My experience at Solar Decathlon India 2025

Solar Decathlon India (SDI) organizes an annual competition where student teams from Indian institutes are invited to partner with the real estate industry to develop eco-friendly solutions for real building projects that are affordable, and market ready. This is a seven-month long challenge where student teams compete in 6 categories and are evaluated over 10 contests, as shown in the illustrations below. Their solutions need to excel in each of the 10 contests, which makes this a decathlon.

SDI 2025, held at Infosys campus in Mysore, was the 5th edition with participation of 2000 plus students from 154 engineering and architecture institutes across India. There is increasing participation of all stakeholders- students, faculty mentors, industry partners and project partners with each passing year for this event.

I had met Prasad, Director of SDI in one of the climate talks in Bengaluru on low carbon buildings. After the talk I had email correspondence with him on technical queries in preparation for my past article- Benchmarks for eco-friendly residential buildings in India. During the correspondence Prasad appreciated the writings on this website and extended the jury invite which I happily accepted. I was invited as Grand jury member, being part of the 10-member panel to assess the six divisional finalists and pick the final winner from this competition.

Few thoughts on Infosys campus, Mysore

I had known that Infosys use their Mysore campus for training their new hires from across India and had built a big campus for it. But you truly appreciate the massive size of the campus (spread over 350 acres) when you see it for yourself. The campus has lush greenery with very good maintenance of its campus roads, sidewalks and lawns, as you can see in the pics below. The size of the campus is evident from the need to use cycles to move around in the campus! There are 91 residential buildings alongside auditoriums, recreational sports facilities and multiple food courts.

To digress a bit, the one thing which I didn't like in the campus was Infosys going overboard to impress their American clients! Some of the auditorium and conference building architecture were mimicking iconic buildings in US, one in particular copying the US White house. Instead, Infosys could have used this campus as an opportunity to showcase rich Indian architecture heritage. The lawns were manicured just like you see in US tech campuses. All the classrooms in major buildings were named after American scientists. All this points to our need to get western validation, entrenched in our colonial mindset. Excluding this factor, Infosys has built a world class campus infrastructure with lot of eco-friendly initiatives implemented on campus.

Highlights from the event

The students were very upbeat and keen to show their demo models and design presentations to the jury. Their energy was infectious which made everyone cheerful and curious to learn more about their work.

In the session on residential cooling retrofit two projects caught my attention. One project was on window retrofit (pic below) where the students designed a low cost, modular fins system which can retrofitted into existing window columns in the houses. The water is filled into the fins from the top and the fins, made of a composition of cement (for strength), clay (for cooling) and sawdust (strength and porosity), acts as a thermal mass to absorb the heat from the surroundings. Number of fins can be adjusted, and water can be drained out from the bottom when cooling is not needed. The project team claimed that interior temperature reduced by 2.5°C over an hour with this system which is good for a passive cooling strategy. They plan to improve the fin aesthetics and bring this product to the market at an affordable retail price of ₹ 5300 per unit. This product seems to be an effective low-cost solution to get some relief from the scorching Indian summers in the future.

The other project was an active cooling solution where the students built a portable cooler (pic below) which had improvements over the existing desert coolers in the market. The existing coolers rely on simple evaporative cooling where water in the tank trickles over the honeycomb pads in the back and air is pushed through the pads using fans. In this cooler, they have a double-stage evaporative cooling mechanism, where the water in the tank flows through the terracotta beads in the first stage and then through the honeycomb pad to maximize the evaporation rate for enhanced cooling efficiency. This product has the potential to disrupt the cooler market segment in India with their planned price point range of ₹ 8000-10,000 per unit.

Other highlights from the event were the pitches from startups for Climate Smart innovation award. The startups were working on a variety of solutions ranging from modular, chemical-free wastewater treatment system to replacing timber with rice straws for engineered wood industry to multipurpose all in one building wall coatings. I was really impressed with the startup Pavakah Energy where they are developing a thin photovoltaic film which can be applied on any surface to convert the surface into a solar panel. This versatile approach makes it possible to harness solar power in places like walls of residential and office buildings, car exterior etc. They claim that the material of the film is more recyclable than conventional solar panels on rooftops. Stay tuned for a forthcoming article doing a deep dive on this technology.

Among the six divisional categories in the competition, I appreciated the presence of two categories -community resilience shelter and construction worker housing. The former category delivers housing solutions to the underprivileged people at times of distress, and the latter provides dignified accommodation to the people who are the backbone of infrastructure development in India, but their needs are woefully neglected. Both categories are a starting point in addressing climate and social injustice in India in the built sector.

Jury evaluation

The jury process in picking the final winner was no easy ask as it was not apples to apples comparison between the 6 categories. It was interesting to observe some jury members gave importance to social factors of the projects while others like me gave importance to the technical viability. It was a good personal learning experience for me in reaching a consensus when there are multiple evaluation criteria and differences in opinions among the jury members.

The final winner was Team Anvaya from the Construction Worker Housing Division. This team was represented by BMS College of Architecture, Design and Planning with B.M.S. College of Engineering as the partner institution. This team proposed a promising and investment-worthy building design for Rohan Builders (India) Pvt. Ltd.

Concluding note

This event demonstrated the power of industry-academia collaboration in bringing affordable innovations to the market. SDI has taken a lead on this front and is fostering the next generation of architects, engineers, and entrepreneurs who can deliver eco-friendly buildings and help India achieve its climate goals.

This work is licensed under CC BY-SA 4.0