I always prefer blowers vs fans. They are more reliable, silent and put more air. In this case, where you want to blow a tiny area focused on the nozzle, a little air pressure is needed. When I use fans to this same thing a lot more turbulence are created in the air conduct that creates a great resistance for the air to flow, thus the air flow at the nozzle is poor. With a blower things change a lot, a high air pressure zone is created at the end and air doesnt tend to leave the blower at the wrong side (like with a fan happens). So I designed a blower support to be used as layer fan. I designed it robust, modular and simple, to be printed easily, and maybe to be used in other parts of the printer. Also included a support to be screwed to the extruder to attach the blower(s) coming from other of my designs for the L3K. This is a very precise solution, the air blowing is concentrated just into the low level of the nozzle. Do your proof, because the blowing at 100% blower power could be intense for some prints. Printing... No special instructions needed, just use ABS or any high glass transition temperature material. I've got awesome results, better than ever with PLA at 50% power with a standard 50mm blower. Anyway, if you need more, you can even add a optional second blower!!! I can guarantee that the air flow this thingy reaches is way BEYOND the flow achieved with any fan solution I have tried. Last thing: use antirotation washers if you think you need them (although I didn't need them).

See also: http://www.thingiverse.com/thing:993577
TODO: Nothing. Original goal surpassed.

Be careful, dont put it at 100% speed or it will blow away your things from your printer bed :-)
Enjoy!!

UPDATES:
(22-SEP-2015) Added a mirrored anchor to mount a second blower on the right (as requested). Increased lenght of the anchor to the same length as the other things (aesthetical reasons). Updated files according, added a new pic of the dual solution.

(21-SEP-2015) Blower support: added trim for air entry. Anchor: adjusted offset. Warning, build pic is for old version. Will upload new ones when available. Air redirector: Added a wider, smoother, stronger V2 this should improve even more the cooling. Sources: FreeCad sources & pics added.

(18-SEP-2015) Enhanced blower support, redesigned from zero. Pic added.