Development of polyurethane rigid foam – phase change material composites with latent heat storage capacity for thermal insulation: Insights from the ECHO project

This study investigates the potential of polyurethane rigid foam – phase change material (PURF-PCM) composites for the thermal insulation of cooling thermal energy storage (CTES) systems, with a focus on residential applications under the Horizon Europe ECHO project. It addresses the pressing need for a smart functional thermal insulation composite designed for a sustainable, compact, and efficient CTES system of ECHO to reduce greenhouse gas emissions and improve energy efficiency in alignment with EU climate objectives. In PURF-PCM composite development, ethyl palmitate was utilized as the organic PCM component for latent heat thermal energy storage with a melting onset temperature of 21.3 °C, which was incorporated at different mass fractions inside the foam matrix. Differential scanning calorimeter, thermogravimetric analyzer and transient plane source thermal conductivity analyzer were employed to characterize the thermophysical properties of the composites. Physical characterizations were conducted using gravimetric leakage tests, optical microscope imaging and a mechanical analyzer. According to the differential scanning calorimetry analysis results, the PURF-PCM composites have a latent heat storage capacity of up to 23 kJ/kg. This study provides significant insights into the direct incorporation of an organic PCM as a latent heat storage medium in PURF and sets the stage for the pilot-scale production of PURF-PCM smart functional thermal insulation composites. These findings emphasize the potential of upscaling PURF-PCM fabrication using high-pressure polyurethane foaming machines and lay the foundation for future efforts in the utilization of PURF-PCM composites for thermal insulation of full-scale CTES units in energy-efficient residential applications.