Heat Load From Solar Load

You've virtually answered your own question. So why not carry on your research yourself!

Any specification using words like "shelterized" is likely to have been written by bureaucrats rather than engineers. No mention was given of thermal loads within the shelter, such as electrical/electronic/chemical reaction equipment; nor air infiltration. The R3.6 value is surprisingly low, but it may be necessitated by inside vs outside dimensional limits.

At a rule-of-thumb level, solar effect is sometime considered as adding something like 10-15°F to the simple air temperature difference. On that basis, the solar load per ft² would be (15 + 110 - 85°F)/3.6 ≈ 11.1 Btu/h. I don't yet see where the 355 Bth/h-ft² figure comes from.

This is so weird that I will try to review it again. (Just in case I've blown a decimal point placement.)

In the tropics (in Bangalore where I live) peak insolation (Mid-day, summer, normal to the surface) is about 800w/sq.mtr. Even this equals only 253 btu/hr.sq.ft. 355 Bth/h-ft² appears to be high.

bioramani

The 355 Bth/h-ft² is dictated by the customer in their requirements specification.

There are equipment heat loads (about 15000 BTU) that would presumably be added to the solar load that would contribute to sizing an HVAC system.

To try to add to what others have posted - what are you using the Stefan Boltzmann constant for, the heat lost from the shelter? You don't need it for the heat input from the sun. 355 BTU/ft²/hr = 1.12 kW/m², is about right for maximum heat from the sun. The solar constant is ~ 1.4 kW/m², above the atmosphere. 800 watt/m² in #3 seems a bit low but could be right.

Is the R value 3.6, presumably °F*ft²/(BTU/hr) just based on the conductivity of the walls, or is it an overall factor allowing for convection from inside air to inside wall surface, and outside wall surface to outside air? Assuming the latter (worse case) I make conduction heat loss with ΔT 40K about 28kW.

Cheers.........Codey

This may help? http://www.globalspec.com/featuredProducts/detail?ExhibitId=155654&uid=-1418233072&frmtrk=alert bioramani