Germany

The Fraunhofer Society is a German research organization with 67 institutes spread throughout Germany, each focusing on different fields of applied science . It employs around 23,000 people, mainly scientists and engineers, with an annual research budget of about €1.7 billion. Some basic funding for the Fraunhofer Society is provided by the state , but more than 70% of the funding is earned through contract work, either for government-sponsored projects or from industry.It is named after Joseph von Fraunhofer who, as a scientist, an engineer, and an entrepreneur, is said to have superbly exemplified the goals of the society.The organization has seven centers in the United States, under the name “Fraunhofer USA”, and three in Asia. In October 2010, Fraunhofer announced that it would open its first research center in South America.Fraunhofer UK Research Ltd was established along with the Fraunhofer Centre for Applied Photonics, in Glasgow, Scotland, in March 2012. Wikipedia.


Time filter

Source Type

Green M.A.,University of New South Wales | Emery K.,National Renewable Energy Laboratory | Hishikawa Y.,Japan National Institute of Advanced Industrial Science and Technology | Warta W.,Fraunhofer Institute for Solar Energy Systems | Dunlop E.D.,European Commission - Joint Research Center Ispra
Progress in Photovoltaics: Research and Applications | Year: 2014

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since July 2013 are reviewed. Copyright © 2013 John Wiley & Sons, Ltd.


Green M.A.,University of New South Wales | Emery K.,National Renewable Energy Laboratory | Hishikawa Y.,Japan National Institute of Advanced Industrial Science and Technology | Warta W.,Fraunhofer Institute for Solar Energy Systems | Dunlop E.D.,European Commission - Joint Research Center Ispra
Progress in Photovoltaics: Research and Applications | Year: 2015

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since July 2014 are reviewed. Copyright © 2014 John Wiley & Sons, Ltd.


Green M.A.,University of New South Wales | Emery K.,National Renewable Energy Laboratory | Hishikawa Y.,Japan National Institute of Advanced Industrial Science and Technology | Warta W.,Fraunhofer Institute for Solar Energy Systems | Dunlop E.D.,European Commission - Joint Research Center Ispra
Progress in Photovoltaics: Research and Applications | Year: 2013

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since June 2012 are reviewed. Copyright © 2012 John Wiley & Sons, Ltd.


Zamel N.,Fraunhofer Institute for Solar Energy Systems | Li X.,University of Waterloo | Li X.,Tianjin University
Progress in Energy and Combustion Science | Year: 2013

Multi-phase transport of reactant and product species, momentum, heat (energy), electron and proton in the components of polymer electrolyte membrane (PEM) fuel cells forms the three inter-related circuits for mass, heat (energy) and electricity. These intertwined transport phenomena govern the operation and design, hence the performance, of such cells. The transport processes in the cell are usually determined with their respective effective transport properties due to the porous nature of PEM fuel cell components. These properties include the effective diffusion coefficient for the mass transfer, effective thermal conductivity for heat transfer, effective electronic conductivity for electron transfer, effective protonic conductivity for proton transfer, intrinsic and relative permeability for fluid flow, capillary pressure for liquid water transfer, etc. Accurate determination of these effective transport properties is essential for the operation and design of PEM fuel cells, especially at high current density operation. Thus, it is the focus of intensive research in the recent years. In this article, a review is provided for the determination of these effective transport properties through the various PEM fuel cell components, including the gas diffusion layer, microporous layer, catalyst layer and the electrolyte membrane layer. Given the simplicity of the GDL in structure compared to the other components of the cell, much more work in literature is focused on its transport properties. Hence, its review in this paper is more extensive. Various methods used for the determination of the effective transport properties with and without the presence of liquid water are reviewed, including experimental measurements, numerical modeling and theoretical analyses. Correlations are summarized for these transport properties, where available and further work in this area is provided as a direction for future work. © 2012 Elsevier Ltd. All rights reserved.


Siefer G.,Fraunhofer Institute for Solar Energy Systems | Bett A.W.,Fraunhofer Institute for Solar Energy Systems
Progress in Photovoltaics: Research and Applications | Year: 2014

The temperature dependence of the I-V parameters of different III-V multi-junction concentrator cells at several concentration levels was investigated. Moreover, the influence of spectral changes on the temperature coefficients of multi-junction solar cells was examined. Complete sets of temperature coefficients of a metamorphic Ga0.35In0.65P/Ga0.83In0.17As dual-junction cell, a metamorphic Ga0.35In0.65P/Ga0.83In0.17As/Ge triple-junction cell and a lattice-matched Ga0.50In0.50P/Ga0.99In0.01As/Ge triple-junction cell determined under well-controlled laboratory conditions are reported. Copyright © 2012 John Wiley & Sons, Ltd.


Hoffmann S.,Fraunhofer Institute for Solar Energy Systems | Koehl M.,Fraunhofer Institute for Solar Energy Systems
Progress in Photovoltaics: Research and Applications | Year: 2014

This paper focusses on the physical conditions for a degradation mechanism of photovoltaic modules, known as potential-induced degradation. The analysis was made on several levels. At first, the influence of humidity and temperature on the potential-induced leakage current has been investigated, the second step consists of an accelerated test scheme in a climatic chamber and the third one is outdoor exposure with high voltage stress in two different climate regions. The humidity has a huge impact on the leakage current. Therefore, a test in the climate chamber accelerates the stress found in the field of some orders of magnitude. Copyright © 2012 John Wiley & Sons, Ltd. The impact of temperature, humidity, bias voltage, and contact to the ground on the leakage current was investigated. The temperature dependence obeyed an Arrhenius relation with an activation energy of 75 kJ/mol. The correlation with the bias voltage showed an ohmic behavior. The leakage current differed by orders of magnitude on the ground contact at the module glazing. First, results for the dependence on the ambient climate could be reported. A surprisingly high leakage current was found at rainy days. Copyright © 2012 John Wiley & Sons, Ltd.


Gerteisen D.,Fraunhofer Institute for Solar Energy Systems
Journal of Power Sources | Year: 2010

The present dynamic model is developed to investigate the coupled reaction mechanisms in a DMFC and therein associated voltage losses in the catalyst layers. The model describes a complete five-layer membrane electrode assembly (MEA), with gas diffusion layers, catalyst layers and membrane. The analysis of the performance losses are mainly focused on the electrochemical processes. The model accounts for the crossover of both, methanol from anode to cathode and oxygen from cathode to anode. The reactant crossover results in parasitic internal currents that are finally responsible for high overpotentials in both electrodes, so-called mixed potentials. A simplified and general reaction mechanism for the methanol oxidation reaction (MOR) was selected, that accounts for the coverage of active sites by intermediate species occurring during the MOR. The simulation of the anode potential relaxation after current interruption shows an undershoot behavior like it was measured in the experiment [1]. The model gives an explanation of this phenomenon by the transients of reactant crossover in combination with the change of CO and OH coverages on Pt and Ru, respectively. © 2010 Elsevier B.V. All rights reserved.


Palzer A.,Fraunhofer Institute for Solar Energy Systems | Henning H.-M.,Fraunhofer Institute for Solar Energy Systems
Renewable and Sustainable Energy Reviews | Year: 2014

A clear consensus exists in German society that renewable energy resources have to play a dominant role in the future German energy supply system. However, many questions are still under discussion; for instance the relevance of the different technologies such as photovoltaic systems and wind energy converters installed offshore in the North Sea and the Baltic Sea. Concerns also exist about the cost of a future energy system mainly based on renewable energy. In the work presented here we tried to answer some of those questions. Guiding questions for this study were: (1) is it possible to meet the German energy demand with 100% renewable energy, considering the available technical potential of the main renewable energy resources? (2) what is the overall annual cost of such an energy system once it has been implemented? (3) what is the best combination of renewable energy converters, storage units, energy converters and energy-saving measures? In order to answer these questions, we carried out many simulation calculations using REMod-D, a model we developed for this purpose. This model is described in Part I of this publication. To date this model covers only part of the energy system, namely the electricity and heat sectors, which correspond to about 62% of Germany's current energy demand. The main findings of our work indicate that it is possible to meet the total electricity and heat demand (space heating, hot water) of the entire building sector with 100% renewable energy within the given technical limits. This is based on the assumption that the heat demand of the building sector is significantly reduced by at least 60% or more compared to today's demand. Another major result of our analysis shows that - once the transformation of the energy system has been completed - supplying electricity and heat only from renewables is no more expensive than the existing energy supply. © 2013 Elsevier Ltd.


Kuhn T.E.,Fraunhofer Institute for Solar Energy Systems
Energy and Buildings | Year: 2014

The paper describes procedures for the direct calorimetric measurement of the solar heat gain coefficient g in detail. g is also called SHGC, solar factor, g-value or total solar energy transmittance TSET. All these terms are used synonymously in this document although there are some differences in the details of the definitions of these properties (e.g. different reference wind conditions or reference solar spectra). The document aims to summarize more than 25 years of experience in g-value testing at Fraunhofer ISE, Freiburg, Germany, which includes many different transparent and translucent building materials ranging from transparent insulation materials to daylighting and solar control systems and active solar energy harvesting facade components like building-integrated PV systems (BIPV) or building-integrated solar thermal collectors (BIST). The document focuses on methods for the calorimetric measurement of g under steady-state laboratory conditions. Transient outdoor measurements are beyond the scope of this paper. It also describes the corresponding error analysis and methods to correct experimentally determined values gexp to reference conditions, if it is not possible to reproduce the reference boundary conditions exactly in the laboratory. © 2014 Elsevier B.V. All rights reserved.


Dirnberger D.,Fraunhofer Institute for Solar Energy Systems
IEEE Journal of Photovoltaics | Year: 2014

Standard testing condition power of PV modules, especially thin-film modules, is not a constant value. Exposure to irradiance and temperature, as well as electrical bias and dark storage, cause changes in STC power, which complicate the interpretation of quality assurance measurements and tests. This paper presents a literature review and summarizes current knowledge of metastability and stability problems of PV modules with focus on their influence on quality assurance, especially the verification of rated module power. Three groups of thin-film PV technologies are addressed: amorphous silicon, cadmium telluride (CdTe), and chalcopyrite technologies (CIGS). Amorphous silicon is affected mostly by light-induced degradation and seasonal annealing, whereas sensitivity to dark storage is the most relevant effect for CdTe and CIGS PV modules. In conclusion, it is not possible to quantify the impact of specific (meta)stability effects on measured STC power for all modules of one technology in general, as there is a strong sensitivity to the exact composure and processing of the modules. With regard to the total uncertainty inherent in the verification of rated power of new modules, this paper introduces the concept of differentiating between measurement-related and module-stability-related uncertainty and suggests a procedure for its determination. © 2011-2012 IEEE.

Loading Fraunhofer Institute for Solar Energy Systems collaborators
Loading Fraunhofer Institute for Solar Energy Systems collaborators