Download Without the Greenhouse Effect the Earth would be 60 degrees colder.

Without the
Greenhouse Effect
the Earth would be
60 degrees colder.
n 1896 - Svante August Arrhenius published the first paper on global warming
The core science is simple
• Earth is in an energy balancing act with the sun
• Energy arrives and leaves as light
• The rate energy escapes
is a function of:
o Earth’s temperature
o Presence of GHG
• GHGs absorb infrared
light (heat) before it
escapes
Ice Core Data
Brief but stable
interglacial periods
Long and unstable
glaciations periods (ice ages)
Minimizing climate change is why we must
advance renewable energy must faster
International Panel on Climate Change (IPCC)
2001 Synthesis Report, Figure 6-2
The solution would stabilized
more than just the climate
Solar Radiation Components
• Beam radiation (direct)
• Diffuse radiation (atmospheric affects)
Beam radiation
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Solar Power - Irradiance
• 1,366 watts per square meter hits the Earth’s upper
atmosphere
Solar Irradiance
Atmospheric Effects
• Approximately 1,000 W/m2 reaches the Earth’s
surface
Air Mass
• Irradiance is reduced as the amount of atmosphere
the solar radiation passes through is increased
Solar Path
• Impact of Earth tilt as it moves around the sun.
Sun’s path across the sky
(northern hemisphere)
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Sun altitude
Sun azimuth
Tilt and Azimuth Angles
Tilt
Angle
Azimuth
Angle
Optimal Tilt
• Energy production at certain times of the year can
be optimized by adjusting the array tilt angle.
Minimum Slope = 5 degrees
• Low slope results in water pooling and dirt
25
Soft versus Hard Shadows
• Slender shadows cast from 30+ feet have
little effect in winter when half the sunlight
is diffuse and the shadow cast is soft
Soft Shadow
Hard Shadow
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Shading Impact on PV
shadows reduce module Voltage
Shading
1000
900
800
Watts output
700
600
500
400
300
200
100
12:01pm
0
9:07 AM
10:04 AM
11:02 AM
12:00 PM
Time of day
12:57 PM
1:55 PM
2:52 PM
12:09pm
Panels can shade eachother
Sun Chart – Cartesian
36
Sun chart: 14 N
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Site Survey – Before you visit
• Online Map Survey – Google and Bing Maps
• Get Billing Data
o 12 months of electrical consumption
• Interview Owner
o How much hot water is used
• Daily
• Weekly
o Sales information?
• Make a site checklist
o What do you want to find out?
Use Google earth and Bing maps
PlugandPlayEnergySystems.com