# L2 questions | Mechanical Engineering homework help

All answers must have 5-7 sentences each, must be in own words

1. What is solar radiation? Explain with help of plank’s energy distribution (spectrum) diagram.

2. How do you calculate total irradiance from the sun?

3. Explain Stefan-Boltzmann law, Weins displacement law, and inverse square law.

4. Calculate total energy emitted by sun. (find energy emitted per unit area using S-B law, then multiply that with surface area of sun)_

5. Calculate total energy emitted by earth.

6. What is solar irradiance and what is its value on the surface of the earth.

7. Explain a) scattering b) absorption and c) reflection of solar radiation

8. Explain the phenomena selective absorption in the atmosphere.

9. Explain the terms a) irradiation b) radiosity c) Insolation d) solar constant

10. Explain summer and winter solstice

11. Explain monthly insolation at different latitudes on the surface.

12. What is solar altitude angle and azimuth angle?

13. What is daily insolation and how do you calculate it. What are factor influencing it?

14. Explain with a diagram the ‘physics’ behind a flat solar collector.

15. How do you calculate energy absorbed and lost by a receiver of flat plate collector.

16. Explain specular, diffuse and general deflection of light.

17. How do you calculate energy ultimately absorbed in a flat plate collector.

18. What is Heat removal factor

19. How do you calculate efficiency of a flat plat collector?

20. For a flat plate collector if the transmittity, absorptivity and reflectivity are respectively 0.7, 0.8 and 0.7 respectively. Calculate the fraction of solar energy ultimately absorbed.

21. The flat plate collector in Q20 has area 20 m2. Solar radiation intensity available to the plate is 200W/m2. Calculate the amount of radiation absorbed by the plate.

22. For the same collector, if the surface temperature is 80oC and ambient temperature is 25oC. The overall heat transfer co-efficient is 15W/m2oC. Calculate the heat loss to surrounding from the collector

23. Calculate energy utilized by the absorber

24. Water is used to remove heat from the collector. The temperature of fluid at inlet and out let of the collector is 20 and 89oC respectively. Calculate the mass flow rate required.

25. Calculate the heat removal factor for the collector

26. Calculate collector efficiency