While distribution systems deliver power to buildings using alternating current (AC), the loads in commercial buildings have increasingly shifted to those using direct current (DC) power. In addition, on-site generation, such as rooftop solar (which provides a DC source of electricity), is becoming more common in commercial buildings. As a consequence, numerous DC-to-AC and AC-to-DC conversions occur in commercial buildings, each of which results in wasted energy. This makes converting building electrical systems from AC to DC power an attractive energy efficiency measure. In the present study, barriers and advantages of DC power in commercial buildings were examined by interviewing personnel who worked on four commercial construction projects in Colorado. The cases, two new construction and two retrofits, varied in their level of successful implementation. The participants included general contractors, facilities managers, engineers, and financial officers. Interviews were coded for statements about people, technology, and the construction process. The results revealed that successful implementation required an owner who championed the project, along with a team that demonstrated positive motivations (e.g., enjoying a challenge, accepting uncertainty). Technological issues faced by the projects were largely due to limited availability and incompatibility of DC parts. Finally, pre-construction processes (financing, bidding, and contracting) emerged as important differentiators between successful and unsuccessful projects. These findings provide a roadmap for increasing successful implementation of DC power in commercial construction projects.

尽管配电系统使用交流（AC）为建筑物供电，但商业建筑中的负载已逐渐转移到使用直流（DC）电源的负载中。此外，在商业建筑中，诸如屋顶太阳能（提供直流电）的现场发电正变得越来越普遍。结果，在商业建筑中发生了许多直流到交流和交流到直流转换，每一次转换都浪费了能源。这使得将建筑电气系统从交流电转换为直流电成为一项有吸引力的节能措施。在本研究中，采访了科罗拉多州四个商业建筑项目的工作人员，考察了商业建筑中直流电源的障碍和优势。案例，两个新结构和两个改造，成功实施的程度各不相同。参加人员包括总承包商，设施经理，工程师和财务人员。访谈被编码为有关人员，技术和施工过程的陈述。结果表明，成功的实施需要一个拥护该项目的所有者以及一个表现出积极动机（例如，享受挑战，接受不确定性）的团队。项目面临的技术问题主要是由于直流部件的可用性有限和不兼容。最后，施工前的过程（融资，招标和签约）成为成功和失败项目之间的重要区别。这些发现为增加在商业建筑项目中成功实施直流电源提供了一个路线图。