Smart Device to Harvest Daylight

‘Good’ machine to reap daylight. Credit score: NTU Singapore

Machine can be utilized to light up darkish, underground areas in daytime.

A crew of Nanyang Technological College, Singapore (NTU Singapore) researchers has designed a ‘good’ machine to reap daylight and relay it to underground areas, decreasing the necessity to attract on conventional power sources for lighting.

In Singapore, authorities are wanting on the feasibility of digging deeper underground to create new area for infrastructure, storage, and utilities. Demand for round the clock underground lighting is due to this fact anticipated to rise sooner or later.

To develop a daylight harvesting machine that may sustainably meet this want, the NTU crew drew inspiration from the magnifying glass, which can be utilized to focus daylight into one level.

Acrylic Ball Solar Concentrator

The acrylic ball (proper) of the machine acts because the photo voltaic concentrator, enabling daylight to type a pointy focus. The centered daylight is then collected into one finish of a fiber cable (left) and emitted through one other finish straight. Credit score: NTU Singapore

They used an off-the-shelf acrylic ball, a single plastic optical fiber — a kind of cable that carries a beam of sunshine from one finish to a different — and laptop chip-assisted motors.

The machine sits above floor and identical to the lens of a magnifying glass, the acrylic ball acts because the photo voltaic concentrator, enabling parallel rays of daylight to type a pointy focus at its reverse aspect. The centered daylight is then collected into one finish of a fiber cable and transported alongside it to the tip that’s deployed underground. Gentle is then emitted through the tip of the fiber cable straight.

On the identical time, small motors — assisted by laptop chips — mechanically regulate the place of the fiber’s gathering finish, to optimize the quantity of daylight that may be acquired and transported because the solar strikes throughout the sky.


Vivid concept: Daylight can now be introduced underground, because of NTU Singapore scientists who’ve constructed a ‘good’ machine to reap the daylight to mild up underground areas. Like a magnifying glass, the machine formed like a crystal ball focuses daylight into one level the place it’s collected on the finish of a fiber cable then transported to the opposite finish that’s deployed underground the place the sunshine is emitted. This reduces the necessity to faucet on conventional power sources for lighting. Credit score: NTU Singapore

Developed by Assistant Professor Yoo Seongwoo from the Faculty of Electrical and Electronics Engineering and Dr. Charu Goel, Principal Analysis Fellow at NTU’s The Photonics Institute, the innovation was reported within the peer-reviewed scientific journal Photo voltaic Vitality early this month.

The machine overcomes a number of limitations of present photo voltaic harvesting know-how. In typical photo voltaic concentrators, massive, curved mirrors are moved by heavy-duty motors to align the mirror dish to the solar. The elements in these methods are additionally uncovered to environmental components like moisture, growing upkeep necessities.

The NTU machine, nonetheless, is designed to make use of the spherical form of the acrylic ball, ridding the system of industrial quality motors to align with the solar, and making it compact.

The prototype designed by the researchers’ weighs 10 kg and has a complete top of fifty cm. To guard the acrylic ball from environmental situations (ultraviolet mild, mud and so forth.), the researchers additionally constructed a 3mm thick, clear dome-shaped cowl utilizing polycarbonate.

Machine compact sufficient to be mounted as a lamp submit

Asst Prof Yoo, lead creator of the examine mentioned, “Our innovation contains commercially obtainable off-the-shelf supplies, making it probably very simple to manufacture at scale. As a consequence of area constraints in densely populated cities, we have now deliberately designed the daylight harvesting system to be light-weight and compact. This might make it handy for our machine to be included into present infrastructure within the city atmosphere.”

Yoo Seongwoo Charu Goel

Researchers behind the ‘good’ machine to reap daylight are Assistant Professor Yoo Seongwoo (left) from the Faculty of Electrical and Electronics Engineering and Dr Charu Goel (proper), Principal Analysis Fellow at NTU’s The Photonics Institute. Credit score: NTU Singapore

The NTU crew believes the machine is ideally suited to be mounted as a traditional lamp submit above floor. This might allow the innovation for use in two methods: a tool to reap daylight within the day to mild up underground areas, and a streetlamp to light up above floor at evening utilizing electrical energy.

The analysis by the NTU scientists is an instance of NTU’s Good Campus imaginative and prescient that goals to develop technologically superior options for a sustainable future.

‘Good’ computerized positioning to reap most daylight

Because the solar strikes throughout the sky all through the day, so will the place of the centered daylight contained in the acrylic ball. To make sure that most daylight is being collected and transported down the fiber cable all through the day, the system makes use of a pc chip-based mechanism to trace the solar rays.

The International Positioning System (GPS) coordinates of the machine location are pre-loaded into the system, permitting it to find out the spot the place most daylight must be centered at any given time. Two small motors are then used to mechanically regulate the place of the fiber to catch and transport daylight from the centered spot at one-minute intervals.

To ensure the machine’s computerized positioning functionality, pairs of sensors that measure mild brightness are additionally positioned across the daylight gathering finish of the fiber cable. Every time the sensors detect inconsistencies within the mild measurements, the small motors mechanically activate to regulate the cable’s place till the values on the sensors are the identical. This means that the fiber is catching the utmost quantity of daylight doable.

Throughout rain or overcast skies when there’s insufficient daylight to be collected and transported underground, an LED bulb powered by electrical energy put in proper subsequent to the emitting finish of the fiber cable, will mechanically mild up. This ensures that the machine can illuminate underground areas all through the day with out interruption.

Performs higher than LED bulbs

In experiments in a pitch-black storeroom (to simulate an underground atmosphere), the NTU researchers discovered the machine’s luminous efficacy — the measure of how properly a lightweight supply produces seen mild utilizing 1 Watt {of electrical} power- to be at 230 lumens/Watt.

This far exceeds these recorded by commercially obtainable LED bulbs, which have a typical output of 90 lumens/Watt. The standard of the sunshine output of the NTU good machine can be comparable with present commercially obtainable daylight harvesting methods that are way more pricey.

Dr. Charu, who’s the primary creator of the examine, mentioned, “The luminous efficacy of our low-cost machine proves that it’s well-suited for low-level lighting purposes, like automobile parks, lifts, and underground walkways in dense cities. It is usually simply scalable. For the reason that light-capturing capability of the ball lens is proportional to its measurement, we are able to customise the machine to a desired output optical energy by changing it with a much bigger or smaller ball.

Michael Chia, Managing Director at Technolite, a Singapore-based design centered company specializing in lighting, and the trade collaborator of the analysis examine mentioned, “It’s our privilege and honor to take this innovation journey with NTU. Whereas we have now the business and software information, NTU in-depth know-how from a technical perspective has taken the execution of the mission to the following stage that’s past our expectations.”

Transferring ahead, the lighting firm is exploring methods to probably incorporate the good machine or its associated ideas into its industrial initiatives for improved effectivity and sustainability.

Reference: “Hybrid daylight harvesting system utilizing static ball lens concentrator and movable optical fiber” by Charu Goel and Seongwoo Yoo, 28 January 2021, Photo voltaic Vitality.
DOI: 10.1016/j.solener.2020.12.071

By Rana

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