An air conditioner includes a heat source unit having a compressor, a first heat exchanger configured to cause heat exchange between a refrigerant and liquid fluid, a second heat exchanger configured to cause heat exchange between the refrigerant and air, and a valve configured to switch to supply or not to supply the second heat exchanger with the refrigerant, and a controller configured to control to operate the compressor and to open or close the valve. The controller opens the valve to supply the second heat exchanger with the refrigerant to cause the second heat exchanger to function as a heat absorber when assessing that the refrigerant sent to the utilization unit needs to be decreased in quantity during cooling operation in which the first heat exchanger functions as a radiator.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

Disclosed is a cascade air conditioner system. The cascade air conditioner system includes a compressor (1) having a first gas outlet (11), a second gas outlet (12) and a gas inlet (13); a flash tank (2) having a first flash evaporation port (21), a second flash evaporation port (22), a third flash evaporation port (23), and a fourth flash evaporation port (24); and a condenser evaporator (3) having a first port (31), a second port (32), a third port (33), and a fourth port (34), wherein a first heat exchanger (41) is connected in series between the first gas outlet (11) and the first flash evaporation port (21), the second flash evaporation port (22) is connected via a pipe with the first port (31), the second gas outlet (12) is connected via a pipe with the fourth flash evaporation port (24), the third flash evaporation port (23) is connected via a pipe with an inlet of a first throttle element (51), an outlet of the first throttle element (51) is connected via a pipe with a second heat exchanger (42) and is connected via a pipe with the third port (33), the second heat exchanger (42) is also connected via a pipe with the second port (32) through a second throttle element (52), and the fourth port (34) is connected via a pipe with the gas inlet (13). In the cascade air conditioner system, a gas-phase refrigerant in the compressor (1) is introduced to the flash tank (2), such that the degree of dryness in the flash tank (2) can be controlled conveniently, thereby enhancing performances of the system.

A refrigeration system includes a rotary pressure exchanger fluidly coupled to a low pressure branch and a high pressure branch. The rotary pressure exchanger is configured to receive the refrigerant at high pressure from the high pressure branch, to receive the refrigerant at low pressure from the low pressure branch, and to exchange pressure between the refrigerant at high pressure and the refrigerant at low pressure, and wherein a first exiting stream from the rotary pressure exchanger includes the refrigerant at high pressure in the supercritical state or the subcritical state and a second exiting stream from the rotary pressure exchanger includes the refrigerant at low pressure in the liquid state or the two-phase mixture of liquid and vapor.

An evaporator coil system includes a segmented evaporator coil. The segmented evaporator coil includes a primary segment and a secondary segment. A first plurality of evaporator circuit lines are fluidly coupled to the primary segment and a second plurality of evaporator circuit lines are fluidly coupled to the secondary segment. A suction line includes a first connection fluidly coupled to the primary segment and a second connection fluidly coupled to the secondary segment. A valve is arranged in fluid communication with the secondary segment so as to selectively restrict refrigerant flow through the secondary segment.

Disclosed is a cascade air conditioner system. The cascade air conditioner system includes a compressor (1) having a first gas outlet (11), a second gas outlet (12) and a gas inlet (13); a flash tank (2) having a first flash evaporation port (21), a second flash evaporation port (22), a third flash evaporation port (23), and a fourth flash evaporation port (24); and a condenser evaporator (3) having a first port (31), a second port (32), a third port (33), and a fourth port (34), wherein a first heat exchanger (41) is connected in series between the first gas outlet (11) and the first flash evaporation port (21), the second flash evaporation port (22) is connected via a pipe with the first port (31), the second gas outlet (12) is connected via a pipe with the fourth flash evaporation port (24), the third flash evaporation port (23) is connected via a pipe with an inlet of a first throttle element (51), an outlet of the first throttle element (51) is connected via a pipe with a second heat exchanger (42) and is connected via a pipe with the third port (33), the second heat exchanger (42) is also connected via a pipe with the second port (32) through a second throttle element (52), and the fourth port (34) is connected via a pipe with the gas inlet (13). In the cascade air conditioner system, a gas-phase refrigerant in the compressor (1) is introduced to the flash tank (2), such that the degree of dryness in the flash tank (2) can be controlled conveniently, thereby enhancing performances of the system.

An air-conditioning apparatus includes a first indoor unit and an outdoor unit in a single refrigeration cycle and connected via a first refrigerant pipe. The first indoor unit is provided with a first refrigerant leakage sensor configured to detect leakage of refrigerant and a concentration of leaked refrigerant, and the outdoor unit includes a compressor, a first flow control valve configured to adjust a flow rate of the refrigerant flowing through the first refrigerant pipe, and a control unit configured to stop the compressor and fully close the first flow control valve when leakage of the refrigerant flowing through the first refrigerant pipe is detected by the first refrigerant leakage sensor, and configured to change an opening speed of the first flow control valve to a speed less than an opening speed of the first flow control valve adopted before the leakage of the refrigerant is detected.

An air conditioning device has: a refrigerant circuit that is formed of a compressor, a switching valve, a cascade heat exchanger, an expansion valve and an outdoor heat exchanger connected to one another by a first pipe through which a refrigerant flows, and capable of performing a defrosting operation in which the refrigerant discharged from the compressor is introduced into the outdoor heat exchanger; a heat-transfer medium circuit that is formed of a pump, the cascade heat exchanger, and the indoor heat exchanger connected to one another by a second pipe through which a heat-transfer medium flows; and a control device that controls the compressor and the pump. When an amount of heat storage of the heat-transfer medium is less than a threshold, the control device reduces the heating capability of the indoor heat exchanger when the air conditioning device transitions from a heating operation to the defrosting operation.

Purge systems for heating, ventilation, air conditioning, and refrigeration (HVACR) circuits in chillers can use adsorbent and/or membranes to separate refrigerant from non-condensable gases, allowing the non-condensables to be exhausted while the working fluid can be recovered and returned to the HVACR circuit. The purge systems can include one or more separation chambers including either an adsorbent material or a selectively permeable membrane. The selectively permeable membrane can be solubility-based for its selectivity. Optionally, a pusher pump can be upstream of the separation chambers to pressurize the purge gas through the purge system, including in the separation chamber. The purge system can be controlled using a model correlating pressure differentials in the purge system with purge gas conditions such as non-condensable and working fluid concentrations.

A system utilizing cascading heat pump circuits (HPCs) is employed to efficiently transfer heat from low temperature reservoirs to high temperature reservoirs. The system of cascading (e.g., multistage) HPCs include at least two HPCs that are in thermal communication. The first HPC uses a first refrigerant and is configured to raise a first cold operating temperature to a first hot operating temperature. The second HPC uses a second refrigerant and is configured to raise a second cold operating temperature to a second hot operating temperature. The second HPC is in thermal communication with the first HPC through a thermal exchange block, which allows the transfer of heat between the HPCs and causes the first hot temperature to be equilibrated with the second cold temperature. The cascading HPC system also includes a system controller that is configured to optimize the coefficient of performance (COP) of the cascading HPC system.