Instruments for solar radiation measurement Empirical equation for prediction of availability of solar radiation Radiation on tilted surface Types of solar collectors kushsshah.blogspot.com

1. Solar radiation
Present by
Shah kushal sanjaybhai(130670119596)
Shah milap jayendrabhai(130670119597)
Shah shaimin bharatbhai(130670119598)

3. Index
★ Instruments for solar radiation measurement
★ Empirical equation for prediction of availability of solar radiation
★ Radiation on tilted surface
★ Types of solar collectors

4. Instruments for solar radiation
measurement
A pyranometer is a type of actinometer used for measuring
solar irradiance on a planar surface and it is designed to
measure the solar radiation flux density (W/m2
) from the
hemisphere above within a wavelength range 0.3 μm to 3 μm.
The name pyranometer stems from the Greek words πῦρ (pyr),
meaning "fire", and ἄνω (ano), meaning "above, sky".

5. An older version of a pyranometer.
The picture shows its black sectors,
which absorb all of the radiation,
and white sectors, which measure
the shadow area. Irradiation is
proportional to the difference of
temperature of the two sectors.

6. Classification of pyranometer
Following the classifications and definitions noted in the ISO
9060, three types of pyranometers can be recognized and
grouped in two different technologies:
1) thermopile technology
2) silicon semiconductor technology.

7. Thermopile pyranometer
A thermopile pyranometer is a sensor based on thermopiles designed to measure the
broadband of the solar radiation flux density from a 180° field of view angle. A thermopile
pyranometer thus usually measures 300 to 2800 nm with a largely flat spectral sensitivity
(see the Spectral Response graph) The first generation of thermopile pyranometers had the
active part of the sensor equally divided in black and white sectors. Irradiation was
calculated from the differential measure between the temperature of the black sectors,
exposed to the sun, and the temperature of the white sectors, sectors not exposed to the sun
or better said in the shades.
In all thermopile technology, irradiation is proportional to the difference between the
temperature of the sun exposed area and the temperature of the shadow area.

8. Line drawing overview
of a thermopile
pyranometer, including:
(1) cable; (2) thumb
screw for the sun screen;
(3) inner dome; (4)
thermal sensor; (5)
outer dome; (6) sun
screen; (7) humidity
indicator; (8) desiccant
holder; (9) levelling feet;
(10) bubble level

9. Thermopile pyranometers
are frequently used in
meteorology, climatology,
climate change research,
building engineering
physics and in photovoltaic
systems. They are usually
installed horizontally in
meteorological stations;
when they are mounted
beside solar panels, they are
typically mounted with the
sensor surface on the plane
of the panel.

10. Photodiode based pyranometer Also known as a silicon pyranometer in
the ISO 9060,[4]
a photodiode-based pyranometer can detect the
portion of the solar spectrum between 400 nm and 900 nm, with the
most performant detecting between 350 nm and 1100 nm. The
photodiode converts the aforementioned solar spectrum frequencies
into current at high speed, thanks to the photoelectric effect. The
conversion is influenced by the temperature with a raise in current
produced by the raise in temperature (about 0,1% • °C)
Photodiode based pyranometer

11. pyrheliometer
A pyrheliometer is an instrument for measurement of direct beam
solar irradiance.[1]
Sunlight enters the instrument through a window
and is directed onto a thermopile which converts heat to an electrical
signal that can be recorded. The signal voltage is converted via a
formula to measure watts per square metre.[2]
It is used with a solar
tracking system to keep the instrument aimed at the sun. A
pyrheliometer is often used in the same setup with a pyranometer.

12. Pyrheliometer: (1)
protection cap,
(2) window with heater,
(3) sight,
(5) sensor,
(7) humidity indicator,
(10) cable for heater

13. Typical pyrheliometer
measurement
applications include
scientific
meteorological and
climate observations,
material testing
research, and
assessment of the
efficiency of solar
collectors and
photovoltaic devices.

14. Sun shine recorder
Sunshine recorder essentially consists of a glass sphere mounted in a
spherical bowl and a metallic groove which holds a record card. Sun's
rays are refracted and focused sharply on the record card beneath the
glass sphere, leaving burnt marks on the card.Sunshine recorder
essentially consists of a glass sphere mounted in a spherical bowl and a
metallic groove which holds a record card. Sun's rays are refracted and
focused sharply on the record card beneath the glass sphere, leaving
burnt marks on the card.

15. Sunshine recorder essentially consists
of a glass sphere mounted in a spherical
bowl and a metallic groove which holds a
record card. Sun's rays are refracted and
focused sharply on the record card
beneath the glass sphere, leaving burnt
marks on the card.

16. Older recorders required a human
observer to interpret the results;
recorded results might differ among
observers. Modern sunshine recorders
use electronics and computers for
precise data that do not depend on a
human interpreter. Newer recorders
can also measure the global and
diffuse radiation.

17. pyrgeometer
A pyrgeometer is a device that measures near-surface infra-red
radiation spectrum in the wavelength spectrum approximately from
4.5 µm to 100 µm.
It measures the resistance/voltage changes in a material that is
sensitive to the net energy transfer by radiation that occurs between
itself and its surroundings (which can be either in or out). By also
measuring its own temperature and making some assumptions about
the nature of its surroundings it can infer a temperature of the local
atmosphere with which it is exchanging radiation.

18. pyrradiometer
Pyrradiometer is a total hemispherical radiometer, used for exact
determination of net radiation in shortwave and longwave radiation
range with two separately working receivers and with a built-in
thermometer to determine reference temperature.

19. Empirical equation for prediction of
availability of solar radiation

20. Radiation
on tilted
surface

21. In addition to direct beam and diffuse light, a tilted surface will also be struck by rays reflected off the ground.
Accordingly, the radiation on a tilted surface has three components:
Beam Radiation
If RB denotes the ratio of the average daily beam radiation on a tilted surface to that on a horizontal surface, then the direct beam
part can be written as
RB is a pure geometric parameter, dependent on the horizontal tilt, surface azimuth, declination angle and latitude.
Diffuse Radiation
Assuming an isotropic distribution of the diffuse radiation over the hemisphere, the diffuse part is only dependent on the
horizontal tilt angle β and the diffuse radiation of the horizontal surface:
This takes into account that the tilted slope sees only a portion of the hemisphere.
Reflected Light
The energy of the reflected light is dependent on the ground’s ability to reflect, a property which is expressed by the albedo factor ρ.
The albedo ranges from 0.1 (asphalt paved road) to 0.9 (snow). Given the albedo, the reflected term can be calculated from:
Radiation on tilted surface

22. Types of solar collectors
1. Concentrating type solar collector
2. Non-concentrating type solar collector

24. “The solar system should be viewed as
our backyard, not as some sequence of
destinations that we do one at a time. c
”
- neil degrasse tyson

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