A dynamic receiver is included in parallel to an expander of a heating, ventilation, air conditioning, and refrigeration (HVACR) system. The dynamic receiver allows control of the refrigerant charge of the HVACR system to respond to different operating conditions. The dynamic receiver can be filled or emptied in response to the subcooling observed in the HVACR system compared to desired subcooling for various operating modes. The HVACR system can include a line directly conveying working fluid from compressor discharge to the dynamic receiver to allow emptying of the dynamic receiver to be assisted by injection of the compressor discharge.

A dynamic receiver is included in parallel to an expander of a heating, ventilation, air conditioning, and refrigeration (HVACR) system. The dynamic receiver allows control of the refrigerant charge of the HVACR system to respond to different operating conditions. The dynamic receiver can be filled or emptied in response to the subcooling observed in the HVACR system compared to desired subcooling for various operating modes. The flow through an expander of the HVACR system can be controlled to account for the mass flow rate through an outlet valve of the dynamic receiver when the dynamic receiver is emptied, preventing or reducing instability or effects on system parameters such as the suction superheat.

The present disclosure provides a multi-air conditioner for heating/cooling operation including: at least one of indoor units for heating/cooling operation including an indoor heat exchanger respectively; and an outdoor unit for heating/cooling operation including a compressor, an outdoor heat exchanger, and a switching unit configured to be disposed in a discharge side of the compressor to switch a flow of refrigerant, wherein the outdoor unit for heating/cooling operation includes a receiver which selectively stores refrigerant or oil according to a cooling or heating operation mode and provides the stored refrigerant or oil to the compressor. Accordingly, in the accumulator of the multi-air conditioner for heating/cooling operation using the receiver, the receiver that is not used in the heating mode can be converted and used for oil storage, thereby preventing oil burnout without adding a structure.

A dynamic refrigeration system may automatically, at pre-determined time periods on-the-fly, adjust a refrigerant system's refrigerant pressures to predetermined optimal efficiency pressures as the internal and external heat loads change over a range. This may result in the refrigerant system pressures closely operating within a range of predetermined optimal efficiency pressures. This system may automatically instantaneously fine tune and balance on all air conditioning, heat pump, and refrigeration systems as the internal and external heat loads are continuously changing dynamically. The system may include a small liquid refrigerant pump and refrigerant storage tank, one or more wired or wireless pressure transducers and temperature sensors, and a “brain” to make decisions to keep the system instantaneously set at factory specs all the time. The system may include a wireless communication means so it can instantaneously report its operating condition, loads, and cost of operating.

A vapor compression refrigeration system has a main refrigerant circuit having a primary compressor group, a gas cooler or condenser, an expansion device, a liquid receiver, and at least one evaporator. An emergency circulation duct fluidically connects the liquid receiver to the main circuit to allow a flow of refrigerant from the liquid receiver to the gas cooler. An emergency compressor group in the emergency circulation duct is activatable when pressure inside the liquid receiver or in the duct upstream of the emergency compressor group meets or exceeds a predefined emergency pressure threshold. An uninterruptible power supply powers the emergency compressor group and expansion device during a shutdown of the refrigeration system. When pressure inside the liquid receiver or in the duct upstream of the emergency compressor group equals or exceeds the predefined emergency pressure threshold, an emergency circulation of refrigerant fluid is activated through the emergency circulation duct.

A dynamic refrigeration system may automatically, at pre-determined time periods on-the-fly, adjust a refrigerant system's refrigerant pressures to predetermined optimal efficiency pressures as the internal and external heat loads change over a range. This may result in the refrigerant system pressures closely operating within a range of predetermined optimal efficiency pressures. This system may automatically instantaneously fine tune and balance on all air conditioning, heat pump, and refrigeration systems as the internal and external heat loads are continuously changing dynamically. The system may include a small liquid refrigerant pump and refrigerant storage tank, one or more wired or wireless pressure transducers and temperature sensors, and a “brain” to make decisions to keep the system instantaneously set at factory specs all the time. The system may include a wireless communication means so it can instantaneously report its operating condition, loads, and cost of operating.

A refrigeration system includes a main refrigeration circuit for holding refrigerant fluid, the main refrigeration circuit including: a compression device 12, a heat rejecting heat exchanger 14, an expansion device 18 and a heat absorbing heat exchanger 16. In addition, the refrigeration system includes a buffer tank 20 attached to the main refrigeration circuit, with valves 22, 24 for controlling flow of refrigerant fluid between the main refrigeration circuit and the buffer tank 20. The refrigeration system is arranged such that the valves 22, 24 are controlled to transfer refrigerant fluid between the main refrigeration circuit and the buffer tank 20 based on a measure of sub-cooling in the main refrigeration circuit.

An HVAC system includes an evaporator coil and a compressor fluidly coupled to the evaporator coil. A condenser coil is fluidly coupled to the compressor. The condenser coil includes at least one condenser circuit fluidly coupled between a discharge line and an exit manifold. A sub-cool circuit is fluidly coupled between the exit manifold and a liquid line. A first temperature sensor is disposed at an entrance to the sub-cool circuit. A second temperature sensor is disposed at an exit to the sub-cool circuit. An HVAC controller is operatively coupled to the first temperature sensor and the second temperature sensor. The HVAC controller is configured to determine a temperature difference across the sub-cool circuit.

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.

Provided is a multi-type air conditioner, including: an outdoor unit having a liquid pipe through which a liquid refrigerant flows, and a gas pipe through which a gas refrigerant flows; a plurality of indoor units comprising a first indoor unit and a second indoor unit each connected to the liquid pipe and the gas pipe to circulate a refrigerant; a gas pipe connecting tube connecting the gas pipe and the plurality of indoor units so that a gas refrigerant flows therethrough; and a liquid pipe connecting tube connecting the liquid pipe and the plurality of indoor units so that a liquid refrigerant flows therethrough. The first indoor unit may include: a first indoor heat exchanger comprising a first heat exchanger configured to perform heat exchange between indoor air and a refrigerant, and a second heat exchanger configured to perform heat exchange between indoor air and a refrigerant and arranged in a stacked fashion with the first heat exchanger; a first indoor fan configured to blow air to the first heat exchanger and the second heat exchanger; a first liquid branch pipe connecting the liquid pipe connecting tube and the first heat exchanger so that a refrigerant flows therethrough; a first gas branch pipe connecting the gas pipe connecting tube and the second heat exchanger so that a refrigerant flows therethrough; a first heat exchanger connecting pipe connected to the first heat exchanger so that a refrigerant flows therethrough; a second heat exchanger connecting pipe connected to the second heat exchanger so that a refrigerant flows therethrough; a return pipe having one side connected to the first gas branch pipe and the other side connected to the first heat exchanger connecting pipe and the second heat exchanger connecting pipe; a first indoor expansion valve disposed at the second heat exchanger connecting pipe, wherein an opening amount of the first indoor expansion valve is adjusted in response to an input signal from a controller to selectively expand a flowing refrigerant; and a first expansion valve disposed in the return pipe, wherein an opening amount of the first expansion valve is adjusted in response to an input signal from the controller to selectively expand a flowing refrigerant.

Since the multi-type air conditioner according to the present disclosure can operate the first heat exchanger as a condenser and the second heat exchanger as an evaporator among the indoor heat exchangers, it is possible to constantly operate the dehumidifying mode while maintaining a room temperature within a predetermined range.