There are currently increasingly more loads in buildings requiring direct current (DC) power supply, such as wireless power chargers, inverter airconditioners, computers, LED lighting, electric vehicles. In addition, renewable energy source such as photovoltaic power is becoming more accessible.However, the existing building power distribution system is based on alternating current (AC) system, the power efficiency is reduced by theconversion from DC to AC then AC to DC. From the perspective of source-side in the building energy system, if DC power is directly fed to DC bus,much power loss can be reduced. Moreover, from the perspective of sink-side, as the voltage is adjustable in the DC distribution, if a flexible consumingscheme can be applied to the household appliances, energy efficiency can be greatly improved.

To address this issue, this study aims to investigate the flexibility range of the main energy-consuming home appliances (air conditioners and lightings) inDC networks by experiments. The experiments were conducted in a container house with a pure DC energy distribution network. In the test, the airconditioner is adjusted at different levels to monitor the changes of power and the condition of thermal comfort. As for the lighting, the voltage of LEDlight bulb is adjusted to measure the power and luminance. Through the experiments, a database is established to demonstrate the flexibilitycapacity of these electric appliances. The obtained results can serve as a foundation to support the energy-saving control of flexible DC distributionsystem in the design and operation phases.