Overlapped type carbon dioxide air source heat pump

The utility model relates to an overlapped type carbon dioxide air source heat pump. The heat pump comprises a low-temperature stage heating system and a high-temperature stage heating system, and the heat pump is formed by overlapping the two-stage heating systems; the low-temperature stage heating system and the high-temperature stage heating system are connected through a condensation evaporator or a plate type heat exchanger in an overlapping manner; the low-temperature stage working medium CO2 absorbs the heat in the external low-temperature environment and transmits the heat to the high-temperature stage working medium R22, the high-temperature stage working medium R22 is cooled by the using side water in a condenser, and the heat is transmitted to the used side water, and finally, the temperature of the used side water is increased to 45 DEG C; the heat pump provides heat for northern households through a fan coil unit or floor radiation. According to the overlapped type carbon dioxide air source heat pump, the heat pump can heat effectively under the condition that the temperature is -30 DEG C, and the machine set heating energy efficiency ratio is higher than 1.665.