Second Generation Linear Focus Sun Simulator to Test Optical Performance of Parabolic Trough Receivers - OptiRec

This paper presents results from a characterization of DLR’s second generation sun simulator test facility (OptiRec) for determining the optical performance of parabolic trough receivers. The configuration of the test bench is an elliptical mirror trough with flat end mirrors. Solar simulator lamps are situated in one focal line, the receiver in the other focal line. Water at ambient temperature flows through the receiver and allows for a calorimetric measurement of the absorbed power. Compared to the first generation test bench (ElliRec) the mirror material is changed from aluminum to glass, the ellipse size is changed and the handling is improved. Based on 34 measurements of the absorbed power the repeatability for OptiRec measurements is measured to 0.13% (1σ), compared to 0.2% in the ElliRec. Seven receivers from different manufacturers are measured in both test benches yielding agreeing relative optical efficiency with <1.1% deviation. Particular differences are larger than the repeatability, which are attributed to differences in spectra and incidence angles between both test benches

Fast calibration of heliostats

We present the HelioPoint method - a fast airborne method for calibrating entire heliostat fields

SolarPACES Guideline for Heliostat Performance Testing - Release v1.0

Based on national drafts, a group of R&D and industry experts as members of the SolarPACES task III heliostat working group has been working since 2012 on the creation of a guideline for heliostat performance testing. It contains a well-defined list of parameters to describe heliostats and their performance, as well as a list for deriving these parameters. After applying the draft to several industrial and research heliostats (e.g. [1]) and iterative improvements, version 1.0 of the guideline has been released

Konstruktive Auslegung und messtechnische Analyse eines Sonnensimulator-Prüfstandes zur Bewertung der optischen Eigenschaften von Parabolrinnen-Receivern

Durch die fortschreitende Entwicklung werden die Unterschiede der optischen Eigenschaften von Receivern immer geringer, weshalb die Anforderungen an die Messmethodik größer geworden sind. Um diesen nachkommen zu können und mit den bisher gewonnenen Erfahrungen einer angestrebten Standardisierung der Messmethodik näher zu kommen, wurde mit der Entwicklung einer Nachfolgegeneration des Prüfstandes ElliRec mit dem Namen OptiRec begonnen. Ein Teil dieser Entwicklung ist Gegenstand der vorliegenden Arbeit, welche die konstruktive Auslegung sowie eine messtechnische Analyse zum Ziel hat. Im Folgenden wird zunächst ein Überblick der physikalischen und technischen Grundlagen dieser Arbeit in Kapitel 2 gegeben. Der bestehende Sonnensimulator-Prüfstand ElliRec sowie der Planungsstand dessen Nachfolgeprüfstandes werden in Kapitel 3 beschrieben und daraus die Anforderungen an die Entwicklung im Rahmen dieser Arbeit abgeleitet, welche auf dieser Grundlage in Kapitel 4 dargestellt werden. Dabei wird in den Abschnitten 4.1 und 4.2 auf die Auslegung von Tragstruktur und Leitungssystem eingegangen. Eine detaillierte Betrachtung der Auswertemethodik von Messungen wird in Abschnitt 4.3 wiedergegeben. In den Abschnitten 4.4 und 4.5 wird die Auswahl von Messtechnik und Sensorik beschrieben sowie dafür durchgeführte Analysen zu Messunsicherheit und Reproduzierbarkeit dargestellt. Die Entwicklungsergebnisse und gewonnenen Erkenntnisse werden abschließend in Kapitel 5 zusammengefasst

REPA Teststand

Flexible Rohrverbindungn (REPAs) werden in Parabolrinnenanlagen zur Verbindung von feststehenden Rohrleitungen und sich bewegenden Kollektoren eingesetzt. Sie sind durch die hohe Temperatur des Wäremeträgerfludis, wiederholte mechanische Beanspruchung und konzentrierte Solarstrahlung hohen Belastungen ausgesetzt. In einem typischen Solarfeld mit beispielsweise 120 Kollektor-Loops sind 960 REPAs verbaut, deren Investitionssumme sich in Abhängigkeit der technischen Asuführung mit etwa einer Millionen Euro beziffern lässt. Die langfristig zuverl#ssige Funktion dieser Baugruppen sit essentiell für den sicheren und störungsfreien Betreib des Solarfeldes

Accelerated Aging Testing of Parabolic Trough Receivers at DLR

The perfomance of a parabolic torugh reciever is best described by optical efficiency and heat loss power. Their constancy over the lifetime are tested with accelerated aging at DLR. Tests are performed on entire receivers and on small glass samples, where aging of the AR-coating is investigated. Before and after the aging the samples are tested for performanc

Assessment and improvement of optical properties of particles for solid particle receiver

Particle receiver technology is an increasing research field. Researchers are investigating various different types of receivers, such as falling particle receivers, obstructed flow particle receivers, beam down fluidized bed systems, dense particle receivers, or the centrifugal receiver (Ho, 2016). This paper describes the assessment of three samples of commercial available particles (“proppants”) by microscopy and by X-ray diffraction phase analysis: Sintered Bauxite from Saint Gobain (mean diameter 1.2 mm and 0.45 mm), and Carboprop HD from Carbo Ceramics. Analyzed proppants consist of alpha-Al2O3, a glassy phase, and minor amounts of FeAlTiO5 and mullite. Particle samples have been prepared, to measure the reflectivity by a Lambda 950 spectrometer and evaluate the solar absorptance. As-received Bauxite proppants of a reference batch (Saint Gobain) showed a solar absorptance of 87%. To enhance solar absorptance, the particles were coated by inorganic pigments using sol-gel methods, diffusion of coloring ions. Furthermore, a modification of the proppant́s raw material was investigated, such as bauxite power mixed with commercial inorganic pigments and a natural mixture of mainly quartz and clay

Introduction of DLR QUARZ Scope Assessment Label for Independent Product Tests of CSP Key Components

The QUARZ scope assessment label for independent product tests of CSP key components, like parabolic trough receiver or mirrors, is introduced to support the end customer in assessing the product quality and test reports. Two dimensions of quality criteria are defined for assessing product qualification in a standardized manner in QUARZ reports. Aspects of test significance, e.g. number of samples or prototypes vs. independent selection from series production, are covered by the dimension significance category. The completeness of the characterization is represented in the scope level. The scope level compares the tests performed to the tests that could be performed to describe all aspects relevant for a characterization. Goal of the label is to support the end customer of CSP components in assessing the product quality based on the test repor