Aerogel insulation for building applications: A state-of-the-art review

Aerogels are regarded as one of the most promising high performance thermal insulation materials for building applications today. With a thermal conductivity down to 13 mW/(m K) for commercial products they show remarkable characteristics compared to traditional thermal insulation materials. Also the possibility of high transmittances in the solar spectrum is of high interest for the construction sector. With the proper knowledge they give both the architect and engineer the opportunity of re-inventing architectural solutions. Within this work, a review is given on the knowledge of aerogel insulation in general and for building applications in particular.     

Phase change materials for building applications: A state-of-the-art review

Phase change materials (PCMs) are regarded as a possible solution for reducing the energy consumption of buildings. By storing and releasing heat within a certain temperature range, it raises the building inertia and stabilizes indoor climate. Within this work, a state-of-the-art review is given on the knowledge of PCMs today for building applications.     

Vacuum insulation panels for building applications: A review and beyond

Vacuum insulation panels (VIPs) are regarded as one of the most promising high performance thermal insulation solutions on the market today. Thermal performances three to six times better than still-air are achieved by applying a vacuum to an encapsulated micro-porous material, resulting in a great potential for combining the reduction of energy consumption in buildings with slim constructions. However, thermal bridging due to the panel envelope and degradation of thermal performance through time occurs with current technology. Furthermore, VIPs cannot be cut on site and the panels are fragile towards damaging. These effects have to be taken into account for building applications as they may diminish the overall usability and thermal performance.This paper is as far as the authors know the first comprehensive review on VIPs. Properties, requirements and possibilities of foil encapsulated VIPs for building applications are studied based on available literature, emphasizing thermal bridging and degradation through time. An extension is made towards gas-filled panels and aerogels, showing that other high performance thermal insulation solutions do exist. Combining the technology of these solutions and others may lead to a new leap forward. Feasible paths beyond VIPs are investigated and possibilities such as vacuum insulation materials (VIMs) and nano insulation materials (NIMs) are proposed.     

Traditional, state-of-the-art and future thermal building insulation materials and solutions - Properties, requirements and possibilities

The advantages and disadvantages of the thermal building insulation materials and solutions have been treated. Both traditional, state-of-the-art and possible materials and solutions beyond these have been investigated. Examples of these may be mineral wool, expanded polystyrene, extruded polystyrene, polyurethane, vacuum insulation panels, gas insulation panels, aerogels, and future possibilities like vacuum insulation materials, nano insulation materials and dynamic insulation materials. Various properties, requirements and possibilities have been compared and studied. Among these are thermal conductivity, perforation vulnerability, building site adaptability and cuttability, mechanical strength, fire protection, fume emission during fire, robustness, climate ageing durability, resistance towards freezing/thawing cycles, water resistance, costs and environmental impact. Currently, there exist no single insulation material or solution capable of fulfilling all the requirements with respect to the most crucial properties. That is, for the buildings of today and the near future, several insulation materials and solutions are used and will have to be used depending on the exact circumstances and specifications. As of today, new materials and solutions like e.g. vacuum insulation panels are emerging, but only slowly introduced in the building sector partly due to their short track record. Therefore it will be of major importance to know the limitations and possibilities of all the insulation materials and solutions, i.e. their advantages and disadvantages. In this respect new conceptual thermal building insulation materials are also discussed.     

幕墙工程保温材料的选择和应用

本文通过对不同幕墙保温材料的特点和性能进行对比,对新型酚醛泡沫保温板材的性能进行了全面分析,介绍了广州国际体育演艺中心保温系统的材料选择和应用过程     

Encapsulated vacuum insulation panels: theoretical thermal optimization

A vacuum insulation panel (VIP) is a new thermal insulation material consisting of an open-celled core material which is evacuated and then sealed with a thin barrier laminate. When it is integrated into an expanded polystyrene (EPS) insulation board and entirely encapsulated by a protective material, an additional thermal bridge occurs along the component's perimeter. A theoretical parameter study examines the effects of integrating a VIP into an insulation board with a fixed thickness of 100 mm. Several parameters were varied: thermal conductivity and the thickness of the VIP core, the thickness of the envelope, the thickness of the EPS layers and the width of the EPS strips along the component's perimeter. Both two- and three-dimensional numerical studies reveal a certain VIP maximum thickness for optimal thermal performance. For the three-dimensional component, this thickness is near 30 mm or 95 mm for, respectively, a 40 µm- or a 6 µm-thick aluminium foil-based barrier laminate. For these components, the overall thermal resistance was found to be, respectively, 35% or 137% higher than a 100 mm-thick EPS insulation board. However, no maximum thermal performance was found for an encapsulated VIP containing a three-layer metallized barrier laminate.

Le panneau isolant sous vide (PIV) est un nouveau matériau d'isolation thermique comportant une âme constituée d'un matériau à pores ouverts, qui est mise sous vide et hermétiquement scellée au moyen d'une mince barrière en stratifié. Lorsque le PIV est intégré à un panneau isolant en polystyrène expansé (EPS) et entièrement encapsulé par un matériau protecteur, un pont thermique supplémentaire se produit le long du périmètre de cet élément. Une étude théorique des paramètres examine les effets de l'incorporation d'un PIV dans un panneau isolant d'une épaisseur fixe de 100 mm. Plusieurs paramètres sont modifiés: la conductivité thermique et l'épaisseur de l'âme du PIV, l'épaisseur de l'enveloppe, l'épaisseur des couches de polystyrène expansé (EPS) et la largeur des bandes de polystyrène expansé le long du périmètre de l'élément. Les études numériques aussi bien bidimensionnelles que tridimensionelles révèlent qu'une certaine épaisseur maximale des PIV permet d'obtenir un rendement thermique global. S'agissant de l'élément tridimensionnel, cette épaisseur est proche de 30 mm ou de 95 mm, respectivement, pour un stratifié basé sur une feuille d'aluminium de 40 µm ou 6 µm d'épaisseur. Concernant ces éléments, il a été constaté que la résistance thermique globale était, respectivement, de 35% ou 137% supérieure à celle d'un panneau isolant en polystyrène expansé de 100 mm. Néanmoins, il n'a été constaté aucun rendement thermique maximum pour un PIV encapsulé contenant un stratifié métallisé triple couche.

Mots clés: panneaux isolants sous vide (VIP) encapsulés, isolation, optimisation, rendement thermique, panneaux isolants sous vide     

保温粉刷材料及其应用技术

一种新型的粉刷类保温材料已在上海多项工程中使用。它具有导热系数小、保温性能好、施工方便、可操作姓好以及粉刷层质量优３大特点，且经济上也可行，受到建筑科研、设计、施工、房产开发及有关方面的青睐。介绍了该材料的性能、特点与应用技术，并作经济分析。     

预制混凝土夹心保温墙板热工性能优化设计建议

预制混凝土夹心保温墙板具有较好的承载、保温与隔声等性能,是目前装配式建筑中主流的外围护构件,但在目前的设计与实际应用中,墙板实际的热工性能未能充分的得到发挥。结合前期学者的理论研究与实际的工程应用,针对如何提升墙板热工性能给出了优化设计的建议,为夹心保温墙板的设计与应用提供参考。     

建筑物系统节能保温材料性能比较

阐述了保温节能材料的重要性,从墙体材料到墙体保温材料再到门窗材料几方面进行了分析,通过性能对比,表述了新型保温节能材料的优越性,同时满足消防要求,值得推广应用。     

Simplified thermal and hygric building models: A literature review

This paper provides a systematic literature review on simplified building models. Questions are answered like: What kind of modelling approaches are applied? What are their (dis)advantages? What are important modelling aspects? The review showed that simplified building models can be classified into neural network models (black box), linear parametric models (black box or grey box) and lumped capacitance models (white box). Research has mainly dealt with network topology, but more research is needed on the influence of input parameters. The review showed that particularly the modelling of the influence of sun irradiation and thermal capacitance is not performed consistently amongst researchers. Furthermore, a model with physical meaning, dealing with both temperature and relative humidity, is still lacking. Inverse modelling has been widely applied to determine models parameters. Different optimization algorithms have been used, but mainly the conventional Gaus–Newton and the newer genetic algorithms. However, the combination of algorithms to combine their strengths has not been researched. Despite all the attention for state of the art building performance simulation tools, simplified building models should not be forgotten since they have many useful applications. Further research is needed to develop a simplified hygric and thermal building model with physical meaning.     

一种测试建筑隔热涂料导热系数的方法

减少建筑能耗是工程领域的一个重要课题,评价节能效果的方法尤为重要。对于建筑隔热涂料,导热系数是评价其隔热性能的重要指标,其准确测试对于建筑隔热涂料评价、节能效果预测、新涂料研制开发等有重要意义。本文通过理论推导得到一种简便的涂料导热系数评价方法,并选取样品进行了验证。     

浅析引气橡胶混凝土砌块

以引气橡胶混凝土砌块为研究对象,在实验室实测了材料的强度、导热系数和蓄热系数,分析了砌块的热工性能和评价指标,提出了其发展前景。引气橡胶混凝土作为新型保温隔热墙体材料,热工性能良好,可广泛用于多层建筑承重和非承重内外墙体,也可用于屋面保温。     

Performance analysis of the building envelope: A case study of the Main Hall,Shinawatra University

The envelope of the Main Hall, Shinawatra University has been designed to provide protection from energy gain. According to initial estimates, the Main Hall could achieve an overall thermal transfer value (OTTV) of 10.16 W/m², which is four times lower than those recommended by the Thai national standard. This study aims to evaluate the actual energy performance of the Main Hall building envelope using field measurements and simulations. The air temperature, surface temperature, and relative humidity were measured at frequent intervals, both indoors and outdoors. Hourly average meteorological data for insolations were utilized in order to calculate the solar gain by light transmission. Based on the empirical data, the energy fluxes through the envelope on eight different orientations were simulated and the average value was found within 7% of the estimated OTTV. Using the same empirical data for the outdoor condition, simulations of other common types of building envelope in Thailand were carried out for comparison. The results of the analysis show that the Main Hall's lightweight and highly insulated building envelope outperforms other commonly used heavyweight envelopes in preventing building energy gain in the hot-humid climate of Thailand. Although the use of the lightweight and highly insulated envelope helps reduce the operating and investment costs of the air conditioning system as well as the cost of building structure, it also increases the investment cost of the envelope substantially. However, the life cycle cost analysis (LCCA) reveals that the life cycle cost (LCC) of the Main Hall envelope is the most economical, and the increased investment cost of the Main Hall envelope requires a discounted payback period of only 3–5 years, depending on the envelope types used in the comparison. Furthermore, it should be noted that greater savings and a more favorable pay back period could be obtained if this highly energy efficient envelope is applied to other typical buildings, especially high-rise structures in urban areas.     

A frost decay exposure index for porous,mineral building materials

The disintegrative process of freezing and thawing of porous, mineral materials represents a significant challenge in the design and construction of building enclosures. In this paper, we present a simple method for assessing the relative potential of a climate to accelerate frost decay based on multi-year records of daily air temperatures and rainfall, with special emphasis on masonry. Distributions of 4-day rainfall prior to days with freezing events provide quantitative information on the geographically dependant frost decay risk in porous, mineral building materials in a given climate. Data from 168 weather stations in Norway are analysed, using weather data from the reference 30-year period 1961–1990.     

Numerical modeling for rockbursts: A state-of-the-art review

As the depth of excavation increases,rockburst becomes one of the most serious geological hazards damaging equipment and facilities and even causing fatalities in mining and civil engineering.This has forced researchers worldwide to identify different methods to investigate rockburst-related problems.However,some problems,such as the mechanisms and the prediction of rockbursts,continue to be studied because rockburst is a very complicated phenomenon influenced by the uncertainty and complexity in geological conditions,in situ stresses,induced stresses,etc.Numerical modeling is a widely used method for investigating rockbursts.To date,great achievements have been made owing to the rapid development of information technology(IT)and computer equipment.Hence,it is necessary and meaningful to conduct a review of the current state of the studies for rockburst numerical modeling.In this paper,the categories and the origin of different numerical approaches employed in modeling rockbursts are reviewed and the current usage of various numerical modeling approaches is investigated by a literature research.Later,a state-of-the-art review is implemented to investigate the application of numerical modeling in the mechanism study,and prediction and prevention of rockbursts.The main achievements and problems are highlighted.Finally,this paper discusses the limitations and the future research of numerical modeling for rockbursts.An approach is proposed to provide researchers with a systematic and reasonable numerical modeling framework.     

对民用建筑工程保温材料燃烧性能的要求的几点意见

公安部消防局《关于进一步明确民用建筑外保湿材料消防监督管理有关要求的通知》要求民用建筑外保温材料采用燃烧性能为A级的材料。这一通知给建筑外保温相关行业带来连锁反应。该文即针对外保温材料燃烧性能等级是否应强制为A级加以分析。     

Combined heat transfer of radiation and conduction in stacked radiation shields for vacuum insulation panels

Combined heat transfer of radiation and conduction considering depthwise conduction phenomena in stacked radiation shields for vacuum insulation panels (VIPs) having an artificial core structure is investigated. The purpose of this study is to establish a reliable analysis method for actual shield design. A one-dimensional problem is first analyzed. Actual two-dimensional problem is simplified for theoretical modeling and the depthwise conduction around contact spot is further considered. Test radiation shields are manufactured using press molding process with SUS 304 (AISI grade 304) plates, since this sample depicts the parametric effects well. Measurement of the effective thermal conductivity is performed with a VGHP apparatus. While various analytical and numerical models predict the effective thermal conductivity in the case of this specific specimen within about 40% error, the combined heat transfer analysis considering depthewise conduction phenomena is accurate within 10% error and it is thus recommended in estimating the effective thermal conductivity of stacked radiation shields.     

A methodology for assessing the energy performance of large scale building stocks and possible applications

From energy statistics (primary energy consumption) and a few Census data (residential buildings floor area) the average specific primary energy use (kWh/m²) of a territorial (Regional or National) building stock may be easily evaluated. However, can we achieve a deeper insight on this building stock using basically the same data bases? This is the question which this paper is aiming at, and the results is an analytical methodology to determine the Statistical Distribution Of residential Buildings according to primary Energy consumption for heating purposes (E-SDOB) at a Regional or National scale. This tool may allow the legislator to define a performance scale for building energy certification, to introduce mandatory measures and incentives for building energy retrofits, to evaluate the potential of new technologies, etc. The main source of data required for determining E-SDOB is still the National Census, but it has to be integrated by energy standards and laws, literature and a few data taken from the authors’ experience and in situ analysis. The results obtained have been compared with those derived from two Italian Regional (Piedmont and Lombardy) energy statistics, with excellent agreement.     

A nodal thermal model for photovoltaic systems: Impact on building temperature fields and elements of validation for tropical and humid climatic conditions

This article deals with both an experimental study and a numerical model of the thermal behaviour of a building whose roof is equipped with photovoltaic panels (PV panels). The aim of this study is to show the impact of the PV panels in terms of level of insulation or solar protection for the building. Contrary to existing models, the one presented here will allow us to determine both the temperature field of the building and the electric production of the PV array. Moreover, an experimental study has been conducted in La Reunion Island, where the climate is tropical and humid, with a strong solar radiation. In such conditions, it is important to minimise the thermal load through the roof of the building. The thermal model is integrated in a building simulation code and is able to predict the thermal impact of PV panels installed on buildings in several configurations and also their production of electricity. Basically, the PV panel is considered as a complex wall within which coupled heat transfer occurs. Conduction, convection and radiation heat transfer equations are solved simultaneously to simulate the global thermal behaviour of the building envelope including the PV panels; this is an approach we call ‘integrated modelling’ of PV panels. The experimental study is used to give elements of validation for the numerical model and a sensitivity analysis has been run to put in evidence the governing parameters. It has been shown that the radiative properties of the PV panel have a great impact on the temperature field of the tested building and the determination of these parameters has to be taken with care.