Table 1.
Distribution and significance of nano-mechanical energy harvesting systems over various renewable energy sources of MEH and categorization concerning output power
| Source | Nano | References | Energy conversion | Input | Output | Efficiency |
|---|---|---|---|---|---|---|
| Road profile | ✓ | [43] | Piezoelectric EH structure | 2–4 mm, 5–10 Hz | 3 mW | – |
| × | [44] | Chessboard sliding plate on the road | – | 66 W | 62.4% | |
| × | [45] | Piezoelectric MEH using road bump | 10–30 km/h, 38–53 kg | 4.1 W | 13% | |
| × | [46] | High-efficiency MEH paver | 80 kg | 12 W | 50% | |
| ✓ | [47] | MEH from multi-directional vibration | 5 km/h | 1.4 mW | – | |
| Railway track vibrations | × | [48] | Electromagnetic energy convertor | 1–2 Hz, 6 mm | 6.5 V | 56% |
| ✓ | [49] | Thermoelectric EH using railway track | – | 317 mW | 60% | |
| ✓ | [50, 51] | Smart railway monitoring system | 10–30 Hz | 548 mW | – | |
| × | [52] | Vibration EH using multi-frequencies | 5.6 Hz | 1.5 W | – | |
| × | [53] | The electromagnetic based EH from the railroad | - | 10–100 W | 74% | |
| Shock absorber vibrations | × | [54] | MEH from hydraulic shock absorber | 5–25 mm, 1–5 Hz | 397 W | 50% |
| × | [55] | Electromagnetic shock absorber EH for railway cars | 2–4 mm, 2–4 Hz | 1.2 W | 68% | |
| × | [56, 57] | Regenerative mechanism for shock absorber | 5–10 mm, 1–3 Hz | 0.5 W | 84% | |
| ✓ | [58] | Self-powered sensor nodes for freight rail transport | 80 km/h | 263 mW | 65% | |
| × | [59] | Energy regenerative shock absorber based MEH | 2.5–7.5 mm, 1–2.5 Hz, | 4.3 W | 55% | |
| Ocean wave | × | [60] | Ocean-wave based energy harvesting mechanism | Wave height of 0.2 m | 63 W | – |
| × | [61] | The floating WEC | 0.8 m, 0.76 Hz | – | 39% | |
| × | [62] | WEC with power take-off mechanism | 8 mm, 3 Hz | – | 67% | |
| ✓ | [63] | Oscillating buoy as WEC | 15 mm, 1.2 Hz | 3 V | 57% | |
| × | [54] | Hydraulic energy regeneration from shock absorbers | 72 km/h | 397 W | 50% | |
| Wind energy | ✓ | [64] | Piezoelectric EH from wind energy | 6.5 m/s | 25 mW | – |
| ✓ | [65] | Wind EH using fibre composites | 7.5 m/s | 0.53 mW | – | |
| ✓ | [66] | High-performance piezoelectric EH for wind energy | 2.1 m/s | 1.2 mW | – | |
| ✓ | [67] | A rotational piezoelectric wind energy harvester | 14 m/s | 160 V, 2566 μW | – | |
| ✓ | [68] | Vibro-impact dielectric wind EH | 4 m/s | 0.72 mW | – | |
| Bio-mechanical energy | ✓ | [69] | Scavenging energy from human motion | 5 Hz | 9 mW | 8% |
| ✓ | [70] | Electromagnetic EH from human movements | 9 km/h | 85 mW | 92% | |
| ✓ | [71] | MEH for ultra-low frequency vibrations | 4 Hz | 5.3 mW | – | |
| × | [72] | A human motion-based vibration energy harvester | 4.8 km/h | 5.1 W | – | |
| ✓ | [73] | Biomechanical energy harvesting pavement | 30 Hz | 300 mW | – |