A refrigerant leakage determination system capable of detecting leakage of refrigerant without requiring complicated processing is provided. A refrigerant leakage determination system is a refrigerant leakage determination system of a refrigeration cycle apparatus that includes a refrigerant circuit including a heat-source-side heat exchanger and has, as operating modes, a normal mode in which the heat-source-side heat exchanger is caused to function as an evaporator and a defrosting mode in which the heat-source-side heat exchanger frosted during a normal operation is defrosted. The refrigerant leakage determination system includes a processor configured to acquire defrosting information regarding a relationship between a normal operation period and the number of defrosting operations, and memory that stores the defrosting information. The processor is further configured to determine, based on the acquired defrosting information, leakage of refrigerant in the refrigerant circuit.

A notifier notifies a user of a warning when a ratio of first refrigerant is different from a suitable value, the ratio being determined from a first difference between a first temperature and a second temperature and from a second difference between a third temperature and a fourth temperature. The first temperature is a temperature of a non-azeotropic refrigerant mixture between a first heat exchanger and a second heat exchanger. The second temperature is a temperature of the non-azeotropic refrigerant mixture between the second heat exchanger and a first expansion valve. The third temperature is a temperature of the non-azeotropic refrigerant mixture between a first decompressor and a first connecting point. The fourth temperature is a temperature of the non-azeotropic refrigerant mixture between a second decompressor and the first connecting point.

An air-conditioning apparatus includes a load-side heat exchanger including a first heat exchanger disposed on a windward of a second heat exchanger in a direction of an air flow generated by an air-sending device. The air flow passing through the first heat exchanger passes through a second heat exchanger. During cooling operation, a bypass valve causes a part of refrigerant flowing through a first refrigerant pipe to flow through a coupling pipe through a bypass pipe. During heating operation, the bypass valve blocks a flow of the refrigerant flowing from the coupling pipe toward the first refrigerant pipe through the bypass pipe, and causes all of the refrigerant flowing through the coupling pipe to flow from the coupling pipe to the first heat exchanger.

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.

A heat pump that includes a compressing unit having an inlet and an outlet; a condensing unit in fluid communication with the outlet; an evaporating unit in fluid communication with the condensing unit; a variable induction heating unit disposed about a length of conduit fluidically coupling the evaporating unit and the inlet; a reversing valve disposed between the induction heating unit and the evaporating unit; and a metering device (e.g., expansion valve) disposed between the evaporating unit and the condensing unit. Advantageously, the variable induction heating unit may be selectively controllable to enable the heat pump to operate at an ambient temperature of −30 degrees Fahrenheit.

A refrigeration device has a coolant circuit with a compressor, a first evaporator assembly, and a high-pressure tube connected upstream of the first evaporator assembly. A second evaporator assembly is connected in parallel with the first evaporator assembly. A low-pressure tube is connected downstream of the first and second evaporator assemblies. A suction tube heat exchanger has a high-pressure tube section of the high-pressure tube and a low-pressure tube section of the low-pressure tube heat-conductively coupled. The suction tube heat exchanger has three temperature sensors in three positions from a group of positions at the inlet and outlet of the low-pressure tube section, and at the inlet and outlet of the high-pressure tube section. A ratio of the mass flow of coolant to the first evaporator assembly relative to the total mass flow of the coolant can be determined.

A heat pump may include a compressor configured to compress a refrigerant, a first temperature sensor provided in heating pipes connected to a heating device that heats an indoor space to sense a temperature of fluid flowing through the heating pipes, and a controller. The controller may be configured to determine whether a boiler is operating to heat an indoor space or is operating to supply hot water based on a sensing value of the first temperature sensor. The compressor may operate when the controller determines that the boiler is not operating to heat the indoor space and/or determines that the boiler is operating to supply hot water.

A relay includes a first relay unit and a second relay unit provided between an outdoor unit and an indoor unit to allow refrigerant to circulate between the first relay unit and the outdoor unit and between the second relay unit and the outdoor unit, and a heat medium circuit connecting the first relay unit and the second relay unit to the indoor unit to allow a heat medium to circulate through the heat medium circuit. The second relay unit is installed above or on a top of the first relay unit.

An air-conditioning apparatus includes outdoor units each including a compressor and outdoor heat exchanger, refrigerant flowing through the outdoor units; an indoor unit including an indoor heat exchanger, a heat medium flowing through the indoor unit; relay devices to which the outdoor units are connected, and to which the indoor unit is connected, each relay device includes a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium; and a controller. The controller controls action of the outdoor units, the indoor unit, and the relay devices. The controller determines necessity for a defrosting operation; responsive the defrosting operation being necessary, compares an indoor unit total load with an outdoor unit total capacity; and controls an operating frequency of the compressor of an outdoor unit other than the outdoor unit on which the defrosting operation is to be performed to increase the outdoor unit total capacity.

A refrigerant amount inference apparatus infers a refrigerant amount in an air conditioner in which a compressor, a heat source side heat exchanger, a supercooling heat exchanger, a pressure reducing valve, and a use side heat exchanger are connected to piping. The supercooling heat exchanger exchanges heat between refrigerant that passes through a valve provided in a bypass circuit and refrigerant in a mainstream circuit. The refrigerant amount inference apparatus includes an acquiring unit that acquires a state of refrigerant in first piping provided between the pressure reducing valve and the supercooling heat exchanger and an operation amount related to the state of the refrigerant in the first piping, and a training unit that performs training by associating the state of the refrigerant in the first piping and the operation amount related to the state of the refrigerant in the first piping with a refrigerant amount.