Yes, I was referring to the massive overhaul of part physics regarding heating, conduction, radiation and convection. Thus far I'm liking the heating system, but the lack of dedicated radiators is rather depressing. Solar panels are virtually useless as far as I can tell, the most significant difference seems to come to having a part directly attached to the heaviest item available. I've been testing mainsails and have found that they overheat significantly unless attached to a fuel tank, an XL girder is fairly good at taking heat from the engine but it overheats after a few minutes, adding more girders to the girder lowers it's temperature but not significantly enough to make a difference to the engine. For analysis of the effect fuel tanks have see this image:
This is after about 20 minutes of burning.
The setup is this, the mainsail attached to the S3-7200 tank is the control, with mainsail putting out 180 units of heat attached to a 4.5 ton tank. The mainsail itself has a thermal mass of 4800, the tank has thermal mass of 66,871.
Right of it is a mainsail attached to an X200-8, with weight of only .5 tons this has a tenth the fuel and thermal mass, the exact number is 7430.
Behind the control is the same S3-7200 tank but with gigantor panels attached, there are 24 panels, each weighs .35 tons for a combined mass of 8.4 tons, and has a thermal mass of 540, total of 12,960. For reference this is a 19% increase on the thermal mass of the tank it is attached to.
Lastly on the back right is a mainsail attached to 2 S3-7200 tanks, I previously tested a S3-14400 and found it had exactly the same properties as 2 stacked 7200's. The tank weighs 9 tons and has thermal mass of 133,743, double the mass and double the thermal mass of the control.
The engine attached to the X200-8 slowly crept up to 1900 degrees, when it hit 1950 I throttled it back to see what difference that made, after hitting 74.5% the temperature slowly dropped to 1927.7 degrees.
We notice that compared to the control there is a 130 degree difference in the engine temp compared to the one with solar panels, the tank itself displays a similar temperature difference, note however that this is with twice the weight in panels as the fuel tank itself weighs.
Finally we see the engine attached to the double tank is 260 degrees cooler.
About half an hour after the screen shot the control engine hit 1500 degrees, testing is still ongoing but I'm very confidant that it will reach equilibrium well below 2000 degrees without needing to throttle back. Interestingly, both rear engines were barely 1000 degrees, but the one with solar panels was actually slightly cooler than the double tank setup.