@inproceedings{MastHolzhammerPhilipp2018, author = {Mast, Tanja and Holzhammer, Uwe and Philipp, Matthias}, title = {SmartBio : Biogasanlagen als Akteur in neuen intelligenten, regionalen M{\"a}rkten}, booktitle = {Tagungsband 12. Rostocker Bioenergieforum 2018}, editor = {Nelles, Michael}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009-473-0}, url = {https://www.openagrar.de/receive/dimport_mods_00001878}, pages = {143 -- 150}, year = {2018}, language = {de} } @inproceedings{MastNagelHolzhammeretal.2020, author = {Mast, Tanja and Nagel, Sylvio and Holzhammer, Uwe and Eltrop, Ludger}, title = {Biogasanlagen neu denken}, booktitle = {Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV}, subtitle = {technisch-{\"o}konomische Charakterisierung f{\"u}r die Einbindung in die modellgest{\"u}tzte Systemanalyse}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009-507-2}, doi = {https://doi.org/10.18453/rosdok_id00002650}, pages = {123 -- 132}, year = {2020}, language = {de} } @inproceedings{NagelMastHolzhammeretal.2020, author = {Nagel, Sylvio and Mast, Tanja and Holzhammer, Uwe and Eltrop, Ludger}, title = {Die Rolle der Bioenergie im Energie- und Mobilit{\"a}tssystem in Deutschland}, booktitle = {Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV}, subtitle = {Ergebnisse einer modellgest{\"u}tzten Systemanalyse}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009- 507-2}, doi = {https://doi.org/10.18453/rosdok_id00002650}, pages = {47 -- 56}, year = {2020}, language = {de} } @inproceedings{MastKollerHolzhammer2020, author = {Mast, Tanja and Koller, Maria and Holzhammer, Uwe}, title = {Verf{\"u}gbarkeit und Erl{\"o}sm{\"o}glichkeiten unterschiedlicher Biogasanlagenkonzepte im Smart-Market-Ansatz}, booktitle = {Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009- 507-2}, doi = {https://doi.org/10.18453/rosdok_id00002650}, pages = {391 -- 397}, year = {2020}, language = {de} } @article{ElMakroumKhallaayounLghouletal.2023, author = {El Makroum, Reda and Khallaayoun, Ahmed and Lghoul, Rachid and Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {Home Energy Management System Based on Genetic Algorithm for Load Scheduling: A Case Study Based on Real Life Consumption Data}, volume = {16}, pages = {2698}, journal = {Energies}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en16062698}, year = {2023}, abstract = {This paper proposes a home energy management system able to achieve optimized load scheduling for the operation of appliances within a given household. The system, based on the genetic algorithm, provides recommendations for the user to improve the way the energy needs of the home are handled. These recommendations not only take into account the dynamic pricing of electricity, but also the optimization for solar energy usage as well as user comfort. Historical data regarding the times at which the appliances have been used is leveraged through a statistical method to integrate the user's preference into the algorithm. Based on real life appliance consumption data collected from a household in Morocco, three scenarios are established to assess the performance of the proposed system with each scenario having different parameters. Running the scenarios on the developed MATLAB script shows a cost saving of up to 63.48\% as compared to a base scenario for a specific day. These results demonstrate that significant cost saving can be achieved while maintaining user comfort. The addition of supplementary shiftable loads (i.e., an electric vehicle) to the household as well as the limitations of such home energy management systems are discussed. The main contribution of this paper is the real data and including the user comfort as a metric in in the home energy management scheme.}, language = {en} } @article{KaminskiKuesterDanielAokietal.2023, author = {Kaminski K{\"u}ster, Kristie and Daniel, Gebbran and Aoki, Alexandre Rasi and Lambert-Torres, Germano and Navarro Gevers, Daniel and Impinnisi, Patricio and da Silva Pinto, Cleverson Luiz}, title = {Adoption of Local Peer-to-Peer Energy Markets: Technical and Economical Perspectives for Utilities}, volume = {16}, pages = {2364}, journal = {Energies}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en16052364}, year = {2023}, abstract = {Peer-to-peer (P2P) energy markets constitute a promising approach for locally coordinating the increasing amount of distributed energy resources (DERs) in the distribution system. Although the benefits of P2P markets for the prosumers are already well understood, their impact on utilities is not well discussed nor well understood. This hinders the development of regulatory frameworks, which are still needed to allow for the widespread adoption of decentralized energy markets in any interested country. So far, research has been conducted in specific isolated aspects, making it difficult to understand the overall implications for utilities. The present study aims to tackle this research gap by comprehensively evaluating P2P markets' effects, considering utilities as primary stakeholders. A qualitative roadmap with the overall benefits and challenges of adopting P2P by utilities is outlined to reach this purpose. Technical and economic criteria are assigned for comparing a P2P market to the current regulatory framework. Each criterion is evaluated in a co-simulation platform connecting a market model to a power flow model. Market performance is assessed by revenue analysis, and grid operation indicators evaluate grid performance. Furthermore, network fees are introduced as compensation mechanisms for the net revenue loss. Comparison scenarios encompass network fees and the number of agents, PV, and storage penetration. Results demonstrate that there is no possible benefit for both utilities and prosumers simultaneously if looking exclusively at the financial balance of the market. An equilibrium in benefits for all stakeholders is achievable if non-financial metrics are considered in an integrated market and fee structure analysis. Moreover, results demonstrate that the design of market structures must be sensitive to network configurations and DER penetration changes. This study contributes toward comprehending how the utilities could embrace P2P markets as a feasible solution for grid coordination challenges, opening a new set of questions for further research.}, language = {en} } @article{StoecklIddaSelleneitetal.2023, author = {St{\"o}ckl, Martin and Idda, Johannes and Selleneit, Volker and Holzhammer, Uwe}, title = {Flexible Operation to Reduce Greenhouse Gas Emissions along the Cold Chain for Chilling, Storage, and Transportation - A Case Study for Dairy Products}, volume = {15}, pages = {15555}, journal = {Sustainability}, number = {21}, publisher = {MDPI}, address = {Basel}, issn = {2071-1050}, doi = {https://doi.org/10.3390/su152115555}, year = {2023}, abstract = {The further expansion of renewable energies in Germany requires flexible consumers to balance fluctuations in electricity production from variable renewable energies. Cold storage warehouses, due to their inherent storage capacity and widespread use, are well-suited for integrating more renewable energies. The potential of cold storage warehouses is often viewed in isolation and not in conjunction with the cold chain's upstream and downstream processes. By adjusting the temperatures within the processes, the individual links in the cold chain can be made flexible. To assess the effects of flexibilization on emissions and electricity costs, thermodynamic models of the individual links in the cold chain and of a yogurt pallet are developed and linked together. Due to temperature fluctuations in the products resulting from the flexibilization, emission evaluations must be considered throughout the cold chain. Results of the simulation for the study period show that emissions reductions and electricity cost savings can be achieved in all three links when they are made flexible. However, the savings vary in magnitude. Only minor savings can be achieved in the cooling tunnel. The greatest potential for savings is in refrigerated transport, if deeper cooling occurs in the process before, i.e., in the cold storage warehouse.}, language = {en} } @inproceedings{SchmittReumSummetal.2024, author = {Schmitt, David and Reum, Tobias and Summ, Thorsten and Trinkl, Christoph and Schrag, Tobias}, title = {Potential of a Long-Term Predictive Controller for Managing Energy Storages to Reduce the Electric Grid-Load of an Air-Source Heat Pump}, booktitle = {Proceedings of the International Renewable Energy Storage and Systems Conference (IRES 2023)}, editor = {Droege, Peter and Quint, Lelia}, publisher = {Atlantis Press}, address = {Dordrecht}, isbn = {978-94-6463-455-6}, doi = {https://doi.org/10.2991/978-94-6463-455-6_21}, pages = {205 -- 211}, year = {2024}, abstract = {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.}, language = {en} } @article{SelleneitHolzhammer2024, author = {Selleneit, Volker and Holzhammer, Uwe}, title = {Eigenenergieversorgung oder mehr Resilienz durch Flexibilisierung?}, volume = {1}, journal = {VDI energie + umwelt}, number = {5-6}, publisher = {VDI Fachmedien}, address = {D{\"u}sseldorf}, issn = {2942-7347}, doi = {https://doi.org/10.37544/2942-7347-2024-5-6-53}, pages = {53 -- 57}, year = {2024}, language = {de} } @article{MehtaShahZoerner2024, author = {Mehta, Kedar and Shah, Meeth Jeetendra and Z{\"o}rner, Wilfried}, title = {Agri-PV (Agrivoltaics) in Developing Countries: Advancing Sustainable Farming to Address the Water-Energy-Food Nexus}, volume = {17}, pages = {4440}, journal = {Energies}, number = {17}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en17174440}, year = {2024}, abstract = {The escalating demand for water, energy, and food, coupled with the imperative for sustainable development, necessitates innovative solutions to address the complex interdependencies within the water-energy-food nexus. In this context, agriculture and photovoltaics (Agri-PV or Agri-voltaics) systems have emerged as a promising approach to promoting sustainable agricultural practices while enhancing energy efficiency and food production. However, limited research, especially on the technical aspects of Agri-PV, has resulted in a knowledge gap regarding how to model and determine the suitability of Agri-PV for different crops based on local conditions. This study presents a novel approach to modeling and simulating Agri-PV systems for various major crops in developing countries, using Uzbekistan as a case study. It provides a blueprint for selecting suitable Agri-PV systems. The research investigates the technical feasibility of Agri-PV technology tailored to Uzbekistan's agricultural landscape, with broader implications for Central Asia. Employing a systematic methodology, the study begins by selecting appropriate sites and crops for Agri-PV system testing, ensuring the relevance and applicability of the research findings to the local context. Using advanced software tools such as PVSyst, the study accurately calculates photosynthetically active radiation (PAR) values specific to selected crops, bridging a significant knowledge gap and providing empirical data essential for informed decision making. The methodology further incorporates an in-depth analysis of economic and technical considerations in selecting PV modules and inverters, enhancing the scientific accuracy of the study. By strategically modeling Agri-PV systems based on parameters like row density, module distance, and tilt angle, this research aims to optimize the integration of photovoltaic technology with agricultural practices in Uzbekistan. Moreover, this study helps to understand the impact of Agri-PV systems on the water-energy-food nexus, providing valuable insights into the potential benefits and challenges specific to the region. The study identifies the positive impact of Agri-PV on major crops and provides a suitable design and modeling approach for sustainable farming practices.}, language = {en} } @article{VannahmeEhrenwirthSchrag2024, author = {Vannahme, Anna and Ehrenwirth, Mathias and Schrag, Tobias}, title = {Development and application of a guideline for assessing optimization potentials for district heating systems}, volume = {2024}, pages = {131226}, journal = {Energy}, number = {297}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-6785}, doi = {https://doi.org/10.1016/j.energy.2024.131226}, year = {2024}, abstract = {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.}, language = {en} } @article{BazziElHafdaouiKhallaayounetal.2023, author = {Bazzi, Ahmed and El Hafdaoui, Hamza and Khallaayoun, Ahmed and Mehta, Kedar and Ouazzani, Kamar and Z{\"o}rner, Wilfried}, title = {Optimization Model of Hybrid Renewable Energy Generation for Electric Bus Charging Stations}, volume = {17}, pages = {53}, journal = {Energies}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en17010053}, year = {2023}, abstract = {This paper introduces a comprehensive approach for sizing grid-connected hybrid renewable energy systems tailored for electric bus fleet operations. The study involves two main steps. First, a mathematical model that optimizes the configuration of such systems by considering daily electric bus consumption, solar irradiance, wind speed, and biomass potential is formulated. The model utilizes Pareto frontier multi-objective optimization to minimize the net present cost, the cost of energy, and greenhouse gas emissions. Second, the model is rigorously applied and tested in a real-world case study in Fez, Morocco, using HOMER Pro; the case study centers on the daily energy requirements of the buses, estimated at 2.5 megawatt hours per day, with a peak demand of 345 kilowatts. Two scenarios are explored, revealing a discernible trade-off dilemma between the full hybrid renewable energy scenario (Scenario 1) and the grid-connected hybrid renewable energy scenario (Scenario 2). In Scenario 2, the grid-connected hybrid renewable energy system demonstrates a notable 42.8\% reduction in the net present cost, totaling USD 984,624. Similarly, the levelized cost of energy experiences a significant decrease, reaching approximately 0.08 USD/kWh, marking a 38.1\% reduction. However, this apparent economic advantage is juxtaposed with a critical consideration—an increase in greenhouse gas emissions from null to 330,418 kg/year.}, language = {en} } @article{BachseitzSheryarSchmittetal.2024, author = {Bachseitz, Michael and Sheryar, Muhammad and Schmitt, David and Summ, Thorsten and Trinkl, Christoph and Z{\"o}rner, Wilfried}, title = {PV-Optimized Heat Pump Control in Multi-Family Buildings Using a Reinforcement Learning Approach}, volume = {17}, pages = {1908}, journal = {Energies}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en17081908}, year = {2024}, abstract = {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.}, language = {en} } @article{SummOyinlolaKhattaketal.2024, author = {Summ, Thorsten and Oyinlola, Muyiwa and Khattak, Sanober and Ehrenwirth, Mathias and Trinkl, Christoph and Z{\"o}rner, Wilfried}, title = {Towards maximum cost-effectiveness: multi-objective design optimisation of insulating glass flat-plate collectors}, volume = {2025}, pages = {124594}, journal = {Applied Thermal Engineering}, number = {258}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1359-4311}, doi = {https://doi.org/10.1016/j.applthermaleng.2024.124594}, year = {2024}, abstract = {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.}, language = {en} } @article{LwakatareVyavahareMehtaetal.2024, author = {Lwakatare, Bertha and Vyavahare, Priyanka and Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {Electrification Planning for Off-Grid Communities in Sub-Saharan Africa: Advancing Energy Access}, volume = {17}, pages = {5994}, journal = {Energies}, number = {23}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en17235994}, year = {2024}, abstract = {Sub-Saharan Africa, especially its rural areas, faces significant challenges in achieving universal electrification despite its abundant renewable energy resources. The region has the highest population without access to electricity, largely due to economic, infrastructural, and geographical barriers. Energy poverty is a critical issue that hinders sustainable development and exacerbates inequalities. Namibia's sustainable energy policy aligns with the global Sustainable Development Goals (SDGs), particularly SDG 7, which aims to provide affordable and reliable modern energy access for all. The policy emphasizes mini-grids and decentralized power systems as key strategies for rural electrification. However, despite increased deployment of mini-grids, these solutions often struggle with long-term sustainability. This research explores cost-effective electrification strategies through scenario-based modeling to reduce energy poverty and expand energy access in Namibia's rural communities, focusing on the existing mini-grids in Tsumkwe and Gam. Using a comprehensive methodology that incorporates HOMER Pro for mini-grid capacity expansion and MS Excel for evaluating main-grid extensions, this study aims to identify the most feasible and economical electrification solutions. The analysis compares electricity supply, total net present cost, and the levelized cost of electricity across these systems. The findings will offer insights into addressing energy poverty in Namibia and provide recommendations for sustainable and scalable rural electrification across Sub-Saharan Africa.}, language = {en} } @article{MirzaqobulovMehtaIlyasetal.2024, author = {Mirzaqobulov, Jakhongirmirzo and Mehta, Kedar and Ilyas, Sana and Salokhiddinov, Abdulkhakim}, title = {The Role of Collector-Drainage Water in Sustainable Irrigation for Agriculture in the Developing World: An Experimental Study}, volume = {6}, journal = {World}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {2673-4060}, doi = {https://doi.org/10.3390/world6010001}, year = {2024}, abstract = {This study investigates the feasibility of using mineralized collector-drainage water (CDW) for irrigating maize crops on light gray soils in the Syrdarya region of Uzbekistan, an area facing severe water scarcity and soil salinity challenges. The research is particularly novel as it explores maize production in marginalized soils, a subject previously unexamined in this context. The experiment was designed as a three-factor factorial study with three replications, following the guidelines of the Uzbekistan Cotton Scientific Research Institute. Five irrigation treatments (Fresh Water, Fresh Water 70\% vs. CDW 30\%, Complex Method (Mixing with Specific Rules), CDW 70\% vs. Fresh Water 30\% (Mixing) and only CDW) were evaluated using an Alternate Furrow Irrigation system, incorporating various mixtures of fresh water and CDW to determine their effects on soil salinity, crop health and yield. The amount of irrigation water required was determined using a soil moisture balance model, with soil samples collected at multiple depths (0-100 cm) to monitor changes in moisture content and salinity. Salinity levels and soil health parameters such as alkalinity, chloride, sulfate and cation/anion balances were measured at different stages of crop growth. Data were collected over three growing seasons (3 years). An analysis of the data revealed that using CDW, even in mixtures with fresh water, can sustain crop production while managing soil salinity. Notably, irrigation methods such as Mixing 70-30 and the Complex Mixing Method effectively reduced freshwater dependency and maintained the crop yield without significantly increasing salinity. The results suggest that CDW could be a viable alternative water source in regions where traditional water resources are limited. The findings have significant implications for improving water use efficiency and agricultural productivity in areas facing similar environmental challenges. This research not only contributes to the broader understanding of sustainable irrigation practices in arid regions but also provides a scientific basis for the wider adoption of CDW in Uzbekistan, potentially enhancing food security and supporting long-term agricultural sustainability in the region.}, language = {en} } @article{MehtaZoerner2023, author = {Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {Cracking the code: mapping residential building energy performance in rural Central Asia through building typologies}, volume = {5}, pages = {349}, journal = {SN Applied Sciences}, number = {12}, publisher = {Springer Nature}, address = {Cham}, issn = {2523-3971}, doi = {https://doi.org/10.1007/s42452-023-05607-1}, year = {2023}, abstract = {Buildings in rural Central Asia have unique characteristics as they were built during the Soviet era (during 1950-1960) without any energy efficiency measures. The special and aged building stock pose a crucial challenge on energy security and energy supply. However, accurate scientific data on their energy usage is lacking, highlighting a research gap about robust and validated methodology to determine the energy use of rural Central Asian buildings. In response to this need, this research paper proposes a set of generalised residential building typologies for rural Central Asia, with a focus on Kyrgyzstan. The study combines quantitative and qualitative methods, including household surveys, energy demand modelling, EnergyPlus simulations, and result validation. It derives energy-based building typologies from construction year and building envelope characteristics. Through numerous validated simulations, it was identified that the heat demand for rural Kyrgyz houses is 3-5 times here compared to European houses (250-400 kWh/m2). The study revealed the estimated heat demand for homes in rural Kyrgyzstan, indicating a significant potential for improving building energy efficiency in the region. These results can inform specific approaches, such as building renovation plans, energy certification, and renovation strategies. Furthermore, the validated methodology introduced offers opportunities for researchers in the field of building energy efficiency and can be applied to similar regions in Central Asia with comparable building stocks and climates.}, language = {en} } @article{SummOyinlolaKhattaketal.2023, author = {Summ, Thorsten and Oyinlola, Muyiwa and Khattak, Sanober and Trinkl, Christoph and Z{\"o}rner, Wilfried}, title = {Statistical analysis of solar thermal collectors in the Solar Keymark Database}, volume = {2024}, pages = {103581}, journal = {Sustainable Energy Technologies and Assessments}, number = {61}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2213-1396}, doi = {https://doi.org/10.1016/j.seta.2023.103581}, year = {2023}, abstract = {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.}, language = {en} } @article{MehtaZoerner2025, author = {Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {Crop selection in Agri-PV: international review based strategic decision-making model}, volume = {2025}, pages = {100143}, journal = {Solar Compass}, number = {16}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2772-9400}, doi = {https://doi.org/10.1016/j.solcom.2025.100143}, year = {2025}, abstract = {Agri-Photovoltaics (Agri-PV) is well known for its dual land use, integrating solar energy generation with agricultural production. This not only optimizes land use but also enhances food and energy security. Since Agri-PV is closely linked with crop cultivation, it is not solely about energy generation but also requires careful consideration of crop suitability within Agri-PV installations. Despite its significance, there is limited information available to guide decision-making for crop selection in Agri-PV systems. Selecting suitable crops remains a complex challenge, as factors such as shading tolerance, water requirements, and economic viability vary across different geographical and climatic conditions. This study develops a novel, review-based decision support model for crop selection in Agri-PV systems, synthesizing international research and case studies to provide a structured framework for decision-making. The model is based on 12 main crop typologies and key parameters such as water use, shading adaptability, crop yield/economic potential, and space requirements, derived from 117 research articles and case studies from 25 countries. By leveraging insights from successful international implementations, the model provides a practical framework for policymakers, farmers, and energy planners to enhance the sustainability and efficiency of Agri-PV projects. Findings suggest that crop selection strategies must align with regional climate conditions and PV system design to maximize synergies between energy and food production. High-value crops that require less space and have higher shade tolerance are more suitable for small-scale or decentralized Agri-PV systems. Future research should focus on advanced modeling techniques, AI-driven optimization, and real-world pilot studies to further refine decision-making in Agri-PV deployment. This study contributes to the growing body of knowledge on Agri-PV systems by providing a novel crop suitability matrix for effective decision-making.}, language = {en} } @article{VannahmePatelSchmittetal.2024, author = {Vannahme, Anna and Patel, Dharmik and Schmitt, David and Summ, Thorsten and Trinkl, Christoph and Schrag, Tobias}, title = {Technical and economic analysis of digitally controlled substations in local district heating networks}, volume = {2024}, pages = {133585}, journal = {Energy}, number = {312}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0360-5442}, doi = {https://doi.org/10.1016/j.energy.2024.133585}, year = {2024}, abstract = {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.}, language = {en} } @article{TutunaruBoschGresshakeetal.2023, author = {Tutunaru, Robin and Bosch, Stephan and Greßhake, Lukas and Holzhammer, Uwe}, title = {Ein Konzept f{\"u}r eine GIS-gest{\"u}tzte Visualisierung der spezifischen Anforderungen von regionalen Akteuren der Energiewende an die Landnutzung}, volume = {2023}, journal = {AGIT: Journal f{\"u}r Angewandte Geoinformatik}, number = {9}, publisher = {Wichmann Verlag}, address = {Berlin}, issn = {2509-713X}, doi = {https://doi.org/10.14627/537742005}, pages = {44 -- 49}, year = {2023}, abstract = {F{\"u}r eine nachhaltige Energiewende werden Konzepte ben{\"o}tigt, welche die techno-{\"o}konomische und sozial-{\"o}kologische Komplexit{\"a}t regionaler Standortentscheidungen f{\"u}r erneuerbare Energien (EE) visualisieren k{\"o}nnen. Dabei m{\"o}chten wir die Ergebnisse mittels Geographischer Infor-mationssysteme (GIS) so visualisieren, dass sie von jedem Akteur nachvollzogen werden k{\"o}nnen und einen konstruktiven Austausch zur Wertigkeit bestimmter Fl{\"a}chen zwischen allen Akteuren erlauben.}, language = {de} } @inproceedings{MastHuemmerHolzhammer2022, author = {Mast, Tanja and H{\"u}mmer, Benedikt and Holzhammer, Uwe}, title = {Smart Markets als marktbasierte Erg{\"a}nzung zum deutschen Engpassmanagement}, booktitle = {17. Symposium Energieinnovation}, subtitle = {Konzeptionierung anhand eines Modellbeispiels}, publisher = {Technische Universit{\"a}t Graz}, address = {Graz}, url = {https://www.tugraz.at/events/eninnov2022/nachlese/download-beitraege/stream-a/\#c318498}, year = {2022}, language = {de} } @article{StoecklHolzhammer2024, author = {St{\"o}ckl, Martin and Holzhammer, Uwe}, title = {Integration von Flexibilit{\"a}t in die Energieversorgung}, volume = {35}, journal = {Ern{\"a}hrung aktuell - der Lebensmittelbrief}, subtitle = {Ein Aspekt zur Erreichung der Klimaziele und zur Stabilisierung der Energiekosten - Fallbeispiel K{\"u}hlhaus}, number = {Mai/Juni}, publisher = {LID}, address = {Lampertheim}, issn = {1866-6787}, pages = {46 -- 47}, year = {2024}, language = {de} } @inproceedings{MastHuemmerHolzhammer2021, author = {Mast, Tanja and H{\"u}mmer, Benedikt and Holzhammer, Uwe}, title = {Potential of Demand Side Management and Biogas Plants in regional market-based Congestion Management}, booktitle = {ENERDAY 15th Conference on Energy Economics and Technology "Creative Destruction? Disruptive innovation in times of Covid and an accelerated energy system transformation": Book of Abstracts}, publisher = {TU Dresden}, address = {Dresden}, url = {https://tu-dresden.de/bu/wirtschaft/bwl/ee2/tagungen/enerday-archives}, pages = {22 -- 23}, year = {2021}, language = {en} }