Hi,
I am working on an energy model for core and shell office building. To reduce the reheat energy the mechanical designer planning to reduce the minimum stop for fan-powered boxes. If we showed in the “Minimum IAQ Performance Calculator” that the fan-powered box minimum stop is 20% of peak primary airflow, should we model that percentage in the proposed and baseline models? or only in the proposed model and keep the baseline model at 30% as required by G3.1.3.14?
Thank you,
Tyler Thumma
7GroupLEEDuser Expert
60 thumbs up
December 20, 2019 - 11:09 am
Only the Proposed case would get modeled with the reduced minimum stop. The Baseline should always be modeled with a minimum of 30%.
Saif Alsaeed
December 20, 2019 - 11:28 am
Thanks Tyler, what about the outside air flow rates should they be still modeled the same in both proposed and baseline according to G3.1.2.6 ? or a different calculation should be done for the baseline because the minimum stop plays a role in determining the outside air flow rate?
Tyler Thumma
7GroupLEEDuser Expert
60 thumbs up
December 20, 2019 - 11:48 am
Beginning in ASHRAE 90.1-2010 the outside air flow rates are more typically not modeled the same because of exception c to G3.1.2.6, since most designs include varying degrees of over-ventilation relative to the code minimum. However, the "amount required by the rating authority or building official" would be the code minimum as calculated for the Proposed design. Therefore, a separate calculation of the Baseline code minimum outside air would not be required.
Saif Alsaeed
December 20, 2019 - 12:02 pm
Thank you,