Thermal storage - the shifting of electric demand through the off-peak generation of cooling using a variety of storage media - is becoming an increasingly popular way for utilities and their customers to improve energy efficiency and reduce operating costs without having to install expensive new equipment. This work is an introduction to this technology, and a practical guide on how to evaluate, design, and maintain thermal storage systems. This text focuses on the value and application of thermal storage in both new and existing buildings. It covers the full range of mechanical systems commonly in use today, including ice systems, chilled water storage, and heat storage in aquifers. It also features case studies and a glossary of terms. A useful reference for HVAC engineers and designers, mechanical contractors, architects, building owners, and all others involved in the design, installation, or maintenance of HVAC systems.