A student calculates an optimal tilt angle of 45 degrees, for a given location. For this calculation, the student only considered direct beam irradiation and ignored the effects of the atmosphere. Whilst still ignoring clouds, how do you expect the optimal tilt angle will change if you take into account the influence of the atmosphere?
a) The optimal tilt angle will increase. This is due to a higher energy yield, caused by an increased sky view factor.
b) The optimal tilt angle will increase. This is because at lower sun altitudes, the atmosphere absorbs more light compared to higher altitudes.
c) The optimal tilt angle will decrease. This is due to a higher energy yield, caused by an decreased sky view factor.
d) The optimal tilt angle will decrease. This is because at lower sun altitudes, the atmosphere absorbs more light compared to higher altitudes.
d) The optimal tilt angle will decrease. This is because at lower sun altitudes, the atmosphere absorbs more light compared to higher altitudes.
The correct answer is d) The optimal tilt angle will decrease. This is because at lower sun altitudes, the atmosphere absorbs more light compared to higher altitudes.
To understand why this is the case, you need to consider the influence of the atmosphere on the incoming solar radiation. The atmosphere is not completely transparent and has the ability to absorb and scatter sunlight. When the sun is at a lower altitude, the sunlight has to pass through a larger path length in the atmosphere before reaching the surface. This longer path length increases the chances of absorption and scattering, resulting in a decrease in the intensity of direct beam irradiation.
By considering the influence of the atmosphere, the optimal tilt angle would be adjusted to maximize the amount of direct beam irradiation that reaches the surface. Since the atmosphere absorbs more light at lower sun altitudes, a smaller tilt angle would allow for a greater direct beam irradiation to reach the surface, resulting in a higher energy yield.
Therefore, the optimal tilt angle would decrease when taking into account the influence of the atmosphere.
b) The optimal tilt angle will increase. This is because at lower sun altitudes, the atmosphere absorbs more light compared to higher altitudes.
Yes, the closer to straight up, the less air the rays pass through.