Pumped thermal energy storage

Pumped thermal energy storage (PTES) is recognized as one of the promising technologies to store electricity without geographical limitation or output power limitation. It uses a heat pump cycle to generate heat and cold energy, and uses a heat engine cycle to discharge electricity. The technology has drawn intensive research attention in recent years, and there is a couple of companies commercializing this technology. In this chapter, some fundamental knowledge of PTES is introduced. The basic thermodynamic cycles of Rankine PTES, Brayton PTES, and Transcritical PTES are presented with examples and their round-trip efficiencies are calculated. The recent research progress of different PTES cycles is summarized.