fransurbo

I just bought myself a 400W Peltier, but I'm wondering 'how to use it'.

I don't want to run it at 'full throttle' (I know that a Peltier is most affective when it's running at half the marked wattage - that's what I mean by 'full throttle'). I.e., I have no need to run my CPU at sub-zero temps. +/-5 degrees celcius of ambient is sufficient for me. Then I don't have to isolate the motherboard etc...

Is there any way to control how cold (effective) the Peltier gets. Preferably automatic? It should probably be tied to the OS somehow so it can read/use the CPU/Motherboard temps and ajust accordingly...

zipdogso

Oh dear....this sounds like a "classic" case of running before you can walk, you do realize of course that to run the TEC effectively you are going to need rather more than just a power source ??? depending on whether the 400w your quoting is Pmax or Qcmax at 1/2 power the TEC may not be sufficient for your CPU. What CPU you planning?

For maximim efficiency (sorry...COP.) you look more for 1/7th power. But 1/2 is a fair compromise but the heat pumped will be much smaller also....at 1/2 power, about 45% of Qcmax, if you have good cooling on the hotside. What is the Qcmax of the TEC you have ?

Are you going to run this direct die on the CPU or through a chiller?
If you go direct die the TEC will go sub-ambient causing condensation when you CPU idles and dependant on your overclock may even go sub-zero.

You control the TEC either with a thermostat or a dedicated TEC controller.
To deal with the high current switching without breaking down quickly the thermostat really needs to be one designed for use in heating/cooling systems by that I mean household systems not aquariums !! TEC controllers are expensive from a commercial dealer but I know of a good DIY version that is cheap. As an alternative look through Ultrasonic2 posts or perhaps PM him he knows how to set up a cheapish controller so it works with TEC's.

You need to decide how you want to use the TEC as this will depend on how it's setup, cost of setting up etc.

Livinstrong

I'm not sure thatyou realize that you need a nice watercooling system to cool the peltier.

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zipdogso

It depends...If the TEC is low power or you run it at low power (150w or less) it is quite OK to use a good quality Heatsink and fan arrangement...much like you have on a CPU.

EDIT - Actually in this case it is highly unlikely air will suffice (need to know the CPU TDP.) as for 150w power the Qcmax needs to be about 110w the remainder being the heat actually generated by the TEC.

Livinstrong

As long as it is a 50mm peltier, yea. Like you said in your post, this peltier is sold as 400w, but it might not have a qmax of 400watts

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Ultrasonic2 (muffy)

it wont be a 50x50mm 400watt QMAX cos this does not exist. It'll be aPMAX number as stated before. Those bad E-bay sellers. GRRR

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Ultrasonic2 (muffy)

As a general comment about Air cooled TEC's .. When using a 360 or real 400 Qmax TEC i believe a TEC could reduce temps. But ONLY with low input voltages.. Results could be comparable to a Watercooling only system.

With a watercooled TEC system you'll get much lower temps of course.

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zipdogso

Absolutely....

That's why I said low wattage or run at low input power. If you think about it most stock CPU coolers are rated in the 100w-150w range so using a quality cooler on a Qcmax (small TEC.) or Qc (big TEC undervolted.) of 100w-110w will get good results but obviously water cooled will always be better....same thing with CPU's.

Ultrasonic2 (muffy)

it would have to be a high powered under volted TEC. cause you dont want to add to much more load to the Air cooler so the Large TEC is the only way to go

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wildlaurel

to control the tec power you will have to design a small circuit.. a buck regulator can be used to do the job.. or if you just want two power states (high/low) then a SPDT switch/relay could just work fine..
also if you want it to be automatic then you need a thermal sensor such as LM35 to carry a feedback from cpu block to a microcontroller and in turn the tec power be controlled by the microcontroller..