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 refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port.

No studies have been made regarding what kinds of refrigerants should be used in a refrigeration cycle device for a vehicle. An air conditioner (1) for a vehicle includes a refrigerant circuit (10) and a refrigerant that is sealed in the refrigerant circuit (10). The refrigerant circuit (10) includes a compressor (80), a first heat exchanger (85), which serves as a heat dissipater in a dehumidifying heating mode, an outside-air heat exchanger (82), a cooling control valve (87), and a second heat exchanger (86), which serves as an evaporator in the dehumidifying heating mode. The refrigerant is a refrigerant having a low GWP.

An HVAC system includes an evaporator. The evaporator includes a sensor configured to measure a property value (i.e., a saturated suction temperature or a saturated suction pressure) associated with saturated refrigerant flowing through the evaporator. The system includes a variable-speed compressor configured to receive the refrigerant and compress the received refrigerant. The system includes a controller communicatively coupled to the sensor and the variable-speed compressor. The controller monitors the property value measured by the sensor and detects a system fault, based on the monitored property value. In response to detecting the system fault, the controller operates the compressor in a freeze-prevention mode, which is configured to maintain the property value above a setpoint value by adjusting a speed of the variable-speed compressor. This prevents or delays freezing of the evaporator during operation of the system during the detected system fault.

An EXV (electronic expansion valve) control system includes an EXV controller for controlling an EXV within the refrigerant loop of an HVAC system. The EXV controller implements a master control algorithm that includes a plurality of sub-control algorithms and an initial series of branching decision points to determine the current mode of operation and to execute select sub-control algorithms corresponding to the current mode of operation, while not executing the sub-control algorithms corresponding to the other modes of operation. The sub-control algorithms implement various combinations of PID (Proportional Integral Derivative) control and feed-forward control, the results of which can be mapped to specific control instructions for the EXV.

A heat transfer apparatus includes a plurality of “n” number of control valves, each of the plurality of “n” number of control valves including a control valve inlet and a control valve outlet; a like plurality of “n” number of evaporator sections, each of the like plurality of “n” number of evaporator sections including an evaporator section inlet and an evaporator section outlet, each evaporator section inlet fluidly coupled to a corresponding one of the plurality of “n” number of control valve outlets, each evaporator section configured to extract heat from at least one heat load that is in thermal conductive or convective contact or proximate to the evaporator section; a refrigerant fluid inlet fluidly coupled to the like plurality of evaporator sections; and a refrigerant fluid outlet fluidly coupled to the like plurality of evaporator sections.

A refrigerant cycle device includes a compressor, a radiator, a first expansion valve, a second expansion valve, a first evaporator, a second evaporator, and a controller. The controller is configured to switch between a first evaporator priority control and a second evaporator priority control. During the first evaporator priority control, the controller controls a throttle opening of the second expansion valve based on at least one of a temperature of a first evaporator, a temperature of a refrigerant flowing through the first evaporator, and a temperature of an air having exchanged heat in the first evaporator. During the second evaporator priority mode, the controller controls the throttle opening based on a refrigerant state of the second evaporator. When the at least one of the temperatures is equal to or greater than a switching temperature, the second priority mode is switched to the first priority mode.

A system for controlling or optimizing the performance of a vapor compression system by modifying the actuator commands via an output interface, that realizes thermofluid property functions and their derivatives as spline functions which are represented in a coordinate system that is aligned with a fluid saturation curve. The system includes an interface configured to receive measurement data from sensors, a memory configured to store thermofluid property data and computer-executable programs including a B-spline method, and a processor for performing the computer-implemented method. The processor is configured to take as input two thermofluid property variables, and compute a coordinate transformation in which one axis of the coordinates is aligned with the liquid and vapor saturation curves. In the saturation-curve aligned coordinates, a spline function represents the thermofluid property function, with coefficients and knots stored in memory. The spline function is constructed in a manner such that derivatives of the thermofluid property function may be discontinuous across the saturation curve.

A method of detecting electrical failure in a refrigeration system is provided. The method includes determining whether a present superheat of the refrigeration system is between a maximum superheat and a minimum superheat for the refrigeration system, the maximum superheat and the minimum superheat defining a normal operating range. The method also includes detecting an electrical property of an expansion valve assembly of the refrigeration system responsive to the superheat being outside the normal operating range. The method further includes determining whether the expansion valve assembly as experienced an electrical failure based on at least the electrical property. A signal indicating that the expansion valve has experienced an electrical failure is generated based on a determination that the expansion valve assembly has experienced the electrical failure.

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.