Thermal energy storage

Abstract This chapter describes the various technologies for storing thermal energy with their advantages and application examples. A prominent way of storing heat is using a heat transfer liquid. Single-tank thermocline and two-tank technologies are described for fluids including water, oils, and molten salts. Alternative to liquids, especially for higher temperatures, solid thermal storage has been used industrially and offers potential for low cost in new applications with tube-in-concrete and packed-bed technology detailed in this section. The design and calculation procedures of packed beds are introduced and trade-offs between size and efficiency along with the cyclic temperature profiles are discussed. A dual-media thermocline system is described that combines the advantages of solid and liquid thermal storage for higher storage density and lower cost. Besides technologies for hot thermal storage applications such as solar, electric storage, and heating, one section deals with cold storage technologies. Employed for refrigeration and air-conditioning applications, these use water and phase-change materials including ice to time-shift cooling demand and supply.