I'm not sure what your question is...
I wasn't saying it's "worth it" to hook up the hot water...
I agree with you, the heat of vaporization has to come from somehwere
either way.., either all from the furnace or the 10% fom the hot water
heater and 90% from the furnace...... so it's 6 of one half a dozen of
And if the hot water heater is electric and the furnace is something
cheaper, then it's probably a looser to hook up the hot water.
On Feb 9, 11:25 pm, firstname.lastname@example.org wrote:
Nor is anyone else.
But Bubba doesn't say that at all. He says the energy is a free ride
if all comes from the furnace, since the furnace is running anyway.
I agree with you Mark, that energy wise, it's close to a wash.
Either the energy to heat the water comes partially from the water
heater or all from the furnace. But either way, assuming the same
fuel, the energy cost is close, because both have efficiencies in the
I would agree with that.
In fact, I think we agree on everything, except exactly how much more
water evaporates in the humidifier using hot. You think it's not
significant, but I and Aprilaire, think it is. I understand your
point about how much heat is necessary to change the phase of water
from liquid to vapor and how that heat is much larger than the heat to
raise the water's temp. It's a very good point. However, my point
is that evaporation using an air flow device like the humidifier is
not as simple as just a phase change. It's a complex process
involving mass transfer by the air too, which is a complex
problem. To get those water molecules off the panel, all that has
to happen is to have the fastest moving ones at the surface escape the
surface tension of the water. The more energy those surface
molecules have, the more likely they will be caught up and swept away
by the fast moving air at the boundary layer..
Let me ask you this question. Let's say water enters the top of a
rectangular distribution panel in the humidifier, which is about a
foot long, and flows vertically down via gravity Let's say it's at
130 deg when it enters. Bubba claims the water has completely
cooled before it's even reached the top of the distribution tray,
which is to say it's cooled in just 1/2" inch while still in a pencil
size stream. I'd say the temp drops more slowly, and the water temp
could be higher using hot water for a good ways down the panel.
Maybe 1/2 way down. So you have a temp gradient going down the
panel from 130 to whatever the final stead-state temp is going to be,
let's say for discussion that it's 90 deg.
In the case of using cold water, you have the opposite. Water is
entering at 40 deg and going up to 90 deg for some portion of the
panel. Eventually, it rises to the same steady state temp, of 90
deg. So, in once case you have water at an avg temp of 110 for a good
portion of the panel. In the other case, you have water at 65 deg
for a good portion of the panel. I think that portion of the panel is
large enough that this temp difference makes a significant difference
in how much water evaporates. In the case of using the 130 deg
water, how far down the panel do you think the water goes before it
reaches the steady state temp?
Also, regarding evaporation rates and temperature, it's well known
that water evaporation rates over the tropical oceans are
significantly higher than they are over cooler oceans. If water temp
has only a negligible effect on rates of evaporation, how can this
be? The ocean temps vary by far less than the 130 deg vs 40 deg we
have with the humidifier example.
OK we agree that you need a certain amount of heat to evaporate say 1
gallon of water and that heat has to come from either the furnace or
the hot water heater... ok..
You think it's not
I agree that the hotter the water IS in the panal, the faster it
I think we disagree on this part.. I think (similar as Bubba) that if
you feed hot water, it will cool off very quickly as it starts to
evaporate.. in other words the initial heat energy in the hot feed
water will be used up fast since it's only 10% of the total
needed... and after that inital 10% energy is used up, the water
will be the same temp (and evaporate at the same rate) as it would if
cold water fed in at the top. I think your estimate that the water
will take 1/2 the panel to cool is wrong becasue you have to remember
that evaporating water sucks up a very large amount of heat. So 8000
BTU are needed to evaporate a gallon. And the hot water supplies an
So I thik we agree that the water temperature DOES indicate how fast
the water is evaporating, but we don't agree how hot the water will be
in the panel. This make the experiment easier if you want to do it.
You just have to determine the water temp in the panel... I think it
will be nearly the same regardless of how hot the feed water is. The
temp of the water in the tray will be determined by the furnace air
temp and how fast the air is blowing etc. As you said it is
complex... but from an energy point of view.... we know you need a
total of 8000 BTU to evaporate a gallon. The feed water being hot to
start with supplies only an extra 800 BTU. The remaining 7200 BTU
still has to come from the furnace.
I also agree it is complex, things like the size of the spray droplets
and the air and all kinds of things effect how fast the water will
evaporate. But in the end 8000 BTU will be consumed per gallon and I
think an extra 800 BTU head start still amounts to only 10%
If you were blowing air at 500 miles per hour, yes a lot more water
would evaporate a lot faster but the 800 BTU from the hot water feed
would just get used up that much more quickly...it's still 10% of the
total per gallon..
Think about the clothes dryer analogy. You put in clothes that are
wet. In one case the clothes are wet with hot water. In another
they are wet with cold water. After a short time, the hot water
clothes are going to be nearly the same temp as the cold water
clothes. And we agree that the temp effects the rate of evap so if
the temp is nearly the same, the rate of evap is nearly the same.
I think the thing you are stuck on is the hot water is heated only
once. If you could put the hot water heater ELEMENT in the humidifer
so you could add lots and lots of BTU all the time, as the water
evaporated and used them up you could replace them from the
element ...then YES I would agree with you it woould make a big
difference. But that's not the case we have here. The water is
heated only one shot and therefore it can carry about 800 BTU per
gallon and that is only about 10% of what is needed to evaporate it..
And I want to thank you for having a civil discussion without name
Many folks on newsgroups can't seem to do that.
On Tue, 10 Feb 2009 15:21:06 -0800 (PST), email@example.com wrote:
And I respect your civil discussion as some of us (me) have a little
bit harder time with that but..................
WOW! If you look this thread over and see how long its been going and
for someone thats in the business (like me) that has installed
hundreds and hundreds of humidifiers of all types over the years and
purposely did the test I have described over and over to trader and he
refuses to do it but just keeps guessing and spitting out wrong info
it just gets a little overbearing for me.
Im not one to let wrong info go by the wayside when Ive actually done
it for myself.
Anyways, thats my story and Im sticking to it.
On Tue, 10 Feb 2009 06:35:42 -0800 (PST), firstname.lastname@example.org wrote:
Yours is just a block-head problem though, trader.
Hmmm, trader. For someone that claims to not understand me, now all of
a sudden you want to quote me. C'mon. Make up your mind.
There you go again. Your comprehension level seems to be dropping like
a rock off a cliff, trader. NEVER, did I say it was free. More concret
for that block-head of yours?
I still say you are wrong trader. Why make the water heater come on
and heat the tank back up when the furnace already has to run? Again,
Im not saying its free but more practical and more efficient.
Yet you refuse to test the results for over a month or more now but
instead just keep flapping your yapper, trader. Prove me wrong.
Just for the heck of it, do you understand the venturi effect? What do
you think happens to that water right where it reaches the orifice?
Its shot into that tube where it loses even more temperature. Again,
try it and test the temps and measure the water coming out of the
Oh forget it. You never will.
No trader you dipwad. You're making up shit again. I never said it
cooled complety. I say that by the time it has reached the
distribution tray and starts to drop through, it has cooled
considerably. Then as soon as the air hits it near the top of the pad
the temp is pretty much dropped to room temperature.
Got it now? Do I need to draw you a picture or do you need another bag
of concrete for your block-head?
Maybe, sort of, could have, I think, could be, etc. etc. etc. Maybe
monkeys will fly out of your ass too but I really doubt it.
discussion? yeah, thats just great trader. Anyone can make up shit. I
seem to know someone else in here that flips numbers out like that. Is
that how we need to classify you know?
Oh my trader. How about you test out that theory instead of just
flappin your jaws about it?
Hey trader. How about we just stick with the humidifier for now and
leave the temperatures of the ocean alone. I think this humidifier
experiment is way over your head as it is.
Maybe you and Al Gore can have a discussion about the hole in the
On Mon, 9 Feb 2009 20:25:48 -0800 (PST), email@example.com wrote:
I guess I wasnt really asking a question even though I started the
sentence of say "Im just asking..."
I think really I was just stating what I see happening.
What Id really like to see is someone like Aprilaire show me just how
much water is being evaporated using hot water.
Actually Im meeting with my Aprilaire rep on Friday for breakfast.
I'll see if he can get one of the higher ups at Aprilaire to get me
some kind of facts or written info on the use of hot water with
Yeah, maybe a better explaination would be using an oil fired hot
water heater to heat water as opposed to using a gas furnace to heat
the air and transfer that heat to the water. I know I didnt bring up
that scenario but trader acts like it doesnt matter how you do it. One
way or the other it costs almost the same. I disagree. Thats why I
brought up the jet engine heating the cup and a small torch (or
whatever I said). Maybe just maybe that explaination makes it a little
clearer? I doubt it for someone here though.
I think you and Trader actually agree in principal that using hot
water makes at least some small difference. Trader thinks it makes a
big diff and you (and I) think it makes only a little diff. My rough
cut math says its about 10% and you would never notice that without
some kind of measurement.
It would be interesting to see if the rep from Aprilare gives you a
I also think we all agree thats it's a matter of the water temperature
inside the humdifier.., if Trader can agree (or measure) that the
water temp is about the same, then we can all go have a beer.
Your science gets worse by the minute. Whatever heat it takes it has
to come from somewhere. If the heat is provided by the furnace then
there is that much less heat available to raise the temp of the air.
It's heating water instead of air. If it's provided by the water
heater, then the energy comes from the gas burned in the water
heater. We already went through that and you compared it to heating
a cup of water with a propane torch vs the exhause from a jet
engine. Which of course is ludicrous, because those two are nowhere
near as efficient methods, so of course there is a huge difference.
In the case under discussion here, heating water whether in the water
heater or via the furnace is in the same ballpark in efficiency.
Who cares whether it's 120 or 150. The obvious point is that it's a
lot higher than 40 or 50 deg deg cold water.
On Tue, 10 Feb 2009 05:46:15 -0800 (PST), firstname.lastname@example.org wrote:
Now you're making sense. :-)
No, actually your reasoning gets worse and worse. It comes from having
a head made of concrete and believing everything someone writes on a
piece of paper and you read it.
Tell me, you dont believe everything you read on the internet, do you?
Yes, we did go through this and you act like providing humidification
by either heating water with a water heater or providing it with a
furnace is the same. Thats just plain ignorant of you. There are
better, more effective, efficient ways to do most everything. You
happen to be wrong but cant live with yourself knowing you screwed up.
Oh, so now heating water to 120 degrees cost the same as heating it to
150 degrees. Must be that universe you were talking about that you
just landed in.
I had a steam generator installed on a new heat pump/electric zone and
the moisture ruined the coils, enclosure,etc. Currently have an April
Aire (and of course a new air handler) which drains excess water to a
summer condensate tank with a float switch operated pump which pumps the
drain water up about eight feet through a loop and a check valve into a
grey water house drain system. I have not found any of them to be great
in this house which is rather large.
replying to borealbushman, Steve's Heating Gaylord Michigan wrote:
I have been in Residential HVAC for 30yrs, Most of them servicing
The output of any humidifier is based on having a minimum temp of air
going across the pad/panel etc , the warmer the air, the more water it can hold,
which equals the more moisture it will evaporate in a single pass. Geothermal
units operate at lower outlet temps than gas fired equipment, therefore you
need to select a humidifier which been manufactured to add more humidity at
these lower temps.....there are many ways in which they operate, (steam, fan
power assist, direct mist etc...) All of these have specific operating
conditions, such as existing duct layouts, (to prevent water accumulating on
duct surfaces etc)..... so be sure to hire a company with experience with
these special humidifiers, because if the requirements for the installation of
these units aren't met, at the very least, they may cause damage to the
equipment. Uncontrolled water contact can cause indoor mold issues.
Always hire a licensed/insured contractor.........always.
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