SES Utah
23-03-2010, 10:23 PM
I'm investigating potential blended refrigerants for a low temperature application. Lets say the evaporator is at atmospheric pressure, and the blend is 70% Argon, 15% Ethane, 15% Propane. (No smoking near the refrigerant!:confused:)
At this pressure, ethane will boil at 185 K and propane will boil at around 230 K. My thermodynamics is a little rusty so I'm wondering how much sensible heat is transfered into the refrigerant when one of the components is boiling ( and receiving a lot of latent heat). When the ethane starts boiling, I want to know how to determine how much sensible heat will be received compared to latent heat? Keep in mind the evaporator is part of a counter current heat exchanger, ideally with a 5-10C temperature difference between streams.
I've found whats called the Jakobs # which is a dimensionless number:
Ja = (Temp_Surface - Saturation_Temp ) / (Latent Heat Vaporization)
But I can't use this equation yet until I know the other streams temperature, which is depended on this stream!
At this pressure, ethane will boil at 185 K and propane will boil at around 230 K. My thermodynamics is a little rusty so I'm wondering how much sensible heat is transfered into the refrigerant when one of the components is boiling ( and receiving a lot of latent heat). When the ethane starts boiling, I want to know how to determine how much sensible heat will be received compared to latent heat? Keep in mind the evaporator is part of a counter current heat exchanger, ideally with a 5-10C temperature difference between streams.
I've found whats called the Jakobs # which is a dimensionless number:
Ja = (Temp_Surface - Saturation_Temp ) / (Latent Heat Vaporization)
But I can't use this equation yet until I know the other streams temperature, which is depended on this stream!