TY - RPRT A1 - Reiter, Christoph A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Kunststoffe in solarthermischen Kollektoren - Anforderungsdefinition, Konzeptentwicklung und Machbarkeitsbewertung BT - Abschlussbericht im Forschungsvorhaben Solarthermie2000plus N2 - Die Hersteller von Solarwärmeanlagen bemühen sich stetig um die Senkung der Herstellkosten, vor allem des Solarkollektors, des weithin sichtbaren „Herzstücks“ jeder Solarwärmeanlage. Massiv steigende Weltmarktpreise für die hauptsächlich eingesetzten Werkstoffe Aluminium und Kupfer laufen den Bemühungen nach weiteren Kostensenkungen in der Kollektorfertigung aber leider entgegen. Der Einsatz von alternativen Werkstoffen, wie etwa Kunststoffen, für Solarkollektoren wird daher als vielversprechend angesehen. Die Verwendung von Kunststoffen im Solarkollektorbau kann dabei gleich mehrere Vorzüge bieten. Neben der Einsparung von kostspieligem Kupfer und/oder Aluminium sind mit den polymeren Materialien durch eine mögliche Gewichtsreduzierung gleichzeitig auch Vorteile bei der Montage verbunden. Durch Nutzung moderner Fertigungstechnologien von Kunststoffformteilen kann zudem die Kollektorfertigung automatisiert und damit die Kosten weiter gesenkt werden. Allerdings sind mit dem Einsatz von Kunststoffen bei den thermisch oft hoch belasteten Solarkollektoren auch technologische Herausforderungen verbunden. So stellen beispielsweise die begrenzte Temperatur-, Druck-, UV- und Langzeitbeständigkeit sowie die gegenüber Kupfer schlechtere Wärmeleitfähigkeit kostengünstiger Kunststoffe hohe Hürden für deren Einsatz in Solarkollektoren dar. Im Rahmen des Forschungsvorhabens wurden zunächst die auftretenden Temperaturlasten an den Kollektorbauteilen im Feldtest im Detail erfasst und in Jahreshistogrammen analysiert. Dabei erreicht der im System eingebundene Absorber Temperaturen von bis zu 192°C. Ein dauerhaft stagnierender Referenzabsorber erreicht 208°C und verweilt über 1.100 Stunden im Jahr auf einem Temperaturniveau von mehr als 95°C. Dies verdeutlicht die Notwendigkeit einer Reduktion oder im besten Fall einer aktiven Kontrolle der auftretenden Temperaturbelastungen an einigen Bauteilen, wie etwa dem Absorber. Desweiteren wird aber auch deutlich, dass für sämtliche Gehäusebauteile die Temperaturbelastung nicht die zentrale Hürde für den Kunststoffeinsatz darstellt. Zusammenfassend zeigt sich in den Messungen, dass im Hinblick auf Werkstoffspezifikationen eine sehr diversifizierte Betrachtung der Temperaturverläufe auf Bauteilebene erforderlich ist, anstelle der Angabe einer einheitlichen Maximaltemperatur für den gesamten Kollektor. Anschließend wurden sowohl verfügbare als auch potenzielle Überhitzungsschutzmaßnahmen für solarthermische Kollektoren erfasst und hinsichtlich ihrer Wirkmechanismen systematisiert. Ausgewählte Maßnahmen wurden in einer Simulation unter Nutzung eines speziell entwickelten, dynamischen Kollektormodells auf ihr Einsatzpotenzial hin untersucht. Es zeigt sich. dass eine nennenswerte Reduktion der thermischen Belastung an den Kollektorbauteilen u.a. ohne Einbuße des Anlagenertrages mit verschiedenen Maßnahmen prinzipiell durchaus erreichbar ist und vor allem perspektivisch erreicht werden kann. Das bedeutet, es werden Lösungswege aufgezeigt um den Einsatz neuer Werkstoffe wie etwa kostengünstiger Massenkunststoffe sogar am Absorber, also dem aus Sicht der Temperaturbelastung kritischsten Bauteil, realisieren zu können. Die dargestellten Simulationsergebnisse zeigen darüber hinaus einerseits die Zielparameter für die zweifelsfrei noch erforderliche Entwicklung, andererseits aber auch das Anwendungspotenzial einzelner Lösungen wie etwa den thermochromen Schichten auf, das in der Zukunft in jedem Fall zu heben ist. Auf Basis dieser Ergebnisse wurden Konzepte für Kunststoffkollektoren unter Nutzung adäquater Fertigungsverfahren entwickelt, um die Umsetzungs- und Gestaltungsmöglichkeiten aufzuzeigen. Abschließend wurden diese Konzepte hinsichtlich der Herstellkosten mit Standard-Flachkollektoren verglichen, wobei Kunststoffkollektoren neben den Vorteilen bei der Montage und Installation ein Kostensenkungspotenzial von bis zu 50% Prozent aufweisen können. KW - Solarthermie Y1 - 2011 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-49 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 - 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 - 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 - RPRT A1 - Häring, Georg A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Regeneratives Heizen und Kühlen in einem Multifunktionsgebäude: Überwachung und Bewertung einer regenerativ versorgten Heiz und Kühlanlage in einem Multifunktionsgebäude BT - Abschlussbericht im Demonstrationsvorhaben KW - Wärmepumpe KW - Photovoltaik Y1 - 2010 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-3609 ER - TY - RPRT A1 - Haller, Achim A1 - Trinkl, Christoph A1 - Wittmann, Roland A1 - Zörner, Wilfried T1 - Nutzung thermischer Solarenergie zur sorptionsgestützten Klimatisierung: Planung, Errichtung und Überwachung einer solargestützten Gebäudeklimatisierung in einer gewerblich genutzten Halle BT - Demonstrationsvorhaben ; Abschlussbericht N2 - The CENTRE OF EXCELLENCE FOR SOLAR ENGINEERING of Ingolstadt University of Applied Sciences investigates the renewable-only based HVAC system of a multipurpose building. The 10.000 m² gross floor area building is part of the biggest logistic-centre in the region serving the AUDI automobile production facilities. On the one hand, the investigation is supposed to demonstrate the potential of solar-assisted cooling, on the other hand, the monitoring focuses on the total energy balance of the building and the various innovative building technologies. Next to a ground source heat pump plant for base-load heating and cooling, the building is equipped with two arrays of solar-thermal flat-plate collectors (108 m² + 178 m²) and a desiccant air-conditioning system (DEC). This consists of two plants with a nominal air flow of 8.000 m³/h each. One of the two plants is monitored, where the plant itself is considered a black box in a first approach, i.e. all incoming and outgoing energy flows and the air condition are measured. Apart from the investigation of the performance of the solar-assisted air-conditioning system, the feasibility of DECoperation using flat-plate collectors available on the market is investigated. During the first year of operation (2006) massive problems occurred in the operation of the DEC-plant. While the degree of comfort in the building was found to be satisfying during the cooling period, the solar-driven DEC-plant showed major deficiencies in cooling performance, hydraulics and control. Especially, a too high rotational speed of the desiccant wheel and an inadequate adjustment of solar collector arrays, DEC-plants and building structure were identified. Therefore, in an overhaul of the system several problems in the hardware were found and corrected such as blocked nozzles due to calcinations, leakages in the sealing of the desiccant wheel and an incorrect installation of a non-return valve in the hydraulic system of the regeneration air heater. Moreover, the control strategy regarding the cooling power of the plant and the speed of the desiccant wheel was checked. In the second year of operation (2007), some deficiencies of the first year were found to be removed, but the plant still did not work according to its capacity. Insufficient dehumidification by the desiccant wheel was identified as a major problem. Based on a detailed analysis of the desiccant wheel, one-sided displacement of the sorbent was supposed to be the reason for insufficient cooling capacity. Obviously, control or mechanical malfunctions during operation have lead to a one-sided oversaturation and thus to a one-sided damage of the desiccant wheel. Consequently, the damaged wheel is to be removed prior to the 2008 cooling period. In order to tap the full potential of both the solar DEC-plant and the building’s innovative concept, a number of further measures, especially concerning the matching of the DECplant and the solar system with the building management, need to be taken in future. KW - Klimatechnik KW - Thermische Solaranlage Y1 - 2008 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-3613 ER - TY - RPRT A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - Planung, Errichtung, Betrieb und Optimierung einer solarunterstützten Gebäudeheizung in einem Altbau BT - Demonstrationsvorhaben Rationelle Energienutzung / Erneuerbare Energien ; Abschlussbericht N2 - Vor dem Hintergrund der weiteren Verbreitung solarunterstützter Heizungsanlagen auch im Gebäudebestand und der damit oftmals verbundenen Frage nach dem „richtigen“ Kollektortyp initiierte das KOMPETENZZENTRUM SOLARTECHNIK der Fachhochschule Ingolstadt ein Demonstrationsvorhaben zur experimentellen Untersuchung einer entsprechenden Anlage. So wurde ein solarunterstütztes Gebäudeheizungssystem in einem für den süddeutschen Gebäudebestand repräsentativen Zweifamilienhaus realisiert und mit umfangreicher Messtechnik ausgestattet. Die Heizungsanlage besteht aus einem Schichtspeicher (800 l), einem Flachkollektorfeld (Bruttofläche: 6,42 m²) und einem Feld direktdurchströmter Vakuumröhrenkollektoren (15,6 m²). Als zusätzlicher Wärmeerzeuger ist ein Ölkessel (22 kW) vorhanden. Messtechnisch erfasst werden alle Wärmeerzeuger und -verbraucher sowie die Wetterbedingungen. Es zeigt sich in diesem Projekt, dass der Einsatz von solarer Heizungsunterstützung auch in bestehenden Gebäuden durchaus Sinn macht und nennenswerte Brennstoff- und damit CO2-Einsparungen erreicht werden können, falls bestimmte Voraussetzungen erfüllt sind. Als sehr vorteilhaft am beschriebenen Gebäude muss dabei gewertet werden, dass der Heizwärmebedarf in weiten Teilen über Fußbodenheizsysteme mit niedriger Vorlauftemperatur abgedeckt wird. So ist die Einbindung der Solarsysteme in eine bestehende Heizungsanlage unter Weiterverwendung vorhandener Komponenten möglich und besonders sinnvoll. Es zeigte sich im Projektverlauf jedoch, dass die hydraulische und regelungstechnische Realisierung solcher verhältnismäßig komplexer Anlagen äußerste Sorgfalt erfordert. Hinsichtlich der Tauglichkeit der beiden Kollektortypen für solare Heizungsunterstützung bleibt festzuhalten, dass sowohl der eingesetzte Vakuumröhrenkollektor als auch der Flachkollektor prinzipiell dafür als sehr geeignet erscheinen. Dabei blieb der Vakuumröhrenkollektor jedoch hinter dem erwarteten Mehrertrag gegenüber dem Flachkollektor deutlich zurück. So offenbarte der Vakuumröhrenkollektor gerade im realen Winterbetrieb, der eigentlich eine Stärke dieses Kollektortyps darstellen sollte, konzeptionelle Schwächen. Nicht zuletzt angesichts der Tatsache, dass der Vakuumröhrenkollektor selbst bei relativ niedrigen Außentemperaturen keinen beträchtlichen Mehrertrag erbrachte, erscheint damit der Flachkollektor für solare Heizungsunterstützung auch in der Übergangszeit als technisch wie wirtschaftlich äußerst interessante Alternative. N2 - The CENTRE OF EXCELLENCE FOR SOLAR ENGINEERING of Ingolstadt University of Applied Sciences investigated a solar-assisted heating system in a two-family-house. The major targets of this project were the demonstration of solar energy utilisation in redeveloped family-houses as well as its potential of CO2 emission reduction. Furthermore, the behaviour of modern vacuum-tube and flat-plate collectors regarding hot water preparation and space heating was examined. The building, a two-family house, typical for rural regions, is located in the Bavarian countryside. It was originally built in the 1970ies and was modernised in the early 1990ies. A conservatory is integrated in the building. The building structure has a relatively high standard of thermal insulation. The existing heating system (oil furnace, flat-plate collectors, floor heating) was modified in this project by the integration of modern vacuum-tube collectors and a stratification tank. The building is equipped with flatplate collectors (6.42 m²), vacuum tube collectors (15.6 m²), a stratification tank (800 l) and an oil furnace (22 kW). Measurement equipment was installed in the building to monitor the thermodynamic behaviour of the components within the system, especially the solar fraction of both the vacuum-tube collectors and the flat-plate collectors. Apart from that, the storage tank was investigated mainly concerning stratification. The investigation showed that both collector types are suitable for solar-assisted heating systems. Both collector types work satisfying regarding their energy yield and the temperature levels delivered. Unexpectedly, the flat-plate collectors show a more favourable performance within this system than the vacuum tube collectors especially during winter time. This seems to be due to the vacuum-tube collectors being frosted comparably long. Apart from that, snow obviously covered the vacuum-tube collectors longer than the flat-plate collectors. The snow slipped off the flat-plate collectors’ glass cover but got stuck between the tubes of the vacuum-tube collectors. In general, both collector types are considered to be suitable for solar-assisted heating in Central European climates. The vacuum-tube collector, however, does not reach the additional energy yield expected. Thus, the flat-plate collector proves to be an interesting alternative for those systems. On the contrary, in winter times, which would be expected to be more favourable for the vacuum-tube collector, this collector type offered conceptual weaknesses. KW - Heizung KW - Thermische Solaranlage Y1 - 2005 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-3635 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 - CHAP A1 - Schmitt, David A1 - Reum, Tobias A1 - Summ, Thorsten A1 - Trinkl, Christoph A1 - Schrag, Tobias ED - Fink, Christian ED - Brunner, Christoph T1 - Investigation of the Flexibility Potential by Decoupling Building Mass and Room Temperature T2 - International Sustainable Energy Conference - Proceedings N2 - Using the thermal building mass as a thermal storage received increasing attention in research during recent years. Due to the large mass of concrete, it offers a large storage capacity and thus a high potential for flexibility. However, passive heat losses during cool down of a thermally activated building influence room temperature and thus limit its flexibility potential. In this contribution a multi-layer activation concept was investigated which thermally decouples the building mass and room air. The study aims to analyse the cool down of a thermally activated building in terms of different charging parameters while considering other heat sources such as solar gains. A dynamic building simulation of a demonstration building was set-up and compared to simulative studies from literature to proof the validity of its dynamic behaviour. In the simulation model the room temperature could be kept above 19 °C between 100 - 190 h. However, when charging the building structure quickly, room temperatures above 24 °C are reached easily. Considering other heat sources such as solar gains, advanced control algorithms are required for efficient operation of the heating system. UR - https://doi.org/10.52825/isec.v1i.1165 Y1 - 2024 UR - https://doi.org/10.52825/isec.v1i.1165 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-56543 SN - 2976-2030 PB - TIB Open Publishing CY - Hannover ER - TY - JOUR A1 - Reum, Tobias A1 - Schmitt, David A1 - Summ, Thorsten A1 - Trinkl, Christoph A1 - Ochs, Fabian A1 - Schrag, Tobias T1 - Experimental analysis of parallel operation of two heat sources in a dual-source heat pump incorporating two compressors JF - International Journal of Refrigeration N2 - Dual-source heat pumps have the potential to improve heating efficiency and / or the space required for heat sources. Parallel operation of two heat sources using two compressors can increase these benefits but poses technological challenges – specifically in the increased refrigerant cycle interconnection complexity, refrigerant and compressor oil management. These benefits and challenges have yet to be thoroughly investigated which is the primary objective of this research paper. An experimental analysis was conducted on a dual-source heat pump that utilized both an air heat source and a ground heat source. It included both individual and parallel operation modes of the heat sources. A prototype with a novel two-compressor interconnection was designed, manufactured, and tested in laboratory conditions. Analysis of the energetic benefit included efficiency evaluation at different ambient conditions and the corresponding loads on the ground source heat exchanger. Energetically, the single source operation showed comparable results in the coefficient of performance to conventional heat pumps despite the increased interconnection complexity. Parallel operation could efficiently cover heating loads at reduced load on the individual heat sources (at -7 °C, a reduction to 41 % on the ground-source and 58 % on the air-source heat exchanger). Technological challenges were highlighted in refrigerant and compressor oil shifts. While a control-based solution for the refrigerant shift was demonstrated, the oil shift requires further analysis of oil conditions in failing compressors. UR - https://doi.org/10.1016/j.ijrefrig.2024.12.013 Y1 - 2024 UR - https://doi.org/10.1016/j.ijrefrig.2024.12.013 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-57723 SN - 1879-2081 SN - 0140-7007 VL - 2025 IS - 171 SP - 124 EP - 138 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Bugaje, Aminu A1 - Yadav, Akhilesh A1 - Mehta, Kedar A1 - Ojinji, Felicia A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried ED - Schulz, Detlef 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://www.vde-verlag.de/proceedings-en/565651017.html SN - 978-3-8007-5651-3 SN - 978-3-8007-5652-0 N1 - Auch veröffentlicht auf IEEE: https://ieeexplore.ieee.org/document/9698257 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://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 - 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 - 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 - ACM 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 - 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 - 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 - 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 - 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 - 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 -