european journal of social sciences issn: 1450-2267 - EuroJournals
european journal of social sciences issn: 1450-2267 - EuroJournals
european journal of social sciences issn: 1450-2267 - EuroJournals
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European Journal <strong>of</strong> Social Sciences – Volume 5, Number 3 (2007)<br />
However, high incident will increase the temperature <strong>of</strong> the solar cells and that will decrease the<br />
efficiency <strong>of</strong> the panel.<br />
Therefore, to achieve both higher cell efficiency and higher electrical output we must cool the<br />
PV cells. To eliminate an external electrical source from the thermal system and to cool the PV cells in<br />
photovoltaic system we integrate a photovoltaic panel with solar air/water heater collector, this can<br />
make when photovoltaic cells pasted directly on the flat plate absorber. This type <strong>of</strong> system is called<br />
photovoltaic thermal collector (PV/T) or hybrid (PV/T).<br />
A number <strong>of</strong> theoretical as well as experimental studies have been made on PV/T systems with<br />
air and liquid as working fluid. Kern and Russell (1978) are the first who give main concept <strong>of</strong> PV/T<br />
collector using water or air as the heat removal fluid (working fluid). Chandra (1983) have analysis<br />
theoretically two different configuration single and double pass photovoltaic air heaters and they have<br />
shows that the double pass are more efficiency than single pass collector. Cox and Raghuraman (1985)<br />
study air type PV/T system by analysis the effects <strong>of</strong> various design variables on the performance <strong>of</strong><br />
the system. Bharagava et al. (1991) and Prakash (1994) reported the effect <strong>of</strong> air mass flow rate, air<br />
channel depth, and packing factor. Sopain et al. (1995) have successfully demonstrated the improved<br />
performance <strong>of</strong> steady state double pass collector over the single pass collector due to efficient cooling<br />
<strong>of</strong> pv cells. Sopian et al. (2000) developed and tested a double pass photovoltaic collector suitable for<br />
solar drying applications and they comparison between theoretical and experimental results.<br />
Tripanagnotopoulos et al. (2002) built and tested various photovoltaic thermal collector models with<br />
both water and air as the working fluids. Y. B. Assoa (2007) developed simplified steady state 1-D<br />
mathematical model <strong>of</strong> (pv/t) bi-fluid (air and water) collector with a metal absorber. A Parametric<br />
study (numerically and experimentally) to determine the effect <strong>of</strong> various factors such as the water<br />
mass flow rate and thermal performance was studied. Simulation results were compared with the<br />
experimental results. Othman et al (2007) investigate the performance <strong>of</strong> double pass (pv/t) air heater<br />
with fins fixed in the bottom <strong>of</strong> absorber, the system theoretically under steady state conditions and<br />
experimentally was studied. They conclude that it is important to use fins as integral part <strong>of</strong> the<br />
absorber surface in order to achieve meaningful efficiencies for both thermal and electrical output <strong>of</strong><br />
photovoltaic solar collector.<br />
In this work an experimental study <strong>of</strong> prototype single pass with both sides <strong>of</strong> the absorber<br />
photovoltaic thermal PV/T solar collector with and without CPC and fins was studied. The PV/T was<br />
test experimentally to determine its photovoltaic, thermal and combined photovoltaic thermal<br />
performance over range <strong>of</strong> operating conditions for both collectors and their results was compared, the<br />
results was discussed<br />
Experimental Setup<br />
The solar collectors considered in this study have three essential static components: a glazing on the<br />
top, a plate containing numerous solar cells and a bottom plate. The schematic diagram <strong>of</strong> the two<br />
experimental setup is shown in Figure 1(a) and figure 1(b) respectively. The size <strong>of</strong> the collector is<br />
0.755 m wide and 1.22 m long, the high <strong>of</strong> the upper channel is 0.165 m and the lower channel is 0.125<br />
m. the total area covered by solar cells is 0.38 m 2 . The air enters through the upper channel formed by<br />
the glass cover and photovoltaic plate and through the lower channel formed by absorber plate with<br />
fins and the back plate at the same time. CPC with concentration ratio (CR) <strong>of</strong> 1.86 is used as a<br />
reflector and located parallel to the air flow in first collector. Rectangular fins attached on the back <strong>of</strong><br />
the photovoltaic panel increase the heat transfer to the air and enhance the efficiency <strong>of</strong> the system in<br />
both collectors. 23 tungsten halogen lamps each rated at 500W used to simulate solar radiation during<br />
the test. The intensity <strong>of</strong> the incoming solar radiation was measured by Eppley pyranometer. Ambient<br />
temperature and other temperatures such as (inlet, outlet, absorber, glass cover, and back plate) at<br />
several positions <strong>of</strong> the system were measured by k – type thermocouple. The air flow sensing element<br />
was <strong>of</strong> the van type probe head and connected direct to the data logger.<br />
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