Energy

Sustainability In The Cooling Of Data Centres And Reduced Energy Consumption

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<p style="text-align: justify;">The industrial processes on a whole and, for example IT systems must continuously be improved with regard to energy consumption.</p><p style="text-align: justify;">The Fraunhofer Institute for Systems and Innovation Research in Karlsruhe has deter-mined that the energy consumption of data centres in Germany currently is around 10-15TWh. Converted into CO2 equivalents, this roughly corresponds to the CO2 emissions from air traffic in Germany (before Corona). The share of the IT industry in global en-ergy consumption is around 7%. The same report also said that Google's energy con-sumption increased by 20% from 2015/2016. The cooling of the systems alone accounts for approx. 25% of the total energy consumption, so savings potential must be sought here.</p><p style="text-align: justify;">Data centres around 1980 worked with room temperatures around 18-20 &deg;C. At that time, these temperatures could only be achieved by means of ozone-damaging com-pression cooling, i.e. the energy consumption of the cooling was well over 35% due to the high proportion of compression cooling and moreover, it was also harmful to the environment.</p><p style="text-align: justify;">With new technologies and location decisions the IT industry tried to get the operating costs for the "cooling" under control.</p><p style="text-align: justify;">Over the years processes in the computers have been improved, and the cooling works with higher cooling water temperatures. Due to the higher cooling water temperatures, the difference to the rising outside temperatures around the world is smaller. The com-pression refrigeration is only necessary to maintain operational reliability, the annual operating hours and thus the operating costs, are cut back to a few hundred hours per year, which means a significant reduction. For more than 8000h/a, the cooling capacity is provided by free cooling, i.e. by ambient air or ambient air pre-cooled by water - dry coolers, also with adiabatic pre-cooling, hybrid coolers and cooling towers are used here.</p><p style="text-align: justify;">After all, the future in this field is in the use of hybrid technology. Quiet dry coolers with a large heat exchange surface and high-efficiency fans will work in dry mode up to outside temperatures of 25-30 &deg;C. Above such outside temperatures, the cooling air will be pre-cooled adiabatically while the heat exchanger is cooled directly with water.</p><p style="text-align: justify;">Related to Hamburg, the annual operating costs for a cooling capacity of 1,000kW can be reduced to less than 1,000&euro; (electricity 0.16 &euro;/kWh and cooling water 4&euro;/m3/h).</p><p style="text-align: justify;">Energy savings in the cooling of data centres could significantly be increased if comput-ers are developed that work constantly and safe even at higher operating temperatures. Ideally, there should be a dry heat transfer by convection from the data centre to the outside air or via plate heat exchangers to the district heating system.&nbsp;</p>
KR Expert - Reinhard Grauting