The Cooling Effect

Today, there is a need of coolingtechnologies that can efficientlytackle the datacenter heat and ensurethat the IT equipment gets the right coolingenvironment. Next-generation computinginfrastructure and high-density enclosuresolutions are some of the technologies thatare widely used to reduce datacenter heat.Along with technology, various othertechniques help in dissipating heat andconserving energy, one example being thewater-based cooling in racks instead of genericdatacenter cooling which is monitored throughsensors. Shailendra Badoni, COO of DatacraftIndia, said, “Modular cooling system attachesto a server rack and uses chilled water todistribute cool air across the front of the rack.Effective cooling allows more servers to beinserted into racks, which often have emptyslots to avoid heat buildup.”

THE PUSH FACTORS

The frequent change in IT isleading to high-density, compactly-designed equipment, whichgenerate twice the heat of olderversions and performs almost10 times more efficiently and iscost-effective, in turn, leading tothe need for developing newdesigns in cooling.Some of the factors that haveled to the development of thesecooling technologies include theneed to optimize power costs byreducing energy consumption dueto datacenter cooling, supporthigher power density equipment,pressure to reduce overall energyconsumption and tackle diversechallenges in different environ-ments. The other significant factorsare the continued demand bybusinesses to reduce operationalcosts, increase efficiency, and help the businessgain a competitive edge. With the newgeneration of energy-hungry computer serversand equipment, issues of optimizing rack-levelperformance in a minimum amount of spacehave become a major challenge for datacenters.“Today, the reason for a high cost of operationof a datacenter is the high power bills, out ofwhich almost 55 to 60 percent is on accountof the cooling systems. The focus of thesesolutions is to help companies reduce theiropex and still eliminate the hot spots that areassociated with air distribution. This also helpsorganizations in reducing their carbonfootprint,” added Manish Bhatnagar, CTO, APWPresident Systems.

Bhatnagar further added that another majorfactor is that it helps organizations in reducingthe datacenter space requirement by helpingthem populate more equipment in the racks.Other factors include addressing theheterogeneous cooling profile of heat loadin datacenter IT racks, addressing thecooling requirement of high-density IThardware like Blades and mainframes andmaking datacenter cooling scalable andmodular.

SOME SIGNIFICANT TECHNOLOGIES

In a server room or datacenter, the cooling isabout effective distribution of cold air withcontrolled humidity and efficient removal ofhot air. Specifically designed for datacenters,CRAC (Computer Room Air Conditioning) unitsprovide benefits such as monitoring, reliabilityand redundancy and capacity tailored to thehigh Sensible Heat Ratio (SHR) loads found indatacenters.

CRAC maintenance is critical to avoidFor more stories on green IT go to www.dqchannels.comGREENNOOKdowntime in a computer room, server roomor datacenter environment as proper CRACmaintenance reduces overall cost ofoperation in these environments. Also,companies are able to maintain thesesystems at peak performance and, ultimately,reduce the cost of ownership in terms ofreplacement and day-to-day use.

Then there are 'row-based' coolingsolutions, that are typically deployed in adatacenter site that lacks sufficient height,where future IT growth cannot be forecastedand high-density racks are about to bedeployed. Row-based cooling techniquesare used to supplement cooling in raisedfloor scenarios that face limitation incooling, thereby increasing the coolingcapacities. Row-based cooling architectureshave emerged as the preferred solutionfor scalable and modulardatacenters.

Furthermore, in a 'rack-oriented' architecture, the CRACunits are associated with a rackand are assumed to be dedicatedto it for design purposes. TheCRAC units are directly mountedon or are within the IT racks. Therack-oriented architecture hasother unique characteristics inaddition to extreme densitycapability. It allows coolingcapacity and redundancy to betargeted to the actual needs ofspecific racks, for example,different power densities forBlade servers v/s communicationenclosures. And technologies likeRear Door Heat Exchanger (RDHx)have an added advantage thatthis is a non-invasive technologywherein the cooling can beaugmented without taking an ITdowntime. These doors can beconveniently mounted at the rearof the rack by using a transition frame.

“To improve the efficiency of a row-basedsystem either rack or row-based containmentsystems can be added. These self-containedhigh-density cooling systems are designedto be installed in a datacenter withoutimpacting any other racks or existing coolingsystems. Such systems are thermally 'roomneutral' and will dissipate hot air from ITequipment,” added Badoni.

ADDRESSING THE CONCERNS

These technologies bring down the PowerUsage Effectiveness (PUE) of datacenters-to provide the same amount of computepower that one requires for generating lesspower. This directly contributes to savingpower generation and secondly, reductionin air-conditioning also directly reducesgreenhouse gas emissions,” asserted Mahesh Trivedi, VP-Datacenter Infrastructure,Netmagic Solutions.

Moreover, using smart cooling technologiesreduces power consumption, therebydecreasing greenhouse gas emissions which arereleased due to power generation. Thesetechnologies have to be right sized for eachsituation in order to produce the maximumimpact on cost, power consumption, andcarbon footprints that leads to a decreasedcost of power. And having better control ofairflow and cooling equipment being placedwith better planning and closer to the heatsource helps in avoiding heat exchangehotspots within the datacenter.

According to Bhatnagar, the RDHx solutioncan support power densities of up to 35kWper rack, making it easier for customers toconsolidate equipment (that previouslyrequired multiple racks) into a smallerfootprint. It enables up to five times morecompute power to be placed in a given rack.Liquid cooling with RDHx is by far the mostcost-effective cooling technology. It consistentlyreduces cooling energy consumption by50 percent or more, cuts datacenter spacerequirement by 55 percent and offers completeRoI within a year. It also helps reducing carbondioxide emission.

A LOOK AT OTHER AREAS

There are companies that have implementedvarious power-saving measures in theirdatacenters, including energy-efficient computer room design, cube technology,passive, IR-activated lighting in darkroomcomputer suites, hot and cold aisles andcogeneration.

Then there is indirect evaporativecooling system technology like Free AirCooling technologies (air side economizersand water side economizers), water-cooledDX Precision air-conditioning systems, andair management technologies like air blockcurtains, hot/cold air containments, powerVAV fans, etc, that help in tacklingdatacenter heat in a effective way. Asdatacenters embrace racks of servers andclosely packed blade servers, whichgenerate more heat per square foot thanindividual servers, liquids may be the onlyway to keep up. The emerging liquid-cooling technologies are probably a way oftackling heat effectively. They range fromwater jackets that surround servers to themore radical approach of spraying liquidson a server's electronic components.

The technologies of the future willrequire cooling right on the server micro-chips. While these technologies are availa-ble even today, they will come to com-mercial use once the server manufacturersshift their focus to chip-based cooling usingwater to accommodate loads up to 50kWin the next few years.

NIVEDAN PRAKASH
(nivedanp@cybermedia.co.in)