Hybrid Solar Lighting
Hybrid solar lighting (HSL) collects the sunlight and distributes the light via optical fibers. The solar cells can be positioned for optimum sunlight gathering. The lamps are then positioned inside wherever they are needed. HSL can provide a significant energy savings that can be used to offset the costs of installation.
The basic components of an HSL system are a sunlight collector, optical fibers, and lamps.
The sunlight collector has two mirrors. The larger, primary one is a parabolic mirror design to catch the maximum amount of sunlight. The secondary mirror is segmented. It takes the sunlight caught by the primary mirror and focuses it into a plastic optical fibers.
The optical fibers carry the light to 2X4 foot fixtures with four fluorescent lamps. The fixtures are mostly standard, but modified to accommodate a sunlight diffusing rod to distribute the sunlight spatially.
Each HSL system can cover about 1000 sq. ft. of space. This can replace roughly 2 kW of electric lighting. The result is a significant savings in the electric bill. Typically, for commercial buildings, lighting is the number one consumer of electrical energy. And often less than 25% of that energy gets converted into useable light. The rest of the energy is dissipated as waste heat which in turn drives up the energy consumption for air conditioning.
In addition to the energy savings, HSL systems provide a more pleasant, natural light inside than can be achieved with electric lighting. And they do so in a far more versatile way than can be achieved by skylights. Skylights can lead to heat loss or gain, resulting in the need for more air conditioning or heating. They can place artificial constraints on the way a building is designed. They're susceptible to leakage, both water and air. They don't work with low ceilings. They can't be directed or turned off. And they pose a security risk.
HSL, by contrast, brings the natural glow of sunlight without creating any of those problems. HSL allows your building to be a sealed system, reducing the risk of leaks. You don't lose heat out the system during the winter or allow heat in during the summer. They work with low ceilings. They can be directed and turned off, just like artificial lights. And they don't leave a hole in the roof that burglars can climb through.
HSL is currently undergoing a nationwide field testing. This will provide more detailed performance data and allow the users to offer feedback to help refine the design. The result may soon be a more flexible, more affordable way of adapting solar energy to indoor lighting needs.