Review of Waste Heat Utilisation from Data Centres

Rapidly increasing global internet traffic, mobile internet users and the number of Internet of Things (IoT) connections are driving exponential growth in demand for data centre and network services, which in turn is driving their electricity demand. Data centres now account for 3% of global electricity consumption and contribute to 4% of the global greenhouse gas emissions. This study discusses the potential of reusing the waste heat from data centres. An overview of imbedding heat recovery systems into data centres is presented. The implications of economic cost and energy efficient heat recovery systems in data centre buildings are also discussed. The main problems with implementing heat recovery systems in existing data centre designs are (i) high capital costs of investment and (ii) low temperatures of the waste heat. This study suggests alternatives that could allow data centre operators to utilise waste heat with more efficiencies. It also discusses how liquid-cooled data centres can be more efficient in utilising their waste heat than the air-cooled ones. One possible solution suggested here is that data centre operators can decrease their environmental impact by exporting waste heat to the external heat networks. The barriers in connecting datacentres to heat networks are discussed and suggestions to overcome those barriers have been provided

Assessment of real-time data transmission via ad-hoc communication networks in the North Atlantic oceanic airspace

Data link based real-time data transmission for air traffic services and aeronautical operational control provides for safe, efficient and timely exchange of information between aircraft and ground entities within the current air transportation system. This enables procedures and process optimization for air traffic service and airline operational control. Currently, the air transport system relies on direct line-of-sight data link in continental airspace and communication via satellite or high frequency data link in oceanic, remote or polar airspace. Future communication technology intends to additionally allow for indirect air-to-ground communication via aeronautical ad-hoc networks using aircraft as network nodes. This approach bears a high potential to increase airspace capacity and efficiency for congested airspaces with little ground infrastructure as it is the case e.g. for the North Atlantic oceanic airspace. While the assessment of operational benefits for conventional line-ofsight or satellite-based data link technologies can be based on the experience made with existing technologies, the assessment of aeronautical ad-hoc networks needs careful consideration of the particular air traffic situation as well as of the specific aeronautical communication demand. In our work we present a method to combine air traffic and connectivity simulations with an aeronautical data traffic demand model for the North Atlantic oceanic airspace. As a result, the coverage of aeronautical data traffic demand by an aeronautical adhoc network enabled by the new technology, will be estimated for various scenarios for the North Atlantic oceanic airspace. Dependencies on the equipage fraction and on the air-to-air radio range will be analyzed. Also, expected application data rates at aircraft exchanging the data communication of the airborne network with ground entities, will be assessed on a simplified basis. The results are suited to serve as a technical guidance for further scaling and definition of the underlying air-to-air data link technology

Increasing resilience of ATM networks using traffic monitoring and automated anomaly analysis

Systematic network monitoring can be the cornerstone for the dependable operation of safety-critical distributed systems. In this paper, we present our vision for informed anomaly detection through network monitoring and resilience measurements to increase the operators' visibility of ATM communication networks. We raise the question of how to determine the optimal level of automation in this safety-critical context, and we present a novel passive network monitoring system that can reveal network utilisation trends and traffic patterns in diverse timescales. Using network measurements, we derive resilience metrics and visualisations to enhance the operators' knowledge of the network and traffic behaviour, and allow for network planning and provisioning based on informed what-if analysis