Data centres consumed roughly 2 % of European electricity in 2024, rising to approximately 3 % within the EU alone (International Energy Agency, 2025). Demand is projected to grow a further 70 % by 2030, yet nearly all input energy is dissipated as heat that is seldom recovered. The EU Energy Efficiency Directive (2023/1791) now mandates waste heat reporting for facilities above 500 kW of installed IT capacity, but reporting alone does not deliver heat to nearby buildings or district networks. Doing so requires linked monitoring and control across weather forecasts, building demand, the cooling plant, and IT workload. This paper presents the software architecture of a modular digital twin platform that integrates these four domains, evaluated at a laboratory-scale liquid-cooled pilot at the RISE ICE Datacenter. Heat to workload coordination today runs through policy-based planning rules, with a numerical optimiser variant under development. Developed within the EU Horizon Europe HEATWISE project, the platform is built from a pipeline of Julia and Go microservices behind a reactive web dashboard. Its contributions are architectural: a server-authoritative reactive model shared across all connected operators via WebSockets; a deployment split that withholds hardware credentials from simulation containers, so what-if analysis cannot reach pumps, fans, or valves; an in-process Model Context Protocol (MCP) server that gives AI agents the same state view as human operators; and a centralised MQTT bridge for all hardware communication. Each model in the pipeline (weather forecasting, building heat demand, cooling loop simulation, workload-heat coordination) occupies a replaceable service slot behind a defined HTTP contract (endpoints and schemas), so that site-specific models can be substituted without altering the platform. The platform is deployed at the RISE ICE Datacenter in Luleå, Sweden, with ZutaCore HyperCool two-phase direct-to-chip cooling across blade servers and thermal load emulators. Prior characterisation on Open Compute Project (OCP) servers reached up to 90 % liquid-side heat capture at full load [13], and the project targets an Energy Reuse Factor (ERF) of 95 % or above pending system-level measurement.

The increasing penetration of variable renewable energy resources and new demands have significantly heightened the need for flexibility in power systems. Data centres present a unique opportunity to enhance power system flexibility due to their substantial yet controllable energy consumption and advanced technological capabilities. This paper provides an in-depth analysis of the potential role of data centres in improving power system flexibility. Initially, the flexibility requirements of modern power systems are defined, followed by an exploration of the flexibility assets and operational flexibility capabilities of data centres. Then, the flexibility capacities of data centres are examined, and the opportunities and benefits of leveraging this flexibility are explored, supported by case studies illustrating real-world examples. This paper underscores the vital role of data centres in the evolving energy landscape. In particular, the analysis reveals that data centres have a high potential to address the increasing flexibility requirements driven by the integration of renewable energy and the transition towards net-zero emission goals. Moreover, the findings emphasise key challenges, including ensuring Quality of Service (QoS) and adherence to Service Level Agreements (SLA), the need for further legislative development to facilitate data centres’ participation in energy markets and the provision of ancillary services, as regulatory frameworks differ across regions and variations exist in energy market structures. The findings provide actionable insights for policymakers, industry stakeholders and data centre operators, demonstrating how data centres enhance the stability, flexibility and efficiency of power systems

This study presents a detailed performance evaluation of a graphene-enhanced thermal interface material (TIM) conducted at RISE ICE Data Center. Tests were performed on Open Compute Project (OCP) Leopard servers using three different TIMs: conventional thermal paste, graphene-enhanced thermal pad GT90 from SHT Smart High Tech AB (SHT), and indium foil. Three sets of experiments were conducted: (1) air cooling with default chassis fan control in a bespoke server wind tunnel, (2) air cooling with controlled, fixed fan speeds and different heatsink mounting pressures operating in the wind tunnel and (3) immersion cooling tests with two coolant flow rates at fixed inlet temperatures. Results indicate that graphene-enhanced TIM and thermal paste exhibit similar performance in experiment (1), whereas indium foil TIM tests showed the undesired effect of increased CPU temperatures. In experiment (2), servers equipped with graphene-enhanced TIM showed lower CPU temperatures in comparison to the servers equipped with Indium foil TIM. In experiment (3), immersion cooling resulted in lower CPU temperatures overall, with the graphene-enhanced TIM again providing lower temperatures than indium foil at a similar mounting pressure. The findings suggest that the interfacial thermal conductivity and material compatibility of the GT90 TIM contribute to an improved performance in the tested immersion cooling system as well as the importance of mounting pressure. 

This study presents a detailed performance evaluation of a graphene-enhanced thermal interface material (TIM) conducted at RISE ICE Data Center. Tests were performed on Open Compute Project (OCP) Leopard servers using three different TIMs: conventional thermal paste, graphene-enhanced thermal pad GT90 from SHT Smart High Tech AB (SHT), and indium foil. Three sets of experiments were conducted: (1) air cooling with default chassis fan control in a bespoke server wind tunnel, (2) air cooling with controlled, fixed fan speeds and different heatsink mounting pressures operating in the wind tunnel and (3) immersion cooling tests with two coolant flow rates at fixed inlet temperatures. Results indicate that graphene-enhanced TIM and thermal paste exhibit similar performance in experiment (1), whereas indium foil TIM tests showed the undesired effect of increased CPU temperatures. In experiment (2), servers equipped with graphene-enhanced TIM showed lower CPU temperatures in comparison to the servers equipped with Indium foil TIM. In experiment (3), immersion cooling resulted in lower CPU temperatures overall, with the graphene-enhanced TIM again providing lower temperatures than indium foil at a similar mounting pressure. The findings suggest that the interfacial thermal conductivity and material compatibility of the GT90 TIM contribute to an improved performance in the tested immersion cooling system as well as the importance of mounting pressure.

The energy sector is essential in the transition to a more sustainable future, and renewable energies will play a key role in achieving this. It is also a sector in which the circular economy presents an opportunity for the utilisation of other resources and residual energy flows. This study examines the environmental and social performance of innovative energy technologies (which contribute to the circularity of resources) implemented in a demonstrator site in Luleå (Sweden). The demo-site collected excess heat from a data centre to cogenerate energy, combining the waste heat with fuel cells that use biogas derived from waste, meeting part of its electrical demand and supplying thermal energy to an existing district heating network. Following a cradle-to-gate approach, an environmental and a social life cycle assessment were developed to compare two scenarios: a baseline scenario reflecting current energy supply methods and the WEDISTRICT scenario, which considers the application of different renewable and circular technologies. The findings indicate that transitioning to renewable energy sources significantly reduces environmental impacts in seven of the eight assessed impact categories. Specifically, the study showed a 48% reduction in climate change impact per kWh generated. Additionally, the WEDISTRICT scenario, accounting for avoided burdens, prevented 0.21 kg CO2 eq per kWh auto-consumed. From the social perspective, the WEDISTRICT scenario demonstrated improvement in employment conditions within the worker and local community categories, product satisfaction within the society category, and fair competition within the value chain category. Projects like WEDISTRICT demonstrate the circularity options of the energy sector, the utilisation of resources and residual energy flows, and that these lead to environmental and social improvements throughout the entire life cycle, not just during the operation phase. 

This article investigates the problem of where to place the computation workload in an edge-cloud network topology considering the trade-off between the location-specific cost of computation and data communication. For this purpose, a Monte Carlo simulation model is defined that accounts for different workload types, their distribution across time and location, as well as correlation structure. Results confirm and quantify the intuition that optimization can be achieved by distributing a part of cloud computation to make efficient use of resources in an edge data center network, with operational energy savings of 4–6% and up to 50% reduction in its claim for cloud capacity.

Server power densities are foreseen to increase, and conventional air-cooling systems will struggle to cope with thermal demand. Single-phase immersion systems are a promising alternative to operate very intensive workload such as high-performance computing, cryptocurrencies mining or research activities. However, few companies deal with this kind of system and there is a lack of energy models that can reproduce an accurate analysis of the system behaviour. This study addresses the experimentation, data collection, and model validation of a single-phase immersion cooling system where 54 open compute project servers, each with a peak power of 400 Watts that are submerged and operated in a dielectric coolant. Results show the evolution of the thermal profile of the system under static and dynamic workloads, and it provides a correlation of server energy use under various system temperatures. The energy model is presented, validated against real data, and exploited to investigate the system response to different cooling conditions. In conclusion, the study demonstrates the validation of the energy model and supports the basis for further investigation. © 2023 The Authors

This report investigates the problem of where to place computation workload in an edge-cloud network topology considering the trade-off between the location specific cost of computation and data communication.

A multiphysics Simulation-Driven Design approach has been undertaken to augment the OCP Leopard Server thermal management and heat recovery hardware with the Nexalus hybrid liquid-cooled sealed server technology. Independent testing at the RISE Research Institute of Sweden has proven up to 98% heat recovery is achievable at water temperatures up to and exceeding 65°C. The improved design could maintain the elevated water temperature over a range of CPU workloads, ranging from 8% to 75%. Importantly, the design solution achieves this within an architecture that is IOU in height, half that of the original stock 20U server, potentially doubling the compute density of a rack. 

Low latency requirements are expected to increase with 5G telecommunications driving data and compute to EDGE data centers located in cities near to end users. This article presents a testbed for such data centers that has been built at RISE ICE Datacenter in northern Sweden in order to perform full stack experiments on load balancing, cooling, micro-grid interactions and the use of renewable energy sources. This system is described with details on both hardware components and software implementations used for data collection and control. A use case for off-grid operation is presented to demonstrate how the test lab can be used for experiments on edge data center design, control and autonomous operation. © 2020 Author.