Project idea: Mutli-air-compressor air controller

[rquackenbush]

I’m interested in building an open-source controller that coordinates multiple air compressors.

Why?

• I’m a nerd. I like embedded control systems.
• Controlling multiple air compressors appears to be deceptively difficult to do well.
• I want more CFM in my shop (I currently have one single-stage compressor on a 60 gallon tank). It technically keeps up with my plasma cutter, but I’d like more headroom.
• I like the idea of multiple compressors rather than one single point of failure.

Disclaimers:

• In my case, it would be waaay cheaper to just buy a bigger compressor.
• There are commercial versions available (though they’re ****** expensive).
• I’m not a compressed air expert. Like at all.

Goals:

• Integrate a base load / peak load option where at least one compressor is run via a VFD to allow for dynamic load.
• Support an optional air flow sensor.
• Support multiple configurations:
  • One centralized compressor bank
  • Distributed compressors for large buildings.
• Integration with:
  • Home Assistant (for residential setups)
  • OPC (for industrial applications)

Would anyone be interested in a system like this?

 

[cvairwerks]

Really just need a lead-lag controller and some check valves... or you offset the cut in and cut out pressures between the compressors.

We run an automated compressor control system at work, but then we have probably a dozen or more 500+ SCFM screw units, a couple hundred thousand gallons of storage and more than 100 miles of 1/2" to 12" air piping in the facility. I haven't been in the tank room for years, but it used to look like we had 8 or 10 railcars standing on end for air storage. Used to have a pair of CP 24" diameter single cylinder compressors for pressure boosting between a couple of the hangars I worked in. Long gone now and the screws cover it all.

 

[GeoBruin]

I’m interested in building an open-source controller that coordinates multiple air compressors.

Why?

• I’m a nerd. I like embedded control systems.
• Controlling multiple air compressors appears to be deceptively difficult to do well.
• I want more CFM in my shop (I currently have one single-stage compressor on a 60 gallon tank). It technically keeps up with my plasma cutter, but I’d like more headroom.
• I like the idea of multiple compressors rather than one single point of failure.

Disclaimers:

• In my case, it would be waaay cheaper to just buy a bigger compressor.
• There are commercial versions available (though they’re ****** expensive).
• I’m not a compressed air expert. Like at all.

Goals:

• Integrate a base load / peak load option where at least one compressor is run via a VFD to allow for dynamic load.
• Support an optional air flow sensor.
• Support multiple configurations:
  • One centralized compressor bank
  • Distributed compressors for large buildings.
• Integration with:
  • Home Assistant (for residential setups)
  • OPC (for industrial applications)

Would anyone be interested in a system like this?

I'm well documented on this forum in favor of "distributed" compressor setups. Lots of members here need a little more air in "peak" scenarios, but otherwise don't need the expense/space/power consumption of a giant compressor. Some do, and they're very vocal about it, but many don't. I think it's a great idea. We get the question once a month "how do I hook up these compressors in tandem" and the answer always depends on the compressors involved, the fittings available, the demand, etc. A simple way to hook up two or more compressors and govern how and when they run to meet peak and base air demand sounds great.

Let us know how it comes along

 

[Lassen Forge]

I ended up with a pair of matching "double hot dog" mini compressors (I think they were Da Fault, er, DeWalt) - I siamesed them together, kept their controls separate, and I was really happy because they were just off enough one (left) would fire off first, the other (right) would come on about 7 PSI lower.... Didn't overload the circuits, and would keep me going for another 30 seconds.

Was it ideal? Not even. But it allowed me to run a lot of air stuff I wouldn't have been able to otherwise.

 

[willf650]

I’m interested in building an open-source controller that coordinates multiple air compressors.

Why?

• I’m a nerd. I like embedded control systems.
• Controlling multiple air compressors appears to be deceptively difficult to do well.
• I want more CFM in my shop (I currently have one single-stage compressor on a 60 gallon tank). It technically keeps up with my plasma cutter, but I’d like more headroom.
• I like the idea of multiple compressors rather than one single point of failure.

Disclaimers:

• In my case, it would be waaay cheaper to just buy a bigger compressor.
• There are commercial versions available (though they’re ****** expensive).
• I’m not a compressed air expert. Like at all.

Goals:

• Integrate a base load / peak load option where at least one compressor is run via a VFD to allow for dynamic load.
• Support an optional air flow sensor.
• Support multiple configurations:
  • One centralized compressor bank
  • Distributed compressors for large buildings.
• Integration with:
  • Home Assistant (for residential setups)
  • OPC (for industrial applications)

Would anyone be interested in a system like this?

No

 

[W-Cummins]

OK, I will will play.... I have been thinking about a similar system, but to control my one compressor. I suggest that you start with controlling a single compressor with a vfd and if you can get that to run it will be easy to expand it to control multiple compressors. I recommend using an esp32 based controller like the one I made for my dust collector.

 

[engineer2]

I designed and built a simple 2 compressor control system for our shop over 20 years ago that they still use today.
A few features:
Alternating relay so the compressors even out run-time hours.
Digital pressure gauge with alarm contacts to determine cut-in and cut-out pressures. Wired in parallel with the compressor pressure switches for a back up. Gauge set points were a bit below the compressor cut in points.
Pressure regulator to run plant air at around 120 psig.
Switches to go to a single compressor if one is down for maintenance.
Hour meters and run indicator lights for each compressor.
Meters to display amp draw for each one. This once helped diagnose a compressor motor going bad.
Refrigerated air dryer.

Planned but never implemented:
Upgrade power to the compressor room and crosswire the alternating relay so it can run both compressors if demand gets too high. In practice, we never had the demand.
Install timers so the system would only run during operating hours, but operating hours could vary. The plant guys just leave it on all the time.
Bluetooth to transmit system info to computers in the plant. Would have required a bit of customization and writing an app.

 

[Zewnten]

I prefer KISS designs and implementation personally. But if its fun to you have at it, document it, and post the build. Then let everyone tell you how you did it wrong.

 

[American Locomotive]

i like the idea, but I just question the utility with just two compressors. This can easily be done via. mechanical means.
Tie the tanks together, have a regulator set to 100 psi. compressor 1 has cut-in/cut-out of 145/175 and compressor 2 is 120/150

 

[theoldwizard1]

K.I.S.S. Just buy a bigger compressor.

OR

Don't overthink it. Buy a second compressor. Plumb the air lines together. When you need more air (CFM), turn on the second compressor. Alternate which one you start first daily.

 

[Shoreline_]

Before the day of comm buses between controllers we used to put these crazy compressor controllers on the wall. They could control up to 4 compressors. It worked good with variable capacity compressors too (modulating inlet or variable displacement air ends)