An Efficiency Comparison Study for Small Appliances Operating in DC and AC in Minigrids

With the decreased cost of power electronics, many traditionally alternating current (AC) loads have transitioned to use direct current (DC) at point of use. In this study, we compare the efficiency of a sample of common AC/DC power converters and estimate the potential energy consumption for common off-grid loads. Methods are based upon a larger Department of Energy project to characterize miscellaneous electric loads for commercial buildings. Using literature and measurements, we also estimate potential energy savings possible if common productive use appliances could be acquired in DC versions. Finally, we touch on international efforts to develop DC appliances and provide observations on methods required for characterizing energy efficiency.