re: advice sought on passive solar design
13 feb 2003
m russon wrote:
> would you say that a solar sunspace is best utilized when the heat
>from the space is taken via ductwork from the space into the living
>areas as actively as possible during the best heating hours of the day?
sure, altho a higher sunspace temp can make air flow passively thru plastic
film one-way dampers over vents at the top and bottom with less fan power
and less thermal efficiency. if a ft^2 of r1 south glazing with 90% solar
transmission in full sun loses (100-30)a/r1 btu/h in a 100 f sunspace with
30 f air outdoors, we need av ft^2 of vents 16' below av ft^2 of upper vents,
where 225a-(100-30)a = 16.6avsqrt(16')(100-70)^1.5, so av = 0.014a, eg 7.3
ft^2 vents in a 32'x16' sunspace.
a mesh or an inner glazing near the north wall can collect higher temp
heat while keeping a sunspace cool and more comfortable for people.
>it would seem to me that actively dispersing the heat to the living area
>during the day, and closing off the sunpace at night would be the most
>effective use of the space, other than growing some nice plantlife.
the average jan temp is 30 f where i live in phila. leaking a little warm
house air into a sunspace to keep it from freezing on a cold night isn't
a large thermal penalty.