Question Peltier (TEC) chilled water loop for 10W CPU

[titanmiller]

Okay, so this is a weird one. I'm creating a weatherproof live streaming / time lapse camera with a mini-PC inside an enclosed box. I figured there would be heat issues, but my first attempt didn't include any additional cooling and...as you guessed, the enclosure overheated and the CPU throttled deeply. It was too slow to encode the live stream.

My second attempt at cooling involved a Peltier module cooling the air inside the box. This helped, but ultimately there was too much solar load on the box (even when it's 40-50F outside) and it still overheated. I had to put the 12V DC power supply inside the box which added more heat than the CPU so it was counter productive.

My next phase is to construct a custom water cooling loop using the same Peltier module. My question to you is....do you think I can get by with JUST the Peltier to chill the water or do I need an additional radiator to cool the water?

My plan is to use JUST the Peltier (a 60W module) to cool the 10W heat load of the CPU and not have any water to air radiator. Do you think the 10W heat load will overwhelm the Peltier?

I'll keep this thread updated when I construct the water loop. I'm planning on doing that this weekend.

 

[TheELF]

Are you using the CPU for the encoding? If it has quicksync the iGPU will do it with much less power.
Won't the liquid in the water cooler also heat up from the sun?

Maybe if you list all the things you need from the setup people can come up with alternatives that don't heat up as much.
I mean for example you can get a camera that outputs in a usable format instead of having to convert it.

 

[titanmiller]

Are you using the CPU for the encoding? If it has quicksync the iGPU will do it with much less power.
Won't the liquid in the water cooler also heat up from the sun?

Maybe if you list all the things you need from the setup people can come up with alternatives that don't heat up as much.
I mean for example you can get a camera that outputs in a usable format instead of having to convert it.

I'm using the GPU for 1080p (wish I could do 1440p, but the integrated Intel GPU is too slow). According to CoreTemp, the whole package does 10W, but then degrades as the temps get to about 84C.

The big heatsink on the outside is on the hot side of the Peltier. If it's in direct sunlight I imagine I'll have issues....it's been a fun project regardless. I've never messed with Peltiers or water cooling loops, so the education has been a lot of fun.

 

[titanmiller]

Okay...so I spent pretty much all day working on the custom water cooling loop with the Peltier cooler and it actually works. CPU temps are about 30C with a 100% load (10 Watt). The temps used to shoot up to 85C and then the CPU/GPU would throttle and the performance would decay to the point of being unusable.

I used a 20x20mm copper heat spreader directly on the CPU die and then a 40x40mm aluminum water block. The copper heat spreader was needed to raise the water block because there were adjacent components slightly higher than the CPU die.

I'm really happy with how the water block on the computer came out.

I can now do live 1440p streaming video + a 4k still camera for a time lapse project. The GPU only goes to about 65% load.

I actually have the Peltier and water pump under Volted so they are using about 43W instead of the rated 60W for the Peltier. That seems to be enough and I know efficiency tanks as you increase the Voltage.

 

[DrMrLordX]

Nice. It's good to see someone get use out of a TEC. I would have said, use a rad. Hope it works outdoors!

 

[titanmiller]

So far, so good. I've had it in direct sunlight in about 75F ambient temps and the core hasn't gone higher than about 50C. I think I have enough headroom for summer weather.

This weekend's project is to install an optical window for the camera. The plastic front is too scratched to get a good image.

 

[titanmiller]

Nice. It's good to see someone get use out of a TEC. I would have said, use a rad. Hope it works outdoors!

I'm not sure if a radiator would have worked for me or not. I think the ability to go below ambient is needed for this in order to keep the CPU from deeply throttling. It often gets to 95F here in the summer.

 

[DrMrLordX]

I'm not sure if a radiator would have worked for me or not. I think the ability to go below ambient is needed for this in order to keep the CPU from deeply throttling. It often gets to 95F here in the summer.

If the package size had to be kept small, a rad might not have worked. I've only ever seen massive 200W+ installs of TECs that put out insane heat and require lots of radiator capacity. TECs are usually much better for low power applications. So it's nice to see one working for once.

 

[titanmiller]

My only real problem is that my stupid vinyl tubes are kinked and reducing the flow of fluid.

 

[DrMrLordX]

My only real problem is that my stupid vinyl tubes are kinked and reducing the flow of fluid.

Vinyl tubes kind of suck. You may be able to get some black rubber tubing. I use it in my wc setup and it's great. It's non-reactive so you can use any coolant you want (so long as it doesn't damage other elements of your loop) and it's very flexible.

 

[aigomorla]

Vinyl tubes kind of suck. You may be able to get some black rubber tubing. I use it in my wc setup and it's great. It's non-reactive so you can use any coolant you want (so long as it doesn't damage other elements of your loop) and it's very flexible.

The name of the tubing is called Norprene.

TYGON® Norprene® Tubing

Browse TYGON® Norprene® Tubing available at thyssenkrupp Engineered Plastics. Our company’s nationwide logistics system allows next-day delivery to the majority of customers in North America.

www.thyssenkrupp-materials-na.com

It has a lot of issues i do not like, example is fine black particulate matter sometimes.
Id honestly rather use Rigid Piping now, as its much less porous, meaning less top off's, and 0 plasticizer which means u can have clear piping and not fear that dreaded cloudy tubing we used to get.


OP:
Also i don't know how practical your doing this?
Meaning, i don't know where your line in (fun / in field) is.
TEC's are so far deep in the Fun line, that unless its specific to applications there is no way you can use them "in field" effectively.

 

[titanmiller]

The name of the tubing is called Norprene.

TYGON® Norprene® Tubing

Browse TYGON® Norprene® Tubing available at thyssenkrupp Engineered Plastics. Our company’s nationwide logistics system allows next-day delivery to the majority of customers in North America.

www.thyssenkrupp-materials-na.com

It has a lot of issues i do not like, example is fine black particulate matter sometimes.
Id honestly rather use Rigid Piping now, as its much less porous, meaning less top off's, and 0 plasticizer which means u can have clear piping and not fear that dreaded cloudy tubing we used to get.


OP:
Also i don't know how practical your doing this?
Meaning, i don't know where your line in (fun / in field) is.
TEC's are so far deep in the Fun line, that unless its specific to applications there is no way you can use them "in field" effectively.

This was part fun, part field. I could have done a straight water loop with a radiator, but I really think I need sub-ambient cooling to keep the CPU/GPU from throttling so much that it can't perform its function.
It gets up to 95-100F here in the summer and since this is outside it is baking in the sun. The Peltier was my solution to both extract heat and lower temps below ambient. It does suck about 40-45W of power for the TEC (it's a 60W TEC, but I'm running it on about 10V).

If I could do it over again, I think I'd use a water loop and eliminate the live camera that requires the high performance and just have a 4k time-lapse camera...60 seconds is plenty of time to process/upload the image even if the CPU is deeply throttled.

Here's the live cam....a view of nothing significant:

 

[aigomorla]

I think it might be a better solution to just air cool the unit then, and run the TEC setup like how you find them on one of them tiny beer can fridge.

There would be less parts prone to fail, and im not really confident on your choice on that tiny pump.

 

[titanmiller]

I think it might be a better solution to just air cool the unit then, and run the TEC setup like how you find them on one of them tiny beer can fridge.

There would be less parts prone to fail, and im not really confident on your choice on that tiny pump.

That's what I had originally. It didn't work. There was too much solar load warming the air inside the box. The 12V power supply for the TEC was adding a lot of heat too. Maybe it could have worked if I built it inside an insulated box or something.

That was the best/cheapest pump solution I could find. I was hoping to have it inside the box, but the packaging was too tight to make it work.

Yes, I realize this is a silly project in its end state.

Here is a picture of the original TEC air cooling setup.

 

[DrMrLordX]

The name of the tubing is called Norprene.

TYGON® Norprene® Tubing

Browse TYGON® Norprene® Tubing available at thyssenkrupp Engineered Plastics. Our company’s nationwide logistics system allows next-day delivery to the majority of customers in North America.

www.thyssenkrupp-materials-na.com

It has a lot of issues i do not like, example is fine black particulate matter sometimes.
Id honestly rather use Rigid Piping now, as its much less porous, meaning less top off's, and 0 plasticizer which means u can have clear piping and not fear that dreaded cloudy tubing we used to get.

Yup, that's the stuff! I haven't had any particulate issues and haven't needed a top-off in nearly four years of the loop operating with that tubing. I'm very happy with it.