A popular passive cooling technique in laptops are heatpipes with heatsinks. Phase change cooling are very weight efficient, but the pipes used in laptops are not flexible. If there exists flexible pipes for this purpose then I think heatpipes would be a good way of distributing heat from the sensor to the magnesium body.
Some thermal cameras and microscope cameras have active TEC cooling of the sensor, but the heat from the TEC are normally removed by a heatsink and a fan. TECs are not very energy efficient even in optimal situations. Ordinary refrigerator technology are much more energy efficient in removing the heat. If that could be miniaturized enough, I think that might be an idea. Active cooling can give a problem with condensation. This could be solved by a relative air humidity sensor that stops cooling when the humidity approaches the dew point. A small pocket for a replaceable silica gel package inside the camera should make it possible to cool the sensor quite a lot before approaching the dew point. The purpose of cooling the sensor is not just to protect it from over heating, but thermal noise levels decreases a lot. This could make Pentax the leading camera for astro photography and general long exposure photography.
I don't believe Pentax will introduce active cooling, but its a nice daydream.
Another thing I thought about was that Pentax could move the shutter to the sensor assembly. The shutter could be built smaller because it doesn't have to cover the whole sensor shifted area. Though it would be more to move around so I don't know if it would be a good idea.
---------- Post added 02-23-16 at 01:58 AM ----------
Originally posted by monochrome I don't believe anyone has said officially (or if anyone ever will, officially). It is 36Mp, so it isn't the same sensor as the D750. Discussion here ( strongly supported) suggests it is an updated version of the IMX094, same base sensor as the D810. Reportedly Pentax has extensively customized / revised / improved it.
I hope their own
interview series will reveal how they improved it. Maybe someone will comment on that at CP+ too.