Mathematical Modeling and Experimental Investigation of a Controlled Flow Solar Water Disinfection System Using Flat Plate Solar Collector

A biologically contaminated water can be disinfected by different methods like thermal energy, UV light and addition of chemical reagents like chlorination and ozonation. Solar energy can contribute in thermal applications for water disinfecting techniques. A controlled flow solar water disinfecting system was manufactured, tested and numerically investigated. The system is simply constructed of a 2.34 m2 flat-plate solar collector and the outlet flow temperature is controlled by a solenoid valve to a disinfecting temperature level. The outlet hot disinfected water is used to preheat the inlet contaminated water through a shell and tube heat exchanger. Different disinfection temperatures are considered with their corresponding heating period of time. The system is numerically simulated to investigate the annual performance and its life cycle savings. The simulation model was validated by measured data with a close agreement. The simple system at 60 °C disinfection temperature can daily produce 171 liter of clean water by square meter of solar collector where it reduces into about 39 l/m2 at 90 °C. That is corresponding to 81.5 and 1.1 l/m2 per kWh of incident solar radiation respectively. A life-cycle savings analysis obtained that the flat-plate solar collector seems to be efficiently and economically used in solar water disinfecting systems. Based on the system outputs and economics, a large-scale system can be considered in commercial use.