Proposed is a method of controlling a gas heat-pump system, the system including an air conditioning module having a compressor and indoor and outdoor heat exchangers, and an engine module having an engine combusting mixed gas and thus generating drive power for operating the compressor, the method including: measuring factors that are temperature and humidity of outside air, an rpm of the engine, intake pressure, and an air-fuel ratio, the factors having effects on driving of the engine in an operating environment where the engine is driven; measuring a necessary ignition voltage for an ignition coil in a manner that corresponds to at least one of a plurality of the measured factors; and calculating a dwell time at which the necessary ignition voltage is output by the ignition coil.

An air conditioning unit capable of performing a refrigeration cycle using a small-GWP refrigerant is provided. A refrigeration cycle apparatus (1, 1a to 1m) includes a refrigerant circuit (10) including a compressor (21), a condenser (23, 31, 36), a decompressing section (24, 44, 45, 33, 38), and an evaporator (31, 36, 23), and a refrigerant containing at least 1,2-difluoroethylene enclosed in the refrigerant circuit (10).

A refrigeration cycle apparatus includes a primary-side refrigerant circuit in which a first refrigerant circulates and a secondary-side refrigerant circuit in which a second refrigerant circulates. The primary-side refrigerant circuit includes a primary-side compressor, a primary-side flow path of a cascade heat exchanger, a primary-side heat exchanger, and a primary-side switching mechanism. The secondary-side refrigerant circuit includes a secondary-side compressor, a secondary-side flow path of the cascade heat exchanger, a secondary-side switching mechanism, a suction flow path, a plurality of utilization-side heat exchangers, a first connection flow path, connecting the plurality of utilization-side heat exchangers and the secondary-side switching mechanism, including a secondary-side first connection pipe, a first heat source pipe, first branch pipes, junction pipes, first connection pipes, and first utilization pipes, a second connection flow path, connecting the plurality of utilization-side heat exchangers and the suction flow path, including a secondary side second connection pipe, a second heat source pipe, second branch pipes, the junction pipes, the first connection pipes, and the first utilization pipes, a third connection flow path, connecting the plurality of utilization-side heat exchangers and the secondary-side flow path of the cascade heat exchanger, including a secondary-side third connection pipe, a fourth heat source pipe, a fifth heat source pipe, third branch pipes, second connection pipes, and second utilization pipes.

An air-conditioning apparatus includes a four-way valve, a first three-way valve and a second three-way valve each having a closed port, a compressor, an indoor heat exchanger, an expansion valve, a first outdoor heat exchanger, a second outdoor heat exchanger, a bypass expansion valve, a check valve, a discharge temperature sensor, an indoor pipe temperature sensor, an indoor temperature sensor, a current sensor, and a controller configured to detect switching failure at the four-way valve, the first three-way valve, and the second three-way valve. The controller is configured to detect switching failure at the four-way valve, the first three-way valve, or the second three-way valve by using the temperatures measured by the discharge temperature sensor, the indoor pipe temperature sensor, and the indoor temperature sensor and the current in consideration of an operation status.

Provided is an air conditioning apparatus that sufficiently raises the temperature of hot air to be blown out when receiving a request for high-temperature air temporarily raising the temperature of the hot air. A first use side unit includes a first use side heat exchanger and a first use side fan. A second use side unit includes a second use side heat exchanger and a second use side fan. When the first use side unit receives a request for the high-temperature air and the second use side unit receives no request for the high-temperature air, the air conditioning apparatus shifts to a mode that performs control to reduce the airflow volume of the second use side fan or make the airflow volume of the second use side fan zero such as reducing the number of revolutions of the second use side fan in another room by 40 rpm.

Providing a refrigerant circuit apparatus evaluation system, which, when a plurality of refrigerant circuit apparatuses is installed, may accurately determine whether a heat source unit of each refrigerant circuit apparatus adversely affects the operation of a different refrigerant circuit apparatus. A refrigerant circuit apparatus evaluation system includes memory and processing circuitry. The processing circuitry acquires operation data on a first air-conditioning apparatus. The first air-conditioning apparatus includes a first heat source unit. The processing circuitry determines whether an operation of a second heat source unit different from the first heat source unit has an adverse effect on an operation of the first heat source unit based on the operation data on the first air-conditioning apparatus acquired by the processing circuitry when the first air-conditioning apparatus and a second air-conditioning apparatus including the second heat source unit are simultaneously operating.

An air conditioner and a method for controlling an air conditioner. The method may include detecting an outlet temperature of a compressor; detecting a change in temperature of a hot water supply pipe; determining a system error based on the outlet temperature of the compressor; and determining an abnormality in an adjustment valve based on the temperature of the hot water supply pipe when a system error is determined.

Methods and related systems for controlling superheat in a climate control system are disclosed. In an embodiment, the method includes (a) determining a superheat of a refrigerant downstream of a coil of a heat exchanger of the climate control system. In addition, the method includes (b) determining that an expansion valve upstream of the heat exchanger is fully open. Further, the method includes (c) adjusting a speed of air flowing across the coil or a speed of a compressor of the climate control system after (b) based on the determination in (a) to control the superheat of the refrigerant.

A refrigeration cycle apparatus includes an outdoor unit including a compressor, a first heat exchanger, and a first expansion valve, an indoor unit including a second expansion valve and a second heat exchanger, and a first pipe and a second pipe connected between the outdoor unit and the indoor unit. In a cooling operation, refrigerant delivered from the compressor sequentially passes through the first heat exchanger, the first expansion valve, the first pipe, the second expansion valve, the second heat exchanger, and the second pipe and returns to the compressor, and in the cooling operation, the first expansion valve converts refrigerant from a liquid-phase state to a two-phase state and sends two-phase refrigerant to the first pipe.

A flow path switching mechanism (70) includes first to fourth flow paths (71, 72, 73, 74) and opening and closing mechanisms (V1, V2, V3, V4, 75, 76) that can each open and close a corresponding one of the flow paths (71, 72, 73, 74). A first connection point (C1) connecting an inflow portion of the first flow path (71) and an inflow portion of the second flow path (72) is connected to a discharge portion of a compression unit (30). A second connection point (C2) connecting an outflow portion of the first flow path (71) and an inflow portion of the third flow path (73) is connected to a gas-side end of a heat source heat exchanger (22). A third connection point (C3) connecting an outflow portion of the second flow path (72) and an inflow portion of the fourth flow path (74) is connected to a gas-side end of a second utilization heat exchanger (85, 93). A fourth connection point (C4) connecting an outflow portion of the third flow path (73) and an outflow portion of the fourth flow path (74), and a gas-side end of a first utilization heat exchanger (83) are connected to a suction portion of the compression unit (30).