Solar power will present the perfect solution for Africa to meet the enormous need for clean water supply: By using green, safe, sustainable, and available resources, and combining it with technological vision, creativity and boldness, tangible inventions can be deployed, solving the greatest need of our time.
The heat shed by photovoltaic solar panels could be captured and used to generate clean drinking water. I understand that this is suited even for saline, brackish and contaminated surface water. It is also believed that this is far more efficient than conventional solar sills. The water evaporates into a membrane and condenses into water. This will be ideal IF major industrial units adopt the technology to save the depleting water resources not only in Africa but, every other part of the world. This will not only supplement the conservation practices but more importantly allow water availability for a longer period than predicted.
This is also a better technology compared to the water conversion from the atmosphere – humidity. The serious drawback of this conversion is that it renders the atmospheric air dry which in my opinion, is not beneficial in the long run.
As I said earlier, the recent pandemic has delivered unusual environmental benefits – cleaner air, lower carbon emissions, freedom for the wildlife and this would be an ideal opportunity for humans to capitalise on.
Efforts seem to be on for large scale demonstration and the success of which will be greatest contribution to mankind.
It looks more attractive even from the construction cost of prototype at Rs.800/ with least maintenance. The principle seems to be based on solar thermal heating – Concentrating Solar Power (CSP) is tracked by large mirror fields which concentrate energy towards absorbers which in turn transfers it thermally to the working medium. Ultraviolet rays of sun kill pathogens in water as well.
Solar Water Disinfection (SODIS) is another application that helps killing/inactivating diarrhoea generating pathogens in water. Ultraviolet radiation of the sun heats up contaminated water in either bottles or PET bottles (exposure not less than 6 hours) and kills pathogens. This suits small units where centralised water supply is not available. It does not however change chemical property, non-effective for water of more than 30 NTU turbidity and understandably during rainy or cloudy days.