On a recent trip I picked up this little USB powered fan.
It seems very similar to the USB light.
I have used it on all roasts since I got back, I have found it does help the cooling.
My only learning is that if you are cooling a natural process and there is lots of chaff, possibly just use the inbuilt fan in the tray as it will hold the chaff in the tray.
On washed and honey processed coffee’s it works well.
It was super cheap…
I found a seller in Singapore that sells them.