Civil Engineering Reference
In-Depth Information
collector produces better performance than the single-pass module at a normal
operational mass flow rate range. In addition, the thermal and combined thermal
and electrical efficiencies increased when the packing factor (defined as the ratio of
the PV cell area to absorber area) decreased, whereas the electrical efficiency of
the PVs decreased slightly.
Sandnes and Rekstad (
2002
) constructed a PV/T unit by using a polymer solar
heat collector combined with single-crystal silicon PV cell. An analytical model
derived from the Hottel-Whillier (
1958
) equations was used to simulate the
temperature distribution and the performance of both the thermal and photovoltaic
parts. The simulation results were in agreement with the experimental data. They
found that pasting solar cells onto the absorbing surface would reduce the solar
energy absorbed by the panel (about 10 % of incident energy) due to lower optical
absorption in the solar cells compared to the black absorber plate. Further, there is
an increased heat transfer resistance at the surface of absorber and within the fluid
which reduces the collector's heat-removal factor, F
R
. Moreover, they concluded
that the solar cells' temperature is strongly related to the system (inlet fluid)'s
temperature and also to the collectors' heat transport characteristics. The combined
PV/T concept should therefore be associated with applications of sufficiently low
temperature to give the desired cooling effect.
Tiwari and Sodha (
2006
) developed a thermal model for an integrated photo-
voltaic and thermal solar collector system and compared it with the model for a
conventional solar water heater by Huang et al. (
2001
). Based on energy balance
of each component of the system, an analytical expression for the temperature of
PV module and the water has been derived. The simulations predicted a daily
primary-energy-saving efficiency of about 58 %, which was in good agreement
with the experimental value (61.3 %) obtained by Huang et al. (
2001
).
Dubey et al. (
2009
) developed an analytical model that indicated the electrical
efficiency of PV module with and without cooling flow as a function of climatic
and PV's physical/operational parameters. The four different PV configurations,
i.e. case A (glass to glass-type PV module with duct), case B (glass to glass-type
PV module without duct), case C (glass to tedlar PV module with duct), case D
(glass to tedlar PV module without duct), were investigated. It was found that the
glass to glass-type PV modules with duct give higher electrical efficiency and the
higher outlet air temperature among the all four cases. The annual average effi-
ciency of glass to glass-type PV module with and without duct was reported 10.41
and 9.75 %, respectively.
Chow (
2003
) developed an explicit dynamic model with seven nodes of a
single-glazed flat-plate water-heating PV/T collector suitable for use in systems'
dynamic simulation. This model, derived from the control-volume finite-difference
formulation and incorporated with a transport relay subprogram, could provide
information on transient performance, including the instantaneous thermal/elec-
trical gains, their efficiencies and thermal conditions of various components.
Further to an extension of the nodal scheme to include multidimensional thermal
conduction on PV and absorber plates, this model was able to perform complete
energy analysis on the hybrid collector.
