Validation of Thermal Models for Bifacial Photovoltaic Systems under
Various Albedo Conditions
Abstract
This study evaluated the performance of three photovoltaic (PV) module
operating temperature models — Ross, Faiman, and PVsyst® — using
different measurement time resolutions for bifacial PV systems under
various albedo conditions. This work also analyzed the application of
the models with the use of effective irradiance - including front and
rear-side plane of array irradiance - for the estimation of bifacial PV
module temperature. The calculated heat transfer coefficients for each
evaluated scenario are presented and discussed in detail. A comparison
of all simulated cases was carried out to recommend the most suitable
model for each situation. Additionally, the use of estimated cell
operating temperature from back-of-module temperature was evaluated
across all scenarios. As expected, hourly resolutions provided better
results for all scenarios, having the lowest error for temperature
estimations across different models and ground (albedo) types. Using
calculated coefficients and taking into account rear-side irradiance
resulted in more accurate temperature predictions, emphasizing the
importance of model adaptations and refined parameterization. The
results for different heat transfer coefficients varied significantly
among the models. Ross’s model applied with standard values (k between
0.2 and 0.4) showed close alignment with measured data. In contrast,
Faiman’s model with standard coefficients ( U 0 between 24 and 27
W/m²·°C, U 1 between 6 and 8 W/m²·°C/m/s) and PVsyst’s standard
coefficients ( U c =29 W/m²·°C, U v =0 W/m²·°C/m/s) exhibited
significant deviations. Adjusted coefficients for PVsyst ( U c =40
W/m²·°C, U v =0 W/m²·°C/m/s) provided better accuracy. The standard
PVsyst coefficients presented better results when compared against
cell-adjusted temperature estimates, rather than back-of-module measured
values. This discrepancy can lead to significant estimation errors in
both temperature output performance and for bifacial modules.
Highlights Analysis of PV module temperature models taking into
account rear-side irradiance for bifacial PV systems Evaluation of
temperature models applied to bifacial PV modules exposed to various
albedo levels and at different time resolutions Estimation of heat
transfer coefficients for bifacial PV modules