Before starting to build the vortex cooler please keep in mind you will need an air compressor capable of delivering 4 to 5 bar.
Print the parts. The Vortex_generator.stl part will need a little bit of support to be printed but then is easy to remove support material. Sandpaper carefully especially the vortex generator. This is the place where the compressed air enters tangentialy trough the 4 chanells and vortex is created.
The hot end part is comprised from two parts which needs to be glued together. I used Bison two parts epoxy glue which sets in 5 minutes and is very strong. Here you need to accomodate and M3 nut BEFORE glueing. Then drill a small hole in to the cone you will find in part Hot_End_1.stl and glue it to an M3 bolt already screwed in the coresponding nut. Then you can glue the parts together. Screwing or un-screwing will set the final temperature at the both ends. As a general rule, if less air will escape at the hot end, cooler the air will be at the cool end oriffice.
The cone at the hot end can be manufactured from any other material. The cone supplied in the stl file is pretty small and may not keep good shape during printing.
Also you will need some rubber gasket when joining the vortex generator and the vortex generator lid. Use 5xM3 nuts and bolts to secure the parts.
For the vortex tube I am using brass tube. Aluminium is ok too. The vortex tube dimensions: 8mmOD X 6mmID X 180mm. However the tube lenght shoud be anything between 20 < Lenght/Inner diameter < 55. Please experiment as this ratios are very important for cooling efficiency. Also the cold end oriffice which is found in the vortex generator should be something around 3mm. Again please experiment.
You can accomodate some kind of metalic tube at the cold end to attach a hose duct. The hose duct should came close to the chocolate printing nozzle so the cool air can spread across the printed layer.