An assembly for heat generation, comprising a CO 2 heat pump which includes a fluid inlet and a fluid outlet and for which a maximum fluid inlet temperature is specified, a heat exchanger which includes a fluid inlet and a fluid outlet and whose fluid outlet temperature is higher than the maximum fluid inlet temperature of the CO 2 heat pump, and comprising a fluid/fluid heat pump which includes a first and a second fluid inlet (10, 11) and a cold fluid outlet and a warm fluid outlet, wherein the fluid/fluid heat pump is adapted to supply a first fluid stream entering through the first fluid inlet to the cold fluid outlet and to supply a second fluid stream entering through the second fluid inlet to the warm fluid outlet and thereby withdraw heat from the first fluid stream and pass the same on to the second fluid stream, wherein the CO 2 heat pump, the heat exchanger and the fluid/fluid heat pump can be connected in series in this order in a fluid circuit, wherein a fluid flows through the fluid circuit, the fluid outlet of the heat exchanger is in flow connection with the first fluid inlet of the fluid/fluid heat pump, the fluid/fluid heat pump is adapted to cool the first fluid stream to a temperature which at most is equal to the maximum fluid inlet temperature specified for the CO 2 heat pump, and the cold fluid outlet of the fluid/fluid heat pump is in flow connection with the fluid inlet of the CO 2 heat pump, furthermore comprising a fluid reservoir which includes a first region for storing fluid with a first temperature, a second region for storing fluid with a second temperature, which is higher than the first temperature, and a third region for storing fluid whose temperature lies between the first and the second temperature, wherein each of the three regions includes at least one fluid inlet and at least one fluid outlet, and a fluid inlet of the second region is in flow connection with the fluid outlet of the CO 2 heat pump, characterized in that a fluid inlet of the first region is in flow connection with the cold fluid outlet of the fluid/fluid heat pump and a fluid outlet of the first region is in flow connection with the fluid inlet of the CO 2 heat pump, and a fluid outlet of the second region is in flow connection with the fluid inlet of the heat exchanger, and a fluid inlet of the third region is in flow connection with the fluid outlet of the heat exchanger and a fluid outlet of the third region is in flow connection with the first fluid inlet of the fluid/fluid heat pump. a CO 2 heat pump which includes a fluid inlet and a fluid outlet and for which a maximum fluid inlet temperature is specified, a heat exchanger which includes a fluid inlet and a fluid outlet and whose fluid outlet temperature is higher than the maximum fluid inlet temperature of the CO 2 heat pump, and comprising a fluid/fluid heat pump which includes a first and a second fluid inlet (10, 11) and a cold fluid outlet and a warm fluid outlet, wherein the fluid/fluid heat pump is adapted to supply a first fluid stream entering through the first fluid inlet to the cold fluid outlet and to supply a second fluid stream entering through the second fluid inlet to the warm fluid outlet and thereby withdraw heat from the first fluid stream and pass the same on to the second fluid stream, wherein the CO 2 heat pump, the heat exchanger and the fluid/fluid heat pump can be connected in series in this order in a fluid circuit, wherein a fluid flows through the fluid circuit, the fluid outlet of the heat exchanger is in flow connection with the first fluid inlet of the fluid/fluid heat pump, the fluid/fluid heat pump is adapted to cool the first fluid stream to a temperature which at most is equal to the maximum fluid inlet temperature specified for the CO 2 heat pump, and the cold fluid outlet of the fluid/fluid heat pump is in flow connection with the fluid inlet of the CO 2 heat pump, furthermore comprising a fluid reservoir which includes a first region for storing fluid with a first temperature, a second region for storing fluid with a second temperature, which is higher than the first temperature, and a third region for storing fluid whose temperature lies between the first and the second temperature, wherein each of the three regions includes at least one fluid inlet and at least one fluid outlet, and a fluid inlet of the second region is in flow connection with the fluid outlet of the CO 2 heat pump, characterized in that a fluid inlet of the first region is in flow connection with the cold fluid outlet of the fluid/fluid heat pump and a fluid outlet of the first region is in flow connection with the fluid inlet of the CO 2 heat pump, and a fluid outlet of the second region is in flow connection with the fluid inlet of the heat exchanger, and a fluid inlet of the third region is in flow connection with the fluid outlet of the heat exchanger and a fluid outlet of the third region is in flow connection with the first fluid inlet of the fluid/fluid heat pump.