Data Center Energy Retrofits

Within the field of computer science, data centers (DCs) are a major consumer of energy. A large part of that energy is used for cooling down the exhaust heat of the servers contained in the DCs. This thesis describes both the aggregate numbers of DCs and key flagship installations in detail. We then introduce the concept of Data Center Energy Retrofits, a set of low cost, easy to install techniques that may be used by the majority of DCs for reducing their energy consumption. 

The main contributions are a feasibility study of direct free air cooling, two techniques that explore air stream containment, a wired sensor network for temperature measurements, and a prototype greenhouse that harvests and reuses the exhaust heat of the servers for growing edible plants, including chili peppers. We also project the energy savings attainable by implementing the proposed techniques, and show that global savings are possible even when very conservative installation numbers and payback times are modelled. 

Using the results obtained, we make a lower bound estimate that direct free air cooling could reduce global greenhouse gas (GHG) emissions by 9.4 MtCO2e already by the year 2005 footprint of the DCs. Air stream containment could reduce the GHG emissions by a further 0.7 MtCO2e, and finally heat harvesting can turn the waste heat into additional profits. Much larger savings are already possible, since the DC footprint has increased considerably since 2005.