Design a PCM-based thermal storage system for waste heat recovery in an industrial process operating at 150°C.

Design approach: PCM selection - erythritol (Tm=118°C, latent heat 340 kJ/kg) or HDPE (120-140°C) for this temperature range, considering congruent melting, cycling stability, and cost; Heat transfer enhancement - due to low PCM conductivity (~0.5 W/m-K), use finned tubes (10-20% fin volume), metal foam inserts (aluminum 10-15 PPI), or encapsulated PCM spheres (1-5cm diameter) for high surface area; System sizing - for 100 kWh storage: m_PCM = Q/(L + c_pΔT) ≈ 1000 kg considering sensible storage, container volume 1.5-2× PCM volume for expansion; Thermal resistance network analysis ensuring adequate charge/discharge rates; Material compatibility (corrosion, thermal stress); and Safety features (expansion volume, containment). Validate with 1D Stefan problem analysis or CFD with enthalpy-porosity method for phase tracking.