Tutorial – Solar Geometry – 1
1. If the distance between the Sun and Earth is L = 1.496 × 1011 m and D = 1.393 × 109 m.
Determine the solar constant. Take the effective surface temperature of the sun as Tsun=
5778 K and σ = 5.67 * 10-8 W/m2 K4
Ans.: 1370 W/m2
2. If the distance between the sun and the earth was the half of what it is, what would the
solar constant be? The sun is a nearly spherical body that has a diameter of D = 1.393 ×
109 m and the effective surface temperature of the sun is Tsun = 5778 K.
Ans: 5479.42 W/m2
3. Find out the day when the declination angle will be -23.45º?
Ans.: 21st December
4. Calculate the zenith angle of the Sun at New Delhi (28º35’) at 2:30 pm on 20th February,
1995.
Ans.: 54.03º
5. Calculate the number of daylight hours (sunshine hour) for the above-mentioned data in
question no. 4.
Ans.: 12.84 hours
6. A solar panel is mounted facing due south in a location at 48° north latitudes, with a tilt
angle of 30°. If the sun shines on the panel for the entire day on the equinox with clear
skies. Calculate the total energy incident per square meter on the panel during the course
of the day in kWh.
Ans.: 18º
7. A house at 42° north latitude has a roof that faces due south and is elevated to an angle of
23°. A solar panel is mounted to the roof. What is the angle of incidence between the sun
and the array at 10 a.m. on May 5th?
Ans.: 28.7º