An air-conditioning apparatus includes: a plurality of outdoor units each including a compressor and an outdoor heat exchanger, refrigerant flowing through the plurality of outdoor units; an indoor unit including an indoor heat exchanger, a heat medium flowing through the indoor unit; a plurality of relay devices to which the plurality of outdoor units are connected independently, and to which the indoor unit is connected, each of the plurality of relay devices including a heat medium heat exchanger configured to exchange heat between the refrigerant and the heat medium; and a controller configured to control action of the plurality of outdoor units, the indoor unit, and the plurality of relay devices, wherein the controller includes a defrost determination unit configured to determine necessity for a defrosting operation, a load determination unit configured to compare, in a case where the defrosting operation is necessary, an indoor unit total load with an outdoor unit total capacity, and an equipment control unit configured to control an operating frequency of the compressor of an outdoor unit other than the outdoor unit on which the defrosting operation is to be performed such that the outdoor unit total capacity is increased in a case where the indoor unit total load is greater than the outdoor unit total capacity.

A dehumidifier for operation within the 5° C. to 20° C. temperature range and 50 to 100 percent relative humidity range of air includes an evaporator, a condenser, a fan that draws humid air through the evaporator and condenser, and a compressor for pumping refrigerant fluid through both the evaporator and condenser. The evaporation temperature is maintained in the evaporator at least at −4° C., resulting in a temperature within the evaporator and at the outlet thereof being greater than 0° C., thereby preventing the formation of ice in the evaporator and allowing the operation of the evaporator to its full power all the time.

A cooling system includes an ingress port to receive refrigerant in a vapor form from an evaporator, an egress port to return refrigerant in a liquid form back to the evaporator, a condenser coupled to the ingress port and the egress port, and a compressor coupled to the ingress port and the condenser. When the cooling system operates in a first mode, the condenser is configured to receive and condense the refrigerant from the vapor form into the liquid form and to return the refrigerant in the liquid form to the regress port. When the cooling system operates in a second mode, the compressor is configured to compress the refrigerant in the vapor form and to supply the compressed refrigerant to the condenser to be condensed therein.

A method and a device for controlling a capacity change of a compressor, and a smart home appliance. The method includes: determining whether a capacity of the compressor is required to be changed; if yes, determining an intermediate frequency; changing the capacity of the compressor while maintaining the operating frequency of the compressor at the intermediate frequency; and the maintaining the operating frequency of the compressor at the intermediate frequency reduces a sudden change in output of the compressor after the changing the capacity.

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 system and method for a compressor includes a compressor connected to a condenser, a discharge line temperature sensor that outputs a discharge line temperature signal corresponding to a discharge line temperature of refrigerant leaving the compressor, and a control module connected to the discharge line temperature sensor. The control module determines a saturated condenser temperature, calculates a discharge superheat temperature based on the saturated condenser temperature and the discharge line temperature, and monitors a flood back condition of the compressor by comparing the discharge superheat temperature with a predetermined threshold. The control module increases a speed of the compressor when the discharge superheat temperature is less than or equal to the predetermined threshold.

Systems and methods for providing an improved strategy for controlling a variable speed water pump in a vehicle. In some embodiments, more than one water pump speed function is calculated based on values obtained from vehicle sensors, and a controller chooses among the water pump speed function results to set a water pump speed. In some embodiments, the water pump speed is increased when driveline torque is greater than a threshold amount for an amount of time that varies based on the driveline torque. In some embodiments, ambient temperature is considered while determining whether the water pump should provide full coolant flow to an auxiliary coolant loop of a trailer.

An HVAC system includes an evaporator. The evaporator includes a sensor configured to measure a property value (i.e., a saturated suction temperature or a saturated suction pressure) associated with saturated refrigerant flowing through the evaporator. The system includes a variable-speed compressor configured to receive the refrigerant and compress the received refrigerant. The system includes a controller communicatively coupled to the sensor and the variable-speed compressor. The controller monitors the property value measured by the sensor and detects a system fault, based on the monitored property value. In response to detecting the system fault, the controller operates the compressor in a freeze-prevention mode, which is configured to maintain the property value above a setpoint value by adjusting a speed of the variable-speed compressor. This prevents or delays freezing of the evaporator during operation of the system during the detected system fault.

A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a compressor with a gas bearing supplied with compressed gas and a controller. The controller is configured to determine an inlet pressure and outlet pressure of the gas bearing, determine a maximum speed limit based on the inlet pressure and the outlet pressure, and prevent the compressor from operating at a speed that is greater than the maximum speed limit. A method of controlling a compressor includes calculating a maximum speed limit based on an inlet pressure and an outlet pressure of the gas bearing. The method also includes in response to determining that a speed setting is greater than the maximum speed limit, adjusting operation of the compressor such that a speed of the compressor is at or below the maximum speed limit.

Systems and methods for a vapor compression system including primary actuators, secondary actuators, primary sensors that provide a primary set of system outputs, and secondary sensors that provide a secondary set of system outputs. A primary controller receives the primary set of system outputs, and produces a primary set of control inputs for the primary actuators, to regulate one or more zone temperatures to set-points and to regulate one or more critical process variables to set-points. A secondary controller receives the secondary set of system outputs, and produces a secondary set of control inputs, to minimize an overall system power consumption. The secondary inputs may include set-points to the primary controller. The primary outputs may include estimates of critical process variables that are used as inputs to the secondary controller.