Here in Texas we have playgrounds with stretched tarps over them. I wonder how much it would help a home energy use to have similar tarps inches above the roof giving the whole structure shade throughout the day.
These allowed the venting air to be shut off in winter and opened in summer. giving you great insulation or ventilation. Combined with the many other things they did (vines in front of walls for summer heat blockages, A well populated garden of low water plants, good insulation everywhere, a white painted roof and double glazed windows) meant that for most of the year no active cooling or heating was required.
And this was a place that commonly sees winters with lows of -10 and summers with periods of +35 as the nightly low (daily maxes are +40 for 2 to 3 weeks at a time (Air drying clothes in summer generally took less time than hanging them out. :| ))
Much nicer than the typical house in central Australia.