A floating solar still inspired by continuous root water intake

Estimation of convective heat transfer coefficient and water-productivity in a tubular solar still – CFD simulation and theoretical analysis

This present work is aimed to examine the effect of mass flow rate on distillate output and performance of a solar still in active mode. Outdoor experiments were conducted at the coastal town, Kakinada (16°93′N/83°33′E), Andhra Pradesh, India. A solar still with a 30° of fixed cover inclination, 1 m2 of effective basin area, and a flat-plate collector (FPC) with an effective area of 2 m2 were used. An attempt was also made earlier in passive mode to optimize the water depth for the same solar still for maximum yield and distillation efficiency. For the passive still, it is observed that the capacity of heat storage and heat drop are significant parameters that affect the still performance. For the selected still design, the study reveals that 0.04 m water depth is the optimum value for specific climatic conditions. In the active solar still, with the optimum water depth, different flow rates of 0.5, 1 and 1.5 L/min are considered through FPC. It is observed that both the mass flow rate and the variation of internal heat transfer coefficients with the mass flow rate have a significant effect on the yield and performance of the still. The experimental results show that the combination of 1.5 L/min mass flow rate and an optimum water depth of 0.04 m leads to a maximum yield for the active solar still. The enhanced yield of the active solar still is 57.55%, compared with that of the passive solar still, due to increase in area of radiation collection and more heat absorption rate.

The shadow effect is one of the major problems hindering the operation of solar energy‐based systems and affects the performance of solar stills. The shade cast by the still's lateral walls on the basin reduces the solar‐exposed area and reduces the daily distillation yield. This article deals with an experimental study to evaluate the shadow effect on the conventional solar still (CSS) performance. A comparative analysis was conducted between the single‐slope CSS and the modified one (modified solar still [MSS]) with three glasses. Therefore, outdoor experiments were performed in hot and cold weather conditions in Adrar—Algeria. The results showed that replacing wooden walls with transparent glass is not always efficient, and the still's thermal performance depends on the weather conditions. On the summer day, the daily productivity reached 3.57 kg/m 2 for the CSS and 4.42 kg/m 2 for the MSS (a reduction of about 24% compared with the MSS). On the winter test day, the glass side walls appeared to negatively impact the MSS distillate yield, which was 5.55% lower than the CSS yield (2.57 vs. 2.71 kg/m 2 for CSS). Energy and exergy analysis show that the MSS is more efficient than the CSS on summer days, whereas the opposite happens on winter days.

Performance of solar still units and enhancement techniques: A review investigation

Exploitation of solar energy collected by solar stills for desalination by membrane distillation

Efficiency improvement of solar stills through wettability alteration of the condensation surface: An experimental study

A new optimized artificial neural network model to predict thermal efficiency and water yield of tubular solar still

Experimental parametric study of membrane distillation unit using solar energy

Solar stills are widely recognized as a cost-effective and eco-friendly solution for transforming brackish water into potable water. Although solar energy shows promise, it has yet to be widely adopted due to its lower productivity. This paper presents an experimental investigation to enhance the performance of a single slope solar still using phase change material (PCM) and external reflectors. Many outdoor experiments have been conducted for three cases including: solar still without PCM, Solar still with PCM, and solar still with PCM with external reflectors. Also, the effect of water depth inside the still is examined. The performance of the four cases is evaluated and compared under the meteorological conditions of Baghdad City, Iraq. The results showed that using the PCM improved the Accumulated yield of the conventional solar still by 23% and 14 % for water depths of 2 cm and 3 cm, respectively. Also, the results revealed that using the external reflectors improves the Accumulated yield by 15% for the still with PCM, respectively.

Artificial intelligence vision technology application in sustainability evaluation of solar-driven distillation device

Performance improvement of a tubular solar still using V-corrugated absorber with wick materials: Numerical and experimental investigations

Water is the basis of the existence of all kinds of life, so obtaining it with good quality represents a challenge to human existence and development especially in the desert and remote cities because these areas contain small populations and water purification requires great materials and huge amounts of fossil fuels resulting pollution of the environment. Cheap and environmentally friendly desalination methods have been done by using solar distillations. Passive solar stills have low yields, so in this research, the problem is overcome by connecting four heat pipes which are installed on the parabolic concentrator reflector with passive solar still to increase the temperature of hot water to more than 90°C, as a result, the yield increases. An extensive theory is studied to manufacture two systems: the first consists of passive solar still has dimensions are 1000 mm × 500 mm and the glass cover tilted at the angle 33°. It is approximately equal to the latitude of the city of Baghdad [(Latitude: (33.34° N) Longitude: (44.4° E)]. This gives 5.04 kg/m2.day, the second solar still which is associated with 4 heat pipes gives a water yield of about 7. 2 kg/m2.day. This means that the improvement in the daily production of distilled water is 50 % over the productivity of the passive solar still All results above are calculated when the depth of water is 1. 5 cm. In addition, heat balance for each part of the system is achieved and calculations of the performance of the solar still are done by using the program in the language of Matlab. All these results are compared with the experimental ones of different depths of water (1.5 cm, 2 cm, 3 cm, and 4 cm) which are taken from the experimental part to ensure the system reliability at different weather conditions in Baghdad throughout the year and to give a good approach. The system associated with heat pipes gives promising results and can be widely used for its abundant productivity and durability of its components. (TDS) and (pH) value are carried out in the laboratory and it is found that water is safe and pure for drinking.

Dwindling potable water is a big concern for the whole world in general and developing nations in particular. Solar still is found to be suitable for the production of potable water at low cost, especially in the arid regions. In view to improve the distillate output of the solar still, the augmentation of the sensible and latent heat, a storage material was needed. For the purpose, wax filled metallic finned cups were used. In this paper, an attempt was made to investigate (experimentally and theoretically) the performance of a conventional solar still integrated with wax filled metallic finned-cups (MSS). Outdoor experiments were conducted on conventional solar still (CSS) and CSS augmented with wax filled metallic finned-cups, in the month of January and February 2019, at Raghogarh, Guna ( 24º39'N, 77º19'E, India). Linear regression model proposed by Kumar and Tiwari was used to evaluate the performance of solar stills. An improvement of 15.63 and 16.95% in evaporative and convective heat transfer coefficients (from water to condensing cover) have been observed in MSS, as compared with the CSS respectively. It was found that the overall efficiency of MSS increased by 24.64% in compared with the CSS.

Solar still only finds its application in remote and low population density areas due to its low productivity. This paper aims at improving the freshwater output of single-slope solar still (SS) by coupling it with an evacuated tube collector (ETC). The performance of this ETC coupled still is further enhanced by using a heat exchanger (HE), an internal reflector (IR) and an external condenser. The experiments are carried out with various still modifications, namely, SS (HE+IR+condenser), SS (HE+IR), SS (HE+condenser), and SS (HE only). These modifications are done to expedite the rate of evaporation of basin water and the rate of condensation of the water vapors. The performance of these four arrangements is simultaneously compared with a conventional still on all testing days. Two solar stills of similar dimensions are fabricated to carry out the experiments. One still is applied with modifications while the other is kept conventional. The maximum productivity of 2259 ml and an efficiency of 33.4% is achieved for SS (HE+IR+condenser) as per the experimental results. The results indicated that using a HE and an IR in a solar still had a considerable impact on the still productivity but an external condenser had a little effect on the still performance. The results also indicated that the increase in overall efficiencies of all four modified designs is very small in comparison to conventional still. Abbreviation: ETC: Evacuated tube collector; SS: Solar still; PCM: Phase change material; CS: Conventional still; FPC: Flat plate collector; ASv: Annual salvage value; HTF: Heat transfer fluid; Sv: Salvage value; CPL: Cost per liter; MCannual: Annual maintenance cost; CRF: Capital recovery factor; Pa: Annual freshwater production; SFF: Sinking fund factor; A: First annual cost; TAC: Total annual cost; C: Capital cost; HE: Heat exchanger; t: Bank interest rate; IR: Internal reflector; n: Average life of still.

Energy, exergy, energy matrices, exergoeconomic and enviroeconomic assessment of modified solar stills