Sekhar Nori has come up with a product he calls the Day360 Integrated Daylight System (IDS). This is a lighting system that harvests day light to provide free lighting during the day and electrical lighting at night. It is controlled automatically by the system but has manual override option for those special occasions.

Sekhar Nori says, “During my former experience with solar energy field, where I worked with solar conversion, I found that the conversion ratio of solar energy is comparatively depressed. This caused the system costs to be relatively high. This is when we recognised that it is time to convey the visual solar energy as light itself.”

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In this system you do not convert day light into any other form of energy like heat or electricity. This helps increase the product’s life, the product becomes more affordable which, in turn, increases the return on investment.

What it is
It is a concept where both natural day light and electrical lighting are integrated into a single and simple platform. Depending on the availability of day light, the electrical lighting system switches on or off to complement light in the area.

Although the Day360 IDS was deduced from the idea of Lightpipe (a solar daylight system), it is a completely new solution with daylight system being just a part of it. The IDS makes use of electrical lighting, day lighting, light sensors and a lighting controller for an all-in-one system that even has smart meter functionality.

Sekhar says, “We did a lot of R&D for IDS for about one-and-a-half year. This year we finally finished its design and fabrication. IDS is a completely new way of providing an automatic lighting solution for commercial buildings.”

How it works
The daylight system part of IDS has a light collector, a reflective system and light diffusers. The light collector collects sun light and the reflective system transports this light just like an optical fibre. The light diffusers take the light out of the tube and diffuse it into the building.

Lighting controllers. The lighting controllers take care of the entire working of the IDS and also help in switching between day light and electrical lighting. The lighting controller has three parts—daylight sensing, control system and a central control panel.

Sekhar says, “The light sensing element used by IDS is a special light sensor built by us. This is an open loop light sensor. Normally the light sensor used in building works in a closed loop. The light sensor that we build gives a continuous feedback to the lighting controller. In an open loop sensor the light is measured from the ambient sky and never measured in the task plane. Whereas in closed loop sensor light is continuously measured at the task pane (a task pane could be either floor level or any other plane) and is given as a feedback to the controller.”

The light sensor continuously measures the ambient sun light. If the ambient sun light is less than the desired light intensity required in the room, the lighting controller turns on the electrical lighting. The electrical lighting is divided into three groups, each representing a step for switching on or off. Depending upon the light intensity, the controller turns on required number of steps in electric lighting. Nori adds, “The lighting controls and the central control panels are also built in-house. All lighting systems can be controlled through central control panels.”

Monitor and control energy. The control system monitors the energy consumed and the savings on the lighting system like a smart meter. It also allows the manual override of the system, monitors failures and the data inputs.

Sekhar explains that the main technology behind IDS is the response of electrical lighting to the available day light. He adds, “In this system we have built a couple of other features too, like the smart metering of energy consumption. The energy consumption of the electric lighting system is continuously measured, metered and displayed in a control panel. So the utility managers or the facility managers can actually monitor the power consumption of the lighting systems and track the energy savings they are able to make, and then they can also convert it to carbon credits.”

To convince is a challenge
Sekhar says, “We are not used to the concept of day lighting but are used to electrical lighting. The buildings too are built in such a way that there is no methodology to use day light. So people stay connected to the electrical lighting without considering the use of day lighting. Our challenge here is to convince people that we have a methodology to use this day lighting.

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