That is a nice bit of work @tallpaul. Those pics were useful too @haloric. I'd like to have a go at making my own I think.
I'm in a shed and use a pretty small Honeywell turbo fan which works for riding in the winter months, though at the moment I can manage without for the first half of a session since it's pretty nippy and the shed is uninsulated.
Taotronics pedestal fan more than enough for winter, in warmer turbo sessions I'll use another pedestal fan or the Honeywell HT900E as an extra.
I wouldn't stop at "just" one fan. Don't mess around with little weedy desk fans, you need some fairly serious air moving power if you're going to be working hard. It also depends how much you are willing to spend.
I've got a cheapish screwfix one on a smart plug that works great, and a wahoo headwind that is similar but betterer in terms of features - more focussed airflow to hit just your body, and ability to control it via phone app or via heart rate. I'm keeping both for extreme summer days when you just want as much airflow as you can get.
I wouldn't recommend one or the other, it just depends on your budget.
If anyone is in Leeds I have one of those 18" Screwfix floor fans going spare. You can have it for a £10 donation to charity.
3 speed floor fan, I always have it on highest setting…even when it’s super cold in the garage, hat and gloves on until I’m warmed up a bit and can face the arctic blast 😁
Same as DrP for me - big floor fan, hung off the wall in front of me. Plugged into an extension cord with switches which I can reach while riding.
Set to speed 1 in the winter; if it's cold enough i'll just use it in bursts. Up to 2 or 3 in the summer, but I'm not so likely to be on Zwift in the first place.
I went all posh and got the Wahoo Headwind. It's great. I have it set up to respond to heart rate, so it's one less remote to faff with.
Also have a cheapo floor-standing job that provides a higher volume of air movement, but at a much lower flow rate. The Headwind provides a very powerful, yet concentrated stream of air.