It seems it is not only possible, but actually pretty easy to use compressed air for part cooling. The TPU i am currently using quite a lot needs to be cooled after printing if you have small parts. The cone in the image is 40mm high and has a diameter of 2mm at the top. Without part cooling it would be an abstract sculpture, with it is pretty much perfect.
Please excuse the rubbish sound in the video that shows the part cooler in action.
Looks amazing. How would you say it compares to fan cooling? I’m mostly interested in the zero spin up time being eliminated. 
Since i haven’t used fan cooling very much, i print mostly ABS, i can’t really compare. What i can say is that it is both smaller and lighter than any fan setup i know of.
@Bjorn_Marl Nice! Do you have to have a large compressor? I see you are cooling the hotend, as well. Also, do you have any variability in the parts cooling output?
Are you experimenting with the aquarium bubbler for an air source? That’s something I’ve been meaning to try for a while.
@Stephen_Baird I don’t see an aquarium bubbler pushing enough air. I would use a compressed airtank with on demand compressor.
At first i thought i would need a compressor as well, but it turned out a medium sized “bubbler” is enough, however in this setup i use two smaller ones for the hotends and a sightly bigger one for the part cooler. I already ordered a fairly big one to replace them all. I actually think it might be to big, but i will see next week.
As for controlling the output, i plan to add a solenoid to switch it on and off. To get fine control an adjustable valve should do the trick.
@Kura_kuea I wondered about that too, but the CFM rating of the ones I looked at seemed good enough, and unlike fans the back pressure of ducting shouldn’t reduce usable airflow so badly.
@Stephen_Baird the backpressure was my main concern as well, it turned out to be no issue at all. In my next extruder i designed the air channel into the extruder. It makes it even more compact than the current prototype.
are you planing on publish the parts+instructions+compressor models?
I’m very much interested on your solution, but I lack the knownledge about compressor setup!
awesome work!! keep it up!!
The DuoCube will be released under Open Source after i got the second prototype working the way i want it. The extruder will be a part of it. I am currently looking into making an i3 compatible version, i just need to find someone with an i3 and a Merlin who is willing to test it.
I use an aquarium pump and a very focused output, with a large, fixed 120mm fan when needed for the entire print.
It really works well imho and it is much smaller and lighter than the usual moving fan.
I tried multiple pumps and the only drawback imho is I can’t tune the throughput as easily as with PWM’ed fans. Well I could add a servo to pinch the latex tube 
@Jeremie_Francois Thanks lots man!! great info for a “compressor” newbie like me!! Im definetely ordering a pump to try this out… I just hate the Fans hanging on the extruder!!
@Roberto_Hradec I am glad if it helps! BTW I read somewhere that someone used a piece of telescopic antenna for the air nozzle (less conductive than copper = a good thing).
If you use a silicone sleave it is no problem to get rather close with printed parts.
@Bjorn_Marl good idea! In addition is will not be knocked aside on protruding blobs of printed material…
@Jeremie_Francois I actually meant that you need to use a sleave on the heater block, but your idea makes a lot of sense as well 
@Bjorn_Marl lol, so it ends with yet another idea, thanks anyway And yes, I am also an early advocate regarding hot end isolation (it looks like I am promoting my old blog http://www.tridimake.com/2014/03/thoughts-and-hints-around-hot-ends.html, sorry)
@Jeremie_Francois interesting blog. Different to you i went the PEEK route and with compressed air cooling my Merlin hotend will print at 260c without problems.
