If you have the original case for your Raspberry Pi 5 B and use the active cooler, the cooling will not be efficient unless you remove the top. This is because the hot air will be circulated inside the case.

To get cool air in, you need a plate and fan shroud that allows the fan to draw in air from the top. Since the active cooler is based on a different cooling principle (relying a lot on passive cooling with the big heatsink) the fan is smaller and pushes less air through compared to the fan that originally comes with the case. To help the fan cool more efficiently, I designed a clip-on exhaust port, allowing heat from the heatsink and hot air to be pushed out the back of the case.

Notes:

The clip on can be a little tight to fit, but the parts are flexible enough so it should not be a big problem. Place the front lip first, then one of the sides, push and Bob's your uncle. It makes my Raspberry Pi 5B run at 55-ish degrees C with the active cooler fan running unnoticeable, with the lid on the original case on during normal operation (running DragonOS with Chromium open and updating the system).

The two arrows on the top of the base plate indicate where the clips securing it are, to make it easier to take it off when needed.

I also included the first version without the exhaust if anyone needs it - it will improve cooling, but not as good as the one with exhaust. The active cooler fan does not push as much air as the original fan, and will run much more aggressively to push the hot air around to the bottom of the case.

It will of course cool much better with the top cover off too, as additional air can escape through the GPIO pin cut-out.

Designed with Shapr3D.