scholarly journals Incidence Angle Modifier and Average Optical Efficiency of Parabolic Trough Collectors

1979 ◽  
Author(s):  
H. Gaul ◽  
A. Rabl
Keyword(s):  
Incidence Angle ◽  
Parabolic Trough ◽  
Optical Efficiency

scholarly journals Investigation on the Optical Design and Performance of a Single-Axis-Tracking Solar Parabolic trough Collector with a Secondary Reflector

2021 ◽  
Vol 13 (17) ◽  
pp. 9918
Author(s):  
Chinnasamy Subramaniyan ◽  
Jothirathinam Subramani ◽  
Balasubramanian Kalidasan ◽  
Natarajan Anbuselvan ◽  
Thangaraj Yuvaraj ◽  
...  
Keyword(s):  
Incidence Angle ◽  
Optical Design ◽  
Operating Conditions ◽  
Optical Performance ◽  
Ambient Conditions ◽  
Parabolic Trough ◽  
Tracking Errors ◽  
Optical Efficiency ◽  
Collector System ◽  
And Performance

The design of solar concentrating collectors for the effective utilization of solar energy is a challenging condition due to tracking errors leading to different divergences of the solar incidence angle. To enhance the optical performance of solar parabolic trough collectors (SPTC) under a diverged solar incidence angle, an additional compound parabolic concentrator (CPC) is introduced as a secondary reflector. SPTC with CPC is designed and modeled for a single axis-tracking concentrating collector based on the local ambient conditions. In this work, the optical performance of the novel SPTC system with and without a secondary reflector is investigated using MATLAB and TRACEPRO software simulations for various tracking errors. The significance parameters such as the solar incidence angle, aperture length, receiver tube diameter, rim angle, concentration ratio, solar radiation, and absorbed flux are analyzed. The simulation results show that the rate of the absorbed flux on the receiver tube is significantly improved by providing the secondary reflector, which enhances the optical efficiency of the collector. It is found that the optical efficiency of the SPTC with a secondary reflector is 20% higher than the conventional collector system for a solar incidence angle of 2°. This work can effectively direct the choice of optimal secondary reflectors for SPTC under different design and operating conditions.

scholarly journals Performance Simulation Comparison for Parabolic Trough Solar Collectors in China

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinping Wang ◽  
Jun Wang ◽  
Xiaolong Bi ◽  
Xiang Wang
Keyword(s):  
Mathematical Model ◽  
Solar Collector ◽  
Incidence Angle ◽  
Accurate Estimation ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Optical Efficiency ◽  
Different Seasons ◽  
Shadowing Effect ◽  
Parabolic Trough Solar Collector

Parabolic trough systems are the most used concentrated solar power technology. The operating performance and optical efficiency of the parabolic trough solar collectors (PTCs) are different in different regions and different seasons. To determine the optimum design and operation of the parabolic trough solar collector throughout the year, an accurate estimation of the daily performance is needed. In this study, a mathematical model for the optical efficiency of the parabolic trough solar collector was established and three typical regions of solar thermal utilization in China were selected. The performance characteristics of cosine effect, shadowing effect, end loss effect, and optical efficiency were calculated and simulated during a whole year in these three areas by using the mathematical model. The simulation results show that the optical efficiency of PTCs changes from 0.4 to 0.8 in a whole year. The highest optical efficiency of PTCs is in June and the lowest is in December. The optical efficiency of PTCs is mainly influenced by the solar incidence angle. The model is validated by comparing the test results in parabolic trough power plant, with relative error range of 1% to about 5%.

scholarly journals Incidence-Angle Modifier and Average Optical Efficiency of Parabolic Trough Collectors

1980 ◽  
Vol 102 (1) ◽  
pp. 16-21 ◽  
Author(s):  
H. Gaul ◽  
A. Rabl
Keyword(s):  
Incidence Angle ◽  
Open Water ◽  
Operating Conditions ◽  
Parabolic Trough ◽  
Optical Efficiency ◽  
Arbitrary Length ◽  
Polynomial Fit ◽  
Test Loop ◽  
Single Number ◽  
Solar Energy Research Institute

The incidence-angle modifier for parabolic troughs is investigated in order to clarify the connection between collector tests and prediction of long-term energy delivery by collector arrays. The optical efficiency of a parabolic trough collector decreases with incidence angle for several reasons: the decreased transmission of the glazing and the absorption of the absorber; the increased width of the solar image on the receiver; and the spillover of the radiation from troughs of finite length. In order to be able to apply test results from a short collector module to collector arrays of arbitrary length, it is necessary to separate analytically the end loss from the first two effects. This analysis is applied to several collectors that have been tested at Sandia Laboratories and at the Solar Energy Research Institute (SERI). The measurements of the incidence-angle modifier at SERI were, carried out at low temperature with an open water test loop for improved accuracy. The results are presented in two forms: as a polynomial fit to the data; and as a single number, the all-day average optical efficiency for typical operating conditions.

A High-Precision Control System Used for Optical Efficiency Measurements of Parabolic Trough Collectors at NREL

2012 ◽  
Author(s):  
Guangdong Zhu ◽  
Judy Netter ◽  
Allison Gray
Keyword(s):  
Control System ◽  
Tracking Control ◽  
Incidence Angle ◽  
Control Program ◽  
Tracking Accuracy ◽  
Parabolic Trough ◽  
Optical Efficiency ◽  
Test Loop ◽  
Challenges And Opportunities ◽  
Monitoring And Diagnostics

The testing facility called the Outdoor Collector Test Loop (OCTL), which is located at the Solar Industrial Mesa Top Area (SIMTA) of National Renewable Energy Lab (NREL), measures the optical efficiency of parabolic trough collectors. It uses a dual-axis, large-payload solar tracker to hold a parabolic trough collector module and track the sun. Due to the growing need for measurement accuracy and efficiency, a new tracking control system for the tracker has been acquired and successfully commissioned as of February 2012. As part of the customization needed to address the unique testing requirements at the OCTL, new tracking modes have been designed and embedded into the new controller. In particular, the incidence angle modifier (IAM) and fixed-azimuth modes allows the OCTL to readily measure the IAM values for a trough collector, significantly improving the speed and efficiency of IAM data collection compared to the previous controller (with test times of days versus weeks). The Siemens S7 1200 PLC integrates various hardware components (such as the hydraulic pump, encoders, sun sensor and wind sensor) through corresponding communication channels, and a Simatic HMI panel provides a powerful user-friendly interface for operation, monitoring, and diagnostics. In addition, NREL integrated the Siemens tracking control program with the existing LabVIEW program that serves as a user interface of the thermal fluid loop, and calibrated the tracking platform as a whole to characterize its tracking accuracy. At last, the challenges and opportunities for the control system in the area of concentrating solar power (CSP) are briefly discussed.

Comparison of Two Linear Collectors in Solar Thermal Plants: Parabolic Trough vs Fresnel

2011 ◽  
Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Research Activity ◽  
Optical Efficiency ◽  
Synthetic Oil ◽  
Yearly Average

Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on synthetic oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex®, with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and synthetic oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.

Study on Optical Efficiency Characteristics of Receivers in a Solar Parabolic Trough Concentrator

2016 ◽  
Vol 36 (1) ◽  
pp. 0122002
Author(s):  
冯志康 Feng Zhikang ◽  
李明 Li Ming ◽  
王云峰 Wang Yunfeng ◽  
陈飞 Chen Fei ◽  
冀孟恩 Ji Meng′en ◽  
...  
Keyword(s):  
Parabolic Trough ◽  
Optical Efficiency

scholarly journals Effect of the Orientation Schemes of the Energy Collection Element on the Optical Performance of a Parabolic Trough Concentrating Collector

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 128 ◽  
Author(s):  
Majedul Islam ◽  
Prasad Yarlagadda ◽  
Azharul Karim
Keyword(s):  
Monte Carlo ◽  
State Of The Art ◽  
Tracking Error ◽  
Surface Group ◽  
Energy Performance ◽  
Optical Performance ◽  
Extended Version ◽  
Parabolic Trough ◽  
Tracking Errors ◽  
Optical Efficiency

While the circular shape is currently the proven optimum design of the energy collection element (ECE) of a parabolic trough collector, that is yet to be confirmed for parabolic trough concentrating collectors (PTCCs) like trough concentrating photovoltaic collectors and hybrid photovoltaic/thermal collectors. Orientation scheme of the ECE is expected to have significant effect on the optical performance including the irradiance distribution around the ECE and the optical efficiency, and therefore, on the overall energy performance of the PTCC. However, little progress addressing this issue has been reported in the literature. In this study, a thorough investigation has been conducted to determine the effect of the orientation schemes of ECE on the optical performance of a PTCC applying a state-of-the-art Monte Carlo ray tracing (MCRT) technique. The orientation schemes considered are a flat rectangular target and a hollow circular, semi-circular, triangular, inverted triangular, rectangular and rectangle on semi-circle (RSc). The effect of ECE defocus, Sun tracking error and trough rim angle on the optical performance is also investigated. The MCRT study reveals that the ECE orientation schemes with a curved surface at the trough end showed much higher optical efficiency than those with a linear surface under ideal conditions. ECEs among the linear surface group, the inverted triangular orientation exhibited the highest optical efficiency, whereas the flat and triangular ones exhibited the lowest optical efficiency, and the rectangular one was in between them. In the event of defocus and tracking errors, a significant portion of the concentrated light was observed to be intercepted by the surfaces of the rectangular and RSc ECEs that are perpendicular to the trough aperture. This is an extended version of a published work by the current authors, which will help to design an optically efficient ECE for a parabolic trough concentrating collector.

Parametric Trough Solar Collector With Commercial Evacuated Receiver: Performance Comparison at Plant Level

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Juan Pablo Núnez Bootello ◽  
Markus Schramm ◽  
Manuel Silva Pérez ◽  
Manuel Doblaré Castellano
Keyword(s):  
Solar Collector ◽  
Power Plants ◽  
Incidence Angle ◽  
Performance Comparison ◽  
Fresnel Reflection ◽  
Optical Efficiency ◽  
Commercial Plant ◽  
Secondary Mirror ◽  
Plant Level ◽  
Solar Field

A new anidolic parametric trough solar collector (PmTC) having 8.12 m net width aperture has been recently proposed for a commercial evacuated receiver tube with an absorber diameter of 70 mm. Since the collector was designed ignoring transmission, absorption, and reflection optical losses, calculations of the optical efficiency and the incidence angle modifier (IAM) by means of Monte Carlo spectral raytracing simulations using real slope errors distributions and taking into account Fresnel reflection losses were done. Comparison with an Eurotrough parabolic trough collector (PTC) shows an optical penalization of 5.1% due to the reflectivity and additional soiling of the secondary mirror, to an increase in the end losses and to the Fresnel reflection losses. The National Renewable Energy Laboratory (NREL) system advisor model (SAM) was used to perform annual simulations of two commercial 50 MWe oil power plants without thermal energy storage located in Seville. A PTC solar field consisting of 90 loops, each one having four Eurotrough solar collector assemblies (SCA) with 150 m length was first modeled resulting in a gross production of 386 kWh/(m2 yr). A PmTC solar field with the same module length and similar SCA net aperture area was also simulated. A final configuration of 94 loops and four SCAs with 100 m length per loop yields a gross production of 379 kWh/(m2 yr) showing no improvement compared to the reference PTC plant. The present study allows to advance in the understanding of the potential of the anidolic optic to produce optical geometries able to effectively improve the PTC technology in the short-term projecting results at a commercial plant level.

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