Editing Daylighting (architecture) (section)

==Solar lighting==
{{multiple image
 |direction = horizontal
 |align= right
 |width1= 230
 |width2= 132
 |image1=heliostat.jpg
 |image2=Residential Solar lighting in Santee.PNG
 |caption1=The reflecting mirror of a [[heliostat]]
 |caption2=A [[solar street light]]
}}

===Heliostats===
The use of [[heliostat]]s, mirrors which are moved automatically to reflect sunlight in a constant direction as the sun moves across the sky, is gaining popularity as an energy-efficient method of lighting. A heliostat can be used to shine sunlight directly through a window or skylight, or into any arrangement of optical elements, such as light tubes, that distribute the light where it is needed. The image shows a mirror that rotates on a computer-controlled, motor-driven [[altazimuth mount]].

===Solar street lights===
[[Solar street light]]s raised light sources which are powered by photovoltaic panels generally mounted on the lighting structure. The solar array of such off-grid [[PV system]] charges a [[rechargeable battery]], which powers a fluorescent or [[LED lamp]] during the night. Solar street lights are [[stand-alone power system]]s, and have the advantage of savings on trenching, landscaping, and maintenance costs, as well as on the electric bills, despite their higher initial cost compared to conventional street lighting. They are designed with sufficiently large batteries to ensure operation for at least a week and even in the worst situation, they are expected to dim only slightly.

===Hybrid solar lighting===
{{main|Hybrid solar lighting}}

[[Oak Ridge National Laboratory]] (ORNL) has developed a new alternative to skylights called hybrid solar lighting. This design uses a roof-mounted light collector, large-diameter [[Light tube#Optical fiber|optical fiber]], and modified efficient fluorescent lighting fixtures that have transparent rods connected to the optical fiber cables. Essentially no electricity is needed for daytime natural interior lighting.

Field tests conducted in 2006 and 2007 of the new HSL technology were promising, but the low-volume equipment production is still expensive. HSL should become more cost effective in the near future. A version that can withstand windstorms could begin to replace conventional commercial fluorescent lighting systems with improved implementations in 2008 and beyond. The U.S. 2007 Energy Bill provides funding for HSL R&D, and multiple large commercial buildings are ready to fund further HSL application development and deployment.

At night, ORNL HSL uses variable-intensity fluorescent lighting electronic control ballasts. As the sunlight gradually decreases at sunset, the fluorescent fixture is gradually turned up to give a near-constant level of interior lighting from daylight until after it becomes dark outside.

HSL may soon become an option for commercial interior lighting. It can transmit about half of the direct sunlight it receives.<ref name="hybrid lighting">{{cite web
 |author=Muhs, Jeff 
 |title=Design and Analysis of Hybrid Solar Lighting and Full-Spectrum Solar Energy Systems 
 |publisher=Oak Ridge National Laboratory 
 |url=http://www.ornl.gov/sci/solar/pdfs/Muhs_ASME_Paper.pdf 
 |access-date=2007-12-23 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20071128092954/http://www.ornl.gov/sci/solar/pdfs/Muhs_ASME_Paper.pdf 
 |archive-date=2007-11-28 
}}</ref>