Solar water heaters - Re: Wonder if they stink?
in [Frugal Living]
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From: Morris Dovey on 22 Dec 2006 07:49 James (in 1166647866.172409.28980(a)73g2000cwn.googlegroups.com) said: | Anyone have info on capacity of solar water heaters? It's probably | not too hard to provide couple hundred gallons of bath water for a | family of 5 but what would be required for a bathhouse serving a | whole village who probably want to bathe after sundown? | | Perhaps they get a quick wash with a few gallons and then enjoy | soaking in a big hottub. [posting from alt.solar.thermal] Short answer: Heating capacity is determined by the available solar energy, the capture area and efficiency of the solar panel, and the ability of the storage tank to retain heat. If there is sufficient solar radiation, a panel with sufficient capture area and reasonable efficiency, and a well-insulated storage tank, then there's no reason that a bathhouse could not supply heated water for an entire village... -- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/solar.html
From: nicksanspam on 22 Dec 2006 12:53 Morris Dovey <mrdovey(a)iedu.com> wrote: >James (in 1166647866.172409.28980(a)73g2000cwn.googlegroups.com) said: > >| Anyone have info on capacity of solar water heaters? It's probably >| not too hard to provide couple hundred gallons of bath water for a >| family of 5 but what would be required for a bathhouse serving a >| whole village who probably want to bathe after sundown? >| >| Perhaps they get a quick wash with a few gallons and then enjoy >| soaking in a big hottub. Sounds nice :-) >Short answer: > >Heating capacity is determined by the available solar energy, the >capture area and efficiency of the solar panel, and the ability of the >storage tank to retain heat. > >If there is sufficient solar radiation, a panel with sufficient >capture area and reasonable efficiency, and a well-insulated storage >tank, then there's no reason that a bathhouse could not supply heated >water for an entire village... A friend just installed a solar water heater for a 15-apartment building near Phila, with an 822 gallon STSS tank (55 gallons per unit) and evacuated tube collectors. He was surprised by the high cost of materials and the large amount of labor required. Given lots of lawn or flat roof space, we might put a few shallow ponds with 2" foamboard draindown covers under a plastic film greenhouse with a reflective south wall, but that space might be hard to find in an area dense enough for apartment living. Better to find a building that needs a new steep south roof and replace it with $1/ft^2 Dynaglas, with $2/ft slow-draindown fin-tube pipe under the ridge and a $500 24' diameter x 4' deep swimming pool in the basement with 15 $60 300'x1" PE pressurized pipe coils in the pool to preheat cold water? NREL says 620 Btu/ft^2 of sun falls on the ground and 1000 falls on a south wall on a 30 F average January day with a 38 F daily max in Phila, so 1177 =sqrt(620^2+1000^2) might fall on well-sloped glazing. With R2 glazing, 80% of that might heat 100 F average water over 6 hours when it's 34 F outdoors, for a net gain of 941-6h(100-34)1ft^2/R2 = 653 Btu/ft^2day. If each unit uses 50K Btu/day of hot water, we need 15x50K/653 = 1148 ft^2 of glazing, eg a 12' tall x 96' long greenhouse. H. Schwartz & Sons of Wilmington, DE (302) 656-0276 sold 14' wide x 9' tall x 96' long gothic-arched coldframes for $699, with steel pipe bows on 4'- centers that bolt into ground pipes. For a little more money, longer ground pipes can make them taller. A 4-year plastic cover costs about 5 cent/ft^2. We might whitewash the inside of the north wall. A 2'-deep x 12' wide x 92' long poly-film-lined well-insulated welded-wire- fence tank with 2x12x92x62.33 = 138K pounds of water cooling from 140 F on an average day to 60 after 5 cloudy days can supply (140-60)138K = 11 million Btu of solar hot water. It might supply 100% of the hot water on the first cloudy day (with probability 1/2, if cloudy days were coin flips) and cool to 140-15x50K/138K = 135 F. On the second day (probability 1/4), it might supply 100% of the hot water and cool to 135-15x50K/138K = 129, and so on, ie it might supply close to 100% of the hot water need in January. Nick
From: Morris Dovey on 22 Dec 2006 14:10 nicksanspam(a)ece.villanova.edu (in emh63d$h6q(a)acadia.ece.villanova.edu) said: Hey, Nick! What version of BASIC are you using? I'd like to try out some of the programs you've posted - is there a freeware interpreter I can download that'll do the job? Do you have a URL? -- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/solar.html
From: Duane C. Johnson on 22 Dec 2006 20:33 Hi Morris; I'm also a great fan of basic for simple easily readable programs. Morris Dovey wrote: > <nicksanspam(a)ece.villanova.edu> said: > Hey, Nick! What version of BASIC are you using? > I'd like to try out some of the programs you've > posted - is there a freeware interpreter I can > download that'll do the job? Do you have a URL? These programs are now in the public domain, (I think). http://en.wikipedia.org/wiki/Microsoft_GW-BASIC_interpreter GW-BASIC http://www.geocities.com/KindlyRat/GWBASIC.html And a compeller called QBasic. http://en.wikipedia.org/wiki/QBasic http://www.geocities.com/area51/5967/qbasic.html > -- > Morris Dovey > DeSoto Solar > DeSoto, Iowa USA > http://www.iedu.com/DeSoto/solar.html Duane -- Home of the $35 Solar Tracker Receiver http://www.redrok.com/led3xassm.htm [*] Powered by \ \ \ //| Thermonuclear Solar Energy from the Sun / | Energy (the SUN) \ \ \ / / | Red Rock Energy \ \ / / | Duane C. Johnson Designer \ \ / \ / | 1825 Florence St Heliostat,Control,& Mounts | White Bear Lake, Minnesota === \ / \ | USA 55110-3364 === \ | (651)426-4766 use Courier New Font \ | redrok(a)redrok.com (my email: address) \ | http://www.redrok.com (Web site) ===
From: Anthony Matonak on 22 Dec 2006 23:36
Morris Dovey wrote: > Hey, Nick! What version of BASIC are you using? I'd like to try out > some of the programs you've posted - is there a freeware interpreter I > can download that'll do the job? Do you have a URL? A quick google search got me these webpages. http://www.thefreecountry.com/compilers/basic.shtml http://www.nicholson.com/rhn/basic/ http://www.freebyte.com/programming/ http://www.idiom.com/free-compilers/ Also of note is that Basic was included in the Rom's of the early PC computers and also included in various versions of Dos and CP/M. Anthony |