Dynamic modelling of ORC-based solar thermal power plant integrated with multitube shell and tube latent heat thermal storage system

In this paper, dynamic model for organic Rankine cycle (ORC) based solar thermal power plant integrated with latent heat thermal energy storage (LHTES) system is developed to understand its interaction with other components in the power plant for extending electricity generation after sunset. A multitube shell and tube latent heat thermal storage system is considered, in which phase change material (PCM) is stored in the shell side and heat transfer fluid (HTF) flows through the tubes. The multitube shell and tube latent heat storage is modelled considering an elemental unit obtained by encircling each HTF tube to the extent within which the surrounding PCM and HTF exchanges heat. A reduced order model coupled with the enthalpy technique is developed for analysing heat transfer in the LHTES system during charging and discharging periods. The model is validated with the experimental results reported in literature. Simplified transient energy equations are used to model collector and heat exchanger. Further, a latent heat thermal storage system is designed to generate 200 kWt after sunset and the overall performance of the solar thermal power plant is evaluated for ten days of operation under Indian conditions.