A hybrid air handler cooling unit has a bi-modal heat exchanger. In a direct expansion mode or a pumped refrigerant economization mode, the bi-modal heat exchanger is in a refrigerant path in parallel with first and second condenser coils and functions as a condenser coil. In a mixed direct expansion/pumped refrigerant economization mode, the bi-modal heat exchanger is in a refrigerant path in series between an outlet of a pump and an inlet of the first condenser coil and functions as a pre-cooler evaporator coil with return air first flowing across the bi-modal heat exchanger and then across an evaporator coil of an evaporator.

Provided are a refrigerator and a control method thereof. The refrigerator according to the embodiment includes a compressor configured to compress a refrigerant; a condenser configured to condense the refrigerant compressed by the compressor; a flow control part disposed at an exit side of the condenser to switch a flow direction of the refrigerant condensed by the condenser; a plurality of branch pipes configured to extend from the flow control part; an expander installed at the plurality of the branch pipes to depressurize the refrigerant; a plurality of evaporators connected to the plurality of branch pipes; and a bypass pipe configured to extend from an exit side of one of the plurality of evaporators to an entrance side of the other evaporator and having a bypass expander installed thereat to depressurize the refrigerant.

A thermal management system includes a closed dynamic cooling circuit, and a closed first steady-state cooling circuit. Each circuit has its own compressor, heat rejection exchanger, and expansion device. A thermal energy storage (TES) system is configured to receive a dynamic load and thermally couple the dynamic cooling circuit and the first steady-state cooling circuit. The dynamic cooling circuit is configured to cool the TES to fully absorb thermal energy received by the TES when a dynamic thermal load is ON, and the steady-state cooling circuit is configured to cool the TES when the dynamic thermal load is OFF.

A method for conditioning air in a test space of a test chamber which receives test material. A temperature in a range of −20° C. to +180° C. is established within the test space with a cooling device. The cooling device includes a cooling circuit with a refrigerant, a heat exchanger, a compressor, a condenser and an expansion element. An internal heat exchanger of the cooling circuit is connected to a high-pressure side of the cooling circuit upstream of the expansion element and downstream of the condenser and to a low-pressure side of the cooling circuit upstream of the compressor and downstream of the heat exchanger and is used to cool the refrigerant of the high-pressure side. A zeotropic refrigerant is used and the internal heat exchanger is used to cool the refrigerant of the high-pressure side to lower an evaporation temperature at the expansion element.

A cooling system for an aircraft includes a first cooling circuit having a first evaporator and a second evaporator, and a second cooling circuit having a third evaporator and a fourth evaporator. One of the first and second cooling circuits includes a first set of valves arranged to direct refrigerant through a first cooling sub-circuit, a second cooling sub-circuit, or both the first and second cooling sub-circuits based on ambient conditions. Two of the evaporators are installed on a first side of the aircraft, and the other two of the four evaporators are installed on a second side of the aircraft opposite the first side, and the first and second cooling circuits reject heat, via a heat exchanger, from their respective cooling circuit to air passing into an engine of the aircraft.

A cooling system is designed to generally allow for one or more compressors to be bypassed when ambient temperatures are low. The system includes a bypass line and valve that opens when ambient temperatures are low and/or when the pressure of the refrigerant in the system is low. In this manner, the refrigerant can flow through the bypass line instead of through one or more compressors. These compressors may then be shut off. To supply any needed pressure to cycle the refrigerant, the system may include a pump that turns on when the bypass line is open. When ambient temperatures are extremely low, thermosiphon may be used to cycle the refrigerant.

Refrigeration apparatus (1) having a closed circuit (C) in which a flow rate (P) of coolant circulates, said closed circuit comprising at least one main branch (M) provided with at least one main compressor (2), at least one cooling device (3) to cool said coolant, expansion means (4) to expand the coolant and at least one evaporator (5), said closed circuit further comprising at least one secondary economizer branch (100) for at least one fraction of flow rate (X1) of said coolant, wherein the inlet section (100a) of said at least one first secondary economizer branch (100) is arranged in a length (101) of said closed circuit (C) comprised between said cooling device (3) and said expansion means (4) and the outlet section (100b) of said at least one secondary economizer branch (100) is arranged in proximity of the suction of said main compressor (2), said main branch (M) further comprises at least one reciprocating compressor (6) arranged between said evaporator and said main compressor. Said at least one secondary economizer branch comprises at least one control device for diverting at least one portion (X2) of said fraction (X1) of coolant coming from said secondary economizer branch (100) to drive the reciprocating compressor.

A refrigeration system includes a receiver, a gas bypass valve, a parallel compressor, and a controller. The gas bypass valve and the parallel compressor are fluidly coupled to an outlet of the receiver in parallel and configured to control a pressure of a gas refrigerant in the receiver. The controller is configured to switch from operating the gas bypass valve to operating the parallel compressor to control the pressure of the gas refrigerant in the receiver in response to a value of a process variable crossing a switchover setpoint. The value of the process variable depends on an amount of the gas refrigerant produced by the refrigeration system. The controller is configured to automatically adjust the switchover setpoint in response to the amount of the gas refrigerant produced by the refrigeration system being insufficient to sustain operation of the parallel compressor.

A method for configuring a plurality of operating setpoints for a vapour compression system (1) is disclosed. The plurality of operating setpoints are divided into a first group (12) of operating setpoints to be generated manually and a second group (13) of operating setpoints to be generated automatically, and the operating setpoints are operated in accordance therewith. The manually generated operating setpoints (12) and the automatically generated operating setpoints (13) are provided to a setpoint manager (11), and the setpoint manager (11) checks if the provided operating setpoints (12, 13) are in compliance with a set of rules. In the case that at least some of the provided operating setpoints (12, 13) are not in compliance with the set of rules, the setpoint manager (11) adjusts at least some of the provided operating setpoints (12, 13) in accordance with the set of rules, thereby obtaining an adjusted set of operating setpoints. The vapour compression system (1) is subsequently controlled in accordance with the adjusted set of operating setpoints.

A refrigeration system includes a receiver, a gas bypass valve, a parallel compressor, and a controller. The gas bypass valve and the parallel compressor are fluidly coupled to an outlet of the receiver in parallel and configured to control a pressure of a gas refrigerant in the receiver. The controller is configured to switch from operating the gas bypass valve to operating the parallel compressor to control the pressure of the gas refrigerant in the receiver in response to a value of a process variable crossing a switchover setpoint. The value of the process variable depends on an amount of the gas refrigerant produced by the refrigeration system. The controller is configured to automatically adjust the switchover setpoint in response to the amount of the gas refrigerant produced by the refrigeration system being insufficient to sustain operation of the parallel compressor.