Trough Solar Thermal Power Plant Research Articles

The Simulator of China General Nuclear Power Group (CGNPC) Delingha 50 MW Parabolic Trough Solar Thermal Power Plant

CGN Delingha 50MW parabolic trough solar power plant is China's first commercial trough solar power station. There are 190 heat collecting loops in the solar field of the power plant. Due to the mutual coupling of heat collecting loops layout location, environmental conditions, medium flow, working medium physical property changes and other factors, the hydrodynamic characteristics of the solar field are complex. In practical operation, balancing the flow of the heat absorbing medium in each loop of the large-scale trough solar thermal power plant and stabilizing the outlet medium temperature are difficult problems. Taking CGN Delingha 50MW parabolic trough solar power plant as the research object, this paper adopts the idea of modular modeling to establish the mathematical model of the main equipment in different systems of the power plant, to build the dynamic model of its solar field, steam generation system, heat storage system and steam turbine system. Based on the parallel computing function of the real-time dynamic simulation platform STAR-90, the real-time coupling calculation between different systems is realized. The error of the built model in steady-state is less than 2%, and the dynamic results of the model are in good agreement with the actual operation data. The modeling method in this paper is universal and can be a reference for dynamic modeling of other large-scale trough solar thermal power plants.

Techno-economic feasibility analysis of a large-scale parabolic trough thermal power plant in Effurun-Warri, Nigeria

Abstract 
 In the modern world, solar energy is one of the most mature renewable energy resources for electricity generation. Because of the growing interest in green energy and CO2 reduction, concentrated power technologies have gained prominence all over the world. Several parabolic trough power plants are currently operational in various parts of the world. However, despite the region's favorable weather conditions, Nigeria and Sub-Saharan Africa have yet to adopt this technology. To galvanize the integration of solar energy into the energy infrastructure in Nigeria, technical and economic feasibility studies are required. This paper presents a techno-economic viability assessment of a 25 MW Parabolic Trough solar thermal power plant for electricity generation in Effurun-Warri, Nigeria. The System Advisor Model (SAM) software was used for the analysis, based on the validated technical and financial models inbuilt into the software. Results showed that the plant is technically feasible in Effurun-Warri with a capacity factor of over 35%, which compares favourably with other similar plants across the globe. However, the levelized cost of electricity (LCOE) of 11.87 cents/kWh obtained is significantly higher than the subsidized cost of electricity in the country, by about 99%, leading to a negative net present value of the project. To improve cost, optimized design parameters of the plant should be adopted for performance simulation in the SAM software.

Design, commissioning and operation of a mini hybrid parabolic trough solar thermal power plant for direct steam generation

Parabolic Trough Collectors (PTCs) are the most mature, reliable and widespread among Concentrated Solar Power (CSP) technologies for electricity generation. The conventional power plants relying on PTCs use synthetic oil as Heat Transfer Fluid (HTF) which has limited life span, has limited operation temperature, is expensive and harmful to the environment. In the present research work, a new perspective has been developed to directly generate steam in the collectors, eliminating the need for HTF in the solar field and avoiding auxiliary heat exchangers. A mini hybrid Direct Steam Generation PTC power plant having a boiler as a backup that can be operated with biogas or natural gas is installed at Ecole Nationale d'Ingénieurs de Tunis (ENIT) within the framework of REELCOOP project (Renewable ELectricity COOPeration). The description, commissioning and operation of the solar plant are presented in this paper. The plant is designed and tested under real-life operating conditions in the south Mediterranean region. The feasibility of the DSG process in horizontal parabolic trough collectors has been confirmed and an important know how has been acquired regarding the operation of DSG solar plant. The main instructions for the operation of the solar plant have been presented including start-up and shutdown procedures of the plant, as well as the safety measures to be considered.The development of this plant is aimed to address the challenge of coupling intermittent solar radiation and the presence of a two-phase fluid in the absorber tubes. An important know how has been acquired regarding the operation of DSG solar plants in solar only mode and in hybrid mode which allowed to balance strengths and weaknesses of solar and biogas/natural gas technologies. By combining both systems, we have tackled the problem of the controllability of the energy supply while exploiting as much as possible renewable sources.

Study on dynamic model and dynamic characteristics of Delingha 50 MW trough solar field

China General Nuclear Power Group (CGNPC) Delingha 50 MW parabolic trough solar thermal power plant is the first commercial trough solar plant in China, and its solar field consists of 190 parallel heat collecting loops. For large-scale trough solar plant, balancing the flow rate of heat absorbing medium in each loop and stabilizing the outlet temperature are the key technologies and difficult problems. Regarding the Delingha 50 MW solar field as the research object, this paper mainly focusing on the dynamic characteristics of flow and heat transfer in the solar field. The hydrodynamic calculation model and the heat transfer dynamic model are established on the real-time dynamic simulation platform STAR-90. With the actual operation data, the built solar field model is validated by comparing the simulation results. On this basis, the disturbance simulations of direct normal irradiance (DNI), heat transfer oil’s mass flow and heat transfer oil’s inlet temperature are carried out. The dynamic response curves of disturbance and the thermal inertia time constant of the loops are obtained. The conclusions lay a theoretical foundation for the formulation of outlet medium’s temperature control strategy in the solar field of large-scale trough solar thermal power generation system.

Study on Dynamic Model and Dynamic Characteristics of Solar Field of 50 Mw Trough Solar Thermal Power Generation Plant

Solar thermal power generation solves the problem of fluctuation and intermittency through energy storage system, and can bear the basic power load and peak load regulation. It is an important technical way for China's energy structure transformation. As a complex thermal system with multivariable disturbance, large inertia and large delay, the operation control of the solar field is a difficult issue. In this paper, the solar field of the first 50 MW trough solar thermal demonstration power plant in China is taken as the research object. Based on the topological structure and working principle of the solar field and the basic laws of optics and thermodynamics, the hydrodynamic calculation model and the heat transfer dynamic model are developed. The correctness of the model is verified by comparing the simulation results with the actual operation data. On this basis, the disturbance simulations are carried out. In addition, the dynamic response curves of step disturbance and the inertia time constant of the heat collecting loops are obtained. The conclusions of this paper have important guiding significance for the operation control strategy formulation and system optimization design of trough solar thermal power generation system.

Simulation and optimization of a Concentrating Solar Power Plant with Thermal Energy Storage in Sebha city by using system advisor model (SAM)

Concentrated solar power (CSP) is viewed as one of the most promising alternatives in the field of solar energy utilization; parabolic trough collector (PTC) solar power plants are the most commercially established among the power plants operating with CSP technology. In this paper, a parabolic trough solar thermal power plant with thermal energy storage was evaluated in terms of design and thermal performance, using the SAM program of NREL (System Advisor Model). This program is used to evaluate the active and economic performance of a plant such as monthly energy production, annual energy production, and level cost of energy (LCOE).one representative site in south Libya, Sebha city, which offers an annual average direct normal radiation (DNI) of more than 6.0 kWh/m2/day, has been chosen for the analysis and optimization of the proposed 100 MWe PTC Solar power plant. The optimization is carried out with solar multiple (SM) and full load hours of thermal energy storage TES as the parameters, to minimize the Levelized cost of electricity and maximize the annual energy yield. Based on the findings of the study, the proposed 100 MW PTC solar power plant with thermal energy storage can contribute to the sustainable energy future of Libya with reduced dependency on fossil fuels. This design and performance analysis of the plant encourages further development and innovation of solar thermal power plants in all regions of Libya.

Analysis of the Applicability of the Parabolic Trough Solar Thermal Power Plants in the Locations with a Temperate Climate

Currently, intensive work is underway in Poland to increase the share of renewable energy sources in the overall energy balance. Therefore, this paper presents the possibilities of using concentrated solar power in zones with a temperate climate. A simplified model based on the energy balance in the solar collectors considering the main operating parameters of the typical solar power plant was developed. It should be noted here that the model does not take into account issues related to heat accumulation and electricity generation in a Solar Thermal Power Station. The simulation of forced convection inside the solar collector absorber was additionally included in the calculations to improve its accuracy. The model was verified using actual heat measurements at the outlet of the parabolic collector installation at a Solar Thermal Power Station located in the south of Spain. The heat generated by a similar solar collector system in a selected region with a temperate climate, the city of Bialystok (north-eastern Poland, geographic coordinates: 53°08′07″ N 23°08′44″ E) was determined by the developed simplified model for different months of the year. Based on the results of the analysis, it was found that the energy obtained from the same area of concentrated solar collectors located near Bialystok is eight times lower compared to the location in Cordoba depending on the variant of the power plant operation.

Parabolic Trough Solar Thermal Power Plant with Energy Storage System

Parabolic Trough Solar Thermal Power Plant with Energy Storage System

Estimation of the energy production of a parabolic trough solar thermal power plant using analytical and artificial neural networks models

The accurate estimation of a concentrated solar power plant production is an important issue because of the fluctuations in meteorological parameters like solar radiation, ambient temperature, wind speed, and humidity. In this work, three models were conducted in order to estimate the hourly electric production of a parabolic trough solar thermal power plant (PTSTPP) located at Ain Beni-Mathar in Eastern Morocco. First, two analytical models are considered. The first analytical model (AM I) is based on calculating the heat losses of parabolic trough collectors (PTCs), while the second analytical model (AM II) is based on the thermal efficiency of PTCs. The third model is an artificial neural networks (ANN) model derived from artificial intelligence techniques. All models are validated using one year of real operating data. The simulation results indicate that the ANN model performs much better than the analytical models. Accordingly, the ANN model results show that the estimated annual electrical energy is about 42.6 GW h/year, while the operating energy is approximately 44.7 GWh/year. The frequency of occurrence shows that 86.77% of hourly values were estimated with a deviation of less than 3 MW h. The developed ANN model is readily useable to estimate energy production for PTSTPP.

The energy future of Saudi Arabia is not batteries and photovoltaic solar panels

Recently, North European academics claimed that “Saudi Arabia can accomplish a 100% renewable energy by 2040 that is overwhelmed by PV single-axis following and battery storage”. They moreover say “Battery capacity contributed up to 30% of the full power request in 2040 and the commitment increments to 48% by 2050”. Based on geology, climate conditions, and resources of Saudi Arabia, it is clarified as batteries and photovoltaic solar panels are not the best choice for the country’s energy sector. To cover all the energy supply of Saudi Arabia by solar photovoltaic, plus battery capacity to compensate for the solar energy fluctuations, and unpredictability, is not convenient, for both the economy and the environment. Superior results for the environment and the economy may be accomplished by valorising the fossil fuel assets, through the development of high-efficiency plants such as the combined cycle gas turbine plants of Qurayyah, the advancement of innovations for the generation of clean power, counting oxyfuel combustion and carbon capture and storage, and also developing nuclear energy. The development of nuclear power plants may be more advantageous to the economy and the environment than photovoltaic and batteries. Concerning solar energy, parabolic trough solar thermal power plants also along the coast have advantages versus solar photovoltaic, as thermal energy storage could provide dispatchability. Additionally, a centralized power plant works better than many rooftops photovoltaic that will be likely covered by sand, rusted, or cracked after a few years.

Enclosed trough solar thermal power plant with thermal energy storage and saltwater condenser in Al Khobar, Kingdom of Saudi Arabia

The preliminary design of a concentrated solar power (CSP) plant with thermal energy storage (TES) in Al-Khobar, Kingdom of Saudi Arabia is here presented. The specific conditions, in terms of environment, weather and sun irradiance, sand and dust, humidity, temperature, solar irradiance, clouds coverage, and proximity to the sea, are considered. A CSP parabolic trough (PT) with TES in a glass enclosure and a once-through saltwater condenser is selected to produce solar energy with the added value of dispatchability. The results of the simulation by using the System Advisor Model (SAM) software are proposed in detail. The manuscript presents the supporting experimental data, and the model development, validation, and application. The computation of the operation of a reference CSP PT with TES plant located in a drastically different environment, requiring specific components such as a glass enclosure and a once-through saltwater condenser, is trustworthy. A small-scale pilot plant is however suggested before moving to full-scale plant construction.

Performance analysis of an improved 30 MW parabolic trough solar thermal power plant

As a promising application of solar energy, parabolic trough solar thermal power generation technology is one of the most important methods of solar thermal utilization. This paper takes the SEGS VI parabolic trough plant as the research object and proposes an improved 30 MW parabolic trough solar thermal power plant. An optimization model is established for the overall plant efficiency, and the design of the solar field of the improved plant is presented with an explanation in this paper. This paper uses the commercial software Ebsilon to establish the simulation models of the SEGS VI Plant and the improved plant and conducts a performance analysis of the two plants under design and operating conditions. The results show that the improved plant based on sectional heating can reduce the average working temperature of the thermal oil. The solar field efficiency increases by 0.52% and the overall plant efficiency increases by 0.24% under the design conditions. The daily mean solar field efficiency data increase by 0.53%, and the overall plant efficiency increases by 0.22% under operating conditions. Simultaneously, the number of collectors in the solar field also decreases, which has good application prospects.

Techno-Economic Optimization of Molten Salt Concentrating Solar Power Parabolic Trough Plants With Packed-Bed Thermocline Tanks

Abstract This study focuses on the techno-economic optimization of direct molten salt parabolic trough solar thermal power plants (STPPs) equipped with thermocline filler (TCF) thermal energy storage (TES). On one hand, this technology allows for cost reductions compared with state of the art two-tank (2T) TES. On the other hand, however, it leads to a performance decrease of the power block (PB) due to partial part load operation. To evaluate the dominating effect, annual simulations on a system level are performed for the TCF direct molten salt storage concept and, as a reference, for the two-tank direct molten salt storage concept. The levelized cost of electricity (LCOE) serves as a global measure to compare the two systems and to optimally size the TCF storage and the solar field (SF). The result of this study is that LCOE can theoretically be reduced by up to 8% by using a TCF instead of 2T storage system. The influence of temperature deviations from the nominal value at the end of charge or discharge, porosity and particle diameter of the TCF on LCOE, and system behavior is investigated in detail. This study further presents alternative operation strategies with improved system behavior and reveals determining factors for the integration of TCF storage into a system.

The effect of dust accumulation on the cleanliness factor of a parabolic trough solar concentrator

Solar reflectors are exposed to outdoor environments where dust accumulation is a primary degrading factor on optical performance. In this study, the effect of dust accumulation on reflectivity at different positions on the reflector of a parabolic trough solar thermal power plant in Hohhot, China was investigated and analyzed. The physical and chemical properties of dust accumulation were tested using a combination of spectrophotometer, scanning electron microscopy, and X-ray diffraction. The results showed that dust accumulation on the bottom edge of the reflector caused the largest decrease in reflectivity compared to dust on the center and top edge. In addition, dust particles at Hohhot were dominated by quartz (SiO2, 53.5%), followed by calcium oxide (CaCO3, 25.4%), and some minor feldspar minerals (NaAlSi3O8, 21.1%). However, some characteristics of the dust could not be determined by experimental measurements. To address this gap, a physical model was proposed to predict the impact of dust accumulation on light reflectivity of the reflector. Different physical parameters of the model are discussed, such as the size of the particles, diaphaneity, the incidence light angle, and tilt angle. The maximum relative deviation between the mathematical model and the experimental results was only 1%.

Optimal Start-up Policies for a Nanofluid-Based Solar Thermal Power Plant

Parabolic trough solar thermal power plants use a fluid to transfer thermal energy from captured solar radiation to a Rankine cycle to drive a turbine that, coupled to an electrical generator, produces electricity. Continuous improvement on their performance will lead these technologies to truly compete with either conventional or other forms of renewable energy systems. Nanofluids have been proposed as a way to improve heat transfer rates in thermal solar plants. Hence, nanofluid thermal solar plants coupled to dynamic optimal operating policies should render improved heat transfer characteristics as well as power production. The main objective of this work is to obtain optimal start-up policies of such plants using diverse nanofluids (Al2O3-water and TiO2-water) compared against pure water as base fluid, focused on power delivery and the time required for the system to reach target conditions. For the analysis, the deterministic dynamic mathematical model of a previously proposed solar thermal power fac...

Parabolic trough solar thermal power plant Noor I in Morocco

To go hand in hand with the development of the country and face the rapidly increasing energy demand, Morocco began developing a green plan in order to produce 2000 MW of renewable energy on the horizon of 2020. Solar conversion is believed to play a pivotal role in the Moroccan energy transition. The principle objective of this work is to comprehensively overview the Moroccan parabolic trough solar thermal power plant Noor 1 as one of the leading solar plants in Africa and Middle-East. The main motivations behind the site selection as well as a detailed technical description of the plant are provided. For the first time, existing similar parabolic trough solar thermal power plants worldwide are reviewed and compared. It was concluded that the specific energy generation of Noor 1 is well ranked among the compared plants (superior to 61.5% of other plants).

Optimal Operation Strategies into Deregulated Markets for 50 MWe Parabolic Trough Solar Thermal Power Plants with Thermal Storage

The evolution of electric generation systems, according to relevant legislation, allows for the parallel evolution of the installed power capacity of renewable resources with the development of technologies for renewable resources, therefore optimizing the choice of energy mix from renewable resources by prioritizing the implementation of concentrating solar thermal plants. Thanks to their great potential, parabolic trough solar thermal power plants have become the most widely spread type of electricity generation by renewable solar energy. Nonetheless, the operation of the plant is not unique; it must be adapted to the parameters of solar radiation and market behavior for each specific location. This work focuses on the search for the optimal strategies of operation by a mathematical model of a 50 MWe parabolic trough thermal power plant with thermal storage. The analysis of the different ways of operation throughout a whole year, including model verification via a currently operating plant, provides meaningful insights into the electricity generated. Focused to work under non-regulated electricity markets to adjust this type of technology to the European directives, the presented model of optimization allows for the adaptation of the curve of generation to the network demands and market prices, rising the profitability of the power plant. Thus, related to solar resources and market price, the economic benefit derived from the electricity production improves between 5.17% and 7.79%.

Numerical analysis of magnetic field effects on the heat transfer enhancement in ferrofluids for a parabolic trough solar collector

A parabolic trough is defined as a type of solar thermal collector that is straight in one dimension and curved as a parabola in the other two, lined with a polished metal mirror. Enhancing the thermal efficiency of this collectors is one of the major challenges of developing and growing of parabolic trough solar thermal power plants. Ferrofluids were proposed as a novel working fluid for industrial applications, due to their thermal performances. In this study, the convective heat transfer of Fe3O4-Therminol 66 ferrofluid under magnetic field (0–500 G) is evaluated using computational fluid dynamics. The ferrofluid with different volume fraction (1–4%) and the Therminol 66 (as the base fluid) are considered as the working fluids for a parabolic trough solar collector. Numerical analysis first validated using theoretical results, and then a detailed study is conducted in order to analyze the effect of the magnetic field on different parameters. The result demonstrated that using magnetic field can increase the local heat transfer coefficient of the collector tube, thermal efficiency as well as output temperature of the collector. In addition, increasing the volume fraction of nanoparticle in the base fluid and intensity of magnetic field increased the collector performance.

Performance and Simulation of a Stand-alone Parabolic Trough Solar Thermal Power Plant

In this paper, a Simulink® Thermolib Model has been established for simulation performance evaluation of Stand-alone Parabolic Trough Solar Thermal Power Plant in Universiti Teknologi PETRONAS, Malaysia. This paper proposes a design of 1.2 kW parabolic trough power plant. The model is capable to predict temperatures at any system outlet in the plant, as well as the power output produced. The conditions that are taken into account as input to the model are: local solar radiation and ambient temperatures, which have been measured during the year. Other parameters that have been input to the model are the collector’s sizes, location in terms of latitude and altitude. Lastly, the results are presented in graphical manner to describe the analysed variations of various outputs of the solar fields obtained, and help to predict the performance of the plant. The developed model allows an initial evaluation of the viability and technical feasibility of any similar solar thermal power plant.

An integrated program of a stand-alone parabolic trough solar thermal power plant: Code description and test

Solar thermal systems produce steam after being energized by solar parabolic trough concentrators, are incorporated with a steam turbine-generator assembly to produce electricity. This study presents a code for prediction of performance, while under-taking preliminary plant-sizing for a variety of parabolic trough solar fields operating under nominal conditions. The code, named as PTPPPP (Parabolic Trough Power Plant Performance Predictor) consists of four blocks. The code allows prediction of variables including: heat loss coefficient, UL, aperture effective direct normal irradiance, I, heat gain, Qgain, and the thermal efficiency of stand-alone parabolic trough solar thermal power plant in commerce, ηp. The conceptual design of the stand-alone parabolic trough solar involves: selection and sizing of system components, power generation cycles, working fluid types, and power block sizing. The input weather parameters and the operational parameters to the code have been acquired from in-situ measurements. The prediction results of the code have been found in good agreement with literature data with mean error of 0.18% in prediction of output power. In addition, this code is able to provide a flexibility in terms of temperature, heat transfer, and pressure range.