On Tue, 21 Jan 2014 04:48:42 -0800 (PST), "
wrote:

On Monday, January 20, 2014 2:14:33 PM UTC-5, micky wrote:
On Mon, 20 Jan 2014 07:35:58 -0500, Stormin Mormon

wrote:



Weather forecast for this week is windy, gusts

up to 45 MPH, and also temps near zero F.



Will the wind chill make it more likely for me

to freeze pipes? Compared to still air?



If your pipes don't perspire or leak, if they're not wet on the outside,

wind chill is not a factor.

BS. Following that theory, a car radiator is transfering just
as much heat with no air moving through it as it is with a high
volume of air moving through it.


It doesn't exist for pipes that are not

wet on the outside.

Wrong. If you have a brick that is 100F and you put it
outside when it's 50F, does it cool off faster with or without
a fan blowing on it?



Even though plenty of people talk like it does.



It doesn't exist for cars, either, unless they are wet on the outside.

Not "were wet" but "are wet".



Then feel free to block the airflow to your radiator. It will
still transfer the same amount of heat, right?



It exists for people, who perspire, a little bit everywhere I think.

The wind blows across the wet skin, even so slightly wet that it doesn't

feel wet, and the water draws heat from the skin as it evaporates.

You completely ignore the heat removed by *convection*. It doesn't
have to be wet. If it is wet, then yes that increases the heat
transfer.



The quantity of heat needed to make water evaporate, the heat of

vaporization, is the same as the heat required to raise the temperature

of the same amount of water by 15 or 20 degrees, iirc. It's the same

amount of heat needed by water about to boil on a stove, to go from

water to water vapor, although I guess one cannot tell by looking how

much heat that is.



Which has nothing to do with the situation at hand.



I don't know about other animals. Dogs pant, but do they in very cold

weather? Probably not,

And people don't sweat on their exposed skin when it's 15F either.




and I've never heard of a dog's tongue freezing

because of wind chill. They probably keep their tongues in their

mouths.





When it's near zero F, and winds of 45 MPH,



The wind doesn't matter, but the 0F does.



Of course the wind matters. You think it takes just as much
energy to heat a house when it 0 with a 45 MPH wind and without?
Good grief.


I've decided that your saying Good grief is reason enough not to reply.

You like insults better than a real discussion, and I don't.





should I leave a faucet dripping?



If it is actually zero where the pipe is, yes.



Just if it's zero? Just a drip? Good grief.




LIke under the trailer maybe, where it's not heated? What do other

people with trailers do? If you live in a trailer park, you'd find more

people who know abou tthis there than you willl here. Or at least they

should know what they do and what happens to their pipes when they do

it. Even if you don't live in one, go visit one and ask them.

Yes, great idea. I live in a house and I should go survey
folks who live in a trailer. Good grief.


Isn't

there usually a manager. He should know what to do.



Would it be better to leave a hot drip, or a

cold drip?



Whichever pipe is exposed to the very cold temperature. Both of them,

if that is the case.



And I'll bet if the pipes are really exposed to the very cold, eg 0F
number you cited, that they will freeze with just a drip anyway.
The lower the temp, the more exposed, the more water you need flowing.




What was the agreement, last time I asked? I think

we all on the list agreed about our answers.



I vaguely remember someone called me an idiot.



I can see why.

On Wednesday, January 22, 2014 7:00:08 AM UTC-5, micky wrote:
On Tue, 21 Jan 2014 04:48:42 -0800 (PST), "

wrote:



On Monday, January 20, 2014 2:14:33 PM UTC-5, micky wrote:

On Mon, 20 Jan 2014 07:35:58 -0500, Stormin Mormon



wrote:







Weather forecast for this week is windy, gusts



up to 45 MPH, and also temps near zero F.







Will the wind chill make it more likely for me



to freeze pipes? Compared to still air?







If your pipes don't perspire or leak, if they're not wet on the outside,



wind chill is not a factor.



BS. Following that theory, a car radiator is transfering just

as much heat with no air moving through it as it is with a high

volume of air moving through it.





It doesn't exist for pipes that are not



wet on the outside.



Wrong. If you have a brick that is 100F and you put it

outside when it's 50F, does it cool off faster with or without

a fan blowing on it?







Even though plenty of people talk like it does.







It doesn't exist for cars, either, unless they are wet on the outside.



Not "were wet" but "are wet".







Then feel free to block the airflow to your radiator. It will

still transfer the same amount of heat, right?







It exists for people, who perspire, a little bit everywhere I think.



The wind blows across the wet skin, even so slightly wet that it doesn't



feel wet, and the water draws heat from the skin as it evaporates.



You completely ignore the heat removed by *convection*. It doesn't

have to be wet. If it is wet, then yes that increases the heat

transfer.







The quantity of heat needed to make water evaporate, the heat of



vaporization, is the same as the heat required to raise the temperature



of the same amount of water by 15 or 20 degrees, iirc. It's the same



amount of heat needed by water about to boil on a stove, to go from



water to water vapor, although I guess one cannot tell by looking how



much heat that is.







Which has nothing to do with the situation at hand.







I don't know about other animals. Dogs pant, but do they in very cold



weather? Probably not,



And people don't sweat on their exposed skin when it's 15F either.









and I've never heard of a dog's tongue freezing



because of wind chill. They probably keep their tongues in their



mouths.











When it's near zero F, and winds of 45 MPH,







The wind doesn't matter, but the 0F does.







Of course the wind matters. You think it takes just as much

energy to heat a house when it 0 with a 45 MPH wind and without?

Good grief.





I've decided that your saying Good grief is reason enough not to reply.


Yeah, good idea. Focus on that instead of the fact that you
have the science wrong.






You like insults better than a real discussion, and I don't.



Good grief is an insult? What you don't like is being told
that you're wrong and having it explained to you.
Otherwise, you'd be discussing and replying
to the two examples I just gave you. Wind removes heat from
exposed skin via convection, just like it does from any object
that is above ambient temperature. Evaporation is not necessary.
The cooling of exposed skin
is *not* driven primarily by evaporation, unless you're sweating
when it's 15F out. Seems hundreds of millions of years of
evolution has figured that out. It's driven by convection,
just like using *moving* air through a car radiator works.
And BTW, I figured the good grief was appropriate because
I've clearly explained this to you ten times now, here and
in the other thread. CL told you the same thing.

On Wed, 22 Jan 2014 05:05:32 -0800 (PST), "
wrote:

Snip

Yeah, good idea. Focus on that instead of the fact that you
have the science wrong.

One would think that with a growing number of voices in opposition to
your "science" that there may be a chance you have it wrong.

wrote in message news:2f29c90e-9f4c-4c4b-bb95-

stuff snipped

It pains me to do this, but Trader's right about this. The concept of
higher air flow resulting in greater heat transfer is the guiding principle
behind the calculation of the wind chill index. Any restrictions placed on
what wind chill means are irrespective of the science behind its
calculation.

The clearest example I can think of heat transfer via moving air is like
Trader's car fan example. Faster computer CPU speeds (and power
consumption) forced the industry to mount fans atop their CPUs. They did
that because passive cooling, even from massive heat sinks, caused the
faster CPUs to burn up. Moving air removes heat more quickly than still
air, whether it's a CPU, a pipe or a human being. Hair dryers would
incinerate themselves without a fan to transfer heat from the heating coils.

Wind removes heat from exposed skin via convection, just like it does
from any object
that is above ambient temperature. Evaporation is not necessary.

Correct, but evaporation does play a small role, as do many other things.
Ask yourself whether you'd rather be stranded outside at 0F with a wet
jacket or a dry one. (-: (And yes, I know that wet clothes transfer heat
more rapidly than dry ones and insulation loses R-value when wet.)

Evaporative cooling is more important to windchill's fraternal twin, the
heat index. That's when sweating in a humid environment does not cool the
skin well and so 100F degrees in Atlanta or DC can feel like 110F in the
desert. It seems that the two concepts got slightly mashed up in this
thread. There's fascinating reading at:

http://en.wikipedia.org/wiki/Wind_chill

that describes a number of controversies associated with calculating
wind-chill, windchill, wind chill, wind chill index or the wind chill factor
(the fact that no one can agree what to call it speaks volumes about its
controversial nature).

The method for calculating wind chill has been controversial because
experts disagree on whether it should be based on whole body cooling either
while naked or while wearing appropriate clothing, or if it should be based
instead on local cooling of the most exposed skin, such as the face. The
internal thermal resistance is also a point of contention. It varies widely
from person to person. Had the average value for the subjects been used,
calculated WCET's would be a few degrees more severe.
The 2001 WCET is a steady state calculation (except for the time to
frostbite estimates).[13] There are significant time-dependent aspects to
wind chill because cooling is most rapid at the start of any exposure, when
the skin is still warm.

While there can be some defintional arguments about whether wind chill can
be used when discussing non-human objects, there's no argument that air
moving over something will transfer heat faster than no air movement.

Generally, wind chill cannot lower the temperature of something lower than
the ambient temperature *unless* there's enough liquid evaporating (think
Great Lakes) to account for a substantial temperature drop. If my wife
hadn't declared a moratorium on freezer-related experiments, I would even
try hooking up some thermocouples to both wet and dry pipe sections in the
freezer to see whether a wet pipe had a noticeable temperature difference
due to evaporation. Maybe some bachelor will do "the science" for us. (-:

Definitional purists would be correct in saying that wind chill does not
apply to inanimate objects but the scientific formula for computing it still
remains in place and that says the faster the wind, the greater the heat
transfer. For humans, pipes, dogs and CPU's alike.

The Aussies have created an AAT (Aussie Apparent Temperature) just to
confuse things further.

http://www.weather-watch.com/smf/ind...?topic=52051.0


--
Bobby G.

Stormin Mormon wrote:
Weather forecast for this week is windy, gusts
up to 45 MPH, and also temps near zero F.

Will the wind chill make it more likely for me
to freeze pipes? Compared to still air?

When it's near zero F, and winds of 45 MPH,
should I leave a faucet dripping?

Would it be better to leave a hot drip, or a
cold drip?

What was the agreement, last time I asked? I think
we all on the list agreed about our answers.

I vaguely remember someone called me an idiot.


I was doing some more sealing cracks at my old house.
The wind gets into them.

Greg

On 1/21/2014 12:19 AM, gregz wrote:


I was doing some more sealing cracks at my old house.
The wind gets into them.

Greg


Caulk is good, and that "great Stuff" foam is also good.
I figure any where cold air blows in, hot air has to be
blowing out the other side.

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..