Page 155 - IJES Special Issues for AIEC2016

International Journal of Environment and Sustainability, 2016, 5(1): 54-60 55
Problems such as low PV efficiency, architectural
uniformity, and limited space on the roof for the
installation of the separate system have become
important factors that influenced the idea of
combining the PV/T system into one complete
system. One of the major disadvantages of PV
cell, besides the high cost, is the problem with
low efficiency (Sok et al., 2010). Research in this configuration is the spiral flow design with a
field was carried out in the mid-1970s to early
1980s. The earliest study on the PV/T water
collector was performed by Florschuetz (1979)
who extended the Hottel and Whillier (1955) to
analyze the combination of PV/T flat plate
collector. As mentioned by Zondag et al. (2002),
combining the PV/T collector will provide
solutions to problems such as PV efficiency
increasing due to the cooling effect, provide
more architectural uniformity by aesthetic
design, and finally, minimize the usage of space
on the roof. These will reduce the payback
period.
2. Previous Research
Wolf (1976) first investigated flat plate PV/T
fluid systems and dissected the effect of the mix
of heating and PV power systems for homes. He
concluded that the system is feasible and cost
effective. The Hottel–Whillier model is utilized to analysis of the PV/T collector. The phenomenon
use the mix of PV and thermal flat plate collectors under consideration was governed by the steady
with the conventional hot water system and PV
panel to minimize establishment usage.(Hottel
and Whillier, 1958).
Zondag et al. (2001) and Jong (2001) have con-
ducted a series of comparisons between dif-
ferent types of PV/T design and different types
of thermal systems. Their experiments generally
investigated the covered and uncovered PV/T
and thermal systems. Their studies indicated
that an uncovered PV/T shows improved effi-
ciency with the use of PV/T for low-temperature
ground storage integrated with a heat pump.
Zondag (2008) reviewed various concepts of
combined PV-thermal collector technologies by
introducing and evaluating nine different de-
signs, ranging from the complicated to the
simple, in order to investigate the maximum
yield. They concluded that the design of the
channel below the transparent PV, with its PV-
on-sheet and tubes design, gives the best effi-
ciency overall.
Performance simulation of PV/T collectors with
seven new design configurations of absorber
collectors design has been studied by Ibrahim et
al. (2009) and conclude that the best design
thermal efficiency of 50.12% and cell efficiency
of 11.98%.
PV/T collectors have been recently utilized in
different industries, and such collector moti-
vated researchers in different fields of study
perform experimental and numerical methods
(Al-Shamani et al., 2015; Al-Shamani et al., 2014;
Bergene and Løvvik, 1995; Chow, 2003; Coven-
try, 2005; Cox and Raghuraman, 1985; Huang et
al., 2011; Kadhim et al., 2013; Mbewe et al., 1985;
Skoplaki and Palyvos, 2009; Takashima et al.,
1994; Tripanagnostopoulos, 2007).
3. Methodology
3.1 Governing Equations
The governing equations (continuity, momen-
tum, and energy) must be set to complete CFD
3D computational domain of the continuity,
time-averaged incompressible Navier–Stokes
equations, and energy equation. In the Cartesian
tensor system, these equations could be written
as (Eiamsa-ard and Promvonge, 2008).
3.2 Energy Analysis of PV/T Collector
PV efficiency decreases when the temperature of
the cells increases. The efficiency of the photo-
voltaic cells depends on temperature (Duffie and
Beckman, 1991). Further, the performance of
PV/T collectors can be depicted by the combina-
tion of efficiency expression. It is comprised of
the thermal efficiency th and the PV efficiency
el, which usually includes the ratio of the useful
thermal gain and electrical gain of the system to
the incident of solar irradiance on the collector’s
gap within a specific time or period. As shown in
Equation1, the total efficiency of  overall is used
to evaluate the overall performance of the
system (Duffie and Beckman, 1991).
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