re: homemade solar pool heater?
27 jun 2004
>i have a above ground pool and would like to make a solar pool heater for it.
>not sure how to go about it... any recommendations?
greenhouse polyethylene film (5 cents/ft^2 in wide rolls with a 4 year
guarantee) has lots of longwave ir transmission (ie little "greenhouse
effect"), so it's unlikely to overheat a roof, altho it can become brittle
over time, if it's touching a dark surface, and it sags a lot when it's
warm and it's subject to wind fatigue, esp if it's installed in flat
vs curved sheets.
how can we support it over a dark asphalt roof to make a trickle collector,
with a pipe full of holes along the ridgeline and a gutter at the eave? it
might be pressurized with a small blower (as in a greenhouse) that turns on
when the water is running or it's very windy (>10 mph) outside or very hot
(>150 f) inside. some web straps over the film might help prevent outward
ballooning. harry thomason noted that trickling water spread nicely into a
uniform film over asphalt roofs (which he used for evaporative cooling at
night), but the asphalt shingles overheated when he added glass...