Solar Angles

Question 1

Solar radiation

Answer 1

The radiation or energy rate we get fromthe sun. Measured by W or kw

Question 2

Solar irradiance

Answer 2

The intensity of solar energy or radiation on square meter. Measured in kw/m2 or u/m2

Question 3

Solar irradiation (insolation)

Answer 3

The total amount of solar radiation energy received on given surface area during a given time. Measured in wh/M2/day

Question 4

Declination angle

Answer 4

The angular position of the sun at solar noon with respect to the plane of the equator north positive - 23.45 < dec angle <23.45

Question 5

Latitude and le

Answer 5

The angular location north or south of the equator, north positive -90 < angle <90

Question 6

Hour angle

Answer 6

The angular displacement of the sun east or west of local meridian due to rotation of earth on its axis 15° per hour - morning-ve, afternoon positive

Question 7

Tilt angle (slope)

Answer 7

The angle between the plane of the surface in question and the horizontal - o angle <180
Angle 790 means the surface has a downward-facing component.
Tilt angle increases in winter and Dec in summer

Question 8

Surface azimuthangle

Answer 8

The deviation of the projection on a horizontalplane of the normal surface from the local Meridan, zero due south, east negative, west positive - 180 < angle < 180 recommended to design at zero.

Question 9

Angle of incidence

Answer 9

The angle between the beam radiation on the surface and the normal to the surface

Question 10

Zenith angle

Answer 10

The angle between the vertical und the line to the sun, that is the angle of incidence of beam radiation on horizontal surface

Question 11

Elevation angle (Solar altitude)

Answer 11

The angle between the horizontal and the line to the sun sits complement of zenith angle.

Question 12

Solar azimuth

Answer 12

The angular displacement from south of the projection of beam radiation on the horizontal plane, displacements east of south are negative, west of south are positive

Question 13

Standard test conditions

Answer 13

Temperature 25° -cell temp
Irradiance: 1000 w/ m2
Air mass 1.5
PV panel at STC operate with Max eff.

Question 14

Air mass

Answer 14

The influence of theatmosphere depends on the length of path through the atmosphere.

Question 15

Spacing

Answer 15

The min required space between PV panels its calculated in the worst case scenario of shading, 12 PM in 21st of December.

Question 16

Peak sun hours

Answer 16

Total amount of solar radiation received by a given location over the source of a day that reaches an average of 1000 W/ m2