Demand controlled ventilation

Demand Controlled Ventilation (DCV) is automatic adjustment of ventilation equipment according to occupant choice. DCV is a control method that modulates the volume exchange of fresh or outside air into an enclosed space by mechanical air conditioning equipment. Design engineers reference a codified standard when determining ventilation set points in order for sensors or time schedules and control loops to achieve indoor air quality.

There is a significant energy saving potential in rigorous outdoor air control. ^[1]

Common reference standards for ventilation:

• ISO ICS 91.140.30: Ventilation and air-conditioning systems
• ASHRAE 62.1 & 62.2: The standards for Ventilation and Indoor Air Quality

Examples of estimating occupancy

• Timed schedules
• Motion sensors (various technologies including: Audible sound, inaudible sound, infrared)^[2]
• Gas detection (CO2) In a survey on Norwegian schools, using CO₂ sensors for DCV was found to reduce energy consumption by 62% when compared with a constant air volume (CAV) ventilation system.^[3]
• Positive control gates
• Ticket sales
• Security equipment data share (including people counting video software)^[4][5]
• Inference from other system sensors/equipment

References

1. http://www1.eere.energy.gov/femp/pdfs/fta_co2.pdf
2. KMC Controls. (2013). Demand Control Ventilation Benefits for Your Building. Retrieved 25 March 2013, from http://www.kmccontrols.com/docs/DCV_Benefits_White_Paper_KMC_RevB.pdf
3. Mysen, M., Berntsen, S., Nafstad, P. & Schild, P. G. (2005). Occupancy Density and Benefits of Demand-controlled Ventilation in Norwegian Primary Schools. Energy and Buildings, 37(12), 1234–1240. Retrieved October 9, 2012.
4. University of California, Merced. "Occupancy Measurement, Modeling and Prediction for Energy Efficient Buildings". Retrieved 26 March 2013.
5. Lawrence Berkeley National Laboratory. "Carbon Dioxide Measurement & People Counting for Demand Controlled Ventilation". Retrieved 26 March 2013.