Energy Storage Systems

Abstract

This chapter explores thermal energy storage (TES) systems as a demand-side strategy for managing energy costs in buildings by shifting cooling loads to off-peak periods. Focusing on cooling capacity storage, it examines how TES leverages utility rate structures and enhances chiller efficiency to reduce operational expenses. The chapter details full and partial storage systems, comparing their design, cost, and performance in an example office building with a peak load of 510 tons and a daily cooling requirement of 6123 ton-hours. Full storage eliminates on-peak chiller use, while partial storage supplements it, offering flexibility and lower initial costs. Storage mediums - chilled water, ice, and eutectic salts - are analyzed for capacity, efficiency, and spatial needs, with calculations showing chilled water requiring 27,484 cubic feet for 1715 ton-hours, ice needing less volume due to latent heat, and eutectic salts balancing efficiency and space. Economic analysis estimates summer savings using a hypothetical rate schedule, highlighting additional utility incentives. Integration with district cooling systems is discussed, noting enhanced efficiency and reliability, but also infrastructure challenges. The chapter concludes that TES, especially with advancing technology and district cooling, offers significant cost-saving potential, contingent on proper system design, utility rates, and space considerations.