High-Temperature Distillation Using N-Parallel Evacuated Tube Collector Integrated With Double Slope Solar Still in Force Mode

In the present communication, a performance investigation of a double-slope solar still augmented with parallel evacuated tubes under forced mode is carried out for a modified geometry. A comprehensive mathematical model is used for the numerical simulation using the experimental data and incorporating the effect of variable flowrate, water depth, and the number of tubes. An optimum flowrate range ∼0.006–0.007 kg/s/tube is found irrespective of the number of tubes and basin water depth to extract optimal energy. The flowrate is validated with other experiments, carried out by various authors. At optimal flowrate with ten tubes and 0.005 m basin water depth, the system yields 6.644 kg, while overall energetic and exergetic efficiencies are observed as ∼33.8% and 4.9%, respectively. With an increase in the tubes as 20 and 30, the respective yields are found to be increased by ∼2.64% and ∼6.62% for nearly the same collector output temperature attainable (≈98.5°C), while the energy and exergy efficiencies decreased significantly by ∼24.6% and ∼38.6%, compared with ten tubes arrangement. Daily yield and overall exergy efficiency are increased by 13.3% and 19.3%, respectively, using a diffused reflector.