An air conditioning system capable of reducing noise incidental to gas-liquid two-phase transfer is provided. The air conditioning system (100) performs a refrigeration cycle in a refrigerant circuit (RC) including an outdoor unit (10), a plurality of indoor units (40), and a liquid-side connection pipe (LC) connecting the outdoor unit (10) and the indoor units (40). The air conditioning system (100) includes a second outdoor control valve (17, electric valve) decompressing the refrigerant flowing in the refrigerant circuit (RC) in accordance with an opening degree, an operating-capacity variation detection portion (74, detection portion) detecting change of the number of operating units in accordance with device information, and a device control portion (75, control portion) controlling a state of the second outdoor control valve (17). The device control portion (75) executes first control (feed-forward control) when the change of the number of operating units is detected by the operating-capacity variation detection portion (74), and adjusts the opening degree of the second outdoor control valve (17) to suppress a rise of pressure of the refrigerant flowing into the operating unit.

A switching mechanism (TV1, TV2, TV3, TV4, FV) includes an electric motor (74), a flow path switching portion (71) to be driven by the electric motor (74), a first port (P1) connected to a high-pressure flow path (7, 24, 28b, 31, 32) of a refrigerant circuit (6), a second port (P2) connected to a low-pressure flow path (8, 25, 28a, 33, 34) of the refrigerant circuit (6), and a third port (P3) connected to a predetermined flow path of the refrigerant circuit (6). The switching mechanism (TV1, TV2, TV3, TV4, FV) is switched between a first state in which the first port (P1) communicates with the third port (P3) and a second state in which the second port (P2) communicates with the third port (P3) in such a manner that the electric motor (74) drives the flow path switching portion (71).

There is provided an air conditioner capable of displaying sufficient cooling ability in each indoor unit by allowing a sufficient amount of refrigerant to flow into indoor units where cooling ability cannot be displayed. By executing refrigerant amount balance control, since degrees of opening of indoor expansion valves are narrowed in indoor units whose refrigerant superheating degrees are smaller than an average refrigerant superheating degree, amounts of refrigerant flowing into the indoor expansion valves are decreased. In the indoor unit where the refrigerant superheating degree is higher than the average refrigerant superheating degree, since refrigerant pressure on a downstream side of the indoor expansion valve is also decreased due to the degrees of opening of the indoor expansion valves being narrowed, the difference in pressure between the upstream side and the downstream side of the indoor expansion valve increases and an amount of refrigerant flowing into the indoor unit is increased.

An air conditioning apparatus may include an outdoor unit through which a first fluid, such as refrigerant circulates, an indoor unit through which a second fluid, such as water circulates, a heat exchange device which is configured to connect the outdoor unit to the indoor unit and in which the first fluid and the second fluid are heat-exchanged with each other, a first inner tube which is configured to connect the outdoor unit to the heat exchange device and through which the first fluid at high-pressure flows, a second inner tube which is configured to connect the outdoor unit to the heat exchange device and through which the first fluid at low-pressure flows, and a third inner tube which is configured to connect the outdoor unit to the heat exchange device and through which the first fluid in liquid form flows. The heat exchange device may include a bypass tube configured to bypass the second inner tube and a flow control valve provided in the bypass tube.

A heat pump unit and methods for operating the heat pump unit are provided. The heat pump unit includes a compressor (101), a throttling device (107), a first heat exchanger (104), a second heat exchanger (102), a third heat exchanger (103) and a mid-pressure tank (110). The heat pump unit operates in multiple run modes and switches between the run modes without shutdown. The first heat exchanger or the second heat exchanger is capable of acting as a condenser in the multiple run modes. When switching from a pre-switching run mode to a post-switching run mode, a control device determines whether to perform a pressure release operation to the first heat exchanger or the second heat exchanger.

Systems and methods are presented for improving stabilization of a heating, ventilating, and air conditioning (HVAC) system. More specifically, the systems and methods include a heat-flow modulator for regulating an exchange of thermal energy between a flow of refrigerant and a sensory bulb. The exchange of thermal energy allows an expansion valve to respond to a refrigerant temperature using an actuator, which is coupled to the sensory bulb. The heat-flow modulator is formed of a body that includes a first contact surface and a second contact surface. The first contact surface is thermally-coupled to a suction line of the HVAC system, which conveys the flow of refrigerant. The second contact surface is thermally-coupled to the sensory bulb. In one instance the heat-flow modulator has variable volume depending on how installed. Other systems and methods are presented. Variable heat-flow modulators are also presented.

The air-conditioning apparatus includes the plurality of heat source apparatuses; a plurality of indoor units each including an indoor heat exchanger and each configured to perform one of cooling and heating operations; a relay device connected to the heat source apparatuses by a high pressure pipe and a low pressure pipe and configured to distribute refrigerant flowing therein from the heat source apparatuses to the plurality of indoor units; and a controller configured to control operations of the heat source apparatuses. The relay device includes a relay device temperature detecting unit configured to detect a temperature of the refrigerant flowing through the bypass pipe. During the heating main operation, the controller changes an opening degree of each of the outdoor side expansion devices based on the temperature detected by the relay device temperature detecting unit.

An air conditioning system capable of reducing noise incidental to gas-liquid two-phase transfer is provided. The air conditioning system (100) performs a refrigeration cycle in a refrigerant circuit (RC) including an outdoor unit (10), a plurality of indoor units (40), and a liquid-side connection pipe (LC) connecting the outdoor unit (10) and the indoor units (40). The air conditioning system (100) includes a second outdoor control valve (17, electric valve) decompressing the refrigerant flowing in the refrigerant circuit (RC) in accordance with an opening degree, an operating-capacity variation detection portion (74, detection portion) detecting change of the number of operating units in accordance with device information, and a device control portion (75, control portion) controlling a state of the second outdoor control valve (17). The device control portion (75) executes first control (feed-forward control) when the change of the number of operating units is detected by the operating-capacity variation detection portion (74), and adjusts the opening degree of the second outdoor control valve (17) to suppress a rise of pressure of the refrigerant flowing into the operating unit.

An air conditioner includes a refrigerant circuit which connects an outdoor circuit and a plurality of indoor circuits connected in parallel. The air conditioner includes a leak detection section which detects leak of a refrigerant from the indoor circuits, and a control section which circulates the refrigerant to perform a refrigeration cycle when the leak detection section detects leak of the refrigerant such that the refrigerant in the indoor circuits of the refrigerant circuit is at a low pressure. Providing the control section in the air conditioner can reduce the leak of the refrigerant from the indoor circuit at low cost.

If the refrigerant amount balance control is executed, since degrees of opening of indoor expansion valves are narrowed in indoor units whose refrigerant superheating degrees are smaller than an average refrigerant superheating degree, amounts of refrigerant flowing into the indoor expansion valves are decreased. On the other hand, in the indoor unit where the refrigerant superheating degree is higher than the average refrigerant superheating degree, since refrigerant pressure on a downstream side of the indoor expansion valve is also decreased due to the degrees of opening of the indoor expansion valves being narrowed, the difference in pressure between the upstream side and the downstream side of the indoor expansion valve increases and an amount of refrigerant flowing into the indoor unit is increased. Accordingly, cooling ability of the indoor unit increases.