Daylighting systems

Hybrid system: daylighting and concentrating photovoltaic (CPV)

A simple model for a hybrid lighting-CPV module is demonstrated. It consists of a bifocal Fresnel lens parquet where part of the overall collector area is used for directing sunlight towards the optical guide, while the remaining area focuses the incoming light onto a solar cell for electrical energy conversion, as in a conventional CPV system. The corners of the CPV Fresnel lens are the least efficient areas of the lens because they need to redirect incoming light over larger angles and have a lower acceptance angle. These areas can be better made the most if they are devoted to the illumination system by shaping a new lens that focuses the sunlight on the fiber and constitutes the primary optical stage of the lighting system. Read more

Hybrid daylighting system: optical fiber-based daylighting and photovoltaic

Hybrid concentrated photovoltaics (CPV) and daylighting

sunlight is used to generate electricity through solar cells and provide sunlight inside the building to reduce electric lighting energy consumption and improve indoor environment.

Hybrid daylighting system: lighting and photovoltaic

Hybrid daylighting system: lighting and photovoltaic

This idea presents the use of the optical fiber and a solar concentrator for a daylighting addressing system in buildings. The light is collected through a sun-tracking parabolic concentrator system and transmitted through optical fibers. The PV systems is composed by a primary parabolic collector (PPC) which concentrates solar light to a secondary flat optical reflector (SOE) made by a series of cold mirrors. The near infra-red part of the solar spectrum is transmitted over to feed photovoltaic cells, and remaining is transmitted into optical fiber for lighting. Read more

Hybrid daylighting system: lighting and photovoltaic

Sunlight transmission via optical fibers with high precision tracking system

A high precision tracking system is used to focus the light into optical fibers through a lenses. Read more

Fiber-optic daylighting system using high precision tracking

Parans optical fiber-based daylighting system

Small lenses are used to concentrate sunlight into optical fibers, and light is distributed at the interior through the fiber bundle. Read more

Parans daylighting system using optical fiber

Core solar lighting system

Lighting is directed through an array of small flat mirrors and then light is concentrated through two mirrors. Light is inserted into the light guide through light pipes to distribute the light in the interior. Read more

Core daylighting system

Two stage concentration using flat reflectors

Flat reflectors help to achieve uniform illumination at second stage of concentration.Read more

Two stage concentration using flat reflectors

Sunlight transmission via optical fibers

A high precision tracking system is used to focus the light into optical fibers through a lens. Read more

Sunlight transmission via optical fibers

Microstructured daylighting system

The basic concept of daylighting is to reduce the electricity consumption while maintaining a high-quality illumination. The mechanism of microstructured daylighting system is that the sunlight is redirected through microstructured light-directing element, which is made of plastic, toward the ceiling of the room. The complexity and costs has been reduced in the presented model. The quality of the light distribution and the guidance deep into the room has further been enhanced by using freeform geometries. Read more

Microstructured daylighting system

Sunportal daylighting system

The natural daylighting system that can transport sunlight within a building. Sunportal has begun offering a daylighting system that collects natural light with a parabolic dish concentrator and delivers it through pipes to rooms in a building. Read more

Sunportal daylighting system

Central sunlighting system (CSS)

Energy performance of the CSS has been evaluated, and it is found that it may save a significant amount of energy. Energy savings from the combination of daylighting from windows and the CSS for typical, four-cubicle, open plan offices range from 44% to 57% for lighting, 8% for cooling, and from 14% to 23% for the total (lighting, cooling, and heating) energy. Read more

Sunportal daylighting system

Sunflower daylighting System

Sunlight is collect through a lens made of plastic (PMMA) and delivered through the optical fibers for lighting. Read more

Sunflower daylighting system

Light pipe vs. fiber optic dish concentrator

It is demonstrated that more daylight can be harvested by the solar tracking dish concentrator system for solar altitudes of less than 50 degrees. Its uniformity ratio remains between 0.55 and 0.72, varying quite less than that of the light pipe, ranging from 0.46 to 0.88. Read more

Light Pipe vs. Fiber Optic Dish Concentrator

Daylighting system with truncated compound parabolic concentrator (CPC) array collectors

Many small truncated CPC are used to collect sunlight, and then transmitted into lightguide Read more

Daylighting system with truncated compound parabolic concentrator (CPC) array collectors

Optical fiber based daylighting system using parabolic dish

Optical fiber is an efficient source for light transmission at long distances. For solar applications (daylighting, solar thermal, and photovoltaic), optical fiber has been declared an important element to transmit light with very small losses. To insert maximum concentrated light into optical fibers, parabolic dish concentrator is the best choice, which has very high efficiency to collect sunlight. It has been demonstrated and verified that a combination of concave and convex parabolic reflectors gives collimated light, which illuminates the bundle of optical fibers uniformly. Therefore, uniform sunlight is achieved at deep inside the building. Read more

Optical Fiber based daylighting system using parabolic dish

Optical fiber based daylighting system using Fresnel lens

Fresnel lens has been declared an important element in the solar energy applications (daylighting and solar thermal) to concentrate sunlight. It is preferred to make the system cost-effective. A combination of Fresnel lens and plano-concave lens is the best choice to get uniform and collimated illumination, which is desired in many applications (e.g., transmission of sunlight through optical fibers). Read more

Optical Fiber based daylighting system using Fresnel lens

Solar lighting optical switching system

When the system is turned off, the sunlight is focused by a concentrator, to be absorbed by solar photovoltaic devices that provide the electricity to power the LEDs. When the system is turned on, the sunlight collected by the concentrator is split into visible and non-visible rays. The visible rays are mixed with LED light. The non-visible rays are absorbed by the solar photovoltaic devices. Read more

Solar lighting optical switching system

Himawari solar lighting system

Sun tracking solar lighting system using optical fibers was invented by a Japanese inventor (V. Elaine Gilmore). It was published with the title “Sunflower over Tokyo” in popular science, 1988.

Himawari Solar lighting system

Overall concept of solar lighting systems

The concept of daylighting is shown in the following Figure.

Overall concept of solar lighting systems