Table 8.
Key parameters associated with open and closed type cultivating systems
| Parameters | Open system | Closed system |
|---|---|---|
| Area-to-volume ratio | Large (4–10 times higher than closed counterpart) | Small |
| Algal species | Restricted | Flexible |
| Main criteria for species selection | Growth competition | Shear-resistance |
| Population density | Low | High |
| Harvesting efficiency | Low | High |
| Cultivation period | Limited | Extended |
| Contamination | Possible | Unlikely |
| Water loss through evaporation | Possible | Prevented |
| Light utilization efficiency | Poor/fair | Fair/excellent |
| Gas transfer | Poor | Fair |
| Temperature control | None | Excellent |
| Most costly parameters | Mixing | Oxygen control, temperature control |
| Capital investment | Small | High |