Ventilation system for PCB suggestions are welcome

Well…, I am very sorry for my diagram below… As it lacks beauty…!! But my efforts are genuine…!!

Basically what i want is :

    1. To provide natural air ventilation
  • If this ventilated case comes in contact with rain or water, It should protect itself from water getting inside and damage my PCB components

I would be very happy to get suggestions over this design… And also have questions :

  • Will my hot air would be dissipate from the above 2 plastic ducts?
  • Will below 2 plastic ducts would suck the fresh normal outside air within in…?

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Image from Original Post so we don’t have to download it. See this Simple Image Guide

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…R

The dimensions of the ducts matter and you have not provided any dimensions on your drawing. Neither have you told us how many watts have to be dissipated or what is the acceptable maximum temperature.

And, as @spycatcher2k has said this is a thermodynamics question - and probably a difficult thermodynamics question.

I suspect the most practical thing is to carry out some experiments.

...R

Your circuit boards will be damaged by HUMIDITY, which is the water in the air you are circulating through the enclosure.

Use conformal coating on the boards. Make an air tight enclosure with dissicant packages. If heat is a problem, use a heat-sink to move the heat outside the enclosure.

Paul

Paul_KD7HB:
Your circuit boards will be damaged by HUMIDITY, which is the water in the air you are circulating through the enclosure.

Use conformal coating on the boards. Make an air tight enclosure with dissicant packages. If heat is a problem, use a heat-sink to move the heat outside the enclosure.

Paul

Thank you so much “Paul”. Yes air tight enclosure with heat sink will be the solution for heat dissipation and conformal coating for humidity… I appreciate you for giving your time and suggestion. And … YES… It helped me dear Paul. Thank you very much

I still favour keeping boxes ventilated and mounted such that water can't get in (or if it does, drains out right away). The heat of the electronics should be enough to keep moisture out - just a few degrees elevation is enough even in times of 100% ambient humidity.

Plus a spray of conformal coating.

I've seen a bit of corrosion on unprotected PCBs after spending a few years outdoors (they still worked fine), not yet on my coated projects but those aren't out there that long yet.