NOVELTY - A severe cold region solar methane generation pit antifreezing system comprises solar collector (1), automatic vent valve (2), heating coil (4), circulating pump (7), water check valve (8), draining pump, water storage tank, gas-guide tube and charging pump. The automatic vent valve is installed on water circulating pipeline at water outlet of solar collector. The gas-guide tube is installed on water storage tank. The water outlet of circulating pump is connected with water inlet of solar collector.    USE - A severe cold region solar methane generation pit antifreezing system.    ADVANTAGE - The antifreezing system has good heat exchange effect, low system cost and low energy consumption.    DETAILED DESCRIPTION - The severe cold region solar methane generation pit antifreezing system comprises solar collector (1), automatic vent valve (2), heating coil (4), circulating pump (7), water check valve (8), draining pump, water storage tank, gas-guide tube and charging pump. The automatic vent valve is installed on water circulating pipeline at water outlet of solar collector. The gas-guide tube is installed on water storage tank. The water outlet of circulating pump is connected with water inlet of solar collector. The water check valve is installed on water circulating pipeline between water outlet of circulating pump and water inlet of solar collector. The water outlets of both solar collector and charging pump are connected with water inlet of heating coil. The water inlets of both circulating pump and draining pump are connected with water outlet of heating coil. The water inlet of charging pump is connected with water outlet of water storage tank. The water outlet of draining pump is connected with water inlet of water storage tank.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating a severe cold region solar methane generation pit antifreezing system.    Solar collector (1)    Automatic vent valve (2)    Heating coil (4)    Circulating pump (7)    Water check valve (8)