Whirlybirds or wind driven fans have been around permanently, but there has been lots of discussion about solar powered roof ventilators.
Essentially, the main focus at the moment is about the amount of air moved by the different roof ventilation fan types available. Roof ventilation
The typical domestic whirlybird moves around 100 cbm/h - at around 12 km/h wind speeds. It's difficult to find this sort of data in the manufacturers with the wind driven fans - but there appears to be a consensus when surveying the various solar powered roof ventilation fan options which they - depending on their airflow capacity at 0 pressure capacity matches that relating to 10 to 30 whirly birds. Solar whirlybird
This can be in line with data published a while back after a conference in the Queensland University of technology by Shane West, from University of Technology, Sydney.
The only wind driven fans with capacities comparable to solar roof ventilation fans, are Industrial whirlybirds, that can come in a number of sizes and capacities - but when again - it really is difficult to find data.
Australia wide - probably the most well-known Industrial type will be the Edmonds branded 900 mm Edmonds Hurricane (No Whirlybirds)Hurricane with a capacity of 2700 cbm/h at 12 km/h wind speed and 3400 cbm/h at 16 km/h. The issue is obviously they count on the wind - and it may or may not be windy around the hot days when roof ventilation is necessary the most.
Right now - it is most unusual to see what is normally known as industrial whirlybirds used on homes - and also offices, daycare institutions, retirement villages etc. - you actually only see these large units employed for industrial ventilation of warehouses and ventilation of factories.
However, should you be looking for wind driven roof ventilation matching the solar ventilation alternatives - you should look at the large industrial whirly bird varieties which aren�t generally bought at places like Bunnings and Masters and installation Melbourne.