JPH0428970A - Multi-room type air conditioner - Google Patents

Abstract

PURPOSE:To get a complete liquid phase refrigerant before an indoor side expansion valve and prevent a reduction in capability by a method wherein the degree of opening of an indoor expansion valve of an indoor one for an indoor device located at a lower position is set lower than a degree of opening of an indoor side expansion valve of an indoor device mounted at a higher position. CONSTITUTION:Since an indoor device 7a is mounted at a position higher than an indoor device 7b by about 10m, refrigerant before an indoor side expansion valve 14 shows a pressure drop of a height difference of water column of 10m. At a valve degree of opening correction means 20 of the indoor device 7b, a throttling amount (S) of the expansion valve by about a height difference of 10m is calculated and a degree of opening of the indoor side expansion valve 16 is always set to be low by S than a degree of opening of the indoor side expansion valve 14. Accordingly, since the pressure drop of the height difference is accommodated by S, the condition in the indoor side expansion valve 14 and that of the expansion valve 16 are same from each other and an over-cooling degree is controlled in such a way as the refrigerant state becomes a liquid phase. Accordingly, it can be prevented that a flow are of the indoor device mounted at a higher position is extremely throttled and no capability is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multi-room air conditioner, and particularly to controlling the degree of subcooling during cooling operation.

2. Prior Art Regarding conventional multi-room air conditioners having multiple indoor units, various developments have already been made.
Multi-room air conditioners such as those shown in Figs. 8 to 1045 will be explained with reference to Fig. 8.

Reference numeral 1 denotes an outdoor unit of a multi-room air conditioner, which includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5, and an outdoor fan 6.

7a and 7b are indoor units, each with an indoor expansion valve ga.
, 8b, indoor heat exchanger 9a, 9b, indoor fan]
It consists of Qa and 10b.

The outdoor unit 1 and the indoor units 7a and 7b are connected in an annular manner by a liquid pipe 11 and a gas pipe 12 to form a refrigerant circuit 13.

Next, the operation of the multi-room air conditioner having the above configuration will be explained.

First, during cooling operation, high-temperature, high-pressure gas compressed by the compressor 2 passes through the four-way valve 3, condenses in the outdoor heat exchanger 4, becomes high-pressure liquid refrigerant, and passes through the outdoor expansion valve 5 to the indoor expansion valve. 8a
, 8b, and exchanges heat with indoor air in the indoor heat exchangers 9a and 9b to evaporate and become a low-temperature, low-pressure gas, which is then transferred to the compressor 2.
Return to At this time, if any of the indoor units is in a stopped state (for example, the indoor unit 7a), its indoor expansion valve is closed (for example, the indoor expansion valve 8a is closed) to prevent refrigerant from flowing into the stopped indoor unit. is driven by.

Next, during heating operation, the high-temperature, high-pressure gas compressed by the compressor 2 passes through the four-way valve 3 and exchanges heat with the indoor air in the indoor heat exchanger 9a + 9b, condenses, and becomes a high-pressure liquid refrigerant. The pressure is reduced at the outdoor expansion valve 5 via the expansion valves 8a and 8b,
It evaporates in the outdoor heat exchanger 4 to become a low-temperature, low-pressure gas and returns to the compressor 2. At this time, if any of the indoor units is in a stopped state (for example, the indoor unit 7a), its indoor expansion valve is slightly opened (for example, the indoor expansion valve 8a is slightly opened), and most of the refrigerant is in the stopped indoor unit. It is operated so that it does not flow.

Problems to be Solved by the Invention However, in recent years, individual distributed air conditioning has been progressing in building air conditioning, and this type of multi-room air conditioner has been introduced in so-called pencil buildings. Indoor units are not necessarily installed on the same floor, and may be installed at different heights, such as on the 3rd floor and 6N. At this time, with the above configuration, there is a problem in that during cooling operation, the state of the refrigerant in front of the indoor expansion valve becomes two-phase in some indoor units, resulting in inefficient indoor units.

In other words, for example, if a 10 horsepower outdoor unit is installed on the ground,
In cooling operation when a horsepower indoor unit is installed on the 1st floor and a 5 horsepower indoor unit is installed on the 4th floor, the indoor unit installed on the 4th floor (hereinafter referred to as indoor unit A) and the 1st floor There is a height difference of approximately 10 m between the installed indoor unit (hereinafter referred to as indoor unit B).
will occur.

As mentioned above, the state of the refrigerant during cooling operation is high-pressure liquid refrigerant at the outlet of the outdoor unit, and the pressure is reduced by the indoor expansion valve to become two-phase, so the inside of the liquid pipe connecting the outdoor unit and indoor unit is It becomes a liquid phase. Therefore, the pressure in front of the indoor expansion valves of indoor units A and B will drop by the amount of liquid column with a height difference of 10 m, so the degree of supercooling in front of the indoor expansion valve of indoor unit A will decrease. If the pressure drop due to the height difference of 10 m is not taken care of, the state of the refrigerant in front of the indoor expansion valve will become two-phase, making it difficult for the refrigerant to flow to the indoor heat exchanger of indoor unit A, resulting in insufficient capacity. It became a phenomenon.

The present invention solves the above-mentioned conventional problem, and when an outdoor unit is installed at the bottom and multiple indoor units are installed at the top, and there is a difference in height between the indoor units, when cooling operation is performed, the indoor units are installed at a high position. To provide a multi-room air conditioner in which the state of the refrigerant in front of the indoor expansion valve of an indoor unit is completely liquid, thereby preventing a decrease in performance.

Means for Solving the Problems In order to solve the above problems, the present invention provides a compressor, a four-way valve,
An outdoor unit consisting of an outdoor heat exchanger and an outdoor expansion valve is connected to a plurality of indoor units consisting of an indoor expansion valve and an indoor heat exchanger to form a ring-shaped refrigerant circuit, and the outdoor unit A multi-room air conditioner installed at a lower position than a plurality of indoor units, the plurality of indoor units being installed with a difference in height,
The opening degree of the indoor expansion valve of an indoor unit installed at a lower position among the plurality of indoor units is greater than the opening degree of the indoor expansion valve of an indoor unit installed at a higher position among the plurality of indoor units. It is a smaller version.

Effect The present invention has the above-described configuration, and when an outdoor unit is installed below and a plurality of indoor units are installed above, and there is a height difference between the indoor units,
The refrigerant in front of the indoor expansion valves of all indoor units is turned into a liquid phase to prevent a decrease in performance.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. In addition, the same reference numerals are given to the same parts as in the conventional art, and detailed explanation thereof will be omitted.

Figure 1 is a refrigeration cycle diagram of a multi-room air conditioner.
An indoor unit a is installed at a higher position among the plurality of indoor units, and has an indoor expansion valve 14, an indoor heat exchanger 9a, an indoor fan 10a, and a valve opening control means 15. Also 7b
is an indoor unit installed at a lower position among multiple indoor units,
Indoor expansion valve 16, indoor heat exchanger 9b, and indoor fan 10b.

It has a valve opening control means 15.

In addition, in this description, the multi-room air conditioner is installed in the following manner.

Outdoor unit 1...10 horsepower, indoor unit 7a installed on the ground...
・5 horsepower, installed indoor unit 7b on 41... 5 horsepower, 1
Installed on the floor FIG. 2 is a block diagram of the valve opening degree control means 15 that adjusts the valve opening degrees of the indoor expansion valves 14 and 16.

Next, regarding the operation of the above configuration, first, the cooling operation will be explained.

During cooling operation, high-temperature, high-pressure gas compressed by the compressor 2 passes through the four-way valve 3 and is condensed in the outdoor heat exchanger 4 to become a high-pressure liquid refrigerant, which passes through the liquid pipe 11 to the indoor expansion valve 14.16. The gas flows into the indoor heat exchangers 9a and 9b to exchange heat with indoor air, evaporates, becomes low-temperature, low-pressure gas, and returns to the compressor 2.

Further, the valve opening degrees of the indoor expansion valves 14 and 16 are determined by the operation detection means 17, the air conditioning/heating detection means 18, the load detection means 19
, is determined by the valve opening correction means 20, and is controlled to a predetermined opening for a predetermined time.

During cooling operation that operates in this manner, the indoor unit 7a is installed at a position approximately 10 m higher than the indoor unit 7b, so the pressure of the refrigerant in front of the indoor expansion valve 14 is reduced by a liquid column with a height difference of 10 m. It turns out. Therefore, in the valve opening degree correction means 20 of the indoor unit 7b, the expansion valve throttle amount (
S) is calculated, and the valve opening of the indoor expansion valve 16 is always set smaller than the valve opening of the indoor expansion valve 14 by S (for example, if the indoor loads are the same, the indoor expansion valve 1
The valve opening degree of No. 4 is 800 pulses, and the valve opening degree of the indoor expansion valve 16 is 600 pulses, however, S is 200 pulses).

Therefore, since the pressure drop due to the difference in height is always absorbed by S, the state of the refrigerant in front of the indoor expansion valves 14 and 16 is the same, and if the degree of supercooling is controlled so that the refrigerant state becomes liquid phase. This eliminates the problem of the flow rate of an indoor unit installed in a high position being extremely restricted and the capacity not being achieved as in the past.

Next, heating operation will be explained.

During heating operation, the high-temperature, high-pressure gas compressed by the compressor 2 passes through the four-way valve 3, exchanges heat with indoor air in the indoor heat exchangers 9a and 9b, condenses, and becomes a high-pressure liquid refrigerant. 1
4.16, the gas is depressurized by the outdoor expansion valve 5, evaporated by the outdoor heat exchanger 4, becomes a low-temperature, low-pressure gas, and returns to the compressor 2.

Further, the valve opening degrees of the indoor expansion valves 14 and 16 are determined by the operation detection means 17, the air conditioning/heating detection means 18, the load detection means 19
, is determined by the valve opening correction means 20, and is controlled to a predetermined opening for a predetermined time.

During heating operation that operates in this way, there is almost no pressure loss because high-pressure, high-temperature gas flows through the gas pipe 12, and since the liquid refrigerant flows in the liquid pipe 11 in the direction of gravity, there is no pressure drop, so the cooling It is not necessary to use the valve opening correction means 20 to adjust the throttle amount of the expansion valve for the height difference of 10 m as during operation, and it is sufficient to set the valve opening according to the load of each chamber.

As mentioned above, when the outdoor unit is at the bottom and the indoor unit is in the upper room, the valve opening of the indoor expansion valve of the indoor unit installed at a lower position is changed to the valve opening of the indoor expansion valve of the indoor unit installed at a higher position. By making the opening smaller than the opening degree, operation can be performed without deterioration of performance during cooling and heating.

In this embodiment, there are two indoor units, but the same applies to two or more indoor units. All you have to do is set the opening degree of the expansion valve.

Effects of the Invention As is clear from the above description, the present invention comprises an outdoor unit consisting of a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor m-force valve, an indoor expansion valve, and an indoor heat exchanger. A plurality of indoor units are connected to form an annular refrigerant circuit, the outdoor unit is installed at a lower position than the plurality of indoor units, and the plurality of indoor units are installed with a height difference. In the multi-room air conditioner, the opening degree of the indoor expansion valve of the indoor unit installed at a lower position among the plurality of indoor units is set to the indoor unit installed at a higher position among the plurality of indoor units. Since the opening degree is smaller than that of the indoor expansion valve, it is possible to operate an indoor unit installed at a particularly high position without reducing its capacity.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram of a multi-room air conditioner according to an embodiment of the present invention, Fig. 2 is a block diagram of the same control circuit, and Fig. 8 is a refrigeration cycle diagram of a conventional multi-room air conditioner. be. 2... Compressor, 3... Four-way valve, 4...
...Outdoor heat exchanger, 5...Outdoor expansion valve, 7a, 7b...Indoor unit, 9a, 9b...
...Indoor heat exchanger, 14.16...Indoor expansion valve, 15...Valve opening control means, 20...
...Valve opening correction means. Name of agent Patent attorney Shigetaka Awano 1 person 2- pressure 3-- at side 4 ・-嘗 外图张伜5-m-正太し 119 m Zhu Benba

Claims (1)

[Claims] An annular refrigerant circuit is constructed by connecting an outdoor unit consisting of a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve to multiple indoor units consisting of an indoor expansion valve and an indoor heat exchanger. , the outdoor unit is installed at a lower position than the plurality of indoor units, and the plurality of indoor units are installed with a difference in height, the indoor unit being lower than the plurality of indoor units. A multi-room air conditioner in which the opening degree of the indoor expansion valve of an indoor unit installed at a higher position is smaller than the opening degree of the indoor expansion valve of an indoor unit installed at a higher position among the plurality of indoor units. .