• Energy Research

A brief analysis of the environmental, social and economic paradigm of today's cities, allows a simple conclusion to be reached: current cities are not sustainable. Considering this, it is very important to study the causes of city problems and to develop city models implementing sustainability practices. There are a limited number of studies developing sustainable city models, but in the scientific community there is an even greater lack of studies about the rehabilitation of current cities to implement these models. This work emerges with the objective of analysing how it is possible to implement sustainability practices in cities through the development of a sustainable city model and an urban rehabilitation plan. The development of sustainable city models is a very complex topic and the analysis of the literature shows that it is necessary to consider the relation between environmental and social aspects in the development of sustainable cities, while taking special care when considering the economic ...

The need to reduce energy consumption in buildings leads to the development of new façade systems that can be energy efficient; thus, contributing significantly to heat transfer between outdoor and indoor spaces. Here, the versatility and flexibility of the modules are key attributes. For this purpose, this study focused on the thermal performance of Trombe walls and glazings and the glazing daylighting performance of a modular façade system in four different Portuguese cities. Computational simulations for the thermal performance of different arrangements of the modules were accomplished with the DesignBuilder software, while the glazing daylighting performance was studied by means of Ecotect and Desktop Radiance software, and compared with the transmittance curves of glazings. Occupancy profile and internal gains were fixed according to the Portuguese reality for both studies. The main characteristics considered in this research were the use of two double glazings, four different Portuguese climates and one or two Trombe walls in the façade. According to results, the use of Trombe walls and double self-cleaning glazing in the façade showed an important reduction in the energy consumption as well as better daylighting performance.

The implementation of energy efficiency measures into the existing building stock is essential to meet the 2020 targets set by the European Union (EU) Energy Performance of Buildings Directive (EPBD) and reinforced with the “EPBD-recast”. Thus, energy refurbishment of existing buildings is fundamental to achieve these goals. However, energy issues should not be the only concerns since the indoor environmental quality (IEQ) is also as important. When planning a building retrofit it is then necessary to consider the energy efficiency requirements as well as the IEQ. To do so, the main problems of the existing buildings should be identified. This work presents a study carried out in a large office building to identify the main pathologies related to the energy efficiency and to the IEQ. The main objective of this study was to characterize the actual situation of a building that represents a great number of the Portuguese office buildings in order to identify the principal problems that occurs in this type of buildings, to support the development of a refurbishment project of the building that can optimize both the energy efficiency and the relevant parameters to the IEQ and that are also solutions with potential to be used in other buildings.

PurposeThis research presents the development of a Building Passport for Sustainable Conservation (BPSC) as a questionnaire with a set of 23 core indicators, for a baseline assessment of heritage buildings. The aim of this tool is to identify priorities for future interventions, by recognising the contributions of heritage buildings to sustainability that should be preserved and the fragilities that need to be improved.Design/methodology/approachThe BPSC uses a selection of core indicators for sustainability observable on heritage buildings. It was applied to four different case studies of modern heritage in the Netherlands, to verify its applicability and limitations.FindingsThe results suggest that this tool has the potential to contribute to an expedite assessment, reaching consensual evaluations of priorities for sustainable conservation, while reducing the time and cost of the process, contributing to support informed redesign decisions.Originality/valueRecently, existing building sustainability assessment (BSA) tools have been adapted and new BSA tools developed for heritage buildings. Some tools target existing buildings, but seldom cover cultural significance and heritage values. Others target the after-redesign situations – aiming at assessing how sustainable the redesign is. Often BSA tools are complex and time-consuming, with extensive indicators and data requirements. The BPSC developed in this research covers the main aspects of sustainability and related heritage values, in a simpler tool for a baseline assessment.

Abstract Steel structures represent an interesting alternative to conventional construction solutions. Their characteristics can easily be highlighted when looking at construction sustainability principles, such as its durability, adaptability or recyclability. This paper compares the assessment procedure of three building sustainability assessment systems (BSA): SBTool PT -H, BREEAM's Code for Sustainable Homes and LEED for homes v4 when dealing with steel solutions. BSA tools are developed to independently provide an evaluation of buildings' sustainability performance considering different impact categories. However, these may not valorise all the possible benefits a construction solution can have due to weighing, calculation procedures' constraints and indicators addressed. The way these systems address steel sustainability advantages is discussed through their application to a case study single family building. This research work showed that existing BSA tools mainly focus on conventional construction and thus some sustainable benefits of other solutions can often be hardly acknowledged. To deal with sustainable construction aspects, in particular with steel construction, a systemic approach is needed, at early design stages to aid defining the sustainable building concept through tangible goals so to achieve the most appropriate balance between socio-cultural, economic and environmental fields.

Esta investigación aborda el estudio de fachadas con cristales de altas prestaciones y muros Trombe. El artículo presenta los resultados de la investigación en curso sobre un nuevo concepto en sistemas de fachada, denominado "Módulos de fachada para el acondicionamiento ecoeficiente de edificios", especialmente enfocado a la eficiencia energética de muros Trombe y módulos con doble acristalamiento. Haciendo uso del software DesignBuilder se realizaron simulaciones de una estancia, analizando distintos conjuntos de fachadas modulares. Para la realización de las simulaciones se consideraron dos tipos de módulos de doble acristalamiento, dos configuraciones de muros Trombe, tres climas diferentes en Portugal y cuatro orientaciones solares. Se compararon los requerimientos de calefacción de cada una de las configuraciones, observándose que tanto los muros Trombe como los módulos de doble acristalamiento presentaron disminuciones significativas en cuanto a requerimientos de calefacción. De las configuraciones analizadas, la mayoría presentó demandas energéticas de calefacción menores a lo especificado en la normativa portuguesa (RCCTE).

Abstract The development of new construction solutions is fundamental to enhance the building stock energy performance, and thus promote sustainable development in the building sector. These solutions must be sensitive to both the energy performance and the environmental performance. The aim of the work presented in this paper is the energy performance evaluation of non-conventional envelope solutions that were applied in a test building built at the University of Minho's Azurem campus. The evaluation was carried out by means of data analysis of in situ measurements, and also the use of energy and daylighting simulation tools. Prior to the simulations it was necessary to calibrate the model and create a climatic data file representative of the real weather conditions. From this evaluation it was possible to assess the potentialities of different construction solutions. The non-conventional solution presented a similar energy performance but a better environmental performance than the conventional solution, due to the use of lower embodied energy materials. It was also proved that, with minor modifications, the non-conventional solution can produce a better energy performance than the conventional one, evidencing the potential of application of these solutions.