152 research outputs found
Activation of demand flexibility for heating systems in buildings:Real-life demonstration of optimal control for power-to-heat and thermal energy storage
Activation of demand flexibility for heating systems in buildings:Real-life demonstration of optimal control for power-to-heat and thermal energy storage
An Optimization Strategy for Scheduling Various Thermal Energy Storage Technologies in Office Buildings Connected to Smart Grid
AbstractAn optimization strategy for scheduling various thermal energy storage capacities in an office building is investigated. An activated building wall (building thermal mass), a phase change material (PCM) tank, a hot water (HW) tank and a thermochemical material (TCM) storage are simulated and their charging and discharging behavior are optimized. Therefore, a case study is performed using a very simplified room model (office) and typical weather data for the Netherlands. To model the storage's scheduling behavior for control and optimization, a resistance capacitance (RC) network is applied. The RC network represents the critical energy storage parameters for optimization and control. The minimization of electricity costs is defined as optimization objective towards the Smart Grid. Cost saving potentials up to 12.5% are calculated using an electrical heat pump and a solar collector for heating the room and charging the thermal energy storage capacities
Are building users prepared for energy flexible buildingsâA large-scale survey in the Netherlands
Building energy flexibility might play a crucial role in demand side management for integrating intermittent renewables into smart grids. The potential of building energy flexibility depends not only on the physical characteristics of a building but also on occupant behaviour in the building. Building users will have to adopt smart technologies and to change their daily energy use behaviours or routines, if energy flexibility is to be achieved. The willingness of users to make changes will determine how much demand flexibility can be achieved in buildings and whether energy flexible buildings can be realized. This will have a considerable impact on the transition to smart grids. This study is thus to assess the perception of smart grids and energy flexible buildings by building users, and their readiness for them on a large scale. We attempted to identify the key characteristics of the ideal user of flexible buildings. A questionnaire was designed and administered as an online survey in the Netherlands. The questionnaire consisted of questions about the sociodemographic characteristics of the current users, house type, household composition, current energy use behaviour, willingness to use smart technologies, and willingness to change energy use behaviour. The survey was completed by 835 respondents, of which 785 (94%) were considered to have provided a genuine response. Our analysis showed that the concept of smart grids is an unfamiliar one, as more than 60% of the respondents had never heard of smart grids. However, unfamiliarity with smart grids increased with age, and half of the respondents aged 20â29 years old were aware of the concept. Monetary incentives were identified as the biggest motivating factor for adoption of smart grid technologies. It was also found that people would be most in favour of acquiring smart dishwashers (65% of the respondents) and refrigerator/freezers (60%). Statistical analysis shows that people who are willing to use smart technologies are also willing to change their behaviour, and can thus be categorised as potentially flexible building users. Given certain assumptions, 11% of the respondents were found to be potentially flexible building users. To encourage people to be prepared for energy flexible buildings, awareness of smart grids will have to be increased, and the adoption of smart technologies may have to be promoted by providing incentives such as financial rewards
Dosimetry and characterization of a 25âMeV proton beam line for preclinical radiobiology research
International audienc
Exploiting neutron-rich radioactive ion beams to constrain the symmetry energy
The Modular Neutron Array (MoNA) and 4 Tm Sweeper magnet were used to measure
the free neutrons and heavy charged particles from the radioactive ion beam
induced 32Mg + 9Be reaction. The fragmentation reaction was simulated with the
Constrained Molecular Dynamics model(CoMD), which demonstrated that the
of the heavy fragments and free neutron multiplicities were observables
sensitive to the density dependence of the symmetry energy at sub-saturation
densities. Through comparison of these simulations with the experimental data
constraints on the density dependence of the symmetry energy were extracted.
The advantage of radioactive ion beams as a probe of the symmetry energy is
demonstrated through examination of CoMD calculations for stable and
radioactive beam induced reactions
Three-body correlations in the ground-state decay of 26O
Background: Theoretical calculations have shown that the energy and angular
correlations in the three-body decay of the two-neutron unbound O26 can provide
information on the ground-state wave function, which has been predicted to have
a dineutron configuration and 2n halo structure.
Purpose: To use the experimentally measured three-body correlations to gain
insight into the properties of O26, including the decay mechanism and
ground-state resonance energy.
Method: O26 was produced in a one-proton knockout reaction from F27 and the
O24+n+n decay products were measured using the MoNA-Sweeper setup. The
three-body correlations from the O26 ground-state resonance decay were
extracted. The experimental results were compared to Monte Carlo simulations in
which the resonance energy and decay mechanism were varied.
Results: The measured three-body correlations were well reproduced by the
Monte Carlo simulations but were not sensitive to the decay mechanism due to
the experimental resolutions. However, the three-body correlations were found
to be sensitive to the resonance energy of O26. A 1{\sigma} upper limit of 53
keV was extracted for the ground-state resonance energy of O26.
Conclusions: Future attempts to measure the three-body correlations from the
ground-state decay of O26 will be very challenging due to the need for a
precise measurement of the O24 momentum at the reaction point in the target
Search for unbound 15Be states in the 3n+12Be channel
15Be is expected to have low-lying 3/2+ and 5/2+ states. A first search did
not observe the 3/2+ [A. Spyrou et al., Phys. Rev. C 84, 044309 (2011)],
however, a resonance in 15Be was populated in a second attempt and determined
to be unbound with respect to 14Be by 1.8(1) MeV with a tentative spin-parity
assignment of 5/2+ [J. Snyder et al., Phys. Rev. C 88, 031303(R) (2013)].
Search for the predicted 15Be 3/2+ state in the three-neutron decay channel. A
two-proton removal reaction from a 55 MeV/u 17C beam was used to populate
neutron-unbound states in 15Be. The two-, three-, and four-body decay energies
of the 12Be + neutron(s) detected in coincidence were reconstructed using
invariant mass spectroscopy. Monte Carlo simulations were performed to extract
the resonance and decay properties from the observed spectra. The low-energy
regions of the decay energy spectra can be described with the first excited
unbound state of 14Be (E_x=1.54 MeV, E_r=0.28 MeV). Including a state in 15Be
that decays through the first excited 14Be state slightly improves the fit at
higher energies though the cross section is small. A 15Be component is not
needed to describe the data. If the 3/2+ state in 15Be is populated, the decay
by three-neutron emission through 14Be is weak, less than or equal to 11% up to
4 MeV. In the best fit, 15Be is unbound with respect to 12Be by 1.4 MeV
(unbound with respect to $14Be by 2.66 MeV) with a strength of 7%.Comment: 6 pages, 5 figures, accepted in Physical Review
Spectroscopy of neutron-unbound F
The ground state of F has been observed as an unbound resonance
keV above the ground state of F. Comparison of this
result with USDA/USDB shell model predictions leads to the conclusion that the
F ground state is primarily dominated by -shell configurations. Here
we present a detailed report on the experiment in which the ground state
resonance of F was first observed. Additionally, we report the first
observation of a neutron-unbound excited state in F at an excitation
energy of keV.Comment: 10 pages, 11 figures, Accepted for publication in Phys. Rev.
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