We have a 3,000 SF building which will be occupied intermittently by the client/owner.
One small part of the building is being continuously maintained at occupied temperatures, a second part of the building will be occupied intermittently by up to 10 individuals up to 8 hours per week, and the third part of the building will be occupied for assembly functions for 70 occupants 3 to 4 times a year.
Space temperatures can be separately regulated and controlled between the first part and the second and third parts.
For the second and third portions of the building, we propose to control the HVAC system and its set points by motion sensors and CO2 sensors for ventilation air. Specifically, motion sensors will change the interior set points from unoccupied to occupied. We propose to model the occupancy as 40 hours-per-week in our base case, and limited intermittent occupancy in our proposed case, where the lighting and spaces temperatures are controlled by motion sensors ventilation air will be proportional to occupancy at 15 cfm/person, or the minimum required by the exhaust systems. This modeling technique seems appropriate for a building that without the motion sensors (base case) would be controlled by a weekly programmable thermostat specifically Monday thru Friday for 8+ hours per week alone.
Is this approach acceptable to LEED v.3.0 NC EA Prerequisite 2 and EA Credit 1? If not, please advise: how should we model these occupancy/temperature profiles in the base and proposed case?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
September 19, 2011 - 12:08 pm
Temperatures and schedules must be identical according to Appendix G. Any variation in either between the models would need to follow the exceptional calculation method.