Browsing by Author "Imbuluzqueta, Gorka"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
Item Accelerated aging test of solar reflectors according to the new AENOR standard – results of a round Robin test(American Institute of Physics Inc., 2018-11-08) Fernández-García, Aránzazu; Martínez-Arcos, Lucía; Sutter, Florian; Wette, Johannes; Sallaberry, Fabienne; Erice, Raquel; Diamantino, Teresa; Carvalho, M. João; Raccurt, Olivier; Pescheux, Anne-Claire; Imbuluzqueta, Gorka; Machado, Maider; Mancilla, Rodrigo; Richter, Christoph; SISTEMAS FOTOVOLTAICOS; Tecnalia Research & InnovationDurability tests of reflector materials for concentrating solar applications are crucial to guarantee the profitability of the plants and to ensure a proper efficiency during their lifetime. A standard including a set of five accelerated aging tests is close to be published by the Spanish standardization entity AENOR, within the sub-committee AEN/CTN 206/SC117. Under the framework of the STAGE-STE project, a Round Robin Test was organized by six partners to evaluate the comparability of results obtained in their respective laboratories after performing these durability tests. According to the results, in general a good agreement among the partners was found, with negligible to slight reflectance losses. In addition, it was noticed that the reference standard used in the reflectance measurements is of high importance. The conclusions of this work will help to improve the standard in future versions.Item Composite material incorporating protective coatings for photovoltaic cell encapsulation(2022-09-15) Yurrita, Naiara; Aizpurua, Jon; Cambarau, Werther; Imbuluzqueta, Gorka; Hernández, Juan M.; Cano, Francisco J.; Huerta, Irene; Rico, Elena; Caño, Teodosio del; Wölper, Sarah; Haacke, Florian; Zubillaga, Oihana; Tecnalia Research & Innovation; SISTEMAS FOTOVOLTAICOS; SGPhotovoltaic modules consisting of one back-contact cell were manufactured by vacuum resin infusion process using glass reinforced epoxy composite as encapsulant where the cells are embedded. Incorporation of three coatings onto the composite surface was studied with the aim to improve the electrical performance stability of the modules under ultraviolet (UV), thermal cycling and damp-heat environmental weathering. Photovoltaic and aging performance were examined through the short-circuit current density values and colour change of the composite. Decrease in the initial photovoltaic performance of the modules was caused by the coating deposition. The highest drop in the initial values was observed for the varnish type coating, showing a decrease of 2.6% in short-circuit current. Regarding the performance stability, the decrease was more pronounced in the damp-heat test, presenting the varnish type coating the minimum loss of 1.4% in short-circuit current and a variation of 87% in b* chromatic parameter after 1000 h exposure at 85 °C and 85% relative humidity. The study concluded that the protective coating should be selected to provide the composite modules with an optimal trade-off between the initial electrical performance and the desired stability, with further research work targeted to improve moisture barrier properties.Item Composite material with enhanced ultraviolet performance stability for photovoltaic modules(2019-09-15) Imbuluzqueta, Gorka; Yurrita, Naiara; Aizpurua, Jon; Cano, Francisco J.; Zubillaga, Oihana; SISTEMAS FOTOVOLTAICOS; SGThe present work aims encapsulating photovoltaic cells in glass reinforced epoxy composite by vacuum resin infusion, incorporating additives directed to enhance the performance stability of the manufactured photovoltaic modules under ultraviolet (UV) exposure. UV absorber (UVA) and hindered amine light stabilizer (HALS) additives were incorporated in the resin system in different content. Photovoltaic performance and stability under UV radiation exposure were studied through external quantum efficiency (EQE) spectra, chromatic coordinates and short-circuit current values. Decrease in current values and increase in yellowness were observed in the presence of UVA and HALS. However, an enhanced performance stability was observed when additives are incorporated, improving the stability when increasing the additive amount. The most stable module, with cells embedded in 2% additive containing composite, showed a 2.7% short-circuit current loss after UV aging exposure.Item Effect of organic precursor in hybrid sol–gel coatings for corrosion protection and the application on hot dip galvanised steel(2019-01-15) Agustín-Sáenz, Cecilia; Martín-Ugarte, Eider; Jorcin, Jean Baptiste; Imbuluzqueta, Gorka; Santa Coloma, Patricia; Izagirre-Etxeberria, Usoa; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOS; MATERIALES PARA CONDICIONES EXTREMAS; SISTEMAS FOTOVOLTAICOS; INGENIERÍA DE SUPERFICIESSol-gel coating material with enhanced corrosion protection for zinc-coated steel has been obtained through the incorporation of mono-phenol and bi-phenol organic precursors in an epoxide functionalised-silica-zirconia matrix. The effect of the presence of the organic precursors in the baseline formulation has been studied; sol stability has been examined by viscosity evolution; gel densification stage has been studied by differential scanning calorimetry (DSC); material composition has been analysed by Fourier transform infrared spectroscopy (FTIR) and X-ray spectroscopy (XPS); coating thickness and roughness has been measured by profilometry. Corrosion performance in three artificial weathering tests showed outstanding performance in the delay of zinc and steel corrosion products emergence, and electrochemical impedance spectroscopy (EIS) measurement permitted the identification of the coating presenting the most promising properties in terms of corrosion protection. Developed coatings have shown outstanding contribution to service life extension of zinc-coated parts.Item Feasibility of Storing Latent Heat with Liquid Crystals. Proof of Concept at Lab Scale(2016-05) Bayon, Rocio; Coco, Silverio; Barcenilla, Maria; Espinet, Pablo; Imbuluzqueta, Gorka; Hidalgo, Jokin; Rojas, Esther; SISTEMAS FOTOVOLTAICOS; VALORIZACIÓN DE RESIDUOSIn this work, the first experimental results of thermotropic liquid crystals used as phase change materials for thermal storage are presented. For that purpose, the n = 10 derivative from the family of 4-n-alkoxybiphenyl-4-carboxylic acids has been prepared. Different techniques like polarized-light microscopy, differential scanning calorimetry, thermogravimetric analysis and rheological measurements have been applied for its characterization. Having a mesophase/isotropic transition temperature around 251 degrees C, a clearing enthalpy of 55 kJ/kg, a thermal heat capacity of around 2.4 kJ/kg and a dynamic viscosity lower than 0.6 Pas, this compound fulfills the main requirements for being considered as latent heat storage material. Although further studies on thermal stability are necessary, the results already obtained are both promising and encouraging since they demonstrate de viability of this new application of liquid crystals as thermal storage media.Item Photovoltaic modules encapsulated in composite material modified with ultraviolet additives(2021-09-15) Yurrita, Naiara; Aizpurua, Jon; Cambarau, Werther; Imbuluzqueta, Gorka; Hernández, Juan María; Cano, Francisco J.; Zubillaga, Oihana; Tecnalia Research & Innovation; SISTEMAS FOTOVOLTAICOS; SGPhotovoltaic modules were manufactured by vacuum resin infusion process using glass reinforced epoxy composite as encapsulant where the cells are embedded. Incorporation of ultraviolet absorber (UVA) and hindered amine light stabilizer (HALS) additives to the epoxy resin was studied, given their potential to enhance the performance stability of the modules under ultraviolet (UV) radiation exposure. Photovoltaic and aging performance were examined through the evolution of external quantum efficiency (EQE) spectra, short-circuit current values and colour change. Decrease in the initial photovoltaic performance of the modules was observed, as evidenced in the short-circuit losses when additives are incorporated. Regarding the performance stability, increasing the content of both, UVA and HALS, leaded to improved results with lower short-circuit current loss and yellowness observed due to UV radiation. The most stable module, with cells embedded in 1% UVA and 1% HALS containing composite, showed a 2.8% short-circuit current loss after an UV exposure of 15.4 KWh/m2. UV protection enhancement was obtained in trade-off with initial photovoltaic performance, which should be considered when defining the additives and the amount to be used.