Various methods and apparatuses are provided for monitoring and detecting gas leaks. A method of determining a gas leak with a sensor assembly is provided. The sensor assembly includes a primary sensing device and a reference sensing device. The method includes receiving, via the primary sensing device, a first oxygen concentration level reading of a given area. The method also includes receiving, via the reference sensing device, a second oxygen concentration level reading of the given area. The method further includes comparing the first oxygen concentration level reading and the second oxygen concentration level reading. Based on the comparison, the method still further includes causing a transmission of a signal that a gas leak is occurring in an instance in which the first oxygen concentration level reading and the second oxygen concentration level reading have a difference greater than a threshold difference. A corresponding gas detection apparatus is also provided.

A refrigerant cycle apparatus, that circulates a flammable refrigerant in a refrigerant circuit, includes: a gas-side cutoff valve; a liquid-side cutoff valve, where the gas-side cutoff valve and the liquid-side cutoff valve are disposed on opposite sides of a first portion of the refrigerant circuit; a detection unit that detects refrigerant leakage from the first portion into a predetermined space; and a control unit that sets a cutoff state in the gas-side cutoff valve and the liquid-side cutoff valve when the detection unit detects the refrigerant leakage from the first portion into the predetermined space. The cutoff leakage rate at the gas-side cutoff valve is higher than the cutoff leakage rate at the liquid-side cutoff valve.

A refrigerant leakage detection sensor for a heat pump includes a sensor casing, a circuit board enclosed by the sensor casing, and a gas sensor mounted on the circuit board. The gas sensor has a housing, a refrigerant reception area at an end of the housing allowing gaseous refrigerant to enter the housing, and a sensing element in the housing. The housing protrudes through an opening in the sensor casing so that the refrigerant reception area is arranged outside the sensor casing and the sensing element is positioned inside the sensor casing.

Provided is a heat pump system having a liquid-side on-off valve, a gas-side on-off valve, an ambient temperature detector configured to detect temperature of fluid which passes through a heatsource-side heat exchanger, and a controller. The controller is configured to perform a refrigerant recovery operation for recovering refrigerant from a utilization-side piping section to a heatsource-side piping section by operating a compressor while the liquid-side on-off valve is closed and the gas-side on-off valve is open, and control the compressor such that, when the ambient temperature is higher than or equal to a predetermined value, increase rate of compressor rotation speed is low compared with that of when the ambient temperature is lower than the predetermined value.

One or more example embodiments provide a vending machine (105) that detects refrigerant leaks. The vending machine includes a main cabinet (605), a sensor circuit (615), and control equipment (830). The sensor circuit is configured to detect a refrigerant leaked in the main cabinet. The control equipment is configured to operate a component (620) of the refrigerated vending machine based on the detected refrigerant.

A gas detector is provided and includes a gas detector element, electronics to interface with the gas detector element and an enclosure configured to expose the gas detector element to an exterior and to form an electronics housing area in which the electronics are disposed whereby the electronics are isolated from the exterior.

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.

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.

An air conditioner including: a compressor; a heat exchanger fluidly connected to the compressor; a pressure sensor provided in a first flow path connecting an outlet of the compressor to an inlet of the first heat exchanger; a temperature sensor provided in a second flow path connected to an outlet of the heat exchanger; and a processor connected to the compressor, the pressure sensor, and the temperature sensor. The processor configured to: acquire a reference index value based on a first reference pressure measured by the pressure sensor and a first reference temperature measured by the temperature sensor, acquire a measurement index value based on a first measurement pressure measured by the pressure sensor and a first measurement temperature measured by the temperature sensor, and display a shortage of a refrigerant of the air conditioner based on the reference index value and the measurement index value.

A system for charging an outdoor unit with refrigerant includes a sensor configured to measure a refrigerant concentration and a user device configured to receive the measured refrigerant concentration. The system includes that the user device is configured to, in response to the measured refrigerant concentration exceeding a threshold, generate and display an alert on a user interface of the user device indicating the measured refrigerant concentration exceeds the threshold.