How would I figure the needed pressure differential to freeze water inside a cooler using ambient air? I am assuming that the combined gas law would apply here and that the formula P1•V1/T1=P2•V2/T2 would provide the answer. My understanding is that by lowering the pressure I could effectively lower the temp as well. By this calculation I would need to reduce the air pressure from 1 bar to 313 milibar. Does this seem right on the math side? In an open system lowering the pressure should also lower the volume and therefore keep the temperature from dropping. Is this correct as well.
I would assume an ambient temp of 100 F.