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How does Ammonia achieve -70°C in atmospheric pressure?
R717NOVAH:
I can witness liquid NH3 achieving sub 'boiling point' temperatures by simpling removing a thermocouple from a container of liquid, typically around -40 to -60°C.
I see that as the Ammonia evaporates energy is lost from the liquid droplets and I would imagine a loss in density.
With the exception of mathematical explanations from the works of Geoffrey D. Kaiser & Richard F. Griffiths, I am yet to find an explanation that hits home of how this occurs other than terms like entrained air and adiabatic volumetric expansion, partial pressures etc. I would like to find some visualisation of what is exactly going on in this process.
AWK:
Look at the ammonia phase diagram.
R717NOVAH:
--- Quote from: AWK on September 13, 2020, 05:55:40 AM ---Look at the ammonia phase diagram.
--- End quote ---
The P/T of Ammonia at equilibrium indicates - 33°C am I missing something, how does it drop below this point without a drop in pressure?
AWK:
You have to cool the ammonia - otherwise, the temperature will not drop. At a pressure of 1 Atm. liquid ammonia exists in the temperature range of ~-75 to -33°C.
R717NOVAH:
--- Quote from: AWK on September 13, 2020, 03:10:29 PM ---You have to cool the ammonia - otherwise, the temperature will not drop. At a pressure of 1 Atm. liquid ammonia exists in the temperature range of ~-75 to -33°C.
--- End quote ---
This is the object of my question - how is the Ammonia being cooled below -33°C ?
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