Latent heat storage (LHS) systems offer high energy density and stable operating temperatures, making them suitable for domestic hot water (DHW) and residential heating applications. This study presents a pilot‐scale thermal energy storage (TES) unit with a nominal capacity of 7.5 kWh, employing a modified salt hydrate phase change material (PCM) and novel aluminum T‐shaped fins designed to enhance heat transfer. Under realistic operating conditions, the system demonstrated reliable performance and long‐term stability, completing more than 260 charge–discharge cycles over several months of continuous operation. The integrated aluminum fins significantly improved thermal performance, reducing charging and discharging durations by 73.5% and 83%, respectively, while an average round‐trip efficiency of 85% was maintained. The pilot sustained thermal outputs of 3.4 kW for more than 80 min at discharge temperatures above 40°C. Increasing discharge power resulted in proportionally lower total heat extraction, indicating a near‐linear trade‐off between power output and usable heat. To complement the experimental evaluation, an environmental and economic assessment was performed using an hourly household‐level model and applied across several European locations. Compared with a conventional water‐based storage unit of equal volume, the PCM‐based system enabled higher utilization of rooftop photovoltaic (PV) electricity, reduced grid electricity consumption, lowered associated greenhouse gas (GHG) emissions, and decreased operational costs. These findings demonstrate that enhanced PCM‐based TES systems can provide both technical and sustainability benefits, supporting their potential role in future residential DHW applications.
Thon et al. (Thu,) studied this question.