Custom passive PC cooling (part 2)
Here is the continuation of the story with passive cooling for PC. Yes, it’s been a long time since the first part and many different concepts have been covered. The optimal option in my case looks like this:
And now let’s analyze it in more detail and consider how I came to it.
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It is better to have the radiator on top of all the components, so that the air draft cools the components even before the main heating.
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Convenient location of components for connecting them with heat pipes and reducing their bends.
But the most important thing here is the radiator itself. Previously, I wanted to cast it from aluminum (you can do it that way), but I liked the option of a prefabricated radiator from aluminum sheets more. Yes, it will take a lot of thermal paste to connect them all, but I think it will show the casting flaws better.
The dimensions were chosen by the power selection method (more on that later), and we should have three main parts:
The ratio of their sizes was selected by selection: the blue part is for the CPU, the orange part is for the GPU, and the center is green. The empty space between them is not empty either – there will be heat pipes, and they will be compressed between them. Then the heat will be transferred better, for example, if the load is only on the CPU or only on the GPU.
Inside, I plan to place all the elements like this:
It is better to completely remove the case from the power supply unit. Perhaps there will be two power supplies to eliminate the fan in them and make them work almost without load, or buy one expensive power supply at once with passive cooling.
The height of the radiator was also selected by the selection method, like all sizes, the best for this power (120W CPU + 220W GPU).
The thickness of the sheets is 3 mm, the distance and aluminum spacers between the sheets are 6 mm (excluding thermal paste). The height of 24 cm is actually excessive, as the tests showed. It is better to increase the length (add more sheets) if you need a stronger iron.
Here are the tests themselves. In fact, I made over 20 different combinations of radiator sizes and shapes. Taking into account that in 3600 seconds (1 hour) the maximum temperature of the radiator was 51 °C, it is possible to add another 10 °C to the loss in heat pipes, thermal paste and all connections in relation to the temperature of the chips, and also add heating of the air in the room in the summer to 30 ° C (tests were at 20 ° C ambient). This gives a maximum temperature of 71 ° C, which, in my opinion, is an excellent result.
By the way, the radiator dimensions are slightly different on the renderings, not the same as on the screenshots with calculations. I did not save everything, here are the dimensions from the calculations:
And here was supposed to be a part of the article with the compilation of all this, but so much time has passed that I decided to collect for even more powerful iron. Yes, you could increase the size of this heatsink, but I’m looking askance at the RTX 5090, which is rumored to draw 600W. This is almost 3 times more, and the radiator is much larger. It will be difficult to find heat pipes of this length, and the mass will be very significant.
There is another solution for such capacities. I haven’t decided yet, but there is an option from the first part: you can simply hide the entire filling behind the heating radiator and use water blocks. Yes, it sounds like a crutch, but there the power reserves will be much larger, and the noise of the pump is almost inaudible in some manufacturers. If someone presents old cast-iron batteries, it will not be so “collective farm”, there are more beautiful options, including dark colors, for example:
However, there are many different designs. The only distance to the wall will be a little more than usual. I think the entire filling can be pressed up to 7 cm thick.
At the moment I’m using a TV instead of a monitor and I think it would be quite possible to fit a heating radiator and all the stuffing behind it. So, there are many options for solving this problem.
If anyone has ideas, suggestions or criticism, I’m waiting for you in the comments.