Forum discussion
NC-2009 EAp2: Minimum Energy Performance
Dear All,
According to 90.1, the HVAC system shall follow the design for proposed case. I wonder what if the HVAC engineer under-sizes the cooling capacity. Certainly, it would lead to a high unmet hours. What approach shall we take to fix that?
Thanks
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
February 20, 2013 - 11:56 am
Install additional cooling capacity.
Yoyo Shek
Allied Environmental Consultants Limited4 thumbs up
February 20, 2013 - 8:53 pm
Thanks Marcus!
What if the reality does not allow to change the design, such as the equipment has been ordered or etc.
So does it mean the energy modeler has to increase the cooling capacity of chiller to settle the unmet hour (While keeping the efficiency unchanged)?
Jean Marais
b.i.g. Bechtold DesignBuilder Expert832 thumbs up
February 21, 2013 - 2:11 am
yes. the reasoning from ashrae is that if the unmet load hours exceed 300 hrs, then the building is under conditioned and in the future the users will have more capacity built in to create a comfortable space.
Yoyo Shek
Allied Environmental Consultants Limited4 thumbs up
February 21, 2013 - 11:44 pm
Thanks Iean!