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 - 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 - Saidi, Abdessamad A1 - Trinkl, Christoph A1 - Conti, Fosca A1 - Goldbrunner, Markus A1 - Karl, Jürgen T1 - Partially Upgraded Biogas: Potential forDecentralized Utilization in AgriculturalMachinery JF - Chemical Engineering & Technology UR - https://doi.org/10.1002/ceat.201800100 KW - Agriculture KW - Biogas KW - Combustion KW - Fuel KW - Upgrading Y1 - 2018 UR - https://doi.org/10.1002/ceat.201800100 SN - 1521-4125 VL - 41 IS - 11 SP - 2111 EP - 2119 PB - Wiley-VCH CY - Weinheim 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 - 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 - 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 - CHAP A1 - Schmitt, David A1 - Reum, Tobias A1 - Summ, Thorsten A1 - Trinkl, Christoph A1 - Schrag, Tobias ED - Droege, Peter ED - Quint, Lelia T1 - Potential of a Long-Term Predictive Controller for Managing Energy Storages to Reduce the Electric Grid-Load of an Air-Source Heat Pump T2 - Proceedings of the International Renewable Energy Storage and Systems Conference (IRES 2023) N2 - Electrifying the domestic heating sector is mandatory to decarbonize the buildings sector but leads to additional peak loads in the public grid. Air-source heat pumps the mostly used technology in this regard even though, they suffer from lower efficiency during times of high heat demands. The usage of energy storages and predictive controllers enables operation shifting and hence offers potential to decrease the peak loads in the electric grid. This potential can be increased by using a longer prediction horizon as extended operation shifting can be performed. In this contribution, a methodology to derive the theoretical potential on the grid peak load reduction of such a long-term predictive controller is introduced. The electric load profile of an air-source heat pump in a typical German single-family home was generated based on different weather data scenarios for the city of Ingolstadt. Based on the profile the dependency between peak load reduction and required storage capacity was identified. In the case study a reduction of the peak load from 21 – 31% for an unrenovated building was achieved using a 500 L buffer storage. Further investigation needs to be done to derive a more realistic potential for renovated or new buildings. UR - https://doi.org/10.2991/978-94-6463-455-6_21 Y1 - 2024 UR - https://doi.org/10.2991/978-94-6463-455-6_21 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-49963 SN - 978-94-6463-455-6 SP - 205 EP - 211 PB - Atlantis Press CY - Dordrecht 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 - Summ, Thorsten A1 - Oyinlola, Muyiwa A1 - Khattak, Sanober A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Towards maximum cost-effectiveness: multi-objective design optimisation of insulating glass flat-plate collectors JF - Applied Thermal Engineering N2 - A significant challenge in the advancement of solar thermal heating systems lies in the unexplored techno-economic potential of insulating glass flat-plate collectors. These collectors are constructed in accordance with the specifications of standard insulating glass units and have emerged over the past decade as a promising design concept for enhancing the cost-effectiveness of solar thermal systems. However, substantial findings regarding the techno-economic viability of their production are still pending. The aim of this paper is to optimise insulating glass collector designs for solar district heating applications by identifying key design parameters that maximise cost-effectiveness. This study employed a five-stage methodology. It included thermo-hydraulic collector modelling using MATLAB/Simscape and the CARNOT Toolbox. The model was validated against experimental performance tests. A Latin hypercube computational design with 250,000 samples was set up to train supervised machine learning metamodels and perform a multi-objective optimisation using an elitist genetic algorithm. The study identified the argon concentration, collector length, and width as critical parameters influencing efficiency. Larger, thinner collectors demonstrated superior performance due to reduced convective losses and increased aperture-to-surface ratios. The optimisation revealed that the insulating glass collectors could achieve a 7.7 percentage point increase in efficiency, a 19.4 % reduction in material cost, and a 14.5 % decrease in weight compared to market-available flat-plate collectors. However, the direct economic comparison was not considered strong in evidence due to a lack of economic data from technology providers. The most cost-effective designs featured an argon concentration of 99 %, sealing thickness of 31.2 mm, and a glazing thickness of 4.1 mm, and 4.5 mm, while collector length and width varied more significantly. The research findings indicate the techno-economic potential of insulating glass collectors, demonstrating their ability to outperform conventional flat-plate collectors in terms of cost-effectiveness and efficiency. Future studies should focus on producing and testing larger modules and incorporating production costs to fully realise their potential for solar district heating applications. This study provides valuable guidelines for IGU designers and producers aiming to develop cost-effective and efficient solar thermal collectors for district heating systems. UR - https://doi.org/10.1016/j.applthermaleng.2024.124594 Y1 - 2024 UR - https://doi.org/10.1016/j.applthermaleng.2024.124594 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-53618 SN - 1359-4311 VL - 2025 IS - 258 PB - Elsevier CY - Amsterdam 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 - Vannahme, Anna A1 - Patel, Dharmik A1 - Schmitt, David A1 - Summ, Thorsten A1 - Trinkl, Christoph A1 - Schrag, Tobias T1 - Technical and economic analysis of digitally controlled substations in local district heating networks JF - Energy N2 - Since the 1990s, there has been a noticeable increase in the establishment of local district heating networks in Germany, coinciding with the use of thermal energy from biogas and biomass facilities. Historically, the prioritization of economically efficient heat utilization was subdued due to favorable electricity feed-in tariffs. However, with the expiration of Renewable Energy Sources Act subsidies, operators shifted focus to the operational costs of district heating networks. This study aims to examine the effects of optimizing controllers and valves at district heating substations in single-family homes, utilizing two local district heating networks. The emphasis is on evaluating impacts on operating costs and determining whether the economic and energetic benefits justify implementation. Simulation studies in MATLAB/Simulink Simscape depict both consumers and district heating networks individually, without aggregation. In the most favorable scenario, investing in enhancing substation controllers in single-family homes is projected to yield returns after 13 years. Comprehensive optimization of all substation controls in single-family homes can potentially result in up to 9% savings in thermal energy demand due to reduced heat losses and a corresponding 9% reduction in electrical power consumption for the main pump. UR - https://doi.org/10.1016/j.energy.2024.133585 Y1 - 2024 UR - https://doi.org/10.1016/j.energy.2024.133585 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-52718 SN - 0360-5442 SN - 1873-6785 VL - 2024 IS - 312 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Häring, Georg A1 - Trinkl, Christoph A1 - Zörner, Wilfried ED - Der Präsident der Hochschule für angewandte Wissenschaften FH Ingolstadt, T1 - Messtechnische Analyse der Grundwasserwärmepumpenanlage in einem Büro- und Produktionsgebäude N2 - In einer messtechnischen Untersuchung wurde vom KOMPETENZFELD ERNEUERBARE ENERGIEN die Leistungsfähigkeit eines grundwassergespeisten Heiz- und Kühlsystems mit Wärmepumpen in einem Büro- und Produktionsgebäude analysiert und bewertet. Dazu wurde eine umfängliche energetische Bilanzierung von Gebäudetechnik und Gebäude vorgenommen. Innerhalb des mehrjährigen Untersuchungszeitraumes konnten umfangreiche Erkenntnisse über die Effizienz und Arbeitsweise der Heiz- und Kühlanlage gewonnen werden. Dabei wurden eine Reihe von Problemstellungen im realen Anlagenbetrieb identifiziert sowie das Gesamtsystem auf Basis der Messergebnisse optimiert. Um die praxisrelevanten Forschungsergebnisse in zukünftigen innovativen Gebäudetechnikkonzepten einfließen zu lassen wurden konkrete Handlungsempfehlungen für die Planungs-, die Inbetriebnahme- und Einregulierungsphase sowie für die Betriebsführung abgeleitet. T3 - Arbeitsberichte - Working Papers - 21 KW - Wärmepumpe Y1 - 2011 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-373 SN - 1612-6483 PB - Technische Hochschule Ingolstadt CY - Ingolstadt ER -