temperature in a 40ft Container in the sun

[MarcoCello]

I am new in this forum and hope that I am at the right place with my question. I work in transportation and I am trying to create a new risk management for several transport laines.

The problem: I need do know how hot it can get in a metal 40ft container (in the worst case) about +-10 degrees(C). I have the outside temperature and average maximum global radiation figures for all cities that measure.

So absolute worst case: A (unrealistic I know, but still) black container stays in Dubai in summer, absolutely exposed to the sun.

Ambient temperature T=47(C)
Emissivity ε=0.9
Daily Value for global radiation: 7.5kWh/m2
Roof: A= 29.7m2
Side: 2x A=31.5m2
Side: 2x A=6.31m2
thickness of steel: 2mm
conductivity of steel: λ=50W/(m*K)

At first I would neglect any possible wind outside and air flow inside the container.

Unfortunately I am everything else than an expert in thermodynamics. Is there anyone who could help me with this? How hot could it get (and how long would it take to heat up to that temperature starting from the ambient temperature?

Best regards,
Tobias

 

[itsmoked]

thread391-464358

If you're serious about this you should get a couple of thermocouples, a container oriented north-south, and a digital multi meter that reads thermocouples.

Slam them in the door at the bottom middle and top. Read them a couple of times a day for a few days. Take good notes. Monitor the outside ambient with a fourth thermocouple. Note the wind.

You can do the math all you want but it will never be better than plus minus probably 15C.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

This might help:

https://www.tis-gdv.de/tis_e/containe/klima/klima-htm/

The expectation is that the solar load on a dark-colored container will be substantially higher than the air temperature. The cited article says for their case, the container was 25C warmer than the ambient air. Per traditional military requirements, storage temperature maximum is 71C, ostensibly, even with the highest ambient temperature specification of 49C.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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