Chilled Water Storage Tanks: Stratification, Diffusers, and Energy Shifting A chilled-water storage tank only works as storage if the cold and warm layers stay separated. That is the whole game: stratification. Get the diffusers and geometry right and one tank stores hours of cooling; get them wrong and you pay for steel that behaves like a mixed, useless volume. This article covers the engineering. A chilled-water storage tank stores energy by holding a cold layer below a