Evaluation of the manufacturing processes for solar selective surfaces based on CrxOy from a carbon footprint perspective

Abstract

Solar selective coatings can improve the performance of solar collectors by reducing heat losses by thermal radiation, so that the surface selectively absorbs solar radiation with wavelengths specific to solar thermal conversion. The demand for low carbon and more sustainable products has evolved rapidly in recent years and selective surfaces are expected to play an important role in the development of solar energy technologies. The objective of this study is to assess the production process of selective surfaces with Black Chrome (CrxOy) obtained by two deposition techniques (sputtering and electrodeposition), using the Life Cycle Assessment (LCA) methodology. To this end, real data were collected from experiments, and detailed inventories of energy and material flows were built to support a LCA that quantified the carbon footprint of each manufacturing process. Per process, the results demonstrated that electrodeposition presented a higher overall carbon footprint (16.912 g CO2-eq) than sputtering (14.271 g CO2-eq). Electricity consumption associated with both processes was responsible for a significant share of the total carbon footprint: 77% for the electrodeposition technique and 59% for sputtering. The prospective LCA presented herein helped identify the hotspots of the processes that have margins for improvement, providing guidance regarding process upscaling.

Keywords

• Selective coatings
• Life cycle assessment
• Greenhouse gas emissions
• Black chromium
• Deposition techniques
• SDG 12