ELI5: How do Single Pressure Absorption Refrigeration Units Work? explainlikeimfive

I've read the wikipedia article on how they work, but I just cant understand how the evaporator functions without some sort of one way valve or something...

The article establishes that the ammonia is liquid at room temperature with the pressure used, so why does it evaporate?

Submitted September 25, 2015 at 02:57AM by Siggy_23 http://ift.tt/1L9gSia explainlikeimfive