Ubiquitous Communication by Light (UC-Light) is an emerging technology that uses visible light to perform wireless machine-to-machine communication. The mechanism at work with UC-Light is similar to the infrared technology used in TV remote controls, but UC-Light uses visible white light from modulated light emitting diodes (LEDs). Visible light communication (VLC) is potentially cheaper than conventional wireless communications because VLC can use pre-existing LED luminaires for communication purposes.
With support from a CITRIS seed grant, researchers at CLTC and UC Berkeley are working together to develop advanced lighting control algorithms that make use of multiple data streams, both local and remote, to improve lighting and energy management in buildings. Applications include electrical lighting systems in commercial spaces with windows and/or skylights.
CLTC is partnering with the UC Davis Energy Efficiency Center (EEC) to address untapped efficiency opportunities in the Multi-Tenant Light Commercial (MTLC) building sector. The project is focused on identifying and overcoming the biggest barriers to energy-efficiency retrofits in the MTLC market. More than half of the energy-saving contributions of the team's proposed solutions will come from lighting-related retrofits, as the group hopes to reduce interior lighting energy consumption by 20% and exterior lighting energy consumption by as much as 50%.
CLTC is collaborating with the California Energy Commission and the California Institute for Energy and Environment (CIEE) to develop adaptive envelope technologies for retail and agricultural buildings. The objective is to develop systems that optimize both lighting and thermal efficiency in these facilities, using advanced fenestration materials, daylighting technologies and lighting controls.
CLTC research, demonstrations and case studies have shown adaptive corridor and stairwell lighting systems are a cost-effective strategy for achieving lighting energy savings of 40–50%. This is because many stairwells and corridors are illuminated continuously, despite low occupancy rates, and are usually equipped with standard, non-dimmable ballasts and operated with wall switches or from a panel box.
Core sunlighting systems deliver sunlight deep into multi-story building cores, where daylight is not available through skylights or windows. An effective core sunlighting system offers physiological and psychological benefits to occupants while dramatically improving the quality and color rendering of lighting, reducing lighting electricity use up to 75%, and reducing electricity loads during peak demand periods.
CLTC is evaluating dynamic skylight systems that automatically adjust light transmission to minimize glare and manage solar heat gain, significantly improving both lighting quality and energy savings. Engineers are using one of the Center's integrating spheres to measure the transmittance of different sample units.
Applications include residential and commercial spaces that receive sufficient sunlight to require some form of shading for occupant comfort or to prevent solar heat gain.
Last June UC Davis replaced 101 static HPS and MH wall packs with adaptive LED wall packs by Philips, equipping them with outdoor motion sensors by WattStopper and networked controls from Lumewave. Along with streetlights and post-top luminaires, the wall packs were incorporated into the Adaptive Campus Control System at UC Davis, via an RF network that provides campus-wide lighting control.
Wall packs offer an effective means of illuminating building perimeters, bolstering security and aiding wayfinding, but many are limited in terms of their efficiency, with minimal or nonexistent cutoff. Moreover, because wall packs typically operate in areas with low occupancy rates, they often waste energy fully illuminating vacant spaces for hours at a time every night.