Research Article
Characterization of Local Nano-Heat Transfer Fluids for Solar Thermal Collection
Table 3
Temperature efficiencies of nanofluids at average operational temperatures.
| Oil-based copper nano-heat transfer fluids fluid | Average temperature of operation (°C) | Temperature efficiency (%) |
| Unused engine oil | 394.1 | 93.4 | Used engine oil | 365.6 | 83.9 | Coconut oil | 297.9 | 79.6 | Sunflower oil | 275.4 | 70.6 | Castor oil | 219.7 | 64.4 |
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