Articoli di riviste: "Collective heating"

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Cabezas-Rivière, Enzo, Thomas Recht, Aline Barlet, Maxime Robillart, Mathieu Bouville e Patrick Sebastian. "Towards sustainable energy consumption for occupants of buildings with collective heating systems". Journal of Physics: Conference Series 2600, n. 9 (1 novembre 2023): 092019. http://dx.doi.org/10.1088/1742-6596/2600/9/092019.

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Abstract Global warming is forcing us all to reduce our fossil energy consumption. A quantitative survey of people using collective heating in France was conducted to determine whether collective heating hinders energy savings and limits their thermal comfort. The study shows that the existing environment (e.g., heating control devices, access to heating bills) is not suitable for the occupants. Furthermore, the results point out that behaviour is not considered, by occupants, as one of the main energy saving vectors. This is partly due to heating control devices that can be inconvenient to use and thus do not maximize their thermal comfort. Indeed, there is a large difference between the temperature residents want, and the one they get. Our study population reported that rooms are colder than people wish. To achieve sustainable energy savings, efforts should be made to better take into account their comfort while making the technical system more suitable to the occupants, for example, by improving access to and understanding of bills and replacing the current manual control valves with programmable and remotely controllable ones.

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CHIEN, L. H., A. SERGEEV, N. VAGIDOV, V. MITIN e S. BIRNER. "ELECTRON HEATING IN QUANTUM-DOT STRUCTURES WITH COLLECTIVE POTENTIAL BARRIERS". International Journal of High Speed Electronics and Systems 20, n. 01 (marzo 2011): 143–52. http://dx.doi.org/10.1142/s0129156411006477.

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Here we report our research on quantum-dot structures with collective barriers surrounding groups of quantum dots (planes, clusters etc) and preventing photoelectron capture. Employing Monte-Carlo simulations, we investigate photoelectron kinetics and calculate the photoelectron lifetime as a function of geometrical parameters of the structures, dot occupation, and electric field. Results of our simulations demonstrate that the capture processes are substantially suppressed by the potential barriers and enhanced in strong electric fields. Detailed analysis shows that the effects of the electric field can be explained by electron heating, i.e. field effects become significant, when the shift of the electron temperature due to electron heating reaches the barrier height. Optimized photoelectron kinetics in quantum-dot structures with collective barriers allows for significant improvements in the photoconductive gain, detectivity, and responsivity of photodetectors based on these structures.

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Knatko M.V. e Lapushkin M.N. "Collective processes in thermal ionization on the surface of NaAu-=SUB=-x-=/SUB=- intermetallic compound". Technical Physics 92, n. 9 (2022): 1237. http://dx.doi.org/10.21883/tp.2022.09.54689.87-22.

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A mechanism is proposed for the decomposition of molecular clusters of diethylamine (C2H5)2NH on the surface of the NaAux intermetallic compound with the formation of decomposition products desorbed from the surface, including in the form of ions with m/z from 58 to 197, during heating of the intermetallic compound at a rate of 20 K/s. Exposure of the NaAux surface at a temperature of 320 K in diethylamine vapor leads to the formation of molecular clusters on it. Rapid heating of NaAux at a rate of 20 K/s leads to the decay of clusters, desorption, and ionization of the decay products due to the redistribution of internal energy over the degrees of freedom of the cluster. The study of thermal ionization processes during heating of NaAux at a rate of 20 K/s in the temperature range from 600 to 1000 K made it possible to establish that the surface stoichiometry during heating is quasi-stationary, dehydrogenation and ionization of individual diethylamine molecules occur under equilibrium conditions, while for compounds formed in the process of cluster decay, the conditions are not equilibrium. Keywords: thermal ionization, diethylamine, intermetallics, sodium, gold.

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Vlasov, V. G., V. V. Klimenko, G. K. Matafonov e A. V. Tashchilin. "Collective heating and radiation dynamics of the auroral ionospheric F2-region". Journal of Atmospheric and Terrestrial Physics 54, n. 7-8 (luglio 1992): 995–1005. http://dx.doi.org/10.1016/0021-9169(92)90066-t.

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Ali, Emad, Abdelhamid Ajbar e Bilal Lamrani. "Numerical Investigation of Thermal Energy Storage Systems for Collective Heating of Buildings". Buildings 14, n. 1 (6 gennaio 2024): 141. http://dx.doi.org/10.3390/buildings14010141.

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This study aims to investigate and identify the most effective thermal energy storage (TES) system configuration for the collective heating of buildings. It compares three TES technologies, i.e., sensible, latent, and cascade latent shell and tube storage, and examines their respective performances. A fast and accurate lumped thermal dynamic model to efficiently simulate TES system performances under different operation conditions is developed. The validation of this model’s accuracy is achieved by aligning numerical findings with data from prior experimental studies. Key findings indicated that the latent and cascade latent shell and tube storage systems demonstrate superior thermal energy storage capacities compared to the sensible configuration. Using a single-phase change material (PCM) tank increases the duration of constant thermal power storage by about 50%, and using a cascade PCM tank further enhances this duration by approximately 65% compared to the sensible TES case. Moreover, the study revealed that adjusting the PCM composition within the cascade TES significantly influenced both thermal power storage durations and pumping energy consumption. In summary, the recommended cascade PCM configuration for collective heating of buildings offers a balanced solution, ensuring prolonged stable thermal power production, elevated HTF outlet temperatures, and improved energy efficiency, presenting promising prospects for enhancing TES systems in district heating applications.

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Mikhailov, I. N., T. I. Mikhailova, M. Di Toro, V. Baran e Ch Briançon. "Collective dynamics of nuclear fusion: deformation changes and heating during the fusion". Nuclear Physics A 604, n. 3 (luglio 1996): 358–84. http://dx.doi.org/10.1016/0375-9474(96)00166-2.

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Deng, Weichu, Zhongbing Shi, Peiwan Shi, Feng Zhang, Xin Yu, Zengchen Yang, Min Jiang et al. "Design of the Collective Thomson Scattering System on HL-3 tokamak". EPJ Web of Conferences 313 (2024): 03005. http://dx.doi.org/10.1051/epjconf/202431303005.

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A collective Thomson scattering (CTS) diagnostic system is being developed to measure fastion velocity distribution on HL-3 tokamak. A 140 GHz gyrotron belonging to electron cyclotron resonance heating (ECRH) system would be used to generate probe beam. The scattering spectra among HL-3 parameter ranges are calculated to assess diagnostic feasibility. Scattering signals will be detected by a heterodyne system, which is proposed to optimize diagnostic performance.

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Klimchuk, James A. "Key aspects of coronal heating". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, n. 2042 (28 maggio 2015): 20140256. http://dx.doi.org/10.1098/rsta.2014.0256.

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We highlight 10 key aspects of coronal heating that must be understood before we can consider the problem to be solved. (1) All coronal heating is impulsive. (2) The details of coronal heating matter. (3) The corona is filled with elemental magnetic stands. (4) The corona is densely populated with current sheets. (5) The strands must reconnect to prevent an infinite build-up of stress. (6) Nanoflares repeat with different frequencies. (7) What is the characteristic magnitude of energy release? (8) What causes the collective behaviour responsible for loops? (9) What are the onset conditions for energy release? (10) Chromospheric nanoflares are not a primary source of coronal plasma. Significant progress in solving the coronal heating problem will require coordination of approaches: observational studies, field-aligned hydrodynamic simulations, large-scale and localized three-dimensional magnetohydrodynamic simulations, and possibly also kinetic simulations. There is a unique value to each of these approaches, and the community must strive to coordinate better.

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Poedts, Stefaan, Wolfgang Kerner e Marcel Goossens. "Alfvén-wave heating in resistive MHD". Journal of Plasma Physics 42, n. 1 (agosto 1989): 27–58. http://dx.doi.org/10.1017/s0022377800014173.

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Resonant absorption of Alfvén waves in tokamak plasmas is studied numerically using the linearized equations of resistive magnetohydrodynamics. A numerical code based on a finite-element discretization is used for determining the stationary state of a cylindrical plasma column that is excited by an external periodic driver. The energy dissipation rate in the stationary state is calculated and the dependence of the plasma heating on electrical resistivity, the equilibrium profiles, and the wavenumbers and frequency of the external driver is investigated. Resonant absorption is extremely efficient when the plasma is excited with a frequency near that of a so-called ‘collective mode’. The heating of a plasma by driving it at the frequencies of discrete Alfvén waves is also investigated.

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Van de Putte, Stijn, Marijke Steeman e Arnold Janssens. "The Building Energy Performance Gap in Multifamily Buildings: A Detailed Case Study Analysis of the Energy Demand and Collective Heating System". Sustainability 17, n. 1 (1 gennaio 2025): 252. https://doi.org/10.3390/su17010252.

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The building energy performance gap, resulting from a discrepancy between the actual energy use and theoretical calculations, remains a persistent issue in building design. This study examines the energy performance of three multifamily buildings with a collective heating system powered by gas boilers and solar collectors: two that underwent deep renovation and one newly built. An extensive on-site monitoring system provides detailed data on both the heating demand and the final energy use. To ensure comparability, the total energy use of each unit is normalised using the energy signature method. The findings show the large spread of actual energy demands due to a wide variation in user profiles. The majority of dwellings have an actual energy use that is significantly higher than calculated, which is largely attributable to space heating. The gap is further exacerbated by substantial heat losses within the building’s heating system and by limited gains from the solar collectors, indicating discrepancies between design models and operational realities. To bridge this gap, there is a need for rigorous commissioning processes, at least during the initial operation phase start-up and ideally continuously. This can ensure more effective utilisation of renewable energy sources and reduce energy inefficiencies.

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Honda, M., J. Meyer-ter-Vehn e A. Pukhov. "Collective Stopping and Ion Heating in Relativistic-Electron-Beam Transport for Fast Ignition". Physical Review Letters 85, n. 10 (4 settembre 2000): 2128–31. http://dx.doi.org/10.1103/physrevlett.85.2128.

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Salewski, M., F. Meo, H. Bindslev, V. Furtula, S. B. Korsholm, B. Lauritzen, F. Leipold, P. K. Michelsen, S. K. Nielsen e E. Nonbøl. "Investigation of first mirror heating for the collective Thomson scattering diagnostic in ITER". Review of Scientific Instruments 79, n. 10 (ottobre 2008): 10E729. http://dx.doi.org/10.1063/1.2956961.

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Gafsi, Afef, e Gilles Lefebvre. "Stolen heating or cooling energy evaluation in collective buildings using model inversion techniques". Energy and Buildings 35, n. 3 (marzo 2003): 293–303. http://dx.doi.org/10.1016/s0378-7788(02)00093-2.

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Jungclas, H., L. Schmidt, V. V. Komarov, A. M. Popova e I. O. Stureiko. "Local Heating and Dissociation of Organic Molecules by IR Fields". Zeitschrift für Naturforschung A 59, n. 12 (1 dicembre 2004): 964–70. http://dx.doi.org/10.1515/zna-2004-1214.

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A nonstatistical model for internal transition of collective vibrational energy to specific bonds in organic molecules is presented. The model is developed for molecules which contain a chain of identical biatomic dipoles, e.g. C-H groups. Resonant IR fields can induce collective vibrational excitations (excimols) in the dipole chain. The accumulated vibrational energy can be transmitted to particular bonds, which are not part of the chain but close enough for dipole-dipole interactions. Specific properties of such bonds enable a pile up of harvested excimol energy there, thus making dissociation of these bonds a likely exit channel. An analytical expression for the calculation of dissociation probabilities was derived and analysed. It is shown that the dissociation probability strongly depends on the position and orientation of the bond relative to the position and orientation of the dipoles in the chain. The consequences of the presented model were experimentally checked by comparing the fragmentation of the isomers Leucine and Isoleucine. - PACS: 30.00 - 34.10 - 36.40

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Vivian, Jacopo, Mattia Chinello, Angelo Zarrella e Michele De Carli. "Investigation on Individual and Collective PV Self-Consumption for a Fifth Generation District Heating Network". Energies 15, n. 3 (29 gennaio 2022): 1022. http://dx.doi.org/10.3390/en15031022.

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Renewable Energy Communities have been recently introduced in European legislation to promote distributed generation from renewable energy sources. In fact, they allow to produce and consume energy from shared local power plants. Low temperature district heating and cooling networks with distributed heat pumps have demonstrated their capability to exploit renewable and waste heat sources in the urban environment. Therefore, they are considered a promising infrastructure to help decarbonize the building sector. As their main operating cost is the electricity purchased by the utility for heat pumps and circulation pumps, this work investigates whether a Renewable Energy Community could help mitigate such cost by sharing electricity produced by local photovoltaic (PV) systems. The research relies on computer simulations performed with both physical and statistical models for the evaluation of electrical load profiles at the district level. Results show that due to the different seasonality between heating demand and PV production, the increase in self-consumption due to the distributed heat pumps is lower than 10%. The use of batteries does not seem convenient for the same reason. The environmental benefit of the proposed system is evident, with CO2 emissions reduced by 72–80% compared to the current situation depending on PV power installed. It also emerged that PV sharing significantly improves the self-consumption at the district level, in particular when the installed PV power is limited (+45%). In conclusion, results suggest that current incentives on PV-sharing make Renewable Energy Communities a viable option to improve the techno-economic performance of fifth-generation district heating and cooling networks.

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Rypdal, K. "Acceleration and heating in quasi-linear diffusion". Journal of Plasma Physics 35, n. 3 (giugno 1986): 413–29. http://dx.doi.org/10.1017/s0022377800011430.

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Quasi-linear diffusion of charged particles due to a stationary and homogeneous spectrum of electrostatic field fluctuations is investigated via a Fokker-Planck approach. The energy of a given distribution of test particles is found to be conserved whenever the wave spectrum is isotropic and none of the spectral components of the field has a phase speed that equals the speed of any test particle. Quite generally, the energy is monotonically increasing for isotropic spectra. An interesting quantum mechanical interpretation of these results is given, and the special case of beam evolution in an isotropic spectrum of non-dispersive waves is studied in some detail. Conditions for isotropization of directed electron and ion beams from Coulomb collisions and collective oscillations are discussed in the context of the quasi-linear description. Some promising results from a beam-plasma experiment are quoted.

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Baetens, Robin, e Ivan Verhaert. "A new test procedure to evaluate the performance of substations for collective heating systems". E3S Web of Conferences 22 (2017): 00006. http://dx.doi.org/10.1051/e3sconf/20172200006.

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Jacobs, Stef, Margot De Pauw, Senne Van Minnebruggen, Sara Ghane, Thomas Huybrechts, Peter Hellinckx e Ivan Verhaert. "Grouped Charging of Decentralised Storage to Efficiently Control Collective Heating Systems: Limitations and Opportunities". Energies 16, n. 8 (13 aprile 2023): 3435. http://dx.doi.org/10.3390/en16083435.

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Collective heating systems have multiple end-users with time-varying, often different temperature demands. There are several concepts catering to this, e.g., multi-pipe networks and 2-pipe networks with or without decentralised booster systems. In this study, we focus on 2-pipe networks with a changing supply temperature by smart use of decentralised storage. By grouping high-temperature demands, the average supply temperature can be lowered during large parts of the day, which is beneficial for system efficiency. The actual energy-saving potential, however, can be case-specific and is expected to depend on design choices and implemented control strategies. In this paper, these dependencies are assessed and identified by implementing two optimised rule-based control strategies, providing in such a way a bench-mark for other control strategies. The results show that grouping yields energy savings of up to 36% at similar peak demand as with conventional control strategies. The energy-saving potential is greatest for large storage volumes and small networks, but large networks with large storage and proper control choices can also achieve around 30% energy savings. Moreover, high-temperature time can easily be reduced to less than 40% of the day, which could make space cooling without decentralised booster heat pumps possible, but this requires further research.

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Nagaoka, Ryutaro, e Karl L. F. Bane. "Collective effects in a diffraction-limited storage ring". Journal of Synchrotron Radiation 21, n. 5 (27 agosto 2014): 937–60. http://dx.doi.org/10.1107/s1600577514015215.

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This paper gives an overview of collective effects that are likely to appear and possibly limit the performance in a diffraction-limited storage ring (DLSR) that stores a high-intensity ultra-low-emittance beam. Beam instabilities and other intensity-dependent effects that may significantly impact the machine performance are covered. The latter include beam-induced machine heating, Touschek scattering, intra-beam scattering, as well as incoherent tune shifts. The general trend that the efforts to achieve ultra-low emittance result in increasing the machine coupling impedance and the beam sensitivity to instability is reviewed. The nature of coupling impedance in a DLSR is described, followed by a series of potentially dangerous beam instabilities driven by the former, such as resistive-wall, TMCI (transverse mode coupling instability), head–tail and microwave instabilities. In addition, beam-ion and CSR (coherent synchrotron radiation) instabilities are also treated. Means to fight against collective effects such as lengthening of the bunch with passive harmonic cavities and bunch-by-bunch transverse feedback are introduced. Numerical codes developed and used to evaluate the machine coupling impedance, as well as to simulate beam instability using the former as inputs are described.

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Maksimov, I. L. "Thermal Instability of Sliding and Oscillations Due to Frictional Heating Effect". Journal of Tribology 110, n. 1 (1 gennaio 1988): 69–72. http://dx.doi.org/10.1115/1.3261577.

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The stability of sliding has been studied, taking into account frictional heating effect and friction coefficient dependence upon the interface temperature and sliding velocity. The collective—thermal and mechanical—sliding instability has been found to exist; instability emergence conditions and dynamics (both in linear and nonlinear stages) have been determined. It is shown that both the threshold and the dynamics of thermofrictional instability differ qualitatively from the analogous characteristics of “stick-slip” phenomenon. Namely, the oscillational instability behavior due to the energy exchange between thermal and mechanical modes has been found to occur under certain initial conditions; the velocities range has been determined for which collective sliding instability may occur whereas the stick-slips would be not possible. The nonlinear analysis of instability evolution has been carried out for pairs with the negative thermal-frictional sliding characteristics, the final stage of sliding dynamics has been described. It is found that stable thermofrictional oscillations can occur on the nonlinear stage of sliding instability development; the oscillations frequency and amplitude have been determined. The possibility has been discussed of the experimental observation of new dynamical sliding phenomena at low temperatures.

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Kasparek, W., V. Erckmann, H. P. Laqua, T. Stange, M. Weißgerber, C. Lechte, B. Plaum et al. "Optics for electron cyclotron resonance heating and collective Thomson scattering at the stellarator W7-X". EPJ Web of Conferences 149 (2017): 01013. http://dx.doi.org/10.1051/epjconf/201714901013.

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Dennis, C. L., A. J. Jackson, J. A. Borchers, R. Ivkov, A. R. Foreman, J. W. Lau, E. Goernitz e C. Gruettner. "The influence of collective behavior on the magnetic and heating properties of iron oxide nanoparticles". Journal of Applied Physics 103, n. 7 (aprile 2008): 07A319. http://dx.doi.org/10.1063/1.2837647.

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Kubo, S., M. Nishiura, K. Tanaka, T. Shimozuma, Y. Yoshimura, H. Igami, H. Takahash et al. "Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD (invited)". Review of Scientific Instruments 81, n. 10 (ottobre 2010): 10D535. http://dx.doi.org/10.1063/1.3481165.

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Sharma, Ram Prakash, S. R. Mishra, Seema Tinker e B. K. Kulshrestha. "Exploration of Radiative and Dissipative Heat on Williamson Nanofluid Flow in Conjunction with Convective Boundary Condition". Journal of Nanofluids 12, n. 1 (1 febbraio 2023): 223–30. http://dx.doi.org/10.1166/jon.2023.1950.

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Nanofluid has a wide range of uses in various fluid systems, because of its excellent growth in thermal conductivity. The current paper explores the transfer of heat and mass process in MHD nanofluid flow across a stretching sheet, considering the collective impacts of nonlinear thermal radiation, Joule heating, and binary chemical reactions with convective boundary conditions for Williamson nanofluid. The necessary transformations are carried out to alter the controlling PDE’s into a collection of linked ODE’s. The shooting approach, in conjunction with the fourth-order Runge–Kutta method, is employed to get solutions to highly nonlinear ODE’s. The impact of varied main factors on velocity, temperature, concentration, for Weissenberg number, Biot number along with other parameters are depicted graphically, whilst the change in the rate of heat and mass transfer is investigated via numerical data in tabular form. The acquired numerical data show that expanding the Eckert number diminishes the rate of mass transfer whereas expanding the thermal radiation parameter, expandsthe rate of heatand rate of mass transfer.

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Tracy, E. R., A. J. Brizard e A. N. Kaufman. "Generalized Case—van Kampen modes in a multidimensional non-uniform plasma with application to gyroresonance heating". Journal of Plasma Physics 55, n. 3 (giugno 1996): 449–86. http://dx.doi.org/10.1017/s0022377800018985.

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The generalization of the Case—van Kampen analysis to a multidimensional non-uniform plasma is presented. Application of this analysis is made to minority-ion gyrolesonant heating in an axisymmetric tokamak. In previous work the Case—van Kampen analysis, in conjunction with the Bateman—Kruskal algorithm, was used in a one-dimensional slab model to compute the collective wave spin-off (to the minority-ion Bernstein wave) and the gyroballistic continuum for minority gyroresonant absorption. The generalization to many gyroresonant dimensions and non-trivial geometries requires several important new developments: In tokamak geometry particles can be trapped, an effect that is absent in the slab model. Also, the ray propagation dynamics for both the flee gyroballistic waves and the collective minority-ion Bernstein wave is far more complicated than in the slab model. In particular, a resonance zone is identified wherein the gyroballistic waves interact strongly and cannot be treated as free. We use the Weyl calculus to construct a local form of the self-consistent gyroballistic equation within the resonance zone. This reduced equation is simplified via a metaplectic transformation (a generalization of the Fourier tiansformation). After this simplification, the equation is shown to be of Case—van Kampen type with weak non-uniformities; hence there are no true Case—van Kampen eigenfunctions. Using the Bateman—Kruskal approach, a local Case—van Kampen basis can be constructed and the initial-value problem solved. The self-consistent interactions of the gyroballistic continuum lead to a collective wave, the minority-ion Bernstein wave. The Bernstein wave is extracted by the spectral deformation approach of Crawford and Hislop. The relevance of this work to the theory of collective phenomena in nonlinear oscillator ensembles is briefly discussed.

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Simeni Simeni, M., A. S. Davies e A. Diallo. "Toward streaked collective Thomson scattering measurements on an extreme ultraviolet plasma light source". Review of Scientific Instruments 94, n. 4 (1 aprile 2023): 043501. http://dx.doi.org/10.1063/5.0131598.

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We show through forward modeling calculations that streaked collective Thomson scattering measurements are feasible on laser-produced tin plasmas generated under conditions relevant for extreme ultraviolet lithography. Using a 532 nm probe laser beam, the feasibility of simultaneous measurements of electron plasma wave (EPW) and ion acoustic wave (IAW) spectra is investigated. Absolute photon counts for laser scattering off both waves are calculated. Probe laser electron heating and bremsstrahlung background radiation effects are accounted for. While a large spatiotemporal region can be successfully probed based on the IAW feature, only one measurement location can be accessed through the EPW as a result of the low signal to noise ratio. A portable/traveling tabletop system is proposed.

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Sentoku, Mitsuru, Hiromichi Hashimoto, Kento Iida, Masaharu Endo e Kenji Yasuda. "Photothermal Agarose Microfabrication Technology for Collective Cell Migration Analysis". Micromachines 12, n. 9 (26 agosto 2021): 1015. http://dx.doi.org/10.3390/mi12091015.

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Agarose photothermal microfabrication technology is one of the micropatterning techniques that has the advantage of simple and flexible real-time fabrication even during the cultivation of cells. To examine the ability and limitation of the agarose microstructures, we investigated the collective epithelial cell migration behavior in two-dimensional agarose confined structures. Agarose microchannels from 10 to 211 micrometer width were fabricated with a spot heating of a focused 1480 nm wavelength infrared laser to the thin agarose layer coated on the cultivation dish after the cells occupied the reservoir. The collective cell migration velocity maintained constant regardless of their extension distance, whereas the width dependency of those velocities was maximized around 30 micrometer width and decreased both in the narrower and wider microchannels. The single-cell tracking revealed that the decrease of velocity in the narrower width was caused by the apparent increase of aspect ratio of cell shape (up to 8.9). In contrast, the decrease in the wider channels was mainly caused by the increase of the random walk-like behavior of component cells. The results confirmed the advantages of this method: (1) flexible fabrication without any pre-designing, (2) modification even during cultivation, and (3) the cells were confined in the agarose geometry.

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Verhaert, Ivan. "Design methodology for combined production and distribution for domestic hot water and space heating". E3S Web of Conferences 111 (2019): 01089. http://dx.doi.org/10.1051/e3sconf/201911101089.

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As local heat demand is reducing due to an increased insulation rate, investing in sustainable heat production becomes less interesting. Nevertheless a substantial demand of heat remains in which the thermal energy needed for the generation of domestic hot water grows relatively in importance. In the last two years standards to size production and distribution systems were revised and methods based on tap patterns were elaborated. Nevertheless, some aspects were not covered yet, e.g. how to deal with decentralized storage and how to use these results and new insights in combined heating systems, taking into account that modifications in standards for both space heating and domestic hot water installations are reducing the oversizing. In this paper, first some critical points of attention due to this evolution are illustrated with a case example. Next it is shown how different rules of thumb often developed by different manufacturers deal with these aspects, but lacking however compatibility with existing standards and/or new insights. Finally, a methodology is proposed and illustrated how to size distribution and production systems for combined heating systems taking into account central and decentralized storage and different kind of end users. The method can be used to size heating systems in collective housing or in district heating networks.

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Poedts, Stefaan, e Wolfgang Kerner. "Time scales and efficiency of resonant absorption in periodically driven resistive plasmas". Journal of Plasma Physics 47, n. 1 (febbraio 1992): 139–62. http://dx.doi.org/10.1017/s0022377800024120.

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The time scales and efficiency of plasma heating by resonant absorption of Alfvén waves are studied in the framework of linearized compressible and resistive magnetohydrodynamics. The configuration considered consists of a straight cylindrical axisymmetric plasma column surrounded by a vacuum region and a perfectly conducting shell. The plasma is excited periodically by an external source, located in the vacuum region. The temporal evolution of this driven system is simulated numerically. It is shown that the so-called ‘ideal quasi-modes’ (or ‘collective modes’) play a fundamental role in resonant absorption, and affect both the temporal evolution of the driven system and the efficiency of this heating mechanism considerably. The variation of the energetics in periodically driven resistive systems is analysed in detail for three different choices of the driving frequency, viz an arbitrary continuum frequency, the frequency of an ideal ‘quasi-mode’, and a discrete Alfvén wave frequency. The consequences for Alfvén wave heating of both laboratory plasmas and solar coronal loops are discussed.

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Krishnamurti, T. N., Arindam Chakraborty e A. K. Mishra. "Improving Multimodel Forecasts of the Vertical Distribution of Heating Using the TRMM Profiles". Journal of Climate 23, n. 5 (1 marzo 2010): 1079–94. http://dx.doi.org/10.1175/2009jcli2878.1.

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Abstract Recently the National Aeronautics and Space Administration (NASA) Tropical Rainfall Measuring Mission (TRMM) project office made available a new product called the convective–stratiform heating (CSH). These are the datasets for vertical profiles of diabatic heating rates (the apparent heat source). These observed estimates of heating are obtained from the TRMM satellite’s microwave radiances and the precipitation radar. The importance of such datasets for defining the vertical distribution of heating was largely the initiative of Dr. W.-K. Tao from NASA’s Goddard Laboratory. The need to examine how well some of the current cumulus parameterization schemes perform toward describing the amplitude and the three-dimensional distributions of heating is addressed in this paper. Three versions of the Florida State University (FSU) global atmospheric model are run that utilize different versions of cumulus parameterization schemes; namely, modified Kuo parameterization, simple Arakawa–Schubert parameterization, and Zhang–McFarlane parameterization. The Kuo-type scheme used here relies on moisture convergence and tends to overestimate the rainfall generally compared to the TRMM estimates. The other schemes used here show only a slight overestimate of rain rates compared to TRMM; those invoke mass fluxes that are less stringent in this regard in defining cloud volumes. The mass flux schemes do carry out a total moisture budget for a vertical column model and include all components of the moisture budget and are not limited to the horizontal convergence of moisture. The authors carry out a numerical experimentation that includes over a hundred experiments from each of these models; these experiments differ only in their use of the cumulus parameterization. The rest of the model physics, resolution, and initial states are kept the same for each set of 117 forecasts. The strategy for this experimentation follows the authors’ previous studies with the FSU multimodel superensemble. This includes a 100-day training and a 17-day forecast phase, both of which include a large number of forecast experiments. The training phase provides a useful statistical database for tagging the systematic errors of the respective models. The forecast phase is designed to minimize the collective bias errors of these member models. In these forecasts the authors also include the ensemble mean and the multimodel superensemble. In this paper the authors examine model errors in their representations of the heating (amplitude, vertical level of maximum, and the geographical distributions). The main message of this study is that some cumulus parameterization schemes overestimate the amplitude of heating, whereas others carry lower values. The models also exhibit large errors in the placement of the vertical level of maximum heating. Some significant errors were also found in the geographical distributions of heating. The ensemble mean largely mimics the model features and also carries some large errors. The superensemble is more selective in reducing the three-dimensional collective bias errors of the models and provides the best short range forecasts, through hour 60, for the heating. This study shows that it is possible to diagnose some of the modeling errors in the heating for individual member models and that information can be important for correcting such features.

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Chiu, Chi-Shun, Hung-Ying Chen, Chun-Fang Hsiao, Meng-Hsien Lin e Shangjr Gwo. "Ultrasensitive Surface Acoustic Wave Detection of Collective Plasmonic Heating by Close-Packed Colloidal Gold Nanoparticles Arrays". Journal of Physical Chemistry C 117, n. 6 (7 agosto 2012): 2442–48. http://dx.doi.org/10.1021/jp3030864.

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Van Riet, Freek, Eddy Janssen, Gunther Steenackers e Ivan Verhaert. "Hydronic design of cogeneration in collective residential heating systems: state-of-the-art, comparison and improvements". Applied Thermal Engineering 148 (febbraio 2019): 1246–57. http://dx.doi.org/10.1016/j.applthermaleng.2018.12.004.

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Kizilkale, Arman C., e Roland P. Malhame. "Collective Target Tracking Mean Field Control for Markovian Jump-Driven Models of Electric Water Heating Loads". IFAC Proceedings Volumes 47, n. 3 (2014): 1867–72. http://dx.doi.org/10.3182/20140824-6-za-1003.00630.

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DeRocco, William, Marios Galanis e Robert Lasenby. "Dark matter scattering in astrophysical media: collective effects". Journal of Cosmology and Astroparticle Physics 2022, n. 05 (1 maggio 2022): 015. http://dx.doi.org/10.1088/1475-7516/2022/05/015.

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Abstract It is well-known that stars have the potential to be excellent dark matter detectors. Infalling dark matter that scatters within stars could lead to a range of observational signatures, including stellar heating, black hole formation, and modified heat transport. To make robust predictions for such phenomena, it is necessary to calculate the scattering rate for dark matter inside the star. As we show in this paper, for small enough momentum transfers, this requires taking into account collective effects within the dense stellar medium. These effects have been neglected in many previous treatments; we demonstrate how to incorporate them systematically, and show that they can parametrically enhance or suppress dark matter scattering rates depending on how dark matter couples to the Standard Model. We show that, as a result, collective effects can significantly modify the potential discovery or exclusion reach for observations of compact objects such as white dwarfs and neutron stars. While the effects are more pronounced for dark matter coupling through a light mediator, we show that even for dark matter coupling via a heavy mediator, scattering rates can differ by orders of magnitude from their naive values for dark matter masses ≲ 100 MeV. We also illustrate how collective effects can be important for dark matter scattering in more dilute media, such as the Solar core. Our results demonstrate the need to systematically incorporate collective effects in a wide range of astroparticle contexts; to facilitate this, we provide expressions for in-medium self-energies for a variety of different media, which are applicable to many other processes of interest (such as particle production).

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Aksenov, Andrey. "Heat transfer from the collective finning of pipes in heat exchangers under asymmetric boundary conditions". E3S Web of Conferences 91 (2019): 02009. http://dx.doi.org/10.1051/e3sconf/20199102009.

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The solution of the problem of the heat flux from the surface of collective finning at various temperatures of its ends is given. The obtained analytical formulas allow giving a quantitative estimate of the influence of the asymmetry of the boundary conditions on the heat transfer through the finned heat exchange surface. Calculated dependencies can be used in the design of high-efficiency heat exchangers for air conditioning, ventilation, and heating systems. The presented results can be especially useful under real operating conditions of heat exchange surfaces. This, in turn, ensures the safe and reliable operation of the building’s engineering systems as a whole.

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Hellmer, Stefan. "Price Responsiveness in District Heating: Single Houses and Residential Buildings—a Cross-Sectional Analysis". ISRN Economics 2013 (4 aprile 2013): 1–4. http://dx.doi.org/10.1155/2013/324127.

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Price responsiveness is argued to be one important factor determining the possibility for a natural monopoly such as a district heating company to exercise its monopoly power. Increased price responsiveness, measured, for example, by the own price elasticity, reduces monopoly power, as consumers increasingly reduce demand as a response to a price increase. However, consumers in single houses having individual metering have presumably higher price responsiveness compared to consumers in residential buildings using collective metering. One major question raised in this paper is thus whether single houses show larger price responsiveness compared to residential buildings. Using cross-sectional data for 187 networks in Sweden for the year 2007 indicates that even if single houses have higher price responsiveness, district heating reveals in general a very inelastic behavior.

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Eckersley, Robyn. "(Dis)order and (in)justice in a heating world". International Affairs 99, n. 1 (9 gennaio 2023): 101–19. http://dx.doi.org/10.1093/ia/iiac259.

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Abstract Conventional accounts of the relationship between international order and justice treat order as necessarily prior to justice because it is a precondition for the management of conflict and for collective debates about justice. This contribution takes the climate change challenge as an opportunity to challenge and enlarge this account from the perspective of critical political ecology. This approach highlights the more fundamental socio-ecological conditions that are necessary for the stability and possibility of political order itself. It also directs more systematic attention to how orders themselves disorder the climate in ways that also constitute climate injustices. Structurally generated injustices of this kind cannot be addressed solely at the level of a single regime (via the Paris Agreement). They also require a transformation of the constitutive norms and practices of the international liberal economic order in which the climate regime is embedded so that the order serves the objectives and principles of the regime. However, this is unlikely, and the contribution reflects on the implications for the legitimacy and functional viability of states and the international order in a heating world.

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Jeon, Yong-Woo. "Development of a System Suitable for an Apartment Complex for the Collective Recovery of Solid Resources from Food Waste: A Study on South Korea". Sustainability 16, n. 13 (2 luglio 2024): 5665. http://dx.doi.org/10.3390/su16135665.

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The installation of food waste disposers has been prohibited in South Korea, due to conflicts with governmental policies that are focused on resource recovery from food waste and concerns about potential damage to the city’s sewer system. However, there is a growing demand for such systems in the country. This study proposes a system for the collective recovery of solid resources from food waste tailored for apartment complexes in South Korea, using an innovative solid–liquid separation technology. In the pilot experiment, 49.60% of the solids fed into the system were recovered as solid matter, confirming its practical applicability. Ultimately, a solid resource collective recovery system suitable for the high-rise apartment residence style of South Korea was developed and applied to an actual apartment complex. The final-stage solids were discharged from the system and processed through bio-drying, subsequently exhibiting a combustible material content of 67.06%, higher heating value (HHV) of 4843 kcal/kg, and lower heating value (LHV) of 3759 kcal/kg; moreover, they have the potential to be repurposed as biomass–solid refuse fuel (bio-SFR), compost, feed, and substrate for biogas production. The proposed food waste disposal system not only aligns with governmental policies, but also facilitates the recovery of high-quality resources from food waste, while providing a sustainable waste management solution.

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Dattilo, Anna, Francesco Melino, Mattia Ricci e Paolo Sdringola. "Optimizing Thermal Energy Sharing in Smart District Heating Networks". Energies 17, n. 12 (14 giugno 2024): 2936. http://dx.doi.org/10.3390/en17122936.

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The constant attention to sustainability aimed at reconciling economic and social development with environmental protection is the driving force of the continuous growth of renewable energy in the energy sector. Among the numerous actions taken by the European Commission (EC) in this direction, an important initiative towards the complete decarbonization is represented by the Renewable Energy Communities (RECs). According to the EC, “energy communities enable collective and citizen-driven energy actions to support the clean energy transition. They can contribute to increasing public acceptance of renewable energy projects and make it easier to attract private investments in the clean energy transition”. At the European level, numerous energy communities are emerging, although they are all based on photovoltaic production and, consequently, focus only on electricity flows. The aim of this paper is to define a thermal energy community in which thermal energy sharing can be achieved by exploiting the concept of the smart district heating network. Starting from a small existing district heating network, its conversion into a smart one will be analyzed and optimized with the aim of studying the sharing of thermal energy between the various prosumer and non-prosumer users connected to the district heating network.

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Jo, Sunghan, e Hyun Jae Kim. "Study on the New Renewable Energy Output of Geothermal Cooling and Heating System for Collective Residential Facilities". Journal of the Korean Society of Mineral and Energy Resources Engineers 57, n. 6 (1 dicembre 2020): 593–99. http://dx.doi.org/10.32390/ksmer.2020.57.6.593.

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Richardson, Hugh H., Michael T. Carlson, Peter J. Tandler, Pedro Hernandez e Alexander O. Govorov. "Experimental and Theoretical Studies of Light-to-Heat Conversion and Collective Heating Effects in Metal Nanoparticle Solutions". Nano Letters 9, n. 3 (11 marzo 2009): 1139–46. http://dx.doi.org/10.1021/nl8036905.

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Tsao, Shao Hsuan, Dehui Wan, Yu-Sheng Lai, Ho-Ming Chang, Chen-Chieh Yu, Keng-Te Lin e Hsuen-Li Chen. "White-Light-Induced Collective Heating of Gold Nanocomposite/Bombyx mori Silk Thin Films with Ultrahigh Broadband Absorbance". ACS Nano 9, n. 12 (12 novembre 2015): 12045–59. http://dx.doi.org/10.1021/acsnano.5b04913.

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Cholewa e Siuta-Olcha. "On the Use of Residential Thermal Stations in Different Types of Buildings". Proceedings 16, n. 1 (5 luglio 2019): 36. http://dx.doi.org/10.3390/proceedings2019016036.

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The main purpose of this paper is to analyze the energy consumption and the efficiency of heating systems in two multi-family buildings and one collective residence equipped with residential thermal stations (RTSs) that are used for supplying individual dwellings with heat as well as hot and cold water. An additional aspect of the analysis is a presentation of the structure of total energy consumption for particular purposes in the analyzed buildings.

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Schneider, S., e P. Hollmuller. "EvalCADair: tool for assessing air quality improvement after the deployment of a district heating network". Journal of Physics: Conference Series 2600, n. 10 (1 novembre 2023): 102001. http://dx.doi.org/10.1088/1742-6596/2600/10/102001.

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Abstract Switching from individual fossil fuel boilers to a district heating network not only allows the reduction of CO2 emissions but may also lead to significant reduction of other air pollutants such as SO2, NOx and PMx, which have well known negative effects on the human health. EvalCADair makes it possible to estimate the annual evolution of the emissions of atmospheric pollutants during the construction phase of a district heating network. This generic tool is applied to the case of the district heating network CADéco, whose heat production consists of centralized heat pumps and gas boilers. Located in Geneva, the case study includes 154 buildings with a total heated surface of 547’000 m2 and an annual heat demand of about 55 GWh. Approximately half of the total surface aera is dedicated to collective residential housing and the rest to various activities. By the end of 2022, 40% of these buildings were connected to the district heating network. Using the tool to estimate the emissions from 2011 to 2022 shows only a small reduction in CO2 emissions, mainly due to the replacement of individual oil boilers with centralized gas boilers. The gain will be more significant when the heat pumps will be activated. The future impact of the activation of the heat pumps is estimated using EvalCADair as a prospective tool.

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Zhou, Zhiyong, Liming Wang, Chunxia Li e Alan Ebert. "Performance Analysis of a Collective Solar Domestic Water - Heating System in the Temperate Zone of Yunnan Province, China". Journal of Engineering Science and Technology Review 2016, n. 3 (giugno 2016): 60–65. http://dx.doi.org/10.25103/jestr.093.09.

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Salewski, M., O. Asunta, L.-G. Eriksson, H. Bindslev, V. Hynönen, S. B. Korsholm, T. Kurki-Suonio et al. "Comparison of collective Thomson scattering signals due to fast ions in ITER scenarios with fusion and auxiliary heating". Plasma Physics and Controlled Fusion 51, n. 3 (31 dicembre 2008): 035006. http://dx.doi.org/10.1088/0741-3335/51/3/035006.

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Jungclas, H., L. Schmidt, V. V. Komarov, A. M. Popova e I. O. Stureikoa. "Resonant IR Photon Induced Dissociation in Organic Molecules with Chain-like Substructures". Zeitschrift für Naturforschung A 57, n. 5 (1 maggio 2002): 270–76. http://dx.doi.org/10.1515/zna-2002-0511.

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A nonstatistical model for the resonant IR photon induced dissociation of organic molecules by IR photons is suggested. The model is based on the excimol theory for molecules which contain chains of identical diatomic dipole groups. IR photon radiation can induce resonantly collective vibrational excitations (excimols) in these molecular substructures. The accumulation of several excimols in the molecular chain causes a local heating of the molecule and its fragmentation on a time scale of several hundreds of femtoseconds. An analytical expression for the fragmentation probability is derived and analysed.

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Büscher, Christian, Dirk Scheer e Lisa Nabitz. "Future converging infrastructures". TATuP - Zeitschrift für Technikfolgenabschätzung in Theorie und Praxis 29, n. 2 (17 luglio 2020): 17–23. http://dx.doi.org/10.14512/tatup.29.2.17.

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The process of converging infrastructures – the integration and coupling of the energy, transport, heating and cooling sectors – challenges technological paradigms and economic structures as well as patterns of individual and collective action. Renewable energy sources (RES), physical and digital networks, and new market opportunities promise more efficient use of energy and reduced emissions. However, every technological solution creates new problems. Therefore, we propose to analyze possible developments by exposing socio-technical problems. This contribution analyses recent studies drawing on sector coupling and assesses the consequences of converging infrastructures.

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Zatti, Matteo, Federico Guermandi e Filippo Bovera. "Techno-economic impact of collective self-consumption on different energy-related investments for a condominium". E3S Web of Conferences 238 (2021): 05006. http://dx.doi.org/10.1051/e3sconf/202123805006.

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Energy Communities (ECs) are gaining a key role in supporting the transition towards a low carbon economy in EU, since they combine the promotion of efficient energy practices with an expected positive social impact. Legislators are resorting to the concept of collective self-consumption as a tool to favor the electrification of energy needs and the diffusion of renewable energy sources. This work presents the first results in this field of the ENERGYNIUS project, co-funded by Regione Emilia-Romagna, focusing on the economic feasibility of investment decisions that would increase energy efficiency and renewables’ penetration in the household sector. To this purpose, a mathematical model has been developed, featuring an hourly time step definition of the internal and external energy exchanges and an accurate modelling of the electricity billing. It has been applied to an Italian condominium case study where the energy requirements of the inhabitants – in terms of electricity, heating, cooling and private transportation – have been considered. Thanks to the model, it is possible to compare increasing levels of electrification (e.g., photovoltaic panels, heat pumps, electric vehicles and batteries) and assess the benefits of collective selfconsumption on the condominium cash flows and environment (fossil CO2 emissions).

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Rohani, Shadi, Marta Quintanilla, Salvatore Tuccio, Francesco De Angelis, Eugenio Cantelar, Alexander O. Govorov, Luca Razzari e Fiorenzo Vetrone. "Enhanced Luminescence, Collective Heating, and Nanothermometry in an Ensemble System Composed of Lanthanide-Doped Upconverting Nanoparticles and Gold Nanorods". Advanced Optical Materials 3, n. 11 (19 agosto 2015): 1606–13. http://dx.doi.org/10.1002/adom.201500380.

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