围护结构霉菌种类识别及生长风险研究

围护结构霉菌生长不仅会影响围护结构的热工性能,还会危害室内空气质量和人员健康.以上海市某居民小区为研究对象,通过现场采集和DNA高通量测序,对围护结构中的霉菌种类进行了识别.基于菌种识别结果,选择文献中相应菌属的培养数据,建立了用于霉菌生长风险预测的等值线模型.基于最佳温度下霉菌生长速率和相对湿度的函数关系式对该模型进...     

复杂通风方案设计计算方法研究

方案阶段的自然通风设计主要关注的是通风路径,而一般来说此阶段的部分开口信息未知.本文针对建筑设计的特点,提出了面向方案阶段复杂通风方案的设计计算方法,针对部分开口信息未知的情况,基于稳态热平衡模型和多区域通风网络模型建立了最优化计算模型,并以“未知开口平均面积的最小值”作为通风方案评估指标.将该设计计算方法用于比较单中庭和双中庭通风方案,发现单中庭方案部分楼层出现了气流“倒灌”现象,而双中庭方案可节省37.1％的开口面积.     

A technique for the prediction of the conditions leading to mould growth in buildings

Epidemiological evidence suggests that the presence of mould growth in buildings can have a detrimental effect on the well-being of occupants. Based on an extensive literature review, growth limits for six generic mould categories have been formulated in terms of the minimum combination of temperature and relative humidity for which growth will occur on building materials. These limits were incorporated within the ESP-r system for building energy and environmental simulation in order to provide a design tool which can predict the likelihood and extent of mould infestation. The systems new predictive capability has been tested against monitored data and mycological samples taken from a mould infested house.     

Coupling of thermal mass and natural ventilation in buildings

The coupling of thermal mass and natural ventilation is important to passive building design. Thermal mass can be classified as external thermal mass and internal thermal mass. Due to great diurnal variation of ambient air temperature and solar radiation intensity, heat transfer through building envelopes, which is called external thermal mass, is a complex and unsteady process. Indoor furniture are internal thermal mass, affecting the indoor air temperature through the process of absorbing and releasing heat. In this paper, a heat balance model coupling the external and internal thermal mass, natural ventilation rate and indoor air temperature for naturally ventilated building is developed. In this model, the inner surface temperature of building envelopes is obtained based on the harmonic response method. The effect of external and internal thermal mass on indoor air temperature for six external walls is discussed of different configurations including lightweight and heavy structures with and without external/internal insulation. Based on this model, a simple tool is developed to estimate the indoor air temperature for certain external and internal thermal mass and to determine the internal thermal mass needed to maintain required indoor air temperature for certain external wall for naturally ventilated building.     

Der neue DIN‐Fachbericht 4108‐8 Vermeidung von Schimmelwachstum in Wohngebäuden

Zunehmend wird wieder von Problemen des Schimmelpilzwachstums in Wohngebäuden berichtet. Die Baukonstruktion eines Wohngebäudes muss die Voraussetzung schaffen, dass bei üblicher, bestimmungsgemäßer Nutzung der Räume die Innenoberflächen der Bauteile so warm und trocken bleiben, dass Schimmelpilzwachstum vermieden wird. Gegebenenfalls sind entsprechende Wärmedämm‐ und anlagentechnische Sanierungsmaßnahmen erforderlich. Gleichzeitig muß das Nutzerverhalten den baukonstruktiven und nutzungsbedingten Gegebenheiten angepasst sein. Dazu gehört eine gleichmäßige Beheizung, eine ausreichende Belüftung, eine weitgehend ungehinderte Luftzirkulation durch entsprechende Möblierung, sowie eine nicht ungemessen hohe Feuchtefreisetzung. Der DIN‐Fachbericht 4108‐8 “Wärmeschutz und Energieeinsparung in Gebäuden — Teil 8: Vermeidung von Schimmelwachstum in Wohngebäuden” fasst die Einflussfaktoren Baukonstruktion, Heizung, Lüftung, Nutzung/Nutzerverhalten zu einer ganzheitlichen Betrachtung zusammen. Er hilft bei der Klärung von Ursachen und bei der Einleitung von Gegenmaßnahmen. Avoiding mould growth in dwellings — the new report on DIN 4108‐8. Problems with mould growth in residential buildings are an increasing occurrence. The construction of a dwelling house should ensure that, provided rooms are used in accordance with the design purpose, the internal surfaces of the building components stay sufficiently warm and dry so that mould growth is avoid ed. Where this is not the case, remedial measures have to be undertaken, such as installing additional insulation and/or ventilation/ heating devices. But it is equally important that the behaviour of the users of a building is appropriate for the design of the building. This includes evenly distributed space heating, adequate ventilation, air circulation that is largely unobstructed by furniture, and that moisture release in the dwelling is not excessive. The report on DIN 4108‐8 ‘Thermal insulation and conserving energy in buildings — Part 8: Avoiding mould growth in dwellings’ takes a comprehensive look at all relevant factors, such as construction details, heating and ventilation systems, and user behaviour. The report helps to clarify the causes of problems and makes suggestions for remedial actions.     

Computational analysis of wind driven natural ventilation in buildings

The design of natural ventilation in buildings is often performed by means of computational fluid dynamics (CFD) techniques, whose application is gaining popularity. In the present study, Reynolds averaged Navier–Stokes equation (RANS) approach is applied to wind driven natural ventilation in a cubic building. Two different models are considered, namely the two-equation k–ɛ model and the Renormalization Group (RNG) theory. The velocity and pressure distribution inside and around the building are determined, as well as the ventilation rate, for three different configurations: cross ventilation, single-sided ventilation with an opening on the windward wall and single-sided ventilation with an opening on the leeward wall. The numerical results are compared with experimental data, showing a good agreement, particularly when using RNG. The discrepancy in the determination of the ventilation rate is reasonable and the flow distribution inside the building is properly described when RNG model is used. However, the k–ɛ model fails to determine the correct velocity components near the horizontal surfaces. According to these results, the RNG model can be considered a useful tool for the study of wind driven natural ventilation, especially for the assessment of the ventilation rate and of the air distribution inside a room.     

Using building simulation to model the drying of flooded building archetypes

With a changing climate, London is expected to experience more frequent periods of intense rainfall and tidal surges, leading to an increase in the risk of flooding. This paper describes the simulation of the drying of flooded building archetypes representative of the London building stock using the EnergyPlus-based hygrothermal tool ‘University College London-Heat and Moisture Transfer (UCL-HAMT)’ in order to determine the relative drying rates of different built forms and envelope designs. Three different internal drying scenarios, representative of conditions where no professional remediation equipment is used, are simulated. A mould model is used to predict the duration of mould growth risk following a flood on the internal surfaces of the different building types. Heating properties while keeping windows open dried dwellings fastest, while purpose built flats and buildings with insulated cavity walls were found to dry slowest.     

Wind-induced natural ventilation of re-entrant bays in a high-rise building

This paper reports a systematic computational study of wind-induced natural ventilation and pollutant transport of re-entrant bays on a total of 30 generic building models of different building heights and with bays of different dimensions. Mean wind flow around each building model and wind-induced flow inside re-entrant bays are computed. To determine the ventilation efficiency of the bay, the computed flow field is used to disperse a scalar pollutant initially occupying the entire bay at a uniform concentration. The subsequent time decay of pollutant concentration inside the bay is studied and the ventilation efficiency is quantified by the retention time. The results show that wind-induced flow inside the bay, especially on the building side face, is complex and highly three-dimensional. Air exchange rates through the roof opening and vertical side opening are analyzed for each bay and their relationship to the ventilation efficiency is discussed. The bays on the building side faces are much worse ventilated than those on the windward or leeward building face. The deeper the side bay, the worse is the air exchange and ventilation. The building height is found to have a governing effect on the ventilation of the windward and leeward re-entrant bays.     

Critical conditions for onset of mould growth under varying climate conditions

A performance-based service life design format based on climatic exposure on one hand and “resistance” of materials against mould growth on the other hand, is presented in this paper. A limit state for onset of mould growth is defined as the occurrence of traces of mould observed by microscopy. A dose–response model is proposed by which onset of mould growth can be predicted for an arbitrary climate history of combined relative humidity ? and temperature T. The model is calibrated and verified against a comprehensive set of experimental data published by Viitanen et al. [Viitanen H, Ritschkoff A-C. Mould growth in pine and spruce sapwood in relation to air humidity and temperature. Uppsala: Swedish University of Agricultural Sciences, Department of Forest Products; 1991. Report No. 221, 49 p.; Viitanen H. Modelling the time factor in the development of mould fungi – effect of critical humidity and temperature conditions in pine and spruce sapwood. Holzforschung 1997;51(1):6–14; Viitanen H. Modelling the time factor in the development of brown rot decay in pine and spruce sapwood – the effect of critical humidity and temperature conditions. Holzforschung 1997;51(2):99–106; Viitanen H, Bjurman J. Mould growth on wood under fluctuating humidity conditions. Material und Organismen 1995;29(1):27–46] describing mould development on spruce and pine sapwood as a function of climatic exposure. The model is applied to predict time to onset of mould growth under natural outdoor climate (under shelter) as well as mould development in building attics and in crawl space foundations. The predicted response shows reasonable agreement with experimental observations and proven experience, although biological processes of this type display great variability. The results show that a generally applicable, quantitative model can be used as a powerful tool for moisture safe design in practice. The model is designed to facilitate continuous improvement of prediction capability by further laboratory testing of various materials under specified climate conditions. In combination with currently available building physics software the model is suitable for moisture safe design of wood-based components in the building envelope.     

Experimental evaluation of the growth rate of mould on finishes for indoor housing environments: Effects of the 2002/91/EC directive

We report the results of a study to evaluate the growth rate of three species of mould on plasters, finishes and paints typically used in structures with heavy weight building envelopes. The aim was to determine the influence of the chemical composition (in terms of organic fraction of the materials) on the growth rate of moulds. The study was carried out in the following steps: – characterization of materials; – inoculation of mould spores (3 species) on 7 types of material (2 plasters, 3 finishes, 2 paints); – growth in a climatic chamber (23 °C and 90% RH); – analysis of the mould growth rate using various experimental techniques (fluorescence microscopy analysis, thermogravimetric analysis, etc.). Results show a clear correlation between the organic substances contained in paints, plasters and finishes and the growth rate of the mould.     

某报告厅空调系统的设计及其能耗分析

介绍了西安某办公楼报告厅空调系统的设计。分别应用置换通风与混合通风两种通风方式，在室外和室内设计参数相同的情况下，充分比较了它们在送风量、新风量、能耗以及室内空气品质的不同。结果表明在某些应用场合，置换通风在空气品质提高和能耗降低上有明显的优势，同时这种优势不以牺牲热舒适性为代价，因此建议使用置换通风系统。     

Energy optimal control of a residential space-conditioning system based on sensible heat transfer modeling

Nowadays most HVAC systems for residential building in the Unites States use a single-zone, two-position control system which is simple and easy to manage. However, this two-position control system has its disadvantage for its unsatisfactory thermal comfort and energy efficiency. This paper presents a proportional control system for the residential building by seting up the dynamic simulation for the building and the control system. The state-space method is used to model the building system and the simulation code is implemented on MATLABTM. Under this model, optimization of the controller is possible and implemented. The thermal comfort and energy efficiency are compared under the different schemes. It has been found that proportional control is advantageous to the two-position control for the thermal comfort while there is not much difference in energy consumption between two control schemes. However, in this work the furnace was operated without any minimum run time and under continuous data sampling.     

Internal surface condensation risk in façades of Spanish social dwellings

ABSTRACT

The poor maintenance of social dwellings causes the possible building deficiencies to be significantly increased, especially when most of these dwellings have been built before any thermal standard and without considering the effect of climate change. Façades are one of the building elements which are most degraded by the contact with the exterior, and surface condensation is the most common cause. This study applies the calculation of surface condensation from ISO 13788 to a representative case of social dwelling in Spain for all climate zones, both in the current and 2050 scenarios. Risks of corrosion, mould formation, and surface condensation were studied in nine different points of the façade, which were validated by in-situ measurements. The results determined that there was a greater risk of condensation or mould depending on the climate zone, and thermal resistance significantly influenced data variation in future scenarios. The results also showed that an adequate ventilation generally decreased risks, removing the risk of mould and surface condensation by 2050. To predict the results obtained, a model based on artificial neural networks was generated, and it could also be used to estimate risks in the future.     

典型布局下的建筑室内自然通风

基于三维RNG k-ε湍流模的CFD数值模拟方法,对两种典型室内布局下的套室分别进行室内自然通风模拟研究,获得了一定风速下卧室、客厅等关键部位的风压、风速分布等流场情况;得到典型布局下的通风量。并对自然通风效果进行评价,结果表明建筑室内布局对室内的自然通风效果有一定的影响。隔墙会改变压力、速度的分布,从而影响室内通风;能形成穿堂风的布局是自然通风的理想布局。建筑设计师应设计合理的建筑室内布局,以提高自然通风效果,从而促进建筑节能。     

The impact of zoning regulations on thermal comfort in non-conditioned housing in hot,humid climates: findings from Dhaka,Bangladesh

In parts of the developing world where densities are high but the availability of air conditioning is limited, building massing and height regulations can influence interior comfort levels. Dhaka, Bangladesh, is characterized by high population densities, a lack of open spaces, and high poverty levels, combining to produce living conditions which are not only uncomfortable, but may lead to the spread of disease. A recent change in zoning regulations provides an opportunity to assess the success of building heights and setbacks in improving indoor thermal comfort conditions. We assess the impact on thermal comfort within Dhaka’s non-conditioned apartment buildings of four zoning schemes which differ in their specifications for setbacks, maximum buildable area, and building heights; but that maintains the current density. Computer simulation techniques model the buildings to test solar, daylight, and ventilation inside the central building to calculate resultant indoor temperature, mean radiant temperature, relative humidity and air velocity. Comparison between these values helps to determine which zoning schemes produce the most favorable thermal conditions. Findings suggest that zoning schemes that provide better solar protection and better natural ventilation are able to reduce indoor temperature and increase indoor air velocity over that provided by current zoning regulations. Recommendations for revising current zoning regulations are given along with general recommendations for how buildings in hot, humid climates can maximize passive cooling, encouraging energy savings and environmental sustainability.     

Control strategies for sub-micrometer particles indoors: model study of air filtration and ventilation

The effects of air filtration and ventilation on indoor particles were investigated using a single-zone mathematical model. Particle concentration indoors was predicted for several I/O conditions representing scenarios likely to occur in naturally and mechanically ventilated buildings. The effects were studied for static and dynamic conditions in a hypothetical office building. The input parameters were based on real-world data. For conditions with high particle concentrations outdoors, it is recommended to reduce the amount of outdoor air delivered indoors and the necessary reduction level can be quantified by the model simulation. Consideration should also be given to the thermal comfort and minimum outdoor air required for occupants. For conditions dominated by an indoor source, it is recommended to increase the amount of outdoor air delivered indoors and to reduce the amount of return air. Air filtration and ventilation reduce particle concentrations indoors, with the overall effect depending on efficiency, location and the number of filters applied. The assessment of indoor air quality for specific conditions could be easily calculated by the model using user-defined input parameters.     

Optimal tree design for daylighting in residential buildings

Urban reforestation is advocated as an efficient countermeasure to the intensification of urban heat islands. The greening and beautification of residential quarters is one of the main concerns of residents, while lighting and ventilation are two main energy-consuming building services. Hence, the tree layout in green space between buildings is important, and it is necessary to determine the relationships between trees and buildings. This study takes Shanghai as a case study to optimize tree design between residential buildings and meet good daylighting requirements. Models were made using software such as AutoCAD and SketchUp. The relationships between maximum tree height and building separation were determined. For the same building layout, there were different tree height limits according to crown shape; the order of decreasing height limits was cylindrical, conical, spherical, and inverted conical crowns. Three cases having different green space between building layouts were studied. Their maximum tree heights differed. Overall, our model helps us realize good daylighting of a building environment. The formula allows us to determine which trees to plant between buildings in that we can predict the effects of future tree growth on building daylighting.     

IEA Annex 14: The Zolder Case Study

The Zolder case was one of the six case studies on mould problems and sulface condensation, initiated within the International Energy Agency (IEA) Annex 14 on “Condensation and Energy”. This project, a joint research effort of Belgium, the Federal Republic of Germany, Italy, the Netherlands and the United Kingdom, was completed in March 1990. Complex relations bemeen mould, surface condensation, energy caservation and parameters such as the outdoor climate, the thermal quality of the building, the ventilation and the occupants' behaviour are explained, followed by an analysis of the Zolder-Lindeman case. This illustrates the extent to which mould may deteriorate the livability of a social housing estate. On three houses, different mitigation measures were evaluated before and after implementation: loft space insulation, inside insulation, double glazing outside insulation, natural ventilation, and demand controlled ventilation. The results for one of the three show that the severe mould problems resulted from the cambination of poor overall insulation quality and the impossibility of ventilating properly. A thermal retrofit, together with the installation of a natural ventilation system, proved to be successful.     

高大空间热分层实测与热压通风冷却潜力

以南京某大空间建筑为对象,长45 m、宽15 m、高16 m,在9月过渡季连续多日测试了自然通风状况下的室内温度分布,发现同一垂直方向上温度的线性化程度较好,梯度在0.2℃/m左右,且随室外气象条件变化而变化。采用热压通风效应模型,计算了南京、武汉、重庆、广州4个不同夏热地区全年各月的热压通风量及满足基准通风量要求的最小上部开口面积与通风排热量。利用Energy Plus能耗软件模拟全年各月热压通风热舒适时数,发现广州地区具有最好的热压通风节能潜力。