Research Papers

Comparison of Different Strategies for Heliostats Aiming Point in Cavity and External Tower Receivers

[+] Author and Article Information
Marco Binotti

Group of Energy Conversion Systems (GECOS),
Dipartimento di Energia,
Politecnico di Milano,
Via Lambruschini 4,
Milano 20156, Italy

Paolo De Giorgi

Group of Energy Conversion Systems (GECOS),
Dipartimento di Energia,
Politecnico di Milano,
Via Lambruschini 4,
Milano 20156, Italy;
Thermal Power Group (GMTS),
University of Seville,
Camino de los descubrimientos s/n,
Seville 41092, Spain

David Sanchez

Thermal Power Group (GMTS),
University of Seville,
Camino de los descubrimientos s/n,
Seville 41092, Spain

Giampaolo Manzolini

Group of Energy Conversion Systems (GECOS),
Dipartimento di Energia,
Politecnico di Milano,
Via Lambruschini 4,
Milano 20156, Italy
e-mail: giampaolo.manzolini@polimi.it

1Corresponding author.

Contributed by the Solar Energy Division of ASME for publication in the JOURNAL OF SOLAR ENERGY ENGINEERING: INCLUDING WIND ENERGY AND BUILDING ENERGY CONSERVATION. Manuscript received July 14, 2014; final manuscript received December 14, 2015; published online February 5, 2016. Assoc. Editor: Dr. Akiba Segal.

J. Sol. Energy Eng 138(2), 021008 (Feb 05, 2016) (11 pages) Paper No: SOL-14-1204; doi: 10.1115/1.4032450 History: Received July 14, 2014; Revised December 14, 2015

This paper investigates different strategies for the reduction of peak heat fluxes on the receiver of a solar tower plant through the variation of the heliostats aiming points. The analysis is performed for two different solar tower receivers and heliostat field layouts. The innovative aspect of the work is in the methodology proposed: the effect of different aiming points is evaluated at different sun positions, and the yearly optical efficiency is calculated to determine drawbacks in terms of energy production. The optical simulation of the solar plant is performed with delsol through a matlab suite to easily manage the input and output. Preliminary assessments showed that the most important displacement is the vertical one, and the variation of the aiming point is important for the rows that are closer to the tower. With the appropriate strategy, the peak heat flux can be reduced by about 40% with limited spillage increase compared to the reference case. This result is similar for the two investigated plants, and it is confirmed also at different sun positions. The yearly optical efficiency with the optimal aiming strategy is reduced by less than 0.5% points. Future analysis will assess potential cost reductions and thermal efficiency increase brought about by the proposed strategies.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.


REN21, 2013, Renewables 2013 Global Status Report, REN21 Secretariat, Paris.
IEA, 2011, Solar Energy Perspectives, IEA, Paris, France.
Wright, S. , Scott, D. , Haddow, J. , and Rosen, M. , 2000, “ The Upper Limit to Solar Energy Conversion,” 35th Intersociety Energy Conversion Engineering Conference and Exhibition (IECEC), Las Vegas, NV, July 24–28, pp. 384–392.
Alliance, C SP, 2012, “ The Economic and Reliability Benefits of CSP With Thermal Energy Storage: Recent Studies and Research Needs,” CSP Alliance Report 2012, http://www.csp-alliance.org/
Denholm, P. , and Hummon, M. , 2012, “ Simulating the Value of Concentrating Solar Power With Thermal Energy Storage in a Production Cost Model,” NREL, Golden, CO, Technical Report No. NREL/TP-6A20-56731.
Delaquil, P. , Kelly, B. , and Lessley, R. , 1991, “ Solar One Conversion Project,” Sol. Energy Mater., 24(1–4), pp. 151–161. [CrossRef]
Solucar, 2006, “ 10 MW Solar Thermal Power Plant for Southern Spain,” Project No. NNE5-1999-356.
Torresol Energy, 2014, “ Gemasolar,” http://www.torresolenergy.com/TORRESOL/gemasolar-plant/en
Ivanpah, 2014, “ Ivanpah Plant,” http://ivanpahsolar.com/
CSP World, 2014, “ CSP World Map,” http://www.csp-world.com/cspworldmap
Schell, S. , 2011, “ Design and Evaluation of Esolar's Heliostat Fields,” Sol. Energy, 85(4), pp. 614–619. [CrossRef]
Collado, F. J. , and Guallar, J. , 2013, “ A Review of Optimized Design Layouts for Solar Power Tower Plants With Campo Code,” Renewable Sustainable Energy Rev., 20, pp. 142–154. [CrossRef]
Collado, F. J. , 2009, “ Preliminary Design of Surrounding Heliostat Fields,” Renewable Energy, 34(5), pp. 1359–1363. [CrossRef]
Boerema, N. , Morrison, G. , Taylor, R. , and Rosengarten, G. , 2013, “ Science Direct High Temperature Solar Thermal Central-Receiver Billboard Design,” Sol. Energy, 97, pp. 356–368. [CrossRef]
Garcia, P. , Ferriere, A. , and Bezian, J. , 2008, “ Code for Solar Flux Calculation Dedicated to Central Receiver System Application: A Comparative Review,” Sol. Energy, 82(3), pp. 189–197. [CrossRef]
Rodríguez-Sánchez, M. R. , Soria-Verdugo, A. , Almendros-Ibáñez, J. A. , Acosta-Iborra, A. , and Santana, D. , 2014, “ Thermal Design Guidelines of Solar Power Towers,” Appl. Therm. Eng., 63(1), pp. 428–438. [CrossRef]
Sanchez, M. , and Romero, M. , 2006, “ Methodology for Generation of Heliostat Field Layout in Central Receiver Systems Based on Yearly Normalized Energy Surfaces,” Sol. Energy, 80(7), pp. 861–874. [CrossRef]
Landman, W. , and Gauché, P. , 2014, “ Influence of Canting Mechanism and Facet Profile on Heliostat Field Performance,” Energy Proc., 49, pp. 126–135. [CrossRef]
Buck, R. , and Teufel, E. , 2009, “ Comparison and Optimization of Heliostat Canting Methods,” ASME J. Sol. Energy Eng., 131(1), p. 011001. [CrossRef]
Besarati, S. M. , Yogi Goswami, D. , and Stefanakos, E. K. , 2014, “ Optimal Heliostat Aiming Strategy for Uniform Distribution of Heat Flux on the Receiver of a Solar Power Tower Plant,” Energy Convers. Manage., 84, pp. 234–243. [CrossRef]
Salomé, A. , Chhel, F. , Flamant, G. , Ferrière, A. , and Thiery, F. , 2013, “ Control of the Flux Distribution on a Solar Tower Receiver Using an Optimized Aiming Point Strategy: Application to THEMIS Solar Tower,” Sol. Energy, 94, pp. 352–366. [CrossRef]
Belhomme, B. , Pitz-Paal, R. , and Schwarzbözl, P. , 2013, “ Optimization of Heliostat Aim Point Selection for Central Receiver Systems Based on the Ant Colony Optimization Metaheuristic,” ASME J. Sol. Energy Eng., 136(1), p. 011005. [CrossRef]
Roccia, J. P. , Piaud, B. , Coustet, C. , Caliot, C. , Guillot, E. , Flamant, G. , and Delatorre, J. , 2012, “ SOLFAST: A Ray-Tracing Monte Carlo Software for Solar Concentrating Facilities,” J. Phys. Conf. Ser., 369(1), p. 012029.
NREL, 2012, “ SolTrace Optical Modeling Software,” http://www.nrel.gov/csp/soltrace/
Ho, C. , 2008, “ Software and Codes for Analysis of Concentrating Solar Power Technologies,” Sandia National Laboratories, Albuquerque, NM, Report No. SAND2008-8053.
Kistler, B. , 1986, “ User's Manual for DELSOL3: A Computer Code for Calculating the Optical Performance and Optimal System Design for Solar Thermal Central Receiver Plants,” Report No. SAND86-8018.
Sandia National Laboratories, 2014, “ Delsol,” http://energy.sandia.gov/?page_id=6530
Colzi, F. , Petrucci, S. , Manzolini, G. , Chacartegui, R. , and Campanari, S. , 2010, “ Modeling On/Off-Design Performance of Solar Tower Plants Using Saturated Steam,” ASME Paper No. ES2010-90399.
Osuna, R. , 2014, “ Solar Thermal Industry, Success Stories and Perspectives,” Last accessed Mar. 14, 2014, http://ec.europa.eu/research/energy/pdf/06_osuna_en.pdf
Rinaldi, F. , Binotti, M. , Giostri, A. , and Manzolini, G. , 2014, “ Comparison of Linear and Point Focus Collectors in Solar Power Plants,” Energy Proc., 49, pp. 1491–1500. [CrossRef]
“  Delsol Modelling Tool,” http://energy.sandia.gov/?page_id=6530


Grahic Jump Location
Fig. 1

Overall heat input to the receiver (left side) and peak flux (right side) for the PS10 plant at 12.00 hr on March 21 and 16.00 hr on June 21. Reference values are taken from Refs. [31] and [32], options 1 and 2 refer to the abovementioned solar field modeling options in delsol. Both options 1 and 2 assume one single aiming point at the center of the receiver.

Grahic Jump Location
Fig. 2

PS10 solar tower (left, http://www.nrel.gov/csp/solarpaces/project_detail.cfm/projectID=38) and Gemasolar (right, Copyright: Torresol Energy, Free Art License)

Grahic Jump Location
Fig. 3

Aerial views of the PS10 (top left) and of the Gemasolar (top right) heliostat fields taken from Map Data 2014 Google, Inst. Geogr. Nacional and computation grid with 64 zones for the north (bottom left) and surrounded (bottom right) field

Grahic Jump Location
Fig. 5

Flux map on the PS10 receiver panels on March 21 at noon, obtained with a central aiming on the receiver aperture for different solar field zones. Results show heat flux distributions corresponding to heliostats in zones 1–2 (left) and zones 61–62 (right), see Fig. 3.

Grahic Jump Location
Fig. 6

Heat flux on PS10 receiver with the reference aiming strategy on March 21 at 12 p.m.

Grahic Jump Location
Fig. 7

Flux map on the PS10 receiver panels obtained with aiming strategy 1 (a), strategy 5 (b), and strategy 6 (c)

Grahic Jump Location
Fig. 8

Influence of the aiming strategy on spillage losses. Plots show the increase in spillage for the optimum strategy (strategy 6) with respect to the base aiming (strategy 1). Results correspond to the PS10 and two different sun positions.

Grahic Jump Location
Fig. 9

Flux map on the Gemasolar receiver panels obtained with reference aiming strategy (a), strategy 1 (b), and strategy 6 (c). (Zero deg receiver angle coincides with the south direction.)

Grahic Jump Location
Fig. 10

Comparison between the optimized (left) and reference (right) aiming in terms of spillage increase for Gemasolar at two different sun positions. The size of each heliostat is proportional to the cosine of the incidence angle.

Grahic Jump Location
Fig. 11

Efficiency curves as a function of the zenith angle for different azimuth angles—PS10 (left) and Gemasolar (center) heliostat fields with reference aiming and efficiency gain/loss when aiming strategy 6 is used with respect to the reference aiming strategy (right)




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In