Does Wind Chill Affect Machines?

It is well known that the wind-chill factor can lower the effective temperature experienced by human beings by many degrees, depending on the velocity of the wind. The debatable question often arises, "Does it also affect machines?"

Many of us have had the experience of sitting in a car at a stoplight with clear windows, only to have them fog up again when the car starts moving. More often than not, this is a result of snow that was on the hood being sucked through the car's heater system; but there is another factor involved as well, and that is wind chill.

If we were to take an engine block and install it on mounts in the middle of a field for the winter, it would make no difference in the temperature of that engine block if the wind blew or not. It would remain at the ambient temperature of the air surrounding it, whether or not the air was moving. However, if we were to start up that engine and let it warm up, there would be a great deal of difference in the block temperature depending on whether or not the wind was blowing.

Any object that creates its own internal heat will find that heat is removed from it faster if the air around it is moving. It is simply a matter of heat transfer--the "conveyor belt" of moving air (convection) will snatch the heat away much faster than if it were still.

So the answer to the question is yes. Wind chill does affect machines, but only if they are at a temperature above that of the surrounding air.