Open Access

Wärme‐ und Kältespeicher von Gebäuden beruhen auf verschiedenen Konzepten der Wärmeübertragung. Bei thermischen Hybridspeichern befindet sich das Phasen-wechselmaterial (PCM) makroverkapselt in PCM‐Objekten, die im Speicherbehälter positioniert sind und vom Wärmeträgerfluid umströmt werden. Die experimentellen Untersuchungen widmen sich den Belade‐ und Entladeeigenschaften des in Kugeln makroverkapselten PCM. Es wird gezeigt, dass die spezifische Wärmeübertragungs-leistung eines Hybridspeichers unmittelbar von der Größe der Kugeln als auch von der spezifischen Wärmeleitfähigkeit des PCM abhängt.

Die Bundesregierung hat sich verpflichtet, die Treibhausgasemissionen in den nächsten Jahren stark zu senken. Potentiale hierfür werden besonders im Gebäudesektor gesehen, da dieser einen hohen Anteil des Endenergieverbrauchs verursacht. Bisher lagen für den Gebäudetypus der „Theaterspielstätte“ im Gegensatz zu anderen Gebäudetypologien weder energetische Kennwerte noch Daten zum Raumkomfort vor. Im Rahmen einer deutschlandweiten Querschnittserhebung in 13 Theaterspielstätten über den Zeitraum von drei Wochen wurden sowohl Energieverbräuche mittels zerstörungsfrei installierter Messsensoren als auch Daten zum Raumkomfort durch den Einsatz eines Messtorsos auf Nutzerebene sowie einer parallelen Nutzerbefragung erfasst, ausgewertet und analysiert. Anhand dieser Daten wurden charakteristische Kennwerte gebildet und ein Benchmarking erstellt. Darüber hinaus konnte der Energieverbrauch mittels TEK-Tool rechnerisch auf Nutzungszonen und Gewerke verteilt werden, sodass ein Verständnis für die Struktur des Energieverbrauchs in Theaterspielstätten entwickelt wurde, auf Basis dessen die Abschätzung energetischer Einsparpotentiale möglich ist. Außerdem wurde durch ein einjähriges Intensivmonitoring im sanierten Scharoun Theater Wolfsburg exemplarisch das Einsparpotential durch Gebäudesanierungen und Anlagenoptimierungen von Theaterspielstätten messtechnisch erforscht. Die gemessenen Daten wurden dem Energieverbrauch vor der Sanierung sowie den Sanierungszielen gegenübergestellt und ebenso gegenüber den Kennwerten aus der Querschnittserhebung eingeordnet. Die Erkenntnisse über die Nutzungs- und Energieverbrauchsstruktur in Theaterspielstätten können zukünftig angewendet werden, um Energieverbräuche rechnerisch besser ermitteln zu können und um Ansatzpunkte zur Reduzierung des Energieverbrauchs zu identifizieren.

Pelleted biomass has a low, uniform moisture content and can be handled and stored cheaply and safely. Pellets can be made of industrial waste, food waste, agricultural residues, energy crops, and virgin lumber. Despite their many desirable attributes, they cannot compete with fossil fuel sources because the process of densifying the biomass and the price of the raw materials make pellet production costly. Leaves collected from street sweeping are generally discarded in landfills, but they can potentially be valorized as a biofuel if they are pelleted. However, the lignin content in leaves is not high enough to ensure the physical stability of the pellets, so they break easily during storage and transportation. In this study, the use of eucalyptus kraft lignin as an additive in tree-leaf pellet production was studied. Results showed that when 2% lignin is added the abrasion resistance can be increased to an acceptable value. Pellets with added lignin fulfilled all requirements of European standards for certification except for ash content. However, as the raw material has no cost, this method can add value or contribute to financing continued sweeping and is an example of a circular economy scenario.

Grasping and manipulation with anthropomorphic robotic and prosthetic hands presents a scientific challenge regarding mechanical design, sensor system, and control. Apart from the mechanical design of such hands, embedding sensors needed for closed-loop control of grasping tasks remains a hard problem due to limited space and required high level of integration of different components. In this paper we present a scalable design model of artificial fingers, which combines mechanical design and embedded electronics with a sophisticated multi-modal sensor system consisting of sensors for sensing normal and shear force, distance, acceleration, temperature, and joint angles. The design is fully parametric, allowing automated scaling of the fingers to arbitrary dimensions in the human hand spectrum. To this end, the electronic parts are composed of interchangeable modules that facilitate the echanical scaling of the fingers and are fully enclosed by the mechanical parts of the finger. The resulting design model allows deriving freely scalable and multimodally sensorised fingers for robotic and prosthetic hands. Four physical demonstrators are assembled and tested to evaluate the approach.

The ‘Energy Crisis’ has become the talk of the town in pretty much every developing and lower developing countries in today’s world. It is characterized by a state where the country’s locally available energy resources are being depleted and it is dependent on imported fuel. The problem is considered as although not parallel, but a descendant of the food crisis in terms of the seriousness of the problems in developing nations essentially in Sub-Saharan Africa (SSA). Ethiopia is one such country which nevertheless going through a rapid scale of development (nearly 11 % annual growth rate as of 2017 according to the World Bank) and also is endowed with an enormous amount of natural resources such as hydro, wind, solar, geothermal energy potential. The Ethiopian power sector is heavily dependent on the country’s hydropower resources. However, it needs to diversify its energy sector and integrate new and other renewable energy sources because, in the longer term, its extreme hydropower dependence may put its power sector vulnerable to natural risks like droughts which are very likely scenarios due to the climate change. Since the lack of access to modern forms of energy services left no choice for the Ethiopians than to continue their traditional biomass use, and it results in unsustainable environmental harm with deforestation, soil erosion, and many others. To address this issue, Ethiopia is taking necessary steps towards climate-friendly industrialization of the economy. In order to understand this transition, a socio-technical analysis of Ethiopian ambitious transformation from an agrarian society to a climate resilient green society has been presented in this paper. An analytical framework will be formulated as a prerequisite for the study by introducing the theory of Multilevel Perspective (MLP). This theory enables the understanding of three different levels of socio-technical environment namely niches, regime, and landscape in which the respective actors interact with each other to facilitate the process of transition. As a part of laying the groundwork, this thorough analysis constitutes all the country’s energy-related activities and associated energy demands, conversion technologies, current fuel mix, primary energy resources, and energy policies in the Ethiopian energy system. The LEAP analysis results from Mr. Md Alam Mondal and group are summarized to obtain an understanding of the country’s total energy demand scenarios. Consequently, the actors from each socio-technical level have been identified in the context of Ethiopia and their dynamics of interaction have been explained in order to understand the process of energy system transition of Ethiopia in the direction of diversification of its energy system and hence result in the expansion of new renewable energy sector. Most importantly the assessment suggests that the transition process is majorly driven by top-down forces and intra-level reconfiguration of regime actors. There are no bottom-up forces acting as only a little research and development work takes place in the country to develop new radical changes/technological niches. A developing country like Ethiopia has undoubtedly a bright future ahead with all systems in place and the nature-gifted natural resource potential. The ambitious goals set by the country and the international help from developed allies are definitely working in tandem to ensure their accomplishment. With its guiding vision towards development and the global climate change movement, Ethiopia surely has the potential to lead by example.