The approach to daylighting by scale models and sun and sky simulators: A case study for different shading systems

At the Daylighting Laboratory of the Politecnico di Torino a facility, which consists of a sun simulator and a sky scanning simulator, allows daylighting simulations to be made inside scale models for both research and design purposes. Photometric data and digital images of the luminous environment are the results that are obtained. The “sky” covers one-sixth of the vault, while the “sun” is fixed: therefore the model is rotated to reproduce the entire vault and rotated and tilted to reproduce the relative sun–Earth position.     

Thermotropic glass with active dimming control for solar shading and daylighting

The effectiveness of an autonomous responsive dimming (thermotropic) glass panel fabricated with a transparent heating layer and an electrochromic layer to provide additional active dimming control is examined through preliminary experiments and simulations. Thermotropic glass consists of two panes of glass sandwiching a polymer gel that undergoes a transition from clear to cloudy at a threshold temperature. Winter temperatures can thus prevent the glass from dimming when required for solar shading. With appropriate control of the heating layer, however, the performance of the panel with respect to office solar-shading requirements is demonstrated to be superior to that without the heating layer, despite the simplicity of the system. The configuration requires relatively low electric power, utilizing solar radiation energy to maintain the cloudy state as required. In a different approach, application of electrochromic layer for active dimming control is proposed and verified in various aspects with wavelength characteristics considering simulation.     

An analysis of daylighting performance for office buildings in Hong Kong

Daylighting has often been recognized as a useful source of energy savings and visual comforts in buildings. Occupants expect good daylight in their working spaces. The quality and quantity of natural light entering a building depend on both internal and external factors. In Hong Kong, commercial building accounts for the major building energy use and electric lighting is one of the major electricity-consuming items. This paper studies the daylighting performance and energy implications for office buildings. A total of 35 commercial buildings have been selected in the survey. Key building parameters affecting daylighting designs are presented. Two typical office blocks were further analysed based on a lighting simulation program. The daylighting performance was evaluated in terms of daylight factor, room depth and glare index. It has been found that the daylighting performance for office buildings is quite effective. About one-third of the office areas that are near the perimeter regions have an average daylight factor of 5%. For inner region of deep plan offices, some innovative daylighting systems such as light redirecting panels and light pipe could be used to improve the daylighting performance. In general, the office building envelop designs are conducive to effective daylighting and proper daylight linked lighting controls could save over 25% of the total electric lighting use.     

Overview and new developments in optical daylighting systems for building a healthy indoor environment

Optical daylighting technology can deliver natural light to a space in a building where daylight is limited. This study gives an overview of two optical daylighting systems for capturing natural light: light pipe systems and mirror sunlighting systems. The literature on optical system theories and developments is identified and commercial products for optical daylighting systems on the market are described. By using a survey of major applications for optical daylighting systems, this study provides practical advice to building designers and researchers and also shows a light pipe system and a mirror sunlighting system developed from this investigation as well as an evaluation of their performance. The evaluation measured the illuminance of the two optical systems installed in a test room and a living room. This study concluded that optical daylighting systems can provide adequate visual comfort and can save energy if they are carefully designed.     

An internal assessment of the thermal comfort and daylighting conditions of a naturally ventilated building with an active glazed facade in a temperate climate

An active facade is often used to promote the flow of air through a building, however in order to ensure that this process is effective the facade should face a southerly orientation. This means that not only solar energy is transferred across the glazing but in sunny periods shading is needed to prevent excess brightness levels occurring on the working areas where it may result in the luminance distributions not complying with current lighting requirements. The building investigated is located in Sheffield, England and is one of the University of Sheffield's recently built green buildings. It has a high thermal mass which is used to promote the use of night cooling. This paper reports the initial findings of an internal assessment of the thermal comfort and daylighting conditions in such a building. The results have indicated that such designs are to be commended for their passive use of solar energy and can provide a high quality working environment.     

建筑节能相变材料应用研究现状及发展

相变材料在建筑行业中的应用是一项降低建筑能耗的重要措施。本文介绍了建筑节能相变材料的定义、性能特点及分类,分析了建筑节能相变材料的国内外应用研究现状,并总结出建筑节能相变材料应用研究亟待解决问题,提出了相变材料的应用发展趋势,进而为相变材料在建筑行业中降低能耗的应用提供参考。     

Characterisation of the materials used in the construction of the Noto Cathedral

After the partial collapse of the Cathedral of Noto, the authors were required to carry out an extensive on site and laboratory investigation in order to support the designers of the Cathedral reconstruction to check the possibility of preserving the parts which are still standing and to choose the right solutions and the most compatible materials for the reconstruction. The tests carried out in laboratory in order to characterise the chemical, physical and mechanical properties of the original materials are described and their results discussed.     

Involving interested parties: application of analysis and planning tools

A model that explains the relationship between a project and its social environments is described. Tools used in the analysis of the environment are discussed, and an example of their practical application is presented.     

Responding to sudden pollutant releases in office buildings: 1. Framework and analysis tools

We describe a framework for developing response recommendations to unexpected toxic pollutant releases in commercial buildings. It may be applied in conditions where limited building- and event-specific information is available. The framework is based on a screening-level methodology to develop insights, or rules-of-thumb, into the behavior of airflow and pollutant transport. A three-stage framework is presented: (1). develop a building taxonomy to identify generic, or prototypical, building configurations; (2). characterize uncertainty and conduct simulation modeling to predict typical airflow and pollutant transport behavior; and (3). rank uncertainty contributions to determine how information obtained at a site might reduce uncertainties in the model predictions. The approach is applied to study a hypothetical pollutant release on the first floor of a five-story office building. Key features that affect pollutant transport are identified and described by value ranges in the building stock. Simulation modeling provides predictions and uncertainty estimates of time-dependent pollutant concentrations, following a release, for a range of indoor and outdoor conditions. In this exercise, we predict concentrations on the fifth floor to be an order of magnitude less than on the first, coefficients of variation greater than 2, and information about the HVAC operation and window position most reducing uncertainty in predicted peak concentrations.     

Optimization of energy consumption in buildings with hydronic heating systems considering thermal comfort by use of computer-based tools

The paper deals with an optimization of parameters, which influence the energy and investment cost as well as the thermal comfort. The parameters considered in this study are: the insulation thickness of the building envelope, the supply-water temperature and the heat exchange area of the radiators. A combination of the building energy simulation software EnergyPlus ¹ and the generic optimization program GenOpt (see footnote 1) has been used for this purpose. The paper presents the application of a one-objective optimization algorithm solving the problems with two objectives, because the optimization algorithm is one-objective and the problem has two objectives, which are minimal total costs and satisfied thermal comfort. The total costs represent the sum of energy consumption and the investment costs. The thermal comfort is represented by Predicted Percentage of Dissatisfied (PPD) in this study. The optimization is used to determine the values of parameters that give the lowest sum of investment and energy cost, under the condition that the thermal comfort is satisfied. In addition, the optimization processes show the mutual influence of parameters on both the total cost and the thermal comfort.     

Modelling of cowl performance in building simulation tools using experimental data and computational fluid dynamics

Exhaust cowls are used in conjunction with hybrid ventilation systems to efficiently convert wind energy into negative pressure and thus minimize the electrical energy required by the extract fan. Yet the fact that cowl performance is largely dictated by operating conditions imposes particularly stringent demands on modelling. This paper demonstrates, by way of a concrete example, the need for and potential benefits of a new methodological approach to the modelling of cowls. The study focuses on a specific modelling strategy, applied within a building simulation program, for a cowl used in a hybrid ventilation system. The method is progressively simplified to produce four variants, which chiefly vary according to their level of detail and, hence, the associated modelling effort. Wind pressure coefficients at facade, above roof and in the cowl are needed for all model variants. Some of the investigated variants rely on CFD computations of airflow around the building to determine these values. This study uses the example of a single-family house (SFH) to identify those criteria requiring particular attention in the performance of CFD numerical flow analyses. All four variants are examined on the basis of this example to determine which simplifications to the model are appropriate and permissible without unduly compromising the accuracy of the results.     

Pre-versus post-occupancy evaluation of daylight quality in hospitals

The purpose of this study is to examine the effect of space occupancy on indoor daylight quality in hospitals. It assesses the effect of various design variables on the indoor daylight quality in King Abdullah University Hospital (KAUH) in Jordan. By conducting a comparative study on the indoor daylight quality of pre- and post-occupancy in patient wards, it was found that hospital occupancy is highly correlated with indoor daylight quality.     

The role of the PASLINK test cell in the modelling and integrated simulation of an innovative window

The SOLVENT window is an innovative glazing system concept that involves the use of a rotating frame, an absorptive glazing and a naturally ventilated vertical channel, in order to improve the balance between the visual comfort and the energy efficiency of windows.     

Evaluating visual comfort and performance of three natural lighting systems for deep office buildings in highly luminous climates

This work, part of a wider study, presents a qualitative and quantitative approach to evaluate daylighting systems for use in office buildings located in latitudes where natural luminous conditions throughout the year are of high solar radiation, as in Israel. Their widespread application in this kind of climate, where the excessive penetration of direct radiation can be a problem, is possible. They can produce a consequent improvement of working conditions and energy savings, yet this is not the case now.     

Experimental study and evaluation of latent heat storage in phase change materials wallboards

Phase change materials (PCM) can be applied in building envelops to conserve heat energy. Wallboards incorporated with PCM can automatically absorb indoor redundant heat, which can greatly reduce the load of HVAC systems and save electric energy. In experiments, a PCM wallboard room was constructed by attaching PCM wallboards, developed by incorporating about 26% PCM by weight into gypsum wallboards, to the surface of an ordinary wall. The transition temperature and latent heat of these PCM wallboards were tested by differential scanning calorimetry (DSC). The room testing was conducted to determine the latent heat storage of PCM wallboards. Through experiments, it could be proved that DSC can effectively predict the performance of a full-scale installation of PCM wallboards. Compared with an ordinary room, it was found that the PCM wallboard room could greatly reduce the energy cost of HVAC systems and transfer electric power peak load to valley.     

2009年全国墙体材料机械产品检验情况分析与评价

国家建筑材料工业建材机械产品质量监督检验测试中心于2009年3月中旬组成3个检验组,历时三个多月对全国墙体材料机械产品质量进行了委托检验,并对金融危机下企业受影响程度进行了摸底和产品质量调研,了解并掌握墙材机械发展趋势和产品质量状况,其目的就是规范市场质量行为,为广大消费者提供设备选型依据,为行业发展做好服务工作。检验结果分析与评价如下：     

理性评价土水对建筑材料的腐蚀性

本文认为,岩土工程勘察评价水和土对建筑材料的腐蚀性时,只靠规范查表是不够的。应注意场地的调查研究,注意当地经验的调查研究,注意数据和资料的积累。从认识腐蚀机制,认识腐蚀环境的复杂性及经验与规范相结合的综合评价等方面入手,摒弃盲目,提高评价的理性。     

Development and performance evaluation of natural thermal-insulation materials composed of renewable resources

Because energy efficiency in buildings will be evaluated not only based upon heating demand, but also according to the primary energy demand, the ecological properties of the building materials for the whole assessment has become essential. The demand for green building materials is rising sharply, especially insulating materials from renewable resources. The application of natural materials has become increasingly important as a consequence of the increasing need to conserve energy, use natural materials, incorporate architecture and construction into sustainable development processes, and the recently promulgated discussions on appropriate disposal of used insulation materials such as polystyrene (EPS).Due to the fact that natural materials are more sensitive to moisture, decomposition factors such as temperature, material moisture content, attacks by microorganisms, and possible decomposition of the material or shorter durability, it is necessary to evaluate the degradation rate of built-in materials and also determine their real in situ hygrothermal properties according to their moisture content, and volume changes.This paper describes the results of a research project carried out at the Vienna University of Technology and Brno University of Technology. The objective is to use jute, flax, and hemp to develop a new insulating material from renewable resources with comparable building physics and mechanical properties to commonly used insulations materials. All input components are varied in the tests. The impact of moisture content changes in relation to the rate of change of other properties was the focus of the investigation. The tests results show that the correct combination of natural materials is absolutely comparable with convectional materials.