Wang Yigang has designed flow, a wind solar energy system. This solar and wind energy collection system uses arciform photovoltaic cells to enable a better collection of sun light. At the same time, the shell, which is composed of six photovoltaic cells, can be used as wind concentrator. The wind forms a whirlpool within. This acceleration of wind speed increases the performance of the rotor. Through movable joints, the angles of the photovoltaic cells can be adjusted so that different orientations can be made for the maximisation of sun exposure, and to vary the amount of wind entering the system. The wind energy system uses a Darrieus-type vertical axis wind turbine. It can operate normally even when the wind is not very strong. In addition, FLOW?s small size makes this system suitable for family use.