A unique cooling application for you guys...

[Howard]

I think somebody here should be able to help me out.

http://products.semelab-tt.com/pdf/magnatec/ALF16N16W ALF16N20W.pdf

Take a look at page 4 (last page). This transistor will be dissipating up to 200W, and I need to put 16 of these chips in one box (size is not a big deal). Ordinarily, large aluminum extrusions are used for heat sinking, but I think water cooling will remove the heat better and be just as cost-effective as well.

Only problem is, I'm not sure what water blocks to use. I might have to make my own. Thoughts?

 

[aigomorla]

howard is that a fancontroller your building?

Those look like mosfets with 16amp holding capacity? :O

 

[Howard]

I'm not building a fan controller.

These chips are for an audio amp application.

 

[aigomorla]

I'm not building a fan controller.

These chips are for an audio amp application.

and u want to watercool them?

Have u looked at mosfet blocks?
Or even a Dominator Ram block would do it if u had a way to clamp the edges over them.

Mosfet block:
http://www.performance-pcs.com/catal...ducts_id=24498

dominator Ram block:
http://www.performance-pcs.com/catal...ducts_id=31078

u just want the hotside touching the plate, and the water to cool over it correct?

 

[Howard]

No need to constrain yourself too early. All I'm asking to consider is to use water to cool these things. Heat pipes or whatever can be used too.

Those MOSFET blocks are way too small, and the RAM block can't be tapped to accept a screw.

 

[aigomorla]

No need to constrain yourself too early. All I'm asking to consider is to use water to cool these things. Heat pipes or whatever can be used too.

Those MOSFET blocks are way too small, and the RAM block can't be tapped to accept a screw.

lol... is it worthwhile to WC? no..

personally i would attach them on a copper sink.

However the alu if its annodized might be because it doesnt conduct electricity.

 

[Howard]

lol... is it worthwhile to WC? no..

personally i would attach them on a copper sink.

However the alu if its annodized might be because it doesnt conduct electricity.

Air cooling 3200W is better than water cooling 3200W?

 

[aigomorla]

Air cooling 3200W is better than water cooling 3200W?

16 x 200W will require a substaintial radiator with flow.

I dont think you want to go into that messy of a mechanics.

Because your going to be messing with holding capacity of water at flow.

roughly takes 300W of heat @ water moving 1gpm for it to go up 1C.

That means a typical LC'd system can hold 1-1.5gpm ~ 300-400W of heat per 1C.

3200 / 400W ~ 8C variance from the first hot spot to the last hot spot.

Its difficult unless you setup some creative paralell, so you get the 8C spread across everything.... basically paralell 2 units of 8 mosfets.

Then thats not all, you then need a radiator which can handle 3200W and give u a good delta. At least 8C difference... which means.. a VERY MASSIVE radiator... i honestly dont think if its possible to cool this quietly as your nearing the specs of a full blown car rad if you want some silence.

 

[RampantAndroid]

I think somebody here should be able to help me out.

http://products.semelab-tt.com/pdf/magnatec/ALF16N16W ALF16N20W.pdf

Take a look at page 4 (last page). This transistor will be dissipating up to 200W, and I need to put 16 of these chips in one box (size is not a big deal). Ordinarily, large aluminum extrusions are used for heat sinking, but I think water cooling will remove the heat better and be just as cost-effective as well.

Only problem is, I'm not sure what water blocks to use. I might have to make my own. Thoughts?

If space is of no concern, just grab the typical aluminum heatsinks. Just look at heatsink USA or something.

On a different note, what audio amp are you building that will be pushing 200W? When you say dissipating, do you mean that's how much heat? Or how much power you expect to see from the amp outputs?

 

[Howard]

If space is of no concern, just grab the typical aluminum heatsinks. Just look at heatsink USA or something.

On a different note, what audio amp are you building that will be pushing 200W? When you say dissipating, do you mean that's how much heat? Or how much power you expect to see from the amp outputs?

My project is no longer active, but I was going to build an 8-channel amp using this:

http://www.diyaudio.com/forums/soli...amplifier-based-lme49830-lateral-mosfets.html

Not sure what the efficiency figures are, so I assume 50%.

 

[RampantAndroid]

My project is no longer active, but I was going to build an 8-channel amp using this:

http://www.diyaudio.com/forums/soli...amplifier-based-lme49830-lateral-mosfets.html

Not sure what the efficiency figures are, so I assume 50%.

Class A would be 50% or so. AB is better efficiency wise.

I'm quickly learning that solid state amps are just a PITA to build yourself. You might consider a class D - it'll be better for space and power reqs.

 

[Howard]

Class A would be 50% or so. AB is better efficiency wise.

I'm quickly learning that solid state amps are just a PITA to build yourself. You might consider a class D - it'll be better for space and power reqs.

Class A never reaches 50% - it's the theoretical maximum.

AB can get more than 50% but as I said, I don't know what it is, so 50% is a safe bet. Though after checking out a few references it seems the average efficiency for a Class AB amp is ~70%, so with 200W output I'd need to dissipate about 85W per chip.

Yep, I'm going Class D, pre-built modules, since it's cheaper and a hell of a lot less time-consuming. I built a 41Hz AMP6 a while ago and I'm not sure I want to do even that again.

 

[aigomorla]

howard if u want to watercool it let me know.

the best i can tell ya, is after you design it, send your layout in scale to a pal of mine.

He can then take a solid piece of copper or Alu, or whatever metal u want if u pay for it, and mill you a custom water block for the unit.

But a custom job will probably be the best route as he can work the water pathways in the most efficient manner then having to try to take parts which arent normally meant for your system and DYOing it.

I have people ive been working with for YEARS now that i can highly recommend.
This is one of his works i designed, and he built:

Its litterally the start of the evolution of full board blocks... <i could be sort of called a founding father for them>

My friends have access to lasers, waterjets, mills, computer cad stations... whatever you dream of, they can make it if your willing to pay for what u want.

 

[infoiltrator]

My feeling is find some "box" aluminum tubing and have someone heliarc end plate with tapped holes for fittings. Lap one? side for mounting transistors, mount wirh heat sink epoxy if you like. Or Tap holes and use locktite.I hope this is stationary, someone will have to do the size calculations, I would hope a used motorcycle radiator and computer fans would be sufficent. What pump at what rate is another question.
Might be tempted to eoxy directly to radiator, depending.