Concentrated Solar Power Systems Research Articles

Land-Use competitiveness of photovoltaic and concentrated solar power technologies near the Tropic of Cancer

Solar radiation can be utilized for electricity generation through two main categories of solar power technologies: (1) photovoltaic (PV), and (2) concentrated solar power (CSP). In this study, three-dimensional computer models of electricity generation from 9 different solar power systems (4PV and 5CSP) using the simulation program Energy3D were used to establish a generic ranking of these systems in terms of the expected electric energy output during one year per unit land area. This performance metric is referred to as energy generation intensity (EGI), with ‘energy’ here referring to electric energy in particular. The analysis is aimed for low-latitude zones near the Tropic of Cancer. Solar power systems composed of long rows of connected PV modules, with single-horizontal-axis solar tracking (variable tilt), or with fixed optimized orientation were found to have the best EGI. On the other hand; heliostats with solar towers, PV units with single-vertical-axis solar tracking, and PV units with two-axis solar tracking were found to have the lowest EGI. Other four CSP systems: parabolic dishes, parabolic troughs, linear Fresnel reflectors (LFR), and compact linear Fresnel reflectors with two absorbers formed an intermediate group. Considering all of the 9 solar systems, the estimated EGI ranged from 113.1kWh/year.m2 to 227.2kWh/year.m2. The monthly contributions to EGI were contrasted; and daily and hourly energy generation intensities were examined on December21 and June21. Minor validation was performed using the simulation tool PVWatts Calculator for benchmarking, and using the web application PVGIS for PV systems calculation.

Binder jet additive manufacturing of ceramic heat exchangers for concentrating solar power applications with thermal energy storage in molten chlorides

Triply periodic minimal surface (TPMS) geometries can only be fabricated by additive manufacturing methods and are of interest for heat exchangers. Ceramic TPMS heat exchangers can operate at higher temperatures and pressures with superior performance and increased operating efficiencies compared to metal heat exchangers. The properties of ultra-high temperature ceramic (UHTC) materials are also favorable for heat exchangers and potentially suited to concentrated solar power (CSP) systems, such as those based on a molten chloride salt thermal energy storage (TES) medium used to heat CO 2 in a closed-loop Brayton power cycle. We intended to demonstrate binder jet additive manufacturing feasibility of a UHTC-TPMS structure by printing and sintering a null candidate. We aimed to achieve parts with a relative density ≥ 92 % of theoretical and to provide a TPMS part demonstration. The target density indicates the transition from intermediate to final stage sintering, a requirement to inhibit gas permeability and for sintering complex near net shapes to full density with sinter-HIP technology. The goal of the TPMS part demonstration was to determine if printing and sintering parameters developed from test coupons apply to the complex geometries that will eventually be used in a heat exchanger design. Our objective was to print cubic TPMS parts with a 9 cm 3 volume and sinter it without distorting and cracking. We were able to sinter ZrB 2 -MoSi 2 composite parts based on the Schwarz-D TPMS and achieve isotropic shrinkage up to 60 % by volume, resulting in densities ranging from 92 % to 96 % of theoretical. • Advanced heat exchanger design based on a triply periodic minimal surface (TPMS). • Ultra-high temperature ceramic (UHTC) materials of construction. • Binder jet additive manufacturing and sintering of ZrB2-MoSi2 Schwarz-D cells. • Utilization of conventional powder feedstocks. • Achieving isotropic shrinkage and densities of 92–98 % of theoretical.

Microstructure and optical properties of W/W‐WxN/WOx multilayer metal‐dielectric solar selective absorbing coating

The solar spectrum selective absorption coating (SSAC), as a core component of the concentrated solar power (CSP) system, faces increasingly stringent performance criteria as concentrated solar thermal power production technology advances and becomes more industrialized. Due to atom interdiffusion at the layer border, the current traditional composition and structure of progressive absorption coatings suffer from coating property loss at high temperatures. In this work, W/W‐WxN/WOx SSACs were prepared utilizing a medium frequency reactive magnetron sputtering approach with transition metal nitride as the absorption layer and WOx film with superior intrinsic absorption as the antireflection layer. The optical properties, structural composition, and thermal stability of the coatings were evaluated and characterized using field emission scanning electron microscopy (FE‐SEM), X‐ray diffractometer (XRD), ultraviolet–visible spectrophotometer (UV‐vis), X‐ray photoelectron spectrometer (XPS), and thermal emission meter, and the coatings' failure model and failure mechanism were established and explained. The experimental results demonstrated that the coating had outstanding spectrally selective absorption performance with an absorbance of 0.90 and thermal emissivity of 0.08 under air circumstances, as well as high thermal stability at 250°C and 20 h.

Evaluating the Corrosion Resistance of Inconel 625 Coatings, Processed by Compact Plasma Spray, for Applications in Concentrating Solar Power Plants

Thermal energy storage (TES) systems have paramount importance in the design of Concentrating Solar Power (CSP) plants. TES systems allow storing the energy collected from solar radiation as heat energy in a thermal fluid and, in that way, extending the energy duration period of the plant and making the produced electricity dispatchable, depending on the actual demand and not only on the availability of the sun. The thermal fluids, synthetic oils, or molten salts, usually operate at temperatures from 500°C up to 800°C. The harsh operative conditions bring out issues related to the compatibility with the construction materials of CSP components, i.e., carbon and stainless steel. Coating of low-alloy structural steel with high-resistant materials has been addressed as a promising solution for mitigating the corrosion in TES system components. Compact plasma spray process was used to deposit Inconel 625 alloy onto T22 carbon steel coupons. Nitrate salts mixture, 60%NaNO3-40KNO3, commonly employed in CSP systems as operative and thermal storage fluid was used as corrosion medium. The tests were conducted by immersing coated and uncoated samples in molten salts at 500°C for 1, 3 7, and 14 days to assess the corrosion behavior of the In625 coatings. After 24 hours of exposition to molten nitrate salts, the T22 surface showed a pronounced oxidized layer having a thickness of approximately 20 µm. This layer is mainly composed of oxygen, iron, and chromium, which are the main constituents of carbon steel, with a few traces of sodium and potassium derived from the reaction of salts with the steel. Inconel 625, on the other hand, showed the formation of very thin scales of corrosion products localized only on the surface of the sample. Longer exposition is expected to produce a more pronounced degradation of uncoated steel, but barely affect the Inconel 625 coating

Spinel Cu-Mn-Cr Oxide Nanoparticle-Pigmented Solar Selective Coatings Maintaining >94% Efficiency at 750 °C.

High-temperature concentrating solar power (CSP) system is capable of harvesting and storing solar energy as heat toward cost-effective dispatchable solar electricity. Solar selective coating is a critical component to boost its efficiency by maximizing solar absorptance and minimizing thermal emittance losses. However, maintaining a high solar-thermal conversion efficiency >90% for long-term operation at ≥750 °C remains a significant challenge. Herein, we report spray-coated spinel Cu-Mn-Cr oxide nanoparticle-pigmented solar selective coatings on Inconel tube sections maintaining ≥94% efficiency at 750 °C and ≥92.5% at 800 °C under 1000× solar concentration after 60 simulated day-night thermal cycles in air, each cycle comprising 12 h at 750 °C/800 °C and 12 h cooling to 25 °C. The solar spectral selectivity is intrinsic to the band-to-band and d-d transitions of nonstoichiometric spinel Cu-Mn-Cr oxide nanoparticles. This feature offers a large fabrication tolerance in nanoparticle volume fraction and coating thickness, facilitating low-cost and scalable spray-coated high-efficiency solar selective absorbers for high-temperature CSP systems.

Experimental investigation of low velocity and high temperature solid particle impact erosion wear

Next generation Concentrating Solar Power (CSP) plants utilizing solid particles as the heat transfer medium (HTM) are expected to achieve greater operational efficiencies. However, the erosion from the solid particles can cause significant damage to component materials. Low particle speeds (1–2 m/s) are proposed as a means of preventing excessive damage to containment materials. Within the current investigation, solid particle erosion of three potential containment materials, stainless-steel grade 316L, a nickel alloy (Inconel 740H), and a refractory material (Tufcrete 60 M), are examined at a particle impact speed of 1.6 m/s. CarboBead-HSP 40/70 particles, a candidate HTM for CSP systems, impact the specimens at a relatively high impact angle of 60° based on containment design criteria. Experiments were conducted at ambient temperature and 800 °C to examine erosion of the materials at very low impact speeds and determine how temperature effects erosion. Initial results revealed surprising outcomes inconsistent with available literature: ambient temperature erosion of SS316L is an order of magnitude lower than IN740H, but erosion (erosion-corrosion) of SS316L at 800 °C surpasses IN740H by two orders of magnitude. Results suggest removal of oxide layers (erosion-corrosion) is responsible for the significant erosion that was observed even at these low particle speeds.

Numerical analysis using SolTrace software to determine the size and position of a central receiver for ganged heliostat system

Concentrated solar power (CSP) technology has become a promising technique for harnessing the sun’s energy. Ganged heliostat system, also called as central receiver system (CRS), a type of CSP system that uses a field of radially distributed heliostats (mirrors), which track the position of the sun in two axes and focus the sunlight on the centrally placed receiver. Heliostats are used to concentrate solar rays on the receiver, producing a huge amount of energy which can later get converted into electricity or heat. The receiver is kept at a sufficient height to absorb maximum reflected rays. In the present work, a numerical analysis method is used to optimize receiver design parameters such as receiver size, its position in horizontal and vertical planes, and to predict the heat flux intensity at the receiver surface. However, there is no direct method to decide these parameters and often results in a loss of time while optimizing them. In this research paper, a simple methodology has been proposed to design a central receiver for CRS consisting of ganged heliostat system using SolTrace 3.1.0 software. This method is effective in determining the size, the position of the receiver and heat flux distribution at the receiver surface in the initial phase of receiver system design.

Exploring the techno-economic feasibility of new bioeconomy concepts: Solar-assisted thermochemical biorefineries

Integrating thermochemical biomass conversion and solar thermal energy is an emerging concept for the sustainable production of electricity, biofuels, and other renewable products. This study uses a utility supply approach to assess the techno-economic feasibility of thermochemical biorefineries (TBRF) assisted by concentrated solar power (CSP) systems. Three TBRF scenarios were modelled to produce dimethyl ether (DME) from gasified biomass (500 MWth), considering different alternatives for syngas upgrading. A CSP plant of 50 MWe and 15 h of thermal energy storage (TES) was incorporated to increase the system power generation. The assessment of the six scenarios (3 stand-alone and 3 CSP-assisted) was based on a specific location to show its potential: the solar resource of Seville (Spain) and the electricity prices in the Iberian market, both at hourly resolution. The CSP-assisted scenarios show fuel upgrading in the range of 2–4%, up to 85% of electricity demand coverage and power surpluses of up to 52% of its annual demand. However, the inclusion of a CSP block leads to an increase in investment costs of up to 74% and a decrease in the internal rate of return (IRR) of 9.2 points compared to a stand-alone TRBF. The DME minimum selling price ranged from 14 to 18.1 USD/GJ for the stand-alone scenarios and between 18.3 and 21.2 USD/GJ for the CSP-assisted scenarios. Furthermore, these results suggest that modular integration based on commercially available technologies may constitute a first step towards the feasibility of future biorefineries.

Angular absorptance and thermal degradation analysis of TiB2/Ti(B,N)/SiON/SiO2 multilayer solar absorber coating

AbstractMultilayer solar selective absorber coatings have been developed in the last few decades. The thermal stability in terms of microstructure gives an insightful understanding of the optical properties of such coatings. In this context, we extensively utilized transmission electron microscopy (TEM) analysis to establish the thermal stability of TiB2/Ti(B,N)/SiON/SiO2 coating, under thermal cycling/continuous heating to 500°C in vacuum for 250 h. In particular, this work reports the variation in the solar absorptance of TiB2/Ti(B,N)/SiON/SiO2 coating with different angles of incidence of the solar radiation. Extensive analysis using the TEM technique reveals the presence of oxide interlayers that act as diffusion barrier layers to enhance the thermal stability of the coating. Computational simulation using SCOUT software validates the measured reflectance spectrum of the developed multilayer coating. The minor changes in absorptance and emissivity after heat treatment in vacuum at 500°C, together with high solar absorptance over a broad angular variation, establish the potential application of TiB2/Ti(B,N)/SiON/SiO2 as a selective coating in concentrated solar power systems.

Performance Investigation of Supercritical CO2 Brayton Cycles in Combination With Solar Power and Waste Heat Recovery Systems

Abstract A performance assessment of advanced sCO2 Brayton cycles integrated with a concentrated solar power and waste heat recovery systems was conducted. Five advanced sCO2 Brayton cycles are examined for the bottoming cycle: dual heater, dual expansion, cascade, partial recuperation, and Kimzey cycles. This study reveals that the dual heater and dual expansion cycles have the best performance among the advanced sCO2 Brayton cycles considered. The findings reveal that the highest cycle efficiency is for the dual heater and dual expansion cycles (29.18%) followed by the Kimzey cycle (27.73%), then the cascade cycle (26.29%). Consequently, the least cycle efficiency is for the partial recuperation cycle (25%). Furthermore, the highest net power takes place in the dual heater and dual expansion cycles. Finally, the findings demonstrate that increasing the pressure ratio of advanced sCO2 Brayton cycles, within the range considered, results in a reduction of the cycle efficiency.

NiO nanowire-containing heat transfer nanofluids for CSP plants: Experiments and simulations to promote their application

Concentrating solar power (CSP) is considered a clean, renewable and sustainable energy with a significant potential to become an alternative to polluting fossil fuel-based technologies. Among CSP collectors, parabolic-trough collectors (PTC) are the most mature technology, representing nearly 90% of the currently installed collectors in CSP plants worldwide. In this technology, a heat transfer fluid (HTF) carries the thermal energy absorbed to a power block to produce electricity. Improving the thermal properties of the conventional HTF could lead to an improvement of the efficiency of CSP plants. In this sense, the use of nanofluids as the HTF in these plants can be a promising choice. Here, polycrystalline NiO nanowire-containing nanofluids have been prepared using the conventional HTF used in CSP plants as the base fluid; that is, the eutectic and azeotropic mixture of biphenyl (26.5%) and diphenyl oxide (73.5%). The stability, rheological and thermal properties have been characterized, and an analysis of the performance of the nanofluids prepared in standard and volumetric absorbers have been carried out. The overall CSP system performance can be increased up to 34.8% using the nanofluid in a surface collector or up to 34.3% using the nanofluid in a volumetric collector, which are better than the predicted 28.5% using the conventional HTF in a standard surface collector, thanks to the improvements in thermal properties, both specific heat and thermal conductivity. Finally, from molecular dynamics simulations we determined that the mean free path of thermal vibrations is longer for monocrystalline NiO nanowires. Thus, the development of strategies for obtaining this kind of nanostructures is of great interest because they can further improve the efficiency of these nanofluids.

An innovative concentrated solar power system driven by high-temperature cascade organic Rankine cycle

Direct steam generation (DSG) solar power systems eliminate synthetic oils and molten salts in the solar field and enable efficient heat collection. Commercial DSG solar plants usually have a steam generation temperature of 250–285 °C to reduce the technical challenges of wet steam turbines and the costs of high-pressure water storage tanks. The power conversion efficiency is relatively low due to the limited steam generation temperature. This paper proposes a high-temperature solar power system driven by the cascade organic Rankine cycle (CORC). It has three features: water/steam for solar heat transfer, water and phase change material (PCM) for heat storage, and CORC for power conversion. It is the first time that the storage tank temperature is independent of the steam generation temperature in a DSG. Steam can be generated in the solar field at a temperature of 310 °C or even 370 °C. The fundamental of the innovative system is illustrated. The thermodynamic performances during the normal operation and discharge processes are investigated. The results show the maximum thermal efficiency of the CORC system in the normal operation mode is 32.85% at a steam temperature of 311 °C, while the top and bottom cycle efficiencies are 15.38% and 20.86%, respectively. The efficiency increases to more than 37% at 370 °C. Combining the two-tank storage and the PCM unit can overcome the problems of decreasing the heat release rate from PCM during heat discharge while maintaining the CORC system's power output and prolonging the heat storage time. The proposed system is potentially more cost-effective than the existing DSG solar plants.

Effects of Volumetric Property Models on the Efficiency of a Porous Volumetric Solar Receiver

A porous volumetric receiver is the key component in concentrated solar power systems. In this paper, we investigate the effects of volumetric parameter models on the heat collection efficiency of the volumetric receiver by numerical simulations with the combination of local thermal non-equilibrium and discrete ordinate methods. Seven volumetric convective heat transfer coefficient models and three extinction coefficient models were investigated. The efficiencies calculated using these models were compared among each other. The results show that volumetric convective heat transfer coefficient models have significant effects with a maximum difference of 27.7% in receiver efficiency for these models. Extinction coefficient models have less effects on receiver efficiency with a maximum difference of 7.3%.

Techno-economic optimisation of a sodium–chloride salt heat exchanger for concentrating solar power applications

To enhance the economic viability of Concentrating solar power (CSP) plant, recent efforts have been directed towards employing high-temperature working fluid in the receiver and incorporating higher-efficiency power cycles. This work presents a techno-economic analysis of a sodium–chloride salt heat exchanger included in a sodium-driven CSP system with a supercritical CO2 power block. A quasi-steady state heat exchanger model was developed based on the TEMA guidelines, with the possibility of being customised in terms of media adopted, constraints, boundary conditions, and heat transfer correlations. The sodium–salt heat exchanger has been designed aiming at minimising the Levelized Cost of Electricity (LCOE) of the plant. The performance and the design of the proposed heat exchanger have been evaluated via multi-objective optimisation and sensitivity analyses. Results show that advanced CSP systems employing sodium and an indirect chloride salt storage can represent an economically viable solution and can drive towards the future goal of 5 USD/MWh. For a base-case 100 MWe plant with 12 h of storage, a LCOE of 72.7 USD/MWh and a capacity factor (CF) higher than 60% were reached. The techno-economic investigations showed the potential LCOE reduction of 6% as well as the flexibility and robustness of the heat exchanger model. The developed tool lays the groundwork to explore potential improvements of this new generation of CSP systems.

Robust corrosion performance of cold sprayed aluminide coating in ternary molten carbonate salt for concentrated solar power plants

In concentrated solar power (CSP) technology, high temperature corrosion is a key issue for material selection. In this context, a homogeneous and crack-free FeAl coating with high Al content was prepared by using cold spray (combined with a post heat treatment) to improve the corrosion resistance of stainless steel 316 L (SS316L) in molten carbonate salt for CSP applications. A series of immersion corrosion tests were performed to explore the corrosion behavior of the prepared aluminide coating in the LiNaK molten carbonate salt at 700 °C. The results demonstrated that the corrosion resistance of SS316L in the molten carbonate salt can be greatly improved by the prepared aluminide coating. This is attributed to the formation of a continuous dense LiAlO2 layer on the surface of the coating during corrosion. Although an α-LiAlO2 → γ-LiAlO2 phase transformation occurred during corrosion, it showed little influence on the corrosion performance of the prepared coating under the present experimental conditions. Furthermore, the coating remained intact even after 1000 h of corrosion. It is envisaged that the prepared coating has broad application prospects for CSP system with molten carbonate salt medium.

집광형 태양열 발전 시스템에서의 태양열유속 분포의 변화에 따른 열전달 수치해석 연구

Concentrating solar power system (CSP) is one of the renewable energies which accumulates solar energy concentrated by condensing mirrors and reflectors in solar absorbers. Boiled water then operates steam turbines to generate electricity. So far, many studies have been conducted for optimization design of CSP which are mostly focused on comparing the materials and dimensions of the absorber to increase thermal efficiency. In this study, we tried to compare heat transfer in solar receiver from different heat flux distributions considering daily change of the azimuthal angle of the solar radiation. A Numerical study was performed using ANSYS FLUENT and appropriate temperature boundary condition was enforced at the receiver inlet using User-Defined-Function. Energy balance was modeled at the receiver inlet considering convectional and radiational loss to the surrounding. The amount of heat transfer to the receiver and heat loss to the surrounding from several characteristic heat flux distributions are compared. In addition, effects from the convective heat transfer coefficient, thermal conductivity, and porosity of the solar absorber are investigated. It has been found that eccentric distribution of the solar heat flux deteriorates thermal efficiency considerably. It is also found that heat transfer becomes larger with small convective heat transfer coefficient and large thermal conductivity. With lowering the porosity, the amount of heat transfer generally increases. But the gain is rather small at very low value with significantly high pressure drop.

Experimental Study of Eutectic Molten Salts NaCl/KCl/ZnCl2 Heat Transfer Inside a Smooth Tube for High-Temperature Application

AbstractEutectic salts NaCl-KCl-ZnCl2 and NaCl-KCl-MgCl2 are two of the chloride salt systems that are promising for being used as high-temperature heat transfer fluid (HTF) and thermal energy storage (TES) materials in a wide range of temperatures from 230 °C to 750 °C in concentrated solar thermal power systems. To conduct measurement of the heat transfer coefficient of the molten salt at high temperatures, a circulation system and instrumentation of flow and heat transfer was constructed. Experimental measurement of the convective heat transfer coefficients of NaCl-KCl-ZnCl2 (molar fraction: 13.8–41.9–44.3%) inside tubes has been accomplished to find the most suitable heat transfer correlations. Experience of salt processing and operation of the high-temperature heat transfer test system was obtained. Two correlations, Dittus-Boelter equation and Gnielinski’s correlation for Nusselt number against Reynolds number and Prandtl number, are evaluated using the test results, and the latter correlation is recommended due to its better agreement of prediction against tested data.

Combined direct oxy‐combustion and concentrated solar supercritical carbon dioxide power system—Thermo, exergoeconomic, and quadruple optimization analyses

For the global future energy systems, concentrated solar power (CSP) and direct CO2 capture systems are of the most important key technologies, however, each of these systems has shortcomings. This study addresses the solar intermittency and power control complexity of the CSP systems and the substantial energy penalty of the direct oxy-combustion (DOC) supercritical carbon dioxide (sCO2) power systems by integrating both systems. Herein, innovative power cycle configurations that integrate the CSP tower system with DOC sCO2 power cycle are introduced. The configurations include two basic cycles for comparison and validation purposes and three integrated cycles. The basic configurations are: an intercooled sCO2 power cycle driven by DOC system (S1), and a stand-alone basic CSP tower system (S2). The integrated configurations are: CSP/DOC system where the CSP works as a preheater (S3); CSP/DOC system where the CSP works as a reheater (S4); and CSP/DOC system where each system heats part of the working fluid to drive its high-pressure turbine (S5). The hybrid configurations reduce the fuel and the parasitic power consumptions of the basic DOC systems (S1) and reduce the capital cost associated with the conventional CSP systems (S2) by eliminating the need for thermal storage. Over practical ranges of operational parameters, comprehensive thermoeconomic, exergoeconomic, and optimization analyses for the proposed configurations are performed. Compared to the conventional CSP system, the LCOE of the hybrid system is lower by 50%. Among the hybrid configurations, the energetic and exergetic performances of S4 are the best with the lowest LCOE. According to the optimization analysis, S4 has a thermal efficiency of 55.29% at LCOEs of 7.705¢/kWh. S3, S5, S2, and S1 have thermal efficiencies of 52.90%, 48.72%, 45.56%, and 40.54% at LCOE of 7.970, 8.138, 7.864, and 6.351¢/kWh, respectively.

Assessing the Hybridization of an Existing Geothermal Plant by Coupling a CSP System for Increasing Power Generation

Concentrated Solar Power (CSP) and geothermal energy systems are outlined as two of the most promising technologies for sustainable and reliable electricity generation. Several studies in the technical literature have pointed out that the hybridization of solar and geothermal energy sources could lead to a reduction of the levelized cost of energy (LCOE) of geothermal systems, as well as improving the capacity factor of CSP systems. However, the technical literature shows that the integration of solar thermal collectors does not present a positive impact in all scenarios analyzed. The present study aims to further analyze the competitiveness of the hybridization of solar and geothermal systems under high irradiation conditions such as those observed in the Andean region in northern Chile. The evaluation was carried out by coupling a thermodynamic model in Engineering Equation Solver (EES) with a solar thermal model in the System Advisor Model (SAM). The assessment considers the configuration of an existing geothermal plant, considering the design constraints associated with the actual operating conditions of the plant. The analysis is based on an energy and exergy assessment, allowing us to identify the efficiency of the subsystems introduced for the hybridization and assess the competitiveness of the hybrid schemes by an economic assessment in terms of the LCOE. The results show that the hybrid schemes allow a reduction of the LCOE of a geothermal stand-alone plant by about 10 USD/MWh, increasing the competitiveness of the geothermal system. However, a large variation on such a reduction is observed depending on the size of the solar field and the storage tank of the solar system.

Air curtains for reduction of natural convection heat loss from a heated plate: A numerical investigation

Concentrating solar power (CSP) plants encounter inefficiencies at all stages of electricity generation. Convection from the solar-thermal receiver is a significant mode of heat loss in CSP systems, and is challenging to mitigate. This study investigates the reduction of convection losses by using a planar jet that disrupts the buoyant flow arising from the heated surface of an external CSP receiver. An isothermal flat plate with a height of 1.8 m was used to model the receiver, and a planar jet air curtain with a nozzle thickness of 3 mm was introduced near the upper edge of the wall. A computational fluid dynamics model was first validated and subsequently implemented to conduct a parametric study on the heat transfer from the isothermal plate with an air curtain varying four parameters: jet speed, jet angle, plate temperature and plate inclination. The results showed that the air curtain generates a stagnation zone adjacent to the wall which successfully reduces local convective heat losses. The effectiveness of an air curtain is defined here as the relative reduction in the local heat loss due to the air curtain, compared to the case of natural convection alone. A local maximum of 31.2% effectiveness is achieved in the stagnation zone below the jet outlet for a vertical wall with a jet speed of 2.5 ms−1 and jet angle of 45∘. The air curtain effectiveness at the stagnation region was found to decrease with increasing jet speeds, whereas the effectiveness increased near the laminar-to-turbulent transition region with increasing jet speed. Smaller air curtain angles relative to the wall resulted in lower effectiveness. A 45∘ air curtain on a vertical wall can offer performance benefits that are similar in magnitude to inclining a wall from the vertical. A higher wall temperature was accompanied by better effectiveness near the jet outlet, particularly in the stagnation region, while lower wall temperatures produced higher effectiveness further from the jet. Therefore, an air curtain can be used to reduce convective heat losses locally from a heated flat surface, including potentially when applied to CSP receivers.