Solar Warm Air Panel: Window Box

An Eccentric Anomaly: Ed Davies's Blog

The solar warm air collector is now at version 1.0. Previously: part 1, 1.5, 1.6 and initial results.

The weather has been pretty poor, though with a few nice days. Unfortunately, the nicest last week were Monday when I had a hospital appointment 40 miles away so all I managed on the solar warm air panel was to buy some more draft extruder strip and Thursday when I woke feeling very depressed and only got a little bit done - I slept most of the afternoon.

Consequently I got the box to feed the warm air into the bathroom window done midday Sunday, just as the sun was far enough round to the west not to be on the panel.

The box is a fairly firm push fit so doesn't affect the house at all. I may need to block the small air paths round the side of it at some point.

There's a somewhat intricate cut out at the bottom which fits the top of the collector box itself.

On Monday I also visited the agricultural supplies place to see if they had any of the "wiggle strips" to seal the bottom of the corrugated PVC. Unfortunately, they only had them for the larger size corrugations. When I felt them I was surprised how soft they were but I now see why: when I tried a slice of pipe insulation it was too stiff to fill the hills of the corrugations without lifting the valleys too high off the ply behind.

I just put some draft extruder there for now but may well add something else at some point. I thought of squirty foam but I think it'll just go brown and brittle from UV exposure.

Still, I used the other part of the pipe insulation to fill the gap between the bottom "shelf" of the box and the window sill.

Having got this in place on Sunday after the sun had gone round, Monday was, as you might expect, horribly wet and dark. Today, Tuesday, was quite a bit better though quite breezy from the south west. The temperatures in the collector were quite reasonable, in the mid thirties, but the effect on the bathroom was pretty disappointing. My initial suspicion is that the wind is causing the airflow to be actually be out of the bathroom and through the collector in reverse. More when I've had a few days more experience.