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.

A method for estimating refrigerant charge for an HVACR system is provided. The method includes obtaining one or more system parameters during operation. The one or more system parameters include at least one of compressor suction superheat, system mass flow, expansion device mass flow or opening degree, compressor suction saturated temperature, and compressor discharge saturated temperature. The method also includes conducting a regression analysis on the one or more system parameters to determine one or more predictive parameters for estimating the refrigerant charge. The method further includes determining a predictive model based on regression analysis. The predictive model establishes a relationship between the refrigerant charge and the one or more predictive parameters. Also the method includes estimating the refrigerant charge based on the predictive model.

A diagnostic system for a refrigeration system including a condenser is provided. The diagnostic system may include a controller determining a subcooling temperature of the refrigeration system, an approach temperature of the condenser, and a condenser temperature difference of the condenser. The controller may determine at least one of a fault condition of the refrigeration system and a charge of the refrigeration system based on the subcooling temperature, the approach temperature, and the condenser temperature difference.

A microchannel heat exchanger has an upper portion connected in fluid communication with a header, a lower portion connected in fluid communication with the header at a location that is vertically lower on the header than the upper portion, and a sight glass on the header. The sight glass can be horizontally aligned with a top of the second portion. The sight glass can be served as a visual aid when charging the microchannel heat exchanger with a refrigerant at a predetermined level. When an indicator indicates that refrigerant is mixed vapor and liquid, refrigerant can be added into the microchannel heat exchanger. When the indicator indicates that the refrigerant is liquid, the charging process can be stopped.

A method for charging a field refrigeration system including an evaporator, a condenser, a compressor, and an expansion device includes calculating a target superheat as a function of one or more of a measured field outdoor dry bulb temperature, and a measured field indoor wet bulb temperature. A charge adjustment percentage can be calculated as a function of the target superheat. A refrigerant adjustment weight can be determined based on the charge adjustment percentage. A field refrigeration system charge can be adjusted by the refrigerant adjustment weight.

A method for charging a field refrigeration system including an evaporator, a condenser, a compressor, and an expansion device includes calculating a field subcooling of the field refrigeration system as a function of a measured field liquid line pressure and a measured field liquid line temperature. A charge adjustment percentage can be calculated as a function of the field subcooling, a measured field indoor wet bulb temperature, and a measured field outdoor dry bulb temperature. A refrigerant adjustment weight can be determined based on the charge adjustment percentage. A field refrigeration system charge can be adjusted by the refrigerant adjustment weight.

An air conditioner and a control method of an air conditioner are provided. The air conditioner includes an outdoor unit, an indoor unit, a refrigerant circulation loop, and a controller. The controller is configured to determine whether the air conditioner is operating in a cooling mode; obtain a first target supercooling degree in a first standard condition if it determined that the air conditioner is operating stably in the cooling mode; convert a supercooling degree in a current condition into a supercooling degree in the first standard condition; obtain a first refrigerant amount difference according to the first target supercooling degree, the supercooling degree in the first standard condition, an outdoor unit internal volume in the first standard condition, and an outdoor unit internal volume in the current condition; and determine a refrigerant amount of the air conditioner according to the first refrigerant amount difference.

A refrigerator includes: a compressor; a condenser; a hot pipe; at least one capillary tube; at least one evaporator; a valve device including: an input port connected to the condenser; a first port connected to one end of the hot pipe; a second port connected to an other end; and at least one output port connected to the at least one capillary tube; and a controller configured to: control the valve device to operate in the first mode by connecting one of the first port and the second port to the input port and connecting an other one to the output port; control the valve device to operate in the second mode, by closing one of the first port and the second port and connecting an other one to the output port; and control the valve device to operate in the third mode, by closing all the first port and the second port.

A refrigeration apparatus includes: a refrigerant circuit through which refrigerant circulates; a controller to execute a plurality of refrigerant shortage sensing functions of sensing a shortage of an amount of the refrigerant; and an input device through which an operation mode to be set is input into the controller. The operation mode includes: a first mode in which energy-saving performance is emphasized; and a second mode in which the refrigeration apparatus is permitted to operate in a range in which reliability is ensured. In accordance with the operation mode set through the input device, the controller determines which one of sensing results obtained by the refrigerant shortage sensing functions is enabled and which one of sensing results obtained by the refrigerant shortage sensing functions is disabled. When a sensing result determined to be enabled shows a refrigerant shortage, the controller gives a notification about the refrigerant shortage.

An automated refrigerant recharging system determines whether a cooling load parameter of a direct expansion (DX) cooling system that cools information technology (IT) modules of an information handling system (IHS) has reached a defined recharging threshold that results in a response of the pressure value for measurement by the pressure transducer. In response to the cooling load parameter being equal to or greater than the defined recharging threshold, a controller determines whether a pressure value of the refrigerant of the DX cooling system is less than a defined target pressure value corresponding to the defined recharging threshold. In response to determining that the pressure value of the refrigerant of the DX cooling system is less than the defined target pressure value, the controller autonomously opens a control valve to transfer refrigerant to the DX cooling system.