Enhancing tilted solar still performance by improving evaporation with a cotton wick and condensation with thermoelectric cooling through experimental and economic analysis

Many nations, particularly those in rural places, are struggling with the freshwater crisis. Recently the best way to produce freshwater is done with solar still. In this study, four different solar stills were built and were labelled as conventional solar still (SSA), solar still with the addition of water cooling on the glass cover (SSB), solar still with the addition of a nozzle inside the solar still (SSC), and solar still with the addition of a solar collector (SSD). The four solar stills will be evaluated and compared under the same environmental conditions in Medan City, Indonesia (Latitude/Longitude/: 3° 47' 3.4908'' N/98° 41' 39.1956'' E). The temperature, freshwater productivity, exergy, energy, and economic analysis will be studied for the four solar stills. From the data, the glass temperature of SSC was higher than SSA in the range 08.00 -11.30. SSD was found to have the highest average energy and exergy efficiency. SSB has successfully increased freshwater production by 28.9% from 0.81 L/m2/day to 1.0436 L/m2/day. Moreover, SSB has the lowest cost compared to other solar stills, which only cost 0.193 $/L/m2.

Cost analysis of different solar still configurations

Experimental investigation of the thermoelectric and double-glazed glass effects on the performance of a solar still

Improving the double slope solar still performance by using flat-plate solar collector and cooling glass cover

The enhancement of the productivity of the solar desalination system, in a certain location, could be attained by a proper modification in the system design. Therefore, different design configurations could be found in literatures. However, the increase in the system productivity with high system cost may increase also the average annual cost of the distillate. Cost analysis of different design configurations of solar desalination units is essential to evaluate the benefit of modification from the economical point of view. The main objective of this work is to estimate the water production cost for different types of solar stills. In this paper 17 design configurations are considered. Systems with higher and lower values of productivity are considered in this investigation. A simplified model for cost analysis is applied in this study. The results show that, the best average and maximum daily productivity are obtained from solar stills of single-slope and pyramid shaped. The higher average annual productivity for a solar still is about 1533 l/m2 using pyramid-shaped while the lower average annual productivity is about of 250 l/m2 using modified solar stills with sun tracking. The lowest cost of distilled water obtained from the pyramid-shaped solar still is estimated as 0.0756LE/l (about 0.0135 $/I) while highest cost from the modified solar stills with sun tracking is estimated as 1.288 LE/ (about 0.23 $/1).

Solar still is one of the economic and eminent ways of desalinating the available sea/brackish water into potable water. However, the distillate output from the solar still is moderate and various researches are being conducted to improve the productivity of solar still. In this research, a novel bottom finned (solid and hollow) absorber basin is designed and developed to enhance the heat transfer between absorber and phase change material (PCM) which further improves the freshwater productivity from the solar still. The results of the investigation are compared with the conventional solar still. The three single-slope solar stills considered developed for evaluating the effect of modification on the freshwater productivity are (i) conventional solar still (CSS), (ii) solar still with hollow finned absorber inserted in energy storage (SSHFES), and (c) solar still with solid finned absorber inserted in energy storage (SSSFES). The investigation results reported that the SSHFES has greater productivity when compared with the SSSFES and CSS. The freshwater productivity from the SSHFES is 4085 mL/m2 day, whereas the freshwater productivity from SSSFES and CSS is 3485 mL/m2 day and 2885 mL/m2 day, respectively. The efficiency of SSHFES and SSSFES is increased by 41.67% and 20.81% relative to the CSS. It is observed from economic analysis that the cost per liter (CPL) freshwater produced by SSHFES, SSSFES and CSS is about ₹ 2.3 ($ 0.032), ₹ 2.5 ($ 0.034), and ₹2.6 ($ 0.036), respectively. The payback periods of SSHFES, SSSFES, and CSS is 6.3 months, 6.8 months, and 7.1 months, respectively. Also, the enviroeconomic analysis conferred that the carbon credit gained from the SSHFES is $189.28 whereas SSSFES and CSS gained only $158.2 and $132.02. Based on the current study, it is observed that the solar still with hollow finned absorber inserted in energy storage (SSHFES) is effective when compared to others and it is viable for potable water production at cheaper costs.

Impact of utilizing hollow copper circular fins and glass wool insulation on the performance enhancement of pyramid solar still unit: An experimental approach

The current work involves experimental investigation on a conventional solar still to improve the productivity of fresh water by introducing the evacuated tube thermosyphon heat pipe. The evacuated tube thermosyphon acts as additional heat source to the solar still. The paraffin wax was utilized as latent heat storing medium, filled between the evacuated glass tube and thermosyphon heat pipe to escalate the fresh water productivity during off-sunshine hours. Two identical solar stills, one with three evacuated tube thermosyphon and another without it, were constructed and tested simultaneously. The solar radiation intensity, volume of fresh water produced, and temperature at various points such as basin water, glass cover, ambient and evaporator and condenser section of the heat pipe were measured. The utilization of evacuated tube heat pipe as an additional heat source increases heat input by 84.5%. The increase in heat input upsurges the gathering of fresh water by more than three times when compared to the conventional solar still. Accumulative fresh water productivity from the modified solar still was 215.7% higher than fresh water productivity from the conventional solar still. The modified solar still was capable to yield fresh water during no sunshine hours of evening as an effect of utilization of phase change material. The study suggests that direct coupling of the evacuated heat pipe to the solar still performs well in terms of fresh water yield and the same can be employed for household purpose.

In this work, a new idea of using the wick material inside the solar distiller is provided. This paper introduces a new mechanism of using wick materials inside the solar stills. The main aim of the proposed mechanism is to improve the solar still productivity. This was achieved by creating specified number of cracks on a parallel upper basin liner with an offset of 3 cm from the original basin liner of the solar still. The basin saline water was kept at 2.5 cm over the original basin liner. Besides, the upper basin liner was covered by a wick material. Moreover, wick cords were dangled from the cracks and edges of the upper basin liner to withdraw the saline water and keep the wick surface wet all the time. This design prevents wasting energy and optimizes the use of wick inside the solar still because the wick cords withdraw an amount of saline water equals to the evaporated quantity without excessing or removing hot water. So, there is no loss of hot water. The tested parameters in this study were the different types of wick materials (cotton wick and jute wick) and different numbers of cracks/cords (9, 16, 25, and 35 cords). Experimental results obtained that the thermal performance of the cords wick solar still was superior than that of the conventional solar still. In addition, using the jute wick provided constantly better performance of cords wick solar still than the cotton wick material. Moreover, the best performance of cords wick solar still was obtained at 25 cords, where the increase in productivity of cords wick solar still over the conventional solar still was 122 and 118% when using jute and cotton wick, respectively. Also, the daily thermal efficiency of cords wick solar still was 53% (at 25 cords) compared to 34.5% for the conventional solar still.

This study aims to augment the performance of a solar desalination unit. To experimental examine this idea, a modified solar still with three different microparticles doped in black paint-coated absorber were designed, fabricated, and tested in Jaipur, India. Three different microparticles such as copper, aluminum, and tin with particle size of 50-80 μm with weight concentration of 10% were doped in black paint and then coated on the absorber of solar still. The coated absorber of solar still were compared with the conventional solar still without any microparticle coating to obtain the effect of different coating materials on the water productivity, thermal performance, economic, and environment-economics analysis of solar still. The result showed that under the water depth of 1 cm, coating of copper, aluminum, and tin on absorber augmented the full-day water yield by 33.13, 22.18, and 11.53%, compared to conventional solar still without any coating. In addition, full-day energy and exergy efficiency of solar still with copper-coated absorber exhibited maximum values compared to all other solar stills, owing to the higher thermal conductivity and excellent solar-thermal conversion behaviors of copper. The cost of water per liter estimated through economic analysis was found to be US $ 0.0074 for conventional solar still, which was significantly reduced to US $ 0.0066 in the case of solar still with copper-coated absorber along with the payback time of 2.7 months. The environment-economic assessment estimated that solar still with copper-coated absorber plate has reduced the 13.19 tons of CO2 emission. It is concluded that augmented heat transfer rate from water basin to inner glass surface through utilization of microparticle coating would pave a pathway to develop energy-efficient low-cost solar-based desalination system.

In the following experimental study modifications were carried out into a stepped solar still, considerably increasing the distilled water productivity. Objective function in present study is the comparison between of an active stepped solar still provided with modifications in a new water cooling circulation depending upon an active mode by means of a PV cell incorporated for a stepped solar still, with a conventional solar still without water circulation. In the study the results of glass cover temperature, basin temperature, and fresh water productivity are collected for both stepped solar stills. Also, the solar radiation rate for a period of June 2018 to November 2018 have been carried out in order to optimize the stepped still performance and its yield as well. It was found that, these additions and modifications highly enhance the evaporation and condensation, so distillate yield was augmented. It was found that, daily distilled water productivity reached about 7.21 l/m2 day for the stepped solar still with water circulation. While corresponding value was 4.45 l/m2 day for the conventional stepped solar still at the same water depth (2) cm at summer times and 6.41 l/m2 day for the stepped solar still with water circulation and 3.5 l/m2 day for the conventional stepped solar still at winter times also at the same water depth. The increase in daily distillate water productivity for a stepped solar still with a PV and water circulation is about 78.24 % higher than that of a conventional stepped solar still. Moreover, the average efficiency of daily freshwater productivity is 42.84 % for a stepped solar still with water circulation, while it was 37 % for a conventional stepped solar still, at the same water depth 2 cm at summer and 40.5 % for a stepped solar still with water circulation and 34 % for a conventional stepped solar still at winter times. The present study held under the climate conditions of Egypt at Faculty of Engineering-Tanta University, Egypt.

Study on the effect of oil palm shells on fresh water productivity of double slope solar still

Employing convex shape absorber for enhancing the performance of solar still desalination system

Thermal design strategy for enhanced freshwater harvesting with interfacial evaporation

This study experimentally investigates the integration of a flat plate solar collector and a condensation chamber into a basin solar still. Three prototypes were designed and constructed for evaluation: a basin solar still coupled to both a solar collector and a condensation chamber, a basin coupled with a solar collector, and a simple basin solar still as a reference. The experiments, conducted from July 24 to 28, 2016, at the UDES site in Bouismail, Algeria, used seawater from the Fouka region. Solar radiation emerged as the primary influencer on the solar desalination system, with active solar stills, particularly those equipped with a flat plate collector, showing significant temperature increases. Daily cumulative production analysis revealed the condensation chamber as a significant contributor, representing 58% of total production. Incorporating a flat plate collector resulted in a 110% increase in daily production compared to the conventional solar still. Simultaneously incorporating both the flat plate collector and the condensation chamber showcased an impressive 176% increase in daily production. Daily production quantified at 5.9 kg/m2 for the active with a condensation chamber, 4.5 kg/m2 for the active solar still, and 2.1 kg/m2 for the simple solar still. Economic analysis indicated that the active solar still with the condensation chamber enables more cost‐effective freshwater production than the active solar still alone. Water analyses demonstrated the efficiency of solar distillation, converting high‐salinity saltwater (31.4%) into exceptionally pure distillate (0.00%).