Operating a vapor compression system including determining a total heat delivered by the vapor compression system, determining a total electrical energy consumed by the vapor compression system while delivering heat, maintaining a total electrical energy consumed by the vapor compression system during a defrosting cycle, determining a cumulative coefficient of performance of the vapor compression system based on the total heat delivered, the total electrical energy consumed by the vapor compression system while delivering heat, and the total electrical energy consumed by the vapor compression system during the defrosting cycle, and initiating a defrosting cycle based the cumulative coefficient of performance.

Embodiments of the present disclosure relate to a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system that includes a variable speed drive configured to provide power to a motor that drives a compressor of the HVAC&R system and a silicon carbide transistor of the variable speed drive, where the silicon carbide transistor is configured to adjust a voltage, or a frequency, or both of power flowing through the variable speed drive.

A refrigeration cycle device includes a first physical quantity detector that detects a first physical quantity having a correlation with a temperature of refrigerant flowing into an evaporator, a second physical quantity detector that detects a second physical quantity having a correlation with a temperature of ventilation air heat-exchanged in the evaporator to be blown into a space to be cooled, a defrosting operation determination portion that determines whether a defrosting operation of the evaporator is to be started based on whether a temperature difference between the temperature of the refrigerant specified by the first physical quantity and the temperature of the ventilation air specified by the second physical quantity is equal to or larger than a determination threshold value, and a defrosting operation execution portion that performs the defrosting operation of the evaporator when it is determined that defrosting operation of the evaporator is to be started.

Variable volume ratio compressors may be controlled using a switching parameter based on compressor speed and suction density to improve the matching of compressor volume ratio to desired discharge conditions. Delay periods may be implemented in the determination of when to change volume ratio to control the frequency of changes to the volume ratio. The switching parameter may be a product of the compressor speed and suction density. The volume ratio of the compressor may be controlled by switching valves directing pressure to a piston of a variable volume ratio system of the compressor.

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.

Provided is a control method on electronic expansion valve in air conditioner, which comprises: obtaining a real-time running frequency of compressor, a real-time exhaust temperature and a real-time outdoor environment temperature as the compressor running; if the air conditioner working in cooling mode, using a first set rule or a second set rule to obtain an integral coefficient in which the selection is based on the comparison of the real-time outdoor environment temperature and a first set outdoor environment temperature; if the air conditioner working in heating mode, using a first set rule or a third set rule to obtain an integral coefficient in which the selection is based on the comparison of the real-time outdoor environment temperature and a second set outdoor environment temperature; performing a PID control on the electronic expansion valve by using an error of the difference between real-time exhaust temperature and a set target exhaust temperature. The method realizes an accurate and stable control on opening amount of electronic expansion valve in air conditioner.

An air-conditioning system includes a heat-source device that includes a compressor and a heat-source-side heat exchanger, a relay device that includes a pump and an intermediate heat exchanger, and a plurality of indoor units that each include a load-side heat exchanger. The air-conditioning system includes a refrigerant circuit through which refrigerant circulates and a heat medium circuit through which a heat medium circulates. The air-conditioning system includes a flow rate detection unit configured to detect flow rate information associated with a flow rate of a heat medium that flows through each of the plurality of indoor units and a controller configured to control the compressor and the pump. The controller controls operation of at least either the compressor or the pump on the basis of the flow rate information detected by the flow rate detection unit.

A system and method are provided including a system controller for a refrigeration or HVAC system having a compressor rack with a compressor and a condensing unit with a condenser fan. The system controller monitors and controls operation of the refrigeration or HVAC system. A rack controller monitors and controls operation of the compressor rack and determines compressor rack power consumption data. A condensing unit controller monitors and controls operation of the condensing unit and determines condensing unit power consumption data. The system controller receives the compressor rack power consumption data and the condensing unit power consumption data, determines a total power consumption of the refrigeration or HVAC system, determines a predicted power consumption or a benchmark power consumption for the refrigeration system, compares the total power consumption with the predicted power consumption or the benchmark power consumption, and generates an alert based on the comparison.

A refrigeration device equipped with: a cascade cycle; a storage unit having a storage space for an object to be cooled by a second evaporator; an internal temperature sensor that detects the temperature of the storage space; a control unit that determines a second rotational speed of a second compressor on the basis of a target temperature for the storage space and the detection result from the internal temperature sensor, and that determines a first rotational speed for a first compressor having a prescribed correspondence relationship with the second rotational speed; and a first power supply unit and a second power supply unit that supply power respectively to the first compressor and the second compressor on the basis of the first rotational speed and the second rotational speed determined by the control unit.

A system includes a refrigerant compressor, an electric motor and configured to drive the refrigerant compressor, and a controller. The controller is configured to operate the compressor in a liquid clearing start mode where electrical current through the motor is prevented from exceeding a predetermined current limit for a period of time not to exceed a predetermined period of time, and is configured to operate the compressor in a run mode in response to determining the motor exceeds a predetermined speed threshold at or before expiration of the predetermined period of time, wherein the run mode does not prevent electrical current through the motor from exceeding said predetermined current limit.