Luca Socci

The decarbonisation of the building sector represents a key challenge for the European energy transition, particularly in the heating segment, which is still largely dependent on fossil fuels. In this context, data centres (DCs) offer a promising opportunity as local sources of recoverable waste heat. This study investigates the use of data centre waste heat for building heating through a comparative annual energy analysis applied to two building typologies in a Mediterranean climate (Italy): a residential building and a school. Three scenarios are considered: non-integrated scenario S0 (data centre with its own cooling system and buildings with gas-fired boilers), non-integrated scenario S1 (data centre with its own cooling system and buildings with air-to-water heat pumps), and integrated scenario S2 (data centre cooling system coupled with the buildings through waste heat recovery and heat pump technology). A theoretical 300 kW data centre was considered as the waste heat source. The integrated scenario significantly improves system performance. In the residential case, the seasonal COP increases from 2.15 to 4.50, reducing electricity consumption from 289.5 MWh to 128.9 MWh. In the school case, the COP increases from 2.51 to 8.00, with electricity consumption decreasing from 161.3 MWh to 49.1 MWh. These improvements lead to reductions in non-renewable primary energy demand of up to 63% and 79% for the residential and school buildings, respectively, compared to the baseline scenario. The results demonstrate that data centres can act as decentralised thermal sources, supporting the transition towards low-carbon and Nearly Zero-Energy Buildings.

The rapid growth of data centres is driving higher electricity consumption and continuous generation of low-grade waste heat. Integrating this heat into district-heating networks offers a smart strategy for thermal management in urban areas. In this context, this study presents an energy and exergy analysis of an integrated system comprising a data centre, vapour-compression heat pumps, thermochemical energy storage, and a third-generation district-heating network in Varna (Bulgaria). The proposed system relies on data-centre waste-heat recovery via vapour-compression heat pumps and thermochemical energy storage, enabling seasonal decoupling between heat availability and demand. Despite the relatively small size of the data centre (500 kW) compared to the district-heating system (average thermal demand of 9.3 MW), recovered waste heat can supply up to 3.0% of the annual heat demand and over 20% of the instantaneous load. The integrated configuration consistently improves overall exergy efficiency, confirming its thermodynamic advantage. These findings show that data centres can act as reliable thermal assets for existing district-heating networks, with heat pumps and thermal energy storage emerging as key enablers for district-heating decarbonisation.