A neuro-fuzzy model for prediction of the indoor temperature in typical Australian residential buildings

The Masonry Research Group at The University of Newcastle, Australia has embarked on an extensive research program to study the thermal performance of common walling systems in Australian residential buildings by studying the thermal behaviour of four representative purpose-built thermal test buildings (referred to as ‘test modules’ or simply ‘modules’ hereafter). The modules are situated on the university campus and are constructed from brick veneer (BV), cavity brick (CB) and lightweight (LW) constructions. The program of study has both experimental and analytical strands, including the use of a neuro-fuzzy approach to predict the thermal behaviour. The latter approach employs an experimental adaptive neuro-fuzzy inference system (ANFIS) which is used in this study to predict the room (indoor) temperatures of the modules under a range of climatic conditions pertinent to Newcastle (NSW, Australia). The study shows that this neuro-fuzzy model is capable of accurately predicting the room temperature of such buildings; thus providing a potential computationally efficient and inexpensive predictive tool for the more effective thermal design of housing.     

Analysis of brick veneer walls on wood frame construction subjected to out-of-plane loads

Modern residential brick masonry veneer construction has been investigated by separate laboratory testing of corrugated sheet metal tie connections and full-scale solid brick veneer wall panels. Based on these experiments, detailed three-dimensional finite element (FE) models were developed, representing the full-scale brick veneer wall panel specimens, including nonlinear inelastic properties for the tie connections. Upon calibration, the FE wall panel models effectively captured the static and dynamic experimental brick veneer wall behaviors at different response levels (up to and including tie damage and even collapse). Some parametric studies were then carried out using the FE wall panel models to evaluate the effects of certain combinations of tie connections and layouts on the out-of-plane performance of brick veneer walls, subjected to static and dynamic loading.     

泡沫混凝土外墙的热工性能测试与分析

随着建筑能耗的不断增加以及能源危机的日益加剧,建筑节能变得尤为迫切。外墙是围护结构节能的重点。泡沫混凝土因良好的保温隔热性能被广泛应用于建筑工程中,但其在建筑外墙的应用还处于探索阶段。本文介绍了新型泡沫混凝土外墙的构造及性能特点,并通过实验对比分析了外保温墙体、实心砖墙体和泡沫混凝土墙体的保温隔热性能。实验结果显示,泡沫混凝土外墙的保温隔热性能远优于其他两种墙体,在空调状态下,其内表面的热流值仅为外保温墙体的30.4%,具有显著的节能效果。不仅如此,泡沫混凝土外墙更为轻质,其质量仅为外保温墙体的49.1%。     

The role of adaptive thermal comfort in the prediction of the thermal performance of a modern mixed-mode office building in the UK under climate change

Climate change is becoming a serious issue for the construction industry, since the time scales at which climate change takes place can be expected to show a true impact on the thermal performance of buildings and HVAC systems. In predicting this future building performance by means of building simulation, the underlying assumptions regarding thermal comfort conditions and the related heating, ventilating and air conditioning (HVAC) control set points become important. This article studies the thermal performance of a reference office building with mixed-mode ventilation in the UK, using static and adaptive thermal approaches, for a series of time horizons (2020, 2050 and 2080). Results demonstrate the importance of the implementation of adaptive thermal comfort models, and underpin the case for its use in climate change impact studies. Adaptive thermal comfort can also be used by building designers to make buildings more resilient towards change.     

Strength and thermal conductivity in lightweight building materials

Pumice can be used in bricks and concrete to produce lightweight building materials with high porosity, high thermal insulation and resistance to earthquake motion. The paper presents ongoing research to design a structural lightweight concrete and brick using Nevşehir pumice. The testing of four different brick types is reported. The density, thermal conductivity, compressive and tensile strengths and Young’s elastic modulus indicated that these lightweight materials had significant advantages as a construction material in earthquake-prone areas.      

仿古青砖贴面施工技术

阐述了仿古青砖贴面施工中易出现的质量问题及其所采取的技术措施,仿古青砖贴面干摆缝、仿丝缝、小砖缝及粘贴、扎丝挂贴的施工方法和质量控制要点,使仿古青砖贴面装饰的建筑墙面达到古建筑的装饰风格和效果.     

Modelling of wall heat transfer using modified conduction transfer function, finite volume and complex Fourier analysis methods

The original conduction transfer function (CTF) method (which was derived from the EnergyPlus source codes), and the present modified CTF method (which uses a higher order discretisation scheme for the surface heat flux as well as finer grids at the layer boundaries for multi-layer constructions) were used to calculate wall surface heat fluxes based on monitored wall surface temperatures as the inputs. At the same time, the finite volume method and the matrix method (based on the complex Fourier analysis) were also used for the numerical predictions. The matrix transfer method was updated to treat the non-linear long wave length thermal radiation and proved to be consistent with the results from the finite volume method for all wall types ranging from single-layer wall, two-layer wall with air gap, cavity brick wall and brick veneer wall. Numerical predictions using the matrix transfer method, the conduction transfer function method and the finite volume method were compared with the long period measurements for single- or multi-layer materials with and without air gaps. At the same time, CTF coefficients for modified CTF methods were tabulated and analysed for all computational cases in this study.     

Energy and cost evaluation of thermal bridge correction in Mediterranean climate

In the cold climate of continental Europe the correction of thermal bridges in buildings is a mandatory issue, as in these areas they produce not only heat losses but frequently also condensation and mould growth.In mild Mediterranean climate thermal bridges also cause an increase in energy consumption, but usually do not present condensation effects. In Italy, the current regulations for new buildings only recommend but do not impose the thermal bridge correction, which usually needs extra costs during construction and refurbishment phases.This paper presents a study on the effects of thermal bridges for two building types (terraced houses and semi-detached houses) and three current envelope solutions in Italian climate, which may be considered representative of mild Mediterranean climate. The buildings are characterised by reinforced concrete frameworks and clay block walls; the thermal performance of the envelopes complies with Italian regulations for new constructions. In a first step the impact of thermal bridges on both heating and cooling energy demand is studied; then the economic convenience of correcting such thermal bridges is assessed by calculating the discounted payback period referred to the additional costs of construction and refurbishment.     

Cool roofs impact on building thermal response: A French case study

The refurbishment of building roofs with cool selective coatings is already defined by some standards. Impacts on urban heat island (UHI) and thermal performance of buildings are well identified. In France, most of the developments on building thermal performances are focused on the building envelope insulation, especially for the winter energy performance, and the cool roof technique as a part of the solution for summer conditions is not well established. This passive technique for cooling the cities and indoor environments has a performance depending on the climatic location and constructions morphology. In this paper, we focus on a case study in Poitiers (France): a cool roof for a low-rise building (public housing), without any cooling active system.The performance of the cool coating is detailed through experimental results, completed by a dynamic simulation work on the studied building. In a first part, the case study is presented; the surface temperatures and the climatic conditions were monitored indoor and outdoor. Then, a dynamic simulation for the summer period is compared to the experimental results. This audit study of the actual case study permits the analysis extension of thermal condition in order to compare the performance of the envelope toward the cool roof. This first case study analysis will help understanding the cool roof potential and limitations in a French context. These results will have to be projected for various construction typologies in order to help its development in the different climatic regions. It will be also a part of different European climate first comparison through the work of the EU cool roof project.     

外墙外保温技术在小高层楼宇中的应用

外墙外保温是建筑节能的重要措施之一。在小高层楼宇中，应用了加气混凝土砌块加挤塑板的外墙外保温体系，采用挤塑板作为保温隔热材料，以黏结剂粘贴为主、机械锚固为辅进行安装。介绍了这种体系的构造做法及施工工艺，并应用DeST-h软件对建筑能耗进行模拟。应用该体系后，节能率（相对240砖墙）达到46．12％，值得在徐州地区大力推广应用。     

Humidity control effect of vapor-permeable walls employing hygroscopic insulation material

Airtight construction and high-performance thermal insulation materials are commonly considered important building features to enhance indoor thermal comfort while reducing thermal load. However, when water vapor is generated in such airtight indoor spaces, it cannot be discharged to the outside, causing interstitial condensation and subsequent intrusion of moisture into the walls. Hygroscopic building materials such as cellulose fiber insulation (CFI), characterized by high water capacity, are a potential countermeasure against such condensation. In this study, the humidity control performance of external walls containing CFI was evaluated using data measured inside a demonstration house and calculated by numerical simulations based on thermodynamic chemical potential theory. The changes in moisture adsorption and desorption were then evaluated for different wall constructions and different climate conditions using a parameter sensitivity analysis. Finally, the effective application of CFI to prevent interstitial condensation was confirmed by comparing different wall compositions.     

Seismic response of a new type of masonry tie used in brick veneer walls

One of the concerns with the conventional metal anchors that are used to tie the brick veneer to the backup portion of enclosure walls (e.g. masonry block) is the potential for corrosion. Corrosion reduces the load carrying capacity of such ties and this could lead to brittle failure especially in the event of an earthquake. In this paper, the forces in lateral ties in a typical brick veneer wall system are evaluated when the building is subjected to some earthquake records. Distribution of tie forces resulting from the dynamic analysis of a finite element model of the brick veneer-masonry block wall system are determined and compared to the conventional assumption. The performance of a corrosion resistant stainless steel helical tie is compared with that of conventional masonry ties. The potential advantages of this relatively new type of masonry tie are discussed with respect to its use in seismic regions.     

内插保温层空心砌块的热工性能及其改进措施

根据国家对建筑能耗节能50%和节材的要求,目前在夏热冬冷地区对建筑围护结构普遍采用空心砌块以满足对热阻的要求。应用热流计法对内插保温层空心砌块的热阻进行了实验研究,分析了砌块的热工性能,找出该空心砌块存在的不足,并分别着眼于砌块外部结构和内部构造提出了改进方法,使砌体能够满足夏热冬冷地区对建筑围护结构节能的要求。     

The impact of thermal bridges on the energy demand of buildings with double brick wall constructions

The implementation of the European Directive on the Energy Performance of Buildings (EPBD) is a milestone towards the improvement of energy efficiency in the building sector. However, even in cases where impressive measures can be implemented in the densely built urban environment, the less glamorous measure of building's envelope thermal insulation remains a prerequisite towards the improvement of the building's energy efficiency. Despite the insulation requirements specified by national regulations, thermal bridges in the building's envelope remain a weak spot in the constructions. Moreover, in many countries construction practices tend to implement only partially the insulation measures foreseen by regulations. As a result, thermal losses are in practice greater than those predicted during the design stage. This paper presents a study on representative wall thermal insulation configurations used in Greek buildings, in order to investigate the impact of the thermal bridges on the energy consumption. The double wall construction, used widely in Greece and not only there, is rather susceptible to the occurrence of thermal bridges, in contrast to a typical thermal insulating façade, like the one applied in Central Europe. The analysis of the thermal bridges’ impact will in that sense also highlight the potential for energy renovation measures in older buildings.     

全再生废砖骨料混凝土导热系数试验分析与预测

以3种不同的再生废砖粗骨料替代率(40%、70%、100%)和再生废砖细骨料替代率(40%、70%、100%)设计7组试验,对再生废砖骨料混凝土导热系数进行试验和分析。试验结果表明:提高再生废砖粗骨料替代率可降低再生废砖骨料混凝土导热系数;在再生废砖粗骨料替代率为100%的基础上,增加再生废砖细骨料的替代率,则再生混凝土导热系数持续下降,其中全再生废砖骨料混凝土导热系数最低,相比普通混凝土降低幅度为57.52%;定义了再生废砖骨料影响系数G,G值越大,再生混凝土导热系数越低;研究了再生砖骨料混凝土导热系数的变化机理,在Hasselman-Johnson模型基础上,提出了再生废砖骨料混凝土导热系数修正公式,计算预测值与试验值吻合良好。     

地震区底层带商店建筑合理结构形式的研究

在地震区,底层带商店建筑可采用的结构形式有底部框架剪力墙上部砌体结构、多层内框架结构、多层全框架结构、多层砌体结构等;不应采取底层内框架砖房、底层纯框架砖房等形式。正确选择底层带商店建筑的结构形式,有利于降低工程造价,确保结构安全。     

Thermal behaviour of adobe constructions

Adobe is a construction technique that uses soil (a mixture of clay, sand and water), stabiliser and binder as raw materials that are mixed and moulded to form sun-dried blocks. The objective of this study was to assess how various factors affected the dynamic response of the thermal performance of adobe constructions. On the basis of a bibliographical survey the main factors that affect the thermal behaviour of adobe constructions were ascertained.

Dynamic thermal simulation software, thermal analysis system (TAS), was employed to simulate the performance of adobe constructions using synthetic weather data to reproduce the climatic conditions for three regions from different latitudes in Mexico. An orthogonal array Taguchi was used to define the range of models required to test the various relevant performance parameters and to relate these through observed behaviour patterns. With this tool it was possible to develop an understanding of the complex interactions between variables. In particular, dynamic thermal simulation allowed an understanding of the time lag in delivering/storing energy to and from the indoor environment within the adobe constructions and how this affected the diurnal variations of internal temperatures.     

Improving environmental sustainability of concrete products: Investigation on MWC thermal and mechanical properties

This research focuses on the possibility of constituting a more sustainable lightweight concrete, Mineralized Wood Concrete (MWC), substituting natural aggregates with wastes from woodworking activities. Exploiting this type of aggregates, a triple purpose has been achieved: preservation of natural raw materials, reuse of wastes and energy saving. Furthermore, the use of wood aggregates is a way to try to develop a sustainable concrete characterized by high thermal inertia, high thermal resistance and low weight.In this paper, effects of the addition of wood aggregates on mechanical and thermal properties of concrete are studied. Mechanical performances have been investigated with compressive strength tests, while a one-dimensional heat flow model has been used to predict the thermal conductivity of MWC.The use of MWC can be associated with the idea of a different typology of relatively heavy building envelope: this union could competitively answer to the demand of well-insulated building envelope and concurrently characterized by high thermal mass. From this union, a series of other values can be derived: low weight, environmentally friendly, easily industrialized and easy on-site casting. Consequently, applications of wood concrete in building constructions may be an interesting solution in order to improve sustainability and building energy efficiency.     

外墙外保温外饰面砖在小高层建筑中的应用

结合工程概况,对外墙外保温外饰面施工技术进行了分析,介绍了面砖的基本构造,并对其施工流程及关键材料的质量控制进行了阐述,指出施工中应注意的问题,实践证明,外墙外保温外饰面砖既保温又节能,应用效果良好。