García Márquez, BeatrizPartal López, PedroNavarro Domínguez, Francisco JavierDelgado Sánchez, ClaraCuadri Vega, Antonio Abad2025-09-302025-09-302025García-Márquez, B., Partal, P., Navarro, F. J., Delgado-Sánchez, C., & Cuadri, A. A. (2025). Solid-to-solid phase change transitions to enhance solar heat storage of bitumen used in domestic hot water collectors. Construction and Building Materials, 495, 143681. https://doi.org/10.1016/j.conbuildmat.2025.1436810950-06181879-0526 (electrónico)https://hdl.handle.net/10272/27180The reduction of energy consumption in buildings requires the development of advanced thermal energy storage (TES) materials. In this work, the feasibility of TES materials to be applied in solar domestic hot water (DHW) collectors was evaluated. These TES materials are composed of bitumen (B) and different concentrations of pentaglycerine (PG), which act as supporting engineering material with high solar radiation absorptivity and solid-to-solid phase change material, respectively. Results indicate that these TES materials show good thermal stability, whereas their consistency improves as PG content increases over the whole temperature range at which a solar DHW collector operates. Interestingly, blend containing 30 wt% PG shows a high heat storage capacity (ca. 50 J/g), suitable thermal cycling reliability and excellent relative enthalpy efficiency (ca. 90 %). In addition, this binder also presents improved thermal properties (thermal conductivity and specific heat capacity). As a result, the heat charge/discharge performance evaluated by indoor thermoregulation tests leads to a Latent Heat Thermoregulation Index (LHTI) higher than those reported for other TES building materials. Therefore, B/PG blends may be considered a promising TES material for improving energy efficiency in solar DHW production.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Thermal energy storageSolid-solid phase change materialsHeat charge/discharge performanceSolar collectorProduct engineeringjournal article10.1016/j.conbuildmat.2025.143681open access3303 Ingeniería y Tecnología Químicas