Demonstration of Pilot Scale Large Aperture Parabolic Trough Organic Rankine Cycle Solar Thermal Power Plant in Louisiana

During the calendar year of 2012 the University of Louisiana at Lafayette in conjunction with CLECO Power LLC (CLECO) has constructed and commissioned a pilot scale parabolic trough solar thermal power plant for the first time in Louisiana. The large aperture trough (LAT) solar collectors were provided by Gossamer Space Frames and are coupled with an organic Rankine cycle (ORC) power block provided by ElectraTherm, Inc. for study of the feasibility of cost-effective commercial scale solar thermal power production in Louisiana. Supported by CLECO and providing power to the existing CLECO grid, the implementation of state-of-the-industry collector frames, mirrors, trackers, and ORC power block is studied under various local weather conditions which present varied operating regimes from existing solar thermal installations. The solar collectors provide a design output of 650 kWth and preliminary actual performance data from the system level is presented. The optimal size, configuration and location for such a plant in the given solar resource region are being studied in conjunction with CLECO’s search for optimal renewable energy solutions for the region. The pilot scale size of the facility and implementation of the simpler ORC allow remote operation of the facility and flexibility in operating parameters for optimization studies. The construction of the facility was supported by the Louisiana Department of Natural Resources, the U.S. Department of Energy, and CLECO. The continued operation of the plant is supported by CLECO Power LLC and the University of Louisiana at Lafayette.

Modelling of Solar Thermal Power Plant Using Parabolic Trough Collector

The target of the National Solar Mission is to build up India as a worldwide pioneer in solar energy generation. Solar power can be transmitted through grid either from solar photovoltaic or solar thermal technology. As compared to solar photovoltaic, solar thermal installations are less studied, especially regarding energy estimation and performance analysis. For estimating the potential of CSP plants, it is planned to simulate a power plant. We have marginally modified the design of 1 MW operational power plant installed at Gurgaon using Parabolic Trough Collector (PTC) technology. The results are compared with the expected output of Gurgaon power plant and also 50 MW power plant at Rajasthan. Our results have closely matched with a small deviation of 3.1% and 3.6% for Gurgaon and Rajasthan plants, respectively. Our developed model is also validated with 18 different solar power plants in different parts of the world by slightly modifying the parameters according to the plant capacity without changing major changes to the plant design. Difference between our results and the expected energy generation varied from 0.4% to 13.7% with an average deviation of 6.8%. As our results show less than 10% deviation as compared to the actual generation, an attempt has been made here to estimate the potential for the entire nation. For this modelling has been carried out for every grid station of 0.25° × 0.25° interval in India. Our results show that annual solar thermal power plant of 1 MWe capacity potential varies from 900 to 2700 MWh. We have also compared our results with previous studies and discussed.

Effect of SiO_2/B_2O_3 Ratio on the Property of Borosilicate Glass Applied in Parabolic Trough Solar Power Plant

This work aimed to analyze the glass material used for sealing the end of a thermal collector in a parabolic trough solar power plant. Based on matched sealing requirements and application performance of glass and Kovar alloy 4J29, one borosilicate glass material （GD480S）, whose expansion coefficient was similar to that of Kovar alloy 4J29, was studied. Moreover, the effect of the ratio of SiO2 to B203 on the glass properties was explored in detail by Fourier transform infrared spectroscopy. As the SiO2 to B203 ratio in the glass increased from 4.18 to 5.77, the expansion coefficient showed a decreasing trend from 4.95×10-6/℃ to 4.55℃ 10-6/℃. In addition, the water resistance performance improved, enabling the glass material to seal well with the alloy for application in a trough solar power plant. Thus, the increase in the SiO2 to B2O3 ratio made the glass structure more compact and improved the glass performance to meet the requirements of an industrial tubular receiver.

Improving Heat Transfer in Parabolic Trough Solar Collectors by Magnetic Nanofluids

A parabolic trough solar collector(PTSC)converts solar radiation into thermal energy.However,low thermal efficiency of PTSC poses a hindrance to the deployment of solar thermal power plants.Thermal performance of PTSC is enhanced in this study by incorporating magnetic nanoparticles into the working fluid.The circular receiver pipe,with dimensions of 66 mm diameter,2 mm thickness,and 24 m length,is exposed to uniform temperature and velocity conditions.The working fluid,Therminol-66,is supplemented with Fe3O4 magnetic nanoparticles at concentrations ranging from 1%to 4%.The findings demonstrate that the inclusion of nanoparticles increases the convective heat transfer coefficient(HTC)of the PTSC,with higher nanoparticle volume fractions leading to greater heat transfer but increased pressure drop.The thermal enhancement factor(TEF)of the PTSC is positively affected by the volume fraction of nanoparticles,both with and without a magnetic field.Notably,the scenario with a 4%nanoparticle volume fraction and a magnetic field strength of 250 G exhibits the highest TEF,indicating superior thermal performance.These findings offer potential avenues for improving the efficiency of PTSCs in solar thermal plants by introducing magnetic nanoparticles into the working fluid.

Design and Development of a Parabolic Trough Solar Air Heater for a Greenhouse Dryer

Design and Development of a Parabolic Trough Solar Air Heater (PTSAH) for a Greenhouse Dryer (GD) was done to improve the dryer’s performance. The materials used for the fabrication of the PTSAH included galvanized sheets covered with aluminium foil, an absorber tube made of GI pipe painted matt black to increase heat absorbance at the focal line, mild steel square tubes, shutter plywood, and an axial fan to push air through the absorber tube. Key geometrical parameters used for the design of the PTSAH were a rim angle of 98 degrees, focal length of 0.2608 m, height of 0.3451 m, length of 2 m, and an aperture width of 1.2 m. The PTSAH’s total aperture surface area was 2.4 m2, while its absorber tube surface area was 0.1587 m2. The PTSAH was experimentally tested to establish its thermal performance. It was found that the ambient air recorded an average value of 31.1˚C and that the air heater could increase the air temperature by 45.6˚C above ambient with a thermal efficiency of 5.3%. It can, therefore, be concluded that the PTSAH can significantly improve the performance of a GD by supplying the GD with air at a higher temperature than ambient.

Proposal of a Solar Thermal Power Plant at Low Temperature Using Solar Thermal Collectors

To this day, only two types of solar power plants have been proposed and built: high temperature thermal solar one and photovoltaic one. It is here proposed a new type of solar thermal plant using glass-top flat surface solar collectors, so working at low temperature (i.e., below 100°C). This power plant is aimed at warm countries, i.e., the ones mainly located between -40° and 40° latitude, having available space along their coast. This land based plant, to install on the seashore, is technologically similar to the one used for OTEC (Ocean Thermal Energy Conversion). This plant, apart from supplying electricity with a much better thermodynamic efficiency than OTEC plants, has the main advantage of providing desalinated water for drinking and irrigation. This plant is designed to generate electricity (and desalinated water) night and day and all year round, by means of hot water storage, with just a variation of the power delivered depending on the season.

Numerical Model and Performance Validation of a Small-Scale Concentrating Solar Thermal Power Plant in Louisiana

A simplified numerical model of a small-scale (25 - 100 kWe) parabolic concentrating solar power (CSP) plant is presented that can be utilized during the planning stages for a CSP plant, utilizing only simplified information that would be available at the preliminary stages of a project. This is important because existing models currently used for planning purposes, such as the System Advisor Model (SAM) from the National Renewable Energy Laboratory (NREL), do not cover small-scale CSP plants. The model can be used to predict real-time performance, or it can be used with TMY data to estimate annual performance. The model was validated using performance data from an operating small-scale CSP power plant, which is a unique contribution of this work. The results showed that the model correlated well with actual operating measurements for all seasons of the year, and provided a useful tool for planning of future small-scale CSP plants.

Solar Thermal Energy Generation Potential in Gujarat and Tamil Nadu States, India

Government of India has come out with an ambitious target of 100 GW of using solar energy alone by the year 2022. To reach this target, innovative ideas are required to use the solar energy more effectively. For solar electricity generation, mainly two types of technologies are presently in use, namely, solar PV and solar thermal. Being a tropical country, India has large solar PV and solar thermal energy. More research is required on economic aspects to make the solar thermal competitive to solar PV. Towards this direction, in our present study we have simulated a solar thermal power plant using Parabolic Trough Collector (PTC) technology and normalized with 1 MW solar thermal power plant at Gurgaon near New Delhi. Through simulation, we have extended our study and computed the electricity generation possible at different locations of India. For this purpose with 1? × 1?spacing, computations have been carried out at 296 locations. The work is further extended for more detailed study at two representative states, namely, Gujarat and Tamil Nadu. In these two states, closer data points with 0.25? × 0.25? spacing have been considered at 273 locations for Gujarat and 197 locations for Tamil Nadu. Our results indicate a large potential of electricity generation using solar thermal energy in southern states of India, namely, Tamil Nadu, Karnataka, Kerala, southern and western part of Andhra Pradesh and eastern part of Maharashtra. Good potential has also been observed in eastern parts of Gujarat and parts of Madhya Pradesh and eastern part of Rajasthan. The annual potential ranges from 1800 MWh to as much as 2600 MWh. Major parts of northern states, for example Uttar Pradesh, Bihar, West Bengal, Punjab, Jammu and Kashmir have medium range potential. Here, the annual potential ranges from 1000 to 1500 MWh. Poor range of potential is observed towards eastern parts of India and north eastern states. Here, the electricity generation potential ranges from 600 to 1200 MWh. Our results are useful to solar thermal developer and decision managers.

Off-Design Simulation of a CSP Power Plant Integrated with aWaste Heat Recovery System

Concentrating Solar Power(CSP)plants offer a promising way to generate low-emission energy.However,these plants face challenges such as reduced sunlight during winter and cloudy days,despite being located in high solar radiation areas.Furthermore,their dispatch capacities and yields can be affected by high electricity consumption,particularly at night.The present work aims to develop an off-design model that evaluates the hourly and annual performances of a parabolic trough power plant(PTPP)equipped with a waste heat recovery system.The study aims to compare the performances of this new layout with those of the conventional Andasol 1 plant,with the aim of assessing the improvements achieved in the new design.Based on the results,it can be concluded that the new layout has increased the annual generated power to almost 183 GWh(an increase of about 7.60% is achieved compared to the Andasol 1 layout that generates 169 GWh annually).Additionally,the proposed installation has achieved an efficiency of 20.55%,which represents a 7.87% increase compared to the previous design(19.05%).The Levelized Cost of Electricity(LCOE)of the new layout has been reduced by more than 5.8% compared to the Andasol 1 plant.Specifically,it has decreased from 13.11 to 12.35 c/kWh.This reduction in LCOE highlights the improved cost-effectiveness of the newlayout,making it amore economically viable option for generating electricity compared to the conventional Andasol 1 plant.

Potential Map for the Installation of Concentrated Solar Power in Northeast of Brazil Using Analytic Hierarchy Process (AHP)

Brazil has a predominantly renewable energy matrix, with large participation of water resource in domestic supply of energy. Data from 2019 National Energy Balance show that renewable sources (water, biomass, wind and solar photovoltaic) together represented 83% of domestic electric supply in 2018, where the remaining percentage (16.7%) represented non-renewable sources. The generation of electricity through thermal solar technology was not representative. However, it is known that Brazil presents high potential for the installation of solar thermal plants, especially in the Northeastern Region, where direct normal solar irradiation values are high. It is observed that the (high) costs of the projects associated to the absence of a specific incentive program make Concentrating Solar Power (CSP) plants installation more and more time consuming. As a way to contribute to the insertion of solar thermal energy in Brazil, this article presents a methodology for the location of parabolic trough solar thermal plants of 80 MW for the State of Bahia, located in the Northeastern Region of Brazil. Such methodology was based on the application the Analytic Hierarchy Process (AHP) method and the Geoprocessing Technologies to define potentially available sites for the implementation of the projects. For the analysis, parameters related to energy production in the solar power plant, electric, roadways and water infrastructure of the plant were taken into account, as well as the occupation, slopes and land use. Considering the analyses performed, it was confirmed that Bahia disposes of many sites with great generation potential, especially in the western region of the State (at Barreiras), where favorable conditions were found for the development of the technology. Localities situated in other region of the State were also confirmed as suitable, however with less site availability for the insertion of plants. Methodology validations were also carried out and indicated that the model reached the proposed objective, faithfully representing the real-world simplifications that were made.

Preliminary Design Study on Concentrated Solar Power PVRs to Operate with RCBC

Parabolic through concentrators and parabolic dish concentrators followed by a PVR （pressurized volumetric receiver） are proposed, studying the performance behavior of a RCBC （regenerative closed Brayton cycle） operating with helium or hydrogen. A pressurized gas such as helium circulates along the volumetric receiver, capturing the concentrated thermal solar energy to be further converted into electric power via a thermal cycle. The overall efficiency of the plant has been computed under variable parameters to determine the operating conditions for which efficiency and specific power are acceptable. As consequence of the proposed analysis, it is concluded that direct coupling between volumetric receivers and thermal engines renders high efficiency while avoiding an intermediate heat transfer medium.

Potential of performance improvement of concentrated solar power plants by optimizing the parabolic trough receiver

This paper proposes a comprehensive thermodynamic and economic model to predict and compare the performance of concentrated solar power plants with traditional and novel receivers with different configurations involving operating temperatures and locations.The simulation results reveal that power plants with novel receivers exhibit a superior thermodynamic and economic performance compared with traditional receivers.The annual electricity productions of power plants with novel receivers in Phoenix,Sevilla,and Tuotuohe are 8.5%,10.5%,and 14.4%higher than those with traditional receivers at the outlet temperature of 550℃.The levelized cost of electricity of power plants with double-selectivecoated receivers can be decreased by 6.9%,8.5%,and 11.6%.In Phoenix,the optimal operating temperature of the power plants is improved from 500℃to 560℃by employing a novel receiver.Furthermore,the sensitivity analysis of the receiver heat loss,solar absorption,and freeze protection temperature is also conducted to analyze the general rule of influence of the receiver performance on power plants performance.Solar absorption has a positive contribution to annual electricity productions,whereas heat loss and freeze protection temperature have a negative effect on electricity outputs.The results indicate that the novel receiver coupled with low melting temperature molten salt is the best configuration for improving the overall performance of the power plants.

Modelling and analysis of an 80-MW parabolic trough concentrated solar power plant in Sudan

Concentrated solar power plants can play a significant role in alleviating Sudan’s energy crisis.These plants can be established and implemented in Sudan,as their potential is considerably high due to the climate conditions in Sudan.This study investigates the design of a parabolic trough concentrated solar power plant in Sudan and analyzes its technical and economic feasibility.The simulation of the plant’s model used System Advisor Model(SAM)software.To determine the best location for the construction of the plant,data from 15 cities in Sudan were compared with each other based on their solar radiation and land properties.Wadi Halfa,a city in the northern region of Sudan,was chosen as the location due to its good topographical properties and climate conditions.The results show that the proposed plant can generate 281.145 GWh of electricity annually with a capacity factor of 40.1%and an overall efficiency of 15%.Additionally,a simple cost analysis of the plant indicates a levelized cost of electricity of 0.155$/kWh.As the study results are consistent with the characteristics of similar plants,the proposed plant is considered technically and economically feasible under the conditions at its location.

Comprehensive Review of Line-Focus Concentrating Solar Thermal Technologies: Parabolic Trough Collector (PTC) vs Linear Fresnel Reflector (LFR)

In the present review,parabolic trough collector(PTC)and linear Fresnel reflector(LFR)are comprehensively and comparatively reviewed in terms of historical background,technological features,recent advancement,economic analysis and application areas.It is found that although PTC and LFR are both classified as mainstream line-focus concentrating solar thermal(CST)technologies,they are now standing at different stages of development and facing their individual opportunities and challenges.For PTC,the development is commercially mature with steady and reliable performance;therefore,extension of application is the main future demand.For LFR,the development is still in rapid progress to commercial maturity,yet indicating very promising potentials with high flexibility in novel designs and remarkable reduction in capital and operational costs.The question,which has to be answered in order to estimate the future perspectives of these two line-focus CST technologies,becomes which of these characteristics carries more weight or how to reach an optimal trade-off between them.

Characteristics of the transient thermal load and deformation of the evacuated receiver in solar parabolic trough collector

As a core element in solar parabolic trough collector, the evaluated receiver often runs under severe thermal conditions. Worse still, the transient thermal load is more likely to cause structural deformation and damage. This work develops an efficient transient multi-level multi-dimensional(M2) analysis method to address photo-thermal-elastic problems, thereby estimating transient thermal load and deformation for the receiver:(i) one-dimensional(1-D) thermo-hydraulic model is adopted to determine the transient thermo-hydraulic state,(ii) 3-D finite volume method(FVM) model for the receiver tube is established to obtain the real-time temperature distribution,(iii) 3-D finite element method(FEM) model is employed to make thermoelastic analysis. Based on this M2 method, the typical transient cases are conducted in cold-start, disturbed-operation and regulatedprocess. Three indicators(average temperature of the wall(ATW), radial temperature difference(RTD), circumferential temperature difference(CTD)) are defined for overall analysis of the receiver thermal load. It is found that in the transient process,receivers face response delay and endure significant thermal load fluctuation. The response time for a single HCE(heat collecting element) under lower mass flow rate(1.5 kg s-1) could sustain 280 s. During the cold-start stage(DNI=200 W m-2 to 800 W m-2), the maximum value of CTD in receiver is as high as 11.67℃, corresponding to a maximum deflection of 1.05 cm.When the mass flow rate decreases sharply by 80%, the CTD reaches 33.04℃, causing a 2.06-cm deflection. It should be pointed out that in the cold-start stage and the lower mass flow rate operation for solar parabolic trough collector, alleviating the transient thermal load and deformation is of importance for safely and efficiently running evaluated receiver.

Increasing Coal-Fired Power Plant Operational Flexibility by Integrating Solar Thermal Energy and Compressed Air Energy Storage System

This paper proposed a novel integrated system with solar energy,thermal energy storage(TES),coal-fired power plant(CFPP),and compressed air energy storage(CAES)system to improve the operational flexibility of the CFPP.A portion of the solar energy is adopted for preheating the boiler’s feedwater,and another portion is stored in the TES for the CAES discharging process.Condensate water from the CFPP condenser is used for cooling compressed air during the CAES charging process.The thermodynamic performance of the integrated system under different load conditions is studied.The system operations in a typical day are simulated with EBSILON software.The system enables daily coal saving of 9.88 t and reduces CO_(2)emission by 27.95 t compared with the original CFPP at 100%load.Under partial load conditions,the system enables maximum coal saving of 10.29 t and maximum CO_(2)emission reduction of 29.11 t at 75%load.The system has maximum peak shaving depth of 9.42%under 40%load condition.The potential of the system participating ancillary service is also discussed.It is found that the integration of solar thermal system and CAES system can bring significant ancillary service revenue to a conventional CFPP.

Thermal and hydraulic characteristics of a large-scaled parabolic trough solar field (PTSF) under cloud passages

To better understand the characteristics of a large-scaled parabolic trough solar field(PTSF)under cloud passages,a novel method which combines a closed-loop thermal hydraulic model(CLTHM)and cloud vector(CV)is developed.Besides,the CLTHM is established and validated based on a pilot plant.Moreover,some key parameters which are used to characterize a typical PTSF and CV are presented for further simulation.Furthermore,two sets of results simulated by the CLTHM are compared and discussed.One set deals with cloud passages by the CV,while the other by the traditionally distributed weather stations(DWSs).Because of considering the solar irradiance distribution in a more detailed and realistically way,compared with the distributed weather station(DWS)simulation,all essential parameters,such as the total flowrate,flow distribution,outlet temperature,thermal and exergetic efficiency,and exergetic destruction tend to be more precise and smoother in the CV simulation.For example,for the runner outlet temperature,which is the most crucial parameter for a running PTSF,the maximum relative error reaches−15%in the comparison.In addition,the mechanism of thermal and hydraulic unbalance caused by cloud passages are explained based on the simulation.

Dynamic simulation and parametric influence analysis on thermal performance of a quartz tube solid particle receiver in solar tower power plants

Due to a higher operating temperature(≥800 ℃),Solar Particle Receiver(SPR)which uses particles as the working medium is considered as one of best candidates to improve the thermoelectric conversion efficiency of concentrating solar power plants.In this paper,a quartz tube solid particle receiver model is fully developed by using the discretized lumped parameter method,in which the calculation process of particle temperature and thermal loss is clearly given.In order to improve the manipulation level of particle receiver during the operation,the dynamic characteristics of the quartz tube particle receiver are comprehensively studied by the disturbance test of selected input parameters.Besides,in order to grasp the influence rule of key parameters on the thermal performance of particle receiver,the key parameters'sensitivity analysis is also deeply studied.The results show that the particle outlet temperature can reach as high as 810 ℃ under a relatively small value of solar flux 600 kW/m^(2),but the receiver efficiency is only about 75%;Besides,the receiver efficiency shows a variation tendency that it rises first falls afterwards with the increase of incident solar flux.The validity of proposed model is verified by a heating experi-mental system with a single quartz tube,and the relative error is not more than 7.9%.The research results are beneficial for understanding the dynamic characteristics and designing the particle receiver.

Performance Evaluation of Short Parabolic Trough Collectors Integrated with a Small-Scale Solar Power and Heating System

An investigation is presented on the performance of a small-scale solar power and heating system with short parabolic trough collectors(PTCs). The steady-state model of the short PTCs is evaluated with outside experiments. The model mainly contains the heat loss of the receiver, the peak optical efficiency and the incident angle factor consisting of incident angle modifier and end loss. It is found that the end loss effect is essential in this model when the length of the PTCs is less than 48 m, especially in the winter. The standard deviation of the steady-state model is 1.4%. Moreover, the potential energy efficiency ratio of the solar power and heating system is considerably larger than the coefficient of performance(COP) of general air-source heat pumps, and increases with the decrease of the condensation temperature. An overall system efficiency of 49% can be reached. Lastly,the existence of a water storage tank improves the flexibility of heating the building, and the volume of the water storage tank decreases with the increase of the heating water temperature.

Operation Strategy Analysis and Configuration Optimization of Solar CCHP System

This paper proposed a new type of combined cooling heating and power(CCHP)system,including the parabolic trough solar thermal(PTST)power generation and gas turbine power generation.The thermal energy storage subsystem in the PTST unit provides both thermal energy and electrical energy.Based on the life cycle method,the configuration optimization under eight operation strategies is studied with the economy,energy,and environment indicators.The eight operation strategies include FEL,FEL-EC,FEL-TES,FEL-TES&EC,FTL,FTL-EC,FTL-TES,and FTL-TES&EC.The feasibility of each strategy is verified by taking a residential building cluster as an example.The indicators under the optimal configuration of each strategy are compared with that of the separate production(SP)system.The results showed that the PTST-CCHP system improves the environment and energy performance by changing the ratio of thermal energy and electric energy.The environment and energy indicators of FEL-TES&EC are superior to those of FTL-TES&EC in summer,and the results are just the opposite in winter.The initial annual investment of the PTST-CCHP system is higher than that of the SP system,but its economic performance is better than that of the SP system with the increase of life-cycle.