Passive radiator construction

Axle · 02-16-2003, 06:58 PM

I've only ever constructed one radiator, which was a miserable failure. It kept things near 34C, but it was exposed to our chilly outside winter air (it's currently -12C). It was built under size constraints, but a difference of 46C is still quite a bit. This is it right here, I'm back to the bucket for the time being (I had to remove it today- turned the pump off last night and it was frozen solid). Images are clickable(56k alert):

So that was defiently a failure & has now been retired.

Now I've got ~18ft of 1/2"ID copper tubing, as well as ~10ft of 1/4"OD softset tubing and I'm curious as to which everyone thinks will work better. The smaller diameter would slow down the flow sufficiently and probably cool quite well, but it may prove to be a tax on my Maxi Jet 1200 (295GPH & a TC4/Innovatek GF4 to get through). I've been thinking about the best way to do this, too, wind it tightly, loosely, ??? I've also been thinking about putting it in a larger diameter tube, filled with seperate water that doesn't mix, but don't know how well that might work. Rad/HC watercooling (actually water cooling the rad and HC) has been an interest of mine for a little while now. The 1/4":

If I do go with the 1/2" tubing, I would like to model it off Gerwin's design (if you stop by mate), but am looking for possible improvements. As far as I can tell yours is around the size of a good sized case (~20"x15"?), and while that'd be fine, a little smaller would be nice.

Suggestions? Comments? Ideas? Anthing would be very much apprechiated.

gmat · 02-17-2003, 05:37 AM

What about burying that tube ? Or put it under the living room tiles ? (provided, you've got tiling in your living room

) That would have many advantages:
* very good cooling through extensive lengths of tube running in the ground
* stable temps (potected from outside temps)
* heated tiles (nice & warm)

That implies some heavy duty work indeed...

Was just an idea.
Good luck

Axle · 02-17-2003, 08:49 AM

That would be ideal for me, and whenever I move that's exactly what I'll be doing. But for now I'm in a room on the second floor, and on top of that everything's carpeted :shrug:

I think I'll go ahead with Gerwin's design and see how it goes, copper pipe is real cheap around here ($3 for 18 ft).

Axle · 02-22-2003, 03:03 PM

small update: Well, at least it hasn't caught on fire. Final price for the tubing and Ts came out to around $10, $11 which isn't too shabby. My 1.2T-bird heat factory now idles at a balmy 39-40c, and under an hour or so of load made it all the way up to 44c. But - woohoo! - the temp actually goes back DOWN once it's under idle again (novel concept for a bucket person). All pipes seem to be warm/hot, and about evenly- so I'd say it works mighty good in that respect.

There's a pic attached... me and my (lack of) imigination copied Gerwin exactly, or pretty close to it, which I'm sorry for

I'm looking for improvements, though. 40c isn't bad, but I think maybe it could be better. Room temp's around 22, but system temp (where the is sealed in) is 28. No way to get water temp, but maybe I'll see if this neat probe thing I have can do something. So any ideas? Fins or something?

Axle · 02-22-2003, 03:05 PM

dope.

Puzzdre · 02-22-2003, 04:50 PM

Nice and clean job you did there!
Is there a freezer near? You can put it in it, and have some nice temps...

Gerwin · 02-22-2003, 06:44 PM

Axle: Don't feel bad about copying my design. Actually I feel honoured by it and by the fact that appearantly, my ideas are correct. Your rad looks very good, better then mine actually, because you've soldered it instead of using compression fittings. I wish I had the room and tools to do such fine soldering. Unfortunately, in my old appartment, with wooden floors, the risk of fire is too great to do a soldering job, so I had to go with compression fittings. Anyway, I'm glad that it cools well and evenly. The only way I can think of for improvement is to make it even bigger

, or go for fins, which is even better, because you get a bigger cooling area with the same flow resistance. But it would be a hell of a job to solder that. But if you decide to do that, I'd be very interested in how you do it. Looking forward to pics

PS: About the size of my rad: I've recently enlarged it. It's about twice the size of a big case now. Space is no problem, because I've just put it behind my desk against the wall, so you don't even notice it's there. Yup, size matters

Axle · 02-23-2003, 09:37 AM

I really don't know about the fins... I've soldered pipe that I've cut in half & flattened out (good luck finding copper sheet around here), but this would be mucho money in tubing, and I'm kind of doubtful that it'd do real well. I'll think of something, though, maybe ebay will spark an idea or two.

Wow, now that's big. must be the size of a desk!! Get any temp drop on 2x the size?

Puzzdre: I wish!! I mean we do have a real big one here in PA known as the outdoors, but it doesn't work 5 months out of the year. :shrug:

Gerwin · 02-23-2003, 03:23 PM

Quote:

Originally posted by Axle
Wow, now that's big. must be the size of a desk!! Get any temp drop on 2x the size?

Not really. Was worth a try though, and fun.

nicozeg · 02-23-2003, 06:09 PM

Axle, U could solder long horizontal copper wires over the pipes , just like most refrigerator's condenser. Those are designed for passive convective cooling, using the space between the fridge's back and the wall as a chimney.

Another usefull thing is painting it in silver color to improve radiation (the real one, where copper is poor)

Here's the idea:

Cathar · 02-23-2003, 08:09 PM

While I admire the determination, I'm asking myself why not just buy a heater-core?

A good heater-core like the one I use ('87-'94 Toyota Camry Nippon Denso made core) offer around 1.9m^2 of total cooling surface area.

To match that, even in a passive mode, using say 1/2" ID copper, or 5/8" OD copper tubing, would require around 10m (~32') of tubing.

Sticking a small shroud and a silent (as good as) Papst 50CFM 12CM fan on the heater-core would still result in far better cooling, and then your pump doesn't have to fight to push the flow through 10m of tubing that turns multiple bends.

Just curious.

Gerwin · 02-24-2003, 01:11 AM

Quote:

Originally posted by Cathar
While I admire the determination, I'm asking myself why not just buy a heater-core?

A good heater-core like the one I use ('87-'94 Toyota Camry Nippon Denso made core) offer around 1.9m^2 of total cooling surface area.

To match that, even in a passive mode, using say 1/2" ID copper, or 5/8" OD copper tubing, would require around 10m (~32') of tubing.

Sticking a small shroud and a silent (as good as) Papst 50CFM 12CM fan on the heater-core would still result in far better cooling, and then your pump doesn't have to fight to push the flow through 10m of tubing that turns multiple bends.

Just curious.

Because:
1.Although a heatercore has the same or greater cooling surface area, it's not well suited to passive cooling. When air is forced through it, a heater core is far more efficient then just copper piping, but when used passively, most of the surface area is unused, because it's 'inside' the core and in contact mostly with trapped air, heating mostly the fins that are very close to eachother (sorry for this horrible english sentence, but you get the idea). A heatercore gets really good with a shroud and a fan, like you mentioned, and I insist on passive cooling, for which a more spread design is better suited.
2. The radiator that I and Axle built, is designed in such a way, that most of the piping runs parallel. This means the flow resistance is extremely low, as is proven by the fountain of 1.5 mtr that my Eheim 1046 produces, despite having to run through a cpu cooler, a nb cooler, a gpu cooler and two hdd coolers. The design also gets rid of air very easily.
3. This radiator cannot be bought in any shop, which makes it unique and something to show off.
4. Size matters.

Myten · 02-24-2003, 05:10 PM

put that system of pipes in a watercontainer outside and weve got ourselves some cooling. especially i you live in a country where its collllld

example: take a smaller system of those cupperpipes and put them in a jeep-tank say 30 litres or so, make som nice-looking connections and put it outside your window. voila cheapass-kickass-radiator.

gmat · 02-24-2003, 06:23 PM

Quote:

Originally posted by Cathar
(heater core, adding a fan)

1 - i can hear any fan, even the wonderful Papst 4412 N/2GL, undervolted. I'm not bionic, i'm even a heavy metal addict (read, damaged ears). A fan is never silent, unless it's turned off.
2 - adding a fan in a system where your primary goal is to *suppress* every source of noise and fan... is to throw your goals to the bin
3 - a heater core has densely packed fins, usually 1mm to 2mm across. This is not suitable for passive convection cooling. Try any onlince calculator, for optimal (and working) convection you'll end up with fins spaced about 5mm (at least), provided you're using fins about 20mm long, placed vertically of course.
4 - Size matters

02-16-2003, 06:58 PM	#1
Axle Cooling Savant Join Date: Aug 2002 Location: Wind Gap, PA Posts: 112	Passive radiator construction I've only ever constructed one radiator, which was a miserable failure. It kept things near 34C, but it was exposed to our chilly outside winter air (it's currently -12C). It was built under size constraints, but a difference of 46C is still quite a bit. This is it right here, I'm back to the bucket for the time being (I had to remove it today- turned the pump off last night and it was frozen solid). Images are clickable(56k alert): So that was defiently a failure & has now been retired. Now I've got ~18ft of 1/2"ID copper tubing, as well as ~10ft of 1/4"OD softset tubing and I'm curious as to which everyone thinks will work better. The smaller diameter would slow down the flow sufficiently and probably cool quite well, but it may prove to be a tax on my Maxi Jet 1200 (295GPH & a TC4/Innovatek GF4 to get through). I've been thinking about the best way to do this, too, wind it tightly, loosely, ??? I've also been thinking about putting it in a larger diameter tube, filled with seperate water that doesn't mix, but don't know how well that might work. Rad/HC watercooling (actually water cooling the rad and HC) has been an interest of mine for a little while now. The 1/4": If I do go with the 1/2" tubing, I would like to model it off Gerwin's design (if you stop by mate), but am looking for possible improvements. As far as I can tell yours is around the size of a good sized case (~20"x15"?), and while that'd be fine, a little smaller would be nice. Suggestions? Comments? Ideas? Anthing would be very much apprechiated. __________________ "Once we've got those bugs flattened out, we'll be running on flat bugs"

02-17-2003, 08:49 AM	#3
Axle Cooling Savant Join Date: Aug 2002 Location: Wind Gap, PA Posts: 112	That would be ideal for me, and whenever I move that's exactly what I'll be doing. But for now I'm in a room on the second floor, and on top of that everything's carpeted :shrug: I think I'll go ahead with Gerwin's design and see how it goes, copper pipe is real cheap around here ($3 for 18 ft). __________________ "Once we've got those bugs flattened out, we'll be running on flat bugs"

02-22-2003, 03:03 PM	#4
Axle Cooling Savant Join Date: Aug 2002 Location: Wind Gap, PA Posts: 112	small update: Well, at least it hasn't caught on fire. Final price for the tubing and Ts came out to around $10, $11 which isn't too shabby. My 1.2T-bird heat factory now idles at a balmy 39-40c, and under an hour or so of load made it all the way up to 44c. But - woohoo! - the temp actually goes back DOWN once it's under idle again (novel concept for a bucket person). All pipes seem to be warm/hot, and about evenly- so I'd say it works mighty good in that respect. There's a pic attached... me and my (lack of) imigination copied Gerwin exactly, or pretty close to it, which I'm sorry for I'm looking for improvements, though. 40c isn't bad, but I think maybe it could be better. Room temp's around 22, but system temp (where the is sealed in) is 28. No way to get water temp, but maybe I'll see if this neat probe thing I have can do something. So any ideas? Fins or something? __________________ "Once we've got those bugs flattened out, we'll be running on flat bugs"

02-22-2003, 03:05 PM	#5
Axle Cooling Savant Join Date: Aug 2002 Location: Wind Gap, PA Posts: 112	dope. __________________ "Once we've got those bugs flattened out, we'll be running on flat bugs"

02-22-2003, 04:50 PM	#6
Puzzdre Cooling Savant Join Date: Aug 2002 Location: Croatia Posts: 969	Nice and clean job you did there! Is there a freezer near? You can put it in it, and have some nice temps... __________________ 'Out of cheese error... ...please reboot the universe (press the GBL to continue)'

02-17-2003, 05:37 AM	#2
gmat Thermophile Join Date: Mar 2001 Location: France Posts: 1,221	What about burying that tube ? Or put it under the living room tiles ? (provided, you've got tiling in your living room ) That would have many advantages: * very good cooling through extensive lengths of tube running in the ground * stable temps (potected from outside temps) * heated tiles (nice & warm) That implies some heavy duty work indeed... Was just an idea. Good luck

02-22-2003, 06:44 PM	#7
Gerwin Cooling Neophyte Join Date: Sep 2002 Location: Amsterdam Posts: 37	Axle: Don't feel bad about copying my design. Actually I feel honoured by it and by the fact that appearantly, my ideas are correct. Your rad looks very good, better then mine actually, because you've soldered it instead of using compression fittings. I wish I had the room and tools to do such fine soldering. Unfortunately, in my old appartment, with wooden floors, the risk of fire is too great to do a soldering job, so I had to go with compression fittings. Anyway, I'm glad that it cools well and evenly. The only way I can think of for improvement is to make it even bigger , or go for fins, which is even better, because you get a bigger cooling area with the same flow resistance. But it would be a hell of a job to solder that. But if you decide to do that, I'd be very interested in how you do it. Looking forward to pics PS: About the size of my rad: I've recently enlarged it. It's about twice the size of a big case now. Space is no problem, because I've just put it behind my desk against the wall, so you don't even notice it's there. Yup, size matters __________________ my watercooled system: http://www.xs4all.nl/~philippo

02-23-2003, 09:37 AM	#8
Axle Cooling Savant Join Date: Aug 2002 Location: Wind Gap, PA Posts: 112	I really don't know about the fins... I've soldered pipe that I've cut in half & flattened out (good luck finding copper sheet around here), but this would be mucho money in tubing, and I'm kind of doubtful that it'd do real well. I'll think of something, though, maybe ebay will spark an idea or two. Wow, now that's big. must be the size of a desk!! Get any temp drop on 2x the size? Puzzdre: I wish!! I mean we do have a real big one here in PA known as the outdoors, but it doesn't work 5 months out of the year. :shrug: __________________ "Once we've got those bugs flattened out, we'll be running on flat bugs"

02-23-2003, 08:09 PM	#11
Cathar Thermophile Join Date: Sep 2002 Location: Melbourne, Australia Posts: 2,538	While I admire the determination, I'm asking myself why not just buy a heater-core? A good heater-core like the one I use ('87-'94 Toyota Camry Nippon Denso made core) offer around 1.9m^2 of total cooling surface area. To match that, even in a passive mode, using say 1/2" ID copper, or 5/8" OD copper tubing, would require around 10m (~32') of tubing. Sticking a small shroud and a silent (as good as) Papst 50CFM 12CM fan on the heater-core would still result in far better cooling, and then your pump doesn't have to fight to push the flow through 10m of tubing that turns multiple bends. Just curious.

02-24-2003, 05:10 PM	#13
Myten Cooling Neophyte Join Date: Sep 2002 Location: sweden Posts: 19	put that system of pipes in a watercontainer outside and weve got ourselves some cooling. especially i you live in a country where its collllld example: take a smaller system of those cupperpipes and put them in a jeep-tank say 30 litres or so, make som nice-looking connections and put it outside your window. voila cheapass-kickass-radiator. __________________ "to fully understand something and to misunderstand the same thing, dont always exclude one another - kafka"

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