N. Simões

• PhD - Civil Engineering
• Professor (Associate) at University of Coimbra | Itecons

Thermo-adaptive reflectance (TAR) opaque facades change their solar reflectance in response to temperature variations. This behaviour can be optimised to improve indoor thermal comfort by tailoring the transition temperature (TT), i.e., the temperature in which the solar reflectance changes. The study aims to identify which factors influence the su...

Buildings with double curvature façades are captivating architects and the general public. However, manufacturing of such façade panels through traditional moulding technologies requires that a single mould is developed for each panel geometry, leading to significant costs and lead times. This issue can be overcome by reconfigurable multipoint moul...

This study critically examines the impact of indoor air quality (IAQ) on occupant health in two critical care units (ICUs) at Jason Sendwe Hospital (JSH) and General Carrier de Mine Hospital (GCMH) within the Southern DRC metropolitan area, focusing on their impact on occupant health and well-being. Utilizing a mixed methods approach that includes...

3D printing (3DP), as an emerging technology in the construction industry, has the potential to solve the sector’s labour shortages and low efficiency, as well as helping to reduce its negative environmental impact. On the investigative path towards new construction solutions, the thermal performance of buildings must not be compromised. In additiv...

Currently, the construction sector is witnessing a growing demand for lightweight solutions, which can be justified by the need to adopt high-performance solutions and the fact that the industry is struggling with a shortage of skilled labour. In this sense, this study focuses on a novel and flexible building wall system, constructed using an innov...

A opção por janelas minimalistas é uma tendência arquitetónica que tem tido um franco crescimento no mercado nacional e internacional e que tem despertado o interesse de vários fabricantes por serem sistemas com um valor comercial apreciável, já que são tipicamente comercializadas para preencher vãos de grandes dimensões. O tipo de abertura é princ...

External thermal insulation composite systems (ETICS) are, in general, more likely to suffer from colonisation by fungi and algae than conventional walls, regardless of the nature of the biocide technology used. This results from the greater propensity of finishing coats applied on ETICS to develop surface condensation and, consequently , favourabl...

The global interest in nearly zero-energy buildings (NZEBs) has led to their establishment as mandatory building objectives in Europe for all new constructions starting in 2021. The principles outlined in the Energy Performance of Building Directive (EPBD) emphasize the significance of reducing energy demand through various energy efficiency measur...

Low-emissivity (low-E) window films are designed to improve the performance of buildings. These films can be applied to different glazing systems without replacing the whole window. For most of the existing windows, it is not possible to apply these films on the surfaces inside the cavity. Placing them on the outer surface is not usually recommende...

One of the most important properties of a glazing system is the solar heat gain coefficient (SHGC, or g-value) which quantifies the passive solar thermal gains. There are several standardized numerical methods of determining a window's g-value. However, the methods do not consider the glazing systems in real boundary conditions, and usually are sub...

Rooftop materials are fast evolving to provide superior user comfort and advantageous product life cycles, but current commercial waterproofing solutions are confronted with persistent quality anomalies that are caused by cracks and infiltrations, which reduce the overall durability and robustness of the roof structures. To address this problem, he...

3D printing (3DP) has the potential to drive the construction sector's shift towards automation. It offers the freedom to design custom solutions with complex and optimised shapes, while allowing the reduction of material waste and construction time. Research currently focuses on studying material composition and its fresh and hardened state proper...

Insulating glasses (IGs) are composed by glass plates entrapping a cavity filled with a gas sealed by perimeter spacers. This composition pretends to guarantee higher energy efficiency and airborne sound insulation in buildings. The structural performances achieved by these IGs is not normally considered in detail. In fact, in codes there is no spe...

An indoor climate impacts human comfort, well-being, and safety. Therefore, it remains an important topic since, nowadays, people spend a significant amount of time indoors. Additionally, as tropical geographical zones become more populated, urbanised, and industrialised, the energy demand for air conditioning will rise significantly. In terms of t...

One of the most important parameters that indicate the energy performance of a window system is the thermal transmittance (U-value). Many research studies that deal with numerical methods of determining a window’s U-value have been carried out. However, the possible assumptions and simplifications associated with numerical methods and simulation to...

High noise levels in hospitals can affect patients’ well-being, staff productivity, and medical error rates. This study measured noise in two intensive care units (ICUs) in the Democratic Republic of Congo (DRC). An occupant’s survey and a continuous field sampling were conducted in May and June 2021 in each ICU, using a T Tocas SL 1361 digital sou...

Green roofs are made up of several components, including those belonging to the waterproofing and drainage layers, substrate, and vegetation. Of these, the substrate is undoubtedly one of the most important layers of a green roof, contributing not only to the healthy growth of vegetation but also to the water retention capacity and thermal behaviou...

Climate adaptivity can be introduced into building envelopes without processors or external power by technologies that operate on an intrinsic mode, enabling the usage of their reactions to environmental stimuli in a positive way. Thirteen of these technologies, i.e. auto-responsive technologies (ARTs), were studied for climatic suitability on opaq...

The selection of windows with the lowest life-cycle environmental impacts in an early-design stage is important to minimize impacts of buildings. Hence, an environmental and cost streamlined life-cycle assessment (LCA) approach, incorporating probabilistic triage, has been developed to support early-decision making for selection of window materials...

Windows are challenging building components regarding their life-cycle performance, which are influenced by parameters that often present trade-offs between environmental impacts and costs. To support the selection of windows with the lowest environmental and cost impacts in an early-design stage of buildings, it is essential to identify the key dr...

This study presents an experimental and numerical investigation on edge thermal bridges effects in vacuum insulation panels. For this purpose, an experimental campaign was carried out using a guarded hot plate apparatus to determine the linear thermal transmittance between different types of panel joints assemblies. Numerical modelling under steady...

Low-emissivity (low-E) window films are designed to improve the thermal comfort and energy performance of buildings. These films can be applied to different glazing systems without having to change the whole window. This makes it possible to apply films to windows in old and historical buildings for which preservation regulations often require that...

In this paper, a novel laboratory test campaign to assess the hygrothermal performance of an external vacuum-insulation composite system is proposed and carried out on a large-scale specimen placed in a climatic chamber. The experimental procedure includes standard ageing cycles such as heat/rain, freeze/thaw and a new approach to simulate solar ra...

The lack of productivity in the Construction sector associated with its negative impact on the environment has long been calling for the adoption of a robust digital strategy that favours the automation of construction processes. The large-scale application of 3D Printing (3DP) has proved to bring greater manufacturing efficiency while reducing the...

As it becomes more and more relevant to renovate existing buildings with energy efficiency as top priority towards a nearly Zero Energy Building (nZEB) stock, the need for new super-insulation materials to penetrate the construction market increases. A promising option is to incorporate vacuum insulation panels (VIPs) into an External Thermal Insul...

This paper presents the onsite temperature monitoring of ETICS walls located in a Mediterranean climate, looking to compare different conditions and insulation materials. The walls incorporate several insulation products, including vacuum insulation panels. Different finishing coats and orientations were considered. Additionally, a 2D numerical mod...

Recent years have seen an increasing need to invest in smart, energy-efficient technologies in buildings to improve health and convenience for occupants and to reduce energy consumption and carbon emission impacts. Digitalization and developments in the information and communication technology sector play a critical role in improving the efficiency...

Solar and Trombe walls are envelope solutions that can contribute to reduce the energy consumption of the building sector. However, few studies have looked at their behaviour in warm/hot climates, particularly at avoiding and counteracting the overheating risk. This study therefore set out to assess how subtypes of the Mediterranean climate would a...

Green roofs are complex systems governed by intricate transport phenomena, which are frequently solved using simplified and empirical models. This paper describes a numerical model capable of solving the conservation equations that govern the unsteady nonlinear coupled moisture and heat energy transport through a multi-layer green roof composed of...

The embodied impacts of window materials can be considered as hidden impacts. However, as buildings have become more energy efficient, the impacts of the windows are recognized as being increasingly significant and have not been thoroughly analyzed. Thus, comprehensive analysis should be performed to inform the wise selection of energy-efficient wi...

Building Information Modelling (BIM) paved the way to better information management in the construction sector, simplifying and encouraging the advent of digital technologies and tools. The application of large-scale additive manufacturing (AM) is growing and therefore subject to intensive research – on account of its disruptive potential to revolu...

There is an increasing need for energy-efficient windows; however, these windows can have high embodied impacts and can be costly. This has not been thoroughly analyzed and the literature has mainly focused on the operational performance of windows. It is important to wisely select optimal windows that minimize energy consumption, costs, and enviro...

The global market trend for Vacuum Insulation Panels (VIPs) is projecting a significant increase in their uptake in the construction sector. This is mainly due to the uniquely high-performance properties of the ultra-thin insulation materials. This uptake, however, can potentially be hindered by the VIPs’ higher cost and environmental impacts when...

A key factor for achieving nearly-zero energy buildings is to reduce their energy demand using highly efficient thermal insulation materials, such as vacuum insulation panels (VIPs). Currently, the high investment cost of VIPs is hindering the technology penetrating the building market. However, their high thermal performance coupled with reduced t...

The purpose of this study is to explore the relationship between solar orientation, age (constructive characterization) and energy performance of Portuguese residential building stock and to assess the usefulness of exploring the Portuguese National System for Energy and Indoor Air Quality Certification of Buildings (SCE) database through multivari...

Green roofs are increasingly being used to improve the energy balance and stormwater management of buildings. This work examines the thermal behaviour, water drainage and vegetation growth of two green roof systems: a conventional system containing extruded polystyrene and polyethylene, and an alternative cork-based system. In the new system, an ec...

Auto-responsive technologies (ARTs) operate in an intrinsic mode undergoing reversible changes in one or more of their properties in direct response to external stimuli variations. The aim of this paper is to identify their potential use for the thermal renovation of opaque facades of buildings in order to reach climate adaptivity. Adaptive facade...

This paper sets out a three-dimensional (3D) boundary element method (BEM) formulation in the frequency domain to simulate heat transfer through a point thermal bridge (PTB) at a corner in a building envelope. The main purpose was to quantify the dynamic effect of a geometrical PTB in terms of distribution of temperatures and heat fluxes, which is...

The European Union aims to ensure that investment in energy efficiency measures is cost-effective. Thus, the minimum energy performance requirements of buildings must follow the so-called cost-optimal levels. It is known that the impact of a specific measure on the energy performance is affected by others measures when implemented simultaneously,...

The worldwide demand for energy efficiency calls for improvements in the thermal performance of buildings. As a result, there is a growing interest in the use of high-performance insulation materials such as vacuum insulation panels (VIPs). Due to their low thermal conductivity, high insulation levels can be achieved with thinner walls than is poss...

Green roof technology is increasingly being used to improve the energy and environmental performance of buildings. However, the description of the thermal behaviour of green roofs is very complex since it depends on several variables and relies on intricate phenomena. In this work the authors characterize a green roof system that replaces the conve...

The buildings sector is known to be one of the most significant consumers of energy. The Energy Performance of Buildings Directive (EPBD), recently replaced by the Directive 2018/844, aims to promote the improvement of the energy performance of buildings, including the need to set cost optimal levels of minimum energy requirements taking local clim...

The current European Energy Performance of Buildings Directive (2018/844/EU) aims at achieving a decarbonised building stock by 2050. Where buildings are constructed to better thermal standards, operational and embodied energy can be equivalent, meaning that it is imperative that embodied energy is considered when specifying optimal insulation stra...

This paper evaluates experimentally the water drainage and water storage capacity of insulation cork board (ICB), a natural material, applied as one layer of a green roof system. The apparatus that was designed and built to support and water the test specimens is described. The study examines ICB samples of different thicknesses and densities. The...

The European Union has proposed a common methodology to identify energy-efficient measures with the minimum global cost throughout the lifecycle. It is known that the energy impact of a specific measure is influenced by other measures in the same package, which affect its profitability. For this reason, the cost-optimal package cannot be a simple c...

h i g h l i g h t s Characterization of expanded cork used as an uncoated building solution. Mechanical and hygrothermal properties of standard and medium density expanded cork. Medium density expanded cork has a better mechanical performance. Medium density expanded cork is resistant to long-term external exposure. Medium density expanded cork is...

Os revestimentos cerâmicos de fachadas fazem parte do património arquitetónico e cultural de um conjunto alargado de países, nomeadamente os mediterrâneos e sul-americanos. Contudo, a aplicação de revestimentos cerâmicos surge muitas vezes associada ao aparecimento de anomalias, como por exemplo a ocorrência de eflorescências. O depósito inestético...

Improvement of the energy efficiency of residential buildings must ensure compliance with cost optimality criteria, assuming a specific lifespan of the building. At the same time, the energy retrofit of buildings ought to preserve their intrinsic architectural and heritage value. Portuguese residential buildings constructed before 1960 did not foll...

This paper evaluates the influence of the solar heat flux, temperature, and relative humidity on OSB and concrete walls covered with uncoated medium density expanded cork. A boundary element numerical model was used to simulate the coupled heat and moisture transfer through the multi-layer porous solid walls. The expanded cork hygrothermal properti...

A building materials’ properties have a great influence on its energy performance, and this is particularly true of the hygrothermal properties of the insulation material. The variation in moisture content generated by weather conditions can have a strong impact on heat transport. The phenomena involved are very complex and difficult to fully simul...

There is growing interest in implementing predictive maintenance techniques to buildings and structures and consequently there is a pressing need for research in effective non-destructive testing (NDT) tools. Infrared thermography (IRT) is a popular NDT tool that has been used in various areas. However, since most known IRT testing techniques have...

In this paper the dynamic thermal behavior of a Linear Thermal Bridge (LTB) in a wooden building corner is evaluated experimentally. The tests were performed in the laboratory using a calibrated hot box. The temperatures imposed on the external and the internal environmental sides were controlled by a climatic chamber and a heating system, respecti...

This paper presents a numerical model to simulate heat transfer by conduction in defective layered media, looking to contribute to the interpretation of thermographic results obtained in active Infrared Thermography (IRT) tests performed on building elements. The proposed model is developed to simulate 3D heat diffusion in a multilayered system con...

The promotion of more efficient and greener buildings and the reduction of energy consumption are among the priorities defined in the Europe 2020 Strategy. The potential of incorporating different types of waste and by-products in construction materials and solutions is relevant for achieving a more sustainable construction and use of buildings thr...

For high energy performance buildings is necessary that the building components, in particular those that constitute the outer casing, must ensure flexibility of the energy performance compared to reference different climatic conditions. In recent years, the industry, in collaboration with research centres, is developing multifunctional building co...

This paper presents a set of fully analytical solutions, together with explicit expressions, in the time and frequency domain for the heat conduction response of homogeneous unbounded and of bounded rectangular spaces (three-, two-, and one-dimensional spaces) subjected to point, line, and plane heat diffusion sources. Particular attention is given...

The awareness of users about the benefits provided by the energy retrofitting of buildings is mostly related to the measurable return on investment in each energy efficiency measure. The environmental and economic assessment of the benefits depends on the quality of information (which usually has to be collected for each case). However, in the abse...

Infrared thermography (IRT) has proven to be a powerful non-destructive technique and it has been successfully used for detecting defects in a wide range of applications and sectors. Numerical modeling of heat transfer and diffusion in the presence of defects combined with experimental IRT results may be used both to detect and characterize existin...

The analysis of surface temperatures in constructive elements using infrared thermography can be a useful tool for the in situ identification of constructive details and materials and for the evaluation of their thermal behaviour. It is therefore very important to be able to predict the effect of the materials’ thermophysical properties on heat dif...

The EU-28 is anxious to ensure that the minimum energy performance of buildings does not deviate from the cost optimality criteria established for energy efficiency measures. These measures should include different improvement solutions for the building envelope, HVAC systems and also consider the contribution of renewable energy sources (RES). The...

This study analyses the economic profitability of solar water heating and biomass systems in single-family houses built before 1960. We examined several energy efficiency packages where insulation is applied to the envelope and systems are installed that provide hot water for both sanitary use and heating. The methodology suggested by the Directive...

An External Thermal Insulation Composite System (ETICS) kit may include anchors to mechanically fix the insulation product onto the wall. Using this option increases safety when compared to a simple bonded solution, however, it is more expensive and needs higher labor resources. The insulation product is then coated with rendering, which applied to...

This paper compares experimental and heat transfer modeling results for thermography applications in building elements. Over the years most building envelope inspections using infrared thermography (IRT) have been focused on qualitative analysis using mostly passive thermography techniques. However, increased need for the monitorization and assessm...

O aglomerado de cortiça expandida (ICB) tem-se revelado uma solução com potencial para ser usada como revestimento exterior de fachadas e coberturas de edifícios novos ou sujeitos a reabilitação. Com o intuito de garantir o uso adequado do ICB, as empresas Amorim Isolamentos e Saint Gobain Weber têm vindo a desenvolver, juntamente com o ITeCons/UC...

This paper proposes and validates, numerically and experimentally, an iterative model to evaluate the thermal resistance of multilayer walls in a dynamic state.The paper first presents the analytical solution for simulating heat conduction in the frequency domain. The model is then modified by assuming a single-layer wall with unknown thermal prope...

With regard to the requirements of European Union is necessary to implement effective measures for reducing energy consumption in buildings. It is essential to promote energy efficiency using new construction technologies that contribute to the limitation of energy consumption and that are more sustainable due to the nature of the materials and to...

User awareness about the benefits provided by the energy retrofitting of buildings is mostly related to the measurable return on investment of each energy efficiency measure. The environmental and economic assessment of the benefits depends on the quality of information (which usually has to be collected case-by-case). However, in the absence of da...

Improving the building envelope is relevant to increasing energy efficiency. Energy rehabilitation must meet cost optimality criteria during the life cycle of the building. The interaction between the cost of insulation (which depends on the thickness) and cost of operation is crucial to the cost optimality calculations. This work examines the infl...

A melhoria da envolvente dos edifícios de habitação existentes tem particular relevância no aumento da eficiência energética e consequentemente, na redução dos consumos e melhoria do conforto térmico. A reabilitação energética deve atender critérios de rentabilidade económica associada ao ciclo de vida útil estimado para os edifícios. A relação ent...

Energy retrofitting of historical buildings may contribute to the environmental sustainability of the building stock and also promote economic attractiveness to achieve optimal levels of profitability for retrofit investments. This paper aims to develop an integrated cost optimality and environmental analysis by combining alternative retrofit packa...

In this paper we analyse the influence of linear thermal bridges (LTB) on the overall thermal performance of the building envelope. Two different models are used: a 1D heat transfer model that does not take into account the 2D dynamic heat flow through the LTB, and a 2D heat transfer model that computes the energy through the LTB. The first is used...

Thermal bridges need to be considered in the building design phase to minimize heat loss and prevent building pathologies generated by moisture condensation. The linear thermal bridge (LTB) is normally taken into account at the building design phase, assuming steady-state conditions. However, thermal bridging analysis should involve the variation o...

Bonding defects in adhered ceramic tiling systems are common building pathologies that should be identified at an early stage. Active thermography technique is a diagnostic tool that may be explored to detect those bonding defects and that can also provide accurate information for its maintenance and repair. However, when applied to civil engineeri...

The paper deals with the application of passive thermography as a diagnostic tool to detect and evaluate bonding defects in adhered ceramic tiling. The bonding failure is a common building pathology and it represents serious risks to people’s safety, particularly when it occurs in external cladding coating systems of tall buildings. In the first st...