I set up a 2 tap draft system at a hackerspace that has its own homebrew club. We have a full size fridge, and an air cooled insulated supply and return line to the bar's draft tower. There's enough room to expand to 4 taps. Unfortunately, we're victims of our own success. Anything we brew and put on tap gets guzzled in short order, and we'd like to ration how much gets put out for free public consumption.
We're also a bunch of electronics geeks that like to over-engineer anything we can get our hands on. The idea: Use a Raspberry Pi to control access to the draft system, with a display to show what beers are on tap, and what taps are operational vs. what taps are off limits. Then, have some kind of electrically actuated valves to lock each of the beverage lines.
I'm using 1/4" beverage hose. Has anyone done anything like this? My two concerns:
1. I have heard that a lot of these kinds of valves have small orifices and will cause the beer to foam in the line.
2. The valves themselves will be in the refridgerator. I've seen 24V normally closed solenoid valves, but these take a lot of power. For events, we may want all taps open, and if they're all energized, the solenoids will put out a lot of heat into the fridge. I'm instead thinking about something that has a motor or servo actuator, where opening or closing it takes electricity but leaving it in the open or closed position doesn't.
Any help would be greatly appreciated.