Bei den Phosphaten, Arsenaten und Vanadaten der Seltenen Erden treten zwei Strukturtypen auf. Die überwiegende Zahl kristallisiert mit der Struktur des Zirkons. Eine Reihe von Verbindungen mit den größeren Ionen der Seltenen Erden zeigt die Struktur des Huttonits bzw. Monazits. Beim TbPO4 konnten beide Strukturtypen nachgewiesen werden. Die Abmessungen der Elementarzellen für die Verbindungen mit Zirkonstruktur werden mitgeteilt. Der Verlauf der Gitterkonstanten und Elementarzellenvolumina zeigt bei den Arsenaten und Vanadaten in Abhängigkeit von der Ordnungszahl der Seltenen Erden keine Unstetigkeit beim Gadolinium. Auch ScAsO4 und ScVO4 kristallisieren wie das schon länger bekannte ScPO4 mit Zirkonstruktur. Beim BiPO4 existiert neben einer Niedertemperaturmodifikation mit der Struktur des Huttonits, die auch für BiAsO4 beobachtet wird, eine weitere, bisher unbekannte Modifikation.

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The expansion of fluctuating renewable energy sources leads to an increasing impact of weather-related uncertainties on future decentralized energy systems. Stochastic modeling techniques enable an adequate consideration of the uncertainties and provide support for both investment and operating decisions in such systems. In this paper, we consider a residential quarter using photovoltaic (PV) systems in combination with multi-stage air-water heat pumps and heat storage units for space heating and domestic hot water. We model the investment and operating problem of the quarter's energy system as two-stage stochastic mixed-integer linear program (SMILP) and optimize the thermal storage units. In order to keep the resulting stochastic, large-scale program computationally feasible, the problem is decomposed in combination with a derivative-free optimization (DFO). The subproblems are solved in parallel on high-performance computing (HPC) systems. Our approach is integrated in that it comprises three subsystems: generation of consistent ensembles of the required input data by a Markov process, transformation into sets of energy demand and supply profiles and the actual stochastic optimization. An analysis of the scalability and comparison with a state-of-the-art dual decomposition method using Lagrange relaxation and a conic bundle algorithm shows a good performance of our approach for the considered problem type. A comparison of the effective gain of modeling the quarter as stochastic program with the resulting computational expenses justifies the approach. Moreover, our results show that heat storage units in such systems are generally larger when uncertainties are considered, i.e. stochastic optimization can help to avoid insufficient setup decisions. Furthermore, we find that the storage is more profitable for domestic hot water than for space heating.

Many countries have adopted schemes to promote investments into renewable energy sources resulting, amongst others, in a high penetration of solar PV energy. The system integration of the increasing amount of variable electricity generation is therefore a highly important task. This paper focuses on a residential quarter with PV systems and explores how heat pumps and thermal and electrical storages can help to integrate the PV generation through self-consumption. However, self-consumption and PV integration are not only affected by technologies but also by pricing mechanisms. This paper therefore analyses the impact of different tariffs on the investment and operation decisions in a residential quarter and its interaction with the external grid. The considered tariffs include a standard fixed perkilowatt-hour price, a dynamic pricing scheme and a capacity pricing scheme. To account for the interdependent uncertainties of energy supply, demand and electricity prices, we use a module-based framework including a Markov process and a two-stage stochastic mixedinteger program. Analysing a residential quarter in Southern Germany as a case study, we find that the integration of a PV system is economically advantageous for all considered tariffs. The self-consumption rate varies between 58 − 75%. The largest PV system is built when dynamic prices are applied. However, the peak load from the external grid increases by a factor of two under this tariff without any incentive for reduction. In contrast, capacity pricing results in a reduction of the peak load by up to 35%.

Inhaltsiibersicht I n den Systemen MIIO/XIVO, (MI1 = Sr, Ba; XIv = Zr, Hf) existieren neben den Metaverbindungen basenreichere Verbindungen des Typs M:IXIVO, mit tetragonaler K,NiF,-Struktur. Eingehende Untersuchungen in den Systemen Li,O/X1vO, (XIV = Zr, Hf) fiihrten zur Darstellung und Charakterisierung der neuen Verbindungstypen Li4XIv0, und L&XIVO,. Tho, bildet mit Erdalkali-und Alkalioxiden nur Metaverbindungen, tritt jedoch mit Li,O uberhaupt nicht in Reaktion. Zwischen Na,ThO, und Li,ZrO, besteht nach den Rontgenpulverdiagrammen eine enge strukturelle Beziehung. SummaryIn the systems MIIO-XIVO, with MI1 = Sr, Ba; XIv = Zr, Hf besides meta compounds more basic compounds of the typeM:IXIV04, having the tetragonal K,NiF, structure, exist. Investigations on the systems Li,O-XxIVO, (XI"= Zr, Hf) resulted in the preparation and characterisation of the new compound types Li4XIV04 arid Li,XWO,.Tho, gives with alkaline-earth and alkali metal oxides only meta compounds, however. no reaction with Li,O. A close structural relation between Na,ThO, and Li,ZrO, exists according to their X-ray powder diagrams. EinleitungI m Rahmen der Untersuchungen uber zahlreiche Oxidsysteme durch SCHOLDER und Mitarbeiter 2, wurden auch die Systeme ZrO,/MTIO bzw. M i 0 (MI' = Ba, Sr; MI = Li, Na), HfO,/M1'O bzw. Mi0 (MI1 = Ba, Sr; MI = Li) und ThO,/M"O bzw. M i 0 (MI' = Ba; MI = Na) eingehend mit dem besonderen Ziel der Darstellung und Charakterisierung basenreicher Verbindungen bearbeitet .