is forecast) Devon for a family holiday I thought I’d leave you with this…

Thermal power dissipation is measured in Watts (W)

A Watt is a Joule/second (J/s)

A Joule is a Newton meter (Nm)

So Power = m/s  x N

A speed multiplied by a force.

Does this mean that there is a concept of a (steady state) ‘speed of heat’? If so what is it? These aren’t rhetorical questions by the way 🙂

31st July Hampton Court

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This article first appeared on the Siemens Digital Industries Software blog at