Performance and cost multi objective optimisation of a shell-and-tube LHTES device for mid-temperature applications

In this contribution the authors investigated by means of an analytical approach the performance of a latent heat thermal energy storage varying the internal HTF tube distribution and other design parameters of the device. The work is based on a simplified prediction model of the discharging phase in order to span several configurations. The effects of the physical parameters of the phase change material and the geometrical dimensions of the device have been studied in order to suggest the optimal configuration. Indeed, the maximisation of the capacity together with the maximisation of the heat transfer rate are often competing and need a multi objective approach in the optimisation procedure. Here, the authors showed several optimal solutions proposing an efficient procedure that can be used in the selection of the most interesting cases to investigate by means of an experimental campaign or detailed numerical simulations. The approach proposed is general and it can be used also to minimise the cost of the device with respect to the maximisation of the performance due to the particular application. Several phase change materials were considered and a preliminary capital cost minimisation was proposed.