Chilled Water Storage TankChilled Water Storage Tank | Critical Facilities

Data centers use redundant systems for back-ups in case of an emergency. An HVAC chilled water storage tank adds an extra layer of redundancy to the process so if the chilled water plants crash the chilled water storage tank or tanks will provide a small cushion of time to allow the operating engineers time to straighten things out or in a worse case scenario allow time for the servers in the data center to be transferred to another data center and shut down.

Typically storage tanks will only allow for about 30 minutes to an hour before the data center floor reaches critical level and the servers need to be shut down. There are other applications for using chilled water storage tanks currently in use that save energy by storing chilled water in large thermal tanks for use during peak load times. During the day the stored chilled water is used instead of chillers. This reduces peak load saving money by utilizing the cheaper KW’s the utility company provides at night.

Chilled Water Storage Tank | Critical Facilities

Reduction in energy bills is the key however no ROI data is available to High Performance HVAC to show the cost effectiveness of thermal storage tanks. These systems are similar to the chilled water systems that utilize an ice storage system where ice is produced at night so in the day time the chilled water systems use the ice instead of mechanical cooling. Again, no ROI data is available so we cannot say what the effectiveness is except to definitively say it does reduce the cost of utility by utilizing load capacity at night instead of in the day during peak times.

The different types of chilled water thermal tank storage systems used are series, parallel, and stratified storage tank systems. Series tanks are piped in series with the decoupler piping where parallel are pipe in parallel with the chilled water loop piping. Series tanks can experience flow through issues where the water flows through the tank and temperature stagnation occurs in parts of the tank. Parallel tanks can experience mixing problems and stratification and stratified tanks requires special nozzles or diffusers to maintain appropriate flow and temperatures in respective zones of the thermal chilled water stratified tank.

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Chilled Water Storage Tank