3 ms·

It's a lot easier to optimise your phase change fluid for a temperature range than to add another constraint to chip design. Anyway, apparently fluid in heat p

by ajb 1y ago

It's a lot easier to optimise your phase change fluid for a temperature range than to add another constraint to chip design. Anyway, apparently fluid in heat pipes work at a range of temperatures not just at the exact temperature of phase change What I always wondered is why we didn't get flexible heat pipes that plug directly into server boards, leading to some centralised heat exchanger or cooling tower, rather using the air as a transfer medium

Retric 1y ago
> plug directly into server boards Because traditional water cooling works better, and air is cheap.
Moto7451 1y ago
Heat pipes have a vacuum so phase change happens at lower temperatures than normal Earth atmosphere. This essentially is how you do what you’ve proposed without having the CPU makers change their designs to run hotter. If you boil water at low pressure and 30C you have the same net effect as boiling itself uses huge amounts of heat energy compared to raising the temperature of water one degree. This is the same energy at any temperature level. On flexibility I think it’s just that vacuum and the wicking structure that limits the materials. I’m not a material science expert by any means but I have to imagine someone has worked on this.
- hinkley 1y ago
  We don’t bond heat plates to the top of CPUs due to the coefficient of thrermal expansion right? Isn’t that why we need paste? Because of CoTE was a non issue I would think we could dig heat dissipation channels into the top of chips, maybe Serpinski gasket style. A little proper lapping and you’d get an airtight seal with the heat sink.
  - bobmcnamara 1y ago
    CoTE between nickel plater copper integrated heat spreaders and copper heat pipes can be a non-issue, especially over such a small area. Increasing the effective surface area is an interesting idea, though minimizing the seam thickness also works to reduce the thermal resistance of the joint, and seems to be more common.

by ajb 1y ago

Retric 1y ago

> plug directly into server boards Because traditional water cooling works better, and air is cheap.

Moto7451 1y ago

Heat pipes have a vacuum so phase change happens at lower temperatures than normal Earth atmosphere. This essentially is how you do what you’ve proposed without having the CPU makers change their designs to run hotter. If you boil water at low pressure and 30C you have the same net effect as boiling itself uses huge amounts of heat energy compared to raising the temperature of water one degree. This is the same energy at any temperature level. On flexibility I think it’s just that vacuum and the wicking structure that limits the materials. I’m not a material science expert by any means but I have to imagine someone has worked on this.

hinkley 1y ago
We don’t bond heat plates to the top of CPUs due to the coefficient of thrermal expansion right? Isn’t that why we need paste? Because of CoTE was a non issue I would think we could dig heat dissipation channels into the top of chips, maybe Serpinski gasket style. A little proper lapping and you’d get an airtight seal with the heat sink.
- bobmcnamara 1y ago
  CoTE between nickel plater copper integrated heat spreaders and copper heat pipes can be a non-issue, especially over such a small area. Increasing the effective surface area is an interesting idea, though minimizing the seam thickness also works to reduce the thermal resistance of the joint, and seems to be more common.