Automated Calibration Tool for Building Energy Models
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32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
SEARCH · Engineering Papers
Results for “ENERGY MODELS”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Fast ignition: Dependence of the ignition energy on source and target parameters for particle-in-cell-modelled energy and angular distributions of the fast electrons
The energy and angular distributions of the fast electrons predicted by particle-in-cell (PIC) simulations differ from those historically assumed in ignition designs of the fast ignition scheme. Using a particular 3D PIC calculation, we show how the ignition energy varies as a function of source-fuel distance, source size, and density of the pre-compressed fuel. The large divergence of the electron beam implies that the ignition energy scales with density more weakly than the ρ{sup −2} scaling for an idealized beam [S. Atzeni, Phys. Plasmas 6, 3316 (1999)], for any realistic source that is at some distance from the dense deuterium-tritium fuel. Due to the strong dependence of ignition energy with source-fuel distance, the use of magnetic or electric fields seems essential for the purpose of decreasing the ignition energy.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Extending the Coyote emulator to dark energy models with standard w {sub 0}- w {sub a} parametrization of the equation of state
We discuss an extension of the Coyote emulator to predict non-linear matter power spectra of dark energy (DE) models with a scale factor dependent equation of state of the form w = w {sub 0}+(1- a ) w {sub a} . The extension is based on the mapping rule between non-linear spectra of DE models with constant equation of state and those with time varying one originally introduced in ref. [40]. Using a series of N-body simulations we show that the spectral equivalence is accurate to sub-percent level across the same range of modes and redshift covered by the Coyote suite. Thus, the extended emulator provides a very efficient and accurate tool to predict non-linear power spectra for DE models with w {sub 0}- w {sub a} parametrization. According to the same criteria we have developed a numerical code that we have implemented in a dedicated module for the CAMB code, that can be used in combination with the Coyote Emulator in likelihood analyses of non-linear matter power spectrum measurements. All codes can be found at https://github.com/luciano-casarini/pkequal.
79 ASTRONOMY AND ASTROPHYSICS↗
SBIR Phase I Final Technical Report: Tools for Auto-calibration of Building Energy Models and Fault Detection Topic: 2b
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42 ENGINEERING↗
Data-driven building energy modeling with feature selection and active learning for data predictive control
Three gaps impede the development of cost-effective and accurate data-driven building energy modeling/models (DBEM) for energy forecasting and predictive control strategies. Gap 1: data bias is common in building operation data, but this topic is hardly studied in DBEM; Gap 2: high data dimensionality is common in DBEM, but a systematic and scalable methodology is lacking to solve the problem; Gap 3: the interactions between data bias and high dimensionality have not been systematically studied for DBEM and predictive control in buildings. In this work, to address the three gaps mentioned above, we develop a framework that integrates active learning and feature selection for DBEM used for whole building data predictive control (or DPC, which is a branch of model predictive control). The framework provides a systematic methodology and automatic workflow that starts with raw data from building automation systems to the establishment of data-driven energy models for DPC controllers. The developed strategies and framework are evaluated in a virtual testbed based on EnergyPlus and BCVTB. Improved performance and reduced computational complexity are observed from the DBEM built with the developed framework, as well as the DPC controller based on that DBEM, indicating the effectiveness of the developed framework.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
A new equation of state for dark energy model
A new parameterization for the dark energy equation of state(EoS) is proposed and some of its cosmological consequences are also investigated. This new parameterization is the modification of Efstathiou' dark energy EoS parameterization. w(z) is a well behaved function for z >> 1 and has same behavior in z at low redshifts with Efstathiou' parameterization. In this parameterization there are two free parameter w{sub 0} and w{sub a}. We discuss the constraints on this model's parameters from current observational data. The best fit values of the cosmological parameters with 1σ confidence-level regions are: Ω{sub m} = 0.2735{sup +0.0171}{sub −0.0163}, w{sub 0} = −1.0537{sup +0.1432}{sub −0.1511} and w{sub a} = 0.2738{sup +0.8018}{sub −0.8288}.
79 ASTRONOMY AND ASTROPHYSICS↗
Building America Case Study: Community-Scale Energy Modeling (Fact Sheet)
IBACOS analyzed pre-retrofit daily utility data to sort homes by energy consumption, allowing for better targeting of homes for physical audits. Following ASHRAE Guideline 14 normalization procedures, electricity consumption of 1,166 all electric production-built homes' was modeled. The homes were in two communities--one built in the 1970s and the other in the mid-2000s.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Energy Models for One-Carrier Transport in Semiconductor Devices
Moment models of carrier transport, derived from the Boltzmann equation, made possible the simulation of certain key effects through such realistic assumptions as energy dependent mobility functions. This type of global dependence permits the observation of velocity overshoot in the vicinity of device junctions, not discerned via classical drift-diffusion models, which are primarily local in nature. It was found that a critical role is played in the hydrodynamic model by the heat conduction term. When ignored, the overshoot is inappropriately damped. When the standard choice of the Wiedemann-Franz law is made for the conductivity, spurious overshoot is observed. Agreement with Monte-Carlo simulation in this regime required empirical modification of this law, or nonstandard choices. Simulations of the hydrodynamic model in one and two dimensions, as well as simulations of a newly developed energy model, the RT model, are presented. The RT model, intermediate between the hydrodynamic and drift-diffusion model, was developed to eliminate the parabolic energy band and Maxwellian distribution assumptions, and to reduce the spurious overshoot with physically consistent assumptions. The algorithms employed for both models are the essentially non-oscillatory shock capturing algorithms. Some mathematical results are presented and contrasted with the highly developed state of the drift-diffusion model.
Jerome, Joseph W.↗
Institutional heat wave analysis by building energy modeling fleet and meter data
Not Available
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Comparison of Building Energy Modeling Programs: HVAC Systems
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32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Constraints on the sum of the neutrino masses in dynamical dark energy models with w ( z ) ≥ - 1 are tighter than those obtained in Λ CDM
In this work, we explore cosmological constraints on the sum of the three active neutrino masses M ν in the context of dynamical dark energy (DDE) models with equation of state (EoS) parametrized as a function of redshift z by w(z) = w 0 + w a z/(1 + z), and satisfying w(z) ≥ -1 for all z. We make use of cosmic microwave background data from the Planck satellite, baryon acoustic oscillation measurements, and supernovae Ia luminosity distance measurements, and perform a Bayesian analysis. We show that, within these models, the bounds on M ν do not degrade with respect to those obtained in the Λ CDM case; in fact, the bounds are slightly tighter, despite the enlarged parameter space. We explain our results based on the observation that, for fixed choices of w 0 , w a such that w(z) ≥ - 1 (but not w = -1 for all z), the upper limit on M ν is tighter than the Λ CDM limit because of the well-known degeneracy between w and M ν . The Bayesian analysis we have carried out then integrates over the possible values of w 0 - w a such that w (z) ≥ -1, all of which correspond to tighter limits on M ν than the Λ CDM limit. We find a 95% credible interval (C.I.) upper bound of M ν < 0.13 eV . This bound can be compared with the 95% C.I. upper bounds of M ν < 0.16 eV , obtained within the Λ CDM model, and M ν < 0.41 eV, obtained in a DDE model with arbitrary EoS (which allows values of w < -1). Contrary to the results derived for DDE models with arbitrary EoS, we find that a dark energy component with w(z) ≥ -1 is unable to alleviate the tension between high-redshift observables and direct measurements of the Hubble constant H 0 . Lastly, in light of the results of this analysis, we also discuss the implications for DDE models of a possible determination of the neutrino mass ordering by laboratory searches.
79 ASTRONOMY AND ASTROPHYSICS↗
Simple implementation of general dark energy models
We present a formalism for the numerical implementation of general theories of dark energy, combining the computational simplicity of the equation of state for perturbations approach with the generality of the effective field theory approach. An effective fluid description is employed, based on a general action describing single-scalar field models. The formalism is developed from first principles, and constructed keeping the goal of a simple implementation into CAMB in mind. Benefits of this approach include its straightforward implementation, the generality of the underlying theory, the fact that the evolved variables are physical quantities, and that model-independent phenomenological descriptions may be straightforwardly investigated. We hope this formulation will provide a powerful tool for the comparison of theoretical models of dark energy with observational data.
79 ASTRONOMY AND ASTROPHYSICS↗
Integration of Electric Vehicle Charging Loads in Residential Building Stock Energy Modeling
The rapid adoption of electric vehicles (EVs) has resulted in significant new household electric loads that have the potential to change how energy costs are incurred by homeowners and the landscape of utility operations and energy infrastructure. Whereas adoption patterns and magnitudes of residential building and EV charging loads are influenced by distinct factors, the loads themselves are tightly coupled with the behavior of the individual occupants and EV owners.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Isotropic and anisotropic dark energy models
In this review we discuss the evolution of the universe filled with dark energy with or without perfect fluid. In doing so we consider a number of cosmological models, namely Bianchi type I, III, V, VI{sub 0}, VI and FRW ones. For the anisotropic cosmological models we have used proportionality condition as an additional constrain. The exact solutions to the field equations in quadrature are found in case of a BVI model. It was found that the proportionality condition used here imposed severe restriction on the energy-momentum tensor, namely it leads to isotropic distribution of matter. Anisotropic BVI{sub 0}, BV, BIII and BIDE models with variable EoS parameter ω have been investigated by using a law of variation for the Hubble parameter. In this case the matter distribution remains anisotropic, though depending on the concrete model there appear different restrictions on the components of energy-momentum tensor. That is why we need an extra assumption such as variational a law for the Hubble parameter. It is observed that, at the early stage, the EoS parameter v is positive i.e. the universe was matter dominated at the early stage but at later time, the universe is evolving with negative values, i.e., the present epoch. DE model presents the dynamics of EoS parameter ω whose range is in good agreement with the acceptable range by the recent observations. A spatially homogeneous and anisotropic locally rotationally symmetric Bianchi-I space time filled with perfect fluid and anisotropic DE possessing dynamical energy density is studied. In the derived model, the EoS parameter of DE (ω{sup (de)}) is obtained as time varying and it is evolving with negative sign which may be attributed to the current accelerated expansion of Universe. The distance modulus curve of derived model is in good agreement with SNLS type Ia supernovae for high redshift value which in turn implies that the derived model is physically realistic. A system of two fluids within the scope of a spatially flat and isotropic FRW model is studied. The role of the two fluids, either minimally or directly coupled in the evolution of the dark energy parameter, has been investigated. In doing so we have used three different ansatzs regarding the scale factor that gives rise to a variable decelerating parameter. It is observed that, in the non-interacting case, both the open and flat universes can cross the phantom region whereas in the interacting case only the open universe can cross the phantom region. The stability and acceptability of the obtained solution are also investigated.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Stable large-scale perturbations in interacting dark-energy model
It is found that the evolutions of density perturbations on the super-Hubble scales are unstable in the models with dark-sector interaction Q proportional to the energy density of cold dark matter (CDM) and constant equation of state parameter of dark energy (DE). In this paper, to avoid the instabilities, we suggest a new covariant model for the energy-momentum transfer between DE and CDM. Then we show that the the large-scale instabilities of curvature perturbations can be avoided in a universe filled only by DE and CDM. Furthermore, by including the additional components of radiation and baryons, we calculate the dominant non-adiabatic modes in the radiation era and find that the modes grow in the power law with exponent at the order of unit.
79 ASTRONOMY AND ASTROPHYSICS↗
A parametrization of the growth index of matter perturbations in various Dark Energy models and observational prospects using a Euclid-like survey
We provide exact solutions to the cosmological matter perturbation equation in a homogeneous FLRW universe with a vacuum energy that can be parametrized by a constant equation of state parameter w and a very accurate approximation for the Ansatz w(a) = w{sub 0}+w{sub a}(1−a). We compute the growth index γ = log f(a)/log Ω{sub m}(a), and its redshift dependence, using the exact and approximate solutions in terms of Legendre polynomials and show that it can be parametrized as γ(a) = γ{sub 0}+γ{sub a}(1−a) in most cases. We then compare four different types of dark energy (DE) models: wΛCDM, DGP, f(R) and a LTB-large-void model, which have very different behaviors at z∼>1. This allows us to study the possibility to differentiate between different DE alternatives using wide and deep surveys like Euclid, which will measure both photometric and spectroscopic redshifts for several hundreds of millions of galaxies up to redshift z ≅ 2. We do a Fisher matrix analysis for the prospects of differentiating among the different DE models in terms of the growth index, taken as a given function of redshift or with a principal component analysis, with a value for each redshift bin for a Euclid-like survey. We use as observables the complete and marginalized power spectrum of galaxies P(k) and the Weak Lensing (WL) power spectrum. We find that, using P(k), one can reach (2%, 5%) errors in (w{sub 0},w{sub a}), and (4%, 12%) errors in (γ{sub 0},γ{sub a}), while using WL we get errors at least twice as large. These estimates allow us to differentiate easily between DGP, f(R) models and ΛCDM, while it would be more difficult to distinguish the latter from a variable equation of state parameter or LTB models using only the growth index.
79 ASTRONOMY AND ASTROPHYSICS↗