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Discussion Starter #1
So I've got a pump, block (incoming Supreme LT) and may use a free res i received with the pump. I also got a 120mm Tt rad but it's aluminium, so i don't want to use that with my shiny LT


Therefore i need some other method of cooling. The original plan was to use a horizontal volenti cooler or at worst my already built vertical bong, however the incredible heat capacity of a mass of water has been brought to my attention courtesy of MCPetrolhead and Year 11 Chemistry.


So time for some maths. Some of you may know this formula:
q = m C (delta)T
Where q = quantity of heat (joules), m = mass (of water, grams), C = specific heat capacity (J/k/g), deltaT = Change in temperature (celcius)

Q = 150W (approximate CPU output) x 60 seconds x 60 minutes x 10 hours = 5,400,000
C = 4.2 J/k/g (just a fact for water. You can research how this is calculated if you like)
m = 10 Litre res, may change to 5L or 20L or something.
t = ?

Therefore, transposing,
T = q / C m
= 5,400,000J / 4.2 J/k/g * 10000g
= 128.5°

TL;DR (or to save brain asplosions): 128°


Over 1 hour

T = q / C*m
= (150J*60s*60m) / 4.2*10000g
= 540,000J / 42000
= 12.8° over 1 hour of 150W load.

This is far more manageable. I think close to 12 degrees can be dissipated naturally

Obviously 128 degrees isn't too good. However there are many variables to consider:
1: the water/res will dissipate heat. If i have an opening (maybe a grill too?) in the top of the res some evaporation cooling will also take place
2: the load will not be a constant 150W. Much of the time will be at idle.
3: i can cycle reusable gel "hotpaks" - you know those things you can stick in the freezer or microwave?

Predictions:
The water and CPU temperature will rise exponentially as greater heat is added.

Comments, opinions, contradictions of my bucket chemistry?
 

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... that hurt my brain

i will send you my medical bill
 

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i think this would work really well.. but you also forgot the factor of the dreaded air temperature. your water will sit at room temp and that is only going to go up from there as your CPU dumps heat. i think it will work fairly well as watercooling with a radiator really cant get below air temperature anyway (unless you have some extreme radiators and then it will only be 1-4*C). i think it will work fine, but for how long is the issue, it will just heat up and up until it gets to the point were the waters ability to remove the heat matches the increase of heat entering your bucket. this might work for a few hours or might only last 30 minutes. try it and find out? i want to know.
 

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Discussion Starter #5
Quote:

Originally Posted by Kal777 View Post
i think this would work really well.. but you also forgot the factor of the dreaded air temperature. your water will sit at room temp and that is only going to go up from there as your CPU dumps heat. i think it will work fairly well as watercooling with a radiator really cant get below air temperature anyway (unless you have some extreme radiators and then it will only be 1-4*C). i think it will work fine, but for how long is the issue, it will just heat up and up until it gets to the point were the waters ability to remove the heat matches the increase of heat entering your bucket. this might work for a few hours or might only last 30 minutes. try it and find out? i want to know.
yes this would be impossible with 24/7 use. Thankfully i only have it on for 10 hours max (more like 5-6 hours 5 days of the week). As i said i can always add more water or chill it a bit
 

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Try the towel trick in the bong to cool the water.
could also try an external copper pipe loop? or a copper loop inside the bong?
also.
 

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Quote:

Originally Posted by T3h_Ch33z_Muncha View Post
edited the OP for effect

....... so the water would be 128°?
 

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Discussion Starter #13
in a completely closed environment where none of that heat is radiated into the environment (which it most certainly will be), the quantity of heat is constant etc the math would be completely correct
 

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Your formula won't work will it?

The water won't ever get to 128c as its going to boil and start evaporating @100c.

Either way... If the water is even anywhere near 100c it will be rubbish and moving heat away from the CPU.

Therefore you are going to need some sort of cooler in the loop, whether it be an external loop in a cold place, radiator or bong.
 

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Discussion Starter #16
Quote:


Originally Posted by The_Rocker
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Your formula won't work will it?

The water won't ever get to 128c as its going to boil and start evaporating @100c.

Either way... If the water is even anywhere near 100c it will be rubbish and moving heat away from the CPU.

Therefore you are going to need some sort of cooler in the loop, whether it be an external loop in a cold place, radiator or bong.

I don't think so. If necessary i can always chuck a couple of towel racks in to cool the water.
 

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^Yup^

Have to perform some additional work, move the heat from the water.

If you cant/dont want to use the rad in the main loop, get a second (smaller?) pump and run water directly from the res through the rad.

Of course, this is still ultimately going to dump heat into the atmosphere, albeit at a much higher rate than simple convection directly from the res. Solution here would be to purchase a length of clothes-dryer ducting and exhaust the warm air to the outdoors.
 

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If you want a cheap, yet effective radiator, get an old window air conditioner. The only requirement is that you don't pay more than $30 for it, and that it was rated for at least 6,000 BTUs. Take the thing apart, and make sure to release the freon inside the compressor outside as it smells really bad (Although it isn't toxic). Then hook up the radiator on the low pressure side to your loop. I'm in the process of doing this with a 5050 BTU AC unit, and so far it's going great.

Another option, if you don't want a radiator, is to use your tap water. Basically, use an electronic valve + temperature sensor to control the flow of tap water into the reservoir. Basically have the tap add more water into the reservoir whenever the temperature of the water reaches 30C. Obviously you will need some way of draining the excess water out of the reservoir as well.
 

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Quote:


Originally Posted by Mitche01
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Just to point out, the Specific heat capacity you have quoted is Joules/KELVIN/gram. So the units dont match in your maths therefore 128 degrees celcius is wrong.

you cant mix and match units/prefixs in equestions. Its called a homogenous equation.

This does not matter.
He is talking about the change in temperature, so an increase of 1 degree (kelvin) is the exact same as 1 degree (celcius) increase.

The calculations he is doing is not to represent real life, I have personally done what he is talking about with a 20L water tank. I found that after a few hours of full load with my i5 at 4.4GHz i saw an approximate increase of 10 degrees celcius.

I think the only way to test it Ch33z is to experiment. If you hook it all up then see what equilibrium temperature you get at idle and the equilibrium temperature at load is it would allow you to tell if it would be viable. Only problem with this though is that it will take several hours to reach the load equilibrium temperature and it will vary throughout the day as the ambient temperature changes.
 
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