Podcast
Questions and Answers
What is the name of the layer where energy is transferred to the photosphere?
What is the name of the layer where energy is transferred to the photosphere?
What is the primary source of energy for life on Earth?
What is the primary source of energy for life on Earth?
Solar energy is a non-renewable source of energy.
Solar energy is a non-renewable source of energy.
False
What is the name of the outermost layer of the Sun?
What is the name of the outermost layer of the Sun?
Signup and view all the answers
What is the primary element in the Sun by volume?
What is the primary element in the Sun by volume?
Signup and view all the answers
What is the name of the process by which the Sun produces energy?
What is the name of the process by which the Sun produces energy?
Signup and view all the answers
What is the average distance between the Earth and the Sun?
What is the average distance between the Earth and the Sun?
Signup and view all the answers
The Earth's orbit around the Sun is perfectly circular.
The Earth's orbit around the Sun is perfectly circular.
Signup and view all the answers
What is the name of the point in the Earth's orbit where it is closest to the Sun?
What is the name of the point in the Earth's orbit where it is closest to the Sun?
Signup and view all the answers
What time of year does the Sun reach its highest position in the sky in the Northern Hemisphere?
What time of year does the Sun reach its highest position in the sky in the Northern Hemisphere?
Signup and view all the answers
The Earth's rotation on its axis takes approximately 23 hours and 56 minutes.
The Earth's rotation on its axis takes approximately 23 hours and 56 minutes.
Signup and view all the answers
Which of the following is NOT a factor that affects the amount of solar radiation received at a location on Earth?
Which of the following is NOT a factor that affects the amount of solar radiation received at a location on Earth?
Signup and view all the answers
Which of the following is considered a primary objective in the positioning of solar collectors?
Which of the following is considered a primary objective in the positioning of solar collectors?
Signup and view all the answers
What is the name of the optical instrument used for measuring azimuthal and zenith angles?
What is the name of the optical instrument used for measuring azimuthal and zenith angles?
Signup and view all the answers
What is the name of the standard that defines methods for calculating solar irradiance on inclined surfaces?
What is the name of the standard that defines methods for calculating solar irradiance on inclined surfaces?
Signup and view all the answers
What is the term used to describe the ratio of global radiation to diffuse radiation?
What is the term used to describe the ratio of global radiation to diffuse radiation?
Signup and view all the answers
What is the name of the instrument used to measure global solar irradiance on a horizontal plane?
What is the name of the instrument used to measure global solar irradiance on a horizontal plane?
Signup and view all the answers
What is the name of the device used to measure direct solar irradiance?
What is the name of the device used to measure direct solar irradiance?
Signup and view all the answers
The quality of a pyranometer is determined by its sensitivity to temperature changes.
The quality of a pyranometer is determined by its sensitivity to temperature changes.
Signup and view all the answers
Which type of pyranometer uses black and white surfaces to measure solar radiation?
Which type of pyranometer uses black and white surfaces to measure solar radiation?
Signup and view all the answers
Photodiode pyranometers are highly accurate for measuring DHI in clear sky conditions.
Photodiode pyranometers are highly accurate for measuring DHI in clear sky conditions.
Signup and view all the answers
Solar trackers are used to follow the apparent movement of the Sun across the sky.
Solar trackers are used to follow the apparent movement of the Sun across the sky.
Signup and view all the answers
What is the name of the system used to shade a pyranometer from direct sunlight when measuring DHI?
What is the name of the system used to shade a pyranometer from direct sunlight when measuring DHI?
Signup and view all the answers
Which of the following is a graphical representation of the apparent path of the Sun across the sky?
Which of the following is a graphical representation of the apparent path of the Sun across the sky?
Signup and view all the answers
The sun path diagram usually represents the Sun's path over a period of one month.
The sun path diagram usually represents the Sun's path over a period of one month.
Signup and view all the answers
What is the term referring to the ratio of irradiance on an inclined surface to that on a horizontal surface?
What is the term referring to the ratio of irradiance on an inclined surface to that on a horizontal surface?
Signup and view all the answers
What is the name of the standard that provides information on the energy performance of buildings, including external climatic conditions and conversion of climatic data for energy calculations?
What is the name of the standard that provides information on the energy performance of buildings, including external climatic conditions and conversion of climatic data for energy calculations?
Signup and view all the answers
When analyzing hourly solar radiation on an inclined surface, the reflected radiation from the ground is always considered negligible.
When analyzing hourly solar radiation on an inclined surface, the reflected radiation from the ground is always considered negligible.
Signup and view all the answers
What is the primary factor that distinguishes the anisotropic sky model from the isotropic sky model in calculating hourly solar radiation?
What is the primary factor that distinguishes the anisotropic sky model from the isotropic sky model in calculating hourly solar radiation?
Signup and view all the answers
Which of the following models is widely used for calculating hourly solar radiation on an inclined surface, taking into account the anisotropy of the sky?
Which of the following models is widely used for calculating hourly solar radiation on an inclined surface, taking into account the anisotropy of the sky?
Signup and view all the answers
Concentrating solar collectors are only viable for areas with high levels of solar irradiance.
Concentrating solar collectors are only viable for areas with high levels of solar irradiance.
Signup and view all the answers
The maximum concentration ratio of a cylindrical parabolic concentrator is generally higher than that of a spherical parabolic concentrator.
The maximum concentration ratio of a cylindrical parabolic concentrator is generally higher than that of a spherical parabolic concentrator.
Signup and view all the answers
What is the primary function of a solar tracker in a concentrating solar collector system?
What is the primary function of a solar tracker in a concentrating solar collector system?
Signup and view all the answers
The angle of appearance of the sun on a surface is always the same as the angle of disappearance, implying a symmetric path of the Sun across the sky.
The angle of appearance of the sun on a surface is always the same as the angle of disappearance, implying a symmetric path of the Sun across the sky.
Signup and view all the answers
Which of the following is a method of calculating the daily irradiation incident on an inclined surface facing south?
Which of the following is a method of calculating the daily irradiation incident on an inclined surface facing south?
Signup and view all the answers
The ratio of daily radiation incident on a south-facing inclined surface to the horizontal surface is commonly referred to as the 'Rb' factor.
The ratio of daily radiation incident on a south-facing inclined surface to the horizontal surface is commonly referred to as the 'Rb' factor.
Signup and view all the answers
When calculating the annual irradiation on an inclined surface, the simplified approach assumes that the monthly average daily irradiation is equal to the daily irradiation on the representative average day of each month.
When calculating the annual irradiation on an inclined surface, the simplified approach assumes that the monthly average daily irradiation is equal to the daily irradiation on the representative average day of each month.
Signup and view all the answers
Which of the following Italian standards provides guidelines for calculating and distributing solar irradiance into direct and diffuse components on inclined surfaces?
Which of the following Italian standards provides guidelines for calculating and distributing solar irradiance into direct and diffuse components on inclined surfaces?
Signup and view all the answers
The EN ISO 52010-1 standard is solely focused on solar radiation data and does not have any provisions for other climate-related data.
The EN ISO 52010-1 standard is solely focused on solar radiation data and does not have any provisions for other climate-related data.
Signup and view all the answers
Study Notes
Solar Radiation Part 1
- Sun's Structure:
- Chromosphere, Photosphere, Convective Zone, Radiative Zone, Core, Sunspots
- Corona (outer layer)
- Hydrogen and Helium (primary elements)
- Solar Radiation Facts:
- Sun produces energy through nuclear fusion (4H → He + 2e + 2y + E)
- The Earth receives significantly more energy in less than one hour than human consumption in a whole year.
- The solar constant is 1367 (W m⁻²)
- 92.1% hydrogen, 7.8% helium.
- Earth-Sun Distance:
- 1.496 x 10¹¹m = 149.6 million km
- ±1.7% variation in distance
Solar Energy: Main Advantages
- Primary source of energy on Earth
- Inexhaustible resource
- Abundant supply across the planet
Solar Energy: Disadvantages
- Variable supply throughout the day and year
- Low power density
- Expensive technologies required to harness it
- Non-standard design considerations (location specific)
Sun Structure
- Core: High temperature (16 million K), High density (160 g/cm³)
- Radiative Zone: Energy transport via radiation
- Convective Zone: Energy transport via convection
- Photosphere: “Surface of the Sun”
- Chromosphere: Above the Photosphere
- Corona: Outermost part of the Sun, Very Hot
Elements in The Sun
- Element | % Volume | % Mass
- Hydrogen | 92,100 | 73.46
- Helium | 7,800 | 24.85
- Oxygen | 0.061 | 0.77
- Carbon | 0.030 | 0.29
- Other (N,Ne,Fe,Si,Mg,S) | 0.0015 - 0.0084 | 0.06-0.16
Earth Motions
- Earth rotates on its axis, one rotation taking 24 hours.
- Earth orbits the Sun, taking nearly one year for one revolution.
- Earth's axis tilt (23.5°) causes the seasons.
Earth-Sun Distance
- Average distance: 1.496 x 10¹¹ m
- Earth's orbit is elliptical, causing distance variation.
- Ratio (average distance / distance on any given day) is calculated using the following formula r = 1 + 0.033 cos (360n/365)
Earth-Sun Variables
- The solar constant is 1367 W/m²
- The earth's orbit eccentricity causes a variation in the distance between the sun and the earth.
- The variation on distance is around 3.3%
Nuclear Fusion Reaction
- The sun's core generates energy through nuclear fusion.
- 600 million metric tons of hydrogen are converted to helium each second.
- Significant amount of energy is released.
Radiation Crossing The Atmosphere
- Various substances absorb and scatter solar radiation.
- Ozone (O3) absorbs between 0.15 and 0.4 μm.
- Water vapor (H2O) absorbs between 0.8 and 2 μm.
- Carbon dioxide (CO2) absorbs between 2.5 and 4.5 μm.
- Types of dispersion: Rayleigh Scattering, Mie Scattering, Reflection
Air Mass
- Air mass (AM) is a measure of the amount of atmosphere traversed by solar radiation.
- Calculated using the following equation AM = 1 / cos z / sin (h)
Solar Constant
- Standard value: 1367 W/m²
- Represents solar power per square meter normal to solar rays, outside atmosphere, atmean earth-sun distance.
Global Emissive Power
- Total solar power radiated by the Sun, approximately 3.826 x 10²⁶ W
- Flux received by the Earth is calculated based on average solar irradiance
Uptake of Direct and Diffuse Radiation
- Direct radiation comes in straight lines from the sun.
- Diffuse radiation comes from dispersed light in the sky.
- The percentage of diffuse light varies depending on atmospheric conditions.
Solar Radiation Spectrum
- The solar spectrum is the distribution of solar energy across different wavelengths (nm).
- The spectrum varies between UV and infrared radiation.
- Different atmospheric components absorb light at specific wavelengths.
Measuring Solar Radiation
- Pyrheliometers measure direct normal irradiance (DNI).
- Pyranometers measure global irradiance (GHI).
- Solar trackers follow the sun's movement for accurate measurements.
Pyranometer classification
- Pyrheliometers and Pyranometers are instruments whose objective is to measure the solar radiation.
- Classification criteria, for example, response time, spectral sensitivity and zero offset.
- Criteria of classification: response time, zero offset, stability, resolution, and non-linearity.
Solar Spectrum (extraterrestrial and AM = 1)
- Shows how much solar energy is at each wavelength and how atmospheric components impact that energy.
- extraterrestrial radiation is used as a base to compare the effects of the atmosphere with varying air masses.
Horizontal Plane Irradiation:
- Daily average of horizontal global (GHI) and diffuse horizontal irradiance (DHI)
- Typical values can be obtained from weather data.
- Measurement methods are used to record these quantities.
Sun's Position
- Declination (δ) : Angle between the Earth's equatorial plane and the line connecting the center of the Earth to the center of the sun.
- Hour Angle (ω) : Angle made between the local meridian and the plane of the sun.
Sun Path
- Calculating sun's path on a surface (apparent position of the sun in the sky).
- Includes factors such as the time of day, time of year, and latitude.
- The sun's path is affected by the Earth's rotation and its orbital path around the sun.
Concentrating Collectors
- Different designs used to concentrate solar radiation.
- Configurations vary: tubular, parabolic, Fresnel, heliostat
- Used in applications where high temperature is needed.
- High concentration ratios lead to high temperatures.
Yearly Global Irradiation
- Data represents the amount of solar energy received on a horizontal surface over a period of one year.
- Geographic locations with higher numbers represent areas that receive more solar energy per year.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the fascinating structure of the Sun, including its various layers and the nuclear fusion process that powers it. This quiz also covers the benefits and drawbacks of solar energy as a resource for Earth. Test your knowledge of solar energy's advantages, disadvantages, and relevant facts!
