DACS,
I suggest using all copper on the water block BUT, skive it on the part where it contacts water... remember copper absorbs heat better but has problems dissipating it, so you need to get the copper as thin as possible to dissipate as much heat to the water as possible.... not sure how you will do it but I envision small very thin copper fins in the water block section where water passes through it....
and not much copper between it and the proc heatshield to promote heat transfer to the water better.
Forum Topic
MY CPU Water Cooling Project
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remember the skived all copper heatsinks from thermalright of old? The almost 1kg ones with a copper base?
I was thinking of something with a similar arrangement, just on a smaller level.
copper rods standing from the water block base will not be effective (gigabyte 3D galaxy II water block) and I think putting very small fins may be insufficient to dissipate excess heat, even if you point the inlet on it..... taller 2 to 3 mm skived copper fins running the entire length of the input to the output hose may work better as an alternative. -
There are more ways to address this. Either to:
1. Promote more surface area (by having fins), or
2. Increase water flow rate across the waterblock.
Anyway, to reply on some of your statement:
remember copper absorbs heat better but has problems dissipating it,
The perceived "dissipation" problem of copper stems out of the fact that copper is heavier (per unit volume) than aluminum. While aluminum has a lower thermal conductivity, it also has a lower density. You can have potentially more surface area of aluminum compared with copper for the same weight.
not sure how you will do it but I envision small very thin copper fins in the water block section where water passes through it....
Mechanical integrity aside, having a thinner fin will result in increase in pressure drop across your water block. So one can make a compromise between a thicker fin design, but results in less pressure drop (and more water flow) and a thinner fin, but would require a more powerful pump to force it across the fin.
Anyway I can manage to come up with a waterblock design, but the trickier part is to design the heat dump (aka radiator, or cooling tower in my new idea).
I suppose I need to produce some sketch for visuals. -
for radiators, pure aluminum then thin fin design plus thin tubes with as much surface area as possible.
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Mechanical integrity aside, having a thinner fin will result in increase in pressure drop across your water block.
Don't you want to have pressure drop after the water block going to the radiator? lower pressure means water is slower going through the radiator and dumping more heat than it can if it had more pressure.....
unlike automotive radiators, water coolers do not have pressure in their radiators and hence, the slower the water snakes through the radiator, the more heat gets dumped there. -
I'm not talking about (absolute) pressure itself, but rather the amount of work you need to circulate the water inside the circuit, which is basically overcoming pressure drop.
Pressure drop is inevitable but in the context of heat exchange, higher pressure drop equates to high flows, which leads to high velocities (and therefore, turbulence). Turbulent flow makes better heat exchange.
Problem with pressure loss is you need to design your circuit accordingly, meaning you need to have a stronger pump to overcome the pressure drop. -
Hi Guys,
As work is kinda slow (well.. I'm just lazy to work haha), I did some rough calculation of this "evaporative cooling" concept.
Assumptions:
1. 250 W load (typical for OC'ed CPUs)
2. 120L/hr cooling water flow (typical for closed loop AIO liquid coolers such as Nepton 240M)
3. Air RH of 75% (typical humidity in Pinas, if not a bit higher)
4. Temperature (dry bulb) of 35degC. This is a bit extreme, normally seen during summer
Key parameters to look at:
1. CWR (inlet to CPU water block) temperature is more than 3degC lower (31.8degC) than inlet air temperature. This is the power of evaporative cooling. You will never see this in any (sensible) cooling water loops. Imagine if the air temperature is at 27-28degC. Your coolant will be around 23-24degC!
2. With a well-designed water block, the CPU temp can be as low as 52degC under load (20degC temperature delta, air temp = 35degC).
3. The air is driven by a typical 55-60 CFM fan. Unlike traditional water cooling setup, there's a diminishing return when increasing the air flow. More on that later when I fine tune the design.
Things to consider:
1. Evaporative cooling is an open loop system. You need to have the coolant get in touch with air. This introduces some issues not seen in closed loop system, such as dirt entrainment and bacterial growth. These are not insurmountable however and these can be addressed
2. As this is an open loop system, proper installation has to be done and it's not going to be as robust as installing radiators. I believe that space required for this will be smaller however, with a properly set up system in place.
3. Main disadvantage of this is you need makeup water to replenish the lost water due to evaporation. In this particular calculation, you need to fill the reservoir 1 liter of water every 2 hours.
That's all for now, I may have to fine tune this and propose some initial sketch :) -
^ Will the evaporator be located outside your room/house?
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awakeruze: Not at all. It's a standalone piece of equipment. Rough (very) dimensions like 150mm ID x 300 mm height cylinder.
Actually, it can be modded and be attached on a case panel.
I'll come up with a sketch para makita nyo. -
^ IMO it's not a good idea due to several reasons:
1. Room humidity increases. Since we live in a tropical country we know how uncomfortable a hot and humid room is.
2. Evaporative cooling performance decreases with humidity. -
1. Room humidity increases. Since we live in a tropical country we know how uncomfortable a hot and humid room is.
Pretty much true, but the system can be designed not to produce 100% RH hot air. In Pinas, most probably you have an aircon if you have a closed room, or room with opened windows if you rely on electric fan. Aircon is a dehumidifier by design and opened windows takes care of humidity accumulation.
With the expected loads, I think the increase in humidity will be tolerable.
Evaporative cooling performance decreases with humidity.
Pretty much true as well, although even with 100% RH, the system can still cool down due to sensible heat loss, like what closed loop coolers are doing. The one I showed has a 75% RH at (dry bulb) temperature of 35degC, which is very, very extreme, even in Pinas conditions.
In general, if correctly designed, it can perform better than closed loop (even the custom water cooling) solutions. After all, why have we observed evaporative coolers (for rooms) in the market as of late? -
I think I have to put this in the backburner and focus my effort in making an mITX case that has all the bells and whistles
<click here for link>
What you guys think? -
mga master may tanong po sana ako.
san po kaya pwede mag aral or training gumawa ng mga water cooling system ng cpu dito sa manila? plan ko kasi mag aral para in the future pwede ko gawin business sa probinsya.
salamat