Optimization on the structure and filling ratio of a flexible separate heat pipe applied for tracking-type photovoltaic/thermal systems

Abstract

The utilization of photovoltaic/thermal (PV/T) systems with separate heat pipes holds significant potential to improve solar energy efficiency by addressing issues like winter freezing and scaling. However, challenges such as frame shading due to increased insulation needs could hinder overall efficiency. In the previous study, a novel flexible separate heat pipe (FSHP) employed in the tracking-type PV/T system was introduced, effectively avoiding the effects of frame shading. This research aims to further optimize the structure of the flexible separate heat pipe through experiments, exploring the impact of factors such as the diameter and material of the adiabatic pipes, evaporator-condenser height difference, and filling ratio on the thermal performance. Furthermore, the study will delve into the system's thermal performance at dissimilar solar irradiance and side-altitude inclination angles. The experimental results demonstrate that the enhanced structure significantly boosts thermal efficiency, stabilizing it between 69.37 % and 79.71 %. This study offers a fresh perspective for enhancing the performance of the FSHPs and explores their potential for broader solar energy use.