On Sat, 24 Dec 2016 16:02:31 +0000, dennis@home
wrote:

On 24/12/2016 14:11, T i m wrote:

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?

The flat plate ones are so you can boil less water and hence may save
energy.
However unless they are insulated underneath or the plate is thick they
will lose a bit more energy out of the base than a kettle with an
immersed element.

This was a conventional electric kettle but instead of the element
just being a flat spiral of sorts, said element was bonded to a flat
plate that formed a dummy inner 'bottom' to the (plastic) kettle.

Presumably the plate spread the heat over a larger area but looked as
if there would be less heat transferred between the actual element
itself (still visible under the plate) and the water.

Butanyroadup, the OP was wondering if a std immersion heater could be
improved upon and I think it can (most things can, hence 'new and
improved' versions that are 'better' that the originals). However, I'm
not sure exactly how much quicker the cylinder would recover (for the
same 'rating' of heater, all be it a cooler one may draw / deliver
more energy because of a lower internal resistance), how much longer
it would last (because it ran cooler) and how much better it might
resist furring up (because it ran cooler).

On a similar vein, when Dad was on 'tankers' he said that when
carrying pitch (or tar, I can't remember) they used steam from the
boilers, passed though pipes running though the hold to keep the cargo
'liquid'.

If for any reason the cargo was allowed to cool to a point where it
would harden, the heat from the steam pipes wasn't sufficient to get
it all to melt again because of insufficient conduction through the
cargo and hence no convection (and it would have to be dug out).

Now, *maybe* if the pipes were closer together or had some sort of
'finning' that would carry the heat further into the cargo, it could
re-melt it all again?

Cheers, T i m

"DerbyBorn" wrote in message
.222...
Are immersion heaters as efficient as they could be? Could the tubular
element be improved upon - or doesn't it matter?

It mostly doesn’t matter, because there isnt anywhere else for the heat to
go.

"DerbyBorn" wrote in message
2.222...
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

Sort of, that's why you can hear the kettling with the worst of them.

- and the element itself
will be very hot. Spreading the 3kW over a larger area - could this result
in the element running cooler

Yes.

and the heat distributing better.

No. Basically there is nowhere else for the heat to go but into the water.

"Dave Plowman (News)" wrote in message
...
In article ,
DerbyBorn wrote:
Are immersion heaters as efficient as they could be? Could the tubular
element be improved upon - or doesn't it matter?

Since the only thing generated by the electricity they use is heat, where
can it go other than into the water?

(It might also produce 'light' like UV or infra red

Which still ends up in what is being heated.

- but in such a tiny amount as can be disregarded.)

On 24/12/16 16:03, T i m wrote:
On Sat, 24 Dec 2016 15:47:04 +0200, The Natural Philosopher
wrote:

snip arrogant TNP left-brain thinking

Do you really care whether your tank reaches thermal equilibrium in 3
minutes or 4 minutes?

1) I didn't post the question.

2) I don't have a hot water cylinder

3) I understand that people (other than you) can have such 'right
brained' discussions.

4) You aren't obliged to join in.

Cheers, T i m

actually its you with the Arrogant leftybrain thinking.

I am an engineer. I spent over ten years at school and university
learning this stuff and over 40 years doing it for a living. The thread
is based in cacamonkey notions that are ******** from the word go.

If you want to play bandar log wanking off about stuff you don't even
begin to understand, be my guest.

I'll just there and watch the industrial society engineers built to keep
you alive disintegrate because arseholes like you actually think they
understand something about phsyics and science.

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.

On 24/12/16 16:13, T i m wrote:
On Sat, 24 Dec 2016 15:38:59 +0200, The Natural Philosopher
wrote:

On 24/12/16 13:08, 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.

No.

But you don't explain 'why not' (for some reason), however
insignificant any gains may be seen ITRW.

Only improvement would be to thermally isolate element from incoming
mains wires by eg. using RF or magnetic coupling through some insulation.

We were ignoring any such losses (by 'we' I mean the OP and any other
right brainers). ;-)


in which case the answer is Yes,immersion heaters are as efficient as
they could be .

Full stop period end of discussion stopwanking now.

Cheers, T i m

On 24/12/16 16:15, T i m wrote:
On Sat, 24 Dec 2016 15:37:02 +0200, The Natural Philosopher
wrote:

On 24/12/16 12:07, DerbyBorn wrote:
Are immersion heaters as efficient as they could be? Could the tubular
element be improved upon - or doesn't it matter?

they are 100% efficient more or less. Certainly in the high 90s.

Heat loss is seldom through the element, so its more about heatloss from
the tank itself.

Where did the OP mention heat loss?

In the word 'efficiency' you stupid ****.


You really don't get the whole concept of 'Just wondering' do you? ;-(

Cheers, T i m

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?



I suppose you could improve on the design to allow it to get the heat
away quicker - .... by having a load of fins - and therefore create
surface area in contact with the water.
Wouldn't make conversion of electricity to heat any more efficient.

Cost involved probably not worth any gain.

On Sat, 24 Dec 2016 21:59:41 +0200, The Natural Philosopher
wrote:

On 24/12/16 16:03, T i m wrote:
On Sat, 24 Dec 2016 15:47:04 +0200, The Natural Philosopher
wrote:

snip arrogant TNP left-brain thinking

Do you really care whether your tank reaches thermal equilibrium in 3
minutes or 4 minutes?

1) I didn't post the question.

2) I don't have a hot water cylinder

3) I understand that people (other than you) can have such 'right
brained' discussions.

4) You aren't obliged to join in.

Cheers, T i m

actually its you with the Arrogant leftybrain thinking.

I am an engineer. I spent over ten years at school and university
learning this stuff and over 40 years doing it for a living. The thread
is based in cacamonkey notions that are ******** from the word go.

Again you have been whooshed mate. The bit you are still getting wrong
is nothing to do with engineering but people. Not unexpected of
course, you simply can't help it.

snip leftbrain insult attempt

I'll just there and watch the industrial society engineers built to keep
you alive disintegrate because arseholes like you actually think they
understand something about phsyics and science.

Aww bless, you just do that then ... while some of are happy *discuss*
all sorts of things that are completely incomprehensible to you. ;-)

But you aren't able to *discuss* are you, it's your way or the highway
/ insults. ;-(

Cheers, T i m

On Sat, 24 Dec 2016 22:00:36 +0200, The Natural Philosopher
wrote:

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.

Bingo. And thanks for playing (I hopped you would get there in the
end). ;-)

snip more childish insults

Cheers, T i m

On Sat, 24 Dec 2016 22:01:51 +0200, The Natural Philosopher
wrote:

On 24/12/16 16:13, T i m wrote:
On Sat, 24 Dec 2016 15:38:59 +0200, The Natural Philosopher
wrote:

On 24/12/16 13:08, 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.

No.

But you don't explain 'why not' (for some reason), however
insignificant any gains may be seen ITRW.

Only improvement would be to thermally isolate element from incoming
mains wires by eg. using RF or magnetic coupling through some insulation.

We were ignoring any such losses (by 'we' I mean the OP and any other
right brainers). ;-)


in which case the answer is Yes,immersion heaters are as efficient as
they could be .

So you say?

Full stop period end of discussion

So you say? Killfile stopped working? Could you fix it please as it
was much better having to hear all your confused attempts at replies
to questions no one asked. ;-(

snip leftbrain misunderstanding

Cheers, T i m

On Sun, 25 Dec 2016 06:09:43 +1100, "John" wrote:



"DerbyBorn" wrote in message
. 92.222...
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

Sort of, that's why you can hear the kettling with the worst of them.

- and the element itself
will be very hot. Spreading the 3kW over a larger area - could this result
in the element running cooler

Yes.

and the heat distributing better.

No. Basically there is nowhere else for the heat to go but into the water.

So, are you saying that a 'kettling' element *will* be transferring
it's energy to the water as effectively as one with say twice the
surface area that wasn't kettling? (straight question).

So we aren't talking directly about a loss of energy here, but a loss
of efficiency (because of kettling and other variables).

Cheers, T i m

On Sat, 24 Dec 2016 22:02:31 +0200, The Natural Philosopher
wrote:

On 24/12/16 16:15, T i m wrote:
On Sat, 24 Dec 2016 15:37:02 +0200, The Natural Philosopher
wrote:

On 24/12/16 12:07, DerbyBorn wrote:
Are immersion heaters as efficient as they could be? Could the tubular
element be improved upon - or doesn't it matter?

they are 100% efficient more or less. Certainly in the high 90s.

Heat loss is seldom through the element, so its more about heatloss from
the tank itself.

Where did the OP mention heat loss?

In the word 'efficiency' you stupid

snip

Do you realise it's a sign of weakness if you are unable to explain
things properly (not that you ever could now you have dug such a big
hole) without resorting to expletives and insults?

See, if you weren't such a 'perfect engineer' you would have realised
that the OP's question was *nothing* to do with overall system losses
but *all* to do with how efficiently the heating element transferred
it's energy to the water.

In fact, let's recap exactly what he said and see if the penny drops
with you yet ... "Are immersion heaters as efficient as they could be?
Could the tubular element be improved upon - or doesn't it matter?

Go on, have another go. ;-)

Cheers, T i m

On Sat, 24 Dec 2016 20:02:31 +0000, rick
wrote:

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?



I suppose you could improve on the design to allow it to get the heat
away quicker - .... by having a load of fins - and therefore create
surface area in contact with the water.

That is what I was reflecting.

Wouldn't make conversion of electricity to heat any more efficient.

So, if we put a 100kW heater in there and had it on for 1 second,
would the water end up as hot as if we put a 10kW heater in there and
had that on for 10 seconds? I'm not talking 'theoretically, I'm
talking real world here?

The (/my) 'big question' is that if (say) the heater element get's
sufficiently hot as to start to boil the surrounding water, *does* the
heat get carried into the water as effectively as if it wasn't
boiling?

If the answer is no, then you could see how if you increased the
surface are of the heater you decrease the energy / area and could
take it down to a level where there was no kettling.

Cost involved probably not worth any gain.

No, quite, but that wasn't really part of the question. ;-)

Cheers, T i m

On 24/12/2016 20:34, T i m wrote:

So, are you saying that a 'kettling' element *will* be transferring
it's energy to the water as effectively as one with say twice the
surface area that wasn't kettling? (straight question).

They will both transfer the same amount of heat for the same power
consumption/

Of course you can make them better for some values of better.

Like you could use diamond as an insulator as it conducts heat very well.

You could put stainless steel tails on as they don't conduct heat very well.

etc.


However they won't happen until they are cheap.

"T i m" wrote in message
...
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 you needed to justify what they were paying you to design stuff.

"The Natural Philosopher" wrote in message
news
On 24/12/16 16:03, T i m wrote:
On Sat, 24 Dec 2016 15:47:04 +0200, The Natural Philosopher
wrote:

snip arrogant TNP left-brain thinking

Do you really care whether your tank reaches thermal equilibrium in 3
minutes or 4 minutes?

1) I didn't post the question.

2) I don't have a hot water cylinder

3) I understand that people (other than you) can have such 'right
brained' discussions.

4) You aren't obliged to join in.

Cheers, T i m

actually its you with the Arrogant leftybrain thinking.

I am an engineer. I spent over ten years at school and university learning
this stuff and over 40 years doing it for a living. The thread is based in
cacamonkey notions that are ******** from the word go.

If you want to play bandar log wanking off about stuff you don't even
begin to understand, be my guest.

I'll just there and watch the industrial society engineers built to keep
you alive disintegrate because arseholes like you actually think they
understand something about phsyics and science.

Even more pathetically bitter and twisted than usual.

"T i m" wrote in message
...
On Sat, 24 Dec 2016 22:00:36 +0200, The Natural Philosopher
wrote:

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.

Bingo. And thanks for playing (I hopped you would get there in the
end). ;-)

Why are you hopped up ?

snip more childish insults

Cheers, T i m

"T i m" wrote in message
...
On Sun, 25 Dec 2016 06:09:43 +1100, "John" wrote:



"DerbyBorn" wrote in message
.92.222...
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

Sort of, that's why you can hear the kettling with the worst of them.

- and the element itself
will be very hot. Spreading the 3kW over a larger area - could this
result
in the element running cooler

Yes.

and the heat distributing better.

No. Basically there is nowhere else for the heat to go but into the water.

So, are you saying that a 'kettling' element *will* be transferring
it's energy to the water as effectively as one with say twice the
surface area that wasn't kettling?

Yes, because there is nowhere else for the heat to go.

(straight question).

Just as well, I don't like bent questions.

So we aren't talking directly about a loss of energy here, but
a loss of efficiency (because of kettling and other variables).

That isnt loss of efficiency, all the heat still ends up in the water.

"T i m" wrote in message
...
On Sat, 24 Dec 2016 20:02:31 +0000, rick
wrote:

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?



I suppose you could improve on the design to allow it to get the heat
away quicker - .... by having a load of fins - and therefore create
surface area in contact with the water.

That is what I was reflecting.

Wouldn't make conversion of electricity to heat any more efficient.

So, if we put a 100kW heater in there and had it on for 1 second,
would the water end up as hot as if we put a 10kW heater in there and
had that on for 10 seconds?

Depends on the detail of the construction. You
might well get flash evaporation of all the water
and the cylinder going bang in that situation.

I'm not talking 'theoretically, I'm talking real world here?

Me too.

The (/my) 'big question' is that if (say) the heater element get's
sufficiently hot as to start to boil the surrounding water, *does* the
heat get carried into the water as effectively as if it wasn't boiling?

Nope, some escapes as steam.

If the answer is no, then you could see how if you increased the
surface are of the heater you decrease the energy / area and
could take it down to a level where there was no kettling.

Kettling is different to boiling the water. You don't
actually get steam with kettling, the bubbles collapse
and that is what causes the noise. And that noise is a
marginal loss of efficiency.

And I can see steam coming from the turnip's ears as I type...

Cost involved probably not worth any gain.

No, quite, but that wasn't really part of the question. ;-)

Corse it was, cost is always part of efficiency, stupid |-(

In article , Andy Burns
writes
DerbyBorn wrote:

dennis@home wrote:

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

You could put fins on the element, it would speed the recovery time.

Collapsible to get them through the small hole.
--
bert

In article , Huge
writes
On 2016-12-24, John wrote:

[31 lines snipped]

No. Basically there is nowhere else for the heat to go but into the water.

And into the air in the airing cupboard.


Via the water.
--
bert

In article , T i m
writes
On Sat, 24 Dec 2016 20:02:31 +0000, rick
wrote:

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?



I suppose you could improve on the design to allow it to get the heat
away quicker - .... by having a load of fins - and therefore create
surface area in contact with the water.

That is what I was reflecting.

Wouldn't make conversion of electricity to heat any more efficient.

So, if we put a 100kW heater in there and had it on for 1 second,
would the water end up as hot as if we put a 10kW heater in there and
had that on for 10 seconds? I'm not talking 'theoretically, I'm
talking real world here?

The (/my) 'big question' is that if (say) the heater element get's
sufficiently hot as to start to boil the surrounding water, *does* the
heat get carried into the water as effectively as if it wasn't
boiling?

No Go watch a saucepan of water coming to the boil.
If the answer is no, then you could see how if you increased the
surface are of the heater you decrease the energy / area and could
take it down to a level where there was no kettling.

Cost involved probably not worth any gain.

No, quite, but that wasn't really part of the question. ;-)

Cheers, T i m


--
bert

On Sat, 24 Dec 2016 14:22:48 +0000 (GMT+00:00), Biggles wrote:

Who has those these days?


Anyone who wants an alternative way of heating the water if the
boiler fails, or prefers to have an airing cupboard, or needs a
store of hot water to cope with parallel demands (e.g. from
several showers in use simultaneously).

Aren't the hot water cylinders supplied with integrated insulation
round them, as one package? No separate 'bulky' insulation.

On Sat, 24 Dec 2016 23:28:59 +0000, bert wrote:

In article , Andy Burns
writes
DerbyBorn wrote:

dennis@home wrote:

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

You could put fins on the element, it would speed the recovery time.

Collapsible to get them through the small hole.

I'm not sure 'collapsible' and 'good thermal conductivity are normally
found in the same sentence but if the heater was left at the same
basic extended 'U' design, you could still increase the surface area
by simply joining the two 'runs' together with a flat sheet (and the
stat will simply run down the side of that) and so it will easily fit
down the same hole in the cylinder.

Cheers, T i m

On Sun, 25 Dec 2016 09:27:37 +1100, "Rod Speed"
wrote:

snip

Bingo. And thanks for playing (I hopped you would get there in the
end). ;-)

Why are you hopped up ?

Can you be on just one can of 'Bud'? ;-)

Cheers, T i m

On Sun, 25 Dec 2016 08:39:14 +1100, "Rod Speed"
wrote:

snip

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 you needed to justify what they were paying you to design stuff.

Quite ... so I guess someone must have done that for us to get a
kettle designed like that?

Cheers, T i m

"T i m" wrote in message
...
On Sun, 25 Dec 2016 09:27:37 +1100, "Rod Speed"
wrote:

snip

Bingo. And thanks for playing (I hopped you would get there in the
end). ;-)

Why are you hopped up ?

Can you be on just one can of 'Bud'? ;-)

Yep, if you are an asian.

On Sun, 25 Dec 2016 09:31:05 +1100, "John" wrote:

snip

So, are you saying that a 'kettling' element *will* be transferring
it's energy to the water as effectively as one with say twice the
surface area that wasn't kettling?

Yes, because there is nowhere else for the heat to go.

(straight question).

Just as well, I don't like bent questions.

;-)

So we aren't talking directly about a loss of energy here, but
a loss of efficiency (because of kettling and other variables).

That isnt loss of efficiency, all the heat still ends up in the water.

Ok, but only the energy that is available?

So, no kettling, good thermal conductivity with the water, plenty of
time for the water to convect and take the heated water round the
cylinder. Heater element stays reasonably cool and therefore low
resistance therefore runs at full marked power.

Overdriven element (for the surface area), kettling, decreased contact
with the water (steam insulating the element from the water),
increased element temperature, higher resistance, reduced energy
consumption from rated, lower actual output?

Now, it may not make much of a difference ITRW but we were just
'wondering' about such things here. ;-)

Cheers, T i m

"T i m" wrote in message
...
On Sun, 25 Dec 2016 08:39:14 +1100, "Rod Speed"
wrote:

snip

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 you needed to justify what they were paying you to design stuff.

Quite ... so I guess someone must have done that for us to get a
kettle designed like that?

I think that one is more likely to have been a sensible
design improvement. Basically it allows you to heat
exactly the amount of water you plan to use, say by
filling the mug with water, then tipping that into the
just to heat it. No wasted water at all.

I do that the other way, heat the water in the microwave
in the mug I plan to drink the tea or coffee from.

On Sat, 24 Dec 2016 21:29:54 +0000, Chris Hogg wrote:

snip

So, if we put a 100kW heater in there and had it on for 1 second,
would the water end up as hot as if we put a 10kW heater in there and
had that on for 10 seconds? I'm not talking 'theoretically, I'm
talking real world here?

The (/my) 'big question' is that if (say) the heater element get's
sufficiently hot as to start to boil the surrounding water, *does* the
heat get carried into the water as effectively as if it wasn't
boiling?

If the answer is no, then you could see how if you increased the
surface are of the heater you decrease the energy / area and could
take it down to a level where there was no kettling.


Bubbles of steam on the surface of the element would certainly reduce
the amount of heat being transferred to the water, effectively acting
as insulation.

Ok.

But if you're actually putting in 100kW for 1 sec, all
that will happen is that the element itself will get hotter under
those circumstances than the 10kW/10 sec situation, and at the end of
that 1 second, it will lose that extra heat to the water and the
overall result will be the same.

Ok, fair enough.

Assuming the 100kW heater was
designed for that sort of duty*, and wasn't an over-driven 10kW one,

Of course. ;-)

I
can't see any significant benefit in running it at a lower power.

Other than when the element loses (or reduces) it's ability to
transfer it's heat to the water, the internal resistance goes up and
the power consumption goes down and so the output energy goes down?

And this would be over a sliding scale, from a single bubble to the
entire element covered.

I believe these were the sort of lines the OP was thinking re his
initial question (but not kettling specifically).

I know it's not quite the same (because it's not a closed system) but
try to accelerate a tyred vehicle past it's ability to maintain
traction and that extra power (and some of the previous power) is just
wasted.

*AIUI kettling can cause localised pitting and corrosion, but not if
the element was designed to cope.

OK.

Cheers, T i m

"Rod Speed" wrote in message
...


"T i m" wrote in message
...
On Sun, 25 Dec 2016 08:39:14 +1100, "Rod Speed"
wrote:

snip

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 you needed to justify what they were paying you to design stuff.

Quite ... so I guess someone must have done that for us to get a
kettle designed like that?

I think that one is more likely to have been a sensible
design improvement. Basically it allows you to heat
exactly the amount of water you plan to use, say by
filling the mug with water, then tipping that into the
just to heat it. No wasted water at all.

I do that the other way, heat the water in the microwave
in the mug I plan to drink the tea or coffee from.

And here I was, thinking that *I* was a tightarse.
My god wodney, you must be strapped for cash.
Here, have these brownie points.
http://images.universityherald.com/d.../9707/poop.jpg
Merry Xmas.

mechanic Wrote in message:
On Sat, 24 Dec 2016 14:22:48 +0000 (GMT+00:00), Biggles wrote:

Who has those these days?


Anyone who wants an alternative way of heating the water if the
boiler fails, or prefers to have an airing cupboard, or needs a
store of hot water to cope with parallel demands (e.g. from
several showers in use simultaneously).

Aren't the hot water cylinders supplied with integrated insulation
round them, as one package? No separate 'bulky' insulation.


Ah, I thought you meant "who has cylinders?" .........
--
Biggles


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 25/12/16 01:42, bert wrote:
The (/my) 'big question' is that if (say) the heater element get's
sufficiently hot as to start to boil the surrounding water, *does* the
heat get carried into the water as effectively as if it wasn't
boiling?

No Go watch a saucepan of water coming to the boil.

Yes, Go watch a saucepan of water coming to the boil.

With a lid on it.

On 25/12/16 02:45, T i m wrote:
On Sun, 25 Dec 2016 08:39:14 +1100, "Rod Speed"
wrote:

snip

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 you needed to justify what they were paying you to design stuff.

Quite ... so I guess someone must have done that for us to get a
kettle designed like that?

Cheers, T i m

the incredible naivete that assumes that someone actually designs
electric kettles with some sort of ideal of excellence in mind
astonishes me.

They are designed to look sexy, and sell. One or two of the minor
attributes is that they also need to boil water and not kill customers.

More time will be spent designing the box they are sold in.

On 25/12/16 02:52, T i m wrote:


Now, it may not make much of a difference ITRW but we were just
'wondering' about such things here. ;-)


No, we are not wondering. You are wondering, because you are naive and
ignorant.

Everyone else knows that is all ********. Its almost impossible to make
an inefficient kettle in terms of electricity in versus heat transferred
to the water.

And the amount of electricity used is not enough to seriously warrant
any time being spent on making it marginally better.

I suggest you direct your limited intellect to more useful issues, like
whether green cars are faster than white ones.

"T i m" wrote in message
...
On Sun, 25 Dec 2016 09:31:05 +1100, "John" wrote:

snip

So, are you saying that a 'kettling' element *will* be transferring
it's energy to the water as effectively as one with say twice the
surface area that wasn't kettling?

Yes, because there is nowhere else for the heat to go.

(straight question).

Just as well, I don't like bent questions.

;-)

So we aren't talking directly about a loss of energy here, but
a loss of efficiency (because of kettling and other variables).

That isnt loss of efficiency, all the heat still ends up in the water.

Ok, but only the energy that is available?

So, no kettling, good thermal conductivity with the water, plenty of
time for the water to convect and take the heated water round the
cylinder. Heater element stays reasonably cool and therefore low
resistance therefore runs at full marked power.

Overdriven element (for the surface area), kettling, decreased contact
with the water (steam insulating the element from the water),
increased element temperature, higher resistance, reduced energy
consumption from rated, lower actual output?

The difference in resistance due to the higher element temperature
would be very small and so amount of heat available would only
change very minimally.

Now, it may not make much of a difference ITRW but we were just
'wondering' about such things here. ;-)

Yeah, it would certainly see a small change in the heat available.

In article ,
mechanic wrote:
On Sat, 24 Dec 2016 14:22:48 +0000 (GMT+00:00), Biggles wrote:

Who has those these days?


Anyone who wants an alternative way of heating the water if the
boiler fails, or prefers to have an airing cupboard, or needs a
store of hot water to cope with parallel demands (e.g. from
several showers in use simultaneously).

Aren't the hot water cylinders supplied with integrated insulation
round them, as one package? No separate 'bulky' insulation.

They are now. The "bulky insulation" was for adding to cylinders that had
none.

--
from KT24 in Surrey, England

On Sat, 24 Dec 2016 11:13:15 +0000, newshound wrote:

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


pedant
If you put fins on the cladding the heat transfer would improve, and the
resistive element would run a bit cooler. That might improve its life?
Also, a cooler element would have lower resistance, hence slightly
higher current and output.
/pedant

AFAIK the resistance is very little affected by temperature - just as well,
reaaly, as a 3kW element that has low resistance at cold...!

For kettles, the "concealed" (I think of it as remote) element will run
hotter than the immersed type. The area of the element is very low and there
might be an advantage to having a physically larger one to transfer the same
rate of heat at a lower temperature. The plate at the bottom of the kettle
gets very hot I'd guess, judging by the colour. It might also spread the
scale to a thinner layer(?).
--
Peter.
The gods will stay away
whilst religions hold sway