We will study a method to see how a particular natural or artificial object located close to our solar power installation may or may not affect their shadows. For this we will use the map of the solar trajectories in Cartesian coordinates. Let's see how we interpret the axes of the map (right figures):
We can draw on the X axis azimuth, or angle (projected on the floor) that from the position of a hypothetical observer looking south and measured from the polar axis, you see the sun from going out (for each day and month of year) to be hidden. From that position, at right is the West (axis x +) and left the East (axis x-). To the east, the azimuth is measured - and to the west, +, by convention, because the angle is taken positive in the sense of the apparent movement of the Sun At 12 am the sun, the azimuth is 0 °. In the shaft and + we'll represent the solar height in degrees, or angle of elevation is taking the Sun from which we see out (0 °) until it reaches the top (12 am) on the shaft and then decreases such height (negative angle) to be 0 ° at sunset. For each latitude, and each day of the year, we can draw a curve of the solar path and described (a kind of concentric arcs.) In our case the trajectories are shown for the days December 1, 1921 March, May 6 and June 21. If we had represented the December 21, would be under the day 1, and that the paths of major and minor solar height at 12 am, soslticios correspond to summer and winter.
We will choose a particular case, represented in the figure in color, the city of Malaga and in the diagram represent two obstacles located by its azimuth, solar altitude and elevation from the observer's position.
data obstacles are:
- tower 15 m high, with coordinates from the observer looking south from the position of the observer are (x = -6 m, y = 16 m)
- Mound 4 m in elevation, idem. coordinates (x = 5m, y = 10 m)
- For t. Pythagoras, or going to fleece the calculator, I get horizontal separation distance between the observer and the tower, namely: 17.09 m.
- With the distance to the object and the vertical height, calculated by arctang (15/17, 08) and we have the solar height of the object, or angle of elevation from the observer to the top of the roof. Thus we get 41.27 degrees.
- Calculating azimuth of the tower, is made with arctn (6 / 16), giving 20.55 ยบ. As it is located to the east, making the angle negative.
- calculated with the coordinates, the separation between the observer and the mound (the highest peak), obtaining 11.18 m.
- apply arctan (4 / 11, 18) and removed the solar height of 19.68 degrees elevation object.
- azimuth calculation of the mound: Idem. arctan (5 / 10) = 26.56 °. As it is located to the west is taken as positive.
If you look at the sun's path, all of which intersect with the obstacle, will result a shadow over the sun rising or falling as having positive or negative azimuth respectively. The mound, to be under the trajectory of the three days represented, will not produce a shadow on the observer (installation position). The tower is something else. On December 1, cast a shadow on the observer, from sunrise until the sun reaches the height of the object, which happens to -26.55 °.
Alcad
Alcad
0 comments:
Post a Comment