Experimental investigation of a windthermal demonstrator with friction based direct wind-to-heat conversion

Abstract

This experimental investigation delves into the prospective application of windthermal energy, the direct conversion of wind turbine rotational energy into heat. Therefore, we developed, constructed, and validated a friction-based windthermal demonstrator that consists of a wind turbine and a thermal platform with a hydrodynamic retarder. This paper explains the experimental arrangement of the demonstrator and analyses exhaustively the thermal platform's dynamics, its heat generation performance and auxiliary systems. In a two-step approach, we conducted motor-driven preliminary experiments to validate and optimize the experimental set-up, and then we conducted wind-turbine-driven main experiments. The results confirm that the demonstrator can effectively capture heat from wind energy, with a peak-load of 8 kW and an overall system efficiency of 8.73 %. Besides this low efficiency, we identified challenges like off-design behavior of the hydrodynamic retarder and operational temperature constraints. The efficiency could be improved by optimizing the retarder, refining the shaft system, and enhancing the insulation. Considering these optimization approaches, the demonstrator shows that windthermal energy could potentially contribute to a sustainable heat generation.