Dishwasher with heat pump

A method for operating a dishwasher comprising a tub, a heat pump, and a sump for collecting washing liquid, the method comprising:

• operating the heat pump in a washing cycle in a reverse mode and circulating washing liquid from an inlet at the sump through a lower spray device and/or outlet at a bottom of the tub for supplying cooled washing liquid into an interior of the tub and from there back into the sump via the tub,
• wherein the heat pump comprises a compressor, an evaporator, a condenser, an expansion device, and a refrigerant flow changing device adapted to change between a normal mode of the heat pump and the reverse mode of the heat pump, wherein the condenser comprises a first passage and a second passage in heat-exchanging contact with each other,
• wherein the dishwasher further comprises a heat exchanging medium in heat exchanging contact with the evaporator and a washing fluid conduit system comprising a first washing fluid supply conduit terminating at an outlet connected to the lower spray device,
• wherein, in the normal mode of the heat pump, the condenser is adapted to heat the washing liquid when the washing liquid is circulated through the first passage of the condenser and the evaporator is adapted to cool the heat exchanging medium, and wherein, in the reverse mode of the heat pump, the condenser is adapted to cool the washing liquid and the evaporator is adapted to heat the heat exchanging medium.