Recycling in buildings: an LCA case study of a thermal insulation panel made of polyester fiber, recycled from post-consumer PET bottles

摘要

Background, aim, and scope The interest in polyethylene terephthalate (PET) recycling is quite recent, but it has been growing steadily over the past few years. In this context, the aim of this paper is to assess the eco-profile, the energy savings and the environmental benefits of the use of recycled raw materials to manufacture products for thermal insulation of buildings in Italy (i.e., PET bottles post-consumer). Materials and methods The life cycle analysis is developed according to ISO 14040/44. In this paper, based on the LCA, the main types of environmental impact of a thermal insulation product have been outlined. This study is specifically focused on polyester nonwovens, produced by a company located in Italy. The cradle-to-gate life cycle inventory is performed for the mass of product needed to give a thermal resistance R of 1 (m~2 K/W). The calculation of the impacts is done with SimaPro software. With an environmental product declaration-oriented approach, a set of impact categories is used for the classification and characterisation of the life cycle impact assessment. Results The results of the impact assessment for 1 m~2 K/W of thermal insulation panels made with recycled PET are then compared with similar products made with virgin PET. The lower impact associated with the recycled PET for each category is underlined: the percentage reduction is around 46% in the GWP category. In the production process, the fiber-spinning phase results as the most relevant in terms of energy consumption. In addition, the energy saved when applying the thermal insulation in a building is estimated at 87 MJ/m2 per unit area per year in Rome. All the energy used during the production of a thermal insulation panel is recovered in about 2 years. Conclusions The product shows significantly low environ mental impacts thanks to the use of non-virgin PET, thus maintaining high mechanical and physical properties. If the recovery of PET from separate waste collection in Italy increases, this would reduce the share of waste PET purchased from foreign countries and would therefore reduce further the impact of transports for the production of the thermal insulation panel under investigation.