Exploring Current Trends of Energy Harvesting

Introduction

With the widespread improvements in the field of MEMS (Micro-electromechanical systems) with tiny mechanical devices such as sensors, valves, gears, mirrors, and actuators embedded in semiconductor chips and as sensors are required in these devices and these devices need to have a long lifespan. In MEMS using Batteries are not always beneficial since they need human involvement to exchange them. Hence, obtaining the electrical power desired to operate these devices is the main worry. To overcome this alternate type of energy source to conventional batteries must be well-thought-out. Energy utilization is swiftly growing day by day and hence novel and proficient energy resources are need to be discovered. Researchers are discovering new ways of utilizing abundant renewable energy from different sources and it is an ongoing research topic.

The various kinds of typical ambient energies are thermal energy, sunlight, RF energy and mechanical energy. The energy harvesting sources can be used to surge the lifetime and capability and to run these sensor devices by moreover switching or increasing the battery usage (Beeby et al., 2006; Kansal et al., 2003; Kansal et al., 2004; Kansal et al., 2005; Meninger, 1999; Rahimi et al., 2003). The energy that can be obtained from different energy sources by selecting the thermal, light, or mechanical energies accessible in the surrounding locations. This process aids in providing unlimited energy for the lifetime of the electronic device. Hence, the process of extracting energy from the ambient environment and altering it into expendable electrical energy is identified as energy harvesting or power scavenging. The energy obtained from numerous sources and used in growing technological demand. Energy harvesting is capturing energy from environment and storing the energy for gathering the imminent needs. Most popular several energy harvesting traditional mechanisms are such as energy produces form wind farms, energy generated from solar farms, energy generated from geothermal farms, tidal energy farms and so on. Advancement in technology has improved the way by which these sources can be used to power electronic systems. All stated popular energy harvesting mechanisms have been well established which leads to the development of self-powered systems which require very less maintenance and can be deployed in unreachable locations anywhere easily. The main target of energy harvesting is to power this self-powered system.

The classification of energy harvesting is made on the base of the method of energy scavenging the power. Renewable sources of energy comprise are characterized on the basis of the numerous sources which are Solar energy, tidal energy wind energy, and thermal energy for energy harvesting which contain from photovoltaic cells, wind turbines, thermoelectric generators and mechanical vibration devices such as piezoelectric devices, electromagnetic devices. However different methods impose varied restrictions on the working environment of electronic devices based on the type of energy they belong to and the source of energy they gain power from unlike all these sources of energy, mechanical energy can be found in examples when others become inadequate. The different source of mechanical energy can be gained vibrations, heat, motion, noise, flow induced vibrations etc., Mechanical energy can be used to power electronic systems by harvesting energy from it. Piezoelectric materials, pyro electric materials, electrostatic materials are used to convert the mechanical energy into useful energy form. For example piezoelectric harvesting devices scavenge into operational electrical energy from mechanical energy. Table 1 shows several harvesting methods by their power generation capability (Atwood et al., 2001).