Daikin Industries, Ltd.

Yuusuke Nakagawa

Takuro Yamada

Yuusuke Oka

Masahiro Honda

Makoto Kojima

Shigeki Kamitani

Mikio Kagawa

Tadashi Sao

Hiroki Sasayama

Katsutoshi Sakurai

An air conditioning system capable of reducing noise incidental to gas-liquid two-phase transfer is provided. The air conditioning system () performs a refrigeration cycle in a refrigerant circuit (RC) including an outdoor unit (), a plurality of indoor units (), and a liquid-side connection pipe (LC) connecting the outdoor unit () and the indoor units (). The air conditioning system () includes a second outdoor control valve (, electric valve) decompressing the refrigerant flowing in the refrigerant circuit (RC) in accordance with an opening degree, an operating-capacity variation detection portion (, detection portion) detecting change of the number of operating units in accordance with device information, and a device control portion (, control portion) controlling a state of the second outdoor control valve (). The device control portion () executes first control (feed-forward control) when the change of the number of operating units is detected by the operating-capacity variation detection portion (), and adjusts the opening degree of the second outdoor control valve () to suppress a rise of pressure of the refrigerant flowing into the operating unit.

Air conditioning system

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

A method for determining a pipe diameter of a liquid-side connection pipe in a refrigeration apparatus includes causing a computer to obtain a heating capacity, maximum heating load, and maximum cooling load; causing the computer to determine a pipe diameter of the liquid-side connection pipe by reducing a reference pipe diameter based on either a value obtained by dividing the maximum heating load by the maximum cooling load or a value obtained by subtracting the maximum heating load from the heating capacity; and installing the refrigeration apparatus using the liquid-side connection pipe having the determined pipe diameter.

Pipe diameter determination method, pipe diameter determination apparatus, and refrigerating apparatus

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

A casing of an outdoor unit includes support pillars, each of the support pillars having standing wall portions arranged along the up and down direction, and a top plate mounted on upper ends of the support pillars. Substantially horizontal abutment portions extending upward from at least a part of the standing wall portions and being brought into surface contact with a lower surface of the top plate in a state where the top plate is floated up from upper ends of the standing wall portions are provided in the upper end of each of the support pillars.

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Osaka, Japan

Yuusuke Nakagawa