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- Desenvolvimento de uma tinta espectralmente selectiva sensível à espessura (TSSS) para sistemas de conversão fototérmicaPublication . Alves, Isabel N.; Soares, Elsa; Carvalho, Maria João; Cunha Diamantino, TeresaRESUMO: As tintas espectralmente seletivas surgem como alternativa aos revestimentos seletivos obtidos por métodos de deposição a vácuo para sistemas de energia solar térmica. Um dos benefícios da sua utilização é a possibilidade de recurso a técnicas de aplicação e manutenção mais simples, disponibilidade comercial a mais baixo custo e elevada durabilidade/proteção anticorrosiva. Existem apenas algumas tintas comerciais capazes de produzir revestimentos com elevado desempenho ótico e simultaneamente elevada estabilidade térmica. É urgente o desenvolvimento de soluções que evitem a diminuição da absortância solar e o aumento da emissividade térmica destes revestimentos e que simultaneamente não comprometam o desempenho anticorrosivo. Este trabalho apresenta o desenvolvimento de uma tinta seletiva cujas características se enquadram neste tipo de revestimento seletivo, a serem aplicadas em sistemas de energia solar térmica para baixas-médias temperaturas, visando a melhoria do desempenho destes sistemas no que respeita tanto às propriedades óticas dos revestimentos, como à durabilidade de materiais e tempo de vida da tinta, considerando matérias-primas comercialmente acessíveis e técnicas de aplicação mais simples.
- The importance of developing accelerated tests on the reliability of solar absorber and solar reflector coatingsPublication . Cunha Diamantino, Teresa; Gonçalves, Rita; Páscoa, Soraia; Alves, Isabel N.; Carvalho, Maria João; Fernández-García, Aránzazu; Wette, Johannes; Sutter, FlorianABSTRACT: Selective absorber coatings for solar thermal collectors and reflector coatings for Concentrating Solar Power (CSP) plants are the key components of these technologies and their durability is one of their most important characteristics. They should be low cost and withstand 20-30 years under different kinds of environments without significant loss of optical performance. Commercially, there are different physical vapour deposition (PVD) coatings for aluminium absorbers and reflectors. Results obtained with two commercial PVD solar absorber coatings (SA) and two solar reflector coatings (SR), under different accelerated aging tests (AAT), are presented and correlated with outdoor exposure. An Outdoor Exposure Testing (OET) site with maritime and industrial influence was used for an exposure campaign of the absorbers and reflectors for two years. Alternative artificial aging tests are proposed for absorbers and reflectors that better reproduce the corrosion mechanism obtained in natural conditions with maritime and industrial influence. The characterization of the coatings and degradation mechanisms of different aluminium absorbers and reflectors were evaluated optically, morphologically and chemically. The results obtained in an atmosphere with high corrosivity as in marine and/or industrial areas are a reliable way to verify the corrosion resistance of new materials in a short time and are a valuable tool to validate the different methodologies of accelerated aging tests.
- Protection of Steel Structures against Fire and Corrosion by Paint Coatings: A comparative studyPublication . Ferreira, Cristina; Gonçalves, Rita; Alves, Isabel N.; Vieira, Ana; Donato, Mariana; Morgado, Vanessa; Silva, Helena; Cristino, Ana Filipa Russo de Albuquerque; Nunes Soares, Tiago Diogo; Barreiros, Maria Alexandra; Cunha Diamantino, TeresaABSTRACT: Steel structural systems in modular construction must be protected against corrosion and fire exposure. The durability of both protective properties plays a key role in ensuring long-term service life and minimizing maintenance costs. The present work aims to validate anticorrosive protection systems for steel structures, with and without fire protection properties, evaluating degradation mechanisms and assessing the compatibility of intumescent layers with anticor-rosive coatings, in terms of their impact on corrosion resistance and fire protec-tion properties.
- Dielectric UV filters for protection of fire-resistant glass based on intumescent layersPublication . Silva, Ricardo Magno Lopes; Hashim, Hurraira; Roy, Deepto; Oliveira Fernandes, Carolina; Oliveira, Kevin; Leitão Pinheiro, Xavier Alexandre; Esteves, M. Alexandra; Capelo, Anabela; Donato, Mariana; Oliveira, Fernando; Ferreira, Cristina; Alves, Isabel N.; Cunha Diamantino, Teresa; Barreiros, Maria Alexandra; Rocha, Jorge; Passos Teixeira, Jennifer; Salomé, PedroABSTRACT: Structures such as OLEDs, perovskite solar cells, intumescent glasses, and other components in modern devices and buildings contain materials suscep-tible to degradation when exposed to UV radiation, requiring protection to with-stand outdoor environmental conditions. In this work, multilayer coating config-ured as a Bragg Reflector on glass is employed as spectral filtering to protect the intumescent component of fire-resistant glass from degradation due to prolonged UV solar radiation exposure. By alternating low-n (SiO2)/high-n (TiO2) dielectric layers through spin-coating, precise control over film thickness could be achieved, allowing the fabrication of thin (<700 nm) UV filters with high trans-mission of visible sunlight – 88% of the 780 to 380 nm wavelength range – while reflecting almost all the incident UV – 90% of the wavelength below 380nm. Using relatively simple techniques, high precision coating was successfully achieved, resulting in an effective UV radiation protective barrier applied to en-hance the durability of the components in fire-resistant glass.