The invention belongs to the technical field of hot
air drying of agricultural and sideline products, and discloses a multi-stage
heat pump drying and dehumidifying
system with a bypass pipeline. Thesystem comprises a
control unit, a main
air channel and a
drying chamber which is used for containing to-be-dried materials; an air supply inlet for introducing air and an air exhaust outlet for discharging the air are formed in the
drying chamber; the two ends of the main
air channel are communicated with the air supply inlet and the air exhaust outlet respectively, and the main
air channel is internally provided with a main blower, a dehumidifying chamber, a water baffler and a heating chamber, wherein the dehumidifying chamber, the water baffler and the heating chamber are sequentially arranged in the air flow direction; the multi-stage
heat pump drying and dehumidifying
system further comprises a multi-stage
heat pump unit and the bypass pipeline which is communicated with the dehumidifying chamber, and multi-stage heating and multi-stage humidifying are achieved. Compared with a single-stage heat pump drying
system, the pressure ratio of a compressor is reduced, the efficiency ofthe compressor is improved, and the
air volume control based on the bypass pipeline effectively adjusts the humidifying performance of the system, so that the system has a wider adjusting range.