Smart air-cooling for Smart-IT

March 13, 2015

This paper introduces an effective cooling strategy to work in unison with today’s Converged Infrastructure, offering: 

  • Streamlined deployment—Critical cooling deployed in days, not weeks… complementing the IT deployment
  • Lower datacentre costs—lowering pro-rata energy costs (OPEX) with optimised supply-air delivery, and reduced infrastructure cost (CAPEX) with minor in-floor modification… not new specialised capital plant.
  • Availability for critical applications—Utilising existing facility cooling infrastructure resilience & integral fail-safe operation.

Converged infrastructure takes compute, network and storage components and integrates them into a single, cohesive pool that can be engineered, manufactured and supported by the vendor as a unified system. But who balances the environmental effects from this next generation IT equipment?

With frequent claims such as reducing the IT footprint, cost saving benefits, and increased compute density and storage utilisation, converged infrastructure is certainly not undersold. Whilst overall power may be reduced within the IT function compared to its legacy solutions, most significantly the heat generated from the condensed footprint means potentially delivering hot spots into the datacentre. Additional room cooling capacity may need to be introduced due to the spot cooling requirements, but more importantly the higher density footprint may require significantly increased “spot” air volume than the datacentre was originally designed to deliver.

Datacentres typically as young as five years old may have been designed to facilitate IT racks with a capacity of 2-3kw.

With the more recent adoption of Converged IT Infrastructure from 2010 onwards, spot rack load can be found to be between 5kw and 20kw.

1

Dynamic loads present a further dilemma with manual controlled cooling systems sized to facilitate only worst case cooling needs.  So, when servers idle, or replication is dormant, over provisioned air volume is often wasted causing not only inefficiencies but spot overcooling… a new set of problems.

Introducing dampers can be an effective solution to manage air delivery; maintaining floor pressure to support additional IT equipment load, balancing volumetric air supply requirements to demand from IT equipment. Innovative multiple zone dampers introduce further benefit, cooling from top to the bottom of the rack when demand for cooling is called upon. This proves particularly useful when partially filled equipment racks are deployed.

23

For example, if equipment is only installed in zone 1 of the rack, zone 2, 3 & 4 dampers can be shut to prevent wasted air volume, preserving floor pressure, and restricting potential bypass. These can be easily opened when equipment is installed at a later date.

When the dampers are automated, air volume can be managed dynamically by temperature demand at the front of the rack. Combined with floor plenum pressure control to local CRAC (Computer Room Air Conditioning) units, this provides effective energy preservation and also a means to maintain floor pressure integrity supporting the balance of IT equipment deployed in other areas of the room.

Installed in conjunction with directional air diffusers, an improved Capture index (compared to traditional grilles) can facilitate an increased cooling capacity to rack with comparable supply air volume.

 11

This provides the ideal platform to support  today’s Converged Infrastructure. When compute & effective cooling demand is low, automated dampers preserve supply air by closing the floor-grille aperture. Locally positioned temperature sensors at the front of IT rack proportionally open and close the damper with respect to the temperature set points required.

Frequently considered as a headache for Facility & Operations Managers in the datacentre, future change requests from their IT Department need not cause too larger concern anymore.

With a raised access floor, and recognised cooling capacity available from the existing perimeter CRACs, the DirectAire grille and SmartAire MZ damper configuration can be easily adapted to facilitate your next generation IT needs. It can also be relocated at a later date within hours, not days or weeks.

In combination with Datacentre Best Practices, airflow effectiveness is considerably improved with directional floor grilles and has been proven as an effective solution to the critical cooling needs of today’s Converged Infrastructure.

12

Thermal Images taken for proof of concept test with Directional Air Grille.