Abstract: In an air-conditioning system according to an aspect of the present disclosure, a gaseous refrigerant remaining in a reservoir can be discharged from the reservoir even when a cooling operation has started and the reservoir is being filled with a liquid refrigerant. Therefore, the reservoir can be filled with the liquid refrigerant at a faster speed.

Abstract: A cooling and heating control method of a multi type air conditioner in which a target pressure of a compressor is adjusted based on conditions of respective indoor units so as to reduce power consumption is provided. The cooling control method includes determining the indoor unit desired to execute power saving control, judging whether or not a difference between a temperature of a space in which the indoor unit desired to execute power saving control is located and a set temperature of the indoor unit is less than a reference value, raising a target evaporation temperature of the indoor unit upon judging that the difference is less than the reference value, comparing an evaporation temperature of the indoor unit with the raised target evaporation temperature, and raising an evaporation pressure of a compressor, when the evaporation temperature of the indoor unit is lower than the raised target evaporation temperature.

Abstract: An apparatus for detecting an oil level and a method for controlling the same, an apparatus for detecting oil flow and a method for controlling the same, and a method for controlling oil return using the detected oil level and the detected oil flow are disclosed. The level of oil stored in a compressor is measured at two or more positions. The frequency comparison scheme using two electrodes can correctly detect the level of oil stored in the compressor, a refrigerant state, and the level of mixed oils, and can determine an internal state of the compressor and a normal or abnormal state of the oil return system, such that the oil return control can be actively controlled. The flow of oil in the oil return pipe is detected so as to determine whether the oil is normally supplied in real time, such that a malfunction of the compressor is prevented and a valve state can be checked.

Abstract: 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.

Abstract: An air conditioner, having an outdoor unit and an indoor unit, to perform a heating operation and a defrosting operation, the air conditioner including a detection unit to detect a state of at least one selected between the outdoor unit and the indoor unit and to output the detected value, a controller to determine whether the air conditioner is in a stable state when the defrosting operation is completed and, upon determining that the air conditioner is in the stable state, to control the detected value output from the detection unit to determine entry time of the next defrosting operation, and a storage unit to store a value detected in the stable state. The entry time of the defrosting operation is accurately determined, thereby minimizing the number of times of the defrosting operation during the heating operation.

Abstract: A heat pump performs a simultaneous air-conditioning and heating operation through the addition of a flow path switching apparatus. The heat pump may include a plurality of outdoor units, a plurality of indoor units, and a plurality of flow path switching apparatuses that switch a flow path between an outdoor unit and an indoor unit. A refrigerant flow path may be formed from the outdoor unit to the indoor unit via a high-pressure gas pipe. The flow path switching apparatuses may switch a flow path so that a refrigerant flow path is formed from the indoor unit to the outdoor unit via a low-pressure gas pipe. The heat pump may further include an indoor unit mode controller that is connected to the plurality of outdoor units through a liquid pipe, and which is connected to each of the plurality of flow path switching apparatuses.