A
heat pump having a cooling mode includes a cooling
evaporator coupled to an advance flow and a
backflow. The cooling
evaporator is brought to a pressure such that a
vaporization temperature of the working liquid in the
backflow is below a temperature of an object to be cooled to which the
backflow may be thermally coupled. In this manner, an area having vapor at
high pressure is generated. This vapor is fed into a dynamic-type compressor which outputs the vapor at a low pressure and provides electrical energy in the process. The vapor at low pressure is fed to a cooling liquefier which provides vapor
liquefaction at a low temperature, this temperature being lower than the temperature of the object to be cooled. The working liquid removed from the cooling
evaporator due to the
vaporization is refilled by a filling pump. The
heat pump having a cooling mode also results when a
specific heat pump is operated in the reverse direction, and provides cooling without any net use of electrical energy. Instead, the cooling even generates electrical energy.