The invention provides a
heat pump drying system which comprises a compressor, a condenser, a throttling component, an
evaporator, a
drying chamber, a backheating
heat exchanger and a draught fan. Anoutlet of the compressor is connected with a hot end inlet of the condenser, a hot end outlet of the condenser is connected with a cold end inlet of the
evaporator through the throttling component, and a cold end outlet of the
evaporator is connected with an inlet of the compressor; a cold end inlet of the backheating
heat exchanger inputs air acted by the draught fan, a cold end outlet of the backheating
heat exchanger is connected with a cold end inlet of the condenser, a cold end outlet of the condenser is connected with an inlet of the
drying chamber, an outlet of the drying chamber is connected with a hot end inlet of the backheating heat exchanger, a hot end outlet of the backheating heat exchanger is connected with an inlet of the draught fan, and an outlet of the draught fan is communicated with the outside. By means of the
heat pump drying
system, the backheating heat exchanger is used for achieving temperature recovering of air discharged from the drying chamber, the temperature of air entering the cold end evaporator is decreased, the temperature of air entering the hot end condenser is increased, the heat exchange
temperature difference can be effectively reduced, coldand heat end heat exchange is improved, and the
system efficiency is improved.