Refrigeration Cycle in the Desalinator

heat flows to cold object 2. object is heated 3. heat flows to warm fluid 

So we consult a list of refrigerants in a handbook. Let s use a natural chemical as our refrigerant - ammonia.  

Let s arbitrarily specify that the ammonia vaporizes at —22°C. (We could have chosen any temperature less than —2°C.) However, ammonia boils at —33°C at 1 atm. How do we cause ammonia to boil instead at —22°C We increase the pressure of the ammonia. We consult a handbook and find that the saturation pressure of ammonia at —22°C is 25 psi. In the handbook we also read that the heat of vaporization at —22°C and 25 psi is A//yap = 574.9 Btu/lb. (Refrigeration data are usually in English units.) 

Note that in pure mks units the pressure should also be converted to Pascals (Pa) , /6895Pa, ,  

What flow rate of ammonia is needed to cool and partially freeze the seawater An energy balance on the slusher yields 

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