Expanding the envelope for indirect/direct evaporative data center cooling using thermal energy storage

The current philosophy in the design of data center cooling systems matches installed cooling capacity to peak cooling demand at the most challenging ambient condition. This “design point” typically occurs only briefly during hotter months. Cooling capacity remains under-used most of the time. An indirect/direct evaporative cooler with thermal energy storage allow a reduced installed cooling capacity to meet the same need and extends the upper temperature limit. Stored cooling capacity enables load-leveling, or peak-shaving, of cooling demands. Phase change materials present a potential for thermal energy storage to achieve load-leveling at moderate cost. In addition, during days of moderate temperatures thermal energy storage can extend free-cooling capacity when evaporative cooling would otherwise use water. Indirect/direct evaporative coolers that incorporate thermal energy storage can extend the operational envelope beyond current limits and reduce water consumption.