Empirical techniques for characterizing electrical energy use now play a key role in reducing electricity consumption, particularly miscellaneous electrical loads, in buildings. Identifying device operating modes (mode extraction) creates a better understanding of both device and system behaviors. Using clustering to extract operating modes from electrical load data can provide valuable insights into device behavior and identify opportunities for energy savings. We present a fast and effective heuristic clustering method to identify and extract operating modes in electrical load data.
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The General Service Administration's (GSA) Green Proving Ground (GPG) program worked with a team from the National Renewable Energy Laboratory (NREL) to identify buildings with office setups and equipment distributions typical of the wider GSA building stock. Eight buildings from GSA’s Mid-Atlantic Region, where plug loads average 21%, were selected. In each building, approximately 12 standard power strips with no control capability (the incumbent technology) were replaced with APSs, which monitored and provided power to an array of devices. More than 295 devices were monitored during the study, which consisted of three separate test periods, each four weeks in length. All buildings selected had workstation power management in place.
Energy savings can be achieved in corridors and other secondary spaces with an occupancy-based adaptive lighting system. Such a system is generally composed of occupancy sensors, dimmable ballasts and a communication platform. The system automatically lowers light levels to the minimum footcandles required by safety codes during vacancy and raises light output to the recommended level for occupant comfort during occupied periods. The adaptive lighting system installed at the Latham Square office building is based on Lutron’s Energi TriPak solution, a stand-alone platform for adaptive lighting that employs cost-effective wireless control devices and programmable dimming ballasts.
The California Lighting Technology Center partnered with Finelite, Inc. and Adura Technologies to develop and demonstrate a unique, wireless task/ambient office lighting solution ideally suited for the retrofit market. The system consists of two key elements: a task/ambient lighting system and advanced, wireless lighting controls. The combination substantially reduce energy use and improves lighting quality, and provides personal lighting control for individual work spaces, and does not require additional wiring or rewiring of existing luminaries or lighting circuits. The system has three specific components: adaptive ambient lighting, light-emitting diode task lighting, and wireless controls.
To maximize the respective benefits of open- and closed-loop systems, and minimize their limitations, the California Lighting Technology Center (CLTC) developed a dual-loop photosensor control system for skylight applications. The system features a control algorithm that monitors the open- and closed-loop photosensors and controls the electric light to provide the designed light level. It also automatically recalibrates nightly to adjust to long-term changes to the interior space. Results show the dual-loop technology delivers more consistent lighting and greater energy savings.
The California Energy Commission’s Public Interest Energy Research (PIER) program sponsored development of bi-level parking garage luminaires for the University of California, Davis that integrate intelligent controls with bi-level electronic drivers or ballasts to control light output based on garage occupancy. Luminaires operate at a reduced level during vacancy and switch to full light output upon occupancy. Many of the products may be combined with traditional photocontrols to maximize energy savings.
In 2012, University of California Davis upgraded its exterior lighting as part of the university’s Smart Lighting Initiative. Wall packs on campus, like other exterior lighting fixtures, were retrofitted with dimmable LED sources, motion sensors, and wireless controls. This allowed the units to be incorporated into an adaptive campus-wide lighting control system. The system offers an intelligent, networked approach to lighting and energy management with improved lighting quality and optimal energy efficiency.
In the summer of 2010 the California Lighting Technology Center (CLTC) and Philips Hadco produced a bi-level solution that combined a dimmable LED source and a mounting collar equipped with occupancy sensors. The collar provides 360-degree occupancy sensor coverage. This demonstration involved whole-head replacement of the existing luminaires, but results could also be achieved with a retrofit kit. The new luminaires feature good color quality, improved efficiency and a longer lifespan. Adaptive controls enable the bi-level luminaires to reduce power to 50% during vacant periods and increase to 100% light output when occupants approach. Switching between the two light levels maintains adequate light for security and wayfinding while maximizing energy savings.
The PIER Demonstration program partnered with the University of California, Davis to demonstrate new construction and retrofit design strategies that provide dual light levels based on occupancy sensing that is appropriate for the interior corridor application. This demonstration project consists of a one-to-one retrofit of existing fluorescent luminaires with either new fixtures or new components for three corridor areas in Bainer Hall. This project is intended to demonstrate the energy savings that can be achieved by using occupancy-based controls for interior corridor applications.
This guide was sponsored by the California Energy Commission and developed by the California Lighting Technology Center at UC Davis. It is intended to be used as a supplement for the 2008 Residential Compliance Manual. It is a resource to help contractors, designers, and builders understand the 2008 Title 24 Building Energy Efficiency Standards and how to integrate these changes into new home plans. This guide consists of two key sections: the Technology Overview and the Lighting Design Guide.