Kelvion New Plate Heat Exchanger

New Schneider Electric research details how utilizing higher chilled water temperatures in a data center environment results in energy savings of between 41% and 64%, whilst driving significant improvements in PUE.

The data center cooling function in general, and the operation of water chillers in particular, are large consumers of power and as such, require focused efforts to improve overall data center energy efficiency, says Schneider Electric. That’s why the global vendor commissioned this study, the results of which can also be found in this whitepaper: White Paper #227, How Higher Chilled Water Temperature Can Improve Data Center Cooling System Efficiency.

Water chillers would account for between 60 and 85% of overall cooling-system energy consumption. Consequently, data centers are designed, where possible, to keep usage of chillers to a minimum and to maximize the amount of available ‘free cooling’, in which less power-hungry systems such as air coolers and cooling towers can keep the temperature of the IT space at a satisfactory level.

One approach to reducing water chiller energy consumption is to design the cooling system so that a higher outlet water temperature (CHW) from the chillers can be tolerated while maintaining a sufficient cooling effort. In this way, chillers would consume less energy by not having to work as hard, and the number of free cooling hours can be increased.

As with any complex system, attention needs to be paid to all parts of the infrastructure, as changes in one area can have direct implications for another, stated Schneider Electric.

Whitepaper

Schneider Electric’s White Paper 227 details two real-world examples in differing climates; the first is in a temperate region (Frankfurt, Germany) and the second in a tropical monsoon climate (Miami, Florida). In each case, data was collected to assess the energy savings that were accrued by deploying higher CHW temperatures at various increments, whilst comparing the effect of deploying additional adiabatic cooling.

This White Paper #227, How Higher Chilled Water Temperature Can Improve Data Center Cooling System Efficiency, would outline the various strategies and techniques that can be deployed to permit satisfactory cooling at higher temperatures, whilst discussing the trade-offs that must be considered at each stage, comparing the overall effect of such strategies on two data centers operating in vastly different climates. 

Schneider Electric’s study found that an increased capital expenditure of 13% in both cases resulted in energy savings of between 41% and 64%, with improvements in TCO between 12% and 16% over a three-year period.

Another inherent benefit of reducing the amount of energy expended on cooling would be the improvement in a data center’s PUE (Power Usage Effectiveness) rating. As this is calculated by dividing the total amount of power consumed by a data center by the power consumed by its IT equipment alone, any reduction in energy expended on cooling would naturally reduce the PUE figure.

The Schneider Electric study found that PUE for the two data centers examined was reduced by 14% in the case of Miami and 16% in the case of Frankfurt.

About the Authors 

  • Paul Lin – is a Senior Research Analyst at Schneider Electric’s Data Center Science Center. He is responsible for data center design and operation research and consults with clients on risk assessment and design practices to optimize the availability and efficiency of their data center environments. Mr. Lin holds a master’s degree in mechanical engineering from Jilin University.
  • Victor Avelar – is the Director and Senior Research Analyst at Schneider Electric’s Data Center Science Center. He is responsible for data center design and operations research and consults with clients on risk assessment and design practices to optimize the availability and efficiency of their data center environments. Avelar holds a bachelor’s degree in mechanical engineering from Rensselaer Polytechnic Institute and an MBA from Babson College.
  • John Bean Jr. – is the Director of Innovation for Racks and Cooling Solutions at Schneider Electric. Previously he was World Wide Engineering Manager for Cooling Solutions at Schneider Electric, developing several new product platforms and establishing engineering and laboratory facilities in both the USA and Denmark. Before joining APC, Mr. Bean was Engineering Manager for other companies involved in the development and manufacture of mission-critical cooling solutions.