A simulation-based efficiency comparison of AC and DC power distribution networks in commercial buildings. (15th January 2018)

• Record Type: Journal Article
• Authors: Gerber, Daniel L.; Vossos, Vagelis; Feng, Wei; Marnay, Chris; Nordman, Bruce; Brown, Richard
• Is Part Of: Applied energy. Volume 210(2018)
• Page Start: 1167
• Page End: 1187
• Publication Date: 2018-01-15
• Subjects: Commercial buildings -- Efficiency -- Direct current -- Simulation -- Modelica; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2017.05.179
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: Building models with AC and DC distribution are simulated in Modelica and compared. Better models for PV, storage, load, converters, and wiring than in previous works. Parametric simulations reveal the conditions when DC is favorable, and by how much. Buildings with large PV and battery capacity have >11% efficiency savings with DC. Zero Net Energy and islanding microgrid buildings should definitely use DC. Abstract: Direct current (DC) power distribution has recently gained traction in buildings research due to the proliferation of on-site electricity generation and battery storage, and an increasing prevalence of internal DC loads. The research discussed in this paper uses Modelica-based simulation to compare the efficiency of DC building power distribution with an equivalent alternating current (AC) distribution. The buildings are all modeled with solar generation, battery storage, and loads that are representative of the most efficient building technology. A variety of parametric simulations determine how and when DC distribution proves advantageous. These simulations also validate previous studies that use simpler approaches and arithmetic efficiency models. This work shows that using DC distribution can be considerably more efficient: a medium sized office building using DC distribution has an expected baseline of 12% savings, but may also save up to 18%. In these results, the baseline simulation parameters are for a zero net energy (ZNE) building that can island as a microgrid. DC is most advantageous in buildings with large solar capacity, large battery capacity, and high voltage distribution.