HYCOOL-IT: D3.2 Waste heat integration with new gen thermal grids

The goal of HYCOOL-IT project is to develop a set of processes supported by both digital and technical equipment innovative solutions for an efficient and reliable development of IT Server Rooms for advanced tertiary buildings, with a special focus on its replicability through standardisation. In addition, one major project asset is the recovery of waste heat from server rooms into buildings, a solution that will be tested and validated in one of the POLIMI Campus Building undergoing renovation of campus server room as a representative TRL 5 Living Lab, along with Digital Twin solutions for optimal thermal management of server rooms. The purpose of this deliverable is to present an extensive overview and analysis of waste-heat recovery strategies from data centres and its subsequent financial and environmental benefits. The deliverable is structured for presenting three main topics: i) review of IT cooling system technologies, ii) district heating integration strategies for heat recovery of IT server rooms, iii) performance assessment of waste heat integration through MILP modelling and simulations. Different cooling technologies for data centres are presented and discussed, mainly air-based, liquid-based, and innovative adsorption-based cooling systems. Characteristics of each cooling technology are discussed, highlighting working principles, advantages/disadvantages, and case studies with significant results. Integration strategies for data centre waste-heat recovery are presented in detail, placing an emphasis on the main factors to consider, such as waste-heat temperature levels, capture technologies (i.e., heat pumps, heat exchangers), potential financial and environmental benefits, and possible schemes for integration with 4th and 5th generation district heating networks. A numerical simulation done with MILP modelling for assessing waste-heat performance is presented, evaluating three potential server room cooling system schemes in three locations across Europe (Milan, Helsinki, Strasbourg). For each location, country-specific data, including space heating requirements, were also considered, for a total of 27 cases. Simulation results are shown, highlighting performance through KPIs (PUE and ERF), and energy, financial, and environmental savings. Lastly, the specific integration solution in the pilot of the Bovisa Campus at Politecnico di Milano is selected.