Improving buildings refurbishment through operative conditions evaluation

As EU existing buildings stock account for 40% of the total energy consumption, it is important to take measures to reduce these needs and, consequently, reduce the EU external energy dependency as well as reducing the greenhouse gas emissions, in accordance with what is prescribed in the EU Directive 2002/91/EU on Energy Efficiency in Buildings (EPBD) and reinforced with the "EPBD-recast". The implementation of energy efficiency measures in the existing building stock is necessary to meet the 2020 targets. Thus, energy refurbishment of existing buildings is essential to achieve these goals. However, during the buildings refurbishment, energy issues should not be the only concerns since the indoor air quality is also as important. When planning a building refurbishment it is then necessary to take into account the energy efficiency exigencies and also the indoor air quality. To do so, the main problems of the existing buildings should be identified, in order to do the right choices regarding the refurbishment project. This work presents a study carried out in a large office building to identify the main pathologies, related to the energy efficiency and also to the indoor air quality. The study encompasses an “in-situ” evaluation of the operating conditions, indoor air quality and air change rate. The main objective of this study was to support the development of a refurbishment project of the building that can optimize the energy efficiency, but also the relevant parameters to the Indoor Air Quality. The results showed that the building has a poor envelope thermal resistance, inadequate shading systems and also several problems regarding high concentration of some pollutants like CO2 or VOC

Portuguese EPBD based regulation put side by side with energy simulation tools

In 2002 EU implemented the Energy Performance of Buildings Directive which led to the revision of the buildings thermal codes. The transposition of EBPD into the Portuguese legislation was made through three regulations: RCCTE for residential buildings, RSECE for office buildings and SCE that establishes the energy labelling system. The national code RCCTE sets two methodologies for assessing the energy performance of buildings: a simplified methodology and a more detailed one, depending if it is an existent or a new building. It has been observed that since the entrance into force of these codes, the project teams are using the RCCTE methodologies as tools to estimate the energy consumption of buildings. In this work it was tested the accuracy of this approach, performing two studies: one where the energy needs obtained with the RCCTE methodology were compared with the ones obtained with a dynamic simulation tool; and another where the same energy needs were compared with the ones obtained with a simplified RCCTE methodology foreseen for existing buildings. With the studies performed it was verified that the RCCTE methodology is accurate enough, except for the coldest regions, where another kind of tool should be applied. The simplified methodology showed inaccurate results and must be used with caution. However, with some corrections, important improvements can be achieved

Definition of the energy performance requirements in rehabilitation projects

Building rehabilitation is essential to achieve the targets defined by the EPBD-recast regarding energy efficiency, reduction of carbon emissions and use of on-site renewable energy sources. To propose an effective building rehabilitation it is necessary to study the best combination of available options in terms of construction solutions, technical building systems (hot water, ventilation, heating, cooling and lighting), their cost, but also their impact on the thermal and acoustic comfort and indoor air quality of the building. Also, the definition of the cost-optimal level is essential, which is the minimum lifecycle cost (including investment costs, maintenance and operating costs, energy costs, earnings from energy produced and disposal costs) of each individual measure. In this work the multi-criteria decision analysis method ELECTRE III will be applied to balance all these aspects, during the design phase of a refurbishment project, in order to assist the design team on the selection of construction solutions and technical building systems. A simple case study is presented to demonstrate the feasibility of this approach in what concerns the definition of the energy performance requirements (e.g. thickness of insulation and efficiency of the heating system/air-conditioning system etc.), of a rehabilitation project. In this example several retrofit alternatives were studied, their implementation could lead to the reduction of the energy needs of the building from 13% to 83%. With this approach it was also possible to identify the alternative with the best global performance considering the investment costs, energy needs, indoor air quality, thermal comfort, and CO2 emissions

Polyphenols: a promising avenue in therapeutic solutions for wound care

In chronic wounds, the regeneration process is compromised, which brings complexity to the therapeutic approaches that need to be adopted, while representing an enormous loss in the patients’ quality of life with consequent economical costs. Chronic wounds are highly prone to infection, which can ultimately lead to septicemia and morbidity. Classic therapies are increasing antibiotic resistance, which is becoming a critical problem beyond complex wounds. Therefore, it is essential to study new antimicrobial polymeric systems and compounds that can be effective alternatives to reduce infection, even at lower concentrations. The biological potential of polyphenols allows them to be an efficient alternative to commercial antibiotics, responding to the need to find new options for chronic wound care. Nonetheless, phenolic compounds may have some drawbacks when targeting wound applications, such as low stability and consequent decreased biological performance at the wound site. To overcome these limitations, polymeric-based systems have been developed as carriers of polyphenols for wound healing, improving its stability, controlling the release kinetics, and therefore increasing the performance and effectiveness. This review aims to highlight possible smart and bio-based wound dressings, providing an overview of the biological potential of polyphenolic agents as natural antimicrobial agents and strategies to stabilize and deliver them in the treatment of complex wounds. Polymer-based particulate systems are highlighted here due to their impact as carriers to increase polyphenols bioavailability at the wound site in different types of formulations.info:eu-repo/semantics/publishedVersio

Acoustic evaluation of beam and pot slabs with lightweight regularization layers: a case study

The objective of this work is to evaluate the acoustic performance of beam and pot slabs with regularization layers made of lightweight concrete. The study consists on the analysis of the acoustic behaviour of three types of solutions, through the execution of "in situ" measurements for the determination of the airborne sound insulation index and of the impact sound insulation index. The studied elements have the same support element (concrete slab), but regularization layers made of different materials. The regularization layers studied were: concrete with granulated expanded polystyrene, concrete with expanded clay aggregates and cellular concrete. The acoustic performance of the three slabs is evaluated and compared with the performance of conventional solutions in way of evaluating their potentialities

Characterisation of lithium-based solid polymer electrolytes

Sol-gel derived poly(oxyethylene)/siloxane hybrids doped with lithium hexafluoroantimonate, LiSbF6, have been prepared. Compositions of these novel xerogel electrolytes were identified using the conventional d-U(2000)nLiSbF6 notation, (where n is the molar ratio of oxyethylene moieties per Li+ ion) and samples with n between ∞ and 2.5 were characterized by conductivity measurements, cyclic voltammetry at a gold microelectrode and thermal analysis. The electrolyte films produced were obtained as transparent and amorphous monoliths with encouraging electrochemical and thermal properties.Fundação para a Ciência e Tecnologi

Characterization of pTMCnLiPF6 solid polymer electrolytes

In this study the results our characterization of a solid polymer electrolyte based on poly(trimethylene carbonate), henceforth designated as p(TMC), and lithium hexafluorophosphate (LiPF6) are described. Samples of solvent-free electrolytes were prepared with a range of concentration of guest salt using solvent casting from tetrahydrofuran and characterized by conductivity measurements, thermal analysis and electrochemical stability. Electrolytes based on this host polymer, with LiPF6, were obtained as mechanically robust, flexible, transparent and completely amorphous films.Fundação para a Ciência e a Tecnologia (FCT

Performance evaluation of non-conventional constructions: case study in a temperate climate

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 comparison, in terms of energy performance, between heavyweight conventional solutions and mixed-weight non-conventional envelope solutions. These solutions were applied in a test building built at the University of Minho’s Azurém 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 weather 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 low 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

Characterization of lithium-based solid polymer electrolytes

Sol-gel derived poly(oxyethylene)/siloxane hybrids doped with lithium hexafluoroantimonate, LiSbF6, have been prepared. Compositions of these novel xerogel electrolytes were identified using the conventional d-U(2000)nLiSbF6 notation, (where n is the molar ratio of oxyethylene moieties per Li+ ion) and samples with n between ∞ and 2.5 were characterized by conductivity measurements, cyclic voltammetry at a gold microelectrode and thermal analysis. The electrolyte films produced were obtained as transparent and amorphous monoliths with encouraging electrochemical and thermal properties.Fundação para a Ciência e Tecnologia (FCT) - contracto POCI/QUI/59856/2004, POCTI/SFA/3/686, bolsa SFRH/BD/22707/2005, SFRH/BD/38616/200

Portuguese building stock indoor environmental quality “in-situ” assessment

Since the implementation of the Energy Performance of Building Directive, EPBD, in general, and the entrance into force of the respective Portuguese codes, in particular, buildings are requested to have better energy performances. However, during the buildings performance evaluation, energy issues should not be the only concerns since the indoor environmental quality is also as important. Thus, in this paper it is presented an “in-situ” evaluation of the Portuguese building stock regarding several parameters related to indoor environmental quality (IEQ), envelope thermal quality and operating conditions, natural illumination levels, thermal and acoustic comfort and indoor air quality. During the measurement campaign were evaluated several buildings that encompass different types of construction solutions, climatic zones and construction periods. One of the major objectives of this study was to support the development of building solutions that can optimize all the relevant parameters to the IEQ. Another important objective is the dissemination of the results through public entities, such as construction companies and design teams in order to influence the buildings projects to include other parameters than energy during the design process. Even though the measuring campaign is still in progress, there are already some preliminary results that show that, in average, the Portuguese buildings have a poor envelope thermal resistance, untreated thermal bridges, unsuitable natural illumination levels, several problems regarding high concentration of some pollutants like CO2 or VOC and also problems with acoustic discomfort due to an inadequate sound insulation