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Solar thermal selective coatings (STSCs) are crucial for enhancing the thermal efficiency of receivers in solar power applications. Enhancing the photothermal conversion performance of STSCs is crucial for improving the thermo-economic efficiency of these sustainable high-temperature applications. Wherefore, in this study, we comprehensively review the ongoing technologies and enhanced strategies of solar thermal selective coatings, highlighting their advantages, drawbacks, technological advancements, and mechanisms. This review comprehensively examines the latest advancements in material synthesis, coating structure designs, and induced aging mechanisms of STSCs. It critically discusses the various types of STSCs, and the research techniques employed to assess photothermal performance and enhance thermal stability. Lastly, the limitations and future expectations of STSCs are also highlighted. This paper serves as a detailed guide for planning and implementing various types of STSCs in diverse solar power applications. [ABSTRACT FROM AUTHOR]

Thermal energy storage plays a vital role to solve the problems related to the intermittent nature of solar energy. Phase change materials (PCMs) have shown promising applications in different thermal energy storage systems. Cascaded Thermal Storage (CTS) PCMs (multiple PCMs in a descending order of their melting temperatures), added new advantages to the applications of PCMs in thermal energy storage systems. Solar water collectors (SWCs) that utilize PCMs have been used to achieve economic and environmental benefits via substituting large-scale demand of energy. This literature review focuses on the different developments of PCMs and CTSPCMs and their implementation in SWC storage tanks. The novel and most recent developments of PCMs and CTSPCMs utilized in solar storage tanks with SWCs, such as, multi-storage tank with cascaded PCM, packed bed storage units, different configurations of heat exchanger storage units, and other innovative storage tank designs, are reviewed and discussed. Furthermore, the existing studies that evaluated the PCM heat transfer improvement, thermal storage performance, thermodynamic optimization, and applications of cascaded thermal storage systems are also reviewed. The reviewed results in this work showed that the CTSPCM system can promote a significant improvement in the PCM heat transfer and stored rates of entransy, energy, and exergy, as well as lead to an increased storage energy and exergy efficiencies compared to the single stage PCM system. It is also revealed that: the multi-tank integrated with cascaded PCMs system is the best amongst the studied PCM storage tank systems within SWCs, for augmenting the storage capacity and improving the overall thermal efficiency of the water heating system. A noteworthy observations, important proportionalities, and future trends are also discussed for each technique. [ABSTRACT FROM AUTHOR]

In this work, the recent advances in solar-powered water desalination systems are reviewed in detail. The recently published designs of solar-powered desalination systems such as solar stills integrated with phase change materials, multi-effect distillation (MED), multi-stage flash (MSF), humidification-dehumidification (HDH), reverse osmosis (RO), and membrane distillation (MD) are reviewed and discussed. The water desalination systems driven by photovoltaic and concentrating solar power (CSP) are also of great interest in this review. The reviewed results reveal that photovoltaic-powered RO desalination systems are still at the top as the most common technique used for water desalination powered by solar thermal sources. Where this technique achieves high daily productivity per unit area of the solar field with considerably low cost compared. The conjunction between the MSF and the CSP plants is ranked second in this competition as the desalination system benefits from the heat recovered from the CSP plants. In addition, for development technology for solar-based distillation, an integrated system that is involved two membrane processes or the combination of these processes with solar thermal heating/electrification hybrids is acquiring much popularity. In high-salinity seawater distillation, the scrupulous choice of proper initial and post-treatments yields more thermoeconomic benefits in terms of energetic efficiency, specific freshwater product, cost per liter and specific energy consumption as well as the operational independence for off-grid applications. Overall, the surveyed findings and concerned comparisons for the diversified solar combinations are discussed critically. Finally, some future recommendations related to integrated solar desalination systems are also mentioned, which assist in creating newly pathways for decision-makers to explore efficient hybrid desalination methods. [ABSTRACT FROM AUTHOR]

In this paper, the design criteria, opt-geometrical parameters, thermal performance analysis, thermodynamic optimization, techno-economic aspects of Solar Dish Stirling Systems (SDSS) are presented. Moreover, experimental studies that analyze the status of standalone SDSS in various countries and the operational SDSS plants are also discussed. In addition, the applications of SDSS in solar power plants, hybridization and storage, micro co-generation, water desalination, and solar cooking are extensively discussed. The reviewed results revealed the superior role of the SDSS in distributed energy systems, which have high flexibility generated capacities range between 1.0 and 38.8 kW with overall efficiencies range between 13% and 32%, and generation costs range between 0.115 and 0.256 $/kWh, depending on dish concentrator size, design, and solar radiation level. Moreover, the paper also demonstrates the various novel ways to hybridize solar dish with micro gas turbines (SDMGTs) and other solar energy systems or emerging solar dish Stirling for micro co-generation systems (SDSMCOS). It is found that the SDMGTs have higher overall efficiencies of 18.35%–26.48% compared with that of SDSMCOSs which have total efficiencies of 16%–23%. Developing hybrid innovative multi-generation systems to generate electricity and heat with reasonable cost and higher thermal efficiency could help in accelerating the commercialization of dish-Stirling applications. In general, SDSS can provide promising environmentally and technically benefits, however, more efforts should be made to promote the feasibility of its commercial applications. Noteworthy discussions, important proportionalities, critical conclusions, and future strategies are also discussed as well. • The review includes the opt-geometrical and thermal analyses, and applications of solar dish Stirling systems (SDSS). • Analytical and ray-tracing approaches in the receiver cavity of SDSS for optical improvement are studied. • The potential contribution of simulation and optimization tools in respect of the improvement of the SDSS is identified. • An economic assessment and future strategies of electricity generation in SDSS is analyzed. • Recent advances of different applications based SDSS and their current challenges are discussed as well. [ABSTRACT FROM AUTHOR]

• Parabolic trough/parabolic dish-desalination plant designs were critically reviewed. • A performance assessment and economic analyses of hybrid desalination plants are analyzed. • RO plant powered by parabolic trough is more economical than parabolic trough-MED-TVC plant. • Hybrid MED-RO system with parabolic trough is a promising technology. • System performance characteristics, challenges, and future strategies are discussed. In this review, current status and recent progress in concentrated solar power (CSP) desalination technology has been presented. Special focus has been considered for designs and hybridization configurations, thermodynamic performance assessment, and economic analyses of hybrid solar desalination systems driven by only the parabolic trough, or/parabolic dish CSP systems. Studies that combined solar parabolic trough/dish with different desalination technologies such as multi-effect distillation (MED), reverse osmosis (RO), humidification-dehumidification (HDH), multi-stage flash (MSF), and thermal vapor compression (TVC) either for only freshwater production or for co-generation of power and freshwater are discussed in details. Comparison among the reviewed solar concentrated parabolic trough desalinating systems shows that the MED-TVC system powered by parabolic trough solar field is more appropriate than a parabolic trough-RO combination from a thermodynamic viewpoint. In addition, solar parabolic trough and dish collectors can operate the thermal cycles to drive RO desalination system with lower cost of producing water than the MED process. It can be concluded that adopting parabolic trough CSP-desalination technology was a better option for improving the economic advantages of hybrid CSP-desalination industry than adopting parabolic dish CSP-desalination technology. Furthermore, the hybrid MED-RO system with parabolic trough technology is characterized by high reliability, high freshwater generating efficiency, and low desalination cost. Nevertheless, more theoretical and experimental data are needed to optimize these hybrid systems to gain higher efficiency and lower operating cost in the future. [ABSTRACT FROM AUTHOR]

The low freshwater production of the solar distillers is one of the most crucial obstacles to their effective use in distillation applications. In this work, an attempt has been made to ameliorate the distilled yield of the hemispherical solar distiller. This was fulfilled by using a v-corrugated basin and reversed solar collector in order to augment the evaporation area and assist in reflecting more solar irradiance onto the outer surface of the v-corrugated basin. Two hemispherical solar distillers, namely; v-corrugated basin hemispherical distiller integrated with a reversed solar collector (VBHD-RSC) and traditional flat basin hemispherical distiller (TFBHD) were designed and examined at the same outdoors conditions of El-Oued (33°27′N, 7°11′E), Algeria. Moreover, a comparative energic-economic analysis of the two proposed hemispherical distillers has been conducted in terms of freshwater productivity, daily energy efficiency, and freshwater distillate cost. The results show that the daily accumulative yield of the VBHD-RSC was 7.85 kg/m2.day which was higher than that of TFBHD by 68.82%. Moreover, the daily energy efficiency was obtained to be 59.70% and 35.52% for VBHD-RSC and TFBHD, respectively. Furthermore, the economic assessment indicates that the usage of a v-corrugated basin embedded with a reversed solar collector was more cost-efficient as it reduces the cost of freshwater production by 27.12% compared to TFBHD. [ABSTRACT FROM AUTHOR]

• A detailed model was developed to simulate a DCMD system powered by solar heat pipe collectors. • Parametric analysis was conducted to figure out the influence of design parameters on system performance. • No. of the utilized solar collectors, feed flow rate, and cooling water flow rate were the most sensitive parameters. • Daily freshwater yield of 36 L achieved with a 1.0 m2 tubular module and 9.0 m2 solar field. Feed seawater heating is one of the crucial bottlenecks in membrane desalination (MD) systems. The interest of usage solar energy techniques for feed seawater preheating in MD systems is recently regarded as an improvement path for sustainable distillate production. This study presents a conceptual design, theoretical modeling, and comprehensive parametric analysis of a tubular direct contact membrane desalination system (TDCMDS) driven by heat pipe-based solar collectors (HPSCs). An improved theoretical model performed in MATLAB software was conducted to simulate the hybrid solar TDCMDS operation in order to analyse its performance in the climate conditions of Tanta, Egypt. The effects of the number of utilized solar collectors, feed seawater flowrate, cooling water flowrate, and utilization of additional electric heaters on the energy performance of the solar TDCMDS are parametrically investigated. The findings show that the number of the utilized solar collectors, feed seawater flowrate, and cooling water flowrate, were the most sensitive to the performance of the solar TDCMDS, which should be desired to be 5.0 ≥ n ≥ 2.0, 20.0 lpm, and 5.0 lpm, respectively, in the design of the TDCMDS to maximize the freshwater production. Moreover, the maximum permeates flux are 0.45, 0.39, 0.32, and 0.25 kg/h per m2 of solar collecting area with total daily freshwater production of 35.0, 24.60, 15.48, and 7.95 kg/day by integrating five, four, three, and two HPSCs connected in series, respectively, compared to only 0.08 kg/h.m2 and 1.44 kg/day when coupling one solar collector at feed seawater and cooling water flowrates of 20 and 5.0 lpm, respectively. Conclusively, it can be recommended that this investigation provides an emerging strategy for designing solar-based MD systems. [ABSTRACT FROM AUTHOR]

In the present work, a thermo-economic performance of the modified hemispherical solar still (MHSS) was studied and compared to traditional hemispherical solar still (THSS). The modulations accounted for two additives, namely: paraffin wax as phase change materials (PCM), and copper oxide (CuO) nanoparticles. Three cases of MHSS were investigated and compared to THSS: (0.3 wt%) CuO nanomaterials were immersed in the basin water, implementing PCM container below the basin, and combining PCM container below the basin plus mixing CuO nanoparticles in the basin water. The basin water depth in all stills was set at 1.0 cm in all cases. Moreover, the thermo-economic performance of the four studied cases was compared and evaluated by determining the freshwater productivity, the daily energy efficiency, and the freshwater cost. Experiments have been carried out on the proposed hemispherical distillers under hot climatic conditions of El-Oued (33°27′N, 7°11′E), Algeria. The results show that the single utilization of CuO/water nanofluid and pure PCM improved productivity by 60.41% and 29.17%, respectively, compared to THSS. While, the dual usage of PCM and CuO/water nanofluid further enhanced the productivity by up to 80.20%, relative to THSS. Moreover, the daily energy efficiencies of the hemispherical distillers under the different studied cases (THSS, MHSS/PCM, MHSS/CuO-water nanofluid, and MHSS/PCM + CuO-water nanofluid) were found to be 35.52%, 45.45%, 56.46%, and 63.61%), respectively. The economic feasibility of these modifications presented that the dual usage of PCM and CuO/water nanofluid is more effective as it reduces the cost of freshwater production by 75% compared to THSS. In the third distiller (Modified hemispherical solar still with 0.3 wt% CuO/water nanofluid (MHSS-CuO/water NF)), the modified was done by adding (0.3 wt%) copper oxide (CuO) nanomaterials to the basin water, to improve the thermal properties of nanofluid and increase the intensity of the absorbed solar energy. In the fourth distiller (Modified hemispherical solar still with paraffin wax as phase change materials and 0.3 wt% CuO/water nanofluid (MHSS-PCM + CuO/water NF)), it was designed and constructed a circular galvanized steel container 1 mm thick, 340 mm diameter, and edge height 40 mm, coated with the black pained. This container was placed inside the wooden basin of the hemispherical solar still. A gap of 20 mm thickness was maintained between the container and the wooden basin on the bottom side and sidewall. 2.0 kg of paraffin wax as phase change materials was placed in the gap between the container and the wooden basin, to store the solar energy in the periods of higher solar rays and recovery it in the periods of low solar rays and after sunset. Moreover, in this modification copper oxide (CuO) nanomaterials were also added to the basin seawater with a concentration of 0.3 wt%, to improve the thermal properties of saline water and increase the intensity of absorbed solar energy, and improve the rates of heat transfer. • Dual usage of PCM and CuO nanofluid has great influence on hemispherical distiller performance. • Thermo-economic performance of the modified hemispherical solar still was studied. • Dual usage of PCM and CuO/water nanofluid enhanced the productivity by 80.20%. • Dual usage of PCM and CuO/water nanofluid reduces the freshwater cost by 90%. • Daily efficiency of MHSS with dual usage of PCM and CuO/water nanofluid reached 63.61%. [ABSTRACT FROM AUTHOR]