Performance assessment and LCA of a PCM-based coating for residential buildings of the north-west Mediterranean region

The paper focuses on the thermo-economic and life cycle assessment of three different Phase-Change Materials (PCM) for use in residential buildings on the North-West Italian coast. For the purpose of this work, we considered the climatic conditions of the city of Genoa, Italy, and used publicly available weather data from year 2020. We numerically assessed three PCMs against conventional thermal insulating materials, on three different flat wall geometries, using a one-dimensional heat transfer model, implemented in MATLAB. The most relevant characteristic of PCMs is their phase transition condition. Our model is based on the assumption that PCMs transition occur in a specific temperature range, and this yields to an instantaneous increase of their specific heat. Subsequently, based on a 25-year PCM life cycle assumption, we carried out a thermo-economic analysis based on the Net Present Value (NVP) index, a life cycle assessment (LCA) and a carbon dioxide (CO2) saving estimation. Linear regression was used to predict the future economic and environmental scenarios. Simulation results showed that PCM performance is not as high as expected when benchmarked against a conventional insulating material. Specifically, PCMs do not reduce winter thermal demand and CO2 emissions over their life cycle are twice those of the classical insulator taken as a reference. We then numerically evaluated their performance in a warmer climate, corresponding to a South Mediterranean region, and under these conditions PCMs outperformed against conventional insulators, thus justifying their current higher cost.