CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims priority benefit of Korean Application No. 10-2019-0009711 filed on Jan. 25, 2019, whose entire disclosure is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to an air conditioner, and more particularly, to an air conditioner operated in such a manner that when some of a plurality of indoor heat exchangers installed in a low temperature warehouse perform a defrosting operation, the other indoor heat exchangers perform a refrigeration operation.

2. Description of the Related Art

A refrigeration cycle generally means a cycle of supplying heat to a place that needs heat or absorbing heat by using a circulation cycle of a refrigerant. A compressor, a condenser, an expansion valve, and an evaporator are used to implement such a refrigeration cycle.

An apparatus or system for heating or cooling indoor air using such a refrigeration cycle is called an air conditioner. The air conditioner may cool or heat the indoor air by providing the heat of the refrigerant to the indoor air or by taking the heat of the indoor air into the refrigerant.

An evaporator of an air conditioner may be installed in a warehouse, a refrigerant may absorb the heat in the warehouse to provide a low temperature warehouse, and a plurality of the evaporators may be installed in the low temperature warehouse.

Frost may be formed in the evaporator installed in the low temperature warehouse (the indoor), which degrades the heat exchange performance.

Accordingly, an air conditioner in which a heater is provided in the evaporator in order to remove frost formed in the evaporator or hot gas discharged from the compressor is introduced to perform a defrosting operation has been launched.

However, such a conventional air conditioner has a problem in that a temperature is increased in a low temperature warehouse (indoor) due to a heater, or a plurality of heat exchangers installed in the low temperature warehouse perform defrosting operation simultaneously to increase the temperature of the low temperature warehouse.

In addition, in the case of the air conditioner in which a plurality of heat exchangers are provided in the low temperature warehouse and hot gas discharged from the compressor is introduced into the plurality of heat exchangers provided in the low temperature warehouse, three or more connection pipes between an indoor unit and an outdoor unit are required. Accordingly, there is a problem in that the cost is increased.

SUMMARY OF THE INVENTION

The present disclosure has been made in view of the above problems, and provides an air conditioner in which hot gas discharged from a compressor is introduced into some of a plurality of indoor heat exchangers to perform a defrosting operation, and the other indoor heat exchangers perform a refrigeration operation.

The present disclosure further provides an air conditioner that connects an outdoor unit and an indoor unit with two pipes, while some of a plurality of indoor heat exchangers perform a defrosting operation and the other indoor heat exchangers perform a refrigeration operation.

In accordance with an aspect of the present disclosure, an air conditioner includes: an outdoor unit including a compressor for compressing a refrigerant, and an outdoor heat exchanger for heat-exchanging outdoor air with the refrigerant; an indoor unit including a plurality of indoor heat exchangers for heat-exchanging indoor air with the refrigerant, and an indoor expansion valve which is connected to the plurality of indoor heat exchangers and expands the refrigerant; and a continuous refrigeration apparatus including a first gas control unit connected to a first indoor heat exchanger of the plurality of indoor heat exchangers, a second gas control unit connected to a second indoor heat exchanger of the plurality of indoor heat exchangers, a first pipe connecting a liquid pipe of the outdoor unit and a liquid of the indoor unit, and a second pipe which is branched from the first pipe and connected to the first gas control unit and the second gas control unit.

The first gas control unit includes: a first-first flow path connecting the first gas control unit to the second pipe; a first-second flow path which is connected to the first-first flow path, and through which the refrigerant discharged from the first indoor heat exchanger flows during a refrigeration operation of the first indoor heat exchanger; and a first-third flow path which is connected in parallel with the first-second flow path, and guides the refrigerant discharged from the compressor to the first indoor heat exchanger during a defrosting operation of the first indoor heat exchanger, and connects a gas pipe of the outdoor unit and the first indoor heat exchanger.

The second gas control unit includes: a second-first flow path connecting the second gas control unit to the second pipe; a second-second flow path which is connected to the second-first flow path, and through which the refrigerant discharged from the second indoor heat exchanger flows during a refrigeration operation of the second indoor heat exchanger; and a second-third flow path which is connected in parallel with the second-second flow path, and guides the refrigerant discharged from the compressor to the second indoor heat exchanger during a defrosting operation of the second indoor heat exchanger, and connects the gas pipe of the outdoor unit and the second indoor heat exchanger.

The outdoor unit includes a four-way valve for guiding the refrigerant discharged from the compressor to the outdoor heat exchanger or the indoor heat exchanger selectively.

The four-way valve guides the refrigerant discharged from the compressor to the outdoor heat exchanger, in the refrigeration operation of all the plurality of indoor heat exchangers, and guides the refrigerant discharged from the compressor to the gas pipe of the outdoor unit, in the defrosting operation of at least one of the plurality of indoor heat exchangers.

The continuous refrigeration apparatus includes a plurality of gas control units including the first gas control unit and the second gas control unit.

The plurality of gas control units are provided in the same number of the plurality of indoor heat exchangers.

The first pipe has one end connected to the liquid pipe of the outdoor unit, and the other end connected to the liquid pipe of the indoor unit, one end of the first gas control unit and one end of the second gas control unit are converged to be connected to the gas pipe of the outdoor unit, the other end of the first gas control unit is connected to the first indoor heat exchanger, and the other end of the second gas control unit is connected to the second indoor heat exchanger.

The first gas control unit includes: a first-first solenoid valve which is installed in the first-first flow path, and controls a flow of the refrigerant flowing through the first-first flow path; and a first-second solenoid valve which is installed in the first-third flow path, and controls a flow of the refrigerant flowing through the first-third flow path.

The second gas control unit includes: a second-first solenoid valve which is installed in the second-first flow path, and controls a flow of the refrigerant flowing through the second-first flow path; and a second-second solenoid valve which is installed in the second-third flow path, and controls a flow of the refrigerant flowing through the second-third flow path.

The first-first solenoid valve is opened during the refrigeration operation of the first indoor heat exchanger, and is closed during the defrosting operation of the first indoor heat exchanger.

The first-second solenoid valve is opened during the defrosting operation of the first indoor heat exchanger, and is closed during the refrigeration operation of the first indoor heat exchanger and the defrosting operation of the second indoor heat exchanger.

The second-first solenoid valve is opened during the refrigeration operation of the second indoor heat exchanger, and is closed during the defrosting operation of the second indoor heat exchanger.

The second-second solenoid valve is opened during the defrosting operation of the second indoor heat exchanger, and is closed during the defrosting operation of the first indoor heat exchanger and the refrigeration operation of the second indoor heat exchanger.

The first gas control unit includes a first-first check valve which is installed in the first-second flow path, and blocks a flow, toward the first-first flow path and the first-second flow path, of the refrigerant introduced into the first gas control unit from the gas pipe of the outdoor unit, and guides the refrigerant toward the first-third flow path.

The second gas control unit includes a second-first check valve which is installed in the second-second flow path, and blocks a flow, toward the second-first flow path and the second-second flow path, of the refrigerant introduced into the second gas control unit from the gas pipe of the outdoor unit, and guides the refrigerant toward the second-third flow path.

The first gas control unit includes a first-second check valve which is installed in the first-third flow path, and blocks a flow of the refrigerant, which is introduced into the first gas control unit from the first indoor heat exchanger, flowing through the first-third flow path, and guides the refrigerant toward the first-second flow path.

The second gas control unit includes a second-second check valve which is installed in the second-third flow path, and blocks a flow of the refrigerant, which is introduced into the second gas control unit from the second indoor heat exchanger, flowing through the second-third flow path, and guides the refrigerant toward the second-second flow path.

The continuous refrigeration apparatus includes: a defrost expansion valve installed in the first pipe; a first pipe check valve which is disposed in parallel with the defrost expansion valve and blocks a refrigerant flow flowing from the indoor unit to the outdoor unit; and a second pipe check valve which is installed in the second pipe and blocks a flow of the refrigerant flowing from the first pipe to the second pipe.

The indoor expansion valve includes: a first indoor expansion valve which is installed in a flow path connecting the first indoor heat exchanger and the liquid pipe of the indoor unit; and a second indoor expansion valve which is installed in a flow path connecting the second indoor heat exchanger and the liquid pipe of the indoor unit.

In accordance with another aspect of the present disclosure, an air conditioner includes: an outdoor unit including a compressor for compressing a refrigerant, an outdoor heat exchanger for heat-exchanging outdoor air with the refrigerant, an outdoor unit gas pipe connected to the compressor, and an outdoor unit liquid pipe connected to the outdoor heat exchanger; an indoor unit including a plurality of indoor heat exchangers for heat-exchanging indoor air with the refrigerant, a plurality of indoor unit gas pipes connected to one end of the plurality of indoor heat exchangers respectively, an indoor unit liquid pipe connected to the other end of the plurality of indoor heat exchangers, and a plurality of indoor expansion valves installed in a flow path connecting the indoor unit liquid pipe and the plurality of indoor heat exchangers respectively; and a continuous refrigeration apparatus which is disposed between the outdoor unit and the indoor unit, connects the outdoor unit gas pipe and the plurality of indoor unit gas pipes, and connects the outdoor unit liquid pipe and the indoor unit liquid pipe.

The continuous refrigeration apparatus includes: a plurality of gas control units which are connected to the outdoor unit gas pipe, and branched to be connected to the plurality of indoor unit gas pipes respectively; a first pipe having one end connected to the outdoor unit liquid pipe and the other end connected to the indoor unit liquid pipe; and a second pipe connecting the first pipe and the plurality of gas control units.

Each of the plurality of gas control units includes: a first flow path connecting the gas control unit and the second pipe; a second flow path which is connected to the first flow path, and connects the outdoor unit gas pipe and the indoor unit gas pipe; and a third flow path connected in parallel with the second flow path.

Each of the plurality of gas control units includes: a first solenoid valve installed in the first flow path; a first check valve which is installed in the second flow path, installed closer to the outdoor unit side than a point where the first flow path and the second flow path are connected, and blocks a flow of the refrigerant flowing from the outdoor unit toward the first flow path and the second flow path; a second solenoid valve installed in the third flow path; and a second check valve which is installed in the third flow path, installed closer to the indoor unit side than the second solenoid valve, and blocks a flow of the refrigerant flowing from the indoor unit to the third flow path.

The continuous refrigeration apparatus includes: a defrost expansion valve installed in the first pipe; a first pipe check valve which is disposed in parallel with the defrost expansion valve, and blocks a refrigerant flow flowing from the indoor unit to the outdoor unit; and a second pipe check valve which is installed in the second pipe and installed closer to the liquid pipe side of the outdoor unit than the plurality of gas control units, and blocks a flow of the refrigerant flowing from the first pipe to the second pipe.

