Heat Loss From Pipes 3

[fwoody2000]

I have beeen trying to find a simple calculation to determine the heat lost from a pipe to the atmosphere. I can measure the surface temp of the pipe and the air temp, really I am strugling to determine the heat transfer coefficient. Any help would be appreciated. This is to be used as a method of determining the possible energy savings from insulating steam lines or replacing old damaged insulation.

 

[Montemayor]

fwoody2000:

Go to:

http://www.cheresources.com/software.shtml

There, you can download two, Free, Insulation Calculation Programs to help you with insulation calculations. The "Economic Thickness Calculator" will recommend the appropriate insulation thickness based on energy savings. The "Insulated Pipe Temperature Prediction Spreadsheet" will help you predict the temperature inside a pipe and linear heat loss.

 

[TD2K]

For horizontal pipes in air, Kern provides a correlation for the outside convection coefficient as hc = 0.5*(dT/do)^0.25 in US customary units.

Add in the radiation effect and that should be what you are looking for.

 

[TD2K]

I should have added, that's for natural convection of course. Throw in some wind, and the heat losses can go up by several times. The heat tracing books have charts in the past with multipliers for the effect of wind.

 

[CEM1]

Try 3E+

http://www.pipeinsulation.org/

http://www.eere.energy.gov/building...ame_menu=other_applications/pagename=subjects