Daikin Industries, Ltd.

Yuusuke Oka

Takuro Yamada

Yuusuke Nakagawa

Masahiro Honda

Junya Minami

Ryuuta Ohura

Yasushi Hori

Yoshiyuki Tsuji

Hiroki Sasayama

Mariko Takakura

A refrigerant amount inference apparatus infers a refrigerant amount in an air conditioner in which a compressor, a heat source side heat exchanger, a supercooling heat exchanger, a pressure reducing valve, and a use side heat exchanger are connected to piping. The supercooling heat exchanger exchanges heat between refrigerant that passes through a valve provided in a bypass circuit and refrigerant in a mainstream circuit. The refrigerant amount inference apparatus includes an acquiring unit that acquires a state of refrigerant in first piping provided between the pressure reducing valve and the supercooling heat exchanger and an operation amount related to the state of the refrigerant in the first piping, and a training unit that performs training by associating the state of the refrigerant in the first piping and the operation amount related to the state of the refrigerant in the first piping with a refrigerant amount.

Apparatus, method, and program for estimating amount of refrigerant

A refrigeration apparatus includes: a heat source unit including a compressor for refrigerant and a heat-source-side heat exchanger; utilization units, each of which is connected in parallel to the heat source unit and includes a utilization-side heat exchanger; a refrigerant-flow-path switching unit that includes first gas-side control valves, each of which switches a flow of refrigerant in a corresponding one of the utilization units, and individually switches a flow of refrigerant in each of the utilization units; a first gas-side connection pipe disposed between the heat source unit and each of the first gas-side control valves and through which high-pressure gas refrigerant flows; first gas-side branch pipes, each of which is included in the first gas-side connection pipe and communicates with a corresponding one of the utilization units; and a blocking valve.

Refrigeration apparatus with multiple utilization units and refrigerant flow control

An air conditioning system includes: outdoor and indoor heat exchangers; first, second, and third control valves, which block refrigerant flow when fully closed; and a pressure adjuster. The first and second control valves are disposed in a gas-side refrigerant flow path (GL) between the outdoor and indoor heat exchangers. The third control valve is disposed in a liquid-side refrigerant flow path (LL) between the outdoor and indoor heat exchangers. The pressure adjuster adjusts the pressure of refrigerant in an indoor-side refrigerant flow path (IL) between the first control valve and the second control valve or the third control valve and the indoor heat exchanger. The pressure adjuster includes a pressure adjusting valve that bypasses refrigerant in the indoor-side refrigerant flow path (IL) to an outdoor-side refrigerant flow path (OL) between the first control valve and the second control valve or the third control valve and the outdoor heat exchanger.

Refrigeration apparatus

In a refrigeration apparatus including a refrigerant circuit in which a refrigerant in a gas-liquid two-phase state flows through a liquid-side connection pipe, a refrigerant-amount determining method and a refrigerant-amount determining device capable of grasping an appropriate refrigerant charging amount corresponding to the length of the connection pipe is provided. Provided is a refrigerant-amount determining method for a refrigerant to be charged to a refrigeration apparatus including a refrigerant circuit in which a compressor, an outdoor heat exchanger that functions as a condenser, an outdoor expansion valve, indoor heat exchangers that function as evaporators, a liquid-side connection pipe that feeds the refrigerant, which has passed through the outdoor heat exchanger and then has been decompressed by the outdoor expansion valve, to each of the indoor heat exchangers, and a gas-side connection pipe that feeds the refrigerant, which has passed through each of the indoor heat exchangers, to a suction side of the compressor, are connected to one another. The method determines a refrigerant amount of the refrigerant to be charged to the refrigerant circuit such that a refrigerant amount per unit length of the liquid-side connection pipe increases as a length of the liquid-side connection pipe is larger.

Refrigerant-amount determining method and refrigerant-amount determining device

An air conditioner, in which a liquid-pressure adjustment expansion valve that decompresses a refrigerant so that the refrigerant flowing through a liquid-refrigerant connection pipe is in a gas-liquid two-phase state is provided in an outdoor liquid-refrigerant pipe that connects a liquid-side end of an outdoor heat exchanger to the liquid-refrigerant connection pipe, properly transports the refrigerant in a two-phase state while suppressing an increase in a discharge temperature of a compressor. A liquid injection pipe that branches part of a refrigerant flowing through an outdoor liquid-refrigerant pipe and feeds the branched refrigerant to a compressor is connected to a portion of the outdoor liquid-refrigerant pipe on a side of an outdoor heat exchanger with respect to a liquid-pressure adjustment expansion valve.

Air conditioner

Noise that is generated from an indoor unit is suppressed when performing two-phase transport of refrigerant by using a liquid-pressure-adjusting expansion valve in an air conditioner including an outdoor unit, a plurality of indoor units each including an indoor heat exchanger, a relay unit that switches the plurality of indoor heat exchangers so that the indoor heat exchangers individually function as an evaporator or radiator for refrigerant, and a liquid-refrigerant connection pipe and a gas-refrigerant connection pipe that connect the outdoor unit and the indoor unit via the relay unit. The relay unit includes a relay expansion valve that further decompresses the refrigerant that has been decompressed by the liquid-pressure-adjusting expansion valve.

An air conditioner includes: liquid-side indoor expansion valves corresponding to a liquid side of respective indoor heat exchangers; and gas-side indoor expansion valves corresponding to a gas side of the respective indoor heat exchangers. In a case where both a heating-operation indoor heat exchanger and a heating-stopped indoor heat exchanger are present, the controller of the air conditioner controls the liquid-side indoor expansion valve and the gas-side indoor expansion valve corresponding to the heating-stopped indoor heat exchanger such that an opening degree of the gas-side indoor expansion valve becomes smaller than an opening degree of the liquid-side indoor expansion valve.

When refrigerant leakage occurs, a controller in an air conditioner performs first shutoff control to open a liquid relay shutoff valve and close an indoor expansion valve and a gas relay shutoff valve on the basis of information from a refrigerant leakage detector.

Air conditioner with refrigerant leakage control

To reduce noise coming from an indoor unit in an air conditioning apparatus that has an outdoor unit that has a compressor and an outdoor heat exchanger, the indoor unit that has an indoor heat exchanger, and a liquid refrigerant connection pipe and a gas refrigerant connection pipe that interconnect both units and in which a liquid pressure adjusting expansion valve that reduces a pressure of a refrigerant flowing through the liquid refrigerant connection pipe in such a way that the refrigerant is in a gas-liquid two-phase state is provided in an outdoor liquid refrigerant pipe that interconnects the liquid-side end of the outdoor heat exchanger and the liquid refrigerant connection pipe. An external expansion valve unit having an external expansion valve that further reduces the pressure of the refrigerant whose pressure has been reduced in the liquid pressure adjusting expansion valve is provided in the outdoor liquid refrigerant pipe.

Air conditioning apparatus

In an air conditioning device () to which an outdoor unit () and indoor units () are connected, when a flow rate of a gaseous refrigerant in a gas main pipe () is lower than a lower limit flow rate in main pipe, an amount of refrigerating machine oil accumulated in the gas main pipe () is calculated. When gas branch pipes () include a gas branch pipe () having a flow rate lower than a lower limit flow rate in branch pipe even though the flow rate of the gaseous refrigerant in the gas main pipe () is higher than the lower limit flow rate in main pipe, an amount of the machine oil accumulated in the gas branch pipe () is calculated. When the amounts are integrated and the integrated value exceeds a set amount, oil collecting operation is performed.

Air conditioning device

A multi-type air conditioning device controls an evaporation temperature and a condensing temperature, depending on required capacity of an indoor unit. The air conditioning device compares a current evaporation temperature or condensing temperature with a reference value, of an evaporation temperature or an condensing temperature, corresponding to a lower limit flow rate, of a gaseous refrigerant, required for refrigerating machine oil not to accumulate in, but to flow through, the gas branch pipes, and calculates an amount of the refrigerating machine oil accumulated in a gas branch pipe which does not satisfy the lower limit flow rate. When the calculated amount exceeds a set amount, the air conditioning device performs oil collecting operation, and controls the oil collecting operation in view of a flow rate of a gaseous refrigerant in gas branch pipes.

A controller of an air conditioning apparatus performs a start/stop frequency-reducing rotation speed control in which the rotation speed of a compressor is controlled based on request values from indoor units requesting a decrease in air conditioning capacity, disregarding request values from indoor units requesting an increase in air conditioning capacity, when each indoor temperature at all indoor units performing air conditioning operation is within a scope of a prescribed threshold temperature range surrounding a target indoor temperature at each indoor unit performing air conditioning operation.

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Osaka, Japan

Yuusuke Oka