Not many people have heard of them, they are a fairly new product category. They look just like a solar PV panel or solar hot water (without the tank) and are about the same size.
https://www.solarventinsw.com.au/
https://www.heatwithsolar.com.au/sam-solar-air-module/
Pumping air involves large capacity ducting which is going to be an eyesore running down the side of the building and also air is not a very good conductor of heat – See more at: http://www.flatchat.com.au/forum/is-it-really-easy-being-green/installing-solar-heating-how-to-proceed/#spPostForm
The warm air is pumped with a solar powered fan integrated in the panel. It does NOT rely on air conducting heat. There was a photo of one installation with a duct down the building, the duct looks just like normal PVC downpipe, about six inches across. Hardly an eyesore. I can’t find the photo now.
it only works when the sun is shining, not exactly the time that you really want space heating – See more at: http://www.flatchat.com.au/forum/is-it-really-easy-being-green/installing-solar-heating-how-to-proceed/#spPostForm
Sydney winter has plenty of sun, but it’s still cold…. 
???