共查询到18条相似文献,搜索用时 250 毫秒
1.
介绍了我国常用墙体和屋面动态热特性参数(反应系数、周期反应系数、Z传递函数系数)数据表的开发研究。将一种新的简单准确而易于编程实现的计算方法——频域回归方法,用来开发这些常用的动态热特性参数,同时描述了所编制数据表的组成和结构。本研究为我国采暖空调工程界的动态负荷计算及建筑全年能耗动态分析与评价提供了基础数据。 相似文献
2.
3.
提出一种便于工程设计应用的太阳能采暖房间热负荷动态计算方法。通过z传递函数分析墙体动态传热过程,根据编程计算所得的墙体传热量逐时结果,获得太阳能采暖房间热负荷系数。通过对不同朝向墙体以及不同墙体结构的计算后发现:墙体热容量越大,热负荷系数的曰变化幅度越小;同一结构,但不同朝向墙体的热负荷系数存在较大差别。 相似文献
4.
5.
严治军 《土木建筑与环境工程》1982,4(3)
本文引用工程控制理论中有关扰最与响应的离散化处理思想,研究墙体的得热及负荷的计算方法。从建立综合温度与墙体得热间的传递函数着手,导出传递函数系数 b_i、d_(?)、∑C_i 的计算式,并编制出通用电算程序。以大量实测数据为基础,根据最小二乘原理,经多元之回归,整理并解出墙体得热及其形成负荷间的传递函数系数 v_0、 V_1、 w_1,经与实测数据验证,推荐参考使用。最后整理成墙体负荷计算之简化公式,至此,完成了 Z 传递函数法求解墙体得热及其形成负荷之计算。 相似文献
6.
回顾了建筑空调负荷计算方法的历史,并对几种典型的计算方法谐波反应法、反应系数法、Z传递函数法、冷负荷温差(CLTD)/冷负荷系数(CLF)法及负荷模拟的主要思想和特点进行了综述,并对各空调负荷计算法在未来的发展进行了展望。 相似文献
7.
对上海交大《围护结构动态负荷传递函数模型合成的系统辨识法>读后感 总被引:1,自引:1,他引:0
质疑该文对得热与冷负荷两者关系的处理,认为文题不宜使用“动态负荷”一词。指出该文未能明确区分z—传递函数与z—传递函数系数,导致传递函数表达式的讹误,且传递函数系数计算阶数高达10一12,ASHRAE手册及30多年来工程实用领域,似无此高阶实例。 相似文献
8.
用于计算墙体动态得热的方法通常有反应系数法、带公比项的反应系数法和传递函数法。本文提出的方法比反应系数法收敛快,比带公比项的反应系数法准确,比传递函数法简单。1983年11月,日本东京大学教授松尾阳先生在重庆建工学院讲学时,曾提出最新的计算墙体得热的项别公比法,他的方法仅取两个项别数来计算,对厚实墙体来 相似文献
9.
10.
反应系数与传递系数的合成及室温计算 总被引:1,自引:0,他引:1
提出计算围护结构内侧空气温度的合成反应系数方法与Z传递函数系数方法,明显地简化了计算步骤,降低了计算量。给出了多壁面反应系数与传递系数的合成公式,并探讨了其数值特性,实例计算效果良好。 相似文献
11.
This paper presents a simple time domain calculation method to derive thermal response factors and conduction transfer conduction (CTF) coefficients of finite differential models for estimating transient heat transfer through building structures. It is developed on the basis of converting the matrix exponential function, which is a part of the solution of the state equation established from the finite differential equations of building finite differential models, to matrix polynomial. The thermal response factors and CTF coefficients can be easily derived from the matrix polynomial with simple arithmetic and integral in time domain. This method avoids the time-consuming root-finding process of conventional methods and the computation of all the internal temperature of the finite differential model, while utilizing the advantage of the thermal response factors/CTF coefficients which relate the desired outputs at a moment to the previous inputs through a set of coefficients. Various case studies were conducted to validate the performance of this time domain calculation method in calculating the thermal response factors and CTF coefficients of various order finite differential models. 相似文献
12.
基于诱发因素响应分析的滑坡位移预测模型研究 总被引:7,自引:3,他引:4
滑坡位移的变化除与其基础地质条件相关之外,更取决于诱发因素的动态作用。为建立滑坡位移动态变化与诱因变化的响应关系,采用时间序列分解预测模型,通过移动平均法将位移分解为趋势项及周期项。趋势项位移由边坡的势能和约束条件所决定,利用多项式位移函数进行拟合预测。周期项位移受库水位涨落和降雨等诱因的周期性动态作用而变化,选取当前月降雨量、累计前两月降雨量、月库水位高程变化量及年内总位移累计增量为影响因子,利用BP神经网络进行多变量位移预测。将各分项位移预测值叠加,从而得到总位移预测值。以三峡库区白水河滑坡为例,利用位移、降雨及库水位变化数据进行计算验证。结果表明,基于滑坡诱发因素和位移变化综合分析预测模型,可以较好地反映诱因动态变化对滑坡位移发展的关键作用,提高预测结果的精度和有效性。 相似文献
13.
《Energy and Buildings》2005,37(4):301-310
A method of derivation of the conduction z-transfer function coefficients from response factors, for three-dimensional wall assemblies, is described.Results of the conduction z-transfer function coefficients calculations are presented for clear walls and separated details which are listed in ASHRAE research project 1145-TRP: “Modeling Two- and Three-Dimensional Heat Transfer Through Composite Wall and Roof Assemblies in Hourly Energy Simulation Programs”. Resistances, three-dimensional response factors and so-called structure factors, have been computed using the finite-difference computer code HEATING 7.2. The z-transfer function coefficients were then derived from a set of linear equations, constituting relationships with the response factors, which were solved using the minimum-error procedure.Test simulations show perfect compatibility of the heat flux calculated using three-dimensional response factors and three-dimensional z-transfer function coefficients, derived from the response factors. 相似文献
14.
A simplified multi‐degree‐of‐freedom (MDOF) model is developed for estimation of seismic response of tall wall‐frame structures. By using the continuum technique for the structure and adopting the bilinear hysteretic model for material properties, procedure for the development of the simplified MDOF model is derived. The numerical study for a 20‐storey reinforced concrete (RC) wall‐frame structure is conducted to investigate the accuracy of seismic response predicted by the proposed model. Results from the nonlinear response history analyses based on the proposed MDOF model and the detailed structural model with member‐by‐member representation are compared and show very good agreement. The proposed simplified MDOF model is shown to provide a simple, efficient and accurate method for estimation of seismic performance of tall wall‐frame structures. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
15.
基于时间序列与PSO-SVR耦合模型的白水河滑坡位移预测研究 总被引:1,自引:0,他引:1
滑坡位移预测模型的选择及其参数的选取是滑坡位移预测中至关重要的2个问题,以往的模型在预测滑坡位移时具有诸多的限制和不足。以三峡库区白水河滑坡为研究对象,基于时间序列分析方法,分离提取出滑坡趋势性位移与周期性位移。前者主要受控于滑坡的内部因素(物质组成、地质构造、地形地貌等),可用最小二乘法对其进行多项式拟合并预测;后者是由外部影响因素(季节性降雨、库水位变动等)导致,取当月降雨量、双月降雨量、库水位高程、月间库水位变化量、双月库水位变化量和年间累计位移增量作为周期性位移的影响因子,提出采用可优化选参的粒子群优化算法(PSO)与支持向量机回归(SVR)相结合的方法对其进行预测;将各分位移预测值叠加得到累计位移预测值。运用多种方法进行分析对比,结果表明,基于时间序列与PSO-SVR耦合模型的滑坡位移预测精度要明显高于BP神经网络模型、网格搜索法优化的支持向量机模型(GS),其在滑坡位移预测中具有一定的理论基础和良好的应用前景。 相似文献
16.
Alternative approach to compute shear amplification in high‐rise reinforced concrete core wall buildings using uncoupled modal response history analysis procedure 下载免费PDF全文
Tahir Mehmood Pennung Warnitchai Munir Ahmed M.Irshad Qureshi 《The Structural Design of Tall and Special Buildings》2017,26(4)
The seismic response of the high‐rise reinforced concrete (RC) wall structures is really complicated as several vibration modes other than the fundamental mode normally contribute significantly to the response—commonly recognized as ‘higher mode effects’. Response spectrum analysis (RSA) procedure, which can account for higher mode effects, is usually employed to compute the seismic design demand for the high‐rise structures. Recent studies show that the inelastic seismic force demands obtained from the rigorous nonlinear response history analysis procedure are much larger than the seismic force design demands obtained from the code‐based RSA procedure for the high‐rise RC wall structures. Though, the nonlinear response history analysis procedure is widely accepted for its ability to provide the most accurate estimate of nonlinear seismic responses, the obtained responses are generally so complex that it is quite difficult for engineers to grasp the overall picture of the responses and gain some insight into them and use them to understand the cause of high seismic demands. Another important issue related to the nonlinear seismic response prediction of the high‐rise RC wall structures is the realistic and accurate numerical modeling of RC walls. In this study, a simplified but reasonably accurate procedure called the uncoupled modal response history analysis procedure is used to interpret the complex nonlinear behavior of high‐rise RC wall structures. Moreover, a finite element model based on modified compression field theory is employed for accurate numerical modeling of RC walls by incorporating the axial‐flexure‐shear interaction. This study, by making use of a better computer modeling approach and an in‐depth analysis by modal decomposition, aims to resolve some of the unanswered questions regarding realistic prediction of nonlinear seismic demands of high‐rise structures. 相似文献
17.
Solomon SB 《The Science of the total environment》2001,272(1-3):303-313
A two-screen sampler (an effective dosimeter), with a collection efficiency matched to the particle size response of the radon progeny dose conversion factors (DCF), obtained from the ICRP respiratory tract model as implemented in the computer code RADEP, has been developed to assess the inhalation dose from exposure to radon progeny. In order to evaluate the performance of this sampler, the second stage of a six-stage wire screen diffusion battery was designed to operate as an Effective Dosimeter. This hybrid system allowed two methods for the determination of the radon progeny DCF. For the first method, the activity size distributions, measured using the diffusion battery, were used to obtain a size-weighted DCF. A second determination of DCF was obtained directly from the fraction collected by the Effective Dosimeter. The hybrid diffusion battery was used to measure radon progeny in the Fairy Cave, Buchan, Victoria at 20-min intervals over a 30-h period. This cave had radon concentrations exceeding 2000 Bq m(-3), with low aerosol concentration and low ventilation rates. The measurements were analysed for the radon progeny PAEC, the activity size distribution, the size-weighted DCF and the effective dosimeter collected fraction. The Effective Dosimeter DCFs were determined from the collected fraction using firstly a simple linear function and then using a more complex polynomial function to correct for residual errors. For the linear factor alone, the calculated Effective Dosimeter DCFs were on average 11% lower than the equivalent size-weighted DCF values. The agreement using the polynomial function was improved markedly, with a linear regression of the DCF yielding a fitted ratio of 0.965, with an R value of 0.99. For this study, the use of the ICRP conversion convention to estimate the occupational exposure to the tour guides working in the Fairy Cave would under estimate the effective dose by up to a factor of 2. 相似文献
18.
《Journal of Building Performance Simulation》2013,6(5):719-727
The purpose of this article is to present and validate a computationally efficient numerical approach for the calculation of the ground-coupled heat transfer in buildings with periodic boundary conditions. When the boundary conditions of the heat transfer problem are described by periodic functions, it is possible to consider the transient state problem as a quasi-stationary problem with considerable savings in terms of computational time. The method is presented in detail from a mathematical point of view, together with a validation for two simple cases of slab-on-grade thermal losses, four comparisons with the ISO 13370:2007 procedure, a case with a complex shape and an evaluation of the computational efficiency. 相似文献