Performance of EN ISO 13790 utilisation factor heat demand calculation method in a cold climate

The applicability of the utilisation factor method EN ISO 13790 is studied in modern Finnish buildings in the cold climate of Finland. The heat-demand results of EN ISO 13790 are compared against a validated dynamic simulation tool. It is shown that, with the default values of the numerical parameters of the utilisation factor, EN ISO 13790 gives in Finnish conditions as much as 46% higher or 59% lower heat demand of the building compared to the simulation tool, depending on the type of the building and its thermal inertia. The results of EN ISO 13790 can be calibrated for the residential buildings with the correct selection of the numerical parameters for Finnish conditions. With the new values of the parameters, the results are in good agreement in most cases; however, the maximum difference between the methods remained 29% for highly insulated residential buildings. For office buildings, heat demand was strongly underestimated in all the cases by the monthly method EN ISO 13790 regardless of the values of the parameters. The results of the study indicate that the monthly method EN ISO 13790 with new determined numerical parameters is reasonably applicable for residential buildings, but not applicable for office buildings. Therefore, the other methods of prEN 13790, i.e., simple hourly or detailed simulation methods, should be used for office buildings.     

Monthly average clear-sky broadband irradiance database for worldwide solar heat gain and building cooling load calculations

This paper establishes the formulation of a new clear-sky solar radiation model appropriate for algorithms calculating cooling loads in buildings. The aim is to replace the ASHRAE clear-sky model of 1967, whose limitations are well known and are reviewed. The new model is derived in two steps. The first step consists of obtaining a reference irradiance dataset from the REST2 model, which uses a high-performance, validated, two-band clear-sky algorithm. REST2 requires detailed inputs about atmospheric conditions such as aerosols, water vapor, ozone, and ground albedo. The development of global atmospheric datasets used as inputs to REST2 is reviewed. For the most part, these datasets are derived from space observations to guarantee universality and accuracy. In the case of aerosols, point-source terrestrial measurements were also used as ground truthing of the satellite data. The second step of the model consists of fits derived from a REST2-based reference irradiance dataset. These fits enable the derivation of compact, but relatively accurate expressions, for beam and diffuse clear-sky irradiance. The fitted expressions require the tabulation of only two pseudo-optical depths for each month of the year. The resulting model, and its tabulated data, are expected to be incorporated in the 2009 edition of the ASHRAE Handbook of Fundamentals.     

一种Flyback-Boost非隔离型高增益直流变换器

提出一种Flyback变换器与Boost变换器相结合的非隔离型高增益直流变换器。该变换器中的Flyback变换器变压器原边电感和Boost变换器电感共用,Flyback变换器的开关管和Boost变换器开关管共用,Flyback变换器的输出和Boost变换器的输出串联,变压器漏感能量能够回馈到Boost变换器的输出,从而获得高增益高效率特性。电路具有结构简单、开关器件电压应力减少的优点。详细分析了拓扑工作原理、电压增益与效率特性。制作了一台100kHz开关频率/80W负载/24V输入/200V输出的实验样机,样机在轻载下可达到91.6%的效率,实验波形验证了理论分析的正确性。     

基于非线性增益递归滑模的船舶轨迹跟踪动态面自适应控制

针对三自由度全驱动船舶存在模型不确定和未知外部环境扰动的情况,设计出一种基于非线性增益递归滑模的船舶轨迹跟踪动态面自适应神经网络控制方法.该方法综合考虑船舶位置和速度误差之间关系设计递归滑模面,引入神经网络对船舶模型不确定部分进行逼近,设计带σ-修正泄露项的自适应律对神经网络逼近误差与外界环境扰动总和的界进行估计,并应用一种非线性增益函数构造动态面控制律,选取李雅普诺夫函数证明了该控制律能够保证轨迹跟踪闭环系统内所有信号的一致最终有界性.最后,基于一艘供给船进行仿真验证,结果表明,船舶轨迹跟踪响应速度快、精度高,所设计控制器对系统模型参数摄动及外界扰动具有较强的鲁棒性.     

Low cost passive cooling system for social housing in dry hot climate

The low energy approach should be the key concept in any long-term strategy aiming to build sustainability. For Madrid climate, action should be taken to reduce energy demand for heating and cooling in residential buildings.The performance of a passive cooling system was developed as a part of design work for the project of a low cost residential building. The passive cooling systems incorporate a solar chimney and precool the air by using the sanitary area of the building. The natural ventilation is enhanced with the help of the solar chimney and fresh air is cooled down by circulation within the sanitary area. The application of this system to the living rooms of a low cost residential building was evaluated and implemented. This cooling system incorporated to a residential building is the third prototype developed since 1991 by the designers. A model was developed to allow to predict the temperature of the air in the living room. The performance of the passive cooling system was evaluated based on the energy balance for a typical summer day.To reduce the energy demand in winter, a new design and window orientation has been developed and evaluated using DOE-2 simulation tool. The building has been constructed and monitored during 2006-2007.     

基于增益调度的结构振动分布式反馈控制

使用多传感器和驱动器控制简支板的振动.传感器和驱动器局部连接组成独立的闭环.在仿真中分别采用了点力驱动器和压电陶瓷驱动器.以极小化系统的总动能为目标,使用同步扰动方法对结构振动的分布式反馈增益进行最优调度.仿真结果表明,所提出的方法可以有效地抑制结构振动.     

浅析善意取得之"善意"

善意取得制度已被众多国家民法所确认,我国立法上未确立该项制度,但其已为我国司法实践所采纳。善意取得的成立以受让人的“善意”为基本前提。关于“善意”的范畴,历史起源和现代立法的规定不尽一致：对善意、恶意的判断标准,也存在着“消极观念说”和“积极观念说”两种观点;“善意”的准据时点的不同认定也成为判断行为人“善意”的重要因素。     

一种基于语义距离的关键词获取方法

关键词作为文本的概要信息,是信息检索,特别是针对海量Web信息处理的基础。由于手工分配关键词是一项耗时性的工作,因此不需要训练集的非监督关键词获取方法研究受到了关注。本文以语义聚类为模型,以词在给定语境和词义本身两种语义距离的计算为基础,给出一种关键词获取算法。实验结果表明,该算法得到较好的查准率。     

Auto CAD在建筑创作中利与弊的研究

介绍AutoCAD发展的概况以及在建筑创作中的作用,并根据建筑创作的特点,指出运用 计算机技术进行建筑创作时的利与弊,使人们能够正确地对待和运用这一新技术.     

Climatic and internal factors affecting future UK office heating and cooling energy consumptions

There is a large consensus concerning the expected trend, if not the magnitude of change, of the UK climate in the coming decades [Climate Change 2007: Impacts, Adaptation and Vulnerability, Intergovernmental Panel on Climate Change, April 2007]. This study aims to quantify how such changes will have a direct effect on heating and cooling energy use in future office environments (i.e. by the year 2030). When considering future offices, it is also necessary to account for a change in the small power and lighting equipment being used, in this case by assuming an improved efficiency in both categories. This will also have a significant effect on the balance of heating and cooling an office. Furthermore, the subtle effect of a change in location within the UK can affect results further, with northern cities having substantially higher heating loads (and lower cooling loads) than southern locations. Such factors can influence approaches towards reducing future office energy demands and, in some cases, be the difference between a heating-dominated or cooling-dominated building. This study should also inform future choices for supplying energy to office buildings, in particular microgeneration options. It confirms the importance of dealing with demand-side changes before assessing the supply-side opportunities, with buildings having very different heating and cooling needs post-refurbishment. The study also highlights the importance, and possibilities, of adapting to future climates, and the benefits of promoting heating-dominated buildings instead of cooling-dominated.