Search Results (196)

This study analyzes the impact of thermal and electrical storage solutions coupled with Photovoltaic (PV) and Concentrating Solar Power (CSP) plants, proposing an innovative model to test a Hybrid Energy Storage System (HESS). The work presents an innovative Mixed Integer Linear Programming (MILP) model to determine the optimal configuration and operational strategy of a HESS within a grid-connected Microgrid (MG). The research focuses on the synergistic integration of PV with Lithium-ion Electrical Energy Storage (EES) and CSP with Thermal Energy Storage (TES). The MG includes dynamic residential, commercial, and hospital loads. The MILP model is optimized over a 24 h horizon across four season-representative days, utilizing a multi-criteria objective function that balances economic performance and CO₂ emissions via a weighting factor ω ∈ [⁰,¹]. Three distinct CSP options such as Parabolic Trough Collectors with varying Heat Transfer Fluids (molten salt or thermal oil) and TES types (direct and indirect dual-tank, or Phase Change Material) are analyzed, each coupled with a Rankine or Organic Rankine Cycle. Key constraints address energy balances, component efficiencies, power limits, and storage dynamics. The comprehensive results identify the most suitable technology portfolio mix and optimal hour-by-hour operational rules, providing transparent decision-making criteria based on storage size, process temperatures, and specific demand profiles. Full article

This study experimentally evaluates the thermal performance of a compact parabolic trough solar collector (PTSC) operating under actual solar conditions in Chachapoyas, a high-Andean city in northern Peru characterized by frequent cloud cover and variable irradiance. Despite the growing interest in solar thermal systems, few studies have assessed PTC behavior under high-altitude, diffuse radiation conditions typical of Andean regions. The PTSC, aligned along the north–south axis and equipped with a manual solar tracking system, was monitored for 30 consecutive days. Solar irradiance, ambient temperature, and water inlet/outlet temperatures were recorded at 30 min intervals using a DAVIS Vantage Pro Plus weather station and infrared thermometers (±0.5 °C accuracy). Thermal efficiency was determined from the ratio of useful heat gain to incident solar energy, based on instantaneous irradiance data. Results showed peak irradiance values of 1000 W m⁻² and maximum outlet water temperatures of 85 °C, achieving an average efficiency of 68 ± 2.5%. The collector maintained stable operation even under fluctuating radiation, confirming its suitability for domestic hot-water and low-temperature industrial applications. These findings provide the first experimental evidence of efficient solar-thermal conversion in cloudy highland environments of Peru, supporting the deployment of decentralized renewable energy systems in the Andean region. Full article

Parabolic trough collectors (PTCs) are highly sensitive to receiver positioning accuracy; however, most existing studies report optical efficiency degradation without formally defining alignment tolerance limits. This study proposes a tolerance-based thermo-optical risk framework to quantify allowable receiver misalignment envelopes for reliable PTC operation. A Monte Carlo Ray Tracing (MCRT) methodology is employed to evaluate the impact of angular receiver misalignment on optical efficiency and circumferential heat flux redistribution. Beyond conventional efficiency metrics, normalized flux-based thermal non-uniformity indicators are introduced to assess thermo-mechanical risk without requiring full thermo-fluid modeling. The results reveal a nonlinear decoupling between optical acceptability and thermal safety. While optical efficiency remains above 0.80 up to approximately ±6°, pronounced flux localization and rapid growth of thermal stress indicators occur beyond ±4°, marking the onset of thermally critical behavior. The identified ±4° threshold corresponds to approximately twice the collector half-acceptance angle (θ_(crit)/δ ≈ 2), demonstrating geometry-dependent scaling characteristics. The proposed framework formalizes the optical–thermal decoupling phenomenon and transforms conventional efficiency-based evaluation into a reliability-informed alignment tolerance assessment tool applicable to manufacturing precision, installation control, and operational quality management in CSP systems. Full article

Pharmaceutical industries require a continuous heat supply to sustain around-the-clock operations such as sterilization. While fossil-fuel systems ensure reliability, they increase emissions and fuel dependence. Integrating a small-scale parabolic trough collector (PTC) with concrete thermal energy storage (C-TES) enables continuous and stable solar heat delivery, offering a flexible solution for pharmaceutical manufacturing. This study investigates the integration of PTC and C-TES to provide continuous heat supply using 12 representative days of the year based on weather data for Makkah City obtained from the Renewable Resource Atlas (RRA) developed by the King Abdullah City for Atomic and Renewable Energy (K.A.CARE). Model validation was performed using experimental PTC–C-TES charging data and a simplified C-TES module model. The results show that the C-TES system successfully maintained operating temperatures between 120 °C and 310 °C. Demand coverage was identified as a key design parameter. Full demand coverage requires approximately 73 PTC units and 1600 C-TES modules, representing increases of about 4.5 and 5 times compared with the 25% coverage case. Techno-economic analysis indicates that the levelized cost of heat (LCOH) reaches an optimum of approximately 89.7 USD/MWh at 25% coverage, while overall efficiency peaks at about 41%. The results indicate that a moderate solar contribution of around 25% provides the optimal balance between cost and operational flexibility. Full article

This paper presents a transient performance comparison of a flat-plate solar collector (FPSC) and a sun-tracked parabolic trough collector (PTC) with a double U-tube receiver. Both collectors were modeled using in-house transient mathematical models and validated against experimental data obtained from a dedicated test stand. After validation, annual simulations were conducted for Kraków, Poland, using hourly meteorological data from the PVGIS database. The analysis focused on the long-term thermal and economic performance of both collector types under identical boundary conditions. The electricity demand of the tracking system was included using a constant motor power assumption. A simplified techno-economic evaluation was performed using the Levelized Cost of Heat (LCOH), accounting for investment costs, operating and maintenance expenses, auxiliary electricity consumption, system degradation, and cost escalation over a 20-year lifetime. For a comparable aperture area, the calculated LCOH amounted to 0.096 EUR/kWh for the sun-tracked PTC and 0.041 EUR/kWh for the stationary FPSC. The results indicate that, despite higher thermal performance, the examined PTC configuration is not economically competitive for low-temperature heat production under the assumed cost structure, mainly due to its higher investment cost. Full article

This study proposes a novel redesign of a solar water heater prototype by integrating a stationary compound parabolic concentrator (CPC) internally within a standard collector housing. Unlike conventional flat-plate systems or external trough collectors, this design aims to enhance thermal efficiency while maintaining a compact footprint suitable for residential retrofitting in tropical climates. The system’s thermal performance was analyzed using a 3D finite element method (FEM) based on the convection-diffusion equation, with a specific focus on a 2 cm focal length configuration designed to fit spatial constraints. The simulation results indicated a maximum water temperature of 62.9 °C under concentrated solar flux, while the experimental prototype achieved a maximum temperature of 55.0 °C under corresponding field conditions. The comparative analysis reveals a temperature discrepancy of approximately 8 °C (12.5%), which is attributed to the simplified boundary conditions neglecting radiative losses in the model. Despite this deviation, the proposed parabolic design demonstrated a distinct thermal enhancement compared to the conventional baseline. These findings validate the technical feasibility of the compact internal concentrator, offering a low-cost, high-performance alternative for domestic water heating applications. Full article

Direct steam generation in parabolic trough collectors presents challenges due to the non-uniform distribution of heat flux and the appearance of flow patterns. These conditions can induce stresses, deformations, and deflections that compromise the structural integrity of the absorber tube; therefore, this study developed a coupled numerical model (optical, thermohydraulic, thermal, and thermoelastic) capable of reproducing the absorber tube’s behavior under real operating conditions. The methodology includes the following: (i) an optical model using Monte Carlo ray tracing to obtain the non-uniform distribution of solar heat flux and the local concentration ratio; (ii) a two-fluid thermohydraulic model to describe the transition from subcooled liquid to superheated vapor; (iii) a thermal conduction model; and (iv) an analytical thermoelastic model to quantify stresses, deformations, and deflections. The results identify the region near 421.35 m as the most critical, where circumferential temperature differences reached 28.38 K, generating maximum deformations between 600 and 800 με and deflections up to 18 mm along a 25 m section, 1 mm about to touch the glass cover. These findings demonstrate that this model facilitates the identification of critical conditions and the assessment of structural risks, contributing to improved reliability and safety in parabolic trough solar thermal power plants. Full article

A parabolic trough collector (PTC) is a linear concentrating system consisting of a parabolic-shaped reflector with a receiver tube positioned along the focal axis. In this study, the performance of a parabolic trough solar collector is evaluated, with aperture area, collector length, breadth, Rim angle, and inner and outer absorber diameters of 5.54 m², 3.65 m, 1.52 m, 70°, 0.048 m, and 0.05 m, respectively. The experiment was conducted at Ranchi, India (23.35° N and 85.30° E). During this day, marked by a cloudless sky, the ambient temperature ranged from 27 °C to 39 °C. The global solar radiation ranged from (630 W/m² to 975 W/m²), and the wind speed varied between (0.8 m/s and 1 m/s). Aluminium oxide (Al₂O₃) and Therminol VP-1-based nanofluid were employed as the working fluid. The different volume fractions of nanoparticles were taken, and the evacuated tube PTC performance was analysed. When Al₂O₃–Therminol VP-1 of varying concentration (0–4%) and mass flow rate of 0.041 kg/sec is used, it has been observed that the receiver’s heat transfer performance improved with an increment in nanoparticle volume fraction. Temperature-dependent properties were applied to the thermal efficiency, exhibiting a notable increase of approximately 7.2% when the volume fraction ascends from 0 to 4%. At elevated Reynolds numbers, the efficiency decreases compared to lower volume fractions. These results contribute to understanding the effect of nanoparticle concentration on PTC performance. Full article

Recent advances in design, manufacturing and development techniques have been very relevant to making solar collectors feasible for production in a variety of applications. In the field of concentrated solar thermal technologies, several techniques have been developed to achieve high levels of radiation concentration. The generation of concave curvature geometry through the polishing of the reflective surface or through specialized machining is one of the most common methods. However, the way in which these bends are obtained can vary significantly, depending on the required quality of optical concentration for the application. This study presents a simple parametric technique to achieve a parabolic curvature for solar concentration applications. To do this, a controlled bending deformation was applied to a metal hollow profile beam supported by a pin and roller at each of the ends, and only two symmetric point loads were applied to generate a bending moment to induce a bending of a curved shape. It was found that, for a given load configuration, a parabolic geometry was generated along a partial center section of the beam. The analysis carried out showed that under the load configuration analyzed, up to 66% of the beam length adopted a fully parabolic geometry. The technique proposed in this work allows for the creation of parabolas with variable focal distances, offering versatility in the design of solar concentrating systems. It also allows corrective adjustments to be made during the assembly of the complete solar concentrator system. Full article

In regions with abundant solar energy, solar water disinfection (SODIS) offers a sustainable strategy to improve drinking water access, especially in rural, off-grid communities. This study presents a numerical modeling approach to assess the thermal and microbial disinfection performance of glass-free parabolic trough collectors (PTCs). The model integrates geometric sizing, one-dimensional thermal energy balance, and first-order microbial inactivation kinetics, supported by optical simulations in SolTRACE 3.0. Simulations applied to a representative case in the Colombian Caribbean (Gambote, Bolívar) highlight the influence of rim angle, focal length, and optical properties on system efficiency. Results show that compact PTCs can achieve fluid temperatures above 70 °C and effective pathogen inactivation within short exposure times. Sensitivity analysis identifies key geometric and environmental factors that optimize performance under variable conditions. The model provides a practical tool for guiding the design and local adaptation of SODIS systems, supporting decentralized, low-cost water treatment solutions aligned with sustainable development goals. Furthermore, it offers a framework for future assessments of PTC implementations in different climatic scenarios. Full article

This article presents a database focused on measuring the experimental performance of a pilot parabolic trough collector (PTC) combined with the meteorological conditions corresponding to the installation site. Water was chosen as the fluid to recirculate through the PTC circuit. The data were recorded between August and September, assuming that global radiation was adequate for use in the concentration process. The database comprises seven experimental tests, which contain variables such as time, inlet temperature, outlet temperature, ambient temperature, global radiation, diffuse radiation, wind direction, wind speed, and volumetric flow rate. Based on the data obtained from this pilot PTC system, it is possible to provide relevant information for the installation and construction of large-scale solar collectors. Furthermore, the climatic conditions considered allow key factors in the design of multiple collectors to be determined, such as the type of arrangement (series or parallel) and manufacturing materials. In addition, the data collected in this study are key to validating future theoretical models of the PTC. Finally, considering the real operating conditions of a PTC in conjunction with meteorological variables could also be useful for predicting the system’s thermal performance using artificial intelligence-based models. Full article

The accelerating deterioration of the global environment underscores the urgent need to transition from the conventional fossil fuels to renewable energy, particularly the abundant solar energy. However, large-scale solar power integration could cause the severe grid fluctuations and compromise the operational stability. Existing studies have attempted to address this issue using hydrogen-based energy storage for peak shaving, but most suffer from low system efficiency. To overcome these limitations, this study proposes a novel solar-driven integrated energy system (IES) for hydrogen production and combined heat and power (CHP) generation, in which advanced hydrogen storage technologies are employed to achieve the efficient system operation. The system couples four subsystems: parabolic trough solar collector (PTSC), transcritical CO₂ power cycle (TCPC), Kalina cycle (KC) and proton exchange membrane electrolytic cell (PEMEC). Thermodynamic analysis of the proposed IES was conducted, and the effects of key parameters on system performance were investigated in depth. Simulation results show that under design conditions, the PEMEC produces 0.514 kg/h of hydrogen with an energy efficiency of 54.09% and an exergy efficiency of 51.59%, respectively. When the TCPC evaporator outlet temperature is 430.35 K, the IES achieves maximum energy and exergy efficiencies of 46.52% and 18.62%, respectively, with a hydrogen production rate of 0.51 kg/h. The findings highlight the importance of coordinated parameter optimization to maximize system efficiency and hydrogen productivity, providing theoretical guidance for practical design and operation of solar-based hydrogen integrated energy system. Full article

There is an urgent need to reduce greenhouse gas emissions, particularly carbon dioxide (CO₂). Currently, numerous research initiatives are underway to develop CO₂ Capture and Storage (CCS) technologies aiming for net-zero emissions, especially in sectors that are difficult to decarbonize, such as fossil fuel power generation. Integrating solar thermal energy into CO₂ capture facilities (CCFs) for fossil fuel-based power plants offers a promising approach to reduce the high operational costs associated with CO₂ capture processes. However, a comprehensive systematic review focusing on the integration of solar thermal energy with CCFs in fossil fuel power generation is currently lacking. To address this gap, this study systematically evaluates the technological frameworks involved, including (a) various generation technologies such as coal-fired Rankine cycle plants, natural gas combined cycle plants, and cogeneration units; (b) concentrated solar power (CSP) technologies, including parabolic trough collectors, linear Fresnel reflectors, solar power towers, and Stirling dish systems; and (c) post-combustion CO₂ capture systems. Additionally, this research analyzes relevant projects, patents, and scholarly publications from the past 25 years that explore the coupling of CSP technologies with fossil fuel power plants and post-combustion CO₂ capture systems. This literature review encompasses diverse methodologies, such as innovative patents, conceptual models, evaluations of solar collector performances, thermal integration optimization, and various system configurations. It also investigates technical advancements aimed at improving efficiency, reliability, and flexibility of fossil fuel power plants while mitigating the inherent challenges of CO₂ capture. Beyond the energy-focused aspects, we explore complementary circular economy strategies—such as by-product valorization and material substitution in sectors like mining, cement, and steel manufacturing—that can reduce embodied emissions and enhance the overall system benefits of solar-assisted CO₂ capture. The review employs a bibliometric approach using digital tools including Publish or Perish, Mendeley, and VOSviewer to systematically analyze the scholarly landscape. Full article

This study presents a numerical investigation of a parabolic trough absorber tube equipped with a novel Angularly Segmented Ring Turbulator (ASRT), designed to enhance heat transfer through periodic flow disturbance and improved wall–fluid interaction. The proposed ASRT geometry consists of segmented annular rings arranged along the tube length, characterized by two key parameters: the number of angular segments per ring (Nr = 4, 6, 8) and the angular spacing of each segment (α = 20° and 40°). Three dimensional simulations were performed using the finite volume method under turbulent flow conditions, with Reynolds numbers ranging from 3300 to 11,000. A non-uniform solar heat flux, obtained via Monte Carlo Ray Tracing (MCRT), was applied as a boundary condition at the outer wall to replicate realistic solar concentration. The results reveal that the ASRT significantly improves convective heat transfer, with the Nusselt number ratio $\left(Nu/{Nu}_s\right)$ reaching up to 3.7 for α = 20° and Nr = 8. This enhancement is accompanied by a moderate rise in the friction factor ratio $\left(f/f_s\right)$, reaching approximately 7.5 at Re = 3300, indicating efficient turbulence promotion with acceptable hydraulic penalties. The Performance Evaluation Criterion (PEC) ranges from 1.7 to 1.9, confirming the superiority of ASRT over the smooth tube. Full article

Parabolic trough collectors (PTCs) are effective solar thermal systems, but their performance can be significantly enhanced through surface treatments. This research investigates the enhancement of thermal performance in parabolic trough collectors (PTCs) by experimentally evaluating the results of surface coating on the absorber tube surface. To achieve this objective, a closed-loop PTC system was fabricated to conduct an experimental comparison between a conventional simple copper tube and a black-painted copper tube. The experimental setup was placed in Islamabad, Pakistan, operated under both laminar and turbulent flow conditions to measure key performance metrics, of temperature difference (ΔT) between the inlet and outlet. The results demonstrate a significant performance advantage for the black-painted tube. In laminar flow, the black-painted tube achieved an average ΔT of 3.54 °C, compared to 2.11 °C for the simple copper tube. Similarly, in turbulent flow, the black-painted tube’s ΔT was 2.1 °C, surpassing the simple copper tube’s 1.57 °C. This superior performance is primarily attributed to the black surface’s high solar absorptivity, which more effectively captures and converts solar radiation into thermal energy. The findings highlight the critical role of surface treatment in optimizing PTC efficiency and provide a practical method for improving solar thermal energy systems. Full article