A multi-layer agent-based model for the analysis of energy distribution networks in urban areas

Significant research contributions and Directives approach the issue of the insertion of renewable-based energy systems on urban territory in order to face with the growing energy needs of citizens. The introduction of such systems gives raise to installers to both satisfy their energy demands and distribute eventual energy excesses to close neighbours. This paper presents a multi-layer agent-based computational model that simulates multiple event of the network of the energy distribution occurring within urban areas. The model runs on the NetLogo platform and aims at elaborating the most suitable strategy when dealing with the design of a network of energy distribution. Experimental data are discussed on the basis of two main scenarios within an operating period of 24 hours. Scenarios consider both the variation of the percentages of installers of renewable-based energy systems and the distance along which energy exchanges occur.Comment: 22 pages, 15 figure

Appearance of quasiperiodicity within a period doubling route to chaos of a swaying thermal plume

The birth, evolution and disappearance of quasiperiodic dynamics in buoyancy-driven flow arising from an enclosed horizontal cylinder are analysed here, by numerical means, in the limit of the 2D approximation. The governing equations are solved on orthogonal Cartesian grids, giving special treatment to the internal, non-aligned boundaries. Thanks to the adoption of a high level of re finement of the Rayleigh number range, quasiperiodicity was observed to emerge from a periodic limit cycle (P1), and to turn into its omologous orbit with doubled period (P2), eventually evolving into a classical period-doubling route to chaos, for further increases of the Rayleigh number. The present study gives a deeper insight to what appears to be an imperfect period doubling bifurcation through a quasiperiodic T2-torus. The approach used is based on the classical tools for time series analysis. The distribution of the power spectral densities is used to search for and characterise the existence of relations between the frequencies of the P1, T2 and P2 dynamics. The topology of the orbits, as well as their evolution within the quasiperiodic window, are analysed with the aid of phase space representation and Poincar è maps

Heat transfer along the route to chaos of a swaying thermal plume

Detailed analyses have been recently reported on the low order dynamics of a thermal plume arising from a horizontal cylindrical heat source concentric: to an air-\ufb01lled isothermally cooled square enclosure, together with those of the related \ufb02ow structures, in the limit of the 2D approximation. In particular. within the range of O < Ra < 3 RaL-T, With Ram corresponding to the loss of stability of the stationary buoyant plume, the entire evolution from a periodic limit cycle (P1) to the birth of chaos through a period\ubbdoubling cascade has been fullyexplored. With this respect, special attention has been given to the window of quasiperiodic dynamics onto a T;-torus that is observed to separate the monoperiodic dynamics from the biperiodic dynamics onto a P1 and a Pg-liniit cycle, respectively. The results of these analyses hint at the bimodal nature of the overall dynamics. in general, and of the subharmonic cascade, in particular, which are still under investigation. Although relevant on a dynamical perspective, a with a main re\ufb02ection on the laminar-turbulent transition, the observed oscillations appear to be characterised by comparable amplitudes and to be determined by similar evolutions of the \ufb02ow pattern evolutions, so that their role on the overall heat transfer rate is expected to be marginal. Vi/'ithin this frame, the present study aims at reporting the in\ufb02uence played by the observed dynamics of the thermal plume and of the [low structures on the global heat transferrate. In particular, the aim is the assessment of the correlation between the Rayleigh number and the average Nusselt number on the cylinder surface, as well as the effect on the latter of the observed series of bifurcations

Bifurcations of Natural Convection Flows from an Enclosed Cylindrical Heat Source

A numerical analysis of transitional natural convection from a confined thermal source is presented. The system considered is an air-filled, square-sectioned 2D enclosure containing a horizontal heated cylinder. The resulting flow is investigated with respect to the variation of the Rayleigh number, for three values of the aspect ratio A. The first bifurcation of the low-Ra fixed-point solution is tracked for each A-value. Chaotic flow features are detailed for the case A = 2.5. The supercritical behaviour of the system is investigated using nonlinear analysis tools and phase-space representations, and the effect of the flow on heat transfer is discussed

Towards the Complete Self-Sufficiency of a nZEBs microgrid by Photovoltaic Generators and Heat Pumps: Methods and Applications

The present paper proposes a multidisciplinary procedure to correctly design a microgrid of all-electric nZEBs (nearly Zero Energy Buildings) from both electrical and thermal points of view. The procedure is suitable for new buildings supplied by local renewables, without the use of fossil fuel and with zero emissions. First, the thermal demand of each single nZEB is assessed, as a function of the installation site, building layout and physics, and material composing the envelope. Thanks to heat pumps, the thermal demand is transformed in electric load. Thus, the total electric consumption profiles, which include user's appliances and heating/cooling, are studied and compared with Photovoltaic (PV) generation supported by electrochemical storages. Both PV and batteries are simulated thanks to appropriate models. Regarding the PV production assessment, the present work proposes an improvement with respect to the use of traditional models, and it is based on experimental results on PV generators of recent production. The design methodology is applied to a real case of “energy community” composed of three nZEB units, that will be built in the campus of Politecnico di Torino, available to students and staff. The three units share PV production and storage capacity to reach the complete grid-independence

Improvement of self-sufficiency for an innovative nearly zero energy building by photovoltaic generators

In the present work, a case study of an innovative nearly Zero Energy Building (nZEB) for academic purposes is investigated. In particular, its primary energy vector is electrical, i.e. a Photovoltaic (PV) generator is coupled with storage units and supplies the electrical loads and the thermal demand, which is converted into electrical by heat pumps. The system is designed to maximize the self-sufficiency and minimize the absorption from the grid. Moreover, the nZEB is equipped with sensors that are oriented to smart metering in order to monitor the energy exchange between the rooms of the building. An energy simulation is performed on a yearly basis, evaluating the size of the batteries, to reach the optimal compromise between benefits, in terms of self-sufficiency, and costs

Local Production and Storage in Positive Energy Districts: The Energy Sharing Perspective

In response to the Positive Energy District transition, this paper proposes an energy tool for the modeling of energy sharing configurations among buildings equipped with energy production systems and distributive storages. The model is targeted for urban planners and energy policymakers and gives insights into the role of buildings in fostering the achievement of net-zero energy balances in districts when virtual or physical peer-to-peer configurations are established in the area. A real urban district is considered as a case study and the energy performances are measured against properly defined Key Performance Indicators. Results confirm the strategic role played by energy sharing among buildings in achieving self-sufficient and carbon-neutral areas. In particular, the insertion of storages allows not only for higher self-sufficiency of the area (by facilitating the coupling of production and demand) but also for higher distribution rates among buildings. However, photovoltaic insertion and storages should be appropriately balanced since it has been observed that at increasing the number of production and storage systems, the distribution is reduced in favor of autonomy, thus limiting the usefulness of an interconnected local distribution grid

Nuovi approcci per godere la musica d’oggi. Un progetto didattico

This article presents the first results of the project “Nuovi approcci per godere la musica d’oggi” (New approaches to enjoying today’s music), developed within the SagGEM workgroup with the collaboration of composer Alessandro Solbiati. The aim is to fine-tune coherent, well-planned didactic modules based on the 20th and 21st-century repertory, through very close interaction between the acquired knowledge and tools of musicology and music pedagogy, and field work based on direct interaction with students. In particular, the article reconstructs didactic activities carried out on the compositions of György Ligeti, Poème symphonique pour 100 métronomes and Lux aeterna. These pieces belong to the early maturity of the Hungarian musician, and require that listeners develop new perceptual strategies, since they are conceived and built around music parameters that used to be regarded as secondary, such as ‘texture’, timbre and sound gesture

Self-Consumption and Self-Sufficiency in Photovoltaic Systems: Effect of Grid Limitation and Storage Installation

This paper presents a methodology to maximize the self-sufficiency or cost-effectiveness of grid-connected prosumers by optimizing the sizes of photovoltaic (PV) systems and electrochemical batteries. In the optimal sizing procedure, a limitation on the maximum injection in the grid can affect the energy flows, the economic effectiveness of the investments, and thus the sizing results. After the explanation of the procedure, a case study is presented, and a parametric analysis of the effect of possible injection limits is shown. The procedure is applied to size plants for an Italian domestic prosumer, whose electric load profile was measured for a year. A software program developed using the proposed methodology is also briefly presented. It is used for both research and educational purposes, both in laboratory classes and in remote lesson