HELISOL (R) 5A has been subject to continuous research since 2012. This paper presents at selection of the most relevant test and measurement results gained along the parabolic trough collector application related qualification of this new HTF. HELISOL (R) 5A successfully demonstrated its loop scale functionality achieving the proof of concept at Plataforma Solar de Almeria (PSA) after 480 hours of operation at 425 degrees C. The degradation processes induced formation of low boiling and gaseous products is shown for the aging tests in lab environment and for the loop scale application. In terms of operational safety five key investigations are presented. Three of which include the direct comparison with the commonly used mixture of diphenyl oxide and biphenyl (DPO/BP) the wick flame persistence test, the reaction of HELISOL (R) 5A and DPO/BP with molten salt and the spray ignition test. The other two tests cover the flammability of HELISOL (R) 5A in contact with hot (475 degrees C) surfaces and the worst case scenario of a tube rupture at collector level at 420 degrees C / 17 bar which both don't lead to ignition of the HTF.

The Spanish Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT) through its Plataforma Solar de Almeria (PSA), started a program for testing outdoor every individual component of parabolic trough collectors (PTC), i.e. structure, mirrors, absorber tubes, etc., reproducing real solar conditions as well as in laboratories using accelerated aging chambers or appropriate test loops. A very important part pending of testing in an ad-hoc facility were the collector's inter-connections (ball joints, flexible hoses and hybrid interconnections). In that sense, CIEMAT-PSA and the German Deutsches Zentrum fur Luft- and Raumfahrt e. V. (DLR) agreed to erect a common test bench at PSA. The so called Rotation and Expansion Performing Assembly (REPA) enables specific test as well as accelerated full lifecycle tests under realistic conditions, using silicone or mineral oil based HTFs at temperatures up to 450 degrees C. It was erected and commissioned at PSA and it will start its operation late 2017. The REPA test facility is the result of merging CIEMAT activities in task 14.4 of the European project SFERA-II and DLR activities within the work package 6 of the national German project StaMeP. In a solar power plant with parabolic trough collector (PTC), one of the main technical constraints in the solar field is dealing with the absorber tubes thermal expansion and collectors rotation motion.The non alignment between the collector focal line and the rotation axis is a key point in the construction of this type of solar field. As consequence, the connection interface between the receiver tubes of adjacent PTC in one side and between headers and both loop ends in the other, must be accomplished using elements tested in real conditions able of absorbing that stress.

The technology of parabolic trough collectors (PTC) is used widely in concentrating Solar Power (CSP) plants worldwide. However this type of large-size collectors cannot be officially tested by an accredited laboratory and certified by an accredited certification body so far, as there is no standard adapted to its particularity, and the current published standard for solar thermal collectors are not completely applicable to them. Recently some standardization committees have been working on this technology. This paper aims to give a summary of the standardized testing methodology of large-size PTC for CSP plants, giving the physical model chosen for modeling the thermal performance of the collector in the new revision of standard ISO 9806 and the points still to be improved in the standard draft IEC 62862-3-2. In this paper, a summary of the testing validation performed on one parabolic trough collector installed in one of the test facilities at the Plataforma Solar de Almeria (PSA) with this new model is also presented.

This paper presents a summary of the testing procedure and a validation of the methodology of parabolic trough collector in solar thermal power plants. The applied testing methodology is the one proposed within the Spanish standardization sub-committee AEN/CTN 206/SC117 working group WG2 related to the components for solar thermal power plants. This methodology is also proposed within the international committee IEC TC 117 (Standard draft IEC 62862-3-2 Ed. 1.0). This study is done at Plataforma Solar de Almera (PSA) in Almeria within the European project STAGE-STE. This paper presents the results of the optical and thermal efficiency of a large-size parabolic trough collector. The obtained values are similar to the previous analysis on this collector by PSA. The results of the tracking system have a good accuracy compared to the acceptance angle of the concentrator.

The Plataforma Solar de Almeria (PSA), belonging to the Spanish Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), built in 1996 a parabolic trough test loop for testing a 50m long LS-3 collector under different operating conditions. After finishing the test campaign, the test loop continued its operation up to date. During the last fifteen years it was enlarged several times holding up to three different collectors connected in parallel. Along that time, it has been operating for testing 75m long half collectors prototypes as well as individual modules and the main components that conform a real loop, i.e. absorber tubes, mirrors, support structures, mobile connections or sun-tracking systems. Due to the technology development, the technical requirements and the increasing number of manufacturers, the test loop reached its maximum capacity. As a consequence it was decided to build a new test facility able to handle four complete collectors of commonly used dimensions, i.e. length of 150 m, or even bigger in an East - West oriented field as well as up to four real size collectors loops, as they are in a conventional power plant, in a second field North - South oriented. Both fields will be connected to a Balance Of Plant (BOP) where two independent pumping and cooling systems will feed the respective fields. A collaboration agreement named SolarNOVA was signed between the Spanish Administration and CIEMAT (Contract No. ICT-CEPU2009-0002) and, under its umbrella and the European Union FEDER program, some funds were devoted to the present project, called Parabolic Trough Test loop (PTTL). Earthworks and land preparations started early this year while the procurement already started in 2012. Since the mechanical works will start by the end of May it is expected that at the Conference time the BOP erection must be very advanced. The mounting end is foreseen by December 2013. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Small-sized parabolic-trough collectors, PTCs, are the concentrating solar system technology with the highest potential for thermal energy demand at temperatures up to 250oC. The main applications in this temperature range are industrial process heat production, heat-powered refrigeration and cooling (especially double-effect absorption chillers) and low-temperature heat demand with high consumption rates (domestic hot water, space heating and swimming pool heating). A representative number of such facilities, mainly located in the United States, have been installed during the last three decades. Recently, private business and public institutions have shown a growing interest in this technology. The CAPSOL project undertakes the design, construction and testing of an innovative small-sized PTC for temperatures up to 250oC. Three Spanish partners are participating, the Plataforma Solar de Almería, PSA, the University of Almeria, and the company Composites y Sol S.L. The testing was done in a solar optical and thermal performance test facility, designed and erected at the PSA. After the development and assessment of a first prototype, CAPSOL-01, some improvements were made and a second prototype, CAPSOL-02, was developed and assessed. Commercial version of CAPSOL collector is already on the market. This paper focuses on the final results of this project.

A latent heat thermal storage prototype was tested under real working conditions with steam produced by a parabolic-trough collector test facility at the Plataforma Solar de Almeria. The prototype contained KNO3/NaNO3 eutectic mixture as phase change material (PCM) and expanded graphite fins arranged in a "sandwich configuration" for improving thermal conductivity. In this paper, experimental data such as steam quality, PCM temperature distribution, stored/delivered energy and thermal power have been analyzed for a selected day. A mismatch between steam quality results and the corresponding PCM temperature/time curves has been observed. Furthermore, it has been noted that stored/delivered energy and the resulting thermal power are 40 kW(th)h and 50 kW(th), respectively, and hence, lower than the expected from design parameters. The reasons for these deviations seem to be deficient thermal insulation at the top of the prototype, use of working conditions other than design, and also thermal inertia introduced by excess PCM mass. In this paper, we also demonstrate the applicability of the quasi static model for describing the general performance of a latent thermal energy storage module with a sandwich configuration. In our particular case, the model fits the experimental data quite well when 8 W/mK is taken as the storage medium thermal conductivity. However, for a more accurate description, a sensible heat exchange term should be introduced in the model. (C) 2010 Elsevier Ltd. All rights reserved.

This paper presents a summary of the main results and conclusions achieved in the DISS (Direct Solar Steam) project. The test facility implemented at the Plataforma Solar de Almería (PSA) in 1997–8, the so-called PSA DISS test facility, was operated for more than 3000 h in 1999–2000 and 2001 to investigate the Direct Steam Generation (DSG) process under real solar conditions. The feasibility of the DSG process in horizontal parabolic trough collectors has been proven and an important know how has been acquired by the project partners regarding the thermo-hydraulic parameters of the water/steam flow in DSG solar fields.

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.

The supply and demand of drinking water has become unbalanced in many places due to population growth and changes in weather conditions. About 2000 million people do not have a stable source of drinking water at present. This shortage of drinking water affects many countries in the third world, which also lack conventional energy sources. As these countries usually have salt water resources and a high level of solar insolation which could be used to produce drinking water from brackish or seawater, the Spanish research institution CIEMAT (Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas) and the German DLR (Deutsche Forschungsanstalt fur Luft- und Raumfahrt e.V.) are promoting solar brackish and seawater desalination R&D in the so-called Solar Thermal Desalination (STD) Project.The STD Project forms part of the Industrial Solar Energy Applications Investigation Program, now being carried out at the Platforma Solar de Almeria (PSA), a solar energy research center located in Southern Spain. Project objectives and current status are described in this paper, together with some preliminary results of first phase test campaign evaluation and an overview of system improvements to be implemented in the second phase of the project.

The solar energy research center "Plataforma Solar de Almeria" in Spain launched a joint spanish and german research project on solar thermal desalination early 1988. Since solar desalination is presently not commercially competitive, the aim of this project was to contribute to an optimization of such a system.Presently the experimental installation comprises a 14-effect, stack mounted ME-distiller unit with horizontal tube spray type evaporator cells, comissioned by ENTROPIE (France) in May 1988. The distiller is linked to a parabolic through collector field and a thermocline tank by a low pressure steam generator. Alternatively the distiller can be operated with high pressure steam from a solar power station driving a steam-ejector system for heat recovery.In 1991 the configuration will be extended by introducing an absorption heat pump between the heat input and the rejection end of the distiller. The heat pump will be a double-effect H2O/LiBr-type adapted to this particular application, boosting the plant performance ratio from presently PR = 10.5 (PR = 14 with steam-ejector) to about PR = 24. Manufactured by ENTROPIE the design will be based on research and development at the Physics Department, University of Munich (FRG).