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Chinese prototype building models for simulating the energy performance of the nationwide building stock

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Building Simulation 2023年第8期16卷 1559-1582页

作者： Jingjing An Yi Wu Chenxi Gui Da Yan School of Environment and Energy engineering Beijing University of Civil Engineering and ArchitectureBeijingChina Building Energy Research Center School of ArchitectureTsinghua UniversityBeijingChina

Building energy modeling(BEM)has become increasingly used in building energy conservation *** building models are developed to represent the typical urban building characteristics of a specific building type,meteorological conditions,and construction *** study included four residential buildings and 11 commercial buildings to represent nationwide building types in *** consideration of five climate zones and different construction years corresponding to national standards,a total of 151 prototype building models were *** building envelope properties,occupancy and energy-related behaviors,and heating,ventilation,and air-conditioning(HVAC)system characteristics were defined according to the corresponding building energy efficiency design standards,HVAC design standards,and through other sources,such as questionnaire surveys,on-site measurements,and literature,which reflect the real situation of existing buildings in *** on the developed prototype buildings,a large database of 9225 models in 270 cities was further developed to facilitate users to simulate building energy in different *** conclusion,the developed prototype building models can represent realistic building characteristics and construction practices of the most common residential and commercial buildings in China,serving as an important foundation for *** models can be used for analyses related to building energy conservation research on typical individual buildings,including energy-saving technologies,advanced controls,and new policies,and providing a reference for the development of building energy codes and standards.

关键词： prototype building models building stock modeling Chinese building building performance simulation energy conservation

Homogenization Function of Microchannel on Heat Absorber with Compound Parabolic Concentrator

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Journal of Thermal Science 2022年第6期31卷 2022-2031页

作者： WANG Xueqing WU Haifeng MA Yusen WANG Suilin XU Rongji beijing engineering Research Center of Sustainable Energy and Buildings Beijing University of Civil Engineering and ArchitectureBeijing 100044China

Microchannels offer unique advantages on heat transfer performance. In this paper, microchannels are applied to the compound parabolic concentrator(CPC) system. A multi-physical field coupling model based on Finite Element Method is proposed to investigate the homogenization effect of the microchannel heat absorber on the CPC non-uniform concentration. The energy conversion process from optics to heat is simulated using TracePro software, and the heat transfer processes in the microchannel are computed by Fluent using user defined functions(UDF). It is found that the microchannels behave well on weakening the influence of the nonuniformity solar heat flux on the performance of the CPC. The temperature nonuniformity of the outlet section is less than 10^(-3) in the direction of fluid flow caused by the microchannel, although the maximum surface heat flux inhomogeneity of the microchannel reaches 2.3. The peak value of the heat flux on the surface of the absorber changes from double peak to single peak, and moves to the edge, resulting in more uneven heat flux distribution with the increase of the incident angle within the acceptance semi-angle of the CPC. The result of TracePro clearly shows that when the concentration ratio is less than 5, the heat flux nonuniformity on the surface of the absorber decreases with the increase in concentration ratio. It was interestingly found that the temperature distribution of the heat transfer fluid has weak sensitivity to the changes of truncation ratio. This work provides a way to design a CPC solar collector.

关键词： solar energy microchannel compound parabolic concentrator multi-physical field

Simulation of artificial random field considering the temporal-spatial variation

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Acta Seismologica Sinica(English Edition) 2002年第4期15卷 425-430页

作者： NI Yong-jun (倪永军) ZHU Xi (朱晞) College of civil engineering and architecture Northern Jiaotong University Beijing 100044 China College of Civil Engineering and Architecture Northern Jiaotong University Beijing 100044 China

An apparent wave velocity varying with the frequency of seismic wave was adopted rather than an arbitrary one. The phase difference spectrum was introduced to consider the non-stationary properties of frequency contents in simulating artificial random field. The non-stationary random field on hard site considering the temporal-spatial variation was simulated by the way of spectral representation method. This random field can be used as the input of earthquake ground motion of the seismic response analysis of large-span spatial structures considering the effect of multi-supported excitation.

关键词： artificial random field apparent wave velocity phase difference spectrum

INFERENCE FOR REPEATED MEASURES MODELS UNDER HETEROSCEDASTICITY

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Journal of Systems Science & Complexity 2012年第6期25卷 1158-1170页

作者： Weiyan MU Xingzhong XU Science School Beijing University of Civil Engineering and Architecture School of Mathematics Beijing Institute of Technology

This paper considers a widely used mixed effects model in repeated measures under het- eroscedasticity. Hypotheses of the equality of the fixed effects and the simultaneous confidence intervals for all pair-wise differences are discussed. A generalized F-test has been proposed to test the equality of the fixed effects in the model, but simulation results for evaluating its performance have not been shown in the literature. Moreover, the generalized F-test cannot be used to deduce the simultaneous confidence intervals for all pair-wise differences of the fixed effects. The authors propose two new p-values to test the hypotheses of equality of the fixed effects and simultaneous confidence intervals of the differences of the effects based on the generalized pivotal quantities derived in this paper. The authors also compare the empirical performances of the proposed tests and the generalized F-test. The type I error rates and powers of these tests are evaluated using the Monte Carlo simulation. The simulation studies show that the generalized F-test does not perform well in terms of type I error rate under various sample size and parameter combinations. However, the type I error probabilities of the proposed tests are always close to the nominal value. It can also be seen that the simultaneous confidence intervals perform well.

关键词： Generalized p-values heteroscedasticity mixed effect repeated measures models simul-taneous confidence intervals.

Foundation Treatment in Urban Underground engineering Using Big Data Analysis for Smart City Applications

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Computer Modeling in engineering & Sciences 2022年第7期132卷 153-172页

作者： Fei Liu Yunkai Zhang Jian Zhang School of civil and Transportation engineering Beijing University of Civil Engineering and ArchitectureBeijing102616China beijing Advanced Innovation Center for Future Urban Design Beijing102616China School of Science Beijing University of Civil Engineering and ArchitectureBeijing102616China

A core element of the sustainable approach to global living quality improvement can now become the intensive and organized usage of underground *** is a growing interest in underground building and growth *** reduced consumption of electricity,effective preservation of green land,sustainable wastewater and sewage treatment,efficient reverse degradation of the urban environment,and reliable critical infrastructure management can improve the quality of *** the same time,technological innovations such as artificial intelligence(AI),cloud computing(CC),the internet of things(IoT),and big data analytics(BDA)play a significant role in improved quality of ***,this study aims to integrate the technological innovations in urban underground engineering to ensure a high quality of ***,this study uses big data analytics to carry out the status quo of foundation treatment and proposes a conceptual framework named the BDA with IoT on urban underground engineering(BI0T-UUE).This framework connects hidden features with various high-level sensing sources and practical predictive model characterization to lower building costs,productive infrastructure management,preparedness for disasters,and modern community smart *** IoT integration gives an optimum opportunity to work towards the functionality of‘‘digital doubles’’of secret infrastructure,both economical and scalable,with the increasing sophistication and tooling of the *** simulation analysis ensures the highest efficiency and cost-effectiveness of the underground engineering with a value of 96.54%and 97.46%.

关键词： Underground engineering internet of things big data analytics status quo economic and social smart city

Derivation of the work expression and discussion on the effective principle and the phase separation theorem in unsaturated soil

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Science China(Technological Sciences) 2008年第9期51卷 1530-1541页

作者： ZHAO ChengGang ZHANG XueDong School of civil engineering and architecture Beijing Jiaotong UniversityBeijing 100044China

Based on the balance equations for mass, linear momentum, energy in porous media theory and some hypotheses in unsaturated soil mechanics, an expression of the total deformation work W is derived, and with the help of the specific ex-pression of the work, the effective stress conjugated with the displacement of the soil skeleton is suggested by the authors, which has the similar form as the expressions proposed by Wheeler (2003) and some other researchers according to their experience and intuition, but the effective stress presented in this paper is derived on the basis of porous media theory and its assumptions, whose premise and hypothesis are clear. It is also pointed out that due to the complexity of the physical mechanism and various influencing factors, it is impossible in unsatu-rated soil mechanics to determine the deformation of solid skeleton by the effective stress only, like in the saturated soil mechanics. Besides, by using the expression of the deformation work and the free energy Aα for each phase, the applicability of the Phase Separation Principle proposed by Passman (1984) in unsaturated soil is discussed, and it is considered that the principle should not strictly apply to un-saturated soil mechanics.

关键词： total deformation work effective stress unsaturated soil Phase Separation Principle porous media theory

Generalized Centrosymmetric Matrix Algebras Induced by Automorphisms

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Algebra Colloquium 2022年第4期29卷 607-618页

作者： Huabo Xu School of Science Beijing University of Civil Engineering and Architecture Beijing 102616China

Let R be a ring with an automorphismφof order *** introduce the definition ofφ-centrosymmetric *** by M_(n)(R)the ring of all n X n matrices over R,and by Sn(φ,R)the set of all p-centrosymmetric n×n matrices over R for any positive integer *** show that Sn(φ,R)■M_(n)(R)is a separable Frobenius *** R is commutative,then Sn(φ,R)is a cellular algebra over the invariant subring R^(φ)of R.

关键词： φ-centrosymmetric matrix cellular algebra Frobenius extension

Spatially distributed damage in sandstone under stress-freeze-thaw coupling conditions

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Journal of Rock Mechanics and Geotechnical engineering 2022年第6期14卷 1910-1922页

作者： Lifeng Fan Yiding Fan Yan Xi Jingwei Gao College of architecture and civil engineering Beijing University of TechnologyBeijing100124China

In the present study,we tried to understand the spatially distributed damage in sandstone samples under the coupled stress-freeze-thaw(SFT)***,uniaxial compressive stresses(i.e.0 MPa,10 MPa,20 MPa,and 25 MPa)were applied to the samples,and then freeze-thaw(FT)cycles(0,8,16,and 24)were performed on the uniaxially stressed samples to realize the SFT ***,real-time CT scanning was conducted to observe the induced *** total porosity was introduced to quantitatively evaluate the damage *** local porosity variation,with the distance from the center of the sandstone sample,was analyzed to understand the spatial distribution of ***,the coupling effects of SFT on the damage gradient were *** results indicate that the porosity rises with FT cycles,and the applied stresses can accelerate the increase in *** damage increases exponentially with the distance from the center of the *** damage presents a spatial gradient distribution,not the commonly used uniform distribution in various *** damage gradient increases with FT cycles,and the increasing rate in damage gradient decreases at uniaxial stress of 0 MPa and 10 MPa first,but the increasing rate in damage gradient increases with FT cycles then at stress increasing to 20 MPa.

关键词： Rock damage Freeze-thaw(FT)cycles Uniaxial stress oupling effects

J/ψ pair hadroproduction at next-to-leading order in nonrelativistic-QCD at ATLAS

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Chinese Physics C 2024年第3期48卷 15-19页

作者：孙立平 School of Science Beijing University of Civil Engineering and ArchitectureBeijingChina

We present a complete study on the J/ψpair hadroproduction at next-to-leading order(NLO)in the nonrelativstic-QCD(NRQCD)framework with the pair of cc¯in either ^(3)S^([1])_(1) or ^(1)S^([8])_(0) fock *** found that the contribution of the ^(1)S^([8])_(0) channel at NLO is essential,and for ATLAS,the NRQCD results can describe the experimental data to a certain extent.

关键词： NRQCD next-to-leading order ATLAS fock state