Quantification and diagnostics of corrosion-driven energy degradation in closed loop hydronic heating systems

<p dir="ltr">Closed loop hydronic heating systems are commonly used for space heating in buildings but are prone to performance degradation due to corrosion induced fouling, an issue that remains underexplored in building services research. To this end, this novel experimental study quantifies the energy penalties associated with corrosion and evaluates the effectiveness of mechanical filtration in mitigating the corrosion effect and restoring system energy performance. A customised experimental rig was developed to simulate real world operating conditions, with corrosion mimicked by dosing 800 g of magnetite, representing up to 10–20 years of system degradation. The system was tested under various flow rates and pressures capturing different operating conditions to evaluate pump energy performance under clean, fouled, and filtered conditions. A novel non-intrusive approach using infrared thermography was used to visualise and diagnose system behaviour. Results show that corrosion induced fouling can increase pump energy consumption by up to 180 %, and in low pressure conditions, it can cause complete pump failure. Mechanical filtration restored up to 55 % of energy losses, although filter saturation led to diminishing returns, emphasising the need for maintenance. Sediment captures increased non-linearly with hydraulic loading, peaking at 460 g, but excessive accumulation risked system blockages and higher energy demand. The findings highlight the importance of water quality management to ensure optimised energy performance and operational reliability in hydronic heating systems.</p>