Drive towards zero carbon data centres raises interest in “naturals” 

By Janaina Topley Lira, Apr 17, 2012, 00:00 2 minute reading

The intense heat loads produced by computer blade servers require cooling to maintain optimal operating temperatures. Their large power consumption, combined with rising costs of energy and the drive to be green, are resulting in ever-greater demand for environmentally sound server-cooling solutions such as CO2 cooling. In addition, to help the industry become more energy efficient ASHRAE will soon update i

Cooling of data centres is estimated to have an annual electricity cost of $1.4 billion (€1 billion) in the United States and $3.6 billion (€2.7 billion) worldwide. To meet this challenge and protect the millions of dollars worth of data stored, data centre cooling infrastructure design has become a critical task. Different options are possible including the use of refrigerant cooling using CO2.
CO2 cooling of blade servers
Cooling represents a valuable opportunity for IT energy cost savings. Whilst in many instances implementing simple changes such as improving room sealing, and moving objects to avoid the obstruction of airflow, hybrid R744 cooling systems can save up to 30% in energy, whilst CO2 has seven times the cooling capacity of water. Moreover, the increased capacity can reduce pipe diametres by up to 50%.
Below are some examples of companies investing in CO2 cooling technology for data centres:
  • AEI engineers have tested a rack mounted cooling technology that uses fans to pull air through equipment cabinets and into contact with refrigerant fluid CO2 circulated trough a vertical coil.
  • TROX AITCS and Star Refrigeration have developed the CO2OLpac that circulates CO2 as a cooling fluid to CO2OLrac devices fitted to the rear of computer equipment cabinets. These fan-powered units draw rejected blade server heat across a heat exchanger. The High Density Cooling solution is now in use in several data centres, including Imperial College London.
  • Adavante3C has designed a tailored CO2 cooling solution for Data IV, a large Web hosting company. To meet Data IV’s requirements for increased thermal dissipation capacity (from 1500 W/m2 to 3000 W/m2), and also set high energy-efficiency requirements CO2 was chosen as a secondary refrigerant in a loop circulating between the chilled water network outside the data room and the ambient near the computer racks. 
Data centre cooling training
At the 2012 Mostra Covengno Expocomfort trade fair held in Milan at the end of March 2012, ASHRAE presented their guidelines on “Data Centre Energy Efficiency” and the upcoming “IT Equipment Environment – Thermal Guidelines Whitepaper”. According to ASHRAE key drivers for updating the guidelines include 
  • Expanding use of the allowable range
  • Expanding the limits o the allowable charge
  • Defining new classes with wider environmental envelopes
  • Educating users on reliability
In addition to ASHRAE’s guideline update several companies are also investing in data centre cooling training, with several courses also looking at CO2. For example, the TROX Academy provides information on the principles of CO2 as a secondary refrigerant in data centre cooling and dealer desk cooling using CO2. NBIZ provides a course on data centre cooling that looks at R744 refrigerant comparisons.


By Janaina Topley Lira

Apr 17, 2012, 00:00

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