Papers by Joachim Gottsche
High Concentration Solar Collectors
Elsevier eBooks, 2021
LOCAL+ – ein kreislauffähiger Holzmodulbau mit nachhaltigem Energie‐ und Wohnraumkonzept
Bauphysik, Jun 1, 2022
Mit dem Beitrag des Teams der FH Aachen zum SDE 21/22 wird im Projekt LOCAL+ ein kreislauffähiger... more Mit dem Beitrag des Teams der FH Aachen zum SDE 21/22 wird im Projekt LOCAL+ ein kreislauffähiger Holzmodulbau mit einem innovativen Wohnraumkonzept geplant und umgesetzt. Ziel dieses Konzeptes ist die Verringerung des stetig steigenden Wohnflächenbedarfs durch ein Raum‐in‐Raum Konzept. Gebäudetechnisch wird in dem Projekt nicht nur das Einzelgebäude betrachtet, sondern unter Berücksichtigung des Gebäudebestandes wird für das Quartier ein innovatives und nachhaltiges Energiekonzept entwickelt. Ein zentrales Wasserstoffsystem ist für ein Quartier geplant, um den Stromverbrauch aus dem Netz im Winter zu reduzieren. Zentraler Bestandteil des TGA‐Konzepts ist ein unterirdischer Eisspeicher, eine PVT und eine Wärmepumpe mit intelligenter Regelstrategie. Ein Teil des neuen Gebäudes (Design Challenge DC) wird in Wuppertal als Hausdemonstrationseinheit (HDU) präsentiert. Eine hygrothermische Simulation der HDU wurde mit der WUFI‐Software durchgeführt. Da im Innenraum Lehmmodule und ‐platten als Feuchtigkeitspuffer verwendet werden, spielen die Themen Feuchtigkeit, Holzfäule und Schimmelwachstum eine wichtige Rolle.
Enabling industrial plus-energy buildings and improvements by integration of steel components in the building energy concept
Building Simulation Conference proceedings, Sep 1, 2021
Existing buildings often have low energy efficiency standards. For the preparation of retrofits, ... more Existing buildings often have low energy efficiency standards. For the preparation of retrofits, reliable high-quality data about the status quo is required. However, state-of-the-art analysis methods mainly rely on on-site inspections by experts and hence tend to be cost-intensive. In addition, some of the necessary devices need to be installed inside the buildings. As a consequence, owners hesitate to obtain sufficient information about potential refurbishment measures for their houses and underestimate possible savings. Remote sensing measurement technologies have the potential to provide an easy-to-use and automatable way to energetically analyze existing buildings objectively. To prepare an energetic simulation of the status quo and of possible retrofit scenarios, remote sensing data from different data sources have to be merged and combined with additional knowledge about the building. This contribution presents the current state of a project on the development of new and the optimization of conventional data acquisition methods for the energetic analysis of existing buildings solely based on contactless measurements, general information about the building, and data that residents can obtain with little effort. For the example of a single-family house in Morschenich, Germany, geometrical, semantical, and physical information are derived from photogrammetry and quantitative infrared measurements. Both are performed with the help of unmanned aerial vehicles (UAVs) and are compared to conventional methods for energy efficiency analysis regarding accuracy of and necessary effort for input data for building energy simulation. The concept of an object-oriented building model for measurement data processing is presented. Furthermore, an outlook is given on the project involving advanced remote sensing techniques such as ultrasound and microwave radar application for the measurement of additional energetic building parameters.
Solar Tower Power Plant Jülich First Experience with an Open Volumetric Receiver Plant and Presentation of Future Enhancements
High Concentration Solar Collectors
Elsevier eBooks, 2012
Solar thermal concentrated power is an emerging technology that provides clean electricity for th... more Solar thermal concentrated power is an emerging technology that provides clean electricity for the growing energy market. To the solar thermal concentrated power plant systems belong the parabolic trough, the Fresnel collector, the solar dish, and the central receiver system. For high-concentration solar collector systems, optical and thermal analysis is essential. There exist a number of measurement techniques and systems for the optical and thermal characterization of the efficiency of solar thermal concentrated systems. For each system, structure, components, and specific characteristics types are described. The chapter presents additionally an outline for the calculation of system performance and operation and maintenance topics. One main focus is set to the models of components and their construction details as well as different types on the market. In the later part of this chapter, different criteria for the choice of technology are analyzed in detail.
LCA optimal sizing of smart buildings' energy system components considering flexible LCA-grid-footprints
Building Simulation Conference proceedings, Sep 1, 2021
Radar Technoligy For Heliostat Position Conrol
The feasibility study HelioScan of the Solar Institute Julich (SIJ) and the Fraunhofer Institute ... more The feasibility study HelioScan of the Solar Institute Julich (SIJ) and the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) investigates the potential of a new innovative approach, in which the position control of a heliostat field uses the detected position data of a radar system. The currently used systems work with encoders in each heliostat. The new single remote monitoring radar sensor system should be cheaper in terms of manufacturing, installation, operation, calibration and maintenance. The sensor system shall also be applicable regardless of the type of mirror, which increases the range of applications and marketing opportunities. To investigate the suitability of short-wave radar systems, first experiments have been conducted at the experimental solar thermal power plant in Julich (STJ). Radar waves were directed from the research platform of the solar tower to the heliostat field. The reflected signal was evaluated by using high-quality sensors and new computational algorithms. The measurements show that the speed advantages of a surface scan allow a rapid and simultaneous detection of many heliostats, offering the capability of a fast analysis of the whole field. Further details of these first tests and results of the analysis of the heliostat position are presented.
Optical and thermal performance simulation of a micro-mirror solar collector
Energy Reports, Nov 1, 2022
Energy Informatics, Sep 7, 2022
Designing an energy system with the aim of a minimal ecological or economic impact is a very comp... more Designing an energy system with the aim of a minimal ecological or economic impact is a very complex task. The increasing number of possibilities and complexity in energy form, time and space lead to an even more complex problem. These problems are challenging to solve analytically. Instead, mathematical programs can identify optimal solutions (Baños et al. 2011). These programs can use Mixed-Integer-Linear-Problem (MILP) solvers, which can determine the optimal solution concerning their assumptions and model accuracy.
Progress in the development of a laser and camera system for the calibration of heliostat fields of central receiver systems
Nucleation and Atmospheric Aerosols, 2022
Geothermal Energy, Jul 26, 2021
Steel pipes are a common option as a foundation for buildings on unstable ground (Hoback and Trum... more Steel pipes are a common option as a foundation for buildings on unstable ground (Hoback and Truman 1993). The boreholes must be drilled in such cases to ensure the static requirements of the building. It is reasonable to use them for geothermal purposes,
Energy Procedia, 2014
Concentrated sunlight is absorbed in solar thermal power plants by heat resistant absorbers and c... more Concentrated sunlight is absorbed in solar thermal power plants by heat resistant absorbers and converted into usable heat which is transferred to a carrier medium. In solar tower power plants such as the plant in Jülich porous absorbers can reach temperatures up to 1000 °C and higher. At this power plant air as heat transfer medium is sucked in through the absorber and heated up to about 700 °C. The absorber is composed of highly porous ceramic or metal wire structures. The SIJ investigates the optimization of solar absorption and the convective heat transfer to the air using thermo and fluid mechanical calculations. In such simulations the key quantities are the penetration depth of solar radiation κ and the volumetric heat transfer coefficient α v , which indicates how much energy-depending on the volume and temperature difference-is transferred by convection between solid and fluid. The attenuation of the radiation into the depth of the absorber is described generally by an exponential function with parameter κ. This is accompanied by heat transfer to the structure. Existing models of the key quantities have been validated by experimental data.
Springer eBooks, 2008
The open volumetric receiver technology allows the use of air as heat transfer medium at high tem... more The open volumetric receiver technology allows the use of air as heat transfer medium at high temperatures in solar thermal power tower plants. It combines porous ceramic or metallic absorber structures with a strictly modular receiver design. Highly concentrated solar radiation is used to produce hot air as 'firing' for a steam rankine cycle. The advantages of this technology are simplicity and scalability, the ability to include a thermal storage, the low thermal capacity and a high efficiency potential. This receiver technology was developed in various joint projects of research and industry over the past years. It was tested and qualified in the worlds largest test center for concentrating solar power, the Plataforma Solar de Almería (PSA) in Southern Spain with a nominal power of 3 MW incident radiation. In June 2006 it was decided to build a tower power plant with thermal storage in Jülich, Germany, with a design power of 1,5 MWe. The objectives of this plant are to test and demonstrate the solar air technology as a complete system, to develop control and plant management
Research Square (Research Square), Jan 29, 2021
Background: A proven option to found buildings are geothermally activated steel pipes. Statics de... more Background: A proven option to found buildings are geothermally activated steel pipes. Statics determine their dimensions. Energy improvement research focuses on the radius of inner pipe of such coaxial geothermal probes. Mass flow rate is often constant when optimizing inner pipe dimensions. In contrast, in this study flow conditions in outer pipe are constant (constant Reynolds number) to ensure that they not change during optimization. Aim is to maximize net exergy difference for the desired flow type by changing inner pipe radius (after deduction of hydraulic effort). System technology can be selected based on this optimal design and its associated boundary conditions for mass flow and temperatures. Methods: Thermal calculations based on Hellström are carried out to quantify an influence of changing inner pipe radius on thermal yield. A hydraulic optimization of inner pipe radius is performed. Increasing inner pipe radius results in decreasing hydraulic losses in inner pipe but increases hydraulic losses in outer circular ring. Net exergy difference is a key performance indicator to combine thermal and hydraulic effects. Optimization of net exergy difference is carried out for selected scenarios. All calculations are based on various, but fixed Reynolds numbers in the circular ring (Re = [4e3, 1e4, 1e5]), instead of fixed mass flow rates. This ensures fixed flow conditions and no unnecessary high mass flow rate. Results: Optimal inner radius is approximately as large as outer radius considering thermal results. Reynolds numbers are always bigger in inner pipe, due to the constant Reynolds number in circular ring. Both indicate that from a thermal point of view, a high mass flow rate and a high degree of turbulence are particularly important. Hydraulic optimal inner pipe radius is 54 % of outer pipe radius for laminar flow scenarios and 60 % for turbulent flow scenarios. Exergetic optimization shows a predominant influence of hydraulic losses, especially for small temperature gains. Conclusions: Design of coaxial geothermal probes should focus on the hydraulic optimum and take energetic optimum as a secondary criterion to maximize net exergy difference.
Test of a Mini-Mirror Array for Solar Concentrating Systems
ABSTRACT
First Simulation Results for the Hybridization of Small Solar Power Tower Plants
Solar thermal power plants are an emerging technology that provides clean electricity for the gro... more Solar thermal power plants are an emerging technology that provides clean electricity for the growing energy market. To this group of solar thermal systems belongs also the solar tower where a field of two-axis tracking heliostats reflects the solar radiation to the receiver aperture, where concentration ratios up to 1000 are reached. This offers the potential to provide higher steam temperatures to the power cycle or ultimately even high temperature heat to the gas turbine system of a combined cycle power plant. One major option for the accelerated market introduction of solar thermal power technology are solar-fossil hybrid power plants. Their advantage, compared to solar-only systems, lies in low additional investment costs due to an adaptable solar share and reduced technical and economical risks. In this paper a simulation model for the calculation of a hybrid power plant is described. Also the design and performance assessment of solar hybrid tower plants in the power levels of 1-2 MW, is presented. An advanced software tool library is developed for the modelling of such small hybrid power plants. Some first validation and simulation results for parts of a small solar tower power plant are described and discussed.
Plusenergiegebäude 2.0 in Stahlleichtbauweise
Stahlbau, Jun 1, 2019
Ab dem Jahr 2020 soll die Versorgung von Neubauten möglichst weitgehend unabhängig von fossilen E... more Ab dem Jahr 2020 soll die Versorgung von Neubauten möglichst weitgehend unabhängig von fossilen Energieträgern erfolgen. Bei der Konzeption und Realisierung zukünftiger Neubauten werden neben der Senkung des Heizwärmebedarfs auch die Anlagentechnik und Beleuchtung sowie die Nutzung erneuerbarer Energien miteinbezogen werden müssen. Außerdem wird eine ganzheitliche Betrachtung, Bewertung und Optimierung hinsichtlich Energiebedarf und Energiebereitstellung notwendig. Sogenannte Plusenergiegebäude erzeugen dabei mehr Energie, als sie für ihren eigenen Bedarf im Jahresmittel benötigen. Durch Energiemanagement und ‐speicherung im Gebäude wird dabei zusätzlich eine weitere Entlastung der Energieversorgungsinfrastruktur angestrebt (Plusenergie 2.0).
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Papers by Joachim Gottsche