  Direct Current (DC) power distribution has gained attention in the
Residential Nanogrids (RNGs) due to the substantial increase in the number of
roof-top Photovoltaic (PV) systems and internally DC appliances used in
buildings. Using DC distribution improves the efficiency of the RNGs compared
to AC distribution. This paper investigated the efficiency of a DC RNG for low
and high distribution voltage levels by exploring reasons for power losses. The
studied DC RNG consisted of various types of local loads, on-site PV
generation, and battery storage systems. The realistic load, PV profiles, and
converter efficiency curves were used to make the analysis more accurate. In
addition, three load profiles with low, medium, and high power consumptions
were considered to study the load impacts on the overall system efficiency.
