What is daylight harvesting?
Daylight harvesting is an advanced lighting control technology enabling business owners to save the energy cost of their facilities. According to the Green Education Foundation, “electrical power consumption for lighting” is one of the largest sources of building energy consumption. The electric lighting cost usually takes up around 17% of energy costs for office buildings. For schools, the cost can be over 30%. Daylight harvesting allows buildings to collect and utilize natural light inside the building to reduce the cost of using artificial lighting, according to Green Education Foundation.
According to Lighting Controls Association, daylight harvesting relies on various sensors, which measure the amount of natural light in each part of the building and adjust the electric lights accordingly. Utilizing natural light helps decrease the need for artificial lighting. Therefore, the energy cost is reduced.
What are suntrackers?
In order to harness natural light, installation of suntrackers is required. Suntrackers combine solar power and sun-tracking GPS technology to “actively reflect natural light from a set of mirrors into a building,” according to Ciralight, the suntracker brand that EnergyLink works with. The technology which allows suntrackers to work efficiently includes: GPS controllers, diffusion and thermal barrier, mirror array and a plastic dome, according to Ciralight.
However, in order to be effective, suntrackers require the building to have good southern exposure and available roof space.
How daylight harvesting saves you money?
Based on Ciralight’s statistics, daylight harvesting technology enables buildings to turn off the lights up to 10.5 hours per day. According to a controlled experiment on energy savings from daylighting conducted by the ACEEE, daylighting allows the facilities to save 32% of lighting costs. A case study on Northern Arizona University written by the U.S. Department of Energy shows a 30% energy savings with lighting control systems. By using solar-powered suntrackers, businesses can expect a return on investment in 3 to 5 years after the installation.
Other benefits of suntrackers
It is also worth noting that natural light helps “restore the mind from the mental fatigue of work or studies” and forms a more attractive, pleasant, and healthy work environment in the buildings, according to a research conducted by the University of Washington. Thus, daylight harvesting can not only save energy cost, but also improve working environment.
EnergyLink has installed suntrackers in multiple projects in the past and is very experienced with daylight harvesting. If you are interested in daylight harvesting, click here to have our certified energy auditors analyze your facility to determine whether your building is a good fit.