Economic feasibility of flow batteries in grid-scale applications

Due to their properties, the most suitable application for flow batteries currently is a bulk energy storage. This thesis investigates the economic feasibility of the technology in terms of monetary profitability in the appropriate business cases, namely employment in electricity markets and in isolated island systems with the high share of renewable generation. This thesis calculates the flow batteries annual life cycle costs and compares them with the potential revenues from participation in the Finnish electricity markets and operation in isolated power systems of the Faroe Islands and the island of Graciosa. The flow batteries exploitation in the Finnish electricity markets is not profitable – they collect 43-60% of their costs in the most promising application. The island cases represent a more viable option due to the high fuel costs of the thermal plants that the batteries and renewable sources substitute or decrease their share. However, the revenue and subsequent profitability highly depend on the volatile fuel prices

Kantharoi in bucchero dalla regione pontica

Tre kantharoi in bucchero etrusco sono stati di recente rinvenuti nella regione pontica settentrionale rispettivamente sull’isola di Berezan, corrispondente all’antica Borysthenes, e a Taganrog, corrispondente all’antica Kremnoi. I due centri, che sono entrambi fondazioni milesie del VII sec. a.C., hanno restituito vasellame greco databile dal VII sec. a.C. in avanti. I tre kantharoi sono gli unici reperti in bucchero etrusco al momento noti dalla costa settentrionale del Mar Nero e dal Mare di Azov. È presumibile che Mileto, città madre di molte colonie nella regione pontica e sito di provenienza della più vasta quantità di bucchero etrusco restituita dal Mediterraneo orientale, possa aver avuto un ruolo attivo nella redistribuzione di questo vasellame nell’area nord pontica

Методы прочностных стендовых испытаний моделей и элементов конструкций ракетно-космической техники

The paper considers the methodological support and evaluation of operation reliability of rocket and space equipment using the inlet lips of ramjet engine (RJE) as an example. The successful solution to these issues is largely defined by the optimal selection of materials - special high-temperature alloys and structural ceramics.The methods for modeling the loading conditions of the inlet lips in a high-temperature gas flow are developed from the approaches that ensure the similarity of the external effect on the structural element and equivalency of damage to the material under the model and full-scale conditions. The process of modeling of equivalent states of the material of extreme thermally-loaded zones (models) is realized in the form of specialized procedures on a gas-dynamic test bench to investigate the performance of materials and structural elements in high-temperature gas flows with variable thermo-dynamic parameters.The approaches are based on the classical theories of similarity and different dimensions, which were changed and adapted to investigate the thermal cyclic strength of materials and damageability of structural elements under loading in high-speed high-temperature gas flows.The developed procedures and experimental facilities allowed one to carry out a set of investigations on the functional characteristics, as well as obtain the system of properties for three materials at extremely high temperatures. It is demonstrated that the realized methods provide the required information for the development of structural elements operating under conditions of aerodynamic heating.The results of bench tests are presented in compliance with the data obtained in the numerical analysis of the implemented conditions of thermal loading on a gas-dynamic test bench, as well as the calculations of thermal and stress states of the inlet lips made of various materials. Based on the data of experimental and analytical generalization of the boundary heat-exchange conditions, the numerical modeling of the dependence of TSSS of the models on the geometric parameters and physical properties of the material is performed under test bench conditions. It is implied that such comparative tests should be performed using the models of similar shape and the same geometric dimensions since their difference affects the stress state of structural elements significantly.На примере кромок воздухозаборников прямоточного воздушно-реактивного двигателя (ПВРД) рассматриваются вопросы методологического обеспечения и оценки эксплуатационной надежности изделий ракетно-космической техники. Успешное решение этой проблемы во многом определяется оптимальным выбором материалов соответствующих классов – специальных жаропрочных сплавов и конструкционной керамики.Разработаны методы моделирования условий нагружения кромок воздухозаборников в высокотемпературном газовом потоке с использованием подходов, обеспечивающих подобие внешнего воздействия на конструкционный элемент и эквивалентность процессов повреждения материала в модельных и натурных условиях. Моделирование эквивалентных состояний материала экстремально термонагруженных зон макетов реализовано в виде специализированных методик с использованием возможностей комплекса газодинамических стендов для исследования работоспособности материалов и элементов конструкций в высокотемпературных газовых потоках переменных термодинамических параметров.Фундаментальной базой этих подходов являются классические теории подобия и размерностей, основные положения которых трансформированы и адаптированы применительно к задачам исследования термоциклической прочности материалов и повреждаемости элементов конструкций при нагружении в высокоскоростных высокотемпературных газовых потоках.Разработанные методики и экспериментальные средства позволили провести цикл исследований функциональных характеристик, получение комплекса свойств трех видов материалов при экстремально высоких температурах, соответствующих эксплуатационным. Показано, что реализованные методы обеспечивают получение необходимой информации для отработки технологии создания элементов конструкций, работающих в условиях аэродинамического нагрева.Результаты стендовых испытаний макетов представлены в связи с информацией, полученной в процессе численного анализа реализованных условий термического нагружения на газодинамическом стенде и расчетов теплового и напряженного состояния кромок макетов из различных материалов. По данным экспериментального и аналитического обобщения граничных условий теплообмена в стендовых условиях проведено численное моделирование зависимости ТНДС макетов от геометрических параметров и физических свойств исследованных материалов. Показано, что такие сравнительные испытания необходимо проводить на моделях одинаковой формы и одних геометрических размеров, так как их отличие существенно влияет на напряженное состояние конструкционных элементо

Economic feasibility of flow batteries in grid-scale applications

Due to their properties, the most suitable application for flow batteries currently is a bulk energy storage. This paper investigates the economic feasibility of the technology in terms of monetary profitability in the appropriate business cases, namely employment in energy markets and in isolated island systems with the high share of renewable generation. We calculate the flow batteries life cycle costs and compare them with the potential revenues from participation in the Finnish energy markets and operation in isolated power systems of the Faroe Islands and the island of Graciosa. We find that the flow batteries exploitation in the Finnish market is not profitable - they collect 43-60% of their costs in the most promising application. The island cases represent a more viable option due to the high fuel costs of the thermal plants that the batteries and renewable sources substitute or decrease their share. However, the revenue and subsequent profitability highly depend on the volatile fuel prices.Peer reviewe