The invention provides a two-stage dual-dehumidification-
evaporator and dual-dehumidification-condenser dehumidification
heat pump system which comprises a closed refrigerating
fluid system. The closed refrigerating
fluid system comprises a low-temperature-side compressor, a four-way
reversing valve, a first low-temperature-side dehumidification
heat exchanger, a second low-temperature-side dehumidification
heat exchanger, a low-temperature-side
throttle device, a high-temperature-side compressor, a first three-way
reversing valve, a second three-way
reversing valve a high-temperature-side
throttle device, a first high-temperature-side dehumidification
heat exchanger and a second high-temperature-side dehumidification heat exchanger. The invention further provides a two-stage dual-humidification temperature increase and decrease method. In the
system and the method, the two dehumidification evaporators / condensers connected in parallel at different
evaporation / condensation temperatures are adopted, and treatment air sequentially flows through the high-temperature dehumidification
evaporator and the low-temperature dehumidification
evaporator. Compared with the prior art, according to the
system and the method, the circulating
switching time is prolonged, reliability and economic performance are both improved to a certain degree, and in addition, multi-mode operating can be achieved through switching.