You actually have many options. 1 being the 120v case fan for a computer, you find them at radio shack. This units are designed for continuous use. Think of server cases, once they are turned on they never are turned off. they are designed to handle high heat as well. servers run hot 130 or so.
2. would be a hvac duct fan. This is what dickey incubators have in them (i'm pretty sure) they are also turn on and leave alone. As a matter of fact, any fan that is is constant use will last many times longer then a fan that stops and goes on a continuous basis.
3. and this one is vague for reasons of avalability but is the best option for set and never touch it again. Would be a brushless fan. Do a search for them on
ebay or google. Most likely you can find one in your local area. Alot of solar projects use them do to the power surges that happen between the solar panels and the storage battery.
4. i personally choose to use low amp motors found at any electronics site. You will have to find a fan shroud to fit the shaft of the little motor but thats not to hard either. don't let the size fool you a 1 1/2" x 1" motor will create a lot of cfms. They usually come in 12 - 18 volts @ like 100ma. Just add a transformer between the fan and the motor and they are cheap and compact. you could build a little resistor pcb to step it down but theres less time in a transformer, you can get them for about 5 bucks at radioshack or other electronics depot.
5. The refrigerator motor is a good idea to but i bet they use alot of power. the armiture of these things are about 2" thick. I personally try to keep the power consumption down to a minimum.
Well hope this helps.
