[Smykster]

Sorry if I sound like an idiot, but I see lots of people adding larger heatsinks and going WC for the reasons beyond lowering the temps of their hardware. Some seem to be under the impression that adding more effective heat dissipation units(heatsinks, WC) will lower the AMBIENT temp in a room that would otherwise be stiflingly hot and inhabitable in the warmer months of the year. I have a few questions about this and possible solutions.

My room can get pretty toasty in the summer with my rig and I would love to have it be a bit more habitable. It's is also my understanding the due to the laws of conservation of matter, mass and energy, no amount of dissipative cooling will actually lower the temperature of an enclosed room. Infact, over time and without any environmental dissipation(I know this is not possible, but in theory) within the environment, temps will rise indefinitely no matter what cooling solution one uses. The only way I could think this would not occur is through some sort of endothermic reaction, perhaps phase change. Even then I don't know what the heat output is on one of these devices.

Having this knowledge, it would be beneficial to open a window and have a windows fan blow air outside to increase the effectiveness of the dissipation process not just in the rig, but in the ambient setting. Or perhaps go a step further and create and tube that attaches to the exhausting case fans and run the tube out the window. This would also work vice versa in winter, if the humidity was low enough outside one could connect this window tube to the intake case fans.

Just trying to come up with some relatively inexpensive and "green" methods of taking cooling, for both hardware and living environment a step further, and ideas?

 

[Shadowclock]

Quote:

Originally Posted by Smykster Sorry if I sound like an idiot, but I see lots of people adding larger heatsinks and going WC for the reasons beyond lowering the temps of their hardware. Some seem to be under the impression that adding more effective heat dissipation units(heatsinks, WC) will lower the AMBIENT temp in a room that would otherwise be stiflingly hot and inhabitable in the warmer months of the year. I have a few questions about this and possible solutions. My room can get pretty toasty in the summer with my rig and I would love to have it be a bit more habitable. It's is also my understanding the due to the laws of conservation of matter, mass and energy, no amount of dissipative cooling will actually lower the temperature of an enclosed room. Infact, over time and without any environmental dissipation(I know this is not possible, but in theory) within the environment, temps will rise indefinitely no matter what cooling solution one uses. The only way I could think this would not occur is through some sort of endothermic reaction, perhaps phase change. Even then I don't know what the heat output is on one of these devices. Having this knowledge, it would be beneficial to open a window and have a windows fan blow air outside to increase the effectiveness of the dissipation process not just in the rig, but in the ambient setting. Or perhaps go a step further and create and tube that attaches to the exhausting case fans and run the tube out the window. This would also work vice versa in winter, if the humidity was low enough outside one could connect this window tube to the intake case fans. Just trying to come up with some relatively inexpensive and "green" methods of taking cooling, for both hardware and living environment a step further, and ideas?

1) You cannot lower your ambient temperature by adding any extra cooling to your rig...if anything you are adding heat to your ambient by adding components to your rig.
2) Opening my window in the summer where it is 120F is a bad idea.
3) Assuming correct connection with a tube to go out the window; 1 tube for 1 exhaust fan is not enough for most systems here on OCN, although you would be correct this would lower your ambient room temps by exhausting the heat from your system outside (again assuming the "tube" is properly built)
4) Under the right circumstances (humidity, etc...) yes you can intake cold air during the winter...many people already do this, I am sure you can search for a current mod for it.

 

[MrDeodorant]

Quote:

Originally Posted by Smykster Sorry if I sound like an idiot, but I see lots of people adding larger heatsinks and going WC for the reasons beyond lowering the temps of their hardware. Some seem to be under the impression that adding more effective heat dissipation units(heatsinks, WC) will lower the AMBIENT temp in a room that would otherwise be stiflingly hot and inhabitable in the warmer months of the year.

They are wrong. It's the same amount of heat entering the air. The only thing a better heatsink does is let your CPU dissipate its heat more efficiently (i.e. without getting hot).

Quote:

Originally Posted by Smykster It's is also my understanding the due to the laws of conservation of matter, mass and energy, no amount of dissipative cooling will actually lower the temperature of an enclosed room. Infact, over time and without any environmental dissipation(I know this is not possible, but in theory) within the environment, temps will rise indefinitely no matter what cooling solution one uses. The only way I could think this would not occur is through some sort of endothermic reaction, perhaps phase change.

You are correct; the only way to prevent it is with an endothermic reaction or a one-way phase change, like melting ice. Once you're out of reactants or ice, though, you're done.

Quote:

Originally Posted by Smykster Having this knowledge, it would be beneficial to open a window and have a windows fan blow air outside to increase the effectiveness of the dissipation process not just in the rig, but in the ambient setting. Or perhaps go a step further and create and tube that attaches to the exhausting case fans and run the tube out the window. This would also work vice versa in winter, if the humidity was low enough outside one could connect this window tube to the intake case fans.

It's only beneficial to blow air out of your room if the air that's coming in from the rest of your house is cooler, and you can sustain that. An air conditioner, for example, will have to work harder if you keep blowing it's output out the window.

Another way is with a bong or Naja evaporative cooler, which is the cheapest phase change unit you can get. It raises the humidity a small amount, and it's a lot of work, but it's cheap (if you're already water cooling) and a phenomenal way to keep your computer cool.

Quote:

Originally Posted by Smykster Just trying to come up with some relatively inexpensive and "green" methods of taking cooling, for both hardware and living environment a step further, and ideas?

You seem to have a good grasp of how cooling works. I'm interested to see what you'll end up with.

 

[lithgroth007]

You sound like a student engineer (or an engineer without a ton of heat transfer knowledge.) From what I have seen most people get the best heatsinks they can get their hands on for the best temps. Granted, some of them dont understand that sub ambient temps are not possible, which is what goes along with what you are saying.

Having said that, there are two ways to get lower temps on your chips with air/water cooling.

1.) lower ambient temps. As you said, this is only possible to do by opening a window or some other way of getting your room cooler.

2.) Increasing the heat transfer rate from your cpu/chip to the environment. This is the basic idea behind heat pipes, getting the thermal energy away from the chip as fast as possible. In a perfect world with infinite conduction and convection your chip's temp would be the same temp as the ambient air, but not colder.

You are correct in saying that over time the ambient temp would increase indefinatly from the addition of energy from the chip. But in all reality as long as you have some amount of ventilation in your room the environment will act as a nearly infinite reservoir and the ambient temp wont be effected very much.

The only other way to get lower temps is to use sub-ambient temps, but you need to use protection against condensation with those, which doesnt bode well for most 24/7 rigs.

All in all if you want your room to be cooler in the summer, open a window and use a fan....or turn up the A/C. There really isnt a big need to run tubing around your room.

EDIT:
Little summary

You can's lower your ambient temp without using a lot of energy in endothermic reactions

You can lower your chip temps to near ambient by increasing the heat transfer from the chip to the environment

Your chip will eventually heat up your room, but a little ventilation (open a window) will cool it off, assuming of course that your room is hotter than outside.

If your room is cooler than outside then exhausting air directly from your case to outside should help a little.

The only other way to lower your temps is to use sub ambient cooling (bong, phase, dice, etc.)

 

[Smykster]

Quote:

Originally Posted by Shadowclock 1) You cannot lower your ambient temperature by adding any extra cooling to your rig...if anything you are adding heat to your ambient by adding components to your rig. 2) Opening my window in the summer where it is 120F is a bad idea. 3) Assuming correct connection with a tube to go out the window; 1 tube for 1 exhaust fan is not enough for most systems here on OCN, although you would be correct this would lower your ambient room temps by exhausting the heat from your system outside (again assuming the "tube" is properly built)

1. I am aware of, and this is what I'm, or other should try to avoid if high ambients are the problem.
2. Even if it was 120f outside and you opened a window and had a window fan installed blowing air outside creating a negative pressure in the room, it should lower, or maintain an ambient temperature. This is especially so if your house is using an AC unit, although the rest of the house will not be cooled as effectively if you have a lot of air escaping out the window.
3. It would be possible to have all exhausting fan connected to tubes the exhausted the heated air outside. I can see how this might not be effective or plausible for people who have more than 2-3 exhausting fans or large case fans, but it might work for some who have 1 or 2.

 

[Shadow_UGZ]

Actually since water takes 4 times more energy to raise by 1C it will reduce the heat produced by your PC in turn keeping your room slightly cooler (thus lowering your ambient temps).

 

[Smykster]

Quote:

Originally Posted by lithgroth007 You sound like a student engineer (or an engineer without a ton of heat transfer knowledge.) From what I have seen most people get the best heatsinks they can get their hands on for the best temps. Granted, some of them dont understand that sub ambient temps are not possible, which is what goes along with what you are saying. Having said that, there are two ways to get lower temps on your chips with air/water cooling. 1.) lower ambient temps. As you said, this is only possible to do by opening a window or some other way of getting your room cooler. 2.) Increasing the heat transfer rate from your cpu/chip to the environment. This is the basic idea behind heat pipes, getting the thermal energy away from the chip as fast as possible. In a perfect world with infinite conduction and convection your chip's temp would be the same temp as the ambient air, but not colder. You are correct in saying that over time the ambient temp would increase indefinatly from the addition of energy from the chip. But in all reality as long as you have some amount of ventilation in your room the environment will act as a nearly infinite reservoir and the ambient temp wont be effected very much. The only other way to get lower temps is to use sub-ambient temps, but you need to use protection against condensation with those, which doesnt bode well for most 24/7 rigs. All in all if you want your room to be cooler in the summer, open a window and use a fan....or turn up the A/C. There really isnt a big need to run tubing around your room.

I can understand the hesitation that most would have running tubing all over their room and the logistics of running them outside, but it might show to be quite effective. Maybe I'll give it a go, my rig is close to the window and the window is on the side of the house. As long as I cause no permanent property damage, I don't see why I shouldn't try

 

[DuckieHo]

Quote:

Originally Posted by Shadow_UGZ Actually since water takes 4 times more energy to raise by 1C it will reduce the heat produced by your PC in turn keeping your room slightly cooler (thus lowering your ambient temps).

No, it won't. How would thermal capacity of water reduce the generation of heat?

Once the system hit equilibrium, ambient temps would be exactly the same (if not more since pumps use more power than fans).

 

[lithgroth007]

Quote:

Originally Posted by Shadow_UGZ Actually since water takes 4 times more energy to raise by 1C it will reduce the heat produced by your PC in turn keeping your room slightly cooler (thus lowering your ambient temps).

FALSE, that is absolutely wrong.

The amount of energy (heat) produced by the cpu is CONSTANT regardless of what cooling method used. Water has a higher capacitance for energy as well as a higher convective heat transfer coefficient than air does, which is why it is able to transfer heat better and keep your temps down.

Energy stored per time = Energy in per time - Energy out per time + Energy generated per time.

where energy out is by heat transfer and energy generated is your cpu's thermal Wattage. There is no energy in, and energy stored is a function of the heatsinks temp.

 

[MrDeodorant]

Quote:

Originally Posted by Shadow_UGZ Actually since water takes 4 times more energy to raise by 1C it will reduce the heat produced by your PC in turn keeping your room slightly cooler (thus lowering your ambient temps).

It absolutely will not, except when it lets you run a specific clock rate at a lower voltage than you would be able to on air.

Edit: wow, the nail that sticks up sure does get hammered down.

 

[Shadow_UGZ]

Quote:

Originally Posted by DuckieHo No, it won't. How would thermal capacity of water reduce the generation of heat? Once the system hit equilibrium, ambient temps would be exactly the same (if not more since pumps use more power than fans).

Not necessarily reduce heat but the heat energy would be stored in the water rather than the air. The difference it would make would be very negligible since most of the energy in the water would dissipate in the air anyways once the water warms up enough.

 

[lithgroth007]

Quote:

Originally Posted by MrDeodorant Edit: wow, the nail that sticks up sure does get hammered down.

Especially when its in a forum full of engineers.

 

[Smykster]

Quote:

Originally Posted by Shadow_UGZ Actually since water takes 4 times more energy to raise by 1C it will reduce the heat produced by your PC in turn keeping your room slightly cooler (thus lowering your ambient temps).

Yes, water would require more energy to heat than air, but water is more dense. This means that more particles are being heated evenly and the transfer of heat to water is more effective. In turn though, the heat that your processor is creating is not dissapearing because it takes longer for water to heat up, it is simply being dissipated into the environment more efficiently.

 

[lithgroth007]

Quote:

Originally Posted by Shadow_UGZ Not necessarily reduce heat but the heat energy would be stored in the water rather than the air. The difference it would make would be very negligible since most of the energy in the water would dissipate in the air anyways.

K (conduction), h (convection), and c (specific heat) are all higher (a lot) in water than air, which is why water is better at dissipating heat than air.

Those arent the only contributors though, you have to take into account free stream velocity, boundary layer formation, type of flow, etc....

All in all water is just better.

 

[DuckieHo]

Quote:

Originally Posted by Shadow_UGZ Not necessarily reduce heat but the heat energy would be stored in the water rather than the air. The difference it would make would be very negligible since most of the energy in the water would dissipate in the air anyways once the water warms up enough.

While water can store more energy, the equilibrium room temperature will still end up being the same in the end.

 

[AyeYo]

Quote:

Originally Posted by Shadow_UGZ Not necessarily reduce heat but the heat energy would be stored in the water rather than the air. The difference it would make would be very negligible since most of the energy in the water would dissipate in the air anyways once the water warms up enough.

The heat only gets stored in the water to a point, the radiator is still exhausting heat into the room. If the water stored all the heat, it would keep getting hotter and hotter.

 

[lithgroth007]

Quote:

Originally Posted by DuckieHo While water can store more energy, the equilibrium room temperature will still end up being the same in the end.

This exactly. Even on water you still cant get temps less than ambient. You can just get closer to ambient on full load.

EDIT: messed up my facts with a brain fart.

 

[Smykster]

I'm just trying to come up with some cost effective, low energy, and preferably non invasive cooling solutions or cooling catalysts to aid an acting solution. Has anyone seen or tried anything mentioned?

 

[MrDeodorant]

Quote:

Originally Posted by Shadow_UGZ Not necessarily reduce heat but the heat energy would be stored in the water rather than the air. The difference it would make would be very negligible since most of the energy in the water would dissipate in the air anyways once the water warms up enough.

If the heat is 'stored in the water', the water gets hot. If the water gets hot, the radiators cool it. Then the heat isn't in the water, it's in the air.

Quote:

Originally Posted by Smykster I'm just trying to come up with some cost effective, low energy, and preferably non invasive cooling solutions or cooling catalysts to aid an acting solution. Has anyone seen or tried anything mentioned?

Bongs. Seriously. They chill your water below ambient temperature, but because they rely on evaporation, they don't get it below the dew point, so there is absolutely no chance of condensation. You build them out of PVC pipe, a showerhead, and a spare fan.

 

[AyeYo]

Quote:

Originally Posted by Smykster I'm just trying to come up with some cost effective, low energy, and preferably non invasive cooling solutions or cooling catalysts to aid an acting solution. Has anyone seen or tried anything mentioned?

I'm planning to add a duct from my window to my side intake fan. However, it's quickly getting to that time of year when it's hotter outside than inside, so I'll still need a solution for the summer.