Let’s see here…
I would say so yes. You don’t want it to lower the speed too quickly though as you’re getting a super annoying varying fan noise. I’d take a static fan at a higher noise level rather than something that can’t make up its mind any day.
Well, just don’t leave it in the sun, that will sure make it unhappy (but who would attempt to use a projector in sunlight). But if it’s still over 35C when the sun is down and the projector is turned on then sure, you’d have less headroom than if it’s used in 20C ambient, but the difference really isn’t that big. I’m more worried about elevated humidity causing corrosion and other bad stuff.
Yes and no. You’d choose between component longevity and low noise depending on how the adaptive algorithm is tuned. Hopefully the PPM fixed speeds should be tuned for the maximum ambient temperature specified, which means that an adaptive speed really wouldn’t drastically improve the life as long as you’re operating the PPM below maximum allowed ambient temperature.
If you look at the very informative datasheet for the DLP230NP DMD around page 24 the expected life is highly dependent on duty cycle which in turn makes it content dependent which will make it very difficult to predict. The DMD will definitely have a longer expected life if it’s kept cooler and exposed to less intense light.
The quoted 30k+ hours for the LEDs is IMHO a fantasy number. Yes most likely the LEDs will still light up at 30k hours, but they will emit nowhere near the luminous flux they initially did and the color balance will likely be quite off due to the fact that the different color LEDs will degrade at different rates.
The good thing about this being a discrete RGB(B) light engine is that the relative duty cycle between RG and B is programmable so this could in theory be compensated for to a degree. In the color wheel based projectors with UHP lamps you would always lose the red at the end of usable lamp life, but the color wheel sectors are static so you’re stuck with less red until the lamp fails altogether. I’ve used up tens of UHP lamps in color wheel projectors and the annoying part is that color balance is changing fairly rapidly the first few hours in a new bulb and also in the last 25% (500 hours or so) of lamp life. With LEDs this is a much slower process.
My guess is that the DMD will last longer than the LEDs will, and most likely something else will have failed before the LEDs do (I’m thinking flash memories and definitely the battery). You also have to consider the likelihood that the projector might become physically damaged in some way before the electronics fails due to age, as this is a portable unit.