eQuesters:
To comply with 90.1-2007 System Type 7, do I need to have supplemental
heat with baseboards if I have it in the proposed system? Or, is it
allowable to meet nighttime heating demands by cycling fans during
unoccupied hours to meet nighttime setback temperature?
In the proposed model during unoccupied periods I have fans OFF with
baseboards providing supplemental heat.
Thanks in advance for your feedback.
Jonathan R. Smith AIA LEED(r)AP
My $ 0.02
You should cycle your fans in the baseline.
Vikram Sami, LEED AP
Jonathan,
ASHRAE Standard 90.1-2007, Appendix G. section G3.1.2.4 requires fan
cycling to meet heating and cooling loads during unoccupied hours.
Appendix G. does not provide guidance on the use of baseboard heating.
My approach has been to always leave baseboards out of the baseline
building design.
There is a discussion on the Bldg-Sim list today about ventilation rates
per G3.1.2.5. There seem to be as many interpretations of this section
as there are energy modelers. In the case of a proposed fan system that
shuts off at night, I would model the baseline with a MIN-AIR-SCH, set
to 0 during unoccupied hours, so that no ventilation is provided during
nighttime fan cycling.
Regards,
William Bishop, PE, BEMP, LEED(r) AP
We just got a review comment from GBCI stating to verify that we set our
outside air to be shut off during night cycling in the baseline. So at
least one reviewer interprets that requirement. We?ve always done it that
way, but a lot of packaged equipment out there doesn?t actually have that
capability.