NOVELTY - A dual heat energy warming biogas system comprises a fermentation tank (A), a feeding device (E), a biogas purifying device (D), and a residue processing device (F). The fermentation tank is provided with a feed inlet (E1), a biogas port and an overflow port. The biogas port is communicated with the biogas purifying device via a biogas pipe. The fermentation tank is also provided with a warming device and a stirring device (G). The warming device comprises a solar warming device (B) and an auxiliary heat energy warming device (C).    USE - Dual heat energy warming biogas system.    ADVANTAGE - The system has high density, high temperature, high stirring rate, high gas production rate, low tank body, low investment, low danger and low operation cost, and is energy-saving.    DETAILED DESCRIPTION - A dual heat energy warming biogas system comprises a fermentation tank (A), a feeding device (E), a biogas purifying device (D), and a residue processing device (F). The fermentation tank is provided with a feed inlet (E1), a biogas port and an overflow port. The feed inlet is communicated with the feeding device via a feeding pump. The biogas port is communicated with the biogas purifying device via a biogas pipe. The overflow port is communicated with the residue processing device via an overflow pipe. The fermentation tank is also provided with a warming device and a stirring device (G). The warming device comprises a solar warming device (B) and an auxiliary heat energy warming device (C). The auxiliary heat energy warming device and the solar warming device are circular arc structures. The solar warming device is arranged surrounding the south side wall of fermentation tank body. The auxiliary heat energy warming device is arranged surrounding the north side wall of the fermentation tank body. Top parts of the auxiliary heat energy warming device and solar warming device are provided with a platform. The solar warming device, the auxiliary heat energy warming device, the platform, ground and the side wall of the fermentation tank body form a sealed structure. The color of the side wall of the fermentation tank body is black.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the dual heat energy warming biogas system.    Fermentation tank (A)    Solar warming device (B)    Auxiliary heat energy warming device (C)    Biogas purifying device (D)    Feeding device (E)    Feed inlet (E1)    Residue processing device (F)    Stirring device (G)