Solar Distillation Unit Research Articles

Effect of a black paint coated double layer cellulose sponge as an absorber in a solar interfacial distillation: an experimental investigation

ABSTRACT In the recent past, direct solar energy-based distillation for the production of freshwater has been the subject of extensive research. Nevertheless, the outdoor experimental study did not thoroughly investigate the incorporation of the interfacial absorber concept in conventional solar distillation. Therefore, the impact of a simple black paint spray coated double-layer cellulose sponge on the freshwater yield of a solar distillation system is examined in this work. The modified top layer of the cellulose sponge exhibited an increase in the average absorbance of solar radiation from 27.59% to 86.88% in the wavelength range of 200–2400 nm. The maximum freshwater yield of the black paint-coated cellulose sponge-based floatable interfacial absorber (Unit II) was found to be 3.85 L/m2/day, which was 29.27% higher than that of the conventional solar distillation unit (Unit I) upon 4 days of experimental investigation. Comparably, Unit-II outperformed Unit I with an overall evaporation efficiency of 46.08%, which was 10.22% higher than Unit I. Furthermore, Unit II attained an exergy efficiency of 64.24%, surpassing Unit I by 28.5%. Therefore, in order to address the water shortage in rural areas of society, this work would assist researchers in designing and developing an effective interfacial absorber.

Sustainable and clean water distillation by parabolic dish collector and different heat absorber and thermal storage materials: An experimental study

In this study, an integrated solar distillation unit with a parabolic dish collector and a spherical solar water distillation unit is designed. The use of parabolic dish collector increases the evaporation rate of the saltwater in the lower chamber (basin) of the spherical distillation unit considerably. The performance of solar water distillation system is investigated for different types of basin material, including copper, zinc, and iron. In the second part, the gravel is used in the copper basin of solar distillation system as the thermal energy storage material. The thermal efficiency, water productivity, exergy efficiency, and freshwater production cost of the integrated solar distillation system with different types of basin materials are studied. The thermal efficiency of the integrated solar distillation system with the copper, zinc, and iron basins was 13.97 %, 10.72 %, and 9.88 %%, respectively. The water productivity of the integrated solar distillation system with copper, zinc, and iron basins was 2.592 kg, 2.27 kg, and 1.825 kg, respectively during 9 h of experiment. The exergy efficiency of the integrated solar distillation system with the copper basin was better than the zinc and iron basins. The gravel can increase the productivity of solar distillation system up to three times in the sunset and night hours.

Carbon nanoparticle facilitated functional pyramid solar distillation unit for wastewater treatment

This paper proposes an efficient treatment of reverse osmosis reject (RO reject) and kitchen wastewater (KWW) in a locally developed single-stage functional pyramid solar distillation unit (FPSDU). The working mechanism of the designed and developed solar distillation unit, its specifications, treated water characteristics, novelty over conventional units, and economic analysis have been discussed in detail. The concept of coating glass beads is attempted for its functional application in solar still for generating photothermal heat. Carbon nanomaterials (CNP) coated glass beads were used as a heat storage medium. FPSDU produced approximately 6003 mL/m2day of treated water for KWW and 5868 mL/m2day for RO reject wastewater vis-a-vis output of 3000 mL/m2day for conventional solar distillation unit with an input of 7000 mL/m2day of wastewater in each case. This demonstrates that the FPSDU shows an improved performance than conventional distillation units, recovering about 85% of the treated water from KWW and RO reject wastewater as compared to 43% for conventional distillation units. The basin surface showed no signs of corrosion and the coating remained stable even after multiple cycles. The treated water met the criteria as per Indian standards, free with microbial contamination and can be used for different non-potable uses. Findings of the current research supports the improved effectiveness of FPSDU for RO reject and KWW treatment with immobilized carbon nanoparticles.

Experimental and numerical simulation of solar membrane distillation and humidification – dehumidification water desalination system

In this study, a novel solar hybrid air-gap membrane distillation and humidifier-dehumidifier desalination (AGMD-HDD) unit was designed and investigated. In this proposed system, photovoltaic panels were used as the source of electricity in the AGMD-HDD hybrid system. The present work was conducted to explore experimentally the hybrid system's performance within 12 months and simulated numerically using TRNSYS software. The simulated results were in good agreement with the measured values. The flowrate of produced purified water from the solar AGMD-HDD hybrid system were 21.29 kg/h and 11.76 kg/h in the summer and winter seasons respectively. The specific thermal energy consumption (STEC) varied from 60 kWh/m3 to 310 kWh/m3 in summer and 87.12 kWh/m3 - 605.2 kWh/m3 in winter. Freshwater cost estimation using the solar AGMD/HDH system showed a remarkable decrease in freshwater production up to USD 14.32/m3. The gained output ratio (GOR) and the system competence reached 5.33 and 91.03% in summer using a seawater flow rate of 600 kg/h. The total reduction in CO2 emissions was 32 tons in winter and 43 tons in summer seasons.

Development of paraffin wax & used cooking oil based composite thermal energy storage for efficient potable water generation in a solar distillation unit

The purpose of this study is to develop a novel composite thermal energy storage system (CTESS) using blends of used cooking oil (UCO) and paraffin wax (PW) and experimentally investigate its effect on the performance of solar still for effective seawater desalination. The CTESS was developed by mixing UCO with PW in various volume ratios and the volume ratio of UCO and PW was optimized at 1:1. The objective was to examine the performance of the solar still with used cooking oil and paraffin wax (SSUCO) and compare it with a conventional solar still (CSS) without any energy storage. The investigation was carried out experimentally, and the results show that the SSUCO significantly enhanced freshwater production compared to CSS. On the first day, the overall freshwater production from SSUCO and CSS was found to be approximately 2870 ml/m2 and 1830 ml/m2, respectively, whereas, on the second day, it was about 2680 ml/m2 and 1750 ml/m2. The productivity of SSUCO increased by 56.83 % and 53.14 % on day 1 and day 2, respectively. The thermal efficiency of SSUCO on day 1 and day 2 was found to be 45.52 % and 41.67 %, respectively, whereas, for CSS, it was 29.03 % and 27.21 %. Economic analysis showed that the cost per litre of yield and payback period for SSUCO was reduced by 40.54 % compared to CSS. Moreover, the environmental analysis revealed that the carbon credit gained by SSUCO was 64.2 % higher than that of CSS. The results indicate that CTESS is a highly promising technique for seawater desalination in solar stills. It provides notable advantages such as increased productivity, enhanced thermal efficiency, and significant economic and environmental benefits.

Role of nanomaterials on solar desalination systems: A review

The use of nanotechnology in various fields has garnered significant attention in recent years. One area where nanotechnology could prove particularly beneficial is in improvement of cheap and effective desalination units, which can help communities access freshwater in areas that are far away or economically disadvantaged. Desalination is the procedure that routines a significant amount of energy and accounts for a large portion of the costs associated with running a desalination plant. Additionally, the majority of the power used in desalination comes from traditional fossil-fuel-fired power plants, which contribute to greenhouse gas emissions and pose a threat to the ecosystem. Nanofluid technology has helped in improving the efficiency of solar distillation units, which provide a cheap and reliable means of producing fresh water. Recent studies have explored the use of nanotechnology in desalination, particularly in the role of renewable energy in distillation and brine treatment. One promising development is the use of nanofluid and adjusting the volume fraction of nanoparticles, which has been shown to increase the daily water output of solar distillation units. However, there are still challenges that need to be addressed, such as reducing the energy consumption and cost associated with desalination. Continued research in this area is needed to overcome existing challenges and further improve the efficiency and cost-effectiveness of desalination units.

Thermodynamic analysis of solar assisted steam distillation system for peppermint oil extraction

AbstractScheffler reflector (10 m2) integrated peppermint oil (PO) extraction distillation system is developed. Optical loss in reflector and thermal loss in solar still, steam line, and condenser are determined. A solar distillation system of peppermint plants is also subjected to thermal energetic and exergetic study. Exergy and optical efficiencies are 27.58% and 52.25%, respectively, with an average irradiance of 970.5 W/m2 and 6 kg of peppermint for 4 h. Thermal efficiency of solar still, steam line, and condenser are 95.90%, 95.68%, and 87.96%, respectively. Efficiency of system and oil yield per unit of energy consumed is 41.98% and 6.24 ml/kWh, respectively, without insulating steam line. System's efficiency is 46.36%, with an improvement of 2.67% in energy gain by insulating the steam line. Thermodynamic analysis of developed solar steam distillation system (SSDS) for PO extraction will help in finding out energy saving potential at various parts of distillation unit and in improving the performance of distillation unit. This research would provide energy conservation opportunities in various parts of PO extraction SSDS. Exergy analysis and detailed investigation of condenser and steam line are also performed. As a result, incorporating solar energy into PO extraction technology improves opportunities for the source of income in rural areas and increases both income and level of food security for farmers.Practical applicationsThis research would provide energy conservation opportunities in various parts of peppermint oil (PO) extraction solar steam distillation system. Exergy analysis and detailed investigation of condenser and steam line are also performed. As a result, incorporating solar energy into PO extraction technology improves opportunities for the source of income in rural areas and increases both income and level of food security for farmers.Novelty StatementMentioned literature includes thermodynamic analysis of oil extraction system available for crops such as rosemary leaves, basil leaves, etc. Thermodynamic analysis of such a system is limited to these crops and applied to other crops like peppermint, eucalyptus, lavender, etc. As these crops possess different chemical properties and have large potential in essential oil market, a comprehensive thermal analysis is needed to identify various thermodynamic parameters to extract peppermint oil (PO) using solar‐assisted steam distillation system. Present work aims to identify energy and power loss due to convection and radiation at different parts of a solar distillation unit. Exergy analysis and detailed investigation of condenser and steam line are also performed. This research would provide energy conservation opportunities in PO extraction solar steam distillation system. Furthermore, the outcomes of present study have been compared with previously published studies.

Solar powered hybrid desalination system using a novel evaporative humidification tower: Experimental investigation

Experimental investigation of a hybrid-solar desalination system consisting of a humidification–dehumidification unit and a solar distiller unit. At El Mahalah city- Egypt in climatic conditions, experimental work was performed under real thermal conditions in September 2021. A new design of helical humidifier and multi-section solar distiller has been tested. There is good agreement between the predicted and measured changes in water production and performance parameters. According to testing and operating parameters, the system's highest productivity was 6.7 kg/m 2 per day at a production cost of 10.4 $/m 3 . System performance was tested and represented by system efficiency, humidifier efficiency, and gain output ratio (GOR). The system efficiency, humidifier efficiency, maximum gain output ratio, and exergy efficiency reached 95%, 98%, 1.65, and 7.2%, respectively. The proposed hybrid desalination system gives an adequate operational compatibility between the HDH method and solar energy. • An experimental study for a solar hybrid desalination system has been conducted. • The highest productivity of the proposed system was 6.7 kg/m 2 per day. • The overall system efficiency reached 95% with an average water cost of 10.4 $/m 3 . • Exergy efficiency and maximum GOR reached 7.2% and 1.61, respectively. • A novel humidifier design was demonstrated with an efficiency reached 98%.

Evaluating the Performance of a Solar Distillation Technology in the Desalination of Brackish Waters

Desalination is set to become a major source of drinking water in several Middle Eastern countries over the coming decades. Solar distillation is a simple power-independent method of water desalination, which can be carried out in active or passive modes. This study is among the first attempts to investigate the possibility of desalinating brackish groundwater resources under the threat of saltwater intrusion in the southern areas of Razavi Khorasan province in Iran. For this purpose, a pilot solar distillation unit was constructed to analyze the effects of the unit orientation, depth of the water pool, atmospheric conditions, input salinity, and flow continuity on the solar distillation performance. The results showed that the unit exhibited the highest efficiency when it had a 3 cm deep water pool. It was oriented facing southward while operating a continuous flow for at least 3 days under sunny weather conditions. It was found that among the studied parameters, the unit orientation and pool depth had the greatest impact on the water production performance for this type of water desalination system. Conversely, the water production efficiency was not very sensitive to the input salinity level. Overall, the solar distillation technology was able to reduce the salinity by 99.7% and the hardness by 94.7%.

Development of candle soot dispersed phase change material for improving water generation potential of tubular solar distillation unit

Solar still is an economical device for purify brackish water, however its yield is low. Therefore, present work aims to increase the water output of tubular solar still (TSS) by introducing closed mild steel tubes filled with paraffin wax (as phase change material, PCM) and candle soot derived carbon nanoparticles (CSNP, 0.3 wt%) as dispersant for the first time. Experiments were conducted with three TSS – one with conventional TSS without any PCM, and the other two with only PCM and 0.3 wt % CSNP-PCM to augment the water production. There was an increase in thermal conductivity of 40.59% with 0.3 wt % CSNP over the base PCM. TGA analysis showed excellent thermal durability of 0.3 wt % CSNP-PCM and final degradation temperature was 314.26 °C. In addition, the dispersion of CSNP in PCM also altered the phase change temperatures with meager deviation from base case. The thermal performance analysis of TSS show that full day cumulative fresh water generation by conventional TSS was 3.04 kg/m 2 , whereas utilizing the PCM and 0.3% CSNP-PCM in tube inside TSS augmented the water generation by 42.4% and 87.82% respectively, than the baseline case. In addition, the modified TSS with PCM and 0.3 wt % CSNP-PCM exhibited higher energy efficiency of 59.26% and 109.94% respectively, than the base line case. The generated fresh water cost was only 0.014 $/kg for TSS with 0.3% CSNP-PCM. It is concluded that conductive CSNP doped PCM with excellent thermal performance significantly enhanced the water output of the SS and could be widely applied in other design of still for better thermal performance. • A new class of nano-enhanced PCM is prepared by functionalized candle soot particle. • TC of base PCM improved by 40.59% using 0.3 wt% CSNP. • TSS with base PCM improved water yield by 42.4% than baseline case. • TSS with CSNP-PCM improved water yield by 87.82% than baseline case. • Freshwater cost/kg using CSNP-PCM based still was 0.014 $.

Synergetic effect of absorber and condenser nano-coating on evaporation and thermal performance of solar distillation unit for clean water production

Two design modifications to increase the evaporation/condensation and freshwater yield of conventional solar stills (CSS) are presented – absorber coating with black paint (BP) in which 10 wt % reduced graphene oxide (rGO) was dispersed, and use of a nano-silicon-coated glass cover alongside the rGO coated absorber. Water contact angle analysis revealed that the hydrophilic glass/condenser hindered water droplet movement, whereas the hydrophobic silicon-coated glass enabled significantly faster water droplet movement. The rGO-coated absorber SS, with 99.2% solar absorptivity, improved the average water temperature by 11% leading to an augmented full-day freshwater yield of 3031 mL (versus 2160 mL for the CSS). The synergistic effect of the nano-silicon-coated glass and rGO-coated absorber further enhanced the full-day freshwater yield to 3410 mL. Energy/exergy analysis demonstrated enhanced efficiencies of the combined condenser and absorber coated SS of 37% (energy) and 112% (exergy), compared to the CSS. Non-linear characteristic equations described the instantaneous gain in energy efficiency of the combined absorber and condenser coated SS. Absorber/basin exhibited the highest rate of irreversibility in all three SS. The cost of water was 0.01 $/L for the dual-modified still. Water physicochemical quality analysis before and after desalination revealed that the purified water was suitable for drinking. • A solar still was fabricated with absorber and condenser coating for improved yield. • RGO coating improved the absorber average temperature by 10.9% compared to CSS. • Glass coated with nano-silicon altered condensation behavior to drop-wise from film-wise. • Modified SS showed augmentation in water yield compared to conventional SS. • Brackish water was converted into distilled water this is suitable for drinking.

Parametric investigation of a small scale seawater desalination unit fabricated by integrating evacuated tube collector basin and air-cooled condenser

Provision of potable water from brackish or saline feed water is a challenge in households of remote off-grid islands and coastal areas. An effort to study a small-scale desalination system comprising an evacuated tube collector (ETC) basin and an air-cooled condenser with the ultimate goal to produce fresh water in a decentralised manner has been carried out in this work. Experiments were performed on a solar distillation unit comprising a coupled 1 m2 ETC basin and 0.46 m2 air-cooled condenser in climate conditions of Bhavnagar, Gujarat, India. A maximum of 5.47 kg/day potable water of 50 ppm was obtained from seawater as feed, the average efficiency being 18.48% of the test setup. The volume of feed water charged in the basin played a vital role in the productivity, with the maximum distillate being attainable at 90% occupied volume.

Energy Analysis of Passive Solar Distillation Unit

The energy analysis of a passive solar distillation unit was the focus of this study. A 40-liter solar distillation plant was constructed and adjusted for the intended output of 5 liters of distilled water. The developed unit's performance was monitored from 8 a.m. to 5 p.m. Even so, the solar produced 4.5 liters of fresh water per m2 each day. According to the solar still's updraft assessment, the maximum daily energy efficiency was found to be 38.27 percent.

Economic Evaluation of Passive Solar Distillation System

A economic analysis of passive solar distillation unit is presented in the paper. Initial cost and maintenance costs, life of the system and estimates the cost of unit mass of distilled water were used to evaluate net present worth (NPW), benefit-cost ratio, payback period (PP) and internal rate of return (IRR) of solar distillation unit. Net Present Worth (NPW), Benefit-cost ratio, Payback Period (PP) and Internal Rate of Return (IRR) was calculated and found to be Rs. 26945.72, 1.5632, 1.538 year and 50 per cent respectively. This study found solar energy is one of the most attractive resources of energy to generate distilled water.

Comprehensive analysis of design software application in solar distillation units

The use of solar stills in rural regions are becoming increasingly popular as it is an economical solution for drinking water from saline water sources. Many researchers have worked for the improvement of conventional solar still to enhance productivity. Costly and time-consuming processes of operation in solar stills encourage many scholars to analyze mathematical simulation. This paper presents comprehensive reviews of the application of different design software to solar still systems. Design software is essential for developing and analyzing the mathematical models and predicting the most suitable performance parameters for the enhanced production rate of distilled water for still systems. Numerical modeling of solar still systems is necessary to analyze and investigate air movement, temperature variation for knowing water temperature, and air temperature through software like CFD, MATLAB, FORTRAN, TRYNSYS AutoCAD. The simulation technique's application using CFD is made with TRNSYS, FLUENT, ANSYS, FORTRAN and MATLAB which are useful tools to develop such mathematical models for the prediction of flow parameters. Engineering Equation Solver (EES) package and COMSOL Multiphysics solve the differential energy balance equation. All newly developed software employed for the utility of still solar systems is discussed. This article provides a comprehensive overview of the various software tools used in solar still to help researchers, scientists, and academicians.

Improving Performance of Hemispherical Solar Distillation Unit Using Paraffin Wax Encapsulated in Waste Aluminium-Cans

Improving Performance of Hemispherical Solar Distillation Unit Using Paraffin Wax Encapsulated in Waste Aluminium-Cans

Study of the energetic, exergetic, and thermal balances of a solar distillation unit in comparison with a conventional system during the distillation of rosemary leaves

The solar energy produced by Scheffler parabola (10 m2) is not fully exploited by the solar distillation system of aromatic and medicinal plants. In this work, the optical losses in the primary and secondary reflectors, and the thermal losses at each part of this system (solar still, steam line, condenser) were determined. A thermal energetic and exergetic analysis were also performed for a solar distillation system of rosemary leaves. For average intensity radiation of 849.1W/m2 and 6 Kg of rosemary leaves during 4 h of distillation, exergy and optical efficiencies of the system achieved up to 26.62% and 50.97%, respectively. The thermal efficiency of the solar still, steam line, and condenser is about 94.80%, 94.30%, and 87.76%, respectively. The essential oil yield per unit of consumed energy and the total efficiency of the solar distillation system, taking into account the heat losses in the solar still, steam line, and condenser, as well as the optical losses in the two reflectors, is 6.18 mL/ kWh and 40.00%, respectively. The efficiency can be as high as 42.42 % if the steam line is insulated. Moreover, the comparison between the solar steam distillation and conventional steam distillation shows that solar distillation is much more efficient since it gives better results and especially it avoids the emission of 12.10 kg of CO2 during extraction.

Exergoeconomic, environmental, economic, and energy-matrices (4E) analysis of three solar distillation systems equipped with condenser and different heaters

The water scarcity in the world in the near future become to a global challenge. The main aim of present study was to elucidate the performance of the three identical solar distillation units with different configurations under climatic conditions of the city of Tehran. All systems were equipped with different heating source that are thermoelectric heating modules (TEH), copper heater (CH), and solar water heater (SWH) while all system assisted with an active external condenser. Performance of all systems is scrutinized from different thermodynamic, thermoeconomic, environmental, and energy-matrices viewpoints. Findings revealed that the highest daily and annual productivity obtained by the system with CH. Economic analysis on the basis of uniform annual cost (UAC) revealed that the system with SWH has the lowest cost per liter (CPL) rather than other system while the highest CPL was for the case of TEH. Furthermore, it was concluded that the system with TEH obtain the most promising results in terms of exergoeconomic, enviroeconomic, and energy payback time (EPBT) because of the highest daily and annual energy and exergy output. Eventually, the environmental analysis indicated that the solar still with CH with 6342, 48.169, 18.46 kg emission of CO2, SO2. And NO have the best results rather than other systems

Effects of Brine Feed Rate and Number of Stages on Water Yield of Vertical Multi Effects Diffusion Solar Distillation Unit: Experimental Study

Effects of Brine Feed Rate and Number of Stages on Water Yield of Vertical Multi Effects Diffusion Solar Distillation Unit: Experimental Study

Performance analysis ofNidentical PVT-CPC collectors with an active single slope solar distiller and helically coiled heat exchanger using CuO nanoparticles

AbstractThis paper presents performance analyses based on temperatures, thermal energy (overall), thermal exergy (overall), electrical exergy, and yield of the systems that have been investigated. In the present study, an analytical expression of N identical partly covered photovoltaic compound parabolic concentrator collectors connected in series (N-PVT-CPC-SS-HE) with an active single slope solar distiller unit and helically coiled heat exchanger has been found. The performance analyses of the proposed system have been executed for 0.25% concentration of CuO nanoparticles for collectors (N = 4), and fluid-flow rate 0.02 kg/s in 280 kg mass of basin fluid. The system's performance is compared with a previous system of N identical partly covered photovoltaic flat plate collectors connected in series (N-PVT-FPC-DS-HE) with an active double slope solar distiller unit and helically coiled heat exchanger. The thermal energy is 112,109.1 kWh, thermal exergy 312.07 kWh, and yield 3,615.05 kg annually. It is found that daily enhancement in thermal energy of the proposed system with CuO nanoparticles compared with the previous system with various nanofluids CuO, Al2O3, TiO2, and water is found to be 16.75%, 51.13%, 61.82%, and 80.67% more significant correspondingly. The enhancement in yield of the proposed system is obtained for CuO nanoparticles greater than the previous system with CuO by 11.19%, Al2O3 17.2%, TiO2 26.25%, and water 32.17%. The electrical exergy is almost the same as the previous system.