A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, and a secondary condenser. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the primary condenser.

A refrigeration cycle apparatus includes a refrigerant circuit, by pipes, connecting a compressor, a flow switching device, a first heat exchanger, an expansion device, and a second heat exchanger. As refrigerant to be circulated through the refrigerant circuit, any one of a refrigerant having saturated gas temperature under standard atmospheric pressure that is higher than that of R32 and a refrigerant mixture mainly composed of the refrigerant is used. The refrigerant circuit includes an internal heat exchanger configured to exchange heat between the refrigerant flowing through a refrigerant-inlet side of the second heat exchanger and the refrigerant flowing through a refrigerant-outlet side of the second heat exchanger.

A valve device includes a housing integrally or separately having a flow path formation part where at least one flow path hole through which a fluid passes is formed. The valve device includes: a drive part that outputs a rotational force; and a rotation part that rotates about a predetermined axis by the rotational force output from the drive part. The rotation part includes a shaft and a rotor increasing or decreasing an opening degree of the flow path hole with rotation of the shaft. The rotor has a sliding surface that slides while facing an opening surface of the flow path formation part where the flow path hole is opened. At least a part of the rotation part is rotatably held by the housing.

In an embodiment, a method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system is performed by a controller in the HVAC system. The method includes determining a reference saturated suction temperate (SST) via a sensor disposed in relation to an evaporator coil in the HVAC system. The method also includes determining whether the reference SST is below a minimum SST threshold. The method also includes, responsive to a determination that the reference SST is below the minimum SST threshold, increasing a discharge air temperature (DAT) setpoint.

The disclosure describes a system that includes an evaporator, an accumulator downstream of the evaporator, a centrifugal compressor downstream of the accumulator, a first heat exchanger stage downstream of the centrifugal compressor, and a second heat exchanger stage downstream of the first heat exchanger stage. The evaporator is configured to cool a conditioned air stream using a refrigerant. The accumulator is configured to store excess refrigerant. The centrifugal compressor is configured to compress the refrigerant. The first heat exchanger stage is configured to cool the refrigerant using environmental air. The second heat exchanger stage is configured to cool the refrigerant from the first heat exchanger stage using a portion of the excess refrigerant from the accumulator.

A method for preventing formation of droplets in a heat exchanger, in which a second medium transfers heat to a first. The method is performed by a controller which receives different temperature values (T.sub.1, T.sub.2, T.sub.3) and a pressure (P) value to be used for calculating a boiling point temperature value (T.sub.B) and determining a first temperature difference (ΔT.sub.1) and a second temperature difference (ΔT.sub.2). Generating a flow control signal, for controlling the flow of the first medium into the heat exchanger, based on the first temperature difference (ΔT.sub.1), the second temperature difference (ΔT.sub.2) and the first temperature value T.sub.1 and sending the flow control signal to a regulator device for controlling the flow of the first medium in the heat exchanger.

A cooling system including a vaporizer configured to absorb heat due to a liquid-phase refrigerant being vaporized, a condenser configured to discharge heat due to a refrigerant in a gaseous phase state being liquefied, a resistance body provided in a middle of a pipe passage ranging from the vaporizer to the condenser and applying a resistance to the refrigerant, state detection sensors provided in the pipe passage on an upstream and downstream sides of the resistance body and detecting a state of the refrigerant flowing through each side inside the pipe passage, and a flow rate controller configured to detect droplets in the refrigerant flowing through the pipe passage on the basis of a difference between detection values of the state detection sensors which are detected on the upstream and downstream sides of the resistance body, and controls a flow rate of the refrigerant on the basis of detection results.

A heating, ventilating, and air conditioning (HVAC) system that includes a vapor compression system having a refrigerant, a compressor of the vapor compression system configured to circulate the refrigerant through the vapor compression system, an expansion device of the vapor compression system configured to adjust a flow of the refrigerant through the vapor compression system, and a controller configured to adjust a position of the expansion device based on a measured amount of superheat of the refrigerant entering the compressor, a measured discharge temperature of the refrigerant leaving the compressor, or a combination thereof, such that the measured amount of superheat of the refrigerant entering the compressor reaches a target amount of superheat, the measured discharge temperature of the refrigerant leaving the compressor reaches a target discharge temperature, or a combination thereof.

A controller for a refrigeration system includes a processing circuit having one or more processors and memory. The processing circuit is configured to calculate a superheat of a gas refrigerant exiting a first side of a subcooler based on a measured temperature and a measured pressure of the gas refrigerant and compare the calculated superheat to a superheat threshold. In response to a determination that the calculated superheat is less than the superheat threshold, the processing circuit closes an expansion valve to restrict a flow of the gas refrigerant through a second side of the subcooler. In response to a determination that the calculated superheat is equal to or greater than the superheat threshold, the processing circuit operates the expansion valve to drive a temperature of a subcooled liquid refrigerant exiting the second side of the subcooler to a subcooled liquid temperature setpoint.

An ice making system includes: a refrigerant circuit that performs a vapor compression refrigeration cycle and that includes a compressor, a condenser that condenses refrigerant discharged from the compressor, a first expansion valve with an adjustable opening degree that decompresses the refrigerant from the condenser, a flooded evaporator that evaporates the refrigerant decompressed by the first expansion valve, and a superheater that imparts a degree of superheating to the refrigerant discharged from the flooded evaporator; a circulation circuit that circulates a medium that is cooled by the flooded evaporator; and a control device that controls the adjustable opening degree of the first expansion valve such that the superheater imparts to the refrigerant discharged from the flooded evaporator a degree of superheating at which dryness of the refrigerant is kept within a predetermined range of less than 1.