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Loreto Valenzuela - One of the best experts on this subject based on the ideXlab platform.

  • A dynamic model for once-through Direct Steam Generation in linear focus solar collectors
    Renewable Energy, 2021
    Co-Authors: João Soares, Armando C. Oliveira, Loreto Valenzuela
    Abstract:

    Abstract Direct Steam Generation in parabolic trough solar collectors is one of the most promising alternatives for replacing the use of thermal oil in solar power plants and process heat. The main advantages are: elimination of Steam generator heat exchangers; use of a non-toxic fluid; operation with power cycle higher temperatures, therefore with higher efficiency. Nevertheless, modelling the two-phase flow heat transfer is a complex task, and there is a lack of modular simulation tools that can easily be replicable for different configurations. In this work, a quasi-dynamic model developed for once-through Direct Steam Generation, using Ebsilon professional software is presented and its results are assessed against experimental results from a test campaign carried out at the DISS test facility. The modelling methodology consists in splitting the solar field into individual components for which modelling and performance are assessed at a detailed level. Quasi-dynamic simulations are feasible by the combination of dynamic components and a time-series, where calculations are carried out for each timestep. The model is highly versatile, both at the system configuration and simulation levels. The model performance was evaluated by comparing simulation and experimental results for different operation stages, i.e. start-up, cool-down, steady and transient solar radiation.

  • Simulation and comparison between fixed and sliding-pressure strategies in parabolic-trough solar power plants with Direct Steam Generation
    Applied Thermal Engineering, 2017
    Co-Authors: Mario Biencinto, Loreto Valenzuela, María José Montes, Lourdes González
    Abstract:

    Abstract Direct Steam Generation in parabolic-trough solar collectors is a promising technology that can improve the efficiency of solar thermal power plants. In this technology, water is heated and evaporated through the solar field to feed a Steam Rankine cycle or an industrial thermal process. Regarding its application for electricity production, two main methods are commonly considered to regulate the Steam pressure at the turbine inlet: fixed and sliding-pressure. In addition, the sliding-pressure method allows two different versions: constant and variable pressure in the condenser. This study aims to simulate the behaviour of a solar thermal power plant with Direct Steam Generation applying the proposed strategies, by comparing their annual performance in terms of electricity production. To this end, a quasi-dynamic model able to address transient conditions with low computational resources has been applied. This model has been developed in the TRNSYS software environment and reproduces the behaviour of both the solar field and the power block of a 38.5 MW e solar thermal power plant. The results of this analysis demonstrate that the use of sliding-pressure strategies for Steam pressure regulation in solar plants with Direct Steam Generation is more advantageous in terms of net electricity production than the fixed-pressure method.

  • 12 – Thermal energy storage concepts for Direct Steam Generation (DSG) solar plants
    Advances in Concentrating Solar Thermal Research and Technology, 2017
    Co-Authors: Loreto Valenzuela
    Abstract:

    Direct Steam Generation (DSG) technology is a proven option for future cost reduction of concentrating solar thermal power plants in comparison with other concentrating solar technologies. The integration of thermal energy storage (TES) in a solar power plant offers an important benefit compared to other alternative power Generation systems because it enables an efficient integration in the electricity grid and provides flexibility in the operation. However, the two-phase heat transfer fluid in DSG solar plants is a major challenge, and innovative TES concepts and new integration solutions are required. This chapter summarizes recent research in TES for DSG solar plants that covers from the use of the existing TES configuration in commercial systems but with optimized power blocks to three-part storage systems that combine the use of sensible and latent heat storage.

  • a quasi dynamic simulation model for Direct Steam Generation in parabolic troughs using trnsys
    Applied Energy, 2016
    Co-Authors: Mario Biencinto, Lourdes González, Loreto Valenzuela
    Abstract:

    This work describes and evaluates a new simulation model for Direct Steam Generation in parabolic-trough solar collectors. In Direct Steam Generation, water is heated and evaporated through a solar field to feed a Steam Rankine cycle or an industrial process. However, the behaviour of the involved multiphase fluid poses some challenges to simulation models. The model explained in this work is based on a steady-state approach but deals with transient conditions such as start-up, shutdown and clouds in a reasonable computing time. A new simulation tool is implemented in the TRNSYS software environment by means of new components that are suitable to be integrated into a whole solar plant model in order to carry out long-term energy production analyses with low computational resources. The main advantages of the new quasi-dynamic approach include fast computation with satisfactory accuracy; consideration of thermal inertia when addressing transient conditions; and flexibility to use different types of collector or solar field configurations. The performance of the model is validated with real experimental data obtained from the DISS solar test loop in Plataforma Solar de Almeria, Spain. This paper describes the modelling approach and summarizes the comparison of simulation results with measurements taken at the DISS facility.

  • modeling Direct Steam Generation in solar collectors with multiphase cfd
    Applied Energy, 2014
    Co-Authors: David H Lobon, Emilio Baglietto, Loreto Valenzuela, Eduardo Zarza
    Abstract:

    The Direct Steam Generation in parabolic-trough solar collectors, using water as heat-transfer fluid, is an attractive option for the economic improvement of parabolic trough technology for solar thermal electricity Generation in the multi megawatt range or industrial process heat supply. But the existence of single-phase and two-phase flow in the absorber pipes of the solar collectors constitutes a challenge for the development of simulation tools and process control schemes suitable for this type of solar technology.

Eduardo Zarza - One of the best experts on this subject based on the ideXlab platform.

  • modeling Direct Steam Generation in solar collectors with multiphase cfd
    Applied Energy, 2014
    Co-Authors: David H Lobon, Emilio Baglietto, Loreto Valenzuela, Eduardo Zarza
    Abstract:

    The Direct Steam Generation in parabolic-trough solar collectors, using water as heat-transfer fluid, is an attractive option for the economic improvement of parabolic trough technology for solar thermal electricity Generation in the multi megawatt range or industrial process heat supply. But the existence of single-phase and two-phase flow in the absorber pipes of the solar collectors constitutes a challenge for the development of simulation tools and process control schemes suitable for this type of solar technology.

  • modeling Direct Steam Generation in solar collectors with multiphase cfd
    Applied Energy, 2014
    Co-Authors: David H Lobon, Emilio Baglietto, Loreto Valenzuela, Eduardo Zarza
    Abstract:

    Abstract The Direct Steam Generation in parabolic-trough solar collectors, using water as heat-transfer fluid, is an attractive option for the economic improvement of parabolic trough technology for solar thermal electricity Generation in the multi megawatt range or industrial process heat supply. But the existence of single-phase and two-phase flow in the absorber pipes of the solar collectors constitutes a challenge for the development of simulation tools and process control schemes suitable for this type of solar technology. The computational fluid dynamic package STAR-CCM+ is used to implement an efficient multiphase model capable of simulating the behavior of Direct Steam Generation in parabolic-trough solar collectors. This work describes the modeling approach and summarizes the comparison of simulation results with the measurements taken at a Direct Steam Generation solar test facility located at the Plataforma Solar de Almeria, Spain.

  • Uncertainty and global sensitivity analysis in the design of parabolic-trough Direct Steam Generation plants for process heat applications
    Applied Energy, 2014
    Co-Authors: Ricardo Silva, Loreto Valenzuela, Manuel Berenguel, Manuel Pérez, Eduardo Zarza
    Abstract:

    Abstract A non-deterministic uncertainty and global sensitivity analysis, based on the Sobol’s method, is developed for a parabolic-trough Direct Steam Generation plant for process heat applications. The objective of this work is to evaluate the robustness of the simulation-based design stage, identifying major modelling sources of uncertainty, as well as quantifying and ranking the relevance of its contribution to the system performance output uncertainty. An important finding obtained from the case considered in this work is that, although the complex characteristics of the Direct Steam Generation two-phase regime introduces additional sources of uncertainty into the low-level modelling stage, the propagation and impact of this uncertainty to system level energy and economic-based design indicators is largely mitigated by higher-level input factors uncertainty. The economic design indicator uncertainty and global sensitivity analysis shows that the lowest relative output uncertainty is obtained by the levelized cost of energy with a coefficient of variation of 4.3%; followed by payback time with 12.1%. The largest contributors of input factors uncertainty to the levelized cost of energy uncertainty are the market discount rate and boiler efficiency, showing total sensitivity indices of 0.67 and 0.23, respectively.

  • control scheme for Direct Steam Generation in parabolic troughs under recirculation operation mode
    Solar Energy, 2006
    Co-Authors: Loreto Valenzuela, Eduardo Zarza, Manuel Berenguel, E F Camacho
    Abstract:

    Electricity production using solar thermal energy is one of the main research areas at present in the field of renewable energies, these systems being characterised by the need of reliable control systems aimed at maintaining desired operating conditions in the face of changes in solar radiation, which is the main source of energy. A new prototype of solar system with parabolic trough collectors was implemented at the Plataforma Solar de Almeria (PSA, South-East Spain) to investigate the Direct Steam Generation process under real solar conditions in the parabolic solar collector field of a thermal power plant prototype. This paper presents details and some results of the application of a control scheme designed and tested for the recirculation operation mode, for which the main objective is to obtain Steam at constant temperature and pressure at the outlet of the solar field, so that changes produced in the inlet water conditions and/or solar radiation will only affect the amount of Steam produced by the solar field. The Steam quality and consequently the nominal efficiency of the plant are thus maintained.

  • control concepts for Direct Steam Generation in parabolic troughs
    Solar Energy, 2005
    Co-Authors: Loreto Valenzuela, Eduardo Zarza, Manuel Berenguel, E F Camacho
    Abstract:

    Abstract A new prototype parabolic-trough collector system was erected at the Plataforma Solar de Almeria (PSA) (1996–1998) to investigate Direct Steam Generation (DSG) in a solar thermal power plant under real solar conditions. The system has been under evaluation for efficiency, cost, control and other parameters since 1999. The main objective of the control system is to obtain Steam at constant temperature and pressure at the solar field outlet, so that changes in inlet water conditions and/or in solar radiation affect the amount of Steam, but not its quality or the nominal plant efficiency. This paper presents control schemes designed and tested for two operating modes, “Recirculation”, for which a proportional-integral-derivative (PI/PID) control functions scheme has been implemented, and “Once-through”, requiring more complex control strategies, for which the scheme is based on proportional-integral (PI), feedforward and cascade control. Experimental results of both operation modes are discussed.

Doerte Laing - One of the best experts on this subject based on the ideXlab platform.

  • Numerical Simulation and Experimental Analysis of a Modular Storage System for Direct Steam Generation
    Heat Transfer Engineering, 2013
    Co-Authors: Andreas Stückle, Doerte Laing, Hans Müller-steinhagen
    Abstract:

    Thermal energy storage is a key technology for the commercialization of solar thermal power plants. This paper gives an overview of a coupled system comprised of concrete regenerators and latent heat storages for Direct Steam Generation, as developed by the German Aerospace Center. Methodologies for an effective transient numerical description of the heat conduction processes inside the single modules and in the whole storage system are presented and their validity is proven by experiments. The presented process has a nominal system pressure of 105.6/80.0 bar for charging/discharging; the corresponding boiling temperatures are 315/295°C. As storage material of the latent heat storage, sodium nitrate with a melting point of 305°C is applied. With the presented models, a prediction of the storage system's temperatures, capacities, and effectiveness is possible. As a result, the design of a 1000-MWhth storage system is presented.

  • TEST AND EVALUATION OF A THERMAL ENERGY STORAGE SYSTEM FOR Direct Steam Generation
    2011
    Co-Authors: Doerte Laing, Carsten Bahl, Michael Fiß, Mirko Meyer-grünefeldt, Matthias Hempel, Martin Eickhoff, Andreas Stückle
    Abstract:

    The test results of a combined storage solution for Direct Steam Generation in CSP plants with a concrete storage for superheating Steam and a PCM storage for evaporating water are reported. The high temperature storage system was built in 2009 in a Direct Steam test loop, constructed at the power plant Litoral of Endesa in Carboneras, Spain. This system has a total capacity of ca. 1000 kWh and is the first demonstration of such a combined storage system for the two phase heat transfer fluid water/Steam. Cycling tests for each storage unit separately and combined testing have proven design expectations. Various operation modes for the PCM storage operation are evaluated.

  • Thermal energy storage for Direct Steam Generation
    Solar Energy, 2011
    Co-Authors: Doerte Laing, Dorothea Lehmann, Carsten Bahl, Thomas Bauer, Wolf-dieter Steinmann
    Abstract:

    Abstract Parabolic trough power plants with Direct Steam Generation are a promising option for future cost reduction in comparison to the SEGS type technology. These new solar thermal power plants require innovative storage concepts, where the two-phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e. for preheating of water and superheating of Steam. A storage system with a total storage capacity of approx. 1 MW h is described, combining a PCM module and a concrete module. The storage modules have been constructed for testing in a DSG-test facility specially erected at a conventional power plant of Endesa in Carboneras (Spain). Commissioning of the storage system started in May 2010; testing under real Steam conditions around 100 bar will begin in August 2010.

  • COMMISIONING OF A THERMAL ENERGY STORAGE SYSTEM FOR Direct Steam Generation
    2010
    Co-Authors: Doerte Laing, Carsten Bahl, Michael Fiß
    Abstract:

    Direct Steam Generation is a promising option for CSP technology, for reducing the costs of solar thermal power Generation. These new solar thermal power plants require adapted storage concepts, where the two-phase heat transfer fluid poses a major challenge. A three-part storage system is proposed for the two phase fluid water/Steam. Concrete storage is used for the process steps involving the transfer of sensible heat – i.e. preheating of water and superheating of Steam – while for the two-phase evaporation a phase change material (PCM) storage will be employed. This technology is being developed by DLR and Ed. Zublin AG. A combined storage solution with a concrete storage for superheating of Steam and a PCM-storage for evaporation of water was build in 2009 in a Direct Steam test loop, set up at the power plant Litoral of Endesa in Carboneras, Spain. This high temperature storage system has a total capacity of ca. 1000 kWh and is the first demonstration of such a combined storage system for the two phase heat transfer fluid water/Steam. Commissioning of this storage system was successfully completed in July 2010, implying first heat-up of the concrete storage to expel the excess water in the concrete, first heat-up of the PCM storage including final filling of the storage with salt and first cycling tests. Results are presented in this paper.

  • Development of a Thermal Energy Storage System for Parabolic Trough Power Plants With Direct Steam Generation
    Journal of Solar Energy Engineering-transactions of The Asme, 2010
    Co-Authors: Doerte Laing, Dorothea Lehmann, Thomas Bauer, Carsten Bahl
    Abstract:

    For future parabolic trough plants Direct Steam Generation in the absorber pipes is a promising option for reducing the costs of solar thermal power Generation. These new solar thermal power plants require innovative storage concepts, where the two phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e. for preheating of water and superheating of Steam. A pinch analysis helps to recognize interface constraints imposed by the solar field and the power block and describes a way to dimension the latent and sensible components. Laboratory test results of a PCM test module with approx. 140 kg NaNO3, applying the sandwich concept for enhancement of heat transfer, are presented, proving the expected capacity and power density. The concrete storage material for sensible heat was improved to allow the operation up to 500 °C for Direct Steam Generation. A storage system with a total storage capacity of approx. 1 MWh is described, combining a PCM module and a concrete module, which will be tested in 2009 under real Steam conditions around 100 bar.

Tobias Hirsch - One of the best experts on this subject based on the ideXlab platform.

  • advancements in the field of Direct Steam Generation in linear solar concentrators a review
    Heat Transfer Engineering, 2014
    Co-Authors: Tobias Hirsch, Jan Fabian Feldhoff, Klaus Hennecke, Robert Pitzpaal
    Abstract:

    Direct Steam Generation in parabolic trough or linear Fresnel collectors represents one interesting technological option for concentrating solar electricity production. Today's state of the art characterized by the first commercial plants in operation is a result of more than 20 years of intensive research on this topic. This article provides a review on the key results from research that includes physical effects like heat transfer and pressure drop in horizontal boiler tubes, plant layout considerations, and thermal storage options. An overview on test and demonstration facilities as well as on commercial plants is given, leading to an outlook on the next Generation of Direct Steam Generation systems.

  • A systematic comparison on power block efficiencies for CSP plants with Direct Steam Generation
    Energy Procedia, 2014
    Co-Authors: Tobias Hirsch, Abdallah Khenissi
    Abstract:

    The increase of the process temperature of concentrating solar power plants above the degradation temperature of thermal oil (400 °C) opens the way for increased power block efficiency and thus reduced cost of electricity production. Direct solar Steam Generation is one technical option to follow this path. The paper presents different power block designs for Direct Steam Generation parabolic trough and linear Fresnel power plants. Based on a systematic modelling approach, results for efficiency gains are derived and compared against a reference case of an oil-based plant. The results show that different reheat configurations are feasible and that efficiency gains in the range from 4 to 6% can be expected based on todays or near future solar collector technology.

  • Advancements in the Field of Direct Steam Generation in Linear Solar Concentrators—A Review
    Heat Transfer Engineering, 2013
    Co-Authors: Tobias Hirsch, Jan Fabian Feldhoff, Klaus Hennecke, Robert Pitz-paal
    Abstract:

    Direct Steam Generation in parabolic trough or linear Fresnel collectors represents one interesting technological option for concentrating solar electricity production. Today's state of the art characterized by the first commercial plants in operation is a result of more than 20 years of intensive research on this topic. This article provides a review on the key results from research that includes physical effects like heat transfer and pressure drop in horizontal boiler tubes, plant layout considerations, and thermal storage options. An overview on test and demonstration facilities as well as on commercial plants is given, leading to an outlook on the next Generation of Direct Steam Generation systems.

  • experiences with Direct Steam Generation at the kanchanaburi solar thermal power plant
    2012
    Co-Authors: Dirk Krüger, Tobias Hirsch, Jan Fabian Feldhoff, Joachim Krüger, Yuvaraj Pandian, Bryan Oconnell, Ramkumar Karthikeyan, Soren Hempel, Karthik Muniasamy, Martin Eickhoff
    Abstract:

    In 2011 the parabolic trough power plant TSE1 has started operation in Thailand. As a novelty it uses the Direct Steam Generation (DSG) process, evaporating and super heating water and Steam Directly in the solar field. During the commissioning phase and first months of operation the start-up procedure has been optimised for the solar field and turbine system resulting in a reduced start-up time. The DSG process can be controlled well in the evaporator and super heater section securing a safe operation of the solar field and keeping live Steam parameters in an acceptable range for the turbine even at fluctuating DNI. Apart from pressure control also control of the plant’s electrical power output is possible, depending on DNI and electricity demand.

  • Steam temperature stability in a Direct Steam Generation solar power plant
    Solar Energy, 2011
    Co-Authors: Jurgen Birnbaum, Robert Pitzpaal, Tobias Hirsch, Jan Fabian Feldhoff, Markus Fichtner, Markus Jocker, Gerhard Zimmermann
    Abstract:

    Abstract Direct Steam Generation (DSG) is one alternative to the current oil-based parabolic trough solar thermal power plants. Within the German research project ITES, the dynamic behavior of a DSG collector field and the interactions with the conventional power block are assessed in detail. A transient solar field model developed by DLR is used to simulate the Steam temperature behavior. Artificial irradiance disturbances as well as real irradiance data are used as input to the system. The resulting main Steam temperature gradients are then analyzed by Siemens considering the standards for Steam turbines. This paper presents the transient simulation results of the Steam temperature as well as the corresponding results of the Steam turbine analysis. It is found that the occurring temperature gradients are challenging for a safe turbine operation, if a conservative control system is used. Therefore, the use of an additional thermal inertia to stabilize the Steam temperature is suggested. Its impact is also analyzed and discussed in this paper.

Martin Eickhoff - One of the best experts on this subject based on the ideXlab platform.

  • experiences with Direct Steam Generation at the kanchanaburi solar thermal power plant
    2012
    Co-Authors: Dirk Krüger, Tobias Hirsch, Jan Fabian Feldhoff, Joachim Krüger, Yuvaraj Pandian, Bryan Oconnell, Ramkumar Karthikeyan, Soren Hempel, Karthik Muniasamy, Martin Eickhoff
    Abstract:

    In 2011 the parabolic trough power plant TSE1 has started operation in Thailand. As a novelty it uses the Direct Steam Generation (DSG) process, evaporating and super heating water and Steam Directly in the solar field. During the commissioning phase and first months of operation the start-up procedure has been optimised for the solar field and turbine system resulting in a reduced start-up time. The DSG process can be controlled well in the evaporator and super heater section securing a safe operation of the solar field and keeping live Steam parameters in an acceptable range for the turbine even at fluctuating DNI. Apart from pressure control also control of the plant’s electrical power output is possible, depending on DNI and electricity demand.

  • Concept comparison and test facility design for the analysis of Direct Steam Generation in once-through mode
    2012
    Co-Authors: Jan Fabian Feldhoff, Mirko Meyer-grünefeldt, Martin Eickhoff, Joachim Krüger, Ramkumar Karthikeyan, Javier Leon Alonso, Matthias Müller, Loreto Valenzuela Gutierrez
    Abstract:

    In addition to the commercial parabolic trough power plants using synthetic oil, the Direct Steam Generation (DSG) is one option for future trough plants. Besides its higher efficiency and lower environmental impact, the overall levelized electricity costs (LEC) will be decisive for the future application of DSG. This paper focuses on the thermodynamic and economic comparison of synthetic oil and DSG plants including the aspect of thermal energy storage – which gains more and more in importance by industry and investors.

  • TEST AND EVALUATION OF A THERMAL ENERGY STORAGE SYSTEM FOR Direct Steam Generation
    2011
    Co-Authors: Doerte Laing, Carsten Bahl, Michael Fiß, Mirko Meyer-grünefeldt, Matthias Hempel, Martin Eickhoff, Andreas Stückle
    Abstract:

    The test results of a combined storage solution for Direct Steam Generation in CSP plants with a concrete storage for superheating Steam and a PCM storage for evaporating water are reported. The high temperature storage system was built in 2009 in a Direct Steam test loop, constructed at the power plant Litoral of Endesa in Carboneras, Spain. This system has a total capacity of ca. 1000 kWh and is the first demonstration of such a combined storage system for the two phase heat transfer fluid water/Steam. Cycling tests for each storage unit separately and combined testing have proven design expectations. Various operation modes for the PCM storage operation are evaluated.

  • Direct Steam Generation in parabolic troughs at 500°C - first results of the REAL-DISS project
    2011
    Co-Authors: Markus Eck, Mirko Meyer-grünefeldt, Martin Eickhoff, Pablo Fontela, Nils Gathmann, Stefan Hillebrand, Jan Schulte-fischedick
    Abstract:

    Parabolic trough solar thermal power plants have the highest maturity of all concentrated solar power systems. Current R&D activities are focusing on further cost reduction of these systems by reducing component costs or by increasing efficiency. One approach to increase efficiency of these systems is to increase the process temperature of the power block. So far the maximum operation temperature is limited to approx. 380°C by the thermal stability of the synthetic oil used in the collector field. Several alternative heat transfer fluids (HTF) are conceivable. At present the most promising candidates are molten salts, compressed gases or water-Steam. In case of water-Steam as the HTF, the process is called Direct Steam Generation (DSG). The main challenges of the Direct Steam Generation are: 1. the development of components such as receiver tubes or flexible tube connections applicable to process temperatures of up to 500°C and pressures of more than 120 bars, 2. the development of a cost effective storage system and 3. the process management of the Direct Steam Generation in a distributed collector field with numerous parallel rows. To develop and demonstrate receiver tubes and flexible tube connections applicable to the mentioned process parameters under real conditions, a joint German-Spanish R&D project was initiated. This paper will present the test set-up and the first experimental results of the project. The development and investigation of the storage system is not subject of this paper. This issue will be presented in a different paper.

  • Direct Steam Generation in parabolic troughs at 500 c first results of the real diss project
    2011
    Co-Authors: Markus Eck, Martin Eickhoff, Pablo Fontela, Nils Gathmann, Stefan Hillebrand, Mirko Meyergrunefeldt, Jan Schultefischedick
    Abstract:

    Parabolic trough solar thermal power plants have the highest maturity of all concentrated solar power systems. Current R&D activities are focusing on further cost reduction of these systems by reducing component costs or by increasing efficiency. One approach to increase efficiency of these systems is to increase the process temperature of the power block. So far the maximum operation temperature is limited to approx. 380°C by the thermal stability of the synthetic oil used in the collector field. Several alternative heat transfer fluids (HTF) are conceivable. At present the most promising candidates are molten salts, compressed gases or water-Steam. In case of water-Steam as the HTF, the process is called Direct Steam Generation (DSG). The main challenges of the Direct Steam Generation are: 1. the development of components such as receiver tubes or flexible tube connections applicable to process temperatures of up to 500°C and pressures of more than 120 bars, 2. the development of a cost effective storage system and 3. the process management of the Direct Steam Generation in a distributed collector field with numerous parallel rows. To develop and demonstrate receiver tubes and flexible tube connections applicable to the mentioned process parameters under real conditions, a joint German-Spanish R&D project was initiated. This paper will present the test set-up and the first experimental results of the project. The development and investigation of the storage system is not subject of this paper. This issue will be presented in a different paper.