The errors between the experimental and calculated data values of efficiencies were verified by using the mathematical model of Eq.3.

The constants applicable to the Eq.3, were determined by using the computer Fortran

program. The numerical values of parameters are shown in Table.4.

The solar collector efficiency results show that there is an average deviation of 2.90% between the calculated and the experimental data. The mathematical model (Eq.3) validate the experimental results with minimum deviation of 0.14% at Vs=30m3/h/m2 and maximum deviation of 11.2% at Vs=20m3/h/m2 from the experimental data for all wind speeds.

Fig. 4. Relationship between collector efficiency and collector airflow at various wind speeds (experimental and calculated data).

5. Conclusion

The purpose of this indoor experimental work was to find evidence of the effect of changes in wind speed and suction velocity on the performance of an unglazed transpired solar collector. Our observations indicate that the peak collector efficiency occurs at zero-wind speed and low efficiencies occur between 1.6m/sec and 3.1m/sec wind speeds. The suction velocities and efficiencies result comparison show that, increasing suction velocities was results in an increases in efficiency. This is the support for our indoor experimental results that wind speeds and fluctuation in suction velocities has a strong influence on collector performance. We remain confident in our conclusions about the effects of wind speed on this system. It seems logical that wind speed is a dominant factor for affecting the efficiency of solar air heating collector. Our current efforts are directed towards finding a multivariable correlation, or model, to explain the indoor scatter experiment measurements. The experimental data were compared with the data obtained by the model. Satisfactory qualitative and quantitative
agreement was obtained between calculated and experimental data. The mathematical model could be deemed to be satisfactory for predicting the efficiency of the perforated solar collector at various wind speeds and suction velocities.

For further applications of the unglazed perforated solar air heating collector, we plan to build the solar wall system to avoid uncontrolled entry of outdoor air into offices and other working areas which is a cause of increased the heating costs.