A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a first portion of a refrigeration system within a building; and an isolation module configured to selectively open and close an isolation valve of the refrigeration system and to, via the isolation valve, maintain the amount of refrigerant within the first portion within the building below a predetermined amount of the refrigerant.

A refrigeration cycle apparatus includes: a refrigeration cycle circuit in which a compressor, a condenser, a first expansion valve, and an evaporator are connected by refrigerant pipes; an injection pipe having a refrigerant inflow side end and a refrigerant outflow side end, the refrigerant inflow side being connected between the condenser and the first expansion valve, the refrigerant outflow side end being connected to a suction side of the compressor; a second expansion valve provided at the injection pipe; and a controller that controls a rotation speed of the compressor and an opening degree of the second expansion valve. In the case of reducing a heat-exchange capability of the evaporator when the rotation speed of the compressor is a specified rotation speed, the controller performs a low load operation during which refrigeration is caused to flow through the injection pipe.

An air-conditioning apparatus including heat source apparatuses each including a compressor and an accumulator includes: a refrigerant amount calculation unit that calculates an amount of the refrigerant accumulated in the accumulator in one of the heat source apparatuses that is to be controlled; a refrigerant differential amount calculation unit configured to calculate, when the number of the heat source apparatuses is two, a differential amount between the calculated amount and an amount of the refrigerant in the accumulator in the other heat source apparatus, and calculate, when the number of the heat source apparatuses is three or more, a differential amount between the calculated amount of the refrigerant and an average amount of amounts of the refrigerant accumulated in the accumulators in the heat source apparatuses; and a liquid equalization control unit that controls the heat source apparatus to be controlled, based on the calculated differential amount.

A performance degradation diagnosis system includes a determining unit, and control unit. A refrigeration cycle apparatus includes a refrigerant circuit having a compressor, heat-source-side heat exchanger, and use-side heat exchanger. The determining unit determines, based on an index indicating an operation state of the refrigeration cycle apparatus, performance degradation of the refrigeration cycle apparatus with respect to each of a plurality of performance degradation factors. In a case in which the determining unit determines performance degradation, the control unit grasps an operation condition of the refrigeration cycle apparatus which is operating. In a case in which the operation condition of the refrigeration cycle apparatus is not suitable to determine performance degradation with respect to a performance degradation factor of a determination target, the control unit controls the operation condition of the refrigeration cycle apparatus so that the operation condition of the refrigeration cycle apparatus becomes an appropriate operation condition.

Disclosed is a method of controlling a refrigerator, including detecting outside temperature through an outside temperature sensor configured to detect ambient temperature of the refrigerator, performing a winter operation when the outside temperature detected by the outside temperature sensor is equal to or less than a set temperature, and determining a normal operation to be performed when the temperature detected by the outside temperature sensor is higher than the set temperature, wherein, during the winter operation, the compressor is operated with higher cooling power than in the normal operation.

A system and a method for controlling temperature inside electrical and electronics systems. The method includes sensing temperature of an inverter section by a temperature sensor, the inverter section including one or more electronic components. The method also includes determining, by a microcontroller, a temperature zone based on the sensed temperature and transmit a command to an inverter based on the temperature zone. The method further includes controlling speed of a compressor by an inverter based on the command.

A variable refrigerant flow (VRF) air conditioning system, a control method thereof, and a computer-readable storage medium are provided. When the VRF air conditioning system is cooling, indoor units in an operating state are obtained. Indoor units with humidity demand and indoor units without humidity demand in the operating state are obtained. A ratio of humidity demand is determined according to an output nominal value of each indoor unit in the operating state. The ratio can include a ratio of a total output nominal value of indoor units with humidity demand to a total output nominal value of indoor units without humidity demand When the ratio is greater than a preset ratio, a rotation speed of an outdoor fan can be adjusted according to an outdoor environment temperature.

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 system is provided. The system has a high-pressure pipe, a low-pressure pipe, an indoor heat exchanger, an outdoor heat exchanger, a leak-free thermal expansion valve and a variable capacity compressor. The variable capacity compressor has a shell, a first cylinder and a second cylinder. The shell has a suction port and an exhaust port. The first cylinder has a first suction hole connected to the suction port and a first exhaust hole connected to the exhaust port. The second cylinder has a second suction hole connected to the suction port, a second exhaust hole connected to the exhaust port, and a pressure relief hole connected to the high-pressure pipe and the low-pressure pipe in an on-off manner. Before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected and also disconnected after the first preset duration.

A method for controlling suction pressure in a vapour compression system including one or more cooling entities is disclosed. For each cooling entity, a maximum required suction pressure and/or a required change in suction pressure for maintaining a target temperature in the refrigerated volume is obtained. A most loaded cooling entity among the one or more cooling entities is identified, based on the maximum required suction pressures and/or the required changes in suction pressure. The suction pressure of the vapour compression system is controlled in accordance with the maximum required suction pressure and/or required change in suction pressure for the identified most loaded cooling entity.