The Wall-ACE project: an overview of the in-field monitoring on the novel Aerogel-based products

The increasing demand for high energy efficient buildings has lead to a growing interest in building envelope solutions characterised by an high level of innovation. The necessity of providing new solutions for the energy retrofit of existing and – especially – old and/or listed buildings is rising great challenges. A promising perspective comes from the implementation of aerogel-based Super Insulating Materials, which can provide added value with respect to current envelope technologies. In this framework, the ongoing EU H2020 research project Wall-ACE aims at developing a suite of Aerogel-based sustainable insulation solutions for the building market. The five insulation products under development were specifically designed for both the renovation of existing buildings and for the construction of new zero energy buildings. The aim is to achieve for each product a thermal conductivity significantly lower with respect to the state-of-the-art solutions. In this paper, an overview of the research activities which led to the development of these new high insulating products is presented. The products developed were tested through laboratory tests, numerical analysis, small scale and full-scale experimental activities. Thereafter, the different large-scale test facilities and the case study buildings selected in different EU countries (Italy, United Kingdom and France) to test the different products developed are showed

Standardized cross-linking determination methods applied to POE encapsulants in lamination recipe emphasizing

International audienceEthylene vinyl acetate is the most common encapsulation material in photovoltaic panels. Due to gradual engineering, it ensures to meet performance requirement of standard cells, low-cost and well understood cross-linking behaviour, both physically and chemically. Nowadays polyolefin elastomers (POE) have been entering the PV industry requirements by advanced cells concepts and/or novel degradation phenomena noticed on bifacial modules. POE exhibit several advantages based on its intrinsic high volume resistivity, low permeation, processability and most importantly, the absence of harmful by-products (such as acetic acid) generated upon humidity exposure[1, 2]. However, this new family of materials may behave differently from EVA during crosslinking, thus it is necessary to verify and adapt standard measurement methods. Therefore, the main objective of this study is to investigate the cross-linking behaviour of POEs with the final goal of exploring the process window of the lamination. The characterization methods like differential scanning calorimetry (DSC) and Soxhlet extraction have been used to determine crosslinking rate and chemical structure of several encapsulants. Similar to EVAs, cross-linking rate of POEs measured by Soxhlet extraction increases with lamination duration until reaching a plateau. The indirect cross-linking rate measurement by DSC analysis is usually favoured through its simple, fast implementation, absence of toxic chemicals when compared to Soxhlet extraction. Remarkable correlations between the two techniques were obtained for a commercially available POE, allowing the extension of the IEC standard to new encapsulants. Nevertheless, in the case of highly engineered materials, clear deviations are recorded, highlighting validity limits of direct correlation between Soxhlet and DSC methods

Standardized cross-linking determination methods applied to POE encapsulants in lamination recipe emphasizing

International audienceEthylene vinyl acetate is the most common encapsulation material in photovoltaic panels. Due to gradual engineering, it ensures to meet performance requirement of standard cells, low-cost and well understood cross-linking behaviour, both physically and chemically. Nowadays polyolefin elastomers (POE) have been entering the PV industry requirements by advanced cells concepts and/or novel degradation phenomena noticed on bifacial modules. POE exhibit several advantages based on its intrinsic high volume resistivity, low permeation, processability and most importantly, the absence of harmful by-products (such as acetic acid) generated upon humidity exposure[1, 2]. However, this new family of materials may behave differently from EVA during crosslinking, thus it is necessary to verify and adapt standard measurement methods. Therefore, the main objective of this study is to investigate the cross-linking behaviour of POEs with the final goal of exploring the process window of the lamination. The characterization methods like differential scanning calorimetry (DSC) and Soxhlet extraction have been used to determine crosslinking rate and chemical structure of several encapsulants. Similar to EVAs, cross-linking rate of POEs measured by Soxhlet extraction increases with lamination duration until reaching a plateau. The indirect cross-linking rate measurement by DSC analysis is usually favoured through its simple, fast implementation, absence of toxic chemicals when compared to Soxhlet extraction. Remarkable correlations between the two techniques were obtained for a commercially available POE, allowing the extension of the IEC standard to new encapsulants. Nevertheless, in the case of highly engineered materials, clear deviations are recorded, highlighting validity limits of direct correlation between Soxhlet and DSC methods

Identification of the hygrothermal properties of a building envelope material by the Covariance Matrix Adaptation evolution strategy

International audienceThis paper proposes the application of the Covariance Matrix Adaptation (CMA) evolution strategy for the identification of building envelope materials hygrothermal properties. All material properties are estimated on the basis of local temperature and relative humidity measurements, by solving the inverse heat and moisture transfer problem. The applicability of the identification procedure is demonstrated in two stages: first, a numerical benchmark is developed and used as to show the potential identification accuracy, justify the choice for a Tikhonov reg-ularisation term in the fitness evaluation, and propose a method for its appropriate tuning. Then, the procedure is applied on the basis of experimental measurements from an instrumented test cell, and compared to the experimental characterisation of the observed material. Results show that an accurate estimation of all hygrothermal properties of a building material is feasible, if the objective function of the inverse problem is carefully defined