Pipe length for tank for heating

[Mrepp]

I am specifying a heater for a new tank. My bright idea was to use the glycol available at 180 F and route it through the interior of the tank in 2" welded pipe and coil it until the appropriate BTU's are transferred. Considering the tank has no mixing, assuming the fluid is stagnant, how do I find the overall resistance. I know Q available from the glycol and the thermal conductivity of the fluid to be heated.

 

[TD2K]

It's essentially just a long exchanger.

Your heat transfer book will have natural covection correlations for the outside. For the inside, use a correlation for the inside of a tube.

Once you have the two heat transfer coefficients (the outside will be controlling), you can calculate the size of the coil you need.

 

[saxon]

Mrepp, There's on old Crane Valve Engineering Data Catalog VC-1900 (1976)that deals with the "Design of Pipe Coils for Heat Transfer". From your description, it sounds as if this is a liquid to liquid transfer in the free convection state. The Crane table approxmates the Overall Coeff. as follows:

1. typ. fluid water like, approx. U=25-60btu/hr/ft^2/deg.F

2. typ. fluid oil like, approx. U=5-10btu/hr/ft^2/deg.F

For other fluids interpolate.

Hope this helps.
saxon

 

[Mrepp]

Thanks for the info Saxon, and you summarize the condition correctly. I was looking for something other than a derivation for this, count on Crane to get you a nomograph or something "practical" considering time given to do our "art" these days. Do you remember what the range depended on?

 

[Mrepp]

Saxon-

I wouldn't mind having a copy of that for documentation. Mind sending a fax or snail mail?

Mrepp

 

[patrickraj]

An excellent worked out example is there in D.Q.Kern,Process heat transfer

 

[Mrepp]

Patrickraj,

Don't have that book. My fax is 907-273-3990 if you can spare a copy.

 

[patrickraj]

Mrepp (Chemical)
You are from which country.
Let me check which one will workout cheaper-Scaning or Fax.
Provide your MAIL ID

 

[Mrepp]

USA, micah.repp@nana-colt.com