re: roof solar panel for pool
19 feb 2002
derek long wrote:
>...i'm in the uk and have just put our pool indoors 24' x 12' x 4' deep
>the pool room is fully insulated with 6" rockwool...
assuming minimal ventilation and high indoor humidity, you might figure
most of the heat loss is through the ceiling and walls of the room, say
24'x12'/r20 = 14.4 btu/h-f for the ceiling and 2(24+12)8/r20 = 28.8 for
the walls (with no windows?), a total of 43.2 btu/h-f.
>...we would like to put a roof solar panel about half the pool area on
>the roof which is south facing.
what's the average temp in january and how much sun you get on the roof
on an average day? we get about 1200 btu/ft^2-day on a 45 degree south
slope on an average 30 f day in january in phila. with one layer of r1
glazing with 90% solar transmission, we might collect 1060 btu/ft^2 of
sun in 130 f water and lose about 6h(130-30)/r1 = 600 on an average day.
a 24'x8' surface might gain 88.3k btu and keep the pool t (f), where
88.3k = 24h(t-30)43.2, so t = 30+88.3k/(24x43.2) = 115 f :-)