JPH04214154A - Multi-chamber type air-conditioning machine - Google Patents

Abstract

PURPOSE:To prevent the deterioration of heating capacity by a method wherein the control timing of an inverter controller, controlling a frequency in accordance with a pressure in a pipeline between an indoor machine and a four-way valve, is deviated from the control timing of a controller, controlling the opening degree of the expansion valve of an outdoor machine in accordance with a refrigerant temperature in another pipeline between the indoor machine and the electric expansion valve of the outdoor machine. CONSTITUTION:Upon starting operation, a pressure detector 13 detects a pressure and compares it with a set pressure. When the detected pressure is higher, an inverter controller 14 reduces the operating frequency of a variable capacity compressor 2 but when the detected pressure is lower, the inverter controller 14 increases the operating frequency of the same. After a time DELTAT has elapsed, a refrigerant temperature detector 16 detects the temperatures of liquid tubes 11 of outdoor machines 7a-7d and compares them with a set temperature. When the detected temperature is higher, an outdoor machine side electric expansion valve 5 is closed by the expansion valve controller 17 of the outdoor machine 1 by a predetermined opening degree but when the detected temperature is lower, the expansion valve is opened by a predetermined opening degree. Indoor machine side electric expansion valves 8a-8d are controlled independently from the outdoor machine 1. According to this method, overcooling degree is controlled under a condition that a condensing pressure is stabilized whereby the operation of the title machine can be controlled optimally under a normal operation and an excessive operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-chamber air conditioner, and more particularly to a multi-chamber air conditioner in which individual control is performed during heating operation.

0002

[Background Art] In recent years, individual distributed air conditioning has been increasingly used for air conditioning in buildings, and the individual control of multi-room air conditioners, such as the invention disclosed in Japanese Patent Application Laid-open No. 1-21287, has been progressing. I've been exposed to it.

A conventional multi-room air conditioner of this type will be explained with reference to FIGS. 3 to 5.

FIG. 3 is a block diagram of a conventional multi-room air conditioner, FIG. 4 is a control flowchart for the outdoor unit, and FIG. 5 is a control flowchart for the expansion valve of the indoor unit.

In FIG. 3, an outdoor unit 1 of a multi-room air conditioner includes a variable capacity compressor 2, a four-way valve 3, an outdoor unit side heat exchanger 4, an outdoor unit side electric expansion valve 5, and an outdoor unit side fan 6. , and a plurality of indoor units 7a, 7b, 7 connected thereto.
c and 7d are indoor unit side electric expansion valves 8a and 8, respectively.
b, 8c and 8d, indoor unit side heat exchangers 9a, 9b, 9
c and 9d and indoor unit side fans 10a, 10b,
It is composed of 10c and 10d. In addition, the outdoor unit side electric expansion valve 5 and the indoor unit side electric expansion valves 8a and 8b are also provided.
, 8c and 8d are liquid pipes 11, which are connected to the indoor unit side heat exchanger 9a.
, 9b, 9c, and 9d and the four-way valve 3 are connected through gas pipes 12, respectively. Furthermore, in the outdoor unit 1, the four-way valve 3
An inverter 15 controlled by an inverter controller 14 in accordance with the detected pressure of a pressure detector 13 provided on a gas pipe 12 connected to the compressor 2 is connected to the variable capacity compressor 2 and to the electric expansion valve 5 on the outdoor unit side. Expansion valve controllers 17 that control the opening degree according to the temperature detected by a refrigerant temperature sensor 16 provided in the liquid pipe 11 are connected to the outdoor unit side motorized expansion valves 5, respectively. In addition, in the indoor units 7a, 7b, 7c and 7d, air temperature sensors 18a, 18b, 1 are arranged at the suction ports of the indoor unit side heat exchangers 9a, 9b, 9c and 9d, respectively.
Air conditioning load calculators 19a and 1 for the room are calculated from the amount of difference between the detected air temperatures 8c and 18d and the indoor temperature set on a remote controller (hereinafter referred to as remote controller, not shown).
Expansion valve controllers 20a, 20b, 20c and 20d which control the opening according to the air conditioning load calculated by 9b, 19c and 19d are the indoor unit side electric expansion valves 8a, 8b, respectively.
, 8c and 8d.

[0006] The operation of the multi-room air conditioner configured as described above will be explained using heating operation as an example.

The high temperature and high pressure refrigerant discharged from the variable capacity compressor 2 passes through the four-way valve 3 and the gas pipe 12 and flows into the indoor unit side heat exchangers 9a, 9b, 9c and 9d, where it is condensed and liquefied. The pressure is reduced in the outdoor unit side electric expansion valve 5 via the side electric expansion valves 8a, 8b, 8c and 8d and the liquid pipe 11, evaporated in the outdoor unit side heat exchanger 4, and passed through the four-way valve 3 again for variable capacity compression. Return to machine 2.

At this time, the capacity of the variable capacity compressor 2 is determined by the detected pressure (condensing pressure during heating) detected by the pressure detector 11 (S41) which changes depending on the air conditioning load at that time.
A predetermined pressure is read (S42), and the set pressure is compared with the piping pressure to calculate the differential pressure (S43). Then, the operating frequency of the variable capacity compressor 2 is determined in accordance with the differential pressure (S44), and the inverter 15 is controlled by the inverter controller 14 (S45). , when it is low, it is controlled in a high speed direction.

[0009] Also, the electric expansion valve 5 on the outdoor unit side is connected to the indoor units 7a, 7b, 7c and 7d, which is detected by the refrigerant temperature detector 16 (S46) which changes depending on the operating state at that time.
The temperature of the liquid pipe 11 between the and the outdoor unit side electric expansion valve 5 is compared with the read set temperature (S47) to calculate a temperature difference (S48). Then, the opening degree of the electric expansion valve 5 on the outdoor unit side is determined in accordance with this temperature difference (S49), and the outdoor unit is adjusted to a predetermined temperature (to a predetermined degree of supercooling). The side electric expansion valve controller 17 controls the valve to close when the detected temperature is higher than a predetermined temperature, and to open when the detected temperature is lower (S50).

Furthermore, indoor unit side electric expansion valves 8a, 8b,
8c and 8d are set using the room temperature set value set using the remote controller, the temperature of the intake air of the indoor units 7a, 7b, 7c, and 7d detected by the air temperature detectors 18a, 18b, 18c, and 18d (S51), and the remote controller. The air conditioning load calculators 19a, 19b, 19
The air conditioning load of the room is calculated from c and 19d (S53
), the opening degrees of the indoor unit-side electric expansion valves 8a, 8b, 8c, and 8d are determined according to the calculated air conditioning load (S5
4) When the air conditioning load is large, it is controlled in the open direction, and when it is small, it is controlled in the closed direction (S55).

The operating frequency of the variable capacity compressor 2 of the outdoor unit 1, the opening degree of the electric expansion valve 5 on the outdoor unit side, and the opening degree of the electric expansion valves 8a, 8b, 8c and 8d on the indoor unit side are each independent. controlled by

0012

However, in the above configuration, the operating frequency of the variable capacity compressor 2 and the opening degree of the electric expansion valve 5 on the outdoor unit side are both controlled elements on the outdoor unit 1 side, so they cannot be synchronized. It is controlled at the specified control timing.

[0013]Therefore, there is no problem in normal operating conditions, but in transient operating conditions, there is a problem in that the heating capacity is reduced due to an excessive rise in discharge temperature and a decrease in suction pressure.

That is, during start-up operation, which is a transient operating state, or when there is a sudden change in the operating state, for example, when the number of indoor units 1 in operation suddenly changes from four to one, supercooling occurs due to changes in condensing pressure. Since the speed of change in temperature is slow, if the operating frequency of the variable capacity compressor 2 and the opening degree of the electric expansion valve 5 on the outdoor unit side are controlled simultaneously, the degree of supercooling will change while the condensing pressure is changing. Even if the opening degree of the electric expansion valve 5 on the outdoor unit side is reduced, a reverse response occurs in which the degree of supercooling decreases.
The opening degree of the electric expansion valve 5 on the outdoor unit side becomes too small than the designed opening degree, and when the transition state changes to the normal condition over time, the opening degree of the electric expansion valve 5 on the outdoor unit side does not return to normal. Excessive throttling of No. 5 causes an excessive rise in discharge temperature and a drop in suction pressure, resulting in problems of low reliability and poor comfort.

[0015] The present invention solves the above problems.
The present invention provides a multi-room air conditioner that is highly reliable and provides excellent comfort, which does not cause a decrease in heating capacity due to an excessive rise in discharge temperature or a decrease in suction pressure even in a transient operating state.

[0016]

[Means for Solving the Problems] In order to solve the above problems, the present invention shifts the control timings of the inverter controller 14 and the expansion valve controller 17 of the outdoor unit 1.

[0017]

[Function] With the above configuration, the ability to control the degree of supercooling that changes slowly, that is, the opening degree of the expansion valve 5 on the outdoor unit side, can be controlled in transient operating conditions such as startup or sudden changes in operating conditions. This is done after the operating frequency of the variable compressor 2 is controlled and the condensing pressure is almost stabilized, so the electric expansion valve 5 on the outdoor unit side
Excessive throttling is prevented, and an excessive rise in discharge temperature and a drop in suction pressure do not occur.

[0018]

[Embodiment] An embodiment of the present invention will be explained with reference to FIGS. 1 and 2. However, since the configuration of the multi-room air conditioner is the same as the conventional one, a description thereof will be omitted.

FIG. 2 shows an inverter controller 1 that controls the operating frequency of the variable capacity compressor 2, which is a control element of the outdoor unit 1.
4 and the control timing of the outdoor electric expansion valve controller 17 that controls the opening degree of the outdoor unit side electric expansion valve 5, and a time difference ΔT is provided between the two.

The operation of the multi-room air conditioner configured as described above will be explained by taking heating operation as an example. In addition,
Since the operation of the refrigerant is the same as in the conventional example, its explanation will be omitted.

When the multi-room air conditioner is operated, the pressure detector 13 first detects the current pressure (condensing pressure during heating) (S1), compares it with a preset predetermined pressure ( S2, S3, S4), if the detected pressure is higher, the inverter controller 14 instructs the variable capacity compressor 2 to lower the operating frequency via the inverter 15, and if it is lower, instructs the variable capacity compressor 2 to increase the operating frequency ( S5). Thereafter, when a period of ΔT has elapsed (S6), the refrigerant temperature detector 16 detects the temperature of the liquid pipes 11 of the indoor units 7a, 7b, 7c, and 7d at that time (S7), and compares it with a predetermined temperature. If the detected temperature is higher, the expansion valve controller 1 of the outdoor unit 1
7 instructs the outdoor unit side electric expansion valve 5 to close to a predetermined opening, and if it is lower, instructs to open to a predetermined opening (S8
, S9).

[0022] Also, the indoor unit side electric expansion valves 8a, 8b, 8
c and 8d are controlled independently of the control elements of the outdoor unit 1 as in the conventional example, and are connected to the room temperature setting value set by the remote control and the air temperature detectors 18a, 18b, 18c and 18d.
Air conditioning load calculators 19a, 19b, 19c are calculated based on the temperature of the intake air of indoor units 7a, 7b, 7c and 7d detected by
and the indoor unit 7a according to the air conditioning load calculated by 19d.
, 7b, 7c and 7d expansion valve controllers 20a, 20b
, 20c and 20d, the indoor unit side electric expansion valve 8a,
8b, 8c, and 18d are controlled in the open direction when the air conditioning load is large, and in the closed direction when it is small (S10
, S11).

At this time, the outdoor unit side electric expansion valve 5 of the outdoor unit 1 is controlled after a period of ΔT as the operating frequency of the variable capacity compressor 2 changes, so the condensation pressure of the refrigerant system remains almost stable. , the degree of supercooling is controlled in accordance with the condensing pressure, and proper control is performed both in normal operation and in transient operating conditions.

[0024]

[Effects of the Invention] As explained above, according to the present invention,
Not only during normal operation but also during transient operating conditions, the phenomenon of over-throttling the electric expansion valve on the outdoor unit side does not occur, and comfort is improved by reducing equipment reliability due to excessive rise in discharge temperature and reduced capacity due to decrease in suction pressure. A highly reliable multi-room air conditioner that does not deteriorate in performance can be obtained.

It goes without saying that the present invention has similar effects not only on multi-room air conditioners, but also on ordinary air conditioners with one indoor unit and one outdoor unit.

[Brief explanation of the drawing]

FIG. 1 is a control flowchart of an outdoor unit side control element of a multi-room air conditioner according to the present invention.

FIG. 2 is a control timing chart of the outdoor unit side control elements of the multi-room air conditioner according to the present invention.

FIG. 3 is a configuration diagram of a conventional multi-room air conditioner.

FIG. 4 is a control flowchart of a conventional outdoor unit side control element.

FIG. 5 is a control flowchart of a conventional indoor unit side control element.

[Explanation of symbols]

1...Outdoor unit, 2...Variable capacity compressor, 3...Four-way valve, 4...Outdoor unit side heat exchanger, 5...Outdoor unit side electric expansion valve, 6...Outdoor unit side fan, 7a, 7b, 7c, 7
d...Indoor unit, 8a, 8b, 8c, 8d...Indoor unit side electric expansion valve, 9a, 9b, 9c, 9d...Indoor unit side heat exchanger, 10a, 10b, 10c, 10d...Indoor unit side fan, 11... Liquid pipe, 12...Gas pipe, 13
...Pressure detector, 14...Inverter controller, 15
...Inverter, 16...Refrigerant temperature detector, 17,
20a, 20b, 20c, 20d...expansion valve controller,
18a, 18b, 18c, 18d...air temperature sensor,
19a, 19b, 19c, 19d...Air conditioning load calculator.

Claims (1)

[Claims] Claim 1: An outdoor unit equipped with a compressor whose capacity is variable by an inverter, a four-way valve, a heat exchanger, and an electric expansion valve, and a plurality of indoor units each equipped with an electric expansion valve and a heat exchanger are connected in parallel. an inverter controller that controls the frequency of the inverter according to the detected pressure of a pressure detector installed in the piping between the indoor unit and the four-way valve, and an electric expansion valve between the indoor unit and the outdoor unit. An expansion valve controller that controls the electric expansion valve opening degree of the outdoor unit according to the temperature detected by the refrigerant temperature sensor installed in the piping, and the intake air temperature and room temperature settings detected by the air temperature sensor installed in the indoor unit. In a multi-room air conditioner equipped with an expansion valve controller that controls the electric expansion valve opening degree of the indoor unit according to the air conditioning load calculated by the air conditioning load calculator from the value, the inverter controller and the outdoor unit A multi-room air conditioner characterized by staggered control timing with an expansion valve controller.