Ice Bear: Thermal Energy Storage for Smaller Buildings

First, some background. Thermal energy storage (TES) is a relatively simple cooling technology through which cooling capacity is generated at night using off-peak electricity to chill water or make ice; then that chilled water or ice is used during the daytime to cool a building. TES systems shift the primarily electricity use for cooling to off-peak hours. This can be a huge money-saver for a company that pays demand charges or has time-of-day billing rates. In most commercial buildings, cooling is the largest energy load, and nearly all of the cooling demand occurs during daytime hours, when electricity demand is highest (see left graph in Figure). Shifting the electricity demand for cooling to nighttime hours reduces the daytime peak demand, saving money (graph on right). The steady load of cooling the ice or water also typically allows downsizing of the chiller.