Re: [Amc-list] ELECTRO-RAMBLER =revisited=

[Tom Jennings <tomj@xxxxxxx>]

On Fri, 27 Apr 2007, Swygert, Francis G MSgt 436 CES/CECM wrote:

> Electric resistance heat is very inefficient.

Hmmm actually it's 100% efficient. What's in-efficient is
creating and storing the electricity. A 100V, 1A heater produces
precisely 100 watts of heat with no loss -- the heat IS the loss!

A gallon of hot water stores a lot of heat energy in it's
mass. It's a different unit of measure though, it stores watts
* time.


A 100watt heater made of a short piece of wire makes 100 watts
of heat, which might take the form of a small column of 500
degree air. Put that same 100 watt heater in a gallon of water
and it raises the temperture (some number). If the air-heater,
and the water-heater, are run for the same number of seconds,
the same amount of heat energy is generated, and the "cost"
is the same -- measured in watt-seconds.

This part is interesting and counter-intuitive until you actually
do it -- if you were to actually set the up and measure it,
and plot the temperature on paper as a function of time,
(temp vertical, time horizontal) as a graph (wire very hot,
not very long; water warm, for a long time) you'll find that
the area enclosed by the curve on the paper will be EXACTLY
THE SAME... it's called Integration.

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