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An innovative product developed by a Mumbai entrepreneur duo not only converts sunlight into electricity but also harvests rainwater and provides shade

The upturned umbrellas installed at a car park in Pune (Photo by ThinkPhi)

Sometimes the simplest ideas are the most effective. This seems true of the inverted or upturned umbrella that a Mumbai clean-tech start-up has devised to both store potable water and generate solar energy.

Also known as ulta chaata colloquially, the USP of the device invented by ThinkPhi in 2015 is that it has multiple uses and isn’t just a standalone product. Its base model, 1080W, is touted as “the world’s most advanced shading structure…the first-of-its kind shade with integrated rainwater harvesting and solar powered lighting”.

The founders, Samit Choksi and his wife, Priya Vakil, who had worked abroad for several years, found it strange the two basic requirements – solar energy and drinking water ­– were easy to provide technologically, but no one had thought of combining both in a single device, which is particularly suitable for any tropical developing country.

This model comes in two sizes – 4m by 4m or 5m by 5m – and stands 2.6 m or 8.5 ft high. It weighs 100kg and 120 kg and can withstand winds up to 140 kmph. The structure has a warranty of 15 years, while the electrical components have warranty for five years.

“It is unique in the world. We have not come across anyone who competes with us,” Rajesh Das of ThinkPhi told “The canopy is an easy, three-in-one concept that delivers potable water, solar energy and shade. We have patented the design and filed for patents in India too.”

The structure is made of stainless steel and the canopy is of a synthetic coated membrane. It weighs, depending on the model, a minimum of 100 kg.

There are three generic models at present, with the third, 1080XL, under development. They are capable of modular development with a membrane that joins one unit to another, thereby becoming flexible enough to provide cover for customised needs.

“We have hi-fi clients like the Nagpur Metro, where we will be providing walkways from the station for passengers to approach the auto or taxi stands. These will also protect them from the rain and sun,” said Das. “Units can be tailor-made even for the platforms.”

Green and renewable

“It’s a question of compliance: it is green and renewable,” Das said, referring to the widespread search of late to find ways and means of cutting one’s carbon footprint.

ThinkPhi has sold some 400 units so far. Unlike many other renewable energy devices, particularly with regard with wind, the umbrella has little installation costs and is basically a plug-and-play device.

For large infrastructure companies, the top of the line 1080XL can go up to 20m x 20m. The National Highway Authority of India (NHAI) is considering installing these at toll plazas; the existing covering structures are merely “idle sheets”. The cost can go up to INR 8 million, depending on the size and energy output.

The umbrellas are capable of providing lighting in the night (Photo by ThinkPhi)

Similarly, the Airports Authority of India, as well as the private airport operators GMR and GVK, and the new Navi Mumbai airport are potential customers.

The XL (extra-large) version for infrastructure can vary from location to location, depending on different environments. ThinkPhi is now in some 60 locations around the country.

The umbrellas can process 150,000 litres of water during the monsoon, which is purified to make it potable. In the dry season, which is eight to nine months in the year, the solar cells in the base model 1080W have a capacity of 1.5 kW on a single charge, rather like a standalone rooftop solar unit, not connected to the grid. The XL is a superstructure which has the capacity of 40 kW on a single charge and can filter over 1 million litres of rainwater. The power is stored in a battery within the device which can power it as well as service nearby facilities.

The solar power lights up the umbrella at night but can also charge mobiles and even electronic vehicles. In large installations, it has the potential of feeding excess electricity to the grid which will defray the cost of the device to an extent.

Smart umbrella

The “brain” of the smart umbrella used to be a central operating unit called a Phi-box. There is now in prototype a remote monitoring box for the 1080E and 1080E+ where you can track water, energy, and a list of other environment pollutants in the microclimate.

The water is filtered in the mast at two levels. The first employs carbon filtration, where active carbon removes impurities. This lowers turbidity and improves clearness to World Health Organisation potable standards.

Naren Kolary of Think-phi describes the product as its “bread and butter device” since it is an alternative method of providing shade, so essential at a number of public and private spaces which are in the open, like toll plazas.

“Solar has the limitation of space,” he told, referring to the large area that a large-capacity solar power plant needs to erect its panels. “Space is at a premium so that solar power only makes sense in the right location.” The umbrella, on the other hand, is versatile since it can be erected at several locations where it performs multiple functions.

The XL model has a lithium battery to store power and provides self-lighting for the device. This can easily charge mobile phones and laptops. To charge electric vehicles, considering that the government is banning petroleum-based fuels for cars from 2030, however, requires a bigger installation like at car parks.


“One can find the right application in urban and semi-urban areas,” Kolary said. What is more, the device can be retrofitted into an existing structure or space. “In India, green technology for industrial use is dull and has a zero-design aspect to it,” Samit Choksi told Tech In Asia, a tech start-up website. “Companies spend money on green technology, but it is not visible. Solar, for instance, is a norm now, but you don’t ‘see’ it. Customers and employees will not climb onto the roof to see the solar panels a company has installed!”

One customer is Mahindra & Mahindra’s automotive division in Kandivali, Mumbai, which was given one 5 m x 5 m umbrella on a complimentary basis in 2016 to help their building get certified by the Indian Green Building Council.

According to Choksi, a Mahindra automobiles factory elsewhere “had installed solar, but it was ‘invisible.’ Employees, suppliers, customers were not fully aware of the installation and Mahindra’s investments in environmental technologies.”

“If you approach a company to sell solar, you will see at least 13 competitive quotes in front of you. It tells you the state of the industry and how innovation is non-existent. For India to be known as a clean tech innovator, we need to support companies that do not follow the herd.”

Rajan Joshi of Uniphos Envirotronic Pvt Ltd, a division of United Phosphorus crop chemical company, told “We have installed 20 5mX5m canopies earlier this year at our factory in Mahuli, near Vapi, on the side of a highway for INR 4-500,000 each.” The company is one of the leading manufacturers of gas detection equipment.

The umbrellas are employed as a cark park for employees: each can accommodate eight cars or 12 two-wheelers. “The solar panels provide local lighting; we haven’t started net metering yet,” he said.

“We are in the environment business and the devices not only look good but make our employees feel good and motivated,” he added.

Chanchal Mertia of Mahindra in Kandivali told “The device was customised to provide benches for sitting below. We wanted to promote a culture of working in the open. The solar panels provided charging points for laptops. It was initially an attraction because the weather is good between November and February. There was a sump to carry the rain to our rainwater harvesting system. The company plans to go in for some more umbrellas to cover lawns around the building.”


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