Understanding heat dissipation factors for fixed-tilt and single-axis tracked open-rack photovoltaic modules: experimental insights

TL;DR

This study experimentally investigates heat dissipation in fixed-tilt and single-axis tracked open-rack PV modules, revealing factors influencing module temperature and demonstrating performance improvements through realistic heat dissipation modeling.

Contribution

It provides novel heat dissipation factors for SAT modules and assesses their impact on module temperature prediction and power output in real-world conditions.

Findings

Enhanced heat dissipation in SAT modules under low wind conditions

Heat dissipation factors significantly influence power output simulations

Minimal sensitivity of temperature predictions to heat dissipation factor variations

Abstract

This paper presents the results of long-term experiments conducted on fixed-tilt (FT) and single-axis tracked (SAT) open-rack photovoltaic (PV) modules in South Africa. Utilizing Faiman's heat dissipation model and data filtering method, the study demonstrates favourable comparisons of FT experimental results with literature, while yielding novel heat dissipation factors for SAT modules. Enhanced heat dissipation is observed in no/low wind conditions for SAT modules compared to FT modules. Analyses reveal the influence of plane-of-array (POA) irradiance, wind speed and direction on module temperature, with SAT modules exhibiting greater heat dissipation stability. An investigation into data filtering methods suggests minor sensitivity for both configurations, with a slightly more pronounced impact on SAT modules. Assessments comparing module temperature predictions using diverse heat dissipation factors for FT modules reveal negligible sensitivity. This suggests that exact heat dissipation factor values may not be crucial for accurate predictions of module temperature in FT open-rack systems. Annual power output simulations using PVsyst software demonstrate a 2.9% and 3.3% enhancement for FT and SAT configurations, respectively, when employing experimentally determined heat dissipation factors. These findings highlight the importance of realistic, configuration-specific heat dissipation factors in optimizing PV system performance, particularly in the competitive context of modern PV power plant construction and techno-economic calculations.