An air conditioner that includes a refrigerant circuit connecting a plurality of indoor heat exchangers in parallel and is able to complete collection of refrigerant to the side of an outdoor heat exchanger in a shorter time when the refrigerant has leaked at any indoor heat exchanger is provided. Thus, in the air conditioner according to the present invention, when refrigerant leak is detected by a refrigerant leak sensor provided in an indoor unit and refrigerant leak is not detected by a refrigerant leak sensor provided in an indoor unit, an indoor LEV and a cutoff valve are closed to isolate an indoor heat exchanger of the indoor unit from the refrigerant circuit in a refrigerant pump-down operation. When refrigerant leak is detected by the refrigerant leak sensor and refrigerant leak is not detected by the refrigerant leak sensor, an indoor LEV and a cutoff valve are closed.

Provided are a control method of a heat pump system and a heat pump system. The heat pump system includes a throttling element and a four-way valve. The four-way valve has a first state in a case that the heat pump system operates for refrigerating and a second state in a case that the heat pump system operates for heating. The control method includes that: before the four-way valve is switched from the first state to the second state, A is compared with B, and switching of the state of the four-way valve is controlled and the opening degree of the throttling element is adjusted according to the comparison result, or switching of the state of the four-way valve is controlled according to the comparison result, or the opening degree of the throttling element is adjusted according to the comparison result.

An HVAC system includes a reversing valve configured to receive compressed refrigerant and direct the refrigerant based on an operating mode of the HVAC system. One or more suction-side sensors measure suction-side properties associated with refrigerant provided to an inlet of the compressor. The suction-side properties comprise a suction-side temperature. One or more liquid-side sensors measure liquid-side properties associated with the refrigerant provided from an outlet of the compressor. A controller monitors the suction-side property and liquid-side property. The controller determines whether the suction-side property is greater than the liquid-side property. If the suction-side temperature is greater than the liquid-side temperature, the reversing valve is determined to be in an equalizing configuration. The equalizing configuration corresponds to a configuration in which the refrigerant provided from the outlet of the compressor is directed to the inlet of the compressor without first being directed to other components of the HVAC system.

Provided is a refrigerant cycle apparatus capable of suppressing detects caused by iodine even when a refrigerant containing iodine is used. An air conditioner includes a refrigerant circuit through which a refrigerant containing iodine circulates. The refrigerant circuit includes a component that is in contact with a refrigerant containing iodine, the component being made of metal other than aluminum or an aluminum alloy, or having a content of aluminum which is equal to or less than a ratio at which corrosion of aluminum occurs by iodine. The component is at least one of a component of a compressor, a component of a heat-source-side heat exchanger or a utilization-side heat exchanger, a component of an expansion valve, a drier, and a connection pipe.

An air conditioning system, including a compressor, two outdoor heat exchange units, a liquid pipe used for communicating with indoor units, a high-pressure gas tube and a low-pressure gas tube; the air conditioning system further includes a valve assembly. One outdoor heat exchange unit has a first state in which one end thereof communicates with the high-pressure gas tube and another end thereof communicates with the liquid pipe, and has a second state in which one end thereof communicates with the low-pressure gas tube and the other end thereof communicates with the liquid pipe. Further disclosed is a control method for the air conditioning system.

There is provided a refrigerant cycle apparatus capable of suppressing, even when a refrigerant containing CF.sub.3I is used, corrosion of a component of a refrigerant circuit due to the refrigerant containing CF.sub.3I. A refrigerant cycle apparatus includes a refrigerant circuit in which a refrigerant containing CF.sub.3I circulates, the refrigerant circuit including a compressor, an expansion valve, an outdoor heat exchanger, and an indoor heat exchanger that are connected to each other. The refrigerant circuit includes a component to be in contact with the refrigerant. At least a surface of the component to be in contact with the refrigerant is formed by a corrosion resistance material that contains at least one or more selected from a metal in which the percentage of zinc is 10 wt % or less, a resin other than nylon 66, and carbon.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

An HVAC system includes a reversing valve configured to receive refrigerant and direct the received refrigerant based on an operating mode of the HVAC system. A sensor measures a heat-exchanger temperature associated with an outdoor heat exchanger. A controller monitors an outdoor temperature and the heat-exchanger temperature and compares these temperatures. The controller determines whether the HVAC system is intended to operate in a cooling or heating mode. If the heat-exchanger temperature is less than the outdoor temperature and the HVAC system is intended to operate in the cooling mode, the controller determines that a first reversing-valve fault is detected. The first reversing-valve fault is associated with the reversing valve being in the heating configuration when the HVAC system is intended to operate in the cooling mode.

A refrigeration cycle system includes a refrigeration cycle apparatus, an operation signal transmitter, a detection unit, a notification unit, and a processing unit. The refrigeration cycle apparatus includes a refrigerant circuit. The operation signal transmitter transmits an operation signal for the refrigeration cycle apparatus. The detection unit detects leakage of a refrigerant. The notification unit notifies of leakage of the refrigerant by emitting at least one of sound and light in a case in which the detection unit has detected leakage of the refrigerant. The processing unit causes the notification unit to execute test behavior of emitting at least one of sound and light in a case in which the operation signal transmitter transmits the operation signal to the refrigeration cycle apparatus.

A configuration management system for a heating, ventilation, and air conditioning (HVAC) system includes a controller having a memory storing a baseline configuration of the HVAC system. The baseline configuration of the HVAC system indicates that the HVAC system is an air conditioning system or a heat pump system. Additionally, the controller is configured to determine a current configuration of the HVAC system based on detecting whether a reversing valve is present in the HVAC system. The current configuration of the HVAC system includes an air conditioning system configuration or a heat pump system configuration. The controller is also configured to perform a control action in response to determining that the current configuration is different than the baseline configuration.