Air conditioner and control method thereof

Abstract

Disclosed herein is a water-source heat-pump type air conditioner in which a receiver is connected to a super-cooler or economizer, and a control method of the air conditioner to reduce the quantity of liquid refrigerant collected in the receiver during a cooling / heating overload operation. When a cooling / heating overload operation occurs, an electric expansion valve associated with the super-cooler or the economizer is opened by a predetermined opening degree, to bypass high-pressure liquid refrigerant collected in the receiver, thereby preventing a rapid pressure increase due to a great quantity of liquid refrigerant collected in the receiver.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of Korean Patent Application No. 10-2010-0011650, filed on Feb. 8, 2010 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.BACKGROUND[0002]1. Field[0003]Embodiments relate to an air conditioner and a control method thereof, which may reduce the quantity of liquid-phase refrigerant collected in a receiver during a cooling / heating overload operation.[0004]2. Description of the Related Art[0005]Generally, although heat naturally moves from a high temperature region to a low temperature region, moving heat from a low temperature region to a high temperature region may require certain external action. This is the principle of a heat pump. A heat-pump type air conditioner performs a cooling or heating operation via reversible switching of a heat transfer mechanism based on a refrigeration cycle consisting of compression-condensation-expansion-evaporation of...

AI Technical Summary

Benefits of technology

[0009]Therefore, it is an aspect of the embodiment to provide an air conditioner and a control method thereof, which may reduce the quantity of liquid-phase refrigerant collected in a receiver during a cooling / heating overload operation, thus preventing a pressure increase.

[0011]In accordance with one aspect of the embodiment, an air conditioner includes a compressor to compress refrigerant, an outdoor heat exchanger to undergo heat exchange between the refrigerant and water, a receiver to store a part of the refrigerant that has undergone heat exchange with the water in the outdoor heat exchanger, and to divide the stored refrigerant into gas refrigerant and liquid refrigerant, a sub heat exchanger to perform super-cooling of the liquid refrigerant separated from the receiver, an electric expansion valve to bypass the liquid refrigerant separated from the receiver, a pressure sensor to sense a pressure of refrigerant discharged from a high-pressure side of the compressor, a temperature sensor to sense a temperature of the outdoor heat exchanger, and a control unit to determine whether or not a cooling / heating overload operation occurs based on an operation capacity of the compressor, the pressure of refrigerant at the high-pressure side and the temperature of the outdoor heat exchanger, and to control an opening degree of the electric expansion valve to reduce the quantity of liquid refrigerant collected in the receiver during the cooling / heating overload operation.

[0023]The control unit may counter a bypass operation time for which the liquid refrigerant inside the receiver is bypassed to the low-pressure side through the electric expansion valve having the increased opening degree, and may keep the electric expansion valve at an original opening degree if the bypass operation time exceeds a predetermined time.

[0025]In accordance with another aspect of the embodiment, a control method of an air conditioner, including a compressor to compress refrigerant, an outdoor heat exchanger to perform heat exchange between the refrigerant and water, a receiver to store a part of the heat-exchanged refrigerant to divide the stored refrigerant into gas refrigerant and liquid refrigerant, a sub heat exchanger to perform super-cooling of the liquid refrigerant and an electric expansion valve to bypass the liquid refrigerant, includes sensing a pressure of refrigerant discharged from a high-pressure side of the compressor, sensing a temperature of the outdoor heat exchanger, determining whether or not a cooling / heating overload operation occurs based on an operation capacity of the compressor, the pressure of refrigerant at the high-pressure side and the temperature of the outdoor heat exchanger, and bypassing the liquid refrigerant inside the receiver to reduce the quantity of liquid refrigerant collected in the receiver during the cooling / heating overload operation.

Problems solved by technology

The great quantity of liquid-phase refrigerant collected in the receiver may reduce a gas refrigerant space, i.e. a buffer space for alleviation of pressure variation, thus causing a rapid pressure increase due to operation capacity variation of the compressor changes or upon loading of the PWM type compressor.

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