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 -