1. Day 2: Energy Generation
Energy Harvesting
Day 2: Energy Generation
April 16, 2013 Paul Nickelsberg Orchid Technologies Engineering and Consulting, Inc.

2. Energy Harvesting Review
Energy harvesting is the process of capturing trace amounts of naturally occurring energy from various sources.
Accumulating the Energy
Storing the Energy
Applying the Energy for Useful Purpose

3. Energy Generation Photoelectric Energy Generation
Magnetic - Inductive Energy Generation
Radiated Energy Generation

4. Photoelectric Energy Generation
Illumination
Watt/m² - Approx
Lux - Approx
Dark City Limit 1 4
Warehouse
2 – 6 50
Office Space
9 - 15
100
Meeting Rooms
350
Grocery Store
15 – 25
400
Department Store
20 – 35
500
Overcast Sky
1000
Bright Sunlight
100000
Conversion between W/m² and Lux is Approximate and
dependant upon spectral content of light 4

5. Photoelectric Energy Generation
Light levels vary over approx 3 orders of magnitude
Courtesy Linear Technologies Corporation 5

6. Photoelectric Energy Generation
Cell Type
Spectral Sensitivity
Relative
Efficiency
cost
Monocrystalline
300 – 1100 nm
15% – 22%
High Cost
Polycrystalline
500 – 1100 nm
12% - 14%
Medium Cost
Amorphous
300 – 600 nm
4% - 6%
Low Cost
Non-Silicon Film
5% - 10% 6

7. Photoelectric Energy Generation
Courtesy Linear Technologies Corporation 7

8. Photoelectric Energy Generation
In an open circuit (no load current), power is 0.
In a short circuit (no load voltage), power is 0.
In between these extremes there is a “sweet spot” where maximum power is extracted from the cell.
How do we keep the solar cell in the maximum power point?
Courtesy Linear Technologies Corporation 8

9. Photoelectric Energy Generation
Courtesy Linear Technologies Corporation 9

10. Photoelectric Energy Generation
Courtesy Linear Technologies Corporation 10

11. Photoelectric Energy Generation
LTC3105 Max Output Power vs Lux with various Thin Film solar cells
Vout=3.3V, 4 cell in series, approx 25/50/100 cm²
100 cm²
50 cm²
25 cm²
161uW
Only ~200 Lux required to meet example application limits with some cells
Courtesy Linear Technologies Corporation 11

12. Photoelectric Energy Generation
G24 Innovations • Indy2050
length = 50mm
lux
200 lux
• Indy2100
length = 100mm
lux
200 lux
• Indy2200
length = 200mm
lux 200 lux 12

13. Photoelectric Energy Generation
Courtesy Power Film Solar 13

14. Photoelectric Energy Generation
Courtesy Ixsys 14

15. Magnetic - Inductive Generation
Courtesy Perpetuum Data Sheet 15

16. Magnetic - Inductive Generation
Courtesy Perpetuum Data Sheet 16

17. Radiated - Inductive Generation
Transmitter
Receiver
Energy Source
Energy Sink 17

18. Radiated - Inductive Generation
Frequencies of Interest
100 KHz
14 MHz – RFID Frequency
900 MHz – ISM Band, Wi-Fi Energy
2.4 GHz – ISM Band, Wi-Fi Energy 18

19. Radiated - Inductive Generation 100 KHz19

20. Radiated - Inductive Generation 100 KHz20

21. Radiated - Inductive Generation 14 MHz
Courtesy Cymbet Data Sheet 21

22. Radiated - Inductive Generation 900 MHz
Courtesy Powercast Data Sheet 22

23. Radiated - Inductive Generation 900 MHz
Courtesy Powercast Data Sheet 23

24. Energy Generation
Come back tomorrow 24