What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.

On 06/05/2021 13:10, Fredxx wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.




Try telling that to the female who has decided that "we need" vertical
designer rads.

On Thu, 06 May 2021 13:10:17 +0100, Fredxx wrote:

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.


So where does the heat loss go other than in the room..?

jon wrote:
So where does the heat loss go other than in the room..?

Hotter water returning to the boiler. Less gas gets burnt, but the room is
colder.

(plus a bit into the wall, depending on its insulation)

Theo

On Thursday, 6 May 2021 at 13:10:20 UTC+1, Fredxx wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.
For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.

Likely true. But, in many cases, so what?

Let's assume a horizontal radiator is 100% efficient.

But how much of the time does that efficiency matter? I suspect a large proportion of radiators are throttled by a TRV. Further, if the radiator can cope on the coldest days, it probably has plenty of capacity in hand for most of the rest of the year.

Dropping efficiency to, I suggest, 90% would only really affect that small period during which the absolute maximum output is required.

On Thu, 6 May 2021 11:55:00 -0000 (UTC), jon wrote:


What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

Because efficiency is a measure of 'how well' not 'how' a system
works.

With a tall / narrow rad, most of the air rising up / around the rad
will already have been warmed by the lower sections and so only the
lower sections will be working 'efficiently' (hot rad cold air V hot
rad already warm air (= lower temperature gradient)).

With a wide / low rad, much more of the height / length of the rad
will be transferring the heat from the rad air room and so it will
(for the same area) be able to transfer the heat to the room
efficiently / faster.

It is this way because the air is moving over the rad by natural
convection and that means vertically. Make the rads 'fan assisted'
and, (depending on the design) make far less difference re the
orientation.

Cheers, T i m

On Thu, 6 May 2021 13:35:57 +0100, Andrew
wrote:

snip

Try telling that to the female who has decided that "we need" vertical
designer rads.

Fancy allowing anyone without the understanding of the physics to
determine such things (irrespective of their gender).

Cheers, T i m

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

It is true (though 'effective' would be a better word) because of the
reasons given by T i m and others. Look at the manufacturer's figures
for power output and you'll see.

As a result, a vertical rad will be heavier and (usually much) more
expensive. The upsides are that they take up less width, and when you
come in from the cold you can stand against one.

--
Cheers
Clive

On 06/05/2021 13:46, jon wrote:
On Thu, 06 May 2021 13:10:17 +0100, Fredxx wrote:

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

The physical geometry of the "radiator" affects how well it transfers
heat to its environment. Convection is the most important by far.

Shiny metallic "radiators" like chrome towel rails in the bathroom
hardly radiate any heat at all and once you put a towel onto them they
don't do very much to warm up the air in the bathroom either.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.

So where does the heat loss go other than in the room..?

Hotter water leaves the radiator exit port than would be the case for a
radiator with a more appropriate geometry.

The critical thing is how much area is at each temperature and the
airflow over it. The amount of heat that the "radiator" which actually
loses most of its heat to the room by convection can transfer to the
air. There is an optimum height, width and wall separation for maximum
heat transfer. Insulating the wall behind a radiator improves it a bit
if the wall is an outside one. You can see any radiators mounted on
outside walls with thermal imaging. It matters less on an interior wall.

If you choose three radiators of 1m^2 with very different geometries.

Height x Width
0.5 x 2
1 x 1
2 x 0.5

The first will work best of all since it has a stripe of 2m length that
is at inlet temperature and releases warm air low down in the room.

The second is a bit more practical and would still work well enough.
Most are typically around a 1:2 ratio of height to length.

The last one has a much smaller stripe at the highest temperature and
mostly delivers hot air to the ceiling (where it stays). They are a
designer fad that serves no useful purpose (except to sell more
replacement radiators when they prove to be unsatisfactory).

If you happen to live on the ceiling then they might be useful to you.

--
Regards,
Martin Brown

On 06/05/2021 14:13, Clive Arthur wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

It is true (though 'effective' would be a better word) because of the
reasons given by T i m and others.Â* Look at the manufacturer's figures
for power output and you'll see.

As a result, a vertical rad will be heavier and (usually much) more
expensive.Â* The upsides are that they take up less width, and when you
come in from the cold you can stand against one.

More accurately you will have to stand against one to get warm!


--
Regards,
Martin Brown

On Thu, 6 May 2021 05:50:51 -0700 (PDT), polygonum_on_google
wrote:

snip

But how much of the time does that efficiency matter? I suspect a large proportion of radiators are throttled by a TRV.

Yes, *once* the room is up to temperature?

Further, if the radiator can cope on the coldest days, it probably has plenty of capacity in hand for most of the rest of the year.

Agreed, once it has brought the room up to temperature. ;-)

Dropping efficiency to, I suggest, 90% would only really affect that small period during which the absolute maximum output is required.

And how long it takes to get the room up to temperature. ;-)

My first experience of the reliance on 'central heating' was as a kid
and when going back to my mates house after playing in the snow.

At our house we had pretty crude coal fired free standing boiler,
gravity fed rad system and so also had electric fan heaters to 'top
up' as / when / where required.

If you came in cold you could flick one on and sit right in front of
it and be warmed up pretty quickly.

So, mate turns the central heating on and we have to stand next to the
radiators waiting for some heat to get in them to be able to thaw our
fingers out again. ;-(

Cheers, T i m

On 06/05/2021 14:13, Clive Arthur wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

It is true (though 'effective' would be a better word) because of the
reasons given by T i m and others.Â* Look at the manufacturer's figures
for power output and you'll see.

As a result, a vertical rad will be heavier and (usually much) more
expensive.Â* The upsides are that they take up less width, and when you
come in from the cold you can stand against one.


But cannot sit on them :-(

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.


As I think I said the last time this came up, my physics is nowhere near
good enough to decide "by inspection" whether a vertical or horizontal
radiator is better at transferring heat to a room. And (like some
others) I saw too many /known/ unknowns - e.g laminar flow? temperature
of air exiting top? chimney effect? - quite apart from the possible
unknown^2

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ


--
Robin
reply-to address is (intended to be) valid

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

Very easily. How 'efficient' is a radiator in a polystyrene box?

What the OP means is not heat in to heat out, but peak heat flow.

a vertical radiator will be transferring heat from its top to already
hot air, so less 'efficient' in terms of peak heatflow into the room, in
the same way that I have 2KW heaters the size of a cornflake packet
because they are fan blown

With 'radiators' airflow is everything. There is not much 'radiation'
going on at 60C...


--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

On 06/05/2021 13:46, jon wrote:
On Thu, 06 May 2021 13:10:17 +0100, Fredxx wrote:

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.


So where does the heat loss go other than in the room..?

The heat loss is imply LESS overall


--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

On 06/05/2021 13:50, polygonum_on_google wrote:
On Thursday, 6 May 2021 at 13:10:20 UTC+1, Fredxx wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.
For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.

Likely true. But, in many cases, so what?

Let's assume a horizontal radiator is 100% efficient.

wrong understanding of 'efficient'

how about a rewrite of the OP

'vertical radiators are less *effective* at heating a room than
horizontal ones'




But how much of the time does that efficiency matter? I suspect a large proportion of radiators are throttled by a TRV. Further, if the radiator can cope on the coldest days, it probably has plenty of capacity in hand for most of the rest of the year.

Dropping efficiency to, I suggest, 90% would only really affect that small period during which the absolute maximum output is required.



--
Labour - a bunch of rich people convincing poor people to vote for rich
people by telling poor people that "other" rich people are the reason
they are poor.

Peter Thompson

On 06/05/2021 14:13, Clive Arthur wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

It is true (though 'effective' would be a better word) because of the
reasons given by T i m and others.Â* Look at the manufacturer's figures
for power output and you'll see.

As a result, a vertical rad will be heavier and (usually much) more
expensive.Â* The upsides are that they take up less width, and when you
come in from the cold you can stand against one.

and UFH is better than either!

--
Labour - a bunch of rich people convincing poor people to vote for rich
people by telling poor people that "other" rich people are the reason
they are poor.

Peter Thompson

In article , The Natural Philosopher
wrote:
On 06/05/2021 13:50, polygonum_on_google wrote:
On Thursday, 6 May 2021 at 13:10:20 UTC+1, Fredxx wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.
For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.

Likely true. But, in many cases, so what?

Let's assume a horizontal radiator is 100% efficient.

wrong understanding of 'efficient'

how about a rewrite of the OP

'vertical radiators are less *effective* at heating a room than
horizontal ones'

So, you choose a slightly larger one




But how much of the time does that efficiency matter? I suspect a large
proportion of radiators are throttled by a TRV. Further, if the
radiator can cope on the coldest days, it probably has plenty of
capacity in hand for most of the rest of the year.

Dropping efficiency to, I suggest, 90% would only really affect that
small period during which the absolute maximum output is required.


--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

In article ,
jon wrote:
On Thu, 06 May 2021 13:10:17 +0100, Fredxx wrote:

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.


So where does the heat loss go other than in the room..?

People do tend to use efficiency meaning how well it works, rather than
the scientific meaning. And it could well be a horizontal rad of the same
size as a vertical one gets heat into the room better.

--
*If PROGRESS is for advancement, what does that make CONGRESS mean?

Dave Plowman London SW
To e-mail, change noise into sound.

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.


Efficacy?

--
Adrian C

On 06/05/2021 14:47, Tim Streater wrote:
On 06 May 2021 at 13:35:57 BST, Andrew
wrote:

On 06/05/2021 13:10, Fredxx wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.

Try telling that to the female who has decided that "we need" vertical
designer rads.

Bugger the designer aspect. It all depends on available wall space. A tall rad
of a given width should put out more heat than a shorter one.

Yes, but not in proportion to it's height.

"jon" wrote in message ...
On Thu, 06 May 2021 13:10:17 +0100, Fredxx wrote:

On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.


So where does the heat loss go other than in the room..?

Less heat is extracted from the circulating water.

"Clive Arthur" wrote in message
...
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

It is true (though 'effective' would be a better word) because of the
reasons given by T i m and others. Look at the manufacturer's figures for
power output and you'll see.

As a result, a vertical rad will be heavier and (usually much) more
expensive. The upsides are that they take up less width, and when you
come in from the cold you can stand against one.

I preferred to sit on the horizontal one in that situation.

"Robin" wrote in message
...
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

As I think I said the last time this came up, my physics is nowhere near
good enough to decide "by inspection" whether a vertical or horizontal
radiator is better at transferring heat to a room.

Yes, you clearly have that problem. Plenty of us dont.

And (like some others)

Who have the same problem.

I saw too many /known/ unknowns - e.g laminar flow? temperature of air
exiting top? chimney effect? - quite apart from the possible unknown^2

None of that matters. What matters is the vertical distance.

There is no chimney effect with a radiator.

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ

"The Natural Philosopher" wrote in message
...
On 06/05/2021 14:13, Clive Arthur wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

It is true (though 'effective' would be a better word) because of the
reasons given by T i m and others. Look at the manufacturer's figures
for power output and you'll see.

As a result, a vertical rad will be heavier and (usually much) more
expensive. The upsides are that they take up less width, and when you
come in from the cold you can stand against one.

and UFH is better than either!

Thats very arguable indeed. The big problem with under floor
heating is the floor covering. One hotel room I stayed in on a
not all that cold day was so cool that the only way I could be
warm enough was to lie on the carpeted floor. **** that.

And the other problem is hot feet with the body not warm enough.

On 06/05/2021 17:40, Rod Speed wrote:


"Robin" wrote in message
...
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

As I think I said the last time this came up, my physics is nowhere
near good enough to decide "by inspection" whether a vertical or
horizontal radiator is better at transferring heat to a room.

Yes, you clearly have that problem. Plenty of us dont.

I don't know why you say that, as the chimney effect can sometimes be
very good at providing a good airflow. So at first sight it's not
obvious which orientation is best. Only those with hindsight will think
differently.

And (like some others)

Who have the same problem.

I saw too many /known/ unknowns - e.g laminar flow? temperature of air
exiting top? chimney effect? - quite apart from the possible unknown^2

None of that matters. What matters is the vertical distance.

There is no chimney effect with a radiator.

The gap between the radiator and the wall and radiator height will
determine air speed over the radiator.

If you think differently, please feel free to cite an explanation why
this isn't the case.

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ

On Fri, 7 May 2021 02:25:24 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the trolling senile asshole's latest troll**** unread

02:25, yet AGAIN, you subnormal senile troll? Authentic sociopaths like you
just NEVER have ANY feelings of shame, right?

--
Marland answering senile Rodent's statement, "I don't leak":
"That¢s because so much **** and ****e emanates from your gob that there is
nothing left to exit normally, your arsehole has clammed shut through disuse
and the end of prick is only clear because you are such a ******."
Message-ID:

"charles" wrote in message
...
In article , The Natural Philosopher
wrote:
On 06/05/2021 13:50, polygonum_on_google wrote:
On Thursday, 6 May 2021 at 13:10:20 UTC+1, Fredxx wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.
For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.

It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.

So hardly nonsense.

Likely true. But, in many cases, so what?

Let's assume a horizontal radiator is 100% efficient.

wrong understanding of 'efficient'

how about a rewrite of the OP

'vertical radiators are less *effective* at heating a room than
horizontal ones'

So, you choose a slightly larger one

It has to be more than slightly larger.

Sure, there is likely plenty of spare vertical space.

But how much of the time does that efficiency matter? I suspect a large
proportion of radiators are throttled by a TRV. Further, if the
radiator can cope on the coldest days, it probably has plenty of
capacity in hand for most of the rest of the year.

Dropping efficiency to, I suggest, 90% would only really affect that
small period during which the absolute maximum output is required.

"Tim Streater" wrote in message
...
On 06 May 2021 at 13:35:57 BST, Andrew
wrote:

On 06/05/2021 13:10, Fredxx wrote:
On 06/05/2021 12:55, jon wrote:

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.
For conventional central heating radiators most heat-loss is through
convection. Air is a poor conductor.
It seems there is less overall air flow for a tall radiator than long
for a radiator with the same area and construction.
So hardly nonsense.

Try telling that to the female who has decided that "we need" vertical
designer rads.

Bugger the designer aspect. It all depends on available wall space. A tall
rad
of a given width should put out more heat than a shorter one.

Yes, but verticals are often used when there is a shortage of
horizontal space and verticals dont work under windows.

Fredxx wrote
Rod Speed wrote
Robin wrote
jon wrote

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

As I think I said the last time this came up, my physics is nowhere near
good enough to decide "by inspection" whether a vertical or horizontal
radiator is better at transferring heat to a room.

Yes, you clearly have that problem. Plenty of us dont.

I don't know why you say that,

Because its true ? Novel concept I realise.

as the chimney effect can sometimes be very good at providing a good
airflow.

They both have that. The difference is that the
horizontal radiators have the air moving over
much less of the radiator so the radiator has
more cold air moving over it and so you will
see more heat moving out of the radiator
into the airstream.

So at first sight it's not obvious which orientation is best.

Only for those who dont have a clue about the basics.

Only those with hindsight will think differently.

Wrong.

And (like some others)

Who have the same problem.

I saw too many /known/ unknowns - e.g laminar flow? temperature of air
exiting top? chimney effect? - quite apart from the possible unknown^2

None of that matters. What matters is the vertical distance.

There is no chimney effect with a radiator.

The gap between the radiator and the wall and radiator height will
determine air speed over the radiator.

But that isnt different with the two types of radiator.

What matter is the distance that the cold air at the bottom of
the radiator moves over before it gets to the top of the radiator.

If you think differently, please feel free to cite an explanation why this
isn't the case.

Just did. And dont need a cite, just an explanation.

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ

"Rod Speed" wrote in message
...
Fredxx wrote
Rod Speed wrote
Robin wrote
jon wrote

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

As I think I said the last time this came up, my physics is nowhere
near good enough to decide "by inspection" whether a vertical or
horizontal radiator is better at transferring heat to a room.

Yes, you clearly have that problem. Plenty of us dont.

I don't know why you say that,

Because its true ? Novel concept I realise.

as the chimney effect can sometimes be very good at providing a good
airflow.

They both have that. The difference is that the
horizontal radiators have the air moving over
much less of the radiator so the radiator has
more cold air moving over it and so you will
see more heat moving out of the radiator
into the airstream.

So at first sight it's not obvious which orientation is best.

Only for those who dont have a clue about the basics.

Only those with hindsight will think differently.

Wrong.

And (like some others)

Who have the same problem.

I saw too many /known/ unknowns - e.g laminar flow? temperature of air
exiting top? chimney effect? - quite apart from the possible unknown^2

None of that matters. What matters is the vertical distance.

There is no chimney effect with a radiator.

The gap between the radiator and the wall and radiator height will
determine air speed over the radiator.

But that isnt different with the two types of radiator.

What matter is the distance that the cold air at the bottom of
the radiator moves over before it gets to the top of the radiator.

If you think differently, please feel free to cite an explanation why
this isn't the case.

Just did. And dont need a cite, just an explanation.

A better way of saying it is that with the top half of the
radiator. it has already heated air moving over it so will
move heat out of the radiator more poorly. There is a
lot more surface area like that with a vertical radiator.

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ

On Fri, 7 May 2021 02:54:46 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the trolling senile pest's latest troll**** unread

--
Senile Rodent about himself:
"I was involved in the design of a computer OS"
MID:

LOL

On Fri, 7 May 2021 02:45:42 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

That¢s very arguable indeed.

What is NOT "arguable" for you, abnormal cantankerous senile troll?

--
Sqwertz to Rodent Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On Fri, 7 May 2021 03:29:47 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the trolling senile asshole's latest troll**** unread

Quarrelling the **** out of this group again (at 03:29 in Australia LOL),
you demented trolling senile asshole?

--
Richard addressing senile Rodent Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

On 06/05/2021 14:47, Tim Streater wrote:

Bugger the designer aspect. It all depends on available wall space. A tall rad
of a given width should put out more heat than a shorter one.


But it may be uncomfortably hot if anyone has to sit close to it if
fitted to an internal wall.



--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 06/05/2021 18:29, Rod Speed wrote:
Fredxx wrote
Rod Speed wrote
Robin wrote
jon wrote

What is this nonsense, heat is dissipated by radiation, convection
or conduction so how come efficiency becomes a problem.

As I think I said the last time this came up, my physics is nowhere
near good enough to decide "by inspection" whether a vertical or
horizontal radiator is better at transferring heat to a room.

Yes, you clearly have that problem. Plenty of us dont.

I don't know why you say that,

Because its true ?Â* Novel concept I realise.

as the chimney effect can sometimes be very good at providing a good
airflow.

They both have that. The difference is that the
horizontal radiators have the air moving over
much less of the radiator so the radiator has
more cold air moving over it and so you will
see more heat moving out of the radiator
into the airstream.

So at first sight it's not obvious which orientation is best.

Only for those who dont have a clue about the basics.

Only those with hindsight will think differently.

Wrong.

And (like some others)

Who have the same problem.

I saw too many /known/ unknowns - e.g laminar flow? temperature of
air exiting top? chimney effect? - quite apart from the possible
unknown^2

None of that matters. What matters is the vertical distance.

There is no chimney effect with a radiator.

The gap between the radiator and the wall and radiator height will
determine air speed over the radiator.

But that isnt different with the two types of radiator.

What matter is the distance that the cold air at the bottom of
the radiator moves over before it gets to the top of the radiator.

If you think differently, please feel free to cite an explanation why
this isn't the case.

Just did. And dont need a cite, just an explanation.

You haven't explained why a larger temperature difference within an
enclosed space such as a flue or the space around a radiator won't
create a bigger draught when we know the opposite is generally true.

This paper for instance:
http://cit.edu.ly/wp-content/uploads/2018/02/15-091.pdf

suggests the optimum aspect ratio of the radiator is highly dependent on
wall height.

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ

Fredxx wrote
Rod Speed wrote
Fredxx wrote
Rod Speed wrote
Robin wrote
jon wrote

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

As I think I said the last time this came up, my physics is nowhere
near good enough to decide "by inspection" whether a vertical or
horizontal radiator is better at transferring heat to a room.

Yes, you clearly have that problem. Plenty of us dont.

I don't know why you say that,

Because its true ? Novel concept I realise.

as the chimney effect can sometimes be very good at providing a good
airflow.

They both have that. The difference is that the
horizontal radiators have the air moving over
much less of the radiator so the radiator has
more cold air moving over it and so you will
see more heat moving out of the radiator
into the airstream.

So at first sight it's not obvious which orientation is best.

Only for those who dont have a clue about the basics.

Only those with hindsight will think differently.

Wrong.

And (like some others)

Who have the same problem.

I saw too many /known/ unknowns - e.g laminar flow? temperature of air
exiting top? chimney effect? - quite apart from the possible unknown^2

None of that matters. What matters is the vertical distance.

There is no chimney effect with a radiator.

The gap between the radiator and the wall and radiator height will
determine air speed over the radiator.

But that isnt different with the two types of radiator.

What matter is the distance that the cold air at the bottom of
the radiator moves over before it gets to the top of the radiator.

If you think differently, please feel free to cite an explanation why
this isn't the case.

Just did. And dont need a cite, just an explanation.

You haven't explained why a larger temperature difference within an
enclosed space such as a flue or the space around a radiator won't create
a bigger draught when we know the opposite is generally true.

That isnt true with the front of the radiator or even with
the back of the radiator either given that the draught
will be much more restricted with the vertical radiator.

This paper for instance:
http://cit.edu.ly/wp-content/uploads/2018/02/15-091.pdf

suggests the optimum aspect ratio of the radiator is highly dependent on
wall height.

Even that is unclear. A very wide horizontal
radiator would work better as far as heating the
air is concerned. Just not practical in homes.

And you have the other consideration,
a very wide radiator would see a big
difference in surface temp between
the ends of the radiator.

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ

On 06/05/2021 20:08, Rod Speed wrote:
Fredxx wrote

snip

suggests the optimum aspect ratio of the radiator is highly dependent
on wall height.

Even that is unclear.

The paper makes it clear.

A very wide horizontal
radiator would work better as far as heating the
air is concerned.

Not in all cases, as demonstrated by the paper in real home situations.

"Fredxx" wrote in message
...
On 06/05/2021 18:29, Rod Speed wrote:
Fredxx wrote
Rod Speed wrote
Robin wrote
jon wrote

What is this nonsense, heat is dissipated by radiation, convection or
conduction so how come efficiency becomes a problem.

As I think I said the last time this came up, my physics is nowhere
near good enough to decide "by inspection" whether a vertical or
horizontal radiator is better at transferring heat to a room.

Yes, you clearly have that problem. Plenty of us dont.

I don't know why you say that,

Because its true ? Novel concept I realise.

as the chimney effect can sometimes be very good at providing a good
airflow.

They both have that. The difference is that the
horizontal radiators have the air moving over
much less of the radiator so the radiator has
more cold air moving over it and so you will
see more heat moving out of the radiator
into the airstream.

So at first sight it's not obvious which orientation is best.

Only for those who dont have a clue about the basics.

Only those with hindsight will think differently.

Wrong.

And (like some others)

Who have the same problem.

I saw too many /known/ unknowns - e.g laminar flow? temperature of air
exiting top? chimney effect? - quite apart from the possible unknown^2

None of that matters. What matters is the vertical distance.

There is no chimney effect with a radiator.

The gap between the radiator and the wall and radiator height will
determine air speed over the radiator.

But that isnt different with the two types of radiator.

What matter is the distance that the cold air at the bottom of
the radiator moves over before it gets to the top of the radiator.

If you think differently, please feel free to cite an explanation why
this isn't the case.

Just did. And dont need a cite, just an explanation.

You haven't explained why a larger temperature difference within an
enclosed space such as a flue or the space around a radiator won't create
a bigger draught when we know the opposite is generally true.

This paper for instance:
http://cit.edu.ly/wp-content/uploads/2018/02/15-091.pdf

University of Zawia, hardly one of the world's great universitys.
And they only use aspect ratios up to 2 and no verticals, so
none of that paper is relevant anyway.

suggests the optimum aspect ratio of the radiator is highly dependent on
wall height.

Ah yes:

https://groups.google.com/g/uk.d-i-y...m/lwVTe0U-U3YJ