Devices, systems, and methods are disclosed for cooling using both air and/or liquid cooling sub circuits. A vapor compression cooling system having both an air and liquid cooling sub circuit designed to service high sensible process heat loads that cannot be solely cooled by either liquid or air is provided.

A method of operating a heat exchanger system in which a compressor, which is drivable by a motor, is fluidly interposed between an evaporator and a condenser following receipt of a shutdown command is provided. The method includes positioning inlet guide vanes (IGVs) of the compressor in a first position in the event of at least one of a first precondition being in effect and the first and a second precondition both not being in effect. The method further includes positioning the IGVs in a second position in an event the first precondition is not in effect but the second precondition is in effect, ramping a speed of the compressor down until a third precondition takes effect, removing power from the motor and positioning the IGVs in the first position once power is removed from the motor.

A chiller includes an evaporator, a compressor including a prime mover, a first pressure sensor that detects a first pressure in the evaporator, a second pressure sensor that detects a second pressure in a condenser, and a controller. The controller determines a predicted energy level of the compressor based on the first pressure and the second pressure, the predicted energy level associated with liquid droplet flow into the compressor, compares the predicted energy level to an operating energy level, and modifies the at least one of the input power and the input current to the prime mover based on the comparison satisfying a modification condition.

Systems and methods for implementing ejector refrigeration cycles with cascaded evaporation stages that utilize a pump to optimize operation of the ejector and eliminate the need for a compressor between the evaporation stages.

A system and method for increasing the refrigeration capacity of a direct expansion refrigeration system having a vapor separator and a vapor ejector. After the throttling process at the expansion device, the mixture of liquid and vapor enters the inlet separator. The vapor separator generates vapor to power the ejector through flashing of warm refrigerant liquid from a higher temperature and pressure to a lower pressure. The cooler refrigerant liquid then goes to the evaporator coil inlet. Furthermore, the system stabilizes the superheat of the outlet vapor and reduces fluctuations in outlet superheat caused by excess unevaporated liquid flowing from the outlets of the tubes due to mal-distribution at the inlet.

An HVAC system is disclosed, comprising: (a) a compressor, (b) a source heat exchanger for exchanging heat with a source fluid, (c) a first load heat exchanger operable for heating/cooling air in a space, (d) a second load heat exchanger for heating water, (e) first and second reversing valves, (f) first and second 3-way valves, (f) a bi-directional electronic expansion valve, (g) a first bi-directional valve, and (h) a second bi-directional valve to modulate exchange of heat in the first load heat exchanger when operating as an evaporator and to control flashing of the refrigerant entering the source heat exchanger when operating as an evaporator, (h) a source pump for circulating the source fluid through the first load heat exchanger, (i) a water pump for circulating water through the second load heat exchanger, and (j) a controller to control operation of the foregoing.

Described is a regulation apparatus for a refrigeration plant having defined therein a refrigerant fluid path and a plurality of devices arranged along the refrigerant fluid path. The regulation apparatus includes a first sensor arranged in a first point (P1), and preferably a second sensor arranged in a second point (P3), both along the refrigerant fluid path. The control unit controls a first value measured by the first sensor and obtains a first regulation request of a device deriving from the first measured value as well as a second value measured by the second sensor, or calculated for the second point, and derives a second regulation request of the device deriving from the second measured value, compares the first and second regulation requests and establishes which regulation request is greater. A control unit commands an actuation device to actuate the most effective regulation request of the refrigeration plant devices.

Described is a regulation apparatus for a refrigeration plant having defined therein a refrigerant fluid path and a plurality of devices arranged along the refrigerant fluid path. The regulation apparatus includes a first sensor arranged in a first point (P1) and a second sensor arranged in a second point (P3), each along the fluid path of the refrigeration plant, a control unit and an actuation device. The control unit controls a first value measured by the first sensor and obtains a first regulation request deriving from the first measured value as well as a second value measured by the second sensor and derives a second regulation request deriving from the second measured value, compares the first and second regulation requests, and establishes which regulation request is greater. The control unit also commands the actuation device to actuate the most effective regulation request of the refrigeration plant devices.

A method for operating and controlling a vapor-compression cycle includes providing a system comprising an evaporator with a fan, a compressor, a condenser with a fan, an integrated expander, and a flash tank device with a vapor/liquid two-phase inlet and two outlets wherein a first outlet is a vapor outlet and a second outlet is a liquid outlet, and a metering valve; bringing a vapor-compression cycle up to steady-state at a fixed operating condition; opening the metering valve until the desired compressor suction superheat is achieved; and maintaining the desired degree of superheat by selectively increasing and decreasing superheat by reducing and increasing metering valve flow rate respectively.

When a controller receives an instruction for a heating operation, the controller switches an operation mode of a refrigeration cycle apparatus between a heating operation mode and an oil recovery operation mode. The heating operation mode is a mode to circulate refrigerant in a refrigerant circuit such that the refrigerant flows through a gas extension pipe in a gas phase state. The oil recovery operation mode is a mode to circulate the refrigerant in the refrigerant circuit such that the refrigerant flows in the gas extension pipe in a gas-liquid two-phase state. The direction in which the refrigerant flows in the gas extension pipe in the oil recovery operation mode is opposite to that in which the refrigerant flows in the gas extension pipe in the heating operation mode.