Day 2: Energy Generation Energy Harvesting Day 2: Energy Generation April 16, 2013 Paul Nickelsberg Orchid Technologies Engineering and Consulting, Inc. www.orchid-tech.com

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

Energy Generation Photoelectric Energy Generation Magnetic - Inductive Energy Generation Radiated Energy Generation

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 10 - 20 350 Grocery Store 15 – 25 400 Department Store 20 – 35 500 Overcast Sky 50 - 200 1000 Bright Sunlight 500 - 1000 100000 Conversion between W/m² and Lux is Approximate and dependant upon spectral content of light 4

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

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

Photoelectric Energy Generation Courtesy Linear Technologies Corporation 7

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

Photoelectric Energy Generation Courtesy Linear Technologies Corporation 9

Photoelectric Energy Generation Courtesy Linear Technologies Corporation 10

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

Photoelectric Energy Generation G24 Innovations • Indy2050 length = 50mm 228uW @ 1000 lux 45uW @ 200 lux • Indy2100 length = 100mm 477uW @ 1000 lux 88uW @ 200 lux • Indy2200 length = 200mm 948uW @ 1000 lux 171uW @ 200 lux 12

Photoelectric Energy Generation Courtesy Power Film Solar 13

Photoelectric Energy Generation Courtesy Ixsys 14

Magnetic - Inductive Generation Courtesy Perpetuum Data Sheet 15

Magnetic - Inductive Generation Courtesy Perpetuum Data Sheet 16

Radiated - Inductive Generation Transmitter Receiver Energy Source Energy Sink 17

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

Radiated - Inductive Generation 100 KHz 19

Radiated - Inductive Generation 100 KHz 20

Radiated - Inductive Generation 14 MHz Courtesy Cymbet Data Sheet 21

Radiated - Inductive Generation 900 MHz Courtesy Powercast Data Sheet 22

Radiated - Inductive Generation 900 MHz Courtesy Powercast Data Sheet 23

Energy Generation Come back tomorrow 24