Techno-Economic Evaluation of Solar Harvesting as a Best-Fit Technology for Sustainable Green Building in the Humid Tropics

Abstract

Best-fit criteria in terms of availability, affordability, minimally conflicting operationality, energy efficiency, buildability, and maintainability are the hallmarks of sustainable green building technology. This study evaluates solar harvesting as a best-fit technology for residential buildings in the humid tropics. An analysis of a residential property located in Port Harcourt, Nigeria, is used as a case study to techno-economically portray the viability of solar harvesting. The analysis is carried out for an off-grid PV system comprising a solar PV array for trapping solar energy; a charge controller to prevent overcharging of batteries; an inverter for converting the DC power from the solar PV arrays to AC power; and deep-cycle lead-acid batteries for power storage. The analysis depicts that the annualized life-cycle cost (ALCC) is much lesser compared to annual electricity bills paid, even after adjustment for power consumption by appliances excluded in the analysis. This cost reduction is further amplified when the additional costs and health risks associated with power generation from diesel generator sets are considered. The study demonstrates that potential gains could be made if policy measures/mechanisms for trading excess power to the national grid are put in place. Such measures would eliminate the need for battery storage thus significantly reducing the initial capital outlay/replacement costs for solar harvesting. The study thus buttresses the techno-economic viability of solar harvesting as a best-fit technological option for buildings located in the humid tropics. Keywords: Best-fit Technology, Green Building, Solar Harvesting; Sustainability, Humid Tropics