Experimental Investigation of Heat Losses in Hydrogen-Doped Parabolic Trough Receivers

This study investigates the impact of hydrogen presence in the annulus space of heat-collecting elements (HCEs) used in parabolic trough solar power plants. Hydrogen, formed during degradation of the heat transfer fluid diphenyl oxide/biphenyl (DPO/BP), can permeate into the annulus and significantly increases heat loss due to enhanced conductive heat transfer. Following the resistance heating method defined tin the technical specification IEC TS 62862-3-3, heat loss measurements were conducted on HCEs before and after hydrogen doping at various absorber temperatures (100–400 °C). Results showed heat losses up to four times higher in hydrogen-doped receivers, reaching 867 W/m at 400 °C, compared to 211 W/m in evacuated units. Uncertainty analysis confirmed measurement reliability. The data confirms hydrogen’s detrimental effect on thermal performance and supports the need for improved hydrogen control in operational solar power plants with parabolic troughs.