Refrigerant charge assisting device, air-conditioning apparatus, and refrigerant charge assisting program

• US 9,188,376 B2
• Filed: 12/20/2012
• Issued: 11/17/2015
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Tamaki, Shogo, Unezaki, Fumitake, Kasai, Tomohiko, Shinozaki, Kazuyoshi
• Primary Examiner(s): Norman, Marc
• Application Number:
  US13/721,275
• Publication Number:
  US 20140174114A1
• Time in Patent Office: 1,062 Days
• Field of Search: 62/77, 621/49, 621/74, 622/92
• US Class Current: 1/1
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/006 two pipes connecting the outdoor side to the indoor side with multiple indoor units
• CPC Class Codes: F25B 2313/0231 with simultaneous cooling and heating
• CPC Class Codes: F25B 2313/0233 in parallel arrangements
• CPC Class Codes: F25B 2313/02741 using one four-way valve
• CPC Class Codes: F25B 2313/0311 Pressure sensors near the expansion valve
• CPC Class Codes: F25B 2313/0314 Temperature sensors near the indoor heat exchanger
• CPC Class Codes: F25B 2313/0315 Temperature sensors near the outdoor heat exchanger
• CPC Class Codes: F25B 2345/001 Charging refrigerant to a cycle
• CPC Class Codes: F25B 2345/003 Control issues for charging or collecting refrigerant to or from a cycle
• CPC Class Codes: F25B 2400/13 Economisers
• CPC Class Codes: F25B 2400/23 Separators
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2500/23 High amount of refrigerant in the system
• CPC Class Codes: F25B 2500/24 Low amount of refrigerant in the system
• CPC Class Codes: F25B 2600/0253 with variable speed
• CPC Class Codes: F25B 2600/05 Refrigerant levels
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/2103 near a heat exchanger
• CPC Class Codes: F25B 2700/2104 : of an indoor room or compartment
• CPC Class Codes: F25B 2700/2106 : of fresh outdoor air
• CPC Class Codes: F25B 2700/21152 : at the discharge side of the compressor
• CPC Class Codes: F25B 45/00 : Arrangements for charging or discharging refrigerant
• CPC Class Codes: F25B 49/022 : Compressor control arrangements
• CPC Class Codes: Y02B 30/70 : Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

Operation data of a refrigerant circuit is acquired after an initial refrigerant charge amount of refrigerant is charged in the refrigerant circuit and operation of the refrigerant circuit is started, an internal volume of a high-pressure pipe 6 is computed from the obtained operation data and the initial refrigerant charge amount input in a input unit 112, a target refrigerant charge amount is computed from the computed internal volume of the high-pressure pipe 6 and a standard operating state acquired in advance, the standard operating state being operation data of the refrigerant circuit when the refrigerant circuit is in a standard operating state that satisfies a preset condition, and an additional refrigerant charge amount is computed from the target refrigerant charge amount and the initial refrigerant charge amount.

Claims

1. A refrigerant charge assisting device used when a refrigerant is charged into a refrigerant circuit of an air-conditioning apparatus in which the refrigerant circuit is formed by one or more heat source units including a compressor and a heat source side heat exchanger and one or more use units including a use side pressure reduction mechanism and a use side heat exchanger, the one or more heat source units and the one or more use units being connected with a liquid side refrigerant extension pipe and a gas side refrigerant extension pipe, the refrigerant charge assisting device comprising:

an input unit that is input with an initial refrigerant charge amount;

an operation data acquisition unit that starts operation of the refrigerant circuit and acquires operation data of the refrigerant circuit after the initial refrigerant charge amount of refrigerant is charged in the refrigerant circuit;

a charge amount computing unit that computes

an internal volume of the liquid side refrigerant extension pipe from the initial refrigerant charge amount input to the input unit and the operation data acquired by the operation data acquisition unit,

a target refrigerant charge amount from the internal volume of the liquid side refrigerant extension pipe and a standard operating state acquired in advance, the standard operating state being operation data of the refrigerant circuit when the refrigerant circuit is in a standard operating state that satisfies a preset condition, and

an additional refrigerant charge amount on a basis of the target refrigerant charge amount and the initial refrigerant charge amount; and

a display unit that displays the additional refrigerant charge amount computed by the charge amount computing unit.

2. The refrigerant charge assisting device of claim 1, further comprising a determination unit that determines whether an operating state of the refrigerant circuit has become stable, wherein

the operation of the refrigerant circuit started by the operation data acquisition unit is a refrigerant charge amount detection operation that turns a liquid reservoir provided in the refrigerant circuit into a state in which there is no refrigerant in the liquid reservoir by operating the refrigerant circuit such that a superheating is obtained in the use side heat exchanger

the charge amount computing unit uses the operation data acquired after the operating state of the refrigerant circuit is determined to have become stable by the determination unit after start of the refrigerant charge amount detection operation, in order to compute the internal volume of the liquid side refrigerant extension pipe.

3. The refrigerant charge assisting device of claim 2, wherein

further, in the refrigerant charge amount detection operation, the operating frequency of the compressor is controlled such that an evaporating temperature between the use side heat exchanger and the compressor is constant at a permissible minimum evaporating temperature.

4. The refrigerant charge assisting device of claim 3, wherein

further, in the refrigerant charge amount detection operation, the opening degree of the use side pressure reduction mechanism is controlled and the superheat of the use side heat exchange is increased such that the evaporating temperature between the use side heat exchanger and the compressor is constant at a permissible minimum evaporating temperature.

5. The refrigerant charge assisting device of claim 2, wherein

further, in the refrigerant charge amount detection operation,

a rotation speed of a heat source side fan is controlled such that a temperature difference between a condensing temperature between the compressor and the use side pressure reduction mechanism and an outside air temperature is constant or is controlled such that the rotation speed is fixed in accordance with the outside air temperature.

6. The refrigerant charge assisting device of claim 2, wherein

the operation data acquisition unit sequentially acquires the operation data, and

the determination unit determines that the operating state has become stable when, on a basis of the sequentially acquired operation data, at least one of changes in a subcooling between the heat source side heat exchanger and the use side pressure reduction mechanism, a discharge temperature of the compressor, and the pressure between the compressor and the use side pressure reduction mechanism is determined to have become smaller than a predetermined value for discriminating whether the refrigerant is flowing out from the liquid reservoir.

7. The refrigerant charge assisting device of claim 1, wherein

the preset condition of the standard operation state is a temperature condition in which the heat source side fan that sends air to the heat source side heat exchanger is at a maximum available rotation speed.

8. The refrigerant charge assisting device of claim 1, wherein

in the display of the additional refrigerant charge amount

when the additional refrigerant charge amount computed by the charge amount computing unit is a positive value and the ratio of the additional refrigerant charge amount to the target refrigerant charge amount is equivalent to or smaller than a predetermined percentage that discriminates whether there is to be any subcooling between the heat source side heat exchanger and the use side pressure reduction mechanism, the computed additional refrigerant charge amount is displayed as it is, and when the ratio of the additional refrigerant charge amount to the target refrigerant charge amount exceeds the predetermined percentage, a value that is equivalent to or smaller than the predetermined percentage and that is larger than zero percent of the target refrigerant charge amount is displayed, and

when the additional refrigerant charge amount computed by the charge amount computing unit is a negative value, the value is displayed as a overcharged amount.

9. The refrigerant charge assisting device of claim 8, wherein the predetermined percentage is 20%.

10. The refrigerant charge assisting device of claim 1, wherein

the charge amount computing unit computes the internal volume of the liquid side refrigerant extension pipe assuming that a refrigerant state between the heat source side heat exchanger and the use side pressure reduction mechanism is in a saturated liquid state when there is no subcooling between the heat source side heat exchanger and the use side pressure reduction mechanism.

11. The refrigerant charge assisting device of claim 1, wherein

the operation data acquisition unit acquires an upstream side temperature of the liquid side refrigerant extension pipe and a downstream side temperature of the liquid side refrigerant extension pipe, and

the charge amount computing unit uses the upstream side temperature and the downstream side temperature in computing the internal volume of the liquid side refrigerant extension pipe.

12. The refrigerant charge assisting device of claim 1, wherein

the heat source unit further includes a subcooling heat exchanger that exchanges heat between a high-pressure refrigerant that has passed through the heat source side heat exchanger and a low-pressure refrigerant that is a portion of the high-pressure refrigerant, which has been decompressed, and

the charge amount computing unit determines whether an outlet of the heat source side heat exchanger is in a liquid phase state or in a two-phase state from an operating state of the subcooling heat exchanger when there is a subcooling between the heat source side heat exchanger and the use side pressure reduction mechanism, computes a refrigerant density of the heat source side heat exchanger in accordance with a determination result of the charge amount computing unit, and uses the refrigerant density of the heat source side heat exchanger for computing the internal volume of the liquid side refrigerant extension pipe.

13. An air-conditioning apparatus comprising the refrigerant charge assisting device and the refrigerant circuit of claim 1.

14. A non-transitory information storage medium storing thereon a refrigerant charge assisting program for a refrigerant circuit of an air-conditioning apparatus in which the refrigerant circuit is formed by one or more heat source units including a compressor and a heat source side heat exchanger and one or more use units including a use side pressure reduction mechanism and a use side heat exchanger, the one or more heat source units and the one or more use units being connected with a liquid side refrigerant extension pipe and a gas side refrigerant extension pipe, that, when the refrigerant charge assisting program is executed by at least one computer, causes the at least one computer to:

start, by an operation data acquisition unit, operation of the refrigerant circuit of the air-conditioning apparatus and acquires operation data of the refrigerant circuit after the initial refrigerant charge amount of refrigerant is charged in the refrigerant circuit; and

compute, in a charge amount computing unit,

an internal volume of the liquid side refrigerant extension pipe from the initial refrigerant charge amount input to the input unit and the operation data acquired by the operation data acquisition unit,

a target refrigerant charge amount from the internal volume of the liquid side refrigerant extension pipe and a standard operating state acquired in advance, the standard operating state being operation data of the refrigerant circuit when the refrigerant circuit is in a standard operating state that satisfies a preset condition, and

an additional refrigerant charge amount on a basis of the target refrigerant charge amount and the initial refrigerant charge amount.