The Experts below are selected from a list of 6354 Experts worldwide ranked by ideXlab platform
Zhifeng Wang - One of the best experts on this subject based on the ideXlab platform.
-
enhanced heat transfer in a Parabolic Trough solar receiver by inserting rods and using molten salt as heat transfer fluid
Applied Energy, 2018Co-Authors: Mingzhi Zhao, Zhifeng Wang, Chun Chang, Adriano Sciacovelli, Jie Deng, Yulong DingAbstract:Abstract With the aim to enhance the reliability and overall heat transfer performance of a Parabolic Trough receiver, concentric rod and eccentric rod are introduced as turbulators, and the flow and convective heat transfer characteristics of molten salt in a Parabolic Trough receiver are analyzed. A three-dimensional model was developed and has been validated with experimental results and empirical equations. Highly non-uniform heat flux was provided by a novel Parabolic Trough collector. The result shows that both concentric rod insert and eccentric rod insert can enhance the heat transfer performance effectively. For a Parabolic Trough receiver with a concentric rod insert, with the increasing of dimensionless diameter B, the normalized Nusselt number is about 1.10 to 7.42 times over a plain Parabolic Trough receiver. The performance evaluation criteria can't reasonably evaluate the effect of B growth on the comprehensive heat transfer performance. By introducing integrated performance factor, it can give a reasonable solution, and it shows that the integrated performance factor has a significance decreases with the increase of Reynolds number when B is larger than 0.8. With B increasing, the integrated performance factor of Parabolic Trough receiver with concentric rod insert decreasing under a certain Reynolds number. For an eccentric rod insert, the performance evaluation criteria and the integrated performance factor decrease with the increasing of Reynolds number under a certain dimensionless eccentricity H. The performance evaluation criteria decreases from about 1.84 to 1.68 times over a plain Parabolic Trough receiver when H is 0.8. Moreover, the temperature distribution can be uniformed and the maximum temperature on the absorber tube also can be remarkably reduced with the increasing of B and H under a certain Reynolds number, which helps to reduce the thermal deflection and increase the reliability for a Parabolic Trough receiver.
-
influences of installation and tracking errors on the optical performance of a solar Parabolic Trough collector
Renewable Energy, 2016Co-Authors: Dongming Zhao, Ershu Xu, Zhifeng Wang, Qiang Yu, Li XuAbstract:The Parabolic Trough collector is an important component of Parabolic Trough solar thermal power generation systems. Coordinate transformations and the Monte Carlo Ray Trace (MCRT) method were combined to simulate the circumferential flux distribution on absorber tubes. The simulation model includes the optics cone with non-parallel rays, geometric concentration ratios (GCs), the glass tube transmissivity, the absorber tube absorptance and the collector surface reflectivity. The mode is used to analyze the effects of absorber tube installation errors and reflector tracking errors. The results are compared with reference data to verify the model accuracy. Influences of installation and tracking errors on the flux distribution are analyzed for different errors, incident angles and GCs. For a GC of 20 and 90° rim angle, X direction installation errors are −0.2%∼0.2%, Y direction installation errors are −1.0%–0.5%, and the tracking error should be less than 4 mrad. As the incident angle increases, the errors become larger, but the errors become smaller as concentration ratios are increased. The results provide foundations for heat transfer analysis of the absorber tube, for Parabolic Trough plant to ensure the safe intensity, and for economic analysis of the installation process and control system.
-
the badaling 1mw Parabolic Trough solar thermal power pilot plant
Energy Procedia, 2015Co-Authors: Ershu Xu, Dongming Zhao, Hui Xu, Shidong Li, Zhiqiang Zhang, Zhiyong Wang, Zhifeng WangAbstract:Abstract In order to master the design, integration and operation technology of Parabolic Trough solar thermal power (PTSTP) plant and lay a solid foundation for the future development of large-scale PTSTP station, China sets up a research project “National High Technology Research and Development of China 863 Program (2012AA050603)”during the National “12th Five-Year Plan”, which aims to establish a 1MW Parabolic Trough Solar Thermal Power pilot plant in Badaling Yanqing. In this paper, it introduces the collector field arrangement, the composition and the function of 1MW pilot plant in detail.
-
structural reliability analysis of Parabolic Trough receivers
Applied Energy, 2014Co-Authors: Zhiyong Wu, Guofeng Yuan, Jiajia Shao, Yunting Zhang, Zhifeng WangAbstract:Parabolic Trough receivers typically account for 30% of the cost of a solar field. Furthermore, experiences show the cost of operation and maintenance of Parabolic Trough receivers over the lifetime of the system can be quite high as regular maintenance is required. Therefore, the receiver’s cost and structural reliability is crucial to guarantee the Parabolic Trough plants work steadily, safely and above all, economically. The structure of a Parabolic Trough receiver is principally a stainless steel inner tube surrounded by a glass outer tube. Because the stainless steel tube has 4m long and is easy to get bent, the glass outer tube is quite fragile and therefore prone to break. Experiences in field operations show the bending of stainless steel tube is the main reason of Parabolic Trough receiver’s structural failure. This study mainly investigates why and how the stainless steel tubes get bent. In this paper, an indoor experiment, numerical simulations (CFD and FEA) and field measurements are conducted to jointly investigate the causes of stainless steel tube’s bending. An indoor experiment is conducted on a heat loss test-rig, and the deflection of the stainless steel tube under different isothermal conditions is studied. Numerical simulations are used to investigate the detailed temperature distribution, and its corresponding structural deformation of the stainless steel tube of Parabolic Trough receivers. The simulations adapt a MCRT code, FLUENT software and ANSYS workbench. Finally, field measurements are conducted on a 36m long Parabolic Trough collector to investigate the stainless steel tube bending under different working conditions. This study shows that improper installation and operational practices of Parabolic Trough receivers are the main causes for the structural failure of the Parabolic Trough’s receiver. This study is of great importance to guide the installation and operation of Parabolic Trough receivers.
-
three dimensional numerical study of heat transfer characteristics of Parabolic Trough receiver
Applied Energy, 2014Co-Authors: Guofeng Yuan, Dongqiang Lei, Zhifeng WangAbstract:Parabolic Trough receivers are the key component of Parabolic Trough solar plants, and they typically account for 30% of the cost of the construction of a solar field. The receiver’s reliability is still a major item which affects the plant’s cost. The temperature distribution of the Parabolic Trough receivers is required to identify the causation of Parabolic Trough receiver’s failure, and is the prerequisite to design and optimize the Parabolic Trough receiver’s structure. In this study, the detailed temperature distribution of a Parabolic Trough receiver is successfully simulated by combining a MCRT code and FLUENT software. The heat transfer fluid flow, conduction and radiation heat transfers are jointly considered. Temperature-dependent properties of the heat transfer fluid, the wavelength-dependent optical properties of the receiver surfaces and the glass envelope’s absorption of the solar radiation energy are also taken into account. Comparison with indoor experimental results show the average difference is within 6%. In addition, the transient behaviors of Parabolic Trough receiver under direct concentrated solar irradiance are investigated. The information from this study is of great importance to the design and the optimization of the structure of Parabolic Trough receiver, as well as to identify the causation of Parabolic Trough receiver’s failure.
Ayad K Khlief - One of the best experts on this subject based on the ideXlab platform.
-
an integrated program of a stand alone Parabolic Trough solar thermal power plant code description and test
Case Studies in Thermal Engineering, 2018Co-Authors: Sanan T Mohammad, Hussain H Alkayiem, Morteza Khalaji Assadi, Osama. Sabir, Ayad K KhliefAbstract:Abstract 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, U L , aperture effective direct normal irradiance, I , heat gain, Q gain , and the thermal efficiency of stand-alone Parabolic Trough solar thermal power plant in commerce, η p . 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.
-
performance and simulation of a stand alone Parabolic Trough solar thermal power plant
IOP Conference Series: Earth and Environmental Science, 2018Co-Authors: Sanan T Mohammad, Hussain H Alkayiem, Morteza Khalaji Assadi, S I Gilani, Ayad K KhliefAbstract: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
Elsevier, 2018Co-Authors: Sanan T Mohammad, Morteza Khalaji Assadi, Hussain H. Al-kayiem, Osama. Sabir, Ayad K KhliefAbstract: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. Keywords: Direct normal radiation, Direct steam generation, Parabolic Trough solar thermal power plan
Christos Tzivanidis - One of the best experts on this subject based on the ideXlab platform.
-
alternative designs of Parabolic Trough solar collectors
Progress in Energy and Combustion Science, 2019Co-Authors: Evangelos Bellos, Christos TzivanidisAbstract:Abstract Parabolic Trough collector (PTC) is the most established solar concentrating technology worldwide. The conventional Parabolic Trough collectors are used in various applications of medium and high-temperature levels. However, there are numerous studies which investigate alternative designs. The reasons for examining different PTC configurations regard the thermal efficiency increase, the reduction of the manufacturing cost and the development of more compact designs. The objective of this review paper is to summarize the existing alternative designs of PTC and to suggest the future trends in this area. Optical and thermal modifications are examined, as well as the use of concentrating thermal photovoltaic collectors. The optical modifications include designs with secondary concentrators, stationary concentrators and strategies for achieving uniform heat flux. The thermal modifications regard the use of nanofluids, turbulators and the use of thermally modified receivers with insulation, double-coating and radiation shields. The concentrating thermal photovoltaics are systems with flat or triangular receivers which can operate in low or in medium temperature levels with the proper alternative designs. It has been found that there are many promising choices for designing PTC with higher thermal performance and lower cost. The conclusions of this work can be used as guidelines for future trends in linear Parabolic concentrating technologies.
-
multiple cylindrical inserts for Parabolic Trough solar collector
Applied Thermal Engineering, 2018Co-Authors: Evangelos Bellos, Ilias Daniil, Christos TzivanidisAbstract:Abstract The use of insert flow is a promising technique for increasing the performance of Parabolic Trough solar collectors. The objective of this work is to investigate the use of multiple cylindrical longitudinal inserts in the Parabolic Trough solar collector LS-2 module. Totally 15 cases are investigated with a computational dynamic model developed in SolidWorks Flow Simulation. More specifically, the reference empty tube, one case with a single insert, eight cases with two inserts flow, three cases with three insert flow and two cases with four insert flow. It is found that the use of more inserts leads to higher thermal, exergy and overall efficiency performance of the collector. Moreover, it is found that the exact location of the inserts plays a significant role in the results. The pumping work is found to be generally low in all the cases, the fact that proves that the increase in the pressure drop is not so important in the total system performance. The global maximum efficiency is found for the case with the four inserts and in this case, the thermal efficiency is enhanced 0.656%, the thermal losses are reduced about 5.63% and the heat transfer coefficient is increased 26.88%. The results of this work can be used for the proper design of multiple inserts design in solar systems.
-
Analytical Expression of Parabolic Trough Solar Collector Performance
Designs, 2018Co-Authors: Evangelos Bellos, Christos TzivanidisAbstract:The Parabolic Trough collector is one of the most developed solar concentrating technologies for medium and high temperatures (up to 800 K). This solar technology is applied in many applications and so its investigation is common. The objective of this study is to develop analytical expressions for the determination of the thermal performance of Parabolic Trough collectors. The non-linear equations of the energy balances in the Parabolic Trough collector device are simplified using suitable assumptions. The final equation set includes all the possible parameters which influence the system performance and it can be solved directly without computational cost. This model is validated using experimental literature results. Moreover, the developed model is tested using another model written in Engineering Equation Solver under different operating conditions. The impact of the inlet fluid temperature, flow rate, ambient temperature, solar beam irradiation, and the heat transfer coefficient between cover and ambient are the investigated parameters for testing the model accuracy. According to the final results, the thermal efficiency can be found with high accuracy; the deviations are found to be up to 0.2% in the majority of the examined cases. Thus, the results of this work can be used for the quick and accurate thermal analysis of Parabolic Trough collector. Moreover, the analytical expressions give the possibility for optimizing solar thermal systems driven by Parabolic Trough collectors with lower computational cost.
-
a detailed exergetic analysis of Parabolic Trough collectors
Energy Conversion and Management, 2017Co-Authors: Evangelos Bellos, Christos TzivanidisAbstract:Abstract The objective of this study is to present a detailed exergetic analysis of the commercial Parabolic Trough collector LS-2. A complete thermal model is developed in EES (Engineering Equation Solver) and it is validated with literature results. The solar collector is examined for operation with Therminol VP1 and air in order to examine the most representative liquid and gas working fluids. In the exergetic analysis, detailed presentation of the exergetic losses and the exergy destruction is given for various operation cases. More specifically, different combinations of flow rates and inlet temperature levels are tested for both working fluids and the results indicate the reasons for the exergetic reduction in every case. According to the final results, the global maximum exergetic efficiency for operation with air is 25.62% for an inlet temperature of 500 K and flow rate of 10,000 l/min, while for Therminol VP1 is 31.67% for 500 K and 100 l/min. Moreover, it is proved that the exergy destruction is more intense in the thermal oil case, while the exergetic losses are more important in the air case. The final results and conclusions clearly present the exergetic analysis of Parabolic Trough collector for a great range of operating conditions.
-
thermal and optical efficiency investigation of a Parabolic Trough collector
Case Studies in Thermal Engineering, 2015Co-Authors: Christos Tzivanidis, Evangelos Bellos, Dimitrios M Korres, K A Antonopoulos, G MitsopoulosAbstract:Abstract Solar energy utilization is a promising Renewable Energy source for covering a variety of energy needs of our society. This study presents the most well-known solar concentrating system, the Parabolic Trough collector, which is operating efficiently in high temperatures. The simulation tool of this analysis is the commercial software Solidworks which simulates complicated problems with an easy way using the finite elements method. A small Parabolic Trough collector model is designed and simulated for different operating conditions. The goal of this study is to predict the efficiency of this model and to analyze the heat transfer phenomena that take place. The efficiency curve is compared to a one dimensional numerical model in order to make a simple validation. Moreover, the temperature distribution in the absorber and inside the tube is presented while the heat flux distribution in the outer surface of the absorber is given. The heat convection coefficient inside the tube is calculated and compared with the theoretical one according to the literature. Also the angle efficiency modifier is calculated in order to predict the thermal and optical efficiency for different operating conditions. The final results show that the PTC model performs efficiently and all the calculations are validated.
Sanan T Mohammad - One of the best experts on this subject based on the ideXlab platform.
-
an integrated program of a stand alone Parabolic Trough solar thermal power plant code description and test
Case Studies in Thermal Engineering, 2018Co-Authors: Sanan T Mohammad, Hussain H Alkayiem, Morteza Khalaji Assadi, Osama. Sabir, Ayad K KhliefAbstract:Abstract 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, U L , aperture effective direct normal irradiance, I , heat gain, Q gain , and the thermal efficiency of stand-alone Parabolic Trough solar thermal power plant in commerce, η p . 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.
-
performance and simulation of a stand alone Parabolic Trough solar thermal power plant
IOP Conference Series: Earth and Environmental Science, 2018Co-Authors: Sanan T Mohammad, Hussain H Alkayiem, Morteza Khalaji Assadi, S I Gilani, Ayad K KhliefAbstract: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
Elsevier, 2018Co-Authors: Sanan T Mohammad, Morteza Khalaji Assadi, Hussain H. Al-kayiem, Osama. Sabir, Ayad K KhliefAbstract: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. Keywords: Direct normal radiation, Direct steam generation, Parabolic Trough solar thermal power plan
Wolf-dieter Steinmann - One of the best experts on this subject based on the ideXlab platform.
-
Solid media thermal storage for Parabolic Trough power plants
Solar Energy, 2006Co-Authors: Doerte Laing, Wolf-dieter Steinmann, Rainer Tamme, Christoph RichterAbstract:For Parabolic Trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option regarding investment and maintenance costs. In the project WESPE that is described in this paper, solid media sensible heat storage materials have been researched. Two storage systems with a storage capacity of about 350kWh each and maximum temperatures of 390°C have been developed. The test storage units of WESPE are erected at the Plataforma Solar de Almeria in Spain. The thermal energy is provided by a Parabolic Trough loop with a maximum thermal power of 480kW. The first tests were performed at storage temperatures up to 325°C by March of 2004; testing will be continued during 2004 to achieve the nominal operation conditions of 390°C and to gain experience for long term behaviour. These storage systems are composed of modules with two different storage materials to identify the characteristics of these materials. A tubular heat exchanger is integrated into the storage material. This heat exchanger demands a significant share of the investment costs. The selection of geometry parameters like tube diameter and number of tubes therefore play an important role in the optimisation. The design of the WESPE test module is based on results provided by a numerical tool for simulation of the transient performance of storage systems.
-
advanced thermal energy storage technology for Parabolic Trough
Journal of Solar Energy Engineering-transactions of The Asme, 2004Co-Authors: Rainer Tamme, Doerte Laing, Wolf-dieter SteinmannAbstract:The availability of storage capacity plays an important role for the economic success of solar thermal power plants. For today's Parabolic Trough power plants, sensible heat storage systems with operation temperatures between 300°C and 390°C can be used. A solid media sensible heat storage system is developed and will be tested in a Parabolic Trough test loop at PSA, Spain. A simulation tool for the analysis of the transient performance of solid media sensible heat storage systems has been implemented. The computed results show the influence of various parameters describing the storage system. While the effects of the storage material properties are limited, the selected geometry of the storage system is important. The evaluation of a storage system demands the analysis of the complete power plant and not only of the storage unit. Then the capacity of the system is defined by the electric work produced by the power plant, during a discharge process of the storage unit. The choice of the operation strategy for the storage system proves to be essential for the economic optimization.
-
advanced thermal energy storage technology for Parabolic Trough
Solar Energy, 2003Co-Authors: Rainer Tamme, Doerte Laing, Wolf-dieter SteinmannAbstract:The availability of storage capacity plays an important role for the economic success of solar thermal power plants. For today’s Parabolic Trough power plants, sensible heat storage systems with operation temperatures between 300°C and 390°C can be used. A solid media sensible heat storage system is developed and will be tested in a Parabolic Trough test loop at PSA, Spain. A simulation tool for the analysis of the transient performance of solid media sensible heat storage systems has been implemented. The computed results show the influence of various parameters describing the storage system. While the effects of the storage material properties are limited, the selected geometry of the storage system is important. The evaluation of a storage system demands the analysis of the complete power plant and not only of the storage unit. Then the capacity of the system is defined by the electric work produced by the power plant, during a discharge process of the storage unit. The choice of the operation strategy for the storage system proves to be essential for the economic optimization.Copyright © 2003 by ASME
