UNIT-II SOLAR ENERGY

PART-A
1. What is meant by solar radiation?
Solar radiation, often called the solar resource or just sunlight, is a general term for the
electromagnetic radiation emitted by the sun. Solar radiation can be captured and turned into useful
forms of energy, such as heat and electricity, using a variety of technologies.
2. What are the three types of solar radiation?
The three relevant bands, or ranges, along the solar radiation spectrum are ultraviolet, visible
(PAR), and infrared. Of the light that reaches Earth's surface, infrared radiation makes up 49.4% of
while visible light provides 42.3% 9. Ultraviolet radiation makes up just over 8% of the total solar
radiation.
3. How does solar radiation cause climate change?
A warming of the planet due to an increase in solar irradiance probably results in the release
of methane and carbon dioxide from stores in the oceans and icecaps, and these greenhouse gases can
then produce additional warming.
4. What are the 4 solar radiations?
Solar radiation is sunlight and energy that comes from the sun and travels to Earth in the form
of light waves. Light waves come in different forms, vibrate, and have different lengths and energy
levels. They are electromagnetic, which means that they contain vibrating electric currents and
magnetism.
5. What is the unit of solar radiation?
Radiation data for solar electric (photovoltaic) systems are often represented as kilowatt-hours
per square meter (kWh/m2). Direct estimates of solar energy may also be expressed as watts per
square meter (W/m2).
6. What are four types of radiation from the Sun?
All of the energy from the Sun that reaches the Earth arrives as solar radiation, part of a large
collection of energy called the electromagnetic radiation spectrum. Solar radiation includes visible
light, ultraviolet light, infrared, radio waves, X-rays, and gamma rays
7. How to measure solar radiation?
Solar radiation measurement | HuksefluxPyrheliometers are commonly used to measure the
direct sunlight, thus need to track the position of the sun during the day. Pyrheliometers have
standardized 38 mm diameter tubes so they can easily be mounted on a solar tracker.
8. What are the main parts of solar radiation?
The three main components of solar radiation So the three main components of solar radiation
are the direct, the diffused and the reflected solar radiation. Direct radiation is intercepted unimpeded,
in a direct line from the sun. Diffuse radiation is scattered by at- mospheric constituents, such as
clouds and dust.
9. What is the size of solar radiation?
Approximately 99% of solar, or shortwave, radiation at the earth's surface is contained in the
region from 0.3 to 3.0 µm while most of terrestrial, or longwave, radiation is contained in the region
from 3.5 to 50 µm. Outside the earth's atmosphere, solar radiation has an intensity of approximately
1370 watts/meter2.
10. Ways of measurement of Solar Radiation
The measurements are taken using either a pyranometer for measurement of global radiation
and/or a pyrheliometer for measurement of direct radiation. A less accurate –yet less expensive-
alternative method for measurement of solar radiation, is using a sunshine recorder.22 Apr 2019.
11. What are the measurements of solar radiation?
Measurements of solar energy are typically expressed as total radiation on a horizontal
surface or as total radiation on a surface tracking the sun. Radiation data for solar electric
(photovoltaic) systems are often represented as kilowatt-hours per square meter (kWh/m2).
12. How we measure sunshine and radiation - Met Office
Sunshine is measured using either Campbell-Stokes sunshine recorders or modern sunshine
sensors. A pyranometer is used for measuring global radiation.
13. What is the instrument for measuring solar radiation and sun shine?
A pyranometer is used to measure global solar radiation falling on a horizontal surface.
14. What is the SI unit for solar radiation?
Solar irradiance watts per square metre
The SI unit of irradiance is watts per square metre (W/m2 = Wm−2). The unit of insolation often
used in the solar power industry is kilowatt hours per square metre (kWh/m2).

15. What is the sunshine unit of radiation?

The strontium unit was formerly known briefly as the sunshine unit, the name was derived
from a recognizable source of background radiation (the Sun), and been used as a convenient
measure. Ten sunshine units are comparable to natural background radiation.
16. What tool is used to measure solar radiation?
Instruments to measure solar radiation
MEASURAND INSTRUMENT
global horizontal irradiance pyranometer
solar radiation on a tilted plane pyranometer
 irradiance in the 'plane of array' pyranometer
direct solar radiation pyrheliometer on a solar tracker
17. Write the function of Solar spectrum.
Solar spectrum refers to the distribution of solar irradiation across different wavelengths,
including UV light, visible light (sunlight), and near-infrared light. It plays a crucial role in
efficiently harnessing solar energy through photocatalysis

18. What is AM 1.5 solar spectrum?

The AM 1.5 Standard Spectrum refers to exactly two standard terrestrial solar spectral
irradiance spectra. The two spectra define a standard direct normal spectral irradiance and a standard
total (global, hemispherical, within steradian field of view of the tilted plane at from horizontal)
spectral irradiance.
19. What is the difference between AM1 5G and D?
The “D” in AM1. 5D stands for directed, and corresponds to sunlight that directly shines on a
point on Earth (i.e. with no reflections or scattering). AM1. 5G corresponds to a global spectrum that
includes diffuse and scattered light.
20. What is the standard for AM 1.5 g?
To facilitate the comparison of solar conversion efficiency measurements taken at different
times and locations, AM 1.5G is defined as the reference spectrum for standard testing of solar
energy conversion systems, with a specified standard irradiance of 1000 W/m2.
21. Enumerate Solar thermal collectors.
Solar thermal collectors are devices that absorb solar radiation and convert it into heat. Then,
the generated heat is transferred by a HTF to provide the heat demand of a specific application.
22. What is the most common use of solar thermal collectors?
Solar thermal collectors - U.S. Energy Information
People use solar thermal energy for many purposes, including heating water, air, and the
interior of buildings and generating electricity. There are two general types of solar heating systems:
passive systems and active systems.
23. What is solar thermal collector vs PV?
As the name suggests, solar thermal technology is used to collect sunlight and transform it
into heat that is stored and later on transformed into electricity. Solar panels, on the other hand,
utilise PV technology to capture sun rays and directly convert the sunlight into electricity.

24. What are the applications of solar thermal collectors?

Solar thermal systems are mostly used in residential and industrial applications such as
domestic water heating, heating of swimming pools, space heating, water processes for industrial
heating and agricultural drying.
25. What is the heat transfer in a solar collector?
Solar collector represents a heat exchanger, in which receive solar radiation, transform it to
heat and transfer this heat to the working fluid in the collector's channel The radiation and convection
heat transfer processes inside the collectors depend on the temperatures of the collector components.
26. Write the purpose of using flat plate and concentrating collectors.
The main differences are in efficiency and use. Flat plate collectors are simple and low cost,
good for both direct and scattered sunlight. Concentrating collectors get very hot and are more
efficient, but they need to track the sun and are more complex and expensive.
27. What is the concentration ratio of a flat plate collector?
The concentration ratio of a flat plate collector is a measure of how much more concentrated
the solar radiation is on the absorber plate compared to the incident solar radiation. It is typically a
value between 1 and 10, depending on the design of the collector and the conditions in which it is
used.
28. What is the principle and working of flat plate collector?
Flat Plate Solar Collector: Working, Types, Components & Benefits
A Flat plate collector is a solar panel device that uses solar energy to generate thermal energy.
It converts solar power into thermal energy, i.e., cheaper energy utilising water as an operating fluid.
A Flat plate solar collector takes in solar radiation and transmits heat to the functioning medium.
29.Which collector has the maximum concentration ratio?
Therefore, the solar collector that has the highest concentration ratio is a paraboloid dish
collector. A compound parabolic collector with a plane receiver has a concentration ratio of 1.7.
Fresnel lens collector has a concentration ratio of 1500. The cylindrical parabolic collector has a
concentration ratio of 20.
30. What is the value of the concentration ratio of a flat plate collector?
The concentration ratio of a flat plate collector is a measure of how much more concentrated
the solar radiation is on the absorber plate compared to the incident solar radiation. It is typically a
value between 1 and 10, depending on the design of the collector and the conditions in which it is
used.
31. What is the concentration ratio of solar collectors equation?
Solar energy collectors (Concentration ratio is defined as the aperture area divided by the
receiver/absorber area of the collector.
32. What are the applications of solar thermal?
Low temperature solar thermal systems collect solar radiation to heat air and water for
industrial applications including: Process industry, boiler feed, laundry and canteens. Agricultural
sector, hatcheries and dairies. Process industry, Boiler feed, Laundry and canteens.
33. What are the 10 major applications of solar energy?
Discovering the Many Applications of Solar Energy: Harnessing ...
10 Major Applications of Solar Energy – Explained!
 Solar Water Heating.
 Solar Heating of Buildings.
 Solar-Distillation.
 Solar-Pumping.
 Solar Drying of Agricultural.
 Solar Furnaces.
 Solar Electric Power Generation.
 Solar Thermal Production.
34. Where is solar thermal used?
Low-temperature collectors are generally unglazed and used to heat swimming pools or to
heat ventilation air. Medium-temperature collectors are also usually flat plates but are used for
heating water or air for residential and commercial use. Roof-mounted close-coupled thermosiphon
solar water heater.
35. What are three advantages of solar thermal?
The benefits of solar heating:
Endless amounts of energy, free of charge. No CO2 emissions during operation. Cost savings:
up to 60% less energy to heat water, up to 35% less energy for space heating. Reduced consumption
of fossil fuels.
36. Write the advantages of solar thermal energy.
 From sources across the web
 Cheaper electricity bills
 Reduce your carbon footprint
 Low-maintenance
 Renewable energy
 Solar energy is renewable
 Fossil fuel dependency reduction
 Solar thermal is environmentally friendly
 Solar panels are getting cheaper
 Diverse applications.
37. What is the main benefit of using solar thermal energy?
The benefits of solar heating:
Endless amounts of energy, free of charge. No CO2 emissions during operation. Cost savings:
up to 60% less energy to heat water, up to 35% less energy for space heating. Reduced consumption
of fossil fuels.
38.What is solar energy thermal storage?
Thermal energy storage provides a workable solution to this challenge. In a concentrating
solar power (CSP) system, the sun's rays are reflected onto a receiver, which creates heat that is used
to generate electricity that can be used immediately or stored for later use.
39. What materials are used in solar thermal storage?
A number of materials will work as storage media in home, farm or small business solar
heating systems; but only three are generally recommended at this time--rock, water (or water-
antifreeze mixtures) and a phase-change chemical substance called Glauber's salt.
40. Write short notes on Photovoltaic cells conversion
A photovoltaic (PV) cell, commonly called a solar cell, is a nonmechanical device that
converts sunlight directly into electricity. Some PV cells can convert artificial light into electricity.
Sunlight is composed of photons, or particles of solar energy.
41. What is the principle of solar photo voltaic energy conversion?
A photovoltaic (PV) panel, also known as a module, is a unit consisting of special cells that
generate an electric current in sunlight that are linked together. When the sun shines over the cells, an
electric field is created. The stronger the sun, the more electric energy is produced.
42. What are the basics of solar energy conversion?
Solar technologies convert sunlight into electrical energy either through photovoltaic (PV)
panels or through mirrors that concentrate solar radiation. This energy can be used to generate
electricity or be stored in batteries or thermal storage.
43. What is meant by solar cell?
A photovoltaic (PV) cell, commonly called a solar cell, is a non-mechanical device that
converts sunlight directly into electricity. Some PV cells can convert artificial light into electricity.
Sunlight is composed of photons, or particles of solar energy.
44.What are the types of solar cells?
The following are the different types of solar cells.
Amorphous Silicon solar cell (a-Si)
Biohybrid solar cell.
Cadmium telluride solar cell (CdTe)
Concentrated PV cell (CVP and HCVP)
Copper indium gallium selenide solar cells (CI(G)S)
Crystalline silicon solar cell (c-Si)
Float-zone silicon.
45. What is the principle of solar cells?
When the semiconductor is exposed to light, it absorbs the light's energy and transfers it to
negatively charged particles in the material called electrons. This extra energy allows the electrons to
flow through the material as an electrical current.
46. What are the 4 characteristics of solar cells?
The basic characteristics of a solar cell are the short-circuit current (ISC), the open-circuit
voltage (VOC), the fill factor (FF) and the solar energy conversion efficiency (η).
47. What is the fundamental of solar cell?
A solar cell is a sandwich of n-type silicon and p-type silicon . It generates electricity by
using sunlight to make electrons hop across the junction between the different flavors of silicon:
When sunlight shines on the cell, photons (light particles) bombard the upper surface.
48. What is the solar PV system?
A photovoltaic (PV) panel, commonly called a solar panel, contains PV cells that absorb the
sun's light and convert solar energy into electricity. These cells, made of a semiconductor that
transmits energy (such as silicon), are strung together to create a module. A typical rooftop solar
panel has 30 modules.
47. What are the properties of a solar cell?
The properties of solar cells are:
The solar cells are P-N junction diodes connected in reverse bias. -When light is focused on
the junction of the diode there is a generation of current in it. -This current is reverse current. -The
existence of this reverse current depends on the certain frequency of the light.
50. What is the difference between solar system and PV system?
Photovoltaic panels are installed for the conversion of thermal energy into electricity, while
solar panels convert solar radiation into heat. This is why these solutions do not compete with each
other. Instead, they may complement each other.
51. What are the different types of PV systems?
Different Types of Solar PV Systems | On Grid, Hybrid & Off
There are three main types of solar PV systems: grid-tied, hybrid and off-grid.

52. What are the applications of solar PV technology?

Solar PV Modules: Features, Applications, and Working ...
Applications of Solar PV Modules. Residential and Commercial Use: Solar PV modules are
widely used for residential and commercial applications. They are used to power homes, businesses,
and industrial facilities. They are a cost-effective solution for reducing energy costs and providing
clean energy.
53. Summarize the main applications of solar PV systems.
Systems mainly for electricity conservation:
Solar street lights
Solar traffic signals
Solar blinkers
Solar power packs/inverters
Solar illuminating hoardings/ Bill boards
Other systems of community use as felt necessary by Implementing Agencies
54. Systems for abatement of diesel & other fuel oil
Roof top SPV systems with or without grid interaction
The systems other than roof top will be installed on demonstration basis in autonomous mode
with grid acting as a stand by arrangement for charging the batteries through rectifier/inverter during
cloudy/rainy days, if necessary. Retrofitting of existing conventional system with solar may be done
to avoid high cost of installations wherever possible. Partial support in form of capital subsidy will be
available for installation of these systems from the Ministry.
55. What are the industrial applications of solar energy?
Solar energy can be used to generate heat for a wide variety of industrial applications,
including water desalination, enhanced oil recovery, food processing, chemical production, and
mineral processing, among many others.