This is an interesting thread. We have some patents on heat exchangers
where I work. The best way to transfer heat is with a liquid. You can move the heat away quickly. Water has a very high specific heat and is a superb coolant. The use of
a water wetter will reduce surface tension and helps heat transfer from the substrate. I thought about water cooling amps for many years. Having an Auto and
motorcycle racing background. Using a large oil cooler or a radiator with a electric
water pump . Never really set anything up or even got the parts together. I have two A-75's and a ZEN with a Pi filter supply never really needed the water cooling.
I dont mind fans if they are on the quiet side.( I listen on the loud side) it is a great
idea in the summer if you mount the radiator outside and dump the heat out of the AC.
where I work. The best way to transfer heat is with a liquid. You can move the heat away quickly. Water has a very high specific heat and is a superb coolant. The use of
a water wetter will reduce surface tension and helps heat transfer from the substrate. I thought about water cooling amps for many years. Having an Auto and
motorcycle racing background. Using a large oil cooler or a radiator with a electric
water pump . Never really set anything up or even got the parts together. I have two A-75's and a ZEN with a Pi filter supply never really needed the water cooling.
I dont mind fans if they are on the quiet side.( I listen on the loud side) it is a great
idea in the summer if you mount the radiator outside and dump the heat out of the AC.
I know the feeling, chase the details and lose focus on the big picture...
For reference the Stefan-Boltzmann constant (the @) is:
5.670 400(40)×10−8 W/(m^2·K^4)
For conduction, thermal conductivities are in the range of:
0.025 W/m.K for Air
400 W/m.K for Copper
Convection is much more of a pain. The h value is a function of things like viscosity, velocities, differential densities, etc.
However the above proves the point, the 10^-8 on the Stefan-Boltzmann constant means that while dT is smallish, heat transfer is small, as you get up to dT > 100, radiation rapidly becomes significant. And for all the surface area of fins, you'd still model a heatsink as maybe 4 sides (+20-30% for the edges...) of a solid rectangular prism...
For reference the Stefan-Boltzmann constant (the @) is:
5.670 400(40)×10−8 W/(m^2·K^4)
For conduction, thermal conductivities are in the range of:
0.025 W/m.K for Air
400 W/m.K for Copper
Convection is much more of a pain. The h value is a function of things like viscosity, velocities, differential densities, etc.
However the above proves the point, the 10^-8 on the Stefan-Boltzmann constant means that while dT is smallish, heat transfer is small, as you get up to dT > 100, radiation rapidly becomes significant. And for all the surface area of fins, you'd still model a heatsink as maybe 4 sides (+20-30% for the edges...) of a solid rectangular prism...
It seems this thread has covered quite a bit 
From the original Firezab post asking about using a putor cooling system for his Zen amp, to Grey's adventurous system, to the last several posts inviting Stefan and Boltzmann to the party 
are they members here?
Anyway, along the lines of the original thread starter, I have indulged in the putor accesories for some cooling too. Only while prototyping though. I, like others, find the traditional heatsink availability and cost difficult to swallow in the size/quantity this hobby requires. And also like others, I want to avoid a fan. It would also be nice to develope a safe reliable system such that you won't burn up the amp, or your house, or flood the listening room, if something did fail
We seem to have agreed on the same 'ol standard component materials to a large degree, ie; water is likely the best fluid to use, materials such as copper or Aluminum are the easily available metals to use, there are untold numbers of liquid to air exchangers already in existance and even availbale to recycle! But again, like others, that is as far as I've gone with this idea too.
I would like to find some new ideas reagarding simple inexpensive, easily avalable hardware. I could make some larger than (Video Processor) copper blocks like I have, but not everyone can. There must be some water block manifold thingy in the plumbing world somewhere that would be perfect to mount your transistors on? It would already have standard style fittings for inlet and outlet water connections, without soldering copper together??? What would that be For a pump isn't it possible to make some sort of verticle column for the water to flow automatically thru Maybe you don't even need the pump and radiator. But, a radiator like has mostly been suggested, has it's fins to close together for unassisted air flow. Convection air flow needs a low resistance path with more openess than a typical forced air style radiator. It would also be good if this device did not look so much like an auto radiator mounted to the back of my equipment... But what?
From the original Firezab post asking about using a putor cooling system for his Zen amp, to Grey's adventurous system, to the last several posts inviting Stefan and Boltzmann to the party are they members here? Anyway, along the lines of the original thread starter, I have indulged in the putor accesories for some cooling too. Only while prototyping though. I, like others, find the traditional heatsink availability and cost difficult to swallow in the size/quantity this hobby requires. And also like others, I want to avoid a fan. It would also be nice to develope a safe reliable system such that you won't burn up the amp, or your house, or flood the listening room, if something did fail
We seem to have agreed on the same 'ol standard component materials to a large degree, ie; water is likely the best fluid to use, materials such as copper or Aluminum are the easily available metals to use, there are untold numbers of liquid to air exchangers already in existance and even availbale to recycle! But again, like others, that is as far as I've gone with this idea too.
I would like to find some new ideas reagarding simple inexpensive, easily avalable hardware. I could make some larger than (Video Processor) copper blocks like I have, but not everyone can. There must be some water block manifold thingy in the plumbing world somewhere that would be perfect to mount your transistors on? It would already have standard style fittings for inlet and outlet water connections, without soldering copper together??? What would that be
For a pump isn't it possible to make some sort of verticle column for the water to flow automatically thru Maybe you don't even need the pump and radiator. But, a radiator like has mostly been suggested, has it's fins to close together for unassisted air flow. Convection air flow needs a low resistance path with more openess than a typical forced air style radiator. It would also be good if this device did not look so much like an auto radiator mounted to the back of my equipment... But what?
If I remember correctly (been 20 years since my advance Heat Transfer classes) h for stagnant air is the pain. Add moving air (Laminar flow and Turbulent flow) and the h is a bit more predictable and accurate.
Ah yes, I remember trying to calculate those Film Coefficients for convective heat transfer ...Prandtl, Grasshof, Reynolds numbers...all coming back to me....the tables, and equations....
Funny, until now, the only things I fondly remember about college were the parties, the dope, and graduation.
LOL...good one.
Had they been alive today (they are dead, no?) one would have to wonder how they would cool their transistors.
I really don't have a problem with a fan. The Krell KSA series had fans before they went with monster heat sinks.
You really wanna get crafty? Get one of those humidifiers directed at your heat sink fins. Combination forced air and heat of vaporization will surely get you some nice cooling, and your sinus will love you for it (if you live in a dry climate like me)
As for parts, there are often water blocks on ebay from lytron and the like. I think there is a guy right now that has a bunch with TO3 holes already drilled. There are almost always the type used in beer/soda coolers (they are a bit larger, and so have more thermal mass).
Although I have never made one, making a water block from scrap copper plate and some tubing can't be all that impossible. One thing about copper- it does solder well.
Although I have never made one, making a water block from scrap copper plate and some tubing can't be all that impossible. One thing about copper- it does solder well.
flg said:It seems this thread has covered quite a bit
Anyway, along the lines of the original thread starter, I have indulged in the putor accesories for some cooling too. Only while prototyping though. I, like others, find the traditional heatsink availability and cost difficult to swallow in the size/quantity this hobby requires. And also like others, I want to avoid a fan. It would also be nice to develope a safe reliable system such that you won't burn up the amp, or your house, or flood the listening room, if something did fail
We seem to have agreed on the same 'ol standard component materials to a large degree, ie; water is likely the best fluid to use, materials such as copper or Aluminum are the easily available metals to use, there are untold numbers of liquid to air exchangers already in existance and even availbale to recycle! But again, like others, that is as far as I've gone with this idea too.
I would like to find some new ideas reagarding simple inexpensive, easily avalable hardware. I could make some larger than (Video Processor) copper blocks like I have, but not everyone can. There must be some water block manifold thingy in the plumbing world somewhere that would be perfect to mount your transistors on? It would already have standard style fittings for inlet and outlet water connections, without soldering copper together??? What would that be
Not that I would ever build such a thing, but if you really wan't to get rid of a lot of heat using water cooling without the complication of fans and radiators, just circulate the water from a huge storage tank.
Thats still a finite sink for your heat though, if you can discharge it to atmosphere, its infinite (for most intents and purposes).
flg: something like this would allow natural convection:
In theory, you are right, it should be possible to set up an arrangement that would flow without a pump. How well it would circulate is the question. Essentially its a natural convection problem, with some added friction losses. The problem is that the density of water only changes by 4% between 0 and 100 C, which means minimal buoyancy.
You could try an alcohol that is liquid at room temperature but gas at a selected operating temperature...
flg: something like this would allow natural convection:
In theory, you are right, it should be possible to set up an arrangement that would flow without a pump. How well it would circulate is the question. Essentially its a natural convection problem, with some added friction losses. The problem is that the density of water only changes by 4% between 0 and 100 C, which means minimal buoyancy.
You could try an alcohol that is liquid at room temperature but gas at a selected operating temperature...
G.Kleinschmidt said:
Beat you to it, mate.
Unfortunately, the 75' SS braided hydraulic hoses with pressed-on fast connectors and a Danfuss central heating waterpump are lying idle, after the hemorrhoid-like exit of the Pass Monster amp project.
(same goes for a quartet of silly size toroidal transformers and two heat plates)
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It's called a thermo siphon. A temperature imbalance would surely affect flow and ultimately heat transfer.
All this to get around a fan? Or are you trying to make a 500wpc Class A amp? I can appreciate "Rube Goldburg"-ing this cooling thing, but you all seem serious.
Jacco - I didn't know the Dutch had a sense of Humor...
I was pointing at the head of the municipal construction department who does not issue a building permit for covering my pool, i'd like to use it in winter as well.
It was not a joke, a pool requires an enormous amount of energy for filtering and heating on a yearly basis.
The hoses which are visible in the water are for the heating, around 2,5 mwh/yr.
(what is a joke is that i live at walking distance from the beach)
Maybe the Monster will resurect, G Rollins' tube front end and the output stage are there and i've got 2 Jensen output transformers.
thermal insulation cover=>
It was not a joke, a pool requires an enormous amount of energy for filtering and heating on a yearly basis.
The hoses which are visible in the water are for the heating, around 2,5 mwh/yr.
(what is a joke is that i live at walking distance from the beach)
Maybe the Monster will resurect, G Rollins' tube front end and the output stage are there and i've got 2 Jensen output transformers.
thermal insulation cover=>
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