On Jan 24, 4:10*pm, bob haller wrote:
On Jan 24, 8:25*am, "
wrote:
On Jan 24, 3:10*am, harry wrote:
On Jan 23, 4:02*pm, bob haller wrote:
On Jan 23, 9:50*am, ChrisCoaster wrote:
On Jan 22, 2:38*pm, "
wrote:
On Jan 22, 2:07*pm, Vic Smith wrote:
On Sun, 22 Jan 2012 10:12:31 -0800 (PST), "
wrote:
How useful it is or isn't depends on what the application
needs. *As I recall we were discussing how to get the most
heat out of a radiator or heat exchanger. *And you do that
by moving the MOST airflow possible past it until you reach
the point where the air and water exiting are at the same
temperature. *Then you have extracted all the heat possible
and further increases in airflow don't produce any further
increase in heat. * It's really very simple physics and it
works the same for the heat exchanger, a home radiator, a car
radiator, etc.
All your physics is correct.
What's that got to do with harry?
Harry's physics is totally wrong, that's the problem.
He doesn't understand the difference between
heat and temperature, as evidenced by nonsense
such as this:
" There is only so much radiation falling on the solar heater. If
you
want to get the maximum energy out of it you pass the water through it
as slow as possible to achieve the highest temperature.
So, he thinks you get more heat out of the solar array
by passing a pint of water through it and getting a pint
of say 160F water instead of 10 gallons of 100F water.
He continously confuses temperature with heat and
doesn't account for MASS in anything.
I once mentioned I cranked down the gas supply on my old boiler
because it was throwing massive heat up the chimney.
The burners were obviously overpowering the heat exchanger
capacity to absorb heat.
It was an old thing designed when NG was dirt cheap.
Of course I adjusted air to the flame and had good flame, and of
course cycle-on increased.
But my gas usage decreased.
harry still didn't like that.
Funny thing in all this is that he has the nerve to
constantly carp about the US and claim that we
don't have efficient furnaces, boilers, etc. *Yet
it's clear he doesn't even understand high school
physics. *In fact, for most of what I've tried to
explain to him, just practical everyday experience
is all you need.
I always wanted a small fan across my radiator fins when I had hot
water heat, to aid convection. *Never did it though.
Too much work, and they worked well enough.
--Vic
Nah, couldn't be. *According to harry, you get the most
heat when the air from that radiator is hottest. *You
should put a box around it.- Hide quoted text -
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________________________
So pretty much what I'm getting here is that #1 - Still water runs
cold(keep water moving) and #2 - Heating will be more efficient if I
place electric fans to blow across radiators where I need more heat,
correct?
Ver-r-r-y interesting...http://nakedphilly.com/wp-content/up...resting-mo...-
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over cooling the water temp will cause cool exhaust air from fans
making you feel cooler- Hide quoted text -
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You can't explain that to dead meat/the troll.- Hide quoted text -
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Excuse me, the entire discussion
we were having was about the physics of heat transfer,
NOT about how people perceive heat. * Sure, 200 CFM
of air coming out of a register that is just a couple degrees above
room temperature can feel cooler than 10 CFM of air
*that is 20 deg hotter than room temperature. *That has
nothing to with which one puts more heat into the house.
In other words, you're once again confusing heat with
temperature.- Hide quoted text -
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well ultimately what matters more?
the most heat is extracted buy we feel like were freezing?
or a little less heat transfer but were warm and toasty feeling?- Hide quoted text -
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That's an entirely different subject. The issue was
how you extract the most heat out of a water to air heat
exchanger, ie simple physics. You do that by moving
the most air possible past it, a fact which harry
can't grasp.
I agree that you might want the air to be hotter.
In that case you move less air pass it, getting
warmer air, but you are then getting less than
the maximum possible heat out the heat
exchanger. The issue started over an
attempt to use solar panels that are already
heating a hot water tank. Now you have
panels that are likely sized to a water heater
and already doing duty heating that. So, there
probably isn't a lot of spare heat available.
The issue becomes if you're not extracting
the max heat possible from the heat exchanger,
or close to it, you may not be getting enough
heat out of it for it to be worth it at all.
That was why i said you might as well just
put all the furnace airflow through it since
that would give you the most heat going into
the house possible. Which, of course, harry
vehemently disagreed with, the physics be
damned.