Heat recovery system for heating source of vacuum freeze dryer

The invention discloses a heat recovery system for a heating source of a vacuum freeze dryer, and relates to the technical field of vacuum freeze dryers, the heat recovery system comprises a condenser, a compressor, an expansion valve, a cold trap, a vacuum freeze-drying box body, a refrigeration pipe and a heat exchange pipe, the refrigeration pipe is wound in the cold trap, and cooling liquid in the heat exchange pipe circularly flows between the vacuum freeze-drying box body and the condenser. The cold trap is connected with the inner side of the vacuum freeze-drying box body through a connecting pipe, heat exchange is carried out between the cold trap and water vapor sublimated by heated freeze-dried objects in the vacuum freeze-drying box body, and low-grade heat is converted into high-grade heat through the compressor and released to cooling liquid in the condenser. The cooling liquid transfers one part of the high-grade heat energy into the vacuum freeze-drying box body to heat a freeze-dried article,