Hygrothermal Performance of Portuguese Classrooms: Measurement and Computer Simulation

ABSTRACT: The rehabilitation of school buildings is an imperative in Portugal. The current buildings do not guarantee adequate conditions of habitability. So, a very ambitious public plan for rehabilitation of school buildings which involves substantial investments is being carried. It is essential to support this investment plan with a thorough investigation that could help and sustain the technical decisions to be taken. To that end a research project has started with two main objectives: to evaluate the suitability of the legal requirements currently in use in Portuguese codes regarding comfort conditions and ventilation rates through the measurement of temperature, relative humidity and carbon dioxide concentration in classrooms of different schools; and make an optimization of constructive solutions to be used in retrofitting of school buildings using computer simulations, artificial neural networks and genetic algorithms. This paper presents the initial results of this project, from the measured values starts a preliminary discussion and launches the future works of the research project

Metodologia de diagnóstico exigencial de apoio à reabilitação de edifícios de habitação

O nível de degradação do parque habitacional resulta dos investimentos reduzidos em acções de manutenção e conservação dos edifícios e da indefinição e falta de consolidação das políticas públicas que incentivem os proprietários a preservar o património edificado das nossas cidades, que representa um valor económico e cultural incalculável. Quando se decide intervir num edifício e este apresenta um conjunto significativo de patologias não é possível partir directamente para os trabalhos de reabilitação sem um estudo diagnóstico detalhado, em que sejam identificados claramente os problemas, definidas as causas e proposta uma metodologia de intervenção baseada em indicadores de cumprimento das diferentes exigências. O presente trabalho pretende contribuir para a elaboração diagnósticos exigenciais, apresentando-se a estruturação de uma nova metodologia que se denomina Metodologia de Diagnóstico Exigencial Aplicada à Reabilitação de Edifícios, apoiada por uma aplicação informática denominada MEXREB. Completa-se o estudo com a análise dos resultados da aplicação da metodologia proposta a um conjunto de 39 edifícios, num total de 498 fogos, abrangendo um conjunto de 1.086 residente, que visa a sua validação.Tópico 1: Aspectos teóricos, históricos, legales, económicos y tecnológicos de la restauración y conservación de bienes patrimoniales

Reliability of in-situ diagnosis in external wall renders

This study focuses on the reliability of in-situ diagnosis performed on external rendered façades. This analysis was based on a set of parameters drawn from different visual observation, in-situ and laboratory testing techniques. The results were collected based on the previous inspections of 98 rendered façades of buildings and individual testing walls with different components, ages and degradation types. For that purpose, a reliability indicator was proposed and applied for better results interpretation of multiple testing techniques. In each case study, the parameters with higher reliability are defined. The final reliability indicator was established based on the average of three partial indicators, namely a reliability indicator for the established base criteria' uncertainty in laboratory testing (reference reliability indicator); a reliability indicator for the assessment techniques' uncertainty (verification method reliability indicator); and a reliability indicator for the results' uncertainty (number of the tests and their accuracy; reliability indicator of results obtained in-service). The reference parameters for each testing technique were synthesised. The relevant aspects, such as uncertainty associated with the reference parameter and type of verification method (quantitative, qualitative, and intervals), were defined. The analysis of the relationships between the parameters (exemplified for mechanical properties) and their correlation coefficients were assessed. Selection matrices were proposed that qualitatively identify the set of parameters that contribute to indirectly analyse the characteristics and performance relevant to the behaviour of the renders applied on façades. (c) 2020 Elsevier Lt

Strategies for school buildings refurbishment in Portuguese climate

Portuguese school buildings are generally characterized by an in-service thermal discomfort, due to the poor envelope thermal properties and the lack of resources for paying energy consumption. Most Portuguese schools are free-running buildings with a natural ventilation strategy. Hundreds of high and basic schools have not been refurbished and still have problems or anomalies and inadequate in-service conditions and need to be rehabilitated in the near future. There will be, therefore, an opportunity to apply the acquired knowledge of comfort, habits, energy consumption and costs that have been studied since the last refurbishments (2008). This work studies the Portuguese Brandão schools model (from the ’70s), including about 100 non-refurbished basic schools. A prototype classroom was prepared in a Brandão school, in Porto. The in situ experimental campaign consisted of temperature, relative humidity, CO2 concentration and energy consumption measurements. The main tasks of this work are: (1) the validation of an advanced hygrothermal model with experimental measurements before and after the prototype refurbishment; (2) development of a sensitivity study in order to choose the best refurbishment and heating strategies for these buildings, regarding their typology, the local climate features and the actual capacity to support the operating costs; (3) assessment of the roof insulation thickness in Brandão schools; (4) quantification of discomfort indicators.This work was financially supported by: Base Funding - UIDB/04708/2020 of the CONSTRUCT -Instituto de I&D em Estruturas e Construcoes - funded by national funds through the FCT/MCTES (PIDDAC). Francisca Cavaleiro Barbosa would like to thank FCT for financial support through the grant PD/BD/52658/2014

Is the time-domain reflectometry (TDR) technique suitable for moisture content measurement in low-porosity building materials?

Measuring moisture content in building materials is essential both for professional practice and for research. However, this is a very complex task, especially when long-term minor destructive measurements are desired. The time-domain reflectometry (TDR) technique is commonly used for soil moisture measurements, but its application in construction materials is considered a relatively new method, particularly for low-porosity building materials. The major obstacles to its current use in construction materials are (1) the difficulty of ensuring good contact between the TDR probe and the material, and (2) the lack of appropriate conversion functions between the measured relative permittivity and the moisture content of building materials. This paper intends to contribute to overcoming these difficulties by explaining in detail all the required steps to monitor moisture content in real-scale limestone walls. For that, a device is presented to guarantee the correct installation of the TDR probes on the walls, and a calibration procedure through the gravimetric method is proposed to avoid the use of an unsuitable calibration function developed for soil moisture measurements. In addition, the importance of the individual probe calibration is discussed, as well as TDR advantages and disadvantages for construction materials. The results obtained so far reveal that the TDR technique is suitable to detect moisture content variations in limestone, which is a low-porosity building material. (c) 2020 by the authors

An insulation thickness optimization methodology for school buildings rehabilitation combining artificial neural networks and life cycle cost

The energy efficiency of buildings, including public buildings, is a major concern for all European governments, since they are responsible for a large share of the total energy bill of the states. School buildings play an important role in these costs. The best strategy for reversing this scenario includes efforts on buildings retrofit, seeking to optimize their energy efficiency and indoor environmental quality. However, in the unfavourable economic climate we are experiencing, which requires great prudence when it comes to public investment, special attention should be given to this multi-objective optimization process. In this research, a methodology to optimize the insulation thickness of the external walls and roof on school buildings retrofit is proposed. The procedure includes the optimization of the building performance considering the following objectives: the minimization of the annual heating load; the minimization of the discomfort in the classrooms due to overheating; and the minimization of the life cycle cost of retrofitting external walls and roof. This methodology was applied to two Portuguese school buildings

Retrofitting Historic Buildings for Future Climatic Conditions and Consequences in Terms of Artifacts Conservation Using Hygrothermal Building Simulation

Funding Information: The first author acknowledges the FCT—Fundação para Ciência e a Tecnologia—for the financial support through the Ph.D. scholarship PD/BD/127844/2016. This work was financially supported by: UID/ECI/04708/2019- CONSTRUCT—Instituto de I&D em Estruturas e Construções funded by national funds through the FCT/MCTES (PIDDAC). The APC was funded by open access funds from Oslo Metropolitan University (OsloMet). Publisher Copyright: © 2023 by the authors.Climate change will greatly influence the world at several levels and will have consequences on the interior climate of historic buildings and artifacts conservation. Buildings are responsible for a large slice of the overall emissions, which is due both to the greenhouse gases that are released during their construction as well as the activities that are performed therewithin. One way of counteracting this trend is to design more efficient retrofit buildings and predict their behavior using simulation software, which can thoroughly assess the performance of new buildings or the impact of each retrofit measure for existing buildings. In this study, a calibrated computational model of high thermal inertia building was used to assess the performance of passive retrofits in mitigating the effects of climate change concerning artifact decay mechanisms. In addition, a methodology that aims to reduce the amount of time spent to perform these studies is also presented, in which time savings reach up to 63%.publishersversionpublishe

Measuring moisture content in building materials with Time-Domain Reflectometry: pros, cons and first results

n/

Current and future geographical distribution of the indoor conditions for high thermal inertia historic buildings across Portugal via hygrothermal simulation

Publisher Copyright: © 2023 Elsevier LtdMeteorological conditions play a major influence on the indoor conditions of buildings, especially in southern European countries, where the hygrothermal requirements are systematically neglected, on contrast to northern European countries. Outdoor conditions will greatly differ with a building's location, even more if climate change is considered. Designing or retrofitting should take the climate requirements and, if necessary, adapt appropriately. This paper presents a methodology that can easily assess the variance of the indoor climate or even the performance of a retrofit measure in accordance with location. The methodology encompasses five steps: 1) Set meteorological data; 2) Build outdoor weather files; 3) Obtain interface soil/slab temperature; 4) Obtain simulation outputs; and 5) Build map. This methodology is flexible in terms of location/region, computational model, requirements and weather data. A model of a historic church was used to compute current and future climates’ distribution for Portugal. It was shown that the indoor climates are more moderate on locations near the coast than on those in the interior of the country, and that the buffering effect is higher in the west coast than in the south coast. A significant increase in terms of indoor temperature from scenario RCP 4.5 to RCP 8.5 is expected. In most of the coastal zones, an increase in RH is expected in the near future, whilst in some interior regions, a decrease is expected. Finally, it was shown that when using an adequate interpolation function, the coarser grid can correctly simulate the geographical distribution of the indoor conditions.publishersversionpublishe