ZEMCH 2019 International Conference Proceedings April.2020 | Page 391
14.63%, respectively. It is observed that the exergy efficiency for the glass to glass case is higher than
that of glass to tedlar case. It can be explained by the fact that due to glass to glass PV protection the
rate of heat extraction by the circulating fluid from the PV module increased and hence there is a
reduction in PV cells temperature.
Figure 6. Variations of overall oxergy efficiency against day hours.
The long‐term performance of a dual‐fluid PV/T considering both cases is evaluated by taking
monthly average solar radiation and ambient temperature. Figures 7 and 8 show the variation trends
of monthly average electrical and thermal efficiency for both cases across the whole year. The maximum
electrical efficiency for glass to tedlar and glass to glass cases are observed in March with value 15.1%
and 15.5%, respectively, whereas in July these values were reduced to minimum level of 12.71% and
12.45%, respectively. The yearly average total thermal efficiency for glass to tedlar and glass to glass
cases are observed to be 53.24% and 57.92%, respectively. Apart from different configurations, both
cases produced the reasonably good thermal efficiency in comparison with conventional single fluid
exchangers. However, due to direct transmission in case of glass to glass PV/T system the blackened
back panel was heated continuously by the incident solar radiation. Therefore, the glass to glass case
has higher circulating fluids temperature and thermal efficiency than that of glass to tedlar case. It can
be noticed that the maximum overall efficiency (electrical plus thermal) of both cases was observed in
spring months (March and April). This trend can easily be explained by more number of sunshine hours
and lower ambient air temperature.
Performance Evaluation of Photovoltaic/Thermal (PV/T) System Using
Different Design Configurations
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