A heat pump dryer, comprising:
- a main casing having an air inlet, an air outlet, a heat exchanging compartment, a partitioning member provided in said heat exchanging compartment to divide said heat exchanging compartment into an air inlet channel and an air outlet channel, said air inlet channel communicating with said air inlet while said air outlet channel communicating with said air outlet, said air inlet channel communicating with said air outlet channel through an air passage formed in said heat exchanging compartment;
- a plurality of connecting pipes for allowing heat exchange medium to pass therethrough;
- a four-way reversing valve, said four-way reversing valve having first through fourth communicative ports, wherein said first communicative port selectively communicates with said second communicative port, while said third communicative port selectively communicating with said fourth communicative port;
- a compressor having a compressor input port and a compressor output port;
- a first heat exchanger connected to said compressor through at least one of said connecting pipes and said four-way reversing valve, said first heat exchanger having a first connection port and a second connection port, and is positioned in said air inlet channel;
- and
- a second heat exchanger connected to said compressor and said first heat exchanger through at least one of said connecting pipes and said four-way reversing valve, said second heat exchanger having a third connection port and a fourth connection port, and is positioned in said air outlet channel;
- a fan provided in said air inlet channel;
- and
- a energy efficient heat exchanger provided in said heat exchanging compartment of said main casing, said energy efficient heat exchanger having a first portion partially exposed to said air inlet channel, and a second portion partially exposed to said air outlet channel,
- wherein air from a drying compartment is arranged to enter said air inlet channel through said air inlet to sequentially perform heat exchange with said first portion of said energy efficient heat exchanger and said first heat exchanger for extracting heat to said first portion of said energy efficient heat exchanger and said first heat exchanger, said air passing through said air inlet channel being arranged to enter said air outlet channel through said air passage and sequentially perform heat exchange with said second portion of said energy efficient heat exchanger and said second heat exchanger for absorbing heat from said second portion of said energy efficient heat exchanger and said second heat exchanger, said air in said air outlet channel being guided to flow out of said heat pump dryer through said air outlet,
- wherein a predetermined amount of refrigerant circulating in said energy efficient heat exchanger in such a manner that refrigerant circulating in said first portion is arranged to absorb heat from said air so as to become gaseous state and flow to the second portion where said refrigerant is arranged to release heat to said air and return to liquid state.