The invention provides an overlapping-typed
heat pump for extracting heat sectionally, which belongs to the technical field of surplus heat utilization and
heat pump /
refrigeration. According to the disadvantages that an overlapping-typed unit for extracting heat in a
single segment way has low
performance index under the circumstances that the temperature range needed by a heat
consumer is wide, the final temperature is high, etc., the invention provides an overlapping-typed unit for extracting heat sectionally. Either the invention comprises an
evaporator, a compressor, a compound condenser-
evaporator and a throttling valve, and adopts the low-temperature stage
heat pump flow of a first working substance to satisfy the high-temperature stage heating need and the low-temperature section heating for the heat
consumer at the same time, and then comprises the compressor, a condenser, the compound condenser-
evaporator and the throttling valve, and adopts the high-temperature stage heat pump flow of a second working substance to satisfy the high-temperature section heating for the heat
consumer, or the convention forms a new heat pump flow by the condenser as well as the throttling valve which are added, and the relative components of the overlapping-typed unit; a surplus heat medium flows through the evaporator to release heat, and heating mediums extract heat from different temperature stages. The invention decreases
heat transfer temperature difference, increases the
performance index; the invention is more particularly suitable for the occasions of
high heat supply temperature and wide range; and the invention can decrease the
power consumption when being used in
refrigeration.