Concentrated Solar Power Research Articles

Tuning optical properties of sustainable inorganic bismuth-based perovskite materials with organic ligands

We report a facile and environmentally friendly ball milling method for synthesizing Cs3Bi2Cl9 nanocrystals at different ball milling times: 30 min (BM1), 120 min (BM2), and 240 min (BM3). Structural analysis confirmed the formation of crystalline nanostructures. Optical studies revealed a tunable bandgap influenced by particle size, with a blue shift observed for smaller nanocrystals. Importantly, Cs3Bi2Cl9 demonstrated potential for optoelectronic applications as indicated by its interaction with 2,3-diaminonaphthalene and reduced charge carrier lifetime. These findings contribute to the growing interest in lead-free perovskites as sustainable alternatives for light-harvesting and conversion technologies. Increasing ball milling time from 120 to 240 minutes improved thermal stability between 200 °C and 610 °C. BM1 perovskite crystals showed significantly lower thermal stability, suggesting that the synthesis process influences crystal structure and thermal properties. However, thermogravimetric analysis (TGA) showed that BM2 and BM3 perovskite crystals exhibited exceptional thermal stability, withstanding temperatures up to 438.6 °C and 439 °C, respectively, without significant weight loss. This superior stability expands potential applications to high-temperature environments like concentrated solar power systems.

The potential role of concentrated solar power for off-grid green hydrogen and ammonia production

This paper investigates the potential role of concentrated solar power (CSP) in off-grid green electrolytic hydrogen and ammonia production using an open-source techno-economic assessment optimisation model. The green ammonia plant comprises a flexible Haber-Bosch loop, an electrolyser park, a desalination plant, storage systems (thermal, electrical, and hydrogen), and a power supply optionally including wind power, solar photovoltaic (PV), and CSP (solar tower or parabolic trough collectors). Various system configurations and cost assumptions are tested to evaluate when CSP technologies are economically viable for green fuel production. Results demonstrate that CSP and thermal energy storage (TES) technologies can play a minor but useful role in providing nighttime power supply to the ammonia plant, in combination with onshore wind power and electrical storage. Solar PV with 1-axis tracking remains the primary power provider, and the optimal system always includes large-scale hydrogen storage. In the cheapest configuration, the LCOA reaches 646 €/tNH3. With an 80% reduction in CSP and TES costs, CSP technology becomes a major player in power production. In scenarios where hydrogen storage is not feasible and the ammonia plant lacks full flexibility, a 20% cost reduction (to 2750 €/kW) is enough for them to become major power providers.

Comprehensive assessment and energetic-exergetic performance optimization of a new solar thermal electricity system based on Scheffler-type receivers combined with screw-type volumetric machines

This study explores the potential of a novel solar-powered cascade Rankine cycle system based on Scheffler-type receivers combined with screw expanders. Specifically, in this solar power system, steam is generated in the Scheffler-type receiver, which proves to be well performing compared with other technological solutions to exploit solar energy, due to satisfactory efficiency of the focal receiver that is able to curtail heat losses, even at high evaporation temperatures. Subsequently, steam expands in the screw machines which, unlike conventional steam turbines, are specially fitting in energy conversion with vapor-liquid mixes in the field from tens to hundreds of kW. In the present study, comprehensive assessment of this renewable energy power system is thoroughly conducted in a large range of operating states. For this purpose, specific numerical models and basic criteria fixed for the screw expanders and Scheffler receivers part-load behavior are combined with thermodynamic formulations established for energetic-exergetic performance optimization of the entire solar thermal electricity plant. Hence, parametric optimization of the major thermodynamic factors involved at part-load operating situations is conducted to enhance the energetic and exergetic efficiencies of the designed solar thermal power system.

Investigation of the high temperature molten salt corrosion properties of Inconel625 alloy with Al

The Inconel625 (In625) alloy is one of the main materials in heat receivers of concentrated solar power (CSP). To further improve the corrosion resistance of heat receivers in molten salt, Al element that can form an oxide film was added into In625 alloy. In this study, In625 alloy with 3 wt% Al was prepared, and its corrosion resistance in carbonate (Li2CO3-Na2CO3-K2CO3) at 650 °C was studied. Results showed that a continuous dense oxide protective film (Al2O3 + LiAlO2) in surface of sample was formed by adding Al element during high temperature molten salt corrosion, which reduced the corrosion rate of In625 alloy. The corrosion rate of In625 alloy with 3 wt% Al corroded for 48 h and 120 h were 44 μm/year and 89 μm/year, respectively.

Electrochemistry of Phase-Change Materials in Thermal Energy Storage Systems: A Critical Review of Green Transitions in Built Environments

This article reviews recent research on phase-change materials (PCMs) used in thermal energy storage systems with the aim of enhancing their performance. The study explores various methods to improve heat transfer in PCMs, such as microencapsulation, infill materials, fins and nanofluids. Additionally, it evaluates techniques to boost heat transfer in latent heat thermal energy storage (LHTES) systems and investigates ways to increase thermal conductivity using porous and low-density materials. PCMs store thermal energy, making them suitable for use in solar energy systems when solar energy is not available. The need for eco-friendly alternatives to conventional heating and cooling in global construction and the significant energy consumption of buildings has driven research on this topic. As such, this study additionally examines current advancements in free cooling systems with latent heat storage to identify the key factors affecting their effectiveness. The findings show that using PCMs for overnight cooling maintains the room temperature within the comfort zone and reduces the cooling loads in various climates. Using machine learning methods, this study also compares recent advancements in the use of PCMs in various solar energy systems, including solar thermal power plants, solar air purifiers, solar water heaters and solar appliances. Results derived feature key factors crucial for the optimal selection of PCMs and the challenges associated with sustainable green transitions in built environments. HIGHLIGHTS This review provides an in-depth examination of PCM thermal energy storage systems. This study investigates the use of fillers, nanofluids, and nanoparticles for enhanced heat transfer. Analytical methods for boosting the PCM thermal conductivity are briefly outlined. Geometric design and thermal conductivity enhancement affect the Latent Heat Thermal Energy Storage (LHTES). The assessment also evaluates advanced free-cooling systems using the LHTES. PCMs help to store heat energy in solar systems and bridge supply gaps. GRAPHICAL ABSTRACT

Heat transfer assessment of magnetized tangent hyperbolic fluid flow through porous disk using LWCM: Application in solar thermal power plant

Heat transfer assessment of magnetized tangent hyperbolic fluid flow through porous disk using LWCM: Application in solar thermal power plant

Siting Analysis of a Solar-Nuclear-Desalination Integrated Energy System

Nuclear power is typically deployed as a baseload generator. Increased penetration of variable renewables motivates combining nuclear and renewable technologies into Integrated Energy Systems (IES) to improve dispatchability, component synergies and, through cogeneration, address multiple markets. However, combining multiple energy resources heavily depends on the proper selection of each system’s location and design limitations. In this paper, co-siting options for IES that couple nuclear and concentrating solar power (CSP) with thermal desalination are investigated. A comprehensive siting analysis is performed that utilizes global information survey data to determine possible co-siting options for nuclear and solar thermal generation in the United States. Viable co-siting options are distributed across the Southwestern U.S., with the greatest concentration of siting options in the southern Great Plains, although siting with higher solar direct normal irradiance is possible in other states such as Arizona and New Mexico. Brackish water desalination is also attractive across the southwest U.S. due to high water stress, but for brackish water desalination reverse osmosis (an electricity driven process) is most cost- and energy-efficient, which does not require co-siting with the thermal generator. The most attractive state for nuclear and thermal desalination (which is more attractive when using seawater) is Texas, although other areas may become attractive as water stress increases over the coming decades. Co-siting of all CSP and thermal desalination is challenging as attractive CSP sites are not coastal.

Axial Flow Fan Performance in a Forced Draught Air-Cooled Heat Exchanger for a Supercritical Carbon Dioxide Brayton Cycle

Abstract An axial flow cooling fan has been designed for use in a concentrated solar power plant. The plant is based on a supercritical carbon dioxide (sCO2) Brayton cycle, and uses a forced draft air-cooled heat exchanger (ACHE) for cooling. The fan performance has been investigated using both computational fluid dynamics (CFD) and scaled fan tests. This paper presents a CFD model that integrates the fan with the heat exchanger. The objective is to establish a foundation for similar models and to contribute to the development of efficient ACHE units designed for sCO2 power cycles. The finned-tube bundle is simplified, with a Porous Media Model representing the pressure drop through the bundle. Pressure inlet and -outlet boundary conditions are used, meaning the air flowrate is solved based on the fan and tube bundle interaction. The flowrate predicted by the CFD model is 0.5% higher than the analytical prediction, and 3.6% lower than the design value, demonstrating that the assumptions used in the design procedure are reasonable. The plenum height is also found to affect the flowrate, with shorter plenums resulting in higher flow rates and fan efficiencies, and longer plenums resulting in more uniform cooling air flow.

Enhancing thermal conductivity of novel ternary nitrate salt mixtures for thermal energy storage (TES) fluid

Efficient thermal energy storage (TES) is crucial for concentrated solar power (CSP) plants, necessitating the exploration of advanced heat transfer fluids with enhanced thermal conductivity. Conventional binary nitrate salt mixtures have limitations in thermal performance, prompting research into ternary mixtures and nanoparticle additives. This study investigates novel ternary nitrate salt mixtures comprising potassium nitrate (KNO₃), lithium nitrate (LiNO₃), and magnesium nitrate hexahydrate (Mg(NO₃)₂·6 H₂O) as high-performance TES fluids during the during the heat absorption phase. Seven different salt compositions were synthesized and characterized using the laser flash technique to evaluate their thermal conductivity over 100–400°C. Results revealed a significant influence of composition on thermal conductivity, with maximum values during melting ranging from 0.0777 W/m·K to 0.7373 W/m·K. Melting points varied from 335 K to 340.39 K, demonstrating tailorability through compositional adjustments. Furthermore, incorporation of 0.5 wt% aluminum oxide (Al₂O₃) nanoparticles resulted in substantial thermal conductivity enhancements, with the most significant increase observed in TSF10 (from 0.0777 W/m·K to 0.491 W/m·K). These improvements are attributed to enhanced phonon transport, increased surface area, and Brownian motion facilitated by Al₂O₃ nanoparticles. The study provides a comprehensive cost analysis, including raw material costs, and discusses the potential efficiency gains for CSP applications. The findings contribute to the development of high-performance and cost-effective TES fluids, advancing the efficiency and viability of sustainable energy generation.

Thermodynamic evaluation of solar energy-based methanol and hydrogen production and power generation pathways: A comparative study

This work presents a comparative evaluation of two distinct fuels, methanol and hydrogen, production and power generation routes via fuel cells. The first route includes the methanol production from direct partial oxidation of methane to methanol using solar energy, where the methanol is condensed, stored, and sent to a direct methanol fuel cell. The second route is hydrogen production from solar methane cracking (named as turquoise hydrogen), where heat is supplied from concentrated solar power, and hydrogen is stored and directed to a hydrogen fuel cell. This study aims to provide insights into these fuels' production conditions, storage methods, energy, and exergy efficiencies. The proposed system is simulated using the Engineering Equation Solver software, and a thermodynamic analysis of the entire system, including all the equipment and process streams, is performed. The methanol and hydrogen route’s overall energy and exergy efficiencies are 39.75 %, 38.35 %, 34.21 %, and 33 %, respectively. The highest exergy destruction rate of 1605 kW is observed for the partial oxidation of methane to methanol. The methanol and hydrogen routes generate 32.087 MWh and 11.582 MWh of electricity for 16-hour of fuel cell operation for the same amount of methane feedstock, respectively. Sensitivity analysis has been performed to observe the effects of different parameters, such as operating temperature and mass flow rate of fuels, on the electricity production and energy efficiencies of the systems.

ACWA Power’s CSP Performance Models

CWA Power develops, owns, and operates several CSP projects, including the largest one in the world. One of the primary objectives for companies in the Concentrated Solar Power (CSP) sector is to lower the electricity costs associated with CSP plants. This goal extends not only to existing operational plants but also to future projects. Enhancing plant performance is a key pathway to achieving this cost reduction. CSP performance models play a pivotal role in this journey by allowing us to analyse different configurations, changes, or modifications without the necessity of their physical implementation. In 2015, ACWA Power made a strategic decision to develop its own CSP performance models. This move aimed to enhance ACWA Power’s competitiveness for upcoming projects while also supporting operational plants by identifying avenues for performance improvement. The decision was made to create models for the two prevailing CSP technologies: Parabolic Trough with thermal oil as the heat transfer fluid (HTF) and molten salt storage system, as well as solar tower with molten salts.

Development of a Novel High Temperature Continuous Particle Mass Flow Measurement Device for Particle-Based CSP Applications

Particle-based concentrating solar power (CSP) technology is one of the generation three (Gen3) CSP technologies that has potential for lowering the levelized cost of electricity produced by this solar thermal power systems. Commercially available ceramic particles, which are rated for high temperature applications up to 1200 °C, were selected for this study. This medium is commonly used as an energy carrier or heat transfer medium in Gen3 CSP research and development efforts [1]. Prior studies at the National Solar Thermal Test Facility (NSTTF) have investigated and evaluated various mass flow measurement methods, and a simple gravimetric temporal load measurement method was chosen as the best candidate for the research purpose [2]. This mass flow measurement method is a batch process and is not a viable solution for commercial-scale power generation applications based on cost, space, process control, and practical system integration factors. In-line and continuous particle mass flow measurement will play an integral role in efficient and cost effective Gen3 CSP particle technologies. Process parameters, including energy absorbed by the particles, receiver efficiency, temperature dependent flow phenomena, and general high temperature measurement reliability are all rely on repeatable and accurate measurement of particle mass flow under various operating conditions. Ceramic particles, like those used in this application, are not conventionally used as an energy carrier. A novel concept for continuous particle mass flow at a wide range of operating temperatures is currently under development and planned to be tested at the NSTTF, called the Particle In-LinE (PILE) mass flow sensor.

Economic Impact of CSP Plants with Storage Addressing the Energy Transition in Locations with High Electricity Demand in Chile

This study explores the economic implications of hybrid plants combining photovoltaic (PV) and Concentrated Solar Power (CSP) technologies with energy storage in response to Chile's ongoing energy transition. Utilizing the System Advisor Model (SAM), six diverse locations were evaluated to assess energy generation profiles, calculate the Levelized Cost of Energy (LCOE), and analyze gross margins. The key finding is that higher solar multiples or storage capacities do not consistently lead to lower LCOE, primarily due to operational strategies aligning CSP generation profiles with PV. Notably, northern regions consistently yield higher gross margins despite occasional zero marginal costs, while areas near Santiago experience lower gross margins, with Salamanca presenting the lowest margin. This highlights the critical role of available solar resources in shaping economic outcomes.

GIS-Driven Method for Site Feasibility Assessment of Large-Scale Solar Thermal Seawater Desalination: An Australian Case Study

Concentrated solar power (CSP) plants can be coupled with seawater desalination via Multi-Effect Distillation (MED) by recovering the cycle’s ‘free’ waste heat. However, project viability, based on the payback period, is contingent upon systematic consideration of climate variability, topography, water resources, markets, and natural hazards. This study describes a data-driven method for screening and then selecting optimal sites in Australia by integrating a Geographic Information System (GIS), System Advisor Model (SAM), MATLAB program, and a Multi-Criteria Decision-Making (MCDM) model. Results for potential sites based on only climate, topography, water resources, markets, and infrastructure identify approximately 2.13×105 km2 of land are suitable, granularly mainly located in the north-west and the south coastal regions with high solar resources (average direct normal irradiance (DNI) > 6 ). These regions encompass 56,000 km2 and 25,100 km2 of suitable areas, respectively, with potential payback periods as low as 12.2 years and 14.0 years. Queensland's northern coastal regions also show promise with a potential payback period of 13.4 years, but the suitable area is only 2,070 km2 due to the marine protection areas in the eastern coastal zone. New South Wales faces hurdles due to topography and lower solar resources. Model results were consistent with the development of CSP installations in Australia, particularly, the Aurora facility in South Australia. This study provides a precise delineation of CSP-MED integration regions in Australia through the multi-dimensional analysis, offering insights into payback periods, and quantifying variable impacts on project geographical, technical, and economic feasibility.

Investigation of Factors Affecting Corrosion Mechanisms in Latent Heat Thermal Energy Storage Systems

Concentrated Solar Power (CSP) plants integrated with Latent Heat Thermal Energy Storage (LHTES) systems offer a promising solution for dispatchability, reliability, and economic concerns generally associated with renewable energy technologies. These systems, however, require an operational life of up to 30 years to compete with power plant systems operating on fossil fuels. This is a significant challenge due to the high temperatures and corrosive eutectic salts utilised in LHTES systems. Additionally, these systems and its subcomponents are expected to be under varying degrees of stress due to the diurnal cyclic temperature variations inherent in the plant’s operational cycle. Hence, it is crucial to understand the various factors that can affect the operational life of materials used in such applications and conduct thorough material compatibility studies to assess the combined impact of these operating conditions on corrosion mechanisms. This study presents a novel static immersion test approach using modified Compact Tension (CT) specimens manufactured from 316L to investigate the effects of Na2CO3:NaCl (59.45:40.55 wt.%) salt, elevated temperatures (700 ℃ for up to 1000 hours), and stress on corrosion induced in the alloy. The post-exposure results are characterised with Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) shows that corrosion mechanisms are significantly affected by factors such as high operating temperatures leading to changes in both corrosion morphology and rate, high stresses causing localised preferential corrosion, as well as corrosive salt and oxygen availability affecting the type of corrosion induced.

Robust Deflectometry

Concentrating Solar Power (CSP) mirrors must have high slope accuracy in order to achieve high solar concentration. Deflectometry is an established method for measuring high-resolution, high-accuracy maps of mirror slope. In this paper we describe improvements to Sandia’s deflectometry system, SOFAST, which enable it to be accurately calibrated even in difficult conditions of poor access to system components, imperfect components, and varying ambient light. These extensions improve the robustness of the system and expand the range of problems it can solve.

Thermal Properties of Cu–Al–Ge Alloy PCM for Improving Thermal Energy Storage of Current CSP

Metallic phase change material was proposed and examined at melting/eutectic temperatures less than 600 °C for latent heat storage in concentrated solar power. The PCM alloy can potentially charge/discharge thermal energy as a sensible/latent heat at the temperature range of 414-527 °C. The working temperatures of PCM alloy are in operation temperatures of current molten-salt based CSP plant. In this study, thermal response testing of PCM alloy and sensible/latent storage unit that PCM alloy was loaded in a ceramic honeycomb were prepared in a laboratory scale. The thermal charging/discharging performance of PCM alloy and sensible/latent storage unit were experimentally examined and compared. The storage unit provided thermal release/absorption behaviour at close to temperatures of the thermodynamic equilibrium state.

Methane Assisted Chemical Looping Water Splitting Performance of Sr2FeMo0.6Ni0.4O6-δ Double Perovskite for Solar Fuels Production

In this work, we performed a preliminary investigation on the redox behaviour of Sr2FeMo0.6Ni0.4O6-δ (SFMN) double perovskite in H2-H2O and CH4-H2O redox cycles in order to explore the potential use of this oxide as an Oxygen Carrier (OC) in fuel-assisted Chemical Looping Water Splitting (CLWS) processes driven by concentrated solar energy. The results were compared with our previous findings on the Reverse Water Gas Shift Chemical Looping (RWGS-CL) reaction. The improvement in performance due to the bimetallic exsolution on the OC surface is observed. This OC exhibits interesting activity and stability over CH4-assisted CLWS cycling. Future investigations are planned to examine the structural transformations that might impact the redox behaviour of this material in water splitting processes.

Solar technology for the production of Bi/Pb superconducting ceramics and its properties

Based on the experience of isostoichiometric and isostructural oxides production using solar energy, the prospects for synthesizing of Bi/Pb superconducting ceramics are shown. The principle of technology in the Large Solar Furnace (Parkent), the influence of gradient conditions on the formation of the oriented structure of crystallites-nuclei, and the connection of the innate properties of precursors with the lamellar morphology and phase composition of massive ceramics are described. The homophase composition of Bi/Pb ceramics was determined. Graphs of resistance and voltage of BSCCO in the temperature range 80-320K are presented. Anomalous of resistance and magnetic susceptibility in bismuth cuprates synthesized by solar energy were observed. Experimental graphs in resistance and magnetic susceptibility changes represent dependencies characteristic of the potential superconducting transitions. The manifestation of the Meissner effect at room temperature and normal atmospheric pressure and daylight, and under the influence of light is shown. The properties of Bi/Pb ceramics are explained by the connection with the innate properties of precursors obtained by concentrated solar energy.

Thermal-mechanical coupling characteristics of large-scale molten salt storage tanks under stable operating conditions with varying liquid levels

The large-scale molten salt storage tank is a critical component of the thermal storage system employed in concentrating solar power (CSP) plants. The storage tank is subjected to complex conditions, including high temperature, fluctuating hydrostatic pressure, and thermal stress. Therefore, it is imperative to investigate the thermal-mechanical coupling characteristics of the tank during stable operation under varying liquid levels to comprehensively understand its behavior. The study commences by establishing thermal and stress analysis models for the tank, laying the foundation for subsequent investigation. Subsequently, a comprehensive thermal-mechanical coupling model is constructed using a sequential coupling approach, enabling a more accurate representation of the system's behavior. Finally, an in-depth study is conducted to explore the thermal-mechanical coupling characteristics of storage tanks at various liquid levels. The results indicate that radiation emitted by high-temperature air, confined in the top space of the tank, induces a temperature differential of approximately 5 °C between the tank's roof and the molten salt confined within it. Furthermore, heat loss from the roof accounts for 53 % of the overall heat loss. Thermal stress analysis of each weld seam connecting the tank into an integration reveals that the inner surface experiences tensile stress, while the outer surface undergoes compressive stress, primarily influenced by radial stress. Under the influence of thermal-mechanical, the coupling effect leads to compressive stress in the form of thermal stress, resulting in a decreasing trend in stress on the inner surface of the weld seam. The radial compressive stress on the outer surface reaches approximately 140 MPa, while the tank wall is primarily subjected to circumferential forces. The temperature exerts a negligible impact on the stress of the tank wall, yet it significantly affects its deformation. The stress evaluation of hydrostatic pressure and thermodynamic coupling under different liquid levels is carried out, and the results meet the strength requirements.