Nuno M.M. Ramos

Application of Data Mining Techniques

In this chapter, the data mining techniques described in chapter 3 are applied to the case study described in chapter 4. The overcome of the difficulties associated with the analysis process of the data using appropriate techniques is demonstrated.

Hygrothermal numerical simulation: application in moisture damage prevention

1.1 Background Building pathologies originated by moisture are frequently responsible for the degradation of building components and can affect users’ health and comfort. The solutions for treating moisture related pathologies are complex and, many times, of difficult implementation. Several of these pathologies are due to innovative techniques combined with new materials of poorly predicted performance. The knowledge of the physical processes that define hygrothermal behaviour allows for the prediction of a building response to climatic solicitation and for the selection of envelope solutions that will lead to required feasibility. Over the last five decades, hundreds of building energy software tools have been developed or enhanced to be used. A list of such tools can be obtained in the US Department of Energy Webpage (2007). This directory provides information for more than 345 building software tools for evaluating energy efficiency, renewable energy and sustainability in buildings. The problem of moisture damage in buildings has attracted interest from the early days of the last century, but it was during the past decades that the general topic of moisture transport in buildings became the subject of more systematic study, namely with the development of the modelling hygrothermal performance. In the field of building physics the hygrothermal models are widely used to simulate the coupled transport processes of heat and moisture for one or multidimensional cases. The models may take into account a single component of the building envelope in detail or a multizonal building. In literature, there are many computer-based tools for the prediction of the hygrothermal performance of buildings. These models vary significantly concerning their mathematical sophistication and, as shown Straube and Burnett (1991), this sophistication depends on the degree to which the model takes into consideration the following parameters: moisture transfer dimension; type of flow (steady-state, quasi-static or dynamic); quality and availability of information and stochastic nature of various data (material properties, weather, construction quality, etc.). All the hygrothermal simulation tools presented later in this paper are based on one of the following numerical methods for space and time discretization: a. Finite Difference Methods (FDM) and Finite Control Volume (FCV) methods; b. Finite Element Method (FEM); c. Response Factor and Transfer Function method.

Energy and Water Consumption Variability in School Buildings: Review and Application of Clustering Techniques

AbstractIn developed countries, the building sector is responsible for a very significant share of the total energy consumption. School buildings, because they are places where children are educated and learn to become active members of the society, should be a good example of an efficient use of energy and water. In this study, data of the energy and water consumption of 23 Portuguese schools and their main building characteristics and properties were gathered. This information was normalized to homogenize the data set and then analyzed using advanced clustering techniques. The results show a significant variability in the consumption of different schools, even with similar characteristics, suggesting that the user behavior plays an important role in their efficiency. The complete linkage and Ward’s clustering methods were applied, both produced three clusters, and reference values for electricity and water consumption were defined.

The Evaluation of Hygroscopic Inertia and Its Importance to the Hygrothermal Performance of Buildings

Heating and ventilating are fundamental actions for the control of humidity in the indoor environment, but the hygroscopic inertia provided by the materials that contact the inside air can be a complement for that control. The hygroscopic behavior of the walls and ceiling finishing materials, as well as furniture and textiles inside the dwellings, defines their hygroscopic inertia. Reducing the persistence of high relative humidity values inside buildings is essential for the control of mould growth on material surfaces, that can otherwise cause degradation and bring about social and economical problems for the users. As the hygroscopic inertia concept can be very difficult to approach for building designers, a definition of daily hygroscopic inertia classes is presented, based on numerical and laboratory work on this subject. An outline of a simple method, using those classes, that allows for the evaluation of the reduction of mould growth potential associated to a configuration of inside finishes is proposed. The extensive experimental campaign aiming the characterization of the moisture buffering capacity of interior finishing system and the assessment of a room’s hygroscopic inertia is described. The MBV—Moisture Buffer Value is evaluated for different revetments. The assessment of hygroscopic inertia at room level is implemented using a flux chamber designed specifically for this experiment. A daily hygroscopic inertia index, I h,d , is defined using MBV as a basis for the assessment of materials contribution to the buffering capacity of a room. The correlation between that index and peak dampening is proved using the presented experimental results. Systematic simulation of the set of dynamic experiments of transient moisture transfer in the hygroscopic region is presented; allowing to verifying and correcting the modeling assumptions and the basic data used in simulations, and conclude on the most effective strategies to conduct this type of simulations.

Health and living conditions in social housing: comparison between rehabilitated and non-rehabilitated neighbourhoods

AimOur aim is to compare how residents from two social housing neighbourhoods of Porto City, one rehabilitated and one non-rehabilitated, perceived their living conditions, health and quality of life.Subjects and methodsA cross-sectional study was conducted, selecting residents from two social housing neighbourhoods of Porto City, one rehabilitated and another one non-rehabilitated. The information was collected through quantitative (a structured questionnaire; n = 82) and qualitative face-to-face interviews administered by trained interviewers (n = 16).ResultsNo significant differences were found between populations from both neighbourhoods regarding social, behavioural and health characteristics. The major differences among neighbourhoods were found on variables such as satisfaction with house, the need of rehabilitation work, and the absence of mould and dampness in the house (p < 0.001) as well as pollution (p < 0.05). Qualitative data showed that residents from the rehabilitated houses were pleased not to have been moved to another location and were very satisfied with the rehabilitation work, which in their perception contributed to the residents’ wellbeing. Nominal and ordinal variables were described using proportions and compared using the chi-square test. Quantitative continuous variables were presented as a median (percentile 25 to percentile 75) and they were compared via the Mann-Whitney test.ConclusionPublic economic and financing resources should be redirected to social housing rehabilitation that, although in the short term does not have a direct impact on health savings for the occupants, is an important dimension of the residents’ sense of wellbeing and satisfaction.

Influence of indoor hygrothermal conditions on human quality of life in social housing

Background: Modern societies spend most of their time indoors, namely at home, and the indoor environment quality turns out to be a crucial factor to health, quality of life and well-being of the residents. The present study aims to understand how indoor environment relates with quality of life and how improving housing conditions impacts on individuals’ health. Design and Methods: This study case will rely on the following assessments in both rehabilitated and non-rehabilitated social housing: i) field measurements, in social dwellings (namely temperature, relative humidity, carbon dioxide concentration, air velocity, air change rate, level of mould spores and energy consumption); ii) residents’ questionnaires on social, demogaphic, behavioural, health characteristics and quality of life. Also, iii) qualitative interviews performed with social housing residents from the rehabilitated houses, addressing the self-perception of living conditions and their influence in health status and quality of life. All the collected information will be combined and analysed in order to achieve the main objective. Expected impact It is expected to define a Predicted Human Life Quality (PHLQ) index, that combines physical parameters describing the indoor environment measured through engineering techniques with residents’ and neighbourhood quality of life characteristics assessed by health questionnaires. Improvement in social housing should be related with better health indicators and the new index might be an important tool contributing to enhance quality of life of the residents. Significance for public health This study will contribute to understand how indoor environment relates with quality of life and how improving housing conditions impacts on individuals’ health, in social housing neighbourhoods. As so, it is important to share the undertaken methodology carried out by a multidisciplinary team, in order to allow other researchers following comparable studies to adopt a similar approach. The case study results will allow to define building rehabilitation policies, improving residents’ quality of life and adding great contribution to public health promotion.

Probabilistic Risk Assessment Methodology of Exterior Surfaces Defacement Caused by Algae Growth

AbstractThis paper presents the development of a risk assessment methodology applicable to the analysis of exterior surfaces defacement from algae growth. The specific case of external thermal insulation composite systems (ETICS) is frequently associated with a higher perceived risk if compared with other facade solutions. The design of the proposed methodology includes: the scope of the risk analysis definition, the determination of the parameters involved using a qualitative analysis of the problem, the collection of relevant data, and a quantitative probabilistic risk analysis based in Monte Carlo simulations. The detailed implementation of the methodology involved the preparation of a meta-model, response surface methodology, that was developed and compared with a hygrothermal simulation tool. The meta-model allowed a faster application of the Monte Carlo method, providing results of the methodology application to the use of ETICS in selected locations and a sensitivity analysis of the stochastic para...

Hygrothermal Simulation Tools

Different models for the coupled heat, air, moisture and salt transport have been developed and incorporated into various software programs used in the field of porous building materials and in the closely related field of wetting and drying of soils.

Data Mining Techniques

This chapter presents available data mining techniques that can be of interest for application in indoor environment analysis. Descriptive statistics tools are presented with the focus on probability distribution and correlation analysis. Multivariate data techniques are also addressed, with a special focus on principal components determination and cluster analysis.

Indoor Hygrothermal Conditions

The evaluation of indoor hygrothermal conditions is described, supported by a literature review. Involved parameters and standardized methodologies are summarized. The procedures for evaluation of human comfort are also briefly described.