JPH04327770A - Defrosting device in multi-chamber type air conditioner - Google Patents

Abstract

PURPOSE:To return refrigerant to an outdoor heat exchanger and perform a simple and high accurate defrosting of the outdoor heat exchanger by a method wherein a temperature sensing thermistor disposed at the outdoor heat exchanger is utilized when a heating operation is carried out and a degree of opening of an electric expansion valve corresponding to a stopped indoor device is controlled. CONSTITUTION:A multi-chamber type air conditioner is constructed such that a plurality of indoor devices 2 to 4 are connected to one outdoor device 1. In this case, a refrigerant adjusting mechanism corresponding to each of the indoor devices 2 to 4 and each of electric expansion valves 8 to 10 for use in controlling a refrigerant flow rate as well as a compressor 6, a four-way valve 6 and an outdoor heat exchanger 7 are disposed in the outdoor device 1. The outdoor heat exchanger 7 is provided with a thermistor 14 for sensing this temperature. A defrosting state for the outdoor heat exchanger 7 is detected by the thermistor 14, and a degree of opening of any one of each of electric expansion valves 8 to 10 corresponding to any one of each of the stopped indoor devices 2 to 4 is controlled. With such an arrangement, refrigerant is returned back to the outdoor heat exchanger 7 through each of the indoor heat exchangers 11 to 13 of each of the indoor devices 2 to 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting device for a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit through refrigerant piping.

0002

[Prior Art] In recent years, separate heat pump type air conditioners have been used in heating operation as much as possible during defrosting to prevent the heating capacity from being drastically reduced due to frost formation on the outdoor heat exchanger during heating. There is a strong need to reduce downtime so that occupants do not experience discomfort due to a drop in room temperature.

[0003] Conventionally, a defrosting device for a heat pump type air conditioner, not only a multi-chamber type air conditioner, which defrosts while continuing heating operation, has a configuration as shown in Fig. 2. . That is, the outdoor unit 101 and the indoor unit 10
2, the outdoor unit 101 includes a compressor 103, a four-way valve 104 for switching the refrigerant flow path, an outdoor heat exchanger 105, and an outdoor heat exchanger temperature detection device for detecting the temperature of the outdoor heat exchanger 105. A thermistor 106, a refrigerant throttling mechanism and an electric expansion valve 107 for controlling the refrigerant flow rate, and a two-way valve 108 for bypassing high and low pressure refrigerants are provided.

In the above configuration, when the outside air temperature is low during heating operation, frost forms on the outdoor heat exchanger 105, and this frost reduces the heat exchange function of the outdoor heat exchanger 105, causing the refrigeration cycle to deteriorate. As the overall capacity decreases,
The two-way valve 1 determines the frosting state of the outdoor heat exchanger 105 based on the temperature detected by the outdoor heat exchanger temperature detection thermistor 106, and temporarily bypasses high and low pressure.
08 is opened to increase the suction pressure of the refrigerant to the compressor 103, and the pressure inside the outdoor heat exchanger 105 increases as well as the refrigerant gas temperature, and as a result, the outdoor heat exchanger When the temperature of the outdoor heat exchanger 105 rises and the frost that has formed on the outdoor heat exchanger 105 melts, the heating capacity that has once decreased is restored again.

[0005]

[Problems to be Solved by the Invention] The conventional configuration of the defrosting device for an air conditioner requires a two-way valve 108 that bypasses the high pressure side and the low pressure side, which increases the cost. In the case of a two-way valve, it is either fully open or fully closed, so
Because fine-grained control corresponding to frost conditions cannot be performed,
There was a problem that a sufficient defrosting effect could not be obtained.

The present invention solves these problems by defrosting a multi-room air conditioner during heating operation without a two-way valve, and by defrosting precisely in response to frost conditions. The purpose is to do the following.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention connects a plurality of indoor units to one outdoor unit, and the outdoor unit includes an outdoor heat exchanger attached to an outdoor heat exchanger. A thermistor for detecting heat exchanger temperature and a number of electric expansion valves corresponding to each indoor unit are provided, and during heating operation, the detection value of the thermistor for detecting outdoor heat exchanger temperature is used to respond to stopped indoor units. The opening degree of the electric expansion valve is controlled to defrost the outdoor heat exchanger of the outdoor unit.

[0008]

[Operation] With the above-described configuration, when the multi-room air conditioner is in heating mode, when there are indoor units that are operating and indoor units that are stopped, the present invention is able to control the outdoor heat exchanger of the outdoor unit. When frost forms, the thermistor for detecting the temperature of the outdoor heat exchanger detects the frost state, and the electric expansion valve corresponding to the stopped indoor unit is opened nearly fully.
By returning the refrigerant to the outdoor heat exchanger through the indoor heat exchanger of the stopped indoor unit, the suction pressure to the compressor increases, which in turn increases the pressure inside the outdoor heat exchanger, and the refrigerant The gas temperature rises, and as a result, the outdoor heat exchanger temperature rises, making it possible to defrost the frost that has formed on the outdoor heat exchanger.

[0009]

Embodiment An embodiment of the present invention will be described below with reference to FIG.

As shown in the figure, a compressor 5 and a refrigerant flow path are installed inside the outdoor unit 1 of a multi-room air conditioner in which a plurality of indoor units 2, 3, and 4 are connected to one outdoor unit 1. an outdoor heat exchanger 7, a refrigerant throttling mechanism corresponding to each of the indoor units 2, 3, 4, and electric expansion valves 8, 9, 10 for controlling the refrigerant flow rate; 4 have indoor heat exchangers 11, 12,
The outdoor heat exchanger 7 is equipped with an outdoor heat exchanger temperature detection thermistor 14, and the outdoor heat exchanger temperature detection thermistor 14 is used to detect the outdoor heat exchanger temperature. electric expansion valves 8 and 9 corresponding to any of the indoor units 2, 3, and 4 that are stopped;
, 10 is controlled.

With the above configuration, for example, the indoor unit 2
, 3 are in heating operation and the indoor unit 4 is stopped. In normal operation, the opening degree of the electric expansion valve 10 corresponding to the stopped indoor unit 4 is the same as that of the indoor heat exchanger 1.
In order to prevent the refrigerant gas from condensing, it is controlled so that it is only slightly open. However, when frost forms on the outdoor heat exchanger 7 and the temperature detected by the outdoor heat exchanger temperature detection thermistor 14 falls below a certain value, the opening degree of the electric expansion valve 10 corresponding to the stopped indoor unit 4 is changed. Open nearly fully. Therefore, the high-pressure refrigerant that passes through the indoor heat exchanger 13 passes through the electric expansion valve 10 but is hardly depressurized, flows into the outdoor heat exchanger 7, and returns to the compressor 5 via the four-way valve 6. As a result, the suction pressure to the compressor 5 increases,
In conjunction with this, the pressure inside the outdoor heat exchanger 7 rises, and the refrigerant gas temperature rises, resulting in a drop in the outdoor heat exchanger 7.
temperature rises, and the frost that has formed on the outdoor heat exchanger 7 can be defrosted.

[0012]Furthermore, since the state of frost on the outdoor heat exchanger 7 is not constant due to the level of outside temperature and humidity, the temperature of the outdoor heat exchanger 7 is constantly detected and the temperature of the outdoor heat exchanger 7 is constantly detected. The suction pressure is constantly monitored, and the opening degree of the electric expansion valve 10 corresponding to the stopped indoor unit 4 is precisely controlled according to the decrease in the suction pressure, thereby responding to frost formation on the outdoor heat exchanger 7. This allows for detailed defrosting.

[0013]

Effects of the Invention As is clear from the above embodiments, according to the present invention, during heating operation, the outdoor heat exchanger temperature detection thermistor attached to the outdoor heat exchanger detects the By controlling the flow to the outdoor heat exchanger side depending on the opening degree of the electric expansion valve corresponding to the unit, a two-way valve for defrosting the outdoor heat exchanger is no longer necessary. In addition, since it is an electric expansion valve, it can be precisely controlled by its opening degree, so it is effective for defrosting multi-room air conditioners, such as finely defrosting depending on the frost on the outdoor heat exchanger. equipment can be provided.

[Brief explanation of drawings]

FIG. 1 is a refrigeration cycle diagram of a defrosting device for a multi-room air conditioner according to an embodiment of the present invention.

[Figure 2] Refrigeration cycle diagram of a conventional air conditioner defrost device

[Explanation of symbols]

1 Outdoor unit 2 Indoor unit 3 Indoor unit 4 Indoor unit 7 Outdoor heat exchanger 8 Electric expansion valve 9 Electric expansion valve 10 Electric expansion valve

Claims (1)

[Claims] Claim 1: A plurality of indoor units are connected to one outdoor unit, and the outdoor unit includes an outdoor heat exchanger temperature detection thermistor attached to an outdoor heat exchanger, and a thermistor corresponding to each indoor unit. A number of electric expansion valves are provided, and during heating operation, the opening degree of the electric expansion valve corresponding to the stopped indoor unit is controlled based on the detection value of the outdoor heat exchanger temperature detection thermistor, and the opening degree of the electric expansion valve corresponding to the stopped indoor unit is controlled. A defrosting device for a multi-room air conditioner configured to defrost an outdoor heat exchanger.