Performance improvement of photovoltaic modules via temperature homogeneity improvement

Abstract

Though the PV module performance can be enhanced by cooling, the associated temperature non-uniformity across the PV panel can deteriorate its efficiency. In this study, a significant effort is conducted for an air-cooling system that can control the temperature uniformity across the PV panel. The cooling of a rooftop PV module is enabled by the air-conditioning unit installed on the building’s roof. PV panel performance, with and without the cooling, is experimentally investigated for the uniform cold air duct. Experimental results showed that the cooled panel temperature is 6–12 °C lower than that of the uncooled one. However, even with the cooling, the temperature non-uniformity of 4–7 °C was noticed across the PV panel. To improve the temperature uniformity across the module, converging cold air ducts with different area ratios (AR) of 0.667 and 0.333 were designed and analyzed numerically. The effect of inlet air temperature (Tin-air = 18–23 °C) and inlet airflow velocity (U = 2–3 m/s) on panel temperature were also studied. The results suggested that the PV panel with CCD having an AR of 0.333 exhibited a temperature non-uniformity of 1.5–2.5 °C and demonstrated a 17–22% improvement in module efficiency under Tin-air = 18 °C and U = 3 m/s.