Table 2.
Features and characterization of some previously developed nano-systems to harvest renewable energy from natural resources (wind, ocean and solar resources)
| Energy conversion | Mechanism | Input | Output | Advantages () and disadvantages (↓) |
|---|---|---|---|---|
| Electromagnetic generators (EMG) | Portable wind energy harvester based on S-rotor and H-rotor | 5–12 m/s | 108 mW, 23.2% |
() powers the monitoring sensors in railway tunnels () uses hybrid S-rotor and H-rotor |
| Double-Skin Façade system for harvesting wind energy | 3–8 m/s | 1110 W/m2 |
() low turbulence and uniform flow due to cavity (↑) provides a wide range of angles for incident wind |
|
| Galloping, vortex shedding, flutter, and aerodynamic instability | 2–6 m/s | 1 W |
(↑) based on wake galloping (↑) a simpler mechanism for structural health monitoring system (↑) powers wireless sensors |
|
| Piezoelectric nanogenerators (PENG) | The flutter of a flexible piezoelectric membrane | 9 m/s | 5 mW/cm3 |
(↑) simple inverted flag orientation (↑) Self-aligning capability (↑) can operate in low-speed regimes |
| Vortex-induced vibration-based piezoelectric EH | 1–1.4 m/s | 0.6 mW |
(↑) facilitates Y-shaped attachments on bluff body (↑) provides an enhanced energy harvesting efficiency |
|
| MEH is composed of permanent magnets, rotor, piezoelectric stack, and flexure mechanism | 100 rpm | 0.2 mW |
(↑) simple and compact design (↑) optimal performance with a larger power output |
|
| Pyroelectric (PEG)/ Thermoelectric generators (TEG) | Flexible vortex generator or turbulator | 1–25 m/s | 3 W/cm2 |
(↑) Flexible structure with un-interrupted energy output (↓) possesses low pyroelectric coefficient |
|
Harvesting solar and wind energies using thermal oscillations through sustainable PEG |
2.5–5.3 m/s | 421 W/cm3 |
(↑) provides high power density (↓) power density depends on the intensity of the solar irradiations and wind speed |
|
| Triboelectric nanogenerators (TENG) | A rotary TENG based on mechanical deformation of multiple plates | 15 m/s | 39 W/m2 |
(↑) facilitates the application of polymer nanowires (↑) can be used as a self-powered wind speed sensor |
| TENG-based windmill composed of nanopillar-array architectured layers | 14–15 m/s | 568 V, 26 μA |
(↑) simple and cheap fabrication (↑) high output and optimal performance (↑) high stability |
|
| Pendulum-based TENG using a pendulum structure with high energy conversion efficiency | 2 m/s, 2 Hz | 56 V |
(↑) superior durability (↑) ultrahigh sensitivity (↑) long-time operation (↑) energy harvesting from wave and wind |
The references of the research papers cited in this table are provided in the Additional file 1