SolPowerPeople #SolarMOOC Demonstration on PV System Design using PVSYT by Dr. Jeffery Lee Johnson of TodoSolar

1. Demonstration of PV system design
Using PVSYST
Dr. Jeffery Lee Johnson
CTO Todo-Solar
Coahuila, Mexico
Email: jeff.johnson@todosolar.mx Tele: 871 722 9522 Skype: todosolarmexico

2. Agenda
• Resources
• A review of the basic principles of Photovoltaic Engineering
• What is PV System design?
• Initial Project Assessment: Matching Kwh of consumption (energy
needed) to solar Kwh produced using an actual Case Study
• Case Study in Design : A real time design demonstration using PVSYS
• Comparison of predicted performance to actual performance
• Special features of PVSYST, compatibility with other resources
• TodoSolar and TodoSolarKids

3. Resources
Doc Solstice’s Seasoned Sentiments
The question of the day that is on everybody’s minds
Does Solar Energy have a future ?

4. Resources
Doc Solstice’s Seasoned Sentiments
The question of the day that is on everybody’s minds
Does Solar Energy have a future ?
Solar Energy is here and is here to stay

5. BASIC PRINCIPLES OF
PHOTOVOLTAIC ENGINEERING

6. Key Concepts and Equations
• The mathematics of PV engineering relies mostly on a single
equation - The Schockley diode equation
• Watts peak : The Power output of a panel under specific conditions
– 1000 W / m2 solar radiation normal (perpendicular to surface) at 25 C and 1 atm.
– A normalized quantity that is helpful but not useful and is confusing
• Specific yield – The PV designer’s best friend
– Specific yield is the Kwh produced per KWp installed per day (Kwh/KW/day)
– It is normalized quantity independent of total size of system
• Specific yield depends on
– Geographical location and climate (solar resource)
– Installation and orientation
– Design by matching components for optimum performance

7. The Shockley Diode Equation
(The physics of the P-N Junction)
eV V
I I0 exp 1 I0 exp 1
kT Vthermal
e
where Vthermal 26mV at 300K
kT

8. A First Look at the Diode Equation
eV V BLUE CURVE
I I0 exp 1 I0 exp 1
kT Vthermal
e
where Vthermal 26mV at 300K
kT

9. Photo-active materials
(semiconductors)
Photon
Effect on diode equation

10. The photovoltaic Equation and curve
V RED CURVE
I I 0 exp 1 I PH
Vth
I I I0

11. The Photodiode is at the heart of every opto-
electronic device including solar cells
Power = I x V Lasers
Electrical diode
Photodiodes Solar Cells

12. The Solar Cell Isc and Voc

13. Variation with Temperature and Irradiation

14. Variation of Isc and Voc with Radiation
ISC varies linearly in proportion with illumination
q I ph Voc varies logarithmically
VOC ln 1
kT I0 with illumination

15. ISC and VOC variation with
Temperature
ISC varies little
with changes in
temperature
q I ph
VOC ln 1
kT I0
q I ph Voc Is inversely proportional with
VOC ln 1
kT I0 temperature

16. Solar Cell Power
P I V
V
P V IL I0 exp 1
Vthemal
dP dP
Vmax 0 I max 0
dV dI

17. Maximum Power point tracking
All modern inverters have MPPT capability that optimizes the power point for a
string or array of solar panels

18. WHAT IS PV SYSTEM DESIGN?

19. Panel and series characteristics
String is a series of panels with
predetermined current and
voltage output
V = V1 + V2 + …Vn = ∑ Vi
I = I1 = I2 = …In

20. Inverter characteristics
Inverters have input requirements
•Number of DC inputs
•Minimum/Maximum current
•Minimum/Maximum Voltage
•MPPT range of Voltage

21. Matching the panels with inverter is
called “String Sizing”

22. Matching the panels with inverter is
called “String Sizing”
Inverters have Output characteristics
•Peak Power
•Specific Yield
•Grid connection compatibility
•Annual Production of energy
Kwh

23. Matching all components to generate the desired power
and energy output for a client is the called “PV system
Design”

24. INITIAL PROJECT ANALYSIS
A CASE STUDY IN DETERMINING KWH NEEDED

25. Collect data from Client
 Utility bill provides
consumption and prices for a
year
 We know the precise
geographical location
 A site visit provides:
• the area available
• orientation possibilities
• shading issues
• Grid connection
• Electrical interface
We can now begin the design

26. Using consumption needs to estimate sizing
Needs 26,823 Kwh per year. Using a Specific yield of 4.5. this client
needs a minimum system of 16 KW

27. A CASE STUDY IN PV SYSTEM DESIGN
USING PVSYST

28. PVSYST Simulation Software
http://www.pvsyst.com/

29. DEMO

30. COMPARING PREDICTED WITH
ACTUAL PERFORMANCE
USING SYSTEM MONITORING

31. http://www.sma-america.com/en_US.html
http://www.sunnyportal.com/Templates/Start.aspx
http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?plant=e40d
994b-9238-4c84-818b-82c731316308&splang=en-US

33. SPECIAL FEATURES OF
PVSYST

34. (Solar Energy made available to Everyone)
Twitter: @TodoSolar Twitter: @TodoSolarKids
http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?p
lant=e40d994b-9238-4c84-818b-82c731316308&splang=en-US