An air-conditioning apparatus includes: a heat medium cycle circuit; and a heat source side refrigerant cycle circuit in which a compressor, a heat source side heat exchanger, an expansion device, and a heat medium heat exchanger are connected by pipes, wherein the heat source side refrigerant cycle circuit has a bypass pipe, a bypass valve, and a merging portion, the heat medium heat exchanger side pipe having one end connected to the heat medium heat exchanger, the compressor side pipe having one end connected to a heat source side refrigerant suction side of the compressor, and the heat medium heat exchanger side pipe in the merging portion is connected to the compressor side pipe and the bypass pipe with a pipe axis thereof being upwardly inclined relative to a horizontal direction or being oriented upward in a vertical direction when viewed from the merging portion.

An expansion valve having a high valve opening adjustment accuracy includes: a valve housing which is provided with an inlet port allowing a refrigerant from a condenser to pass therethrough and an outlet port allowing a refrigerant toward an evaporator to pass therethrough; a valve body which is driven by a solenoid; a valve seat on which the valve body sits; and an urging member configured to urge the valve body in a valve closing direction, a space is formed on a valve opening direction side of the valve body, and the refrigerant on the valve closing direction side in relation to the valve body flows into the space.

An expansion valve having a high valve opening adjustment accuracy includes: a valve housing which is provided with an inlet port allowing a refrigerant from a condenser to pass therethrough and an outlet port allowing a refrigerant toward an evaporator to pass therethrough; a valve body which is driven by a solenoid; a valve seat on which the valve body sits; and an urging member configured to urge the valve body in a valve closing direction, a space is formed on a valve opening direction side of the valve body, and the refrigerant on the valve closing direction side in relation to the valve body flows into the space.

A throttling device, including a tank for accommodating liquid refrigerant, with an orifice plate arranged at an outlet of the tank; a floating ball capable of floating on a liquid surface of the refrigerant; a pivot rod pivotally fixed on the tank through a pivot shaft; a connecting rod, with one end thereof fixedly connected with the floating ball, and the other end thereof fixedly connected with the pivot rod; a valve plate fixed on the pivot rod and located near an orifice of the orifice plate, wherein the valve plate is capable of adjusting a flow area of the orifice under the action of the pivot rod; and a limit piece located above the valve plate and being movable to limit the valve plate.

A primary refrigerant circuit allows circulation of a primary refrigerant and includes a primary compressor, a cascade heat exchanger, a primary heat exchanger, and a primary switching mechanism. A secondary refrigerant circuit allows circulation of a secondary refrigerant and includes a secondary compressor, the cascade heat exchanger, and a utilization heat exchanger; and an indoor fan configured to supply air to exchange heat with the secondary refrigerant flowing in the utilization heat exchanger When a defrosting condition is satisfied during normal operation, the primary refrigerant circulates in the order of the primary compressor, the primary heat exchanger, and the cascade heat exchanger after the indoor fan is stopped and the secondary compressor is operated.

A primary refrigerant circuit allows circulation of a primary refrigerant and includes a primary compressor, a cascade heat exchanger, a primary heat exchanger, and a primary switching mechanism. A secondary refrigerant circuit allows circulation of a secondary refrigerant and includes a secondary compressor, the cascade heat exchanger, and a utilization heat exchanger; and an indoor fan configured to supply air to exchange heat with the secondary refrigerant flowing in the utilization heat exchanger When a defrosting condition is satisfied during normal operation, the primary refrigerant circulates in the order of the primary compressor, the primary heat exchanger, and the cascade heat exchanger after the indoor fan is stopped and the secondary compressor is operated.