Hi all, I've been looking for an answer to this for a while now but I can't explain to Google what I want to know. Hope I have better luck here. I'm an aerospace engineer working on a satellite project. In particular I'm currently working on the thermal analysis and I need to model up each of the systems as a heat source. My question: If I don't have the exact efficiency of each of the electrical systems, what is a good value to use? Obviously the input power can't all be converted to heat, but some is. For example, say the main onboard computer uses 1W of power, would it be a valid assumption to model it as a 0.6W heat source? I really have little to no idea and searching Google I can only find exact methods for each component on the board, or how to remove heat, or conduction through the plane. Not useful. Cheers!