An HVAC system with a refrigerant gas sensor is provided. In one embodiment, an HVAC system includes a heat exchanger coil installed within a housing. The heat exchanger coil is operable to exchange heat with air in the housing via a refrigerant passing through the heat exchanger coil. The system also includes an HVAC sensor assembly installed within the housing. The HVAC sensor assembly includes a refrigerant gas sensor and an orientation sensor positioned to detect an orientation of the refrigerant gas sensor. The HVAC system may also or instead include a position sensor to detect the position of the refrigerant gas sensor within the system. Additional systems, devices, and methods are also disclosed.

A water regulator includes a water regulation valve, a first temperature sensor, a second temperature sensor, and a controller. The water regulation valve regulates a quantity of water flowing through water pipes. The first temperature sensor measures a temperature of one of the water pipes which is connected to an inlet of a heat exchanger. The second temperature sensor measures a temperature of one of the water pipes which is connected to an outlet of the heat exchanger. The controller controls an opening degree of the water regulation valve, based on a difference between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor.

Provided is an air-conditioning apparatus including a plurality of indoor units for an outdoor unit, which is capable of determining whether there is occurrence of frost formation on the outdoor unit during a heating operation so as to enable a transition to a defrosting operation at an appropriate timing. Each of the indoor units is configured to transmit an operating-state notification for notifying a self-operating state to the outdoor unit. The outdoor unit is configured to determine the number of indoor units performing the heating operation among the plurality of indoor units based on the operating-state notifications, and determine the occurrence of the frost formation after elapse of a preset time period from a time at which the number of the indoor units performing the heating operation changes.

An air-conditioning apparatus includes a refrigerant circuit formed by connecting, with pipes, a compressor, a first refrigerant flow switching device, a heat-source-side heat exchanger, an expansion device, and a plurality of intermediate heat exchangers. A heat medium circuit is formed by connecting, with pipes, a plurality of pumps configured to pressurize and circulate the heat medium subjected to heat exchange in the plurality of intermediate heat exchangers, a plurality of use-side heat exchangers each configured to exchange heat between the heat medium and air in an air-conditioned space, and a heat-medium flow switching/control device configured to switch which of the heat medium is to be allowed to flow into and out of each of the use-side heat exchangers; and a controller configured to perform processing for controlling the switching performed by the heat-medium flow switching/control device, in accordance with a capacity of each of the use-side heat exchangers.

An air conditioning apparatus uses R32 as a refrigerant, and includes a compressor, a condenser, an expansion mechanism, an evaporator, an intermediate injection channel, a suction injection channel, a switching mechanism, a branch flow channel, first and second injection opening adjustable valves, an injection heat exchanger, a refrigerant storage tank, a bypass channel, and a control part. The switching mechanism switches between an intermediate injection condition in which refrigerant flows in the intermediate injection channel, and a suction injection condition in which refrigerant flows in the suction injection channel. The branch flow channel branches from a main refrigerant channel which joins the condenser and the evaporator, and guides the refrigerant to the intermediate injection channel and the suction injection channel. The bypass channel guides a gas component of the refrigerant accumulated inside the refrigerant storage tank to the intermediate injection channel and the suction injection channel.

The refrigerant circulation direction is switched between first and second circulation directions. In the first circulation direction, the refrigerant is circulated in order of a first heat exchanger, a compressor, a second heat exchanger, and a first decompressor, and circulated in order of the first heat exchanger, the compressor, a third heat exchanger, and a second decompressor. A controller identifies a specific heat exchanger from among the second heat exchanger and the third heat exchanger. When an elapsed time from activation of the compressor is shorter than a reference time, the controller makes an opening degree of a specific decompressor that communicates with the specific heat exchanger larger than an opening degree of the decompressor that is among the first decompressor and the second decompressor and different from the specific decompressor, and sets the refrigerant circulation direction to the second circulation direction opposite to the first circulation.

To avoid decline in the efficiency of a compressor at a low load, a thermal storage air conditioner has a refrigerant circuit (11) which has a compressor (22), an outdoor heat exchanger (23), and an indoor heat exchanger (72) and performs a refrigeration cycle, and a thermal storage section (60) which has a thermal storage medium and exchanges heat between the thermal storage medium and a refrigerant of the refrigerant circuit (11). The thermal storage air conditioner performs a simple cooling operation in which in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72), and a cooling and cold thermal energy storage operation in which in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72), and in which the thermal storage medium in the thermal storage section (60) is cooled by the refrigerant. The thermal storage air conditioner has an operation control section (100) which, if a rotational speed of the compressor (22) is slowed down to a predetermined lower reference value in the simple cooling operation, switches an operation of the thermal storage air conditioner from the simple cooling operation to the cooling and cold thermal energy storage operation to increase the rotational speed of the compressor (22).

An air conditioning system includes a storage medium and an air conditioning system, for a three-pipe air conditioning system, the three-pipe air conditioning system includes a compressor, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator, a first pipeline, a second pipeline and a third pipeline; the oil return control method comprises the following steps: controlling the compressor to operate at a first frequency in a refrigerating mode; judging whether the operation duration of the refrigerating mode reaches a first preset time or not; if so, the air conditioning system enters an oil return state, and the compressor, the third pipeline, the second pipeline and the gas-liquid separator are controlled to be communicated in sequence to form a refrigerant circulation loop.

Provided is a first unit including a first unit including a compressor and a first heat exchanger; a plurality of second units each including a second heat exchanger and each being connected to the first unit via a plurality of branched pipes; a plurality of valves configured to open to permit refrigerant flows and close to not permit the refrigerant flows; a storage unit configured to store connection information indicating a relationship of connection between the plurality of second units and the plurality of pipes; a closed path pipe that is any of the plurality of branched pipes to which no second unit is connected, and a control unit configured to detect whether the closed path pipe is included in the connection information.

An outdoor unit of the heat pump includes a compressor, an oil separator provided in a discharge path of the compressor, an outdoor-unit connecting pipe connecting an intake path of the compressor and an outdoor unit of an another heat pump for supplying a refrigerant to the outdoor unit of the another heat pump, an oil supply pipe extending from a predetermined position of the oil separator and connecting to the outdoor-unit connecting pipe, an on-off valve provided on the oil supply pipe, an expansion valve provided in a portion of the outdoor-unit connecting pipe between a connecting part connected to the intake path and a connecting part connected to the oil supply pipe, and a refrigerant filling port provided in a portion of the outdoor-unit connecting pipe between the connecting part and the expansion valve.