SDB

Demand-Controlled Ventilation: Preliminary

Experiments

Demand-Controlled Ventilation: Preliminary

ExperimentsJay Taneja

Software Defined Buildings KickoffJanuary 11th, 2013

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

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

SDB Baseline Ventilation

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

SDB Extreme Efficiency Ventilation

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

SDB Demand-Controlled Ventilation

SDB Results

Ventilation Strategy Avg. Airflow Avg. Ventilation Power

Time > 800 ppm

Baseline 222.2 cfm 0.1765 kW 6h 3m (3.6%)

Extreme Efficiency 79.8 cfm 0.0616 kW 10h 57m (6.5%)

DCV 40.2 cfm 0.0272 kW 17m (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.

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

SDB Questions?

Jay Taneja<taneja@cs.berkeley.edu>