Evaluation of analytical and numerical modeling for the design of thermal energy storage tube banks

This is the authors' abstract. We don't add key points for this paper.

Thermal energy storage (TES) in buildings is increasingly important for leveling out energy demand, enabling renewable energy and electrification. Cost-effective TES is essential for widespread adoption and ensuring energy benefits. Latent storage using phase-change materials (PCMs) is promising but limited to commercial systems. Encapsulating PCMs within tube banks has received limited investigation for residential applications, despite potential cost and simplicity advantages compared to alternatives like heat pipe modules or metal plate arrays. This study applies an analytical model to evaluate various configurations for residential TES systems, examining the effects of tube material, diameter, wall thickness, and spacing. Both organic and inorganic PCMs are considered, with trade-offs in properties and geometry discussed. Model predictions are validated against published data and supplemented with a two-dimensional (2D) finite-volume model to examine bypass flow and sensible heat. Results show that polymer tubes can perform similarly to metal tubes, small longitudinal spacing minimizes pressure drop, and transverse spacing with tube diameter primarily governs performance. The numerical model highlighted the wall spacing’s influence on bypass flow and melting times, demonstrating the need for uniform spacing between tubes and duct walls. The modeling framework developed provides a design process that can be adapted for a variety of applications.