Clean water photovoltaic sensor for solar disinfection in developing countries

One of the limitations for the widespread use of solar water disinfection technologies in developing regions is the lack of low-cost clean water sensors. A new type of low-cost sensors using photovoltaic solar cells that provide information about received irradiance, temperature, UV irradiance and sunshine duration is presented. A key aspect of the design is the UV irradiance measurement. Two identical cells are used, one of them with a low-cost UV-blocking filter on top, so the total UV irradiance can be calculated as the difference between the two solar cells outputs. The first cell would be measuring UV–vis–NIR and the second only vis–NIR. The UV filter material was explored and a low-cost architectural film was selected. Materials costs for the first prototype were of approximately 4€ excluding labour. Initial testing also included experiments with real polluted water and Escherichia coli, showing the feasibility of the new design.