Integrated topology optimisation of multi-energy networks

Multi-carrier hybrid energy distribution net- works provide flexibility in case of network malfunctions, energy shortages and price fluctuations through energy conversion and storage. Therefore hybrid networks can cope with large-scale integration of distributed and intermittent renewable energy sources. In this article an optimisation approach is proposed which determines the optimal topology of hybrid networks

Voltage rectification effects in mesoscopic superconducting triangles: experiment and modelling

The interaction of externally applied currents with persistent currents induced by magnetic field in a mesoscopic triangle is investigated. As a consequence of the superposition of these currents, clear voltage rectification effects are observed. We demonstrate that the amplitude of the rectified signal strongly depends on the configurations of the current leads with the lowest signal obtained when the contacts are aligned along a median of the triangle. When the contacts are aligned off-centered compared to the geometrical center, the voltage response shows oscillations as a function of the applied field, whose sign can be controlled by shifting the contacts. These results are in full agreement with theoretical predictions for an analogous system consisting of a closed loop with a finite number of identical Josephson junctions.Comment: 5 pages, 4 figures, published in Phys. Rev.

The nature of Ordovician limestone-marl alternations in the Oslo-Asker District (Norway):witnesses of primary glacio-eustasy or diagenetic rhythms?

Ordovician limestone-marl alternations in the Oslo-Asker District have been interpreted as signaling glacio-eustatic lowstands, which would support a prolonged “Early Palaeozoic Icehouse”. However, these rhythmites could alternatively reflect differential diagenesis, without sedimentary trigger. Here, we test both hypotheses through one Darriwilian and three Katian sections. Our methodology consists of a bed-by-bed analysis of palynological (chitinozoan) and geochemical (XRF) data, to evaluate whether the limestone/marl couplets reflect an original cyclic signal. The results reveal similar palynomorph assemblages in limestones and marls. Exceptions, which could be interpreted as reflecting palaeoclimatological fluctuations, exist at the species level: Ancyrochitina bornholmensis seems to be more abundant in the marl samples from the lower Frognerkilen Formation on Nakkholmen Island. However, these rare cases where chitinozoans differ between limestone/marl facies are deemed insufficient for the identification of original cyclicity. The geochemical data show a near-perfect correlation between insoluble elements in the limestone and the marls, which indicates a similar composition of the potential precursor sediment, also in the Frognerkilen Formation. This is consistent with the palynological data. Although an original cyclic pattern could still be recorded by other, uninvestigated parameters, our palaeontological and geochemical data combined do not support the presence of such a signal

Design of an experimental set-up to determine the influence of corrosion on heat transfer

In the exploitation of geothermal energy, heat exchangers are essential to distribute heat to energy conversion systems (e.g. organic Rankine cycles) or district heating networks. The geothermal brine found in Belgium however has a high temperature and a high salinity which makes it extremely corrosive. In such environments, the classic solution is to construct a heat exchanger with a highly corrosion resistant metal such as titanium or nickel. However, since these metals are very expensive, alternatives are investigated. One such alternative is using heat exchangers made of less corrosion resistant materials, but where detailed information about the corrosion process is available. This information is then used during design and for predictive maintenance. An experimental set-up to determine the corrosion rate and the influence of corrosion on the heat transfer is designed.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

Mixed-integer linear program for an optimal hybrid energy network topology

Existing networks do not have the quantitative and qualitative capacity to facilitate the transition towards distributed renewable energy sources. Irregular production of energy over time at different locations will alter the current patters of energy flow, necessitating the implementation of short- and long-term changes in the energy distribution network. To determine the optimal topology of a future multi-carrier hybrid energy distribution network an optimization model is currently under development

Towards an optimal topology for hybrid energy networks

Existing networks do not have the quantitative and qualitative capacity to facilitate the transition towards distributed renewable energy sources. Irregular production of energy over time at different locations will alter the current patters of energy flow, necessitating the implementation of short- and long-term changes in the energy distribution network. To determine the optimal topology of a future multi-carrier hybrid energy distribution network an optimization model is currently under development

Towards an optimal topology for hybrid energy networks

Existing networks do not have the quantitative and qualitative capacity to facilitate the transition towards distributed renewable energy sources. Irregular production of energy over time at different locations will alter the current patters of energy flow, necessitating the implementation of short- and long-term changes in the energy distribution network. To determine the optimal topology of a future multi-carrier hybrid energy distribution network an optimization model is currently under development

Phase slips in mesoscopic superconducting triangles

peer reviewedVoltage-current (V(I)) characteristics are investigated in the superconducting state of an equilateral triangle of 2.2 mu m(2) area. Several steps in the V(I) curves indicate the presence of phase slip centers in the triangle. The field dependence of these steps follows the Little-Parks oscillations of the phase boundary, associated with the change of vorticity. The influence of the contacts manifests itself as an excess voltage and a negative differential resistance. In addition we show that the position of the current contacts modify the superconducting phase boundary measurements. (C) 2008 Elsevier B.V. All rights reserved