India: 640 m² Collector Area and 40,000 Litres of Tanks Paid Back in 4 Years

 Solar hot water system at L’Oreal`s factory in Pune Five years ago, French cosmetics giant L’Oreal commissioned one of the largest indirect solar water heating systems in India for its factory in Pune, located in the western part of the country. Each day, the fully automated and pressurised system heats up around 32 m3 of water to 55 OC in order to wash the plant’s process vessels. The total investment amounted to INR 7.5 million (EUR 115,000), which was paid back within four years. Its back-up system consists of a diesel-fired boiler.
Photo: Racold Solar

All project steps, including design, supply and installation were done by Racold Solar, a collector and tank manufacturer also located in the city of Pune. The turnkey system was built according to customer requirements, such as not letting hot process water get in contact with copper tubes. This means that all piping had to be made of stainless steel.

All in all, 320 flat plate collector panels with a collector area of 640 m² have been installed on two different factory roofs. There are four buffer tanks of 2,000 litres each and one 32,000 litre main tank to store the hot water. It was necessary to split up the tanks across the solar circuit because it was not feasible to install the entire collector field on one roof.

 Schema of solar hot water system at L’Oreal`s factory in Pune Schema of solar hot water system at L’Oreal`s factory in Pune: The solar circuit and the main 32,000 litre storage tank have been separated by a plate heat exchanger.
Figure: Racold Solar

The complete solar system has been automated by the use of three electronic control panels, which - along with Thermocouples (5 Liquid Level Controllers) and 10 pumps - direct the flow of water through the system. According to L’Oreal’s office in Pune, the solar installation helps to save 170 litres of diesel oil per day, and has already paid back in its fourth year.

The Management of L’Oreal India emphasises the pivotal importance of climate change mitigation and adaptation. Investing in energy efficiency and renewable energy could well be the strategies to face these challenges of our time. The L’Oreal case study seems to be a clear example for the rapidly changing attitude of Indian industries towards environmental and energy issues.

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This text was written by Jaideep Malaviya, an Expert in Solar Thermal based in India (


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