A metering device may automatically control fluid flow through a valve. A control system may alter the automatic control of a metering device. In some implementations, a predetermined event may occur to alter the automatic control of the metering device.

A metering device may automatically control fluid flow through a valve. A control system may alter the automatic control of a metering device. In some implementations, a predetermined event may occur to alter the automatic control of the metering device.

A refrigeration system having a refrigerant circuit including a condenser, a flow control device, an evaporator, and a compressor connected in series. The compressor is configured to circulate a cooling fluid through the refrigerant circuit. The refrigerant circuit has an inlet line fluidly connecting the condenser to the evaporator and a suction line fluidly connecting the evaporator to the compressor. A heater is positioned to heat the cooling fluid during a defrost mode, and a pressure control is coupled to the refrigerant circuit downstream of the evaporator. In the defrost mode, the pressure control apparatus is configured to increase system pressure during the defrost mode to maintain flow of refrigerant into the evaporator and to control flow of cooling fluid to the compressor.

A method of operating a refrigeration system is provided. The method includes activating an evaporator heater (306), monitoring a pressure differential within the refrigeration system (308), when the pressure differential reaches a predetermined value (310), deactivating the evaporator heater (312), and activating one or more evaporator fans (314), after deactivating the evaporator heater, to cause a thermostatic expansion valve to open.

A method of operating a refrigeration system is provided. The method includes activating an evaporator heater, monitoring a pressure differential within the refrigeration system, when the pressure differential reaches a predetermined value, deactivating the evaporator heater, and activating one or more evaporator fans, after deactivating the evaporator heater, to cause a thermostatic expansion valve to open.

An air conditioning system and a startup control method. The air conditioning system includes: a compressor, a condenser, a thermal expansion valve and an evaporator connected via a pipeline; and a thermal temperature sensing bulb disposed on an outlet pipeline of the evaporator and associated with the thermal expansion valve; the air conditioning system further includes a thermal power source which is thermally coupled to the thermal temperature sensing bulb and controlledly cools or heats the thermal temperature sensing bulb. The thermal temperature sensing bulb is cooled or heated, as needed, by a thermal power source thermally coupled to the thermal temperature sensing bulb, thereby enabling the thermal expansion valve associated with the thermal temperature sensing bulb to be opened and closed more smoothly.

A metering device may automatically control fluid flow through a valve. A control system may alter the automatic control of a metering device. In some implementations, a predetermined event may occur to alter the automatic control of the metering device.

A metering device may automatically control fluid flow through a valve. A control system may alter the automatic control of a metering device. In some implementations, a predetermined event may occur to alter the automatic control of the metering device.

A method of operating a refrigeration system is provided. The method includes activating an evaporator heater, monitoring a pressure differential within the refrigeration system, when the pressure differential reaches a predetermined value, deactivating the evaporator heater, and activating one or more evaporator fans, after deactivating the evaporator heater, to cause a thermostatic expansion valve to open.

Air conditioning systems and processes may monitor properties of the system and/or properties related to the system. The air conditioning system may allow operation based on user requests and/or allow stress operation(s) based on monitored properties.