April 24, 2024
Energy Harvesting Systems

Energy Harvesting Systems: An Introduction to a Sustainable Future

Energy harvesting, also known as power harvesting or energy scavenging, is the process where energy is derived from external sources (such as solar power, thermal energy, wind energy, salinity gradients, and kinetic energy), captured and stored for small, wireless autonomous devices, usually electronics or electric systems.

Types of Energy Harvesting Systems

Vibration Energy Harvesting
Vibration energy harvesting utilizes kinetic energy from vibrations in the local environment to produce electricity. Piezoelectric and electromagnetic transducers are commonly used to convert the vibrational kinetic energy into electrical energy. Applications include energy harvesting from machines, vehicles, buildings and biomechanical motions. Many small devices like wireless sensors can be powered with ambient vibration energy harvesting systems.

Thermal Energy Harvesting
Thermal energy harvesting relies on temperature differences to generate electricity. Seebeck effect utilizes the temperature difference between two dissimilar conductors to produce DC voltage. Peltier effect converts heat flux into electric current. Thermocouples producing tiny amounts of power from ambient heat sources are common thermal energy harvesting systems. Thermal gradients from industrial processes, electronics, human/animal bodies can be tapped as sources of thermal energy.

Solar Energy Harvesting
Solar Energy Harvesting Systems utilizes photovoltaic cells to convert sunlight directly into electricity. Solar cells made of materials like silicon, cadmium telluride (CdTe) and copper indium gallium selenide (CIGS) are most widely used. Organic photovoltaic cells and dye-sensitized solar cells are emerging technologies. Solar energy harvesting is one of the most abundant and widely implemented renewable energy harvesting systems today powering everything from small electronics to large power plants.

Wind Energy Harvesting
Wind energy harvesting relies on the kinetic energy of wind to produce electricity. Wind turbines with blades rotating a shaft connected to an electric generator are often used to harvest wind energy on larger scales. On smaller scales, micro wind turbines and nanogenerators utilizing phenomena like vortex induced vibrations are being developed. Wind energy harvesting has applications ranging from large wind farms to powering remote sensors and equipment.

Salinity Gradient Power
Salinity gradient power harvesting utilizes the difference in salt concentration between freshwater and seawater sources to produce electricity through methods like reverse electrodialysis. As freshwater mixes with seawater, ions flow through selective ion exchange membranes producing a voltage. This renewable resource can power autonomous devices near ocean inlets, estuaries and rivers flowing into seas. Desalination by-product brine is also a potential source for salinity gradient power harvesting.

Kinetic Energy Harvesting
Kinetic energy harvesting scavenges energy from motion and movements and includes harvesting from footfalls, finger tapping, human body motions and motions of rotating or vibrating objects. Piezoelectric and electromagnetic transducers along with mechanisms like springs and masses are used to convert the mechanical energy into electrical energy. Wearable kinetic energy harvesters and those integrated into automotive and manufacturing equipment have wide applications.

How Energy Harvesting Systems Work
The fundamental operating principle across these energy harvesting systems is the same – an energy source is utilized through a transducer which converts the ambient source into electric voltage/current. The four key steps involved are:

1. Energy Source – This could be solar radiation, temperature differences, vibrations, wind, movements etc.

2. Transducer – Piezoelectric, electromagnetic, thermoelectric or photovoltaic materials are used to convert the environmental energy into electrical energy voltage/current.

3. Energy Storage – The produced electricity is stored using capacitors, batteries or supercapacitors for powering electronics.

4. Load – The stored energy is discharged to power small autonomous devices, sensors or recharge transmitters. Modern efficient power management circuits maximize energy captured and delivered.

Applications and Advantages of Energy Harvesting Systems

The diverse energy harvesting technologies enable powering a wide range of applications independently without need for wiring or frequent battery replacement. Some key applications and advantages are:

– Wireless Sensor Networks – Tiny autonomous sensors can be powered with energy harvesting to enable long term remote monitoring without need for battery changes.

– Medical Implants – Miniaturized self-powered medical devices like pacemakers and hormonal pumps using body energy harvesting avoid complex surgery for battery replacement.

– Condition Monitoring – Vibration, stress and structural health of machines, vehicles, buildings can be continuously monitored using energy harvesting sensors with long operational lives.

– Industrial Equipment – Production machinery, oil and gas pipelines can leverage energy from motions and ambient vibrations to power instrumentation without needing electric cables.

– Remote Equipment – Environmental monitoring stations, smart agriculture sensors, communications relays in hard to reach areas can utilize localized energy sources reliably.

– Sustainability – Integrating energy harvesting helps reduce reliance on batteries and grid power bringing down carbon footprint and operational costs for many applications significantly.

*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it