TY - CHAP A1 - Nagel, Sylvio A1 - Mast, Tanja A1 - Holzhammer, Uwe A1 - Eltrop, Ludger T1 - Die Rolle der Bioenergie im Energie- und Mobilitätssystem in Deutschland BT - Ergebnisse einer modellgestützten Systemanalyse T2 - Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009- 507-2 SP - 47 EP - 56 PB - Universität Rostock CY - Rostock ER - TY - JOUR A1 - Ahmed, Arslan A1 - Conti, Fosca A1 - Bayer, Peter A1 - Goldbrunner, Markus T1 - Hydronic Road-Heating Systems BT - Environmental Performance and the Case of Ingolstadt Ramps JF - Environmental and Climate Technologies N2 - Snowfall and ice formation on road surface significantly impact the safety of driving conditions. To resolve this, every year salt and de-icing chemicals are sprinkled on roads. However, use of salts and snow ploughing have environmental as well as economical disadvantages. To resolve these problems, hydronic road heating systems are valid alternatives. Heat transfer fluid, i.e. mixture of ethanol and water, is pumped into a tubular circulation system under the asphalt. By this technology, the road and pavements shall stay ice-free even in times of snowfall and temperatures below the freezing point. The system can also be used to cool the asphalt in case of extreme heat, which – besides the heating effect – could also prevent road from damages in extreme summers. This study aims to compare the environmental impact of use of salts and road-heating system in terms of GHG emissions. To assess the environmental impact, an operational road heating system for a ramp in Ingolstadt, Germany, is considered. A cradle-to-grave analysis technique is used to determine the environmental effects based on a life-cycle assessment (LCA) framework. The analysis includes nine components solemnly responsible for hydronic heating of asphalt surface such as local heating pipe, insulation, pumps, and heat meters. Comparison is performed in terms of relative and total impact over 50-year lifetime of three heated ramps having 1989 m2 surface area in total. The results show that the asphalt and heating-circuit causes the major fraction (65 %) of overall GHG emissions, with total life-time emissions of 28.10 kg CO2 eq./m2 of heated surface. During an operational life of 50 years, road heating systems emit 18 % less CO2 eq./m2 as compared to the use of salts. UR - https://doi.org/10.2478/rtuect-2022-0078 KW - Environmental performance KW - de-icing KW - hydronic road-heating system (HRS) KW - greenhouse gases (GHG) KW - Life cycle assessment (LCA) KW - snow removal Y1 - 2022 UR - https://doi.org/10.2478/rtuect-2022-0078 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-35248 SN - 2255-8837 VL - 26 IS - 1 SP - 1044 EP - 1054 PB - De Gruyter Poland CY - Warsaw ER - TY - JOUR A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Missall, Siegmund A1 - Degembaeva, Nadira A1 - Akmatov, Kuban A1 - Zörner, Wilfried T1 - Energy Profiling of a High-Altitude Kyrgyz Community: Challenges and Motivations to Preserve Floodplain Ecosystems Based on Household Survey JF - Sustainability N2 - The floodplain areas along the Naryn River in Kyrgyzstan are essential as they hold the riparian (local) ecosystems because they provide firewood, pastureland, and areas for recreation and protection against erosion. Due to limited access to adequate, reliable, and sustainable energy services, the rural population usually derived their energy needs from multiple natural energy resources (i.e., firewood, charcoal, agricultural residues, animal dung, and wood branches). This is considered a common and predominant practice in rural Kyrgyzstan. This situation leads to a negative impact on local ecosystem services. In addition to that, the reliance on solid fuels contributes to indoor and outdoor air pollution, which is partially threatening the local ecosystem services. By contrast, the employment of renewable-based energy supply systems would substantially reduce the burden on the environment, which is mainly untapped. To integrate renewable energies, it is important to understand the energy behavior of floodplain communities. In that response, the presented article is the first attempt to capture the energy identity of the floodplain community of Kyrgyzstan based on a quantitative energy-based (on-site) household survey. Furthermore, the present research article synthesizes the driving factors that have a (direct or indirect) impact on the energy and local ecosystem services. In addition, the present article proposes a brief pathway for the sustainable energy transition. The article records the recommendation to integrate renewable energies to preserve the local ecosystems of Kyrgyzstan. UR - https://doi.org/10.3390/su132313086 KW - Central Asia KW - ecosystem services KW - energy pattern KW - energy profiling KW - floodplain community KW - high-altitude KW - household survey KW - Kyrgyzstan KW - renewable energies KW - sustainability Y1 - 2021 UR - https://doi.org/10.3390/su132313086 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-10895 SN - 2071-1050 N1 - This article belongs to the Special Issue "Floodplain Ecology and Sustainable Restoration with Regard to Ecosystem Services" VL - 13 IS - 23 PB - MDPI CY - Basel ER - TY - CHAP A1 - Mast, Tanja A1 - Koller, Maria A1 - Holzhammer, Uwe T1 - Verfügbarkeit und Erlösmöglichkeiten unterschiedlicher Biogasanlagenkonzepte im Smart-Market-Ansatz T2 - Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009- 507-2 SP - 391 EP - 397 PB - Universität Rostock CY - Rostock ER - TY - JOUR A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - The energy situation in Central Asia BT - a comprehensive energy review focusing on rural areas JF - Energies N2 - The northern part of the globe is dominated by industrialisation and is well-developed. For many years, the southern part of the world (South Asia, Africa etc.) has been a target of research concentrating on access to energy (mainly electricity) in rural regions. However, the Central Asian region has not been a focus of energy research compared to South East Asia and Africa. Despite plentiful domestically available energy resources, the energy supply in Central Asia is very unevenly distributed between urban and rural areas. Almost half of the total population of Central Asia lives in rural areas and there is a lack of access to modern energy services to meet primary needs. To analyse the energy situation (i.e., electricity, heating, hot water consumption, cooking, etc.) in rural Central Asia, this paper reviews residential energy consumption trends in rural Central Asian regions as compared to urban areas. Furthermore, the paper illustrates the potential of renewable energies in Central Asia. To perform the study, a qualitative comparative analysis was conducted based on a literature review, data, and statistical information. In summary, the presented article discusses the rural energy situation analytically and provides in-depth insights of Central Asian energy infrastructure. UR - https://doi.org/10.3390/en14102805 KW - Central Asia KW - energy resources KW - rural energy supply KW - energy services KW - renewable energy Y1 - 2021 UR - https://doi.org/10.3390/en14102805 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-10908 SN - 1996-1073 VL - 14 IS - 10 PB - MDPI CY - Basel ER - TY - JOUR A1 - Bugaje, Aminu A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Electric two-wheeler vehicle integration into rural off-grid photovoltaic system in Kenya JF - Energies N2 - In both rural and urban areas, two-wheeler vehicles are the most common means of transportation, contributing to local air pollution and greenhouse gas emissions (GHG). Transitioning to electric two-wheeler vehicles can help reduce GHG emissions while also increasing the socioeconomic status of people in rural Kenya. Renewable energy systems can play a significant role in charging electric two-wheeled vehicles, resulting in lower carbon emissions and increased renewable energy penetration in rural Kenya. As a result, using the Conventional and Renewable Energy Optimization (CARNOT) Toolbox in the MATLAB/Simulink environment, this paper focuses on integrating and modeling electric two-wheeled vehicles (e-bikes) into an off-grid photovoltaic Water-Energy Hub located in the Lake Victoria Region of Western Kenya. Electricity demand data obtained from the Water-Energy Hub was investigated and analyzed. Potential solar energy surplus was identified and the surplus was used to incorporate the electric two-wheeler vehicles. The energy consumption of the electric two-wheeler vehicles was also measured in the field based on the rider’s driving behavior. The modeling results revealed an annual power consumption of 27,267 kWh, a photovoltaic (PV) electricity production of 37,785 kWh, and an electricity deficit of 370 kWh. The annual results show that PV generation exceeds power consumption, implying that there should be no electricity deficit. The results, however, do not represent the results in hourly resolution, ignoring the impact of weather fluctuation on PV production. As a result, in order to comprehend the electricity deficit, hourly resolution results are shown. A load optimization method was designed to efficiently integrate the electric 2-wheeler vehicle into the Water-Energy Hub in order to alleviate the electricity deficit. The yearly electricity deficit was decreased to 1 kWh and the annual electricity consumption was raised by 11% (i.e., 30,767 kWh), which is enough to charge four more electric two-wheeler batteries daily using the load optimization technique. UR - https://doi.org/10.3390/en14237956 KW - Lake Victoria KW - photovoltaic KW - off-grid KW - model KW - electric two-wheeled vehicle KW - Water-Energy Hub KW - CARNOT Y1 - 2021 UR - https://doi.org/10.3390/en14237956 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-11070 SN - 1996-1073 VL - 14 IS - 23 PB - MDPI CY - Basel ER - TY - JOUR A1 - Werner, Melanie A1 - Ehrenwirth, Mathias A1 - Muschik, Sebastian A1 - Trinkl, Christoph A1 - Schrag, Tobias T1 - Operational experiences with a temperature-variable district heating network for a rural community JF - Chemical Engineering & Technology N2 - The potential of utilizing temperature-variable district heating systems in rural areas was investigated. A local district heating system in Germany and the related project NATAR are briefly described; measurement data is evaluated. Operational experiences with a seasonal temperature reduction and consequent advantages for different heat generation systems and heat storages are discussed. The analysis of measurement data reveals a high optimization potential for solar thermal systems in case of an integration both into a low- and a high-temperature storage. Furthermore, a combined heat-and-power plant in combination with a CO2 heat pump promises sector-coupling potential and high electricity self-consumption. UR - https://doi.org/10.1002/ceat.202100114 KW - district heating network KW - low temperature KW - sector coupling Y1 - 2021 UR - https://doi.org/10.1002/ceat.202100114 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-20824 SN - 0930-7516 VL - 46 IS - 3 SP - 482 EP - 490 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Vannahme, Anna A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias T1 - Enhancement of a district heating substation as part of a low-investment optimization strategy for district heating systems JF - Resources N2 - In an ongoing project, low-investment measures for the optimization of district heating systems are analyzed. The optimization strategies are collected in a catalog, which is the core of a guideline. The application of this guideline is demonstrated using two concrete district heating networks as examples. In this study, the improvement of an analog controlled district heating substation by an electronic controller is investigated. High supply temperatures and heat losses are often a challenge in district heating networks. The district heating substations have a major influence on the network return temperatures. The comparison of the two substation setups with analog and electronic controllers is carried out by laboratory measurement. It can be shown that the return temperatures can be reduced by an average of 20 K in winter and transition, as well as 16 K in summer. The district heating network losses are calculated for one of both specific district heating networks. They are calculated from the ratio of network losses to generated energy. The generated energy is the sum of network losses and consumer demand. The thermal losses of the network can be reduced by 3%. The volume flow in the heating network can be reduced to a quarter. Therefore, the pumping energy requirement drops sharply since these changes cubically affect the volume flow UR - https://doi.org/10.3390/resources10050053 KW - district heating substation KW - control KW - optimization KW - local district heating networks KW - non-retrofitted single-family houses KW - thermal test rig Y1 - 2021 UR - https://doi.org/10.3390/resources10050053 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-10951 SN - 2079-9276 VL - 10 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Reiter, Christoph A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Hanby, Victor Ian T1 - A Dynamic Multinode Model for Component-Oriented Thermal Analysis of Flat-Plate Solar Collectors JF - Journal of Solar Energy N2 - A mathematical model of a flat-plate solar collector was developed on the basis of the physical principles of optics and heat transfer in order to determine collector’s component temperatures as well as collector efficiency. In contrast to many available models, the targeted use of this dynamic model is the detailed, theoretical investigation of the thermal behaviour of newly developed or adjusted collector designs on component level, for example, absorber, casing, or transparent cover. The defined model is based on a multinode network (absorber, fluid, glazing, and backside insulation) containing the relevant physical equations to transfer the energy. The heat transfer network covers heat conduction, convection, and radiation. Furthermore, the collector optics is defined for the plane glazing and the absorber surface and also considers interactions between them. The model enables the variation of physical properties considering the geometric parameters and materials. Finally, the model was validated using measurement data and existing efficiency curve models. Both comparisons proved high accuracy of the developed model with deviation of up to 3% in collector efficiency and 1 K in component temperatures. UR - http://dx.doi.org/10.1155/2015/280694 Y1 - 2015 UR - http://dx.doi.org/10.1155/2015/280694 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9637 SN - 2314-6230 VL - 2015 PB - Hindawi Publ. CY - New York; Cairo ER - TY - JOUR A1 - Besner, Rebekka A1 - Mehta, Kedar A1 - Zörner, Wilfried T1 - How to Enhance Energy Services in Informal Settlements? BT - Qualitative Comparison of Renewable Energy Solutions JF - Energies N2 - More than half of the urban population of Sub-Saharan Africa lives in informal housing conditions. While urban areas are, in general, characterized by a high electrification rate, residents of informal settlements are still affected by energy poverty, the use of traditional energy sources and unreliable electricity supply. The aim of the study is to give an overview of different renewable-energybased solutions which are able to improve local energy provision. These are Solar Home Systems, Mini-Grids, and Energy-Hubs. The technologies are compared to another option for improving energy supply, namely Grid Expansion. The analysis is based on 24 Key Performance Indicators, which can be classified into technical, economic, environmental, social, and political dimensions. The selection of indicators is based on the challenges prevalent in informal settlements that impede a comprehensive, sustainable energy supply. The literature-based indices are used to determine which of the four technologies is a suitable solution for minimizing the challenges prevailing in informal settlements. The resulting matrix provides a holistic comparison and serves as a decision aid in selecting the appropriate technology for future projects in informal settlements, depending on local conditions and the needs of the population. The results show that the Energy-Hub is a valid alternative for energy supply improvement in Informal Settlements. UR - https://doi.org/10.3390/en16124687 KW - informal settlements KW - energy access KW - Sub-Saharan Africa KW - Energy-Hub KW - Mini-Grid Y1 - 2023 UR - https://doi.org/10.3390/en16124687 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-37319 SN - 1996-1073 VL - 16 IS - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Kaminski Küster, Kristie A1 - Daniel, Gebbran A1 - Aoki, Alexandre Rasi A1 - Lambert-Torres, Germano A1 - Navarro Gevers, Daniel A1 - Impinnisi, Patricio A1 - da Silva Pinto, Cleverson Luiz T1 - Adoption of Local Peer-to-Peer Energy Markets: Technical and Economical Perspectives for Utilities JF - Energies N2 - Peer-to-peer (P2P) energy markets constitute a promising approach for locally coordinating the increasing amount of distributed energy resources (DERs) in the distribution system. Although the benefits of P2P markets for the prosumers are already well understood, their impact on utilities is not well discussed nor well understood. This hinders the development of regulatory frameworks, which are still needed to allow for the widespread adoption of decentralized energy markets in any interested country. So far, research has been conducted in specific isolated aspects, making it difficult to understand the overall implications for utilities. The present study aims to tackle this research gap by comprehensively evaluating P2P markets’ effects, considering utilities as primary stakeholders. A qualitative roadmap with the overall benefits and challenges of adopting P2P by utilities is outlined to reach this purpose. Technical and economic criteria are assigned for comparing a P2P market to the current regulatory framework. Each criterion is evaluated in a co-simulation platform connecting a market model to a power flow model. Market performance is assessed by revenue analysis, and grid operation indicators evaluate grid performance. Furthermore, network fees are introduced as compensation mechanisms for the net revenue loss. Comparison scenarios encompass network fees and the number of agents, PV, and storage penetration. Results demonstrate that there is no possible benefit for both utilities and prosumers simultaneously if looking exclusively at the financial balance of the market. An equilibrium in benefits for all stakeholders is achievable if non-financial metrics are considered in an integrated market and fee structure analysis. Moreover, results demonstrate that the design of market structures must be sensitive to network configurations and DER penetration changes. This study contributes toward comprehending how the utilities could embrace P2P markets as a feasible solution for grid coordination challenges, opening a new set of questions for further research. UR - https://doi.org/10.3390/en16052364 KW - co-simulation KW - distributed energy resources KW - impact analysis KW - local energy markets KW - microgrids KW - peer-to-peer energy trading Y1 - 2023 UR - https://doi.org/10.3390/en16052364 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-32304 SN - 1996-1073 VL - 16 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Igiligi, Anthony A1 - Vielhauer, Armin A1 - Ehrenwirth, Mathias A1 - Hurm, Christian A1 - Summ, Thorsten A1 - Trinkl, Christoph A1 - Navarro Gevers, Daniel T1 - Assessment of Conservation Voltage Reduction in Distribution Networks with Voltage Regulating Distribution Transformers JF - Energies N2 - The application of voltage reduction in medium and low voltage grids to reduce peak power demand or energy consumption has been implemented since the 1980s using several approaches. Conservation Voltage Reduction (CVR), as one such approach, uses a voltage control device to reduce or increase the voltage setpoint on a busbar, thereby reducing or increasing the amount of active and reactive power supply in the network. Voltage regulation for CVR is always implemented according to established network planning standards in each country. Research in this field has proven that a CVR factor (CVRf) of 0.7–1.5 for peak demand reduction can be achieved. This is an evaluation metric of CVR. The aim of this research is to determine and validate CVRf for peak demand reduction by comparing actual results obtained during regular tap changes with other randomly distributed periods outside tap change operations, using a set of measurement data. It is important to understand CVR deployment capability by evaluating CVR potentials from historical random tap operations before a robust network-wide deployment is introduced. This research provides such guidance. It also provides a novel approach to determining tap changes from voltage measurements using a time-based algorithm. A CVRf ranging from 0.95 to 1.61 was estimated using a measurement dataset from a test field. The result of the entire evaluation shows that the CVRf are smaller during peak PV production and greater during peak demand periods. Further evaluation using statistical hypotheses testing and a control chart was used to validate the evaluation. UR - https://doi.org/10.3390/en16073155 KW - conservation voltage reduction KW - peak power KW - tap change KW - voltage regulating distribution transformers Y1 - 2023 UR - https://doi.org/10.3390/en16073155 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-33449 SN - 1996-1073 VL - 16 IS - 7 PB - MDPI CY - Basel ER - TY - JOUR A1 - El Makroum, Reda A1 - Khallaayoun, Ahmed A1 - Lghoul, Rachid A1 - Mehta, Kedar A1 - Zörner, Wilfried T1 - Home Energy Management System Based on Genetic Algorithm for Load Scheduling: A Case Study Based on Real Life Consumption Data JF - Energies N2 - This paper proposes a home energy management system able to achieve optimized load scheduling for the operation of appliances within a given household. The system, based on the genetic algorithm, provides recommendations for the user to improve the way the energy needs of the home are handled. These recommendations not only take into account the dynamic pricing of electricity, but also the optimization for solar energy usage as well as user comfort. Historical data regarding the times at which the appliances have been used is leveraged through a statistical method to integrate the user’s preference into the algorithm. Based on real life appliance consumption data collected from a household in Morocco, three scenarios are established to assess the performance of the proposed system with each scenario having different parameters. Running the scenarios on the developed MATLAB script shows a cost saving of up to 63.48% as compared to a base scenario for a specific day. These results demonstrate that significant cost saving can be achieved while maintaining user comfort. The addition of supplementary shiftable loads (i.e., an electric vehicle) to the household as well as the limitations of such home energy management systems are discussed. The main contribution of this paper is the real data and including the user comfort as a metric in in the home energy management scheme. UR - https://doi.org/10.3390/en16062698 KW - home energy management KW - load scheduling KW - genetic algorithm KW - user comfort Y1 - 2023 UR - https://doi.org/10.3390/en16062698 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-32284 SN - 1996-1073 VL - 16 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vannahme, Anna A1 - Busch, Jonas A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias T1 - Experimental Study of District Heating Substations in a Hardware-in-the-Loop Test Rig JF - Resources N2 - This study compares two district heating substation systems for implementation in rural district heating networks with non-retrofitted single- and two-family houses. The aim is to determine which system has the potential to provide lower return temperatures and/or lower power peak demand. A hardware-in-the-loop-test rig was utilized to measure the two district heating substations under real operation conditions. This experimental study demonstrates that load balancing of the district heating network is attainable with the district heating substation with storage. This is especially advantageous when there is a high demand for domestic hot water. Overall, both systems yield comparable return temperatures. UR - https://doi.org/10.3390/resources12040043 KW - district heating substation KW - local district heating network KW - non-retrofitted single- and two-family-houses KW - thermal hardware-in-the-loop test rig Y1 - 2023 UR - https://doi.org/10.3390/resources12040043 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-33382 SN - 2079-9276 VL - 12 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Reiter, Christoph A1 - Brandmayr, Sebastian A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Hanby, Victor Ian T1 - Performance Optimisation of Polymeric Collectors by Means of Dynamic Simulation and Sensitivity Analysis JF - Energy Procedia N2 - A dynamic flat-plate collector model for parametric sensitivity studies on polymer-based collector designs was developed. Validation using experimental results of conventional flat-plate collectors showed satisfying results especially regarding the calculation of individual part temperatures of a collector. The model was used to predict system efficiency as well as individual part temperatures in order to analyse a polymeric collector approach in comparison to a conventional collector. The simulation results showed that the fractional energy savings of systems with conventional flat-plate collectors cannot be reached with the analysed polymeric collector approach. Also the stagnation temperatures of more efficient approaches are too high for low-cost polymeric materials. The exemplary analysis of annual temperature loads of the backside insulation for different approaches proved the necessity of careful collector design aiming at temperature reduction for all individual collector parts. UR - https://doi.org/10.1016/j.egypro.2014.02.023 KW - mathematical model KW - simulation KW - flat-plate collector KW - collector efficiency KW - stagnation temperature KW - polymeric materials Y1 - 2014 UR - https://doi.org/10.1016/j.egypro.2014.02.023 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-23625 SN - 1876-6102 N1 - Part of special issue: "Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013)" VL - 2014 IS - 48 SP - 181 EP - 191 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mehta, Kedar A1 - Zörner, Wilfried T1 - Cracking the code: mapping residential building energy performance in rural Central Asia through building typologies JF - SN Applied Sciences N2 - AbstractBuildings in rural Central Asia have unique characteristics as they were built during the Soviet era (during 1950–1960) without any energy efficiency measures. The special and aged building stock pose a crucial challenge on energy security and energy supply. However, accurate scientific data on their energy usage is lacking, highlighting a research gap about robust and validated methodology to determine the energy use of rural Central Asian buildings. In response to this need, this research paper proposes a set of generalised residential building typologies for rural Central Asia, with a focus on Kyrgyzstan. The study combines quantitative and qualitative methods, including household surveys, energy demand modelling, EnergyPlus simulations, and result validation. It derives energy-based building typologies from construction year and building envelope characteristics. Through numerous validated simulations, it was identified that the heat demand for rural Kyrgyz houses is 3–5 times here compared to European houses (250–400 kWh/m2). The study revealed the estimated heat demand for homes in rural Kyrgyzstan, indicating a significant potential for improving building energy efficiency in the region. These results can inform specific approaches, such as building renovation plans, energy certification, and renovation strategies. Furthermore, the validated methodology introduced offers opportunities for researchers in the field of building energy efficiency and can be applied to similar regions in Central Asia with comparable building stocks and climates. UR - https://doi.org/10.1007/s42452-023-05607-1 Y1 - 2023 UR - https://doi.org/10.1007/s42452-023-05607-1 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-41536 SN - 2523-3971 VL - 5 IS - 12 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Summ, Thorsten A1 - Oyinlola, Muyiwa A1 - Khattak, Sanober A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Statistical analysis of solar thermal collectors in the Solar Keymark Database JF - Sustainable Energy Technologies and Assessments N2 - Experimental, analytical, or numerical investigations are ordinarily conducted to reveal optimisation potential for solar thermal collectors. At the same time, the ‘Solar Keymark Database’ contains more than 2,000 test reports from certified laboratories featuring properties including thermal efficiency, dimensions, or optical properties. This dataset offers untapped potential for statistical analyses as an alternative optimisation approach. Hence, this paper aims to provide a) the first statistical findings of solar thermal collector properties listed in the Solar Keymark Database and b) insights into statistical relations between these properties. The key correlations observed from the analysis of flat-plate collectors were between efficiency and both gross height (R = 0.30) and gross area (R = 0.27). We concluded that preferable collector designs may be featured with larger area to height ratios. The analyses of evacuated tube collectors revealed a strong correlation between efficiency and transversal incidence angle modifier (R = -0.65) as a result from different tube spacing. It was noticeable that the quasi-dynamic test method reported significantly higher efficiencies (7.14 percentage points) for evacuated tube collectors, which should be carefully considered for future test procedures. Overall, the statistical analysis was in accordance with conventional bottom-up analyses and revealed insightful dependencies for the present collector data. UR - https://doi.org/10.1016/j.seta.2023.103581 Y1 - 2023 UR - https://doi.org/10.1016/j.seta.2023.103581 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-43981 SN - 2213-1396 VL - 2024 IS - 61 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Summ, Thorsten A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Pischow, Kaj A1 - Greenough, Richard A1 - Oyinlola, Muyiwa T1 - Effect of argon concentration on thermal efficiency of gas-filled insulating glass flat-plate collectors JF - Applied Thermal Engineering N2 - Insulating glass flat-plate collectors can save cost by being produced quickly and automatically in insulated glass production facilities, and they can be filled with argon to reduce heat loss. During its lifetime, the collector is likely to lose argon because of gradual material degradation of the sealing. However, information on the influence of the argon concentration on the collector efficiency is limited. Therefore, the objective of this research work was to analyse this effect. A theoretical material property calculation of argon-air mixtures was carried out to determine the convective losses with variable argon concentrations. Thermal collector performance was measured experimentally using an outdoor solar tracker test rig. The results strongly suggest, that the influence of argon concentration on both the convective losses and the thermal efficiency is non-linear. The measurements revealed that an argon concentration of 90 % can increase average thermal performance by 6.7 ± 4.8 percentage points. An increase in argon concentration from 0 % to 50 % has almost twice the effect on average thermal efficiency as an increase from 50 % to 90 %. Concluding from these results, an argon leakage threshold of 2.5 percentage points per year is proposed to avoid disproportionate loss of efficiency over time. UR - https://doi.org/10.1016/j.applthermaleng.2023.120657 KW - Insulating glass KW - Flat-plate collector KW - Argon KW - Gas concentration KW - Efficiency measurement KW - Convective heat transfer Y1 - 2023 UR - https://doi.org/10.1016/j.applthermaleng.2023.120657 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-37875 SN - 1873-5606 SN - 1359-4311 VL - 2023 IS - 230, Part A PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schweizer, Manuel A1 - Stöckl, Martin A1 - Tutunaru, Robin A1 - Holzhammer, Uwe T1 - Influence of heating, air conditioning and vehicle automation on the energy and power demand of electromobility JF - Energy Conversion and Management: X N2 - With the increasing number of electric vehicles in the transport sector, the relevance of accurate energy and power demand predictions of electromobility is growing. Thereby, different vehicle functions, especially heating and air conditioning and vehicle automation, have a significant influence. In accordance with the upcoming Euro-7 emissions standard, the energy consumption for heating even has to be contained in the manufacturer’s consumption data in the future. To increase the accuracy of energy and power demand predictions of electromobility, the energy consumption of vehicle functions such as heating and air conditioning as well as the energy savings through vehicle automation must be considered. This paper presents approaches for modeling and simulation the energy consumption of heating, air conditioning and vehicle automation which can be used as an extension of electric vehicles WLTP (Worldwide Harmonized Light-Duty Vehicles Test Procedure) consumption simulation on the level of vehicle classes. The Germany-wide results of the electric vehicles energy demand for heating and air conditioning on the level of NUTS3-areas (Nomenclature of territorial units for statistics) and vehicle classes show regionally different results and confirm the relevance of the research approach. Vehicle automation results are described on the level of the five SAE automation levels (Society of Automotive Engineers automation levels) and the vehicle classes. The approaches and results can be used for single vehicles or assumed vehicle fleets. UR - https://doi.org/10.1016/j.ecmx.2023.100443 KW - Energy system modelling KW - Electromobility KW - Heating and air conditioning KW - Vehicle automation KW - Energy demand KW - Power demand Y1 - 2023 UR - https://doi.org/10.1016/j.ecmx.2023.100443 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-38868 SN - 2590-1745 VL - 2023 IS - 20 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Need of energy transition at roof of the world BT - Correlative approach to interpret energy identity of high-altitude Central Asian communities JF - Energy for Sustainable Development UR - https://doi.org/10.1016/j.esd.2023.101271 Y1 - 2023 UR - https://doi.org/10.1016/j.esd.2023.101271 SN - 2352-4669 SN - 0973-0826 VL - 2023 IS - 76 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bazzi, Ahmed A1 - El Hafdaoui, Hamza A1 - Khallaayoun, Ahmed A1 - Mehta, Kedar A1 - Ouazzani, Kamar A1 - Zörner, Wilfried T1 - Optimization Model of Hybrid Renewable Energy Generation for Electric Bus Charging Stations JF - Energies N2 - This paper introduces a comprehensive approach for sizing grid-connected hybrid renewable energy systems tailored for electric bus fleet operations. The study involves two main steps. First, a mathematical model that optimizes the configuration of such systems by considering daily electric bus consumption, solar irradiance, wind speed, and biomass potential is formulated. The model utilizes Pareto frontier multi-objective optimization to minimize the net present cost, the cost of energy, and greenhouse gas emissions. Second, the model is rigorously applied and tested in a real-world case study in Fez, Morocco, using HOMER Pro; the case study centers on the daily energy requirements of the buses, estimated at 2.5 megawatt hours per day, with a peak demand of 345 kilowatts. Two scenarios are explored, revealing a discernible trade-off dilemma between the full hybrid renewable energy scenario (Scenario 1) and the grid-connected hybrid renewable energy scenario (Scenario 2). In Scenario 2, the grid-connected hybrid renewable energy system demonstrates a notable 42.8% reduction in the net present cost, totaling USD 984,624. Similarly, the levelized cost of energy experiences a significant decrease, reaching approximately 0.08 USD/kWh, marking a 38.1% reduction. However, this apparent economic advantage is juxtaposed with a critical consideration—an increase in greenhouse gas emissions from null to 330,418 kg/year. UR - https://doi.org/10.3390/en17010053 KW - electric buses KW - HOMER KW - on-site renewable energy generation KW - sustainable transport KW - hybrid renewable energy generation KW - grid-connected renewable energy system KW - electric bus charging station Y1 - 2023 UR - https://doi.org/10.3390/en17010053 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-47109 SN - 1996-1073 VL - 17 IS - 1 PB - MDPI CY - Basel ER - TY - JOUR A1 - Müller, Holger A1 - Brandmayr, Sebastian A1 - Zörner, Wilfried T1 - Development of an evaluation methodology for the potential of solar-thermal energy use in the food industry JF - Energy Procedia N2 - The research project ‘Solar Heat in the Liquid Food Industry’ (part of the FORETA Research Network) focused on the development and optimisation of low-temperature heating systems for the liquid food industry. Its main objectives are in energy efficiency, waste heat recovery and the feasibility of a solar-thermal process heating system. Based on the particular simulation results the overall solar-thermal potentials for German breweries and dairies were determined. In this connection a literature review indicated that most of the potential studies on solar-thermal energy use in the industry or related to specific industrial sectors are based on the total use of low-temperature heat. In opposition to these results, the available and mainly limited roof area was found to be a more important aspect for the solar-thermal potential. Hence, the development of a methodology for a site- specific analysis was necessary. The interconnection of only a few defined evaluation criteria resulted in a more realistic estimation of the potential for a solar-thermal heat supply. UR - https://doi.org/10.1016/j.egypro.2014.02.135 KW - solar-thermal process heat KW - solar-thermal potential KW - food industry Y1 - 2014 UR - https://doi.org/10.1016/j.egypro.2014.02.135 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-23955 SN - 1876-6102 N1 - Part of special issue: "Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013)" VL - 214 IS - 48 SP - 1194 EP - 1201 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hechelmann, Ron-Hendrik A1 - Seevers, Jan-Peter A1 - Otte, Alexander A1 - Sponer, Jan A1 - Stark, Matthias T1 - Renewable Energy Integration for Steam Supply of Industrial Processes: A Food Processing Case Study JF - Energies N2 - This study highlights the CO2,e -emission reduction potentials and related economic consequences for changing steam generation from fossil to renewable. Seven different utility concepts are developed, including a steam accumulator for load management. Peculiarities for the integration of biogas boilers, biomass-fuelled boilers, electrode steam boilers, biomethane-fuelled solid oxide fuel cells, micro gas turbine, solar energy systems, heat pumps and steam accumulators into a steam system with fluctuating steam demand are explained and the energy balance based models for the simulation study are described. The characteristics of batch processes, start up times and part load efficiency are considered via an annual dynamic simulation. Based on a detailed process analysis and dimensioning of the utilities and the accumulator a comprehensive simulation study is conducted for a pet food processing company having an average steam demand of 18,000 MWh at around 9 bar and 3 t/h. The results show that the highest CO2,e -emissions reduction of up to 63% is achieved by the transition to a solid biomass-fuelled boiler system. This leads to an increase of the operating costs by 27.8% UR - https://doi.org/10.3390/en13102532 KW - biomass boilers KW - fuel cell KW - solar thermal KW - electrode boiler KW - steam systems KW - food processing industry KW - decarbonisation KW - energy costs Y1 - 2020 UR - https://doi.org/10.3390/en13102532 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9397 SN - 1996-1073 VL - 13 IS - 10 PB - MDPI CY - Basel ER - TY - CHAP A1 - Mast, Tanja A1 - Hümmer, Benedikt A1 - Holzhammer, Uwe T1 - Smart Markets als marktbasierte Ergänzung zum deutschen Engpassmanagement BT - Konzeptionierung anhand eines Modellbeispiels T2 - 17. Symposium Energieinnovation KW - netzdienliche Flexibilität KW - marktbasiertes Engpassmanagement KW - Smart Market Y1 - 2022 UR - https://www.tugraz.at/events/eninnov2022/nachlese/download-beitraege/stream-a/#c318498 PB - Technische Universität Graz CY - Graz ER - TY - JOUR A1 - Vannahme, Anna A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias T1 - Development and application of a guideline for assessing optimization potentials for district heating systems JF - Energy N2 - Integrating renewable energies into district heating systems has a large potential to reduce CO2-emissions in the heating sector. As district heating systems offer the possibility of incorporating renewable energies into the heat supply, new systems have to be built and the existing networks must be maintained. This study investigates ways to optimize existing district heating systems in order to ensure economic sustainability in the long-term. Previous case studies have elaborated on a variety of optimization measures. However, to date, these measures have neither been collected nor consistently assessed for a wider application range. Therefore, in the study presented here a system for assessing the ecological and economic benefits of optimization measures was developed and applied. The assessment method utilized showed that optimization of district heating consumer substations and adding of a central buffer storage tank has a high optimization potential in comparison to intermittent operation strategy, which has a significantly lower optimization potential. From this information and the transferability data, a district heating operator can determine which optimization measure should be prioritized, which is shown at the end of the paper on an example case. UR - https://doi.org/10.1016/j.energy.2024.131226 Y1 - 2024 UR - https://doi.org/10.1016/j.energy.2024.131226 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-47196 SN - 1873-6785 SN - 0360-5442 VL - 2024 IS - 297 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bachseitz, Michael A1 - Sheryar, Muhammad A1 - Schmitt, David A1 - Summ, Thorsten A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - PV-Optimized Heat Pump Control in Multi-Family Buildings Using a Reinforcement Learning Approach JF - Energies N2 - For the energy transition in the residential sector, heat pumps are a core technology for decarbonizing thermal energy production for space heating and domestic hot water. Electricity generation from on-site photovoltaic (PV) systems can also contribute to a carbon-neutral building stock. However, both will increase the stress on the electricity grid. This can be reduced by using appropriate control strategies to match electricity consumption and production. In recent years, artificial intelligence-based approaches such as reinforcement learning (RL) have become increasingly popular for energy-system management. However, the literature shows a lack of investigation of RL-based controllers for multi-family building energy systems, including an air source heat pump, thermal storage, and a PV system, although this is a common system configuration. Therefore, in this study, a model of such an energy system and RL-based controllers were developed and simulated with physical models and compared with conventional rule-based approaches. Four RL algorithms were investigated for two objectives, and finally, the soft actor–critic algorithm was selected for the annual simulations. The first objective, to maintain only the required temperatures in the thermal storage, could be achieved by the developed RL agent. However, the second objective, to additionally improve the PV self-consumption, was better achieved by the rule-based controller. Therefore, further research on the reward function, hyperparameters, and advanced methods, including long short-term memory layers, as well as a training for longer time periods than six days are suggested. UR - https://doi.org/10.3390/en17081908 KW - reinforcement learning KW - PV-optimization KW - heat pump KW - multi-family building KW - energy-management system Y1 - 2024 UR - https://doi.org/10.3390/en17081908 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-47361 SN - 1996-1073 VL - 17 IS - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - Numeric Simulation-Based Analysis of the Mixing Process in Anaerobic Digesters of Biogas Plants JF - Chemical Engineering & Technology N2 - Stirring systems with two rotational three-bladed propellers were analyzed using computational fluid dynamics. The propellers are located at three heights and seven angles in a tank with 9 m radius. The fluid was characterized by non-Newtonian rheology and simulated by applying the k-ε turbulence model and the standard k-ω model. Reynolds numbers were estimated. High fluid speeds were obtained with the propellers located at a height of 2 m and oriented at 90° with respect to the tank radius. In the top regions of the tank, the fluid velocity was generally less intense and less affected by the angle setting. The configurations identified as good mixing systems showed power consumptions broadly distributed around 30 kW. UR - https://doi.org/10.1002/ceat.201900650 KW - Anaerobic digester KW - Biogas plant KW - Biomass KW - Fluid dynamics KW - Mixing Y1 - 2020 UR - https://doi.org/10.1002/ceat.201900650 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9379 SN - 1521-4125 VL - 43 IS - 8 SP - 1522 EP - 1529 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - Evaluation Criteria and Benefit Analysis of Mixing Process in Anaerobic Digesters of Biogas Plants JF - Environmental and Climate Technologies N2 - A valid method to evaluate decisions of a project proposal is the so-called cost-benefit analysis. Criteria are selected and properly weighted to determine if the project is effective and feasible. The present research study is focused on methodical selection of design parameters to install two propeller mixers inside anaerobic digesters of biogas plants. A cylindrical tank of 1400 m3 was considered. For the model-based optimisation, the substrate was considered as a non-Newtonian fluid with a density of 1090 kg/m3. The Oswald-de Waele power-law model was selected to account for the rheological behaviour of the fluid. Installation parameters of the mixers were rotational angles and heights of the shafts of the two propellers. A computational model was developed to simulate the fluid dynamics depending on the mixing process inside the tank. Several configurations were analysed according to evaluating criteria such as the value of the fluid velocity, its distribution along the three spatial dimensions, and the power consumption to rotate the mixers. The maximum fluid velocity and minimum power consumption were observed when the propellers are located at intermediate height inside the tank and with the shafts perpendicular to the tank radius. With this configuration, the fluid reaches a maximum velocity of 0.28 m/s. According to the investigation, it is evident that mixing systems with propeller shafts deep-seated and parallel to the tank radius should be avoided, both in term of efficiency of the fluid mixing distribution and in term of power consumption. UR - https://doi.org/10.2478/rtuect-2020-0105 KW - Anaerobic digester KW - biomass KW - computational fluid dynamics (CFD) KW - Cost-Benefit Analysis (CBA) KW - evaluation criteria KW - flow velocity KW - full scale biogas digester KW - mixing KW - propeller Y1 - 2020 UR - https://doi.org/10.2478/rtuect-2020-0105 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9274 SN - 2255-8837 VL - 24 IS - 3 SP - 305 EP - 317 PB - De Gruyter Poland CY - Warsaw ER - TY - JOUR A1 - Mehta, Kedar A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Residential Building Construction Techniques and the Potential for Energy Efficiency in Central Asia: Example from High-Altitude Rural Settlement in Kyrgyzstan JF - Energies N2 - Building construction in rural Kyrgyzstan is heavily dominated by earthen buildings. Old and inappropriate residential building structures contribute significantly to high domestic space heating energy consumption. Therefore, it is necessary to understand the relevant building construction techniques. However, the scant information on Kyrgyz building techniques, especially for high-altitude rural settlements, was the prime motivation to perform the presented study. The key objective of the study is to investigate residential building construction techniques in high-altitude rural Kyrgyzstan, and this was to be achieved by house visits during field trips, literature review, and pilot interviews with local people. The analysis enabled the detailed identification of individual building envelopes as well as predominant building materials to be recorded. Based on the assessment, a housing profile was created that represents the typical characteristics of traditional rural Kyrgyz houses. Furthermore, the study demonstrates the potential for energy savings in rural Kyrgyz houses of 50–70%. However, local conditions prevent people from making improvements to all domestic energy efficiency parameters simultaneously. Therefore, the study developed a ‘sequential roadmap’ to reduce domestic space heating demand in different phases based on simulation studies. Existing low-income rural Kyrgyz habitations can use the presented roadmap to reduce domestic space heating demand sequentially to overcome financial barriers and, therefore, contribute to establishing sustainable buildings in Kyrgyzstan. These results may be partially replicated in other Central Asian rural communities depending on their location and building characteristics. UR - https://doi.org/10.3390/en15238869 KW - Central Asia KW - earthen high-altitude houses KW - building construction KW - vernacular buildings KW - energy efficiency KW - cold climate Y1 - 2022 UR - https://doi.org/10.3390/en15238869 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-29752 SN - 1996-1073 VL - 15 IS - 23 PB - MDPI CY - Basel ER - TY - JOUR A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Mapping Potential for Improving Rural Energy Services in Kyrgyzstan: Factors for Achieving Sustainable Development Goals in the Community Context JF - World N2 - Energy is a pivotal element for overall development. Therefore, affordable and clean energy for all (Sustainable Development Goal 7) is one of the important elements. Despite a suitable approach, Kyrgyzstan lags behind to achieve its Sustainable Development Goals by 2030. Improving access to energy can significantly impact the progress of many other sustainable development targets. However, access to reliable, sustainable, and adequate energy is a crucial task in rural Kyrgyzstan. Taking into consideration the energy situation and the importance of the availability of energy services, the overarching aim of the presented article is to map the potential of improving rural energy services to foster overall sustainable development goals. The article presents the most relevant information about rural energy usage behaviour based on three primary pillars: energy demand, energy carrier, and energy sources. In addition, the presented research article synthesises the key driving factors which have a direct or indirect impact on the energy services in rural areas. The summarised data displays a deep insight into a variety of complex and dynamic household energy consumption patterns. The article provides a potential solution nexus to foster improved energy services in rural Kyrgyzstan and therefore to foster the overall sustainable development in Kyrgyzstan. The findings of the article help to formulate a strategy to design rural energy services for policy makers and stockholders. UR - https://doi.org/10.3390/world3030032 KW - energy need KW - rural livelihood KW - energy poverty KW - energy services KW - sustainable energy transition KW - sustainable development goals KW - Kyrgyzstan KW - Central Asia Y1 - 2022 UR - https://doi.org/10.3390/world3030032 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-29518 SN - 2673-4060 VL - 3 IS - 3 SP - 586 EP - 606 PB - MDPI CY - Basel ER - TY - JOUR A1 - Dotzauer, Martin A1 - Pfeiffer, Diana A1 - Lauer, Markus A1 - Pohl, Marcel A1 - Mauky, Eric A1 - Bär, Katharina A1 - Sonnleitner, Matthias A1 - Zörner, Wilfried A1 - Hudde, Jessica A1 - Schwarz, Björn A1 - Faßauer, Burkhardt A1 - Dahmen, Markus A1 - Rieke, Christian A1 - Herbert, Johannes A1 - Thrän, Daniela T1 - How to measure flexibility BT - Performance indicators for demand driven power generation from biogas plants JF - Renewable Energy N2 - Flexible power provision from biogas can significantly contribute to energy systems with high shares of renewables. However, the characteristics and demands for this flexibility are not clearly defined or measured. In this paper eight indicators are defined to shape “flexibility” and perform a downstream investigation of eight research projects focusing on flexible energy provision of biogas plants. The indicators are structured in three dimensions (1) velocity (ramps) by which the system can be modulated, (2) power range (bandwidth) and (3) duration for specific load conditions. Based on these indicators bottlenecks for the flexibility potential were identified. One crucial result shows that short-term flexibility of biogas plants is mainly driven by properties of the combined heat and power unit (velocity and bandwidth). The long-term flexibility depends mainly on gas storage, mode of operation and ability for modulation of the target gas production. UR - https://doi.org/10.1016/j.renene.2018.10.021 KW - Demand-orientated power generation KW - Flexible bioenergy generation KW - Biogas plants KW - Flexibility indicators KW - Gas production modulation KW - Anaerobic digestion Y1 - 2019 UR - https://doi.org/10.1016/j.renene.2018.10.021 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9538 SN - 0960-1481 VL - 134 (2019) SP - 135 EP - 146 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - CFD Modelling of Biomass Mixing in Anaerobic Digesters of Biogas Plants JF - Environmental and Climate Technologies N2 - Cut in greenhouse gas emissions, increment of energy from renewables and improvement in energy efficiency represent the three key targets for future energy systems. Among the available bioenergy technologies, biogas production via biodegradation and anaerobic digestion is a widely applied approach, not only to produce biofuels but also to manage industrial and domestic organic waste. Within the biogas production, a sufficient mixing of the organic mass is a crucial step to ensure high biogas yields by bacteria and enzymes. Measurements of the electric power consumption of biogas plants revealed that the electrical energy demand of the stirrer system has a high share of the total electricity consumption of a biogas plant. Investigations on real biogas digesters to optimize the mixing process are cost and time intensive. Therefore, laboratory prototypes and computational simulations represent promising alternatives to analyse and improve the efficiency of mixing systems. In this paper, a computational fluid dynamics (CFD) model is presented, which is applied to commercial stirring systems. The case of two propeller stirrers, located in diametrically opposite positions in a tank filled with ca. 1400 m3 of substrate is described in detail. For the simulation, the rheology of the fluid is adapted to a biomass with 12 wt % dry matter content and obeying the non-Newtonian generalized Ostwald-de Waele power law. The developed simulation procedure considers the rotation angle of each propeller and its height. A total of 441 mixing configurations are calculated and evaluated in terms of the technical benefit. The investigation reveals that locations of the rotors far away from the bottom and high rotational angles cause advantageous fluid dynamics. UR - https://doi.org/10.2478/rtuect-2019-0079 KW - Anaerobic digester KW - biomass KW - cellulose KW - computational fluid dynamics (CFD) KW - full scale biogas digester KW - laboratory digester KW - mixing KW - rheology KW - viscosity Y1 - 2019 UR - https://doi.org/10.2478/rtuect-2019-0079 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9544 SN - 2255-8837 VL - 23 IS - 3 SP - 57 EP - 69 PB - RTU Press CY - Riga ER - TY - JOUR A1 - Bär, Katharina A1 - Wageneder, Stefanie A1 - Solka, Felix A1 - Saidi, Abdessamad A1 - Zörner, Wilfried T1 - Flexibility Potential of Photovoltaic Power Plant and Biogas Plant Hybrid Systems in the Distribution Grid JF - Chemical Engineering & Technology N2 - The potential of combining biogas and photovoltaic (PV) power plants in hybrid systems in the German distribution grid is analyzed. The focus of the present research is on balancing the intermittent power supply from PV power plants with the controllable power production of combined heat and power (CHP) units of biogas plants within a period of seconds. To achieve an increase of the total energy feed-in of biogas and PV power plants to the electricity grid, a biogas plant energy management system is described. System parameters, such as the variable feed-in of PV power plants or power ramps of the start-up process of controllable biogas plant CHP unit, are described and adapted to the global installed capacity of PV power plant and biogas plants in the German distribution grid. UR - https://doi.org/10.1002/ceat.202000025 KW - Biogas KW - Combined heat and power units KW - Distribution grid KW - Flexible electricity production KW - Photovoltaic power plants Y1 - 2020 UR - https://doi.org/10.1002/ceat.202000025 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9380 SN - 1521-4125 VL - 43 IS - 8 SP - 1571 EP - 1577 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Selleneit, Volker A1 - Mast, Tanja A1 - Holzhammer, Uwe T1 - Method to describe and rate the ability to provide flexibility of residual power providers in electricity grids with a high share of variable renewable energies JF - CIRED - Open Access Proceedings Journal N2 - With an increasing ratio of variable renewable energies in Germany, power supply has to be ensured by providing flexibility from controllable supply and demand energy conversion units. For residual electricity supply, utilities in the industrial sector or flexible biogas plants may be suitable flexibility options. To describe and rate different technologies or utilities in terms of their ability to provide flexibility, a definition of flexibility and an innovative method to describe flexibility considering the grid requirements is elaborated. The method is based on a solid definition of flexibility indicators suitable for all technologies. For an increased flexibility, in many cases, it is reasonable to add supporting technologies like a storage to a utility or biogas combined heat and power (CHP). Such utility configurations can also be described with the elaborated method. The method can also make a valuable contribution to all distribution systems or utility system modellers as it can be taken as a basis for the modelling. In this study, the definition of flexibility indicators is described in detail and used on the example of a biogas CHP plant. UR - https://doi.org/10.1049/oap-cired.2021.0294 KW - Energy resources KW - Distribution networks KW - Thermal power stations and plants KW - Biofuel and biomass resources KW - Power supply quality and harmonics KW - Control of electric power systems Y1 - 2020 UR - https://doi.org/10.1049/oap-cired.2021.0294 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-17043 SN - 2515-0855 VL - 2020 IS - 1 SP - 154 EP - 157 PB - IET CY - Stevenage ER - TY - CHAP A1 - Blasi, Thaís M. A1 - Fernandes, Thelma S. P. A1 - Navarro Gevers, Daniel A1 - Aoki, Alexandre Rasi A1 - Impinnisi, Patricio A1 - da S. Pinto, Cleverson L. A1 - da V. Damasceno, Patricia M. R. T1 - Evaluation of the impacts of renewables sources and battery systems in distribution feeders with different penetration levels T2 - 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) UR - https://doi.org/10.1109/ISGT-LA.2019.8895349 KW - battery energy storage KW - distributed generation KW - opendss KW - penetration levels KW - photovoltaic Y1 - 2019 UR - https://doi.org/10.1109/ISGT-LA.2019.8895349 SN - 978-1-5386-8218-0 PB - IEEE CY - Piscataway ER - TY - JOUR A1 - Slonski, Matthias A1 - Schrag, Tobias T1 - Linear optimisation of a settlement towards the energy-plus house standard JF - Energies N2 - Future buildings will use technologies that are either well-known, innovative, or a combination thereof in order to be environmentally friendly and feasible at the same time. To evaluate and compare such systems through simulation, adaptive tools need to be available. This paper describes a conceived method for planning quarters and settlements. The novelty of this work emerges from the combination of a building simulation with a linear economic optimisation of the energy system, to achieve the energy-plus house standard for a settlement. Furthermore, the tools applied are adaptive or open source. In this article, a hypothetical basic example is given for a predefined idealised settlement, which consists of 132 single-family houses of one building type. The hourly demand for electrical energy and heat is established for three energy-efficiency classes for the building type with a dynamic simulation in MATLAB/SIMULINK using the CARNOT toolbox. This toolbox is also used to calculate the specific electrical energy production by photovoltaics. The components for the energy system of the settlement are implemented in the open source linear optimisation tool URBS. An economic optimum for the energy system of the settlement is found for each of the energy efficiency classes for an accumulated energy demand of the buildings. In this way, a lossless energy hub between the buildings is assumed. The results of the conducted simulations indicate that the optimal ratio of air/water to ground/water heat pumps shifts towards air/water heat pumps with more energy efficient houses. This is due to the lower specific investment costs, which outweigh the operational costs when less energy is required. The lowest costs for the entire energy system are for the one with the most energy efficient settlement. This is the case, as the costs for the higher energy standard of the buildings are not considered in the calculations. The behaviour of the optimisation is tested and discussed through a sensitivity analysis for one efficiency class. By presenting this simple, comprehensible example, an impression of the possible applications for this methodology is conveyed. UR - https://doi.org/10.3390/en12020210 KW - efficiency KW - renewables KW - buildings KW - quarters KW - settlements KW - energy-plus house KW - simulation KW - optimisation Y1 - 2019 UR - https://doi.org/10.3390/en12020210 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-20861 SN - 1996-1073 VL - 12 IS - 2 PB - MDPI CY - Basel ER - TY - CHAP A1 - Ramm, Tobias A1 - Hammel, Carolina A1 - Klärner, Michael A1 - Kruck, Alfons A1 - Schrag, Tobias T1 - Energy storage and integrated energy approach for district heating systems T2 - Energy Procedia N2 - This paper deals with the potential of using the thermal storage capacities within local district heating systems to balance the low and medium voltage grids by the use of heat pumps (HP) and combined heat and power (CHP) plants. The state-of-the-ar of district heating systems as well as the coupling of the heat and power grid is discussed. The research work of the projec NATAR (local heating grids with lowered temperature as provider of balancing power) and the local heating grid of Dollnstein which serves as an use case, are further described. A first analysis of measured data of the district heating system indicates an optimisation potential regarding to the control strategy of the combined heat and power plant as well as the usage of the available thermal storage capacities. UR - https://doi.org/10.1016/j.egypro.2017.09.515 KW - district heating system KW - variable temperatures KW - low-exergy KW - heat pumps KW - coupled energy systems KW - balancing power Y1 - 2017 UR - https://doi.org/10.1016/j.egypro.2017.09.515 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-23501 SN - 1876-6102 VL - 2017 IS - 135 SP - 391 EP - 397 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Riess, Hermann A1 - Brandmayr, Sebastian A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Analysis of the mechanical behaviour of an all-round fully adhesive supported absorber JF - Energy Procedia N2 - This paper discusses the mechanical behaviour of an all-round fully adhesive supported absorber. Previous research is discussed and compared to the author's own results collected using both laboratory tests and simulation. The influence of the finite-element approach (i.e. geometrically linear or non-linear) was compared. The thermal deformation of a hyperstatic absorber was investigated. The relationship between thermal expansion and pressure change in a gas-filled collector is discussed. UR - https://doi.org/10.1016/j.egypro.2014.02.025 KW - Solar collector KW - Absorber KW - Thermal expansion KW - Deformation KW - Mechanical stress KW - Hyperstatic KW - Edge bond Y1 - 2014 UR - https://doi.org/10.1016/j.egypro.2014.02.025 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-23744 SN - 1876-6102 N1 - Part of special issue: "Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013)" VL - 2014 IS - 48 SP - 201 EP - 211 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bader, Tobias A1 - Brandmayr, Sebastian A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Hanby, Victor Ian T1 - Climate Specific Design and Effectiveness of Solar DEC-systems BT - a Methodological Zoning Approach JF - Energy Procedia N2 - The climate specific effectiveness of solar DEC-systems and relevant preferable adaptions of the system design have been so far predominantly analysed based on individual simulation for selected sites. In order to systematically deduce design-specific outline data for the application of the solar DEC-technology at climatically different sites a methodological zoning approach was further developed. A subsequent meteorological analysis for 17 sites mapping the world climate creates a transparent understanding on the activity of the specific system components. This results in a comprehension on the site-specific effectiveness of solar DEC-systems and provides insights on principally relevant and efficient system configurations. UR - https://doi.org/10.1016/j.egypro.2014.02.090 KW - Solar DEC-air-conditioning KW - methodological system design KW - worldwide transferabiltiy KW - climate driven design KW - system effectiveness Y1 - 2014 UR - https://doi.org/10.1016/j.egypro.2014.02.090 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-23614 SN - 1876-6102 N1 - Part of special issue: "Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013)" VL - 2014 IS - 48 SP - 778 EP - 789 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bott, Christoph A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Bayer, Peter T1 - Component-based modeling of ground-coupled seasonal thermal energy storages JF - Applied Thermal Engineering N2 - Seasonal thermal energy storages are considered a central element of modern, innovative energy systems and help to harmonize fluctuating energy sources. Furthermore, they allow for an improved coupling between the electricity and heating sectors. Despite recent improvements of planning processes and enhanced models, significant discrepancies between projected and measured heat losses were revealed. Additional shortcomings of available tools relate to limitations in specifying geometry, internal design, or physical processes. Addressing these drawbacks, this study employs a revised, alternative approach by using a flexible, component-based, model (“STORE”). It allows variable flexible parameterizations to study diverse design scenarios. After introducing relevant seasonal thermal energy storage components, processes and mechanisms, datasets, and evaluation techniques, a plausibility test is presented that applies a common thermal energy storage model for benchmarking. In a test study, the re-use of a circa 1,000 m3 large swimming pool is simulated. STORE is used to investigate performance trends caused by different designs (e.g., insulation thicknesses, materials at individual interfaces). For the plausibility test, the results show a high degree of coverage and good applicability. Further, the results of the test study show a storage efficiency of 12.4% for an uninsulated base case, which can be improved to 69.5% in case of the most complex, highly insulated configuration. Critical trends are revealed, covering reduced peak capacity levels (26.5 to 23.5 MWh) and raised average filling temperatures (39.1 to 45.2 °C). Improved long-term behavior involves reduced environmental impacts due to reduced heating of the ambient soil (+7.9 K compared to +14.1 K after 2 years). General conclusions reveal that an optimal design should initially focus on an external cover of soil and top insulation. However, evaluations should base on multiple parameters depending on the target criteria. This is where the present model is highly useful. The capability of STORE to rapidly analyze a plethora of scenarios proves its high applicability for optimizing the planning processes of seasonal thermal energy storage projects. UR - https://doi.org/10.1016/j.applthermaleng.2022.118810 KW - Seasonal Storage KW - Thermal Energy Storage KW - Component-based Modeling KW - Matlab / Simulink KW - Large-scale TES KW - Planning and Design Y1 - 2022 UR - https://doi.org/10.1016/j.applthermaleng.2022.118810 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-34926 SN - 1873-5606 VL - 2022 IS - 214 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Flach, Charley A1 - Conti, Fosca A1 - Bayraktar, Ahmet A1 - Goldbrunner, Markus T1 - Direct Methanation and Storage Concepts for the Flexibilization of Biogas Plants JF - Chemical Engineering & Technology N2 - Enrichment of the methane fraction in a biogas mixture is an innovative possibility to make existing biogas plants more flexible by using excess power. In the described concept, the CO2 in the biogas is directly catalytically converted into CH4 with H2. The CH4-enriched biogas is again fed into the digester to save energy for later use in the combined heat-and-power unit. Additionally, the fed heat gas can mix and heat the substrate. A heat pipe injector system was therefore developed for cooling the hot biogas stream after methanation and to prevent damage to the microbial consortia during the biomass mixing. The concept was proven at a laboratory-scale biogas plant. UR - https://doi.org/10.1002/ceat.202200239 KW - Biogas KW - Flexibilization KW - Injector KW - Methanation KW - Power to gas Y1 - 2022 UR - https://doi.org/10.1002/ceat.202200239 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-34914 SN - 1521-4125 VL - 46 IS - 3 SP - 579 EP - 586 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Tissen, Carolin A1 - Benz, Susanne A1 - Menberg, Kathrin A1 - Bayer, Peter A1 - Blum, Philipp T1 - Groundwater temperature anomalies in central Europe JF - Environmental Research Letters N2 - As groundwater is competitively used for drinking, irrigation, industrial and geothermal applications, the focus on elevated groundwater temperature (GWT) affecting the sustainable use of this resource increases. Hence, in this study GWT anomalies and their heat sources are identified. The anthropogenic heat intensity (AHI), defined as the difference between GWT at the well location and the median of surrounding rural background GWTs, is evaluated in over 10 000 wells in ten European countries. Wells within the upper three percentiles of the AHI are investigated for each of the three major land cover classes (natural, agricultural and artificial). Extreme GWTs ranging between 25 °C and 47 °C are attributed to natural hot springs. In contrast, AHIs from 3 to 10 K for both natural and agricultural surfaces are due to anthropogenic sources such as landfills, wastewater treatment plants or mining. Two-thirds of all anomalies beneath artificial surfaces have an AHI > 6 K and are related to underground car parks, heated basements and district heating systems. In some wells, the GWT exceeds current threshold values for open geothermal systems. Consequently, a holistic management of groundwater, addressing a multitude of different heat sources, is required to balance the conflict between groundwater quality for drinking and groundwater as an energy source or storage media for geothermal systems. UR - https://doi.org/10.1088/1748-9326/ab4240 KW - anthropogenic heat intensity (AHI) KW - CORINE land cover (CLC) KW - groundwater temperature (GWT) KW - temperature anomaly KW - central Europe Y1 - 2019 UR - https://doi.org/10.1088/1748-9326/ab4240 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-35794 SN - 1748-9326 VL - 14 IS - 10 PB - IOP Publishing CY - Bristol ER - TY - JOUR A1 - Bott, Christoph A1 - Dressel, Ingo A1 - Bayer, Peter T1 - Paraffin wax as self-sealing insulation material of seasonal sensible heat storage systems BT - A laboratory study JF - PLOS ONE N2 - Seasonal heat storage is considered as one of the key elements on the path to a low-emission economy. Embedded in local district heating networks, they raise the share of renewable energies and balance out highly fluctuating supplies of e.g. solar systems or windmills. The technology of seasonal heat storage can be described as almost technically mature, with well-established concepts and some systems being in operation for a considerable time. Nevertheless, the operating experience gained to date also revealed two critical problems. On the one hand, even smallest leakages in sealing foils led to irreparable breakdowns. On the other hand, heat loss in the marginal areas was revealed as a key deficiency, preventing the technology from advancing towards global marketability. This study presents an experimental approach to address these two key issues in the field of seasonal energy storage. Two small-scale laboratory tests were carried out to test paraffin wax as a completely novel component in the marginal area of seasonal storages. This is based on two material properties: As hydrophobic and mobile medium, the warmed and molten paraffin should actively seal the fissures and holes in the event of leakage. Additionally, the latent heat storage properties of the paraffin wax should increase the systems’ total storage capacity and reduce lateral heat losses via its low thermal conductivity. With retardation periods from 2.5 to 4 hours, the results show an effective phase change effect of the paraffin wax, which reduces energy losses and allows to buffer short-term, intensive loading and unloading processes. By storing up to 138 kJ/kg energy in the paraffin wax, increased capacities of application-scale pit storages by up to 40.70 MWh are to be expected. Additionally, the self-healing features could be successfully demonstrated: With only small losses of between 1.5 and 17%, the paraffin wax effectively sealed artificially incised leaks. Thereby, the mechanism was most effective for local defects. Following these positive demonstrations of feasibility, technical design questions still remain, which concern prevention of deformation of the paraffin wax. Once solved, this new component can then provide a path for further optimization of seasonal heat storage technologies. UR - https://doi.org/10.1371/journal.pone.0236056 Y1 - 2020 UR - https://doi.org/10.1371/journal.pone.0236056 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-34535 SN - 1932-6203 VL - 15 IS - 7 PB - PLOS CY - San Francisco ER - TY - JOUR A1 - Stöckl, Martin A1 - Idda, Johannes A1 - Selleneit, Volker A1 - Holzhammer, Uwe T1 - Flexible Operation to Reduce Greenhouse Gas Emissions along the Cold Chain for Chilling, Storage, and Transportation - A Case Study for Dairy Products JF - Sustainability N2 - The further expansion of renewable energies in Germany requires flexible consumers to balance fluctuations in electricity production from variable renewable energies. Cold storage warehouses, due to their inherent storage capacity and widespread use, are well-suited for integrating more renewable energies. The potential of cold storage warehouses is often viewed in isolation and not in conjunction with the cold chain’s upstream and downstream processes. By adjusting the temperatures within the processes, the individual links in the cold chain can be made flexible. To assess the effects of flexibilization on emissions and electricity costs, thermodynamic models of the individual links in the cold chain and of a yogurt pallet are developed and linked together. Due to temperature fluctuations in the products resulting from the flexibilization, emission evaluations must be considered throughout the cold chain. Results of the simulation for the study period show that emissions reductions and electricity cost savings can be achieved in all three links when they are made flexible. However, the savings vary in magnitude. Only minor savings can be achieved in the cooling tunnel. The greatest potential for savings is in refrigerated transport, if deeper cooling occurs in the process before, i.e., in the cold storage warehouse. UR - https://doi.org/10.3390/su152115555 KW - flexibility KW - flexible energy demand KW - system efficiency KW - cold storage warehouse KW - refrigerated transport KW - cold chain KW - variable renewable energies KW - industry KW - dairies Y1 - 2023 UR - https://doi.org/10.3390/su152115555 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-40844 SN - 2071-1050 VL - 15 IS - 21 PB - MDPI CY - Basel ER - TY - JOUR A1 - Mehta, Kedar A1 - Mingaleva, Ekaterina A1 - Zörner, Wilfried A1 - Degembaeva, Nadira A1 - Baibagyshov, Ermek T1 - Comprehensive analysis of the energy legislative framework of Kyrgyzstan BT - Investigation to develop a roadmap of Kyrgyz renewable energy sector JF - Cleaner Energy Systems N2 - Kyrgyzstan – a Central Asian country – faces a high degree of energy insecurity. Especially the Kyrgyz power sector suffers from outdated infrastructure and is not capable of fulfilling the growing and fluctuating inter-seasonal energy demand. On the contrary, the country is endowed with an abundant amount of renewable energies, which can significantly contribute to bringing stability to the energy sector. The current energy policy is considered as one of the key barriers to the developing the renewable energy sector in Kyrgyzstan. Hence, there is an immediate need to evaluate the formulated energy policy to investigate gaps and uncertainties. In response to that, the presented study is the first attempt that provides an in-depth assessment of Kyrgyzstan's current energy legislative framework. It determines the primary mechanisms for the operation and conduction of renewable energy sources in terms of legal and economic aspects. Furthermore, it provides detailed insight into the current Feed-in tariff calculation methodology and scrutinizes the special provisions for private investors. Based on the in-depth assessment, the article recapitulates the shortfall in the existing energy policies. The article found that there is huge potential available for the renewable energy market. To unlock that, the presented article emahsised on synergestic policy making approach to overcome barriers and expand the Kyrgyz renewable energy sector. The article further showcased how the improvements in the regulatory framework would raise the interest of the private investors / local energy players to promote the installation of renewable energy technologies over the county. UR - https://doi.org/10.1016/j.cles.2022.100013 KW - Central Asia KW - Energy policy KW - Energy legislation KW - Energy security KW - Kyrgyzstan KW - Renewable energies KW - Solar energy KW - Sustainable energy Y1 - 2022 UR - https://doi.org/10.1016/j.cles.2022.100013 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-29165 SN - 2772-7831 VL - 2022 IS - 2 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Towards Sustainable Community Development through Renewable Energies in Kyrgyzstan: A Detailed Assessment and Outlook JF - World N2 - In rural Kyrgyzstan, the energy need is usually derived from multiple natural energy resources such as firewood, charcoal, agricultural residues, animal dung, and wood branches, which are considered common and predominant practices. Because of the non-sustainable resources and heavy reliance on the environment, Kyrgyzstan is one of the most vulnerable countries to climate change in Central Asia. On the contrary, the great renewable energy potential in Kyrgyzstan is untapped, which could be the most promising solution to ensuring sustainable energy supply in the country. However, because of the lack of scientific knowledge, current energy policies, and the lack of infrastructure, renewable resources are mainly untapped. To exploit the country’s renewable energy potential, there is a need for a systematic diagnosis to develop a strategy to explore renewables in Kyrgyzstan, which is currently missing in the existing literature. In that regard, the presented study aims to assess the current status of renewable energy sources by considering the local energy context from a potential point of view. Further to this, it provides a comparative overview through a matrix of strengths, weaknesses, opportunities, and threats. Such novel analysis would be the fundamental base for formulating policy advice and a national plan to enhance the utilization of renewable energy in Kyrgyzstan. The presented analysis was carried out based on the extensive literature review, the country’s national plan, and the existing energy policies of Kyrgyzstan. The article found out that there is huge potential available for the renewable energy market. As compared to other renewable energy sources, solar energy has great potential and can be considered one of the pioneer sustainable sources for integration into the country’s power generation framework. UR - https://doi.org/10.3390/world3020018 KW - Central Asia KW - energy services KW - high-altitude KW - Kyrgyzstan KW - renewable energy resources KW - sustainable energy Y1 - 2022 UR - https://doi.org/10.3390/world3020018 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-28086 SN - 2673-4060 VL - 3 IS - 2 SP - 327 EP - 343 PB - MDPI CY - Basel ER - TY - JOUR A1 - Werner, Melanie A1 - Muschik, Sebastian A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Schrag, Tobias T1 - Sector Coupling Potential of A District Heating Network by Consideration of Residual Load and CO2 Emissions JF - Energies N2 - The growing share of fluctuating renewable electricity production within the German energy system causes the increasing necessity for flexible consumers, producers, and storage technologies to balance supply and demand. District heating networks with combined heat and power units, Power-to-Heat applications, and thermal energy storage capacities can serve as one of these flexible options. In this context, a simulation model of the district heating network of the rural community Dollnstein, Germany, was built. With the residual load of different regional areas (Germany, Bavaria, Eichstätt, Dollnstein) it is investigated, how the heat generators can operate in an electricity market beneficial way. Two different control algorithms were evaluated: Due to a correlation between the residual loads and the CO2 emissions of the electricity mix, the CO2 savings achieved by this control algorithm are determined. Another way to operate electricity market beneficial is to consider the current CO2 emissions of each region. The main outcomes of this paper are, that there is a high potential for sector coupling by shifting the operation times of a CHP and a heat pump according to the residual load. The electricity demand of the heat pump can be met in terms of low CO2 emissions of the electricity mix, while the CHP can replace electricity with high CO2 emissions. These results can be improved, by considering not the residual load but the current CO2 emissions in the control algorithm. UR - https://doi.org/10.3390/en15176281 KW - district heating networks KW - sector coupling KW - residual load KW - CO2 emissions Y1 - 2022 UR - https://doi.org/10.3390/en15176281 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-27820 SN - 1996-1073 VL - 15 IS - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Conti, Fosca A1 - Wiedemann, Leonhard A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - Effect of mixing of waste biomass in anaerobic digesters for production of biogas JF - IOP Conference Series: Materials Science and Engineering N2 - Biogas technology is an important renewable bioenergy producer. The biogas generating process needs to be optimized to minimise the energy consumption due to the stirring of biomass slurry. Numerical simulations and laboratory experiments are economically and practically preferred over investigations of industrial scale biogas plants. Additionally, a strategic approach to model the reality in scientific laboratories is to use a rheological valid artificial chemical substrate to replace real biomass. The proposes of this study were (i) to investigate the mixing process in a 1:12 scaled-down home-made laboratory digester filled with a 0.3 wt% water-cellulose solution, (ii) to simulate the mixing process in the laboratory-scale digester using a computational fluid dynamics model, (iii) to validate the model by comparison of the simulation with laboratory experiments results obtained on the laboratory digester. Optical and acoustic measurements on the flow velocity inside the digester during the mixing process of the water-cellulose solutions indicate that the model based on computational fluid dynamics is valid. The data are presented and discussed in the paper. UR - https://doi.org/10.1088/1757-899X/446/1/012011 Y1 - 2018 UR - https://doi.org/10.1088/1757-899X/446/1/012011 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-28021 SN - 1757-899X VL - 2018 IS - 446 PB - IOP Publishing CY - London ER - TY - JOUR A1 - Saidi, Abdessamad A1 - Conti, Fosca A1 - Sonnleitner, Matthias A1 - Goldbrunner, Markus T1 - Membrane separation process for small scaled partial biogas upgrading JF - IOP Conference Series: Materials Science and Engineering N2 - Biogas upgrading is actually limited to the production of biomethane as natural gas substitute. To realize the according gas quality a cost intensive methane enrichment is required, wherefore biogas upgrading is actually merely cost-efficient in case of high production rates. Since the energy and cost effort disproportionately increases with the required product gas purity partial biogas upgrading for decentralized utilization represents a promising utilization approach for farm based applications. Among the available technologies for CO2-separation the gas permeable membrane has high potential for small scaled biogas upgrading. Within the present study a model based analysis to determine the savings potential of a membrane based upgrading system is performed. UR - https://doi.org/10.1088/1757-899X/446/1/012012 Y1 - 2018 UR - https://doi.org/10.1088/1757-899X/446/1/012012 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-28012 SN - 1757-899X VL - 2018 IS - 446 PB - IOP Publishing CY - London ER - TY - JOUR A1 - Tissen, Carolin A1 - Menberg, Kathrin A1 - Bayer, Peter A1 - Blum, Philipp T1 - Meeting the demand BT - geothermal heat supply rates for an urban quarter in Germany JF - Geothermal Energy - Science, Society and Technology N2 - Thermal energy for space heating and for domestic hot water use represents about a third of the overall energy demand in Germany. An alternative to non-renewable energy-based heat supply is the implementation of closed and open shallow geothermal systems, such as horizontal ground source heat pump systems, vertical ground source heat pump (vGSHP) systems and groundwater heat pump systems. Based on existing regulations and local hydrogeological conditions, the optimal site-specific system for heat supply has to be identified. In the presented technical feasibility study, various analytical solutions are tested for an urban quarter before and after building refurbishment. Geothermal heat supply rates are evaluated by providing information on the optimal system and the specific shortcomings. Our results show that standard vGSHP systems are even applicable in older and non-refurbished residential areas with a high heat demand using a borehole heat exchanger with a length of 100 m or in conjunction with multiple boreholes. After refurbishment, all studied shallow geothermal systems are able to cover the lowered heat demand. The presented analysis also demonstrates that ideally, various technological variants of geothermal systems should be evaluated for finding the optimal solution for existing, refurbished and newly developed residential areas. UR - https://doi.org/10.1186/s40517-019-0125-8 KW - Ground source heat pump (GSHP) KW - Groundwater heat pump (GWHP) KW - Borehole heat exchanger (BHE) KW - Heat demand KW - Refurbishment KW - Geothermal potential KW - GIS Y1 - 2019 UR - https://doi.org/10.1186/s40517-019-0125-8 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-35833 SN - 2195-9706 VL - 7 PB - BioMed Central CY - London ER - TY - JOUR A1 - Ringel, Lisa Maria A1 - Somogyvári, Márk A1 - Jalali, Mohammadreza A1 - Bayer, Peter T1 - Comparison of Hydraulic and Tracer Tomography for Discrete Fracture Network Inversion JF - Geosciences N2 - Fractures serve as highly conductive preferential flow paths for fluids in rocks, which are difficult to exactly reconstruct in numerical models. Especially, in low-conductive rocks, fractures are often the only pathways for advection of solutes and heat. The presented study compares the results from hydraulic and tracer tomography applied to invert a theoretical discrete fracture network (DFN) that is based on data from synthetic cross-well testing. For hydraulic tomography, pressure pulses in various injection intervals are induced and the pressure responses in the monitoring intervals of a nearby observation well are recorded. For tracer tomography, a conservative tracer is injected in different well levels and the depth-dependent breakthrough of the tracer is monitored. A recently introduced transdimensional Bayesian inversion procedure is applied for both tomographical methods, which adjusts the fracture positions, orientations, and numbers based on given geometrical fracture statistics. The used Metropolis-Hastings-Green algorithm is refined by the simultaneous estimation of the measurement error’s variance, that is, the measurement noise. Based on the presented application to invert the two-dimensional cross-section between source and the receiver well, the hydraulic tomography reveals itself to be more suitable for reconstructing the original DFN. This is based on a probabilistic representation of the inverted results by means of fracture probabilities. UR - https://doi.org/10.3390/geosciences9060274 KW - hydraulic tomography KW - tracer tomography KW - DFN KW - Bayesian inversion KW - heterogeneity KW - fracture KW - hydrogeophysics Y1 - 2019 UR - https://doi.org/10.3390/geosciences9060274 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-35858 SN - 2076-3263 VL - 9 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Hemmerle, Hannes A1 - Hale, Sina A1 - Dressel, Ingo A1 - Benz, Susanne A1 - Attard, Guillaume A1 - Blum, Philipp A1 - Bayer, Peter T1 - Estimation of Groundwater Temperatures in Paris, France JF - Geofluids N2 - Subsurface temperature data is usually only accessible as point information with a very limited number of observations. To spatialize these isolated insights underground, we usually rely on interpolation methods. Unfortunately, these conventional tools are in many cases not suitable to be applied to areas with high local variability, like densely populated areas, and in addition are very vulnerable to uneven distributions of wells. Since thermal conditions of the surface and shallow subsurface are coupled, we can utilize this relationship to estimate shallow groundwater temperatures from satellite-derived land surface temperatures. Here, we propose an estimation approach that provides spatial groundwater temperature data and can be applied to natural, urban, and mixed environments. To achieve this, we combine land surface temperatures with anthropogenic and natural processes, such as downward heat transfer from buildings, insulation through snow coverage, and latent heat flux in the form of evapotranspiration. This is demonstrated for the city of Paris, where measurements from as early as 1977 reveal the existence of a substantial subsurface urban heat island (SUHI) with a maximum groundwater temperature anomaly of around 7 K. It is demonstrated that groundwater temperatures in Paris can be well predicted with a root mean squared error of below 1 K by means of satellite-derived land surface images. This combined approach is shown to improve existing estimation procedures that are focused either on rural or on urban conditions. While they do not detect local hotspots caused by small-scaled heat sources located underground (e.g., sewage systems and tunnels), the findings for the city of Paris for the estimation of large-scale thermal anomalies in the subsurface are promising. Thus, the new estimation procedure may also be suitable for other cities to obtain a more reliable insight into the spatial distribution of urban ground and groundwater temperatures. UR - https://doi.org/10.1155/2019/5246307 Y1 - 2019 UR - https://doi.org/10.1155/2019/5246307 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-35817 SN - 1468-8123 VL - 2019 PB - Hindawi CY - London ER - TY - JOUR A1 - Selleneit, Volker A1 - Stöckl, Martin A1 - Holzhammer, Uwe T1 - System efficiency: methodology for rating of industrial utilities in electricity grids with a high share of variable renewable energies BT - a first approach JF - Renewable and Sustainable Energy Reviews UR - https://doi.org/10.1016/j.rser.2020.109969 KW - system efficiency KW - industrial utilities KW - variable renewable energies KW - residual power KW - flexibility KW - electricity price time series Y1 - 2020 UR - https://doi.org/10.1016/j.rser.2020.109969 SN - 1364-0321 VL - 2020 IS - 130 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Selleneit, Volker A1 - Stöckl, Martin A1 - Philipp, Matthias A1 - Mast, Tanja A1 - Holzhammer, Uwe A1 - Schlosser, Florian T1 - System efficiency rating of industrial utilities in electricity grids with a high share of variable renewable energies JF - Chemical Engineering Transactions UR - https://doi.org/10.3303/CET1976163 Y1 - 2019 UR - https://doi.org/10.3303/CET1976163 SN - 2283-9216 VL - 2019 IS - 76 SP - 973 EP - 978 PB - AIDIC CY - Mailand ER - TY - JOUR A1 - Stöckl, Martin A1 - Selleneit, Volker A1 - Philipp, Matthias A1 - Holzhammer, Uwe T1 - An approach to calculate electricity costs for the german industry for a system efficient design by combining energy efficiency and demand response JF - Chemical Engineering Transactions UR - https://doi.org/10.3303/CET1976191 Y1 - 2019 UR - https://doi.org/10.3303/CET1976191 SN - 2283-9216 VL - 2019 IS - 76 SP - 1141 EP - 1146 PB - AIDIC CY - Mailand ER - TY - CHAP A1 - Hümmer, Benedikt A1 - Mast, Tanja A1 - Koller, Maria A1 - Holzhammer, Uwe T1 - Smart Markets in Southern Germany BT - key factors for profits of biogas plants T2 - 2020 17th International Conference on the European Energy Market (EEM) UR - https://doi.org/10.1109/EEM49802.2020.9221988 KW - biogas plants KW - market-based congestion management KW - Smart Market Y1 - 2020 UR - https://doi.org/10.1109/EEM49802.2020.9221988 SN - 978-1-7281-6919-4 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Mast, Tanja A1 - Hümmer, Benedikt A1 - Holzhammer, Uwe T1 - Potential of Demand Side Management and Biogas Plants in regional market-based Congestion Management T2 - ENERDAY 15th Conference on Energy Economics and Technology "Creative Destruction? Disruptive innovation in times of Covid and an accelerated energy system transformation": Book of Abstracts UR - https://tu-dresden.de/bu/wirtschaft/bwl/ee2/tagungen/enerday-archives KW - smart Market KW - grid congestion KW - biogas plants KW - demand side management Y1 - 2021 UR - https://tu-dresden.de/bu/wirtschaft/bwl/ee2/tagungen/enerday-archives SP - 22 EP - 23 PB - TU Dresden CY - Dresden ER - TY - CHAP A1 - Hümmer, Benedikt A1 - Mast, Tanja A1 - Holzhammer, Uwe ED - Nelles, Michael T1 - Einflussfaktoren auf das Erlöspotential von Biogasanlagen in Smart Markets T2 - Tagungsband 15. Rostocker Bioenergieforum UR - https://doi.org/10.18453/rosdok_id00003024 Y1 - 2021 UR - https://doi.org/10.18453/rosdok_id00003024 SN - 978-3-86009-524-9 SP - 109 EP - 118 PB - Universität Rostock CY - Rostock ER - TY - CHAP A1 - Mast, Tanja A1 - Nagel, Sylvio A1 - Holzhammer, Uwe A1 - Eltrop, Ludger T1 - Biogasanlagen neu denken BT - technisch-ökonomische Charakterisierung für die Einbindung in die modellgestützte Systemanalyse T2 - Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009-507-2 SP - 123 EP - 132 PB - Universität Rostock CY - Rostock ER - TY - JOUR A1 - Philipp, Matthias A1 - Schumm, Gregor A1 - Schlosser, Florian A1 - Peesel, Ron-Hendrick A1 - Holzhammer, Uwe T1 - Grundsatzfragen der Abwärmenutzung JF - BWK - Das Energie-Fachmagazin Y1 - 2017 UR - https://www.ingenieur.de/fachmedien/bwk/energieversorgung/grundsatzfragen-der-abwaermenutzung/ SN - 1618-193X VL - 69 IS - 4 SP - 36 EP - 39 PB - VDI Fachmedien CY - Düsseldorf ER - TY - CHAP A1 - Mast, Tanja A1 - Hümmer, Benedikt A1 - Holzhammer, Uwe T1 - Erlöspotential für Biogasanlagen an Smart Markets T2 - Tagungsunterlagen Zukünftige Stromnetze UR - https://www.zukunftsnetz.net/konferenz/tagungsbaende Y1 - 2021 UR - https://www.zukunftsnetz.net/konferenz/tagungsbaende SN - 978-3-948176-12-9 SP - 224 EP - 245 PB - Conexio GmbH CY - Pforzheim ER - TY - CHAP A1 - Dotzauer, Martin A1 - Büchner, Daniel A1 - Eltrop, Ludger A1 - Härdtlein, Marlies A1 - Henning, Christiane A1 - Herrmann, André A1 - Holzhammer, Uwe A1 - Kornatz, Peter A1 - Mast, Tanja A1 - Nagel, Sylvio A1 - Oehmichen, Katja A1 - Philipp, Matthias A1 - Pohl, Marcel A1 - Selleneit, Volker A1 - Thrän, Daniela ED - Thrän, Daniela ED - Pfeiffer, Diana T1 - Flexible Bereitstellung von Bioenergie T2 - Methodenhandbuch: Stoffstromorientierte Bilanzierung der Klimagaseffekte: Methoden zur Bestimmung von Technologiekennwerten, Gestehungskosten und Klimagaseffekten von Vorhaben im Rahmen des BMWi-Forschungsnetzwerkes Bioenergie/ BMWi-Förderbereich „Energetische Biomassenutzung“ UR - https://doi.org/10.48480/ddpt-ys74 Y1 - 2021 UR - https://doi.org/10.48480/ddpt-ys74 SN - 978-3-946629-58-0 SN - 2701-2719 SP - 56 EP - 108 PB - Deutsches Biomasseforschungszentrum gemeinnützige GmbH CY - Leipzig ET - Version 5 ER - TY - BOOK A1 - Eltrop, Ludger A1 - Nagel, Sylvio A1 - Holzhammer, Uwe A1 - Mast, Tanja A1 - Selleneit, Volker A1 - Tronnier, Annika A1 - Wachinger, Gisela ED - Eltrop, Ludger ED - Holzhammer, Uwe T1 - Methodenhandbuch "Bioenergie als Flexibilitätsoption im Energiesystem" T3 - Schriftenreihe "Energetische Biomassenutzung", Band 21 UR - https://doi.org/10.48480/m6ak-zr53 Y1 - 2021 UR - https://doi.org/10.48480/m6ak-zr53 SN - 2701-2719 PB - Deutsches Biomasseforschungszentrum gemeinnützige GmbH CY - Leipzig ER - TY - CHAP A1 - Mast, Tanja A1 - Holzhammer, Uwe A1 - Philipp, Matthias ED - Nelles, Michael T1 - SmartBio : Biogasanlagen als Akteur in neuen intelligenten, regionalen Märkten T2 - Tagungsband 12. Rostocker Bioenergieforum 2018 Y1 - 2018 UR - https://www.openagrar.de/receive/dimport_mods_00001878 SN - 978-3-86009-473-0 SP - 143 EP - 150 PB - Universität Rostock CY - Rostock ER - TY - CHAP A1 - Beringer, Jakob A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Zörner, Wilfried ED - Söllner, Matthias ED - Pirkl, Gerald T1 - Sustainable materials for insulating high-altitude rural Kyrgyz residential houses: A parametric economic study T2 - Applied Research Conference 2021, Conference Proceedings Y1 - 2021 UR - https://www.oth-aw.de/files/oth-aw/Aktuelles/Veroeffentlichungen/Applied_Research_Conference_ARC2021_Proceedings.pdf SP - 183 EP - 188 PB - Ostbayerische Technische Hochschule Amberg-Weiden CY - Amberg ER - TY - CHAP A1 - Knepper, Karoline A1 - Ehrenwirth, Mathias A1 - Zörner, Wilfried ED - Söllner, Matthias ED - Pirkl, Gerald T1 - Potential of e- mobility in rural areas – Evaluation of opportunities and barriers based on literature review T2 - Applied Research Conference 2021, Conference Proceedings Y1 - 2021 UR - https://www.oth-aw.de/files/oth-aw/Aktuelles/Veroeffentlichungen/Applied_Research_Conference_ARC2021_Proceedings.pdf SP - 216 EP - 220 PB - Ostbayerische Technische Hochschule Amberg-Weiden CY - Amberg ER - TY - CHAP A1 - Wageneder, Stefanie A1 - Grösch, Norbert A1 - Saidi, Abdessamad A1 - Wagner, Robert A1 - Glötzl, Melanie A1 - Gleich, Jasmin A1 - Hermann, Christiane A1 - Mielke, Sophie A1 - Freydank, Christian A1 - Zörner, Wilfried T1 - Lösungsansätze zur technischen Anpassung bestehender Biogasanlagen für die Nutzung faseriger Reststoffe BT - Auswahl der zu untersuchenden Anlagen im Rahmen des Projekts „LaRA“ T2 - Schriftenreihe Umweltingenieurwesen Agrar- und Umweltwissenschaftliche Fakultät, Band 95, Tagungsband 14. Rostocker Bioenergieforum / 19. DIALOG Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009-507-2 SP - 409 EP - 414 PB - Universität Rostock, Agrar- und Umweltwissenschaftliche Fakultät CY - Rostock ER - TY - CHAP A1 - Bugaje, Aminu A1 - Yadav, Akhilesh A1 - Mehta, Kedar A1 - Ojinji, Felicia A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Influence of input parameters on artificial neural networks for off-grid solar photovoltaic power forecasting T2 - NEIS 2021 KW - solar power forecast KW - off-grid solar system KW - artificial neural networks KW - mean squared error KW - correlation coefficient KW - mean absolute error Y1 - 2021 UR - https://ieeexplore.ieee.org/document/9698257 UR - https://www.vde-verlag.de/proceedings-en/565651017.html SN - 978-3-8007-5651-3 SN - 978-3-8007-5652-0 SP - 135 EP - 141 PB - VDE Verlag CY - Berlin ER - TY - CHAP A1 - Bugaje, Aminu A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Bär, Katharina A1 - Zörner, Wilfried ED - Schulz, Detlef T1 - Development of a load management algorithm using nonlinear programming (NLP) for optimum integration of electric-mobility solutions into rural off-grid PV systems T2 - NEIS 2020 KW - load management KW - NLP KW - CARNOT KW - electric mobility KW - off-grid KW - PV systems KW - objective function Y1 - 2020 UR - https://ieeexplore.ieee.org/document/9273412 UR - https://www.vde-verlag.de/proceedings-en/565359022.html SN - 978-3-8007-5359-8 SN - 978-3-8007-5360-4 N1 - Auch veröffentlicht auf IEEE: https://ieeexplore.ieee.org/document/9273412 SP - 167 EP - 172 PB - VDE Verlag CY - Berlin ER - TY - CHAP A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - A parametric study on the feasibility of solar-thermal space heating and hot water preparation under cold climates in Central Asian rural areas T2 - EuroSun 2020 Proceedings UR - https://dx.doi.org/10.18086/eurosun.2020.04.03 KW - cold climate KW - building KW - solar-thermal energy KW - space heating KW - domestic hot water Y1 - 2020 UR - https://dx.doi.org/10.18086/eurosun.2020.04.03 PB - International Solar Energy Society CY - Freiburg ER - TY - CHAP A1 - Grösch, Norbert A1 - Vogt, Regine A1 - Saidi, Abdessamad A1 - Zörner, Wilfried T1 - Repoweringmaßnahmen hinsichtlich zukünftiger Aufgaben von Biogasanlagen BT - Ergebnisse aus dem Projekt REzAB T2 - Schriftenreihe Umweltingenieurwesen Agrar- und Umweltwissenschaftliche Fakultät, Band 95, Tagungsband 14. Rostocker Bioenergieforum / 19. DIALOG Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 KW - Biogas KW - Repowering KW - Konzepte KW - Bestandsanlagen KW - Weiterbetrieb Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009-507-2 SP - 133 EP - 142 PB - Universität Rostock, Agrar- und Umweltwissenschaftliche Fakultät CY - Rostock ER - TY - CHAP A1 - Stark, Matthias A1 - Saidi, Abdessamad A1 - Zörner, Wilfried T1 - KomBio-Speicher BT - Entwicklung eines neuartigen Dampfspeichersystems für ein flexibles Biomasse-Heizkraftwerk zur Erhöhung der Systemstabilität T2 - Schriftenreihe Umweltingenieurwesen Agrar- und Umweltwissenschaftliche Fakultät, Band 95, Tagungsband 14. Rostocker Bioenergieforum / 19. DIALOG Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009-507-2 SP - 345 EP - 354 PB - Universität Rostock, Agrar- und Umweltwissenschaftliche Fakultät CY - Rostock ER - TY - CHAP A1 - Riedmaier, Thomas A1 - Bär, Katharina A1 - Zörner, Wilfried ED - Söllner, Matthias ED - Pirkl, Gerald T1 - Comparison of different calculation methods for the outflow from pressurized vessels T2 - Applied Research Conference 2021, Conference Proceedings Y1 - 2021 UR - https://www.oth-aw.de/files/oth-aw/Aktuelles/Veroeffentlichungen/Applied_Research_Conference_ARC2021_Proceedings.pdf SP - 258 EP - 263 PB - Ostbayerische Technische Hochschule Amberg-Weiden CY - Amberg ER - TY - CHAP A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Impact of locally available thermal insulation structures on space heating demand of high-altitude rural buildings BT - a case study of Kyrgyzstan T2 - EuroSun 2020 Proceedings UR - https://dx.doi.org/10.18086/eurosun.2020.04.04 KW - domestic space heating KW - energy efficiency KW - cold climate KW - high-altitude KW - thermal insulation Y1 - 2020 UR - https://dx.doi.org/10.18086/eurosun.2020.04.04 PB - International Solar Energy Society CY - Freiburg ER - TY - JOUR A1 - Stark, Matthias A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Steam storage systems for flexible biomass CHP plants BT - evaluation and initial model based calculation JF - Biomass and Bioenergy UR - https://doi.org/10.1016/j.biombioe.2019.105321 KW - CHP KW - solid biomass KW - steam storage KW - high temperature storage KW - flexible power generation Y1 - 2019 UR - https://doi.org/10.1016/j.biombioe.2019.105321 SN - 0961-9534 VL - 2019 IS - 128 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Yadav, Akhilesh A1 - Sinha, Anuj A1 - Saidi, Abdessamad A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - NILM based energy disaggregation algorithm for dairy farms T2 - NILM'20: Proceedings of the 5th International Workshop on Non-Intrusive Load Monitoring UR - https://doi.org/10.1145/3427771.3427846 KW - NILM KW - energy disaggregation KW - smart meter KW - dairy farms KW - deep neural networks Y1 - 2020 UR - https://doi.org/10.1145/3427771.3427846 SN - 978-1-4503-8191-8 SP - 16 EP - 19 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Stark, Matthias A1 - Philipp, Matthias A1 - Saidi, Abdessamad A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Design parameters of steam accumulators for the utilization in industrial solid biomass-fuelled CHP plants JF - Chemical Engineering Transactions UR - https://doi.org/10.3303/CET1976137 Y1 - 2019 UR - https://doi.org/10.3303/CET1976137 SN - 978-88-95608-73-0 SN - 2283-9216 VL - 2019 IS - 76 SP - 817 EP - 822 PB - AIDIC The Italian Association of Chemical Engineering CY - Milano ER - TY - JOUR A1 - Bär, Katharina A1 - Saidi, Abdessamad A1 - Hackl, Christoph A1 - Zörner, Wilfried T1 - Combined operation of photovoltaic and biogas plants for optimal transformer loading JF - Chemical Engineering Transactions UR - https://doi.org/10.3303/CET1976101 Y1 - 2019 UR - https://doi.org/10.3303/CET1976101 SN - 978-88-95608-73-0 SN - 2283-9216 VL - 2019 IS - 76 SP - 601 EP - 606 PB - AIDIC The Italian Association of Chemical Engineering CY - Milano ER - TY - CHAP A1 - Vannahme, Anna A1 - Ramm, Tobias A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias ED - Haumer, Anton T1 - Comparison of a usual heat-transfer-station with a hydraulic modified version under the aspect of exergy saving T2 - Proceedings of the 13th International Modelica Conference UR - http://dx.doi.org/10.3384/ecp19157647 KW - heat-transfer-station KW - hydraulic system KW - control design KW - district heating KW - single-family house Y1 - 2019 UR - http://dx.doi.org/10.3384/ecp19157647 SN - 978-91-7685-122-7 SN - 1650-3686 SN - 1650-3740 SP - 647 EP - 654 PB - Linköping University Electronic Press CY - Linköping ER - TY - CHAP A1 - Schrag, Tobias A1 - Ehrenwirth, Mathias A1 - Ramm, Tobias A1 - Vannahme, Anna A1 - Trinkl, Christoph ED - Belasri, Ahmed ED - Beldjilali, Sid Ahmed T1 - Solar energy use in district heating networks T2 - ICREEC 2019: Proceedings of the 1st International Conference on Renewable Energy and Energy Conversion UR - https://doi.org/10.1007/978-981-15-5444-5_1 KW - district heating systems KW - solar energy KW - heat pumps Y1 - 2020 UR - https://doi.org/10.1007/978-981-15-5444-5_1 SN - 978-981-15-5443-8 SN - 978-981-15-5446-9 SN - 978-981-15-5444-5 SN - 2352-2534 SN - 2352-2542 N1 - Access provided by Nationallizenz Ebooks Medicine SP - 3 EP - 10 PB - Springer CY - Singapur ER - TY - CHAP A1 - Lauermann, Magdalena A1 - Betz, Florian A1 - Mehta, Kedar A1 - Thevs, Niels A1 - Ehrenwirth, Mathias A1 - Zörner, Wilfried A1 - Cyffka, Bernd T1 - Preservation of Selected Ecosystem Services in the Floodplains of the Naryn River (Kyrgyzstan): Introducing the ÖkoFlussPlan Project T2 - Beiträge zum 50. und 51. Jahrestreffen des Arbeitskreises Hydrologie 2018 in Koblenz und 2019 in Heidelberg Y1 - 2020 UR - https://www.uni-augsburg.de/de/fakultaet/fai/geo/forschung/geographicaaugustana/ SP - 47 EP - 53 PB - Institut für Geographie, Universität Augsburg CY - Augsburg ER - TY - CHAP A1 - Ramm, Tobias A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias ED - Haumer, Anton T1 - Modelling of the central heating station within a district heating system with variable temperatures T2 - Proceedings of the 13th International Modelica Conference UR - http://dx.doi.org/10.3384/ecp19157567 KW - district heating system KW - model KW - Modelica KW - variable temperature KW - validation Y1 - 2019 UR - http://dx.doi.org/10.3384/ecp19157567 SN - 978-91-7685-122-7 SN - 1650-3686 SN - 1650-3740 SP - 567 EP - 576 PB - Modelica Association and Linköping University Electronic Press CY - Linköping ER - TY - JOUR A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Hanby, Victor Ian T1 - Simulation study on a domestic solar/heat pump heating system incorporating latent and stratified thermal storage JF - Journal of Solar Energy Engineering UR - https://doi.org/10.1115/1.3197845 KW - heat pumps KW - solar absorber-convertors KW - solar heating KW - thermal energy storage Y1 - 2009 UR - https://doi.org/10.1115/1.3197845 SN - 1528-8986 SN - 0199-6231 VL - 131 IS - 4 PB - ASME CY - New York ER - TY - JOUR A1 - Hasler, Ewald A1 - Huber, Christian A1 - Leindecker, Herbert C. A1 - Schrag, Tobias A1 - Stocker, Emanuel A1 - Wartha, Christian T1 - Bewertung unterschiedlicher Fassadenkonstruktionen unter Lebenszyklusaspekten mit einer Fallstudie Bürogebäude JF - Bauphysik UR - https://doi.org/10.1002/bapi.201310072 Y1 - 2013 UR - https://doi.org/10.1002/bapi.201310072 SN - 1437-0980 VL - 35 IS - 4 SP - 250 EP - 256 PB - Ernst & Sohn CY - Berlin ER - TY - CHAP A1 - Saidi, Abdessamad A1 - Conti, Fosca A1 - Karl, Jürgen A1 - Goldbrunner, Markus ED - Thrän, Daniela ED - Pfeiffer, Diana T1 - Biogastankstelle für die Landwirtschaft – Gegenüberstellende ökonomische Bewertung unterschiedlicher Verfahren für die dezentrale partielle Biogasaufbereitung T2 - 8. Statuskonferenz Bioenergie Reader Y1 - 2019 UR - https://www.energetische-biomassenutzung.de/veranstaltungen/statuskonferenzen/8-statuskonferenz/programm SN - 978-3-946629-27-6 SN - 2698-6809 SP - 78 EP - 79 PB - DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH CY - Leipzig ER - TY - CHAP A1 - Conti, Fosca A1 - Wiedemann, Leonhard A1 - Saidi, Abdessamad A1 - Sonnleitner, Matthias A1 - Goldbrunner, Markus T1 - Mixing of a Model Substrate in a Scale-down Laboratory Digester and Processing with a Computational Fluid Dynamics Model T2 - EUBCE 2018 Online Conference Proceedings UR - https://doi.org/10.5071/26thEUBCE2018-2CV.5.34 KW - anaerobic digestion KW - biomass KW - cellulose KW - laboratory digester KW - mixing process KW - fluid dynamic Y1 - 2018 UR - https://doi.org/10.5071/26thEUBCE2018-2CV.5.34 SN - 978-88-89407-18-9 SN - 2282-5819 SP - 811 EP - 815 PB - ETA s.r.l. CY - Florenz ER - TY - CHAP A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus ED - Thrän, Daniela ED - Pfeiffer, Diana T1 - Verbesserung der Durchmischung in Biogasfermentern T2 - 8. 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UR - doi.org/10.37544/1618-193X-2022-7-8 KW - Energiesystemmodellierung KW - Elektromobilität KW - Energiebedarf KW - Leistungsbedarf Y1 - 2022 UR - doi.org/10.37544/1618-193X-2022-7-8 SN - 1618-193X VL - 74 IS - 7-8 SP - 44 EP - 48 PB - VDI fachmedien CY - Düsseldorf ER - TY - JOUR A1 - Stark, Matthias A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Methodological Evaluation of Storage Systems for Flexible Power Generation from Solid Biomass JF - Chemical Engineering & Technology UR - https://doi.org/10.1002/ceat.201800099 KW - biomass combustion plan KW - delphi survey KW - flexible power generation KW - solid biomass KW - steam storage Y1 - 2018 UR - https://doi.org/10.1002/ceat.201800099 SN - 1521-4125 N1 - Part of Special Issue "Bioenergy – Flexible and Integrated Into the Next Age" VL - 41 IS - 11 SP - 2168 EP - 2176 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Zörner, Wilfried A1 - Mahomed, Nawaz A1 - Zulu, Ackim A1 - Bader, Tobias A1 - Tenthani, Chifundo A1 - Cuamba, Boaventura A1 - Chingosho, Hilton T1 - Meta-profile and competencies for harmonisation of higher education in sector-specific technology areas BT - A case study of Renewable Energy in Southern Africa JF - Tuning Journal for Higher Education Y1 - 2020 SN - 2386-3137 VL - 8 IS - 1 SP - 75 EP - 97 PB - University of Deusto CY - Bilbao ER - TY - JOUR A1 - Pophillat, William A1 - Attard, Guillaume A1 - Bayer, Peter A1 - Hecht-Méndez, Jozsef A1 - Blum, Philipp T1 - Analytical solutions for predicting thermal plumes of groundwater heat pump systems JF - Renewable Energy UR - https://doi.org/10.1016/j.renene.2018.07.148 Y1 - 2018 UR - https://doi.org/10.1016/j.renene.2018.07.148 SN - 1879-0682 VL - 2020 IS - 147, Part 2 SP - 2696 EP - 2707 PB - Elsevier CY - Amsterdam ER -