Quote:
Originally Posted by Terry B
I just used second hand colourbond sheeting with the corrugations horizontal. This is suppose to create a little shadowing when the sun is high reducing the heating slightly. I haven't lined the walls. It cools off very quickly. Insulation might slow down the cooling off. Professional observatories refrigerate the inside during the day to beat the cooling off. This is a bit over the top for a little observatory.
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Air refrigerating the observatory during the hot days of summer is an idea.
Wouldn't be hard to do , all you need is 240VAC to the observatory and one of those small window mounted refrigerative airconditioners (0.5 HP), cut a hole in a convenient wall install a power point with a timer (to turn it on during the daylight hours) , direct the airflow at the slab , and hey presto .... one nice cool (or cooler) observatory slab at night.
Something I might do if I settle on a concrete slab , I happen to have an old window mounted airconditioner that used to live in a hole in the main bedroom wall (until I upgraded to a 2.4 HP split reverse cycle to cool / heat the entire house and insulated my walls when recladding, and insulated the ceilings).
It still works too despite being 30 years old, I recently powered it up and was pleased it still works (pays to hold onto these kind of things when they become redundant), was considering partitioning and lining and insulating part of the double garage for use as a study and cooling it.
Since changed my mind - I desire a permanent home for my telescopss more.
corrugations horizontal idea , more likely the corrugations orientated horizontally enhances turbulent air flow rather than the laminar airflow you'd get if the corrugations were orientated vertically (or you had a non-corrugated sheet of metal, I'm a bit rusty on convection cooling under laminar and turbulent flow conditions) , a higher Stanton number due to turbulent air flow (the air has to rise boyantly over a longer length of metal (higher velocity wrt the metal) results in a higher rate of heat transfer).
I am not sure if sufficent shadowing of the metal surface by the corrugations on a vertical sheet whith corrugations oriented horizontally will really have that much effect, the radiant heating by the sun would see essentially a vertical sheet of metal (though the view angles would vary some being very close to parallel with the sun's rays, some not.
Also as the surface of the metal warms , thermal conduction will even out the lit side of the shed's wall's surfaces temperature considerably too.
is considerably reduced & does not get into the obs as much
