Direct Die Cooling is usually based around using the compressor/evaporator/condenser/oil separator from a fridge or A/C unit, and moving it from cooling 5000 square foot room to a chip less than 1 square foot in size. Average temps are sub -100C. I am currently working on a dual stage one. Eg: One cools the other, then that cools the chip. But the gas used is expensive and hard to obtain, but I did have fun tearing down some fridges. 😃 It will be a while before I finish due to lack of time, and tools. 😕