EP4585862A1

EP4585862A1 - Air conditioner

Info

Publication number: EP4585862A1
Application number: EP22924561.8A
Authority: EP
Inventors: Koji Naito; Shuuhei Tada; Jeangmin LEE
Original assignee: Hitachi Johnson Controls Air Conditioning Inc
Current assignee: Hitachi Johnson Controls Air Conditioning Inc
Priority date: 2022-09-05
Filing date: 2022-09-05
Publication date: 2025-07-16
Also published as: JPWO2024052951A1; EP4585862A4; JP7217395B1; WO2024052951A1

Abstract

An object of the present invention is to provide an air-conditioner capable of ensuring safety when flammable refrigerant is used. An air-conditioner using flammable refrigerant includes ion-exchange resin having a sulfonic acid group or an ammonium group as a functional group and placed in a flow path of the refrigerant. An acid component of the refrigerant flowing in a refrigeration cycle reacts with the functional group according to operation of the air-conditioner to generate a first odor substance.

Description

TECHNICAL FIELD

The present invention relates to an air-conditioner.

BACKGROUND ART

In order to prevent global warming, refrigerant having a high global warming potential (GWP) has been switched to refrigerant having a low GWP. For a room air-conditioner, candidates for refrigerant include flammable refrigerant (R290). In China and India, room air-conditioner products using R290 have been marketed, but have not been widely used. In addition, in Japan, there is a risk of refrigerant leakage and ignition or combustion at the time of operation, installation, repair, and removal, and for this reason, products have not been marketed.
As a technique that addresses the refrigerant leakage, Patent Literature 1 discloses a technique of driving an indoor fan when the refrigerant leak is sensed. Household propane gas has been required to have an odor, and it has been known that when the leakage occurs, a door or a window is largely opened to discharge the gas.

CITATION LIST

PATENT LITERATURE

PATENT LITERATURE 1: Japanese Patent No. 6861804

SUMMARY OF INVENTION

PROBLEMS TO BE SOLVED BY INVENTION

For the air-conditioner, the refrigerant leakage can be sensed at an early stage by the odor of the refrigerant, and the risk of combustion can be reduced. However, since the refrigerant has a high temperature of about 100°C in a compressor, there is a risk that the refrigerant reacts with iron or copper in a refrigerant pipe and accordingly a sulfur compound decreases and the odor decreases.
The present invention has been made in view of these problems, and an object of the present invention is to provide an air-conditioner capable of ensuring safety when flammable refrigerant is used.

SOLUTION TO PROBLEMS

The present invention relates to an air-conditioner using flammable refrigerant, the air-conditioner including ion-exchange resin having a sulfonic acid group or an ammonium group as a functional group and placed in a flow path of the refrigerant. An acid component of the refrigerant flowing in a refrigeration cycle reacts with the functional group according to operation of the air-conditioner to generate a first odor substance.

EFFECTS OF INVENTION

According to the present invention, the safety can be ensured when the flammable refrigerant is used.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a diagram illustrating an air-conditioner according to a first embodiment; and
Fig. 2 is a graph of an odor substance.

DESCRIPTION OF EMBODIMENTS

Fig. 1 is a schematic diagram of a refrigerant circuit of an air-conditioner 1 according to an embodiment. The air-conditioner 1 includes an outdoor unit 10 and two indoor units 20a, 20b. The outdoor unit 10 and the indoor units 20a, 20b are connected to each other through a liquid pipe 31 and a gas pipe 32. Note that a plurality of outdoor units may be connected to one indoor unit or a plurality of indoor units may be connected to one outdoor unit. Solid arrows illustrated in Fig. 1 indicate the flow of refrigerant during cooling operation. Dashed arrows illustrated in Fig. 1 indicate the flow of refrigerant during heating operation.
As illustrated in Fig. 1, the outdoor unit 10 includes a four-way valve 11, an accumulator 12, a compressor 13, an oil separator 14, an outdoor heat exchanger 15, and an outdoor expansion valve 16. The indoor units 20a, 20b each include indoor heat exchangers 21a, 21b and indoor expansion valves 22a, 22b.
The four-way valve 11 switches a flow path of the refrigerant according to the operation mode of the air-conditioner 1. By switching the four-way valve 11, a refrigeration cycle is formed in the cooling operation, in which the refrigerant circulates in the accumulator 12, the compressor 13, the oil separator 14, the outdoor heat exchanger 15 (condenser), the outdoor expansion valve 16, the indoor expansion valves 22a, 22b, and the indoor heat exchangers 21a, 21b (evaporators) in this order as indicated by the solid arrows. By switching the four-way valve 11, a refrigeration cycle is formed in the heating operation, in which the refrigerant circulates in the accumulator 12, the compressor 13, the oil separator 14, the indoor heat exchangers 21a, 21a (condensers), the indoor expansion valves 22a, 22b, the outdoor expansion valve 16, and the outdoor heat exchanger 15 (evaporator) in this order as indicated by the dashed arrows.
The accumulator 12 is a container that adjusts the refrigerant discharged from the evaporator to a predetermined refrigerant dryness and discharges the refrigerant to a suction pipe of the compressor 13. Even when there is an excessive inflow of liquid refrigerant during air-conditioning operation of the air-conditioner 1, the refrigerant having the predetermined dryness is supplied to the compressor 13 to avoid liquid compression of the compressor 13 and ensure the reliability of the compressor 13. The oil separator 14 separates gas refrigerant and refrigerator oil, which is discharged from the compressor 13 together with the gas refrigerant, from each other. The outlet side of the oil separator 14 is connected to the accumulator 12 through an oil return pipe 33, and the refrigerator oil is returned to the compressor 13 through the accumulator 12. Note that the position of the oil return pipe 33 is not limited to this position and may be connected to between the accumulator 12 and the compressor 13.
In the present embodiment, ion-exchange resin 40 is placed in the oil return pipe 33. The ion-exchange resin 40 is anionic ion-exchange resin, and a functional group (N⁺(CH₃)₃OH) on the surface of the ion-exchange resin is an ammonium group represented by Chemical Formula (1).
As the refrigerant for the air-conditioner 1, flammable refrigerant is used. As the flammable refrigerant, for example, CFC refrigerant, HCFC refrigerant, HFC refrigerant, or natural refrigerant is used, and refrigerant containing R290 is preferably used. Further, it is assumed that an organic compound of sulfur (S) (hereinafter referred to as a sulfur compound) is added to the refrigerant as an odor substance before the air-conditioning operation. Examples of the sulfur compound include tert-butyl mercaptan (C₄H₁₀S) represented by Chemical Formula (2).
With this configuration, for example, at the time of installation, operation, repair, or removal of the air-conditioner 1, leakage of the flammable refrigerant can be sensed by the odor of the sulfur compound.
However, since the refrigerant has a high temperature, there is a problem that the refrigerant reacts with iron or copper in a refrigerant pipe and accordingly the sulfur compound decreases and the odor decreases. On the other hand, in the air-conditioner 1 of the present embodiment, the ion-exchange resin 40 is placed as described above. The ion-exchange resin 40 has the ammonium group as the functional group, and reacts with an anionic substance (F^-) in the refrigerant to generate OH^- and, at the same time, generate an amine compound that generates a fishy odor. Here, the amine compound is an example of a first odor substance, and the above-described sulfur compound is an example of a second odor substance.
Further, in a case where there is liquid refrigerator oil, a large amount of acid component is accumulated in the oil, and the performance of the ion-exchange resin 40 is enhanced. Since a relatively-large amount of oil is present in the oil return pipe 33, the ion-exchange resin 40 placed in the oil return pipe 33 exhibits high exchange performance. Note that the refrigerator oil is not specifically limited as long as the refrigerator oil can be used in a refrigeration cycle device, and examples thereof include synthetic oils such as PVE, POE, and PAG and mineral oils.
Fig. 2 is a graph for describing a change in the amount of odor substance over operation time. The horizontal axis of the graph indicates the operation time of the air-conditioner 1, and the vertical axis of the graph indicates the amount of odor substance in the refrigerant. A line t1 indicates the amount of sulfur compound added to the refrigerant, and a line t2 indicates the amount of amine compound produced by reaction of the ion-exchange resin 40. A line t3 indicates the sum of the amount of sulfur compound indicated by the line t1 and the amount of amine compound indicated by the line t2.
As illustrated in the graph of Fig. 2, the amount of sulfur compound added to the refrigerant gradually decreases as the operation time passes. On the other hand, as the operation time passes, the reaction in the ion-exchange resin 40 progresses and the amount of amine compound gradually increases. As a result, the total amount of odor substances contained in the refrigerant can be maintained at a value before operation. That is, even after the operation time has elapsed, a decrease in the odor of the refrigerant can be avoided. Consequently, even after the operation time has elapsed, the refrigerant leakage can be sensed by the odor.
As described above, in the air-conditioner 1 of the present embodiment, even after the operation time has elapsed, a decrease in the odor substance can be avoided. This makes it possible to ensure safety when the flammable refrigerant is used. In the air-conditioner 1, when the refrigerant containing the odorant is used, even when the effect of the odorant is lost due to continuation of the air-conditioning operation, the refrigerant is newly odorized in the refrigeration cycle, so that the odor is maintained for a long period of time.

Example 1

In a refrigeration cycle of refrigerant containing CF₃I, anionic ion-exchange resin was placed in an oil return pipe, and air-conditioning operation was performed for five hours. At this time, the temperature of a high-temperature portion (compressor) of the refrigeration cycle was 70°C to 90°C. Thereafter, when oil was recovered from an oil separator, it was confirmed that the oil has a fishy odor.
As a first modification of the embodiment, the location where the ion-exchange resin 40 is placed is not limited to that of the embodiment. As another example, the ion-exchange resin 40 may be placed in the liquid pipe 31. As still another example, the ion-exchange resin 40 may be placed in the accumulator 12.
As a second modification, ion-exchange resin having a sulfonic acid group (SO₃H) as a functional group may be used as the ion-exchange resin of the air-conditioner 1. In this case, a sulfur compound which is an odor substance is produced by ion exchange. Thus, even after the operation time has elapsed, a decrease in the odor of the refrigerant can be avoided.
Note that the present invention is not limited to the specific embodiment and various modifications and changes can be made within the scope of the gist of the present invention described in the claims, for example, by applying a modification of a certain embodiment to another embodiment.

LIST OF REFERENCE NUMBERS

1: Air-Conditioner
10: Outdoor Unit
11: Four-Way Valve
12: Accumulator
13: Compressor
14: Oil Separator

15: Outdoor Heat Exchanger
16: Outdoor Expansion Valve
20a, 20b: Indoor Unit
21a, 21b: Indoor Heat Exchanger
22a, 22b: Indoor Expansion Valve
31: Liquid Pipe
32: Gas Pipe
33: Oil Return Pipe
40: Ion-Exchange Resin

Claims

An air-conditioner using flammable refrigerant, comprising:
ion-exchange resin having a sulfonic acid group or an ammonium group as a functional group and placed in a flow path of the refrigerant,

wherein an acid component of the refrigerant flowing in a refrigeration cycle reacts with the functional group according to operation of the air-conditioner to generate a first odor substance.
The air-conditioner according to claim 1, wherein the ion-exchange resin is placed in a pipe, in which oil circulates, in the flow path.
The air-conditioner according to claim 1, further comprising:
an oil separator,

wherein the ion-exchange resin is placed in a refrigerant pipe on an outlet side of the oil separator.
The air-conditioner according to claim 1, further comprising:
an accumulator,

wherein the ion-exchange resin is placed in the accumulator.
The air-conditioner according to any one of claims 1 to 2, wherein the refrigerant contains a second odor substance.