Wolf D.,Heliocentris Industry GmbH |
Budt M.,Fraunhofer Institute for Environmental, Safety and Energy Technology
Applied Energy | Year: 2014
Most of the recent approaches on Adiabatic Compressed Air Energy Storage (A-CAES) aim at Thermal Energy Storage (TES) at high temperatures. High TES temperatures together with high pressures intrinsic to CAES are not easy to handle. In order to avoid this technical challenge, we introduce a low-temperature Adiabatic Compressed Air Energy Storage (LTA-CAES) plant. We select and design multistage radial compressors and expanders with single stages rotating with different speeds allowing for intermediate cooling and reheating of the air flow. The proposed LTA-CAES design shows roundtrip efficiencies in the range of 52-60%, slightly lower compared to those envisioned for high temperature A-CAES. However, it can be shown in an economic analysis that its fast start-up characteristics and wide-ranging part load ability overcompensates the lower cycle efficiencies with regard to plant profitability. © 2014 Elsevier Ltd.
Bretz K.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Kabasci S.,Fraunhofer Institute for Environmental, Safety and Energy Technology
Biotechnology and Bioengineering | Year: 2012
The aim of this work was the development of a feed-control for a succinic acid production fed-batch process. The performed batch trials indicated a correlation between succinic acid production and base consumption pH control. Based on the metabolism of Anaerobiospirillum succiniciproducens, a theoretical correlation between base consumption and glucose feed was established and proved in cultivation trials. With the established fed-batch process, the succinic acid yield could be increased to 0.875 (g/g glucose) in comparison to batch processes (0.60) with similar glucose concentrations. Additionally, the results indicate that the osmolarity of the medium has a significant influence on succinic acid production. © 2011 Wiley Periodicals, Inc.
Dresen B.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Jandewerth M.,Fraunhofer Institute for Environmental, Safety and Energy Technology
International Journal of Life Cycle Assessment | Year: 2012
Purpose Spatial analyses in life cycle assessments are hardly ever conducted. The combination of geoinformation systems and life cycle assessments (LCA) databases is a way to realise such complex calculations. By the example of energetic utilisation of biomass via conditioned biogas a geoinformation systems-based calculation tool is presented which combines geodata on biomass potentials, infrastructure, land use, cost and technology databases with analysis tools for the planning of biogas plants to identify the most efficient plant locations, to calculate balances of emissions, biomass streams and costs. Methods The calculations include the impact categories greenhouse gases, acidification, and eutrophication and were tested for the Lower Rhine region and the Altmark region in Germany. The results of the greenhouse gas (GHG) balances are presented. By using only nationwide available datasets, the calculation tool can be used in other regions as well. Results and discussion Balances of individual sites, regional balances and their temporal development can be calculated in geoinformation systems (GIS) using LCA methods. The composition of the substrates varies according to site and catchment area and lead to large variations in plant configurations and the resulting GHG balances and cost structures. Conclusions GIS tools do not only allow the assessment of individual plants, but also the determination of the GHG reduction potential, the biogas potential as well as the necessary investment costs for entire regions. Thus, the exploitation of regional biogas potentials in a way that is sustainable and climate-friendly becomes simple. © Springer-Verlag 2012.
Metz M.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Doetsch C.,Fraunhofer Institute for Environmental, Safety and Energy Technology
Energy | Year: 2012
Due to the rapid increase of wind and photovoltaic generation, flexible storage applications become more important. Electric vehicles are supposed as one option to fill the gap between a fixed energy demand and a stochastic feed in from fluctuating energy sources. But the charging loads will also affect the grid load, since the transport sector contributes considerably to the total energy consumption today. This study examines the conflicting relationship between user mobility and grid support and introduces an approach to simulate large vehicle fleets on the basis of individual driving profiles.9744 driving profiles from the German mobility panel were used within this examination. 958 were classified as potential early adopters for electric vehicles. Those vehicles could provide grid support in 81% of the time, when charging spots are available at home and at work. We simulated the charging loads under the restrictions of the individual mobility for the scenario 2030. Uncoordinated charging will increase the load fluctuations, whereas coordinated charging loads allow load shifting without limiting the mobility. The additional electricity demand is moderate over the next two decades. © 2012 Elsevier Ltd.
Bretz K.,Fraunhofer Institute for Environmental, Safety and Energy Technology
Chemical Engineering and Technology | Year: 2015
Considering glycerol as an inexpensive alternative carbon source, the optimal glycerol concentration for succinic acid production with Anaerobiospirillum succiniciproducens was identified in shake-flask trials. The addition of a defined amount of glucose improved the growth and succinic acid productivity significantly. In fed-batch processes with glycerol as sole substrate, a maximum succinic acid concentration and product substrate yield were obtained. The addition of glucose led to a 2.5-fold increased succinic acid concentration whereas the product substrate yield remained nearly constant. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Daschner R.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Binder S.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Mocker M.,Fraunhofer Institute for Environmental, Safety and Energy Technology
Applied Energy | Year: 2013
The situation on the energy market in the EU countries, especially in Germany, is in a changing process. An increasing amount of wind and solar power plants is feeding renewable, but fluctuating energy into the grid especially in Germany. Thus balancing power is needed. Combined heat and power plants (CHPs) are mostly operating heat driven at the moment. Fraunhofer UMSICHT is researching a new concept of external superheating for CHP with biomass and waste fuels for increasing electrical efficiency and additional storage option for decoupling heat and power generation in order to supply the electrical grid with power on demand. Therefore the main component for this superheating concept, the so-called Pebble-Heater, has been developed. It is a pebble bed regenerator and storage system for high temperatures, which can be used in combined heat and power plants (CHPs). Theoretical examination of the Pebble-Heater performance has been accomplished at the test facilities of Fraunhofer UMSICHT during the last years. Especially the temperature profile inside the pebble bed has been simulated. The results of the Pebble-Heater test rig with a storage capacity of approximately 80. kW. h at temperatures up to 1200. °C are presented in this paper. The temperature profile inside the pebble bed combined with a low pressure drop have shown the potential to implement the Pebble-Heater for high temperature usage. © 2012 Elsevier Ltd.
Huang L.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Doetsch C.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Pollerberg C.,Fraunhofer Institute for Environmental, Safety and Energy Technology
International Journal of Refrigeration | Year: 2010
A paraffin phase change emulsion is a multifunctional fluid consisting of water as the continuous phase and a paraffin as the dispersed phase. It can store or transfer large amounts of thermal energy by using the latent heat capacity of the paraffin during the solid-liquid transition as well as the sensible heat capacity of water and that of the paraffin. This paper presents three paraffin emulsions with different phase transition temperatures: CryoSol plus6, CryoSol plus10 and CryoSol plus20. CryoSol plus6 is foreseen for air-conditioning applications with a freezing peak point of 6 °C, CryoSol plus10 for cooling of buildings with a freezing peak point of 10 °C and CryoSol plus20 for increasing the thermal storage mass of building components with a freezing peak point of 20 °C. © 2010 Elsevier Ltd and IIR. All rights reserved.
Timar G.,Debrecen University |
Timar G.,ETH Zurich |
Blomer J.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Kun F.,Debrecen University |
And 2 more authors.
Physical Review Letters | Year: 2010
We present an experimental and theoretical study of the fragmentation of polymeric materials by impacting polypropylene particles of spherical shape against a hard wall. Experiments reveal a power law mass distribution of fragments with an exponent close to 1.2, which is significantly different from the known exponents of three-dimensional bulk materials. A 3D discrete element model is introduced which reproduces both the large permanent deformation of the polymer during impact and the novel value of the mass distribution exponent. We demonstrate that the dominance of shear in the crack formation and the plastic response of the material are the key features which give rise to the emergence of the novel universality class of fragmentation phenomena. © 2010 The American Physical Society.
Maga D.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Hiebel M.,Fraunhofer Institute for Environmental, Safety and Energy Technology |
Knermann C.,Fraunhofer Institute for Environmental, Safety and Energy Technology
International Journal of Life Cycle Assessment | Year: 2013
Purpose: Information communication technology (ICT) offers the chance of enhancing the efficiency of public services and economic processes. The use of server-based computing is supposed to reduce the energy and material consumption in ICT services. This hypothesis will be investigated and quantified looking at the whole life cycle of the products. In this paper, server-based computing in combination with thin clients (SBCTC) is compared to a typical desktop PC (DPC) workplace over a time period of 5 years. Materials and methods: The LCA method used in this paper is focused on the impact category of global warming potential. The calculations were performed using the Microsoft® Excel-based methodology for ecodesign of energy-related products tool. This tool includes the requirements of energy-related products (Directive 2009/125/EC). Moreover, an input-orientated method - material input per service unit (MIPS) - is applied which allows for an additional comparison between the two ICT solutions. Results and discussion: Electricity consumption could be identified as a crucial environmental impact factor of DPC and SBCTC with both methods. Depending on the user behavior, more than 200 kg CO2e can be saved by switching from DPC to SBCTC. Over 80 kg CO2e can be saved in the material and extraction life cycle stage. The largest savings are achieved in the material category electronics (about 70 kg CO2e). A correlation analysis between the results of global warming potential (GWP) and the MIPS category "air" shows that both indicators GWP and air lead to the same conclusions when evaluating life cycle stages and ICT material categories. Conclusions: Taking into account all assumptions made in this paper, SBCTC saves more than 65 % of greenhouse gas emissions compared to DPC during the entire life cycle. To ensure further profound comparisons of the ICT solutions, current data on the energy demand and detailed information on the composition of the IT products should be made available by industry. © 2012 Springer-Verlag.
Gehrke I.,Fraunhofer Institute for Environmental, Safety and Energy Technology
WIT Transactions on Ecology and the Environment | Year: 2014
Building-integrated water recycling is aimed at saving water in office buildings and housing complexes by separate collections and afterwards biological treatment of the various waste water streams. Moreover, the combination with aquaponics and hydroponics allows for the production of fresh food, namely vegetables and fish, whereby water for irrigation purposes as well as transport costs for vegetables will be saved. The presented research work comprises two stages: (1) the development and implementation of combined water treatment systems at laboratory scale particularly for black water treatment, and (2) field tests at a representative huge housing complex. As result of the first research phase a liquid fertilizer could be produced by means of a combined process concluding a hydrolysis step, sedimentation, followed by microfiltration. The intended relation of the nutrients was nearly achieved. © 2014 WIT Press.