Page 313 - A Comprehensive Guide to Solar Energy Systems

Chapter 14 • Advanced Building Integrated Photovoltaic/Thermal Technologies 317

−1
• At a water flow rate of 150 mL min , the output electricity energy E pv reaches 32.96 Epv
and 44.91 W and the PV efficiency η pv reaches 14.51% and 15.82% under solar ηpv
irradiance of 800 and 1000 W m , respectively. The PV efficiency is also enhanced by
−2
21.1% and 24.0% for those two solar irradiances respectively, compared with the case
when no water flow is introduced.
• At an introduced water flow rate of 150 mL min , the total energy efficiency
−1
( T η = η thermal η+ pv ) of the presented BIPVT roofing panel has been evaluated to ηT=ηthermal+ηpv
−2
be79.8%, 77.3%, and 75.2% under solar irradiances of 620, 800, and 1000 W m
respectively.
overall, the test results demonstrate that significant energy conversion efficiency
improvement can be achieved for both electricity generation and heat collection by the
developed BIPVT roofing panel. From the comparisons of the present BIPVT with other
relevant technologies, it was found that the developed BIPVT panel is able to harvest
solar irradiance more efficiently in form of electricity and heat than most PVT or BIPVT
technologies currently described in the literature. due to the temperature control on
the roof, better thermal comfort in the building can be achieved and, therefore, the
energy demand for cooling can be reduced in the summer time. moreover, the warm
water flow can be applied to remove frost or ice on the roof in wintertime, thus further
restore and enhance solar energy utilization. In addition, this BIPVT provides custom-
ers with great flexibilities to adjust the water flowing rate to meet each home’s specific
requirements.

Acknowledgment

This work is sponsored by the national Science Foundation CmmI 0954717, whose support is gratefully
acknowledged. The authors appreciate the contributions from mr. yuda Sun, mr. Xin He, mr. Bin li, mr.
Joao Silva, and mr. rodolfo Kusmaonthe on laboratory testing and the ongoing support from the Henry
mitchell Weitzner research Fund.

References

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