103 research outputs found
Future Challenges in Heterogeneous Catalysis: Understanding Catalysts under Dynamic Reaction Conditions
In the future, (electro-)chemical catalysts will have to be more tolerant towards a varying supply of energy and raw materials. This is mainly due to the fluctuating nature of renewable energies. For example, power-to-chemical processes require a shift from steady-state operation towards operation under dynamic reaction conditions. This brings along a number of demands for the design of both catalysts and reactors, because it is well-known that the structure of catalysts is very dynamic. However, in-depth studies of catalysts and catalytic reactors under such transient conditions have only started recently. This requires studies and advances in the fields of 1) operando spectroscopy including time-resolved methods, 2) theory with predictive quality, 3) kinetic modelling, 4) design of catalysts by appropriate preparation concepts, and 5) novel/modular reactor designs. An intensive exchange between these scientific disciplines will enable a substantial gain of fundamental knowledge which is urgently required. This concept article highlights recent developments, challenges, and future directions for understanding catalysts under dynamic reaction conditions
Mindergie: A pervasive learning game for pro-environmental behaviour at the workplace
This chapter reports about a pervasive learning game to increase the environmental awareness and pro-environmental behaviour at the workplace. Based on a discussion of the theoretical background and related work we introduce the game design and game elements. Results of a formative evaluation study are presented and discussed. Results show that incentive mechanisms are less important than challenging game components that involve employees in proposing solutions for energy conservation at the workplace. Conclusions are drawn for future games and energy conservation activities at the workplace.This project has been partially funded by a SURFnet innovation grant for sustainable ICT solutions and partially by the Welten Institute – Research Centre for Learning, Teaching and Technology of the Open University of the Netherlands
Grid impact of a net zero energy building with BiPV using different energy mangament strategies
A net-zero energy office building with Building-integrated photovoltaics (BiPV), a heat pump with cooling functionality and TABS as a heat distribution system is simulated in dynamic thermohydraulic simulations in Dymola. The focus of the evaluation is the electricity exchange with the grid. The temporal mismatch between local electricity production and electricity consumption is evaluated using established indicators such as the autonomy and self-consumption. Moreover, it is analyzed during which times electricity is consumed from the grid, and how high the fraction of Wind and PV in the energy mix is during the time of consumption. The latter is quantitatively expressed using the Grid Support Coefficients GSCabs and GSCrel proposed by the authors. HVAC operation accounts for roughly 43% of the total electricity consumption of the considered building. With a conventional HVAC control concept based on heating and cooling curves, an annual autonomy rate of 42% and a self-consumption rate of 43% are achieved. In an alternative control scheme, the trajectory of heat and cold delivery to the zones is altered such that the self-consumption of the locally produced electricity is maximized. The remaining electricity demand for HVAC operation, which has to be covered from the public grid, is shifted to times of a high availability of Wind and PV power in the energy system. With this energy management scheme, the autonomy and the selfconsumption rate are increased to 50% and 53%, respectively. The fraction of Renewables in the electricity consumed from the public grid is increased by 15% (relative). Thermal comfort in the offices is only moderately affected by the shifting of the heating and cooling loads
Numerical study on load shifting strategies for the heating and cooling of an office building considering variable grid conditions
In this simulation study, the load shifting potential of a plus-energy office building with local PV generation, a ground-coupled heat pump and TABS using the heating and cooling system is discussed. The evaluated load shifting strategy uses the building mass as a thermal storage by rescheduling the delivery of thermal energy to the zones, based on the availability of local PV generation and the fraction of wind and PV in the public grid. It is implemented as a co-simulation of Dymola (for simulation of the full system) and Python (for the load shifting algorithm and test of comfort criteria using a functional mock-up unit (FMU) of the building). Using the presented strategy, self-consumption and autonomy of the locally produced electricity can be increased by 3%abs and the grid support coefficient GSCrel of the heat pump can be increased from -11 to +58 while maintaining thermal comfort. Between spring and autumn, the load shifting potential of the heat pump is limited due to low heating and cooling demand. It can be increased by a factor of 2-3 if the comfort requirements are relayed by a soft constraint. Load shifting decreases the efficiency of the heating and cooling system by 2.8%
Who is taking MOOCs for teachers' professional development on the use of ICT?: A cross-sectional study from Spain
Research on the use of Massive Open Online Courses (MOOCs) for teacher professional development (TPD) and the characteristics of their participants is scarce. This article presents a case of a MOOC initiative supported by the Spanish Ministry of Education aiming at teachers’ professional development on the use of ICT for teaching and learning. The analysis is focused on (a) the sociodemographic and school characteristics of the teachers participating in MOOCs; (b) their experience and beliefs about lifelong learning; and (c) the relevance of MOOCs for their work. By contrasting the characteristics of the participants in this initiative with the characteristics of the whole population of teachers in Spain, and a sample of Spanish participants in MOOCs not aimed at TPD, the article sheds light on the specificities of the teachers who use this way of TPD. The results have implications for the design of programmes aimed to develop MOOCs for TPD
Revisiting the synthesis and elucidating the structure of potassium Cyclopentadienyldicarbonylruthenate, K[CpRu(CO)(2)].
Known procedures for the synthesis of K[CpRu-(CO)(2)] (KRp) via reductive cleavage of the ruthenium dimer Rp(2) were found to be inconsistent and have thus been revisited, and a revised protocol using K[HB(sec-Bu)(3)] (K-Selectride) as the reducing agent is now reported that gives yellow KRp in crystalline form in around 40% yield. The structure of KRp THF has been determined by X-ray diffraction, representing the first crystallographic characterization of an Rp(-) salt. Inevitably the reductive cleavage of Rp(2) also gives a poorly soluble black solid as an additional product, which has now been analyzed by a variety of methods, including C-13 MAS NMR spectroscopy using (CO)-C-13-labeled material. The black solid has been identified as a polymeric Cp/Ru/CO compound with both bridging and terminal CO ligands in a 3:1 ratio. The present report may stimulate the use of the [CpRu(CO)(2)](-) (Rp(-)) anion, which has been barely exploited as yet in comparison to its popular congener [CpFe(CO)(2)](-) (Fp(-))
Does project focus influence challenges and opportunities of open online education?:A sub-group analysis of group-concept mapping data
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