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Home > Archive > Alternative Power sources > July 2007 > Two story hot water tank ?
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Two story hot water tank ?
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| I was wondering,... my natural gas HWT is in the basement, would
it be cost effective to install another one on the first floor and vent
the lower tank through the floor to the second tank to prewarm or heat
the water in the second tank? Would a power vent be needed to exhaust
the fumes? The second floor tank would not have a burner but only be
used to capture the wasted heat now going out the vent. Plumbing would
be changed to go to the top tank first then the prewarmed water would go
to the HWT.
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| hallerb@aol.com 2007-07-05, 9:25 am |
| On Jul 4, 12:48?pm, Moe <BubbleleL...@Fat.City> wrote:
> I was wondering,... my natural gas HWT is in the basement, would
> it be cost effective to install another one on the first floor and vent
> the lower tank through the floor to the second tank to prewarm or heat
> the water in the second tank? Would a power vent be needed to exhaust
> the fumes? The second floor tank would not have a burner but only be
> used to capture the wasted heat now going out the vent. Plumbing would
> be changed to go to the top tank first then the prewarmed water would go
> to the HWT.
could create a real safety hazard, the exhaust gasses must be hot
enough to leave the building, your idea would cool them so much and
create a carbon monoxide hazard.
sorry for the bad news but good thinking out of the box.
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| daestrom 2007-07-06, 9:25 am |
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"Moe" <BubbleleLand@Fat.City> wrote in message
news:ibQii.49762$tL1.8523@newsfe22.lga...
> I was wondering,... my natural gas HWT is in the basement, would it
> be cost effective to install another one on the first floor and vent the
> lower tank through the floor to the second tank to prewarm or heat the
> water in the second tank? Would a power vent be needed to exhaust the
> fumes? The second floor tank would not have a burner but only be used to
> capture the wasted heat now going out the vent. Plumbing would be
> changed to go to the top tank first then the prewarmed water would go to
> the HWT.
If your basement heater is 'natural draft', then the gasses have to be hot
enough to create a draft up the flue. Cooling them too far may cause
problems when the wind blows wrong or the house is all 'sealed-up' for bad
weather.
If your basement heater is already a 'power vent' type, I think you'll find
the air dilution is so much that the vent outlet is pretty cool already and
you won't recover much more.
Now, if you 'natural draft' from basement to first floor, the gasses will be
hot when they reach the first floor (assuming you properly insulate the pipe
(don't forget fire-stop spacing around the flue). Then 'power vent' from
the first-floor unit to outside to maintain the draft, it might work. But
I'd be sure to have a working CO monitor, just in case.
daestrom
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| daestrom wrote:
>
> "Moe" <BubbleleLand@Fat.City> wrote in message
> news:ibQii.49762$tL1.8523@newsfe22.lga...
>
> If your basement heater is 'natural draft', then the gasses have to be
> hot enough to create a draft up the flue. Cooling them too far may
> cause problems when the wind blows wrong or the house is all 'sealed-up'
> for bad weather.
>
> If your basement heater is already a 'power vent' type, I think you'll
> find the air dilution is so much that the vent outlet is pretty cool
> already and you won't recover much more.
>
> Now, if you 'natural draft' from basement to first floor, the gasses
> will be hot when they reach the first floor (assuming you properly
> insulate the pipe (don't forget fire-stop spacing around the flue).
> Then 'power vent' from the first-floor unit to outside to maintain the
> draft, it might work. But I'd be sure to have a working CO monitor,
> just in case.
>
> daestrom
>
Guys, I unhook the vent to the HWT in winter and let it heat under
the house, keeps the pipes from freezing and we have low humidity so the
extra vapor doesn't hurt, at least not in my case. I've got a couple
of CO detectors with digital read outs and alarms and they have never
ever ever registered any CO from natural gas burning. I also heat the
house with a unvented radiant wall heater and unvented central heat.
But put a cigarette under the CO detector and watch it ! 250 PPM shows
up very quickly and the alarms work. Yea I know I'll wake up dead
someday but it's worked fine for the last 20 plus years. There is
plenty of heat coming out the top of the HWT to create a draft through
another tank and in my case it would then vent into the house any way.
Interesting to watch the CO detector in the garage, start the car and
it goes up then goes down as the catalytic converter fires, about 50
ppm CO is all it will show after and hour with the door closed. Start a
lawnmower, weed trimmer, chainsaw generator etc. in the garage with the
door closed and it can easily peg it at 999 in a short time. You guys
can vent and waste 20 to 30% of the heat to the outside, I'll use it
one way or the other.
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| so begins natural selection...
This is so dumb. I guess all those smart engineers and firemen just must
be wrong.
"Waste" heat or die...let me think about that.
Seriously, if your house is leaky enough, you might just survive. And
how are the CO2 measurements? Or NOx? Not all combustion is complete all
the time.
In article <qtOji.1290$K73.1255@newsfe13.lga>,
Moe <BubbleleLand@Fat.City> wrote:
> daestrom wrote:
> Guys, I unhook the vent to the HWT in winter and let it heat under
> the house, keeps the pipes from freezing and we have low humidity so the
> extra vapor doesn't hurt, at least not in my case. I've got a couple
> of CO detectors with digital read outs and alarms and they have never
> ever ever registered any CO from natural gas burning. I also heat the
> house with a unvented radiant wall heater and unvented central heat.
> But put a cigarette under the CO detector and watch it ! 250 PPM shows
> up very quickly and the alarms work. Yea I know I'll wake up dead
> someday but it's worked fine for the last 20 plus years. There is
> plenty of heat coming out the top of the HWT to create a draft through
> another tank and in my case it would then vent into the house any way.
> Interesting to watch the CO detector in the garage, start the car and
> it goes up then goes down as the catalytic converter fires, about 50
> ppm CO is all it will show after and hour with the door closed. Start a
> lawnmower, weed trimmer, chainsaw generator etc. in the garage with the
> door closed and it can easily peg it at 999 in a short time. You guys
> can vent and waste 20 to 30% of the heat to the outside, I'll use it
> one way or the other.
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| lnh wrote:[color=darkred]
> so begins natural selection...
>
> This is so dumb. I guess all those smart engineers and firemen just must
> be wrong.
>
> "Waste" heat or die...let me think about that.
>
> Seriously, if your house is leaky enough, you might just survive. And
> how are the CO2 measurements? Or NOx? Not all combustion is complete all
> the time.
>
> In article <qtOji.1290$K73.1255@newsfe13.lga>,
> Moe <BubbleleLand@Fat.City> wrote:
>
CO2? I drank a soda and was exposed to more CO2 then the space
heaters and HWT will put out in a year. There was quite an argument
about DC vs alternating current in the early 1900's because of the risk
of high voltage AC current, the risk was determined to be worth the
reward. I consider saving 30% on my natural gas bill each month well
worth the risk. If burning natural gas was so dangerous everyone with
a natural gas cook stove who ever warmed a can of beans would be dead by
now. People don't understand risk, fear, emotions etc. This is so
typical of the average American, drive a SUV because it is safer, but
send troops to Iraq to get the needed crude supply for the SUV. How
many people died in the USA last year due to unvented natural gas
appliances and space heating? How many died in Iraq? How many people
were electrocuted with AC current? I spend around 1000 a year on
natural gas, it would be 1300 a year if I vented the stoves and HWT,
take 300 times 20 years, that's 6K in expendable income. You can play
with the numbers, invest it, collect interest on it, pay for a funeral
with it, buy health insurance with it? Whatever,
None are so blind as those that will not see.
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| Hmmm...... You start out asking a question, then you end up lecturing
everyone because they allow their appliances to vent outside.
I hope you bank your savings because one appliance malfunction could require
this fund to bury some of your family. BTW, gas cooktops don't burn the gas
in an enclosed chamber so there is never a shortage of air, plus in my house
we run an exhaust fan that sends the products of combustion outside.
Also, keep note of the moisture that you are getting from the gas equipment
is acidic, so you will find it a little rough on the throat, lungs and will
rust any bare iron or steel objects in the building quicker than normal.
"Moe" <BubbleleLand@Fat.City> wrote in message
news:Tk1ki.2509$Sb4.2008@newsfe21.lga...
> lnh wrote:
> CO2? I drank a soda and was exposed to more CO2 then the space heaters
> and HWT will put out in a year. There was quite an argument about DC vs
> alternating current in the early 1900's because of the risk of high
> voltage AC current, the risk was determined to be worth the reward. I
> consider saving 30% on my natural gas bill each month well worth the risk.
> If burning natural gas was so dangerous everyone with a natural gas cook
> stove who ever warmed a can of beans would be dead by now. People don't
> understand risk, fear, emotions etc. This is so typical of the average
> American, drive a SUV because it is safer, but send troops to Iraq to
> get the needed crude supply for the SUV. How many people died in the USA
> last year due to unvented natural gas appliances and space heating? How
> many died in Iraq? How many people were electrocuted with AC current? I
> spend around 1000 a year on natural gas, it would be 1300 a year if I
> vented the stoves and HWT, take 300 times 20 years, that's 6K in
> expendable income. You can play with the numbers, invest it, collect
> interest on it, pay for a funeral with it, buy health insurance with it?
> Whatever,
> None are so blind as those that will not see.
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| daestrom 2007-07-09, 8:25 pm |
|
"Moe" <BubbleleLand@Fat.City> wrote in message
news:Tk1ki.2509$Sb4.2008@newsfe21.lga...
> lnh wrote:
> CO2? I drank a soda and was exposed to more CO2 then the space heaters
> and HWT will put out in a year.
Hmmm.... I doubt it. My summertime NG usage (just a HWT and stovetop) is
about 20 therms a month. So thats about 2000 cubic feet of methane.
Roughly speaking, one cubic foot of methane produces one cubic foot of CO2
if burned properly. So that's about 2000 cubic feet of CO2 in one month.
Admittedly, my family probably uses a fair amount of hotwater (family of
four), but it's clear that even a single person living alone produces more
CO2 from natural gas in a year then your soda can. Add on any significant
space-heating and you're much higher. My wintertime usage runs about 140
therms a month, so that would be about 14000 cubic feet of CO2 every month.
If your HWT has a recovery rate of 40,000 BTU/hr like mine does (and burns
natural gas), that is 0.4 Therms/hr and would be about 40 cubic feet of
methane per hour (more actually, since the unit isn't 100% efficient).
Those 40 cubic feet of methane generates about 40 cubic feet of CO2 and 80
cubic feet of water vapor. In doing so, it consumes about 80 cubic feet of
oxygen. Mind you, my HWT doesn't usually run for a full hour to recover
after someone takes a shower, but that gives you an idea of the rate.
There is a reason building codes require proper venting, but if you're so
much smarter then everyone else, by all means don't bother venting yours.
Just do your loved ones a favor and ask them to move out so they aren't
trapped in the same house.
BTW, learn the symptoms of CO2 poisoning versus CO poisoning. They *are*
different and a CO monitor will not protect from CO2. A well adjusted gas
appliance (that burns with a blue flame) generates very little CO but quite
a bit of CO2. But both gasses can be deadly.
<snip some rambling about risk and Iraq>
> None are so blind as those that will not see.
And because you can't see the CO2 coming from your appliances and it doesn't
show up on a CO monitor, you think it isn't there?
daestrom
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| daestrom wrote:
>
> "Moe" <BubbleleLand@Fat.City> wrote in message
> news:Tk1ki.2509$Sb4.2008@newsfe21.lga...
>
> Hmmm.... I doubt it. My summertime NG usage (just a HWT and stovetop)
> is about 20 therms a month. So thats about 2000 cubic feet of methane.
> Roughly speaking, one cubic foot of methane produces one cubic foot of
> CO2 if burned properly. So that's about 2000 cubic feet of CO2 in one
> month. Admittedly, my family probably uses a fair amount of hotwater
> (family of four), but it's clear that even a single person living alone
> produces more CO2 from natural gas in a year then your soda can. Add on
> any significant space-heating and you're much higher. My wintertime
> usage runs about 140 therms a month, so that would be about 14000 cubic
> feet of CO2 every month.
>
> If your HWT has a recovery rate of 40,000 BTU/hr like mine does (and
> burns natural gas), that is 0.4 Therms/hr and would be about 40 cubic
> feet of methane per hour (more actually, since the unit isn't 100%
> efficient). Those 40 cubic feet of methane generates about 40 cubic feet
> of CO2 and 80 cubic feet of water vapor. In doing so, it consumes about
> 80 cubic feet of oxygen. Mind you, my HWT doesn't usually run for a
> full hour to recover after someone takes a shower, but that gives you an
> idea of the rate.
>
> There is a reason building codes require proper venting, but if you're
> so much smarter then everyone else, by all means don't bother venting
> yours. Just do your loved ones a favor and ask them to move out so they
> aren't trapped in the same house.
>
> BTW, learn the symptoms of CO2 poisoning versus CO poisoning. They
> *are* different and a CO monitor will not protect from CO2. A well
> adjusted gas appliance (that burns with a blue flame) generates very
> little CO but quite a bit of CO2. But both gasses can be deadly.
>
> <snip some rambling about risk and Iraq>
>
>
> And because you can't see the CO2 coming from your appliances and it
> doesn't show up on a CO monitor, you think it isn't there?
>
> daestrom
>
Well, I'm still alive. After 21 years of heating the old place the
same old way. Exhaling CO2 all the while. I read up on CO2 and if I
ever have more then a 100 people in the house at one time I'll open a
window or two. Anyone know anything about cellulose insulation? Is it
better then fiberglass? I've heard it is.
| |
| philkryder 2007-07-15, 9:25 am |
| On Jul 4, 9:48 am, Moe <BubbleleL...@Fat.City> wrote:
> I was wondering,... my natural gas HWT is in the basement, would
> it be cost effective to install another one on the first floor and vent
> the lower tank through the floor to the second tank to prewarm or heat
> the water in the second tank? Would a power vent be needed to exhaust
> the fumes? The second floor tank would not have a burner but only be
> used to capture the wasted heat now going out the vent. Plumbing would
> be changed to go to the top tank first then the prewarmed water would go
> to the HWT.
Reading your post, I see you are asking about cost effectiveness.
Do you have cost numbers for the second tank?
Are you getting it free or buying at retail or what?
How much do you estimate for time and materials for cutting the holes
and running the vent pipes? Or, does the current vent pipe run through
the second floor already?
If so, how costly will it be for YOU to run the vent into the second
heater and seal it? and add the extra water plumbing?
You mention that you are already getting full use of the exhaust gas
heat in winter to heat under the house, so how many months out of the
year will you be running this configuration?
How much do you spend currently on heating water in the non-summer?
$30 or so per month?
Do you think you might save 20% of that?
I doubt it would be more than that.
$6 times 8 months would be about $50 per year.
That might pay for a water heater tank at retail.
Since it is under pressure, it won't have an unlimited life - but
since it has less thermal shock, it might last longer than "usual."
On the other hand the acidic condensation may be worse and shorten
life.
Regarding the fan, you seem fairly confident that you know how to
detect CO and the relative danger of CO2. If you are right, then you
can decide on the fan based on your own experience with your
configuration in your home.
That is probably more relevant than our opinions.
I assume none of this would be code.
I assume you don't care.
You might consider implications for your insurance, if that is a
concern to you.
It might also impact sale of the home.
Is the possibility of a second floor water tank leak a concern to you?
You can probably deal with that with proper leak detectors and shut-
offs and leak capture pans.
I will note that some of the early condensing furnaces had very high
efficiencies, but caused problems from acidic condensation rusting
even stainless exhaust stacks.
Would you feel comfortable as an alternative to counter flow the
exhaust from the existing heater DOWN through a second tank mounted
next to the existing heater and then use fan power to exhaust it under
the house. Would that give you enough heat in winter? You could then
perhaps use the same configuration year-around, which would have some
advantages.
Good luck and let us know what you decide and how it works for you.
Phil
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| daestrom 2007-07-16, 5:25 pm |
|
"Moe" <BubbleleLand@Fat.City> wrote in message
news:zHemi.14304$EZ1.10443@newsfe18.lga...
> daestrom wrote:
> Well, I'm still alive. After 21 years of heating the old place the same
> old way. Exhaling CO2 all the while. I read up on CO2 and if I ever
> have more then a 100 people in the house at one time I'll open a window or
> two. Anyone know anything about cellulose insulation? Is it better then
> fiberglass? I've heard it is.
As I recall, you said you unhook the HWT and let it heat *under* the house
in winter. That's not great, but it is far different then deliberately
venting *into* the house (via a second HWT). One reference I found says
humans normally generate about 450 liters/ day. That's a rate of about 0.66
ft^3 per hour. So a large HWT such as mine generates CO2 at a rate of about
the same as 60 people. So if you vent it directly into the house, open a
window every time it turns on. Good luck, don't kill yourself.
As to cellulose, it can be very good. It can seal around openings better
then fiberglass. But it does settle some so you have to use a bit more to
start with and make an allowance for some settling.
daestrom
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