On 24/12/16 16:11, T i m wrote:
On Sat, 24 Dec 2016 13:36:00 +0000, John Rumm
wrote:

On 24/12/2016 11:08, DerbyBorn wrote:
dennis@home wrote in news:585e54ca$0$1285$b1db1813
:

On 24/12/2016 10:07, DerbyBorn wrote:
Are immersion heaters as efficient as they could be? Could the tubular
element be improved upon - or doesn't it matter?


They convert 100% of the electricity to heat.
What efficiency would you like to improve?



I sort of knew all that - but could the dissapation be improved - I imagine
there is incredibly hot water next to the element - and the element itself
will be very hot. Spreading the 3kW over a larger area - could this result
in the element running cooler and the heat distributing better.

It does not really make any difference. If you stick 3kW in, then that
is what must come out. The harder you make it to get out, the hotter the
element will run, but eventually equilibrium will be reached.

Yup, *eventually* ... but what if there was some value (like recovery
time or minimising element scaling or failure due to overheating) that
could be gained by some minor design change?

Convection in the cylinder will take care of mixing the heated water.

Yes, in general it will (and does of course), but what if there were
still some improvements to be made, especially if they are cheap,
simple to implement and backwards compatible?

Like, many of our electric kettles have had just the element coil in
the bottom but at least one other had the element fused to a plate
covering the entire bottom of the kettle. Why would anyone bother to
do that if there was only one good design?

because its cheaper.

Cheers, T i m

Tim Tim, nasty and dim.