Transcript Document
Energy Scavenging A Look at Nano-fibers and Other Piezoelectric Devices for Body Area Networks Presented by Stuart Wooters Outline • Characteristics of Movement Scavenged Energy • Nano-Fibers • PVDF • Potential Implementations • Design considerations Characteristics: • What are some of the requirements of movement generated energy? – Frequency Range – Types of Movement – Energy Potentials Microfibre–nanowire hybrid structure for energy scavenging Yong Qin1, Xudong Wang1 & Zhong Lin Wang1 Basic Concept • Use vibrations and friction between two fibers to create an electric current. • Textile fibers are dense and have the potential of accumulating a lot of energy. Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. Structure • Fibers are coated in a Zinc Oxide growth. Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. Conceptual Analogue Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. IV Curve of Coated Strand Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. (Supplement Figure 1) IV Curve of Bent Strands Diode characteristics help insure same direction current for all nano-fibers Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. (Supplement Figure 2) Short Circuit and Open Circuit Measurements at 80rmp Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. Range of Frequencies Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. (Supplement Figure 6) Six Fibers Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. (Figure 4) Viability Case 1 (Cylindrical Fibers) P=4nA x 3mV / .2s = 60pW Effective Power: 19 mW per 1m2 Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. (Supplement) Viability Case 2 (Square Fibers) P=4nA x 3mV / .2s = 60pW Effective Power: 76 mW per 1m2 Yong Qin , Xudong Wang & Zhong Lin Wang "Microfibre-nanowire hybrid structure for energy scavenging", Nature, Volume 451, 14 February 2008 Page(s): 809 - 814. (Supplement) Energy Generation using Piezo Film R H Brown, Atochem Sensors Ltd, 1991 Basic Equations • Charge Density: D = Q/A = d3nXn • Open Circuit Voltage V0 = g3nXnt R H Brown “Energy Generation using Piezo Film” published by Measurment Specialties original publish year 1991 Energy Expectations • Maximum Charge Density: – 7mC/m2 • Maximum Energy Expected: – 200 kJ/m3 R H Brown “Energy Generation using Piezo Film” published by Measurment Specialties original publish year 1991 PVDF (Polyvinylidene Fluoride) • Generates energy through stress/strain • Kinetic Energy to Electrical Energy – Dropping Ball test – Stepping test R H Brown “Energy Generation using Piezo Film” published by Measurment Specialties original publish year 1991 Basic Measurements R H Brown “Energy Generation using Piezo Film” published by Measurment Specialties original publish year 1991 Potential Implementations • How can we incorporate these devices into our networks? • Can they be more than good sensors? Design Considerations • What do you do when your not scavenging energy? • How do you retain your energy? • How would you control different energy modalities?