Waste heat as a building retrofit strategy: Unlocking data centre thermal energy for decarbonising existing commercial and residential buildings

Data centres reject megawatts of continuous thermal energy that is almost always wasted. This presentation introduces a simulation framework comparing three strategies for recovering data-centre waste heat and integrating it into the heating and cooling systems of existing commercial and residential buildings. Strategies span low-grade heat pump–assisted recovery (35–42°C server exhaust), hydrogen fuel-cell co-generation (70–85°C), and high-temperature solid-oxide fuel-cell thermal cascading (700–850°C exhaust) enabling multi-stage absorption cooling plus 70°C district-heating supply. Key findings show thermal efficiency over 70%, operating cost reductions of 20–35%, and carbon savings up to 350 tonnes CO₂ per year per building cluster, delivered through practical retrofit integration with existing hydronic loops and gas-boiler plant-room conversions. A decision framework guides facility managers in judging feasibility by building type.