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Question on Black Globe Temperature?

Question on Black Globe Temperature?

Question on Black Globe Temperature?

(OP)
I understand what it is and how it is typicalyl measured.  However I am not familiar with typical values are in correspondence with say the dry bulb temperature.

I am looking for a table with typical vaues that I could use to do some approximate analysis.

For example is there any data out there that would give me some black globe temperature values on say a day where it is 80F dry bulb and no air movment on a sunny day?

Anything would be helpful.  I just want to get a feel for what kind of increase above the dry bulb temperature I am looking at for the black globe temperature.

RE: Question on Black Globe Temperature?

With my home made black globe thermometer, on my desk (insulated on a styrofoam cup).

Globe temps are about 1 F higher than air DB temp.

RE: Question on Black Globe Temperature?

(OP)
That might be true but is your black globe in direct sunlight?  If it is on your desk I assuem it could still be gettign sunlight but not a tremendous amount.  If it were outside I would think it owuld get much hotter.

RE: Question on Black Globe Temperature?

Full glass wall with southern exposure, but not direct sunlight.

RE: Question on Black Globe Temperature?

MJ,

Did you ever find an answer to your black globe question?  I've hunted around, but have yet to find anything that describes any equations involving the interior of a black globe.

Do you have any public references you can point to?

Thanks...

TTFN

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RE: Question on Black Globe Temperature?

IR,

No, I never got any replies to my questions here or elsewhere.

ASHRAE Fundamentals contains a few paragraphs about the black globe in chapter 14 in the discussion of Mean Radiant Temperature.

I am led to believe that ASHRAE Standard 55-2004 has some info as well.  I've ordered a copy, but it hasn't shown up yet.

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