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Posted by Riddhi Singhania on behalf of the project team members: Gurjot Singh Bedi, Kushagra Maheshwari, Ranveer Kapoor, Riddhi Singhania, Vasudha Gupta – all from The Shishukunj International School, Indore, India
Project mentors: Mr. Ajaiy Pandey, Ms. Amita Agrawal, Mrs. Aradhika Dogre, Mr. Shailendra Kantak, Mrs. Suchita Das
Bulbs, tubelights, LEDs, torches- We pay their bills all right. But why, Why do we just ignore the Sun That rises daily for us… shining bright?
Yes. Bills. Not just electricity bills, but a remittance in the form of depleting fossil fuels, increasing carbon footprint, and most importantly, our health. Continuous hours of exposure of artificial lights is a major cause of insomnia, hypertension, anxiety, and depression.
One afternoon, we were told to finalize the project for the annual inter school Physics competition soon.
The topic was ‘sustainable environment’, but we find each and every aspect of this universe that we would like to improve or modify! We browsed several recent research works to gain some inspiration. We had almost decided upon a particular idea, when our teacher brought in the topic of fiber optics!
We, the students, were opposed to it… We had not heard about ‘pipes’ bringing sunlight inside, and it somehow seemed absurd!
We started the project, quite HALF-HEARTEDLY, but it didn’t take long for us to start LOVING it! We all are surrounded by artificial lights throughout the day. What is better than using fiber optics to bring the sun (or the sunlight) inside!?
We first took a quick survey of our school, counted the number of tubelights and LEDs in each classroom, corridor, or lab. We realized that our school paid an enormous amount of money just on electricity bills. We interviewed some staff members and EVERYONE said that they felt fresher and more productive in sunlight!
As soon as we finalized the project in the group, my friend quickly sketched out our first rough idea on paper, so as to get an official permission to proceed with it!
This is how the basic model is:
Sunlight can be captured and focused into ways: by concave mirrors or by convex lenses.
Our model consists of a concave reflector (placed on the roof) made up of metallic strips that converge the sunlight to a focal area, where we have the optical fibre bundles. The optical fibers carry the sunlight by total internal reflection to the other end, inside the room. Ceiling mounts spread the light.
Surely, this is a big task, and we took help from all possible resources to create the best. We visited local labs, met professors, studied about fiber optics, and explained our expectations. It was then a professor asked, “Are you sure you want to bring sunlight inside?” Our bellies lurched- oh, the sweet sunlight also has UVB rays!
Figure 3. Study of optical fibers at a local laboratory. Figure 4. Light coming through a single optical fiber
ARE we getting safe light? Then, to eliminate heat and UVB radiations, we decided to have a glass sheet on the concave reflector. It traps heat by greenhouse effect and absorbs most of the UVB rays.
This was the point when we were forced to explore the technicalities. We studied different topics ranging from numerical aperture, acceptance angle, single-mode, multi-mode fibers, step-index, graded-index optical fibers, and countless more! We studied their mathematical explanations and improved our model according to them:
We decided to use multi-mode step-index optical fibers to get the best TIR at a lower cost. We calculated that if red light (with the longest wavelength) can undergo TIR, all other visible rays will also get easily transferred. We thus noted that the critical angle must be such that it allows the transfer of red light.
We made a prototype and drafted a comprehensive report, making sure to verify our mathematical conclusions again and again. You are able to prove your idea only when you know how to present, how much your audience knows and what apprehensions they may have!
The technical gurus of the group made the presentation slides interactive, and I acted as the moderator of the work division. My friend and I took up the scripting role. We practised it scores of times during the day and add comparisons from our daily lives!
As our model was a prototype, we had many more potential improvements planned- Four photo-sensors fitted diametrically opposite to each other on the reflector can help us make it move like a sunflower, thus gaining the optimal amount of sunlight throughout the day. A slightly parabolic shape of the concave reflector can reduce spherical aberration. Our model can also have convex lenses to focus sunlight to the fibers bundle.
We researched as per India, where we have over 300 solar days a year. Once we minimize the electricity bills, and this system becomes affordable, it can be a great solution for basement lighting too!
After we received ‘Best Project Award’ at the inter school competition, we also took it to the regional science exhibition. It was during this fair that we met a Professor, representing another school, who gave us a friendly tip to improvise the model. We also qualified for the CBSE National Science Exhibition, New Delhi, India.
For places with restricting infrastructure, SUNLIGHTENMENT has the potential to become a great innovation for enhancing our working environment in a nature-friendly and cost-effective manner!