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Adequate school buildings are essential for the development of children, young people, and adolescents, as they must provide conditions that support their well-being and health. A healthy and comfortable indoor environment is critical for students’ performance in the learning process. This study aims to evaluate the indoor environment in kindergartens located in northern Portugal, with a primary focus on thermal comfort and indoor air quality. To achieve this, five buildings with varying construction characteristics were monitored, with temperature and relative humidity measurements taken in classrooms of different orientations over time. Additionally, the outdoor climate was also monitored. Based on the collected data, thermal comfort was evaluated using the adaptive model defined by the European standard EN 16798. Continuous monitoring of carbon dioxide concentration was also conducted in three of these buildings. The results reveal significant heterogeneity among the buildings, demonstrating the influence of construction characteristics on the interior thermal conditions. The recorded temperatures ranged from 10 °C to 27 °C, highlighting a substantial variability in performance across the different buildings. Particularly, the orientation and size of glazed openings, together with the lack of thermal insulation in the building envelope, especially in the roof, were found to have an important impact on the thermal comfort of the occupants. Furthermore, a relationship was observed between the daily maximum carbon dioxide concentration and the outdoor temperature, as a result of users’ efforts to minimize uncontrolled air infiltration, by limiting the opening of doors and windows, with consequences in the air exchange between the interior and exterior.

Innovation in construction plays a fundamental role in helping us face current challenges, namely the reduction in energy consumption, the mitigation of the effects of climate change, the depletion of resources, and the generation of waste. Regarding the built environment, improving the thermal properties of the building envelope is one of the growing needs to reduce energy consumption in the building sector. In this context, thermal mortars have been a trend in the construction industry in recent years due to their ability in reducing heat transfer through the building envelope. On the other hand, the addition of waste has been studied as an alternative to improve the thermal properties of mortars and reduce the consumption of primary materials in the construction sector. This work aims to carry out a detailed review regarding the incorporation of waste in thermal mortars through the application of scientometric data analysis and a systematic literature review. To this end, the different residues incorporated into thermal mortars and the various percentages and forms of incorporation were identified throughout the publications gathered in this review. The most studied properties regarding the thermal mortars with the addition of waste were also the subject of study. A comprehensive database of thermal mortars with the incorporation of waste is presented, in which the objectives of the studies, the wastes and forms of incorporation and the measured properties are highlighted. The main results of the analysed researches are deeply discussed and the gaps in this area of the knowledge are identified to point out new directions and possible perspectives for future studies in the field of thermal mortars incorporating waste.

In the 21st century, global energy security is a critical concern. Buildings contribute to over 40% of the worldwide energy consumption, primarily due to heating and cooling, resulting in a third of greenhouse gas emissions. The residential sector accounts for 25% of global electricity consumption, and in the Arab Mashreq and Maghreb (AMM) countries, the residential sector consumes around 41% of the total electricity. Existing residential buildings constitute a significant portion of the building sector, playing a crucial role in the overall performance of the building sector. To address this issue, it is essential to invest in the energy retrofitting of existing unsustainable residential buildings. This study aims to provide a comprehensive critical review of the literature on residential buildings’ energy retrofitting trends in the AMM countries. Using a keyword-based search, 41 relevant studies were identified and critically analysed to identify gaps in the literature, benchmarking against global retrofit studies’ trends, including the absence of top-down and bottom-up physical approaches and the limited use of modern tools like BIM. Additionally, there is a significant lack of studies that present measured and verified case studies of implemented energy retrofitting projects. The study concludes with recommendations for future research to bridge the gaps in the literature.

Dynamic thermal insulation systems (DTISs) can adapt to external environment conditions and help to reduce energy consumption and increase occupants’ thermal comfort, contributing towards the mitigation of overheating. DTISs adjust their configuration to optimize heat transfer through the façade. In this study, the performance of a DTIS was assessed through laboratory tests and numerical simulation. The DTIS is based on the ventilation of an air gap that facilitates the heat exchanges between the exterior and the interior. To extend the results of the experimental campaign, a set of scenarios was assessed based on numerical simulation. The results of the laboratory tests showed that the R-value obtained when the mechanical ventilation of the air gap is off (insulation state) is 3.89 m2.°C/W. In comparison, when it is on (conductive state), the R-value is 1.56 m2.°C/W, which corresponds to a reduction of approximately 60%. The results of the simulations showed that, when the shading system was on, the higher U-value was useful more than 50% of the time with discomfort, increasing to 75% when the shading system was off.

Although not a new concept, modular construction has been the target of increasing interest and investment in recent years. Modular wood construction systems have economic and environmental advantages, as wood is a natural and locally available raw material with interesting thermal properties. In this context, the BlueWoodenHouse Project, a closed cooperation project between academy and industry, aims to improve the actual knowledge of modular wood construction in Portugal. Among other objectives, the project aims to characterize the solutions, systems, and materials used in wooden modular construction, specifically in a modular wooden, single-family house in full use. Afterward, the house was monitored for 1 year (temperature, relative humidity, and CO2) and the data collected were analyzed and the interior thermal comfort was evaluated. The results of CO2 concentration monitoring indicate adequate air renewal rates, except for some periods in the bedroom, during the night. Additionally, application of the adaptive comfort model proposed by the EN 16798-2 standard resulted in a percentage of time in discomfort due to overcooling ranging between 31.3% and 38.6%. However, most of these periods may correspond to times when there is no occupancy of these spaces.

Infrared thermography (IRT) is often used to assess body temperature and can be useful as a diagnostic tool to detect human diseases. Despite this clear application in medicine, some studies can be found in the literature pointing to the use of IRT to measure body temperature as a parameter to evaluate thermal comfort inside buildings. However, there are still some issues that are understudied that this paper tried to address. For this purpose, an intensive experimental campaign was carried out, in which different combinations of temperature and relative humidity were implemented. Thermal images were taken of the face of a young adult, while the air temperature and relative humidity were assessed, as well as the body temperature, using traditional means. The results confirmed that different IR cameras and different ambient conditions (air temperature) impact the image resolution and definition. A linear correlation between the IRT results and the PMV was found for six subregions of the face. This correlation was higher in the forehead, cheekbones, and chin, and less interesting when measuring the temperature of the nose. However, if the overall temperature of the face is assessed, a good agreement between the PMV and the IRT results can still be found, indicating that the average facial temperature can be used as an indicator for the determination of thermal comfort. A prediction model for PMV based on IRT was proposed, with a root mean square error close to 0.70, when applied in a face temperature range between 28.9 °C and 34.4 °C.

High moisture content is a recurrent problem in masonry and can jeopardize durability. Therefore, precise and easy-to-use techniques are welcome both to evaluate the state of conservation and to help in the diagnosis of moisture-related problems. In this research, the humidification and drying process of two wall specimens were assessed by infrared thermography and the results were compared with two traditional techniques: surface moisture meter and the gravimetric method. Two climatic chambers were used to impose different ambience conditions to each specimen, to evaluate the impact of air temperature and relative humidity in the results. The qualitative analysis of the thermal images allowed the identification of the phenomena. The quantitative analysis showed that the order of magnitude of the temperature gradient that translates high humidity levels is substantially different in the two chambers, pointing to the influence of the surrounding environment. The presented analysis contributes to identifying the criteria indicative of moisture-related problems in two different scenarios and discusses the correlation between the non-destructive techniques and the moisture content in the masonry walls. The limitations and future research gaps regarding the use of IRT to assess moisture are also highlighted.

The high consumption of electricity in Palmas, Brazil is a direct consequence of the high temperatures identified throughout the year. Therefore, it is necessary to search for sustainable technologies that contribute to comfort through passive cooling, thus reducing the energy consumption. This work presents the results of an experimental campaign of 11 months, in which the effects of shading devices, the use of a low-emissivity reflective film, the implementation of natural ventilation and the application of reflective painting are evaluated, when applied individually and combined. The results show that when applied individually, natural cross ventilation was the most effective at night, while reflective painting showed better performance during the day. Regarding the combinations of techniques, the best combination occurred when reflective painting was used together with natural ventilation, and the result was a relevant improvement in the performance, ensuring high temperature reductions when compared to the control.

Non-destructive testing (NDT) describes techniques that measure properties of the body without disturbing their state [...]

Infrared thermography (IRT) is a technique increasingly used in building inspection. If in many applications it is sufficient to analyze the thermal patterns, others exist in which the exact determination of the surface temperature is a fundamental aspect. In these circumstances, the emissivity of the surfaces assumes special relevance, being probably the most important property in the definition of the boundary conditions. However, information on the uncertainty involved in its measurement, as well as the conditions that influence it, is scarce. This article presents an innovative contribution both to the characterization of the emissivity of various construction materials, and to the discussion of emissivity measurement procedures and the attendant uncertainty. In this sense, three experimental campaigns were carried out: T.I, preliminary tests to assess the initial conditions required for an accurate IRT measurement of the emissivity (reference tape and position of the camera); T.II, assessment of the emissivity of nine different building materials, in dry conditions, using the emissometer and the IRT and black tape methods; and T.III, assessment of the emissivity of three materials during the drying process. The results confirmed that emissivity is a crucial parameter for the accurate measurement of surface temperature. Emissivity measurements carried out with IRT (black tape method) and with the emissometer returned meaningful differences when compared with the values available in the literature. This disagreement led to surface temperature differences of up to 7 °C (emissometer versus reference values). This research also highlighted that the moisture content of the materials influences the emissivity values, with fluctuations that can be greater than 10%, and that the effect of moisture is visible even for low values of moisture content.

Infrared thermography (IRT) has become a commonly applied non-destructive testing method for assessing building envelopes. Like any diagnosis tool, IRT requires an appropriate experience and principle understanding, mainly when the method is used for quantitative analyses. The challenges of the IRT often deal with the dynamic properties of building partitions. Climatic conditions have a certain variability, and the accumulated energy storage in the building components can affect their temperature as well as the calculated thermal performance. This paper aims to analyze how stationary and dynamic regimes of a quantitative IRT test could impact the measured thermal transmittance of heavy multi-leaf walls. Investigation in two European countries with different climatic conditions are reported. In this way, it is discussed which boundary conditions should be guaranteed to provide reliable information about a building envelope using quantitative IRT. In order to check the quality of the measurements, the heat flux meter (HFM) method was also implemented, following the ISO 9869. The research revealed that it could be possible to use short-lasting tests in the climatic conditions of Southern Europe, while long-term tests should be implemented in Northern European countries where climatic conditions are less regular.

The measurement of ventilation rates is crucial in understanding buildings’ performances, but can be a rather complex task due to the time-dependency of wind and buoyancy forces, which are responsible for the pressure differences that induce air movement across the envelope. Thus, assessing air change rate through one-time measurements during brief periods of time may not be a reliable indicator. In this paper, the variability in the measurement of ventilation rates using the decay technique was evaluated. To that end, two compartments of a typical single-family detached dwelling were selected as a case study and 132 tests were performed, considering two different boundary conditions (door closed and door open). This work allowed the large variability of the results to be highlighted, as the coefficient of variation ranged from 20% to 64%. Wind speed had a key effect on the results, especially because during the measurements indoor–outdoor temperature differences were not so significant. The possibility of using occupant-generated carbon dioxide as tracer gas was also analyzed, but problems of cross-contamination were identified.

Moisture is one of the major causes of problems in buildings, and it can compromise their performance. Infrared thermography (IRT) is a non-destructive testing technology that can be used to assess the humidification phenomenon and, thus, prevent some of the problems caused by moisture. The images obtained by IRT reflect the thermal patterns of the surface under study and can be evaluated using a quantitative approach, which allows not only the traditional visualization of the thermal patterns but also quantification of surface temperatures and/or their differences. The relevance of this work is related to the discussion of the strengths and weaknesses of several methods to quantitatively assess the humidification phenomenon using IRT. For that purpose, the partial humidification by the bottom surface of a lightweight concrete specimen was considered as a case study. To evaluate the thermal gradients, the evolution of the thermal imaging throughout the measurement period and the definition of the areas particularly affected by moisture, a methodology that included a pre-processing phase for data reduction, followed by a data processing phase, were implemented. In the data processing, different statistical and numerical methods were tested. The results of the statistical descriptive analysis highlighted the time variation of the surface temperature, both when considering the entire specimen and when considering only specific areas. The variability of the temperatures at certain moments of the experiment could be observed in the box-plot representation. The image subtraction proved to be an interesting technique to quantify the temperature differences if the first image was used as reference. A thermal index, TI, was proposed to assess the cooling rate. The index highlighted the initial instant when the effect of moisture on the surface temperature was detectable.

Moisture is one of the major causes of building decay, compromising the indoor air quality and the durability of building components. Infrared thermography is a non-destructive technique that can be used to prevent damage caused by the presence of water. In this study, the potential of Principal Component Analysis (PCA) was assessed as a quantitative technique for processing the thermal images captured during 24 hours of water absorption by a lightweight concrete specimen. PCA showed that the first principal component is the one that better explains the phenomenon. The initial instant was the most interesting to identify the water level in the sample and the final instant allowed defining the first 8h as the most relevant.

Emissivity is a key parameter if one intends to use quantitative thermography. The importance of temperature, surface characteristics, wavelength and the direction of the emitted radiation in the emissivity is well documented in the literature. However, no research was found concerning the effect of moisture content. In this research, an experimental campaign was carried out with two main objectives: compare the emissivity value measured with an emissometer with the value measured with infrared thermography; assess the importance of moisture content in the emissivity value measured with an emissometer. A ceramic brick was used as an example case.