Playing with Fire - Part 1

Propane (Photo credit: Wikipedia)

For most of last week I spent my days at the research farm burning propane.  Sounds awesome right?  It is, well, except for that one time I singed off an eyebrow*.  You may ask why I burning propane would be a part of getting a degree in animal nutrition.  It's really only important if you are an energeticist working with an indirect calorimetry system.

Did I loose you there?  An energeticist is a person (like me) who studies how energy is used and stored in the body.  Indirect calorimetry is simply a way of measuring how much energy is being used and what the source of that energy is.  It involves comparing the air that is breathed in to the air that is expired.  The technique can be used for any animal, even people.  Measuring the amount of oxygen disappearance and carbon dioxide appearance lets me calculate heat production, which we can equate to energy use.  

So, what does all this have to do with propane?  Well, by burning a known amount of propane I can calculate the amount of CO2 and O2 that should be consumped and used based on the complete combustion reaction**:

Propane (1-C3H8) + Oxygen (5-O2) --> Carbon Dioxide (3-CO2) + Water (4-H2O)

I compare these theoretical amounts to the amounts that my computer system records.  This is called a percent recovery and tells me if the equipment is functioning properly.

That's the basics of testing calorimetry equipment.  Any questions?  I'll talk about the test-burn itself in part 2.


*Wow did I look funny.  I'm much more careful about checking to see why the flame has gone out before relighting.  It might be that airflow has stopped and the propane has built up in the box. 

**  Gah, why won't blogger let me use subscripts?

Related articles

• It's not just how many calories, but what kind, study finds

  ---

• Metabolic rate, we all have one but what is it?

  ---