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Default Power cost of idle electric water heater

In misc.industry.utilities.electric wrote:
| wrote:
|
|A larger tank should help, given a smaller surface to lose heat from...
|
| Larger tanks have less surface?

As the volume goes up proportionally to the cube of a dimension, the surface
area through which heat can escape goes up only proportionally to the square
of a dimension, assuming a constant shape (e.g. ratio between diameter and
length for a cylinder). A tank which doubles in size for all dimensions
will have 4 times the surface area (where the heat escapes), and 8 times the
volume (where heat is held). The heating surface may be similarly limited,
so such a tank could also be slower to heat up (because the heating elements
would probably be limited to at most 4 times the wattage, and for some other
reasons, not even that much). So much of this depends on the designs.

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| Phil Howard KA9WGN |
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| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
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