Optimum integration of latent heat storage in a solar thermal system for industrial processes: In series or in parallel?

Solar thermal energy holds great potential in decarbonizing the process industry to achieve net-zero emissions. This study focuses on analyzing the optimum integration of latent storage in solar heating and cooling for an industrial process, by comparing two configurations. Configuration 1 connects the thermal energy storage (TES) in parallel with the solar collector and the process, allowing the solar collector outlet stream to be directed to either the TES or the process. Configuration 2 connects the TES in series with the solar collector and the process, ensuring that the solar collector outlet stream always passes through the TES before reaching the process. The solar system also includes a rotary Fresnel collector that supplies heating and cooling to a dairy factory. The two configurations are evaluated by dynamic simulations including transients such as clouds and start-ups. The findings reveal that the parallel layout needs more components to achieve the same controllability and energy supply level as the series layout. Consequently, the parallel layout incurs a higher cost and complex operation. Considering the objective of finding a cost-effective and straightforward solution for the industry sector, the study concludes that connecting the TES in series represents the optimal configuration.