Application Domain

The potential for cost-effective applica-tion of cool storage systems of one type or another exists in most buildings with a space cooling system. Originally, cool storage technol-ogy was developed for integration with chilled water cooling systems that typically serve larger buildings. More recent cool storage develop-ments have included technologies designed for integration with roof-mounted, direct-expansion (DX) cooling systems. Residential-sized cool storage technologies, including smaller versions of the equipment designed for the roof-mounted DX application, have also been developed, but cost economies-of-scale have been difficult to overcome in the residential market. Although originally developed to shift electrical demand to off-peak periods (from an electric utility’s perspective) and to take advantage of low-cost off-peak electric rates (from an end-user’s perspective), many applications can also result in lower first costs and/or higher system efficiency compared to non-storage systems. Therefore, while a large differential between on-peak and off-peak kWh charges or a high demand charge definitely improves cool storage economics, cost-effective applications also exist without these ben-efits. Still, not every cooling system pre-sents a cost-effective application, so care-ful consideration of site-specific condi-tions is warranted to determine whether cool storage makes sense or not, which cool storage technol-ogy is best, and the optimum configu-ration for a specific technology