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Solar pond is one of the latest technologies that have been used to produce fresh water in different countries. The studied solar pond consists of a metal floor and glass walls. In this research, a mathematical model is presented with the aim of estimating salt deposition. The results show that proposed model has high accuracy. Results show that sum of square error and relative error of proposed equation are equal to 3.048E−14 and 0.11214, respectively. In addition, the p-value and square error of proposed model have been validated. Results show that p-value of temperature and shear stress has a significant contribution in salt deposition. This research shows that R-Squared of proposed model is equal to 0.9359. This value indicates good validity of the proposed model. [ABSTRACT FROM AUTHOR]

The bioconvective flows are truly connected to real-life and engineering development. So, the models of biomicrosystems and biocells are considered for the technical analysis in this paper. Our intention for the current analysis was to theoretically examine electrical conduction flow into mass and heat transfer by an extensive gyrotactic microorganism into an inclined magnetic field toward a vertical stretching sheet with nonlinear solar radiation with different solar thermal appliances. The effect on velocity slip and Joule heating was again studied in detail. This classical problem on Navier Stokes equations to the current imitation was decreased to ordinary differential equations by applying the comparison method. The numerical solutions were changed by boundary value problem (BVP) to clarify the subject into finite difference numerical scheme by applying MATLAB. The important results show that the density of motile microorganisms reduces to the bioconvection Lewis number and Peclet number, although reverse performance was noticed for the bioconvection Rayleigh number. Further, solar radiation fosters heat transport. In this paper, complete analysis is provided for potential functions of solar thermoelectric cells, solar ponds, solar thermal power fabrication, etc. [ABSTRACT FROM AUTHOR]

The rising global energy demand necessitates innovative solutions for harnessing renewable energy sources. Solar ponds have received attention as they present a viable means to address this challenge by absorbing and storing solar radiation. This article provides a comprehensive review of solar pond technology, including its principles, applications, heat extraction mechanisms, and approaches to optimize performance, with special attention to the salt-gradient solar pond. Additionally, the article identifies challenges that currently hinder the large-scale adoption of solar pond technology and offers recommendations for future research. By providing a detailed analysis of the current trends and future research directions, this paper seeks to contribute to the ongoing efforts to improve these systems, exploring various approaches to increase their efficiency and make them more economical and environmentally sustainable. [ABSTRACT FROM AUTHOR]

Electrogen is a microbial group that plays an important role as anodic biocatalyst of microbial fuel cells (MFCs), one of the most extensively studied microbial-based technologies for bioelectricity generation. The aims of this research were to isolate potential electrogenic bacteria from aquaculture pond sediments and conduct a thorough evaluation on the MFCs' electricity production and efficiency parameters. A total of 18 electrogenic bacteria having various electrochemical abilities was successfully isolated using thioglycollate solid media enriched with Fe3+. Five isolates (namely KCf1, KCf2, KCf4, KCf10, and KCf14) were non-pathogenic electrogens and able to produce relatively stable and high open-circuit voltage values (690–810 mV) on glucose-fed MFCs. Further evaluations on electricity production in close-circuit mode (fixed resistor technique, polarization tests, and analysis of power overshoot phenomenon) and efficiency parameters (Coulombic and energy efficiencies) showed that KCf2, molecular identified as Bacillus altitudinis AC11.2, was the most potential MFC biocatalyst among all isolates. It produced an MPP value of 67.11 mW m−2, current density of 333.03 mA m−2, and Coulombic and energy efficiency of 53.86% and 63.27%, respectively. Efforts to increase the MFC's electrical output have been done by assembling four reactors in series and parallel circuits, obtaining the maximum total voltage of 1.6–2.0 V (for series configuration). This potential output was higher than a portable zinc–carbon battery (1.5 V) and a Ni–Cd battery (1.2 V). However, the voltage reversal suffered in series circuits was another challenge in the development of MFCs for bioelectricity production, since the existence of this phenomenon due to biological factors (microbial metabolism dynamics) are not easy to be controlled. [ABSTRACT FROM AUTHOR]

The cheapest and pollution-free method of producing drinkable water is solar distillation utilizing solar stills. However, the solar stills operate at lower-than-optimal efficiency, presenting significant room for improvement. Researchers have identified various techniques, modifications, and improvements to enhance efficiency in solar distillation. Notably, a solar pond is integrated with the solar still to boost performance, with the solar pond dramatically enhancing solar efficiency. In this research, four factors were identified as significantly influencing the performance of the solar stills: the concentration of sodium chloride (NaCl) in the solar pond, mini solar pond zones connected to the solar still, and the angles of internal and external reflecting mirrors. Three levels for each parameter were chosen for our study. The Taguchi method was utilized to identify the optimum level of these four parameters that maximizes performance. The best combination for maximizing efficiency was identified as connecting the solar still to the lower converting zone of the mini solar pond, using water containing 4 kg of NaCl, setting the internal reflecting mirror at 0°, and fitting the external reflecting mirror above the solar pond at 140°. This combination achieved a daily efficiency increase to 57.14%. Theoretical values were compared with experimental outcomes, showing that the solar still operated most efficiently between 12:00 and 14:00 h. The findings suggest not only immediate applications for improving solar still designs but also a pathway for future research into cost-effective desalination processes. [ABSTRACT FROM AUTHOR]

Design of economical and effective solar ponds which are useful thermal energy storage devices, remains a huge challenge. The present work aims at investigating the thermal performance of low cost mini salt gradient solar pond. The portable pond was fabricated as a rectangular configuration having a volume of 0.5m³. Polystyrene and high density polyethylene sheets were employed for insulating the walls. The top of the pond was covered with a slender glass so that the dust accumulation could be prevented without affecting the absorption of solar radiation. Sodium chloride salt was used as the medium and the three salt gradient regions namely lower convective, non-convective, and upper convective regions were established through injection filling technique. The temperature and salt gradient data were observed experimentally for a period of 20 days at Coimbatore, India. The pond could absorb significant amount of available radiation (around 65%) and the maximum temperature of the pond was observed to be 49 °C. Frequent washing of the water surface is necessary to maintain stable salt gradient. Nevertheless, portable pond fabricated with low cost materials exhibited good potential of storing solar energy for solar thermal applications. [ABSTRACT FROM AUTHOR]

Nowadays, nanofluids are considered as excellent working fluids with good thermophysical properties for augmenting the heat transfer in solar systems. Consisting of single-phase nanopowder, metal oxide-based nanofluids exhibit either a good thermal network or good physicochemical properties. Allotropes of carbon (e.g., carbon nanotubes; CNTs and graphene) have their own set of distinct structural and thermal properties to enhance the thermophysical properties of base fluids (e.g., water, ethylene glycol, etc.). For working fluids, researchers tried to optimize the preparation methodology in which a two-step method has been preferred due to the synergistic involvement of solid (i.e., particulate) and liquid (i.e., base fluid) phase. Also, several research groups have discussed the thermal behavior of different nanofluids with the help of correlations. A combination of MgO and CNTs has also been studied thoroughly to distinguish the effect of temperature and concentration of solid phase on the thermal conductivity of nanofluid. Further, CNT/graphene-based nanofluids serve a critical role in improving the thermal performance of solar collectors, solar stills, solar ponds, and solar cookers. It can also be utilized to reduce the surface temperature of solar cells in photo voltaic thermal (PV/T) systems which in turn increases the electrical efficiency of these systems. The present work illustrates a detailed review on the CNT/graphene-based nanofluids and their structural features for different solar energy applications. [ABSTRACT FROM AUTHOR]

This research focuses on the influence of water turbidity on the thermal efficiency of solar ponds, innovative devices designed for the concurrent collection and storage of solar energy utilizing salinity gradients. A three-dimensional simulation approach is employed to analyze solar ponds under varying turbidity conditions, namely clear, slightly turbid, and very turbid water. The findings reveal that increased turbidity levels lead to reduced solar radiation penetration, consequently decreasing the temperature in the pond's bottom storage zone. Notably, the presence of a temperature profile across horizontal planes in solar ponds, as identified in this study, challenges the adequacy of conventional onedimensional models in explaining certain phenomena. This insight casts doubt on the widely accepted concept of distinct upper and lower convective zones within solar ponds, suggesting a need to re-evaluate this hypothesis. Moreover, the ground beneath solar ponds is posited as a potential secondary heat storage zone. The study proposes the strategic placement of heat exchangers in the central circular ground plane, just beneath the bottom of the pond. This positioning is recommended to optimize heat extraction efficiency while circumventing the placement of exchangers in the corrosive Lower Convective Zone (LCZ), thereby reducing maintenance costs. The findings underscore the necessity of considering three-dimensional aspects in solar pond analyses for a more comprehensive understanding of their thermal behavior. [ABSTRACT FROM AUTHOR]

A solar pond is an environment‐friendly system for storing thermal energy. Solar ponds can balance the energy supply and demand when incorporated with PCM. Solar thermal energy can be stored inside the solar pond and used for solar drying, desalination, and power production. The present study reports the heat change in the solar pond with or without PCM and nanoparticles. From the literature, it was found that handling phase change material is difficult, and added nanomaterials are used to settle with time, which reduces the efficacy of the system. The novelty of present study is to examine the performance of nanoparticle‐embedded paraffin the sensible energy storage in the solar pond. The experiment has been performed, and results have been investigated/compared for four cases, namely, (i) solar pond, (ii) solar pond with heat storage (ie, paraffin wax [PW]), (iii) solar pond with aluminum oxide (Al2O3) mixed PW, and (iv) solar pond with copper oxide (CuO) mixed PW. The results show that with the addition of 1% and 2%, Al2O3 and CuO in PW, the thermal conductivity is increased by 2.94%, 5.92%, 2.99%, and 6.01%, respectively, compared to basic paraffin wax. It can be observed from the results that with the inclusion of CuO in paraffin wax solar pond temperature was high during non‐sunshine hours compared to other solar ponds. The results also show that sensible energy without heat storage material is negligible during non‐sunshine hours compared to heat storage and nanoparticle‐embedded heat storage solar ponds. Incorporating CuO in paraffin wax showed significant potential to store heat energy. [ABSTRACT FROM AUTHOR]

The realm of sustainable energy systems has seen the salt gradient solar pond (SGSP) emerge as an eco-friendly solution for thermal energy storage. This research explores the use of an East-West (EW) reflector and coal cinder additive (CC) to enhance the energy efficiency of the inner zones of a salt gradient trapezoidal solar pond (SGTSP). In this work, SGTSP with EW and CC systems were designed, fabricated, and analyzed based on an energy point of view and compared with standard SGTSP systems. It also provides a shading area analysis based on the slant angle of the SGSP system, offering valuable insights into the system's performance for low-grade heat source thermal applications. The study found that the EW reflector significantly increased the average solar intensity by 33.2%. The addition of coal cinder additive raised the average temperature of the lower convection zone by 24.1%. The SGTSP with EW reflector and coal cinder (SGTSP-EWR&CC) reached a maximum average temperature of 83.85°C, with a 42% higher energy efficiency in the lower convection zone compared to the conventional SGTSP (SGTSP-C). Further, the SGTSP's potential for thermal energy storage and providing practical strategies for enhancing its energy efficiency is showcased. [ABSTRACT FROM AUTHOR]

This work researches producing electricity and hydrogen production performance of a solar pond integrated with parabolic trough solar collectors. The system consists of parabolic trough solar collectors and a solar pond with a surface area of 100 m2 and 200 m2, an organic Rankine cycle operating with n-butane for electricity production, a proton exchange membrane for generating hydrogen, and a mushroom production unit. The system was operated for five mass flow rates m ˙ 1 = 0.350 k g / s , m ˙ 2 = 0.355 k g / s , m ˙ 3 = 0.360 k g / s , m ˙ 4 = 0.365 k g / s , m ˙ 5 = 0.370 k g / s. To improve the overall system performance, n-butane is selected as the operating fluid in the organic Rankine cycle and the waste heat of the organic Rankine cycle was used to heat the mushroom production unit. In addition, the preheating water produced by the solar pond was transferred to the parabolic trough solar collectors via a pump. The temperature of this preheated water was quickly raised by the parabolic trough solar collectors and pumped to the organic Rankine cycle. Thus, the organic Rankine cycle's electricity generation performance was also tried to be increased. With efficient electricity produced, the hydrogen production performance of the proton exchange membrane was improved. Thus, the amount of hot water, electricity, and hydrogen produced in the integrated system, the organic Rankine cycle, the parabolic trough solar collectors, and the energy and exergy efficiencies of the entire system were determined daily for five different masses. As a result, for five different masses, it was found in which mass the system performed the best. The whole system was analyzed with the engineering equation solver program. It was found that the system performs best at noon for all mass flow rates. It was also found that the performance of the system, the amount of electricity, and the hydrogen it produced increased as the amount of mass decreased. It was seen that hydrogen can be produced as 534.32 g and 519.06 g for m ˙ 1 and m ˙ 5 in a day, respectively. The energetic and exergetic efficiencies of the system were also found to be a maximum of 13.77% and 5.79% for m ˙ 1. • Hydrogen production of a different solar integrated system. • Thermodynamic performances of the parts of the system and overall system. • The comparison of the hydrogen production for five different mass flow rates. • The effect of thermal energy on hydrogen production in a day. [ABSTRACT FROM AUTHOR]

The increasing demand for renewable and environmentally friendly energy sources is a top priority for many countries around the world. It is obvious that renewable solar energy will help to meet most of the energy demand in the coming years. A solar pond is a huge Salt artificial Lake that serves as a solar energy collection system. However, site selection is a critical factor that affects the effectiveness and lifetime of a solar pond. Here, we present an innovative methodology for site selection based on three environmental factors, including direct solar irradiance (DNI), temperature, and wind speed. Our approach uses Python programming and clustering analysis with several libraries, including Pandas, Geopandas, Rasterio, Osgeo, and Sklearn, to analyse and process data collected over a 30-year period from NASA power. This method was applied to the geographic boundaries of Egypt, but the methods can be applied to any spatial context if the same dataset is available. The results show that Egypt has a potential land area of 500 km2 suitable for solar ponds construction along the border with Sudan throughout the year, including 2000 km2 in winter (between January and March), 800 km2 in spring (between April and June), 900 km2 in summer (between July and September), and the largest area of 3700 km2 (between October and December), most of which is located in the south of the Eastern Desert and around the Nile River. Notably, the northwestern region, close to the Mediterranean Sea on the border with Libya, exhibits suitability for solar pond development, with consistent performance throughout the year. Our results provide an efficient way for GIS and data processing and could be useful for implementing new software to find the best location for solar ponds development. This could be beneficial for those interested in investing in renewable energy and using solar ponds as an efficient water treatment plant. [ABSTRACT FROM AUTHOR]

This study is an endeavour to introduce a novel approach to enhance the performance of solar collectors. The sun emits sufficient power of solar radiation to meet the demand of energy. Harvesting the renewable solar energy needs advanced technologies and requirements. Solar ponds including salinity gradient solar ponds (SGSPs) are common solar collectors. These ponds are one of the solar energy applications used for many industrial and domestic purposes. However, challenges of the conventional SGSPs such as evaporation, salt diffusion, temperature discrepancy, and layer mixing profoundly and significantly affected their expansion globally. A novel experimental solar collector configuration to overcome the challenges of the conventional solar ponds (solar collectors) is investigated, there is no water body and no salinity gradient to build; it is entirely a collector with no water body. The experimental unit was constructed in an arid area. It is basically a cylindrical tank with a total depth of 1.4 m with three zones or layers to store heat namely, paraffin wax layer (10 cm thickness). The paraffin layer was covered with a layer of coal with a thickness of 30 cm. On the top of coal layer, an air gap with a thickness of 80 cm was left. A clear plastic cover with a thickness of 0.2 cm was utilized to cover the constructed layers and making the air gap. The experimental unit was monitored, and temperature measurements were collected for the period of 17/7/2021-30/9/2021. The results demonstrated that temperature of the paraffin wax layer reached more than 48 °C in a short period and with a small day and night discrepancy (1 °C). Temperature of the paraffin layer remained constant around 43 °C even in night-time during the period of the study. Furthermore, the results showed that temperatures of coal layer and air gap reached the maximum at the daytime of 53 °C and 71 °C respectively with a clear discrepancy between day and night. The results of the present study are encouraging for more investigations in this new direction of solar collectors. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the transient behavior of a salinity gradient solar pond (SGSP) under Mediterranean climate. For this purpose, a 2D numerical model is developed in which the absorption of solar radiation by different layers of saline water, the wind effect at the SGSP free surface, the heat losses from the SGSP free surface, and the development of the double-diffusive convection in the lower and upper convective zones are considered. The governing equations of continuity, momentum, thermal energy, and diffusion are solved using the finite volume method with SIMPLE algorithm. The validity of the numerical model developed in fortran 95 programing language is achieved through the comparisons of the results computed with the available numerical and experimental results obtained by literature studies. Results show that the developed numerical model can predict transient behavior of the SGSPs with a good accuracy. As an application of this model, the temperature, salt concentration, energy stored, and storage efficiency variations of a proposed SGSP are analyzed under Mediterranean climate. The results show that the lower convective zone (LCZ) temperature increases from 15 °C to around 95 °C whereas the temperature of the upper convective zone (UCZ) varies sinusoidally depending on that of the ambient air. Furthermore, the salt concentration of the LCZ decreases from 250 kg/m³ to around 248 kg/m³ while that of the UCZ increases from 50 kg/m³ to about 52 kg/m³. Additionally, the thermal energy stored is around 135 MJ with an efficiency of about 38%, which confirms the capacity of the SGSP to store thermal energy as sensible heat. [ABSTRACT FROM AUTHOR]

In this research, the efficiency of a solar distillation system as a passive technique in the process of water distillation from wastewater was investigated. The solar distillation process is proposed as a desalination process with zero discharge (ZD), in order to prevent salt water from entering to the sea and using salt water. In this study, three solar ponds with three different floors were used. Laboratory data show that the density of wastewater varies between 1.09 and 1.27 g/cm3 when using simple flooring. The amount of density changes when using floor covering made of nanozinc oxide is between 1.05 and 1.21 g/cm3. Laboratory data show that changes in density when using flooring made of nanoaluminum oxide are between 1 and 1.17 g/cm3. The laboratory results show that heat capacity of the wastewater decreases with increase in the depth of the effluent. Results show that flooring made of nanoaluminum oxide increases the rate of evaporation by about 17% and flooring made of zinc oxide by about 11%. [ABSTRACT FROM AUTHOR]

In this work, the effect of with and without phase change materials for long‐term heat storage of a salt gradient solar pond was investigated both experimentally and numerically. Some phase change materials, whose thermal values are close to the operating temperature of the solar pond were selected and examined from fatty acids (camphene, decanoic acid, and palmitic acids) and paraffin derivatives (paraffin wax, C20‐C33, and C16‐C28). A series of experimental studies were then performed with phase change temperature, latent heat and thermal stability, a differential scanning calorimetry, and a thermogravimetric analyzer for sheath, decanoic acid, and palmitic acid. The temperature and enthalpy curve of each phase change material was calculated by months and compared to the solar pond and the longest‐term heat storage was determined. Study shows that the maximum efficiency of the solar pond can be achieved with 24.58% Camphene in November and 22.57% Paraffin C20‐C33 in December. Thus, the camphene shows the best longest‐term heat storage performance thanks to its high melting temperature and density and latent fusion heat. It is one of the best suitable options to improve the heat storage performance of solar ponds. [ABSTRACT FROM AUTHOR]

Featured Application: The present paper evaluates 10 alternative shoreline pond electrode station designs using frames in a linear arrangement of electrodes for HVDC interconnections, against the typical design, according to CIGRE B4.61/2017 (parallel arrangement of electrode frames, with respect to the longitudinal axis of the breakwater), studying it from the point of view of electric field analysis (with emphasis on the near-field). During the design of a shoreline electrode station for High-Voltage Direct Current (HVDC) interconnections, the location of the electrodes plays a critical part, especially in the development of the near-electric field. The basic structure is their linear placement, in the form of successive frames, parallel to the longitudinal axis of the breakwater, as proposed by CIGRE and implemented in existing projects. However, this arrangement requires a considerable breakwater length, which may not be permissible, as in the case of Stachtoroi, one of the two electrode stations being built for the 1 GW, ±500 kV HVDC interconnection between Crete and mainland Greece. This troubled the preliminary study team of the electrode stations, which investigated other possible configurations. In this paper, configurations of linear placements of electrode frames are studied and compared at the preliminary study level in terms of electric field effects (especially the near-field), using an analytical simplified model and the superposition method, to determine the most appropriate arrangement of electrodes that will cover the respective requirements of CIGRE directives B4.61/2017. These arrangements are practically evaluated for two different electrode station locations at Korakia in Crete and at Stachtoroi in Aegina for the Crete–mainland-Greece interconnection, resulting in interesting alternative solutions. [ABSTRACT FROM AUTHOR]

We present models for convection in a mixture of viscous fluids when the layer is heated from below and simultaneously the pointwise volume concentration of one of the fluids is heavier below. This configuration produces a problem of competitive double diffusion since heating from below promotes instability, but the greater density of fluid below is stabilizing. The fluids are of linear viscous type which may contain Kelvin–Voigt terms, but density gradients due to the mixture appear strongly in the governing equations. The density gradients give rise to Korteweg stresses, but may also be described by theory due to Kazhikhov and Smagulov. The systems of equations which appear are thus highly nonlinear. The instability surface threshold is calculated and this is found to have a complex nonlinear shape, very different from the linear ones found in classical thermohaline convection in a Navier–Stokes fluid. It is shown that the Kazhikhov–Smagulov terms, Korteweg terms and Kelvin–Voigt term play a key role in acting as stabilizing agents but the associated effect is very nonlinear. Quantitative values of the instability surface are displayed showing the effect Korteweg terms, Kazhikhov–Smagulov terms, and the Kelvin Voigt term have. The nonlinear stability problem is addressed by means of a generalized energy theory deriving different results depending on which underlying theory is employed. [ABSTRACT FROM AUTHOR]

• Thermal-hydraulic performance of solar ponds having ST equipped with modified TTs. • Good agreement between numerical and experimental results (less than ± 11% deviations). • Overall performance index from 1.08 and 3.76 for the optimal m and T in. • Noticeable effects on flow features of working fluid by employing variable twist pitches. • Highest heat extraction with ST enhanced by TTs with LH arrangement of twist pitches. The thermal energy collected and stored by solar ponds is usually extracted by using some heat exchangers, where curved tubes form their core. The present study aims to appraise the performance of a serpentine tube under varied mass flow rates and inlet temperatures of the working fluid. Three different types of twisted tapes nominated as uniform twist pitches (U), low to high twist pitches (LH), and high to low twist pitches (HL) are employed to enhance the heat extraction rate. This article is the first report addressing the application of non-uniform twisted tapes as turbulators in a serpentine tube. In this regard, a solar pond simulator containing salt water is designed and fabricated. Numerical simulations are also carried out to display the transport phenomena inside the models. The numerical results are compared with the experimental data, and a close agreement is found. From the thermal point of view, the sequence of twisted tapes is LH > HL > U, while it follows the order of U > LH > HL according to the frictional loss. The findings demonstrate that depending on operating conditions, the heat extracted by the modified cases is 4 to 70% more than the base model. It is also found that employing non-uniform twisted tapes results in lower flow resistance compared to the uniform case. The pressure drop augmentations produced by U, LH, and HL TTs are 26.5%, 17.5%, and 10.4%. Further, the overall performance index is higher than unity for all the enhanced cases. The best case is the twisted tape having low to high twist pitches (LH) which has an average performance index from 2.03 to 2.71. [ABSTRACT FROM AUTHOR]

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A study has created a solar pond model. The pond's performance in terms of heat storage and electric power generation using TEG is analyzed using this model. The impact of various parameters, such as covering the pond's surface with plastic and using reflectors to focus on the intensity of solar radiation, will be investigated. A pyramidal pond with a base size of 0.64 square meters was used to validate the model. And it has a 6.25 square meter surface area. There's also a 1.35-meter depth. The walls are inclined at a 60-degree angle. TEG was also used to determine the pond's electrical capacity. The addition of a plastic cover and reflectors enhanced the efficiency of the pond's operation from 12.1% to 27.5%, according to the findings. At a lower layer temperature of 60 degrees Celsius, the electrical capacity reached 104 watts with a TEG operating efficiency of 8.9%. [ABSTRACT FROM AUTHOR]

There has been a practice of converting saltwater into potable water using solar stills for more than a century. Their production is only 2,000–5,000 mL/m² ·d, considering all the modifications. The process of production is expensive and inconvenient. The double basin solar stills are the only recommended solution to this problem. In this work, the performance of a double basin solar still with exterior reflectors, lower basin with flat plate collector (FPC) and mini solar pond has been examined and it was executed in Francis Xavier Engineering College, Tirunelveli, Tamil Nadu, India (latitude 11.9089° N, longitude 79.7589° E) with 09.00 to 19:00 h on a daily basis for a period of 20 d. Further, it has been examined whether the modifications have an impact on the effectiveness of double basin. Even in double basins, the 100 cm² × 100 cm² upper basins have a 5-step tray inside the lower basins for stability. There is a total of 25 compartments in each tray, having five portions each section. Materials, such as granite, for storing the heat is present in each unit. The yield of distilled water has been increased to 5,650 mL/m² ·d, when the external reflectors were installed. The yield has further increased to 6,249 mL/m2 ·d when the double basin solar still is connected to the FPC and small solar ponds. The overall yield due to the modifications has been increased by 127.5%. [ABSTRACT FROM AUTHOR]

A salinity gradient solar pond (SGSP) is capable of storing a significant quantity of heat for an extended period of time. It is a great option for providing hot water at a reduced energy cost. Additionally, SGSP is used in low-temperature industrial applications such as saltwater desalination, space heating, and power generation. Solar pond thermal performance is dependent on a variety of operational variables, including the soil conditions, the climate of the particular site, the thickness of the solar pond layers, the depth of the water table, and the salt content of the pond. As such, this study examines the thermal performance of a solar pond under a variety of operational conditions. The solar pond model is used to test the thermal performance by simulating two-dimensional heat and mass transport equations. The equations are solved using the finite difference technique utilizing MATLAB® scripts. Salt distributions and temperature profiles are computed for a variety of factors influencing SGSP's thermal performance. The main distinguishing variables influencing the thermal performance of SGSP are soil conditions, such as soil texture, types, the moisture level in soil, and water table depth. The final findings indicated that the fine sand dry soil performed better than the other soil types owing to its poor heat conductivity. The economic results indicated that the period of return (POR) of the intended system is around 2 years. The solar pond construction costs such as excavation, transportation, salt and lining, were considered based on the local prices. This modeled study extracted the greatest possible energy is 110W/m2, with the fine sand dry at 62.48°C lowest temperature. This study suggested that the climatic conditions of Lahore is better than climatic conditions of Islamabad. Additionally, deeper water tables are suggested for improved thermal performance of the pond. [ABSTRACT FROM AUTHOR]

Dunaliella salina (Chlorophyceae), Phormidium versicolor (Cyanophyceae), and Cylindrotheca closterium (Bacillariophyceae) were isolated from three ponds in the solar saltern of Sfax (Tunisia). Growth, pigment contents, and photosynthetic and antioxidant enzyme activities were measured under controlled conditions of three light levels (300, 500, and 1000 µmol photons m−2 s−1) and three NaCl concentrations (40, 80, and 140 g L−1). The highest salinity reduced the growth of D. salina and P. versicolor NCC466 and strongly inhibited that of C. closterium. According to ΦPSII values, the photosynthetic apparatus of P. versicolor was stimulated by increasing salinity, whereas that of D. salina and C. closterium was decreased by irradiance rise. The production of carotenoids in D. salina and P. versicolor was stimulated when salinity and irradiance increased, whereas it decreased in the diatom. Catalase (CAT), Superoxide dismutase (SOD), and Ascorbate peroxidase (APX) activities were only detected when the three species were cultivated under E1000. The antioxidant activity of carotenoids could compensate for the low antioxidant enzyme activity measured in D. salina. Salinity and irradiation levels interact with the physiology of three species that have mechanisms of more or less effective stress resistance, hence different resistance to environmental stresses according to the species. Under these stress-controlled conditions, P. versicolor and C. closterium strains could provide promising sources of extremolyte for several purposes. [ABSTRACT FROM AUTHOR]

In the present study, the influence of water thickness for the active solar still (solar still integrated to solar pond as an external source of heat addition) has been studied for an attempt to obtain the appropriate water depth. The accumulated and hourly distillate of solar still with float wicks in different proportions of covered area of 50%, 75%, and 100% and integrated to shallow solar pond have been investigated. With the use of float wicks alone, a reduction in basin water temperature of solar still has been noticed during daytime because of the restriction of solar radiation to reach the basin absorber. Therefore, to overcome this problem, an additional thermal energy from solar pond has been supplied to solar still through heat exchanger in continuous mode from 8 am to 8 pm. The maximum distillate output was obtained with 5 cm depth, which were 13.6%, 20.69%, and 29.87% greater over water depth of 4, 6, & 7 cm, respectively. An enhancement of 7.2%, 9.2%, 38.13%, and 23.33% have been obtained for the solar still with float wicks alone, solar still assisted with solar pond and having float wicks in proportion of 50%, 75%, and 100%, respectively, over conventional still. [ABSTRACT FROM AUTHOR]

Heat energy storage is pivotal in modern times. However, the technology to efficiently stored heat energy is still in the research stage. Heat energy storage is possible through phase change material, exothermic chemical reactions, and solar ponds. The latter uses a natural phenomenon that relies on solar Energy and convective heat transfer. Solar ponds can store more heat energy throughout the day than other processes and meet higher energy demands. The working principle of a typical solar pond can be adopted to develop a compact setup that can store sufficient heat energy to meet the heat energy demand of a small family. Salinity gradient solar ponds are used for heat storage to meet the demand of rural and urban communities in arid and semiarid zones around the globe. Often the solar ponds are constructed on the ground by storing a large volume of salt water. The performance of the solar pond is affected by the intensity of solar radiation. In this study, a compact solar pond is constructed using aluminum plates and a glass cover. Sea water was used to store solar radiation in this experiment. The experiment was carried out in South India during the winter season when the intensity of solar radiation was minimum. The study aims to determine the performance of the solar pond and its thermal properties under low sunshine. Heat storage mediums comprising paraffin wax and additives of nanoparticles of graphene and carbon nanotubes were used to enhance the heat storage capacity of the solar pond. It was found that compared to the simple salinity gradient solar pond, the heat storage medium with carbon nanotube nanoparticles increased the maximum temperature attained by 26.5%. The carbon nano tubes infused phase change material increased the heat transfer, heat transfer coefficient, and the heat stored in the saline water by 244%, 713%, and 83.3%, respectively. It is concluded that the carbon nano tubes and phase change material augmented the performance of the solar pond even while the intensity of solar radiation was low. [ABSTRACT FROM AUTHOR]

This work proposes the degradation of different contaminants of emerging concern (CECs) present in a secondary effluent from a municipal wastewater treatment plant in a solar electrochemical raceway pond reactor (SEC-RPR), applying the solar photo electro-Fenton (SPFE) process. Tap water and a secondary effluent were enriched with 100 µg L−1 of 7 CECs to study the degradation of these compounds by the SPEF process in a SEC-RPR. Among the results obtained, an elimination over 96% and 90% of 5 CECs (progesterone, estradiol, ibuprofen, diclofenac and estrone) was achieved, while sulfamethazine and carbamazepine were eliminated by 73, 37% and 80, 66% after 1 h of treatment, respectively. In turn, a secondary effluent that already achieved the minimum organic load standards established by Chilean regulations was treated in a SEC-RPR by applying different electrochemical advanced oxidation processes (EAOPs). However, regardless of the applied treatment (SPEF, electro-Fenton and electro-oxidation/H 2 O 2), it was possible to further reduce the organic content and even mineralize it. These experiments were performed at pH 3, with Na 2 SO 4 0.05 mM, Fe2+ 0.05 mM and applying a current density of 20 mA cm−2. The SPEF process implemented in a SEC-RPR is presented as an excellent alternative for the treatment of municipal wastewater, due to the large contact area between the effluent and UV radiation, in addition to the continuous and homogeneous generation of H 2 O 2 , which allows for the production of hydroxyl radicals in solution, favoring the degradation and mineralization of pollutants. [Display omitted] • Elimination of contaminants of emerging concern by solar photoelectron-Fenton process in a solar raceway pond reactor. • Identification and elimination of 29 CECs in secondary effluent. • A continuous and homogeneous electrogeneration of H 2 O 2 in the SEC-RPR allows the effective CECs degradation. • Short electrolysis time were applied for the CECs removal under real conditions. [ABSTRACT FROM AUTHOR]

Lebanon, currently engulfed in a severe economic crisis, grapples with substantial challenges in electricity provisioning due to systemic grid failures, foreign dependence, depleting resources, and the costly adoption of fossil fuels. These exigencies necessitate a shift towards innovative, renewable energy solutions, thereby positioning Salinity)Gradient Solar Ponds (SGSPs) – artificial reservoirs harnessing and storing solar energy – as a potentially effective response. This study proffers an instrumented engineering proposal advocating the implementation of SGSPs in Lebanon, detailing the operational management, control, and maintenance required for reliable heat production. By articulating the feasibility and benefits of SGSPs within the Lebanese context, the paper underscores their potential to alleviate existing energy constraints and foster a more sustainable, self-sufficient energy future for the nation. [ABSTRACT FROM AUTHOR]

Solar‐driven interfacial evaporation systems have been considered to achieve broad application prospects in the field of cogeneration of steam and electricity. However, the electricity generated is often independent of the photothermal system, hindering their integration. Compared with traditional materials such as metals and semiconductors, the application of biomass materials can solve the problems of high cost and environmental pollution in the expansion and relevance of interfacial evaporation technology. Herein, the solar evaporator composed of carbonized sphagnum palustre with cellulose fabric (CSPF) is fabricated for simultaneous steam production and power generation. Additionally, a device consisting of the CSPF and other accessories such as heating wires is designed to enhance steam production by self‐driven electrothermal heating. The self‐driven solar evaporator endows enhanced evaporation rates to 2.12 kg m−2 h−1 under electrothermal effect and the high electrical energy outputs of 520 mV. The solar evaporator has good salt tolerance and excellent cycle stability, maintaining a high evaporation rate in high‐salt solutions and after 24 cycles of testing. The outdoor evaporation tests reveal the encouraging performance of the steam and energy generators in real environment. Such superior performance of comprehensive device has great potential for integrated and sustainable application in cogeneration systems. [ABSTRACT FROM AUTHOR]

Solar ponds are characterized by high storage capacity and the ability to provide a stable and continuous power source. Careful selection of the extraction rate helps to maintain supply temperature in a range suitable for the operation of an absorption unit. This study proposed a system in which a solar pond is coupled with an absorption chiller to investigate the resulting advantages. The chiller is cooled by using water of the upper convective zone, which ensures that the limit of deterioration of its performance is not reached and eliminates the need for an expensive cooling system. The key parameters in terms of ambient temperature, solar radiation, pond specifications, and cooling and refrigeration temperatures are investigated to optimize the proposed system design. The prediction of the model showed good agreement with the experimental results. By choosing the appropriate place to implement the system, such as the Dead Sea area, which enjoys favorable climatic conditions, it was found that a pond with an area of 3000 m2 can produce a heat rate at a temperature of 80 °C that can drive a chiller with 126.3 kW cooling capacity, with overall COP of 0.183. Based on this study, it appears that this type of system is feasible and suitable for cooling production, especially in hot regions. [ABSTRACT FROM AUTHOR]

• A three-zone extraction system in solar ponds for desalination is proposed. • Temperature drop across exchanger surfaces is considered. • Simplified model is validated with theoretical results of literature. • Possible extraction mechanisms are compared quantitatively and qualitatively. • Influence of user defined parameters on distillate output is investigated. A solar pond from which thermal energy is extracted from its non-convective zone (NCZ), lower convective zone (LCZ) and the ground below is modelled in transient state. The novelty of the study lies in the fact that heat extraction in each of the three zones is considered to be realistic, taking into account temperature drop across the exchanger surfaces. The pertinent weather parameters are described by curve fitting as series of sinusoidal time functions. Using these expressions, implicit finite difference method is used to solve the five coupled partial differential equations involved in the analysis, and the scaled down model is validated with simpler models available in the literature. To quantify the practical utility of pond, the final outgoing water stream heated from the pond is fed to a large scale solar still to assess the usefulness in a desalination application. Annual distillate production of the still coupled to such a pond is calculated and its variation with various manually adjustable parameters is studied. A total of 9 such parameters have been investigated. It is observed that there are five pond parameters related to pond's operation that possess optimum values that maximize annual distillate production. These are: NCZ and LCZ thicknesses, NCZ and LCZ exchanger pipes' radii, and ground extraction mass flow rate. An increase in any of the remaining parameters: upper convective zone (UCZ) thickness, ground exchanger pipes' radius and NCZ , LCZ extraction mass flow rates generate a decrease in distillate produced. It is also revealed that extraction should be carried from how many zones depends on the application coupled to the pond, and in this case, where the application is a solar still, LCZ with ground extraction turns out to be the best choice. Further, the assumption of ideal NCZ and ground extraction used in the literature is seen to overestimate system output by nearly 46%. Therefore, this model is a generalized one and various other single or dual zone extraction models available so far become subsets of it. This generalized model presented here can serve to design such a triple zone extraction based solar pond system in a realistic and practical manner and help evaluate suitable values of user-controlled variables that yield maximum output of the application to which the pond supplies energy. [ABSTRACT FROM AUTHOR]

• The growth of solar energy usage and solar power generated in India is exponential. • Theoretical and experimental research efforts in India on solar ponds are elaborated. • The possible scopes of applications of solar ponds in India are detailed. • Problems faced by the solar pond researchers are discussed. • Future of solar pond research in India is illustrated. Solar pond is generally a shallow artificial pool of water in which considerable temperature can be established within its lower layers by suppression of convective transport. Generally, for prevention of convection, some suitable salt solution is used. In this paper, various aspects of solar pond, in terms of both simulation and experimental research advances, practical applications, economic features, challenges faced and future prospects, particularly with respect to Indian context have been reviewed. In general, the importance and the position of India at global level in terms of solar energy harvesting potential have been discussed. Apart from conventional uses of solar ponds in process heating and salt production, their applications in water distillation and thermoelectric power generation are also highlighted. Besides, stability aspect and its importance are revisited from simulations and experimental observations. Important identified areas requiring future research and development to recognize more technically feasible solar pond-based systems include organic Rankine cycle for electrical power production, crop drying, building cooling and air-conditioning based on absorption systems, thermoelectric cooling, and integration of solar ponds with other renewable energy resources. The present literature is proposed to offer guidelines in policy making aimed at addressing various societal requirements in a sustainable and affordable manner by utilizing available natural resources. [ABSTRACT FROM AUTHOR]

Solar crystallizer ponds are characterized by high population density with a relatively simple community structure in terms of species composition. The microbial community in the solar saltern of Santa Pola (Alicante, Spain), is largely dominated by the hyperhalophilic square archaeon Haloquadratum walsbyi. Here we studied metatranscriptomes retrieved from a crystallizer pond during the winter of 2012 and summer of 2014 and compared Hqr. walsbyi's transcription patterns with that of the cultured strain Hqr. walsbyi HBSQ001. Significant differences were found between natural and the cultured grown strain in the distribution of transcript levels per gene. This likely reflects the adaptation of the cultured strain to the relative homogeneous growth conditions while the natural species, which is represented by multiple ecotypes, is adapted to heterogeneous environmental conditions and challenges of nutrient competition, viral attack, and other stressors. An important consequence of this study is that expression patterns obtained under artificial cultivation conditions cannot be directly extrapolated to gene expression under natural conditions. Moreover, we found 195 significantly differential expressed genes between the seasons, with 140 genes being higher expressed in winter and mainly encode proteins involved in energy and carbon source acquiring processes, and in stress responses. [ABSTRACT FROM AUTHOR]

In the direct contact membrane distillation (DCMD) system, the temperature polarization due to boundary layer formation limits the system performance. This study presents the experimental results and heat transfer analysis of a DCMD module coupled with a salinity gradient solar pond (SGSP) under three different flow channel configurations. In the first case, the feed and permeate channels were both empty, while in the next two cases, the feed and permeate channels were filled with a porous spacer material. Two different spacer geometries are examined: 1.5 mm thick with a filament angle of 65°, and 2 mm thick with a filament angle of 90°. The study considers only the heat transfer due to conduction by replacing the hydrophobic membrane normally used in a DCMD module with a thin polypropylene sheet so that no mass transfer can occur between the feed and permeate channels. The Reynolds number for all three configurations was found to be between 1000 and 2000, indicating the flow regime was laminar. The flow rate through both the feed and permeate sides was the same, and experiments were conducted for flow rates of 5 L/min and 3 L/min. It has been found that the highest overall heat transfer coefficient was obtained with the spacer of 2 mm thickness and filament angle of 90°. [ABSTRACT FROM AUTHOR]

• Features, factors, and facets of solar pond design and construction. • El Paso Solar Pond experience as the basis for design specifications. • Design and planning ensure solar pond reliable and sustainable operation. • Purpose of solar ponds provides focus for design and configuration. Over the last four decades, salinity gradient solar pond (SGSP) science and technologies have advanced in practical projects. In this work, we show that understanding a salinity gradient solar pond's purpose provides the focus for preparing a preliminary design and physical configuration. This paper aims to share lessons learned in designing and constructing the El Paso Solar Pond. Features, factors, and facets of solar pond design and construction are presented straightforwardly to inform and guide planning for future work. Emphasis is on sodium chloride-based ponds, the base salt used for the El Paso Solar Pond. However, lessons learned are pertinent to additional salt source configurations. Reference to solar ponds operating in Australia and Israel provides design and construction insights. Careful design and planning prior to construction ensure the solar pond operates reliably and sustainably. [ABSTRACT FROM AUTHOR]

• The study deal with the stability of the SGSP with Soret effect and Dufour effect. • A SGSP is numerically investigated using a mutli-distribution Lattice-Boltzmann method. • Promising temperature and heat collection continuity are obtained. • Effect of buoyancy ratio on the temperature and concentration is analyzed. A mathematical model for multi-diffusive convection with Soret and Dufour effects is developed to simulate the behavior of a salinity gradient solar pond (SGSP) in this study. The influence of Soret and Dufour effects on the double-diffusive natural convection of the SGSP and also the distribution of velocity, temperature and salt concentration fields are discussed using distribution functions of the lattice Boltzmann method. The results show that the Soret effect plays a role in promoting temperature and concentration diffusion, while the Dufour effect has a certain suppression influence on temperature diffusion and improves the concentration diffusion. Moreover, the influence of the Soret effect in the SGSP is more obvious than the Dufour effect on double diffusion. Simultaneously, the relationship between the buoyancy ratio and the Soret and Dufour effects is also discussed. [ABSTRACT FROM AUTHOR]

Salt Gradient Solar Ponds (SGSPs) are conventionally operated wholly manually. They hence suffer from a loss of efficiency for substantial durations when disturbed by natural diffusion and environmental elements such as temperature variation, solar radiation, and wind. They also impose considerable operational costs and time when a repair is unavoidable. Here, a Zero-Discharge Closed Cycle (ZDClC) is proposed for sustainable implementation of control architectures. We then define the SGSP as a control system and propose an automatic approach that uses Artificial Intelligence (AI) to mimic experts' actions during repair operations. More specifically, an Automatic Supervisory Controller (ASC-SGSP) is proposed that decomposes the pond into several uniform sublayers according to their thicknesses and salt concentrations. The automated supervisor then uses a decision tree analysis of pond stability to determine the sequences of injection/suction actions to guarantee the pond stability and prevent layer overturning. An on–off subcontroller then directs the chosen sublayer's salt density to its desired value. The supervisory structure is general and can operate with either the proposed open-loop or closed-loop configurations. Results indicate the potential utility of AI and expert systems as a successful paradigm for SGSP control. Specifically, the proposed approach is examined in a simulated pond under several scenarios challenging its efficiency, adaptivity, robustness, and constraint handling properties. The ASC-SGSP fulfills the automatic control requirements during either open/closed-loop configurations and regulates the desired salinity levels under parameter constraints and uncertainties, even when the SGSP parameters are perturbed by as much as 50%. • A zero discharge closed-cycle sustainable implementation of controllers for SGSPs is proposed. • A proposed systems theory perspective leads to the automatic control of decomposed interactive MIMO sublayers. • Expert systems and AI analyze sublayers' interactions thru a sequence supervising decision tree. • Several subcontrollers manipulate the uniform sublayers according to the supervisor's recommended sequence. • The pond's efficiency and robustness confirm the success of the automatic salinity repairing. [ABSTRACT FROM AUTHOR]

Maintaining the temperature of the photovoltaic (PV) panel within the described standard helps in achieving higher power conversion efficiency. To regulate the PV temperature, phase change material (PCM)-based cooling techniques have been proposed in several literature. However, most of the studies utilize organic PCMs whose low thermal conductivity confines their potential. Thus, in the proposed work, the rear side of the 20 Wp PV panel is coated with hydrated salt-based PCM and is integrated with an aluminum sheet (PV-PCM-Al) to increase the thermal conductivity of the system. The effect of the PV-PCM-Al panel in enhancing the PV efficiency is realized by comparing it with a standard uncooled PV panel. This concept was experimented under direct sunlight for about a week in Chennai, the southern part of India. To perceive the performance enhancement, thermal images were taken for both the cooled and uncooled PV panels. In addition, open-circuit voltage, short-circuit current, and power output were measured. The experimentation is also backed up by numerical simulations to understand the heat transfer characteristic features of the designed integrated PCM and aluminum cooling system. The experimentation results highlight that a maximum increase of about 7.67% in the PV efficiency was obtained using a cooled PV panel when compared to an uncooled PV panel. A maximum increase of 7.34% in the open-circuit voltage and a maximum drop of 4.6 °C in the PV temperature were obtained. [ABSTRACT FROM AUTHOR]

The salt gradient solar pond (SGSP) is used to store solar energy for low-temperature applications. This study investigates experimentally the density and temperature profile of Magnesium sulfate (MgSO4) in a trapezoidal-shaped SGSP. Four identical trapezoidal solar ponds were constructed by using plywood. The sides of the pond were completely covered with polythene sheets and given a black coating. The experiments were conducted using four identical solar ponds for seven days with different concentrations of magnesium sulfate and identified that the 16% concentration of MgSO4 (SGSP-M16) is the optimum concentration. Further, the experiment is extended to a 16% concentration of MgSO4 with coal cinder (SGSP-C). The temperature difference between the lower convective zone (LCZ) and upper convective zone (UCZ) is of about 13.7 °C and 17.6 °C for SGSP-M16 and SGSP-C, respectively. It is also observed that maximum temperatures of 54 °C and 59.1 °C in the heat storage zone for SGSP-M and SGSP-C, respectively. This higher temperature in SGSP-C is owing to the low volume heat capacity and low thermal diffusivity of the coal cinder. [ABSTRACT FROM AUTHOR]

• Heat extraction using supercritical carbon dioxide from solar pond is proposed. • Optimized operating conditions are identified for heat pump applications. • Operating pressure primarily influences the heat extraction rate, followed by mass flux. • Heat extraction is increased by up to 85% compared to conventional systems. • Centrifugal force superiority over gravitational force in spiral coil tubes is identified. Heat pumps integrated with renewable energy sources represent an efficient approach to residential heating and cooling, with minimal environmental impact and reduced carbon emissions. While these systems have been extensively researched, there is a necessity to broaden their scope by investigating novel approaches to energy capture and storage that are adopted to the specific characteristics of the region. This study analyzes the effects of different operating parameters on heat extraction from a solar pond integrated with a heat pump using carbon dioxide under transcritical conditions. Subsequently, an optimization examination is conducted to assess and determine the conditions required to achieve the maximum heat extraction rate and the minimum pumping power. The outcomes of this investigation demonstrate that the carbon dioxide mass flux and operating pressure exert a greater influence on the responses compared to the inlet temperature of carbon dioxide and the lower convective zone temperature of the solar pond. Additionally, within the investigated range of mass flux, the highest level of heat extraction occurs at operating pressures near the critical point of carbon dioxide, approximately 7.5 MPa. To meet the demand for maximum heat extraction from the solar pond, the optimal conditions result in an overall performance improvement of 2.61 times compared to the reference state. Furthermore, optimizing the system to maximize heat extraction from the solar pond while using the minimum pumping power results in a total performance enhancement of 4.13 times. [ABSTRACT FROM AUTHOR]

• Integration of a 10,000 m2 area solar pond in a salt work is investigated. • A mathematical model is used for LCZ temperature prediction. • A simple method is presented for salinity gradient development. • Economic and environmental benefits are evaluated through a parametric study. • Construction and operating costs of the solar pond are estimated. The process of salt manufacture in a salt work in Sabzevar in Northeast Iran is presented. A multi-faceted application to integrate a salinity gradient solar pond as part of the salt work process is presented addressing the reduction of parasitic energy losses such as the energy used for salt rock crushing and saving the amount of fossil fuel (natural gas) needed for brine heating. The solar pond with an area of 100 × 100 m2 and depth of 3 m is proposed to be constructed on the site of salt work. A partitioning wall with some opening heights equal to the desired position of the interface of lower convective (LCZ) and non-convective zones (NCZ) in its lower section, divides part of the area of this pond, say 5 percent or 500 m2. The separated area is designated to act as a salt charger and salt storage. The rock salt deposited in the salt charger dissolves into the LCZ of the pond and produces hot saturated brine solution. Results indicate that 100 tons of pure salt may be obtained from the extraction of 320 m3 of hot saturated brine consisting of 73 wt% water and 27 wt% salt. This is the nominated daily salt production of the factory. The proposed system will help to streamline the process of salt manufacture and reduce the environmental footprint. Using locally available meteorological data of Sabzevar, it is shown that such a pond may produce hot brine at an average temperature of 65 °C in summer and 37 °C in wintertime with a loading of 20% of the input irradiation. The gradient zone of the pond may be setup by placing a layer of low salinity water over saturated brine, allowing for salt diffusion to take place. Formation of large amplitude surface waves increases the salt diffusion and a salinity profile will develop in few months. A parametric study was performed to assess the enviro and economic effects of the proposed 10,000 m2 solar pond. The amount of fresh water to be injected to the solar pond is calculated to compensate for evaporation of pond surface as well as production of concentrated brine containing 100 tons of salt per day. Computer simulation shows that about 59,000 MJ/day thermal energy may be extracted from the pond in June. This is equal to a saving of about 1,576 kg/day of methane. Considering the price of methane this would be a financial saving of 283 $/day. The rate of reduction in CO 2 emission is estimated to be 4,335 kg/day in June. Considering a carbon price of 30 $/ton, the above reduction in CO 2 will be equivalent to savings of 130 $/day related to the environment. These calculations are extended to all months of the year and results presented. For demonstration, feasibility of using an existing old cylindrical fuel storage tank (2,000 m3, 3.3 m deep) as a container for a 600 m2 outdoor solar pond nearby the factory buildings, is proposed for pilot study. The shading effect is examined by scaling down a 3D model of the reservoir and its adjacent buildings for different months of the year, using Helidon device available at RMIT University of Australia. According to the simulation performed, it seems that the presence of buildings around the fuel tank does not have a significant shading effect on the surface of the demonstration solar pond. [ABSTRACT FROM AUTHOR]