Ammonia (NH3) was first isolated in the year 1761 by Joseph Priestly. While ammonia and carbon dioxide (CO2) were known as possible refrigerants, it was a matter of 73 years before anyone came up with the workable compression refrigeration cycle, which occurred in 1834.
A U.S. engineer, Jacob Perkins, first wrote about the closed compression refrigeration cycle. In that same year, a man by the name of Hoben, who apparently worked closely with Perkins, took out a U.S. patent. That patent outlined the Perkins system and featured the ammonia expansion valve. His patent covered the need for close control of the refrigerant into the evaporators.