Energy saving solutions for data centres

Jan. 29, 2013 - PRLog -- Energy saving through evaporative cooling and adiabatic humidification: integration and versatility

Data Centre applications have huge energy consumption. Thanks to its constant and relevant research in technologies for this application, CAREL offers high efficiency solutions through optimised and integrated control systems, capable of bringing significant energy savings for data centre cooling and consequently reducing environmental impact to data centres.

Data centre air conditioning is essential for the correct operation of information Technology equipment: processing and storage devices produce heat that needs to be removed in order to maintain optimum operating conditions.

Worldwide data centre power consumption is estimated to be 30GW, accounting for around 1.5% of the earth’s total electricity usage: as a result of this astonishing level of energy consumption, energy saving solutions is increasingly adopted.

Currently the most widely implemented technology solution involves the use of Computer Room Air Conditioners (CRAC) or Close Control Units (CCU), which cool and where necessary humidify the air in the data centre.

Continuous technological development in the sector and a constant focus on energy saving are reflected in the evolution of the air conditioning solutions adopted: from controlling air distribution to installing air conditioners near the heat sources, as well as using high efficiency equipment. Moreover, air handling units can be used to deliver outside air in free cooling mode, and where possible lowering temperatures even further using adiabatic humidifiers (evaporative cooling).

Evaporative cooling and adiabatic humidification; the data centre air conditioning solution with the highest energy efficiency and lowest environmental impact.

Direct free cooling + Direct Evaporative Cooling (DEC); the solution that optimises the use of outside air, lowering temperatures in summer through direct evaporative cooling (DEC) and controlling humidity in the winter using the same unit.

The system comprises of an Air handling Unit that introduces outside air in the summer for free cooling, plus DEC when the outside conditions allow. This ensures maximum efficiency, as the process does not involve intermediate heat exchange stages. The air is delivered into the cold aisles and distributed through grills or diffusers. The return fan then draws in air from the hot aisles.

A mixing damper controls the minimum supply temperature by modulating recirculation. In winter when the air is very dry inside, the DEC system can be used to ensure precise humidity control, with a power consumption of just 4W per litre of atomised water in comparison to 750W for traditional steam humidifiers used in CRAC units.

Indirect free cooling + Indirect Evaporative Cooling (IEC); the solution that maximises free cooling, employing indirect evaporative cooling without introducing outside air into the data centre due to problems such as pollutants, or humidity levels where DEC would not be feasible.

The system compromises of an Air handling unit that recirculates the air, cooling it via a heat recovery unit that exchanges heat with the outside air. This “secondary” air stream flows through the heat recovery unit without entering the data centre.

The evaporative cooler reduces the “secondary” air temperature, while at the same time increasing its humidity up to 95%, guaranteeing maximum cooling of the recirculated air. A cooling coil may deliver supplementary cooling capacity if needed, as well as guaranteeing redundancy.

In winter, a second water spray humidifier ensures precise supply humidity control, with a power consumption of just 4W per litre of atomised water. The air is delivered into the cold aisles and distributed through grills or diffusers. The return fan then draws in air from the hot aisles.

Indirect “water-side” free cooling + IEC; the solution for saving energy through evaporative cooling, however without modifying the air flows inside the data centre, using traditional air conditioning technology.

The system comprises perimeter CRAC, units that control supply or server room temperature and humidity. An evaporative cooling system (chillBooster), is installed on the dry cooler or the condenser, which reduces the outdoor air temp and cools the air intake of the cooler thus guaranteeing considerable energy saving by lowering the average refrigerant circuit condensing temperature.

In CRAC systems with water-side economizers, i.e. fitted with a water coil that can be combined with an outdoor dry cooler, chillBooster extends the period in which free cooling can be exploited, therefore considerably reducing the use of mechanical cooling (compressors).

CAREL has 40 years’ experience in data centres and has completed projects for datacentres in Europe and US and is partner of the most important players in the market worldwide.

For further information contact CAREL on 0208 391 3540 or visit their website http://www.careluk.co.uk

CAREL designs, produces and sales energy savings control solutions for the air conditioning and refrigeration sector. It has a sales network in over 70 countries, with plants in Italy, Brazil, China and the USA. The CAREL group has over 800 people, 13 subsidiaries and consolidated turnover of 151 million euros in 2011 (+13%), with an export percentage that exceeds 70%.

Innovation and technological advancement have followed every step in CAREL’s evolution. Proof of this lies in milestones such as having been the first in Europe to design and manufacture a microprocessor electronic controller for precision air-conditioners in computer rooms, in the early eighties. CAREL has always allocated an above-average percentage of sales to research, development and technological innovation. The personnel employed in the research and development of new products and market standards accounts for 18% of the total at a group level.