IT Equipment: Selection
Goal: The IT equipment is the reason for the facility. Increasingly, there are reasonable opportunities to increase the efficiency of IT equipment, reducing the need for mechanical infrastructure and ongoing energy use directly at the load level through the selection of IT equipment.
- Objective 1: Specify efficient server equipment. Reducing the energy use of the load, IT equipment, directly is possible and has multiple cost savings — lower total infrastructure requirements, lower cooling loads, lower electricity consumption, smaller UPS, etc.
- Strategies:
- Specify High Efficiency Power Supplies. Server power supplies can be made significantly more efficient than currently offered. Specify power supplies that have a minimum efficiency equal to or greater than the minimum recommended power supply efficiency guidelines put forth by the industry group Server System Infrastructure (SSI) Initiative. See the 80Plus Website.
More > Power Supplies [See Chapter 8 of the Design Guidelines Sourcebook] - Consider Equipment Power Consumption in Specifications. Develop internal procedures to encourage the acquisition of the most energy efficient equipment that will meet the application requirements. Lower power consumption chips, idle mode setbacks and other features can vary the power efficiency of equivalent equipment. Reference: new chips from Sun [download]. See the 80Plus Website.
More > Power Supplies [See Chapter 8 of the Design Guidelines Sourcebook]
- Specify High Efficiency Power Supplies. Server power supplies can be made significantly more efficient than currently offered. Specify power supplies that have a minimum efficiency equal to or greater than the minimum recommended power supply efficiency guidelines put forth by the industry group Server System Infrastructure (SSI) Initiative. See the 80Plus Website.
- Metric: Power Supply Efficiency. Power supplies in IT equipment should be better than 80% efficient from 20% through full load.
- Strategies:
- Objective 2: Use cooled equipment racks. Incorporating waste heat rejection directly into the IT equipment racks can allow for it to be collected and rejected very efficiently.
- Strategies:
- Use Equipment Racks with Integral Coil. Transferring IT equipment waste heat to a cooling water loop directly at the rack allows for the complete elimination of heat recirculation. The heat is captured prior to mixing with the room air at a higher air temperature. This allows a correspondingly higher cooling water temperature to be used in the cool, allowing significant plant efficiency opportunities. Since IT equipment heat is removed prior to it being mixed into the room air, a much smaller room conditioning system can be used — a standard office system with the addition of humidity control and enough capacity to cool racks that are open for servicing can be used.
More > Direct Liquid Cooling [See Chapter 5 of the Design Guidelines Sourcebook] - Consider Direct Liquid Cooling. Direct liquid cooling options range from the mature technology of providing water passages through chip heatsinks to new approaches under development, ranging from using heatpipes to conduct heat from a chip to a liquid reservoir to spraying whole boards directly with an inert dielectric cooling fluid. Direct liquid cooling is far more efficient than using air cooling, which requires about 3,500 times the volume to remove the same quantity of heat. Where direct liquid cooling options are offered, they should be carefully considered for their significant fan power savings and synergy with medium temperature chilled water loops and waterside economizer free cooling. More info [download].
More > Direct Liquid Cooling [See Chapter 5 of the Design Guidelines Sourcebook]
- Use Equipment Racks with Integral Coil. Transferring IT equipment waste heat to a cooling water loop directly at the rack allows for the complete elimination of heat recirculation. The heat is captured prior to mixing with the room air at a higher air temperature. This allows a correspondingly higher cooling water temperature to be used in the cool, allowing significant plant efficiency opportunities. Since IT equipment heat is removed prior to it being mixed into the room air, a much smaller room conditioning system can be used — a standard office system with the addition of humidity control and enough capacity to cool racks that are open for servicing can be used.
- Metric: Watts cooling device / rack Watts cooled. The combine wattage of all fans (including small, in-rack fans) and pumps utilized by the liquid cooled rack to transfer heat to the chilled water loop divided by the actual watts of rack cooled should be less than 0.202 (0.71 watts per ton of delivered cooling).
- Strategies:
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