Superfície absorvedora solar a base de cromo: um estudo da emissão de gases de efeito estufa associado aos seus processos de fabricação

Abstract

Solar absorber surfaces (SAS) increase the absorption of solar radiation and reduce thermal losses by emission, and some stages of their life cycle require large amounts of energy, including thermal. Considering the concerns about climate change, this work aims to produce solar absorber surfaces, quantify and compare the greenhouse gas (GHG) emissions associated with their obtaining process with Black Chrome (CrxOy) application. To map the structure of the knowledge field, a bibliometric and network review was performed using the VosViewer software. The Life Cycle Assessment methodology and the IPCC 2013 GWP 100a environmental impact assessment method were used for determining GHG emissions. From experimental data obtained in the LABFILM and LACOM laboratories (UFPB) deposition techniques Sputtering were studied and the electrodeposition technique was compared. The evaluations were done in manufacturing processes that presented SAS with absorptivity higher than 90%. Four types of substrate treatment were considered. The study is pioneering in the production of SAS and the construction of inventories from their manufacture, quantifying and comparing GHG emissions for these manufacturing processes in Brazil. Emissions from SAS fabricated by Sputtering were 25,7g CO2-eq/process with substrate treatment by electropolishing. Emissions from comparative electrodeposition studies were 5,1g and 4,4g CO2-eq/process for bath 1 and bath 2, respectively. Considering electrodepositions comparing different substrate treatments, the emissions were 1,0 2,7 12,9 and 49,79g CO2-eq/process, respectively for hexane, citric acid, electropolishing, and heat treatment. when sputtering was performed with substrate treatment with isopropanol, hexane, and electropolishing, the emissions were 15,2 7,2 and 19,1g CO2-eq/process. Substrate cleaning by heat treatment accounted for the largest portion of emissions, due to the heavy use of electricity. It was observed that films deposited on electropolished substrates had the highest solar absorptions (≥ 95%), but higher emissions than treatments with hexane, isopropyl alcohol, and citric acid.