Thermal analytical model of latent thermal storage with heat pipe heat exchanger for concentrated solar power

•Mathematical modeling of a thermal storage system with a HPHEX for CSP.•Investigation on the influence of the design variable of the LTES.•Prediction of the dimensions of a LTES that satisfies the primary design requirement.•Melting/solidification layer modeling.

An analytical model is developed for predicting the transient thermal behavior of a latent thermal energy storage (LTES) system in which circular fins are attached to the heat pipes. Thermal energy is stored or released by the heat pipe heat exchanger, and pure conduction is assumed for the charging and discharging modes. Considering the thermal environment required to concentrated solar power (CSP), potassium nitrate (KNO3), which has a phase-change temperature of 335 °C, is used as the phase-change material (PCM). Themal model used to estimate the heat transfer rate and the transient temperature variation in the PCM contained in each row of the heat pipe heat exchanger. Both melting and solidification are simulated under pure conduction. Row-by-row heat transfer is considered to assist estimation of row number of the entire LTES system. The developed model is also evaluated by comparing its predictions with the experimental results of a valid previous study. The discrepancies were observed to be less than 8%.