Thermal efficiency improvement of a solar desalination process by parabolic trough collector

Abstract

Nexus water/energy security is one of the main global challenges for the future generation. Solar distillation (thermal process) represents a sustainable solution to water shortages and energy crisis in the world especially in the Middle East and North Africa region. The technique is based on a evaporation–condensation process via heat delivery through a cylindrical parabolic collector to a thermal energy storage, in the form of sand integrated into the solar still, to maximize water production efficiencies. It is a technically feasible and operational method. Results suggest that the additional solar collector flux has a direct impact on the increase in average sand and seawater temperature particularly over the period between 12 p.m. and 4 p.m. Seawater temperature increases by >26.6%. The energy stored quantity delivered for the distiller basin grows proportionality with the sand temperature, which is depending directly for the solar collector absorber temperature. The difference between the both temperatures defines a decreasing rate of −19%. The daily water production by the hybrid solar distiller is 6.5 l/day, it represents an increase of +91% compared to the traditional concrete solar still production (3.4 l/day), for the same geometry and meteorological conditions. HIGHLIGHTS Renewable energies integration in the seawater distillation process.; Improvement of the water evaporation phenomenon using a parabolic trough solar concentrator.; Solar still efficiency optimization by the thermal energy storage integration.; New design of the greenhouse still flow control principle, materials.; Proved the efficiency of the hybrid still compared to the concrete still in a Mediterranean climate.;

Keywords

• cylindrical parabolic collector
• parabolic trough collector
• solar distillation
• solar still
• thermal energy storage