EP3483524A1

EP3483524A1 - Control device of multiple-type air conditioning device, multiple-type air conditioning device, method of controlling multiple-type air conditioning device, and computer program of controlling multiple-type air conditioning device

Info

Publication number: EP3483524A1
Application number: EP18204568.2A
Authority: EP
Inventors: Masayuki Takigawa; Takahiro Kato; Tatsuhiro Yasuda; Tomohiro SAKAGUCHI
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2017-11-09
Filing date: 2018-11-06
Publication date: 2019-05-15
Also published as: JP2019086251A

Abstract

A control device of a multiple-type air conditioning device configured to perform control to adjust refrigerant when a necessary amount of refrigerant varies, the multiple-type air conditioning device, a method of controlling the multiple-type air conditioning device, and a computer program of controlling the multiple-type air conditioning device are provided. The present invention provides a control device 70 of a multiple-type air conditioning device 1 including at least one outdoor unit 2, and a plurality of indoor units 3 each including an indoor electronic expansion valve 31. Each indoor unit 3 in operation is referred to as an operation indoor unit 3, each operation indoor unit 3 in heating operation is referred to as a heating operation indoor unit 3, and each indoor unit 3 at a stop is referred to as a stop indoor unit 3. At heating, when the difference between an exit temperature T1 and a central-part temperature T2 of an indoor heat exchanger 30 included in each heating operation indoor unit 3 becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive, control is performed to close the indoor electronic expansion valves 31 of all stop indoor units 3.

Description

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to a control device of a multiple-type air conditioning device, the multiple-type air conditioning device, a method of controlling multiple-type air conditioning device, and a computer program of controlling the multiple-type air conditioning device.

2. DESCRIPTION OF RELATED ART

In a multiple-type air conditioning device, a necessary amount of refrigerant varies with, for example, operating conditions at cooling, heating, and the like, and air conditions such as the temperature and the humidity. In the multiple-type air conditioning device, the necessary amount of refrigerant varies also with the number of indoor units in operation in addition to the above-described conditions. An appropriate amount of refrigerant needs to be supplied to each indoor unit in operation, but when the supply is not correct, the amount of refrigerant becomes excessive or insufficient, which potentially leads to performance degradation of the indoor unit in operation.
Typically, to deal with the varying necessary amount of refrigerant, refrigerant is accumulated in a receiver when the amount of refrigerant is excessive. When the amount of refrigerant is insufficient, the refrigerant is collected from the receiver to achieve refrigerant adjustment.
Studies have been made to deal with the variation of the necessary amount of refrigerant by performing control using a control device. For example, the Publication of Japanese Patent No. 4071388 discloses that an expansion valve on a stop load side is gradually closed at steps of several pulses, and when evaporation temperature (pipe temperature of a heat source side heat exchanger) has abruptly decreased, the expansion valve is corrected to an opening degree at a step one or two steps before the decrease.

BRIEF SUMMARY OF THE INVENTION

In the invention disclosed in the above-described Publication of Japanese Patent No. 4071388 , refrigerant distribution of the entire circuit is adjusted by the opening degree of the expansion valve on the stop load side. Since the adjustment is performed by the unit of several pulses, the adjustment has limitations. When the expansion valve on the stop load side is opened too much, indoor environment including the stop load is potentially affected.
When the amount of refrigerant is adjusted through accumulation in the receiver as described above, the volume of the receiver needs to be set in accordance with the variation of the amount of refrigerant. The problem is solved by increasing the volume of the receiver. However, the size of an outdoor unit is restricted. When the volume of the receiver is increased, cost increase is caused by, for example, redesigning of the outdoor unit and increase of the size of the outdoor unit.
The present invention is intended to solve the above-described problem by providing a control device of a multiple-type air conditioning device configured to perform control to adjust refrigerant when a necessary amount of refrigerant varies, the multiple-type air conditioning device, a method of controlling the multiple-type air conditioning device, and a computer program of controlling the multiple-type air conditioning device.
To solve the above-described problem, a control device of a multiple-type air conditioning device, the multiple-type air conditioning device, a method of controlling the multiple-type air conditioning device, and a computer program of controlling the multiple-type air conditioning device according to the present invention employ the following means.
A control device of a multiple-type air conditioning device according to a first aspect of the present invention is a control device of a multiple-type air conditioning device including at least one outdoor unit, and a plurality of indoor units each including an indoor electronic expansion valve. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. At heating, when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive, control is performed to close the indoor electronic expansion valves of all stop indoor units.
The present aspect provides a control device of a multiple-type air conditioning device including at least one outdoor unit, and a plurality of indoor units each including an indoor electronic expansion valve. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. At heating, when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive, control is performed to close the indoor electronic expansion valves of all stop indoor units. When the amount of refrigerant at the operation indoor unit becomes excessive and performance degradation is sensed, the indoor electronic expansion valves of all stop indoor units are closed and refrigerant is accumulated in the indoor heat exchangers of the stop indoor units.
When the amount of refrigerant tends to be excessive, refrigerant is accumulated in a receiver of the outdoor unit. When the amount of refrigerant becomes further excessive beyond the accumulation capacity of the receiver, the amount of refrigerant becomes excessive at each operation indoor unit, which leads to performance degradation. Whether the amount of refrigerant has become excessive can be sensed based on whether the difference between the exit temperature and the central-part temperature of the indoor heat exchanger included in each heating operation indoor unit has become equal to or smaller than the first temperature difference. This is possible because the receiver is overfilled so that the amount of refrigerant has become excessive, and refrigerant is accumulated in the indoor heat exchanger of the operation indoor unit so that the exit temperature and the central-part temperature have become substantially equal to each other.
The indoor electronic expansion valve of each stop indoor unit is typically slightly opened to avoid refrigerant accumulation so that the amount of refrigerant is prevented from becoming insufficient. When the difference between the exit temperature and the central-part temperature of the indoor heat exchanger included in each heating operation indoor unit has become equal to or smaller than the first temperature difference, the control device performs control to close the indoor electronic expansion valves of all stop indoor units. Accordingly, refrigerant is accumulated in the indoor heat exchangers of all stop indoor units, and thus an appropriate amount of refrigerant is supplied to the operation indoor unit, thereby preventing performance degradation. In addition, the amount of refrigerant can be adjusted by controlling the electronic expansion valves, and thus the capacity of the receiver of the outdoor unit does not need be increased, which leads to cost reduction.
At installation of the multiple-type air conditioning device, the charge amount of refrigerant is determined based on the number of indoor units and the length of the refrigerant pipe. According to the present aspect, the amount of refrigerant can be adjusting by controlling the electronic expansion valves, and thus the present invention is applicable to a case in which the charge amount is set to be larger than an appropriate amount.
In the above-described first aspect, the outdoor unit may include an outdoor electronic expansion valve, and when the opening degree of the outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control may be performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units.
According to the present aspect, when the opening degree of the outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units. Thus, when the indoor electronic expansion valve of the stop indoor unit is closed so that refrigerant is accumulated in the indoor heat exchanger, and as a result, the amount of refrigerant at the operation indoor unit becomes insufficient and performance degradation is sensed, control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units to collect the refrigerant accumulated in the indoor heat exchanger. Accordingly, the amount of refrigerant at the operation indoor unit can be corrected. In addition, through repetition of the correction, an appropriate amount of refrigerant is supplied to the operation indoor unit, thereby achieving reliable operation of the multiple-type air conditioning device.
When a correct amount of refrigerant is supplied to each operation indoor unit, the electronic expansion valve of the evaporator, in other words, the outdoor electronic expansion valve of the outdoor unit is set to a predetermined opening degree. When the amount of refrigerant of the operation indoor unit becomes insufficient, a larger amount of refrigerant needs to be circulated, and thus the opening degree of the outdoor electronic expansion valve of the outdoor unit is set to be equal to or higher than the predetermined opening degree. The predetermined opening degree is, for example, the maximum opening degree of the outdoor electronic expansion valve. Since the amount of refrigerant is sensed to be insufficient when the outdoor electronic expansion valve is set to be equal to or higher than the predetermined opening degree, the amount of refrigerant at the operation indoor unit can be sensed to be insufficient by a simple method.
A control device of a multiple-type air conditioning device according to a second aspect of the present invention is a control device of a multiple-type air conditioning device including at least one outdoor unit, a plurality of indoor units each including an indoor electronic expansion valve, and a plurality of distribution controllers corresponding to the respective indoor units. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. When the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive, at heating, control is performed to close the indoor electronic expansion valves of all stop indoor units, or at cooling, control is performed to switch four-way switching valves of the distribution controllers corresponding to all stop indoor units and close the indoor electronic expansion valves of all stop indoor units.
The present aspect provides a control device of a multiple-type air conditioning device including at least one outdoor unit, a plurality of indoor units each including an indoor electronic expansion valve, and a plurality of distribution controllers corresponding to the respective indoor units. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. When the difference between the exit temperature and the central-part temperature of the indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than the first temperature difference and the amount of refrigerant is sensed to be excessive, at heating, control is performed to close indoor electronic expansion valves of all stop indoor units. In the multiple-type air conditioning device of a cooling and heating simultaneous type, when the amount of refrigerant at each operation indoor unit becomes excessive and performance degradation is sensed, at heating, the indoor electronic expansion valves of all stop indoor units are closed and refrigerant is accumulated in the indoor heat exchangers of the stop indoor units.
When the amount of refrigerant has become excessive, refrigerant is accumulated in the receiver of the outdoor unit. When the amount of refrigerant becomes excessive beyond the accumulation capacity of the receiver, the amount of refrigerant at each operation indoor unit becomes excessive, which leads to performance degradation. Whether the amount of refrigerant has become excessive can be sensed based on whether the difference between the exit temperature and the central-part temperature of the indoor heat exchanger included in each heating operation indoor unit has become equal to or smaller than the first temperature difference. This is possible because the receiver is overfilled so that the amount of refrigerant has become excessive, and refrigerant is accumulated in the indoor heat exchanger of each heating operation indoor unit so that the exit temperature and the central-part temperature have become substantially equal to each other.
At heating, the indoor electronic expansion valve of each stop indoor unit is typically slightly opened to avoid refrigerant accumulation so that the amount of refrigerant is prevented from becoming insufficient. When the amount of refrigerant is sensed to be excessive, the control device performs control to close the indoor electronic expansion valves of all stop indoor units. Accordingly, refrigerant is accumulated in the indoor heat exchangers of all stop indoor units, and thus an appropriate amount of refrigerant is supplied to the operation indoor unit, thereby preventing performance degradation. The amount of refrigerant can be adjusted by controlling the electronic expansion valves, and thus the capacity of the receiver of the outdoor unit does not need be increased, which leads to cost reduction. At installation of the multiple-type air conditioning device, the charge amount of refrigerant is determined based on the number of indoor units and the length of the refrigerant pipe. According to the present aspect, the amount of refrigerant can be adjusting by controlling the electronic expansion valves, and thus the present invention is applicable to a case in which the charge amount is set to be larger than an appropriate amount.
At cooling, control is performed to switch the four-way switching valves of the distribution controllers corresponding to all stop indoor units and close the indoor electronic expansion valves of all stop indoor units. At cooling, when the amount of refrigerant is sensed to be excessive, the four-way switching valves of the distribution controllers are switched to close the indoor electronic expansion valves. According to the present aspect, similarly to heating, refrigerant is accumulated in the indoor heat exchangers of the stop indoor units, and thus an appropriate amount of refrigerant can be supplied to each operation indoor unit.
In the above-described second aspect, at heating, when the opening degree of an outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at the operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control may be performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units; and at cooling, when the opening degree of the outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at the operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control may be performed to switch the four-way switching valve of the distribution controller corresponding to any one of the stop indoor units or control may be performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units.
According to the present aspect, at heating, when the opening degree of the outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than the predetermined opening degree and the amount of refrigerant at each operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units. At heating, when the indoor electronic expansion valves of the stop indoor units are closed so that refrigerant is accumulated in the indoor heat exchangers, and as a result, the amount of refrigerant at each operation indoor unit becomes insufficient, and performance degradation is sensed, control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units to collect the refrigerant accumulated in the indoor heat exchangers. Accordingly, the amount of refrigerant at the operation indoor unit can be corrected. In addition, through repetition of the correction, a correct amount of refrigerant is supplied to the operation indoor unit, thereby achieving reliable operation of the multiple-type air conditioning device.
At cooling, when the opening degree of the outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than the predetermined opening degree and the amount of refrigerant at each operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control is performed to switch the four-way switching valve of the distribution controller corresponding to any one of the stop indoor units or control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units. At cooling, when the amount of refrigerant is sensed to be insufficient, refrigerant accumulated in the indoor heat exchangers is collected, similarly to heating, by switching the four-way switching valve of any one of the distribution controllers or by slightly opening the indoor electronic expansion valve of any one of the stop indoor units, similarly to heating, and an appropriate amount of refrigerant can be supplied to each operation indoor unit.
In heating operation, when a correct amount of refrigerant is supplied to each operation indoor unit, the electronic expansion valve of the evaporator, in other words, the outdoor electronic expansion valve of the outdoor unit, or the indoor electronic expansion valve of each indoor unit is set to a predetermined opening degree. When the amount of refrigerant at the operation indoor unit becomes insufficient, a larger amount of refrigerant needs to be circulated. The opening degree of the outdoor electronic expansion valve of the outdoor unit or the indoor electronic expansion valve of each indoor unit is set to be equal to or higher than the predetermined opening degree. The predetermined opening degree is, for example, the maximum opening degree of the outdoor electronic expansion valve. Since the amount of refrigerant is sensed to be insufficient when the opening degree of the outdoor electronic expansion valve becomes equal to or higher than the predetermined opening degree, the amount of refrigerant at the operation indoor unit can be sensed to be insufficient by a simple method.
In cooling operation, when a correct amount of refrigerant is supplied to each operation indoor unit, the electronic expansion valve of the evaporator, in other words, the indoor electronic expansion valve of the operation indoor unit is set to a predetermined opening degree. When the amount of refrigerant at the operation indoor unit becomes insufficient, a larger amount of refrigerant needs to be circulated. The opening degree of the indoor electronic expansion valve of the operation indoor unit is set to be equal to or higher than the predetermined opening degree. The predetermined opening degree is, for example, the maximum opening degree of the indoor electronic expansion valve. Since the amount of refrigerant is sensed to be insufficient when the opening degree of the indoor electronic expansion valve becomes equal to or higher than the predetermined opening degree, the amount of refrigerant at the operation indoor unit can be sensed to be insufficient by a simple method.
In each of the above-described aspects, the opening degree of the indoor electronic expansion valve of the stop indoor unit when slightly opened may be an opening degree at which the refrigerant flow rate of the indoor electronic expansion valve is 10 to 20 kg/h.
According to the present aspect, the opening degree of the indoor electronic expansion valve of each stop indoor unit when slightly opened is an opening degree at which the refrigerant flow rate of the indoor electronic expansion valve is 10 to 20 kg/h. This prevents change of indoor environment in which the stop indoor unit is installed due to a large opening degree of the indoor electronic expansion valve and refrigerant accumulation in the indoor heat exchanger of the stop indoor unit due to a small opening degree of the indoor electronic expansion valve, thereby achieving an appropriate opening degree.
In each of the above-described aspects, the amount of refrigerant at each operation indoor unit may be sensed to be excessive when the difference between each of set temperatures of one or more of the operation indoor units and an indoor temperature is continuously equal to or larger than a second temperature difference for a time equal to or longer than a predetermined time and the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit is equal to or smaller than a first temperature difference.
According to the present aspect, the amount of refrigerant at each operation indoor unit is sensed to be excessive when the difference between each of the set temperatures of one or more of the operation indoor units and the indoor temperature is continuously equal to or larger than the second temperature difference for a time equal to or longer than a predetermined time and the difference between the exit temperature and the central-part temperature of the indoor heat exchanger included in each heating operation indoor unit is equal to or smaller than the first temperature difference. When the difference between the set temperature of each operation indoor unit and the indoor temperature is equal to or larger than the second temperature difference, the difference between a temperature set by a user through an indoor controller or the like and the actual indoor temperature is large. When this state continues for a time equal to or longer than the predetermined time, the multiple-type air conditioning device is in a non-heating state in a case of heating or in a non-cooling state in a case of cooling.
When the difference between the exit temperature and the central-part temperature of the indoor heat exchanger included in each heating operation indoor unit is equal to or smaller than the first temperature difference, the receiver is overfilled so that the amount of refrigerant has become excessive, and refrigerant is accumulated in the indoor heat exchanger of the heating operation indoor unit so that the exit temperature and the central-part temperature have become substantially equal to each other.
Thus, the amount of refrigerant at each operation indoor unit is sensed to be excessive when the operation indoor unit is in a non-heating state and the amount of refrigerant is excessive. Accordingly, frequent setting change is not performed, and unnecessary control can be prevented.
A multiple-type air conditioning device according to a third aspect of the present invention includes the above-described control device, at least one outdoor unit, and a plurality of indoor units each including an indoor electronic expansion valve.
A method of controlling a multiple-type air conditioning device according to a fourth aspect of the present invention is a method of controlling a multiple-type air conditioning device including at least one outdoor unit, and a plurality of indoor units each including an indoor electronic expansion valve. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. The method includes a process of closing the indoor electronic expansion valves of all stop indoor units when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference at heating and the amount of refrigerant is sensed to be excessive.
A computer program of controlling a multiple-type air conditioning device according to a fifth aspect of the present invention is a computer program of controlling a multiple-type air conditioning device including at least one outdoor unit, and a plurality of indoor units each including an indoor electronic expansion valve. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. The computer program includes a step of closing the indoor electronic expansion valves of all stop indoor units when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference at heating and the amount of refrigerant is sensed to be excessive.
A method of controlling a multiple-type air conditioning device according to a sixth aspect of the present invention is a method of controlling a multiple-type air conditioning device including at least one outdoor unit, a plurality of indoor units each including an indoor electronic expansion valve, and a plurality of distribution controllers corresponding to the respective indoor units. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. The method includes, when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive, a process of closing the indoor electronic expansion valves of all stop indoor units at heating, and a process of switching four-way switching valves of the distribution controllers corresponding to all stop indoor units and closing the indoor electronic expansion valves of all stop indoor units at cooling.
A computer program of controlling a multiple-type air conditioning device according to a seventh aspect of the present invention is a computer program of controlling a multiple-type air conditioning device including at least one outdoor unit, a plurality of indoor units each including an indoor electronic expansion valve, and a plurality of distribution controllers corresponding to the respective indoor units. Each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit. The computer program includes, when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive, a step of closing the indoor electronic expansion valves of all stop indoor units at heating, and a step of switching four-way switching valves of the distribution controllers corresponding to all stop indoor units and closing the indoor electronic expansion valves of all stop indoor units at cooling.
According to the present invention, a correct amount of refrigerant is achieved by controlling an indoor electronic expansion valve, and thus performance degradation of an indoor unit can be prevented by simple control.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic configuration diagram illustrating a multiple-type air conditioning device according to a first embodiment of the present invention;
FIG. 2 is a flowchart illustrating control of the multiple-type air conditioning device according to the first embodiment of the present invention when the amount of refrigerant varies in heating operation;
FIG. 3 is a schematic diagram illustrating an indoor heat exchanger of the multiple-type air conditioning device according to the first embodiment of the present invention;
FIG. 4 is a graph illustrating the relation between the opening degree and flow rate of an indoor electronic expansion valve of the multiple-type air conditioning device according to the first embodiment of the present invention;
FIG. 5 is a diagram illustrating the operation state of an indoor unit of the multiple-type air conditioning device according to the first embodiment of the present invention in heating operation; and
FIG. 6 is a schematic configuration diagram illustrating a multiple-type air conditioning device according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following describes a control device of a multiple-type air conditioning device, the multiple-type air conditioning device, a method of controlling the multiple-type air conditioning device, and a computer program of controlling the multiple-type air conditioning device according to an embodiment of the present invention with reference to the accompanying drawings.

[First embodiment]

The following describes a first embodiment of the present invention with reference to FIGS. 1 to 5.
FIG. 1 illustrates a schematic configuration diagram of a multiple-type air conditioning device according to the present embodiment.
In a multiple-type air conditioning device 1, one outdoor unit 2 is connected in parallel with a plurality of indoor units 3A, 3B, and 3C. The multiple-type air conditioning device according to the present embodiment is of a cooling and heating switching type. The plurality of indoor units 3A, 3B, and 3C are connected in parallel with each other through a gas-side pipe 4 and a liquid-side pipe 5 each connected with the outdoor unit 2 with a bifurcation device 6 interposed therebetween.
The outdoor unit 2 includes an inverter-driven compressor 10 configured to compress refrigerant, an outdoor-side four-way switching valve 12 configured to switch the circulation direction of refrigerant, a plurality of outdoor heat exchangers (heat exchangers) 13 configured to exchange heat between refrigerant and external air, a supercooling coil 14 integrated with each outdoor heat exchanger 13, an outdoor electronic expansion valve (EEVH) 15, a receiver 16 configured to accumulate liquid refrigerant, a supercooling heat exchanger 17 configured to supercool liquid refrigerant, a supercooling expansion valve (EEVSC) 18 configured to control the amount of refrigerant bifurcated to the supercooling heat exchanger 17, an accumulator 19 configured to separate a liquid component from refrigerant gas to be taken into the compressor 10 and cause only a gas component to be taken into the compressor 10, a gas-side operation valve 20, and a liquid-side operation valve 21.
The above-described instruments of the outdoor unit 2 are sequentially connected with each other through a refrigerant pipe 22 to form a well-known outdoor-side refrigerant circuit 23. The outdoor unit 2 also includes an outdoor fan (not illustrated) configured to send external air to the outdoor heat exchangers 13.
The gas-side pipe 4 and the liquid-side pipe 5 are refrigerant pipes connected with the gas-side operation valve 20 and the liquid-side operation valve 21 of the outdoor unit 2. The pipe lengths of the gas-side pipe 4 and the liquid-side pipe 5 are set as appropriate in accordance with the distance between the outdoor unit 2 and each of the plurality of indoor units 3A, 3B, and 3C connected with the outdoor unit 2 at on-site installation. The bifurcation devices 6 are provided halfway through the gas-side pipe 4 and the liquid-side pipe 5, and an optional number of the indoor units 3A, 3B, and 3C are connected with the pipes through the bifurcation devices 6. This configuration forms a closed refrigeration cycle (refrigerant circuit) 7.
Each of the indoor units 3A, 3B, and 3C includes an indoor heat exchanger 30 configured to condition indoor air by cooling or heating refrigerant through heat exchange with indoor air, an indoor electronic expansion valve (EEVC) (electronic expansion valve) 31, an indoor fan (not illustrated) configured to circulate indoor air through the indoor heat exchanger 30, and an indoor controller (not illustrated), and is connected with the bifurcation device 6.
The indoor electronic expansion valve 31 is set to a predetermined stop opening degree when the corresponding indoor unit 3 is stopped in normal operation. The predetermined stop opening degree in cooling operation corresponds to a fully closed state, and the predetermined stop opening degree in heating operation corresponds to a slightly opened state close to the fully closed state.
Although FIG. 1 illustrates the example in which the three indoor units 3A, 3B, and 3C are installed, the number of installed indoor units may be optionally determined.
In the following description, each indoor unit 3 is denoted by any one of A, B, and C at the end when the indoor unit 3 is distinguished, or A, B, and C are omitted when each indoor unit 3 is not distinguished.
Each indoor unit 3 in operation is referred to as an operation indoor unit 3, each operation indoor unit 3 in heating operation is referred to as a heating operation indoor unit 3, and each indoor unit 3 at a stop is referred to as a stop indoor unit 3.
A control device 70 acquires, for example, a temperature set by any indoor controller or the like, the indoor temperature, a refrigerant temperature obtained by an exit-part temperature sensor 61 of each indoor heat exchanger 30 to be described later or the like, and performs, for example, control of the opening degree of each indoor electronic expansion valve 31 and switching control of the outdoor-side four-way switching valve 12.
The control device 70 includes, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and a computer-readable storage medium. A series of processing for achieving various kinds of functions is stored, for example, as a computer program in the storage medium or the like. The various kinds of functions are achieved when the CPU reads the computer program onto the RAM or the like and executes information manipulation and arithmetic processing. The computer program may be, for example, installed on a ROM or another storage medium in advance, provided while being stored in a computer-readable storage medium, or distributed through a wired or wireless communication means. The computer-readable storage medium is, for example, a magnetic disk, a magneto optical disc, a CD-ROM, a DVD-ROM, or a semiconductor memory.
The control device 70 includes a sensing unit 71 and a control unit 72.
The sensing unit 71 senses whether the amount of refrigerant is excessive or insufficient based on a value acquired by the control device 70.
The control unit 72 controls each instrument of the multiple-type air conditioning device 1 to set an appropriate amount of refrigerant based on information of whether the amount of refrigerant is excessive or insufficient, which is sensed by the sensing unit 71.
In the above-described multiple-type air conditioning device 1, cooling operation is performed as described below.
High-temperature and high-pressure refrigerant gas compressed at and discharged from the compressor 10 is circulated to the outdoor heat exchangers 13 through the outdoor-side four-way switching valve 12 and condensed into liquid through heat exchange with external air sent by the outdoor fan at the outdoor heat exchangers 13. This liquid refrigerant is further cooled through the supercooling coils 14, then passes through the outdoor electronic expansion valves 15, and is temporarily accumulated in the receiver 16.
The liquid refrigerant, the circulation amount of which is adjusted at the receiver 16 is partially bifurcated from a liquid refrigerant pipe while being circulated on a liquid refrigerant pipe side through the supercooling heat exchanger 17, and is provided with a supercooling degree through heat exchange with refrigerant adiabatically expanded through the supercooling expansion valve 18. This liquid refrigerant is guided from the outdoor unit 2 to the liquid-side pipe 5 through the liquid-side operation valve 21 and bifurcated to the indoor units 3A, 3B, and 3C through the bifurcation device 6.
The bifurcated liquid refrigerant flows into each of the indoor units 3A, 3B, and 3C, is adiabatically expanded to gas-liquid two-phase flow through the indoor electronic expansion valve 31, and flows into the indoor heat exchanger 30. At each indoor heat exchanger 30, the refrigerant exchanges heat with indoor air circulated by the indoor fan (not illustrated), and the indoor air is cooled and used for indoor cooling. The refrigerant is converted into gas, reaches the bifurcation device 6, and is joined with refrigerant gas from the other indoor units at the gas-side pipe 4.
The refrigerant gas joined at the gas-side pipe 4 returns to the outdoor unit 2, passes through the gas-side operation valve 20 and the outdoor-side four-way switching valve 12, joins refrigerant gas from the supercooling heat exchanger 17, and then is introduced into the accumulator 19. A liquid component of the refrigerant gas is separated at the accumulator 19, and only a gas component is taken into the compressor 10. This refrigerant is compressed at the compressor 10 again and subjected to repetition of the above-described cycle, thereby performing cooling operation.
Heating operation is performed as described below.
High-temperature and high-pressure refrigerant gas compressed at and discharged from the compressor 10 is circulated to the gas-side operation valve 20 through the outdoor-side four-way switching valve 12. This high-pressure gas refrigerant is discharged from the outdoor unit 2 through the gas-side operation valve 20 and the gas-side pipe 4, and introduced to the plurality of indoor units 3A, 3B, and 3C through the bifurcation device 6.
Having been introduced to the indoor units 3A, 3B, and 3C, the high-temperature and high-pressure refrigerant gas exchanges heat with indoor air circulated through the indoor fan (not illustrated) at each indoor heat exchanger 30, and the indoor air thus heated is blown out to indoor and used for heating. Refrigerant condensed to liquid at each indoor heat exchanger 30 reaches the bifurcation device 6 through the indoor electronic expansion valve 31, joins refrigerant from the other indoor units, and returns to the outdoor unit 2 through the liquid-side pipe 5. At heating, in each of the indoor units 3A, 3B, and 3C, the opening degree of the indoor electronic expansion valve 31 is controlled so that the refrigerant exit temperature or refrigerant supercooling degree of the indoor heat exchanger 30 functioning as a condenser becomes equal to a control target value.
The refrigerant returned to the outdoor unit 2 reaches the supercooling heat exchanger 17 through the liquid-side operation valve 21, and thereafter flows into and temporarily accumulated in the receiver 16 so that the circulation amount of the refrigerant is adjusted. This liquid refrigerant is supplied to the outdoor electronic expansion valve 15 and adiabatically expanded, and then flows into the outdoor heat exchangers 13.
At each outdoor heat exchanger 13, refrigerant exchanges heat with external air sent from the outdoor fan and absorbs heat from the external air to evaporate into gas. This refrigerant is introduced to the accumulator 19 from the outdoor heat exchangers 13 through the outdoor-side four-way switching valve 12. At the accumulator 19, a liquid component of the refrigerant gas is separated and only gas component is taken into the compressor 10 and compressed at the compressor 10 again. The above-described cycle is repeated, thereby performing heating operation.
FIG. 2 is a flowchart illustrating control of the multiple-type air conditioning device according to the present embodiment when the amount of refrigerant varies in heating operation.
In the multiple-type air conditioning device 1, a necessary amount of refrigerant varies with various factors such as air conditions and the number of indoor units in operation. Thus, it is sensed whether the amount of refrigerant tends to be excessive or insufficient, and control is performed so that an appropriate amount of refrigerant circulates in accordance with variation of the necessary amount of refrigerant.
First, as illustrated at step S201 in FIG. 2, the sensing unit 71 determines whether the amount of circulating refrigerant tends to be excessive. Whether the amount of refrigerant is excessive is determined based on the temperature difference between temperatures at an exit part and a central part of the indoor heat exchanger 30 of each operation indoor unit 3.
FIG. 3 is a schematic diagram of each indoor heat exchanger of the multiple-type air conditioning device according to the present embodiment.
As illustrated in FIG. 3, in heating operation, refrigerant circulates through the indoor heat exchanger 30 of each heating operation indoor unit 3 in a direction indicated with the arrow in FIG. 3. The indoor heat exchanger 30 of the heating operation indoor unit 3 is provided with, sequentially from the refrigerant exit side in heating operation, the exit-part temperature sensor 61, a central-part temperature sensor 62, and an entrance-part temperature sensor 63. The exit-part temperature sensor 61 measures an exit temperature T1, the central-part temperature sensor 62 measures a central-part temperature T2, and the entrance-part temperature sensor 63 measures an entrance temperature T3.
When an appropriate amount of refrigerant is circulating, high-temperature and high-pressure refrigerant gas flows in through an entrance part of the indoor heat exchanger 30 (on the entrance-part temperature sensor 63 side) and is condensed to liquid through heat exchange with indoor air. Thus, the temperatures have the relation of T1 < T2 < T3.
When the amount of refrigerant is excessive, the receiver 16 is overfilled, and refrigerant is accumulated in the indoor heat exchanger 30 of the heating operation indoor unit 3. The exit temperature T1 and the central-part temperature T2 are substantially equal to each other, and thus the temperatures have the relation of T1 ≈ T2 < T3. The sensing unit 71 senses that the amount of refrigerant tends to be excessive when the temperature difference |T1 - T2| between the exit temperature T1 and the central-part temperature T2 becomes equal to or smaller than a first temperature difference. The first temperature difference is, for example, 5 deg.
At step S201 in FIG. 2, the control device 70 determines whether the temperature difference |T1 - T2| between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 of the heating operation indoor unit 3 is equal to or smaller than the first temperature difference. When the temperature difference |T1 - T2| is equal to or smaller than the first temperature difference, the process transitions to step S202. When the temperature difference |T1 - T2| is larger than the first temperature difference, the determination at step S201 is performed again.
When the temperature difference |T1 - T2| between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 of the heating operation indoor unit 3 is equal to or smaller than the first temperature difference, in other words, when the amount of refrigerant is sensed to be excessive at step S201, the control unit 72 fully closes the indoor electronic expansion valves 31 of all stop indoor units 3 (S202).
Normally, the indoor electronic expansion valve 31 of each stop indoor unit 3 is slightly opened so that refrigerant is not stored to avoid refrigerant insufficiency. When the indoor electronic expansion valves 31 of all stop indoor units 3 are fully closed at step S202, refrigerant circulating through the stop indoor units 3 is accumulated in the indoor heat exchangers 30. In this manner, refrigerant in an amount that tends to be excessive is collected by the indoor heat exchangers 30 of the stop indoor units 3.
FIG. 4 is a graph illustrating the relation between the opening degree and flow rate of each indoor electronic expansion valve of the multiple-type air conditioning device according to the present embodiment.
In FIG. 4, the vertical axis represents the flow rate, and the horizontal axis represents the expansion valve opening degree.
When each indoor unit 3 is slightly opened, the opening degree is sufficiently small relative to the maximum opening degree of the valve, and is larger than an opening degree at which refrigerant is accumulated in the indoor unit 3 and smaller than an opening degree at which indoor environment is changed due to refrigerant circulation.
When the maximum opening degree of the indoor electronic expansion valve 31 according to the present embodiment is denoted by D, the flow rate in this case is F as illustrated in FIG. 4. When a flow rate necessary for slightly opening the indoor electronic expansion valve 31 is denoted by a, the expansion valve opening degree in this case is da as illustrated in FIG. 4.
For example, when the refrigerant flow rate is 50 kg/h when the opening degree of the indoor electronic expansion valve 31 is at maximum, the opening degree of the indoor electronic expansion valve 31 of the stop indoor unit 3 when slightly opened may be an opening degree at which the refrigerant flow rate is 10 to 20 kg/h.
Subsequently at step S203, the sensing unit 71 determines whether the amount of circulating refrigerant tends to be insufficient. Whether the amount of refrigerant is insufficient is determined based on the opening degree of the expansion valve of an evaporator (in the present embodiment, the outdoor heat exchanger 13).
Normally, when a correct amount of refrigerant is supplied to the operation indoor unit 3, the electronic expansion valve of the evaporator, in other words, the outdoor electronic expansion valve 15 of the outdoor unit 2 is set to a predetermined opening degree (for example, 100 to 200 pulses). However, when an insufficient amount of refrigerant is supplied to the operation indoor unit 3, a larger amount of refrigerant needs to be circulated, and thus the opening degree of the outdoor electronic expansion valve 15 of the outdoor unit 2 is set to be equal to or higher than the predetermined opening degree. The predetermined opening degree is, for example, the maximum opening degree of the outdoor electronic expansion valve 15. Thus, it can be sensed that the amount of refrigerant tends to be insufficient based on the opening degree of the outdoor electronic expansion valve 15.
At step S203, the control device 70 determines whether the opening degree of the outdoor electronic expansion valve 15 of each outdoor heat exchanger 13 of the outdoor unit 2 is equal to the maximum opening degree. When the opening degree of the outdoor electronic expansion valve 15 is equal to the maximum opening degree, the process transitions to step S204. When the opening degree of the outdoor electronic expansion valve 15 is smaller than the maximum opening degree, the process transitions to step S206.
When it is sensed by the sensing unit 71 at step S203 that the opening degree of the outdoor electronic expansion valve 15 of each outdoor heat exchanger 13 of the outdoor unit 2 is equal to the maximum opening degree, in other words, the amount of refrigerant is insufficient, the control unit 72 slightly opens the fully closed indoor electronic expansion valve 31 of any one of the stop indoor units 3 (S204).
When the indoor electronic expansion valve 31 of each stop indoor unit 3 is fully closed and refrigerant is accumulated in the indoor heat exchanger 30, the amount of refrigerant that tends to be excessive decreases. When the amount of refrigerant of each operation indoor unit 3 becomes insufficient and performance degradation is sensed by the sensing unit 71, the control unit 72 performs control to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3 to collect the refrigerant accumulated in the indoor heat exchangers 30.
At step S205, the sensing unit 71 determines whether the operation has become stable. Specifically, the sensing unit 71 determines whether the amount of refrigerant does not tend to be excessive nor tend to be insufficient. When the amount of refrigerant does not tend to be excessive nor tend to be insufficient, the sensing unit 71 determines that the operation has become stable. When it is determined by the sensing unit 71 that the operation has become stable, the process transitions to step S206. When it is determined by the sensing unit 71 that the operation has not become stable, the process returns to step S204.
When it is determined at step S205 that the operation has become stable or when it is determined at step S203 that the amount of refrigerant does not tend to be insufficient, the operation is continued (S206). Thereafter, the control illustrated in this flowchart is repeated.
The above-described control at steps S203 to S205 is correction control performed to avoid frequent repetition between excessive and insufficient amounts of refrigerant, in other words, frequent repetition between the fully closed and slightly opened states of the indoor electronic expansion valve 31 of any stop indoor unit 3.
FIG. 5 is a diagram illustrating the operation state of each indoor unit of the multiple-type air conditioning device according to the present embodiment in heating operation.
In the diagram illustrated in FIG. 5, the indoor units 3 are five indoor units 3A to 3E. In the diagram, "operational" indicates a normal operation (heating operation), "slightly opened" indicates that the corresponding indoor unit 3 is at a stop and the indoor electronic expansion valve 31 is slightly opened, "stopped" indicates that the corresponding indoor unit 3 is at a stop and the indoor electronic expansion valve 31 is fully closed, "performance degradation (excessive)" indicates that the corresponding indoor unit 3 is operational and the performance has degraded due to an excessive amount of refrigerant, and "performance degradation (insufficient)" indicates that the corresponding indoor unit 3 is operational and the performance has degraded due to an insufficient amount of refrigerant. In addition, an upward arrow indicates that the corresponding indoor unit 3 is in a state same as that of the above column.
At step S1, the indoor units 3A and 3B are operation indoor units 3, the indoor units 3C, 3D, and 3E are stop indoor units 3, and the indoor units 3C, 3D, and 3E are "slightly opened". Accordingly, the indoor electronic expansion valves 31 of the stop indoor units 3C, 3D, and 3E are slightly opened.
Subsequently at step S2, the indoor unit 3B becomes the state of "performance degradation (excessive)". Accordingly, the sensing unit 71 of the control device 70 senses the amount of refrigerant to be excessive, and the control unit 72 performs control to fully close the indoor electronic expansion valves 31 of all stop indoor units 3C, 3D and 3E (S3).
At step S3, the indoor units 3C, 3D, and 3E become the state of "stopped". Specifically, the indoor electronic expansion valves 31 of the stop indoor units 3C, 3D, and 3E are fully closed. Accordingly, refrigerant is accumulated in the indoor heat exchangers 30 of the stop indoor units 3C, 3D, and 3E.
At step S4, since refrigerant in an excessive amount is accumulated in the indoor heat exchangers 30 of the stop indoor units 3C, 3D, and 3E, the excessiveness of the amount of refrigerant at the operation indoor unit 3B is solved, and the operation indoor unit 3B becomes the state of "operational". In this state, the indoor electronic expansion valves 31 of the stop indoor units 3C, 3D, and 3E remain fully closed, and refrigerant is continuously accumulated in the indoor heat exchangers 30 of the stop indoor units 3C, 3D, and 3E.
At step S5 since refrigerant is continuously accumulated in the indoor heat exchangers 30 of the stop indoor units 3C, 3D, and 3E, the operation indoor unit 3B becomes the state of "performance degradation (insufficient)". Accordingly, the sensing unit 71 of the control device 70 senses the amount of refrigerant to be insufficient, and the control unit 72 performs control to slightly open any one of the stop indoor units 3, in this case, the stop indoor unit 3E being fully closed (S6).
At step S6, the indoor unit 3E becomes the state of "slightly opened". Specifically, the indoor electronic expansion valve 31 of the stop indoor unit 3E is slightly opened. Accordingly, refrigerant accumulated in the indoor heat exchanger 30 of the stop indoor unit 3E is collected, and the amount of circulating refrigerant increases.
At step S7, since refrigerant in an insufficient amount is collected from the indoor heat exchanger 30 of the stop indoor unit 3E, the insufficiency of the amount of refrigerant at the operation indoor unit 3B is solved, and the operation indoor unit 3B becomes the state of "operational". In this state, the indoor electronic expansion valves 31 of the stop indoor units 3C and 3D remain fully closed, and refrigerant is continuously accumulated in the indoor heat exchangers 30 of the stop indoor units 3C and 3D.
As described above, control is performed to fully close the indoor electronic expansion valves 31 of all stop indoor units 3 when the amount of refrigerant is excessive, and control is performed to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3 when the amount of refrigerant is insufficient.
To avoid frequent repetition of these controls, the correction at the above-described steps S2 to S6 is performed to determine the opening state of each indoor electronic expansion valve 31 in which a necessary amount of refrigerant circulates.
In the present embodiment, at step S201 in FIG. 2, the amount of refrigerant is sensed to be excessive based on the temperature difference, but an additional condition may be provided.
For example, the amount of refrigerant at each operation indoor unit 3 may be sensed to be excessive when the difference between the set temperature of the operation indoor unit 3 and the indoor temperature is continuously equal to or larger than a second temperature difference for a time equal to or longer than a predetermined time and the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in each heating operation indoor unit 3 is equal to or smaller than the first temperature difference.
When the difference between the set temperature of the operation indoor unit 3 and the indoor temperature is equal to or larger than the second temperature difference, the difference between the set temperature, which is set by a user through the indoor controller or the like, and the actual indoor temperature is large. When this state continues for a time equal to or longer than the predetermined time, the multiple-type air conditioning device 1 is in a non-heating state in a case of heating or a non-cooling state in a case of cooling. Thus, the amount of refrigerant at the operation indoor unit 3 may be sensed to be excessive when the operation indoor unit 3 is in the non-heating state and the amount of refrigerant is excessive. Accordingly, frequent setting change is not performed, and unnecessary control can be prevented. The second temperature difference is, for example, 3 deg, and the predetermined time is, for example, five minutes.
A control device of a multiple-type air conditioning device, the multiple-type air conditioning device, a method of controlling the multiple-type air conditioning device, and a computer program of controlling the multiple-type air conditioning device according to the present embodiment as described above achieve the following effects.
The present embodiment provides the control device 70 of the multiple-type air conditioning device 1 including at least one outdoor unit 2, and a plurality of indoor units 3 each including the indoor electronic expansion valve 31. Each indoor unit 3 in operation is referred to as an operation indoor unit 3, each operation indoor unit 3 in heating operation is referred to as a heating operation indoor unit 3, and each indoor unit 3 at a stop is referred to as a stop indoor unit 3. At heating, when the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in each heating operation indoor unit 3 is equal to or lower than the first temperature difference and the amount of refrigerant is sensed to be excessive, control is performed to close the indoor electronic expansion valves 31 of all stop indoor units 3. When the amount of refrigerant at the operation indoor units 3 becomes excessive and performance degradation is sensed, the indoor electronic expansion valves 31 of all stop indoor units 3 are closed so that refrigerant is accumulated in the indoor heat exchangers 30 of the stop indoor units 3.
When the amount of refrigerant tends to be excessive, refrigerant is accumulated in the receiver 16 of the outdoor unit 2. When the amount of refrigerant becomes further excessive beyond the accumulation capacity of the receiver 16, the amount of refrigerant at the operation indoor units 3 becomes excessive, which leads to performance degradation. Whether the amount of refrigerant has become excessive can be sensed based on whether the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in each heating operation indoor unit 3 has become equal to or smaller than the first temperature difference. This is possible because the receiver 16 is overfilled so that the amount of refrigerant has become excessive, and refrigerant is accumulated in the indoor heat exchanger 30 of each operation indoor unit 3 so that the exit temperature T1 and the central-part temperature T2 has become substantially equal to each other.
The indoor electronic expansion valve 31 of each stop indoor unit 3 is typically slightly opened to avoid refrigerant accumulation so that the amount of refrigerant is prevented from becoming insufficient. When the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in each heating operation indoor unit 3 becomes equal to or smaller than the first temperature difference, the control device 70 performs control to close the indoor electronic expansion valves 31 of all stop indoor units 3. Accordingly, refrigerant is accumulated in the indoor heat exchangers 30 of all stop indoor units 3, and an appropriate amount of refrigerant is supplied to each operation indoor unit 3, thereby preventing performance degradation. In addition, since the amount of refrigerant can be adjusted by controlling the indoor electronic expansion valve 31, it is not needed to increase the capacitor of the receiver 16 of the outdoor unit 2, which leads to cost reduction. At installation of the multiple-type air conditioning device 1, the charge amount of refrigerant is determined based on the number of indoor units 3 and the length of the refrigerant pipe. According to the present embodiment, the amount of refrigerant can be adjusted by controlling the indoor electronic expansion valve 31, and thus the present invention is applicable to a case in which the charge amount is set to be larger than an appropriate amount.
According to the present embodiment, when the opening degree of the outdoor electronic expansion valve 15 of the outdoor unit 2 becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit 3 is sensed to be insufficient while the indoor electronic expansion valves 31 of one or more of the stop indoor units 3 are closed, control is performed to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3. Accordingly, when the indoor electronic expansion valves 31 of the stop indoor units 3 are closed so that refrigerant is accumulated in the indoor heat exchangers 30 and the amount of refrigerant at the operation indoor unit 3 becomes insufficient, and thus performance degradation is sensed, control is performed to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3 to collect the refrigerant accumulated in the indoor heat exchangers 30. In this manner, the amount of refrigerant at the operation indoor unit 3 can be corrected. Through repetition of the correction, an appropriate amount of refrigerant is supplied to the operation indoor unit 3, thereby achieving reliable operation of the multiple-type air conditioning device 1.
When a correct amount of refrigerant is supplied to the operation indoor unit 3, the electronic expansion valve of the evaporator, in other words, the outdoor electronic expansion valve 15 of the outdoor unit 2 is set to a predetermined opening degree. When the amount of refrigerant at the operation indoor unit 3 is insufficient, a larger amount of refrigerant needs to be circulated, and thus the opening degree of the outdoor electronic expansion valve 15 of the outdoor unit 2 is set to be equal to or higher than the predetermined opening degree. The predetermined opening degree is, for example, the maximum opening degree of the outdoor electronic expansion valve 15. Since the amount of refrigerant is sensed to be insufficient when the opening degree of the outdoor electronic expansion valve 15 becomes equal to or higher than the predetermined opening degree, the amount of refrigerant at the operation indoor unit 3 can be sensed to be insufficient by a simple method.
According to the present embodiment, the opening degree of the indoor electronic expansion valve 31 of the stop indoor unit 3 when slightly opened is an opening degree at which the refrigerant flow rate of the indoor electronic expansion valve 31 is 10 to 20 kg/h. This prevents change of indoor environment in which the stop indoor unit 3 is installed due to a too large opening degree of the indoor electronic expansion valve 31, and refrigerant accumulation at the indoor heat exchanger 30 of the stop indoor unit 3 due to a too small opening degree of the indoor electronic expansion valve 31, thereby achieving an appropriate opening degree.
According to the present embodiment, when the difference between each of the set temperatures of the one or more operation indoor units 3 and the indoor temperature is continuously equal to or larger than the second temperature difference for a time equal to or longer than a predetermined time and the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in each heating operation indoor unit 3 is equal to or smaller than the first temperature difference, the amount of refrigerant at the operation indoor units 3 is sensed to be excessive. When the difference between the set temperature of each operation indoor unit 3 and the indoor temperature is equal to or larger than the second temperature difference, the difference between a temperature set by the user through the indoor controller or the like and the actual indoor temperature is large. When this state continues for a time equal to or longer than the predetermined time, the multiple-type air conditioning device 1 is in the non-heating state in a case of heating or the non-cooling state in a case of cooling. When the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in the heating operation indoor unit 3 is equal to or smaller than the first temperature difference, the receiver 16 is overfilled so that the amount of refrigerant is excessive, and refrigerant is accumulated in the indoor heat exchanger 30 of the heating operation indoor unit 3 so that the exit temperature T1 and the central-part temperature T2 are substantially equal to each other. Thus, the amount of refrigerant at the operation indoor unit 3 is sensed to be excessive when the operation indoor unit 3 is in the non-heating state and the amount of refrigerant is excessive. Accordingly, frequent setting change is not performed, and unnecessary control can be prevented.

[Second embodiment]

The following describes a second embodiment of the present invention with reference to FIG. 6.
Although the multiple-type air conditioning device according to the above-described first embodiment is of a cooling and heating switching type, a multiple-type air conditioning device according to the present embodiment is of a cooling and heating simultaneous type. Other features are identical to those of the first embodiment, and thus an identical component is denoted by an identical reference sign and description thereof will be omitted.
FIG. 6 illustrates a schematic configuration diagram of the multiple-type air conditioning device according to the present embodiment.
The multiple-type air conditioning device 1 according to the present embodiment is an air conditioning device (also referred to as "cooling and heating simultaneous type" or "cooling and heating free"; hereinafter, also referred to as "cooling and heating simultaneous type") in which simultaneous automatic operation of cooling and heating at a plurality of indoor units is achieved with one outdoor unit.
The multiple-type air conditioning device 1 includes the one outdoor unit 2, the plurality (for example, five) of indoor units 3A, 3B, 3C, 3D, and 3E, a high-pressure gas pipe 4H, a low-pressure gas pipe 4L, and the liquid-side pipe 5 connecting these components, and the control device 70.
The outdoor unit 2 includes, for example, the one compressor 10, two outdoor heat exchangers 13A and 13B, and two outdoor-side four- way switching valves 12A and 12B.
In the following description, when not distinguished, components indicated as, for example, the outdoor heat exchangers 13A and 13B and the outdoor-side four- way switching valves 12A and 12B are indicated as the outdoor heat exchangers 13 and the outdoor-side four-way switching valve 12 with reference signs such as A and B being omitted.
In the present embodiment, the outdoor-side four-way switching valves 12 are provided for the respective outdoor heat exchangers 13, but the present invention is not limited to this configuration. For example, the multiple-type air conditioning device 1 may include three outdoor heat exchangers 13 and two outdoor-side four-way switching valve 12, one of the outdoor-side four-way switching valves 12 may be connected with two of the outdoor heat exchangers 13, and the other outdoor-side four-way switching valve 12 may be connected with the remaining one outdoor heat exchanger 13.
In the present embodiment, the description is made with an exemplary configuration in which four-way switching valves are used, but the present invention is not limited to this configuration. For example, two three-way valves may be used to achieve a function same as that achieved by the four-way switching valves.
In the present embodiment, the description is made with an exemplary configuration in which the multiple-type air conditioning device 1 includes five indoor units 3, but the number of indoor units 3 is not particularly limited.
The outdoor heat exchangers 13 exchange heat with outdoor air, is integrated with the supercooling coil 14, and operates as a condenser or an evaporator in accordance with the state of refrigerant passing therethrough. An outdoor electronic expansion valve (EEVH) 15A or 15B is provided near the outdoor heat exchanger 13A or 13B, respectively, on the refrigerant pipe 22 between each of the outdoor heat exchangers 13A and 13B and the receiver 16.
The compressor 10 is operated in accordance with requested performance. The compressor 10 compresses low-temperature and low-pressure gas refrigerant from the outdoor heat exchangers 13 to produce high-temperature and high-pressure gas refrigerant.
The refrigerant is compressed to high-pressure gas refrigerant by the compressor 10 and discharged to the high-pressure gas pipe 4H.
The high-pressure gas pipe 4H positioned in the outdoor unit 2 bifurcates at a bifurcation point, and the bifurcated pipes are connected with the outdoor-side four- way switching valves 12A and 12B at high-pressure gas pipe ports 12-1. The outdoor-side four- way switching valves 12A and 12B each include an outdoor heat exchanger side port 12-2 connected with the outdoor heat exchanger 13A or 13B, respectively, a low-pressure gas pipe side port 12-3 connected with a low-pressure gas bifurcated pipe joining the low-pressure gas pipe 4L at a bifurcation point on the low-pressure gas pipe 4L, and a bypass pipe side port 12-4 connected with the low-pressure gas bifurcated pipe through a strainer and a capillary tube. The outdoor-side four- way switching valves 12A and 12B switch the outdoor heat exchangers 13 connected therewith to the high-pressure side or the low-pressure side.
The low-pressure gas pipe 4L positioned in the outdoor unit 2 is connected with the compressor 10 through the accumulator 19. Liquid refrigerant collected at the accumulator 19 is returned to the compressor 10 through a liquid refrigerant return line.
The outdoor heat exchangers 13A and 13B are each connected with the refrigerant pipe 22 on a side opposite to a side connected with the outdoor-side four- way switching valve 12A or 12B, respectively. The refrigerant pipe 22 in the outdoor unit 2 is provided with the receiver 16 configured to accumulate liquid refrigerant, and the supercooling heat exchanger 17 configured to supercool refrigerant flowing through the refrigerant pipe 22 in cooling operation. The supercooling heat exchanger 17 takes out part of liquid refrigerant flowing through the refrigerant pipe 22, and supercools the liquid refrigerant flowing through the refrigerant pipe 22 by using refrigerant cooled through expansion and vaporization at the supercooling expansion valve (EEVSC) 18. The gas refrigerant used in the supercooling and vaporized is transferred back to the accumulator 19.
The above-described instruments of the outdoor unit 2 are sequentially connected with each other through the refrigerant pipe 22 to form the well-known the outdoor-side refrigerant circuit 23. The outdoor unit 2 also includes an outdoor fan (not illustrated) configured to send external air to the outdoor heat exchangers 13.
The low-pressure gas pipe 4L, the high-pressure gas pipe 4H, and the liquid-side pipe 5 are refrigerant pipes connected with the gas-side operation valve 20 and the liquid-side operation valve 21 of the outdoor unit 2. The pipe lengths thereof are set as appropriate in accordance with the distance between the outdoor unit 2 and each of the plurality of indoor units 3A, 3B, 3C, 3D, and 3E connected with the outdoor unit 2 at on-site installation. Bifurcation devices (not illustrated) are provided halfway through the low-pressure gas pipe 4L, the high-pressure gas pipe 4H, and the liquid-side pipe 5, and an optional number of indoor units 3A, 3B, 3C, 3D, and 3E are connected with the pipes through the bifurcation devices. This configuration forms the well-known closed refrigeration cycle (refrigerant circuit) 7.
The plurality of provided indoor units 3 have equivalent configurations. Each indoor unit 3 includes the indoor heat exchanger 30 configured to perform heat exchange with indoor air. The indoor electronic expansion valve 31 is provided on a liquid-refrigerant bifurcated pipe connecting the indoor heat exchanger 30 and the liquid-side pipe 5. Each indoor unit 3 is provided with a distribution controller 8 configured to perform switching between the high-pressure gas pipe 4H and the low-pressure gas pipe 4L.
The distribution controller 8 includes an indoor side four-way switching valve 81. The indoor side four-way switching valve 81 includes a high-pressure gas pipe port 81-1 connected with a high-pressure gas bifurcated pipe bifurcated from a main pipe of the high-pressure gas pipe 4H, an indoor heat exchanger side port 81-2 connected with the indoor heat exchanger 30, a low-pressure gas pipe port 81-3 connected with an indoor side low-pressure gas bifurcated pipe bifurcated from a main pipe of the low-pressure gas pipe 4L, and a low-pressure bypass pipe port 81-4 connected with a low-pressure bypass pipe joining the indoor side low-pressure gas bifurcated pipe at a halfway position.
In heating operation, the indoor side four-way switching valve 81 communicates the high-pressure gas pipe port 81-1 and the indoor heat exchanger side port 81-2 and communicates the low-pressure gas pipe port 81-3 and the low-pressure bypass pipe port 81-4. Accordingly, high-pressure gas is supplied to the indoor heat exchanger 30 in heating operation.
In cooling operation, the indoor side four-way switching valve 81 communicates the high-pressure gas pipe port 81-1 and the low-pressure bypass pipe port 81-4 and communicates the indoor heat exchanger side port 81-2 and the low-pressure gas pipe port 81-3. Accordingly, low-pressure gas is supplied to the indoor heat exchanger 30 in cooling operation.
A high-pressure gas bifurcated pipe on-off valve is provided on the high-pressure gas bifurcated pipe upstream of the indoor side four-way switching valve 81. A high-pressure gas bifurcated pipe bypass flow path is formed to bypass the high-pressure gas bifurcated pipe on-off valve and provided with a first capillary tube.
A second capillary tube is provided on the low-pressure bypass pipe downstream of the indoor side four-way switching valve 81.
A high-low-pressure bypass pipe (bypass pipe) is provided between the high-pressure gas bifurcated pipe upstream of the high-pressure gas bifurcated pipe bypass flow path and the indoor side low-pressure gas bifurcated pipe downstream of the low-pressure bypass pipe (downstream of the halfway position). The high-low-pressure bypass pipe is provided with a high-low-pressure bypass pipe on-off valve and a third capillary tube sequentially from the high-pressure gas bifurcated pipe side toward the indoor side low-pressure gas bifurcated pipe side.
The following describes control of the multiple-type air conditioning device 1 according to the present embodiment when the amount of refrigerant varies in cooling operation.
The sensing unit 71 determines whether the amount of circulating refrigerant tends to be excessive. Whether the amount of refrigerant is excessive is determined based on the temperature difference between temperatures at the exit part and the central part of the indoor heat exchanger 30 of each heating operation indoor unit 3.
As illustrated in FIG. 3, refrigerant circulates through the indoor heat exchanger 30 of the heating operation indoor unit 3 in the direction of the arrow. The indoor heat exchanger 30 of the heating operation indoor unit 3 is provided with, sequentially from the refrigerant exit side in heating operation, the exit-part temperature sensor 61, the central-part temperature sensor 62, and the entrance-part temperature sensor 63. The exit-part temperature sensor 61 measures the exit temperature T1, the central-part temperature sensor 62 measures the central-part temperature T2, and the entrance-part temperature sensor 63 measures the entrance temperature T3.
When an appropriate amount of refrigerant is circulating, high-temperature and high-pressure refrigerant gas flows in the entrance part of the indoor heat exchanger 30 (on the entrance-part temperature sensor 63 side) and is condensed to liquid through heat exchange with indoor air. Thus, the temperatures have the relation of T1 < T2 < T3.
When the amount of refrigerant is excessive, the receiver 16 is overfilled, and refrigerant is accumulated in the indoor heat exchanger 30 of the heating operation indoor unit 3. The exit temperature T1 and the central-part temperature T2 are substantially equal to each other, and thus the temperatures have the relation of T1 ≈ T2 < T3. The sensing unit 71 senses that the amount of refrigerant tends to be excessive when the temperature difference |T1 - T2| between the exit temperature T1 and the central-part temperature T2 becomes equal to or smaller than the first temperature difference. The first temperature difference is, for example, 5 deg.
In the multiple-type air conditioning device 1, when the amount of refrigerant at each operation indoor unit 3 is sensed to be excessive by the sensing unit 71, each indoor side four-way switching valve 81 is switched while the indoor electronic expansion valves 31 of all stop indoor units 3 are fully closed. Specifically, the high-pressure gas pipe port 81-1 and the indoor heat exchanger side port 81-2 are communicated with each other, and the low-pressure gas pipe port 81-3 and the low-pressure bypass pipe port 81-4 are communicated with each other.
In this state, since the indoor electronic expansion valves 31 of the stop indoor units 3 are fully closed, high-pressure gas flowing in through the high-pressure gas pipe port 81-1 and the indoor heat exchanger side port 81-2 is accumulated in the indoor heat exchanger 30.
In the multiple-type air conditioning device 1, when the amount of refrigerant at each operation indoor unit 3 is sensed to be insufficient, the indoor side four-way switching valve 81 of any one of the stop indoor units 3 is switched. Specifically, the indoor side four-way switching valve 81 communicates the high-pressure gas pipe port 81-1 and the low-pressure bypass pipe port 81-4, and communicates the indoor heat exchanger side port 81-2 and the low-pressure gas pipe port 81-3.
In this state, high-pressure gas accumulated in the indoor heat exchanger 30 is collected toward the low-pressure gas pipe 4L through the indoor heat exchanger side port 81-2 and the low-pressure gas pipe port 81-3.
Alternatively, similarly to heating, control may be performed to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3.
In the multiple-type air conditioning device 1 according to the present embodiment in heating operation, control same as that of the first embodiment is performed.
A control device of a multiple-type air conditioning device according to the present embodiment, the multiple-type air conditioning device, a method of controlling the multiple-type air conditioning device, and a computer program of controlling the multiple-type air conditioning device as described above achieve the following effects.
The present embodiment provides the control device 70 of the multiple-type air conditioning device 1 including at least one outdoor unit 2, the plurality of indoor units 3 each including the indoor electronic expansion valve 31, and the plurality of distribution controllers 8 corresponding to the respective indoor units 3. Each indoor unit 3 in operation is referred to as an operation indoor unit 3, each operation indoor unit 3 in heating operation is referred to as a heating operation indoor unit 3, and each indoor unit 3 at a stop is referred to as a stop indoor unit 3. When the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in each heating operation indoor unit 3 is equal to or lower than the first temperature difference and the amount of refrigerant is sensed to be excessive, at heating, the control device 70 performs control to close the indoor electronic expansion valves 31 of all stop indoor units 3. In the multiple-type air conditioning device 1 of a cooling and heating simultaneous type, when the amount of refrigerant at the operation indoor units 3 becomes excessive and performance degradation is sensed at heating, the indoor electronic expansion valves 31 of all stop indoor units 3 are closed, and refrigerant is accumulated in the indoor heat exchangers 30 of the stop indoor units 3.
When the amount of refrigerant is excessive, refrigerant is accumulated in the receiver 16 of the outdoor unit 2. When the amount of refrigerant becomes excessive beyond the accumulation capacity of the receiver 16, the amount of refrigerant at the operation indoor units 3 becomes excessive, which leads to performance degradation. Whether the amount of refrigerant has become excessive can be sensed based on whether the difference between the exit temperature T1 and the central-part temperature T2 of the indoor heat exchanger 30 included in each heating operation indoor unit 3 has become equal to or smaller than the first temperature difference. This is possible because the receiver 16 is overfilled so that the amount of refrigerant has become excessive, and refrigerant is accumulated in the indoor heat exchanger 30 of each heating operation indoor unit 3 so that the exit temperature T1 and the central-part temperature T2 has become substantially equal to each other.
At heating, the indoor electronic expansion valve 31 of each stop indoor unit 3 is typically slightly opened to avoid refrigerant accumulation so that the amount of refrigerant is prevented from becoming insufficient. When the amount of refrigerant is sensed to be excessive, the control device 70 performs control to close the indoor electronic expansion valves 31 of all stop indoor units 3. Accordingly, refrigerant is accumulated in the indoor heat exchangers 30 of all stop indoor units 3, and an appropriate amount of refrigerant is supplied to each operation indoor unit 3, thereby preventing performance degradation. Since the amount of refrigerant can be adjusted by controlling the indoor electronic expansion valve 31, it is not needed to increase the capacitor of the receiver 16 of the outdoor unit 2, which leads to cost reduction. At installation of the multiple-type air conditioning device 1, the charge amount of refrigerant is determined based on the number of indoor units 3 and the length of the refrigerant pipe. The amount of refrigerant can be adjusted by controlling the indoor electronic expansion valve 31, and thus the present invention is applicable to a case in which the charge amount is set to be larger than an appropriate amount.
At cooling, control is performed to switch the indoor side four-way switching valves 81 of the distribution controllers 8 corresponding to all stop indoor units 3 and close the indoor electronic expansion valves 31 of all stop indoor units 3. At cooling, when the amount of refrigerant is sensed to be excessive, the indoor side four-way switching valves 81 of the distribution controllers 8 are switched to close the indoor electronic expansion valves 31. Similarly to heating, refrigerant is accumulated in the indoor heat exchanger 30 of each stop indoor unit 3, and an appropriate amount of refrigerant can be supplied to the operation indoor unit 3.
According to the present embodiment, at heating, when the opening degree of the outdoor electronic expansion valve 15 of the outdoor unit 2 becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit 3 is sensed to be insufficient while the indoor electronic expansion valves 31 of one or more of the stop indoor units 3 are closed, control is performed to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3. At heating, when the indoor electronic expansion valves 31 of the stop indoor units 3 are closed so that refrigerant is accumulated in the indoor heat exchangers 30 and the amount of refrigerant at the operation indoor unit 3 becomes insufficient, and thus performance degradation is sensed, control is performed to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3 to collect the refrigerant accumulated in the indoor heat exchangers 30. In this manner, the amount of refrigerant at the operation indoor unit 3 can be corrected. Through repetition of the correction, a correct amount of refrigerant is supplied to the operation indoor unit 3, thereby achieving reliable operation of the multiple-type air conditioning device 1.
At cooling, when the opening degree of the outdoor electronic expansion valve 15 of the outdoor unit 2 becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit 3 is sensed to be insufficient while the indoor electronic expansion valves 31 of one or more of the stop indoor units 3 are closed, control is performed to switch the indoor side four-way switching valve 81 of the distribution controller 8 corresponding to any one of the stop indoor units 3 or control is performed to slightly open the indoor electronic expansion valve 31 of any one of the stop indoor units 3. At cooling, when the amount of refrigerant is sensed to be insufficient, refrigerant accumulated in the indoor heat exchanger 30 can be collected by switching the indoor side four-way switching valve 81 of any one of the distribution controllers 8 or by slightly opening the indoor electronic expansion valve 31 of any one of the stop indoor units 3, similarly to heating, so that an appropriate amount of refrigerant is supplied to the operation indoor unit 3 similarly to heating.
In heating operation, when a correct amount of refrigerant is supplied to the operation indoor unit 3, the electronic expansion valve of the evaporator, in other words, the outdoor electronic expansion valve 15 of the outdoor unit 2, or the indoor electronic expansion valve 31 of the indoor unit 3 is set to a predetermined opening degree. When the amount of refrigerant at the operation indoor unit 3 is insufficient, a larger amount of refrigerant needs to be circulated, and thus the opening degree of the outdoor electronic expansion valve 15 of the outdoor unit 2 or the indoor electronic expansion valve 31 of the indoor unit 3 is set to be equal to or higher than the predetermined opening degree. The predetermined opening degree is, for example, the maximum opening degree of the outdoor electronic expansion valve 15. Thus, the amount of refrigerant at the operation indoor unit 3 can be sensed to be insufficient by a simple method.
In cooling operation, when a correct amount of refrigerant is supplied to the operation indoor unit 3, the electronic expansion valve of the evaporator, in other words, the indoor electronic expansion valve 31 of the operation indoor unit 3 is set to a predetermined opening degree. When the amount of refrigerant at the operation indoor unit 3 is insufficient, a larger amount of refrigerant needs to be circulated, and thus the opening degree of the indoor electronic expansion valve 31 of the operation indoor unit 3 is set to be equal to or higher than the predetermined opening degree. The predetermined opening degree is, for example, the maximum opening degree of the indoor electronic expansion valve 31. Thus, the amount of refrigerant at the operation indoor unit 3 can be sensed to be insufficient by a simple method.

Reference Signs List

1: Multiple-type air conditioning device

2: Outdoor unit
3: Indoor unit
8: Distribution controller
10: Compressor
12: Outdoor-side four-way switching valve
13: Outdoor heat exchanger
15: Outdoor electronic expansion valve
16: Receiver
30: Indoor heat exchanger
31: Indoor electronic expansion valve
61: Exit-part temperature sensor
62: Central-part temperature sensor
63: Entrance-part temperature sensor
70: Control device
71: Sensing unit
72: Control unit
81: Side four-way switching valve

Claims

A control device of a multiple-type air conditioning device comprising:
at least one outdoor unit; and

a plurality of indoor units each including an indoor electronic expansion valve, wherein

each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit, and

control is performed to close the indoor electronic expansion valves of all stop indoor units when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference at heating and the amount of refrigerant is sensed to be excessive.
The control device of the multiple-type air conditioning device according to claim 1, wherein
the outdoor unit includes an outdoor electronic expansion valve, and
when the opening degree of the outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units.
A control device of a multiple-type air conditioning device comprising:
at least one outdoor unit;

a plurality of indoor units each including an indoor electronic expansion valve; and

a plurality of distribution controllers corresponding to the respective indoor units, wherein

each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit, and

when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive,

at heating, control is performed to close the indoor electronic expansion valves of all stop indoor units, or

at cooling, control is performed to switch four-way switching valves of the distribution controllers corresponding to all stop indoor units and close the indoor electronic expansion valves of all stop indoor units.
The control device of the multiple-type air conditioning device according to claim 3, wherein
at heating, when the opening degree of an outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units, and
at cooling, when the opening degree of the outdoor electronic expansion valve of the outdoor unit becomes equal to or higher than a predetermined opening degree and the amount of refrigerant at each operation indoor unit is sensed to be insufficient while the indoor electronic expansion valves of one or more of the stop indoor units are closed, control is performed to switch the four-way switching valve of the distribution controller corresponding to any one of the stop indoor units or control is performed to slightly open the indoor electronic expansion valve of any one of the stop indoor units.
The control device of the multiple-type air conditioning device according to claim 2 or 4, wherein the opening degree of the indoor electronic expansion valve of the stop indoor unit when slightly opened is an opening degree at which the refrigerant flow rate of the indoor electronic expansion valve is 10 to 20 kg/h.
The control device of the multiple-type air conditioning device according to any one of claims 1 to 5, wherein, when the difference between each of set temperatures of one or more of the operation indoor units and an indoor temperature is continuously equal to or larger than a second temperature difference for a time equal to or longer than a predetermined time and the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit is equal to or smaller than a first temperature difference, the amount of refrigerant at the operation indoor unit is sensed to be excessive.
A multiple-type air conditioning device comprising:
the control device according to claims 1 to 6;

at least one outdoor unit; and

a plurality of indoor units each including an indoor electronic expansion valve.
A method of controlling a multiple-type air conditioning device comprising:
at least one outdoor unit; and

a plurality of indoor units each including an indoor electronic expansion valve,

wherein each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit,

the method comprising a process of closing, at heating, the indoor electronic expansion valves of all stop indoor units when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive.
A computer program of controlling a multiple-type air conditioning device comprising:
at least one outdoor unit; and

a plurality of indoor units each including an indoor electronic expansion valve,

wherein each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit,

the computer program comprising a step of closing, at heating, the indoor electronic expansion valves of all stop indoor units when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive.
A method of controlling a multiple-type air conditioning device comprising:
at least one outdoor unit;

a plurality of indoor units each including an indoor electronic expansion valve; and

a plurality of distribution controllers corresponding to the respective indoor units,

wherein each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit,

the method comprising:
when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive,

a process of closing the indoor electronic expansion valves of all stop indoor units at heating; and

a process of switching four-way switching valves of the distribution controllers corresponding to all stop indoor units and closing the indoor electronic expansion valves of all stop indoor units at cooling.
A computer program of controlling a multiple-type air conditioning device comprising:
at least one outdoor unit;

a plurality of indoor units each including an indoor electronic expansion valve; and

a plurality of distribution controllers corresponding to the respective indoor units,

wherein each indoor unit in operation is referred to as an operation indoor unit, each operation indoor unit in heating operation is referred to as a heating operation indoor unit, and each indoor unit at a stop is referred to as a stop indoor unit,

the program comprising:
when the difference between an exit temperature and a central-part temperature of an indoor heat exchanger included in each heating operation indoor unit becomes equal to or lower than a first temperature difference and the amount of refrigerant is sensed to be excessive,

a step of closing the indoor electronic expansion valves of all stop indoor units at heating, and

a step of switching four-way switching valves of the distribution controllers corresponding to all stop indoor units and closing the indoor electronic expansion valves of all stop indoor units at cooling.