This might be a lost cause, but I’m looking for small & medium (so max 1A and max 2.4A power draw) USB fans without a battery (corded power only) which will last more than 1 to 2 seasons even at a 90% duty cycle. USB fans are a common enough item that unusually good ones may exist, but it’s really hard to find any amid the tsunami of cheap trash.
Yes I’m aware cheap DC motors don’t last, I have my reasons for needing USB powered fans, please do not suggest fans which use AC power.
Looks like USB PD 3.1 supports 28V
If you need a bigger fan then Geek Air sells a 12 inch camping fan. It has a battery but crucially it has a DC barrel jack for charging. I personally own one so I can tell you the charging brick has a 27V 1A output suspect a 28V input would work just fine. Or you could make your own charging circuit with a buck converter or something.
Its a solid fan. Not sure what your needs are but it’s another option.
I bought it on the jungle website but the model number is CF1SEB if you want to buy it somewhere else.