Intelligent Data Centres Issue 01 | Page 41

FEATURE THERE ARE THREE COMMON SPECIFICATION CHOICES FOR DATA CENTRE COOLING; TRADITIONAL COOLING TOWERS, HYBRID COOLERS AND ADIABATIC SYSTEMS. lectricity and water are the two main resources required for data centre operation, yet for the UK data centre market, the use of water remains of little concern compared to its counterpart sectors around the world. A recent US Geological Survey has suggested that by 2020, data centres across the pond will consume around 660 billion litres of water per year, making the US data centre market one of the highest consumers of a rapidly depleting natural commodity. The statistics are on a similar scale for the UK, with data centres relying heavily on water in order to regulate and maintain internal temperature, especially in facilities using traditional cooling tower methods compared to more efficient hybrid or adiabatic systems. In the US, water consumption (or lack of it) is a critical component in the specification of cooling equipment, even more so since California’s drought in the summer of 2015 shone a light on the commercial use of water. While it is arguable that weather variables make water more abundant in the UK and therefore make it less of an immediate concern, many manufacturers of water- conscious and highly efficient cooling equipment believe that saving water should be a moral decision in the same way recycling and reuse of other precious resources has become. The conservation of water is a humanitarian issue and one which should rightfully cause political and social concern at a global level, not just in the countries which experience drought or have geographies which are synonymous with less abundant natural resources. The latest statistics from the United Nations states that in industrialised nations, industry consumes 80% of water available for human consumption, with the World Health Organisation stating that half the world’s population will be living in ‘water-stressed’ areas by 2025. These statistics – and many more like them – should make one of the world’s most progressive and technologically advanced industries sit up and take note of its consumption rates and, more importantly, what it can do to improve the environmental impact of its mission critical operational processes. Cooling towers, hybrid and adiabatic technology – the truth about their water consumption There are three common specification choices for data centre cooling; traditional cooling towers, hybrid coolers and adiabatic systems. Cooling towers are most frequently specified for budget projects or those with severe space restrictions, whilst hybrid equipment has long been the habitual specification choice for data centre designers unsure of the true benefits of switching to adiabatic alternatives. All three options will save significant amounts of energy when compared to typical compressor based chilled water systems and can achieve far higher Energy Efficiency Ratios (EER). As modern data centres are designed with higher supply air temperatures they are also increasingly used as the primary source of cooling rather than rejecting heat from chilled water plants. Take the example of a typical compressor- based chiller which will consume 1kW of energy for every 3-4kW of cooling delivered. Compare this to an equivalent sized adiabatic solution, which for the same 1kW of energy consumed, will deliver up to 75kW of cooling. Issue 01 41