Using Toy Stirling as a Heatsink on a lowish TDP CPU

[Chance Jackson]

I'm not thermal physics smart, all that jargon goes right over my head that said I'm a computer enthusiast and while wiki-walking (I started on heatpipes) last week I learned about stirlings and thought about their potential applications in PC cooling, while looking into that I discovered MSI had experimented with that in 2008 but never went to market
http://www.dailytech.com/MSI+Showcases+ ... e10918.htm
http://www.youtube.com/watch?v=OqqeR4ZRx6w

Now I'm thinking why not get a toy 250g toy unit like http://www.amazon.com/Sunnytech%C2%AE-T ... p+stirling sit it on an expendable Athlon XP 2500+(45w TDP) and produce some work from that heat?

What I would like to know since I'm physics challenged:
-When the toy turns heat into work how much heat from the base of the toy is consumed/dissipated?
-How many watts could a toy unit handle assuming a room temp of 24c and a maximum allowable processor temp of 70c
-Assuming 180 to 200 rpm how much work is that?
-I understand that work is mechanical energy but how is that measured in this context? Torque? HP?

[Ian S C]

Chance, the little LTD motor would probably run on the heat from a CPU, in the days of CRT screens, some people ran them from the heat from the screen's power supply.
For computer work the Stirling Engine is used in reverse as a cryo-cooler, so it's driven by a small electric motor, a small motor driven like that should, it free air get down to -20*C.
The little LTD would probably run at 100 to 150rpm, and these motors have just enough power to run without any extra load.
Ian S C

[Triangle.Stirling]

Chance Jackson,

I have the exact engine you link to in your post. (however i got it from china --> same engine but cheaper)
When i let it run on hot water, and the water cools down it stops when the temperature difference is 20 degrees celsius. Assuming your room temperature is 20 degrees celsius, it means it only starts at 40 degrees plus.
Look up this page: http://www.instructables.com/id/Stirlin ... velope-on/
This guy purchased said engine, and pushed it to the limits (and beyond) After tweaking it he ran it for 13 hours continuously, then it died.

I read that you assume a room temperature from 24 degrees Celsius. That means the engine will start at >45 degrees Celsius. I think that's a bit late. With a higher precision engine it would be better. You can get engines that run from a difference of 4 degrees Celsius, however they are expensive.

How many watts is hard to say. Never tested the power of the engine. However, it will be far less than 1 Watt i imagine. I wonder how much heat a CPU/GPU produces? I know that my poorly cooled cpu produces a lot of heat, it will go to dangerous values when playing games.
The work that is done is usually measured in watts. Thats how much torque the crankshaft gives, -how much force it costs to stop it-,
multiplied with the speed.

To make a system like MSI work you need to have a more high-tech engine than said engine. I'm just now wondering, how much heat does a cpu/gpu produce? It sure would be very cool to have a cooling system like that! Maybe something to try in the future.
Hope i helped you, feel free to ask any further

[Ian S C]

Chance, to run a hot air engine to cool your computer would not take much more power for the electric motor that the fan used for air cooling the heat sink.
Running the LTD motor from the CPU would be interesting, these motors have been made to run on less than 1*C temperature differential, and motors that run on the heat from the palm of your hand are not uncommon in the world of LTD Stirling Engines.
Ian S C

[Chance Jackson]

Thanks Ian and Triangle for responding

Chance, the little LTD motor would probably run on the heat from a CPU, in the days of CRT screens, some people ran them from the heat from the screen's power supply.
For computer work the Stirling Engine is used in reverse as a cryo-cooler, so it's driven by a small electric motor, a small motor driven like that should, it free air get down to -20*C.
The little LTD would probably run at 100 to 150rpm, and these motors have just enough power to run without any extra load.

so if I put an ltd a top a processor capable of hitting 70C and I tried to hook up a 5v dynamo I wouldn't get much current out of it?

Chance, to run a hot air engine to cool your computer would not take much more power for the electric motor that the fan used for air cooling the heat sink.
Running the LTD motor from the CPU would be interesting, these motors have been made to run on less than 1*C temperature differential, and motors that run on the heat from the palm of your hand are not uncommon in the world of LTD Stirling Engines.
Ian S C

I guess my only real option is to buy it and then try it

Chance Jackson,

I have the exact engine you link to in your post. (however i got it from china --> same engine but cheaper)
When i let it run on hot water, and the water cools down it stops when the temperature difference is 20 degrees celsius. Assuming your room temperature is 20 degrees celsius, it means it only starts at 40 degrees plus.
Look up this page: http://www.instructables.com/id/Stirlin ... velope-on/
This guy purchased said engine, and pushed it to the limits (and beyond) After tweaking it he ran it for 13 hours continuously, then it died.

I read that you assume a room temperature from 24 degrees Celsius. That means the engine will start at >45 degrees Celsius. I think that's a bit late. With a higher precision engine it would be better. You can get engines that run from a difference of 4 degrees Celsius, however they are expensive.

Interesting, how expensive?

How many watts is hard to say. Never tested the power of the engine. However, it will be far less than 1 Watt i imagine. I wonder how much heat a CPU/GPU produces? I know that my poorly cooled cpu produces a lot of heat, it will go to dangerous values when playing games.
The work that is done is usually measured in watts. Thats how much torque the crankshaft gives, -how much force it costs to stop it-,
multiplied with the speed.

To make a system like MSI work you need to have a more high-tech engine than said engine. I'm just now wondering, how much heat does a cpu/gpu produce? It sure would be very cool to have a cooling system like that! Maybe something to try in the future.
Hope i helped you, feel free to ask any further

CPUs/GPUs and most other processors are rated in terms of TDP Thermal Design Power basically how much power they draw and thus needs to be dissipated. modern GPUs produce more heat then contemporary CPUs in the same performance class. Highest end Gpus like the Geforce 780ti and Radeon 290x can be around 300w TDP that's before overclocking!

[Triangle.Stirling]

Chance,

so if I put an ltd a top a processor capable of hitting 70C and I tried to hook up a 5v dynamo I wouldn't get much current out of it?

That's right. The engine hasn't much power, so you can't put much load on it, and wo you won't get a usable amount of power out of it.

I buy stuff from China quite often, and so i bought this engine. You can look it up here:LTD stirling
I'm 100% sure it is the same engine as the amazon listing. People just resell them and make profit. You see them quite often for higher prices.
I buy regularly from this seller, they're thrustworthy.

That's a lot of heat for sure. I'm curious if a stirling engine is able to dissipate that kind of heat, it sure is a nice heat source!
Maybe a thing to consider is, you have to start the engine. A standard engine like the one mentioned above, has to be started with a little push, it won't start from itself.

Regards,

Krijn

[Chance Jackson]

Chance,

so if I put an ltd a top a processor capable of hitting 70C and I tried to hook up a 5v dynamo I wouldn't get much current out of it?

That's right. The engine hasn't much power, so you can't put much load on it, and wo you won't get a usable amount of power out of it.

I buy stuff from China quite often, and so i bought this engine. You can look it up here: LTD stirling engine
I'm 100% sure it is the same engine as the amazon listing. People just resell them and make profit. You see them quite often for higher prices.
I buy regularly from this seller, they're thrustworthy.

That's a lot of heat for sure. I'm curious if a stirling engine is able to dissipate that kind of heat, it sure is a nice heat source!
Maybe a thing to consider is, you have to start the engine. A standard engine like the one mentioned above, has to be started with a little push, it won't start from itself.

Regards,

Krijn

bummer I thought ltds only needed a heat source to get going.

do you have a link to the chinese seller?

[Triangle.Stirling]

Hi,

Sorry, I made a mistake with copying the URL. I updated my previous post, so it's now correct there. You could also try searching Ebay, there are more Chinese sellers on there but i doubt if you would get a better price there. Disadvantage is the delivery time. China is far away. I get my goods mostly in about 2 weeks, sometimes it's just one week. (that's in The Netherlands, don't know where you are located?)

Yeah, i thought i'd just mention it, but i don't know, there are ways to let it start from itself. When the crank is in a certain position it is able to start by itself, but most of the time you have to give it a quick push.

Good luck, and let us know what you're doing.

[Chance Jackson]

Thanks for the link