Posted by *Nick Pine* on July 21, 2005, 9:31 am

. ----

. .

. . 30 F

. .

. .

. pond .

.-----------. ----

12' . s 4' . 12' 10.4'

. s .

<--S . s T .

. s . 6.92'

. s .

. s .

. s .

.duct duct.

----------------------------------------------------------------------

12'

We might build a 12'x16' equilateral A-frame with a 4'x12' shallow pond

at the top (view above, in a fixed font) and 2 poly film water ducts

along the north and south edges to avoid wind sliding and overturning...

20 psf makes 208 lb and 1082 ft-lb on each 1' EW slice of the greenhouse,

so we need 12W = 1082 ie W = 90 pounds of water in each foot of duct, eg

1.44 ft^3 of water in a 16" duct.

We could make each of the 10 slightly curved "half-bows" on 4' centers

with 2 12' 1x3s with 1x3 spacer blocks every 2' and a hinge at the top,

and use 3 horizontal 1x3 purlins.

The south side could have 80% shadecloth to make hot air rise under the

pond (which could be poly film over EPDM over foil over welded-wire fence.)

If we can somehow arrange that most of the greenhouse stays cooler while

the airpath between the shadecloth and glazing and under the pond is temp

T during the day, and the space above the pond is also temp T, we might

figure 0.9xsqrt(1000^2+620^2)12' = 12,712 Btu enters a 4' slice of south

glazing on an average 30 F Jan day in Phila, and 0.81^2x4x1177 = 3813 of

that enters the pond. At 130 F, it might also gain 6h(T-130)4ft^2x1.5

= 36T-4680 Btu/day from the bottom, and more, if the ground to the south

is reflective.

If the glazing loses 6h(T-30)12ft^2/R0.8 = 90T-2700 Btu/day and the daily

energy that flows into the slice equals the energy that flows out, 12712

= 3813+(36T-4680) + 90T-2700, so T = 129 F, and the pond slice gains about

3813 Btu, and 50K/3813 = 13.1', so a 16' greenhouse might provide most of

the heat in January. With about 3813x16'/6h = 10.2K Btu/h during solar

collection, 5 gpm (2400 Btu/h-F) would rise 4 F, and 400'x1/2" PE pipe

with 75 ft^2 of U30 surface would rise 10.2K/(75x30) = 5 F.

A row house with a flat roof might have a $8 12' diameter x 3' tall

EZ-Set pool in the basement with a $0 300'x1" fresh water pressurized

PE pipe heat exchanger near the top of the pool under floating Styrofoam

and a low-head pump with a $0 400'x1/2" PE pipe heat exchanger in the

pool bottom. With lots of insulation and 0.8xPi(11/2)^2x3x62.33 = 14216

pounds of water at 110 F after 5 cloudy days, after supplying 5x50K Btu,

it needs to be 110+250K/14216 = 128 F on an average day. Then again, it

might melt :-) It might need reinforcing, eg a tarp tied up around it.

Or maybe we need a different kind of pool.

This might also be a standalone structure in a yard, with the filter pump

that comes with the pool.

Nick

Posted by *George Ghio* on July 21, 2005, 12:45 pm

Nick Pine wrote:

*> . ----*

*> . .*

*> . . 30 F*

*> . .*

*> . .*

*> . pond .*

*> .-----------. ---- *

*> 12' . s 4' . 12' 10.4'*

*> . s .*

*> <--S . s T . *

*> . s . 6.92'*

*> . s .*

*> . s .*

*> . s .*

*> .duct duct.*

*> ----------------------------------------------------------------------*

*> 12'*

*> *

*> We might build a 12'x16' equilateral A-frame with a 4'x12' shallow pond*

*> at the top (view above, in a fixed font) and 2 poly film water ducts*

*> along the north and south edges to avoid wind sliding and overturning...*

*> 20 psf makes 208 lb and 1082 ft-lb on each 1' EW slice of the greenhouse,*

*> so we need 12W = 1082 ie W = 90 pounds of water in each foot of duct, eg*

*> 1.44 ft^3 of water in a 16" duct. *

*> *

*> We could make each of the 10 slightly curved "half-bows" on 4' centers*

*> with 2 12' 1x3s with 1x3 spacer blocks every 2' and a hinge at the top,*

*> and use 3 horizontal 1x3 purlins. *

*> *

*> The south side could have 80% shadecloth to make hot air rise under the*

*> pond (which could be poly film over EPDM over foil over welded-wire fence.)*

*> *

*> If we can somehow arrange that most of the greenhouse stays cooler while*

*> the airpath between the shadecloth and glazing and under the pond is temp*

*> T during the day, and the space above the pond is also temp T, we might *

*> figure 0.9xsqrt(1000^2+620^2)12' = 12,712 Btu enters a 4' slice of south*

*> glazing on an average 30 F Jan day in Phila, and 0.81^2x4x1177 = 3813 of*

*> that enters the pond. At 130 F, it might also gain 6h(T-130)4ft^2x1.5*

*> = 36T-4680 Btu/day from the bottom, and more, if the ground to the south*

*> is reflective.*

*> *

*> If the glazing loses 6h(T-30)12ft^2/R0.8 = 90T-2700 Btu/day and the daily*

*> energy that flows into the slice equals the energy that flows out, 12712*

*> = 3813+(36T-4680) + 90T-2700, so T = 129 F, and the pond slice gains about*

*> 3813 Btu, and 50K/3813 = 13.1', so a 16' greenhouse might provide most of*

*> the heat in January. With about 3813x16'/6h = 10.2K Btu/h during solar*

*> collection, 5 gpm (2400 Btu/h-F) would rise 4 F, and 400'x1/2" PE pipe*

*> with 75 ft^2 of U30 surface would rise 10.2K/(75x30) = 5 F.*

*> *

*> A row house with a flat roof might have a $8 12' diameter x 3' tall*

*> EZ-Set pool in the basement with a $0 300'x1" fresh water pressurized*

*> PE pipe heat exchanger near the top of the pool under floating Styrofoam*

*> and a low-head pump with a $0 400'x1/2" PE pipe heat exchanger in the*

*> pool bottom. With lots of insulation and 0.8xPi(11/2)^2x3x62.33 = 14216*

*> pounds of water at 110 F after 5 cloudy days, after supplying 5x50K Btu,*

*> it needs to be 110+250K/14216 = 128 F on an average day. Then again, it*

*> might melt :-) It might need reinforcing, eg a tarp tied up around it.*

*> Or maybe we need a different kind of pool.*

*> *

*> This might also be a standalone structure in a yard, with the filter pump*

*> that comes with the pool.*

*> *

*> Nick*

*> *

You used the word "Might" 8 times, "Could" 3 times, "If" 3 times, with a

"Maybe" and "Somehow" once each.

"Could" it be that you "Might" be proposing that "If" "Somehow" you

"Maybe" actually built one you could prove your point without using

those words that only confirm that you are in fact just guessing.

Posted by *News* on July 21, 2005, 1:41 pm

*> Nick Pine wrote:*

*> > . ----*

*> > . .*

*> > . . 30 F*

*> > . .*

*> > . .*

*> > . pond .*

*> > .-----------. ----*

*> > 12' . s 4' . 12' 10.4'*

*> > . s .*

*> > <--S . s T .*

*> > . s . 6.92'*

*> > . s .*

*> > . s .*

*> > . s .*

*> > .duct duct.*

*> > ----------------------------------------------------------------------*

*> > 12'*

*> >*

*> > We might build a 12'x16' equilateral A-frame with a 4'x12' shallow pond*

*> > at the top (view above, in a fixed font) and 2 poly film water ducts*

*> > along the north and south edges to avoid wind sliding and overturning...*

*> > 20 psf makes 208 lb and 1082 ft-lb on each 1' EW slice of the*

greenhouse,

*> > so we need 12W = 1082 ie W = 90 pounds of water in each foot of duct, eg*

*> > 1.44 ft^3 of water in a 16" duct.*

*> >*

*> > We could make each of the 10 slightly curved "half-bows" on 4' centers*

*> > with 2 12' 1x3s with 1x3 spacer blocks every 2' and a hinge at the top,*

*> > and use 3 horizontal 1x3 purlins.*

*> >*

*> > The south side could have 80% shadecloth to make hot air rise under the*

*> > pond (which could be poly film over EPDM over foil over welded-wire*

fence.)

*> >*

*> > If we can somehow arrange that most of the greenhouse stays cooler while*

*> > the airpath between the shadecloth and glazing and under the pond is*

temp

*> > T during the day, and the space above the pond is also temp T, we might*

*> > figure 0.9xsqrt(1000^2+620^2)12' = 12,712 Btu enters a 4' slice of south*

*> > glazing on an average 30 F Jan day in Phila, and 0.81^2x4x1177 = 3813 of*

*> > that enters the pond. At 130 F, it might also gain 6h(T-130)4ft^2x1.5*

*> > = 36T-4680 Btu/day from the bottom, and more, if the ground to the south*

*> > is reflective.*

*> >*

*> > If the glazing loses 6h(T-30)12ft^2/R0.8 = 90T-2700 Btu/day and the*

daily

*> > energy that flows into the slice equals the energy that flows out, 12712*

*> > = 3813+(36T-4680) + 90T-2700, so T = 129 F, and the pond slice gains*

about

*> > 3813 Btu, and 50K/3813 = 13.1', so a 16' greenhouse might provide most*

of

*> > the heat in January. With about 3813x16'/6h = 10.2K Btu/h during solar*

*> > collection, 5 gpm (2400 Btu/h-F) would rise 4 F, and 400'x1/2" PE pipe*

*> > with 75 ft^2 of U30 surface would rise 10.2K/(75x30) = 5 F.*

*> >*

*> > A row house with a flat roof might have a $8 12' diameter x 3' tall*

*> > EZ-Set pool in the basement with a $0 300'x1" fresh water pressurized*

*> > PE pipe heat exchanger near the top of the pool under floating Styrofoam*

*> > and a low-head pump with a $0 400'x1/2" PE pipe heat exchanger in the*

*> > pool bottom. With lots of insulation and 0.8xPi(11/2)^2x3x62.33 = 14216*

*> > pounds of water at 110 F after 5 cloudy days, after supplying 5x50K Btu,*

*> > it needs to be 110+250K/14216 = 128 F on an average day. Then again, it*

*> > might melt :-) It might need reinforcing, eg a tarp tied up around it.*

*> > Or maybe we need a different kind of pool.*

*> >*

*> > This might also be a standalone structure in a yard, with the filter*

pump

*> > that comes with the pool.*

*> >*

*> > Nick*

*> >*

*> You used the word "Might" 8 times, "Could" 3 times, "If" 3 times, with a*

*> "Maybe" and "Somehow" once each.*

*> "Could" it be that you "Might" be proposing that "If" "Somehow" you*

*> "Maybe" actually built one you could prove your point without using*

*> those words that only confirm that you are in fact just guessing.*

LOL, that was good. Nothing personal Nick. :-)

Posted by *nicksanspam* on July 21, 2005, 2:17 pm

*>> . ----*

*>> . .*

*>> . . 30 F*

*>> . .*

*>> . .*

*>> . pond .*

*>> .-----------. ---- *

*>> 12' . s 4' . 12' 10.4'*

*>> . s .*

*>> <--S . s T . *

*>> . s . 6.92'*

*>> . s .*

*>> . s .*

*>> . s .*

*>> .duct duct.*

*>> ----------------------------------------------------------------------*

*>> 12'*

*>> *

*>> We might build a 12'x16' equilateral A-frame...*

*>You used the word "Might" 8 times, "Could" 3 times, "If" 3 times, with a *

*>"Maybe" and "Somehow" once each.*

Thank you for counting.

*>"Could" it be that you "Might" be proposing that "If" "Somehow" you *

*>"Maybe" actually built one you could prove your point without using *

*>those words that only confirm that you are in fact just guessing.*

The only big risk is the plastic pool losing strength at 130 F, and there

are solutions for that. I go overboard on the "mights" to avoid ignorant

people like you raising angry challenges to 300-year-old settled physics.

Nick

Posted by *Ed Earl Ross* on July 21, 2005, 4:06 pm

nicksanspam@ece.villanova.edu wrote:

*> *

*> *

*>>> . ----*

*>>> . .*

*>>> . . 30 F*

*>>> . .*

*>>> . .*

*>>> . pond .*

*>>> .-----------. ---- *

*>>> 12' . s 4' . 12' 10.4'*

*>>> . s .*

*>>> <--S . s T . *

*>>> . s . 6.92'*

*>>> . s .*

*>>> . s .*

*>>> . s .*

*>>> .duct duct.*

*>>>----------------------------------------------------------------------*

*>>> 12'*

*>>>*

*>>>We might build a 12'x16' equilateral A-frame...*

*> *

*> *

*>>You used the word "Might" 8 times, "Could" 3 times, "If" 3 times, with a *

*>>"Maybe" and "Somehow" once each.*

*> *

*> *

*> Thank you for counting.*

*> *

*> *

*>>"Could" it be that you "Might" be proposing that "If" "Somehow" you *

*>>"Maybe" actually built one you could prove your point without using *

*>>those words that only confirm that you are in fact just guessing.*

*> *

*> *

*> The only big risk is the plastic pool losing strength at 130 F, and there*

*> are solutions for that. I go overboard on the "mights" to avoid ignorant*

*> people like you raising angry challenges to 300-year-old settled physics. *

Perhaps a scale model would help settle the mights, coulds and maybes.

--

Humbly--Ed

"If the man doesn't believe as we do,

we say he is a crank, and that settles it.

I mean, it does nowadays, because now we

can't burn him." (Mark Twain)

> . ----> . .> . . 30 F> . .> . .> . pond .> .-----------. ----> 12' . s 4' . 12' 10.4'> . s .> <--S . s T .> . s . 6.92'> . s .> . s .> . s .> .duct duct.> ----------------------------------------------------------------------> 12'>> We might build a 12'x16' equilateral A-frame with a 4'x12' shallow pond> at the top (view above, in a fixed font) and 2 poly film water ducts> along the north and south edges to avoid wind sliding and overturning...> 20 psf makes 208 lb and 1082 ft-lb on each 1' EW slice of the greenhouse,> so we need 12W = 1082 ie W = 90 pounds of water in each foot of duct, eg> 1.44 ft^3 of water in a 16" duct.>> We could make each of the 10 slightly curved "half-bows" on 4' centers> with 2 12' 1x3s with 1x3 spacer blocks every 2' and a hinge at the top,> and use 3 horizontal 1x3 purlins.>> The south side could have 80% shadecloth to make hot air rise under the> pond (which could be poly film over EPDM over foil over welded-wire fence.)>> If we can somehow arrange that most of the greenhouse stays cooler while> the airpath between the shadecloth and glazing and under the pond is temp> T during the day, and the space above the pond is also temp T, we might> figure 0.9xsqrt(1000^2+620^2)12' = 12,712 Btu enters a 4' slice of south> glazing on an average 30 F Jan day in Phila, and 0.81^2x4x1177 = 3813 of> that enters the pond. At 130 F, it might also gain 6h(T-130)4ft^2x1.5> = 36T-4680 Btu/day from the bottom, and more, if the ground to the south> is reflective.>> If the glazing loses 6h(T-30)12ft^2/R0.8 = 90T-2700 Btu/day and the daily> energy that flows into the slice equals the energy that flows out, 12712> = 3813+(36T-4680) + 90T-2700, so T = 129 F, and the pond slice gains about> 3813 Btu, and 50K/3813 = 13.1', so a 16' greenhouse might provide most of> the heat in January. With about 3813x16'/6h = 10.2K Btu/h during solar> collection, 5 gpm (2400 Btu/h-F) would rise 4 F, and 400'x1/2" PE pipe> with 75 ft^2 of U30 surface would rise 10.2K/(75x30) = 5 F.>> A row house with a flat roof might have a $8 12' diameter x 3' tall> EZ-Set pool in the basement with a $0 300'x1" fresh water pressurized> PE pipe heat exchanger near the top of the pool under floating Styrofoam> and a low-head pump with a $0 400'x1/2" PE pipe heat exchanger in the> pool bottom. With lots of insulation and 0.8xPi(11/2)^2x3x62.33 = 14216> pounds of water at 110 F after 5 cloudy days, after supplying 5x50K Btu,> it needs to be 110+250K/14216 = 128 F on an average day. Then again, it> might melt :-) It might need reinforcing, eg a tarp tied up around it.> Or maybe we need a different kind of pool.>> This might also be a standalone structure in a yard, with the filter pump> that comes with the pool.>> Nick>