IISc scientists develop solar-powered desalination system

Two scientists from the Indian Institute of Science (IISc) have developed a low-cost and low-maintenance solar hybrid desalination system that converts sea and brackish water to potable water. 

Talking about the inspiration behind the desalination system,  Dr Ravinder Kumar from the Department of Electronic Systems Engineering (DESE), IISc said, “In 2004 when I was in Chennai, there was a huge water crisis and people were struggling to even get water tankers to their homes. That was my starting point to think about this. There was a vast amount of sea water next door but people were still suffering.”

The system uses flash evaporation and subsequent condensation to desalinise sea water. “Evaporation of water under normal atmospheric pressure requires more energy than flash evaporation. Through flash evaporation, what we did was vary the pressure inside the evaporation chamber so that water can evaporate at any temperature, not just at 100 degrees,” said a release from IISc. The energy required for flash evaporation is supplied by solar concentrators, which are essentially Scheffler dishes used as concentrators of solar energy. The concentrators raise the temperature inside the evaporation chambers, the press release added.

Subsequently, to pump water into chambers, photovoltaic panels are used as a source of energy. According to Dr Kumar, the success shown by this system shows promising signs that “the problem of clean drinking water can be solved in any coastal area where seawater and sunlight is available freely.”

Construction of massive desalination plants incurs huge costs and makes it unaffordable for developing countries. Also, using fossil fuels to power these desalination plants are expensive and results in environmental damage in the long run.