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ABSTRACT
The aim study in the solar air collector is a focus on the matter of the deficiency of the thermal transfer between the fluid and the absorber plate, so we built a thermal solar flat plate collector and made some adjustments. The collector was built in the hall of Department of Mechanical Engineering based in the University of Biskra, by considering to minimize the thermal losses to the minimum and increasing the difference between the inlet and the outlet temperatures (thermal efficiency) by adding a rectangular baffles perpendicular to the air stream. The experiment was divided into different modes. Each mode has its own specific number and placement of baffles. This article represents the results that were taken from the experimental study, which shows the increase in the thermal efficiency by a significant value. We also present the effects of other variations on the thermal efficiency itself. It has also been found that thermal efficiency with median and all placement transversal baffle of solar air heater is greater than another mode, using same air flow rate and number of baffles. Finally, the pressure drop associated with increasing number of baffles and air flow rate was deliberated.
Nomenclature
| ΔP | = | Pressure drop (Pa) |
| A | = | Area of the collector (m2) |
| Cp | = | Specific heat of the air (W/kg/K) |
| G | = | Global solar radiation (W/m2) |
| hw | = | Heat transfer coefficients (W/m2/K) |
| M | = | Flow mass rate (kg/sec) |
| Qu | = | Useful heat collected (W/m) |
| Re | = | Reynolds number |
| S | = | Area of stream channel (m2) |
| Tab | = | Temperature an absorber plate (°C) |
| Tin | = | Inlet temperature (°C) |
| Tout | = | Outlet temperature (°C) |
| TST | = | True solar time (hr) |
| Vf | = | Velocity of air (m/sec) |
| Vwind | = | Wind velocity (m/sec) |
| ΔT | = | Different temperature (K) |
Greek symbols
| Η | = | Collector thermal efficiency (%) |
| Ε | = | Emissivity of an absorber plate |
| Λ | = | Pressure drop coefficient |
| Α | = | Galvanized steel absorber |
| Τ | = | transmission coefficient |