Quite a few of our Prior DIY conservatories are South facing and as a result of the heat build up in summer, we regularly supply them with roof vents. These are ideal for letting the heat out from the top of the conservatory and thus generating a gentle breeze from the French doors and other opening windows.
These vents come in various flavours from manually operated by means of a brass or anodized pole connecting to a worm gear to electrically operated ones. The manually operated ones are the cheapest and are solid and easy to operate. The electric ones are as before but without the need for the pole. Switch operated they open fully in seconds. There is another electric version which is simplicity its self to use. These are rain sensor vents and open automatically and will close at the first hint of rain.
Whichever model you choose, they do make a significant difference on a hot day, particularly on the high roofed conservatories such as a gable fronted, Edwardian and Victorian.