Energy and Carbon Savings in Data Centres Through Liquid-to-Chip Cooling with Differential Temperature Control

• Converting data centres from air-to-chip (ATC), to liquid-to-chip (LTC) could reduce peak energy demand per kWhr of compute by 6%–14% • Annual energy consumption, carbon emissions, and power usage efficiency (PUE) may be improved by 4%–13% per kWhr of compute by data centre conversion from ATC to LTC • Increasing fluid differential and supply temperatures for LTC systems can eliminate the need for high energy use refrigerant compressor chillers in Australian and Asian climates. • Applying the novel control method to increase fluid differential temperatures from 5°C to 10°C based on I.T. kW measurement for LTC data centres could improve total data centre efficiency between approximately 3%∼6%, reduce PUE from a range of 1.22∼1.25 to 1.18 and potentially reduce central plant energy 18∼28%. The rapid and large-scale development of data centres to manage computational demand is resulting in potential strain on electrical energy and water utilities globally. New methods for minimising the peak power demand and annual energy of data centres that can be adapted to the different ambient conditions of various geographic locations are urgently needed. This study applies a novel advanced method of energy savings by differential temperature control via I.T. kW load measurement, to the conversion of data centres from conventional air-to-chip (ATC) cooling, to new liquid-to-chip (LTC) cooling. The novel method potentially assists elimination of energy-intensive chillers in favour of free cooling, reduces peak power demand and annual energy consumption for temperate to tropical ambient conditions. A new energy model was developed in Design Builder TM and EnergyPlus TM and was validated by onsite measurements at a state-of-the-art data centre in Melbourne, Australia and utilised to predict and optimize the improvement in energy efficiency by controlling differential temperature. The results indicate that converting from ATC cooling to LTC cooling could reduce the total peak power demand by 6%∼14% and reduce the annual energy consumption, carbon emissions and power usage efficiency by 4%∼13%. Application of the advanced control method to increase differential temperature from 5°C to 10°C for LTC systems, predicted reduction of the PUE from a range of 1.22∼1.25 to 1.18, potentially contributing an 18∼28% reduction in central plant energy.