TIB Open Publishing
Not a member yet
1994 research outputs found
Sort by
Investigation on the Injection of Exhaust Air Into Cavity Receivers
Full text linkConcentrating solar thermal (CST) systems stands out as a promising renewable energy technology, leveraging radiative heat transfer to convert solar irradiance into thermal energy. Central receiver systems (CRS), a form of CST, demonstrate potential for diverse industrial applications due to their ability to operate at high temperatures. However, optimizing their efficiency remains a challenge, particularly regarding the utilization of air as a heat transfer fluid (HTF). This study investigates the impact of exhaust air reinjection on the performance of cavity receiver systems in CST. Previous research has explored similar concepts, but gaps remain in directly modeling exhaust air return, especially in the context of cavity receivers. Using a finite element method (FEM) model this research examines various parameters affecting exhaust air injection, including injection ring height and outlet air flow velocity. Results indicate a dependency between exhaust air reinjection velocity, total mass flow rate, and the air return ratio (ARR). Higher injection velocities, coupled with increased mass flow rates, lead to greater exhaust air loss and lower ARR values. Through parametric analysis, insights are gained into the geometry parameters crucial for optimizing ARR and enhancing receiver efficiency. The highest ARR of greater than 95% is achievable when the air is injected close to the aperture in the radial directions and the fluid velocity is minimized through lower flowrates or increased inlet boundary area. These findings contribute to advancing the understanding and design of cavity receiver systems for improved renewable energy utilization
Materials Comparison for Reducing Heliostats Production Costs
Full text linkThe alarming issue of climate change and the necessity to increase the renewable energy stake has become the driving force for cost reduction measures taken in various renewable technologies. Concentrated Solar Power (CSP) is an increasingly attractive solar energy technology that uses heliostats to provide controllable, rapid heating and thermal energy storage (TES) benefits, which can use high temperature fluids (HTF) for higher efficiencies. The cost of installation for a commercial heliostat assuming a production volume of 22,239 heliostats, which represents a solar field aperture area of 1,078,592 m2, is $127/m2, or 136.98 million for the solar field [1]. Around 31% of the cost comes from manufactured parts which include the heavy use of steel, which can be subject to high price volatility, to ensure structural stability under wind load conditions. By studying the structural vibration response for different types of composite materials, a case can be made to switch from the heavy use of galvanized steel to a hybrid or even complete use of composite materials for heliostat construction. This paper presents a structural vibration response comparison between Steel AISI 1020, Glass Fiber Reinforced Polymer (S-Glass and E-Glass), Basalt Fiber Reinforced Polymer, and Carbon Fiber Reinforced Polymer (230, 290, and 395 GPa.) for heliostats structure manufacturing
Development of a new PVt / PCM System for Heating and Power
Full text linkThis study presents a PVt/PCM design that combines heat exchanger and PCM storage to increase power output. The PCM first absorbs sensible heat and when it reaches the melting temperature, it absorbs latent heat and continues to melt. When the phase change is complete, the temperature of the PCM starts to rise. The design consists of a PCM tank under the PV panels and a PCM heat box. In this design-free PVt/PCM system, the thermal efficiency is enhanced by the ability of the PCM to store excess heat during peak radiation periods, and this stored thermal energy can then be released when needed, allowing heat to be used more consistently and efficiently. Energy balance equations were used to determine the thermal energy of the PVt during the summer day in the UK. MATLAB simulations show different heat conduction rates in PCMs. Thermal efficiency measures the system\u27s effectiveness in converting solar energy into useful thermal energy. Incorporating PCM helps maintain PV cell temperatures, preserving electrical efficiency
Low-Loss Singulation of TOPCon Half Solar Cells by TLS and Al2O3 Edge Passivation
Full text linkThis work addresses the separation of tunnel-oxide passivated contact (TOPCon) host solar cells into half solar cells. It demonstrates the feasibility of achieving almost loss-free cell performance after edge passivation by the passivated edge technology (PET). It is shown that edge passivation with aluminum oxide (Al2O3) is also compatible with TOPCon solar cells that have been fabricated with Al-free Ag screen printing paste for the front side finger contacts applying laser-enhanced contact optimization (LECO). The half solar cells, with an edge length of 182 mm x 91 mm, are separated from industrial pseudo-square M10-format TOPCon host solar cells by thermal laser separation (TLS) from the front side. An optimized TLS process results in an efficiency loss of only slightly above 0.1%abs. A high-throughput prototype tool with a capacity of about 16,000 half solar cells per run is used for an Al2O3 layer deposition on the cut edges. Using optimized processes, the PET recovered approximately 85%rel of the cutting losses in pseudo fill factor by applying Al2O3 edge passivation and annealing. Thus, TLS in combination with high-throughput Al2O3 edge passivation is a viable approach for industrial fabrication of highly efficient TOPCon half solar cells, whether LECO and Al-free Ag pastes are applied or not
Battery Neighbourhood Storage for a Climate Protection Settlement
Full text linkThe strong expansion of renewable energies has led to the increasing importance of storage systems. Decentralized storage solutions, including home and neighbourhood storage systems, play an important role in this context. This study compares individual home storage systems with a common neighbourhood storage system. The use case is to optimize the use of photovoltaic energy generated in the settlement. The criteria investigated are the grade of autarky and self-consumption. A simulation tool was developed to perform load flow simulations based on household electricity consumption, electric vehicle charging profiles, heat pumps and photovoltaic generation data for different battery capacities and system boundaries. The results show that neighbourhood storage systems can achieve a maximum increase in the grade of autarky of up to 8.47 % and an increase in self-consumption of 6.87 % compared to individual home storage systems with equivalent cumulative battery capacities for the given use case. In the exemplary case the common neighbourhood storage requires only about halve of the battery capacity compared to the cumulated capacity of all individual storages to achieve the same grade of autarky for a typical operation case
Modeling Bus Traffic for the Berlin SUMO Traffic Scenario
Full text linkThe digital transformation of the transport sector in our cities will be led by the deployment of large-scale digital twins, interacting with their real world counterpart to model, predict, and improve movements and reoccurring patterns. Traffic simulation is an essential tool in this area. While both macroscopic and microscopic simulations are possible, only the latter provide enough detail to realize sophisticated Intelligent Traffic Systems (ITS).One of the biggest challenges is accurately modeling road traffic on a large scale due to limitations in both reliable data sources, as well as the quickly increasing complexity of size. Only a handful of city-scale traffic scenarios exist, and only a few of them include public transport modalities. With this paper, our aim is to extend this list by integrating bus traffic within the Berlin SUMO Traffic scenario (BeST). We provide an overview of potential data sources and a detailed description of the applied methodology. As the scenario was initially calibrated with only individual private traffic, we conduct an evaluation on how the added traffic volume affects the stability of the scenario
“Return to the Future” With a Systemic Agrivoltaic Strategy: A Path to Regenerate an Abandoned Rural Village and Revive Agriculture After the Xylella Olive Tree Disease in the Puglia Region (Southern Italy)
Full text linkThis paper examines a rural regeneration project combining a utility-scale agrivoltaic system with an innovative agricultural system involving intercropping olive trees with fodder, medicinal and melliferous crops. The resulting project serves as a potential best practice in the Mediterranean region, particularly in Puglia, southern Italy, where olive groves have been severely affected by a plant disease caused by the quarantine bacterium Xylella fastidiosa. The study takes an integrated approach, covering several design dimensions, including agricultural, environmental, ecological, energy, social, economic, and architectural considerations. The proposal to restore the abandoned rural village of Monteruga and revive its vibrant rural economy seems to be a coherent strategy of "going back to the future." The agrivoltaic system is integrated with other relevant components to promote multifunctional development and social innovation by leveraging the production and sale of renewable energy. The agrivoltaic facility\u27s temporary reinforcing action would boost an innovative rural development process, providing an appropriate regenerative response to the catastrophic effects of desiccation and uprooting of olive groves caused by Xylella. Rural regeneration is urgently needed and can be supported by optimized, specifically designed agrivoltaic systems, among other things. A transition period of at least 20 years is required for the associated agricultural system to become self-sustaining, with the option of replacing the agrivoltaic system entirely
CST Process Heat Solution for India’s Top Cancer Hospital With ANU’s BigDish: Study of Solar Thermal Powered Tri-Generation System
Full text linkIndia has an abundance of solar radiation, making Concentrated Solar Thermal Technologies an economical option to complement, if not replace, fossil fuels for various Industrial Applications. Some of the most viable applications are space and water heating/cooling, process heat, water desalination and effluent treatment. When hybridised with biofuels these thermal energy solutions can deliver 24 x 365 renewable energy.
India has great potential for solar industrial process heating and cooling. Recent studies have shown an addressable market potential of 6.5 GW-thermal for CST technologies out of a total of 13 GW thermal technical potential for industrial applications requiring heat of temperature up to 300°C[1]. Higher temperature applications in industry sectors such as cement, steel and chemical production add further to this potential.
Sunrise CSP’s Big Dish solar concentrator, developed in collaboration with the Australian National University, is a modular 400kWthermal CST platform capable of delivering the steam requirements for the industry at temperatures currently ranging from 150°C to 600°C and pressures up to 160 bar, with new heat transfer fluids lifting temperatures to 800°C planned. The Big Dish is specifically designed for local manufacture and its modularity supports staged and scalable solar field deployment that enables socio-economically appropriate solutions spanning factory-scale to national utility-scale with a Levelized Cost of Steam (LCoS) 14% - 25% lower than fossil fuel alternatives in India.
Intelligent Prediction of Alarm Response Time in Modular and Data-Centric Transmission Grid Operation
Full text linkThis paper presents the theory and implementation of techniques to predict the time available for the Control Center personnel of transmission and distribution system operators to respond to an alarming event related to a grid asset. The described techniques include trendline, linear regression, value-at-risk and k-means classification-based prediction and are implemented to support decision-making even with poor quality SCADA data. These techniques have already been deployed in a modular transmission control center alarming and logging system and can be applied for a variety of assets in power systems as well as in other utilities and process industries
Preface: Future Power Grids Conference 2025
Full text linkOur event reliably addresses the key challenges in power grids and serves as a comprehensive platform for personal exchange at a professional level among all relevant stakeholders every year.
The rapid pace of developments and necessary adjustments in our infrastructure is also reflected in our daily work. For us, one thing is clear: there is no way forward without open and more intensive collaboration between grid operators, manufacturers, regulators, and academia. Practical and scalable solutions are essential to efficiently integrate the growing share of renewable electricity into the overall energy system.
The 2025 conference focused on crucial topics such as the structure of the future energy system from the perspective of power grids, current issues in system stability and grid operation, innovative technologies for secure grid management, the digitalization of the energy system, and the latest developments and innovations in the energy sector.
We firmly believe that we can all contribute significantly to accelerating the transformation and expansion of our energy infrastructure. These conference proceedings play a crucial role in documenting the insights and innovations presented at the event. They serve as a comprehensive record of the discussions, showcasing the latest research, developments, and practical solutions shared by experts across various fields. By publishing these proceedings, we ensure that the valuable knowledge exchanged during the conference reaches a wider audience, contributing to the ongoing dialogue and collaboration necessary to tackle the challenges faced by the power grid sector. This documentation not only highlights the key results from the conference but also serves as a reference point for future work and a foundation for further collaboration between grid operators, manufacturers, regulators, and academia