On Tue, 11 Oct 2022 09:16:15 -0000 (UTC)
Recliner <recliner.usenet@gmail.com> wrote:
>It's a bit like the many people who think that the flash should be used
>whenever pictures are taken in low light, even in large stadiums or
>firework displays. Or, even worse, when taking pictures of objects behind
>glass.

I was at edinburgh castle many years ago and overhead a yank taking a picture
of the city from the wall asking her friend if she should use the flash.

On Tue, 11 Oct 2022 09:41:03 -0000 (UTC)
Tweed <usenet.tweed@gmail.com> wrote:
>Recliner <recliner.usenet@gmail.com> wrote:
>> Some years ago I had an argument with an accountant colleague who thought
>> that leaving a fun running in a hot room would cool it down, so it should
>> be left on, even if no-one was in the room. I simply couldn't convince him
>> that doing that would actually make the room even hotter.
>>
>The lack of even a basic understanding of science is the undoing of a huge
>chunk of the population.

A lot of them sit in boardrooms.

On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
<recliner.usenet@gmail.com> wrote:

>Ken <ken@birchanger.com> wrote:
>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>> wrote:
>>
>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>
>>>>
>>>> What power are the fans, typically? Are we just considering the waste heat
>>>> from the motors, or also the contribution of the energy they impart to the
>>>> moving air?
>>>
>>> Both, I think.
>>>
>> Of course. It doesn't matter how efficient or inefficient the fans
>> are. They produce waste heat via resistive heating and friction and
>> any useful work they do on the air increases its temperature.
>>
>
>So, while the fans briefly cool the people walking past them, they actually
>warm up everyone else in the station, who just experiences the extra heat
>without benefiting from the breeze.

That was my original point. I accept that the amount of extra energy
turned into heat is quite small, but I wonder if the fact that
electric fans actually heat a closed environment was known to TfL, and
they considered the transient relief to some passengers worth it; was
known but the optics were good; or did they not know?
The last of these isn't far fetched. I know of people who have fitted
ceiling fans to rooms that are left on all day because they believe
the rooms will be cooled.

Ken <ken@birchanger.com> wrote:
> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
> <recliner.usenet@gmail.com> wrote:
>
>> Ken <ken@birchanger.com> wrote:
>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>> wrote:
>>>
>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>
>>>>>
>>>>> What power are the fans, typically? Are we just considering the waste heat
>>>>> from the motors, or also the contribution of the energy they impart to the
>>>>> moving air?
>>>>
>>>> Both, I think.
>>>>
>>> Of course. It doesn't matter how efficient or inefficient the fans
>>> are. They produce waste heat via resistive heating and friction and
>>> any useful work they do on the air increases its temperature.
>>>
>>
>> So, while the fans briefly cool the people walking past them, they actually
>> warm up everyone else in the station, who just experiences the extra heat
>> without benefiting from the breeze.
>
> That was my original point. I accept that the amount of extra energy
> turned into heat is quite small, but I wonder if the fact that
> electric fans actually heat a closed environment was known to TfL, and
> they considered the transient relief to some passengers worth it; was
> known but the optics were good; or did they not know?
> The last of these isn't far fetched. I know of people who have fitted
> ceiling fans to rooms that are left on all day because they believe
> the rooms will be cooled.
>

TfL is well aware of the issues and the physics, but is using these cheap,
visible, noisy fans to show that it's doing *something * while it works on
the much harder, more expensive long-term solutions.

I'd like to hear more about the project to use the groundwater that's
constantly pumped out of the system as a heat sink. The cheap approach is
to just blow warm ambient air through heat exchangers with the cool water,
but heat pumps would be more effective. I know old disused lift shafts are
also used for surface ventilation in many cases.

The Victoria line has particular issues, as it doesn't get the benefit of
the piston effect, and its stations were built with escalators, so there
aren't disused old lift shafts to re-use for surface ventilation. It also
has a very frequent schedule, and very busy stations.

Recliner <recliner.usenet@gmail.com> wrote:
> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>> <Muttley@dastardlyhq.com> wrote:
>>>>>>> On 26 Sep 2022 13:08:17 +0100 (BST)
>>>>>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>>>>>> In uk.transport.london Ken <ken@birchanger.com> wrote:
>>>>>>>>> I'm not talking about the huge fans in ventilation shafts; I'm talking
>>>>>>>>> about the freestanding ones in passenger circulation areas. These
>>>>>>>>> don't move a molecule of air in or out of the system.
>>>>>>>>
>>>>>>>> But there are inevitably dead spots in the ventilation. There will be a
>>>>>>>> particular main flow from the shaft fans, but heat can build up in pockets
>>>>>>>> that aren't directly ventilated. Adding extra fans to mix the air around
>>>>>>>> smooths out temperature differences between (for example) the running
>>>>>>>> tunnels (which might be directly ventilated) and the platform cross-passages
>>>>>>>> and escalator lower tunnels (which might not). Plus it also makes a breeze
>>>>>>>> which is appreciated by passengers.
>>>>>>>
>>>>>>> The amount of air they move around is probably insignificant compared to
>>>>>>> the trains themselves. All they do is provide a breeze for pax walking past.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> I've always presumed that that's what they're for - to provide a breeze to
>>>>>> make the heat feel less unpleasant.
>>>>>
>>>>> Yes, they're just a low cost stop-gap until the temperatures can be reduced
>>>>> using better surface ventilation, or using ground water for cooling.
>>>>
>>>> Of course; at higher temperatures humans mostly use evaporative cooling -
>>>> we’d die at external temperatures anywhere near 37 C otherwise - and
>>>> increasing the airflow increases the cooling so long as the air doesn’t
>>>> have very high relative humidity.
>>>>
>>>
>>> Yes, but of course the powerful fans themselves contribute to the heat
>>> build-up in the system.
>>>
>>>
>>
>> What power are the fans, typically? Are we just considering the waste heat
>> from the motors, or also the contribution of the energy they impart to the
>> moving air?
>
> The total energy consumed by each fan (a few hundred watts) gets added to
> the heat in the system.
>
>>
>> How does the heat contribution of a handful of fans compare to that of
>> thousands of people and hundreds of trains?
>
> It's only a very small increment, but it's nevertheless contributing to the
> heating, rather than reducing it.
>
>

…whilst at the same time making the *perception* of the heat more bearable,
so a net win overall for passenger comfort.

Anna Noyd-Dryver

Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
> Recliner <recliner.usenet@gmail.com> wrote:
>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>> <Muttley@dastardlyhq.com> wrote:
>>>>>>>> On 26 Sep 2022 13:08:17 +0100 (BST)
>>>>>>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>>>>>>> In uk.transport.london Ken <ken@birchanger.com> wrote:
>>>>>>>>>> I'm not talking about the huge fans in ventilation shafts; I'm talking
>>>>>>>>>> about the freestanding ones in passenger circulation areas. These
>>>>>>>>>> don't move a molecule of air in or out of the system.
>>>>>>>>>
>>>>>>>>> But there are inevitably dead spots in the ventilation. There will be a
>>>>>>>>> particular main flow from the shaft fans, but heat can build up in pockets
>>>>>>>>> that aren't directly ventilated. Adding extra fans to mix the air around
>>>>>>>>> smooths out temperature differences between (for example) the running
>>>>>>>>> tunnels (which might be directly ventilated) and the platform cross-passages
>>>>>>>>> and escalator lower tunnels (which might not). Plus it also makes a breeze
>>>>>>>>> which is appreciated by passengers.
>>>>>>>>
>>>>>>>> The amount of air they move around is probably insignificant compared to
>>>>>>>> the trains themselves. All they do is provide a breeze for pax walking past.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> I've always presumed that that's what they're for - to provide a breeze to
>>>>>>> make the heat feel less unpleasant.
>>>>>>
>>>>>> Yes, they're just a low cost stop-gap until the temperatures can be reduced
>>>>>> using better surface ventilation, or using ground water for cooling.
>>>>>
>>>>> Of course; at higher temperatures humans mostly use evaporative cooling -
>>>>> we’d die at external temperatures anywhere near 37 C otherwise - and
>>>>> increasing the airflow increases the cooling so long as the air doesn’t
>>>>> have very high relative humidity.
>>>>>
>>>>
>>>> Yes, but of course the powerful fans themselves contribute to the heat
>>>> build-up in the system.
>>>>
>>>>
>>>
>>> What power are the fans, typically? Are we just considering the waste heat
>>> from the motors, or also the contribution of the energy they impart to the
>>> moving air?
>>
>> The total energy consumed by each fan (a few hundred watts) gets added to
>> the heat in the system.
>>
>>>
>>> How does the heat contribution of a handful of fans compare to that of
>>> thousands of people and hundreds of trains?
>>
>> It's only a very small increment, but it's nevertheless contributing to the
>> heating, rather than reducing it.
>>
>>
>
> …whilst at the same time making the *perception* of the heat more bearable,

Only for those directly in front of the fan, but slightly worse for the
much larger number of others in the area.

> so a net win overall for passenger comfort.

I'm not so sure about that.

On 11/10/2022 10:16, Recliner wrote:
> Ken <ken@birchanger.com> wrote:
>> On Mon, 10 Oct 2022 09:57:40 -0000 (UTC), Recliner
>> <recliner.usenet@gmail.com> wrote:
>>
>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>> <Muttley@dastardlyhq.com> wrote:
>>>>>>> On 26 Sep 2022 13:08:17 +0100 (BST)
>>>>>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>>>>>> In uk.transport.london Ken <ken@birchanger.com> wrote:
>>>>>>>>> I'm not talking about the huge fans in ventilation shafts; I'm talking
>>>>>>>>> about the freestanding ones in passenger circulation areas. These
>>>>>>>>> don't move a molecule of air in or out of the system.
>>>>>>>>
>>>>>>>> But there are inevitably dead spots in the ventilation. There will be a
>>>>>>>> particular main flow from the shaft fans, but heat can build up in pockets
>>>>>>>> that aren't directly ventilated. Adding extra fans to mix the air around
>>>>>>>> smooths out temperature differences between (for example) the running
>>>>>>>> tunnels (which might be directly ventilated) and the platform cross-passages
>>>>>>>> and escalator lower tunnels (which might not). Plus it also makes a breeze
>>>>>>>> which is appreciated by passengers.
>>>>>>>
>>>>>>> The amount of air they move around is probably insignificant compared to
>>>>>>> the trains themselves. All they do is provide a breeze for pax walking past.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> I've always presumed that that's what they're for - to provide a breeze to
>>>>>> make the heat feel less unpleasant.
>>>>>
>>>>> Yes, they're just a low cost stop-gap until the temperatures can be reduced
>>>>> using better surface ventilation, or using ground water for cooling.
>>>>
>>>> Of course; at higher temperatures humans mostly use evaporative cooling -
>>>> we’d die at external temperatures anywhere near 37 C otherwise - and
>>>> increasing the airflow increases the cooling so long as the air doesn’t
>>>> have very high relative humidity.
>>>>
>>>
>>> Yes, but of course the powerful fans themselves contribute to the heat
>>> build-up in the system.
>>
>> Which was my original point! It's taken some time.
>>
>
> Some years ago I had an argument with an accountant colleague who thought
> that leaving a fun running in a hot room would cool it down, so it should
> be left on, even if no-one was in the room. I simply couldn't convince him
> that doing that would actually make the room even hotter.
>
> It's a bit like the many people who think that the flash should be used
> whenever pictures are taken in low light, even in large stadiums or
> firework displays. Or, even worse, when taking pictures of objects behind
> glass.
>

Went to a Son et Lumiere production at Dover Castle many years ago,
there were people trying to photograph the lighting effects with flash!

--
Graeme Wall
This account not read.

On 11/10/2022 16:33, Muttley@dastardlyhq.com wrote:
> On Tue, 11 Oct 2022 09:16:15 -0000 (UTC)
> Recliner <recliner.usenet@gmail.com> wrote:
>> It's a bit like the many people who think that the flash should be used
>> whenever pictures are taken in low light, even in large stadiums or
>> firework displays. Or, even worse, when taking pictures of objects behind
>> glass.
>
> I was at edinburgh castle many years ago and overhead a yank taking a picture
> of the city from the wall asking her friend if she should use the flash.
>

The other side is trying to convince people to use flash when taking
photos of people with the sun behind them.

--
Graeme Wall
This account not read.

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 11/10/2022 16:33, Muttley@dastardlyhq.com wrote:
>> On Tue, 11 Oct 2022 09:16:15 -0000 (UTC)
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> It's a bit like the many people who think that the flash should be used
>>> whenever pictures are taken in low light, even in large stadiums or
>>> firework displays. Or, even worse, when taking pictures of objects behind
>>> glass.
>>
>> I was at edinburgh castle many years ago and overhead a yank taking a picture
>> of the city from the wall asking her friend if she should use the flash.
>>
>
> The other side is trying to convince people to use flash when taking
> photos of people with the sun behind them.
>

Yes, I occasionally get asked to take pictures of people while out and
about. They are quite surprised when I try to persuade them not to be
photographed with the sun behind them!

In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
2022, Recliner <recliner.usenet@gmail.com> remarked:
>Ken <ken@birchanger.com> wrote:
>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>> <recliner.usenet@gmail.com> wrote:
>>
>>> Ken <ken@birchanger.com> wrote:
>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>> wrote:
>>>>
>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>
>>>>>>
>>>>>> What power are the fans, typically? Are we just considering the
>>>>>>waste heat
>>>>>> from the motors, or also the contribution of the energy they
>>>>>>impart to the
>>>>>> moving air?
>>>>>
>>>>> Both, I think.
>>>>>
>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>> are. They produce waste heat via resistive heating and friction and
>>>> any useful work they do on the air increases its temperature.
>>>>
>>>
>>> So, while the fans briefly cool the people walking past them, they actually
>>> warm up everyone else in the station, who just experiences the extra heat
>>> without benefiting from the breeze.
>>
>> That was my original point. I accept that the amount of extra energy
>> turned into heat is quite small, but I wonder if the fact that
>> electric fans actually heat a closed environment was known to TfL, and
>> they considered the transient relief to some passengers worth it; was
>> known but the optics were good; or did they not know?
>> The last of these isn't far fetched. I know of people who have fitted
>> ceiling fans to rooms that are left on all day because they believe
>> the rooms will be cooled.
>
>TfL is well aware of the issues and the physics,

Of course they are. It's preposterous anyone thinks they aren't.

>but is using these cheap,
>visible, noisy fans to show that it's doing *something * while it works on
>the much harder, more expensive long-term solutions.
>
>I'd like to hear more about the project to use the groundwater that's
>constantly pumped out of the system as a heat sink. The cheap approach is
>to just blow warm ambient air through heat exchangers with the cool water,
>but heat pumps would be more effective. I know old disused lift shafts are
>also used for surface ventilation in many cases.
>
>The Victoria line has particular issues, as it doesn't get the benefit of
>the piston effect, and its stations were built with escalators, so there
>aren't disused old lift shafts to re-use for surface ventilation.

Although many of the stations on the line do have old lift shafts, and
even purpose-built ventilation systems. Here's a really rather big one
at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6

>It also has a very frequent schedule, and very busy stations.

--
Roland Perry

Roland Perry <roland@perry.co.uk> wrote:
> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>> Ken <ken@birchanger.com> wrote:
>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>> <recliner.usenet@gmail.com> wrote:
>>>
>>>> Ken <ken@birchanger.com> wrote:
>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>> wrote:
>>>>>
>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>
>>>>>>>
>>>>>>> What power are the fans, typically? Are we just considering the
>>>>>>> waste heat
>>>>>>> from the motors, or also the contribution of the energy they
>>>>>>> impart to the
>>>>>>> moving air?
>>>>>>
>>>>>> Both, I think.
>>>>>>
>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>> are. They produce waste heat via resistive heating and friction and
>>>>> any useful work they do on the air increases its temperature.
>>>>>
>>>>
>>>> So, while the fans briefly cool the people walking past them, they actually
>>>> warm up everyone else in the station, who just experiences the extra heat
>>>> without benefiting from the breeze.
>>>
>>> That was my original point. I accept that the amount of extra energy
>>> turned into heat is quite small, but I wonder if the fact that
>>> electric fans actually heat a closed environment was known to TfL, and
>>> they considered the transient relief to some passengers worth it; was
>>> known but the optics were good; or did they not know?
>>> The last of these isn't far fetched. I know of people who have fitted
>>> ceiling fans to rooms that are left on all day because they believe
>>> the rooms will be cooled.
>>
>> TfL is well aware of the issues and the physics,
>
> Of course they are. It's preposterous anyone thinks they aren't.
>
>> but is using these cheap,
>> visible, noisy fans to show that it's doing *something * while it works on
>> the much harder, more expensive long-term solutions.
>>
>> I'd like to hear more about the project to use the groundwater that's
>> constantly pumped out of the system as a heat sink. The cheap approach is
>> to just blow warm ambient air through heat exchangers with the cool water,
>> but heat pumps would be more effective. I know old disused lift shafts are
>> also used for surface ventilation in many cases.
>>
>> The Victoria line has particular issues, as it doesn't get the benefit of
>> the piston effect, and its stations were built with escalators, so there
>> aren't disused old lift shafts to re-use for surface ventilation.
>
> Although many of the stations on the line do have old lift shafts, and
> even purpose-built ventilation systems. Here's a really rather big one
> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6

Yes, that's a good example, but, self-evidently, more are needed.

The size of that shaft illustrates how they're hard to fit into a busy
urban landscape. The ideal site is an abandoned surface station building
(eg, when the surface building is relocated when the original lifts are
replaced by escalators or an original station was simply closed), but the
Victoria line is too new to have any.

Recliner <recliner.usenet@gmail.com> wrote:
> Roland Perry <roland@perry.co.uk> wrote:
>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>> Ken <ken@birchanger.com> wrote:
>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>> <recliner.usenet@gmail.com> wrote:
>>>>
>>>>> Ken <ken@birchanger.com> wrote:
>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>> wrote:
>>>>>>
>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>
>>>>>>>>
>>>>>>>> What power are the fans, typically? Are we just considering the
>>>>>>>> waste heat
>>>>>>>> from the motors, or also the contribution of the energy they
>>>>>>>> impart to the
>>>>>>>> moving air?
>>>>>>>
>>>>>>> Both, I think.
>>>>>>>
>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>> any useful work they do on the air increases its temperature.
>>>>>>
>>>>>
>>>>> So, while the fans briefly cool the people walking past them, they actually
>>>>> warm up everyone else in the station, who just experiences the extra heat
>>>>> without benefiting from the breeze.
>>>>
>>>> That was my original point. I accept that the amount of extra energy
>>>> turned into heat is quite small, but I wonder if the fact that
>>>> electric fans actually heat a closed environment was known to TfL, and
>>>> they considered the transient relief to some passengers worth it; was
>>>> known but the optics were good; or did they not know?
>>>> The last of these isn't far fetched. I know of people who have fitted
>>>> ceiling fans to rooms that are left on all day because they believe
>>>> the rooms will be cooled.
>>>
>>> TfL is well aware of the issues and the physics,
>>
>> Of course they are. It's preposterous anyone thinks they aren't.
>>
>>> but is using these cheap,
>>> visible, noisy fans to show that it's doing *something * while it works on
>>> the much harder, more expensive long-term solutions.
>>>
>>> I'd like to hear more about the project to use the groundwater that's
>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>> to just blow warm ambient air through heat exchangers with the cool water,
>>> but heat pumps would be more effective. I know old disused lift shafts are
>>> also used for surface ventilation in many cases.
>>>
>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>> the piston effect, and its stations were built with escalators, so there
>>> aren't disused old lift shafts to re-use for surface ventilation.
>>
>> Although many of the stations on the line do have old lift shafts, and
>> even purpose-built ventilation systems. Here's a really rather big one
>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>
> Yes, that's a good example, but, self-evidently, more are needed.
>
> The size of that shaft illustrates how they're hard to fit into a busy
> urban landscape. The ideal site is an abandoned surface station building
> (eg, when the surface building is relocated when the original lifts are
> replaced by escalators or an original station was simply closed), but the
> Victoria line is too new to have any.
>

But doesn’t the Victoria line share stations with many older lines? There’s
lots of scope to move air in great volumes inside the stations and up
through existing vent shafts. On my tour of Charing Cross (not Victoria I
know) there was shown all sorts of cross line vent tunnels, including the
out of service Jubilee spur. We had a wander down one of them.

Recliner <recliner.usenet@gmail.com> wrote:
> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>> <Muttley@dastardlyhq.com> wrote:
>>>>>>>>> On 26 Sep 2022 13:08:17 +0100 (BST)
>>>>>>>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>>>>>>>> In uk.transport.london Ken <ken@birchanger.com> wrote:
>>>>>>>>>>> I'm not talking about the huge fans in ventilation shafts; I'm talking
>>>>>>>>>>> about the freestanding ones in passenger circulation areas. These
>>>>>>>>>>> don't move a molecule of air in or out of the system.
>>>>>>>>>>
>>>>>>>>>> But there are inevitably dead spots in the ventilation. There will be a
>>>>>>>>>> particular main flow from the shaft fans, but heat can build up in pockets
>>>>>>>>>> that aren't directly ventilated. Adding extra fans to mix the air around
>>>>>>>>>> smooths out temperature differences between (for example) the running
>>>>>>>>>> tunnels (which might be directly ventilated) and the platform cross-passages
>>>>>>>>>> and escalator lower tunnels (which might not). Plus it also makes a breeze
>>>>>>>>>> which is appreciated by passengers.
>>>>>>>>>
>>>>>>>>> The amount of air they move around is probably insignificant compared to
>>>>>>>>> the trains themselves. All they do is provide a breeze for pax walking past.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>> I've always presumed that that's what they're for - to provide a breeze to
>>>>>>>> make the heat feel less unpleasant.
>>>>>>>
>>>>>>> Yes, they're just a low cost stop-gap until the temperatures can be reduced
>>>>>>> using better surface ventilation, or using ground water for cooling.
>>>>>>
>>>>>> Of course; at higher temperatures humans mostly use evaporative cooling -
>>>>>> we’d die at external temperatures anywhere near 37 C otherwise - and
>>>>>> increasing the airflow increases the cooling so long as the air doesn’t
>>>>>> have very high relative humidity.
>>>>>>
>>>>>
>>>>> Yes, but of course the powerful fans themselves contribute to the heat
>>>>> build-up in the system.
>>>>>
>>>>>
>>>>
>>>> What power are the fans, typically? Are we just considering the waste heat
>>>> from the motors, or also the contribution of the energy they impart to the
>>>> moving air?
>>>
>>> The total energy consumed by each fan (a few hundred watts) gets added to
>>> the heat in the system.
>>>
>>>>
>>>> How does the heat contribution of a handful of fans compare to that of
>>>> thousands of people and hundreds of trains?
>>>
>>> It's only a very small increment, but it's nevertheless contributing to the
>>> heating, rather than reducing it.
>>>
>>>
>>
>> …whilst at the same time making the *perception* of the heat more bearable,
>
> Only for those directly in front of the fan, but slightly worse for the
> much larger number of others in the area.
>
>> so a net win overall for passenger comfort.
>
> I'm not so sure about that.
>

Presumably you never fan yourself with a piece of paper (etc) when you're
feeling hot, for fear of infinitesimally increasing the overall
temperature?

Anna Noyd-Dryver

Tweed <usenet.tweed@gmail.com> wrote:
> Recliner <recliner.usenet@gmail.com> wrote:
>> Roland Perry <roland@perry.co.uk> wrote:
>>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>> Ken <ken@birchanger.com> wrote:
>>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>
>>>>>> Ken <ken@birchanger.com> wrote:
>>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>>
>>>>>>>>>
>>>>>>>>> What power are the fans, typically? Are we just considering the
>>>>>>>>> waste heat
>>>>>>>>> from the motors, or also the contribution of the energy they
>>>>>>>>> impart to the
>>>>>>>>> moving air?
>>>>>>>>
>>>>>>>> Both, I think.
>>>>>>>>
>>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>>> any useful work they do on the air increases its temperature.
>>>>>>>
>>>>>>
>>>>>> So, while the fans briefly cool the people walking past them, they actually
>>>>>> warm up everyone else in the station, who just experiences the extra heat
>>>>>> without benefiting from the breeze.
>>>>>
>>>>> That was my original point. I accept that the amount of extra energy
>>>>> turned into heat is quite small, but I wonder if the fact that
>>>>> electric fans actually heat a closed environment was known to TfL, and
>>>>> they considered the transient relief to some passengers worth it; was
>>>>> known but the optics were good; or did they not know?
>>>>> The last of these isn't far fetched. I know of people who have fitted
>>>>> ceiling fans to rooms that are left on all day because they believe
>>>>> the rooms will be cooled.
>>>>
>>>> TfL is well aware of the issues and the physics,
>>>
>>> Of course they are. It's preposterous anyone thinks they aren't.
>>>
>>>> but is using these cheap,
>>>> visible, noisy fans to show that it's doing *something * while it works on
>>>> the much harder, more expensive long-term solutions.
>>>>
>>>> I'd like to hear more about the project to use the groundwater that's
>>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>>> to just blow warm ambient air through heat exchangers with the cool water,
>>>> but heat pumps would be more effective. I know old disused lift shafts are
>>>> also used for surface ventilation in many cases.
>>>>
>>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>>> the piston effect, and its stations were built with escalators, so there
>>>> aren't disused old lift shafts to re-use for surface ventilation.
>>>
>>> Although many of the stations on the line do have old lift shafts, and
>>> even purpose-built ventilation systems. Here's a really rather big one
>>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>>
>> Yes, that's a good example, but, self-evidently, more are needed.
>>
>> The size of that shaft illustrates how they're hard to fit into a busy
>> urban landscape. The ideal site is an abandoned surface station building
>> (eg, when the surface building is relocated when the original lifts are
>> replaced by escalators or an original station was simply closed), but the
>> Victoria line is too new to have any.
>>
>
> But doesn’t the Victoria line share stations with many older lines? There’s
> lots of scope to move air in great volumes inside the stations and up
> through existing vent shafts. On my tour of Charing Cross (not Victoria I
> know) there was shown all sorts of cross line vent tunnels, including the
> out of service Jubilee spur. We had a wander down one of them.

Ideally, you want a direct ventilation shaft from the running tunnel to the
surface, not via station tunnels and another line.

Interestingly, despite the large ventilation shaft at King Cross, the
Victoria Line is still pretty hot there.

Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
> Recliner <recliner.usenet@gmail.com> wrote:
>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>>> <Muttley@dastardlyhq.com> wrote:
>>>>>>>>>> On 26 Sep 2022 13:08:17 +0100 (BST)
>>>>>>>>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>>>>>>>>> In uk.transport.london Ken <ken@birchanger.com> wrote:
>>>>>>>>>>>> I'm not talking about the huge fans in ventilation shafts; I'm talking
>>>>>>>>>>>> about the freestanding ones in passenger circulation areas. These
>>>>>>>>>>>> don't move a molecule of air in or out of the system.
>>>>>>>>>>>
>>>>>>>>>>> But there are inevitably dead spots in the ventilation. There will be a
>>>>>>>>>>> particular main flow from the shaft fans, but heat can build up in pockets
>>>>>>>>>>> that aren't directly ventilated. Adding extra fans to mix the air around
>>>>>>>>>>> smooths out temperature differences between (for example) the running
>>>>>>>>>>> tunnels (which might be directly ventilated) and the platform cross-passages
>>>>>>>>>>> and escalator lower tunnels (which might not). Plus it also makes a breeze
>>>>>>>>>>> which is appreciated by passengers.
>>>>>>>>>>
>>>>>>>>>> The amount of air they move around is probably insignificant compared to
>>>>>>>>>> the trains themselves. All they do is provide a breeze for pax walking past.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I've always presumed that that's what they're for - to provide a breeze to
>>>>>>>>> make the heat feel less unpleasant.
>>>>>>>>
>>>>>>>> Yes, they're just a low cost stop-gap until the temperatures can be reduced
>>>>>>>> using better surface ventilation, or using ground water for cooling.
>>>>>>>
>>>>>>> Of course; at higher temperatures humans mostly use evaporative cooling -
>>>>>>> we’d die at external temperatures anywhere near 37 C otherwise - and
>>>>>>> increasing the airflow increases the cooling so long as the air doesn’t
>>>>>>> have very high relative humidity.
>>>>>>>
>>>>>>
>>>>>> Yes, but of course the powerful fans themselves contribute to the heat
>>>>>> build-up in the system.
>>>>>>
>>>>>>
>>>>>
>>>>> What power are the fans, typically? Are we just considering the waste heat
>>>>> from the motors, or also the contribution of the energy they impart to the
>>>>> moving air?
>>>>
>>>> The total energy consumed by each fan (a few hundred watts) gets added to
>>>> the heat in the system.
>>>>
>>>>>
>>>>> How does the heat contribution of a handful of fans compare to that of
>>>>> thousands of people and hundreds of trains?
>>>>
>>>> It's only a very small increment, but it's nevertheless contributing to the
>>>> heating, rather than reducing it.
>>>>
>>>>
>>>
>>> …whilst at the same time making the *perception* of the heat more bearable,
>>
>> Only for those directly in front of the fan, but slightly worse for the
>> much larger number of others in the area.
>>
>>> so a net win overall for passenger comfort.
>>
>> I'm not so sure about that.
>>
>
> Presumably you never fan yourself with a piece of paper (etc) when you're
> feeling hot, for fear of infinitesimally increasing the overall
> temperature?
>

I happily use fans, but in ventilated spaces. Any energy contributed by the
fan doesn't build up.

The problem with the Victoria line in particular is that it doesn't have
enough ventilation, because of the lack of piston effect.

In message <ti5scu$1dc0d$2@dont-email.me>, at 08:03:42 on Wed, 12 Oct
2022, Recliner <recliner.usenet@gmail.com> remarked:
>Roland Perry <roland@perry.co.uk> wrote:
>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>> Ken <ken@birchanger.com> wrote:
>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>> <recliner.usenet@gmail.com> wrote:
>>>>
>>>>> Ken <ken@birchanger.com> wrote:
>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>> wrote:
>>>>>>
>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>
>>>>>>>>
>>>>>>>> What power are the fans, typically? Are we just considering the
>>>>>>>> waste heat
>>>>>>>> from the motors, or also the contribution of the energy they
>>>>>>>> impart to the
>>>>>>>> moving air?
>>>>>>>
>>>>>>> Both, I think.
>>>>>>>
>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>> any useful work they do on the air increases its temperature.
>>>>>>
>>>>>
>>>>> So, while the fans briefly cool the people walking past them, they
>>>>>actually
>>>>> warm up everyone else in the station, who just experiences the extra heat
>>>>> without benefiting from the breeze.
>>>>
>>>> That was my original point. I accept that the amount of extra energy
>>>> turned into heat is quite small, but I wonder if the fact that
>>>> electric fans actually heat a closed environment was known to TfL, and
>>>> they considered the transient relief to some passengers worth it; was
>>>> known but the optics were good; or did they not know?
>>>> The last of these isn't far fetched. I know of people who have fitted
>>>> ceiling fans to rooms that are left on all day because they believe
>>>> the rooms will be cooled.
>>>
>>> TfL is well aware of the issues and the physics,
>>
>> Of course they are. It's preposterous anyone thinks they aren't.
>>
>>> but is using these cheap,
>>> visible, noisy fans to show that it's doing *something * while it works on
>>> the much harder, more expensive long-term solutions.
>>>
>>> I'd like to hear more about the project to use the groundwater that's
>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>> to just blow warm ambient air through heat exchangers with the cool water,
>>> but heat pumps would be more effective. I know old disused lift shafts are
>>> also used for surface ventilation in many cases.
>>>
>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>> the piston effect, and its stations were built with escalators, so there
>>> aren't disused old lift shafts to re-use for surface ventilation.
>>
>> Although many of the stations on the line do have old lift shafts, and
>> even purpose-built ventilation systems. Here's a really rather big one
>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>
>Yes, that's a good example, but, self-evidently, more are needed.
>
>The size of that shaft illustrates how they're hard to fit into a busy
>urban landscape.

I think it's trendy to call it "the public realm" m'lud.

>The ideal site is an abandoned surface station building (eg, when the
>surface building is relocated when the original lifts are replaced by
>escalators or an original station was simply closed), but the Victoria
>line is too new to have any.

https://goo.gl/maps/4oJmzZW2aNCmhCQJ6 perhaps?
--
Roland Perry

On Tue, 11 Oct 2022 21:25:44 +0100, Graeme Wall
<rail@greywall.demon.co.uk> wrote:

>On 11/10/2022 16:33, Muttley@dastardlyhq.com wrote:
>> On Tue, 11 Oct 2022 09:16:15 -0000 (UTC)
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> It's a bit like the many people who think that the flash should be used
>>> whenever pictures are taken in low light, even in large stadiums or
>>> firework displays. Or, even worse, when taking pictures of objects behind
>>> glass.
>>
>> I was at edinburgh castle many years ago and overhead a yank taking a picture
>> of the city from the wall asking her friend if she should use the flash.
>>
>
>The other side is trying to convince people to use flash when taking
>photos of people with the sun behind them.

I've tried. My phone camera decides that turning the flash ON should
be ignored if it thinks it's light enough.

In message <ti60bg$1e9ta$1@dont-email.me>, at 09:11:12 on Wed, 12 Oct
2022, Tweed <usenet.tweed@gmail.com> remarked:
>Recliner <recliner.usenet@gmail.com> wrote:
>> Roland Perry <roland@perry.co.uk> wrote:
>>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>> Ken <ken@birchanger.com> wrote:
>>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>
>>>>>> Ken <ken@birchanger.com> wrote:
>>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>>
>>>>>>>>>
>>>>>>>>> What power are the fans, typically? Are we just considering
>>>>>>>>> waste heat from the motors, or also the contribution of the
>>>>>>>>>energy they impart to the moving air?
>>>>>>>>
>>>>>>>> Both, I think.
>>>>>>>>
>>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>>> any useful work they do on the air increases its temperature.
>>>>>>
>>>>>> So, while the fans briefly cool the people walking past them,
>>>>>>they actually warm up everyone else in the station, who just
>>>>>>experiences the extra heat without benefiting from the breeze.
>>>>>
>>>>> That was my original point. I accept that the amount of extra energy
>>>>> turned into heat is quite small, but I wonder if the fact that
>>>>> electric fans actually heat a closed environment was known to TfL, and
>>>>> they considered the transient relief to some passengers worth it; was
>>>>> known but the optics were good; or did they not know?
>>>>> The last of these isn't far fetched. I know of people who have fitted
>>>>> ceiling fans to rooms that are left on all day because they believe
>>>>> the rooms will be cooled.
>>>>
>>>> TfL is well aware of the issues and the physics,
>>>
>>> Of course they are. It's preposterous anyone thinks they aren't.
>>>
>>>> but is using these cheap,
>>>> visible, noisy fans to show that it's doing *something * while it works on
>>>> the much harder, more expensive long-term solutions.
>>>>
>>>> I'd like to hear more about the project to use the groundwater that's
>>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>>> to just blow warm ambient air through heat exchangers with the cool water,
>>>> but heat pumps would be more effective. I know old disused lift shafts are
>>>> also used for surface ventilation in many cases.
>>>>
>>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>>> the piston effect, and its stations were built with escalators, so there
>>>> aren't disused old lift shafts to re-use for surface ventilation.
>>>
>>> Although many of the stations on the line do have old lift shafts, and
>>> even purpose-built ventilation systems. Here's a really rather big one
>>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>>
>> Yes, that's a good example, but, self-evidently, more are needed.
>>
>> The size of that shaft illustrates how they're hard to fit into a busy
>> urban landscape. The ideal site is an abandoned surface station building
>> (eg, when the surface building is relocated when the original lifts are
>> replaced by escalators or an original station was simply closed), but the
>> Victoria line is too new to have any.
>
>But doesn’t the Victoria line share stations with many older lines? There’s
>lots of scope to move air in great volumes inside the stations and up
>through existing vent shafts. On my tour of Charing Cross (not Victoria I
>know) there was shown all sorts of cross line vent tunnels, including the
>out of service Jubilee spur. We had a wander down one of them.

Ditto London Bridge, but the abandoned entrance building has now been
redeveloped post-Shard. But the ventilation shaft has been re-born:
https://goo.gl/maps/pxvkjM5XSpYpn1fs5
--
Roland Perry

On 12/10/2022 10:41, Ken wrote:
> On Tue, 11 Oct 2022 21:25:44 +0100, Graeme Wall
> <rail@greywall.demon.co.uk> wrote:
>
>> On 11/10/2022 16:33, Muttley@dastardlyhq.com wrote:
>>> On Tue, 11 Oct 2022 09:16:15 -0000 (UTC)
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> It's a bit like the many people who think that the flash should be used
>>>> whenever pictures are taken in low light, even in large stadiums or
>>>> firework displays. Or, even worse, when taking pictures of objects behind
>>>> glass.
>>>
>>> I was at edinburgh castle many years ago and overhead a yank taking a picture
>>> of the city from the wall asking her friend if she should use the flash.
>>>
>>
>> The other side is trying to convince people to use flash when taking
>> photos of people with the sun behind them.
>
> I've tried. My phone camera decides that turning the flash ON should
> be ignored if it thinks it's light enough.

Ah, I was referring to people using proper™ cameras, didn't know that
about the phone flash.

--
Graeme Wall
This account not read.

Roland Perry <roland@perry.co.uk> wrote:
> In message <ti5scu$1dc0d$2@dont-email.me>, at 08:03:42 on Wed, 12 Oct
> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>> Roland Perry <roland@perry.co.uk> wrote:
>>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>> Ken <ken@birchanger.com> wrote:
>>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>
>>>>>> Ken <ken@birchanger.com> wrote:
>>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>>
>>>>>>>>>
>>>>>>>>> What power are the fans, typically? Are we just considering the
>>>>>>>>> waste heat
>>>>>>>>> from the motors, or also the contribution of the energy they
>>>>>>>>> impart to the
>>>>>>>>> moving air?
>>>>>>>>
>>>>>>>> Both, I think.
>>>>>>>>
>>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>>> any useful work they do on the air increases its temperature.
>>>>>>>
>>>>>>
>>>>>> So, while the fans briefly cool the people walking past them, they
>>>>>> actually
>>>>>> warm up everyone else in the station, who just experiences the extra heat
>>>>>> without benefiting from the breeze.
>>>>>
>>>>> That was my original point. I accept that the amount of extra energy
>>>>> turned into heat is quite small, but I wonder if the fact that
>>>>> electric fans actually heat a closed environment was known to TfL, and
>>>>> they considered the transient relief to some passengers worth it; was
>>>>> known but the optics were good; or did they not know?
>>>>> The last of these isn't far fetched. I know of people who have fitted
>>>>> ceiling fans to rooms that are left on all day because they believe
>>>>> the rooms will be cooled.
>>>>
>>>> TfL is well aware of the issues and the physics,
>>>
>>> Of course they are. It's preposterous anyone thinks they aren't.
>>>
>>>> but is using these cheap,
>>>> visible, noisy fans to show that it's doing *something * while it works on
>>>> the much harder, more expensive long-term solutions.
>>>>
>>>> I'd like to hear more about the project to use the groundwater that's
>>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>>> to just blow warm ambient air through heat exchangers with the cool water,
>>>> but heat pumps would be more effective. I know old disused lift shafts are
>>>> also used for surface ventilation in many cases.
>>>>
>>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>>> the piston effect, and its stations were built with escalators, so there
>>>> aren't disused old lift shafts to re-use for surface ventilation.
>>>
>>> Although many of the stations on the line do have old lift shafts, and
>>> even purpose-built ventilation systems. Here's a really rather big one
>>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>>
>> Yes, that's a good example, but, self-evidently, more are needed.
>>
>> The size of that shaft illustrates how they're hard to fit into a busy
>> urban landscape.
>
> I think it's trendy to call it "the public realm" m'lud.
>
>> The ideal site is an abandoned surface station building (eg, when the
>> surface building is relocated when the original lifts are replaced by
>> escalators or an original station was simply closed), but the Victoria
>> line is too new to have any.
>
> https://goo.gl/maps/4oJmzZW2aNCmhCQJ6 perhaps?

What it's becoming:
<https://www.westonwilliamson.com/projects/euston-vent-shaft>

Ken <ken@birchanger.com> wrote:
> On Tue, 11 Oct 2022 21:25:44 +0100, Graeme Wall
> <rail@greywall.demon.co.uk> wrote:
>
>> On 11/10/2022 16:33, Muttley@dastardlyhq.com wrote:
>>> On Tue, 11 Oct 2022 09:16:15 -0000 (UTC)
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> It's a bit like the many people who think that the flash should be used
>>>> whenever pictures are taken in low light, even in large stadiums or
>>>> firework displays. Or, even worse, when taking pictures of objects behind
>>>> glass.
>>>
>>> I was at edinburgh castle many years ago and overhead a yank taking a picture
>>> of the city from the wall asking her friend if she should use the flash.
>>>
>>
>> The other side is trying to convince people to use flash when taking
>> photos of people with the sun behind them.
>
> I've tried. My phone camera decides that turning the flash ON should
> be ignored if it thinks it's light enough.
>

My phone's 'flash' is just an LED light. I don't think it would be a very
effective fill fash for a subject with strong back lighting. Of course, the
phone might decide to take an HDR stacked shot in such a case, which could
work quite well.

Roland Perry <roland@perry.co.uk> wrote:
> In message <ti60bg$1e9ta$1@dont-email.me>, at 09:11:12 on Wed, 12 Oct
> 2022, Tweed <usenet.tweed@gmail.com> remarked:
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> Roland Perry <roland@perry.co.uk> wrote:
>>>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>>>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>>> Ken <ken@birchanger.com> wrote:
>>>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>>
>>>>>>> Ken <ken@birchanger.com> wrote:
>>>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> What power are the fans, typically? Are we just considering
>>>>>>>>>> waste heat from the motors, or also the contribution of the
>>>>>>>>>> energy they impart to the moving air?
>>>>>>>>>
>>>>>>>>> Both, I think.
>>>>>>>>>
>>>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>>>> any useful work they do on the air increases its temperature.
>>>>>>>
>>>>>>> So, while the fans briefly cool the people walking past them,
>>>>>>> they actually warm up everyone else in the station, who just
>>>>>>> experiences the extra heat without benefiting from the breeze.
>>>>>>
>>>>>> That was my original point. I accept that the amount of extra energy
>>>>>> turned into heat is quite small, but I wonder if the fact that
>>>>>> electric fans actually heat a closed environment was known to TfL, and
>>>>>> they considered the transient relief to some passengers worth it; was
>>>>>> known but the optics were good; or did they not know?
>>>>>> The last of these isn't far fetched. I know of people who have fitted
>>>>>> ceiling fans to rooms that are left on all day because they believe
>>>>>> the rooms will be cooled.
>>>>>
>>>>> TfL is well aware of the issues and the physics,
>>>>
>>>> Of course they are. It's preposterous anyone thinks they aren't.
>>>>
>>>>> but is using these cheap,
>>>>> visible, noisy fans to show that it's doing *something * while it works on
>>>>> the much harder, more expensive long-term solutions.
>>>>>
>>>>> I'd like to hear more about the project to use the groundwater that's
>>>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>>>> to just blow warm ambient air through heat exchangers with the cool water,
>>>>> but heat pumps would be more effective. I know old disused lift shafts are
>>>>> also used for surface ventilation in many cases.
>>>>>
>>>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>>>> the piston effect, and its stations were built with escalators, so there
>>>>> aren't disused old lift shafts to re-use for surface ventilation.
>>>>
>>>> Although many of the stations on the line do have old lift shafts, and
>>>> even purpose-built ventilation systems. Here's a really rather big one
>>>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>>>
>>> Yes, that's a good example, but, self-evidently, more are needed.
>>>
>>> The size of that shaft illustrates how they're hard to fit into a busy
>>> urban landscape. The ideal site is an abandoned surface station building
>>> (eg, when the surface building is relocated when the original lifts are
>>> replaced by escalators or an original station was simply closed), but the
>>> Victoria line is too new to have any.
>>
>> But doesn’t the Victoria line share stations with many older lines? There’s
>> lots of scope to move air in great volumes inside the stations and up
>> through existing vent shafts. On my tour of Charing Cross (not Victoria I
>> know) there was shown all sorts of cross line vent tunnels, including the
>> out of service Jubilee spur. We had a wander down one of them.
>
> Ditto London Bridge, but the abandoned entrance building has now been
> redeveloped post-Shard. But the ventilation shaft has been re-born:
> https://goo.gl/maps/pxvkjM5XSpYpn1fs5

Another example from the same line: https://youtu.be/2RKqyN-4lUE

Recliner <recliner.usenet@gmail.com> wrote:
> Roland Perry <roland@perry.co.uk> wrote:
>> In message <ti60bg$1e9ta$1@dont-email.me>, at 09:11:12 on Wed, 12 Oct
>> 2022, Tweed <usenet.tweed@gmail.com> remarked:
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> Roland Perry <roland@perry.co.uk> wrote:
>>>>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>>>>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>>>> Ken <ken@birchanger.com> wrote:
>>>>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>>>
>>>>>>>> Ken <ken@birchanger.com> wrote:
>>>>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> What power are the fans, typically? Are we just considering
>>>>>>>>>>> waste heat from the motors, or also the contribution of the
>>>>>>>>>>> energy they impart to the moving air?
>>>>>>>>>>
>>>>>>>>>> Both, I think.
>>>>>>>>>>
>>>>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>>>>> any useful work they do on the air increases its temperature.
>>>>>>>>
>>>>>>>> So, while the fans briefly cool the people walking past them,
>>>>>>>> they actually warm up everyone else in the station, who just
>>>>>>>> experiences the extra heat without benefiting from the breeze.
>>>>>>>
>>>>>>> That was my original point. I accept that the amount of extra energy
>>>>>>> turned into heat is quite small, but I wonder if the fact that
>>>>>>> electric fans actually heat a closed environment was known to TfL, and
>>>>>>> they considered the transient relief to some passengers worth it; was
>>>>>>> known but the optics were good; or did they not know?
>>>>>>> The last of these isn't far fetched. I know of people who have fitted
>>>>>>> ceiling fans to rooms that are left on all day because they believe
>>>>>>> the rooms will be cooled.
>>>>>>
>>>>>> TfL is well aware of the issues and the physics,
>>>>>
>>>>> Of course they are. It's preposterous anyone thinks they aren't.
>>>>>
>>>>>> but is using these cheap,
>>>>>> visible, noisy fans to show that it's doing *something * while it works on
>>>>>> the much harder, more expensive long-term solutions.
>>>>>>
>>>>>> I'd like to hear more about the project to use the groundwater that's
>>>>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>>>>> to just blow warm ambient air through heat exchangers with the cool water,
>>>>>> but heat pumps would be more effective. I know old disused lift shafts are
>>>>>> also used for surface ventilation in many cases.
>>>>>>
>>>>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>>>>> the piston effect, and its stations were built with escalators, so there
>>>>>> aren't disused old lift shafts to re-use for surface ventilation.
>>>>>
>>>>> Although many of the stations on the line do have old lift shafts, and
>>>>> even purpose-built ventilation systems. Here's a really rather big one
>>>>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>>>>
>>>> Yes, that's a good example, but, self-evidently, more are needed.
>>>>
>>>> The size of that shaft illustrates how they're hard to fit into a busy
>>>> urban landscape. The ideal site is an abandoned surface station building
>>>> (eg, when the surface building is relocated when the original lifts are
>>>> replaced by escalators or an original station was simply closed), but the
>>>> Victoria line is too new to have any.
>>>
>>> But doesn’t the Victoria line share stations with many older lines? There’s
>>> lots of scope to move air in great volumes inside the stations and up
>>> through existing vent shafts. On my tour of Charing Cross (not Victoria I
>>> know) there was shown all sorts of cross line vent tunnels, including the
>>> out of service Jubilee spur. We had a wander down one of them.
>>
>> Ditto London Bridge, but the abandoned entrance building has now been
>> redeveloped post-Shard. But the ventilation shaft has been re-born:
>> https://goo.gl/maps/pxvkjM5XSpYpn1fs5
>
> Another example from the same line: https://youtu.be/2RKqyN-4lUE

Or a particularly creative example on the same line:
https://twitter.com/look_uplondon/status/1008597726408466432

Maybe there could be more disguised ventilation shafts like that, ideally
of politicians noted for their flowery, hot air speeches? Perhaps London's
second mayor of the modern era will one day be commemorated in that way?

On 12/10/2022 11:08, Recliner wrote:
> Ken <ken@birchanger.com> wrote:
>> On Tue, 11 Oct 2022 21:25:44 +0100, Graeme Wall
>> <rail@greywall.demon.co.uk> wrote:
>>
>>> On 11/10/2022 16:33, Muttley@dastardlyhq.com wrote:
>>>> On Tue, 11 Oct 2022 09:16:15 -0000 (UTC)
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> It's a bit like the many people who think that the flash should be used
>>>>> whenever pictures are taken in low light, even in large stadiums or
>>>>> firework displays. Or, even worse, when taking pictures of objects behind
>>>>> glass.
>>>>
>>>> I was at edinburgh castle many years ago and overhead a yank taking a picture
>>>> of the city from the wall asking her friend if she should use the flash.
>>>>
>>>
>>> The other side is trying to convince people to use flash when taking
>>> photos of people with the sun behind them.
>>
>> I've tried. My phone camera decides that turning the flash ON should
>> be ignored if it thinks it's light enough.
>>
>
> My phone's 'flash' is just an LED light. I don't think it would be a very
> effective fill fash for a subject with strong back lighting. Of course, the
> phone might decide to take an HDR stacked shot in such a case, which could
> work quite well.
>

Just had a play and I've the option of off, auto and on. The on works,
even in a bright environment.

--
Graeme Wall
This account not read.

On 12/10/2022 11:02, Recliner wrote:
> Roland Perry <roland@perry.co.uk> wrote:
>> In message <ti5scu$1dc0d$2@dont-email.me>, at 08:03:42 on Wed, 12 Oct
>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>> Roland Perry <roland@perry.co.uk> wrote:
>>>> In message <ti4432$14pkk$3@dont-email.me>, at 16:02:43 on Tue, 11 Oct
>>>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>>> Ken <ken@birchanger.com> wrote:
>>>>>> On Tue, 11 Oct 2022 09:10:21 -0000 (UTC), Recliner
>>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>>
>>>>>>> Ken <ken@birchanger.com> wrote:
>>>>>>>> On Mon, 10 Oct 2022 12:44:19 +0100, Roland Perry <roland@perry.uk>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> In message <ti0svo$pjqu$1@dont-email.me>, at 10:43:04 on Mon, 10 Oct
>>>>>>>>> 2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> What power are the fans, typically? Are we just considering the
>>>>>>>>>> waste heat
>>>>>>>>>> from the motors, or also the contribution of the energy they
>>>>>>>>>> impart to the
>>>>>>>>>> moving air?
>>>>>>>>>
>>>>>>>>> Both, I think.
>>>>>>>>>
>>>>>>>> Of course. It doesn't matter how efficient or inefficient the fans
>>>>>>>> are. They produce waste heat via resistive heating and friction and
>>>>>>>> any useful work they do on the air increases its temperature.
>>>>>>>>
>>>>>>>
>>>>>>> So, while the fans briefly cool the people walking past them, they
>>>>>>> actually
>>>>>>> warm up everyone else in the station, who just experiences the extra heat
>>>>>>> without benefiting from the breeze.
>>>>>>
>>>>>> That was my original point. I accept that the amount of extra energy
>>>>>> turned into heat is quite small, but I wonder if the fact that
>>>>>> electric fans actually heat a closed environment was known to TfL, and
>>>>>> they considered the transient relief to some passengers worth it; was
>>>>>> known but the optics were good; or did they not know?
>>>>>> The last of these isn't far fetched. I know of people who have fitted
>>>>>> ceiling fans to rooms that are left on all day because they believe
>>>>>> the rooms will be cooled.
>>>>>
>>>>> TfL is well aware of the issues and the physics,
>>>>
>>>> Of course they are. It's preposterous anyone thinks they aren't.
>>>>
>>>>> but is using these cheap,
>>>>> visible, noisy fans to show that it's doing *something * while it works on
>>>>> the much harder, more expensive long-term solutions.
>>>>>
>>>>> I'd like to hear more about the project to use the groundwater that's
>>>>> constantly pumped out of the system as a heat sink. The cheap approach is
>>>>> to just blow warm ambient air through heat exchangers with the cool water,
>>>>> but heat pumps would be more effective. I know old disused lift shafts are
>>>>> also used for surface ventilation in many cases.
>>>>>
>>>>> The Victoria line has particular issues, as it doesn't get the benefit of
>>>>> the piston effect, and its stations were built with escalators, so there
>>>>> aren't disused old lift shafts to re-use for surface ventilation.
>>>>
>>>> Although many of the stations on the line do have old lift shafts, and
>>>> even purpose-built ventilation systems. Here's a really rather big one
>>>> at Kings Cross: https://goo.gl/maps/fXGDvhB3SRqKfmar6
>>>
>>> Yes, that's a good example, but, self-evidently, more are needed.
>>>
>>> The size of that shaft illustrates how they're hard to fit into a busy
>>> urban landscape.
>>
>> I think it's trendy to call it "the public realm" m'lud.
>>
>>> The ideal site is an abandoned surface station building (eg, when the
>>> surface building is relocated when the original lifts are replaced by
>>> escalators or an original station was simply closed), but the Victoria
>>> line is too new to have any.
>>
>> https://goo.gl/maps/4oJmzZW2aNCmhCQJ6 perhaps?
>
> What it's becoming:
> <https://www.westonwilliamson.com/projects/euston-vent-shaft>
>

But, by God, that is UGLY!

--
Colin