JPH04194555A - Multiroom air-conditioner - Google Patents

Abstract

PURPOSE:To keep cooling-capacity proper, by a method wherein in the time of cooling, a mean value for the degree of subcooling in each indoor machine is compared with the degree thereof preset, the amount of the heat-exchange of a liquid pipe for a gas pipe is regulated by a regulating means for the amount thereof, and the degree thereof is controlled at a specified value. CONSTITUTION:In the time of cooling, a high temperature gas with high pressure compressed by a compressor 3 is turned into a liquid refrigerant with the high pressure by a heat- exchanger 5 on the side of an outdoor machine, and the liquid refrigerant passes an expansion valve 6 on the side thereof, and its flow is divided into a bypass 11a and the liquid pipe 11. After the liquid refrigerant passing a liquid-to-gas heat-exchanger 14 is cooled with a gaseous refrigerant in a gas pipe 12a on the side of suction, it again joins in the liquid pipe 11 and flows into indoor machines 2a, 2b. The pressure of the liquid refrigerant is reduced by expansion valves 8a, 8b on the side of indoor machines and the heat-exchange of the liquid refrigerant for the indoor air is done by heat-exchangers 9a, 9b on the indoor side, so that the liquid refrigerant is turned into a low temp. gas with low pressure, and the gaseous refrigerant returns to the compressor 3 through a gas pipe 12. For the control of the degree of subcooling, time degree of subcooling of the liquid refrigerant is detected by detectors 20a, 20b and a mean value is calculated in an operation circuit 21. In a deciding circuit 22, the mean value is compared with the degree thereof preset, a regulating valve 13 is regulated by a regulator 23, a refrigerant flow rate in the heat-exchanger 14 is regulated, and the degree of subcooling is controlled at a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-chamber air conditioner, and more particularly to a multi-chamber air conditioner equipped with a supercooling degree control device.

(Prior Art) In recent years, as buildings become taller, outdoor units are often installed with a large difference in height from indoor units. Regarding this type of conventional multi-room air conditioner/machine, Refrigeration, Vol. 61, No. 708 (IO issue, 1986), P. 10
The multi-chamber air conditioners shown in numbers 38 to 1045 will be explained using the configuration diagram in FIG. 4 as an example.

In the figure, the multi-room air conditioner includes an outdoor unit 1 installed on the - floor, etc., drawn by a broken line, and a plurality of indoor units, also drawn with broken lines, installed in each room of the multi-story floor, etc. Machine 2a
and 2b.

Furthermore, the above outdoor unit l has a compressor 3. Four-way valve 4° outdoor unit side heat exchanger 5. From the outdoor unit side expansion valve 6 and the outdoor unit side fan 7, the indoor units 2h and 2b are connected to the indoor unit side expansion valves 8a and 8b, and the indoor unit side heat exchangers 9a and 9, respectively.
b. It consists of an indoor unit side fan loa and fob.

The outdoor unit 1 and the indoor units 2a and 2b are connected to the liquid pipes 1 which connect the expansion valves 6, 8a and 8b on the outdoor unit side and the indoor unit side, and the indoor unit side heat exchangers 9a and 9b. , via the four-way valve 4 and the outdoor unit side heat exchanger 5,
A refrigerant circuit 9 is constructed by connecting the expansion valves 8a, 8b, and 6 on the indoor unit side and the outdoor unit side, and further comprising the gas pipe 12 connecting the four-way valve 4 and the compressor 3. The operation of the configured multi-room air conditioner will be explained.

First, to explain about air conditioning, the high-temperature, high-pressure gas refrigerant compressed by the compressor 3 is branched at the four-way valve 4, condensed in the outdoor unit side heat exchanger 5, becomes high-pressure liquid refrigerant, and is turned into a high-pressure liquid refrigerant by the outdoor unit side expansion valve 6.
The liquid passes through the liquid pipe 11 and is depressurized by the indoor unit side expansion valves 8a and 8b, and is evaporated by exchanging heat with indoor air in the indoor unit side heat exchangers 9a and 9b to become a low-temperature, low-pressure gas, and returns to the compressor 3. At that time, the cold air is
By b, the room is bathed and cooled.

Next, during heating, the high-temperature, high-pressure gas compressed by the compressor 3 passes through the four-way valve 4 and gas pipe 12, exchanges heat with indoor air in the indoor unit heat exchangers 9a and 9b, and condenses. It becomes a high-pressure liquid refrigerant, enters Mt:l via the indoor unit side expansion valves 8a and 8b, is depressurized by the outdoor unit side expansion valve 6, evaporates in the outdoor unit side heat exchanger 5, becomes a low-temperature low-pressure scum, and is compressed. Return to machine 3.

(Problem to be Solved by the Invention) However, in the above configuration, when there is a large height difference, for example, the outdoor unit 1 is installed on the ground and the indoor units 2a and 2b are installed on the 8th or 9th floor. During cooling, the pressure of the liquid refrigerant in the liquid pipe 11 drops by the pressure head, and the degree of supercooling is no longer achieved, flash scum is generated upstream of the indoor unit expansion valves 8a and 8b, and the cooling capacity is reduced. There was a problem.

In addition, since the amount of pressure drop of the liquid refrigerant differs depending on the degree of height difference, for example, the degree of supercooling will be different when the indoor units 2a and 2b are installed on the 1st floor and when they are installed on the 9th floor.
There was also a problem that the indoor units 2a and 2b of the same capacity had different cooling capacities.

The present invention solves the above problems, and even when there is a long pipe or there is a height difference between the outdoor unit 1 and the indoor units 2a and 2b,
The present invention provides a multi-room air conditioner that can maintain an appropriate cooling capacity by controlling the degree of subcooling to a constant level during cooling operation.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides the above indoor unit 2.
In a and 2b, a degree of supercooling detection means for checking the degree of supercooling of the liquid refrigerant is installed in the liquid pipe 11 near the indoor unit side expansion valves 8a and 8b, and in the outdoor unit 1, A bypass is formed in the liquid pipe 11 near the side expansion valve 6 with a check valve to prevent it from flowing in during heating, and a control valve that adjusts the flow rate of the liquid refrigerant in the bypass and the suction side gas pipe of the compressor 3 are provided. A heat exchange variable heat exchange mechanism equipped with a heat exchange device, a supercooling degree calculation circuit that calculates the average supercooling based on the output signal of the above-mentioned supercooling degree detection means, and a calculation result and setting supercooling. A heat exchange amount control device is provided, which includes a supercooling degree determining circuit that compares the supercooling degree with the supercooling degree and determines the magnitude thereof, and a regulating valve adjusting means that adjusts the aforementioned regulating valve based on the determination result.

(Function) With the above configuration, during cooling, the degree of subcooling is determined by comparing the average value of the degree of subcooling of each indoor unit 2a and 2b with a predetermined set degree of supercooling using the degree of subcooling detection means. Based on this determination, the heat exchange amount adjustment means adjusts the amount of heat exchange between the liquid pipe and the gas pipe to control the degree of supercooling to a constant level. Even if there is a problem, it is possible to maintain an appropriate cooling capacity.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram of a multi-room air conditioner according to the present invention.
The difference from the conventional example shown in FIG. 4 is that the outdoor unit 1 is provided with a bypass lla in the liquid pipe 11 near the outdoor unit expansion valve 6;
A control valve 13 for adjusting the flow rate of the liquid refrigerant in the bypass Lla is provided between the branch points, and a liquid gas heat exchanger 14 with the suction side waste pipe 12a of the compressor 3 is provided in the center of the bypass Lla.
Furthermore, in order to prevent liquid refrigerant from flowing into the bypass 11a during heating, a heat exchange variable heat exchange device 16 equipped with a check valve 15 on the outlet side is provided, and indoor units 2a and 2b are provided with a heat exchanger 16 on the indoor unit side. Pressure sensors 17a and 1 measure the pressure and temperature of the liquid refrigerant in the liquid pipes near the expansion valves 8a and 8b.
7b, thermistors 18a and 18b, and a supercooling replacement microcomputer +9a and 19b that calculates the degree of supercooling from the 8 forces.
In addition, in addition to the fact that
A supercooling degree calculation circuit 21 that calculates the average value of the supercooling degrees of a and 2b, and a supercooling degree judgment that determines the supercooling degree by comparing a preset supercooling degree with the above average value. circuit 22, and a control valve adjustment device 2 that drives the control valve 13 of the variable heat exchange amount heat exchange device 16 based on the determination result thereof.
This is because a heat exchange amount control device 24 consisting of three components is provided. Since the rest is the same as the conventional example, the same components are given the same reference numerals and their explanations will be omitted.

In addition, an electric expansion valve is used for the above-mentioned control valve 13, and the liquid-gas heat exchanger 14 has a double pipe structure as shown in FIG. The liquid refrigerant was allowed to flow in the opposite direction as shown by arrow B through the surrounding outer tube, thereby exchanging heat between the liquid refrigerant and the gas refrigerant.

The operation of the multi-room air conditioner configured as above will be explained.

First, during cooling, the refrigerant flow is such that high-temperature, high-pressure gas compressed by the compressor 3 passes through the four-way valve 4 and is condensed in the outdoor unit side heat exchanger 5 to become a high-pressure liquid refrigerant. After passing through the expansion valve 6, the liquid is divided into a bypass 11a provided with the liquid-gas heat exchanger 14 and a liquid pipe 11 provided in the control valve 13. At this time, the liquid refrigerant passing through the liquid gas heat exchanger 14 is cooled by exchanging heat with the gas refrigerant in the suction side gas pipe 12a, and then passes through the check valve 5 and enters the liquid pipe 11 again. The water merges and flows into the indoor units 2a and 2b.

After being depressurized by the indoor unit side expansion valves 8a and 8b and becoming a cold gas refrigerant, it exchanges heat with indoor air in the indoor unit side heat exchangers 9a and 9b to become a low-temperature, low-pressure gas, which passes through the gas pipe 12 to the compressor. Return to 3.

The supercooling degree control at this time will be explained using the flowchart of FIG. 3.

First, it is determined whether or not it is cooling operation (step 25), and if it is cooling, the subcooling degree detection devices 20a and 20b detect the subcooling degree of the liquid refrigerant indoor unit (2a) -T, (deg ) After detecting the degree of supercooling = T 2 (deg) of the indoor unit (2b) (step 26), the degree of supercooling calculation circuit 21 calculates the average value T of the degrees of supercooling T, T, as a representative supercooling. The degree is calculated (step 27). The degree of supercooling determination circuit 22 compares the representative degree of supercooling T and the set degree of supercooling TB. If T<TB, that is, r N OJ, the control valve adjustment device 23 throttles the control valve 13 to control the liquid gas. The flow rate of refrigerant flowing into the heat exchanger 14 is increased (step 29).

Also, if the result of comparison with the set supercooling degree T8 (step 28) is T≧TB, that is, rYEs, then the supercooling degree determination circuit 2
2, the representative supercooling degree T and the set supercooling degree T.

(Step 30).

If T=TB, that is, rYESJ, it means that the representative degree of supercooling is the same as the set value, and the opening degree of the control valve 13 is not changed. If the comparison result is T8#TB, that is, rNOJ, it means that the representative supercooling degree is larger than the set value, and the control valve adjustment device 23 is activated.
The control valve 13 is opened (step 31) to reduce the flow rate of refrigerant flowing into the liquid-gas heat exchanger 14.

By repeating steps 25 to 31 above, the refrigerant flow rate of the liquid-gas heat exchanger 14 is adjusted to control the degree of supercooling to be constant.

Next, to explain the heating operation, since the capacity of the indoor unit heat exchangers 9a and 9b is greater than that of the outdoor unit side heat exchanger 5, the degree of subcooling is originally as high as 20 to 30 degrees, and the liquid gas heat exchange Since there is no need to circulate the refrigerant through the heat exchanger 14, the check valve 15 allows the liquid refrigerant to flow through the liquid-gas heat exchanger 1.
4, and as shown in the flowchart in Figure 3, it is determined whether or not to cool the air (step 25).
, heating, i.e., rNOJ, the control valve 13 is fully opened (step 32).

Note that the operation during heating is the same as in the conventional example, so the explanation thereof will be omitted.According to the above embodiment, during cooling, each indoor unit 2a and 2
By checking the degree of supercooling of b, it is possible to maintain an appropriate cooling capacity by controlling the degree of supercooling to a constant level even when the pipe is long or there is a difference in height between the outdoor unit 1 and the indoor units 2a and 2b. can.

Furthermore, during heating, the check valve I5 prevents liquid refrigerant from flowing into the liquid-gas heat exchanger 14, and the control valve 13 is fully opened, thereby preventing a drop in high pressure and maintaining the heating capacity.

In this embodiment, the amount of heat exchange between the bypass lla of the liquid pipe 11 and the suction side gas pipe +2a is adjusted by controlling the refrigerant flow rate by operating the control valve 13. It goes without saying that the same effect can be obtained by providing a number of filters and controlling the number of switches.

(Effects of the Invention) As explained above, according to the present invention, during cooling, the degree of subcooling of the liquid refrigerant detected near the upstream of the expansion valve on the indoor unit side is compared with the set degree of supercooling, and this is always set. To maintain the degree of supercooling, the flow rate of the bypass formed near the downstream of the expansion valve on the outdoor unit side is adjusted, and the heat exchange amount of the liquid gas heat exchanger installed between the bypass and the gas pipe on the suction side of the compressor is controlled. This makes it possible to maintain appropriate cooling performance even when there is a large height difference between the outdoor unit and the indoor unit or when there is long piping.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a multi-room air conditioner according to the present invention;
3 is a flowchart showing a program for supercooling degree control, and FIG. 4 is a configuration diagram of a conventional multi-room air conditioner. 1...Outdoor unit, 2a, 2b...Indoor unit, 3.
... Compressor, 4 ... Four-way valve, 5 ... Outdoor unit side heat exchanger, 6 ... Outdoor unit side expansion valve, 7 ...
Outdoor unit side fan, 8a, 8b... Indoor unit side expansion valve,
9'a, 9b... Indoor unit side heat exchanger, loa, 1
0b...Outdoor unit side fan, 11...Liquid pipe, lla...
··bypass. 12 ・ Gas pipe, 12a...Suction side gas pipe, 13
...Control valve, i4...Liquid gas heat exchanger, 15...
・Check valve, 16...Variable heat exchange amount heat exchange device, 17a
, 17b - pressure sensor, 18a. 18b...Thermistor, 19a, 19b...
Supercooling replacement microcomputer, 20a, 20b...Supercooling degree inspection device, 21... Supercooling degree calculation circuit, 22...
Supercooling degree determination circuit, 23... control valve adjustment device, 24.
...Heat exchange amount control device.

Claims (1)

[Claims] The outdoor unit includes a compressor, four-way valve, heat exchanger, and expansion valve.
In a multi-room air conditioner in which a plurality of indoor units are each equipped with a heat exchanger and an expansion valve, and both are connected via liquid pipes and gas pipes to form a ring-shaped refrigerant circuit, the above-mentioned indoor units include: A degree of supercooling detection means for detecting the degree of supercooling is provided in the liquid pipe near the expansion valve, and a bypass is provided in the liquid pipe near the expansion valve in the above outdoor unit, and this bypass is connected to the gas pipe on the suction side of the compressor. A variable heat exchange amount liquid gas heat exchange mechanism that performs heat exchange,
The average degree of supercooling is calculated by the degree of supercooling calculation means based on the output signal from the degree of supercooling detection means, and the calculated average degree of supercooling is compared with the set degree of supercooling to determine the degree of supercooling. A multi-chamber type, characterized in that it is provided with a heat exchange amount adjusting means for determining the amount of heat exchange by a supercooling degree determining means and adjusting the heat exchange amount of the variable heat exchange amount liquid gas heat exchange mechanism based on the determination result. Air conditioner.