Recent content by mecheng66

I'm looking for a formula to estimate the density of air (approx 20C at 60-100psi). Do the ideal gas laws still apply at these pressures?

Thanks for the ideas. IRStuff, the plan is to build about 15 or 20 of these and they'll go into different labs.

That's right, IRStuff, it doesn't have to be non-condensing. Even as I'm asking how to avoid condensation, I'm also trying to figure out a way to remove moisture, as you said. But it's looking pretty ugly and and I'm hoping a non-condensing solution will be easier... tbd Yorkman, good point...

Good idea, Yorkman, but it could be difficult: the device being cooled below ambient is mounted to the same circuit board that the other electronics are mounted to.

Thanks for all your suggestions. IRStuff, how does faster air help? Yorkman, the surface temperature of the cold device can be at least 20C below ambient. Any suggestions on the best way to dehumidify 120CFM air?

I'm tasked with cooling a set of electronics, something I've done many times, but this project has a new twist that I have no experience with: one of the devices has it's own proprietary cooling solution that brings it's temperature below ambient and we can't allow condensation to occur. The...

I've been through this before and developed a little spreadsheet with some success, but now I use heatsink designer instead -- it's simple but I like the way it draws the sink for you and you can learn a lot simply by trying different materials and sizes and running optimizations.

Not so, IRstuff. The datasheets might give a junction-to-case and but rarely specify junction-to-board, or die size, or package details, or anything else you need to know to figure out what's really going on.

I've been using Heatsinkdesigner for a couple of weeks now and it's pretty clear what the limits are. It basically tells you how a heat sink will perform in a wind tunnel, where you spec the tunnel size and the heat source details. This is useful but you have to understand how to apply it to...

Yes, I just found out about this one www.heatsinkdesigner.com. It's definitely worth a try.

I'm trying to figure out how to cool a circuit board with a lot of hot chips. We can supply pretty good airflow so I think the main thing is sizing heat sinks to see if it's feasible. After wading through heat sink catalogs I think we may need a custom design. I can find lots of info on...