Research Article
Environmental Life-Cycle Analysis of Hybrid Solar Photovoltaic/Thermal Systems for Use in Hong Kong
Table 6
Evaluation of cost payback time.
| Investment: HK$ | Free-stand PV/T [6] | BiPV/T [7] |
| Water storage tank | 400 | 750 | Collector frame and support | 400 | 1800 | Modular thermal absorber | 600 | 2700 | Solar cells and encapsulation | 4000 | 17500 | Inverter | 700 | 1000 | Piping, wiring and accessories | 300 | 900 | Installation costs | 1500 | 3000 |
| Total system costs (HK$) | 7900 | 27650 |
| Useful energy savings | MJ (kWh) | MJ (kWh) |
| Thermal energy | 2650.4 (736.2) | 8127.5 (2257.6) | Electrical energy | 473.2 (131.4) | 1162.4 (322.9) | Space cooling load | — | 742.6 (206.3) |
| Cost savings: HK$ | | |
| Gaseous fuel at HK$0.2/MJ | 530.1 | 1625.5 | Electricity at HK$0.95/kWh | 124.9 | 372.0 | Annual saving | 655.0 | 1997.5 |
| Cost payback time (CPBT) | 12.1 years | 13.8 years |
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Note: USD1 is equivalent to HK$7.8.
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