Cooling your datacenter / Server Room Temperature Control

Managing the cooling in your datacenter or server room can be quite a tricky subject. However, there are many different guidelines to follow that will help explain exactly what cooling solutions will work best for your datacenter. There are many different types of cooling that may work in different situations.

 

What is a BTU?
A BTU stands for British Thermal Unit. A BTU is the amount of energy required to raise the temperature of a pound of water one degree Fahrenheit. Since you are not concerned about heating a room, but yet cooling it, the BTU measure you will be concerned with is an Air Conditioner’s rating to control a certain amount of BTUs.

How Many BTU do I need?
This is not a very simple question, however there are several factors that contribute to how much cooling power a specific room or datacenter needs. The big factors are space of the room, equipment, lighting, and people. To calculate an estimated total requirement for cooling follow the steps that follow.

The size of the room has a lot to do with how many BTUs you will need to employ to cool down your server room or datacenter. Use this equation to determine how big of a factor the size of your server room is. This assumes you have 8 ft ceilings and the average amount of insulation of a datacenter. Remember that the length and width is in meters and not feet.
Length X Width X 330 = BTU from space.

Another large factor to consider while cooling your datacenter is the equipment. As equipment gets faster, more powerful, larger storage, etc. it also gets hotter. Switches, routers, SANs, and severs all generate large amounts of heat. Hard drives and processors both generate large amounts of heat. Luckily, units that generate a lot of heat are also the ones that consume a lot of power. This makes the calculation significantly easier since you can use the wattage to calculate the power consumption of equipment. It is best to judge from the total consumption rating on your server, SAN, switch, or router instead of using actual consumption. Otherwise, during peak times the datacenter runs the risk of overheating.
Total Wattage X 3.5 = BTU from equipment.

 

If your server room or datacenter is well lit, it is also important to take the heat that is generated from these lights into consideration. Lighting generates a noticeably higher amount of heat per watt of power consumption. Use this equation to determine total BTU output from lighting.
Wattage X 4.25 = BTU from lighting.

While many datacenters and server rooms rarely see occupants on the server floor, it can be important to take note of if there is support staff involved with the servers. Calculate from the maximum expected number of occupants that will be in the room at any one time for an extended period of time.
Occupants x 400 = BTU from people.
To calculate the total BTU of your datacenter or server room, add all these calculations together. You may want to consider other sources of heat that might be unique to your datacenter.

Which Cooling Solution Should I Use?
This depends on the BTU that you calculated above. It also depends on weather you have a small server room, or a large datacenter. If you have a small server room, you might want to either get a window unit or a NetworkAir PA unit from APC. If you have a much larger need, you will have to look into higher-grade industrial strength air conditioners. These industrial grade air conditioners will probably not measure their cooling capacity in BTU but in TONS. One Ton of cooling power is the same as 12,000 BTU.

Now you can calculate your total BTU and consider which unit to chose for your datacenter or server room. It is important to consider future expansion, and be prepared for it. Buying a cooling unit for the current equipment and having plans to put in several more racks full of servers would not be a good idea. It would probably require buying a whole new cooling unit, or some alternative small cooling unit. It is also important to consult with an expert before making a purchase on anything that is mission critical. Just remember to take everything into account while planning your next server room or datacenter.

by Tyler Weaver