Performance analysis of a basin-type solar still during harmattan

This study investigates the variational effect of climate factors on the productivity of a basin-type solar still during the harmattan season under the tropical savanna climate. The study was extended to examine the influences of selected climatic, operational, and design (COD) parameters on productivity. Additionally, the efficiency of solar still in removing water impurities during harmattan was also investigated. Explorative data and statistical analysis, and laboratory testing methods were used for these investigations. Results show that seasonal effects of harmattan can either increase or lower productivity. The effect of wind speed on productivity was not clearly defined during the harmattan season. Although high irradiation is essential for increased productivity, its effect is modified by other factors. Water temperature is the most significant to productivity amongst selected factors studied via the design of experiment (DOE). Moreover, the effect of harmattan on the water quality produced was not established. The main contribution of this work is the insights generated for both qualitative and quantitative reliability performance of a basin-type solar still under prevailing climate conditions.

Effect of different basin materials on the performance of hemispherical distiller with mirrors and energy storage material

Numerous studies are being conducted on solar desalination systems with creating new designs to improve the efficiency and yield of these systems. Hemispherical solar still has a relatively large throughput because of its large exposure and evaporation surface areas compared to the other distiller designs. To get the optimal conditions of the parameters that provide the highest productivity of the hemispherical still, three hemispherical basin stills were fabricated and tested. The experiments were performed in three stages: In the first one, the traditional hemispherical solar still THSS (a reference distiller) was compared by THSS with internal reflective mirrors (THSS-IRM). In the second stage, the effect of using different basin metals (THSS with basin metal of zinc (THSS-IRMZ) and basin metal of copper (THSS-IRMC)) with internal reflective mirrors was studied. In the third stage, the two distillers were investigated under using energy storage medium (30 g/L sand grains for each). The THSS with internal reflective mirrors, basin metal of zinc, and energy storage medium is abbreviated by THSS-IRMZSG. Also, THSS with internal reflective mirrors, basin metal of copper, and energy storage medium is abbreviated by THSS-IRMCSG. Moreover, THSS with internal reflective mirrors and energy storage medium is abbreviated by THSS-IRMSG. The results showed that the combination of using internal reflective mirrors, basin material (copper) and energy storage medium provided the best improvement of hemispherical distillation device. The maximum cumulative yield of THSS-IRMCSG was 11.9 L/m².day, while the reference distillation device gave a total yield of 4.65 L/m².day. So, the productivity was improved by around 156%.

Productivity Enhancement of Solar Water Desalination Unit Using a Solar Electric Water Heater

The biggest problem faced by the world these days is pure drinkable water, and in a few years pure drinkable water will not be easily available, as it is becoming brackish and saline due to pollution. By using solar energy, a solar still can produce pure water which can be used for drinking, cooking, and also for industrial purposes. In this research, a solar still based on clean technology using solar energy to drive the system is used. It can be operated easily and with an approximately negligible maintenance cost. A pyramid solar water desalination unit with modification of the solar electric water heater (used to increase water temperature) is developed to increase the water yield per day. A theoretical model of the solar still unit with and without an electric water heater is developed and performance is compared. Based on this theoretical design, fabrication is carried out and experiments are performed to predict the overall output. It is observed that the output distilled water has a TDS (total dissolved salts) value much lower than the TDS of groundwater. Additionally, the average output of a solar water desalination unit with an electric water heater is found to be enhanced compared with the unit without an electric water heater.

Experimental and Numerical Investigation of a Semispherical Solar Still, Chamber Stepwise Basin, with and without a PV Powered Electrical Heater

The world's need for drinkable water is increasing with a growing population. The desalination process using solar energy is the cheapest and most straightforward method that can be used to generate pure water from saline water by utilizing energy from the sun's free heat source. A semispherical and chamber stepwise basin solar still with an inclined glass cover, with and without PV powered electrical heaters as another power source can increase the rate of evaporation of saline water, thus increasing the productivity of semispherical solar still. In this investigation, a conventional solar still and semispherical solar still with and without PV-powered electrical heaters were invented and worked in parallel with the experimental setup to make a good comparison between these models. The experimental results show that stepped semispherical with PV-powered electrical heater and without PV-powered electrical heater solar stills enhanced the productivity of freshwater from a conventional solar still by 156.6% and 72.5%, respectively. The theoretically simulated model is obtained using Mathcad software, and is compared with experimental results. Semispherical solar still productivity increases with increased solar intensity and with a PV-powered electrical heater as an additional power source. The theoretical results concluded from the mathematical model are in good agreement with experimental results.