Worldwide energy analysis of major free cooling methods for data centers

Climate- and Technology-Specific PUE and WUE Predictions for U.S. Data Centers using a Physics-Based Approach

“…To arrive at this estimate, the authors assumed a nationwide average DC on-site water consumption of 1.8 liters per kWh of total DC site energy use. More recently, Sharma et al performed a time-series analysis of the energy and direct water use of a DC employing a water-cooled chiller system with a waterside economizer in western Massachusetts using monitored data (Sharma et al, 2017 (Gozcu et al, 2017). However, the modeling methodology of this study was not clearly documented, and the modeling results were not verified using real DC operation data.…”

“…Second, direct water use estimates have mostly been limited to a small set of cooling technologies in a few specific locations without revealing important technical parameters that may impact WUE in those locations, such as equipment efficiencies and set points. Third, all but one study (Gozcu et al, 2017) analyzed the direct water use of single DCs in specific locations, and using data from a small number of representative days, which prohibits exploration of how climate variations by location would affect WUE. Even so, the study by Gozcu et al applied static equipment power and water use profiles and did not explore how DC facility system variations would affect WUE.…”

The role of data centres in the future Danish energy system

“…𝜟𝒑 𝒇𝒂𝒏,𝑰𝑨𝑺𝑬,𝒎𝒂𝒙 Pa 400 Additional pressure drop for moving DC air through HX [31] 𝜟𝒑 𝒇𝒂𝒏,𝑪𝑹𝑨𝑯,𝒎𝒂𝒙 Pa 700 Pressure drop for recirculating air inside data hall [31] 𝑻 𝒂𝒊𝒓,𝒓𝒆𝒋𝒆𝒄𝒕𝒆𝒅 °C 20 Assumed air outlet temperature after heat recovery A vapour compression air-cooled chiller associated with an indirect airside economizer (IASE) is assumed for cooling system configuration [12]. Depending on the outdoor air temperature, two cooling modes can be performed: "free cooling" through IASE, or chiller mode.…”

“…The airflow supplied to the data hall should not be the exact amount required to cool the equipment due to by-pass effects [12,31]. Therefore, the total airflow recirculating inside the data hall is expressed by eq.…”

“…Similarly, Depoorter et al [11] created a model for coupling the server's power consumption and heat dissipation with a specific free-cooling strategy in a sample facility located in various European cities. Gozcu et al [12] instead simulated the annual power consumption of four different free-cooling strategies in several places around the world, but did so by disregarding the modelling of the heat dissipated by the information technology (IT) equipment by assuming it to be equal to the absorbed power. A further methodology was presented by Pelley et al [13], who proposed a parametric model for abstracting the total power demand of a DC and then analysed different efficiency scenarios involving both optimal cooling and IT equipment management.…”