I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?

Peter wrote:
I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?

I think Myson have traditionally dominated this sector, but their units
were neither compact nor pretty last I saw - but that was a fair while
ago.

You can diy your own with a normal rad + several pc fans on reduced V

Presumably you could also put rad + fan under the floor if you wanted,
with filtered vents.

But the best option (that Ive never tried) appears to be to put a bunch
of microbore inside partition walls. Raising the whole wall to quite
modest temps would deliver the same heat. I calculated it once, and it
looked like it would work well.

Anyone else considered this?


NT

In article .com,
says...
Peter wrote:
I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

I have one in my car :-)

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?

Most of the heat transfer is by convection. Large white radiators don't
look as crap as slightly smaller black ones, and are easier to paint to
match the room decor.

I think Myson have traditionally dominated this sector, but their units
were neither compact nor pretty last I saw - but that was a fair while
ago.

You can diy your own with a normal rad + several pc fans on reduced V

Presumably you could also put rad + fan under the floor if you wanted,
with filtered vents.

But the best option (that Ive never tried) appears to be to put a bunch
of microbore inside partition walls. Raising the whole wall to quite
modest temps would deliver the same heat. I calculated it once, and it
looked like it would work well.

Anyone else considered this?

Wouldn't it make more sense to put it under the floor?

In an earlier contribution to this discussion,
Peter wrote:

I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

Maybe not quite what you want, but Myson do 'Kickspace' fan-blown radiators
which fit under kitchen units in otherwise dead space.

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?

The word 'radiator' is a misnomer in this context. Most of the heat transfer
is by convection with only a small amount being radiated. Making them matt
black would increase the radiated heat a bit - but wouldn't have a dramatic
effect on overall heat output - and would be considered less aesthetically
acceptable by most!
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

Set Square wrote:

Maybe not quite what you want, but Myson do 'Kickspace' fan-blown radiators
which fit under kitchen units in otherwise dead space.


but all the ones I've seen are noisy and not very effective - they have
the fan heater problem of warming the room up quickly but then allowing
it to cool down just as fast - there's no thermal mass.

--
Spamtrap in use
To email replace 127.0.0.1 with blueyonder dot co dot uk

but all the ones I've seen are noisy and not very effective - they have
the fan heater problem of warming the room up quickly but then allowing
it to cool down just as fast - there's no thermal mass.

Hmm, yes. This is what concerns me, I definitely do not want the noise
a fan heater, nor the draught, but I can't help feeling that a 2 metre
long tangential fan rotating at a pretty slow speed could be quite
inaudible, yet seriously increase the airflow throw a radiator.

On Wed, 05 Oct 2005 19:19:32 +0100, Peter
wrote:

but all the ones I've seen are noisy and not very effective - they have
the fan heater problem of warming the room up quickly but then allowing
it to cool down just as fast - there's no thermal mass.

Hmm, yes. This is what concerns me, I definitely do not want the noise
a fan heater, nor the draught, but I can't help feeling that a 2 metre
long tangential fan rotating at a pretty slow speed could be quite
inaudible, yet seriously increase the airflow throw a radiator.

The myson ones work but become noisy.
A slow or variable speed tangential fan as you suggest would be alot
better if available.

You could fit a few 60mm fans between the 2 parts of a small double
convector rad , easy to control and run them from a plugin low volatge
adaptor.

Robert
royall at which net

"Peter" wrote in message
...
I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?

==================
You might possibly be a suitable candidate for skirting radiators.

They don't suit everybody or every location but they're worth a look if
you're determined to avoid standard panel radiators. You might be able to
combine skirting rads and tangential fans to achieve a bespoke system, but I
doubt if it will be cheap.

Try a 'google' for 'skirting radiators'.

Cic.

On Wed, 05 Oct 2005 14:37:04 +0100, Set Square wrote:

The word 'radiator' is a misnomer in this context. Most of the heat transfer
is by convection with only a small amount being radiated. Making them matt
black would increase the radiated heat a bit - but wouldn't have a dramatic
effect on overall heat output - and would be considered less aesthetically
acceptable by most!

AIUI the heat transfer is about 30% by radiation but much less when they
are being run cooler using TRVs and/or condensing boilers.
The emissivity of the white enamel is not far of the perfect matt black
(about 90% as good). In fact most surfaces have emissivities around this
figure the only ones which don't are shiny metal ones. If you play about
with an IR thermometer you'll soon see which ones have low emissivities.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

In article ,
Cicero wrote:

"Peter" wrote in message
...
I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?

==================
You might possibly be a suitable candidate for skirting radiators.

They don't suit everybody or every location but they're worth a look if
you're determined to avoid standard panel radiators. You might be able to
combine skirting rads and tangential fans to achieve a bespoke system, but I
doubt if it will be cheap.

Try a 'google' for 'skirting radiators'.

Or look at vertical radiators that only take up a small length of wall and can
be sufficiently decorative to take the place of a piece of modern art that you
might have there instead.

--
John Cartmell john@ followed by finnybank.com 0845 006 8822
Qercus magazine FAX +44 (0)8700-519-527 www.finnybank.com
Qercus - the best guide to RISC OS computing

wrote:

But the best option (that Ive never tried) appears to be to put a bunch
of microbore inside partition walls. Raising the whole wall to quite
modest temps would deliver the same heat. I calculated it once, and it
looked like it would work well.

Anyone else considered this?

Yes, it is done regularly with radiant floor plates fixed in the studs
& covered with plasterboard.

Peter wrote:

Hmm, yes. This is what concerns me, I definitely do not want the noise
a fan heater, nor the draught, but I can't help feeling that a 2 metre
long tangential fan rotating at a pretty slow speed could be quite
inaudible, yet seriously increase the airflow throw a radiator.

It won't work. CH radiators work by radiation and convection. Fan
heaters work by convection and the surface area needs to be vastly
increased to achieve the required heat transfer. An example would be a
car radiator which dissipates heat by forced convection. The surface
area is made vast by the use of lots of sheet metal fins to transfer
the heat to the airstream. If you want a fan heater you'd have to use
one of the Myson jobs or obtain an air heater battery and go about
fabricating a small air handler.

There are commercial fan coil units for heating and/or cooling, similar
to the indoor ceiling cassettes on split system AC units. The cheap and
nasty fans usually start giving trouble after a few years.

Aidan wrote:
Peter wrote:

Hmm, yes. This is what concerns me, I definitely do not want the noise
a fan heater, nor the draught, but I can't help feeling that a 2 metre
long tangential fan rotating at a pretty slow speed could be quite
inaudible, yet seriously increase the airflow throw a radiator.

It won't work. CH radiators work by radiation and convection. Fan
heaters work by convection and the surface area needs to be vastly
increased to achieve the required heat transfer.

It works very well in fact. I know because I've done it as a temporary
measure. Its the same principle as fan cooling a heatsink in tronic
goods. Think your CPU wont get hotter if the fan fails?

The only problem is getting or making a long thin fan. I guess in
principle one could make a tangential thing and spin it at low rpm,
sounds a fair bit of work tho. Practically pc fans are all I've come up
with, anything else is too large.

Now how to diy a 5' tangential fan...


NT

wrote:

It works very well in fact. I know because I've done it as a temporary
measure.

It increases the proportion of heat emitted by convection. It reduces
the
radiator surface temperature and reduces the proportion of heat emitted
by radiation. The overall effect approximates to naff all, in respect
for the effort involved. If he wants forced convection, he'd be best
advised to buy a heater battery which is designed for this purpose. Or
some of those finned tube heaters.

This is why car radiators and heater matrices are the distinctive shape
that they are. You could bolt on a couple of double-panel Mysons when
your car radiator next fails, but I doubt that it would achieve the
required heat transfer rate.

Its the same principle as fan cooling a heatsink in tronic
goods. Think your CPU wont get hotter if the fan fails?

The heatsink usually has extended fins to shift a few watts; I have no
idea of typical CPU heat output. To shift a 1 or 2 kW, you need lots of
fins, or a large acreage of panel radiators.

It increases the proportion of heat emitted by convection. It reduces
the radiator surface temperature and reduces the proportion of heat emitted
by radiation.

Well, yes, but it should take heat from the radiator by design, I am
actually trying to tale the most from the radiator. Either way, if the
control system and the boiler is correctly specified it should keep
the radiator piping hot at the maximum level of air flow forced
through the radiator; again, by design.

Ed Sirret, said above that very little energy is emitted from a
'radiator' by way of radiation anyway.

The overall effect approximates to naff all, in respect
for the effort involved. If he wants forced convection, he'd be best
advised to buy a heater battery which is designed for this purpose. Or
some of those finned tube heaters.

I'm not familiar with 'finned tube' though I think I know those you
mean. But it's space I am trying to save. I would love to have a very
flat skirting board radiator of 2m length, which is capable of
maintaining an already warm room, but which has a fan mode to boost
its capacity when the room is being heated from cold.

This is why car radiators and heater matrices are the distinctive shape
that they are. You could bolt on a couple of double-panel Mysons when
your car radiator next fails, but I doubt that it would achieve the
required heat transfer rate.

Yes, but car radiators are cooling pretty inefficient 90kW (or
thereabouts) motors. Their design owes a lot to the much greater
cooling they must provide, much like the complexity we see in the
heatsinks used in power electronics.

If they weren't so ugly it might be fun to try an automotive radiator
in a CH system. Though perhaps its fan motor could be replaced with
something a little less energetic.

Anyway, in the meantime I think I would like to track down a
manufacturer of tangential fans and call them to ask what the longest
design they make is. It should be quite a simple experiment.

In an earlier contribution to this discussion,
Aidan wrote:

wrote:

It works very well in fact. I know because I've done it as a
temporary measure.

It increases the proportion of heat emitted by convection. It reduces
the
radiator surface temperature and reduces the proportion of heat
emitted by radiation.

Not necessarily! Provided the water flow rate is increased to replenish the
heat at the same rate as it is being removed, the surface of the rad will
stay at the same temperature as before - thus giving increased convection
and the same radiation.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

On Wed, 05 Oct 2005 00:09:18 +0100, Peter
wrote:

I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?

How much time/money do you want to spend?

cheers,
Pete.

How much time/money do you want to spend?

Hard to say but under a thousand for sure.

Peter wrote:
How much time/money do you want to spend?

Hard to say but under a thousand for sure.

achievable with rows of computer fans on standard but smaller rads.

NT

Aidan wrote:
wrote:

It works very well in fact. I know because I've done it as a temporary
measure.

It increases the proportion of heat emitted by convection. It reduces
the
radiator surface temperature and reduces the proportion of heat emitted
by radiation. The overall effect approximates to naff all, in respect
for the effort involved. If he wants forced convection, he'd be best
advised to buy a heater battery which is designed for this purpose. Or
some of those finned tube heaters.

This is why car radiators and heater matrices are the distinctive shape
that they are. You could bolt on a couple of double-panel Mysons when
your car radiator next fails, but I doubt that it would achieve the
required heat transfer rate.

Its the same principle as fan cooling a heatsink in tronic
goods. Think your CPU wont get hotter if the fan fails?

The heatsink usually has extended fins to shift a few watts; I have no
idea of typical CPU heat output. To shift a 1 or 2 kW, you need lots of
fins, or a large acreage of panel radiators.


I know what Im talking about.

NT

Peter wrote:

Well, yes, but it should take heat from the radiator by design, I am
actually trying to tale the most from the radiator. Either way, if the
control system and the boiler is correctly specified it should keep
the radiator piping hot at the maximum level of air flow forced
through the radiator; again, by design.

It won't.

Ed Sirret, said above that very little energy is emitted from a
'radiator' by way of radiation anyway.

If they weren't so ugly it might be fun to try an automotive radiator
in a CH system. Though perhaps its fan motor could be replaced with
something a little less energetic.

You could get the fan and heater matrix from a car. The heater matrix
is copper pipes expanded into ali fins. The fins are so closely packed
on some that, at first glance, they look like a block of grooved
aluminium. At a flying guess, I'd think you'd get 1 kW from a heater
battery 200mm square, depending on the fin density, but much smaller
than a rad, with or without fans.

Anyway, in the meantime I think I would like to track down a
manufacturer of tangential fans and call them to ask what the longest
design they make is. It should be quite a simple experiment.

Centrifugal fans. The options are axial flow (Vent-Axias), centrifugal
or mixed flow. The impellers in fan convectors are centrifugal but are
forward curved. Real, efficient, commercial fans have backward curved
blades (or is that the other way round?), but look very different to
the injection moulded forward curved jobs. Try Ziehl if you want to
make something fancy with speed controls. Quality, but much =A3s.

Rads are frequently run off variable temperature systems, modulating
boilers or weather compensated. Convectors should be run from a
constant temperature system; it will still put out some heat but a
variable temperature system would play havoc with any accurate control
systems.

wrote:
Aidan wrote:

I know what Im talking about.

Once upon a time, there was an article in a car magazine about a car
being developed by some racing car constructors. They had had the
bright idea of dispensing with the conventional radiator (similar to a
heater battery). They were making the car with a double-skinned body;
by circulating the coolant through the space, they would cool the car
(similar to a CH radiator) and get rid of the drag caused by all those
finny things.

A certain fluids lecturer spotted this. Dr. M (for it was he) wrote to
the editor saying that, whilst this was a splended idea, he calculated
the car would need a surface area similar to that of a bus (double
decker) to dissipate the heat. The letter was printed. The racing car
constructors replied. They said their idea would work, that these
academics should stick to their labs and leave the construction of
racing cars to those who knew the business, ie.., them. The letter was
printed.

Come the great unveiling and the car was rolled out to much press
interest. It sped off around the circuit. Then it stopped in a cloud of
steam. It was wheeled back into the workshop for minor adjustments to
resolve this teething problem. It hasn't been seen since.

In article . com,
says...
Peter wrote:
How much time/money do you want to spend?

Hard to say but under a thousand for sure.

achievable with rows of computer fans on standard but smaller rads.

But is it art?

Anna

--
~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repairs
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642

"Aidan" wrote:

snip

It hasn't been seen since.

So it was really fast then?

:-)


--

Thanks Aidan, That's good advice for my looming project.

Matt wrote:
"Aidan" wrote:


So it was really fast then?

:-)

Good for sprints
:-))

On Thu, 6 Oct 2005 12:34:14 +0100, "Set Square"
wrote:

In an earlier contribution to this discussion,
Aidan wrote:

wrote:

It works very well in fact. I know because I've done it as a
temporary measure.

It increases the proportion of heat emitted by convection. It reduces
the
radiator surface temperature and reduces the proportion of heat
emitted by radiation.

Not necessarily! Provided the water flow rate is increased to replenish the
heat at the same rate as it is being removed, the surface of the rad will
stay at the same temperature as before - thus giving increased convection
and the same radiation.

I agree, with forced convection the rate of cooling is faster than
with natural convection (for the same temperature difference)
So as long as you increase the flowrate thro' rad you will get more
heat output.
The heat output to size ratio can be optimised by design as in car
rads or fan convectors, just as the design of a normal convector rad
attempts to maximse the heat output by natural convection in a design
acceptable for domestic use.

Robert
royall at which net

In an earlier contribution to this discussion,
Anna Kettle wrote:


achievable with rows of computer fans on standard but smaller rads.

But is it art?

Anna

Does it have to be? g
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

age wrote:

I agree, with forced convection the rate of cooling is faster than
with natural convection (for the same temperature difference)
So as long as you increase the flowrate thro' rad you will get more
heat output.

Do you not think that the rate of heat transfer from the fluid to the
inside surface of the radiator might be dependent on & limited by the
surface area?

On Thu, 6 Oct 2005 16:15:54 +0100, Anna Kettle
wrote:

In article . com,
says...
Peter wrote:
How much time/money do you want to spend?

Hard to say but under a thousand for sure.

achievable with rows of computer fans on standard but smaller rads.

But is it art?

Some fans with LEDs could look nice, more k3wl than arty maybe...

Anyway, the OP should have better luck looking for a cross flow fan
(AKA tangential fan):

http://www.casetech.co.uk/CoolerMaster-300mm-Cross-Flow-Fan-p-17326.html
http://www.review-displays.co.uk/Products/motors/orix.htm
http://www.ebmpapst.co.uk/pages/content.asp?s_16,p_2
http://www.google.com/search?hl=en&lr=&safe=off&client=opera&rls=en&q=si te%3A.co.uk+cross+flow+fan&btnG=Search

...etc

One of the coolermaster ones with a car heater matrix would form a
nice 'mini Myson'.

I'd try a row of 80mm PC case fans first, they are pretty quiet on 5v
and 3-7v 2A wall wart could run a whole load of them. eBuyer have a
pretty good range.

cheers,
Pete.

Aidan wrote:
wrote:
Aidan wrote:

I know what Im talking about.

Once upon a time, there was an article in a car magazine about a car
being developed by some racing car constructors. They had had the
bright idea of dispensing with the conventional radiator (similar to a
heater battery). They were making the car with a double-skinned body;
by circulating the coolant through the space, they would cool the car
(similar to a CH radiator) and get rid of the drag caused by all those
finny things.

A certain fluids lecturer spotted this. Dr. M (for it was he) wrote to
the editor saying that, whilst this was a splended idea, he calculated
the car would need a surface area similar to that of a bus (double
decker) to dissipate the heat. The letter was printed. The racing car
constructors replied. They said their idea would work, that these
academics should stick to their labs and leave the construction of
racing cars to those who knew the business, ie.., them. The letter was
printed.

Come the great unveiling and the car was rolled out to much press
interest. It sped off around the circuit. Then it stopped in a cloud of
steam. It was wheeled back into the workshop for minor adjustments to
resolve this teething problem. It hasn't been seen since.

And?

If you think that supports your case...

Its not worth getting into, you dont understand basic thermodynamics.


NT

Anna Kettle wrote:
In article . com,
says...
Peter wrote:
How much time/money do you want to spend?

Hard to say but under a thousand for sure.

achievable with rows of computer fans on standard but smaller rads.

But is it art?

Anna

To some people, anything is art! The idea is to put the fans out of
sight at the bottom behind the rad. They need to be run on reduced
voltage to keep them quiet. Unfanned airlfow is so slow that even
modest air movement can triple output.


NT

wrote:

And?

And it is an anecdote which was used to illustrate that CH radiators
that work by natural convection & radiation are not the same as
radiators that are designed to use forced convection to dissipate heat.
Horses for courses.

If you think that supports your case...

What case? I have no case. If you feel an urge to stick fans on CH
radiators, go right ahead. Personally, I wouldn't bother. There are
better ways of making fan convectors. What any fool can do for a
quid.......

Its not worth getting into, you dont understand basic thermodynamics.

Ooooh, Hissssssy, Hissy!

Strangely, the one book that was on my desk when I read that comment
was 'Applied Thermodynamics for Engineering Technologists' by Eastop &
McConkey. It is, in fact, my second copy which I bought from E-Bay, the
first was bought in 1976 and disintegrated from excessive use a couple
of years ago. Nor was it out for use in this discussion; my son's Tech
homework was about the R101 & I had refreshed my acquaintance with the
perfect gas laws in order to work out the lift of the R100, from the
figures for the weight & volume given in Nevil Shute's autobiography
'Slide Rule'.

If I gave a crap, I might have taken umbrage there.

I don't think that's right. The fin design on all radiators I've seen
is pretty basic - no more than a thin sheet of steel made into a wavy
shape and spot welded to the panel. The transfer of heat from the
panel to the fins is limited by the design and I think that you'd find
that with a powerful fan you could get the fin temperature down quite
low but the panel temperature would remain high simply because of the
poor thermal transfer characteristic. Next time your heating is on try
feeling the temperature on the panel, on the fins near the panel and on
the end of the fins furthest from the panel.
I've often toyed with the idea of boosting certain rads in this way and
I suspect it would work to some degree if I could be bothered.

Wet fan heaters such as Mysons plinth heaters use a longitudinal fan
and one of the features of all such fans is that over time they "sag".
Once that happens they become unbalanced and start to get noisy. I
know, I've got one :-(
For that reason I wouldn't bother with a longitudinal fan below a panel
radiator. If I was playing with such a design I'd go for small
electronics fans running very slowly.

On 6 Oct 2005 13:03:47 -0700, "Aidan" wrote:


wrote:

I agree, with forced convection the rate of cooling is faster than
with natural convection (for the same temperature difference)
So as long as you increase the flowrate thro' rad you will get more
heat output.

Do you not think that the rate of heat transfer from the fluid to the
inside surface of the radiator might be dependent on & limited by the
surface area?
I would agree that there are many factors which affect the
total heat output and without detailed modelling or actual
measurements determining exactly how much each factor affects the
output is difficult.
However I have noticed that in myson fan convectors and skirting board
convectors the fins are attached to a simple pipe, whose internal
surface area is much smaller than that of a normal rad. Therefore I
would assume that transfer of heat from the water to the rad is not
normally a problem.

My advise would be to attach a few computer fans to a double convector
rad, let the rad get to a stable temperature - measure the inlet to
outlet temp diff , switch fans on and see if the temp diff increases
significantly.

Robert
royall at which net

age wrote:

My advise would be to attach a few computer fans to a double convector
rad, let the rad get to a stable temperature - measure the inlet to
outlet temp diff , switch fans on and see if the temp diff increases
significantly.

What's stopping you? Let us know how it turns out.

Calvin wrote:
I don't think that's right. The fin design on all radiators I've seen
is pretty basic - no more than a thin sheet of steel made into a wavy
shape and spot welded to the panel.

There is one corrugated fin, spot welded on at about 15mm intervals.
Let us say there's two fins per inch.

On proper heater batteries, the copper pipes are passed through ali or
copper sheet fins which have holes punched in them. 12 or 18 fins per
inch is not unusual. The pipes are hydraulically expanded to ensure a
wide contact area between the pipe and the fin metal.

Now, why do you think they'd do all that? Do you think it might be
possible that the amount of heat transferred is somehow related to the
surface area of the heated metal?

Next time your heating is on try
feeling the temperature on the panel, on the fins near the panel and on
the end of the fins furthest from the panel.

Granny. Eggs. Suck

Aidan wrote:
wrote:

Its not worth getting into, you dont understand basic thermodynamics.

Ooooh, Hissssssy, Hissy!

no, just getting real.


Strangely, the one book that was on my desk when I read that comment
was 'Applied Thermodynamics for Engineering Technologists'

sounds like you ought to know better then

NT

Peter wrote:

I have room for wall mounted radiators but I really don't want to give
away wall space to some big white thing.

Are there any small radiator designs that contain discreet tangential
fans to enhance their output?

And a quite separate question. Why are radiators white, or even
chrome? Surely matt black would make them more efficient, so they
could be smaller?
Yes. fan blown 'wet' heaters. Mine have 'smiths' on them About 1.5KW output.
About 500mm square, fit in 4" depth.

wrote:

sounds like you ought to know better then

Yes, I should.

If one did know better, how would those who know no better know that
you knew better than they?