european journal of social sciences issn: 1450-2267 - EuroJournals

European Journal of Social Sciences – Volume 5, Number 3 (2007)
However, high incident will increase the temperature of the solar cells and that will decrease the
efficiency of the panel.
Therefore, to achieve both higher cell efficiency and higher electrical output we must cool the
PV cells. To eliminate an external electrical source from the thermal system and to cool the PV cells in
photovoltaic system we integrate a photovoltaic panel with solar air/water heater collector, this can
make when photovoltaic cells pasted directly on the flat plate absorber. This type of system is called
photovoltaic thermal collector (PV/T) or hybrid (PV/T).
A number of theoretical as well as experimental studies have been made on PV/T systems with
air and liquid as working fluid. Kern and Russell (1978) are the first who give main concept of PV/T
collector using water or air as the heat removal fluid (working fluid). Chandra (1983) have analysis
theoretically two different configuration single and double pass photovoltaic air heaters and they have
shows that the double pass are more efficiency than single pass collector. Cox and Raghuraman (1985)
study air type PV/T system by analysis the effects of various design variables on the performance of
the system. Bharagava et al. (1991) and Prakash (1994) reported the effect of air mass flow rate, air
channel depth, and packing factor. Sopain et al. (1995) have successfully demonstrated the improved
performance of steady state double pass collector over the single pass collector due to efficient cooling
of pv cells. Sopian et al. (2000) developed and tested a double pass photovoltaic collector suitable for
solar drying applications and they comparison between theoretical and experimental results.
Tripanagnotopoulos et al. (2002) built and tested various photovoltaic thermal collector models with
both water and air as the working fluids. Y. B. Assoa (2007) developed simplified steady state 1-D
mathematical model of (pv/t) bi-fluid (air and water) collector with a metal absorber. A Parametric
study (numerically and experimentally) to determine the effect of various factors such as the water
mass flow rate and thermal performance was studied. Simulation results were compared with the
experimental results. Othman et al (2007) investigate the performance of double pass (pv/t) air heater
with fins fixed in the bottom of absorber, the system theoretically under steady state conditions and
experimentally was studied. They conclude that it is important to use fins as integral part of the
absorber surface in order to achieve meaningful efficiencies for both thermal and electrical output of
photovoltaic solar collector.
In this work an experimental study of prototype single pass with both sides of the absorber
photovoltaic thermal PV/T solar collector with and without CPC and fins was studied. The PV/T was
test experimentally to determine its photovoltaic, thermal and combined photovoltaic thermal
performance over range of operating conditions for both collectors and their results was compared, the
results was discussed
Experimental Setup
The solar collectors considered in this study have three essential static components: a glazing on the
top, a plate containing numerous solar cells and a bottom plate. The schematic diagram of the two
experimental setup is shown in Figure 1(a) and figure 1(b) respectively. The size of the collector is
0.755 m wide and 1.22 m long, the high of the upper channel is 0.165 m and the lower channel is 0.125
m. the total area covered by solar cells is 0.38 m 2 . The air enters through the upper channel formed by
the glass cover and photovoltaic plate and through the lower channel formed by absorber plate with
fins and the back plate at the same time. CPC with concentration ratio (CR) of 1.86 is used as a
reflector and located parallel to the air flow in first collector. Rectangular fins attached on the back of
the photovoltaic panel increase the heat transfer to the air and enhance the efficiency of the system in
both collectors. 23 tungsten halogen lamps each rated at 500W used to simulate solar radiation during
the test. The intensity of the incoming solar radiation was measured by Eppley pyranometer. Ambient
temperature and other temperatures such as (inlet, outlet, absorber, glass cover, and back plate) at
several positions of the system were measured by k – type thermocouple. The air flow sensing element
was of the van type probe head and connected direct to the data logger.
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