Page 311 - A Comprehensive Guide to Solar Energy Systems

Chapter 14 • Advanced Building Integrated Photovoltaic/Thermal Technologies 315

Table 14.3 Comparison of Panel Efficiencies Among Different Studies
Radiation
BIPVT Daily Transient
−2
Study (Yes/No) (MJ m ) (W m ) η PV (%) η thermal (%) η PVT (%)
−2
Huang et al. [39] No 6.6 ∼ 15.9 – ∼9 12.2 ∼ 44.5 21.2 ∼ 53.5
He et al. [16] No 10.5 ∼ 19.8 – 3.9 ∼ 5.4 28.8 ∼ 52.0 32.7 ∼ 57.4
Chow et al. [40] No 12.8 ∼ 22.2 – 9.9 ∼ 10.2 45–48 54.9 ∼ 58.2
Ji et al. [41] No 9.3 ∼ 21.2 – 9.4 ∼ 10.3 34.7 ∼ 56.9 40.6 ∼ 63.1
Fudholi et al. [37] No – 800 13.8 54.6 68.4
Chow et al. [37] Yes 8.3 ∼ 12.8 – 8.56 38.9 47.46
Corbin and Zhai [24] Yes – 1000 a 15.9 19 34.9
Anderson et al. [23] Yes Daily average – 12.5–14 40–60 b –
Kim et al. [38] Yes Daily average – ∼17 ∼30 ∼47
Ibrahim et al. [34] Yes – 690 10.4–11.3 45–51 55–62
Present BIPVT Yes – 620 12.6 67.1 79.7
Present BIPVT Yes – 800 14.5 62.7 77.2
Present BIPVT Yes – 1000 15.8 59.4 75.2
BIPVT, Building integrated photovoltaic/thermal; CFD, computational fluid dynamics.
a Experimentally validated CFD simulation.
b A packing factor of 40% was applied to the collector.

validated computational fluid dynamics simulation. Their reported results showed that
their BIPVT roof collector was able to provide thermal and combined (thermal plus
electrical) efficiencies of 19% and 34.9%, respectively. Anderson et al. [23] designed a
prototype BIPVT water collector that was integrated into the standing seam or toughed
sheet roof. In calculating the thermal efficiency, a packing factor of 40% was applied,
while the electrical efficiency was calculated by an indirect method which included an
−1
electrical efficiency loss factor of 0.5% (°C) . Their results showed that the thermal and
electric efficiencies of the BIPVT roof collector were within the ranges of 12.5% ∼ 14%
and 40% ∼ 60%, respectively. Kim et al. [38] developed a water-type unglazed BIPVT col-
lector. Based on expressions similar to eqs. (14.2) and (14.4) in this study, the thermal
and electrical efficiencies of their BIPVT under a clear day from 9:00 am to 3:00 pm were
calculated, respectively. It was reported that the average thermal and electrical efficien-
cies were 30% and 17%, respectively.
Based on the spiral flow absorber designed in reference [36], Ibrahim et al. [34]
developed a BIPVT roof system with the spiral flow copper absorber attached to the
bottom of PV modules on the roof. The collector was a flat plate with single glazing
sheet. The thermal performance of the PVT unit was evaluated by the Hottel–Whillier
equations while the electrical efficiency was calculated by the indirect method with
an electrical efficiency loss factor of 0.45% (°C) . From the energy analysis for a mass
−1
−2
−1
flow rate of 0.027 kg s and an average solar radiation of 690 W m , it was found that
the average electric and thermal efficiencies of the BIPVT roof were 10.8% and 48%,
respectively.