Watercooling with a central heating radiator?

[CustardInc]

So I'm completely new to water cooling, I own a closed loop cooler and I know the names of the water cooling parts and assembly, but I have no real experience.

I presume it's possible to use a household radiator as a passive radiator in a loop, but I've got a couple of questions. First, do I have to be worried about what the radiator and waterblocks are made of- are the metals important? Second, will I need a significantly more powerful pump than the standard D5?

Thanks!

P.S. the rad I had in mind is this http://www.screwfix.com/p/flomasta-t...-x-800mm/38602 It's rated for 1505 BTU/hour, which equates to 441W, which is in theory plenty my PC (4670K, HD7850 which I'll probably upgrade in the near future)

The reason for using this kind of radiator is because they're far cheaper and passive, although I suppose the increase in pump power may negate quietness of no fans. It's also more fun

[peterb]

At that price it's worth trying, although not the most efficient cooling method because you won't have very big temperature difference cause of the volume of water.

You won't need a bigger pump because the main constraint will be the flow resistance through the water block. You will need to think about pressures though because of the height of the radiator. Connections might be tricky too, the radiator will probably have 15 mm fittings, you could use reducers to get that down to 8mm copper pipe and then use flexible tubing to connect to that - somehow!

Interesting project though.

[CustardInc]

At that price it's worth trying, although not the most efficient cooling method because you won't have very big temperature difference cause of the volume of water.

You won't need a bigger pump because the main constraint will be the flow resistance through the water block. You will need to think about pressures though because of the height of the radiator. Connections might be tricky too, the radiator will probably have 15 mm fittings, you could use reducers to get that down to 8mm copper pipe and then use flexible tubing to connect to that - somehow!

Interesting project though.

You say there won't be much of a temperature difference because of the volume of water, what two temperatures are we comparing to get this difference?

When you say I will need to think about pressures, what do you mean here, since you said the biggest obstacle will be the water block I assumed the D5 was capable in terms of pressure?

I had a quick look at some more powerful pumps, ones designed for aquariums with ~2000L/H compared to the 1200-1500 of the D5, they come in at around £20-30, so I'm guessing they must be louder than a D5 given how much they cost in comparison. Now to source a cheap and ideally decent water block for my processor.

Thanks for the advice!

[herulach]

So I'm completely new to water cooling, I own a closed loop cooler and I know the names of the water cooling parts and assembly, but I have no real experience.

I presume it's possible to use a household radiator as a passive radiator in a loop, but I've got a couple of questions. First, do I have to be worried about what the radiator and waterblocks are made of- are the metals important? Second, will I need a significantly more powerful pump than the standard D5?

Thanks!

P.S. the rad I had in mind is this http://www.screwfix.com/p/flomasta-t...-x-800mm/38602 It's rated for 1505 BTU/hour, which equates to 441W, which is in theory plenty my PC (4670K, HD7850 which I'll probably upgrade in the near future)

The reason for using this kind of radiator is because they're far cheaper and passive, although I suppose the increase in pump power may negate quietness of no fans. It's also more fun

It will probably work, but bear in mind thats only rated at 440W at a 70/20 water/air temp. You'll have huge water volume which may make up for it (basically it gives you a lag) but honestly, by the time you have fittings (15mm to 1/2" internal should be doable, then you can either get 1/2" barbs or reduce it to G 1/4"), the extra hose you need etc I'd be surprised if it gave better performance than a thin 360 with fans.

Its cool though.

[peterb]

You say there won't be much of a temperature difference because of the volume of water, what two temperatures are we comparing to get this difference?

When you say I will need to think about pressures, what do you mean here, since you said the biggest obstacle will be the water block I assumed the D5 was capable in terms of pressure?

I had a quick look at some more powerful pumps, ones designed for aquariums with ~2000L/H compared to the 1200-1500 of the D5, they come in at around £20-30, so I'm guessing they must be louder than a D5 given how much they cost in comparison. Now to source a cheap and ideally decent water block for my processor.

Thanks for the advice!

As herulach said, you will have a large volume of water to heat, so the temperature difference between the radiator and the ambient temperature will be small, and heat transfer depends on temperature difference. As for water pressure, I was referring to the static head of water, the top of the radiator is 800 mm above the bottom, which is about 2 feet. 32 feet of water is roughly 15 psi so two feet will be about 1 psi. (I'll conversion to metric units to you!). Of course, any additional height adds to the static pressure.

Edit: just re-read the specs, the height is 300 mm, or about 1 foot, so the static pressure will be about .5 psi. But there is a large volume if you do get a leak.

[CustardInc]

but honestly, by the time you have fittings (15mm to 1/2" internal should be doable, then you can either get 1/2" barbs or reduce it to G 1/4"), the extra hose you need etc I'd be surprised if it gave better performance than a thin 360 with fans.

I thought that then you reduce the diameter, the pressure and hence flow rate would rise? I haven't really looked into it, but I assumed tubing was relatively cheap. If not, I wouldn't be surprised if I could just buy generic clear hose without the 'for water cooling' mark up and it wouldn't change anything, unless generic hose degrades faster or something. I have a Prodigy M for my case, so I could maybe get a thin 240mm + a 120/140 and maybe another 120 in the bottom. I haven't looked into pricing too much but I'd guess using a combination of radiators to achieve the same surface area as a larger one will be more expensive than just using a larger one, plus the cost of more fittings.

Thanks for giving me more to think about. I'm glad no one's taken a wrecking ball to my plans yet!

[watercooled]

Just found this project after searching: http://digdilem.org/cooling/

[Biscuit]

https://www.youtube.com/playlist?lis...Zxn3Z4t1_xFunu

That playlist might be worth a watch. Its Linus building a whole room of PCs connected in a single loop.
Cant add much to Herulach's comments other than to just say... I wouldn't

[GoNz0]

better getting a small rad, quiet pump and fan imho of 6 years water cooling.
that rads designed to dissipate 80 degree water, it just won't work without a pump going flat out to try and circulate.
then you have the crappy coatings flaking off and blocking the pump and block.

[CustardInc]

As herulach said, you will have a large volume of water to heat, so the temperature difference between the radiator and the ambient temperature will be small, and heat transfer depends on temperature difference. As for water pressure, I was referring to the static head of water, the top of the radiator is 800 mm above the bottom, which is about 2 feet. 32 feet of water is roughly 15 psi so two feet will be about 1 psi. (I'll conversion to metric units to you!). Of course, any additional height adds to the static pressure.

Edit: just re-read the specs, the height is 300 mm, or about 1 foot, so the static pressure will be about .5 psi. But there is a large volume if you do get a leak.

Ah, I understand now. Presumably if there isn't much heat transfer going on, the water will just heat up and then there will be more heat transfer. I think I remember seeing a passively cooled small-form-factor PC that used copper foam as a heatsink, the more it heated up, the more heat it dissipated. I'm guessing it's the same idea here.

Will the higher pressure potentially cause concern with fittings like barbs? I'm thinking that strain on the pump won't be an issue once it gets going, in the same way that a fan draws more power when it starts spinning? I won't pretend to fully understand this

Also, I did a quick calculation using the equation found at the top of the wikipedia page on head pressure (http://en.wikipedia.org/wiki/Pressure_head) and found it to be ~2943Pa, or 0.43PSI. Also I'll try to avoid leaks

[peterb]

Having that large volume of water will act as a heatsink anyway. Water has a relatively high specific heat capacity, i.e. it takes quite a lot of energy to heat a given mass. in other words, if you has a kilogram of water, and a kilogram of aluminium, putting the same amount of energy into each will result in a lower temperature rise in the water than the aluminium.

[abaxas]

TBH dont bother with the rad. You'll need a header tank anyways and that'll be more cooling than you'll ever need!