Daikin Industries, Ltd.

Takeshi Hikawa

Shinichi Kasahara

Manabu Yoshimi

Toshiyuki Maeda

Satoshi Ishikawa

Shohei Yamada

Takahiro Yamaguchi

Shuji Fujimoto

Yasuto Yanagida

Masanobu Kita

Sumikazu Matsuno

Shizuka Sadai

Akihiro Inao

Shigenobu Izumi

Kiyoshi Koizumi

Hiroyuki Kagitani

Hidetaka Kishimoto

An air conditioning apparatus includes a refrigerant circuit in which a plurality of indoor units respectively including an indoor heat exchanger and an indoor expansion valve are connected to an outdoor unit including an outdoor expansion valve via a liquid-refrigerant connection pipe. The air conditioning apparatus individually controls each of the indoor units to operate or stop. The air conditioning apparatus includes a controller. When at least one of the indoor heat exchangers functions as a radiator, the controller controls an opening degree of the indoor expansion valve and an opening degree of the outdoor expansion valve. The apparatus—determines whether a refrigerant amount in the refrigerant circuit is appropriate on the basis of an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve and the outdoor expansion valve.

Air conditioning apparatus, management device, and connection pipe

A refrigerant amount determining device includes: an operation data acquiring unit configured to acquire operation data of an air conditioning system; a calculating unit configured to calculate a refrigerant amount index value from the operation data acquired; an inferring unit configured to infer information regarding correction of the refrigerant amount index value using a correction model and at least one of the acquired operation data or the calculated refrigerant amount index value; and a determining unit configured to determine a refrigerant amount of the air conditioning system based on the information regarding correction of the refrigerant amount index value.

Apparatus, method, and program for estimating amount of refrigerant

A performance degradation diagnosis system includes a determining unit, and control unit. A refrigeration cycle apparatus includes a refrigerant circuit having a compressor, heat-source-side heat exchanger, and use-side heat exchanger. The determining unit determines, based on an index indicating an operation state of the refrigeration cycle apparatus, performance degradation of the refrigeration cycle apparatus with respect to each of a plurality of performance degradation factors. In a case in which the determining unit determines performance degradation, the control unit grasps an operation condition of the refrigeration cycle apparatus which is operating. In a case in which the operation condition of the refrigeration cycle apparatus is not suitable to determine performance degradation with respect to a performance degradation factor of a determination target, the control unit controls the operation condition of the refrigeration cycle apparatus so that the operation condition of the refrigeration cycle apparatus becomes an appropriate operation condition.

Performance degradation diagnosis system for refrigeration cycle apparatus

A refrigerant leakage determination system capable of detecting leakage of refrigerant without requiring complicated processing is provided. A refrigerant leakage determination system is a refrigerant leakage determination system of a refrigeration cycle apparatus that includes a refrigerant circuit including a heat-source-side heat exchanger and has, as operating modes, a normal mode in which the heat-source-side heat exchanger is caused to function as an evaporator and a defrosting mode in which the heat-source-side heat exchanger frosted during a normal operation is defrosted. The refrigerant leakage determination system includes a processor configured to acquire defrosting information regarding a relationship between a normal operation period and the number of defrosting operations, and memory that stores the defrosting information. The processor is further configured to determine, based on the acquired defrosting information, leakage of refrigerant in the refrigerant circuit.

Refrigerant leakage determination system and refrigeration cycle apparatus

To reduce a leakage current when a motor for driving a compressor is energized, with the compressor unoperated. Setting the carrier frequency of an inverter at a value lower than that used during normal operation to cause phase interruption electrification of the motor.

Method of preheating inverter-driven compressor and device therefor

An instantaneous current and instantaneous voltage of a three-phase coil of a brushless DC motor are detected, and the internal condition of a compressor is predicted from these detection values. The prediction about the internal condition of the compressor is made in such a way that motor driving torque which is a parameter of a motor model is identified and poor lubrication, liquid compression or the like is predicted from this identified motor driving torque. This enables it to make, in real time, a failure forecast, failure diagnosis etc. on the compressor.

Drive unit for compressor and refrigerator

Resistance of the coil of a DC motor is calculated by using the motor current and the motor voltage, and the coil temperature is estimated by using the resistance-temperature characteristics of the coil.

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Osaka, Japan

Takeshi Hikawa