[Stoves] Measuring hot surfaces with an infrared thermometer

[Crispin Pemberton-Pigott]

Dear Anil

 

It was interesting to hear his opinions on the calibration of the IR unit. There are instructions that come with the IR thermometers that pretty much are exactly as he describes the standard procedure. Because stove temperatures are pretty high (lots of red surfaces) I think his comments are relevant.

 

As he points out, the emissivity can change pretty quickly. With some materials the emissivity changes a lot with temperature. Not sure about water. It is much higher than is commonly assumed. What is the emissivity of superheated steam that results from combusting Hydrogen? That radiates from the tenuous flames that one appears to be looking through trying to get a reading from the opposite side of the combustion chamber – problems like that abound.

 

All interesting distractions for the new student! Like me!

Regards

Crispin

 

 

 

Dear Crispin,

 

We used this technique way back in early 1970s to measure solar collectors temperatures. The biggest drawback in these infrared systems is the number on emissivity. This keeps on fluctuating and is very sensitive to surface conditions.

 

All the best. Anil

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