Design of a latent thermal energy storage system with embedded heat pipes

Thermal energy storage plays an important role in extending the operation of a concentrating solar power (CSP) plant to times when sufficient solar energy is unavailable for generation of electricity. Extending the CSP plant operation increases its capacity factor and can lead to reduction in the levelized cost of electricity equivalent to that of fossil-fueled power plants. In view of this, latent thermal energy storage (LTES) system embedded with gravity-assisted heat pipes is considered in the present study. Transient numerical simulations are presented and the influence of the design and operating parameters on the dynamic charge and discharge performance of the system is analyzed to identify operating windows that satisfy the U.S. Department of Energy SunShot Initiative targets, which include, storage cost less than $15/kWht, round-trip exergetic efficiency greater than 95% and charge time less than 6 h for a minimum discharge period of 6 h. Overall, this study illustrates a methodology for design and optimization of LTES with embedded gravity assisted heat pipes (HP-TES) for a CSP plant operation.