This document discusses different instruments used to measure solar radiation, including pyrheliometers, pyranometers, Eppley pyranometers, Yellott solarimeters, and sun shine recorders. Pyrheliometers measure direct/beam radiation using a sun tracking system, while pyranometers measure global radiation from the whole hemisphere using the temperature difference between hot and cold surfaces. Eppley pyranometers and Yellott solarimeters work on similar principles but use different sensor designs. Sun shine recorders measure the duration of bright sunshine using a spherical bowl that burns a trace on a card. Solar radiation data should specify if it is instantaneous or averaged measurements, the time period, radiation type (beam, diffuse

1. SOLAR RADIATION

2. SOLAR RADIATION MEASUREMENT

3. SOLAR RADIATION MEASUREMENT

4. SOLAR RADIATION

5. SOLAR RADIATION

6. SOLAR RADIATION

7. SOLAR RADIATION

8. PYRHELIOMETERS

9. PYRHELIOMETERS
• Measures only beam or direct radiation.
• Required sun tracking system.

10. ABBOT’S SILVER DISC PYRHELIOMETER
• BLACKEND SILVER DISK D
• MERCURY IN GLASS THERMOMETER T
• SUSPENDED DISK D FROM BLOCK B
• THERMOMETER STRIP BANT IN U SHAPE
• COLLIOMATOR TUBE AT 5.7 DEGREES
• THREE ROTATING SHUTTERS

11. PYRANOMETER

12. PYRANOMETER(Solarimeter)
(1) sensor, (2, 3) glass domes, (5) cable, standard length 5 m, (9) desiccant.
• Measures solar radiation received from the whole hemisphere.
• Global or sky radiation
• Difference between hot and cold surface is measured in terms
of e.m.f.
• Temperature difference between the hot and cold junctions is a
function of the radiation falling on the surface.

13. PYRANOMETER(Solarimeter)
• There are two methods to measure diffuse radiation.
• Method-1: In the combination of Phrheliometer
• Method-2: Using a special device preventing direct solar
radiation reaching the receiver of phranometer.
• A disk rotating with sun shades the receiver.
• Shading ring shaded the receiver from sun and thus only diffuse
radiation is measured.

14. Eppley Pyranometer
• Works as per previous principle.
• Concentric Silver rings coated black and white.
• Or in the later model, the wedges are arranged in circular
pattern with alternate black and while coatings.
• Calibrating of these kind of instruments are done keeping it in
horizontal position only. It may vary if kept inclined

15. Yellott solarimeter(Photo voltaic cell)
• Used with photovoltaic detectors.
• Light current is a linear function of the incident solar radiation
for photovoltaic cell.
• Disadvantage is that the spectral response is not linear, so
instrument calibration is a function of the spectral distribution
of the incident radiation.

16. Sun Shine Recorder
• Measures duration in hours of bright sun shine during the course of
the day.
• Spherical brass bowl burns a trace on the card.
• Length of trace being a direct measurement of the duration of bright
sunshine.
• 3 cards are used.
• The sphere acts as a lence
• Three overlapping pairs of
grooves are made for
various seasons.
• Doesn’t give the exact
sunshine due to less
intance burn in
morning and evening.

17. Sun Shine Recorder

18. Sun Shine Recorder

19. Sun Shine Recorder

20. Solar Radiation Data
Solar radiation data are available In several forms and should include
the following information.
1. Whether they are instantaneous measurement or values
integrated over some period of time.
2. The time or time period of the measurements.
3. Whether the measurements are of beam, diffuse or total radiation,
and the instrument used.
4. The receiving surface orientation
5. If averaged, the period over which they are averaged.