It’s an ejector – it uses a relatively small amount of high pressure air to entrain a large amount of the ambient air: http://en.wikipedia.org/wiki/Ejector

If it was actually more efficient to pump air this way you’d see aircraft engines like that – which you don’t. Ejectors are notoriously inefficient, but simple with no moving parts in the flow – which is worth the loss in efficiency sometimes, like when mixing hot engine core flow with the cold bypass fan stream in an augmented low bypass turbofan engine: http://en.wikipedia.org/wiki/General_Electric_F110
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4,066,214.PN.&OS=PN/4,066,214&RS=PN/4,066,214

(or when it just looks cool, like this fan – but would you pay $350 for one?)