Re: [EnergyPlus_Support] unit for carbon dioxide concentration

[Santiago Velez <santiagogvelez@xxxxxxxxx>]

According to what I understood from engineering reference Carbon dioxide concentration in ppm is by mass. 

So to convert it partial pressure calculate molar fraction , using the ppm output, and then calculate Partial pressure (Partial pressure = molar fraction x atmospheric pressure)    

Q. "The zone air density is used to convert the volumetric rate of carbon dioxide generation from user input into mass

generation rate [kg/s].The coefficient of 10*6 is used to make the units of carbon dioxide as ppm." (Engineering reference, p.43)

Hope this was helpful!

Santiago.

2012/5/12 andytamhk168 <andytamhk168@xxxxxxxxx>

 

From E+, the output of carbon dioxide is given in ppm. I would like to calculate the partial pressure of carbon dioxide in a room under atmospheric pressure.

My question is is the carbon dioxide concentration is in ppm by volume or ppm by mass?

I tried to figure out that from the E+ manual but I just could not have sure answer. Anyone knows?

If the carbon dioxide concentration is in ppm by volume, with 400ppm in a room, the partial pressure should be 400/10e6*totalpressure. Is this correct? Thank you.

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