JPH04273955A - Multiple room effect air conditioning equipment - Google Patents

Abstract

PURPOSE:To provide a multiple room effect air conditioning equipment wherein an air conditioner in inoperative condition can be prevented from the retention of refrigerant which may cause the lack of the refrigerant in the refrigerating cycle, when one of a plurality of indoor air conditioners is operating for room heating and the other is not. CONSTITUTION:At the time of heating operation, the degree of opening of a motor-driven expansion valve 8 on an indoor side is controlled by a control means 13 for an indoor air conditioner which has stopped its heating operation to activate a stopping control means 15, so that the subcooling value of refrigerant at the outlet opening of a heat exchanger 9 on the indoor side detected by a subcooling detection means 18 reaches the subcooling value during the operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner, and more particularly to the control of a stopped indoor unit when operating indoor units and stopped indoor units coexist during heating operation.

0002

[Prior Art] In recent years, individual air conditioning has been progressing in building air conditioning, and indoor units are installed in multiple rooms with different loads.
Even in multi-room air conditioners that are connected to one outdoor unit, individual air conditioning control for each room, as proposed in Japanese Patent Application Laid-open No. 1-212870, has been progressing.

[0003] The conventional technology will be explained below with reference to the drawings.
explain. In FIG. 4, 1 is an outdoor unit of a multi-room air conditioner, which includes a variable capacity compressor 2, a four-way valve 3, and an outdoor heat exchanger 4.
, an outdoor electric expansion valve 5, and an outdoor fan 6 are installed. Four indoor units 7a to 7d are connected in parallel to the outdoor unit 1, and are provided with indoor electric expansion valves 8a to 8d, indoor heat exchangers 9a to 9d, and indoor fans 10a to 10d, respectively. Reference numeral 11 denotes a pressure sensor, which is installed in the pipe inside the outdoor unit 1 between the four-way valve 3 and the indoor heat exchangers 9a to 9d. An inverter 12 controls the frequency of the variable capacity compressor 2 based on the pressure detected by the pressure sensor 11.

[0004] The operation of the multi-room air conditioner configured as above will be explained. First, in cooling operation, the high temperature and high pressure refrigerant discharged from the variable capacity compressor 2 passes through the four-way valve 3, flows into the outdoor heat exchanger 4, condenses and liquefies, and passes through the outdoor electric expansion valve 5. It is distributed by piping to the indoor units 7a to 7d, is depressurized by the indoor electric expansion valves 8a to 8d, is evaporated in the indoor heat exchangers 9a to 9d, and returns to the variable capacity compressor 2 via the four-way valve 3. .

In heating operation, the high temperature and high pressure refrigerant discharged from the variable capacity compressor 2 is distributed to each of the indoor units 7a to 7d via the four-way valve 3. The refrigerant is supplied to each indoor heat exchanger 9.
It is condensed and liquefied in a to 9d, passed through the indoor electric expansion valves 8a to 8d, is depressurized by the outdoor electric expansion valve 5, evaporated in the outdoor heat exchanger 4, and is converted into a liquid through the four-way valve 3. Return to compressor 2.

Further, in order to stop the operation of the indoor unit 7a that does not require air conditioning operation, the indoor electric expansion valve 8a is fully closed to cut off the refrigerant flow path, the indoor fan 10a is stopped, and the operation is stopped. Stop.

At this time, the capacity of the variable capacity compressor 2 is determined by the pressure sensor 11, which adjusts the inverter to a predetermined pressure based on the detected pressure (condensing pressure during heating) that changes depending on the air conditioning load at that time. 12 is performed by increasing or decreasing the frequency of the variable capacity compressor 2.

[0008]

[Problems to be Solved by the Invention] However, in the above configuration, when there are indoor units in operation and indoor units that are stopped, the indoor electric expansion valve of the stopped indoor unit is closed to the indoor side during cooling operation. Since it is located upstream of the heat exchanger, the refrigerant does not flow into the indoor heat exchanger, but on the other hand, during heating operation, the indoor electric expansion valve is located downstream of the indoor heat exchanger. , the refrigerant will be cut off at the outlet side of the heat exchanger.

Therefore, even if the indoor fan is stopped,
Due to heat exchange by natural convection, the refrigerant in the indoor heat exchanger gradually condenses and gradually stagnates in the indoor heat exchanger. As a result, the amount of refrigerant circulating in the refrigeration cycle decreases, resulting in insufficient heating capacity and an increase in the degree of superheating of the refrigerant sucked into the compressor, causing the compressor temperature to rise excessively.
This was a major issue in terms of comfort and reliability.

[0010]The present invention therefore solves the above-mentioned conventional problems, and prevents refrigerant from stagnation in the stopped indoor units when operating and stopped indoor units coexist, thereby improving individual distributed air conditioning using a multi-room air conditioner. The aim is to improve comfort and reliability.

[0011]

[Means for Solving the Problem] In order to solve this problem, the multi-room air conditioner of the present invention includes an indoor unit control means provided for each indoor unit for controlling an indoor electric expansion valve, and an indoor unit control means for controlling an indoor electric expansion valve. The indoor unit control means for the indoor unit that has stopped the heating operation during the heating operation is controlled by the heating operation control means when the heating operation is stopped. so that the value of the degree of supercooling detected by the degree of supercooling detection means of the same indoor unit that has stopped is the value of the degree of supercooling during operation,
The opening degree of the indoor electric expansion valve is controlled.

0012

[Operation] With the above-described configuration, the multi-room air conditioner of the present invention detects the degree of subcooling of the refrigerant at the outlet of the heat exchanger of the indoor unit that has stopped the heating operation during heating operation, and detects the degree of subcooling of the refrigerant at the outlet of the heat exchanger of the indoor unit that has stopped the heating operation. By controlling the opening degree of the indoor electric expansion valve so that the degree of subcooling is the same as the degree of subcooling during operation, and controlling the amount of refrigerant that stays in the indoor heat exchanger, the refrigeration cycle can be adjusted with or without a stopped indoor unit. This eliminates changes in the amount of refrigerant circulating within the compressor, thereby preventing a decrease in heating capacity and an excessive increase in the degree of superheating of the refrigerant sucked into the variable capacity compressor.

[0013]

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. Components that are the same as the conventional ones are denoted by the same reference numerals, and in the figures in which detailed description thereof is omitted, 13 is an indoor This is indoor unit control means provided in each of the machines 7a to 7d, and consists of an operation control means 14 and a stop control means 15. A room temperature sensor 16 detects the room temperature of the air-conditioned environment. Reference numeral 17 is a remote control for starting and stopping each indoor unit and setting the room temperature. 18 is a subcooling degree detection means, which is installed in the pipes connecting the indoor heat exchangers 9a, 9b, 9c, and 9d and the indoor electric expansion valves 8a, 8b, 8c, and 8d in FIG. 2, respectively. .

It should be noted that each component shown in FIG.
When distinguishing between 7d and 7d, add an alphabetic subscript to the code.

Next, the operation of the above configuration will be explained. A case where the multi-room air conditioner of this embodiment during heating operation includes indoor units that are in heating operation and indoor units that are stopped will be described.

When the outdoor unit is in heating operation, the indoor units 7a, 7b,
7c, 7d are remote controllers 17a, 17b, 17c, 17d
Assume that the indoor units 7a, 7b, and 7d are set to run, run, stop, and run, respectively.
After that, branch to STEP 2 to the stop side). Indoor units 7a, 7b, 7d in heating operation are indoor fans 10a, 10b, 1
0d is operated, room temperature sensors 16a, 16b, 16d
The operating control means 14a of each indoor unit control means 13a, 13b, and 13d uses the detected room temperature as a control input,
14b, 14c, the indoor electric expansion valves 8a, 8b,
The opening degree of the valve 8d is controlled to control the room temperature to the respective room temperature set value (STEP 3, STEP 4, STEP 7).

In the stopped indoor unit 8c, the indoor fan 10
c is stopped, and the opening degree of the electric expansion valve 8c is stopped so that the degree of subcooling of the refrigerant detected by the degree of subcooling detection means 18c becomes the same degree of subcooling as during operation (for example, 10 K) set in advance. Control is performed by the time control means 15c (STE
P5, STEP 6, STEP 7).

At this time, the indoor fan 10c is stopped and the condensing capacity of the indoor heat exchanger 9c is very small, but the liquid refrigerant present in the indoor heat exchanger 9c is Since the degree of subcooling at the outlet of the container 9c is controlled to be the same as the value during operation, the amount of liquid refrigerant is approximately the same as the amount during operation.

Therefore, the refrigerant distribution within the refrigeration cycle is the same as when the indoor unit 7c is operating, so that an optimum amount of refrigerant always circulates within the refrigeration cycle. For this reason, each indoor unit 7 in the refrigeration cycle
Even if a, 7b, 7c, and 7d are individually stopped, they can always operate in the same state, and can always operate efficiently with the optimum amount of refrigerant.

[0020]

As described above, the multi-room air conditioner of the present invention includes an indoor unit control means provided for each indoor unit for controlling the indoor electric expansion valve, an indoor heat exchanger, and an indoor unit control means for controlling the indoor electric expansion valve. During heating operation, the indoor unit control means for the indoor unit that has stopped heating operation detects the degree of subcooling provided in the piping between the electric expansion valves. The degree of opening of the indoor electric expansion valve is controlled so that the value of the degree of subcooling detected by the degree of subcooling detection means becomes the value of the degree of subcooling during operation.

[0021] Since the present invention configures a multi-room air conditioner as described above, even if a plurality of indoor units are individually operated or stopped, the refrigerant distribution state within the refrigeration cycle is consistent with the operation of the indoor units.・Since the amount of refrigerant circulating in the refrigeration cycle remains constant regardless of whether it is stopped, the amount of refrigerant circulating in the refrigeration cycle is always the optimum amount, and there is no refrigerant shortage due to excessive accumulation of refrigerant in the stopped indoor unit, and comfort is reduced due to a decrease in capacity. It also has great effects, such as preventing a decrease in reliability due to an excessive rise in the temperature of the variable capacity compressor due to an excessive rise in the degree of superheating of the refrigerant sucked into the variable capacity compressor.

[Brief explanation of the drawing]

[Fig. 1] Block diagram of a control system of a multi-room air conditioner that is an embodiment of the present invention.

[Figure 2] Refrigeration cycle diagram of the multi-room air conditioner of the same example

[Fig. 3] Flowchart of controlling the indoor unit of the multi-room air conditioner according to the same embodiment.

[Figure 4] Refrigeration cycle diagram of a conventional multi-room air conditioner

[Explanation of symbols]

1 Outdoor unit 2 Variable capacity compressor 3 Four-way valve 4 Outdoor heat exchanger 5 Outdoor electric expansion valves 7a, 7b, 7c, 7d Indoor units 8a, 8b, 8c, 8d Indoor electric expansion valves 9a, 9
b, 9c, 9d Indoor heat exchanger 13 Indoor unit control means 15 Stop control means 18 Supercooling degree detection means

Claims (1)

[Claims] Claim 1: An outdoor unit equipped with a variable capacity compressor, a four-way valve, an outdoor heat exchanger, and an outdoor electric expansion valve; an indoor electric expansion valve and an indoor heat exchanger; A plurality of indoor units connected in parallel, an indoor unit control means provided for each indoor unit for controlling the indoor electric expansion valve, and piping between the indoor heat exchanger and the indoor electric expansion valve. During the heating operation, the indoor unit control means of the indoor unit that has stopped the heating operation is configured to control the degree of subcooling detection means of the same indoor unit that has stopped the heating operation by the stop control means. A multi-room air conditioner characterized in that the degree of opening of the indoor electric expansion valve is controlled so that the value of the degree of subcooling detected is the value of the degree of subcooling during operation.