This study presents the test results of our variable aperture mechanism which allows a solar reactor to dynamically respond to the changes in incoming solar radiation. Virtual prototyping was used to check the control system implemented, while experimental testing helped us to identify the drawbacks of the mechanism and the loop holes in the control system. A comparison of variable aperture verses fixed aperture is given to show the benefits of this mechanism. Numerical methods such as Euler and the trapezoidal rule were used in modeling. Tests results show that varying aperture size saves 2.2% energy during a cloudy day and 0.3% on a sunny day. The results from these experiments have also shown that there is a slight deviation of the aperture blades from their required position (by ±0.5 mm to ±1 mm). But overall, the combination of the control system and the selected hardware along with the aperture assembly responded to the changes successfully. The results of our experimental findings and theoretical calculations showed that this variable aperture concept is able to provide more stable internal temperature inside a solar reactor compared to fixed aperture concepts.