Opt for high precision cooling
It is important to realise that only 30% of energy used in a data centre is expended on the actual IT equipment and storage units. The rest of the energy is required to power an array of other devices such as UPS systems, lighting, humidifiers/dehumidifiers, computer room air conditioning (CRAC) units, units for electricity distribution, and, not least, cooling. Once the energy required just to cool the data centre reaches 33% of the total energy bill, you’ll realise that cooling has to be efficient and a high-precision system.
Harness the energy benefits of free cooling!
Across much of Europe, free cooling, i.e. cold outdoor air used for cooling, makes a substantial contribution to the cooling efficiency of data centres. A distinction is made between direct and indirect free cooling. With direct free cooling, outdoor air is essentially blown in to eliminate heat generated by the computer equipment. This is ideal for centres with high air turnover. The advantage of this is its efficiency; the drawback being that you end up with less control over air quality and humidity. With indirect free cooling, the outdoor air cools a heat transfer medium, which then in turn cools the computer equipment. This provides far better control of air quality and humidity, and greater stability too. The drawback is that indirect free cooling is less efficient, as the disparity between the two temperatures in the transfer medium results in energy loss.
Data centre energy consumption can be reduced by up to 40%
The indirect free cooling can be utilised by means of two different technical solutions. For large data centres, the best option is external cooling with free cooling for the cooling water, which is a versatile and highly efficient solution for achieving a 30-40% reduction in annual energy consumption. By using electronically commutated (EC) fan motors, maximisation of energy performance is achievable even for partial loads.
For smaller-scale data centres and other premises that lack the space for large external coolers, the alternative is a system with direct expansion of the cooling water. This minimises compressor operation, reducing operating costs.
Improved fan control for energy-efficiency improvements
EC fans are the state-of-the-art option for data centre ventilation. These brush-free fans are electronically commutated and feature 3-D fan blades made of composite material. This means reduced noise and energy consumption, but also auto-adaptation in response to altered thermal loads, air volumes and static pressure.
With automatic fan optimisation, only the air volume required by the IT equipment is distributed. If the data centre is only partially filled with IT equipment, this can be compensated for with perforated flooring to enable the air volume to be down-adjusted and air flow rate to be reduced.
Hybrids for added options
With multicompressor units, the choice is between hybrids in which conventional compressors are used concurrently with inverter-powered compressors versus solely inverter-powered compressors. This allows customers to always strike the right balance between energy efficiency and cost, depending on the application. The combination of an inverter and screw or scroll compressors offers the highest efficiency, while the operational limits are equivalent to those for conventional units.
Maximised control of cooling water!
Control and monitoring are key as regards the flow and temperature of cooling water. By permitting higher temperatures in the cooling water when load values are low, efficiency is boosted, and with increased use of free cooling, compressor run-time is reduced. Conversely, if humidity requirements can be eased, the cooling water temperature can then by way of compensation be kept lower, since dehumidification will be more rapid and effective.
Server rooms require powerful but compact cooling systems
The ideal server room solution is a unit with a direct expansion, distanced condenser with vertical flow and air distribution directly into the server room. This allows various installation requirements to be met in one, and the installation will be dependable and efficient, and customisable by the customer.
Integrated solutions for small-scale data centres provide a high kW/m2 quotient on minimal floor space
In spite of the name, small data centres often spell high energy density if they run blade servers. This is best catered for with blade chillers, which efficiently eliminate high volumes of hot air. This solution eliminates the need for raised flooring for air distribution, which reduces upfront installation costs.
For medium-sized data centres, we offer proprietary and energy-efficient solutions
Where the centre will be operating 24/7/365, the combination of indoor-installed, water-chilled units for air conditioning plus chillers for free cooling provides the most energy-efficient solution on the market. One typical configuration uses the air flow under raised flooring with racked solutions in warm versus cold corridors, which maximises energy handling capability, operations and a high kW/m2 quotient.
For centres dealing with very high heat generation, the best choice will usually be large air chilled and inverter-driven chillers.