Ice bank
Also known as: ice storage, ice water tank, ice builder
Short definitionA tank that stores cooling as ice. Ice forms around its pipes over several hours; at the moment of need the melting ice supplies water at 0–1 °C, and a small unit copes with a large, short-lived load.
A dairy is the typical example: milk arrives twice a day, in a short time, and has to be cooled at once. If the unit is selected for that peak, the machine stands idle most of the day. Instead a small unit runs for a long time and builds ice in the tank. At load time the tank water is pumped to a plate heat exchanger, and the warmed return water hits the ice and cools again. Melting one tonne of ice gives roughly 93 kWh of cooling.
Dough water for a bakery, immersion chilling in a poultry plant and hydrocooling of fruit and vegetables are handled the same way. When sizing the unit, ask in how many hours the ice is to be built; building it on the night tariff lightens the bill. Ice is not grown thicker than 25–40 mm, because as it thickens it insulates the pipe and drags the evaporating temperature down. The tank gets an agitator or air bubbling, otherwise the leaving water warms up. If the tank is poorly insulated the stored ice melts by itself.