Multiscale analysis of a seasonal latent thermal energy storage with solar collectors for a single-family building

This paper presents a comprehensive system-to-CFD multiscale analysis of a seasonal thermal energy storage (STES) system based on phase change materials (PCMs) for efficient energy storage and release for space heating. The study investigates the impact of various factors, including the geometry of the individual storage tank and the thermo-fluid dynamic parameters of the heat transfer fluid on the system performance. The work focuses on STES integration with space heating system to meet the thermal energy demands of a typical single-family building located in Naples – South Italy, typical coastline Mediterranean climate. The primary goal is to assess the behaviour of the system-integrated PCM tank and its characteristic parameters, leading to the proposal of sustainable approaches that include renewable energy sources and partially fulfil the building thermal loads. Among the Scenarios, one stands out as it achieves a better operation, allowing storage and solar collectors to cover around 69.2 % of the winter heating demand, i.e., 3.06 MWh. The study also discusses the benefits of modular system operation, as evidenced by Scenario 3, which allows for the parallel discharge of multiple LHTES tanks, leading to an enhancement in efficiency compared to other Scenarios. Results indicate that the total energy discharged by a single STES is 56.30 kWh, with a latent heat fraction released over a time of 111 h and an average temperature difference of 5.65 ◦C. The tank efficiency reaches a value of 90.4 %, demonstrating the effectiveness of the STES system in meeting heating demands.