Well John, you're at least half right. When you apply power to a stirling engine to run the normal cycle in reverse (power piston now leads the displacer by 90 degrees), the exposed cylinder (which is normally heated) now removes heat from the air around it. Please don't ask me how this works. These stirling 'cryocoolers' and are now used by the thousands in aerospace, defence, medicine, and science. They will cool down to extremely low temperatures: stirling freezers routinely keep temps at 100 below zero and can even reach much lower temps required for superconductivity. They have few moving parts, are maintenance free, don't use refrigerants, and are nearly silent.