An unusual query perhaps: I have started using an Akasa Aries
laptop cooler -- a simple aluminium laptop stand with an 8cm fan attached, powered by USB.
The stand is fine, and the simple mechanism of a slab of aluminium and space under the laptop does aid cooling. But the problem is that the stock fan is noisy. So I'm looking for advice on a replacement. The main issue is that it has to be happy and effective working at 5v (online tutorials suggest that adapting a 3-pin case fan to USB is a straightforward task).
The existing fan is 15mm deep, which is also fairly limiting. It's possible I could vary the depth (and even have a fan larger than 8cm?), if I'm willing to forego the "safety" element of the enclosure which surrounds the fan (the main risk would be getting my trousers entangled in the fan if it's on my lap -- as the pictures on the link illustrate, there is no cover on the underside of the cooler, just an enclosure for the fan).
So to summarize, I am ideally looking for a silent but powerful 80x80x15 fan that's effective working on 5v. Any suggestions welcome.
EDIT: I've just done a closer analysis of the unit, and I won't be able to use a bigger or deeper fan -- I'm stuck with 80x80x15mm.