Page 96 -

C C o o l i n g o o l i n g 67 67
C
C h a p t e r 4 : h a p t e r 4 :

You can take this number with you when you go air conditioning shopping. Small air
conditioning units have a cooling capacity of between 5000 and 10,000 BTUs. Larger units
use a measurement in tons of cooling. One ton of cooling is about the same as 12,000 BTUs.

Reducing Cooling Costs
If you’ve looked at your datacenter’s cooling bill (or have been afraid to), just know there
are some ways you can reduce costs. Also, if you find you need more cooling, it might be
wiser to deploy equipment that won’t chow down a lot of power. Table 4-2 shows how
much money different-sized datacenters can save in different parts of the world. It also
shows how much pollution can be cut when optimizing cooling.
In this section, we’ll talk about some equipment you can use that can save money and PART II
help supplement your environment.

Economizers
You can save a lot of money if you are able to put Mother Nature to work for you. In a lot of
the country, winter provides you with an opportunity to enhance your cooling system by
using the cold outside air to cool things down.
But it isn’t as simple as opening a window to accomplish this. To do so, you need to
employ what is called an economizer. There are two types: air-side economizers and water-
side economizers.
Air
An air-side economizer regulates the use of outside air for cooling a room or a building. It
employs sensors, ducts, and dampers to regulate the amount of cool air brought in.

Datacenter Size (Wattage) Small (1.5 MW) Medium (3.5 MW) Large (8 MW)
Cooling type Air Chilled water Chilled water
and air and air
Potential savings 40 percent 30 percent 20 percent
U.S. estimated annual cost $578,000 $1,012,000 $1,542,000
savings (@ $0.11/kWh)
Europe, Middle East, and $788,000 $1,380,000 $2,102,000
Africa estimated annual cost
savings (@ $0.15/kWh)
Asia, Pacific, and Japan $1,261,000 $2,207,000 $3,364,000
estimated annual cost
savings (@ $0.24/kWh)
Reduction in CO emissions 5000 8780 10,000
2
(metric tons per year)
TABLE 4-2 Cost Savings and Pollution Reduction Based on Cooling Optimization