Fast calculation of latent heat storage process in the direct steam generation solar thermal power system using a POD reduced-order model

•Simulation based on the Lee model and enthalpy-porosity method was established.•Simplified two-dimensional axisymmetric model are applied for practical use.•The high calculation efficiency and accuracy of POD method is validated.•POD can quickly provide the field data and predict the unknown conditions.•The applicability and extensibility of POD algorithm are good. A Proper Orthogonal Decomposition (POD) reduced-order model for the latent heat storage process in a direct steam generation solar thermal power (DSG-STP) system is established based on the numerical simulation combined with the Lee model and enthalpy-porosity approach. Then, the computational accuracy and speed of the POD reduced-order model are examined by two unsteady-state cases. The research results show that the POD reduced-order model has good precision and fast computational speed. In the working conditions tested in this study, the relative mean error (RME) of POD-predicted temperature does not exceed 0.1% compared with the finite volume method’s results. Meantime, the POD calculation can improve the computational efficiency by hundreds of times (decrease from about 4 h to 45.865 s, about 314 times, for Case A). Thus, the POD reduced-order model has significant engineering value and is a promising means to accurately and efficiently solve the latent heat storage process in the DSG-STP system.