Performance analysis of single basin solar distillation cum drying unit with parabolic reflector

In this communication, it is attempted to utilize the heat losses from the basin of a distillation unit for drying ginger in a drying chamber attached underneath the distillation unit. Experimentation has been made on single slope single basin solar distillation-cum-drying unit with parabolic reflector. Thermal performance of distillation and drying units is studied at varying water depths in the distillation unit. Based on the experimental data, heat transfer coefficients are evaluated by using linear regression analysis. Average convective heat transfer coefficients have been observed as 5.75 and 4.8 W/m2 oC for distillation and 3.64 and 2.9 W/m2 oC for ginger drying at a water depth of 4 cm and 6 cm. Evaporative and radiative heat transfer coefficients for distillation are observed to increase with the increase of solar radiation and ambient temperature. Average 2 l/m2 distillate and 2 kg/m2 dried ginger is obtained from the system at 4 cm water depth with an estimated cost of Rs. 2.55 per litre of distillate and per kg of dried ginger. Overall energy and exergy efficiency of solar distillation is found higher at lower water depth. Experimental error for solar distillation and ginger drying is also evaluated in terms of percent uncertainty.