Data Center Energy Efficiency Measures to Improve PUE

The following list represents the key energy efficiency measures and major energy saving concepts to be employed to improve PUE:

  1. Air side economizer: the rooftop air handling units are equipped with the ability to utilize 100% fresh air to provide the cooling for the building, allowing the chiller plant to be turned off or operated at substantially less capacity, saving energy consumption.
  2. Hot aisle/cold aisle containment: by providing physical separation between the server inlets and outlets, re-circulation of hot air to the server inlets is minimized. This allows the supply air temperature of the cooling system to be raised, allowing the cooling plant to operate in a more efficient manner. The elevated supply air temperature also allows for more air side economizer operation where the cooling plant can be turned off (I.E. there are more hours where the outside air temperatures are cool enough to cool the data center space).
  3. Variable flow pumping systems for chilled water and condenser water. Variable flow fans for cooling tower and air handling systems. Variable flow technology allows the cooling systems to track directly with the building load requirements, without over cooling. The technology also allows the systems to optimize their performance to reduce energy consumption (I.E. operate at the optimum energy efficiency point for all load conditions).
  4. Redundant chillers, towers, and air handlers (required for data center reliability) will be operated simultaneously at a reduced speed. By operating systems at reduced capacity, a higher efficiency is obtained. For example, in air handlers, each air handler will move less air (net total air moved is unchanged) and thus the pressure drop through coils and filters is less and energy is saved. It should be noted that when pressure drop is cut in half, energy consumption is cut nearly by one eighth, so even slight reductions in pressure drop result in major energy savings, particularly in a 7×24 operation facility.
  5. Separate air conditioning systems for the office spaces. Although initial cost of the office AC systems is slightly higher, the two separate systems (office vs data center) can optimize their operation to closely match the demands of each space. If the office were connected to the data center chilled water system, the chilled water temperature would need to be lower than if only serving the data center and thus a higher amount of energy would be consumed.
  6. Premium efficiency motors.
  7. Highest efficiency transformer. Static losses through transformers throughout the facility will be minimized by procuring high efficiency transformers.
  8. Dynamic lighting control system to maintain office and data center spaces dark unless occupied.
  9. Photovoltaic panels in a project can offset a portion of the facility electrical demand. Additional structural work is required to support PV panels, utilities limit production per parcel to 1MW, but installation of non-regulated generation equipment reduces OP/EX costs.

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