Basic Air Flow Management Tips

With summer here, we all think about warm days ahead and all the fun activities that go along with the season; but summer heat is NOT something we look forward to for our computers.

To protect computers, data centers should be well insulated with no windows to the outside to keep summer heat away from sensitive equipment.

Cooling is a large percent of the operating cost of running your data centers and to further save on costs of cooling, I have put together a list of basic best practices that can help maximize the cooling systems in your raised floor environment and help lower your operating costs.

 

  • Always use hot/cold aisle configuration, when possible, to maximize cooling from your systems. By not using this configuration, you will blow hot exhaust air from one row of servers into the next server row’s intake vents.
  • Cold Aisles should always be two tiles wide. Only place perforated tiles in these aisles.
  • Install brush grommets to keep the static pressure maximized under the raised floor and achieve optimum delivery of cold air to your cold aisles. By not using brushed grommets, you waste cool air in areas not requiring cooling which raises your operating costs and makes your cooling system less efficient.
  • When installing and removing power whips or communication cables, remove no more than six raised floor tiles at a time. Removing more than six tiles can cause a significant drop in static pressure under the raised floor and cause equipment to overheat.
  • Blank off unused server rack positions. Unblocked open racks can cause bypass air from the hot aisles to mix with cold aisle tempering the intake air to your servers.
  • If you have CRAC or CRAH units not in use or shut down for maintenance, place a Plexiglas cover over the top of the unit, above the filters, to prevent loss of static pressure from the back-flow under your pressurized raised floor.
  • Avoid creating air dam buildup of cables under the raised floor which will interfere with airflow. Run power and communication cables in the hot aisles. Never leave any communication/fiber optic wire spools under the raised floor; purchase them to the proper length. Cable build ups block air movement and also create a fire hazard.
  • Check the CFM output on each of your CRAC/CRAH units to make sure they are at factory specifications. If it is below the specifications, you are not getting the maximum cooling the unit is designed to deliver. It is also very important to know you are not exceeding the factory specifications because this can cause an over draw of amperage to the fan motors, which could shorten their life.
  • Create a good maintenance program to ensure your CRAC/CRAH filters are changed on a regular basis. Dirty air filters can reduce the output capacity of your A/C units and contaminate the under floor air plenum.
  • Never place perforated tiles closer than 6 feet (3 tiles) from of your A/C units. The air velocity coming from the unit can be so great that it will actually cause air to be sucked into the perforated tile, rather than blow out. This is not only ineffective for cooling servers but can temper the cold air under your pressurized raised floor.

Ken Koty

kkoty@pducables.com