Patent ID: 11906191
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Thermal processes and apparatus (Mechanical engineering)
Classification: CPC F  Y | IPC F

Claim 0:
1. An air-conditioning apparatus comprising:
a primary-side circuit in which a compressor that compresses refrigerant, a first flow switching device that switches a circulation path of the refrigerant, an outdoor heat exchanger that exchanges heat between the refrigerant and a heat-source-side fluid, a second flow switching device that switches the circulation path of the refrigerant, a first expansion device that is disposed at a pipe between the first flow switching device and the second flow switching device and adjusts a pressure of the refrigerant, and a relay heat exchanger that exchanges heat between the refrigerant and a heat medium different from the refrigerant are connected by pipes and in which the refrigerant circulates;
a secondary-side circuit in which the relay heat exchanger, a pump that pressurizes the heat medium, a plurality of indoor heat exchangers, each of which exchanges heat between the heat medium and air for an air-conditioning target space, and heat medium flow control devices, each of which is installed in such a manner as to correspond to an indoor heat exchanger among the indoor heat exchangers and adjusts a flow rate of the heat medium passing through the indoor heat exchanger, are connected by pipes and in which the heat medium circulates;
a refrigerant-refrigerant heat exchanger disposed at a pipe connecting the second flow switching device and the first expansion device to each other; and
a bypass circuit including a bypass pipe having an end connected to a pipe between the refrigerant-refrigerant heat exchanger and the first expansion device, and another end connected to a pipe between the second flow switching device and the compressor, and a bypass expansion device that adjusts an amount of refrigerant passing through the bypass pipe;
a controller configured to control the first flow switching device and the second flow switching device to provide the circulation path such that in a cooling operation and a heating operation, the refrigerant and the heat-source-side fluid flow through the outdoor heat exchanger in opposite directions and the refrigerant flows through the relay heat exchanger in a constant direction,
wherein the pump is installed such that the heat medium flows through the relay heat exchanger in a direction opposite to the direction in which the refrigerant flows, and
the refrigerant-refrigerant heat exchanger
is disposed such that
the refrigerant passing through the refrigerant-refrigerant heat exchanger and flowing between the second flow switching device and the first expansion device and
the refrigerant passing through the refrigerant-refrigerant heat exchanger and flowing through the bypass circuit
flow in opposite directions, and

exchanges, in the refrigerant-refrigerant heat exchanger, heat between
high-pressure two-phase refrigerant or liquid refrigerant flowing between the second flow switching device and the first expansion device and
low-pressure two-phase refrigerant flowing through the bypass circuit having the bypass pipe

in any of cooling and the heating operations.