Performance Of Pond Research Articles

Experimental investigation of salinity gradient solar pond with nano-based phase change materials

ABSTRACT 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.

ASSESSING THE IMPACT OF MANGROVES IN TRADITIONAL SHRIMP FARMING IN THE MAHAKAM DELTA USING A COST BENEFIT ANALYSIS

Mangroves began rapidly converting into shrimp-farming ponds in the Mahakam Delta, East Kalimantan, Indonesia. In 2000, the government launched the mangrove reforestation project, but the expected outcome was not achieved. Evaluation and recommendations are needed to attain the economic and environmental sustainability benefits of ponds with planted mangrove plants mandated by the government. This study examined the feasibility indicators of ponds with and without mangrove systems and analysed the feasibility of aquaculture pond performance. The results showed that the polyculture ponds with mangroves were more beneficial than the other pond systems, accruing more than 3.55 million IDR/ha/yr in net income. The polyculture pond with 10% mangroves showed the highest feasibility and benefits. The NPV, IRR, BCR, and PP were IDR72 million/ha/yr, 22%, 2 and 4.8 years, respectively. Therefore, the polyculture ponds with 10% mangroves were the best recommendation for farmers for the next 25 years. Government policy should facilitate improving environmental quality and sustainability in the Mahakam Delta.

Performance of Solar Pond Integrated with Thermoelectric Generator: A Theoretical Study

Performance of Solar Pond Integrated with Thermoelectric Generator: A Theoretical Study

Analysis of portable solar concrete ponds by using coal cinder to trap thermal energy of sustainable building using artificial intelligence

Cinder is a waste product made from the coal residue left over from power plant blast furnaces. Solar energy is a promising renewable energy source, but because of its erratic availability, energy storage technologies must be used. Our research suggests employing coal cinder (CC) to boost the thermal energy stored in transportable solar concrete ponds, combining rock mechanics with renewable energy. The concepts of renewable energy and rock mechanics are combined in this invention. Additionally, because it doesn't release any pollutants into the sky, it is great for low heat applications like building cooling and heating. However, due to its sporadic nature, solar energy requires effective energy storage to be used at night and in cloudy weather. By adding coal cinders to the bottom layer of a solar concrete pond in order to increase its heat energy, this work integrates rock mechanics with sustainable energy. A variety of small-scale research use the standard micro solar concrete ponds. Also offered is a numerical calculation for predicting energy development over a sizable area of a solar pond with a salt gradient. The coal cinders may significantly raise the temperature at the pond's bottom. With a constant temperature differential of 30 °C and 20 °C throughout the gradient layer for two different pond sizes with depths of 1.5 m and 1.0 m, this study provides thermal analysis of a salt gradient solar pond using machine learning as Particle Swarm Optimization (PSO) and extracting heat from the Lower Convective Zone (LCZ). Going through the regression indices (RMSE, R2, r), the energy efficiency (heat) of the first 1.5-meter-deep concrete pond varies between 22.1 and 11.3% throughout the winter. The energy performance of a solar pond decreases dramatically when the non-convective zone thickness and its size are decreased. For the two concrete ponds with depths of 1.5 m and 1.0 m, respectively, the annual average efficiencies are 23% and 16%. Hence, the solar pond demonstrates that it is an effective method for utilizing solar energy and may be a useful option for low-temperature energy needs, such as room heating.

Solar pond integrated with parabolic trough solar collector for producing electricity and hydrogen

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=0.350kg/s, m˙2=0.355kg/s, m˙3=0.360kg/s, m˙4=0.365kg/s, m˙5=0.370kg/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.

Design and performance analysis of salinity gradient solar pond under different climatic and soil conditions.

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.

The investigation of heat storage efficiency of salt gradient solar pond with and without phase changing materials

AbstractIn 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.

Heat transfer enhancement in solar pond using nano fluids

This paper aims to develop a Computational Fluid Dynamics (CFD)-based simulation analysis of a solar pond to investigate the double-diffusive nature of temperature or saline concentration distributions. Thus, the formation of such a stable three-layer system, as well as the incorporation of energy storage can be done. For this simulation study, we calculate the exit temperature for both the Phase change material (PCM) and non-PCM, while the input temperature is adjusted from 300 K to 340 K in 20 °C intervals. Further, the performance of a solar pond with PCM/non-PCM + nanoparticles is measured while tubes are kept on the same and opposite sides of the solar pond. The results showed that, when PCM containing nanoparticles is inserted and the tube intake and outflow are retained on the same side of the solar pond, the heat transmission is optimal.

Oxygen Transfer Rate Efficiency of Paddle Wheel Aerators in Intensive Shrimp Ponds

The purpose of this study was to determine the oxygen transfer rate efficiency of paddle wheel aerators in intensive shrimp farming. This study was conducted with the causal ex-pose facto concept by comparing the performance of paddle wheel aerator. The results showed that water quality in Pond 1 (1 HP) and Pond 2 (2 HP) only brightness which do not comply with water quality standards. The oxygen transfer rate paddle wheel aerator was 1 HP of 3.20 (2.82-3.65) mgO2/hours and for 2 HP of 2.12 (1.68-2.89) mgO2/hours. The dissolved oxygen in Pond 1 (1 HP) was 5.25 mg/L and Pond 2 (2 HP) was 5.63 mg/L. The shrimp growth rate in pond 1 is 1.95 (0.01-4.0 gr/day) and pond 2 is 1.25 (0.01-2.55 gr/day). Dissolved oxygen in pond 1 (1 HP) ranged from 4.15-7.26 mg/L and pond 2 (2 HP) ranged from 4.03-8.31 mg/L. Dynamic modeling results show a description the energy input to paddle wheel aerator will gradually decrease from 2 kW to 0.25 kW. The results of this study concluded that the use of a 1 HP paddle wheel aerator has a better oxygen transfer rate and shrimp pond performance than using a 2 HP paddle wheel aerator.

Performance monitoring of constructed floating wetlands: Treating stormwater runoff during the construction phase of an urban residential development

In the context of climate change and global trend towards greenfield urbanisation, stormwater and transported pollutants are expected to increase, impairing receiving environments. Constructed floating wetlands (CFWs) can improve stormwater retention pond performance. However, performance data are currently largely restricted to mesocosm experiments, limiting design enhancement fit for field implementation. The present 12-month field study aims to fill part of these gaps by identifying limitations and necessary design improvements for CFWs on a large retention pond/lake. Water in a 2.6-ha lake receiving stormwater from a 45-ha urban area under development in subtropical Queensland, Australia, was recirculated during dry weather periods to minimise algal growth and the risks of blooms. Pollutant removal efficiencies of two full-scale CFWs were evaluated during storm events and dry weather periods as a function of inlet and outlet pollutant concentrations, flow and rainfall. Inlet TSS and TN concentrations in runoff during the construction phase of the development exceeded required water quality limits while TP inflow concentrations were low and often below the detection limit. Median pollutant load reduction efficiencies during storm-events were − 20 % TSS, −2 % TN and 22 % TP at CFW1 and 51 % TSS, 3 % TN and 17 % TP at CFW2, respectively. TSS and TN concentration removal efficiencies at CFW1 were low and highly variable, partly due to low inlet concentrations, high flow velocities and short hydraulic retention times (<1 day). However, CFW1 significantly reduced TSS concentrations during dry weather periods. In contrast, CFW2 significantly reduced TSS concentrations during both storm events and during inter-event periods. This study highlights treatment limitations associated to the operational conditions of CFWs at field-scale not identifiable in a mesocosm-scale study. Further research is necessary to investigate treatment performance of CFWs during the operational phase of the development with higher nutrient levels.

Microalgae-based wastewater treatment for micropollutant removal in swine effluent: High-rate algal ponds performance under different zinc concentrations

Despite the social and economic importance of swine farming, this activity has great polluting potential due to the large wastewater generation composed of high micropollutant concentrations, such as trace metals (Zn and Cu). Microalgae can integrate the solutions to overcome these challenges by obtaining value-added biomass, closing the loop for an environmentally and economically sustainable wastewater treatment technology. Therefore, this study aimed to identify the interference of different Zn concentrations (0.5 to 70 mg/L) in SW on the performance of high-rate algal ponds considering real treatment and biodegradation conditions via microalgae. The innovative results showed that N-NH4+ removal was compromised with high Zn concentrations due to nitrification inhibition. Oppositely, the removal of soluble P was enhanced under conditions that favored algal growth (40 and 55 mg Zn/L). Moreover, Zn conferred an increase in soluble chemical oxygen demand that changed from 190 mg/L at the beginning of the treatment to 624 mg/L at the end due to extracellular polymeric substances production. Sequential chemical extraction demonstrated that biomass growth had an important contribution to Zn removal; however, it did not exceed the contribution of carbonates (28.7–44.2 %). The biomass characterization showed that Zn did not significantly affect the levels of proteins (41.2–53.5 %) and carbohydrates (34.0–43.5 %), while the lipids content was higher (18.2 %) in 55 mg Zn/L. The effects of Zn on nutrient removal and the biomass's biochemical composition must be pondered to combine the recovery of metals and nutrients and the production of value-added biomass.

Modification of hydraulic retention time in open raceway ponds to prevent rotifers and cladocerans establishment

Cost effective strategies to control zooplankton density in open pond algal cultures are not currently available, and those successfully tested at pilot-scale are generally difficult to implement at full-scale.Here we propose a method to calculate the hydraulic retention time (HRT) for open raceway pond algal cultures, below which undesirable zooplankton species would be prevented from establishing. We hypothesised that a HRT shorter than the generation time (GT) of zooplankton species should prevent their establishment by flushing the individuals out of the pond before they can reproduce. We reviewed published GT data of zooplankton species known to be detrimental to open raceway ponds performance and plotted GT against temperature over the range typical of algae pond operation (10 to 30 °C). We fitted trend lines to describe how the shortest, average, and longest GT of each zooplankton genera or species varies with temperature. We then validated the method against 29 months of operational data from two identical 8 m3 wastewater high rate algal ponds. Finally, we tested the method in a laboratory experiment performed under favourable growth conditions.Validation of the method against actual operation data showed that rotifers did not establish when HRT was shorter than their GT. However, cladoceran establishment was not predicted by the method likely due to their stratification in the water column depending on the intensity of the solar radiation and resulting avoidance of the pond outflow. The laboratory experiment confirmed that rotifers cultured under favourable growth conditions established at the shortest GT predicted by the method and HRTs shorter than the GT eradicated rotifer populations.We propose that operating ponds with HRTs that are up to ∼20 % shorter than the actual pond HRTs will control densities of zooplankton species evenly distributed in the water column to low levels.

PALMİTİK ASİT KULLANIMININ GÜNEŞ HAVUZUNUN SICAKLIK DAĞILIMI ÜZERİNE ETKİSİ

Solar energy is one of the renewable energy sources and widely used to obtain thermal energy. The heat obtained from solar energy can be stored by using different systems. One of these systems is solar ponds. Solar ponds consist of layers whose salt density increases towards the bottom. In this study, the use of phase change materials to increase the heat storage performance of a model solar pond was investigated. The phase change material, Cetyl-palmitic acid eutectic mixture was prepared and its chemical properties were obtained by FT-IR spectroscopy. The thermophysical properties and surface morphologies were determined by using Differential Scanning Calorimetry and SEM. The obtained phase change material was applied to the inner surface of the heat storage zone. The temperature distribution of the solar pond was calculated numerically for with and without phase change material. As a result, it has been seen that the use of phase change materials with suitable thermophysical properties in solar ponds will contribute to long-term heat storage performance.

Long-term effects of duckweed cover on the performance and microbial community of a pilot-scale waste stabilization pond

Duckweed-based ponds (DP), as a modified type of waste stabilization ponds (WSP) are receiving growing attention due to the sustainable production of high-quality duckweed biomass. However, the comprehensive effects of duckweed cover on nutrient removal, greenhouse gas emission and microbial community of the WSP have rarely been studied. In this study, two pilot-scale WSP (12 m2) with (DP) and without (OP) a duckweed mat on the surface were compared over 1 year to determine the effects. The results showed that, compared to OP, DP had higher TP, but lower TN and NH4+-N removal efficiencies, and lower pH, dissolved oxygen (DO) and sedimentation rate of settling detritus. For both nitrogen and phosphorus removal, the dominant pathway was duckweed uptake (66.95% and 93.18%, respectively) in DP; however, it became other pathways (mainly nitrification/denitrification, 82.27%) and sedimentation (87.65%), respectively, in OP. Meanwhile, DP had lower N2O, but higher CH4 emission fluxes than OP, resulting in comparable global warming potential between OP and DP (approximately 2800 g CO2/m2/yr). Microbial community analysis indicated that the greater nitrogen removal and N2O emission in OP could be attributed to higher abundance of ammonia-oxidizing bacteria in the water and denitrifiers in the sediment, supported by higher DO and settling organic carbon, respectively. Meanwhile, the greater CH4 emission in DP could be attributed to higher abundance of methanogens and syntrophic methanogenic bacteria in the sediment. Thus, despite favourable effects on nutrient recovery and phosphorus removal mainly attributed to duckweed uptake, duckweed cover had unfavourable effects on nitrogen removal and CH4 emission reduction of the WSP mainly attributed to microbial taxa which were influenced by environmental conditions (such as DO and settling detritus) in the WSP. These findings help to clarify the influencing mechanism of duckweed cover, providing overall insight into the function and application of the DP.

Intensive Litopenaeus vanamei pond performance with irrigation system based on Distribution of Vibrio spp.

Intensive shrimp ponds are characterized by the high stocking density of shrimp and artificial feeding and are equipped with an irrigation network system. The purpose of this study was to analyze the intensive L.vannamei pond with an irrigation system based on Vibrio spp. distribution to determine environmental quality degradation in terms of the treat of pathogenic bacteria. This study was carried out for one production cycle from March toJuly 2021 in an intensive shrimp farm in Sarjo Village, Pasangkayu Regency, West Sulawesi. The parameters analyzed in this study consisted of Total Bacterial Count (TBC), Total Vibrio Count (TVC), yellow and green colony Vibrio spp. in water using the spread plate method. Water samples for bacterial analysis were taken from 1) source water: (a) surface (0–50 cm depth) and (b) pump mouth; 2) treatment pond; 3) aquaculture pond; 4) Waste Water Treatment Ponds (WWTP); 5) outlet (before discharge into public waters). The results showed that the distribution of bacteria from seawater to WWTPs pond still increased the abundance of Vibrio spp., although the abundance of Vibrio spp. is still safe or below the maximum limit of 104 CFU/mL. Distribution of Vibrio bacteria in Intensive L.vannamei Pond Sarjo Village, West Sulawesi gave a relatively good pond performance because it was characterized by an abundance of Vibrio bacteria in the pond irrigation system from inlet to outlet which was still below the maximum limit and high pond productivity.Keywords:Intensive shrimp pondPathogenicVibrio spp.Pond performanceAquaculture

Effect of PCM melting temperature on solar ponds performance: Design and experimental investigation

Salt gradient solar pond (SGSP) is a technology which uses a renewable source such as solar energy to store thermal energy in a saline solution. Traditional SGSPs work in the sensible zone, increasing its temperature as the solar radiation is absorbed. SGSPs suffer from a low stability and energy efficiency, mainly caused by the high temperatures reached. At high temperatures, higher heat losses correspond. PCMs are characterized by high latent heat and a solid-liquid phase change at a nearly constant temperature. A pond integrated with PCMs can store the same amount of energy at a lower temperature, improving thermal efficiency and stability. In this paper, a pond integrated with PCM (RT35 HC) and a traditional one were designed, built and tested to evaluate the different performance. According to results, over ten days, the average temperature in the pond with the RT35 HC is about 4 °C lower (corresponding to the 5.7 %). Then a second experimental analysis was conducted comparing two different melting temperatures (RT35 HC and RT44 HC). Results show that a higher melting temperature enables to smooth the high peaks of temperature. While a lower melting temperature guarantees a higher and more stable temperature at night, due to the release of latent heat, making the application useful in case of constant temperature demand at the outlet fluid. Results are widely discussed in the paper.

Thermal-salinity performance and stability analysis of the pilot salt-gradient solar ponds with phase change material

Transient evolution of thermal and salinity behaviors of two pilot salt-gradient solar ponds with and without Paraffin Wax (PW) as the phase change material (PCM) were studied. Detailed thermal and salinity parameters were measured experimentally and various stability methodologies were used and compared to determine the effects of the PCM on the stability of the solar ponds, its operating principle, stability criteria and methods, salinity gradient formation, obstruction, and remedies. In addition, three different methods of heat extraction were examined. Both experimental and analytical results supportively indicate that the upper and lower boundaries of the salinity gradient can be the potential source of instability. The pond using PCM (SPP) achieved higher thermal and salinity stability, higher average outlet temperature for internal heat exchanger, and less temperature drop during heat extraction in comparison than the pond without PCM (SP). The use of PCM controlled the minimum and maximum temperature of the pond leading to higher evaporation (8.4%) in the SPP. It posed a positive effect on thermal efficiency during high-rate or long-term heat extraction. Heat extraction from NCZ influences the stability of the non-convective zone (NCZ), therefore, heat extraction from the convective layer is more suggested.

Mechanism and performance of algal pond assisted constructed wetlands for wastewater polishing and nutrient recovery

The limitation of oxygen and carbon source restricted the TN removal in constructed wetland (CW). Algal pond (AP) could produce oxygen and fix CO2 to improve C/N ratio in water. Therefore, an AP-CW system was established under laboratory conditions to deeply explore the effect of nutrient load distribution and microalgae addition in CWs on pollutant removal. This study showed that AP-CW could remove 49.7% TN and 90.0% TP with no carbon addition in CWs. The significant removal of NH4-N by AP advanced the location of denitrification in CWs. To enhance TN removal, different dosage of microalgae were intermittently added at 20 and 10 cm respectively below the inlet of the vertical flow CW1 and CW2, where the rest NH4-N has been almost oxidized into nitrate. The addition of microalgae influenced the microflora and effluent quality. Microalgae dosage in denitrification area significantly increased the absolute abundance of Σnir. The best TN removal of AP-CW could reach 91.3% when 8 g (dry weight) microalgae was added. However, unlike previous knowledge, microalgae as an organic carbon source would also release N and P during decomposition, leading to increased nutrients in the effluent. The optimal dosage of microalgae was 1 g/5 d in this study. The position and amount of microalgae addition in CWs should be adjusted based on water property and element flow to achieve the best pollutant removal and biomass harvest.

Numerical modelling of hydraulic efficiency and pollution transport in waste stabilization ponds

This paper investigates the hydraulic performance and solute transport processes in waste stabilization ponds (WSPs). A numerical model comprised of Reynolds-averaged Navier–Stokes (RANS) flow hydrodynamic model with the standard k − ε turbulence closure coupled with the advection-diffusion solute transport model, is developed in a three-dimensional Cartesian coordinate system. The proposed numerical model is successfully validated against laboratory-scale physical modelling measurements of flow hydrodynamics and solute characteristics across trapezoidal pond geometry. The developed numerical model is adopted to run series of scenario-based simulations to investigate the effects of WSP's geometrical features and implementation of an island retrofitting on the hydraulic performance and treatment efficiency of the WSPs. Fifteen pond configurations with varying side-walls slope and island configurations are simulated. Vertical and horizontal structures of flow hydrodynamics across the pond are investigated. Solute transport processes are studied through determining residence time distribution (RTDs) curves based on numerical tracer simulations. Two deflector island configurations (parallel and rotated) are simulated to investigate their influence on enhancing the hydraulic performance of the WSP. The analysis of the numerical results indicates an overall positive impact of deflector island retrofitting on the hydraulic performance of the WSP. The side-walls slope are shown to play a key role in determining the overall performance of the WSP. For the cases with side-walls slope of 1:1, 0.5:1 and 0:1, the hydraulic efficiency of the WSP was enhanced by adding both parallel and rotated islands. However, for the cases with side-walls slope of 2:1 and 1.5:1, addition of island deflector is shown to have negative impacts on the hydraulic performance of the waste stabilization pond.

MODELISATION AND NUMERICAL SIMULATION OF SALT GRADIENT SOLAR POND: THE ALTERNATING DIRECTION IMPLICIT METHOD

Solar energy as free and abundant energy is considered among the renewable energy that can replace disappearing fossil fuels. Many solar power systems can be used to capture this energy, but the majority does not have the ability to store this energy in different weather and time conditions. Therefore, salinity gradient solar ponds used in the present work can overcome this issue by simultaneously capturing and storing solar energy. A solar pond is being built at Annaba. In this present work we consider two identical solar ponds subjected to the same solar radiations during a period of 28 days, and exposed to the same climatic conditions, initial and at the limits. in the first pond, nanoparticles of conductive metal, namely copper, are injected with a concentration of $0.09\%$, while the second pond does not contain any nanoparticles. a comparative study was carried out on the temperature profile in the two solar ponds mentioned above to see the influence of nanoparticles on the thermal performance of the solar pond. The mathematical model adopted in this work is based on the equation of heat conduction in two dimensions with an external source of energy to the system. The method of finite differences with ADI scheme was used to determine the temperature distribution in two different directions according to the horizontal axis ox and to the vertical axis OZ representing the depth. An average temperature and insolation values for the last ten years were obtained using the data provided by Annaba saline station. Finally, a comprehensive study was carried out in order to highlight the convergence, consistency and stability properties of the discrete model representing the solar pond.