7 Things to Do with a Legacy Data Center in a Tough Economy
July 15, 2009

By Christopher Johnston, Syska Hennessy Group

Appeared in

Data center managers today are under pressure to reduce operating costs - and that's the easy part of the story. The hard part: They're supposed to accomplish this while maintaining availability and spending little or no money. They must focus on the low-hanging fruit.

Legacy data centers present the greatest challenge because of their older infrastructure and because they weren't designed to make changes on the fly. Luckily, there are proven strategies that can reduce operating costs without jeopardizing availability. Before considering those options, it's important to define the legacy data center that will benefit from those measures:

Here are seven things you can do with a data center to reduce costs while still meeting these requirements.

  1. Shut down UPS system redundancy. If you have a System + System (2N) UPS arrangement, and if you have a redundant module in each system, shut down the redundant modules. If you have a single UPS system with more than one redundant module, shut down all redundant modules except for one. You can turn on the redundant modules periodically - just long enough to charge the battery.
  2. Turn off all non-egress and emergency lights in computer rooms and support areas.
  3. Within reason, eliminate leaks in the access floor and between the access floor and the building structure so that the cooling air is introduced into the cold aisles and nowhere else. Cold air introduced where you don't need it is wasted.
  4. Install CRAC return extensions (top hats) or return duct extensions to stratify return air. The top of the top hats should be about 2 feet below the ceiling or structure above. This will increase CRAC return air temperature and increase operating efficiency and capacity.
  5. Turn off humidification and reheat in all CRACs except one or two in each computer room. Disable the relative humidity alarms in CRACs with humidification and reheat turned off. Set the CRACs with humidification and reheat to maintain relative humidity between 40 percent and 60 percent as recommended in the new ASHRAE TC9.9 guidelines. This will prevent CRACs from fighting each other.
  6. Move the control thermostat in each CRAC from the return air stream into the leaving air stream. This will provide better temperature control.
  7. Gradually increase CRACs, leaving air temperatures so that cold aisle temperatures are between 64.4 degrees F. and 80.6 degrees F. as recommended in the new ASHRAE TC9.9 guidelines. Remember: The higher the temperature, the lower the energy consumption.

Accomplish these seven things, and you should decrease your energy consumption.

Christopher M. Johnston is national critical facilities chief engineer at New York City-based Syska Hennessy Group.