Calculation of Solar Heat Gain on Large Insulated Outdoor Vessel

[Tonylmiller]

I need to calculate the heat flux into a large, outdoor vessel, which is about 60 feet diameter and 40 feet tall, with a domed roof. I have all the dimensions and insulation details. The insulation is styrofoam with a reflective metal jacket. The vessel is about -20 F inside.

My question is, do I need to consider solar heating at all? If so, how to estimate it? I was thinking of using 100 F as the temperature of the outside of the shell (worst case), which would give me a temperature difference of 120 F. Should I raise the shell temperature a little to account for solar heating?

Thanks in advance.

Tony Miller
Cornerstone Engineering Group, p.c.

http://www.cegpc.com

 

[quark]

thread391-126948 If you are lucky enough, you can have TD2K put the excellent paper back on the site.

 

[Tonylmiller]

Thank you very much for your reply. I used the 3E heat transfer software and I think that will do very nicely.



Tony Miller
Cornerstone Engineering Group, p.c.

http://www.cegpc.com

 

[JKEngineer]

I did not see the referenced thread early enough to see that article, so I am responding blind with reference to its contents.

Solar heat load is certainly a factor in outdoor tanks. In fact, radiation is generally a factor - both heating and cooling, although the latter is probably not an issue at -20F, unless you are in a very cold place. (Although a clear night sky can have an equivalent temperature below -20F, and so may be a factor.) Also, both radiative transfer in general and solar heating specifically, will be reduced by the shiny metal jacket.

One reference would be ASHRAE handbooks. The Fundamentals volume deals with solar loading. I am less familiar with the other volumes, but they may also address your issues.

I have used FEA methods for this type of work in the past. It allows the calculations to reflect the time dependency of the solar loading.

HTH
Jack

Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering

http://www.KleinfeldTechnical.com

 

[Tonylmiller]

Thanks, Jack. I have looked at the ASHRAE handbooks and found them to be very valuable. The 3E software came out with a value that was within the expected range for an outdoor ammonia storage tank, so I feel good about the calculations.

Tony Miller
Cornerstone Engineering Group, p.c.

http://www.cegpc.com