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

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.

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

Energies ◽

10.3390/en12010128 ◽

2018 ◽

Vol 12 (1) ◽

pp. 128 ◽

Cited By ~ 5

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.

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

Journal of Solar Energy Engineering ◽

10.1115/1.3266115 ◽

1980 ◽

Vol 102 (1) ◽

pp. 16-21 ◽

Cited By ~ 43

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.

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Impact of the Expansion Ratio on the Unsteady Aerodynamics and Performance of a HP Axial Turbine

Volume 2B: Turbomachinery ◽

10.1115/gt2016-56650 ◽

2016 ◽

Author(s):

P. Gaetani ◽

G. Persico ◽

A. Spinelli ◽

A. Mora

Keyword(s):

Flow Field ◽

Incidence Angle ◽

Flow Direction ◽

Axial Flow ◽

Unsteady Aerodynamics ◽

Fast Response ◽

Expansion Ratio ◽

Operating Conditions ◽

Inlet Temperature ◽

And Performance

In the frame of the European research project RECORD, the flow field within a HP axial-flow turbine model was investigated experimentally for several operating conditions. A number of studies on stator-rotor interaction in HP turbines for subsonic as well as transonic/supersonic conditions were proposed in the last decades, but none of them compared different conditions for the same geometry. In this paper, the transonic condition is investigated and compared to three subsonic ones, in the frame of an entirely new experimental campaign. The research was performed at the Laboratorio di Fluidodinamica delle Macchine of the Politecnico di Milano (Italy), where a cold-flow, closed-loop test rig is available for detailed studies on turbines and compressors. The boundary conditions resulted in keeping constant both the turbine inlet temperature and the stage outlet absolute flow direction; so far, while the expansion ratio was varied, the rotational speed was also modified accordingly. The analysis was performed by means of a conventional five hole probe in the stator – rotor axial gap and by a fast response aerodynamic probe downstream of the rotor. The local time-averaged and phase-resolved flow field was then derived and used to analyze the stage aerodynamics and performance. Results show that the stage expansion ratio has a dramatic impact on both the rotor aerodynamics and stage performance. In particular, Mach number effects are recognized in the stator cascade that passes from transonic to low subsonic conditions. On the rotor cascade the reduction of expansion ratio reduces significantly the Mach and Reynolds numbers and increases the incidence angle as well; the rotor loss mechanics as well as the vane-rotor interaction are greatly amplified. Correspondingly a significant variation of stage overall efficiency is recorded.

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Modeling, Simulation, and Performance Evaluation Analysis of a Parabolic Trough Solar Collector Power Plant Coupled to an Organic Rankine Cycle Engine in North Eastern Greece Using trnsys

Journal of Solar Energy Engineering ◽

10.1115/1.4043658 ◽

2019 ◽

Vol 141 (6) ◽

Cited By ~ 1

Author(s):

Pantelis N. Botsaris ◽

Alexandros G. Pechtelidis ◽

Konstantinos A. Lymperopoulos

Keyword(s):

Power Plant ◽

Simulation Model ◽

Small Deviation ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Operating Conditions ◽

Parabolic Trough ◽

Hybrid Power ◽

Hybrid Power Plant ◽

And Performance

The present work is focused on the development of a simulation model for an existing cogeneration power plant, which utilizes a solar thermal field with parabolic trough solar collectors coupled to an Organic Rankine Cycle engine. The power plant is modeled in the trnsys v.17 software package and its performance has been validated with real operating conditions. The simulated system (concentrated solar power (CSP) field and ORC engine) is the main part of a hybrid power plant located near “Ziloti” village of the Municipality of Xanthi, in northeastern Greece. The construction of the hybrid power plant was funded by the Strategic Co-Funded Project of the European Territorial Cooperation Program Greece–Bulgaria 2007–2013 with the acronym ENERGEIA. The power plant simulated in this paper includes a 234 kWth solar parabolic trough collector (PTC) field, a 5 m3 thermal energy storage tank, and a 5 kWe ORC engine for the production of thermal and electrical energies. The results of the simulations present small deviation in contrast to the real operating data of the CSP power plant coupled with the ORC engine, therefore the simulation model is considered as reliable.

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Optical-Mechanical Analysis of Parabolic Trough Solar Concentrators to Support Commercial Development

ASME 2013 7th International Conference on Energy Sustainability ◽

10.1115/es2013-18159 ◽

2013 ◽

Cited By ~ 1

Author(s):

Kenneth Biggio ◽

Rachel Backes ◽

Jennifer Crawford

Keyword(s):

Design Process ◽

Performance Metrics ◽

Mechanical Analysis ◽

Optical Performance ◽

Parabolic Trough ◽

Commercial Development ◽

Spatially Resolved ◽

Cost Of Energy ◽

And Performance ◽

The Cost

The thermal performance of parabolic trough concentrating solar collectors depends on both the structural and optical characteristics of the design. In order to reduce the cost of energy, advanced concentrating structures must significantly reduce the cost of collectors while maintaining good optical performance. This paper discusses a Finite Element Ray Tracer (FERT) that has been developed specifically to support the commercial design process. This is achieved by tying the whole of the support structure directly to its optical effects. Consequently, the optical performance metrics go beyond the typical reflector slope error RMS or average intercept factor to present the designer with spatially resolved analysis of localized performance. By incorporating this analytical method into the structural design process, collector cost and performance can be balanced efficiently and rapidly, allowing for an accelerated design period. At times, this insight has driven better, albeit unexpected, design decisions. The paper presents an overview of the development process that Abengoa R&D uses to take advantage of its analytical optical analysis capability throughout all phases of a project, as well as a review of its implementation. A selection of case studies is also presented to illustrate how FERT enables the designer to identify local areas of concern, diagnose the cause, and quickly develop possible redesign strategies. Finally, the significance of various parameters within the ray tracer are discussed.

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Heavy Duty Gas Turbine Simulation: Global Performances Estimation and Secondary Air System Modifications

Volume 4: Cycle Innovations; Electric Power; Industrial and Cogeneration; Manufacturing Materials and Metallurgy ◽

10.1115/gt2006-90905 ◽

2006 ◽

Cited By ~ 2

Author(s):

Carlo Carcasci ◽

Bruno Facchini ◽

Stefano Gori ◽

Luca Bozzi ◽

Stefano Traverso

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Cooling System ◽

Energy System ◽

Operating Conditions ◽

Coupled Analysis ◽

Ambient Conditions ◽

Air System ◽

Secondary Air ◽

And Performance

This paper reviews a modular-structured program ESMS (Energy System Modular Simulation) for the simulation of air-cooled gas turbines cycles, including the calculation of the secondary air system. The program has been tested for the Ansaldo Energia gas turbine V94.3A, which is one of the more advanced models in the family Vx4.3A with a rated power of 270 MW. V94.3A cooling system has been modeled with SASAC (Secondary Air System Ansaldo Code), the Ansaldo code used to predict the structure of the flow through the internal air system. The objective of the work was to investigate the tuning of the analytical program on the basis of the data from design and performance codes in use at Ansaldo Energy Gas Turbine Department. The results, both at base load over different ambient conditions and in critical off-design operating points (full-speed-no-load and minimum-load), have been compared with APC (Ansaldo Performance Code) and confirmed by field data. The coupled analysis of cycle and cooling network shows interesting evaluations for components life estimation and reliability during off-design operating conditions.

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Thermal performance of a solar oven with augmented sunlight concentration

Journal of Energy in Southern Africa ◽

10.17159/2413-3051/2007/v18i2a3368 ◽

2007 ◽

Vol 18 (2) ◽

pp. 4-10 ◽

Cited By ~ 1

Author(s):

M.J. Brooks

Keyword(s):

Thermal Performance ◽

Operating Temperature ◽

Incidence Angle ◽

Normal Incidence ◽

Operating Conditions ◽

Partial Shading ◽

Test Range ◽

Efficiency Performance ◽

And Performance ◽

Sky Conditions

This paper describes the thermal performance of a novel solar oven that incorporates a compact reflec-tive lens, or ring array, to augment sunlight concen-tration. Performance is reported in terms of the pos-itive effect of the ring array versus a non-concen-trating lid, maximum operating temperature, ther-mal efficiency, performance under partly cloudy skies, and the effects of incidence angle and track-ing. Use of the ring array lens improved thermal efficiency by 4% in the test range up to 100°C, while boosting the maximum operating temperature from 138°C to 196°C. Comparative tests conducted under clear sky conditions against two other com-mercial types showed that when tracked in the azimuth plane at near-normal incidence angles, the new design generated maximum cooking power of 300 W and boiled water at a rate 13% faster than the next best commercial oven tested. Augmented sunlight concentration sensitised the new design to higher angles of incidence and performance was negatively affected in the non-tracked state. Under non-ideal operating conditions, including partial shading by cloud, the oven outperformed both commercial units.

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A detailed parameter study on the comprehensive characteristics and performance of a parabolic trough solar collector system

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2013.11.011 ◽

2014 ◽

Vol 63 (1) ◽

pp. 278-289 ◽

Cited By ~ 52

Author(s):

Ze-Dong Cheng ◽

Ya-Ling He ◽

Kun Wang ◽

Bao-Cun Du ◽

F.Q. Cui

Keyword(s):

Solar Collector ◽

Parameter Study ◽

Parabolic Trough ◽

Collector System ◽

And Performance ◽

Parabolic Trough Solar Collector

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Study on the Optical Properties of Triangular Cavity Absorber for Parabolic Trough Solar Concentrator

International Journal of Photoenergy ◽

10.1155/2015/895946 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 9

Author(s):

Fei Chen ◽

Ming Li ◽

Reda Hassanien Emam Hassanien ◽

Xi Luo ◽

Yongrui Hong ◽

...

Keyword(s):

Optical Properties ◽

Orthogonal Experiment ◽

Optical Design ◽

Width Ratio ◽

Solar Concentrator ◽

Parabolic Trough ◽

Optical Efficiency ◽

Offset Distance ◽

Aperture Width ◽

Design Software

A theoretical analytical method for optical properties of cavity absorber was proposed in this paper and the optical design software TracePro was used to analyze the optical properties of triangular cavity absorber. It was found that the optimal optical properties could be achieved with appropriate aperture width, depth-to-width ratio, and offset distance from focus of triangular cavity absorber. Based on the results of orthogonal experiment, the optimized triangular cavity absorber was designed. Results showed that the standard deviation of irradiance and optical efficiency of optimized designed cavity absorber were 30528 W/m2and 89.23%, respectively. Therefore, this study could offer some valuable references for designing the parabolic trough solar concentrator in the future.

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