Determine Glycol Outlet Temperature
Determine Glycol Outlet Temperature
(OP)
I am trying to find out what the outlet temperature of a 30% propylene glycol solution after it exchanges heat with air through a finned coil. Here goes the knowns I have:
Glycol Solution Mass/Volumetric Flow Rate (using minimal hydraulic flow of the pump)
Glycol entering temperature (set point on chiller)
Heat capacity of 30% propylene glycol
U Value for the Heat Exchange Coil
Air Mass/Volumetric Flow Rate (design)
Air Entering Temperature (design)
What I'm trying to calculate:
Air Exiting Temperature
Glycol Exiting Temperature
Haven't done a heat transfer calculation like this in a while. Can I these 2 equations equal:
(m)(Cp)(deltaT) = UA(deltaT log mean)
And solve using excel to get the 2 outlet temperatures (air and glycol)? Or is there another method for this type of heat transfer calculation?
Thanks in advance.
Glycol Solution Mass/Volumetric Flow Rate (using minimal hydraulic flow of the pump)
Glycol entering temperature (set point on chiller)
Heat capacity of 30% propylene glycol
U Value for the Heat Exchange Coil
Air Mass/Volumetric Flow Rate (design)
Air Entering Temperature (design)
What I'm trying to calculate:
Air Exiting Temperature
Glycol Exiting Temperature
Haven't done a heat transfer calculation like this in a while. Can I these 2 equations equal:
(m)(Cp)(deltaT) = UA(deltaT log mean)
And solve using excel to get the 2 outlet temperatures (air and glycol)? Or is there another method for this type of heat transfer calculation?
Thanks in advance.





RE: Determine Glycol Outlet Temperature
Your glycol exiting temperature is linked to the air exit temperature due to the conservation of energy. I've used Excel as you mentioned, vary the glycol outlet temperature, calculate the air outlet temperature (based on the amount of energy given up by the glycol) and then see if my UAdTlm equation gives me the same amount of energy transferred.
Are you calculating the individual heat transfer coefficients to come up with the overall U or do you have some other way of estimating the U overall?
RE: Determine Glycol Outlet Temperature
RE: Determine Glycol Outlet Temperature
Srfish - Can you show me on the internet where one of these charts are? I have the Process HEat Transfer Book from Donald Kern but can't find a chart in there.
Thanks.
RE: Determine Glycol Outlet Temperature
RE: Determine Glycol Outlet Temperature