Project EDITOR


Im Rahmen des internationalen Projekts EDITOR wurde in Limassol, Zypern, eine Parabolrinnenanlage mit Betonwärmespeicher zur Bereitstellung von regelbaren Prozessdampf für einen Getränkehersteller installiert. Die Anlage besteht aus innovativen Komponenten und nutzt ein neues Thermoöl, das auf 425 °C erhitzt werden kann. Das Solar-Institut Jülich führt im Projekt unter anderem Detail-Simulationen für diese Anlage durch und analysiert das Betriebsverhalten sowie die Effizienz.

In einem Workshop am 18. Juni 2019 in Limassol, kurz vor Projektende, sind Interessenten aus Industrie, Forschung und der allgemeinen Öffentlichkeit herzlich eingeladen, das Parabolrinnensystem mit Betonwärmespeicher vor Ort zu besichtigen. Alle Informationen zum Workshop sind im Flyer aufgeführt.

Project leader at Solar-Institut Jülich

Prof. Dr.-Ing. Spiros Alexopoulos

Lehrgebiet Techn. Thermodynamik
Raum N106
T: +49.241.6009 53522
F: +49.241.6009 53570
alexopoulos(at) | Homepage | Veranstaltungen

Executive Board Member – Solar-Institut Jülich

The objective of project EDITOR is to carry out industrial research that demonstrates and verifies the dispatchability and performance of a solar power system designed for continuous operation. The project acronym EDITOR stands for Evaluation of the Dispatchability of a Parabolic Trough Collector System with Concrete Storage.

The system design consists of a mid-sized parabolic trough collector loop combined with a concrete thermal energy storage and is experimentally designed for industrial applications requiring heating or cooling for up to 24 hours. Generally, the solar power system is able to supply heating or cooling on a 24 hour basis if desired by the consumer.

The project partners favoured that the solar power system is to be built in the Republic of Cyprus due to the country’s excellent solar resources.

The current market for solar collectors designed for process heat applications is dominated by systems with maximum operating temperatures of around 250 °C. Whilst these collectors are able to generate process steam effectively, few of these have been equipped with any form of storage. Larger solar collectors designed for supplying energy to electrical generation plants have been equipped with complex molten salt storage systems and can operate at higher temperatures, but to do so often use thermal oils as heat transfer media that are classified as toxic and harmful.

In project EDITOR and for the first time in the history of parabolic trough collector development, the deployed thermal oil will be operated at a temperature beyond 400 °C. This is made possible through the use of a new environmentally friendly silicone based thermal oil, which allows the operating temperature to be raised to 425 °C. A further innovation is the use of a newly developed evacuated heat collecting element (i.e. receiver tube). The heat collecting element was specially designed for the mid-sized parabolic trough collector aperture with the aim to increase the collector efficiency. In order to be able to produce energy on demand, an innovative new concrete storage system will be used and tested. The three year project not only involves the technical activities of building, commissioning and running the solar power system. In addition, it also covers commercial considerations such as the feasibility of scale-up, the identification of future customers and communication regarding this important development with the potential market.

The EDITOR team is made up of 5 partners from three countries, all of whom bring the specific experience of the solar industry required to ensure that the project will be successful. The project partners are:

  • Protarget AG (Cologne, Germany)
  • CADE Soluciones de Ingeniería, S. L. (Albacete, Spain)
  • Cyprus University of Technology (Limassol, Cyprus)
  • German Aerospace Center (Cologne, Germany)
  • Solar-Institut Jülich of the Aachen University of Applied Sciences (Jülich, Germany)

The project duration is from 1 Oct 2015 – 30 Nov 2019 for the Solar-Institut Jülich and from 1 Oct 2015 – 31 August 2019 for all the other partners.

The project partners would like to express their sincere gratitude for the public funds that were received to-date for carrying out the industrial research. The international project EDITOR is funded by the Research Promotion Foundation (RPF) from Cyprus, the Ministry of Economy and Competitiveness (MINECO) from Spain, the Federal Ministry for Economic Affairs and Energy (BMWi) from Germany as well as the Ministry of Innovation, Science and Research of the German State of North Rhine-Westphalia from Germany. SOLAR-ERA.NET, a European network that brings together funding organisations, is supported by the European Commission within the EU Framework Programme for Research and Innovation HORIZON 2020 (Cofund ERA-NET Action, N° 691664 and N°786483).

Responsibilities of project partners

Protarget AG (address: Zeissstrasse 5, 50859 Cologne, Germany):
Protarget is the manufacturer of the parabolic trough collector system. Its main responsibility in the project is the shipping, installation and operation of the PTC system, coordination of all project partners as well as providing information and data to the research partners for their work packages.

Contact person: John Mitchell, mitchell(at)


CADE Soluciones de Ingeniería, S.L. (address: Parque Científico y Tecnológico, Paseo de la Innovación, 3, 02006 Albacete, Spain):
CADE is the manufacturer of the concrete thermal energy storage (C-TES). Its main responsibility in the project is the shipping and installation of the concrete thermal energy storage as well as providing information and data to the research partners for their work packages.

Contact person: Victor Ruiz, vruiz(at)


Cyprus University of Technology (CUT) (address: 30 Arch. Kyprianos Str., 3041 Limassol, Cyprus):
The Cyprus University of Technology (CUT) is the local partner in the project. Its responsibilities are, on the one hand, to support the project networking in Cyprus as well as to identify suitable companies on whose premises the solar plant can be installed for producing process heat. On the other hand, CUT is accompanying the installation of the solar plant and its systems, carries out on-site measurements (including mirror reflectivity) and develops a simulation model of the solar power system in TRNSYS for carrying out annual yield calculations.

Contact person: Prof. Soteris Kalogirou, soteris.kalogirou(at)


German Aerospace Center (DLR) (address: Linder Höhe, 51147 Köln):
The German Aerospace Center’s (DLR) main responsibility in the project is to monitor the heat transfer fluid performance (physico-chemical properties, ageing behaviour and high temperature stability) and to simulate the plant operation using an autoclave lab experiment in order to evaluate the thermal stress on the HTF performance under reference conditions. Furthermore, the DLR will inspect the components that are in contact with the heat transfer fluid.

Contact person: Dr. Christian Jung, Christian.Jung(at)


Solar-Institut Jülich of the Aachen University of Applied Sciences (SIJ) (address: Heinrich-Mussmann-Str. 5, 52428 Jülich, Germany):
The main responsibilities of the Solar-Institut Jülich (SIJ) are to install a weather station on the same site as the solar power system, to provide (lend) a reflectometer to CUT for carrying out mirror reflectivity measurements and to create a simulation model that accurately replicates the real solar power system. The simulation model shall serve for various purposes including improving the PTC plant’s controller, to simulate adjusted operating strategies prior implementation in the process control system of the real plant, and to make accurate energy yield and plant efficiency predictions for scaled-up systems.

Contact person: Prof. Dr.-Ing. Spiros Alexopoulos, alexopoulos(at)


Solar resources of Cyprus and status of fossil-fuel dependence

Cyprus is an island in the Mediterranean Sea and is the second most southern member of the European Union after Malta when comparing the capital city locations. The geographical coordinates of Cyprus’ capital city Nicosia are approx. 35.18°N 33.38°E. The city Limassol, in the south of Cyprus, is the most southern city of the European Union (34.69°N 33.07°E). [1] Cyprus has excellent direct normal irradiance (DNI) resources of up to 2200 kWh/m2 (average value for the time span of 1994-2016), as shown in Figure 1 below, and is therefore an ideal country for conducting an industrial research project in the concentrating solar thermal technology sector.

The climate is Cyprus in summer is very dry. In the hottest months – July and August – the daytime temperature can rise up to 36 °C in the central plain. In the summer months, the amount of precipitation is almost negligible. In this time, however, thunderstorms occasionally form which contribute up to 5 % of the total year’s precipitation. [3]

In the summer months, the daily hours of sunshine are very long in Cyprus. On the longest day in the year (21 June), the sunshine duration is 14h20min. On the shortest day in the year (21 December) the sun shines for 9h40min.

Cyprus has a very strong dependency on fossil fuels. With no own oil fields or petroleum refinery plants, the country is importing all of its petroleum. Most of its electricity is produced by oil-fired power plants. A small portion of electricity is contributed by solar (photovoltaic systems), wind, geothermal and biomass energy sources. [4]

The heat production from renewable energy sources is dominated by solar thermal systems. In the year 2016, a total of 2.926 TJ of heat was produced solely from these systems. In the same year, merely 65 TJ and 186 TJ were produced from geothermal and biomass systems, respectively. [4]


Identification of a process heat consumer in Cyprus

In the beginning of the project, the local project partner Cyprus University of Technology identified several potential companies in the Republic of Cyprus that require process heat. Generally, the solar power system can be deployed by any consumer (e.g. food and beverage industry, hotels, etc.) that requires any form of heating or cooling and has sufficient available ground for installing the system. After site visits in Cyprus, the beverage company KEAN Soft Drinks Ltd in Limassol was chosen for installing the solar power system on their site. The location of the city of Limassol is indicated by the red dot in the Google Maps image below.

Solar power plant design

At first, the KEAN manufacturing processes were thoroughly studied in order to identify the most suitable technical implementation of the solar power system. KEAN uses a fossil-fired boiler to produce saturated steam (188°C, 11 barg) for their pasteurising process just before filling the juice into cartons or bottles. The solar power system designed in EDITOR produces up to 5 % of KEAN’s saturated steam demand, which leads to a reduced consumption of fossil-fuel.

The plant’s main components are listed below:

  • two-row PTC field with a total length of 96 m
  • two-module concrete thermal energy storage
  • kettle-type boiler
  • thermal oil pump

The PTC’s aperture of 3 m falls into the category of mid-sized collectors. This lead to the need of the development of a novel heat collecting element (HCE) whose diameter is specially adapted to the collector’s aperture in order to maximise the collector’s efficiency. Furthermore, the plant deploys a newly developed thermal oil called HELISOL XA which can be heated to 425 °C. The C-TES has a capacity of 600 kWh allowing on-demand and continuous supply of steam.

A schematic of the solar power system at KEAN is shown in Figure 2 below.

Installation of the solar power system

Construction started in 2017 and was completed in the summer of 2018. Figures 3-5 show photos of the solar power plant during the installation and commissioning phase.

News, Publications, Student Jobs


[Updated 06.06.2019]

On 18th June 2018, the project partners are hosting a workshop in Limassol, Cyprus, to present the solar power system and to provide information to anyone who is interested in this project. Whether you are a company representative, a researcher or member of the public, anyone is welcome to visit.

All information regarding the workshop available in the Flyer.

If you have further questions please write an email to sattler(at) or vikrama.atti(at)


[Updated 23 October 2018]

Information on a current publication will be posted in the near future.

Student jobs:

[Updated 23 October 2018]

There are currently no open positions at Solar-Institut Jülich.