re: living out of a van SOLAR.KnowledgePublications.com

re: living out of a van
24 dec 2003
127.0.0.1  <127.0.0.1> wrote:

>nicksanspam@ece.villanova.edu wrote:
>
>>reading all this reminds me again of all the unused flat rooftops in nyc.
>>a body might build an inexpensive portable illegal shelter on one that's
>>higher than nearby buildings (to avoid reporting by neighbors) and live
>>there until found out, then move on to another rooftop...
>>
>>i picture a plastic film greenhouse, quonset-style, say 8'x12', with
>>a waterbed inside. electricity and potable water might come from a small
>>plastic tube and an extension cord to a confederate below, the toilet
>>might be boat us item 193033, $19.99, shipping weight 0.5 lb. ("easily
>>carried and stored, the white bucket potty seat attaches to your 3- or
>>5-gallon bucket...") the ballast foundation could be two plastic film
>>ducts laid flat on the roof... heat would be solar...automatically
>>filling the space between two plastic film greenhouse covers with air
>>during the day and soap-bubble foam at night, and vice-versa in summer.
>>i picture draining all this and packing it into a suitcase to move.

>and just how do you plan to sneak all that stuff up to a roof of a
>building where you don't belong in?

systeme d, in a suitcase, with the help of the aforementioned confederate.
("yes, i told george he could camp on the roof.") an 8'widex12'longx8'tall
paraboloid structure with 2 309 ft^2 layers of 6 mil poly film might weigh
2x309x0.027 = 16.7 pounds.

a 90 mph wind might push with 12x8x20.7 = 1987 pounds of force, so we need
about 31 ft^3 of water inside to resist sliding, with a unity coefficient
of friction.

nrel says 610 btu/ft^2 of sun falls on the ground and 980 falls on a south
wall on an average 31.5 f january day in nyc. a cubic foot of water inside
concentric poly film ducts (the outer one filled with air for better room
temp control) would receive about 0.9^4(610+980) = 1043 btu of sun on an
average day. at water temp t, it would lose about 24h(t-65)4ft^2/r1, making
t = 130 f on an average day. surrounded by 6" r20 foam, the structure would
lose about 5x24h(65-31.5)309ft^2/r20 = 62k btu over 5 cloudy days, which
might come from 62k/(130-70) = 1033 pounds of water cooling from 130 to 70 f.

nick