Melissa Voss Lapsa

Hybrid Solar Lighting Provides Energy Savings and Reduces Waste Heat

ABSTRACT Artificial lighting is the largest component of electricity use in commercial U.S. buildings. Hybrid solar lighting (HSL) provides an exciting new means of reducing energy consumption while also delivering significant ancillary benefits associated with natural lighting in buildings. As more than half of all federal facilities are in the Sunbelt region (defined as having an average direct solar radiation of greater than 4 kWh/m2/day) and as more than half of all square footage available in federal buildings is also in the Sunbelt, HSL is an excellent technology fit for federal facilities. The HSL technology uses a rooftop, 4-ft-wide dish and secondary mirror that track the sun throughout the day (Figure 1). The collector system focuses the sunlight onto 127 optical fibers. The fibers serve as flexible light pipes and are connected to hybrid light fixtures that have special diffusion rods that spread out the light in all directions. One collector powers about eight hybrid light fixtures—which can i...

COMMUNICATION ACROSS THE BLACK SEA VIA INTERNET TECHNOLOGY

ABSTRACT The U.S. Department of Energys (DOEs) Office of International Affairs has been joined by an interagency task force to undertake a program in the Black Sea region called the “Black Sea En...

Spectral Transmission of a Solar Collector and Fiber Optic Distribution Hybrid Lighting System

Increased use of solar energy will reduce requirements for non-renewable energy sources such as fossil fuels and reduce associated greenhouse gas emissions. The benefits of replacing fossil-based energy with solar energy are often dependent on the application and operational or duty cycle for power demand. One particularly efficient use of solar energy is hybrid lighting. In hybrid lighting, solar light is concentrated into optical fibers and then coupled with supplemental electrical lighting to maintain a constant level of illumination. The system is able to offer reliable lighting with less energy consumption from the electrical grid (which is often driven by non-renewable sources). This technique offers energy efficiency benefits since the solar light is used directly and suffers no conversion losses. Furthermore, the solar spectrum provides an illumination that lighting engineers value for it’s quality; office inhabitants appreciate for its comfort; and retailers believe leads to increased sales. When available solar light is low, the hybrid system allows traditional light sources to reliably meet lighting demands. The success of the solar hybrid lighting system is dependent on the collection and transmission efficiency of the system. In this study, the spectral transmission of a hybrid lighting system is characterized. The system is composed of a 200-sun concentration reflective solar collector and a plastic fiber optic distribution network. The ultraviolet (UV), visible, and near-infrared (NIR) spectral transmission was characterized over a spectral range of 200 nm to 2400 nm. The UV and NIR performance of the system is critical since optical fiber damage can be caused by both UV and NIR light; thus, optimal system design maximizes the collection and transmission of visible light while minimizing the transmission of the UV and NIR light. Spectral transmission data for all components in the hybrid system are presented, and performance properties relative to solar applications are discussed.

Solar Energy, Collected, Concentrated, Transported, and Distributed as Light With No Energy Conversion Via a Hybrid Solar Lighting System

Hybrid solar lighting (HSL) is a technology in which sunlight is collected and distributed via optical fibers into the interior of buildings. Analogous to hybrid electric vehicles that use both batteries and internal combustion engines to power cars, hybrid lighting employs roof-mounted collectors to concentrate sunlight into flexible optical fibers and carry it inside buildings to “hybrid” light fixtures that also contain electric lamps. As the two light sources work in tandem, control systems keep lighting levels constant by dimming the electric lights when sunlight is bright, and turning them up as the sky darkens with weather conditions or nightfall. Data indicate that on a bright, sunny day the power consumption for lighting can be reduced by 50% or more. Today, lighting in U.S. residential and commercial buildings consumes close to 5 quadrillion BTUs of primary energy and one-fifth of all electricity. In commercial buildings, one-quarter of all energy demand is for lighting. With a forecasted doubling of commercial floor space by the year 2020 comes an urgent and growing need to find more efficient ways of lighting our nation’s buildings. Typically, less than 25 percent of the electrical energy consumed for lighting actually produces light; the rest generates heat, which increases the need for air-conditioning. Unlike conventional electric lamps, the sunlight from HSL systems produces virtually no waste heat. A nationwide field trial program is under way to provide system performance data and user-feedback essential for the successful commercialization of HSL. Field trial installations include San Diego State University, San Diego, CA; Pacific Northwest National Laboratory, Richland, WA; Sacramento Municipal Utility District, Sacramento, CA; Wal-Mart, McKinney, TX; Aveda Corp., Minneapolis, MN; Staples, Long Island, NY; Braden’s Furniture, Knoxville, TN; Multipurpose Research Facility, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN; University of Nevada-Las Vegas, Las Vegas, NV; Hybrid Lighting Laboratory, ORNL, Oak Ridge, TN. This paper describes the field trial program and summarizes the results to date from the field trial installations.

Site Sustainability Plan with FY2015 Performance Data

Oak Ridge National Laboratory (ORNL) is both the largest science and energy laboratory in the US Department of Energy (DOE) complex and one of the oldest national laboratories still operating at its original site. ORNL implemented an aggressive modernization program in 2000, providing modern, energy-efficient facilities that help to support the growth of important national scientific missions while faced with the unique and challenging opportunity to integrate sustainability into legacy assets. ORNL is committed to leveraging the outcomes of DOE-sponsored research programs to maximize the efficient use of energy and natural resources across a diverse campus. ORNL leadership in conjunction with the Sustainable Campus Initiative (SCI) maintains a commitment to the integration of technical innovations into new and existing facilities, systems, and processes with a comprehensive approach to achieving DOE directives and the new Executive Order 13693. Energy efficiency, greenhouse gas reductions, climate change resiliency, and other pursuits toward integrated sustainability factor in all we do. ORNL continues to pursue and deploy innovative solutions and initiatives to advance regional, national, and worldwide sustainability and continues to transform its culture and engage employees in supporting sustainability at work, at home, and in the community.

Current Renewable Energy Technologies and Future Projections

The generally acknowledged sources of renewable energy are wind, geothermal, biomass, solar, hydropower, and hydrogen. Renewable energy technologies are crucial to the production and utilization of energy from these regenerative and virtually inexhaustible sources. Furthermore, renewable energy technologies provide benefits beyond the establishment of sustainable energy resources. For example, these technologies produce negligible amounts of greenhouse gases and other pollutants in providing energy, and they exploit domestically available energy sources, thereby reducing our dependence on both the importation of fossil fuels and the use of nuclear fuels. The market price of renewable energy technologies does not reflect the economic value of these added benefits.