An air conditioner includes: an outdoor unit; a plurality of indoor units respectively including indoor heat exchangers; expansion valves respectively provided to the plurality of indoor units, the expansion valves being configured to adjust flow rates of a refrigerant in the indoor heat exchangers; and a controller for executing a refrigerant amount balance control for adjusting opening degrees of the expansion valves so that operation state amounts, with which the indoor heat exchangers exert heat exchange amounts, of the plurality of indoor units become equal to each other.

An air conditioner unit includes a variable speed compressor for circulating refrigerant through refrigeration loop and a controller configured to initiate an operating cycle, start a compressor transition timer, and determine an unfiltered compressor speed. The unfiltered compressor speed is fixed based on the selected operating mode until the compressor transition timer reaches a predetermined transition delay time, after which the unfiltered compressor speed is determined using a closed loop feedback control algorithm. The controller is further configured to operating the variable speed compressor at a target compressor speed that is modified from the unfiltered compressor speed based on the identification of a speed modification condition, such as a dehumidification deficiency a speed restriction, or the identification of one or more resonance avoidance zones.

An air conditioner unit includes a variable speed compressor for circulating refrigerant through refrigeration loop and a controller configured to initiate an operating cycle, start a compressor transition timer, and determine an unfiltered compressor speed. The unfiltered compressor speed is fixed based on the selected operating mode until the compressor transition timer reaches a predetermined transition delay time, after which the unfiltered compressor speed is determined using a closed loop feedback control algorithm. The controller is further configured to operate the variable speed compressor at a target compressor speed that is modified from the unfiltered compressor speed based on the identification of a speed modification condition, such as a dehumidification deficiency, a speed restriction, or the identification of one or more resonance avoidance zones.

A method of performing a defrost operation in a heating, ventilation and air conditioning (HVAC) system having a first heat exchanger and a second heat exchanger, the method including determining that the defrost operation is needed; determining a capacity for the defrost operation in response to one or more prior defrost operations; beginning the defrost operation at the determined capacity; monitoring a defrost parameter; determining if the defrost parameter indicates a need for increased capacity; and increasing the capacity of the defrost operation when the defrost parameter indicates the need for increased capacity.

Disclosed are a compressor control method, control apparatus and control system. The method includes: receiving a cylinder switching instruction, and detecting operating parameters of a compressor; determining whether a cylinder switching operation is completed according to the operating parameters of the compressor; and after it is determined that the cylinder switching operation is completed, performing torque compensation.

A control method for a space conditioning system operable with a stages thermostat, the method including: powering a control module comprising including an output terminal, a first input terminal, a second input terminal, and control logic; detecting receipt of the first input signal at the first input terminal; responsive to detecting receipt of the first input signal, outputting a first value of the plurality of values, the first value corresponding to the first input signal; after outputting the first value, outputting one or more values of the plurality of values, the one or more values being larger than the first value; detecting receipt of the second input signal at the second input terminal; and responsive to detecting receipt of the second input signal, outputting a second value of the plurality of values, the second value corresponding to the second input signal.

Upon detection of a leakage of refrigerant, a refrigerant recovery operation is performed for operating a compressor in a state where an outdoor expansion valve is closed. The refrigerant suctioned from an indoor unit passes through an outdoor heat exchanger so as to be liquefied and accumulated in an outdoor unit. When a low-pressure detection value by a pressure sensor decreases below a reference value, a termination condition for the refrigerant recovery operation is satisfied, and the compressor is stopped. Furthermore, when an abnormality in the refrigerant recovery operation is detected based on a behavior of the low-pressure detection value obtained until the termination condition is satisfied, the compressor is stopped to thereby end the refrigerant recovery operation. Also, guidance information for notification about an abnormality is output to a user.

A heat cycle system and a control method. The heat cycle system includes: driving devices, one or a plurality of outdoor units, and a plurality of indoor units, which are connected by pipelines; a bypass pipeline for the plurality of indoor units, a bypass valve being disposed in the bypass pipeline; a pressure sensor that senses a pressure difference ΔP.sub.o across the plurality of outdoor units; and a controller that is preset with a pressure difference set value ΔP.sub.set, wherein the controller calculates a pressure offset parameter ΔP=ΔP.sub.o−ΔP.sub.set and adjusts an opening degree of the bypass valve based on the pressure offset parameter ΔP so that the pressure offset parameter ΔP approaches zero, and wherein the controller is preset with a first pressure offset threshold P.sub.1, and the controller is configured such that closed indoor units enter a bypass mode one by one when ΔP>P.sub.1, until ΔP≤P.sub.1.

An appliance includes an appliance housing, an interface adapted to receive power information, a plurality of sensors for sensing environmental conditions, a plurality of controls for controlling operations of the appliance, and an intelligent control. The intelligent control is disposed within the appliance housing and operatively connected to the interface and the plurality of sensors and adapted to dynamically select control values associated with the plurality of controls based on at least one of the power information, the environmental conditions, or a combination thereof to increase energy efficiency of the appliance.

A control device for a refrigerator system for cooling a load by using a plurality of refrigerators, said control device comprising a unit to control the number of operating units that changes the number of operating refrigerators according to the load rate, and a cold water temperature acquisition unit that acquires, via a temperature sensor, the temperature of cold water affected by the refrigerators. After a prescribed standby time from when the number of operating refrigerators was changed has elapsed, the unit to control the number of operating units changes the number of operating units and reduces the prescribed standby time when at least one of the cold-water temperature and the rate of change in the cold-water temperature satisfies a prescribed condition.