Energy Savings Using Direct Current (DC) from Photovoltaic (PV) System in a Residential Home

The conventional AC nanogrid with photovoltaic (PV) system has suffered from power loss caused by power conversion from DC to AC and back to DC for most of the end use in a typical residential home. To overcome the problem, DC nanogrid is proposed in this paper. Partial and full DC nanogrids are designed and their efficiencies are compared with a full AC nanogird. The simulation study results show that partial DC nanoogrid has 79.2% of overall efficiency while AC nanoogrid has 71.87%. Furthermore, the efficiency is improved to 99.74% for a full DC nanogrid. It proves the less amount of power conditioners used in the system the higher the efficiency can be obtained. Moreover, an economic evaluation is conducted on the proposed two DC nanogrids to investigate whether they are sustainable and feasible. From the simulation studies conducted, it is shown that partial DC nanogrid saves electricity bill and capital cost but full DC nanogrid is not feasible even if it saves electricity bill spectacularly high but it needs extremely expensive capital cost.