An outdoor unit of an air-conditioning apparatus includes an outdoor unit main body, a compressor, an outdoor heat exchanger, an outdoor fan, an outdoor air temperature detection unit, and a control unit. The control unit stores an outdoor air temperature that is detected when the outdoor unit main body receives an operation stop signal, a temperature determination unit configured to determine whether the outdoor air temperature stored in the storage unit is less than a temperature threshold value when the outdoor unit main body receives an operation start signal, and an operation timing setting unit configured to select an operation mode of the compressor based on an outdoor air temperature detected by the outdoor air temperature detection unit after operation of the outdoor fan is resumed in a case where the temperature determination unit determines that the outdoor air temperature is less than the temperature threshold value.

A system based on temperature and/or pressure switches connected to a fan controller. An HVAC circuit includes at least one condenser coil with a plurality of tubes, one or more stages coupled to one or more compressors, at least one temperature sensor, at least one fan configured to provide airflow across the plurality of tubes, and a controller. Instead of cycling the fan off and on, fans associated with the condenser are kept running at a low speed.

A system includes a compressor, an indoor fan, a thermostat, an indoor fan controller, and a compressor controller. The thermostat provides first and second signals based on indoor loading. The fan controller operates the fan in low speed mode and the compressor controller operates the compressor in low capacity mode when only the first signal is asserted. The compressor controller automatically switches the compressor to high capacity mode if only the first signal remains asserted past the low capacity mode runtime. The fan controller operates the fan in high speed mode when the second signal is asserted while the first signal is still asserted. The compressor controller continues to operate the compressor in high capacity mode and the fan controller operates the fan in low speed mode after the second signal is de-asserted, until the first signal is de-asserted, at which point the fan and compressor are turned off.

A refrigeration cycle apparatus includes at least a compressor, a condenser, an internal heat exchanger configured to exchange heat between parts of refrigerant each having a different pressure, a refrigerant reservoir configured to store the refrigerant, a first pressure reducing device, an evaporator. The compressor, the condenser, the internal heat exchanger, the refrigerant reservoir, the first pressure reducing device, and the evaporator are sequentially connected to each other. The refrigeration cycle apparatus also includes a first pipe connecting the condenser and the refrigerant reservoir, and a second pressure reducing device provided to the first pipe between the internal heat exchanger and the refrigerant reservoir.

A sound level control system for a heating, ventilation, and air conditioning (HVAC) system is provided. The sound level control system comprises an outdoor unit with a compressor, an outdoor fan, and an outdoor controller and a communication device located at a predefined distance from the outdoor unit. The communication device measures sound levels in response to operating the outdoor unit. The outdoor controller is configured to receive a first noise level limit for a predefined time period, receive an instruction related to selective control of the outdoor unit, selectively control both of the compressor to rotate at a first compressor speed and the outdoor fan to rotate at a first fan speed based on the noise level limit for the predefined time period, and receive information related to whether a sound pressure level at a predefined location exceeds the first noise level limit for the predefined time period.

A transportation container includes a storage volume. A refrigeration system is contained within the storage volume. The refrigeration system includes a fan configured to ingest exterior air, a condenser coil immediately downstream of the fan, and a vent configured exhaust spent cooling air from the storage volume. A controller is configured to control the refrigeration system. the controller includes instructions configured to cause the refrigeration system to detect an indication of operational deterioration of a transportation container refrigeration system, reverse a rotational direction of an airflow fan such that air is drawn over a refrigeration coil and expelled from the transportation container using the airflow fan, and revert the rotational direction of the airflow fan at a conclusion of a cleaning operation.

When a controller performs a defrosting operation in which frost on an outdoor heat exchanger is caused to be melted, the controller is configured to perform a first defrosting control in which a switching state of a switching device is set to a first state, after the controller performs the first defrosting control, perform a second defrosting control in which the switching state of the switching device is set to a second state, and after the controller performs the second defrosting control, perform a third defrosting control in which the switching state of the switching device is set to the first state.

An air-conditioning apparatus including heat source apparatuses each including a compressor and an accumulator includes: a refrigerant amount calculation unit that calculates an amount of the refrigerant accumulated in the accumulator in one of the heat source apparatuses that is to be controlled; a refrigerant differential amount calculation unit configured to calculate, when the number of the heat source apparatuses is two, a differential amount between the calculated amount and an amount of the refrigerant in the accumulator in the other heat source apparatus, and calculate, when the number of the heat source apparatuses is three or more, a differential amount between the calculated amount of the refrigerant and an average amount of amounts of the refrigerant accumulated in the accumulators in the heat source apparatuses; and a liquid equalization control unit that controls the heat source apparatus to be controlled, based on the calculated differential amount.

A heat exchanger connected to a refrigerant pipe includes: heat transfer tubes; and a header that connects the refrigerant pipe and the heat transfer tubes, and that forms a refrigerant flow path between the refrigerant pipe and the heat transfer tubes. The header includes a first member that includes a first plate-shaped portion, and a second member that includes a second plate-shaped portion that is stacked on a heat transfer tubes side of the first plate-shaped portion. The first plate-shaped portion has a first opening that forms the refrigerant flow path. The second plate-shaped portion has a second opening that forms the refrigerant flow path. When viewed in a stacking direction of the first plate-shaped portion and the second plate-shaped portion, the second opening and the first opening overlap each other at a first region and at a second region that is different from the first region.

Provided is an air-conditioning apparatus having a low-outside-air-temperature cooling operation mode including: a refrigerant circuit; an outdoor fan; an outdoor air temperature sensor; an indoor heat exchanger intermediate temperature sensor; an indoor heat exchanger outlet temperature sensor; and a controller configured to, when a measured value from the outdoor air temperature sensor is equal to or less than a predetermined value, perform the low-outside-air-temperature cooling operation mode, wherein in the low-outside-air-temperature cooling operation mode, the controller is configured to reduce a rotation speed of the outdoor fan, and to, when a difference between a measured value from the indoor heat exchanger outlet temperature sensor and a measured value from the indoor heat exchanger intermediate temperature sensor is equal to or greater than a first threshold, increase an opening degree of the pressure reducing device.