Cascade heat pump and method for heating or cooling a coolant by means of a cascade heat pump

A cascade heat pump comprising n stages where n≥2, each of the n stages comprising:

• a heat pump with a coolant inlet, a first coolant outlet and a second coolant outlet,
• wherein the heat pump has a hot side and a cold side and a flow divider,
• wherein the flow divider divides a coolant flow entering the coolant inlet into partial flows between the hot side and the cold side,
• wherein the first coolant outlet of the heat pump of each stage i, where i=1 . . . n−1, is connected to the coolant inlet of the heat pump of a subsequent stage i+1, such that a first partial flow of the coolant is provided from the first coolant outlet of the heat pump of each stage i, where i=1 . . . n−1, to the coolant inlet of the heat pump of the subsequent stage i+1, and
• wherein the second coolant outlet of the heat pump of at least one subsequent stage i+1, where i=1 . . . n−1, is connected via a recirculation line to the coolant inlet of the heat pump of a preceding stage 1 . . . i, such that a second partial flow of the coolant is fed from the second coolant outlet of the heat pump of the at least one subsequent stage i+1, where i=1 . . . n−1, to the coolant inlet of the heat pump of the preceding stage 1 . . . i.