Linear Fresnel Reflector Research Articles

Effects of dust and rainfall on the relative reflectivity of linear Fresnel reflectors

Dust and rainfall have been key issues affecting outdoor solar concentrating systems. This study aimed to accurately evaluate the specific effects of dust and rainfall on linear Fresnel reflectors in semi-arid regions. Targeted outdoor experiments on dust and rainwater were conducted in Hohhot, Inner Mongolia, from September to December 2023. A predictive model is developed to assess the effect of rainfall on reflectivity under conditions of dust accumulation, based on the physical properties of outdoor-exposed dust. The study reveals that after 60 days of exposure, the reflectivity decreased at a rate of 0.25 % per day due to mirror dust, particularly within the 380–780 nm wavelength range, reaching 21.62 %. The rainfall leads to four distinct conditions, namely pitting, surface corrosion, gully corrosion, and overall corrosion on the dusty mirror. During the gully corrosion and corrosion stages, the reflectivity significantly improved. Rainfall below 0.4 mm barely cleaned mirror dust, whereas rainfall exceeding 26.70 mm provided substantial cleaning but reached a saturation point with additional rainfall. These findings contribute to the development of cost-effective cleaning strategies for similar climatic conditions.

Simulation of 1 MWe hybrid solar power plant by the use of nano-fluid with eccentric backup system.

In past years, concentrated solar power (CSP) with an energy backup system has been a unique renewable energy utilization system among intermittent renewable energy systems. It could allow a CSP plant to operate as a base load system in the future. This paper simulates a solar power plant for 1 MWe. Parabolic trough collector (PTC) array and linear Fresnel reflector (LFR) field attached consecutively to produce superheated steam at 40MPa. The Rankine cycle has been used to run the steam turbine and an electricity generator is attached to a steam turbine to convert mechanical energy into electrical energy. Maximum temperature attained at the turbine inlet is 418.13 ˚C in 12:00-13:00 time slot in the month of January. Results show that solar power plant is feasible to produce 1 MWe. The minimum value of the power produced by the generator is 1.01 MWe in November in the 10:00-11:00 time slot whereas the maximum value of generated power is 1.57 MWe in December in the 11:00-12:00 time slot. The overall efficiency of power generated by the Rankine cycle is 21.25% in January in the 10:00-11:00 time slot. An energy storage system is attached to the system to work at night hours or in cloudy weather conditions.

Design and Preliminary experiment of an Off-axis aequilate-mirrors linear Fresnel concentrator with sunlight self-adaptive feature

The Off-Axis Linear Fresnel Reflector (LFR) is an innovative, compact solar concentrator designed to reduce device height and wind-load without compromising efficiency. It is crucial in applying LFR devices to applications such as building façades. To this aim, The Off-axis LFR design is introduced to addressing the inter-mirror blocking issue that diminishes the efficiency of conventional LFRs. Initially, an optimized Aequilate-mirrors design was proposed to reduce manufacturing complexity and cost. Subsequently, a crank-slider mechanism was introduced as a solution to the issue of inconsistent angle adjustment among the mirrors. Additionally, the paper details the sunlight self-adaptive feature of the Off-axis LFR concentrator, where the LFR mirrors can independently rotate to track the sun’s position, adaptively altering the mirror array’s profile and sunward aperture. This feature maximizes the device’s sunlight harvesting capacity, particularly in angled sunlight conditions. A prototype of the Off-axis LFR device was designed and built for assessment, featuring a focus length of just 78 mm and an overall 145 mm housing height. The paper then discusses how the sunlight self-adaptive features enhance the efficiency during the early morning and twilight hours. Comprehensive testing, including mechanical driving, laser focusing, and outdoor full-function verification, was conducted. Ultimately, comparative photo-thermal efficiency tests with a similarly sized conventional LFR concentrator demonstrated that the Off-axis LFR concentrator could achieve a significant increase in efficiency, with an all-day average thermal efficiency improvement of over 10 %. Based on the previous theoretical study, this study has completed the engineering prototype design and validation. And confirmed a thermal concentration efficiency of 44.36 % within a height of 145 mm in experiments.

A Comprehensive analysis of energy, exergy, economic and environment on integrated solarcombined cycle with various HTFs and thermal storage

Energy and exergy analysis are considered as important tools for the thermodynamic assessment of any power plant. The utilization of solar energy in electricity generation is progressively increasing day by day due to various issues associated with conventional power plants. In recent times, solar systems in integration with conventional power plants have emerged as popular and optimal solution. The current integrated solar combined cycle (ISCC) involves integrating a 15 MW linear Fresnel reflector with the existing 328.10 MW combined cycle power plant situated in North India. The proposed study examined the thermodynamic performance (energy and exergy) of ISCC and cascade thermal storage. The exergy loss in solar system, combined cycle, and thermal storage is quantified, followed by a comparative analysis of the impact of integrating the solar system and thermal storage on the exergy loss within the combined cycle plant. The results indicate that the collector-receiver experience the highest exergy loss at 69.41%, which is further reduced by 1.82% and 3.39% by employing therminol oil and molten salt, respectively, in thermal storage within the solar system. Additionally, integration of solar system & thermal storage with conventional system showed improvement in second law efficiency. The overall exegetic efficiency of the power system is improved by 1.38% and 3.12% utilizing molten salt as HTF with two-tank system and cascade TES respectively. CO2 emissions are reduced by 97,020 tons per annum with molten salt, which serves as a superior HTF compared to water. Cascade TES systems reduce a greater amount of CO2 emissions compared to two-tank TES systems, amounting to 172,260 tons per annum.

Advanced eco-friendly power and cooling cogeneration-thermal energy storage utilizing phase change materials and chemisorption in renewable-based configurations

Increasing the reliability, stability, and safety of renewable energy systems depends on the integration of energy storage systems in order to balance energy production and demand. This research introduces an innovative system that combines a chemisorption unit, a phase change material (PCM)-based thermal energy storage (TES) mechanism, and a solar thermal unit with Linear Fresnel Reflectors (LFRs), tailored for residential usage. The system’s performance and dynamics are examined using TRNSYS and MATLAB software tools. Within this system, electricity is produced via a turbine propelled by the pressure differential created by chemical reactions within a chemisorption unit. Concurrently, cooling was facilitated through the ammonia evaporation process within an evaporator. At heat source temperatures between 100–200 °C, the system achieved a maximum electricity output of 2,718.9 W and a cooling rate of 14,601.5 W. The energy efficiency peaked at 46.32 %, and exergy efficiency at 40.78 %. The thermal energy storage component, with a volume of 1.5 m3, achieved a maximum storage capacity of 253.7 kWh. The study shows that higher heat source temperatures enhance production capacity but reduce the coefficient of performance (COP) for cooling by approximately 25 %. Overall, the system demonstrates significant potential for improving the efficiency and reliability of renewable energy systems.

Techno-economic analysis and optimization of 50 MWe linear fresnel reflector solar thermal power plant for different climatic conditions

The climate change crisis is primarily associated with carbon dioxide emissions from fossil fuel-based electricity generation, which significantly contribute to the greenhouse gas effect. The implementation of renewable energy technologies can mitigate environmental impacts and promote a sustainable future. This study aimed to conduct a techno-economic feasibility analysis and optimize performance parameters for a 50 MWe capacity Linear Fresnel Reflector (LFR) concentrated solar power plant for nine stations under various climatic conditions. The analysis was conducted based on Levelized Cost of Electricity (LCOE) and Capacity Factor (CF) to select a suitable Heat Transfer Fluid (HTF) for each station, by varying Solar Multiple (SM) from 1.0 to 6.0 and adjusting Thermal Energy Storage (TES) hours from four to sixteen. The HTFs selected for economically feasible projects at different stations were Hitec Solar Salt, Hitec, and Therminol VP-1. The combination of SM and TES hours was optimized for economic feasibility, targeting a minimum CF of 36 % and a maximum LCOE of 13.0 ¢/kWh. The optimum SM and TES hours were found to range from 2.0 to 5.8 and from six to thirteen, respectively. An LCOE of less than 7.5 ¢/kWh and a CF of more than 80 % was achieved for two stations with SM of 6.0 and TES of 16 h using Therminol VP-1. Stations with annual mean direct normal irradiance values higher than 1500 kWh/m2 and clearness index values over 0.58 are suitable for commercial power plants. This study contributes to achieving the United Nation's sustainable development goals by promoting the use of renewable energy technologies.

Quantifying the Shading Effects of a Small-Scale Rooftop-Installed Linear Fresnel Reflector in Cyprus

Linear Fresnel reflectors are a versatile solar concentration technology, suitable for a wide range of industrial processes and thermal conditioning applications. Such collectors entail a certain footprint, generating shading on the surface where they are installed. This effect is rarely quantified but may play an indirect role on the surface below. When installed on a roof, the solar radiation heats the building less. In places where the annual heating demand is higher than the cooling demand, this constitutes an asset. However, this becomes a disadvantage when the cooling demand is higher annually than the heating demand. Essentially, the reduced solar radiation allows for the growth of plants that would not grow without the shade provided by the collector. The present paper is a quantitative analysis of such shading based on the linear Fresnel reflector of the Cyprus Institute. The work was conducted using the Tonatiuh++ ray-tracing software to determine the annual radiation blocking. A total of four years of actual meteorological measurements were applied directly to the ray-tracing model.

Numerical study on effect of hybrid nanofluid as a passive heat transfer enhancement technique and different climates on thermal performance in a linear Fresnel collector

AbstractA notable distinction in this research is the utilization of a new method for calculating critical heat flux (CHF) based on a Look‐Up Table. The present study comprehensively investigates the effects of hybrid nanofluid, a type of passive heat transfer enhancement technique, on convection heat transfer coefficients and CHF. The study covers five different climates representing significant climate conditions in Iran, namely Bandar Abbas, Esfahan, Shiraz, Tehran, and Yazd, each with different solar irradiations. The nanoparticles considered in this study include silver, nickel, and aluminum, as well as Ag‐Au hybrid nanofluid with volumetric concentrations of 0.1%, 0.3%, 0.5%, 1%, and 2%. The modeling results reveal that the heat transfer coefficient increases with the volumetric concentration of nanoparticles. According to the results, at the CHF point for 2 vol% Ag–Au hybrid nanofluid and Ag, Ni, and Al nanoparticles, the heat transfer coefficient shows an increase of 28%, 11.5%, 10.6%, and 4.9%, respectively, compared to the results for pure water in Shiraz. Despite the acceptable results and effective performance of 2 vol% Ag–Au hybrid nanofluid for a linear Fresnel reflector, economically, 2 vol% nickel nanoparticles are identified as the most suitable choice.

Comparative analysis of machine learning models of linear Fresnel solar collector

Modeling solar plants, like Linear Fresnel Reflectors, plays an essential role in analyzing plant characteristics, assessing overall efficiency, designing appropriate controllers, and optimizing system's operation. Although physical modeling approaches are widely used, their accuracy when compared to real operational data is deficient. In this context, this paper conducts a novel and comprehensive investigation for an existing Linear Fresnel Reflector using six distinct machine learning algorithms namely, Multilayer Perceptron and LSTM Neural Networks, Random Forest, Decision Trees, Extreme Gradient Boosting, and K-Nearest Neighbours to forecast the useable output power of a linear Fresnel solar plant. Datasets between May 2018 and September 2019 with a 30-s time interval from a linear Fresnel plant located in Nicosia, Cyprus are used in this research. Seven distinct statistical metrics, in conjunction with the computation time are employed to assess the performance of the different machine learning models. The objective of this study is to further improve the prediction of Linear Fresnel Reflectors performance using machine learning model, in order to increase modeling reliability on an annual basis. Outcomes reveal that, among the various models considered, K-Nearest Neighbours demonstrated the most optimal performance with a coefficient of determination 98.81 % and a mean absolute percentage error of 1.975 %.

Comparative techno-economic and environmental analysis of a relocatable solar power tower for low to medium temperature industrial process heat supply

The primary objective of this study is to promote the adoption of solar power tower (SPT) technology in low to medium-temperature industrial process heat (IPH) applications and compare it with other heat generation alternatives. Through comprehensive techno-economic and environmental analyses, a proposed relocatable SPT-based IPH plant (PR-SPT-IPH), with a capacity of 1 MWth, is thoroughly evaluated against traditional concentrating solar-thermal power (CSP) technologies like parabolic trough collectors (PTC) and linear Fresnel reflectors (LFR), as well as natural gas (NG) and photovoltaic (PV)-based IPH systems. The techno-economic assessment of the PR-SPT-IPH is performed using an in-house developed MATLAB code, while the system advisor model (SAM) is used to simulate equivalent PTC-, LFR-, and PV-based IPH plants. The primary techno-economic assessment metric is the levelized cost of heat (LCOH), while the environmental analysis quantifies the avoided greenhouse gas (GHG) emissions and other pollutants resulting from NG combustion. The results show that the PR-SPT-IPH plant achieves the lowest LCOH of 2.42 cents/kWhth, generating annual thermal energy of 5.62 GWhth with a capacity factor of 48.27 %. With certain assumptions, this cost can be further reduced to 1.5 cents/kWhth, meeting the U.S. Department of Energy targets. The PR-SPT-IPH plant could annually avoid emitting 1112 kg of CO2, 54 kg of particulate matter, 1201.76 kg of NOx, and 5.08 kg of SO2. It could also save annual external costs between $43,100.28 and $153,194.67, while the annually saved fuel cost could reach $151,632. The study indicates that the PR-SPT-IPH plant surpasses PTC-, LFR-, NG-, and PV-based IPH plants both technically and financially. With reduced capital costs and appropriate incentives, the PR-SPT-IPH plant emerges as an economically and environmentally viable choice for low to medium-temperature IPH applications.

Energy cost optimization of Linear Fresnel Reflector (LFR) systems for different regions of installation

The Linear Fresnel Reflector (LFR) is a promising Concentrating Solar Thermal Power (CSP) technology due to its simplicity and cost-effectiveness. This paper presents a novel method for optimizing the Levelised Cost of Electricity (LCOE) for site-specific LFR systems. The method integrates ray tracing and a thermal model with a genetic algorithm to simulate and optimize LFR designs for three different annual solar irradiance profiles. For an LFR with a standard evacuated tube receiver with a 70 mm diameter, the optimal design variables are determined to be within the ranges of 8.9–9.2 m for receiver height, 18–22 for the number of mirrors, 0.63–0.81 m for mirror width and 0.10–0.13 m for mirror spacing. The results show that the optimized LFR design variables remain relatively consistent across different locations, allowing for the efficient use of one design in multiple locations. A sensitivity analysis shows that the LCOE is predominantly affected by receiver height. Comparing the optimized designs with recent commercial LFR installations reveals that, when 6 hours of thermal energy storage is used, LCOE savings of up to 20% are still achievable. Overall, the study demonstrates that there are still substantial LFR design improvements that can be made to reduce the cost of electricity from an LFR system and make it a cost-competitive solution for clean power generation.

Techno-Economic Assessment of Molten Salt-Based Concentrated Solar Power: Case Study of Linear Fresnel Reflector with a Fossil Fuel Backup under Saudi Arabia’s Climate Conditions

Concentrated solar power (CSP) has gained traction for generating electricity at high capacity and meeting base-load energy demands in the energy mix market in a cost-effective manner. The linear Fresnel reflector (LFR) is valued for its cost-effectiveness, reduced capital and operational expenses, and limited land impact compared to alternatives such as the parabolic trough collector (PTC). To this end, the aim of this study is to optimize the operational parameters, such as the solar multiple (SM), thermal energy storage (TES), and fossil fuel (FF) backup system, in LFR power plants using molten salt as a heat transfer fluid (HTF). A 50 MW LFR power plant in Duba, Saudi Arabia, serves as a case study, with a Direct Normal Irradiance (DNI) above 2500 kWh/m2. About 600 SM-TES configurations are analyzed with the aim of minimizing the levelized cost of electricity (LCOE). The analysis shows that a solar-only plant can achieve a low LCOE of 11.92 ¢/kWh with a capacity factor (CF) up to 36%, generating around 131 GWh/y. By utilizing a TES system, the SM of 3.5 and a 15 h duration TES provides the optimum integration by increasing the annual energy generation (AEG) to 337 GWh, lowering the LCOE to 9.24 ¢/kWh, and boosting the CF to 86%. The techno-economic optimization reveals the superiority of the LFR with substantial TES over solar-only systems, exhibiting a 300% increase in annual energy output and a 20% reduction in LCOE. Additionally, employing the FF backup system at 64% of the turbine’s rated capacity boosts AEG by 17%, accompanied by a 5% LCOE reduction. However, this enhancement comes with a trade-off, involving burning a substantial amount of natural gas (503,429 MMBtu), leading to greenhouse gas emissions totaling 14,185 tonnes CO₂ eq. This comprehensive analysis is a first-of-a-kind study and provides insights into the optimal designs of LFR power plants and addresses thermal, economic, and environmental considerations of utilizing molten salt with a large TES system as well as employing natural gas backup. The outcomes of the research address a wide audience including academics, operators, and policy makers.

Optimal curvature radius of cylindrical mirrors in linear Fresnel reflectors

The optical performance of linear Fresnel reflectors (LFRs) is heavily influenced by the curvature of their cylindrical mirrors. An innovative approach to calculating the optimal curvature radius of cylindrical mirrors in LFRs is introduced. Firstly, an optimization calculation method is proposed to determine the curvature radius of the cylindrical mirror. Then, a universal computational model for the curvature radius of cylindrical mirrors is established. Finally, a detailed analysis is conducted on the impact of optimizing the cylindrical mirrors on the optical performance of LFRs. Optical simulation results indicate that optimizing the curvature radius of the mirror significantly reduces the lateral drift of reflected rays. Increasing slope error, tracking error, and curvature radius error of the cylindrical mirrors result in decreased optical efficiency gain in the optimized LFR while improving uniformity. Furthermore, a larger transversal incidence angle yields a more pronounced improvement in the optimized gain, demonstrating a substantial enhancement in optical efficiency without compromising uniformity in LFRs. The average optical efficiency gain of the LFR is measured at 7.09 %, with an average uniformity loss of 2.10 % under all the studied conditions.

Heat-collecting performance of linear Fresnel reflector concentrator measuring and forecasting after dust accumulation

To quantitatively analyze the influence of dust on the linear Fresnel reflector in different seasons on the thermal performance of the system. In this paper, a two-year outdoor dust accumulation test was carried out, and a quasi-dynamic test method considering dust accumulation factors was adopted to study and predict the influence of dust on the thermal performance of linear Fresnel reflector concentrating system. The results show that for every 1 g/m2 increase in dust density, the relative reflectivity decreases by 4.11 %, and the thermal efficiency decreases 6.96 %. The model prediction shows that when the dust density is 5 g/m2 and the solar radiation is 750 w/m2, the thermal power of the system will decrease by 52.90 % in winter, 26.98 % in summer and 35.30 % in spring and autumn. Therefore, to ensure the efficient operation and economy of the system, in the case of no rain, the dust removal period of the mirror in spring and autumn is 20 days, in summer and winter is 30 days and 10 days respectively.

Design and performance estimate of a novel linear fresnel reflector solar-gas combined system for producing electricity and hydrogen

Multi-energy complementary technology is meaningful for promoting the development of solar energy utilization, and the main novelty of this paper is the proposal of a novel linear Fresnel reflector solar-gas combined (LSGC) system which utilizes the organic Rankine cycle driven proton exchange membrane hydrogen production (PEM-HP) subsystem as well as is designed for generating electricity and hydrogen. By using the Ebsilon, the operation performance and exergy analyses of the LSGC system are launched. The results show that the output power and electric efficiency of the LSGC system are 424.8 MW and 45.4%. The solar field contributes a power of 34 MW. The hydrogen production rate of the LSGC system is 182.88 kg/day. The solar field, GTCC and PEM-HP section can reach the coordinated operation effectively during a long term, revealing the technical feasibility of the LSGC system. The exergy analysis results indicate that the solar field has the second maximum exergy destruction and the smallest exergy efficiency, and the combustion chamber has the maximum exergy destruction. The economic analysis shows that the levelized costs of electricity and hydrogen of the LSGC system are 0.045 $/kWh and 5.67 $/kg. The environment effect evaluation shows that compared with the coal power, the LSGC system can reduce the annual emissions of CO2, NOx, SO2 and dust effectively. Those reveal relatively acceptable economic feasibility and environment protection effect of the LSGC system.

Experimental Investigation of the Influence of Longitudinal Tilt Angles on the Thermal Performance of a Small-Scale Linear Fresnel Reflector

This paper analyses the influence of the longitudinal tilt angle of the secondary system of a low-concentration photovoltaic system based on a small-scale linear Fresnel reflector. Several evaluation indicators, such as useful heat gain, thermal efficiency, incident solar irradiance gain on the photovoltaic cells, and total useful energy gain, were evaluated for five wind speed conditions and six locations in the Northern Hemisphere. The tests were performed with two small-scale linear Fresnel reflector configurations: the classical large-scale linear Fresnel reflector configuration (base configuration) and the optimal longitudinal tilt angle configuration (longitudinal tilt configuration). An experimental platform based on an open-loop wind tunnel was designed and built for this purpose. As far as useful heat production, the longitudinal tilt configuration performs worse as the longitudinal tilt angle and wind speed increase. A useful heat gain 33.91% lower than the base configuration is obtained with a wind speed of 10.03 (m/s) at the 36.86 (°) latitude location. Thermal efficiency decreases with increasing wind speed and longitudinal tilt angle. The thermal efficiency is between 0.3 and 0.2 with wind speeds of 4.99 (m/s) and 10.03 (m/s). The longitudinal tilt configuration shows the best increase in total useful energy gain in the absence of wind (up to 53% at a latitude of 36.86 (°)). This increase is 25% at this same location with a wind speed of 10.03 (m/s). It can be concluded that the effect of the longitudinal tilt of the secondary system has a positive effect. To highlight the importance of this work, the results obtained in the configuration comparison were used to compare a nonconcentrating photovoltaic system and a low-concentration photovoltaic system. The incident solar irradiance on the photovoltaic cells is much higher with nonconcentrating photovoltaic technology. This solar irradiance gain is over 60% for the base configuration and 45% for the longitudinal tilt configuration. The total useful energy gain is 70% in the absence of wind and at the 36.86 (°) latitude location in favour of the low-concentration photovoltaic system. The nonconcentrating photovoltaic system performs better with a wind speed of 10.03 (m/s).

Assessing parabolic trough collectors and linear Fresnel reflectors direct steam generation solar power plants in Northwest México

Concentrating solar power (CSP) systems offer promising solutions for harnessing solar energy. Parabolic trough collectors (PTC) are prevalent in CSP, but direct steam generation (DSG) in solar fields is an innovative alternative that eliminates the need for thermal oils. This study compares EuroTrough PTC and optimized linear Fresnel reflector (LFR) geometries for DSG for Mexican operating conditions. Two 10 MW Rankine cycles with two and three steam extractions are considered. The study evaluates 16 solar field configurations capable of delivering 400 °C superheated steam at 100 bar. Assessment parameters include effective concentration area, nominal loop inlet pressure, energy and exergy efficiency, and hypothetical thermal storage size. The findings strongly favor PTC solar fields with 14 loops, exhibiting superior performance. However, three-loop LFR configurations are suggested where pressure reduction prevails. Three-loop LFR arrays minimize land utilization for spatially constrained installations, while larger five-loop configurations optimize efficiency. Employing 14 PTC loops prioritizes thermal energy storage. In contrast, 8 PTC loops maximize storage capacity. The study underscores the advantages of Fresnel reflectors over parabolic troughs in specific scenarios, presenting avenues for future exploration. This analysis lays the groundwork for assessing these technologies in the distinctive context of Mexican operations, offering valuable insights into sustainable energy applications.

A spectral splitting CPV/T hybrid system based on wave-selecting filter coated compound parabolic concentrator and linear Fresnel reflector concentrator

Efficient full-spectrum solar energy utilization shows great potential to improve solar energy conversion efficiency. In this paper, a spectral splitting concentrated photovoltaic/thermal hybrid system based on a wave-selecting filter-coated compound parabolic concentrator and linear Fresnel reflector mirror field is developed. Optical models to simulate the linear Fresnel reflector have been developed and validated. With the wave-selecting filter coated compound parabolic concentrator, the visible and near infrared spectra transmit onto the photovoltaic cells, while the rest are reflected to the receiver tube. Furthermore, a simplified receiver indoor test prototype is designed to investigate the characteristic of solar photovoltaic module with the spectral filter in the context of the compound parabolic concentrator. The measured I–V curves are compared with the modeled results. Additionally, the thermodynamic performance of the system is analyzed. Parametric studies are performed to investigate the effect of key design parameters including the mirror width, focal length and the radius of the receiver tube on the solar flux density and the exergy efficiency. An exergy efficiency of 35.51% and an optical efficiency of 94.78% are achieved. With a preliminary techno-economic analysis, the levelized cost of the electricity of the system is $0.209/kWh with a payback period of 10 years.

Review of Concentrated Solar Power Technology Applications in Photocatalytic Water Purification and Energy Conversion: Overview, Challenges and Future Directions

Photocatalysis, a promising semiconductor-based technology activated by free and eternal solar energy, has great potential for addressing environmental remediation and energy conversion challenges. Concentrated solar power (CSP) technologies, namely parabolic trough reflectors, solar power towers, parabolic dish reflectors and linear Fresnel reflectors, exhibited excellent feasibility for boosting solar-driven photocatalytic processes. Based on the structural characteristics of CSP technologies, the CSP-based photocatalytic reactors could be divided into concentrated types and non/low-concentrated types. This academic review comprehensively investigated the integration of CSP technology in photocatalysis, emphasizing the feasibility of sunlight as an ideal energy source. Additionally, considering the optimal light irradiance and reaction temperature demands for achieving efficient photocatalytic processes, the significance of introducing CSP into solar light-driven photocatalytic reactions was highlighted. Moreover, the current challenges that exist in CSP-based photoreactors were identified, and potential solutions were proposed accordingly. This work hopes to provide some references for the future study of CSP-based photocatalytic reactors under the theme of sustainable development.

Evaluating energy, exergy and economic aspects of a CO 2 -free Kalina cycle cogeneration system with various solar collectors

Abstract This study meticulously evaluates a Kalina cycle system, adeptly designed for the simultaneous generation of heat, power and cooling. Examining the system from energy, exergy and economic perspectives, the research analyzes the performance of various solar thermal collectors: parabolic trough collectors (PTCs), linear Fresnel reflector, dish-based systems and vacuum tubes (VTs). Among these, the PTC stands out, excelling in energy and exergy efficiency while ensuring cost-effectiveness and minimal system losses. The research also explores the impact of component adjustments on heat, power and cooling production rates. Notably, it identifies the VT collector as the most prominent in terms of exergy destruction and associated costs, with figures reaching 11.07 MW and 159 100 $/year, respectively, offering valuable insights for enhancing the system’s efficiency and economic viability.