A switching valve device for switching an intermediate flow path through which a fluid flows from an inlet to an outlet includes: a first valve which switches a flow path extending from the inlet to one of two flow paths; and a second valve which is provided on a downstream side of the first valve and switches the intermediate flow path by a differential pressure generated by depressurization in an external flow path Lout connected to the intermediate flow path connected to one of the two flow paths.

Excessive specifications of a shutoff valve leads to increase in production cost. An air conditioner configured to circulate a lower flammability refrigerant in a refrigerant circuit includes a first shutoff valve and a second shutoff valve configured to inhibit refrigerant leakage into a predetermined space. Each of the first shutoff valve and the second shutoff valve in a shutoff state has a shutoff leakage rate, as an air leakage rate in a case where fluid is air at 20° C. and a differential pressure between upstream and downstream of the valve is 1 MPa, more than 300 (cm.sup.3/min) and less than 300×R (cm.sup.3/min). R satisfies $R=\left({\rho }_{\mathrm{md}}\times V_{\mathrm{md}}\times A_d\right)\text{/}(C_r\times {\left(2\times \Delta P_r\text{/}{\rho }_{1\mathrm{rl}}\right)}^{0.5}\times A_v\times {\rho }_{1\mathrm{rl}}+A_v$

A finless heat exchanger includes two headers and a plurality of heat transfer tubes spaced apart from each other and arranged side by side. The two headers each have a plurality of insertion holes, to which both ends of the heat transfer tubes are fitted and connected. The heat transfer tubes each include straight portions extending in a direction orthogonal to an arrangement direction, in which the heat transfer tubes are arranged, and turning portions. The straight portions and the turning portions are alternately and continuously arranged.

To predict and detect a failure in a compressor provided in an air conditioner, the air conditioner is provided with: a heat exchanger; the compressor; piping connecting the heat exchanger and the compressor with each other; and a control unit controlling the compressor and having a compressor failure predicting and detecting means, and in this air conditioner, the compressor failure predicting and detecting means of the control unit includes: a current detecting part detecting a driving current driving the compressor; a pulsation detecting part detecting pulsation in a driving current detected by the current detecting part; and an anomaly determining part predicting or detecting any failure in the compressor based on a magnitude and a duration of pulsation in a driving current detected by the pulsation detecting part.

An air-conditioning apparatus includes a refrigeration circuit, a first shut-off device, a leakage detection device, and a controller configured to perform a refrigerant recovery operation in a case where refrigerant leakage is detected. At the time of the refrigerant recovery operation, the controller performs control to perform a first operation of recovering refrigerant from a load-side heat exchanger into an accumulator and a heat-source-side heat exchanger, and a second operation of moving refrigerant in the heat-source-side heat exchanger to the accumulator. In the first operation, the first shut-off device is closed, a flow passage switching device is brought into a first connection state, and a compressor is driven. The second operation is performed after the first operation, and in the second operation, the connection state of the flow passage switching device is switched to a second connection state in a state where the compressor is being operated.

Provided is a heat exchanger, including: a refrigerant distributor including: a gas-liquid separating portion having a function of separating a gas-liquid refrigerant mixture into a liquid refrigerant and a gas refrigerant; and a distributing portion provided to the gas-liquid separating portion. A plurality of heat transfer pipes connected to the distributing portion. The plurality of heat transfer pipes are arranged side by side in a first direction, and extend along a second direction intersecting with the first direction. When the refrigerant distributor is viewed along a direction orthogonal to each of the first direction and the second direction, a first space forming portion overlaps a region of the plurality of heat transfer pipes. When the refrigerant distributor and the heat transfer pipes are viewed along the first direction, a clearance is present between the gas-liquid separating portion and the heat transfer pipes.

The present disclosure provides an air conditioner, a control strategy of the air conditioner and an air conditioning system. The air conditioner includes a compressor, a first heat exchanger, a phase-change thermal-storage heat exchanger, a throttling device and a box. The throttling device is provided between the first heat exchanger and the phase-change thermal-storage heat exchanger. One of the first heat exchanger and phase-change thermal-storage heat exchanger functions as an evaporator and the other functions as a condenser. The box includes an air supply port and an air return port. The compressor, the first heat exchanger, the phase-change thermal-storage heat exchanger and the throttling device are mounted in the box, thereby facilitating installation of the air conditioner.

Excessive specifications of a shutoff valve leads to increase in production cost. An air conditioner configured to circulate a lower flammability refrigerant in a refrigerant circuit includes a first shutoff valve and a second shutoff valve configured to inhibit refrigerant leakage into a predetermined space. Each of the first shutoff valve and the second shutoff valve in a shutoff state has a shutoff leakage rate, as an air leakage rate in a case where fluid is air at 20° C. and a differential pressure between upstream and downstream of the valve is 1 MPa, more than 300 (cm.sup.3/min) and less than 300×R (cm.sup.3/min). R satisfies

[00001]$R=\left({\rho }_{\mathrm{md}}\times V_{\mathrm{md}}\times A_d\right)\text{/}\left(C_r\times {\left(2\times \Delta P_r\text{/}{\rho }_{1\mathrm{rl}}\right)}^{0.5}\times A_v\times {\rho }_{1\mathrm{rl}}+A_v\times {\left(2\text{/}\left(\lambda +1\right)\right)}^{\left(\left(\lambda +1\right)\text{/}2\left(\lambda -1\right)\right)}\times {\left(\lambda \times P_{1r}\times {\rho }_{1\mathrm{rg}}\right)}^{0.5}\right).$

The present disclosure provides a multi-air conditioner for heating/cooling operation including: at least one of indoor units for heating/cooling operation including an indoor heat exchanger respectively; and an outdoor unit for heating/cooling operation including a compressor, an outdoor heat exchanger, and a switching unit configured to be disposed in a discharge side of the compressor to switch a flow of refrigerant, wherein the outdoor unit for heating/cooling operation includes a receiver which selectively stores refrigerant or oil according to a cooling or heating operation mode and provides the stored refrigerant or oil to the compressor. Accordingly, in the accumulator of the multi-air conditioner for heating/cooling operation using the receiver, the receiver that is not used in the heating mode can be converted and used for oil storage, thereby preventing oil burnout without adding a structure.

A refrigerant control system includes: a reversing valve including: a first inlet configured to receive refrigerant output from a condenser; a first outlet configured to output refrigerant to an inlet of an evaporator located inside of a building; a second inlet configured to receive refrigerant output from the evaporator; and a second outlet configured to output refrigerant to an inlet of a compressor that pumps refrigerant to the condenser; a reversing module configured to: selectively actuate the reversing valve to a first position such that: refrigerant flows directly from the second inlet to the second outlet; and refrigerant flows directly from the first inlet to the first outlet; and selectively actuate the reversing valve to a second position such that: refrigerant flows directly from the second inlet to the first outlet; and refrigerant flows directly from the first inlet to the second outlet.