Q&A: Server Closet Cooling
A question was asked on LinkedIn Answers regarding small server room cooling. The “server closet” in question is sub 300 sq ft and has issues with external temperatures dropping below the temperature threshold for current in-place wall unit cooling systems to handle.
The requester stipulated “reasonable cost” solutions.
Again, please remember, this is for a “server closet” solution.
What’s your budget look like? And what’s the heat load of the equipment in the room? Since you are using a wall unit, I am assuming your heat load is quite low. (Although there are some quite high-capacity wall units out there!)
APC has sealed cabinets that improve air-flow, perform some amount of humidity control, and remove heat very nicely. APC may be out of the question due to cost.
Another alternative is the “Robby The Robot” style spot cooling/ducted portable units. I’ve used these in mobile applications, emergency deployments, and data closets — they work well, while not as efficient as their wall/window mounted counterparts. Since these units actually sit inside the room, with hot air exhausted through a hose outside (through a vent, door, or window for example) there is little risk of condensation freezing during winter months. Your condensation bucket will have to be manually removed occasionally (such as in high-humidity environments) or you can plumb the unit to drain outside. These are fairly inexpensive and frequently used for small spaces.
When purchasing a new cooling unit, you may want to measure your heat load to calculate the size of air handling unit you will need, and to optimize power usage, as over or under powered cooling units use more power than an appropriately sized unit due to the amount of switching on and off and run times.
Whether you have a big server room or a little one, cooling is just as important. Small rooms tend to have their own issues such as ventilation and air circulation with little space for trapped heat to go (up or otherwise!) For a little more cash, you can get a variable speed unit which could help to circulate the air while not cooling, and cool at a lower volume for minor temperature changes thus distributing the heat more evenly around the room; this is especially important when considering small server rooms.
If you have any questions about my suggestions, feel free to shoot me an email.
Links provided as references are:
APC Rack Cooling Solutions
Portable AC Images
Calculating Heat Load
Please note: LinkedIn responses are limited in character sizes, so brevity is required.
It should also be noted (as it was, by another contributor) that wall mount units typically have a cut-out [lockout] that triggers when outside temperatures fall below a certain range to save power and preserve the unit. While modifying the lockout is certainly a cheaper alternative, I don’t recommend messing with the internals of any cooling system in such a way. Not only does it violate the warranty, but it’s also very dangerous (unless you’re a qualified A/C repair person, or electrician.)
Cheers!
