US 2017/0370627 A1Published application

Refrigeration cycle apparatus

AssigneeMitsubishi Electric Corporation

InventorsNaofumi TAKENAKA, Shinichi WAKAMOTO, Kazuya WATANABE, Naomichi TAMURA, Tadashi ARIYAMA, Koji YAMASHITA, Takeshi HATOMURA

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Abstract

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.

Claims21

Dependent claims

A refrigeration cycle apparatus comprising:

a main circuit including a compressor, a flow switching device configured to switch a passage of refrigerant discharged from the compressor, a first heat exchanger configured to serve at least as a condenser, a flow rate adjusting device provided for the first heat exchanger, and a plurality of parallel heat exchangers provided in parallel with each other and each being a second heat exchanger configured to serve at least as an evaporator;
a defrosting circuit configured to branch part of the refrigerant discharged from the compressor and allow the branched refrigerant to flow into selected one or more of the plurality of parallel heat exchangers;
a detector configured to detect, as an index for determining an amount of frost deposited on the parallel heat exchangers, an operation time period of the main circuit during which all of the parallel heat exchangers serve as evaporators;
and
a controller configured to control the flow switching device and the defrosting circuit,
the controller including
a selection unit configured to select one of a reverse-defrosting operation mode and a heating-defrosting simultaneous operation mode as a mode for performing a defrosting operation for defrosting the parallel heat exchangers,
the reverse-defrosting operation mode being an operation mode in which the flow switching device is switched to connect the passage of the refrigerant discharged from the compressor to the second heat exchanger to defrost all of the parallel heat exchangers,
the heating-defrosting simultaneous operation mode being an operation mode in which the refrigerant discharged from the compressor is allowed to flow into one or more of the parallel heat exchangers by the defrosting circuit, the one or more of the parallel heat exchangers serve as heat exchangers that are defrosting targets, and one or more of the parallel heat exchangers other than the heat exchangers that are defrosting targets serve as evaporators, and
a determination unit configured to determine whether or not the defrosting operation is to be started based on a result of detection performed by the detector,
the determination unit being configured to start the defrosting operation in a case where the operation time period detected by the detector is longer than an operation time period threshold, the operation time period threshold being a smaller value in a case where the heating-defrosting simultaneous operation mode is selected than in a case where the reverse-defrosting operation mode is selected.

8 more elements

A refrigeration cycle apparatus comprising:

a main circuit including a compressor, a flow switching device configured to switch a passage of refrigerant discharged from the compressor, a first heat exchanger configured to serve at least as a condenser, a flow rate adjusting device provided for the first heat exchanger, and a plurality of parallel heat exchangers provided in parallel with each other and each being a second heat exchanger configured to serve at least as an evaporator;
a defrosting circuit configured to branch part of the refrigerant discharged from the compressor and allow the branched refrigerant to flow into selected one or more of the plurality of parallel heat exchangers;
a detector configured to detect, as an index for determining the amount of frost deposited on the parallel heat exchangers, an operation time period of the main circuit in which all of the parallel heat exchangers serve as evaporators, and
a controller configured to control the flow switching device and the defrosting circuit,
the controller including
a selection unit configured to select one of a reverse-defrosting operation mode and a heating-defrosting simultaneous operation mode as a mode for performing a defrosting operation for defrosting the parallel heat exchangers,
the reverse-defrosting operation mode being an operation mode in which the flow switching device is switched to connect the passage of the refrigerant discharged from the compressor to the second heat exchanger to defrost all of the parallel heat exchangers,
the heating-defrosting simultaneous operation mode being an operation mode in which the refrigerant discharged from the compressor is allowed to flow into one or more of the parallel heat exchangers by the defrosting circuit, the one or more of the parallel heat exchangers serve as heat exchangers that are defrosting targets, and one or more of the parallel heat exchangers other than the heat exchangers that are defrosting targets serve as evaporators, and
a determination unit configured to determine whether or not the defrosting operation is to be started based on a result of detection performed by the detector, wherein
where a product of a heat transfer area and a heat transfer rate of a heat exchanger is defined as an AK value and where a ratio of the AK value of a heat exchanger that is the defrosting target to the AK values of all of the parallel heat exchangers is defined as A %,
the determination unit is configured to
start the defrosting operation in a case where the reverse-defrosting operation mode is selected and if the operation time period becomes longer than an operation time period threshold, and
start the defrosting operation in a case where the heating-defrosting simultaneous operation mode is selected and if a value of the following formula becomes larger than the operation time period threshold:
(the operation time period+a time period of precedent defrosting operation in the heating-defrosting simultaneous operation mode)×100/(100−A).

11 more elements

A refrigeration cycle apparatus comprising:

a main circuit including a compressor, a flow switching device configured to switch a passage of refrigerant discharged from the compressor, a first heat exchanger configured to serve at least as a condenser, a flow rate adjusting device provided for the first heat exchanger, and a plurality of parallel heat exchangers provided in parallel with each other and each being configured to serve as a second heat exchanger that serves at least as an evaporator;
a defrosting circuit configured to branch part of the refrigerant discharged from the compressor to be branched and allow the branched refrigerant to flow into selected one or more of the plurality of parallel heat exchangers;
a detector configured to detect, as an index for determining an amount of frost deposited on the parallel heat exchangers, a pressure of the refrigerant flowing in at least one of the parallel heat exchangers serving as evaporators;
and
a controller configured to control the flow switching device and the defrosting circuit,
the controller including
a selection unit configured to select one of a reverse-defrosting operation mode and a heating-defrosting simultaneous operation mode as a mode for performing a defrosting operation for defrosting the parallel heat exchangers,
the reverse-defrosting operation mode being an operation mode in which the flow switching device is switched to connect the passage of the refrigerant discharged from the compressor to the second heat exchanger to defrost all of the parallel heat exchangers,
the heating-defrosting simultaneous operation mode being an operation mode in which the refrigerant discharged from the compressor is allowed to flow into one or more of the parallel heat exchangers by the defrosting circuit, the one or more of the parallel heat exchangers serve as heat exchangers that are defrosting targets, and one or more of the parallel heat exchangers other than the heat exchangers that are defrosting targets serve as evaporators, and
a determination unit configured to determine whether or not the defrosting operation is to be started based on a result of detection performed by the detector,
the determination unit being configured to start the defrosting operation in a case where the operation time period detected by the detector is longer than an operation time period threshold, the operation time period threshold being a smaller value in a case where the heating-defrosting simultaneous operation mode is selected than in a case where the reverse-defrosting operation mode is selected.

8 more elements

A refrigeration cycle apparatus comprising:

a main circuit including a compressor, a flow switching device configured to switch a passage of refrigerant discharged from the compressor, a first heat exchanger configured to serve at least as a condenser, a flow rate adjusting device provided for the first heat exchanger, and a plurality of parallel heat exchangers provided in parallel with each other and each being configured to serve as a second heat exchanger that serves at least as an evaporator;
a defrosting circuit configured to branch part of the refrigerant discharged from the compressor and allow the branched refrigerant to flow into selected one or more of the plurality of parallel heat exchangers;
a detector configured to detect, as an index for determining an amount of frost deposited on the parallel heat exchangers, a temperature of the refrigerant flowing in at least one of the parallel heat exchangers serving as evaporators;
and
a controller configured to control the flow switching device and the defrosting circuit,
the controller including
a selection unit configured to select one of a reverse-defrosting operation mode and a heating-defrosting simultaneous operation mode as a mode for performing a defrosting operation for defrosting the parallel heat exchangers,
the reverse-defrosting operation mode being an operation mode in which the flow switching device is switched to connect the passage of the refrigerant discharged from the compressor to the second heat exchanger to defrost all of the parallel heat exchangers,
the heating-defrosting simultaneous operation mode being an operation mode in which the refrigerant discharged from the compressor is allowed to flow into one or more of the parallel heat exchangers by the defrosting circuit, the one or more of the parallel heat exchangers serve as heat exchangers that are defrosting targets, and one or more of the parallel heat exchangers other than the heat exchangers that are defrosting targets serve as evaporators, and
a determination unit configured to determine whether or not the defrosting operation is to be started based on a result of detection performed by the detector,
the determination unit being configured to
start the defrosting operation in a case where the temperature detected by the detector is lower than a temperature threshold,
the temperature threshold being a larger value in a case where the heating-defrosting simultaneous operation mode is selected than in a case where the reverse-defrosting operation mode is selected

10 more elements

Dependencies are inferred from the claim text.