A heating ventilation and air conditioning (HVAC) control system. The HVAC control system includes a sensor that detects a refrigerant released from an HVAC system and emits a signal indicative of the detection. The HVAC control system also includes a switch that blocks a flow of electricity to an enclosed space and a controller that receives the signal from the sensor and activates the switch to block the flow of electricity in response to detection of the refrigerant.

A heat cycle system is a heat cycle system (1) using a working medium containing hydrofluoroolefin (HFO) that has a double bond in a molecule structure, the heat cycle system (1) having a compressor (10), a high-pressure side heat exchanger (12), a low-pressure side heat exchanger (14), an expansion mechanism (13), and an acid detection means (40) which is disposed in a discharge pipe (21) connecting the compressor (10) and the high-pressure side heat exchanger (12) and which detects acid generated by decomposition of the working medium in a heat cycle.

A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a compressor with a gas bearing supplied with compressed gas and a controller. The controller is configured to determine an inlet pressure and outlet pressure of the gas bearing, determine a maximum speed limit based on the inlet pressure and the outlet pressure, and prevent the compressor from operating at a speed that is greater than the maximum speed limit. A method of controlling a compressor includes calculating a maximum speed limit based on an inlet pressure and an outlet pressure of the gas bearing. The method also includes in response to determining that a speed setting is greater than the maximum speed limit, adjusting operation of the compressor such that a speed of the compressor is at or below the maximum speed limit.

The present disclosure relates to a heating, ventilation, and air conditioning (HVAC) system, and more particularly a method of detecting and mitigating refrigerant leaks in an HVAC system. The HVAC system includes a leak detection system for detecting a leak of the refrigerant from the refrigerant circuit. The leak detection system includes a collection chamber locatable proximate a component of the HVAC system. The leak detection system also includes a sensor assembly including an enclosure comprising a sensor and a fan. The leak detection system also includes a flowline connecting the collection chamber with the sensor assembly such that the sensor assembly may be located away from the collection chamber and the component. The fan is operable to induce fluid flow from the collection chamber into the sensor assembly and the sensor is operable to analyze the fluid flow and detect a leak of the refrigerant from the component.

A sensor assembly and a refrigerant sensing system for air conditioning systems can include a sensor controller, a sensor electrically connected to the sensor controller and configured to output sensor data to the sensor controller, and a housing having an interior space enclosing the sensor controller and the sensor. The housing includes a first end and a second end and a barrier disposed between the first end and the second end sealingly separating the interior space. The first end supports the sensor and includes a plurality of openings exposing the sensor to an external environment. The second end supports the sensor controller and substantially prevents the sensor controller from being exposed to the external environment.

An HVAC system includes an evaporator coil and a compressor fluidly coupled to the evaporator coil. A condenser coil is fluidly coupled to the compressor. The condenser coil includes at least one condenser circuit fluidly coupled between a discharge line and an exit manifold. A sub-cool circuit is fluidly coupled between the exit manifold and a liquid line. A first temperature sensor is disposed at an entrance to the sub-cool circuit. A second temperature sensor is disposed at an exit to the sub-cool circuit. An HVAC controller is operatively coupled to the first temperature sensor and the second temperature sensor. The HVAC controller is configured to determine a temperature difference across the sub-cool circuit.

A ceiling-mounted air conditioning indoor unit for a heat pump including a refrigerant circuit, the ceiling-mounted air conditioning indoor unit includes: a casing including an air inlet and an air outlet; a drain pan in a bottom portion of the casing; a heat exchanger in the refrigerant circuit that is disposed above the drain pan such that water dropping from the heat exchanger accumulates in the drain pan; a fan in the casing that draws air in from the air inlet, through the heat exchanger, and out of the air outlet; a bell mouth at the air inlet that guides the air drawn-in to the fan; a refrigerant leakage detection sensor that detects refrigerant leaking from the refrigerant circuit. The drain pan includes a first rim and a second rim.

An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

Example implementations relate to a leak mitigation (LM) system. The LM system may include a collection tank, a first valve unit coupled to the collection tank, a second valve unit coupled to a cooling loop carrying a coolant, and an LM pump coupled between the first valve unit and the second valve unit. Moreover, the leak mitigation system may also include a controller operatively coupled to the first valve unit, the second valve unit, and the LM pump to operate, in an event of a leak of the coolant from the cooling loop, the first valve unit, the second valve unit, and the LM pump to transfer at least a portion of the coolant to the collection tank from the cooling loop via the second valve unit and the first valve unit.

A refrigeration cycle apparatus includes a refrigeration cycle circuit that has a compressor, a condenser, an expansion device, and an evaporator that are connected through a pipe, the refrigeration cycle circuit being configured to allow refrigerant to circulate in the refrigeration cycle circuit, and a controller configured to determine whether the refrigerant leaks or whether the expansion device malfunctions on the basis of a degree of subcooling at an outlet of the condenser and a degree of superheat at an outlet of the evaporator or a degree of superheat at a suction port of the compressor.