A method for a refrigeration system according to an example of the present disclosure includes monitoring a performance characteristic of a refrigeration system, and based on the performance characteristic deviating from a predefined expected value by more than a predefined threshold: determining that the refrigeration system is leaking refrigerant, and operating a fan configured to pass air through a heat exchanger of the refrigeration system to dissipate the leaked refrigerant. A refrigeration system is also disclosed that is operable to detect and mitigate refrigerant leaks.

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 condenser coil of a system includes a subcool sensor. The subcool sensor includes a first thermistor positioned to sense a saturated liquid temperature of refrigerant flowing in a first portion of the condenser coil. The subcool sensor includes a second thermistor positioned to sense a liquid temperature of the refrigerant flowing in a second portion of the condenser coil. The second thermistor is coupled electronically in series with the first thermistor. The subcool sensor includes a signal output for transmitting a subcool signal from the subcool sensor. The signal output is coupled electronically to a first terminal of the first thermistor and a second terminal of the second thermistor. A controller of the system includes an input/output interface which receives the subcool signal from the subcool sensor and determines a temperature difference between the saturated liquid temperature and the liquid temperature based on the subcool signal.

A two temperature electronic expansion valve control for variable speed compressors that utilizes a correlation between airflow percentage and heat exchanger pressure drop to control the operation of an expansion valve. An indoor airflow percentage request may be communicated from an outdoor controller to an air handler controller. Using a correlation between airflow percentage and pressure drop across the heat exchanger, the airflow percentage may be used in predicting an outlet pressure of refrigerant exhausted from the heat exchanger. The predicted pressure drop may be used in determining a saturated temperature for the exhausted refrigerant. The determined saturated temperature may be compared to a sensed temperature of the refrigerant at the outlet of the heat exchanger to determine a superheat value, which is compared to a reference superheat value in determining the degree to open or close the expansion valve.

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 charge-verification tool is used with a charge-verification system to diagnose and remedy a charge condition. The charge-verification tool includes a device having a controller configured to communicate with a system controller in the charge-verification system and a display configured to display measurements and instructions to an installer. The device is a user interface and is configured to provide communication between the installer and the system controller in the charge-verification system. The controller prompts the installer to input charge-verification system information including refrigeration line length and diameter. The controller receives a subcooling temperature calculated by the system controller and determines whether the subcooling temperature is between a threshold and a target subcooling temperature. The controller displays an amount of charge to add to the charge-verification system based on whether the subcooling temperature is between the threshold and the target subcooling temperature.

An air-conditioning device including multiple outdoor units and an indoor unit through a pipe includes a control section that obtains a degree of supercooling at an outlet of a supercooling circuit of each outdoor unit based on a temperature detected by a temperature sensor that detects the temperature of refrigerant having passed through the supercooling circuit of each outdoor unit, obtain a target value of the degree of supercooling based on the obtained multiple degrees of supercooling, and perform the control of increasing the rotation speed of a compressor of an outdoor unit having a higher degree of supercooling than the target value and decreasing the rotation speed of a compressor of an outdoor unit having a lower degree of supercooling than the target value such that a difference in the degree of supercooling at the outlet of the supercooling circuit of each outdoor unit is decreased.

Provided is an air conditioner that can sufficiently increase a temperature of hot air when receiving a request for high-temperature air that temporarily increases the temperature of the hot air to be blown out. A refrigerant circuit has a first refrigerant path to which a compressor, a first utilization-side heat exchanger (121), a first expansion valve (131), and a heat source-side heat exchanger are connected in order. A control unit controls the compressor and the first expansion valve (131). When the control unit receives the request for high-temperature air that temporarily increases the temperature of the hot air blown out through the first utilization-side heat exchanger (121), the control unit changes the control of the first expansion valve (131) so that the temperature of a refrigerant that flows through the first utilization-side heat exchanger (121) increases.

The amount of refrigerant to be charged in a refrigerant circuit of an air conditioner is set to a range defined by a lower-limit charge amount and an upper-limit charge amount. The lower-limit charge amount is a charge amount with which a refrigerant supercooling degree is 0 deg and a refrigerant quality is 0 at a refrigerant outlet side of a supercooling heat exchanger when a cooling operation is performed under an overload condition in which the refrigerant is hardly condensed in an outdoor heat exchanger that functions as a condenser. On the other hand, the upper-limit charge amount is a charge amount with which a refrigerant supercooling degree is 0 deg and a refrigerant quality is 0 at a refrigerant outlet side of the outdoor heat exchanger when the cooling operation is performed under a rated condition.

A method of controlling fluid flow through a heating, ventilating, air conditioning, and refrigeration (HVAC-R) system includes measuring temperature and pressure at an outlet of an evaporator of the HVAC-R system, wherein the evaporator is in fluid communication with a compressor, a condenser, an expansion device between the evaporator and the condenser, and a flow control valve between the compressor and the condenser, and measuring a sub-cooling temperature at an outlet of the condenser. The measured evaporator temperature and pressure data is sent to a first superheat processor, and the measured sub-cooling temperature data is send to a second superheat processor. A control signal to the expansion device from the first superheat processor and a control signal to the flow control valve from the second superheat processor are then simultaneously sent.