“Pyramid solar distillers: A comprehensive review of recent techniques”

The most interesting themes worldwide are those relating to sustainable water and energy supplies. They have a significant impact on any society's economic wellbeing. Desalination of brackish water has proven to be a good solution to the freshwater issue that many regions of the world face. Solar stills (SSs) are a simple distillation technique for freshwater purification. From the conventional SSs to the modified SSs, several studies have been carried out to improve the effectiveness of this technique. Pyramid solar stills are effective and efficient, according to researches that have been done to develop several types of solar stills for increased distillate production. In this review, we aim to provide an extensive review of recent advancements in pyramid solar distillation techniques, including new technologies, methods, and best practices. Consequently, this paper helps researchers choose the optimal technique to get the best-optimized productivity from a pyramid solar still. This review highlights the efforts of researchers to improve the efficiency of solar distillation systems by exploring recent techniques and innovations in pyramid solar distillers up to 2023. Various results have demonstrated the significance of modifications or improvements to pyramid SSs, such as utilizing storage materials, which can significantly increase productivity by approximately 35%. Additionally, a v-corrugated absorber with PCM can enhance the yield by about 87.4%. Furthermore, the use of wick materials can increase freshwater production by up to 122%, with jute wick outperforming cotton wick. Integrating evacuated tubes and carbon black nanofluid into a pyramid solar still can also improve freshwater production by approximately 57.1%. Combining nano and wick materials can further boost pyramid distiller productivity by up to 176% and increase thermal efficiency to 60.44%. Moreover, using pyramid distillers with revolving cylinders and electrical heaters can result in a daily output increase of 214%, producing up to 9100 ml/m2/day

A numerical investigation of the increase in heat transfer in a half-cylindrical container filled with phase change copper rods

Phase change materials (PCMs) are capable of storing and removing a significant quantity of latent heat from heating storage systems. PCMs such as paraffin wax are used because they store a large amount of energy in a relatively small space while maintaining a nearly constant temperature between solidification and melting. An investigation into the numerical effects of increases in heat transmission to paraffin wax (RT58), within a half-cylindrical cell which included a range of copper rods, was conducted to determine their impact. The enthalpy-porosity combination program ANSYS/FLUENT 16, was used in this study to ascertain levels of heat transmission that occur when varying numbers of copper rods are inserted in the container, as well as the impact this has on melting time. The findings show that increasing the number of rods results in a decrease in melting time. When comparing cells with three and five copper rods against a cell with no rods, the melting time is reduced by 45% and 52%, respectively. The findings of this research can benefit thermal energy storage applications such as cooling microelectronic devices, and storing and discharging thermal energy

Using different geometries on the amount of heat transfer in a shell and tube heat exchanger using the finite volume method

This research investigates the heat transfer and pressure drop characteristics of a conical spiral tube heat exchanger. The study specifically focuses on the application of Ag-HEG (Silver–Hydrogen exfoliated graphene) nanofluid and various turbulator designs. The range of Dean Numbers, specifically 2200 < Dean <4200, was studied through experiments under turbulent flow conditions. Furthermore, the finite volume method-based ANSYS Fluent commercial code was utilized for numerical simulations. Additionally, numerical simulations were performed using the ANSYS Fluent software, which utilizes the finite volume method. This research aims to perform a numerical analysis on the efficiency of a conical shell and tube heat exchanger. When compared to other models, spiral heat exchangers provide a larger contact area between the fluid and the exchanger within a specified occupied area. This advantage is one of the prominent features of this particular type of heat exchanger. The simulations were conducted in two stages. During the first stage, the thermal performance coefficients of three turbulators were evaluated. In the second stage, the four-blade turbulator with ten revolutions, which exhibited superior thermal performance, was further analyzed based on the number of circles around the center of the conical spiral coil. The numerical results showed that the four-blade turbulator with ten revolutions displayed superior thermal performance compared to the other modes, specifically the two-blade and three-blade turbulators. In the second stage, it was found that the Nusselt number achieved from 30 revolutions was higher by 4.2 %, 10 %, and 18.3 % compared to the Nusselt numbers obtained from the other two modes of 10 and 20 revolutions. Consequently, it is concluded that utilizing Ag-HEG nanofluids in conjunction with the four-blade turbulator featuring 30 revolutions is the optimal choice for improving heat transfer in conical spiral tube heat exchangers while maintaining an acceptable level of pressure drop. This combination outperforms traditional fluids and turbulators

Maximizing charging/discharging capabilities of horizontal shell-and-tube latent heat storage systems with innovative curved fin inserts

Inherent fluctuations in the availability of energy from renewables, remain a substantial drawback to their widespread deployment worldwide which can be solved by energy storage solution. Energy storage can also help to bridge the mismatch between the energy supply and demand by storing the excess and/or off-peak energy. This study introduces curved fin inserts as another effective enhancer for the thermal performance of the shell-and-tube latent heat storage module with RT35 as the key phase-change material (PCM) component. Various fin curvature angles are explored using enthalpy-based numerical simulations. Their effects are quantified on the PCM liquid fraction, average PCM temperature, melting/solidifying durations, and energy storage/removal rates. During melting at inlet temperatures of 50–70 °C, fins considerably enhance the thermal response of PCM. Curved fins with a 180° curvature angle yield the fastest melting, reducing time by 145.7 % compared to straight fins. Higher HTF and PCM initial temperatures also accelerate melting. For solidification with heat transfer fluid (HTF) at 10–30 °C, curved fins boost rates up to 395.3 % over non-fin cases. Optimized designs cut solidification duration by 79.8 % at lower HTF temperatures. Results demonstrate curved fins maximize charging and discharging rates up to 542.7 % and 467.0 %, respectively. Energy densities improve by 556.3 % against non-finned baselines. The outcomes provide important insights into the designing of efficient PCM-based storage components through the proper employment of tailored fin geometries

A technical appraisal of solar photovoltaic-integrated single slope single basin solar still for simultaneous energy and water generation

In the contemporary era, the availability of energy and water stands as an essential foundation for human survival, with water's significance underscored by its role in shaping habitats. However, the modern world faces the pressing challenge of water scarcity, exacerbated by factors like air and water pollution, leading to ecological imbalances. Water, an indispensable resource for various daily human activities, necessitates the generation of freshwater. Simultaneously, the imperative of sustainable energy generation has taken precedence on the national agenda for growth. In this context, the integration of solar photovoltaic (PV) technology with solar stills emerges as the most viable solution. Within these integrated systems, electrical energy generated by solar PV is strategically employed to preheat inlet feeds, enhance air temperature, and optimize the evaporation and condensation processes within the solar still, thereby augmenting its overall performance. This study delves into the integration of solar PV collectors/systems with solar stills, distinguishing between thermal and electrical energy utilization in solar PV systems. The review underscores the pivotal role of solar PV integration in addressing critical issues of water scarcity and sustainable energy generation, contributing to the nation's growth