Lesmerises was speaking in Las Vegas in March on the sidelines of Data Center World, an international conference and expo for data centre and IT infrastructure professionals. It draws on the experience of over 3,500 AFCOM members, the association for advancing data centre and IT infrastructure professionals, and is an important opportunity to demonstrate new products.

Quebec-based Carnot Refrigeration has been one of the most versatile OEMs in the HVAC&R industry when it comes to marketing transcritical CO2 refrigeration systems. Carnot’s greatest success has been as a provider of transcritical CO2 systems to Sobeys, Canada’s second largest food retailer. But Carnot has not stopped there, building transcritical units for industrial warehouses, ice rinks and data centres as well.

It was the data-centre market that Carnot’s founder, CEO and president, Marc-André Lesmerises, was targeting in March in a presentation at Data Center World in Las Vegas. A study by market research firm BSRIA predicts that, over the next five to 10 years, the use of traditional computer room air conditioning (CRAC) units will drop as end users opt for other technologies like free cooling, liquid cooling and chilled water cooling, opening up opportunities for CO2 systems.

Problem with R22

In September 2014, Bell Canada, the country’s largest telecommunications provider, became one of the first companies to install a CO2 transcritical cooling system for data centres – Carnot’s Aquilon unit – at its Ottawa facility. Bell Canada initially approached Lesmerises after finding out what he was able to accomplish with Sobeys. “They said, ‘we have the same problem with 3,000 sites that have CRAC units with R22 and we need to replace the refrigerant or the unit’,” he said at Data Center World.

Bell Canada’s 105kW system, which features Carnot’s patented Rain Cycle free-cooling technology, replaced an R22 system. The UL-approved Aquilon system costs about the same as HFC CRAC units, functions 95% of the time in free cooling mode and has cut energy use by 70%. Bell Canada is now running the Aquilon system at two sites, as is Rogers Communications, the second largest telecommunications company in Canada. “Both are impressed with the efficiency of the unit,” said Lesmerises.

Easy retrofits

CO2’s advantageous thermodynamic properties make it a useful refrigerant for data centres, Lesmerises told the Las Vegas audience. For example, its high volumetric capacity results in smaller piping sizes. This compensates for the higher price of stainless steel piping and also enables “a more compact system or more capacity for the same size,” he said.

A data centre can take advantage of the ability of the CO2 system to offer more capacity for the same size if it needs more cooling capacity in the same space. “You can take out the existing unit, put ours in, and you have more capacity for the same footprint,” said Lesmerises. “We can easily retrofit an existing data centre.”

In addition, a CO2 system can achieve free cooling with just 1°F of temperature difference (TD) between the refrigerant and air in the evaporator, compared with a much greater TD for synthetic refrigerants like R134a. Also, the CO2 CRAC unit, unlike HFC units, uses a fan rather than a pump to save energy. Heat recovery, which is not always easy to do in a data centre, is possible with the CO2 system. “We have a system that can generate megawatts of heat recovery,” said Lesmerises.

To calm any end user concerns about technicians’ familiarity with CO2 systems, Carnot maintains a 24-hour remote communication help desk at its headquarters to assist technicians on site.

This article first appeared in Issue 15 of Accelerate America. To read the full version, please click here.

Author r744