ENVIRONMENTAL LAW ppt on laws of environmental law
Principle of measurement of solar radiation
1. Principle of measurement of
solar radiation
(1)Principle of Thermocouple
(2)Photovoltaic principle
(3)Principle of solar concentration
2. PYRANOMETER
• Measure beam radiation + diffused radiation
• Measure diffused radiation when shading ring is used
PRINCIPLE
Black surface absorb
White surface reflect
unnecessary heat
Temp. Diff. of B and W detect
thermopile in mV
Calibration
3. PYRANOMETER
CONSTRUCTION
Thermopile with black & white coating
Absorb solar radiation of spectrum 300-50000 nm
wave length
Glass dome control spectral response of 300-2800
nm while 180 ͦfield view
Glass dome prevent leakage of heat radiation from
sensor
O/P in mV calibrated in Watt per square meter
4. PYREHELIOMETER
• Used to measure direct beam radiation
Principle:
Temperature difference between black and
white
↓
Converted into EMF
↓
proportional to energy incident on surface
5. Construction and Working:
Shape collimator tube
Thermopile junction at black side of
sensor plate
Cone angle at 50 degree
Solar sensor produce o/p in mV
PYREHELIOMETER
7. SUNSHINE RECORDER
• Use to measure duration of the day when there was bright sun
shine give beam radiation
CONSTRUCTION
Transparent glass sphere mounted on heavy base
Bowl provided below glass sphere
Grove is provided to insert paper
WORKING
Glass concentrate solar radiation
Paper receive solar radiation on it which is chemically
treated
Paper give burn mark
When the sun shine is present
8. PHOTOVOLTAIC SOLARIMETER
• Typical pyranometer measure solar flux intensity
• Working principle PV cell
• Solar energy Solar cell Variable resistive load
Current produced
• Moved in direction off sun
• Meter calibrated in
watt per meter square