Watercooling for the Pi!

[SiliconWizard]

https://www.seeedstudio.com/High-Performance-Liquid-Cooler-for-Raspberry-Pi-5-p-5854.html

 

[brucehoult]

5 GHz or bust.

[DiTBho]

I would need something similar Liquid-Cooler made by seeedstudio to raise the clock of a particularly unlucky mips32r2/be SoC by 120Mhz.

It's a 10 years old board. The SoC is mounted on the RS/Pro, which has several problems.
e.g. the RTC CS shared with the serial (high = RTC enable, low = uart enable), a very stupid thing, a 1GBps network port on the SoC side multiplexed across 4 physical ports, and, even worse, the PCI does not implement the PCI_IO, the hw is missing, and the default thermal dissipation part is a copper sheet that does not allow you to push beyond 680Mhz a SoC that could (from the datasheet) easily reach 800Mhz!

+120Mhz on a RISC pipelined CPU can make a huge difference!

It's full of flaws, but I love that SBC because of how, talking about things made in 2014, small it is and stable.
The default case is also very cool, they made a version with mini rack handles, which I love!
Unfortunately there is no space inside the plastic case, and since the case is plastic, a liquid device that carries the heat out would be ideal, even if in this case it is abundantly oversized.

I could hack the PLL module and implement a "turbo mode" that increases the clock by 120Mhz, running the water pump at full capacity.
That's because another nice thing about that board is that it has a 48V POE power supply, not bad for solar charging kits designed for sailing.

We will see 

[radiolistener]

To heat the water in this kettle, it looks like it will need to buy also a heater - the Raspberry Pi clearly can't handle it! 

[Bryn]

Okay, that looks pretty stupid

Whoever thought that was a good idea needs to have their head checked.

[5U4GB]

https://www.seeedstudio.com/High-Performance-Liquid-Cooler-for-Raspberry-Pi-5-p-5854.html

 

Next up, a turbocharger for the Fiat 500.

[brucehoult]

https://www.seeedstudio.com/High-Performance-Liquid-Cooler-for-Raspberry-Pi-5-p-5854.html

 

Next up, a turbocharger for the Fiat 500.

In fact my sister, who is a nurse in Wellington, has a tiny Fiat which I think is a "500". It has a turbo. Is it a 3 cylinder 1000cc? Something like that. I've ridden in it a few times but haven't driven it. It vibrates a bit at low RPM but goes very well with a few revs and feels pretty sporty going over the hill to Johnsonville from Ohariu valley where she lives.

[DiTBho]

Okay, that looks pretty stupid

It's idiotic for RPI.
However, it makes sense for the tini project I talked about above.

[SiliconWizard]

https://www.seeedstudio.com/High-Performance-Liquid-Cooler-for-Raspberry-Pi-5-p-5854.html

 

Next up, a turbocharger for the Fiat 500.

Why not.
 

[5U4GB]

In fact my sister, who is a nurse in Wellington, has a tiny Fiat which I think is a "500". It has a turbo. Is it a 3 cylinder 1000cc? Something like that. I've ridden in it a few times but haven't driven it. It vibrates a bit at low RPM but goes very well with a few revs and feels pretty sporty going over the hill to Johnsonville from Ohariu valley where she lives.

If it's a 1000cc engine then it'd be a Fiat 1000, not a Fiat 500 :-).  This is a 2-cylinder 13hp engine that's truly gutless (it's about the same as a 100-125cc modern bike engine develops), my parents had an early-60s Fiat 500 and every time it went up a hill of any size I had to get out and walk because it couldn't manage the climb with three people in it.  Or at least it could but it really struggled.

[5U4GB]

Next up, a turbocharger for the Fiat 500.

Why not.
 

Well, if you really tried you might be able to get as much as 15hp out of it that way.

(When I referred to the Fiat 500 I meant the classic 1957 to early-70s models, not the post-2000 vehicle with nothing in common but the name).

[brucehoult]

In fact my sister, who is a nurse in Wellington, has a tiny Fiat which I think is a "500". It has a turbo. Is it a 3 cylinder 1000cc? Something like that. I've ridden in it a few times but haven't driven it. It vibrates a bit at low RPM but goes very well with a few revs and feels pretty sporty going over the hill to Johnsonville from Ohariu valley where she lives.

If it's a 1000cc engine then it'd be a Fiat 1000, not a Fiat 500 :-).  This is a 2-cylinder 13hp engine that's truly gutless (it's about the same as a 100-125cc modern bike engine develops), my parents had an early-60s Fiat 500 and every time it went up a hill of any size I had to get out and walk because it couldn't manage the climb with three people in it.  Or at least it could but it really struggled.

That was the 1960s. I'm well familiar those those. One teacher at my high school had one. A surprisingly small group of us picked it up one day and put it inside a (no entrance) fence around a tree.

I quote: "Fiat has offered a wide range of engines in the 500 since 2008, including a 69hp 1.2-litre petrol, a 100hp 1.4-litre petrol and an unusual 85hp 0.9-litre twin-cylinder."

Come to think of it, I'm pretty sure my sister's car must be the 900cc twin cylinder, turbo'd. Internet says the NA version is 85 HP and the turbo 105 HP.

[brucehoult]

(When I referred to the Fiat 500 I meant the classic 1957 to early-70s models, not the post-2000 vehicle with nothing in common but the name).

Not the only example.

Even current and original Corolla or Civic are hugely different in size.

[Nominal Animal]

I would need something similar Liquid-Cooler made by seeedstudio to raise the clock of a particularly unlucky mips32r2/be SoC by 120Mhz.

Instead of watercooling, I would recommend considering having a heatsink base/lid milled out of solid aluminium billet, with "pedestals" reaching to the chips to be cooled.  It can be a bit tricky, so designing the exact shape via 3D printing prototypes iteratively will work best (don't need to be dense at all either, just precisely correct size, so well-calibrated printer is needed).

Many SBCs like Odroid M1 are designed to be directly interfaced to a large heatsink, with only the most heat-generating components on one side of the PCB.  I first saw this with an Odroid HC1 I bought, which has a very small PCB but with a large enough heatsink to hold a 3.5" drive, too.

For the other type of SBCs I have, I like mounting them upside down into a Hammond die-cast aluminium enclosure, with the SBC on the lid, with enough room inside the enclosure for the connectors to be inside the enclosure and only the cables to pass through at the seam between the lid and the box (through U-shaped grooves with grommets on the box side).

I even have an early model SmoothieBoard in a Hammond 1590XX with a shaped 5mm thick heatsink bar soft-soldered and bolted to the inside of the lid, so that with some non-conductive thermal interface material (silpad) the stepper drivers are heatsinked to the lid through the board.  (It has A4988 drivers built-in, which unfortunately are nowadays much inferior to the Trinamic TMC2100/2130/22xx/516x drivers commonly used in similar controllers: the Trinamic ones are much quieter and smoother.)

The same applies to Raspberry Pi 5.

Edatec ED-Pi5Case-B, sold by Digikey, Mouser, at Aliexpress etc, which maintains CPU temperature below 65°C at ambient 30°C (report at cnx-software.com) while CPU is maxed out. Joy-IT.net has ready-made cases (RB-AlucaseP5-08, -09), using exactly the "pillar" technique I described above, but I haven't seen thermal reports of these; I fully expect them to perform similarly to the Edatec case, +35°C to +40°C CPU temperature over ambient at maxed out CPU load without throttling.  These are all fully passive, so there is no fan noise either.

Because the passive-cooled ED-Pi6Case-B (also called Pi 5 CNC case) can reportedly keep Pi 5 CPU temps below 65°C at ambient 30°C at full load, and you can buy one from Mouser in black or silver for 15€+VAT right now, or for under 25€ including VAT and shipping from Aliexpress, why on earth would you spend 100€ on watercooling?  The only reason I can imagine is the visual appeal, like LED lighting in your desktop computer.  I can imagine someone making a steampunk/alien diorama out of this water cooler setup..

[DiTBho]

Instead of watercooling, I would recommend considering having a heatsink base/lid milled out of solid aluminium billet, with "pedestals" reaching to the chips to be cooled.  It can be a bit tricky, so designing the exact shape via 3D printing prototypes iteratively will work best

the default RS/Pro case is very nice, but there is no extra space inside for a heatsink, fans, or anything else thick enough to cool the SoC.
I'd have to cut a square hole to mount them, and that's not something I'd like to do.
There's just enough room for the heatsink, and there are already holes in the back for two extra antennas (3 holes, but I only need 1 antenna), which I can use to run the small tubes to the radiator.

Code: [Select]

|                    |
|#                  #|
|#soc1          soc2#|
|#                  #|
|                    |

then there is another problem: I have two RS/Pro (they talk over OpenMPI), arranged inside a cubic metal frame, the two motherboards are arranged so that the respective SoCs face each other.

in this case the heat exchangers of the liquid cooling system do not impact the overall design at all, while if I were to use heat sinks + fans, I would have to rethink the entire frame, probably spacing the two motherboards better

[Nominal Animal]

in this case the heat exchangers of the liquid cooling system do not impact the overall design at all, while if I were to use heat sinks + fans, I would have to rethink the entire frame, probably spacing the two motherboards better

Right; I see, yes.

What you need, is a simple water block that fits exactly between the two SoC chips.  Because of symmetries, you can have one milled from aluminium in three parts, forming two symmetrical but separate water blocks, one intake/exhaust (with G1/4 female thread) each. The middle plate is simply a shared baffle/cover, with bolt holes in the corner, plus a through hole for waterflow between the two blocks.  The cross section of the channel should be about 20-30mm² (5mm to 6mm diameter circular area) to maintain the water flow; I'd consider a spiral, with no corners, and the cross-connection with a ramp at the center with a bit of extra volume around it.  Very simple 2D/2.5D milling job with a single cutter, possibly with finishing with ball nose cutter for the center ramp.

If you use G1/4 female threads on the water blocks, you can use a large number of different connectors/fittings and basically connect it to any cooler and pump on the PC market.  The water pressure is quite low, too.

I'm not up to what is available on the market right now, but I'd probably start by looking at Alphacool Eisstation + DC LT 2600 reservoir and pump, an aluminum radiator, and 8/5mm hoses and suitable connectors.  Make sure you don't mix aluminium and copper in the same setup, though –– you need to use brass or aluminium fittings –– as mixing alu and copper can wreak havoc with the coolant fluid.  I would budget about 100€ to 120€ for the off the shelf stuff.  For the custom water block, I'd ask around the local hackerspace, and maybe check out the JLCPCB CNC cost if they do them out of 6061 aluminium.  Note that the contact surfaces are flat, so one can sand them flat on top of large enough mirror and increasing grits of sandpaper.

In any case, making 3D models and 3D printing them on a well-calibrated printer, to find out how it might work, would still be the first phase of the project for me.  I wouldn't buy anything until I had a suitable water block assembly in my mitts.  Using a huge automotive aluminium radiator (passive) would be funny, and should work, but would probably need a custom pump and possibly reservoir.

[radiolistener]

Instead of watercooling, I would recommend considering having a heatsink base/lid milled out of solid aluminium billet, with "pedestals" reaching to the chips to be cooled.

I'm using this one:
https://www.aliexpress.com/item/4001309643679.html

It is very compact and allows for the placement of thermal sticks for all heating components on both sides of the PCB. However, its surface area is somewhat insufficient to keep the temperature below 70 degrees during a stress test running -c 4 for more than one hour. This is for overclocked RPI4 at arm=2100/gpu=700 MHz. For regular tasks, it is more than adequate. With a browser and heavy tasks, its temperature stays within 55-60 degrees.

I also put a large heatsink on top (60x52x40 mm), which helps maintain the temperature below 45 degrees even under heavy load. Additionally, it is fully passive, absolutely silent, and has no additional power consumption.

The only downside is that WiFi signals are reduced by 20 dB, making it unable to receive weak access points. This case has a plastic window near the WiFi antenna, but it is insufficient.

[SiliconWizard]

Unfortunately there is no space inside the plastic case, and since the case is plastic, a liquid device that carries the heat out would be ideal, even if in this case it is abundantly oversized.

I would still recommend going for heatpipes and a fan located further away where there is some room, just like is done on laptops. Liquid cooling is a pain for maintenance (bt, dt).
Problem is finding something that will fit. You can't just cut heatpipes to the length you want. They are not empty. Cutting them would render them completely ineffective.

[shabaz]

Attached photos show an attempt at passive cooling for an older Pi model, in a plastic enclosure (I have not used this Pi in a while so I cannot get any more measurements from it). I only had simple tools, so I couldn't do anything fancy to hold the heat pipe in place, so it was simply glued. At the time, for a basic test, cpuburn was run and the external heatsink got hot, and there wasn't any throttling, at typical ambient room temperature. An even bigger heatsink could be worthwhile. And it was great that no fan was required. The heat pipe was a good problem-solver. The case was watertight for outdoor use (the heatsink was glued to the case, around the hole for the heat pipe).

[DiTBho]

Liquid cooling is a pain for maintenance

Why do you say this?

I recently worked on the Leonardo supercomputer, small consultancy on a software face, not even important, anyway I had the opportunity to see how a supercomputer is made up of several nodes installed in different racks, and how each note can talks to every other node!

Code: [Select]

node[]={ A, B, C, D, E }
link[]=
{
    A-B, A-C, A-D, A-E, // fiber-switch#1, the connection is high0speed, low-latency, unidirectional
    B-A, B-C, B-D, B-E, // fiber-switch#2, "
    C-A, C-B, C-D, C-E, // fiber-switch#3, "
    D-A, D-B, D-C, D-E, // fiber-switch#4, "
    E-A, E-B, E-C, E-D, // fiber-switch#5, ""
}

This thing scares me because I literally go into crisis when I have more than 5 nodes to connect, in the sense that, with hobby technologies .... you only have ethernet switches, and connecting each node with all the other nodes, means creating a bundle of fiber cables on fiber switches that never have enough ports, and in any case you end up with towers of fiber switches that you don't even know where to put ...

That's why we we do not create node-to-node connections of that type, but simply networks and subnets that do their job, cost less, take up less space, cost less, at the compromise of adding a lot of lag due to packet routing

Code: [Select]

Poor-man ethernet 6 ports switch: 5 for nodes + 1 extra port to allows you to route network packets to another group of nodes connected to another switch

switch ---------------
         | | | | |
         | | | | |___A
         | | | |_____B
         | | |_______C
         | |_________D
         |___________E
(dirty cheap, dirty simple)

If you try to realize with hobby/consumer technology the solution used in Leonardo, everything quickly gets out of control ... lucky them that they have dedicated things ... even liquid cooling systems with dedicated rooms, and, inside each node, copper heat exchangers, one for each processor, be it CPU, NPU, GPU, or whatever (from IBM zServer tecnology).

That's amazing! Each heat exchanger has copper pipes, one to let cold water in, one to let hot water out, and all the pipes are collected in special concentrators under the floor, which go directly to the floor below, where there are giant pumps (1.8m tall, taller than me!!!) that bring hot water to huge radiators outside the building.

This stuff works without any problems, and even Google/Switzerland, which I visited, has systems like this.

But, should it be a problem to make something like this small for a simple two node SBCs?
And if yes, what would be the "pain" for a maintenance "poor" man?

[DiTBho]

heatpipes

The heatpipe technology (even with "solid-state cooling fans", which is the near future) is definitely what I would use if this were a final product.
So if I had the budget and know-how of someone who can design and build custom heat shields and headpipes, I would go with this.

Unfortunately I have not, and consider reusing stuff from used laptops... I can tell you from personal experience: I've done it in the past(1), and it was a total nightmare!

(1) I hacked my PowerBook-G3/750@400Mhz, making it G4/7410@550Mhz.
From 7Watt, to 14Watt required a better heatpipe and heat-shield, so ... I started dismantling head pipes from used laptops bought on eBay, with a lot of patience I bent the pipes, but it took several and several attempts both to bend them without strangling or breaking them, and to solder them and to adapt them to the copper heat shield of a different geometry than that of the original pieces from which I had dismantled them.

For the series ... 10 attempts for only 1 satisfactory result.

[beginner_max]

??
Abarth 500? exists already

https://www.seeedstudio.com/High-Performance-Liquid-Cooler-for-Raspberry-Pi-5-p-5854.html

 

Next up, a turbocharger for the Fiat 500.