Stratified Chilled Water Storage (SCHWS)
Thermal Energy (chilled water) is produced during periods of off-peak electrical demand (usually at night), collected in a thermal energy storage tank, and withdrawn and distributed through the facility during peak rate demand hours. Warm and chilled water enters and exits the tank through diffusers located at the top and bottom of the tank. These diffusers are designed to eliminate turbulence and provide a stable, sharply defined transition layer, or "thermocline", thus allowing for the natural stratification of warm water at the top of the tank and chilled water at the bottom.
Five Ways a Chilled Water Thermal Energy System Lowers High Energy Costs
- Reduce Demand Surcharges - Most commercial and industrial utility rates include a "demand charge" - a monthly surcharge based on the maximum kilowatts used by the individual customer during any peak rate period each month. A thermal energy storage tank allows customers to operate their chiller plant during the local utility's off-peak rate period, dramatically lowering the utility's peak rate demand surcharge.
- Lower usage rates - Many utilities have established "time of use" rates as a way of encouraging customers to use less energy during daylight hours. Operating chillers during the evening, when off-peak rates are in effect, lowers the cost of electricity used for cooling.
- Reduce Power Consumption - With thermal energy storage, chiller operation is shifted to evening hours, when ambient temperatures are cooler. As a result, chillers operating more efficiently and consume less energy for a given cooling load.
- Defer Capital Equipment Purchases - In both new construction and facility expansion projects, a thermal energy storage system is often a cost-effective alternate to purchasing expensive chiller plant equipment. By utilizing a Natgun TES tank, capital expenditure outlays can be deferred and future operating costs dramatically reduced for years to come.
- Lower Construction Costs - Some utilities offer substantial cash incentives and rebates to customers installing thermal energy storage systems.