Energy Harvesting Technologies

OBJECTIVE: To provide innovative technologies and system components which increase the lifetime and utility of various systems within DTRA"s Tag, Track, and Locate (TTL) portfolio to combat weapons of mass destruction (WMD). The specific innovations sought under this topic are improved technologies that advance the state of the art for energy scavenging or capture from the ambient environment and high energy density storage. DESCRIPTION: DTRA"s TTL systems are built from an extensible architecture and are designed to enhance the observable signatures of personnel and objects associated with the development, production, storage, or use of Weapons of Mass Destruction. TTL subsystems may include sensors to detect chemical, biological, or nuclear weapons materials or their precursors, and may include radio transmitters to broadcast data such as sensor detections and tag location. A single transmission of tag location information currently requires approximately 4 milli-Joules of energy, and operation of a typical chemical sensor for four minutes can consume an additional 3 milli-Joules. These rates of energy usage consume the energy stored within two commercial lithium batteries (CR123) in approximately two days while it is desirable for TTL systems to endure for weeks or months. Increasing the lifetime of the TTL systems can be accomplished through a combination of active power management, and capturing energy present within the TTL system"s deployment environment. The continuous collection of several micro-Watts of power would yield enough energy to operate a TTL tag transmitter and sensor for a few minutes each hour. Several technologies exist to extract energy from the environment. Reference 1 discusses photovoltaic technologies developed through the Department of Energy"s Solar Energy Technologies Program, and reference 2 is a review article that discusses technologies suitable for recovering energy from mechanical vibrations. Energy harvesting technologies will develop power sub-systems that will enhance the persistence of TTL systems by both capturing and storing ambient energy. Energy harvesting technologies of interest include: Energy capture: 1) High efficiency photovoltaic cells 2) Micro electromechanical machines (MEMS) electromagnetic generators to harvest mechanical vibration energy 3) Piezoelectric materials to harvest mechanical vibration energy 4) Rectifier-antenna (rectenna) systems to harvest electromagnetic energy Energy Storage: 1) Small, high-energy density batteries 2) Small, high-energy density capacitors 3) Novel miniature fuel cells PHASE I: Provide documentation that identifies one or more novel energy harvesting technologies to support TTL applications for combating WMD. Such documentation should include the pros / cons of those technologies, feasibility and cost performance / benefits analyses, as well as prototype designs that demonstrate meaningful improvements in the state-of-the-art. Candidate technologies should address the following characteristics (not in order of priority): High collection efficiency (capture devices) Output power available (capture devices) Energy generation density (milliwatts per unit volume: capture devices) Energy storage density (Joule per unit volume: storage devices) Device size (energy collection and storage systems should be smaller than a commercial"C"cell battery) Environmental constraints such as temperature, humidity, or vibration limitations Ease of integration with TTL sensor and transmitter payloads (which currently are powered by Li-polymer batteries) Technology readiness Manufacturing cost PHASE II: Develop complete engineering designs and demonstrate a prototype energy harvesting technology integrated with a representative TTL system. PHASE III DUAL USE APPLICATIONS: Produce low-rate production quantities for military and commercial markets. Potential commercial applications include powering distributed sensor networks for environmental monitoring such as: agricultural applications that monitor soil humidity to provide water on demand; or security applications that monitor personnel intrusions through ground vibrations. REFERENCES: 1. U.S. Department of Energy, Solar Energy Technologies Program, Multi-Year Program Plan 2008-2012, April 15, 2008. 2. Beeby, S. P., et al; Energy harvesting vibration sources for microsystems applications; Measurement Science and Technology, Vol. 17 (2006), R175-R195. 3. Chalasani, Sravanthi and Conrad, James M.; A Survey of Energy Harvesting Sources for Embedded Systems; IEEE Southeastcon 2008; 3-6 April 2008; pp. 442-447. 4. Garbuio, L., et al; Mechanical Energy Harvester with Ultralow Threshold Rectification Based on SSHI Nonlinear Technique; IEEE Transactions on Industrial Electronics; Volume 56, Issue 4, April 2009; pp. 1048-1056.