ASHRAE 62n Appendix G Efficiency Calculation

[rdmac]

Can anyone explain to me a little of the math of where the components to the G-2 equation come from? I understand we're calculating zone efficiencies here and I'm in the habit of considering efficiencies to be, generically, "output/input". Applying this interpretation of effiency in this case (eq G-2) it seems to me the zone efficiency would be the ratio of zone OA fraction (output) to the system OA fraction (input). I'm having trouble, though, visualizing the mathematical terms in the equation w/ their physical equivalents. Am I interpreting this eqn wrong?
Thanks,
rdmac

 

[Yorkman]

Rdmac, I don't know if you saw this publication or not but Trane has an engineering bulletin that explains the Standard 62n in pretty good detail and also lists 10 equations related to calculating the OSA rquirements under the new standard, including the G-2 equation your refering to. Trane Engineers Newsletter 33-1

http://www.trane.com/commercial/library/vol33_1/ADM_APN010_EN_040704.pdf

They also list the efficiency values for different diffuser/distrubution systems that the G-2 equation uses, as well as definitions of terms used in all 10 equations. Not sure this helps or not.

I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int./JCI

 

[rdmac]

Thanks Yorkman. I hadn't seen that article before. I just found a couple on the ASHRAE site that weren't very illustrative on the areas I had questions on. I downloaded the Trane whitepages on this though and they look to contain some good info. I'll repost here if there's anything left that isn't cleared up by the article.
thanks,
rdmac