1. SDB Demand-Controlled Ventilation: Preliminary Experiments Jay Taneja Software Defined Buildings Kickoff January 11 th, 2013

2. SDB Motivation SDBs can improve comfort Indoor environmental quality is multifaceted Buildings are often overventilated Demand-controlled ventilation (DCV) DCV benefits from BOSS Architecture – Incorporates non-BMS sensors and data – Transactions ensure safe system state – Communication throughout buildings

3. SDB DCV: Standards and Sensors ASHRAE 62.1 and CA Title 24 CO2 sensors Works best in enclosed spaces Target max of 800 ppm CO2

4. SDB Baseline Ventilation

5. SDB Extreme Efficiency Description Preliminary control effort to limit ventilation as much as possible Combines an occupancy model, outside air damper control sequence, and significant reductions in default airflow levels

6. SDB Extreme Efficiency Ventilation

7. SDB DCV Description Incorporate Google Calendar data Proportional control (airflow reflects CO2) Prior to meetings: Increase airflow During meetings: Modulate minimum to reflect CO2 concentration Not during meetings: Only respond if CO2 approaches 800 ppm threshold

8. SDB Demand-Controlled Ventilation

9. SDB Results Ventilation StrategyAvg. AirflowAvg. Ventilation Power Time > 800 ppm Baseline222.2 cfm0.1765 kW6h 3m (3.6%) Extreme Efficiency79.8 cfm0.0616 kW10h 57m (6.5%) DCV40.2 cfm0.0272 kW17m (0.2%) Caveats – Not all weeks created equal – Could increase airflow to reduce violations DCV offers a combination of energy savings and increased occupant comfort at minimal cost.

10. SDB Next Steps Expansion in SDH – 7/12 rooms with calendar data have sensors – DCF in cleanroom using motion sensors Grid potential as a supply-following load – Minimal ability to shed (positive slack) – Substantial ability to sink (negative slack) – Incorporate MPC for balancing objectives Integrate with BAS – write once, run anywhere

11. SDB Questions? Jay Taneja