Conventional Solar Pond Research Articles

A unique solar pond system integrated with chlor-alkali electrolyser for heat storage and hydrogen production

Solar ponds are recognized as a simple, but a unique solution for renewable heat storage to use later. A freshwater feed to solar ponds is considered a crucial requirement to maintain the salinity gradient accordingly for heat storage purposes. This study aims to benefit from this specific requirement for solar ponds by integrating chlor-alkali electrolysers to produce hydrogen along with heat storage, which is a common purpose of a solar pond. Therefore, the proposed system establishes a desirable synergy, as per the sustainable development goals, between a conventional solar pond and an innovative high-tech hydrogen production system. In order to produce hydrogen, the saline water withdrawn from the upper convective zone is used in a chlor-alkali electrolyser powered by solar PV in order to produce green hydrogen. Thus, a conventional solar pond is converted into an integrated energy system that produces hydrogen and chlorine for useful purposes, along with heat storage capability. The system’s performance has been assessed in terms of the energy and exergy efficiencies for five distinct cities located in different countries that are grappling with poverty. The system’s performance, which is assessed in five cities, demonstrates the energy and exergy efficiencies ranging from 11.66 % to 14.56 % and 6.84 % to 8.60 % for the solar pond. They vary from 21.95 % to 24.22 % and from 14.23 % to 14.66 % for the overall system, respectively. Furthermore, the system effectively captures and stores solar energy, and it reaches temperatures up to 89.1°C. Moreover, the proposed system is expected to contribute to the United Nations’ Sustainable Development Goals by addressing energy poverty, promoting clean energy, and fostering economic growth.

Numerical and experimental study of effect of paraffin phase change heat storage capsules on the thermal performance of the solar pond

In this paper, the effect of adding the composite PCM (Phase Change Material) heat storage capsules to the heat storage layer of the salt gradient solar pond on the thermal performance of the solar pond was studied numerically and experimentally. Based on the program-controlled temperature simulation of the solar pond experimental platform, the effect of adding the composite PCM (48–50°C and 58–60°C melting point paraffin) heat storage capsules on the solar pond temperature and stability was studied, and a numerical simulation model was established to be compared by the experimental results. The results showed that the experimental temperature was consistent with the simulation results; the solar pond with PCM capsules had a smaller temperature change range than the conventional solar pond during the phase change process, but it did not have such effect in the non-phase transition process; in terms of flow, the addition of the PCM phase change units could reduce the flow rate of the heat storage zone, and the PCM with a larger latent heat had a more obvious suppression effect on the flow. Therefore, within a certain temperature range, adding PCM units to the solar pond had a positive effect on maintaining the stable temperature and stability of solar pond.

A new perspective to the conventional solar pond technology to increase the thermal efficiency

AbstractIn this study, a new perspective was introduced to conventional solar pond technology to spread its commercial application. In order to make it more useful with preserving energy efficiency, the brine layers were replaced with the normal freshwater by using a separated transparent partition. Structurally modified three different solar ponds were proposed and numerical investigations were conducted by using discrete ordinate method (DOM). For this, four types of solar ponds were modeled, the first one is the conventional salt‐gradient solar pond and three others are modified versions which are named as “Pure Water Solar Pond.” For all models, a comprehensive finite element method was developed to investigate the daily performance of solar ponds by using commercial software COMSOL. Salt‐gradient solar pond consists of seven layers where one layer is the heat storage zone, five layers are nonconvective zone, and one is the upper convective zone. However, in the modified models, solar ponds consist of two glass layers and one to three pure water zones depending on the model types. The numerical method includes a novel approach to calculate all the zone where absorption, emission, scattering, transmission, convection, and radiation are taken into account. Numerical results for all models were compared with an experiment to correlate the numerical accuracy of the DOM with anisotropic scattering phase function. Results indicate there is a good correlation between these four model approach and the experiment.

Experimental Study of Solar-Powered Desalination Pond as Second Stage in Proposed Zero Discharge Desalination Process

An experimental scale desalination pond which utilizes solar energy as a heat source is studied in this paper. The marked solar desalination pond is considered as one of the main stages in a proposed zero discharge desalination process. The effluent waste water of the desalination unit of the petrochemical complex is treated in the proposed zero discharge desalination process to produce potable water and salt. Evaporation distillation method is used in the studied solar desalination pond. Basically, this solar desalination pond is working as batch stage. At the first, the solar-powered desalination pond is introduced then the used method for distillation is discussed and the experimental results are represented in this paper, finally. The results show the feasibility of using the proposed solar-powered pond. The rate of gained distilled water by the proposed solar powered pond is compared with conventional solar pond, finally.

Energy efficiency assessment of integrated and nonintegrated solar ponds

In this study, an experimental investigation of temperature distribution and efficiencies in conventional solar pond (SP) and integrated SP (ISP) systems is presented. Several temperature-measuring sensors connected to a data acquisition system are used to measure the temperature changes with respect to time and position. In addition, the monthly stored energies of SP and ISP are determined. The maximum and the minimum energy efficiencies of the SP and ISP are observed for the months of August as 28.41 and 33.55% and January as 8.28 and 9.48%, respectively. These then confirm that the SP storage efficiency can be increased by integrating the system with solar collectors.

Spectral and Total Transmittances of Sodium Chloride and Potassium Chloride Water Solutions.

We describe the measurements of spectral transmittance and the calculations of the total transmittance for sodium chloride and potassium chloride water solutions. The spectral transmittance of NaCl and KCl water solutions over the infrared and nearby regions increases with increasing salinity. In the visible region, the spectral transmittance of NaCl w-s increases slightly, while that of KCl w-s decreases with increasing salinity. The total transmittance of the two salt water solutions can also be calculated by means of an integral method and a simple 5-partition method over 0∼3 m water depth. The simple method is of practical use to calculate the total transmittance for a conventional solar pond, because the rate of error between the two methods is about 10% at shallow depth and 0% at 3 m depth.

Spectral and Total Transmittances of Magnesium Chloride-Water Solution.

We report measurements of the spectral transmittance and calculations of the total transmittance of magnesium chloride-water solution to be used as the working fluid for a solar pond. The spectral transmittance of MgCl2-water solution in the visible, infrared and nearby regions decreases with increasing salt concentration. The total transmittance of MgCl2-water solution can be calculated using an exact integration method and a simple 5-band partition method over a 3 m depth of pond water. The simple method is useful in practice to calculate the total transmittance for a conventional solar pond, because the rate of difference between the results calculated by the two methods is less than 10% at shallow depths and then it decreases rapidly being followed by 0% at a depth of 3 m. Furthermore, the absorption coefficient calculated from the spectral transmittance of the present work is compared with that from Usmanov's data as shown in references (6) and (7).

The advanced solar pond (ASP): Basic theoretical aspects

This manuscript concerns the possible improvement of the conventional solar pond (CSP) performance by applying a multiselective injection and withdrawal procedure. We apply the term advanced solar pond (ASP), for a solar pond (SP) in which such a procedure is applied. The multiselective injection and withdrawal procedure creates in the SP a stratified thermal layer, namely a flowing layer which is subject to salinity and temperature stratification. This phenomenon is associated with reduction of heat losses into the atmosphere and an increase of the temperature of the fluid layer adjacent to the SP bottom. In the framework of this study transport phenomena in the ASP are analyzed and simulated by applying a simplified mathematical model. The analysis and simulations indicate that the multiselective and withdrawal procedure may significantly improve the performance of the SP.

Electrochemical solar ponds hybrid thermal and electric storage

A hybrid thermal and electric energy collection and storage system for solar application is proposed. Hybrid storage is achieved by transforming a conventional solar pond into a secondary activity cell, where the inert electrolyte (NaCl solution) has been partially replaced by active ones totally soluble on both oxidated and reduced phases, which produce highly reversible reactions. The tested REDOX pairs were: Pb/Cr ++ , Cr +++ , H 3 O + //Fe +++ , Fe ++ , H 3 O + /C Pb/Cr ++ , Cr +++ , H 3 O + //Cr 2 O 7 = , Cr +++ ,H 3 O + /C. The suggested hybrid system has been designed for static operation and large storage capacity. Changing the solar pond into an electrical accumulator improves thermal efficiency of the pond and does not increase building expenses; furthermore solar pond high temperature is advantageous for the accumulator operation and helps for current extraction.

Simulation of a Solar Pond With a Stratified Storage Zone

Numerical simulation results are presented which compare performances between a conventional solar pond and a proposed solar pond configuration. The proposed pond maintains a stratified storage zone below the lower convecting zone of a pond. Addition of a stratified storage zone is shown to have two general results. First, ground losses are minimized, and second, higher process temperature levels can be accommodated. Additionally, the proposed configuration may result in a reduction of pond investment cost.