A relay unit includes: a heat medium heat exchanger; a casing; a first refrigerant pipe connection port connected to one of two refrigerant pipes through which refrigerant circulates between the heat medium heat exchanger and the heat source side unit; a second refrigerant pipe connection port connected to an other of the refrigerant pipes; a first heat medium pipe connection port connected to one of two heat medium pipes through which a heat medium circulates between the heat medium heat exchanger and the load side unit; and a second heat medium pipe connection port connected to an other of the heat medium pipes. The first refrigerant pipe connection port, the second refrigerant pipe connection port, the first heat medium pipe connection port, and the second heat medium pipe connection port are provided on a top surface of the casing and face in a direction opposite to a direction of gravity.

A refrigerant distributor includes an outer pipe, an inner pipe, and a structural part. The refrigerant outflow hole is provided such that an angle θ between a lower end of the inner pipe on a vertical line passing through a center of the inner pipe and a position of presence of the refrigerant outflow hole as seen from the center of the inner pipe falls within a range of 10 degrees≤θ≤80 degrees. The refrigerant outflow hole comprises a sole refrigerant outflow hole provided in a vertical cross-section of the inner pipe at a position where the refrigerant outflow hole is provided.

An air conditioner may include: an outdoor unit including a compressor and an outdoor heat exchanger; a first indoor unit including a first indoor heat exchanger; and a second indoor unit including a second indoor heat exchanger and an indoor expansion valve, wherein the outdoor unit includes: a first outdoor pipe, an outdoor expansion valve provided in the first outdoor pipe, the first outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to pass through the outdoor expansion valve and flow to the first indoor unit; and a second outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to bypass the outdoor expansion valve and flow to the second indoor unit.

An air-conditioning apparatus includes a selection unit and a determination unit, the selection unit selecting a reverse-defrosting operation mode or a heating-defrosting simultaneous operation mode, the reverse-defrosting operation mode being a mode in which all of parallel heat exchangers are defrosted by stopping a heating operation, the heating-defrosting simultaneous operation mode being a mode in which each parallel heat exchanger is sequentially defrosted while continuing a heating operation, the determination unit determining whether or not a defrosting operation is to be started, in which the determination unit is configured to start the defrosting operation in a state where the amount of frost deposited on the parallel heat exchangers is smaller in a case where the heating-defrosting simultaneous operation mode is selected than in a case where the reverse-defrosting operation is selected.

An air-conditioning apparatus includes a control unit performing liquid refrigerant equalization control for correcting an imbalance in liquid refrigerant amount between accumulators. The control unit includes a first liquid refrigerant equalization control unit controlling an output of a fan to perform the liquid refrigerant equalization control and a second liquid refrigerant equalization control unit controlling a frequency of a compressor to perform the liquid refrigerant equalization control. The second liquid refrigerant equalization control unit determines an increase or reduction in frequency of the compressor so that a total refrigerant circulation amount is not below a predetermined amount. When a value is within a predefined acceptable range, the control unit selects the first liquid refrigerant equalization control unit to perform the liquid refrigerant equalization control. When the value is outside the acceptable range, the control unit selects the second liquid refrigerant equalization control unit to perform the liquid refrigerant equalization control.

This air conditioner performs a cooling operation and a heating operation in parallel with each other with an outdoor unit and indoor units connected together through two communication pipes. The air conditioner includes a switching mechanism changing the directions of refrigerants flowing through the communication pipes depending on whether a heating dominant operation is being performed in a first load region where a cooling load is relatively light or a second load region where the cooling load is heavier than in the first load region. In the second load region, the switching mechanism allows a low-pressure refrigerant to flow from the indoor units to the outdoor unit through the second communication pipe thicker than the first communication pipe to reduce a performance deterioration due to the pressure loss involved with the heating dominant operation.

The heat source controller transmits the drive permission signal (SE) to the utilization controller when the compression element is drivable. The utilization controller opens a utilization expansion valve when heat exchange in a utilization heat exchanger is required, on condition that the utilization controller receive the drive permission signal (SE).

The present invention provides a vapor injection module including a first expansion means configured to block a flow of a condensed refrigerant or expand the condensed refrigerant and transmit the refrigerant to a gas-liquid separator in accordance with an air conditioning mode, the gas-liquid separator configured to receive the refrigerant from the first expansion means and separate the refrigerant into a gaseous refrigerant and a liquid refrigerant, and a second expansion means configured to allow the condensed refrigerant to pass therethrough, expand the condensed refrigerant, or expand the liquid refrigerant separated in the gas-liquid separator in accordance with the air conditioning mode.

The present invention relates to an air conditioner that adjusts room temperature to a set temperature, and the problem to be solved thereby is to reduce the frequency of occurrence of situations in which the room temperature does not approach the set temperature. In the air conditioner, a target suction pressure is set to a value obtained by subtracting, from an evaporation pressure of an indoor heat exchanger, a pressure loss estimation value from an inlet of the indoor heat exchanger to a suction port of a compressor so that an evaporation temperature of the indoor heat exchanger is maintained constant. The displacement of the compressor is controlled so that the suction pressure becomes equal to the target suction pressure. A deviation determination unit determines whether the room temperature is stabilized at a temperature deviated from the set temperature. When the deviation determination unit determines that the room temperature is deviated from the set temperature, a controller changes the pressure loss estimation value so that the room temperature approaches the set temperature.

The present disclosure provides an air conditioner. The air conditioner includes a compressor; a sensor for measuring the compressors state configured to detect compressor state information that includes at least one of a pressure value and a saturation temperature of the compressor; and a controller configured to control air flow on the side of an indoor unit by comparing the compressor state information measured from the sensor and a threshold.