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 cooling system drains oil from low side heat exchangers to vessels and then uses compressed refrigerant to push the oil in the vessels back towards a compressor. Generally, the cooling system operates in three different modes of operation: a normal mode, an oil drain mode, and an oil return mode. During the normal mode, a primary refrigerant is cycled to cool one or more secondary refrigerants. As the primary refrigerant is cycled, oil from a compressor may mix with the primary refrigerant and become stuck in a low side heat exchanger. During the oil drain mode, the oil in the low side heat exchanger is allowed to drain into a vessel. During the oil return mode, compressed refrigerant is directed to the vessel to push the oil in the vessel back towards a compressor.

Methods and systems are provided for an air conditioning system. An example method of determining current through a compressor suction valve in a vehicle air conditioning (AC) system is provided, the AC system comprises an evaporator fan and the method includes determining the speed of the evaporator fan and determining the current through the suction valve based on the speed of the evaporator fan.

A heat exchange system and a method for determining whether flow of cooling medium passing through a heat exchanger is too low. The heat exchange system includes a refrigerant flow path in which refrigerant circulates; a cooling medium flow path in which cooling medium circulates; and a heat exchanger connected to both the refrigerant flow path and the cooling medium flow path so that the refrigerant and the cooling medium exchange heat in the heat exchanger. The heat exchange system includes a first temperature sensor arranged at a cooling medium inlet of the heat exchanger, a second temperature sensor at a cooling medium outlet of the heat exchanger, and a controller in communication with the first temperature sensor and the second temperature sensor. The controller is configured to determine whether the flow of cooling medium in the heat exchanger is too low based on a temperature difference.

A cooling system drains oil from low side heat exchangers to vessels and then uses compressed refrigerant to push the oil in the vessels back towards a compressor. Generally, the cooling system operates any number and combination of three different modes of operation: a normal mode, an oil drain mode, and an oil return mode. During the normal mode, a primary refrigerant is cycled to cool one or more secondary refrigerants. As the primary refrigerant is cycled, oil from a compressor may mix with the primary refrigerant and become stuck in a low side heat exchanger. During the oil drain mode, the oil in the low side heat exchanger is allowed to drain into a vessel. During the oil return mode, compressed refrigerant is directed to the vessel to push the oil in the vessel back towards a compressor.

A heat transfer system that includes one or more heat exchangers and one or more variable control pumps that control flow through the one or more heat exchangers. At least one variable control pump is on the source side of the heat exchanger for controlling flow of a first circulation medium and at least one flow controlling mechanical device is on the load side of the heat exchanger for controlling flow of a second circulation medium. Sensors are used for detecting variables of the first circulation medium and the second circulation medium. At least one controller is configured to control at least one parameter of the first circulation medium or the second circulation medium by controlling at least one of the variable control pump or the flow controlling mechanical device using a feed forward control loop calculated from the detected variables to achieve control of the at least one parameter.

A method for cooling a mixed beverage formed with one or more beverage components includes circulating a refrigerant through a heat exchanger having a phase change material to cool a beverage component and sensing a temperature of the refrigerant. The method further includes detecting a first instance when the sensed temperature of the refrigerant equals a threshold refrigerant temperature, detecting a second instance when the sensed temperature of the refrigerant equals the threshold refrigerant temperature, and stopping circulation of the refrigerant when the second instance is detected.

An evaporator apparatus for a refrigeration cycle of an HVAC system or a refrigeration system is disclosed that includes: a primary evaporator pathway for a working fluid of the refrigeration cycle extending through a primary expansion device and a primary evaporator; a secondary evaporator pathway for the working fluid in parallel with the primary evaporator pathway and extending through a secondary expansion device and a secondary evaporator; a coolant circuit for cooling a device, the secondary evaporator configured for heat exchange between the working fluid and process fluid of the coolant circuit; and a controller configured to control: the primary expansion device to maintain a target superheat of working fluid at a primary control location downstream of the primary evaporator; and the secondary expansion device based on monitoring a temperature of process fluid to maintain a target temperature of process fluid at a coolant control location in the coolant circuit.

An air conditioner comprises: a refrigerant circuit configured to circulate refrigerant through a compressor, a condenser, an LEV and an evaporator; a first temperature sensor configured to sense the temperature of liquid refrigerant at the inlet port of the evaporator; and a controller configured to control the compressor and the LEV. In a case where a temperature sensed by the first temperature sensor is lower than a frosting reference temperature, the controller increases the opening degree of the LEV and also increases the operating frequency of the compressor as compared with a case where the temperature sensed by the first temperature sensor is higher than the frosting reference temperature.

The refrigeration cycle apparatus includes a refrigerant circuit, a controller to control the refrigerant circuit, a bypass flow path, and a flow control valve. The bypass flow path communicates between the discharge side of the compressor and the first outdoor heat exchanger or between the discharge side of the compressor and the second outdoor heat exchanger. The flow control valve is provided to the bypass flow path. The refrigerant circuit is configured to be able to perform a heating defrosting simultaneous operation. The heating defrosting simultaneous operation is an operation of supplying part of the refrigerant discharged from the compressor to one of the first outdoor heat exchanger and the second outdoor heat exchanger via the bypass flow path, causing the other of the first outdoor heat exchanger and the second outdoor heat exchanger to serve as an evaporator, and causing the indoor heat exchanger to serve as a condenser.