Think of this:

A home has electrically driven window blinds (shutters?)

Windows are located to east/south and west.

Daytime:

Open blinds if environmental light is above threshold

IF outside temperature is low (ie winter), or maybe if outside temp is < inside temp, then blinds must open if sun is shining, so you economise energy.

If outside temperature is > inside temp (ie summer) then blinds must go down is sun is shining to "control" inside temperature.

Night-time:

If environmental light drops below threshold, shut blinds

Oh yes, don't forget security measures (ie blinds are blocked for some reason and cannot open/shut).

You could even try fuzzy logic to control the lot.

regards
Patrick