Reddit mentions of John Guest Acetal Copolymer Push-To-Connect Tube Fitting, Plug-In 90 Degree Elbow, Tube OD x Stem OD (Pack of 10)

So the basic idea on building a nitro cold brew kegerator is simple. You get either a jockey box or an actual refrigerated kegerator system. The latter is simple and takes most of the work out of the build but also the most expensive. If you go with a jockey box route you can reduce the price from a couple grand to somewhere close to 1/10th the price; if not more depending on how simple or elaborate you want to make it.

If you choose to go with the former option then keep reading, other wise skip the next few paragraphs.

Box
If you want to make it simple there are jockey box kits you can buy that people usually have for tailgate parties. Those have pre-tapped holes and fittings for the beer taps you can swap out for high flow draft taps you want for nitro cold brew, as well as the coils and shank fitting for your product line which ideally would be going to a keg of some sort. (I will be going into how do run a system without a keg IE a simple container/bucket/cambro). And another option is similar to what I have done in the main post which is a beer tower. The one thing that you need to be mindful of for the tower is that you will need to do some fittings to get the beer tower lines to fit to the cooling coils. If the coil have npt threaded fittings this is simple and jsut involves down sizing enough to get a small push in fitting that the beer line can go to. Otherwise if its a naked coil with no fittings this can be simply achieve by getting a food safe line that has a ID that is just barely smaller than the coil OD so that once you fit it on you can tighten to get a airtight seal with a worm clamp.

Lines
To make your life eternally easier buy some no drip DQC's (aka QDC, quick disconnect, quick connects, dripless quick connects, ect) And have that before AND after the coil so that you can take out the coil from the jockey box and clean more efficiently. For the lines doing into the box from the gas and the keg/product container you can do it many ways. As you can see in my pictures there is that weird awkward box with the DQC on them and that was a result of measuring once and cutting before double checking clearance space. The smarter thing to do now that I have worked on this over the year would be to use a bulkhead passthrough fitting/threaded tube that you can anchor down with a lock and nut. From there I would get some kind of threaded adaptor to fit DQC's to them to give it a good clean look for the outside and just a regular line inside to the DQC that feeds into the cold coils. And then DQC's ont he sankey or keg coupler lines as well.

Nitrogen Gas
Now is for the Nitrogen gas. The typical way would be to connect it to either a nitrogen tank or a nitrogen generator system with a regulator to adjust the pressure to push out the cold brew in a keg to dispense the coldbrew through a tap. For this I would recommend using a manifold to split the gas line to push the cold brew in the keg and another to go into the infusion system I will elaborate on later. Each of the output from the manifold should have a shut off valve and attach air quick connects to them so that you can close off lines you are not using or dont have yet for easy expansion. If you are using a sankey keg or a more typical standard keg coupler I recommend attaching air quick connects to the lines for clean and quick attachments to the box.

No Keg method
For a system that is not used in a keg you would need some kind of pump system to push the cold brew through the system when you pull down the tap. For this you will want a pump with a pressure switch like a flojet. I think the best option would be the flojet bevjet compact as it is sold options for what fittings you want in our case push in fittings. You can then just simply put your line for the bevjet input into the container and let it sit in the bottom. Or you can modify your container by dirlling out a hole near the base and fitting a right angle push in stem fitting inside of it so that you can syphon out as much of the cold brew and not waste it(noone lieks to waste good cold brew). From there you follow the same method and fit the cold brew to a DQC to the in line from the Bevjet

Nitro Infusion System
Now this is the meat aand bones of the reason why I made this post. The nitro infusion system. You can go out and spend $600~800 for a completed looking box that you attached to your system and call it a day. But you can also just buy 4 to 5 fittings to do the exact same thing. First the required ones will be an (inline speed control valve)[https://www.grainger.com/product/SMC-In-Line-Speed-Control-Valve-4DGV3?cm_sp=Home-_-MyPurchasedProducts-_-4DGV3&cm_vc=HPMPPZ], T/Y splitter fitting, and 2 (liquid check valve fittings)[https://www.grainger.com/product/JOHN-GUEST-Check-Valve-2JFY8?cm_sp=Home-_-MyPurchasedProducts-_-2JFY8&cm_vc=HPMPPZ]

Arrange them like so:

Column A | Column B | Column C | Column D | Column E
---------|----------|----------|----------|----------
Line out|<<<|T/Y Splitter|<<<|Check Valve
| |^| |
| |Check Valve|<<<|Control Valve

This would be located inside of the box and the smart location to place it would be in between the output of the cold coil and the input of the beer tower/spout.
Side note I forgot to mention you need to run a line of nitrogen gas into the box so be creative on how you want to do it I've explained how to get the cold brew in here so its simple from the manifold that the nitrogen gas spits from the outside.

And then you just adjust the gas with the speed control valve to get a nice creamy texture for the cold brew