Work out heat sink requirement?

iHearAll

iHearAll

Well-Known Member
no, you're skimping. there are indeed equations out for thermodynamics. You need to know how much heat in power (watts) to dissipate into a heatsink. The heatsink must be large enough to radiate the heat up and away from the chip and then radiate into the air all at a rate equal or better than the rate of heat coming from the heatsink. i imagine integrating would be the easiest math. but since math isnt your strong side you say then integrating would require a learning curve. so buy the ones recommended by the specialists who have done the math for you. cheers, sorry
 
J

JDMase

Well-Known Member
iHearAll said:
no, you're skimping. there are indeed equations out for thermodynamics. You need to know how much heat in power (watts) to dissipate into a heatsink. The heatsink must be large enough to radiate the heat up and away from the chip and then radiate into the air all at a rate equal or better than the rate of heat coming from the heatsink. i imagine integrating would be the easiest math. but since math isnt your strong side you say then integrating would require a learning curve. so buy the ones recommended by the specialists who have done the math for you. cheers, sorry
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I thought the style was more efficient than an extruded aluminium heat sink? (Says 20%) so I gathered I could use growmau5 dimensions of his 5.886" x 38" and then - 20% of the length to have acceptable cooling for said cobs. This is all hypothetical, I haven't looked into dimensions availabke for the style I linked to, but I thought of I could get an idea of how to work out those figures then I could reverse engineer the heat sink maths. :)
 
iHearAll

iHearAll

Well-Known Member
JDMase said:
I thought the style was more efficient than an extruded aluminium heat sink? (Says 20%) so I gathered I could use growmau5 dimensions of his 5.886" x 38" and then - 20% of the length to have acceptable cooling for said cobs. This is all hypothetical, I haven't looked into dimensions availabke for the style I linked to, but I thought of I could get an idea of how to work out those figures then I could reverse engineer the heat sink maths. :)
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well damn..... ok.....you might be on to something then. In my experience using, the heatsink can be large but if the heat isnt directed away appropriately then it tends to remain on the chip and it eventually cracks. i used car amplifier sinks that were more wide than tall and it lead to complications. so that being said, look at how long the pins are for those and even look at some of the chinese heatsinks for their 100w chips on ebay, they all are vertical since heat rises
 
J

JDMase

Well-Known Member
iHearAll said:
well damn..... ok.....you might be on to something then. In my experience using, the heatsink can be large but if the heat isnt directed away appropriately then it tends to remain on the chip and it eventually cracks. i used car amplifier sinks that were more wide than tall and it lead to complications. so that being said, look at how long the pins are for those and even look at some of the chinese heatsinks for their 100w chips on ebay, they all are vertical since heat rises
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Yeah I think you're right, if I were to go this route passive isn't an option, active would be just for the airflow aspect.

That being said, I would be running a circulation fan directly above it as I am doing with my HPS currently. So may not be an issue.

I think @CobKits is the cheapest for me to get the standard round pin fins shipped to the UK. Even cheaper than Europe in some cases. Which is crazy when you think about it.

I just fancied being different. Maybe I should take baby steps until I understand. :)
 
iHearAll

iHearAll

Well-Known Member
JDMase said:
Yeah I think you're right, if I were to go this route passive isn't an option, active would be just for the airflow aspect.

That being said, I would be running a circulation fan directly above it as I am doing with my HPS currently. So may not be an issue.

I think @CobKits is the cheapest for me to get the standard round pin fins shipped to the UK. Even cheaper than Europe in some cases. Which is crazy when you think about it.

I just fancied being different. Maybe I should take baby steps until I understand. :)
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good to try. im just saying ive cracked my share of ships by not doing calculations
 
DesertHydro

DesertHydro

Well-Known Member
Those round pin heat sinks have screw holes for mounting little PC fans or you can just have a lot of air circulation around them. From what I read the 120mm is good for 40-50 watts. I will be wiring up fans on all of mine just to keep things extra cool I think
 
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