Practical Field Alignment of Parabolic Trough Solar Concentrators

Solar Energy ◽  
2006 ◽  
Author(s):  
Richard B. Diver ◽  
Timothy A. Moss

In this paper a new technique for parabolic trough mirror alignment based on the use of an innovative Theoretical Overlay Photographic (TOP) approach is described. The technique is a variation on methods used to align mirrors on parabolic dish systems. It involves overlay of theoretical images of the Heat Collection Element (HCE) in the mirrors onto carefully surveyed photographic images and adjustment of mirror alignment until they match. From basic geometric principles, for any given viewer location the theoretical shape and location of the reflected HCE image in the aligned mirrors can be predicted. The TOP approach promises to be practical and straightforward and inherently aligns the mirrors to the HCE. Alignment of an LS-2 mirror module on the rotating platform at the National Solar Thermal Test Facility (NSTTF) with the TOP technique along with how it might be implemented in a large solar field is described. Comparison of the TOP alignment to the distant observer approach on the NSTTF LS-2 is presented and the governing equations used to draw the theoretical overlays are developed. Alignment uncertainty associated with this technique is predicted to be less than the mirror slope error.


2006 ◽  
Vol 129 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Richard B. Diver ◽  
Timothy A. Moss

In this paper a new technique for parabolic trough mirror alignment based on the use of an innovative theoretical overlay photographic (TOP) approach is described. The technique is a variation on methods used to align mirrors on parabolic dish systems. It involves overlaying theoretical images of the heat collection element (HCE) in the mirrors onto carefully surveyed photographic images and adjustment of mirror alignment until they match. From basic geometric principles, for any given viewer location the theoretical shape and location of the reflected HCE image in the aligned mirrors can be predicted. The TOP approach promises to be practical and straightforward, and inherently aligns the mirrors to the HCE. Alignment of an LS-2 mirror module on the rotating platform at the National Solar Thermal Test Facility (NSTTF) with the TOP technique along with how it might be implemented in a large solar field is described. Comparison of the TOP alignment to the distant observer approach on the NSTTF LS-2 is presented and the governing equations used to draw the theoretical overlays are developed. Alignment uncertainty associated with this technique is predicted to be less than the mirror slope error.



Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7166
Author(s):  
Alex Brenner ◽  
Tobias Hirsch ◽  
Marc Röger ◽  
Robert Pitz-Paal

The presented review gives reliable information about the currently used measurement instrumentation in parabolic trough fields and recent monitoring approaches. The usually built-in measurement equipment in the solar field, clamp-on systems for flexible measurements of temperature and flow, solar irradiance measurements, standard meteorological equipment, laboratory devices for heat transfer fluid analyses and instruments related to the tracking of solar collector assemblies are presented in detail. The measurement systems are reported with their measurement uncertainty, approximate costs and usual installation location for the built-in instrumentation. Specific findings related to the installation and operation of the measurement devices are presented. The usually installed instrumentation delivers a lot of measurements all over the field at the expense of measurement accuracy, compared to special test facility equipment. Recently introduced measurement approaches can improve the standard instrumentation in terms of accuracy, frequency, spatial distribution or can even extend the amount of measurands. The information about available measurands is the basis for future operation and maintenance solutions based on data-driven approaches.



Author(s):  
Men Wirz ◽  
Matthew Roesle ◽  
Aldo Steinfeld

Thermal efficiencies of the solar field of two different parabolic trough concentrator (PTC) systems are evaluated for a variety of operating conditions and geographical locations, using a detailed 3D heat transfer model. Results calculated at specific design points are compared to yearly average efficiencies determined using measured direct normal solar irradiance (DNI) data as well as an empirical correlation for DNI. It is shown that the most common choices of operating conditions at which solar field performance is evaluated, such as the equinox or the summer solstice, are inadequate for predicting the yearly average efficiency of the solar field. For a specific system and location, the different design point efficiencies vary significantly and differ by as much as 11.5% from the actual yearly average values. An alternative simple method is presented of determining a representative operating condition for solar fields through weighted averages of the incident solar radiation. For all tested PTC systems and locations, the efficiency of the solar field at the representative operating condition lies within 0.3% of the yearly average efficiency. Thus, with this procedure, it is possible to accurately predict year-round performance of PTC systems using a single design point, while saving computational effort. The importance of the design point is illustrated by an optimization study of the absorber tube diameter, where different choices of operating conditions result in different predicted optimum absorber diameters.



Author(s):  
Ennio Macchi ◽  
Giampaolo Manzolini ◽  
Paolo Silva

The role of renewable energies and in particular solar energy could be fundamental in future scenarios of worldwide increase of energy demand: thermodynamic solar energy can play an important role in country with high solar radiation. This paper discusses the development and testing of an innovative code for the prediction of thermodynamic performances at nominal conditions and the estimation of costs of the whole plant, for different parabolic trough solar fields. The code allows a preliminary design of the solar field lay-out, the sizing of the main components of the plant and the optimization of the steam cycle. The code, named PATTO (PArabolic Trough Thermodynamic Optimization), allows to separately calculate the thermal efficiency of (i) parabolic trough systems in commerce as well as (ii) combination of components of various commercial systems, in order to exploit different technology solutions: combination of mirrors, receivers and supports. Using the selected parabolic troughs, the plant configuration is then completed by connecting pipes, heat exchangers, the steam cycle, and storage tanks. The code is also flexible in terms of working fluid, temperature and pressure range. Regarding the power block, a conventional steam cycle with super-heater and re-heater sections and up to seven regenerative bleedings is adopted. It is possible to use also simpler configuration as without re-heater or with less regenerative bleedings. Moreover, thanks to simple or sophisticated economic correlations depending on available data, the code calculates the overall investment cost for the considered solar field and the power block. The code performs steady state analysis at nominal conditions, while future developments are planned regarding part load analysis and transient simulations. The model is tested towards real applications and reference values found in literature; in particular, focusing on SEGS VI plant in the USA. Detailed results showing code potentiality, are presented in terms of solar field and power block energy balances, plant auxiliaries, piping and economic analysis.



2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Jürgen Dersch ◽  
Peter Schwarzbözl ◽  
Timo Richert

An existing software tool for annual performance calculation of concentrating solar power and other renewable energy plants has been extended to enable the simulation of solar tower power plants. The methodology used is shown and a demonstrative example of a 50 MWe tower plant in southern Spain is given. The influence of design power and latitude on solar field layout is discussed. Furthermore, a comparison of the tower plant with a 50 MWe parabolic trough and a Linear Fresnel plant at the same site is given.



2001 ◽  
Vol 123 (2) ◽  
pp. 160-163 ◽  
Author(s):  
Rainer Tamme ◽  
Reiner Buck ◽  
Michael Epstein ◽  
Uriyel Fisher ◽  
Chemi Sugarmen

This paper presents a novel process comprising solar upgrading of hydrocarbons by steam reforming in solar specific receiver-reactors and utilizing the upgraded, hydrogen-rich fuel in high efficiency conversion systems, such as gas turbines or fuel cells. In comparison to conventionally heated processes about 30% of fuel can be saved with respect to the same specific output. Such processes can be used in small scale as a stand-alone system for off-grid markets as well as in large scale to be operated in connection with conventional combined-cycle plants. The complete reforming process will be demonstrated in the SOLASYS project, supported by the European Commission in the JOULE/THERMIE framework. The project has been started in June 1998. The SOLASYS plant is designed for 300 kWel output, it consists of the solar field, the solar reformer and a gas turbine, adjusted to operate with the reformed gas. The SOLASYS plant will be operated at the experimental solar test facility of the Weizmann Institute of Science in Israel. Start-up of the pilot plant is scheduled in April 2001. The midterm goal is to replace fossil fuels by renewable or non-conventional feedstock in order to increase the share of renewable energy and to establish processes with only minor or no CO2 emission. Examples might be upgrading of bio-gas from municipal solid waste as well as upgrading of weak gas resources.



2002 ◽  
Vol 124 (2) ◽  
pp. 126-133 ◽  
Author(s):  
Eduardo Zarza ◽  
Loreto Valenzuela ◽  
Javier Leo´n ◽  
H.-Dieter Weyers ◽  
Martin Eickhoff ◽  
...  

The DISS (DIrect Solar Steam) project is a complete R+TD program aimed at developing a new generation of solar thermal power plants with direct steam generation (DSG) in the absorber tubes of parabolic trough collectors. During the first phase of the project (1996-1998), a life-size test facility was implemented at the Plataforma Solar de Almerı´a (PSA) to investigate the basic DSG processes under real solar conditions and evaluate the unanswered technical questions concerning this new technology. This paper updates DISS project status and explains O&M-related experience (e.g., main problems faced and solutions applied) with the PSA DISS test facility since January 1999.



2020 ◽  
Vol 220 ◽  
pp. 113103 ◽  
Author(s):  
Moustafa M. Aboelmaaref ◽  
Mohamed E. Zayed ◽  
Jun Zhao ◽  
Wenjia Li ◽  
Ahmed A. Askalany ◽  
...  


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