About Daylight Harvesting Systems
On March 2022, Ministry of Science & Technology has decided to promote a unique, possibly India’s first, Start-up in latest Daylight Harvesting Technology.
TDB-DST will promote the Start-up in Daylight Harvesting Technology to reduce carbon footprint and improve the building energy efficiency.
“Skyshade Daylights Private Limited” Hyderabad signed a MoU with Technology Development Board, a statutory body of Department of Science & Technology.
TDB will give Rs 5 Crore of the 10 Crore project to Skyshade company for developing new technologies for basement illumination on 24×7 basis.
What is a daylight harvesting system?
A daylight harvesting system is a way to use sunlight light to reduce the amount of electric lighting needed in a building.
The system uses a light sensor to measure the amount of daylight available and then adjusts the electric lighting accordingly.
Daylight harvesting systems can save a significant amount of energy in buildings. In some cases, daylight harvesting can reduce energy consumption by up to 50%.
Daylight Harvesting Working Principle
The entrance point usually comprises a dome (Hemi Speperical), which has the function of collecting and reflecting as much sunlight as possible into the tube.
It is fitted Optical collectors, Reflectors or even Optical Diffuser that assist in collecting additional directional light down the tube.
Tube / Light pipes may be either hollow structures that contain the light with a reflective lining or transparent solids that contain the light by total internal reflection.
This tube is starting from an entrance point located on its roof or one of its outer walls. This light tube is used only carrying light not for image.
A set-up in which a laser cut acrylic panel is arranged to redirect sunlight into a horizontally or vertically orientated mirrored pipe.
This system combined with a light spreading system with a triangular arrangement of laser cut panels that spread the light into the room.
At the end point (the point of use), a diffuser spreads the light into the room.
Types of Daylight Harvesting as Per Installation
i) Spherical Sytem
ii) Rectangular or Elliptical
Types of Daylight Harvesting as Per Working
There are two main types of daylight harvesting systems:
Open-loop systems: These systems do not take into account the amount of electric lighting that is already on. The light sensor simply measures the amount of daylight available, and then adjusts the electric lighting accordingly.
Closed-loop systems: These systems take into account the amount of electric lighting that is already on. The light sensor measures the amount of daylight available, and then adjusts the electric lighting so that the total amount of light in the space remains constant.
Basic sketch of Daylight Harvesting
https://rahulrainbow.com/, Daylight Harvesting System
There are many benefits of daylight harvesting, including:
Energy savings: Daylight harvesting can save a significant amount of energy in buildings. In some cases, daylight harvesting can reduce energy consumption by up to 50%.
Improved occupant comfort: Daylight has been shown to improve occupant comfort and productivity. Studies have shown that people who work in well-lit spaces are more productive and less likely to experience eyestrain, headaches, and fatigue.
Reduced glare: Daylight harvesting can help to reduce glare in buildings. Glare can be a problem for people who are working on computers or other visual tasks. Daylight harvesting can help to reduce glare by controlling the amount of light that enters a space.
Improved circadian rhythm: Daylight has been shown to help to improve circadian rhythm. Circadian rhythm is the body’s natural sleep-wake cycle. Daylight can help to regulate circadian rhythm by providing the body with a natural light source.
Increased sustainability: Daylight harvesting is a sustainable way to light buildings. It reduces the need for artificial lighting, which can help to reduce greenhouse gas emissions.
Reduced carbon footprint: Daylight harvesting can significantly reduce your carbon footprint. In India especially where coal is still the primary source for electricity, Energy Savings would mean lesser air pollution due to the burning of coal and conservation of a non-renewable natural resource. Energy saving practices can also make your building eligible for green building certifications like LEED.
LEED: Leadership in Energy and Environmental Design (LEED) is the most widely known green building certification program. It was developed by the U.S. Green Building Council (USGBC) and is based on a points system that rewards buildings for their performance in areas such as energy efficiency, water conservation, materials selection, and indoor environmental quality.
Total internal reflection (TIR) : It is the phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second (“external”) medium, but completely reflected back into the first (“internal”) medium.
It occurs when the second medium has a higher wave speed (i.e., lower refractive index) than the first, and the waves are incident at a sufficiently oblique angle on the interface.
The critical angle is the angle of incidence at which total internal reflection occurs. It is defined as the angle of incidence for which the angle of refraction is 90 degrees.
The formula for the critical angle is:
θc = sin −1 ( n 2 n 1 )
θc is the critical angle
n1 is the refractive index of the first medium
n2 is the refractive index of the second medium
For example, the critical angle for water-air is 48.6 degrees. This means that if a ray of light is incident on the water-air interface at an angle of 48.6 degrees or greater, it will be totally reflected back into the water.
Total internal reflection has a number of applications, including:
Fiber optics: Fiber optics use total internal reflection to transmit light signals over long distances.
Prisms: Prisms use total internal reflection to bend light rays.
Periscopes: Periscopes use total internal reflection to see around corners.
Lasers: Lasers use total internal reflection to create a beam of coherent light.
Total internal reflection is a fascinating phenomenon that has a number of practical applications. It is a good example of how the properties of light can be used to create useful devices.
Cost of Day Harvesting System
Normally it cost varies from Rs. 8k to 50 k. Generally it acquires 1.5 sqm space, vertical height as per requirement. Around 1 year,it is able to return invested cost as per standard conditions.
Name of Reputed Manufacturers
Uday Iksa Private Limited , Dharwad,
Supreme Fibre Glass Private Limited, Vasai East, Mumbai, Maharashtra
Dura Plast,Neharpar, Faridabad
Green Energy Solutions, New Santoshpur, Kolkata
Day Light Power Solutions, Sarjapura, Bengaluru
Skyshade Daylights Private Limited,Hyderabad
National Solar,Durgapur, Kolkata
Tanstate Global,Baner, Pune
Anybody who wants to add more information regarding daylight harvesting , please share their knowledge with us which is very helpful for others. If u are user or manufacturer of the daylight harvesting system & want to share more information, please mail on :firstname.lastname@example.org.