L-13-14_SolarEnergy Final_112a421a-c4ed-4a24-a8a0-1f45359e3e70

Lecture 13: Solar Energy

Introduction

• Course: SEE211 - Energy, Climate Change and Sustainability

• Reference: "Here Comes the Sun" by the Beatles (1969)

Page 1: Overview of the Sun

• Composition: 90% hydrogen (H2), 9% helium (He), and 1% other elements

• Fusion Reaction: 41H + 2e = 4He + 2 neutrinos (ν) + 6 gamma rays (γ)

• Energy Released: ΔE = 26.7 MeV

• Key Parameters:

  • Amount of Energy

  • Spectral and Temporal Distributions

  • Variations Over Time

Page 2: Extraterrestrial Solar Radiation

• Solar Constant (Isc): 1.367 kW/m²

• Formula for Radiant Power Density Outside Earth's Atmosphere:

  • Is = Isc * [1 + 0.033 cos(n)]

  • n: Day of the Year (variation ±3.3% over the year)

Page 3: Importance of Extraterrestrial Solar Radiation

Reasons for Significance:

1. Measurement Consistency:

   • Measured outside Earth's atmosphere, free from atmospheric interference (clouds, dust, gas)

2. Standard Reference:

   • Baseline for understanding solar energy modification by Earth's atmosphere

3. Energy Budget:

   • Essential for understanding energy absorption, reflection, and emission by Earth

• Solar constant value is approximately 1361 watts/m²

Page 4: Solar Irradiance Curve

• Mean extraterrestrial irradiance is ~1.35 kW/m²

• Importance in evaluating solar energy systems

Page 5: Spectral Irradiance Curve

Key Points:

1. Wavelength Range:

   • Spans UV to IR

2. Peak Irradiance:

   • Peaks around 500 nm in visible spectrum

3. Atmospheric Effects:

   • Dips in curves due to absorption by atmospheric gases (ozone, CO2, water vapor)

Page 6: Black Body Spectrum

Importance:

1. Astronomy:

   • Studying star spectra, temperature, and composition

2. Thermodynamics:

   • Foundation for radiation theory in physics

3. Technological Applications:

   • Design in thermal management systems

4. Climate Science:

   • Studying Earth's radiation and greenhouse effect

Page 7: Solar Energy Potential

• Total solar energy reaching Earth: 1.7x10¹⁷ W (170 petawatts)

• Annual solar energy exceeds fossil fuel resources available on Earth

• 1% irradiance with 10% conversion efficiency meets global energy needs

• 2022 Energy Statistics:

  • Solar Flux: 3,850,000 EJ

  • Wind: 2,250 EJ

  • Biomass: 3,000 EJ

  • Electricity: 24,398 TWh (87 EJ)

Page 8: Overview of Solar Radiation

• Components of energy transfer

  • Incoming sunlight absorption, reflection, emission

  • Diagram representation of Earth's energy balance

Page 9: Limitations of Solar Energy

• Discussing inherent challenges in solar energy applications

Page 10: Impact of Precipitation on Solar Power Generation

Key Considerations:

• Geographical Location:

  • High precipitation areas may face more cloud cover

• Seasonal Variations:

  • Planning for seasonal changes in solar power generation

• Hybrid Systems:

  • Utilizing combinations of renewable sources for stability

• Summary: Precipitation impacts efficiency but can be beneficial in cleaning panels.

Page 11: Air Mass and Solar Radiation

Description:

• Path length of sunlight through atmosphere affecting radiation intensity

• Definitions:

  • AM0: Outside atmosphere

  • AM1: Sun at zenith

  • AM1.5: Standard spectrum for most applications

Page 12: Air Mass Impact on Solar Power

Key Effects:

1. Intensity of Solar Radiation:

   • Greater air mass results in lower intensity due to scattering

2. Absorption and Scattering:

   • More atmospheric interference at higher air masses

3. Panel Performance:

   • Understanding air mass is essential for panel orientation and efficiency

Page 13: Spectral Irradiance Graph

Overview:

• Graph showcasing spectral irradiance regarding solar technology performance

Page 14: Solar Resource Map

Indian Context:

• Highlighting solar potential across major cities in India

• 1600 GW potential per km² noted

Page 15: Solar Technologies

Types:

• Active Systems:

  • Utilize photovoltaic panels and thermal collectors

• Passive Systems:

  • Involve building materials and design for natural air circulation

Page 16: Applications of Solar Technologies

Usage:

• Architecture, agriculture, solar lighting, heating, electrical generation

• Variety of applications including solar vehicles and cooking

Page 17: Solar Thermal Systems

Overview:

• Converting solar radiation into heat for utility and industrial use

Page 18: Open Roof Top Solar Collectors

Design and Function:

• Integration into building architecture with advantages in heating water and air

Page 19: Flat Plate Collectors

Key Components:

• Description of structure and functions of flat panel collectors for heating purposes

Page 20: Performance Analysis for Collectors

Key Equation:

• Useful heat gain and solar flux regulation

Page 21: Evacuated Tube Collectors

Essential Features:

• Efficiency in colder climates with design details

Page 22: Solar Pond Collectors

Structure and Benefits:

• Layers function for heat retention and utilization

Page 23: Solar Air Heaters

Design and Functionality:

• Utilizing solar energy for efficient air heating applications

Page 24: Solar Concentrators

Overview of Types:

• Parabolic troughs and power tower designs detailed

Page 25: Types of Solar Thermal Collectors

Comparison:

• Different solar thermal collectors together according to efficiency and temperature ranges

Page 26: Resources for Further Study

• Websites and educational resources provided for comprehensive understanding

Page 27: Summary of Solar Photovoltaics

Key Aspects:

• Discussion on research opportunities in solar energy technology advancements