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

During operation of a compressor, an indoor heat exchanger operates as a condenser, a first valve between a second junction portion and a refrigerant flow switching device is closed, and a second valve in a bypass pipe connecting a first junction portion and the second junction portion is opened, a refrigeration cycle apparatus detects an abnormality when a temperature obtained by subtracting a temperature of refrigerant at a gas portion of the indoor heat exchanger measured by a third temperature sensor from a saturation temperature obtained by converting a condensing pressure of the refrigerant is larger than a first threshold temperature, or when a temperature obtained by subtracting a temperature in a room measured by a first temperature sensor from a temperature of refrigerant at a liquid portion of the indoor heat exchanger measured by a second temperature sensor is smaller than a second threshold temperature.

A refrigeration cycle apparatus includes a heat source unit configured to supply refrigerant, a first distribution unit and a second distribution unit respectively connected to the heat source unit, and a distribution pipe located between the heat source unit and the first distribution unit and the second distribution unit for distributing the refrigerant flowing from the heat source unit into the first distribution unit and the second distribution unit. Further, the first distribution unit and the second distribution unit individually include a heat exchanger configured to serve as a condenser. Further, if the refrigerant flowing through the distribution pipe is unevenly distributed into the first distribution unit and the second distribution unit, a degree of subcooling at an outlet of the heat exchanger of one of the first distribution unit and the second distribution unit of which the distributed refrigerant is of high quality is increased.

An air conditioner includes two cut-off valves connected to respective refrigerant flow paths. At least one of the two cut-off valves is configured as a flow path switching valve configured to switch a flow path so as to block the refrigerant flow paths when a refrigerant leaks in a utilization circuit.

The present application provides an outdoor unit and a heat pump system. The outdoor unit includes a compressor, a valve assembly, an outdoor heat exchanger, a first pipeline port and a second pipeline port; a first branch that connects the valve assembly and the first pipeline port, the first branch being provided with the outdoor heat exchanger and a first switch valve assembly; a second branch that connects the mode switch valve assembly and the first pipeline port, wherein the second branch is provided with a second switch valve assembly; a third branch that connects the second pipeline port and the refrigerant inlet of the outdoor heat exchanger. The first and second switch valve assemblies control the on and off of the first branch and the second branch so that the refrigerant flows through the refrigerant inlet and the refrigerant outlet of the outdoor heat exchanger.

There is provided an air conditioner capable of displaying sufficient cooling ability in each indoor unit by allowing a sufficient amount of refrigerant to flow into indoor units where cooling ability cannot be displayed. By executing refrigerant amount balance control, since degrees of opening of indoor expansion valves are narrowed in indoor units whose refrigerant superheating degrees are smaller than an average refrigerant superheating degree, amounts of refrigerant flowing into the indoor expansion valves are decreased. In the indoor unit where the refrigerant superheating degree is higher than the average refrigerant superheating degree, since refrigerant pressure on a downstream side of the indoor expansion valve is also decreased due to the degrees of opening of the indoor expansion valves being narrowed, the difference in pressure between the upstream side and the downstream side of the indoor expansion valve increases and an amount of refrigerant flowing into the indoor unit is increased.

An intelligent heat pump system having a dual heat exchanger structure includes a heat source side heat exchange member, a heat pump, an external expansion valve, a refrigerant-water heat exchanger, a heat storage tank, and a target side end unit. A refrigerant flows through the heat pump, the refrigerant-water heat exchanger, and the target side end unit, and in a non-air-conditioning state for the target site, circulates between the heat pump and the refrigerant-water heat exchanger, so that cooled or heated water is stored in the heat storage tank. In an air-conditioning state for the target site, the heat pump and the heat storage tank supply cooling and heating to the target site, so that the power consumption for normal operation is reduced in order to improve the operation efficiency of the intelligent heat pump system.

An air conditioning apparatus may include an outdoor unit through which a first fluid, such as refrigerant circulates, an indoor unit through which a second fluid, such as water circulates, a heat exchange device which is configured to connect the outdoor unit to the indoor unit and in which the first fluid and the second fluid are heat-exchanged with each other, a first inner tube which is configured to connect the outdoor unit to the heat exchange device and through which the first fluid at high-pressure flows, a second inner tube which is configured to connect the outdoor unit to the heat exchange device and through which the first fluid at low-pressure flows, and a third inner tube which is configured to connect the outdoor unit to the heat exchange device and through which the first fluid in liquid form flows. The heat exchange device may include a bypass tube configured to bypass the second inner tube and a flow control valve provided in the bypass tube.

An air conditioning apparatus is provided that may include an outdoor unit including a compressor and an outdoor heat exchanger and through which a refrigerant is circulated, an indoor unit through which a fluid, such as water is circulated, and at least one heat exchange device including a heat exchanger in which the refrigerant and the fluid are heat-exchanged with each other. The at least one heat exchange device may include a high-pressure guide tube that extends from a high-pressure gas tube of the outdoor unit so as to be connected to a first side of the heat exchanger, a low-pressure guide tube that extends from a low-pressure gas tube of the outdoor unit so as to be combined with the high-pressure guide tube, a liquid guide tube that extends from a liquid tube of the outdoor unit so as to be connected to a second side of the heat exchanger, and a solenoid valve installed in the high-pressure guide tube or the low-pressure guide tube to perform an opening and closing operation so as to allow the refrigerant to flow in a first direction. The high-pressure gas tube and the low-pressure gas tube may be connected to each other by a single gas tube, and when the indoor unit performs a cooling operation or a heating operation, flow of refrigerant in the first direction may be blocked in a state in which power is applied to the solenoid valve.

A HVAC system that includes a compressor comprising a suction port and a discharge port. Also included is a refrigerant circulating throughout the HVAC system and through the compressor. Further included is a pressure equalization valve fluidly coupling the discharge port of the compressor with the suction port of the compressor, the pressure equalization valve configured to open while the compressor is operating.