Redundantly Cool

Redundantly Cool

We have about 10 minutes if we’re lucky…

That’s about how long it takes our mini server room to go from 72F degrees to 100F degrees. Just 10 minutes, but probably less. Usually the top of the racks are running a bit hotter, and shortly after 100F degrees room temp do we start to see a couple of the higher mounted servers stop responding. I’m not sure of a more clear picture I can provide for the need for cold air and it’s value for our daily operations.

I’ll say it again to try to emphasize the importance: 10 minutes without AC and the servers start coming down.

We generate a good bit of heat here, our internal server room design (server room isn’t connected to any outside walls) is great for physical security and damage prevention, but not the greatest for cold air routing options. Adding duct work isn’t an easy feat without a major remodel, and adding a PTAC or window unit wouldn’t help as it’d likely just dump uncomfortable hot air and into our office area.

Fortunately for server rooms (or buildings without ductwork options) they make a wonderful solution that doesn’t break the bank. Ductless mini-split units provide a solution for sending cold air to the places we need without an incredible amount of remodel cost. The units themselves are a bit pricier than you’d buy a window unit or PTAC for, or even a conventional central air unit, but have the added benefit of some great efficiency and the reliability to be operated in a 24×7 environment.

Technically Mini Splits aren’t much different from a window or wall mounted unit, only that the compressor is not attached to the unit directly, providing an easier solution to get multi-ton BTU equivalent units into specific hot areas.

A couple years back we installed a 1 ton Fujitsu backed up by building AC (you can see it in the picture to the right). This was a good solution at the time. The 1 ton unit would take care of the servers and if there was a failure or leak the 2 ton building AC would hopefully compensate and keep everything running cool. In our tests, this worked pretty darn well.

Fast forward a couple years, a few more servers, and 40 or 50 more hard drives in operation and we were running fairly low on cooling capability. A power outage on the building caused the temps to climb to 88F before leveling out so it was a clear indication an upgrade was necessary sooner rather than later.

The new unit is a 2.5ton Fujitsu, both server room units now run off generated power and the server room should be able to handle a few KW more energy usage before we’ll have to come up with another plan. A big thanks goes out to Keith and his guys at KNZ for all the help both in consultation and installation. Thanks guys, job well done.