Worldwide Data centers (DC) are estimated to account for 1 to 2% of electricity usage. Regarding the European context, it is expected that data centres will account for 98.5 TWh/year in 2030. So it is evident that there is an important potential to recover waste heat from the cooling processes of DCs. The THUNDER project aims to overcome existing barriers hampering a wide adoption of DCs waste heat recovery strategies, providing an innovative, efficient and cost attractive Seasonal Thermal storage based on Thermochemical Materials. THUNDER solutions stretch across the value chain (data centre innovative storage providers, heat pump manufacturers and district energy company operators). The THUNDER solutions will be validated in field conditions at the Demosite in Bulgaria where the practice of WHR from DC is not widely diffused thus boosting the market also in those areas. Deepened replicability assessment will be done and pre-feasibility analysis developed in 10 further Demosites across all over Europe. Co-design and training workshops will be organized at the replicability identified sites to promote stakeholders engagement and social awareness thus unlocking barriers and make it real THUNDER replication.