TY - JOUR A1 - Vannahme, Anna A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias T1 - Enhancement of a district heating substation as part of a low-investment optimization strategy for district heating systems JF - Resources N2 - In an ongoing project, low-investment measures for the optimization of district heating systems are analyzed. The optimization strategies are collected in a catalog, which is the core of a guideline. The application of this guideline is demonstrated using two concrete district heating networks as examples. In this study, the improvement of an analog controlled district heating substation by an electronic controller is investigated. High supply temperatures and heat losses are often a challenge in district heating networks. The district heating substations have a major influence on the network return temperatures. The comparison of the two substation setups with analog and electronic controllers is carried out by laboratory measurement. It can be shown that the return temperatures can be reduced by an average of 20 K in winter and transition, as well as 16 K in summer. The district heating network losses are calculated for one of both specific district heating networks. They are calculated from the ratio of network losses to generated energy. The generated energy is the sum of network losses and consumer demand. The thermal losses of the network can be reduced by 3%. The volume flow in the heating network can be reduced to a quarter. Therefore, the pumping energy requirement drops sharply since these changes cubically affect the volume flow UR - https://doi.org/10.3390/resources10050053 KW - district heating substation KW - control KW - optimization KW - local district heating networks KW - non-retrofitted single-family houses KW - thermal test rig Y1 - 2021 UR - https://doi.org/10.3390/resources10050053 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-10951 SN - 2079-9276 VL - 10 IS - 5 PB - MDPI CY - Basel ER - TY - CHAP A1 - Schrag, Tobias A1 - Ehrenwirth, Mathias A1 - Ramm, Tobias A1 - Vannahme, Anna A1 - Trinkl, Christoph ED - Belasri, Ahmed ED - Beldjilali, Sid Ahmed T1 - Solar energy use in district heating networks T2 - ICREEC 2019: Proceedings of the 1st International Conference on Renewable Energy and Energy Conversion UR - https://doi.org/10.1007/978-981-15-5444-5_1 KW - district heating systems KW - solar energy KW - heat pumps Y1 - 2020 UR - https://doi.org/10.1007/978-981-15-5444-5_1 SN - 978-981-15-5443-8 SN - 978-981-15-5446-9 SN - 978-981-15-5444-5 SN - 2352-2534 SN - 2352-2542 N1 - Access provided by Nationallizenz Ebooks Medicine SP - 3 EP - 10 PB - Springer CY - Singapur ER - TY - CHAP A1 - Vannahme, Anna A1 - Ramm, Tobias A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias ED - Haumer, Anton T1 - Comparison of a usual heat-transfer-station with a hydraulic modified version under the aspect of exergy saving T2 - Proceedings of the 13th International Modelica Conference UR - http://dx.doi.org/10.3384/ecp19157647 KW - heat-transfer-station KW - hydraulic system KW - control design KW - district heating KW - single-family house Y1 - 2019 UR - http://dx.doi.org/10.3384/ecp19157647 SN - 978-91-7685-122-7 SN - 1650-3686 SN - 1650-3740 SP - 647 EP - 654 PB - Linköping University Electronic Press CY - Linköping ER - TY - JOUR A1 - Vannahme, Anna A1 - Busch, Jonas A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias T1 - Experimental Study of District Heating Substations in a Hardware-in-the-Loop Test Rig JF - Resources N2 - This study compares two district heating substation systems for implementation in rural district heating networks with non-retrofitted single- and two-family houses. The aim is to determine which system has the potential to provide lower return temperatures and/or lower power peak demand. A hardware-in-the-loop-test rig was utilized to measure the two district heating substations under real operation conditions. This experimental study demonstrates that load balancing of the district heating network is attainable with the district heating substation with storage. This is especially advantageous when there is a high demand for domestic hot water. Overall, both systems yield comparable return temperatures. UR - https://doi.org/10.3390/resources12040043 KW - district heating substation KW - local district heating network KW - non-retrofitted single- and two-family-houses KW - thermal hardware-in-the-loop test rig Y1 - 2023 UR - https://doi.org/10.3390/resources12040043 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-33382 SN - 2079-9276 VL - 12 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vannahme, Anna A1 - Ehrenwirth, Mathias A1 - Schrag, Tobias T1 - Development and application of a guideline for assessing optimization potentials for district heating systems JF - Energy N2 - Integrating renewable energies into district heating systems has a large potential to reduce CO2-emissions in the heating sector. As district heating systems offer the possibility of incorporating renewable energies into the heat supply, new systems have to be built and the existing networks must be maintained. This study investigates ways to optimize existing district heating systems in order to ensure economic sustainability in the long-term. Previous case studies have elaborated on a variety of optimization measures. However, to date, these measures have neither been collected nor consistently assessed for a wider application range. Therefore, in the study presented here a system for assessing the ecological and economic benefits of optimization measures was developed and applied. The assessment method utilized showed that optimization of district heating consumer substations and adding of a central buffer storage tank has a high optimization potential in comparison to intermittent operation strategy, which has a significantly lower optimization potential. From this information and the transferability data, a district heating operator can determine which optimization measure should be prioritized, which is shown at the end of the paper on an example case. UR - https://doi.org/10.1016/j.energy.2024.131226 Y1 - 2024 UR - https://doi.org/10.1016/j.energy.2024.131226 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-47196 SN - 1873-6785 SN - 0360-5442 VL - 2024 IS - 297 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - 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 -