Item ID: 53
Using Lighting Occupancy Sensors in Offices to Control HVAC
Occupancy Sensors: Controlling HVAC & Lighting Systems vs. Controlling Lighting Systems Only
Occupancy sensors compatible with lighting and HVAC systems and capable of managing the HVAC operations within a space depending on occupancy.
Terminal boxes usually supply a single zone in a large office building. Each terminal box has a minimum flow rate that is often set at the design occupancy for the zone. Occupancy sensors can detect when a zone is unoccupied and can set the ventilation flow rate to zero when no occupants are in the zone (Zhang 2013). Spaces that benefit from having occupancy sensors that turn the lights off when unoccupied could also benefit from having the sensor communicate with the HVAC system for the zone, which would turn off or turn down ventilation air flows when the zone is unoccupied. Some spaces can also allow temperatures to naturally rise or drop, but the potential impact on occupant comfort and productivity needs to be taken into consideration. A single occupancy sensor can do double-duty by controlling both systems. Large spaces that are lightly and intermittently used, such as gymnasiums, theaters, classrooms, and conference rooms, offer the best opportunities for energy savings, which may be as high as 60% of ventilation system energy use. Hotel rooms are another appropriate application, demonstrating savings from 20% to 40%. Greater energy savings (DCV saves a smaller percentage of a much larger baseline energy use) can be achieved with demand-controlled ventilation (see record #166 in this database).These controls can be effectively used in spaces utilizing ductless heat pumps, which tend to have smaller zones.
This technology is most easily incorporated into new construction because it requires a way for the lighting and HVAC systems to communicate with each other, which can most easily be achieved in new construction. For retrofit applications, consider using wireless sensors, which are rapidly becoming more available, more reliable, easier to use and set up, and less expensive.
Energy Savings: 36%
Energy Savings Rating:
Extensive Assessment What's this?
|1||Concept not validated||Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.|
|2||Concept validated:||An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.|
|3||Limited assessment||An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline. |
|4||Extensive assessment||Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions. |
|5||Comprehensive analysis||Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.|
|6||Approved measure||Protocols for technology application are established and approved.|