Energy modeling of photovoltaic thermal systems with corrugated unglazed transpired solar collectors – Part 2: Performance analysis

• Investigated the energy performance of UTCs and UTCs with PV/T.
• Identified important climate and design parameters.
• Examined the impact of collector geometry, orientation, and incident turbulence intensity.
• Organized a set of performance curves.
• Provided valuable guidelines for design and analysis.

This paper is the second of two companion papers focused on energy modeling and performance analysis of building-integrated photovoltaic thermal (PV/T) systems with corrugated unglazed transpired solar collectors (UTCs). In Part 1, energy models are presented for two configurations: UTC only and UTC with PV panels. The models predict the energy output of the system for different weather and system design conditions and are validated using measured data from an outdoor test facility. In this paper (Part 2), the system performance is evaluated based on data drawn from the literature and simulations with Computational Fluid Dynamics (CFD) and energy models. The analysis includes parameters that are unique for this system, such as the corrugation geometry and the collector orientation. Validated, high resolution CFD simulations are used to study the impact of plate orientation and incident turbulence intensity, based on the comparison of exterior and interior Nusselt (Nu) number and the cavity exit air temperature, as well as the PV surface temperature when UTCs are integrated with PV panels. It is found that for configurations with UTC only, both exterior and interior convective heat transfer is enhanced in the ‘vertical’ installation, while similar results were obtained for increased incident turbulence intensity levels. However, only minor influences from these two parameters are observed for UTCs with PV panels. The energy model is used to investigate the optimal geometry for both configurations. It is found that parameters such as slope length and corrugation wavelength have the most significant impact on UTC performance while the wavelength and PV panel height have the largest effect for UTCs with PV panels.