A control module for a refrigeration system includes a startup mode control module that receives an off time of a compressor and an ambient temperature, determines whether the off time and the ambient temperature indicate that the compressor is in a flooded condition, and selects, based on the determination, between a normal startup mode and a flooded startup mode. A compressor control module transitions from the flooded startup mode to the normal startup mode after a predetermined period associated with operating in the flooded startup mode and operates the compressor at a first speed in the normal startup mode and operates the compressor at a second speed less than the first speed in the flooded startup mode.

A HVAC system that includes a compressor comprising a suction port and a discharge port. Also included is a refrigerant circulating throughout the HVAC system and through the compressor. Further included is a pressure equalization valve fluidly coupling the discharge port of the compressor with the suction port of the compressor, the pressure equalization valve configured to open while the compressor is operating.

The present disclosure provides a refrigeration system and a control method of the refrigeration system. The refrigeration system includes a cooling circuit and a compressor, an evaporator assembly, and a condenser assembly sequentially arranged on the cooling circuit, and the refrigeration system further includes: a liquid pump cooling assembly, arranged on the cooling circuit and located between the condenser assembly and the evaporator assembly, the liquid pump cooling assembly includes a housing and a liquid pump arranged in the housing, the housing defines a cavity having a liquid reserving function, a refrigerant inlet, a first outlet connected to the cavity and a second outlet connected to the liquid pump, an outlet of the condenser assembly is in connected with the refrigerant inlet, and both the first and second outlets are connected with an inlet of the evaporator assembly; a control assembly, connected with the compressor and the liquid pump.

A method of operating a vapor compression system configured for environmentally conditioning a space comprising: providing a compressor of the vapor compression system with a variable speed drive, operating the compressor at a first speed in response to a start command, determining a demand speed of the compressor based at least in part on a user selected target value for an environmental condition within the space, determining a maximum allowable compressor speed of the compressor based at least in part on a condition of a parameter of the vapor compression system, reducing the speed of the compressor from the first speed to a second speed, maintaining the speed of the compressor below the first speed, and operating the compressor at the demand speed once a startup condition is satisfied.

A heat pump is provided with a compressor; an oil separator provided on a discharge path of the compressor; an accumulator connected to the compressor via a suction path; and a bypass circuit configured to supply a gas refrigerant separated by the oil separator. The bypass circuit is connected to the suction path.

A thermal management device includes two or more heat dissipation devices that dissipate heat into a heat medium, a heat medium-air heat exchanger that exchanges heat between air and the heat medium having its heat dissipated in the two or more heat dissipation devices, a flow-rate adjustment device that adjusts a flow rate of the heat medium flowing through the heat dissipation device, and a control unit. The control unit controls an operation of the flow-rate adjustment device to increase the flow rate of the heat medium flowing through the one heat dissipation device, if the control unit estimates an increase in the amount of heat dissipation into the heat medium at the one heat dissipation device of the two or more heat dissipation devices.

A refrigeration cycle apparatus comprises: a refrigerant cycle circuit, a condenser, a pressure-reducing device and an evaporator are sequentially connected by pipes; an injection circuit that branches off from the refrigerant cycle circuit between the condenser and the pressure-reducing device and is connected to the injection flow passage; a flow rate control device provided in the injection circuit or the injection flow passage; and a controller configured to control the flow rate control device. At a time of starting up the compressor, the controller, controls regardless of a temperature of refrigerant discharged from the compressor, the flow rate control device so as to supply refrigerant liquid to the compression chamber via the injection circuit and the injection flow passage until an operating capacity of the compressor reaches a preset operating capacity or until a preset time elapses after starting up the compressor.

An apparatus for staged startup of air-cooled low charged packaged ammonia refrigeration system includes motorized valves on condenser coil inlets, a main compressor discharge motorized valve, a bypass pressure regulator valve in the main compressor piping, and check valves on the condenser outlets. The condenser inlet motorized valves provide precise control of gas feed to the condensers, so pressure can build without collapsing oil pressure. The condenser outlet contains check valves to prevent liquid backflow during coil isolation. The compressor discharge line contains a motorized valve for regulating discharge pressure at start-up. The motorized valve in the compressor discharge piping includes a bypass with a pressure regulator for precise regulation at minimum discharge pressure. Once discharge pressure rises above the setpoint, the condenser inlet solenoid coils open one at a time. The discharge pressure regulating motorized valve simultaneously regulates the discharge pressure until the condenser maintains discharge pressure.

An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.

A system for starting a refrigeration system includes a liquid line regulating valve, a liquid line charging valve, a suction line expansion valve, a suction line charging valve, and a controller. The controller is configured to override normal operation of the refrigeration system and transmit a demand signal to enable partial system operation. The controller is configured to operate the liquid line regulating valve and the liquid line charging valve to charge a receiver tank, gradually increase the demand signal to a predetermined level of partial system operation, and release the liquid line charging valve to normal operation. The controller is configured to operate the suction line expansion valve and the suction line charging valve to charge a suction line, gradually increase the demand signal to full system operation, and release the liquid line regulating valve, the suction line expansion valve, and the suction line charging valve to normal operation.