While everyone is trying to save money by controlling energy usage at data centers (the topic has even hit the pages of the New York Times in recent days) what do we do with all the older data centers?  How can we increase efficiency in these sites?

One answer is to control the cold air.  While controlling the warm air is also important, it does what it does naturally — rise.  Cold air, on the other hand, needs to be delivered to the proper location for it to do its job.

Many of the older data centers were designed with under-raised-floor-cold-air delivery.  The rooms are lined with CRAC units that draw warm air from the overhead area and deliver cold air under the floor to be distributed through perforated tiles.

In my experience, you contain the vital resource to the maximum extent possible to minimize losses and conserve it.  So it has always seemed strange to me that designers and engineers have historically chosen to contain the warm air when the vital resource is the cold air.  I would allow the warm air to either escape or have the maximum opportunity to lose some of its energy to the environment so as to work with physics and not against it.

So continuing in this line of thought, why not channel the cold air directly into the cabinets of the servers?  Close off all of the perforated tiles (remove them) and cut holes with floor registers in them within the server cabinets.  Floor registers are cheap.  You can find them at your local hardware store.  Put the front doors back on the cabinets and you have a natural front channel for the cold air to rise within.  The focus then becomes correcting leaks from the air space below the floor and adjusting airflow into the cabinet for the heat load that’s present.  (Notice that with these registers you can actually adjust the flow to what you need versus some arbitrary amount.)  You can mount stick-on thermometers to adjust the air to the top server to a nice 75^oF or so.  You don’t even need to go overboard on the cooling.  With this solution, you will also have to “blank” the non-used positions in your racks.

That’s one thought on how to possibly save money in the older data centers.  If you have ideas around how to make older data centers more efficient, please send them as comments and I’ll post them.