Built to cool a 19 inch cabinet

[Nuuki9]

Great project!

I'm using it with a 15U cabinet. As its in my home office noise was a factor - I'm using a pair of Noctua NF-A14x25 G2 PWM fans. They're a new model and work great - a bit pricey but as this will be on 24/7 I don't mind.

I made two minor adjustments to the YAML:

• Added a temperature offset entity, to calibrate the DH22 (and included this offset in the tempererature report).
• Added a delta function, to only report a value to HA if there was a change of at least 0.1 degrees.

Also a shout out to @MainMind - I used his 3D printed box design #34 to hold it - glued a couple of magnets to it and it mounts very neatly.

In an ideal world, I would have added a second temperature probe outside to measure ambient tempature. I'd then apply an offset to this (say +2 degrees) to derive a reasonable setpoint that was responsive to room temperature, with an upper and lower limit - say 35 and 25 degrees. That way I could prevent the fan from maxing out constantly when the room temperature went up. I can do all of that with Home Assistant, and trying to route a probe externally would be a pain, so its not a dig deal.

Thanks again - I'll likely build another one for a small form factor gaming PC I keep in the living room - was trying to work out how to keep it out of sight and still cool it, and this will be perfect.

[patrickcollins12]

Nice! Looks tidy. Did you use an Ethernet ESP32? Does the PID controller work for you?

[Nuuki9]

I used an ESP32 D1 Mini as that's what was used in the printed box. Its getting a solid wifi signal and as it doesn't rely on that anyway to work I'm happy with that for now. If I end up making another one sometime I may "upgrade" this one into an ethernet connected version.

The PID controller works great. If I turn the fan off the temps rise pretty fast, and its very cool to see the controller bring it back to the target without any fuss, and hold it there. The twin Noctua's are great - I spent a lot of time looking at 120mm and 140mm options - I almost opted for a single 120mm industrial Noctua - they have great static pressure, which can be useful insomething like a rack, but they're pretty loud, and in the end I went for the consumer models, though two of them. They're almost silent at 80% (given a bit of noise from the equipment anyway) so couldn't ask for more.

One slight niggle - it seems like the low threshold isn't working quite right. I have it set to -0.5, and despite the temp dropping below that, the controller stays in the deadzone. Here's an example from this morning:

At 10:30am it dropped to below 0.5 of the target, but it reported as still in the deadzone. At 10:43 I rebooted the ESP32 and the fan dropped to 0%, causing temperature to rise until the controlled kicked back in once it passed through the upper threshhold. Its not a big issue and I'll do a bit more investigation.