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Appendix A
Green IT Checklist and Recommendations 221

cooling for that cabinet. This is especially useful where a hot side of a
cabinet faces a cold side of an adjacent cabinet.
✓ If you need enclosures for additional cooling, you still should have two
floortiles-width for servicing. One is tight and three is wasteful.
✓ Do an assessment that looks at both temperature and air flow. IBM has
advanced tools and models to assist this baselining of what the cooling
profile is.
✓ Use free cooling. Outside air can substantially reduce energy required by
computer room air conditioners. Data center site selection will enable
more days of free cooling when the climate has big difference between
day and night temperatures. Colorado is an example of an excellent
climate to exploit free cooling.
✓ Enable Active Energy Management (IBM Power Director Active Energy
Management with Tivoli). If you do not measure, you miss understand-
ing easy opportunities to improve. Measuring enables new charging
methodologies that include energy consumption.
✓ Charge for usage and have a surcharge for equipment at peak demand (or
ptg
a reduced rate at off hours).
✓ Larger than code copper distribution (wiring for data center).
✓ Whereever possible, eliminate conversion losses. This includes using high-
voltage power, as well as rotary UPS.
✓ Plan for use of 480V (or 600V) to equipment. The mainframe uses these
today.
✓ Enable dynamic provisioning of server and storage resources. This can
reduce, as well as turn off, the number of servers drawing power.
✓ Modeling suggests at least 24 inches of unobstructed raised floor.
Optimize air flow, putting less stress on CRACs. Fewer than 24 inches
will need higher velocities of air.
✓ Plan for water. It will be used on high-end equipment to reduce energy
requirements and hot spots on the raised floor.
✓ Capture rain water for onsite storage of water.
✓ Putting water closer to heat loads can minimize the need for more air
conditioning.
✓ Control hot air rising. How? Ceiling return of hot air, row air curtains, or
use card board or plastic if you want to really go cheap. Block for recircu-
lation, but make sure you can use sprinklers. Dividers to the ceiling can
prevent hot air from escaping into cold aisles.