I need some help with a thermal question... I am trying to design an aluminium die casting. It is for an enclosure but will have a PCB screwed to its inside face. The outside face must act as a heatsink. I have two questions: 1) If I need to dissipate 20W of heat from that PCB, what should the heatsink “fin†dimensions be like (thickness ad height), and what should their spacing be? I need to ensure optimal performance, but don’t know how to best to design a heatsink. Is there a standard formula or standard rules for designing such a thing? 2) Secondly, I have seen heatsinks that have “pins†instead of “finsâ€. How much better is the performance of pins compared to fins? I presume pins are better because they have more surface area? How could I calculate the geometry of the pins to ensure optimal performance? Any help appreciated.
Its for the outdoors so there will be some airflow but I want to design for zero airflow to be considering the worst situation possible. I already design a heatsink - it seems to work ok but I would still like an answer to my original question because maybe I can optimise it.,
Been away a bit, but try this.... http://www.frigprim.com/online/natconv_heatsink.html Might get you close. -mark
