SE Engr. Solar Resource Assessment and Meteorology 2 — Questions and Answers
Question 1: What does a Typical Meteorological Year (TMY) dataset represent?
- The worst-case solar resource year on record
- A synthetic year of hourly data representing average long-term conditions (Correct answer)
- The average irradiance values across all years in a dataset
- Only satellite-derived data for a single calendar year
Correct answer: A synthetic year of hourly data representing average long-term conditions
A TMY is a composite dataset of 12 selected months from different years, chosen to statistically represent the long-term average solar and meteorological conditions at a location.
Question 2: Which irradiance component should be prioritized when designing a concentrating solar power (CSP) system?
- Global Horizontal Irradiance (GHI)
- Diffuse Horizontal Irradiance (DHI)
- Direct Normal Irradiance (DNI) (Correct answer)
- Global Tilted Irradiance (GTI)
Correct answer: Direct Normal Irradiance (DNI)
CSP systems use optical concentrators that can only focus direct beam radiation, so DNI is the critical resource parameter for CSP site selection and energy modeling.
Question 3: At what solar zenith angle does the Optical Air Mass (AM) equal approximately 2?
- 30°
- 45°
- 60° (Correct answer)
- 75°
Correct answer: 60°
Air Mass is approximated as 1/cos(zenith angle); at a zenith angle of 60°, cos(60°) = 0.5, so AM = 1/0.5 = 2.
Question 4: The Linke Turbidity Factor (TL) quantifies which atmospheric characteristic?
- Percentage of cloud cover at a site
- Atmospheric haziness due to aerosols, dust, and water vapor (Correct answer)
- Panel surface soiling losses
- UV-B radiation intensity at ground level
Correct answer: Atmospheric haziness due to aerosols, dust, and water vapor
The Linke Turbidity Factor describes the optical thickness of the atmosphere relative to a clean, dry atmosphere, accounting for aerosols, dust, and water vapor that attenuate solar radiation.
Question 5: Which of the following is a widely used commercial satellite-derived solar resource dataset for global projects?
- Solargis (Correct answer)
- Landsat-8 imagery
- GPS-Met reanalysis
- NEXRAD radar composite
Correct answer: Solargis
Solargis is a leading provider of satellite-derived solar radiation data and is widely used for bankable solar resource assessments globally.
Question 6: What is the primary cause of attenuation of solar radiation as it passes through the Earth's atmosphere?
- Earth's magnetic field deflecting photons
- Absorption and scattering by gases, aerosols, and clouds (Correct answer)
- Gravitational redshift of solar photons
- Ozone layer reflection of visible light
Correct answer: Absorption and scattering by gases, aerosols, and clouds
Solar radiation is attenuated primarily by absorption from gases (O₂, O₃, H₂O, CO₂) and scattering by aerosol particles and cloud droplets as it travels through the atmosphere.
Question 7: The solar altitude angle is defined as the angle between:
- The sun and true north, measured clockwise
- The sun's rays and the horizontal plane at the observer's location (Correct answer)
- The sun and the zenith, measured from the vertical
- The panel surface and the sun's rays
Correct answer: The sun's rays and the horizontal plane at the observer's location
The solar altitude angle (also called solar elevation angle) is the angle between the sun's rays and the horizontal plane, complementary to the solar zenith angle.
SE Engr. Solar Resource Assessment and Meteorology 2
What does a Typical Meteorological Year (TMY) dataset represent?