White Paper

ManualsBrandsHP ManualsComputer AccessoriesModular Cooling System

Cooling strategies for IT equipment

Technology brief

Introduction ......................................................................................................................................... 2

Limits of traditional cooling practices ...................................................................................................... 2

Free cooling strategies.......................................................................................................................... 4

Air-side economization ..................................................................................................................... 5

Water-side economization ................................................................................................................ 6

Benefits and disadvantages of free air cooling .................................................................................... 6

Air containment strategies ..................................................................................................................... 6

Cold-aisle containment ...................................................................................................................... 7

Hot-aisle containment ....................................................................................................................... 8

Closed-loop cooling systems .................................................................................................................. 9

HP Modular Cooling System .............................................................................................................. 9

HP Performance-Optimized Datacenter ............................................................................................. 11

Choosing the best cooling strategy ...................................................................................................... 12

Cooling decisions based on facility characteristics ............................................................................. 12

Cooling decisions based on room layout .......................................................................................... 13

Cooling decisions based on server density/power per rack ................................................................ 13

Managing data center cooling ............................................................................................................ 14

Managing ITE cooling with HP Systems Insight Manager .................................................................... 14

Managing the data center environment with HP Environmental Edge .................................................... 15

Conclusion ........................................................................................................................................ 15

For more information .......................................................................................................................... 16

Call to action .................................................................................................................................... 16

Summary of content (16 pages)

PAGE 1
Cooling strategies for IT equipment Technology brief Introduction ......................................................................................................................................... 2 Limits of traditional cooling practices...................................................................................................... 2 Free cooling strategies..........................................................................................................................
PAGE 2
Introduction If you’re deploying the latest generation of information technology (IT) equipment or adding more servers to a crowded data center, conventional data center cooling methods and systems will likely be inadequate. The most effective cooling solution for any computing facility depends on the specific characteristics of the facility, equipment layout, and server density. This technology brief first explains limitations of traditional cooling practices.
PAGE 3
Server blade systems and 1U servers let you assemble high-density infrastructures; however, these systems create much more heat per square foot of floor space and more hot spots. In instances like this, the open-area approach cannot keep up with the demand for cool air. Figure 2 compares two examples of server loading for a 42U rack. In Figure 2A, our rack contains 20 HP ProLiant DL380 G5 servers, each consuming approximately 424 watts for a total rack consumption of 8.47 kW.
PAGE 4
The increasing heat loads created by the latest server systems require more aggressive cooling strategies than the traditional open-area approach. Such strategies include the following: • Free cooling • Air containment • Closed-loop cooling Figure 3 identifies cooling strategies and implementations based on kilowatts per rack and on the server density per rack.
PAGE 5
Air-side economization Air-side economization uses a system of supply and return fans, filters, and dampers that maintain positive air pressure with respect to the IT equipment exhaust, and positive data center air pressure with respect to the outside. Air-side economization may also include supplemental cooling coils that you can switch in and out of circuit as needed for changes in climate. You can implement air-side economization as either a direct or indirect system.
PAGE 6
Water-side economization Water-side economization uses a cooling tower as either the primary or supplementary means of cooling the chilled water supply for an air conditioning system. In a typical data center application (Figure 5), a cooling tower cools water in the condenser circuit, which in turn cools the chilled water in a common heat exchanger. The purpose of the external heat exchanger is to take the load off the CRAH, which can consume significant energy if the cooling load is high.
PAGE 7
Cold-aisle containment In a cold-aisle containment system, two ITE rows face front-to-front, with the cold air coming up through vented floor tiles of the common aisle. Cold air is isolated from the rest of the room air with curtains and/or Plexiglas panels (Figure 6). This ensures that only cold air is drawn into the ITE racks. The warm exhaust air exits the rear of the racks and is collected conventionally by the CRAHs.
PAGE 8
Hot-aisle containment In a hot-aisle containment system, two ITE rows are positioned back-to-back. As illustrated in Figure 7, the warm air exhausts into a common aisle area that is isolated from the rest of the room by doors and vertical ducts. The warm exhaust air is directed up to a dropped ceiling plenum and back to the CRAH.
PAGE 9
Closed-loop cooling systems Closed-loop systems are designed specifically for cooling IT equipment. They are the best solution for high-density systems consuming many kilowatts of power. These systems have separate cool air distribution and warm air return paths that are isolated from the open room air. Closed-loop systems typically use heat exchangers that use chilled water for removing heat created by IT equipment (Figure 9).
PAGE 10
The HP MCS G2 supports the front-to-back cooling principle. It evenly distributes cold supply air at the front of each rack so components receive adequate supply air regardless of their position or density. Warm exhaust air collects in the rear of the rack. Fans direct it into the heat exchanger where it is cooled and re-circulated to the front of the rack. Condensation flows through a discharge tube to a tray integrated in the base assembly.
PAGE 11
HP MCS cooling requirements The HP MCS G2 adds minimal heat to the room because most of the heat generated inside the cabinet is removed through the chilled water loop. It exchanges a small amount of air with the room during normal operation. Depending on the room temperature, rack power consumption, and system configuration, up to 10 percent of the total internal heat load may pass into the room.
PAGE 12
The HP POD supports HP or any third-party IT equipment that conforms to 19-inch industry-standard mounting and front-to-back air flow. The only requirements at the location of installation are as follows: • Utility power: 2 x 480 V/3-phase delta, 400 A, 50-60 Hz • Communications • Chilled water: Flow rate: HP POD 2000c; 120 gpm HP POD 4000c; 240 gpm Maximum inlet temperature: 55º F – 75º F (12º C – 24º C) HP PODs can be installed inside existing buildings or outdoors.
PAGE 13
Cooling decisions based on room layout If facility characteristics allow several cooling options, the rack layout can suggest which cooling strategy should be used. Figure 12 compares two data center layouts, each with four rows of racks. Figure 12A shows two pairs of rows with each pair facing each other to create two cold aisles and three hot aisles. This layout lends itself to a cold-aisle cooling strategy since only two rows require containment.
PAGE 14
Managing data center cooling High-density data centers require close monitoring and management to achieve and maintain efficient and economical cooling. We offer two solutions, HP Systems Insight Manager and HP Environmental Edge, to manage and monitor cooling status. These tools can be used separately or together as a comprehensive management solution.
PAGE 15
Managing the data center environment with HP Environmental Edge HP Environmental Edge technology helps you monitor two critical areas of the data center: power and cooling. Using sensors with wireless radio modules and software running on an Environmental Edge server, HP Environmental Edge measures, compiles, and analyzes data center power and cooling data.
PAGE 16
For more information For additional information, refer to the resources listed below. Resource description Web address HP Rack and Rack Options http://h18004.www1.hp.com/products/servers/proliantstora ge/racks/index.html HP 10000 G2 Rack Air Duct Kit http://h18004.www1.hp.com/products/servers/proliantstora ge/rack-options/rack-air-duct/index.html HP Modular Cooling System http://h10010.www1.hp.com/wwpc/us/en/sm/WF05a/34 47589-3447589-3446285-3446371-34619173657806.