JPH037855A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable a proper recovery of refrigerant to be always carried out irrespective of a difference in capacity of each of indoor devices and irrespective of a difference in pipe lengths by a method wherein a control means for setting an interval time or an executing time of a refrigerant recoverying time in response to a capacity of its corresponding indoor device and a pipe length is provided. CONSTITUTION:An indoor control part 70 for an indoor device C1 may calculate a difference between a sensed temperature of an indoor temperature sensor 72 and a set temperature defined by an operating part 71. A frequency setting signal F1 corresponding to the temperature difference is transmitted to a multi-control part 60 as a requested cooling capability. The multi-controller 60 may count an interval time N by an internal timer and execute a refrigerant recoverying operation of a period (t) for every counting operation is up. Provided that if the compressor is turned off for its operation, a refrigerant recoverying operation is not carried out, but the compressor may wait an operation. The refrigerant recoverying operation is executed after the compressor is turned on. At this time, the interval time N of the refrigerant recoverying operation and the executing time (t) are set in response to a horse power of the indoor device and a pipe length (l).

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a multi-type air conditioner consisting of an outdoor unit and a plurality of indoor units.

(Prior Art) Generally, this type of air conditioner includes one shown in FIG. 3.

A is an outdoor unit and has a variable capacity compressor. Then, connect branch unit B to this outdoor unit A,
The branch unit B has multiple indoor units C1, C2,
C3 is connected.

That is, the indoor units c, , C2, , C3 set the required capacity according to their respective air conditioning loads using the frequency setting signal F1.
F2. Send it to branch unit B as F3.

Branching unit B receives the received frequency setting signal Fl.
* F2 r Determine the required capacity of each indoor unit from F3, and send the frequency setting signal Fo corresponding to the sum to the outdoor unit A.

The outdoor unit A controls the operating frequency of the compressor according to the frequency setting signal Fo that is sent.

Further, the branch unit B periodically performs a refrigerant recovery operation for the indoor unit that is not operating.

This refrigerant recovery operation is for recovering the refrigerant that has liquefied and settled in the indoor heat exchanger into the compressor of the outdoor unit and ensuring a sufficient oil level in the compressor.

(Problem to be solved by the invention) However, each indoor unit has a difference in capacity and a difference in piping length, and simply regular refrigerant recovery operation as described above may result in insufficient recovery or excessive recovery, resulting in so-called unmatching. This causes the refrigeration cycle to become unstable.

This invention was made in view of the above circumstances,
The purpose is to provide an air conditioner that can always perform appropriate refrigerant recovery and enable stable operation of the refrigeration cycle, regardless of differences in the capacity of each indoor unit or pipe length. It is in.

[Structure of the Invention] (Means for Solving the Problems) An air conditioning system that includes an outdoor unit and a plurality of indoor units, and that periodically performs a refrigerant recovery operation for an indoor unit that is out of operation among the indoor units during heating operation. The apparatus is provided with a control means for setting the interval time or execution time of the refrigerant recovery operation according to the capacity and piping length of the corresponding indoor unit.

(Function) The interval time or execution time of the refrigerant recovery operation is set according to the capacity and piping length of the indoor unit whose operation is stopped.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In the drawings, the same parts as in FIG. 3 are given the same reference numerals, and their explanations will be omitted.

As shown in FIG. 1, the outdoor unit A is equipped with a variable capacity compressor 1. As shown in FIG.

This compressor 1 includes a four-way valve 2, an outdoor heat exchanger 3, a parallel body of an expansion valve 4 for heating and a check valve 5 for forming a cooling cycle, a liquid tank 6, electric flow rate adjustment valves 11, 21, 31, and an air conditioner. A parallel body of expansion valves 12, 22° 32 for heating cycles and check valves 13, 23° 33 for forming heating cycles, indoor heat exchangers 14, 24,
34, Gas side on-off valve (electromagnetic on-off valve) 15.25, 35,
The accumulator 7 and the like are successively connected to form a heat pump type refrigeration cycle.

The above-mentioned cooling expansion valves 12, 22, and 32 each have a temperature sensing tube 1.
2a, 22a, and 32a, and these temperature sensing cylinders are attached to the gas side refrigerant pipes of the indoor heat exchangers 14, 24, and 34, respectively.

The indoor heat exchangers 14, 24, and 34 have different capacities (hereinafter referred to as horsepower), and for example, indoor unit C.
1 has 4 horsepower, indoor unit C2 has 3 horsepower, and indoor unit C3 has 2 horsepower.

In addition, the indoor heat exchangers 14, 24, and 34 have different piping lengths from the branch unit B, with the piping length of the indoor unit C1 being Ω1, and the piping length of the indoor unit C2 being Ω12.
, the piping length of the indoor unit C3 is 93.

In addition, during cooling operation, the refrigerant is caused to flow in the direction of the solid line arrow shown in the figure to form a cooling cycle, and during heating operation, the refrigerant is caused to flow in the direction of the broken line arrow shown by the switching operation of the four-way valve 2 to form a heating cycle. ing.

The control circuit is shown in FIG.

The outdoor unit A includes an outdoor control section 50. This outdoor control unit 50 is composed of a microcomputer and its peripheral circuits, and is connected to an inverter circuit 51 externally.

The inverter circuit 51 rectifies the voltage of the AC power supply 52,
The voltage is converted into an AC voltage of a predetermined frequency by switching according to a command from the outdoor control unit 50, and the compressor motor IM
It is supplied as driving power to the

Branching unit B includes a multi-control unit 60. This multi-control unit 60 is composed of a microcomputer and its peripheral circuits, and externally includes flow rate regulating valves 11, 21.3.
1 and an on-off valve 15□25°35 are connected.

The indoor units C1+ c21 c3 are equipped with indoor control sections 70, 80, and 90. These indoor control units are
It consists of a microcomputer and its peripheral circuits, and is connected to the outside with operation control units 71, 81.91 and indoor temperature sensors 72, 82.92, respectively.

In the outdoor control section 50, the multi-control section 60, and the indoor control sections 70, 80.90, the indoor unit c,
, a control means for controlling the operating frequency of the compressor 1 (output frequency of the inverter circuit 51) according to the required capacity of the indoor units c1., C2, and C3 during heating operation. c2. Among c3, the control means periodically performs refrigerant recovery operation for the indoor unit that is out of operation, and the capacity and piping length of the indoor unit (indoor unit that is out of operation) corresponding to the interval time and execution time of this refrigerant recovery operation. It is equipped with control means for setting accordingly.

Next, the operation in the above configuration will be explained.

It is assumed that all indoor units are currently performing cooling operation.

At this time, the indoor control section 70 of the indoor unit C1 calculates the difference between the temperature detected by the indoor temperature sensor 72 and the set temperature determined by the operation operation section 71, and requests a frequency setting signal F1 corresponding to the temperature difference. Multi-control unit 60 as cooling capacity
Transfer to.

Similarly, the indoor control section 80.9 of the indoor units C2 and C3
0 is also the frequency setting signal F2. F3 is transferred to the multi-control unit 60 as the required cooling capacity.

The multi-control unit 60 determines the required cooling capacity of each indoor unit based on the transferred frequency setting signal, and generates a frequency setting signal F corresponding to the sum total.

is transferred to the outdoor control unit 50.

The outdoor control unit 50 receives the transferred frequency setting signal Fo.
The operating frequency of the compressor 1 is controlled based on.

Note that the multi-control unit 60 includes indoor units C1+02,
The opening degree of the corresponding flow rate adjustment valve 11, 21.31 is controlled according to the required cooling capacity of C3, and the indoor heat exchanger 14
, 24 and 34 to maintain a constant degree of refrigerant superheat.

On the other hand, in heating operation, the flow of refrigerant is reversed and similar capacity control is performed.

During this heating operation, the multi-control unit 6o periodically executes a refrigerant recovery operation for the indoor unit that is not operating.

For example, if the indoor unit C1 is out of operation, the flow rate adjustment valve 11 is opened while the gas side on-off valve 15 is closed, and the refrigerant that has liquefied and remains in the indoor heat exchanger 14 is transferred to the compressor 1. to recover.

If the indoor unit C2 is out of operation, the flow rate adjustment valve 21 is opened while the gas side on-off valve 25 is closed, and the refrigerant that has liquefied and remains in the indoor heat exchanger 24 is recovered to the compressor 1. .

If the indoor unit C3 is not operating, the flow rate adjustment valve 31 is opened while the gas side on-off valve 35 is closed, and the refrigerant that has liquefied and remains in the indoor heat exchanger 34 is recovered to the compressor 1. .

During this refrigerant recovery operation, the multi-control unit 60 calculates and sets the opening degree θn of the flow rate adjustment valve according to the horsepower Nln of the corresponding indoor unit as shown in the following formula.

θn-fl　　(Nin) Note that fl is a function.

Further, the multi-control unit 60 controls the execution time t of the refrigerant recovery operation.
and the interval time N is the horsepower of the indoor unit Nl
Calculate and set according to the formula below according to n and piping length g.

t = f2 (Nin) ・f3C1)N-1y[
f2 (Nin) ・f3 (Q) Note that f2.
f3 is a function.

That is, the multi-control unit 6o counts the interval time N using an internal timer, and executes the refrigerant recovery operation for t hours every time the count increases. However, if the compressor 1 is off at the time of count-up, the refrigerant recovery operation is not performed and the system remains in a standby state, and the refrigerant recovery operation is executed after waiting for the compressor 1 to be turned on.

In this way, by setting the interval time N and execution time t of the refrigerant recovery operation according to the horsepower Nin and piping length g of the corresponding indoor unit, regardless of the difference in the horsepower Nin of the indoor unit and the piping length g, Appropriate refrigerant recovery can always be performed without shortage or excess.

Therefore, unmatching does not occur, and stable operation of the refrigeration cycle is possible.

Moreover, since the interval time N and the execution time t of the refrigerant recovery operation are individually set for each indoor unit, the refrigerant recovery operation is rarely executed simultaneously in a plurality of indoor units.

In other words, the decline in heating capacity can be minimized,
Sufficient reliability can be ensured.

In the above embodiment, both the interval time N and execution time t of the refrigerant recovery operation are made variable, but only one of them may be made variable. Further, although the case where the number of indoor units is three has been described, there is no limitation to the number.

In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without changing the gist.

[Effects of the Invention] As described above, according to the present invention, since the control means for setting the interval time or execution time of the refrigerant recovery operation according to the capacity and piping length of the corresponding indoor unit is provided, each indoor unit It is possible to provide an air conditioner that can always perform appropriate refrigerant recovery regardless of differences in capacity and pipe length, and enables stable operation of the refrigeration cycle.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a refrigeration cycle according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a control circuit of the same embodiment, and FIG. 3 is a diagram schematically showing the configuration of a conventional air conditioner. FIG. A...Outdoor unit, B...Branch unit, C1°C2, C3...Indoor unit, 1...Variable capacity compressor, 50...Outdoor control unit, 60...Multi control unit,
70°80.90... Indoor control section.

Claims (1)

[Claims] In an air conditioner that consists of an outdoor unit and a plurality of indoor units, and which periodically performs a refrigerant recovery operation for an indoor unit that is out of operation among the indoor units during heating operation, the interval time or execution time of the refrigerant recovery operation is An air conditioner characterized by having a control means for setting according to the capacity and piping length of a corresponding indoor unit.