An air conditioner includes: a heat-source-side unit including a compressor and a heat-source-side heat exchanger; use-side units each including a use-side heat exchanger; an intermediate unit that causes the use-side heat exchanger of each of the use-side units to individually function as an evaporator or a radiator of a refrigerant; and two connection pipes that each connect the heat-source-side unit and the intermediate unit. The intermediate unit includes: an ejector that is configured to pressurize the refrigerant evaporated in the use-side heat exchanger that functions as the evaporator by using a driving flow; and a gas-liquid separator into which the refrigerant flowing out from the ejector flows.

An air conditioner includes: a heat-source-side unit including a compressor and a heat-source-side heat exchanger; use-side units each including a use-side heat exchanger; an intermediate unit that causes the use-side heat exchanger of each of the use-side units to individually function as an evaporator or a radiator of a refrigerant; and two connection pipes that each connect the heat-source-side unit and the intermediate unit. The intermediate unit includes: an ejector that is configured to pressurize the refrigerant evaporated in the use-side heat exchanger that functions as the evaporator by using a driving flow; and a gas-liquid separator into which the refrigerant flowing out from the ejector flows.

A water heating system includes: a refrigerant circuit that includes a compressor and in which a refrigerant flows; and a water circuit in which water flows. The refrigerant circuit shares with the water circuit a water heat exchanger that heats the water using the refrigerant discharged from the compressor. The water heat exchanger includes a first heat-exchanging unit in which the refrigerant exchanges heat with the water at a water outlet portion. The refrigerant circuit further includes a heat radiator that is disposed between the compressor and the first heat-exchanging unit and that radiates heat of the refrigerant discharged from the compressor. The heat radiator is configured to radiate heat of the refrigerant to water that flows on an upstream side of the water outlet portion.

A water heating system includes: a refrigerant circuit that includes a compressor and in which a refrigerant flows; and a water circuit in which water flows. The refrigerant circuit shares with the water circuit a water heat exchanger that heats the water using the refrigerant discharged from the compressor. The water heat exchanger includes a first heat-exchanging unit in which the refrigerant exchanges heat with the water at a water outlet portion. The refrigerant circuit further includes a heat radiator that is disposed between the compressor and the first heat-exchanging unit and that radiates heat of the refrigerant discharged from the compressor. The heat radiator is configured to radiate heat of the refrigerant to water that flows on an upstream side of the water outlet portion.

Disclosed is an air conditioner. The air conditioner of the present disclosure for achieving the above or other object, there is provided an air conditioner including: a compressor which compresses refrigerant; an accumulator which supplies refrigerant to the compressor; a condenser which condenses refrigerant discharged from the compressor; an expansion valve which expands refrigerant passing through the condenser; an evaporator which has a heat exchange pipe through which refrigerant passing through the expansion valve flows, and evaporates refrigerant flowing through the heat exchange pipe; a gas-liquid separation pipe which connects a first point and a second point located between one end and the other end of the heat exchange pipe; and a bypass pipe which has one end connected to the gas-liquid separation pipe and the other end connected to the accumulator, wherein the gas-liquid separation pipe comprises: a first part which has one end connected to the first point and the other end connected to one end of the bypass pipe; and a second part which extends from the first part at between one end and the other end of the first part, and is connected to the second point.

A heat transfer method uses a heat transfer system including: a heat source unit in which heat is exchanged between a heat transfer medium and a heat source; a utilization unit in which heat is exchanged between the heat transfer medium and a temperature adjustment target; and a first flow path and a second flow path that connect the heat source unit and the utilization unit. The heat transfer medium flows through the first flow path from the heat source unit to the utilization unit, and flows through the second flow path from the utilization unit to the heat source unit. In the heat transfer method, inorganic hydrate slurry, in which an inorganic hydrate that absorbs heat when dissolved in water is mixed with water, is used as the heat transfer medium.

A heat transfer method uses a heat transfer system including: a heat source unit in which heat is exchanged between a heat transfer medium and a heat source; a utilization unit in which heat is exchanged between the heat transfer medium and a temperature adjustment target; and a first flow path and a second flow path that connect the heat source unit and the utilization unit. The heat transfer medium flows through the first flow path from the heat source unit to the utilization unit, and flows through the second flow path from the utilization unit to the heat source unit. In the heat transfer method, inorganic hydrate slurry, in which an inorganic hydrate that absorbs heat when dissolved in water is mixed with water, is used as the heat transfer medium.

A heat pump system and control method thereof. The heat pump system includes: a main flow path with a compressor, a reversing valve, a first heat exchanger, a first throttling device and a second heat exchanger; the heat pump system further includes an ejector comprising a high-pressure fluid inlet, a fluid suction inlet and a fluid outlet, the high-pressure fluid inlet of the ejector is connected between the second heat exchanger and the first throttling device on the main flow path through a second throttling device, the fluid suction inlet of the ejector is connected to the reversing valve, and the fluid outlet of the ejector is connected to a separator, and a gas phase outlet of the separator is connected to the compressor, and a liquid phase outlet of the separator is connected between the first heat exchanger and the first throttling device on the main flow path.

A heat pump system and control method thereof. The heat pump system includes: a main flow path with a compressor, a reversing valve, a first heat exchanger, a first throttling device and a second heat exchanger; the heat pump system further includes an ejector comprising a high-pressure fluid inlet, a fluid suction inlet and a fluid outlet, the high-pressure fluid inlet of the ejector is connected between the second heat exchanger and the first throttling device on the main flow path through a second throttling device, the fluid suction inlet of the ejector is connected to the reversing valve, and the fluid outlet of the ejector is connected to a separator, and a gas phase outlet of the separator is connected to the compressor, and a liquid phase outlet of the separator is connected between the first heat exchanger and the first throttling device on the main flow path.

A flow rate control device according to one embodiment includes: a flowmeter that repeatedly generates a pulse signal based on flow of a fluid discharged from a fluid machine driven by a brushless motor or AC motor, such that a pulse width of the pulse signal is inversely proportional to a flow rate of the fluid; an FV converter that makes frequency-voltage conversion of the pulse signal and generates a voltage value corresponding to the pulse signal; and a controller that changes a frequency of a drive input voltage for driving the brushless motor or AC motor based on a difference between a converted flow rate of the fluid converted based on the voltage value generated by the FV converter and a preset target flow rate.