Self-Powered Lighting Controls
Light Switches and Occupancy Sensors: Wireless vs. Wired
Wireless occupancy sensors and other switches that harvest energy from the environment so that batteries or expensive wiring, making it easier to add more switches and increase local lighting control.
Item ID: 599
Residential, Commercial, Industrial
Lighting--Sensors & Controls
Technical Advisory Group: 2014 Residential Building TAG (#10)
Average TAG Rating: 2.73 out of 5
TAG Ranking Date: 04/10/2014
A self-powered and wireless occupancy sensor eliminates the need to run wire to occupancy sensor locations in both new and retrofit applications. Battery use is not necessary for these self-powered switches as, once activated, the occupancy sensor is powered by solar cells that harvest room light. These sensors and switches are compatible with incandescent, fluorescent and other low-voltage light sources and are suitable for offices, conference rooms, break rooms, classrooms, bathrooms, and other intermittently occupied areas. A receiver responds to signals from the wireless occupancy sensor, automatically shutting off lights when the room is vacant. The wall switches convert the energy of the button push into the power needed to send a signal to operate the lights.
While energy savings are small, savings in installation and maintenance costs can be significant. From an energy savings standpoint, self-powered sensors are really an enabling technology for sensor installation. It will be assumed that a 9-Volt Alkaline battery would be capable of driving a wireless occupancy sensor for one year. This type of battery has an energy storage of about 5.1 Watt-hours or the ability to provide an energy consumption of 0.0051 kWh/year (9 volt x 0.565 mA for one hour).
Baseline Description: Sensor with Battery Power
Baseline Energy Use: 5.1 kWh per year per thousand sensors
5.1 kWh/year per 1,000 conventional sensors.
Manufacturer's Energy Savings Claims:
Currently no data available.
Best Estimate of Energy Savings:
"Typical" Savings: 99%
A self-powered sensor completely eliminates the requirement for battery or the in-facility distribution system.
Energy Use of Emerging Technology:
.1 kWh per thousand sensors per year
Energy Use of an Emerging Technology is based upon the following algorithm.
Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
Potential number of units replaced by this technology:
Since the baseline is expressed in terms of 1000 units, the "unit potentially replaced" metric actually refers to the installation of one million units.
Regional Technical Potential:
0.00 TWh per year
Regional Technical Potential of an Emerging Technology is calculated as follows:
Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Currently no data available.
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
Reference and Citations: