Streamlined life cycle assessment of transparent silica aerogel made by supercritical drying

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• 作者：Mark Dowson^a ; ^c ; ^{mark.dowson@burohappold.com} ; Michael Grogan^b ; Tim Birks^b ; David Harrison^a ; Salmaan Craig^c
• 关键词：Silica aerogel ; Transparent insulation ; Life cycle assessment ; LCA ; Advanced glazing
• 刊名：Applied Energy
• 出版年：2012
• 期刊代码：2_03062619
• 类别：pw
• 出版时间：September, 2012
• 卷：97
• 期：Complete
• 页码：396-404
• 文件大小：1035 K

摘要

When developing sustainable building fabric technologies, it is essential that the energy use and CO₂ burden arising from manufacture does not outweigh the respective in-use savings. This study investigates this paradigm by carrying out a streamlined life cycle assessment (LCA) of silica aerogel. This unique, nanoporous translucent insulation material has the lowest thermal conductivity of any solid, retaining up to four times as much heat as conventional insulation, whilst being highly transparent to light and solar radiation. Monolithic silica aerogel has been cited as the 鈥榟oly grail鈥?of future glazing technology. Alternatively, translucent granular aerogel is now being produced on a commercial scale. In each case, many solvents are used in production, often accompanied by intensive drying processes, which may consume large amounts of energy and CO₂. To date, there has been no peer-reviewed LCA of this material conducted to the ISO 14000 standard.

Primary data for this 鈥榗radle-to-factory gate鈥?LCA is collected for silica aerogel made by low and high temperature supercritical drying. In both cases, the mass of raw materials and electricity usage for each process is monitored to determine the total energy use and CO₂ burden. Findings are compared against the predicted operational savings arising from retrofitting translucent silica aerogel to a single glazed window to upgrade its thermal performance. Results should be treated as a conservative estimate as the aerogel is produced in a laboratory, which has not been developed for mass manufacture or refined to reduce its environmental impact. Furthermore, the samples are small and assumptions to upscale the manufacturing volume occur without major changes to production steps or equipment used. Despite this, parity between the CO₂ burden and CO₂ savings is achieved in less than 2 years, indicating that silica aerogel can provide a measurable environmental benefit.