How summer is coming and plenty of hard work to do outside.
Our head/brain is probably first to overheat and fail in hyperthermia conditions. So cooling it down provide not only comfort but also life saving.
My hard hut is still at prototype stage,
but works fine and hard already for me 4 years...

standard computer fan 12V , low noise, big airflow, less power consumption

powered by 2 x lithium batteries 18650 providing 7.2Vbattery last for whole working 8h day or two days

planned upgrade to solar panel to recharge battery,
provide indefinite run time outside,
small protecting board $2 device needed to protect battery from over / diss/ charging.
So far I could not find anything already professionally designed and build on the market.
Some Chinese made huts with small and noisy fan at the front. Get one of eBay, but doesn't do job.
PS. I agree already with all my critics. This idea is so obvious that should be available at Bunnings already, with some professional design improvements obviously.