Free air cooling aids Sainsbury’s energy reduction
The theory behind speaking at conferences is to see the new ideas discussed adopted in the marketplace. That certainly proved the case when Future-Tech’s Paul Elliott addressed the Data Centre Group of the British Computer Society.
Sitting in the audience was Peter Allwright, data centre manager for retail-giant, Sainsbury’s. Set with a target of reducing his centre’s energy output by 20% by 2012, Peter was struggling to find an efficient and cost effective way to make the saving. He was intrigued by Paul’s description of modern fresh air cooling and recognised it might provide a solution to Sainsbury’s needs at their Feltham Data Centre in west London.
The data centre operates with a supply air temperature in the floor void of between 15ºC and 17ºC. Thus any time that the outside air is below 15ºC it’is possible to cool the data centre using fan power only from the fresh air cooling system.
Sainsbury’s commissioned Future-Tech to design and install fresh air cooling for two (subsequently three) air handling units, fitting the new plant in a roof space above a suspended ceiling over the existing computer room. Adding a level of complexity to the initial planning, Future-Tech’s designs and project plan had to be approved by Sainsbury’s landlords. While this took time, the plan was approved without change.
The project involved the Future-Tech team installing an Air Handling Unit complete with an evaporative humidifier, filters and supply air motor and fan above the computer room in the attic space. Using structural calculations provided by structural engineering partner, Noak Bridge Consultants, the team built and installed a steel frame to support the air handling unit.
Future-Tech’s Frank Wilman explained why the evaporative humidifier made sense: “When it’s very cold outside, the relative humidity (RH) of the outside air is generally high but the absolute humidity - the total amount of moisture in the air - is very low. When this air is drawn into the data centre and warmed up, the RH drops. In extreme conditions it can fall outside the design parameters of the IT equipment.
“Traditionally humidifiers in data centres have been electrode boilers which use electricity to create steam and are therefore counter-productive from an energy saving standpoint. Evaporative humidifiers use the heat from the data centre to evaporate water and maintain the required RH. They not only use almost no power (there’s just a very small pump) but can actually contribute to the cooling effect during ‘mid-season’ conditions. For Sainsbury’s, with their focus on energy saving, this was definitely the right kit for the job. It’s worth noting too that evaporative humidifiers are both safe and hygienic and have no issues with carry-over of mineral particles or bacteria associated with spray humidifiers (the other alternative to electrode boilers).”
Challenge
“It was a challenge to retro-fit the kit into an existing building,” commented Future-Tech project manager, Paul Carter. “We had to bring in a crane and remove part of a wall to get the large elements in, but everything was planned and we handled the installation with no disruption to the data centre operation.”
“Future-Tech have proved to be extremely professional, flexible and adaptable in the way they’ve carried out the project and helped support our business needs,” Peter commented. “We operate 24-7 and didn’t have to switch a single system off while Future-Tech were on site. They took away any problems we might have faced and were proactive in managing every step of the process from the initial design to all the necessary follow-up to the installation.
“We managed to make life more challenging in between the design and implementation phases by adding an additional air handling unit. Initially we wanted the free air cooling to link into two units, but then decided to add a third. Frankly, Future-Tech didn’t bat an eyelid and ensured their solution met our needs.”
The solution
Fresh air is provided to the air handling unit via a louver and ductwork from the flat roof area. The air is then filtered and humidified before being introduced into the computer room ceiling void. Future-Tech has also installed an extract fan within the ductwork to extract return air from the computer room ceiling void and vent it into the atmosphere high above the existing condenser compound. And, to separate the supply and extract air, the team has installed barriers/plenums within the computer room ceiling void.
“We’ve been very impressed with Future-Tech,” Peter concluded. “The system went live in October 2009, and we’re already seeing significant benefits in terms of reducing our energy usage. In fact we’re so pleased with what’s been done to date that we’ve now commissioned Future-Tech for a second phase of work to introduce free air cooling across the whole computer room. They’re very sensitive to the needs of a busy data centre and do their utmost to ensure that our operation isn’t disrupted in any way by their activities. Working with Future-Tech has been a very positive experience.”
For more information contact Future-Tech on 0845 9000 127
Email: info@future-tech.co.uk
