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Solar energy harvesting and storage are essential in the future mix of renewable energy technologies. Hierarchical coral‐structured coatings have been shown to yield high solar absorptance in concentrating solar thermal (CST) systems. However, interfacial delamination and scalability challenges owing to material complexity pose significant hurdles for the widespread industrial adoption of these hierarchical CST coatings. Here, a coral‐structured coating is proposed whose black pigments are strongly bonded by titania, which is a material that mitigates interfacial delamination. Importantly, this coating follows a facile deposition procedure suitable for large‐scale solar receivers. The drone‐deposited coating inhibits cation diffusion and maintains a stable solar absorptance of 97.39±0.20%$97.39\pm 0.20\%$ even after long‐term (3000 h) high‐temperature (800∘C$800 \,^{\circ }\mathrm{C}$) aging. The scalability of developed coating represents a substantial advancement in the implementation of light‐trapping enhancement and maintenance approaches across a wide range of CST applications. [ABSTRACT FROM AUTHOR]

This article examines the prospects of Scheffler solar receivers integrated into renewable energy power plants for civil applications. This kind of solar receiver can offer satisfactory energetic performance with acceptable energy conversion efficiency when compared to other technologies to harness solar energy since the high-quality focal receiver can reduce heat losses also supposing great levels of evaporation temperature. In this research, energetic optimization and a broad assessment of Scheffler-type solar receivers are thoroughly conducted for variable sun radiation and considering a broad range of working conditions. To achieve this goal, thermodynamic optimization of the chief factors was attained via a numerical model which calculated the energy efficiency of the Scheffler solar receiver at part-load working conditions by computing all energy losses negatively affecting the heat exchange phase in the cavity receiver. The results obtained in this study show that the solar collector efficiencies of Scheffler receivers appear more promising than that of usual parabolic trough collectors; moreover, Scheffler receivers persisted with less sensitivity to reductions in solar radiation intensity. For these reasons, solar power systems based on Scheffler-type systems can be used from tens to hundreds of kW to ensure the energetic supply of small urban settlements with acceptable efficiency, optimistic investments, simple construction and reduced overall sizes. [ABSTRACT FROM AUTHOR]

Experimental investigations have been conducted to study the convective heat transfer from a cylindrical solar cavity receiver with vertical fins. The experiments were performed under varying surface heat flux levels and at seven inclination angles, ranging from −90° (upward facing) to +90° (downward facing) at 30° intervals. The impact of fins on the heat transfer process was studied by conducting experiments in two scenarios, namely, finned and unfinned cavities. The findings of the study showed that with an increase in cavity inclination, the magnitude of convective heat loss decreased in both finned and unfinned cavities, while the cavity surface temperature increased. At +90° inclination, the convective heat loss and Nusselt number were observed to have the lowest value, while the surface temperature had the highest value. For a downward‐facing cavity, the fins reduced convective heat loss, leading to an increase in cavity surface temperature. The finned cavity performed better for a vertically downward‐facing inclination (+90°) as it had a contribution of only 11% for convection heat loss compared with the unfinned cavity, which had a contribution of 21% for the same. Furthermore, an empirical model was developed based on the experimental results for the Nusselt number, which correlates experimental data with an error margin of ±15%. This model can be used to predict the Nusselt number for different inclination angles and surface heat flux levels. The presence of vertical fins in the cavity was found to be effective in reducing convective heat loss, especially for downward‐facing cavities. Understanding the influence of fin and cavity inclination on convective heat transfer can lead to enhanced efficiency and performance of solar receivers, thereby increasing the overall energy output of the system. [ABSTRACT FROM AUTHOR]

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]

This study introduces a novel hybrid solar–biomass cogeneration power plant that efficiently produces heat, electricity, carbon dioxide, and hydrogen using concentrated solar power and syngas from cotton stalk biomass. Detailed exergy-based thermodynamic, economic, and environmental analyses demonstrate that the optimized system achieves an exergy efficiency of 48.67% and an exergoeconomic factor of 80.65% and produces 51.5 MW of electricity, 23.3 MW of heat, and 8334.4 kg/h of hydrogen from 87,156.4 kg/h of biomass. The study explores four scenarios for green hydrogen production pathways, including chemical looping reforming and supercritical water gasification, highlighting significant improvements in levelized costs and the environmental impact compared with other solar-based hybrid systems. Systems 2 and 3 exhibit superior performance, with levelized costs of electricity (LCOE) of 49.2 USD/MWh and 55.4 USD/MWh and levelized costs of hydrogen (LCOH) of between 10.7 and 19.5 USD/MWh. The exergoenvironmental impact factor ranges from 66.2% to 73.9%, with an environmental impact rate of 5.4–7.1 Pts/MWh. Despite high irreversibility challenges, the integration of solar energy significantly enhances the system's exergoeconomic and exergoenvironmental performance, making it a promising alternative as fossil fuel reserves decline. To improve competitiveness, addressing process efficiency and cost reduction in solar concentrators and receivers is crucial. [ABSTRACT FROM AUTHOR]

Direct absorption solar collectors operating with nanofluids represent a promising technology in the field of solar thermal systems. However, the stability and the reliability of such fluids in real time operation is still an open issue, since their absorption performance has been mainly evaluated at lab-scale under stagnant conditions and their optical properties can be subject to degradation due to multiple reasons. A novel technique based on the combined use of pyranometers is here presented for measuring the absorption rate of nanofluids circulating in a volumetric solar receiver. In the present work, the absorption capability of a Single-Wall-Carbon-NanoHorns (SWCNHs) based nanofluid is experimentally investigated when varying temperature (between 25 °C and 45 °C) and mass flow rate (between 5 kg h−1 and 315 kg h−1). The optical efficiency of the nanofluid is found to be slightly affected by the temperature of the circulating fluid. The optical efficiency is checked for more than 80 hours of operation. [ABSTRACT FROM AUTHOR]

This study introduces the use of compressed air as a heat transfer fluid in small-scale, concentrated linear solar collector technology, evaluating its possible advantages over traditional fluids. This work assumes the adoption of readily available components for both linear parabolic trough and Fresnel collectors and the coupling of the solar field with Brayton cycles for power generation. The aim is to provide a theoretical analysis of the applicability of this novel solar plant configuration for small-scale electricity generation. Firstly, a lumped thermal model was developed in a MatLab® (v. 2023a) environment to assess the thermal performance of a PT collector with an evacuated receiver tube. This model was then modified to describe the performance of a Fresnel collector. The resulting optical–thermal model was validated through literature data and appears to provide realistic estimates of temperature distribution along the entire collector length, including both the receiver tube surface and the Fresnel collector's secondary concentrator. The analysis shows a high thermal efficiency for both Fresnel and parabolic collectors, with average values above 0.9 (in different wind conditions). Th5s study also shows that the glass covering of the Fresnel evacuated receiver, under the conditions considered (solar field outlet temperature: 550 °C), reaches significant temperatures (above 300 °C). Furthermore, due to the presence of the secondary reflector, the temperature difference between the upper and the lower part of the glass envelope can be very high, well above 100 °C in the final part of the collector string. Differently, in the case of PTs, this temperature difference is quite limited (below 30 °C). [ABSTRACT FROM AUTHOR]

The direct measurement of particle temperatures and advective losses from solid particle receiver has been a topic of necessary interest to de-risk the technology and improve its performance. Due to the flow's transient and stochastic nature, it has presented a challenge to traditional thermometry and metrology methods. In this work, a simplified quantitative non-intrusive imaging methodology previously developed is applied to Sandia's falling particle receiver during on-sun tests to collect image sets, which could help estimate the average particle temperature and particle egress rate from the system. Further additions to the technique are presented to permit the estimation of the plume (air and particles) egress rate and total advective heat losses during on-sun operation. The falling particle receiver testing campaign in 2020 and 2021 allowed the team to capture multiple flow configurations and environmental conditions used to build a large database of data captures with different characteristics. Finally, the results captured were used to complete a regression study to gain further insight into the factors which impact the particle egress and the receiver's efficiency. Particle temperature, receiver flow configuration, and wind speed were found to be the most impactful factors in the study. [ABSTRACT FROM AUTHOR]

High output temperature and photothermal conversion effectiveness were achieved with the absorber platform structure. A novel solar receiver was manufactured to integrate pre-heating and thermal conversion, aiming to enhance heat utilization and output temperature. This work is based on the engineering design and experimental testing of a solar cavity-receiver containing a porous copper foam that can volumetrically absorb high-flux radiation and heat up, through convection with air-flow. The air outlet temperature, outer wall temperature, thermal performance, and efficiency were experimentally determined by pore density, air mass-flow rate and solar irradiance. Additionally, the temperature growth of unit incident power, the unit volume efficiency growth rate, and output temperature were employed to evaluate the thermal conversion characteristics of the endothermic body (copper foam). The results indicated that the air outlet temperatures can reach 500 °C with lower input power. Furthermore, it was found that under a pore density of 30 pores per inch and a flow rate of 60 Lpm, the photothermal conversion efficiency of the absorber with copper foam reached as high as 87.61%, which is 35.04% significantly higher than that of an absorber without copper foam. The manageable solar receiver design proved to deliver a high-temperature air-flow (approximately 500 °C) with a reasonably high thermal efficiency (over 85%). [ABSTRACT FROM AUTHOR]

In this article, we designed an experimental system for underwater wireless optical communications. A function generation device sent frequencies (1–500 kHz) by amplitude shift key modulation technology, and these frequencies were loaded over light-emitting diode to propagate through a glass water tank with a length of 1 m, width of 40 cm, and height of 30 cm containing clean water of 80 L. These frequencies were received by a photodiode (BPX61), and the received signal was displayed through a digital storage oscilloscope device. Four techniques, single input–single output (SISO), single input–multiple output, multiple input–single output, and multiple input–multiple output (MIMO), were applied under the same optical conditions to know the quality of receiving the optical signal and the difference between them. Finally, the parameter values of signal-to-noise ratio, peak-to-peak voltage, and voltage gain were checked for each technique, and they were the lowest values for the SISO technique and the highest values for the MIMO technique. [ABSTRACT FROM AUTHOR]

Passive acoustic telemetry can be used within cooperative networks to track migratory species over great distances at a relatively low cost. However, the non‐uniform distribution of fixed receivers within networks often results in sporadic detection data.Here, we propose a novel combination of methods to measure the reliability of hot spot analysis results derived from track reconstructions of passive telemetry data. We use an iterative process to simulate tracks of animals, derive detection data from these tracks, and reconstruct tracks from these derived data using a movement model. We then compare quadrat count residuals from the simulated and reconstructed tracks for different grid resolutions. The methodological framework is outlined in detail and tested on the acoustic telemetry cooperative arrays off the US East Coast. Our methods are applied to a subset of blacktip shark, Carcharhinus limbatus, acoustic telemetry detection data collected off the US East Coast. We then apply the resultant quadrat count to a hot spot analysis to determine the distribution of animals derived from these track reconstruction methods. We integrate the results of our methods process with the hot spot analysis results to determine the reliability of this distribution information.The track reconstruction methods performed well in coastal regions, from Palm Beach County, FL to Long Island, NY, minimized the clustering effect of high densities of receivers, and closed the gaps in some regions that were lacking receiver coverage. This performance was primarily affected by the presence/absence of receivers, and to a lesser extent by receiver density and water depth, depending on the grid resolution.Our method combination demonstrates a means by which passive telemetry data can be regularized to determine the spatial distribution of animals across regions with non‐uniform sampling coverage. These methods also allow the user to determine the reliability of animal distribution products in a telemetry array and the factors that contribute to high accuracy and precision. Our iterative process enables managers to infer the reliability of ecological results in decision‐making processes and could be leveraged for use as a gap analysis to develop a national strategy for telemetry assets. [ABSTRACT FROM AUTHOR]

This article introduces a novel analytical equation for computing the Nusselt number within the macroporous structures of channel absorbers utilized in high-temperature solar receivers. The equation incorporates heat and mass transfer processes occurring within boundary layers as fluid flows through complex-shaped macroporous absorber channels. The importance of accounting for the length of the thermodynamic boundary layer within channel-type macroporous media when calculating heat transfer coefficients using the Nusselt equation is demonstrated. By incorporating proposed indicators of porosity and flow characteristics, this method significantly enhances the accuracy of heat transfer coefficient calculations for such media. Discrepancies observed in existing calculation relationships and experiments are attributed to the omission of certain proposed values in the Nusselt number for macroporous media. To address this, empirical coefficients for the Nusselt number are derived using statistical methods. The resulting semi-empirical equation is applied to macroporous absorbers in solar receivers. The findings enable more accurate predictions of future absorber characteristics, enhancing their efficiency. The derived equation is successfully validated against numerical data across various geometric structures of absorbers in concentrated solar power plants. [ABSTRACT FROM AUTHOR]

Objectives: Impeded diffusion fraction (IDF) is a novel and promising diffusion-weighted imaging (DWI) technique that allows for the detection of various diffusion compartments, including macromolecular coordinated water, free diffusion, perfusion, and cellular free water. This study aims to investigate the clinical potential of IDF-DWI in detecting microvascular invasion (MVI) in hepatocellular carcinoma (HCC). Methods: 66 patients were prospectively included. Metrics derived from IDF-DWI and the apparent diffusion coefficient (ADC) were calculated. Multivariate logistic regression was employed to identify clinical risk factors. Diagnostic performance was evaluated using the area under the receiver operating characteristics curve (AUC-ROC), the area under the precision-recall curve (AUC-PR), and the calibration error (cal-error). Additionally, a power analysis was conducted to determine the required sample size. Results: The results suggested a significantly higher fraction of impeded diffusion (FID) originating from IDF-DWI in MVI-positive HCCs (p < 0.001). Moreover, the ADC was found to be significantly lower in MVI-positive HCCs (p = 0.019). Independent risk factors of MVI included larger tumor size and elevated alpha-fetoprotein (AFP) levels. The nomogram model incorporating ADC, FID, tumor size, and AFP level yielded the highest diagnostic accuracy for MVI (AUC-PR = 0.804, AUC-ROC = 0.783, cal-error = 0.044), followed by FID (AUC-PR = 0.693, AUC-ROC = 0.760, cal-error = 0.060) and ADC (AUC-PR = 0.570, AUC-ROC = 0.651, cal-error = 0.164). Conclusion: IDF-DWI shows great potential in noninvasively, accurately, and preoperatively detecting MVI in HCC and may offer clinical benefits for prognostic prediction and determination of treatment strategy. [ABSTRACT FROM AUTHOR]

One of the problems in using PV cells to extract energy from sunlight is the temperature effect on PV cells. As the solar panel is heated, the conversion efficiency of light to electrical energy is diminished. Moreover, successive temperature elevations can cause dilatations in the array of cells which may also contribute to the degradation of the receiver. Some of the operating temperature mitigation approaches may include air-flow ventilation. In this study, data obtained by experimental and numerical simulations of a collector with bifacial PV cells is compared to the expressions found in the literature for the estimation of the heat transfer coefficient. Forced ventilation was applied to the studied collector as it accounts for much better heat dissipation. A new correlation for the estimation of the heat transfer coefficient is developed for such a geometry, for inlet velocities ranging between 3 and 8 m/s. Values of heat transfer coefficient estimated in the present work have been compared with studies of other researchers. [ABSTRACT FROM AUTHOR]

The outlet temperature targets for Gen 3 Concentrating Solar Power (CSP) systems pose a significant challenge to the structural reliability of high temperature metallic components, including those manufactured from nickel-based superalloys. Advanced ceramics present a potential solution due to their excellent high-temperature strength. However, accurate assessment of ceramic components requires an entirely different approach compared to metallic components. This paper describes the implementation of time-dependent reliability analysis of ceramic components in srlife – an open-source software package for estimating the life of high temperature CSP components. This new capability will allow high temperature CSP designers to make fair comparisons between competing metallic and ceramic designs and accurately assess the performance of different ceramic materials for CSP receivers and other components. The current version of the tool is available at https://github.com/Argonne-National-Laboratory/srlife.

In this paper, multi-objective optimization of the hydrogen production ( m ˙ H 2 ) of a solar-based cobalt-chlorine (Co–Cl) thermochemical cycle with grey relational analysis (GRA) has been performed. Monthly total irradiance averages (A), wind velocity (B), receiver height (C), receiver radius (D) and number of heliostats (E) are considered to achieve the highest the useful energy absorbed by the solar receiver ( Q ˙ a b s ), efficiency of the receiver (η r e c ), the overall efficiency of the system (η o v e r a l l) and hydrogen production ( m ˙ H 2 ). Orthogonal experimental design is planned according to L 18 orthogonal array created by Taguchi method. The percent contribution rates (PCR) on the Q ˙ a b s , η r e c , η o v e r a l l and m ˙ H 2 are determined with the help of ANOVA analysis. The optimal parameters are identified as monthly total irradiance average of 143.8 kW h (A 3), wind velocity of 5 m/s (B 2), receiver height of 8 m (C 1), receiver radius of 3 m (D 1) and number of heliostats of 850 (E 3), respectively. The highest Q ˙ a b s , η r e c , η o v e r a l l and m ˙ H 2 values corresponding to A 3 B 2 C 1 D 1 E 3 are obtained as 50.2 GW; 64.1%; 22.2% and 122.59 (tons/month), respectively. The PCR of the A, B, C, D and E parameters influencing the f-factor are determined to be 12.6 %, 1.92 %, 0.48 %, 15.03 %, and 53.20 %, respectively. Also, empirical equations are developed with regression analysis (RA) to estimate the Q ˙ a b s , η r e c , η o v e r a l l , m ˙ H 2 values. The statistical coefficients (R2-value) for training and testing data's are determined in the range of 0.771167–0.99608 for Q ˙ a b s , η r e c , η o v e r a l l and m ˙ H 2 , respectively. • Hydrogen production of a solar-based Co–Cl has been investigated. • Optimization of solar-based Co–Cl determined with Taguchi based GRA. • The η o v e r a l l of solar-based Co–Cl computed as 22.2%. [ABSTRACT FROM AUTHOR]

In a parabolic dish system, the heat losses from the cavity receiver significantly suppress the system's efficiency and may increase its overall cost. Several existing researches have numerically and experimentally developed the different cavity receiver models by modifying their inclinations, design geometrics, and structure. The conductive loss does not occur much in the cavity receivers compared to the convective loss. So, the analysis of convective loss is more critical in the cavity receivers; however, the accurate prediction of convection loss is quite complex due to the temperature distribution near the cavity. This prime aim of the paper is to comprehensively review the existing literature related to design configurations of cavity receivers and heat loss analysis to set a platform for performance improvement via design modifications. The study emphasizes the effect of geometric parameters like the structure of cavity receivers, shape and sizes, and angle of inclinations with the ground. Structural configurations, especially the hemispherical, cylindrical, conical, and trapezoidal cavity receivers utilized for the solar dish collector (SDC), are investigated between the years 1980 to 2022. A comparison is made based on heat loss models and research outcomes. Besides, the Nusselt correlation model used for predicting heat losses is also carried out in this review by varying the effects such as inclination, aperture ratio, wind effect, etc. This review supports the solar cavity designers for experimentally investigating and simulating a new modified solar cavity receiver with minimization and accurately predicting convective losses. [ABSTRACT FROM AUTHOR]

Photogrammetry is a valuable tool for 3D documentation, mapping, and monitoring of underwater environments. However, the ground control surveys necessary for georeferencing and validation of the reconstructed bathymetry are difficult and time consuming to perform underwater, and thus impractical to scale to larger areas. Underwater direct georeferencing, using a differential GNSS receiver synchronized with an underwater camera system, offers an attractive alternative to surveying underwater ground control points in conditions when the seafloor is clearly visible from the surface. In this paper, the design of an underwater direct georeferencing system using mostly commercial off the shelf components is presented. The accuracy of the system is evaluated against geodetic survey based on trilateration and leveling, as well as by RTK (real time kinematic) positioning using a tilt-compensated GNSS receiver mounted on an extended pole to allow measurements of points in up to 7 m in water depth. Tests were conducted in a controlled outdoor pool setting with depths from 1–3 m, as well as in a 10 m × 10 m test plot established on the seafloor in a near-shore environment by Catalina Island, California at depths from 4–10 m. Comparing the geometry of the photogrammetric reconstruction with the geodetic survey yielded sub centimeter consistency, and 1 mm accuracy in length measurement was achieved when compared with calibrated 0.5 m scale bars. Through repeated surveys of the same area, repeatability of georeferencing is demonstrated within expectations for differential GNSS positioning, with horizontal errors at sub centimeter level, and vertical errors of up to 3 cm in the worst cases. These tests demonstrate the benefits of the underwater direct georeferencing approach in shallow waters, which can be scaled up much more easily than measuring underwater ground control points with traditional approaches, making this an ideal option for collecting accurate bathymetry of the seafloor over large coastal areas with clear waters. [ABSTRACT FROM AUTHOR]

Communication presents a critical challenge for emerging intermittently powered batteryless sensors. Batteryless devices that operate entirely on harvested energy often experience frequent, unpredictable power outages and have trouble keeping time accurately. Consequently, effective communication using today's low-power wireless network standards and protocols becomes difficult, particularly because existing standards are usually designed to support reliably powered devices with predictable node availability and accurate timekeeping capabilities for connection and congestion management. In this article, we present Greentooth, a robust and energy-efficient wireless communication protocol for intermittently powered sensor networks. It enables reliable communication between a receiver and multiple batteryless sensors using Time Division Multiple Access–style scheduling and low-power wake-up radios for synchronization. Greentooth employs lightweight and energy-efficient connections that are resilient to transient power outages, while significantly improving network reliability, throughput, and energy efficiency of both the battery-free sensor nodes and the receiver—which could be untethered and energy constrained. We evaluate Greentooth using a custom-built batteryless sensor prototype on synthetic and real-world energy traces recorded from different locations in a garden across different times of the day. Results show that Greentooth achieves 73% and 283% more throughput compared to Asynchronous Wake-up on Demand MAC and Receiver-Initiated Consecutive Packet Transmission Wake-up Radios, respectively, under intermittent ambient solar energy and over 2× longer receiver lifetime. [ABSTRACT FROM AUTHOR]

The development of a new generation of solid particle solar receivers (SPSRs) with high solar absorptivity (0.28–2.5 μm) and high infrared emissivity (1–22 μm) is crucial and has attracted much attention for the attainment of the goals of "peak carbon" and "carbon neutrality". To achieve the modulation of infrared emission and solar absorptivity, two types of medium- and high-entropy rare-earth hexaboride (ME/HEREB6) ceramics, (La0.25Sm0.25Ce0.25Eu0.25)B6 (MEREB6) and (La0.2Sm0.2Ce0.2Eu0.2Ba0.2)B6 (HEREB6), with severe lattice distortions were synthesized using a high-temperature solid-phase method. Compared to single-phase lanthanum hexaboride (LaB6), HEREB6 ceramics show an increase in solar absorptivity from 54.06% to 87.75% in the range of 0.28–2.5 μm and an increase in infrared emissivity from 76.19% to 89.96% in the 1–22 μm wavelength range. On the one hand, decreasing the free electron concentration and the plasma frequency reduces the reflection and ultimately increases the solar absorptivity. On the other hand, the lattice distortion induces changes in the B–B bond length, leading to significant changes in the Raman scattering spectrum, which affects the damping constant and ultimately increases the infrared emissivity. In conclusion, the multicomponent design can effectively improve the solar energy absorption and heat transfer capacity of ME/HEREB6, thus providing a new avenue for the development of solid particles. [ABSTRACT FROM AUTHOR]

This paper is a summary of the last ten years of work on the study of parabolic trough collectors (PTCs) and compound parabolic collectors (CPCs) coupled to photovoltaic and thermal solar receiver collectors (SCR-PVTs). While reviewing the state of the art, numerous review papers were found that focused on conventional solar receiver collector (SRC) technology for solar thermal generation. However, there is a lack of review papers summarizing SRC-PVT hybrid technology for solar electric/thermal generation, which would be beneficial for researchers interested in this area of research. This paper provides a review of SRC-PVT hybrid technologies. The theoretical foundations for analyzing and modeling PTC and CPC concentrators coupled to SRC-PVT are described, with an emphasis on modeling through thermal resistances and energy balances. Additionally, this section provides a concise overview of previous studies that have addressed the modeling of PTC and CPC collectors coupled to SCR-PVT, as well as experimental information useful for the validation of new mathematical models of SRC-PVT. [ABSTRACT FROM AUTHOR]

A suggested absorption tube was designed for a thermosyphon solar water heating system (TSWHS) to enhanced the ability of the solar receiver to capture solar energy. The proposed design was based on overlapping and reversed flows, and its correctness was confirmed by conducting experimental simulations of the incident solar radiation and projecting heat flux on the proposed receiver tube models (Rt). Five receiver tube models were proposed as the standard, designed, and manufactured models which were tested under constant boundary conditions for all modeled flow rates (100, 150, 200, and 250 mL), flow directions (px and py), and constant heat flux. The most favorable thermal enhancement outcomes were achieved with the Rt4 model that exhibited a thermal efficiency of 70.5%, featuring an inner tube diameter of 12 mm and outer tube diameter of 35 mm, incorporating a py flow path. The selected model (Rt4) was employed, utilizing a py flow path for manufacturing the flat-plate collector (SRT2). The model was then compared with a normal model (SRT1) through Tests that were conducted for each model under similar weather conditions. The thermal gradient within the horizontal tank displayed an improvement by increasing 17% in heat transfer compared with the normal model. [ABSTRACT FROM AUTHOR]

Parabolic trough collectors (PTCs) play a vital role in solar-thermal energy conversion, with the absorber tube being central to heat collection efficiency. This study investigates the potential for improving heat transfer within the PTC absorber tube using Fiberfrax 140 coated with Al2O3 as a novel reflector material. The research is driven by the ongoing pursuit of enhanced PTC performance. A standard modeling approach was employed, utilizing Computational Fluid Dynamics (CFD) analysis with SolidWorks Flow Simulation software, coupled with solar simulations to assess collector performance under varying conditions. Environmental parameters of Bauchi such as temperature, humidity, and wind speed were sourced from the Nigerian Meteorological Agency (NiMet). Optimization techniques were implemented to establish the optimal design configuration. The optimal design parameters were determined as a focal length of 700mm and a rim angle of 90°. Simulations were conducted daily from 8:00 AM to 5:00 PM, encompassing the period of January to June. A mass flow rate of 0.2 kg/s, informed by existing literature, was employed in the simulations. The results indicate improved collector performance throughout the simulated period, with peak thermal efficiency ranging from 70% to 82%. [ABSTRACT FROM AUTHOR]

Thermal efficiency serves as a crucial indicator of performance, facilitating the prediction of the overarching functionality of large-scale systems through the analysis of parabolic trough behavior in relation to the working fluid's temperature. This study examines the influence of heat loss on the efficiency of collectors, employing a numerical simulation to distribute the tube's thermal efficiency across the four distinct seasons. A comprehensive heat transfer model for the thermal analysis of parabolic trough solar receivers has been developed, considering significant variables such as solar intensity, the flow rate of heat transfer, and heat losses. This research endeavors to evaluate the performance of a specifically designed 24-metre parabolic trough solar collector (PTSC) under Cairo's climatic conditions, focusing on surface temperatures and thermal efficiency. The system was numerically analysed during winter, from January 15 to January 21, highlighting efficiency metrics across the week at a mass flow rate of 1.41 kg/s, where efficiency did not surpass 35% on the concluding day. The proposed model incorporates precise heat transfer correlations and an in-depth examination of radiative heat transfer, aiming to underpin the foundation for the manufacture of larger units within Egypt. The results indicate that thermal efficiency is critically impacted by heat loss, underscoring the necessity for refined models that accurately represent heat transfer dynamics within parabolic trough solar collectors. [ABSTRACT FROM AUTHOR]

Energy transformation requires replacing power plants based on fossil raw materials with renewable energy. Energy harvesting plays an important, although not fully appreciated, role here. Distributed, local power supply systems for small receivers, based on various sources which previously dissipated energy, may contribute to changing the current energy paradigm. This article presents an overview of energy harvesting technologies and various energy sources used in this process. Particular attention was paid to sources of a less conventional nature. The aim of this article is to encourage and direct scientists with the potential to explore this topic to look for new, previously unexploited energy sources and innovative and effective methods of obtaining useful energy in the harvesting process. [ABSTRACT FROM AUTHOR]

Significant high-quality heat is wasted in the vacuum thermionic generator (VTIG), which can be efficiently utilized as a prime mover of a bottoming system for cogeneration applications. For this purpose, a new environmental-friendly hybrid system composed of a heliostat solar field, VTIG, and looped multi-stage thermoacoustically driven cryocooler (LMTC) is established, in which the high-temperature heat source of the solar receiver runs the VTIG to generate power, and the LMTC recovers the waste heat of the VTIG to produce a cooling load. Thermodynamic, economic, and environmental analyses of the system are carried out based on exergy and emergy concepts. Moreover, a parametric study is performed to assess the effect of design parameters on the system's thermodynamic, economic, and environmental criteria. Finally, the multi-criteria salp swarm optimization algorithm and decision-making procedures are conducted to improve the exergetic performance and decrease the system's cost and monetary emergy rates along with the environmental impact and ecological emergy rate. Findings depict that at the reliable, optimal operation of the system, the exergetic efficiency can reach 29.36% with a maximum power of 17.2 MW and cooling load of 0.260 MW. The system's cost and monetary emergy rate can be reduced to 0.059 $/s and 5.94 × 1010 seJ/s, with 10.6% and 10% reductions, respectively. Moreover, the environmental impact and ecological emergy rates decline by 6% and 7.4%, respectively. The theoretical findings may offer guidance for the optimum designing and practical running of such a solar solid-state cogeneration system. [ABSTRACT FROM AUTHOR]

Anadromous salmonid species vary in their use of open ocean, coastal, and inland marine waters. To better understand this diversity in behavior and habitat use, 120 coastal cutthroat trout, Oncorhynchus clarkii clarkii, were caught in southern Puget Sound, Washington, USA, tagged with acoustic transmitters, and 95 were detected by a network of receiver stations. Despite sufficient time to reach other parts of the Salish Sea where many receivers operated, none was detected beyond southern Puget Sound, indicating localized movements. Within southern Puget Sound, fish were detected at 34 of 127 receivers in marine sites throughout the year but especially in spring and fall. Most detection events (between first and last detections at a given receiver) were brief (60.5% were ≤ 2 h and 76.8% ≤ 6 h), indicating movement along the shoreline. However, 823 events (12.8%) exceeded 12 h and 222 (3.4%) exceeded 24 h at a receiver, indicating longer occupancy at certain sites and by certain individuals. The detections also indicated that cutthroat trout were active throughout the 24-h period, but they moved more often at night and less often in other periods than would occur by chance, and they moved more often on ebbing and flooding tides and less often at slack periods. Fish with pressure-sensitive transmitters were almost always (97.3% of records) within 2.5 m of the surface and 76.8% between 1 – 2 m, despite deeper and shallower waters nearby where they could have been detected. The data provide new insights into the behavior of this species, whose marine ecology has not been extensively studied, and differs markedly from the region's other native salmonids. [ABSTRACT FROM AUTHOR]

As a consequence of the limited availability of fossil fuels, green energy is gaining more and more popularity. Home and business electricity is currently limited to solar thermal energy. Essential receivers in current solar thermal power plants can endure high temperatures. This ensures funding for green thermal power generation. Regular solar thermal power plant testing is arduous and time-consuming. They need expensive installation and take up much space. Many free software and tools can model and simulate solar thermal-producing systems. Some techniques can evaluate and predict the plant's performance, while others can investigate specific components. Nothing using research tools has ever reached the top. Simulated testing may precede power plant construction. This research requires basic visual help. A rudimentary plant model was developed when the computational calculations for thermal performance were obtained. Plus, it may estimate how much power the facility would produce. The program includes hydraulic heat transport fluids, ambient factors, a database, and user input parameters. Free hourly weather data from anywhere is available from the simulator. The simulator calculates the thermal power delivered by each component while running constituent simulators. [ABSTRACT FROM AUTHOR]

The energy sector is the main source of greenhouse gases, so it has the highest potential for improvement. The improvements can be achieved by generating energy from renewable sources. It is necessary to combine production from renewable sources with storage systems. Thermal energy storage using concentrated solar power systems is a promising technology for dispatchable renewable energy that can guarantee a stable energy supply even in remote areas without contributing to greenhouse gas emissions during operation. However, it must be emphasised that greenhouse gases and other impacts can occur during the production process of concentrating solar system components. This paper analyses the receiver design to produce thermal energy for the existing CSP dish plant at the Energy Center of the Politecnico di Torino. The plant is designed to produce electrical energy in the spring and summer periods. In addition to this energy production, the CSP can be adopted to produce thermal energy, through hot water, during the less favourable periods of the year in terms of global solar radiation. The surface heat flux is calculated in the first part of the analysis to obtain the maximum internal temperature in the receiver, which is 873.7 °C. This value is a constraint for the choice of material for the solar receiver. A life cycle assessment is performed to compare the emissions generated during the production of the main components of the CSP system with the emissions generated by the methane-fuelled water heater to produce the same amount of thermal energy. It can be concluded that the production of the main components of the CSP system results in lower greenhouse gas emissions than the operational phase of a conventional system. Given the assumptions made, the utilization of methane leads to the emission of approximately 12,240 kg of CO2, whereas the production of the CSP system results in emissions totalling 5332.8 kg of CO2 equivalent [ABSTRACT FROM AUTHOR]

This study examined the performance of a concentrating solar collector with an asymmetric reflector. Two receivers were investigated, differing in the presence of photovoltaic cells. The first one was equipped with cells on both sides while the other was without cells. The analysis was performed using a numerical model that integrates a combination of three-dimensional optical and thermal analyses developed in COMSOL. The investigation included studying the influence of CuO/water and CuO/Syltherm 800 nanofluids on the thermal performance for the receiver without photovoltaic elements, as well as on both thermal and electrical efficiencies for the hybrid receiver. Two volumetric concentrations of CuO in water and Syltherm 800, 3% and 5%, were explored with varying inlet temperatures, ranging from 20 °C to 80 °C for the hybrid solar unit and from 20 °C to 140 °C for the thermal solar unit. The outcomes of the examination were compared between the nanofluids and the pure base fluid. Properly pressurized water was considered in the case without photovoltaic elements. [ABSTRACT FROM AUTHOR]

This paper presents a detailed analysis of the optical performance of circular trough concentrators with tubular receivers. First, a simple analytical formula for the achievable geometric concentration ratio as a function of the rim angle and acceptance angle is developed. Notably, the development reveals the existence of three distinct concentration ratio regimes: a first regime where the receiver is sized based on the reflection of the edge rays from the rim alone, a second regime where the receiver is sized based on the rim and the edge ray caustics, and a third regime where two reflections from the mirror are permitted. Several exemplary designs are proposed and further analyzed using Monte Carlo ray tracing to obtain transmission angle curves and receiver flux distributions. For an acceptance angle of 1 deg, the circular trough concentrator with circular receiver is found to achieve a maximum geometric concentration ratio of 7.695× with a peak flux of 30 suns. For large acceptance angles (10 deg), the circular trough achieves a geometric concentration ratio as high as 82% of that of a parabolic trough. This noteworthy performance, along with the fact that a circular mirror is amenable to an inflated polymer construction, makes this configuration promising for low-cost, low-concentration solar thermal applications. [ABSTRACT FROM AUTHOR]

Low visibility events at King Khalid airport in Riyadh, Saudi Arabia, are investigated using hourly time series of meteorological and air pollution data from April 2015 to December 2017. The analysis of binary classification is based on two machine learning classifiers (random forest (RF) and K-nearest neighbors (KNN)). Six models based on the feature selection methods of RF feature importance and Pearson correlation matrix are presented. The classification tasks include two resampling approaches (random oversampling and random undersampling) to address the problem of an imbalanced dataset of the visibility event classes. An important finding is that oversampling outperforms undersampling for the evaluated classifiers and achieves higher scores in terms of accuracy and F1 score metrics. The RF classifier has a better performance compared to the KNN in both sampling approaches. The RF classifier with oversampling approach provides the best overall performance in terms of accuracy, F1 score, and area under the receiver operating characteristics (AUROC). The best model has scores above 0.95 based on all the evaluation metrics considered in the study. Air temperature and dewpoint temperature have minimal impact on the performance, whereas the particulate matter with aerodynamic diameter <10 μm (PM10) has a profound impact on the performance. It is found that the PM10 has the highest importance (52%) for the low visibility events based on the analysis of RF feature importance. Other pollutants and meteorological variables show relative importance between 5 and 10% for low visibility events. Overall, the best model is found when all variables, except temperature and dewpoint temperature, are employed to predict the visibility classes. [ABSTRACT FROM AUTHOR]

Geological structures have been shown by studies to have influence on the occurrence, storage and transportation of groundwater. Understanding the structural network of an area unearths a deep insight into the groundwater dynamics of the area. A geological structural analysis was carried out to reveal the geological structural network of Ghana's Voltaian basin. Using aeromagnetic data, structural density models were generated using the Center for Exploration Targeting grid analysis technique for two depth ranges (that is up to 100 m and 300 m) over the Voltaian basin. The total length of geological structures (lineaments) delineated at depths up to 100 m and 300 m were more than 5000 km and more than 8000 km, respectively. Given this, the study area was observed to be structurally dense at each of the aforementioned depths. The structural density models were discretized into five classes (very low, low, moderate, moderately high and very high regions), each of which was evaluated to determine their spatial association with known locations of groundwater occurrences within the study area using the frequency ratio technique. Frequency ratio results for both structural density models derived at 100 m and 300 m depths show the existence of a strong correlation between high structural density model classes and the known groundwater occurrences. The structural density models were further evaluated using the receiver operating characteristics curve. The area under the receiver operating characteristics curve scores indicates that, although both structural density models showed very good performance (with receiver operating characteristics scores greater than 0.7), the 300‐m depth structural density model performed better than the structural density model generated at a depth of 100 m (with their receiver operating characteristics scores being 0.721 and 0.715, respectively). The obtained results corroborate with literature assertion that groundwater occurrence within the Voltaian basin is mainly associated with structural features. It is expected that the outputs of this study would guide future groundwater exploration programmes within the study area. [ABSTRACT FROM AUTHOR]

In the context of clean energy and green cryptocurrency development, the relationship between energy and cryptocurrency markets deserves further exploration. This study employs a quantile time-frequency connectedness approach to measure the dynamic connectedness and volatility propagation mechanisms between oil, clean energy, green cryptocurrency (GC), and non-green cryptocurrency (NGC) markets. Our findings suggest that, at median and low volatility levels, the oil and clean energy markets act as net receivers, taking on volatility spillovers from cryptocurrency markets. However, at high volatility levels, oil and clean energy markets transform into net transmitters. Most NGCs are volatility transmitters, while most GCs are volatility receivers in the median and extremely high volatility cases. We also observe that the total connectedness index (TCI) is heterogeneous over time and dependent on economic events. At median and low volatility levels, the short-run TCI makes the primary contribution. On the other hand, for high volatility levels, where short-term TCI does not have an absolute advantage, long-term TCI plays a greater role in many periods. Additionally, there is asymmetry in the TCI (including long-term and short-term TCI) at the quantile level. In the median and extreme scenarios, the COVID-19 has caused different levels of shock on oil, clean energy, GC, and NGC markets connectedness. [ABSTRACT FROM AUTHOR]

The central tower solar receiver system is comprised of a number of small tracing mirrors that focus the beam radiation onto a huge tower in the centre. The tracing mirrors are placed as well as adjusted in such a manner that the light is always reflected at the top of the tower. The major goal of this study is to carry out a mathematical assessment of the central tower solar receiver where solar load calculation and heat transfer analysis has been carried out. Solar load is calculated for the location of Pune, India. Mathematical modelling is performed for the solar central receiver system Results of the mathematical modelling reveal that the estimated average sunshine hour for the year ranges from 10.9 hours in the month of December to 12.9 hours in the month of July. The maximum incident beam radiation of 1050.9 w/m2 has been estimated in the month of April at 1200 hour. After computing the variables, the matrix equation can be generated and the system can calculate the energy under the first-order differential equation. The system's thermal efficiency can be computed once the maximum temperature of the heat transfer fluid, ambient air as well as copper tube is known. [ABSTRACT FROM AUTHOR]

The problem of recovering water from treated wastewater may concern an increasing number of countries, especially those with low water resources. After costly treatment processes, water taken from surface and underground intakes is used and then largely discharged to receivers in the form of treated wastewater. Advanced wastewater treatment methods ensure that the treated wastewater is characterized by very low physical and chemical pollution, sometimes better than the water quality in the receiving basin. The research was conducted under a cooperation agreement between Bialystok University of Technology and Bialystok Waterworks Ltd. The recovery of water from wastewater was one of the topics pursued. This paper analyzes the parameters of treated wastewater from the largest municipal wastewater treatment plant in the Podlaskie Province. The analysis of the treated wastewater composition was based on monitoring studies conducted by the company Bialystok Waterworks Ltd. between 2020 and 2023. The analysis concerned the basic parameters of wastewater, namely the content of organic matter and total suspended solids. This was due to the requirements for the recyclability of treated wastewater. Linear modeling was performed to determine if a sufficiently strong correlation was detected;otherwise output distribution characteristics were provided.In all cases, the output concentrations were far below the class A limits for irrigation in the whole research period. [ABSTRACT FROM AUTHOR]

Hydropower facilities are often remotely monitored or controlled from a centralized remote control room. Additionally, major component manufacturers monitor the performance of installed components, increasingly via public communication infrastructures. While these communications enable efficiencies and increased reliability, they also expand the cyber-attack surface. Communications may use the internet to remote control a facility's control systems, or it may involve sending control commands over a network from a control room to a machine. The content could be encrypted and decrypted using a public key to protect the communicated information. These cryptographic encoding and decoding schemes become vulnerable as more advances are made in computer technologies, such as quantum computing. In contrast, quantum key distribution (QKD) and other quantum cryptographic protocols are not based upon a computational problem, and offer an alternative to symmetric cryptography in some scenarios. Although the underlying mechanism of quantum cryptogrpahic protocols such as QKD ensure that any attempt by an adversary to observe the quantum part of the protocol will result in a detectable signature as an increased error rate, potentially even preventing key generation, it serves as a warning for further investigation. In QKD, when the error rate is low enough and enough photons have been detected, a shared private key can be generated known only to the sender and receiver. We describe how this novel technology and its several modalities could benefit the critical infrastructures of dams or hydropower facilities. The presented discussions may be viewed as a precursor to a quantum cybersecurity roadmap for the identification of relevant threats and mitigation. [ABSTRACT FROM AUTHOR]

Evaluating the heat losses of linear Fresnel concentrator (LFC) receivers is crucial for determining plant efficiency and managing the flow rate in solar lines. This becomes particularly significant when operating in direct steam generation to manage the steam quality at the line outlet. In general, the LFC receiver heat losses are determined experimentally on prototype systems to control the inlet condition or numerically using 3D computational fluid dynamics models or 1D mathematical models. The originality of this work is in reporting the study of heat losses of a commercial 9 MWe solar Fresnel power plant without impacting its electricity production. The experimentally measured receiver's linear heat losses were found to be well represented by a second-degree polynomial function of the difference between the inlet/outlet fluid temperature average and the ambient temperature. Finally, to express the strong influence of wind speed on the receiver heat losses, a 1D single-phase model was developed and adapted to include the current receiver degradation. To conclude, the model was validated by comparing the experimental and theoretical results. Based on this comparison, it can be concluded that the model accurately predicts experimental heat losses with an acceptable uncertainty of ±30%, regardless of the wind velocity. [ABSTRACT FROM AUTHOR]

The solar power tower (central receiver power plant) as one type of concentrated solar thermal power systems can be used to generate electricity in a way similar to the thermal power plants and so, numerous large-scale central receiver power plants have been constructed and connected to the bulk power system to transfer their generated power to the power network. The variation in solar radiation leads the generated power of these power plants to change, too. Thus, the integration of these large-scale solar power towers into the power system results in some challenges that must be addressed. To study the effect of solar power towers on the power system, new techniques must be developed to consider the uncertain nature of these plants. For this purpose, in this paper, to investigate the impact of central receiver power plants on the operation studies of the power system, the well-being approach is proposed. To consider the solar power towers in the operation studies of the power system, a multistate model is developed for these plants that both variations in the generated power and failure of composed components are taken into account. To evaluate the effectiveness of the proposed technique, the well-being models of two reliability test systems including RBTS and IEEE-RTS are determined and the effect of the central receiver power plant on the operation indices such as health state probability, risk, spinning reserve, peak load carrying capability and increase in peak load carrying capability is investigated. [ABSTRACT FROM AUTHOR]