In a case of a heating operation in which the use side heat exchanger functions as a condenser when an outside temperature is a predetermined low temperature, a low-outside-temperature heating operation start-up mode in which, while a refrigerant discharged from the compressor is caused to flow into the use side heat exchanger, a refrigerant is supplied to the injection port of the compressor via the injection pipe and part of the refrigerant that has transferred heat in the heat source side heat exchanger is supplied to the compressor, is followed by a low-outside-temperature heating operation mode in which the refrigerant discharged from the compressor is supplied to the injection port of the compressor via the injection pipe while the refrigerant being caused to flow into the use side heat exchanger.

Generally, a variable fan speed control in an HVAC system is described. Such methods and systems to control fan speed can in turn improve efficiency of the HVAC system by minimizing power consumption, for example of the compressor. The control scheme is based on various operating conditions of compressor load and ambient air temperature, which are used to determine an optimum fan speed.

An air conditioner is provided. The air conditioner may include a compressor, an outdoor heat-exchanger, an indoor heat-exchanger, a converter valve, an accumulator, an accumulator jacket, and a supercooling heat-exchange hub. The accumulator jacket may be disposed on a surface of the accumulator and contain a refrigerating fluid flowing therein. The refrigerating fluid may exchange heat with the accumulator to be cooled. The supercooling heat-exchange hub may be connected to the accumulator jacket to store the cooled refrigerating fluid and overcool the refrigerant flowing between the outdoor heat-exchanger and the indoor heat-exchanger.

An air conditioner is provided. The air conditioner may include a compressor, an outdoor heat-exchanger, an indoor heat-exchanger, a converter valve, an accumulator, an accumulator jacket, and a supercooling heat-exchange hub. The accumulator jacket may be disposed on a surface of the accumulator and contain a refrigerating fluid flowing therein. The refrigerating fluid may exchange heat with the accumulator to be cooled. The supercooling heat-exchange hub may be connected to the accumulator jacket to store the cooled refrigerating fluid and overcool the refrigerant flowing between the outdoor heat-exchanger and the indoor heat-exchanger.

The present invention is characterized in that: a flow diverter provided in an air conditioner has a flow diverter main body having an internal space, and a first connection portion to which a pipe is connected; the first connection portion has an inner peripheral surface that defines a hole through which the pipe is inserted; the inner peripheral surface has, in the direction of a central axis, a brazing portion which is provided at a location containing an end on the side where the pipe is inserted, and forms a gap filled with solder for brazing between the inner peripheral surface and an outer peripheral surface of the pipe, and a restricting portion located closer to the flow diverter main body than to the brazing portion; and the inner diameter of the restricting portion is smaller than the inner diameter of the brazing portion.

The present invention is characterized in that: a flow diverter provided in an air conditioner has a flow diverter main body having an internal space, and a first connection portion to which a pipe is connected; the first connection portion has an inner peripheral surface that defines a hole through which the pipe is inserted; the inner peripheral surface has, in the direction of a central axis, a brazing portion which is provided at a location containing an end on the side where the pipe is inserted, and forms a gap filled with solder for brazing between the inner peripheral surface and an outer peripheral surface of the pipe, and a restricting portion located closer to the flow diverter main body than to the brazing portion; and the inner diameter of the restricting portion is smaller than the inner diameter of the brazing portion.

A method for controlling a variable capacity ejector unit (7) arranged in a refrigeration system (1) is disclosed. An ejector control signal for the ejector unit (7) is generated, based on an obtained temperature and an obtained pressure of refrigerant leaving a heat rejecting heat exchanger (3), or on the basis of a high pressure valve control signal for controlling an opening degree of a high pressure valve (6) arranged fluidly in parallel with the ejector unit (7). The ejector control signal indicates whether the capacity of the ejector unit (7) should be increased, decreased or maintained. The capacity of the ejector unit (7) is controlled in accordance with the generated ejector control signal. The power consumption of the refrigeration system (1) is reduced, while the pressure of the refrigerant leaving the heat rejecting heat exchanger (3) is maintained at an acceptable level.

A method for controlling a variable capacity ejector unit (7) arranged in a refrigeration system (1) is disclosed. An ejector control signal for the ejector unit (7) is generated, based on an obtained temperature and an obtained pressure of refrigerant leaving a heat rejecting heat exchanger (3), or on the basis of a high pressure valve control signal for controlling an opening degree of a high pressure valve (6) arranged fluidly in parallel with the ejector unit (7). The ejector control signal indicates whether the capacity of the ejector unit (7) should be increased, decreased or maintained. The capacity of the ejector unit (7) is controlled in accordance with the generated ejector control signal. The power consumption of the refrigeration system (1) is reduced, while the pressure of the refrigerant leaving the heat rejecting heat exchanger (3) is maintained at an acceptable level.

A heating, ventilation, and air-conditioning (HVAC) conduit includes a first HVAC line at least partially nested within a second HVAC line having a configuration defining a U- or C-shaped receiver in cross-section. The first HVAC line is fabricated of a first material and the second HVAC line is fabricated of a second material that is different from the first material.

A system has a compressor, a heat rejection heat exchanger, first and second ejectors, first and second heat absorption heat exchangers, and a separator. The ejectors each have a primary inlet coupled to the heat rejection exchanger to receive refrigerant. A second heat absorption heat exchanger is coupled to the outlet of the second ejector to receive refrigerant. The separator has an inlet coupled to the outlet of the first ejector to receive refrigerant from the first ejector. The separator has a gas outlet coupled to the secondary inlet of the second ejector to deliver refrigerant to the second ejector. The separator has a liquid outlet coupled to the secondary inlet of the first ejector via the first heat absorption heat exchanger to deliver refrigerant to the first ejector.