Heat pump, comprising: an evaporator with an evaporator inlet and an evaporator outlet; a condenser with a condenser inlet and a condenser outlet; a temperature raiser for raising a temperature of an evaporated operating liquid; a switching means (24, 26, 27, 28, 94, 96) for operating the heat pump in a first operating mode or a second different operating mode, wherein the first operating mode is a free cooling mode or a bypass mode and wherein the second operating mode is the free cooling mode or a normal mode, wherein if the first operating mode is the bypass mode, the second operating mode is the free cooling mode or the normal mode, and wherein if the first operating mode is the free cooling mode, the second operating mode is the normal mode; a temperature sensor means for detecting a temperature with regard to the evaporator or the condenser; and a control for providing a control signal based on the detected temperature to the temperature raiser when the heat pump is operated in the second operating mode and for providing a control signal based on the detected temperature to a control output that can be connected to a control input of a heat dissipation device of a region to be heated when the heat pump is operated in the first operating mode, wherein the switching means is configured to connect, in the bypass mode, a return of a region to be cooled to a forward of the region to be heated and to connect a return of the region to be heated to a forward of the region to be cooled, or wherein the switching means is configured to connect, in the free cooling mode, the return (15a, 15c) of the region to be cooled to the condenser inlet and to connect the return (17b, 17d) of the region to be heated to the evaporator inlet, or wherein the switching means is configured to connect, in the normal mode, the return (15a, 15c) of the region to be cooled to the evaporator inlet and to connect the return (17b, 17d) of the region to be heated to the condenser inlet. an evaporator with an evaporator inlet and an evaporator outlet; a condenser with a condenser inlet and a condenser outlet; a temperature raiser for raising a temperature of an evaporated operating liquid; a switching means (24, 26, 27, 28, 94, 96) for operating the heat pump in a first operating mode or a second different operating mode, wherein the first operating mode is a free cooling mode or a bypass mode and wherein the second operating mode is the free cooling mode or a normal mode, wherein if the first operating mode is the bypass mode, the second operating mode is the free cooling mode or the normal mode, and wherein if the first operating mode is the free cooling mode, the second operating mode is the normal mode; a temperature sensor means for detecting a temperature with regard to the evaporator or the condenser; and a control for providing a control signal based on the detected temperature to the temperature raiser when the heat pump is operated in the second operating mode and for providing a control signal based on the detected temperature to a control output that can be connected to a control input of a heat dissipation device of a region to be heated when the heat pump is operated in the first operating mode, wherein the switching means is configured to connect, in the bypass mode, a return of a region to be cooled to a forward of the region to be heated and to connect a return of the region to be heated to a forward of the region to be cooled, or wherein the switching means is configured to connect, in the free cooling mode, the return (15a, 15c) of the region to be cooled to the condenser inlet and to connect the return (17b, 17d) of the region to be heated to the evaporator inlet, or wherein the switching means is configured to connect, in the normal mode, the return (15a, 15c) of the region to be cooled to the evaporator inlet and to connect the return (17b, 17d) of the region to be heated to the condenser inlet.