JP2016044856A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of an air conditioner by suppressing liquid compression in a compressor at non-steady time, regarding the air conditioner which uses R32 as a circulating refrigerant in a refrigeration cycle including the compressor, an indoor heat exchanger, expansion means and an outdoor heat exchanger.SOLUTION: In an air conditioner which uses R32 as a circulating refrigerant in a refrigeration cycle including a compressor, an indoor heat exchanger, expansion means, and an outdoor heat exchanger, in the case where a capacity class of the air conditioner is below 4 kW, a filling amount of the R32 with respect to the refrigeration cycle is within a range of 200-300 g per total volume 1 liter of the whole refrigeration cycle, and in the case where the capacity class of the air conditioner is equal to or greater than 4 kW, the filling amount of the R32 with respect to the refrigeration cycle is within a range of 250-350 g per total volume 1 liter of the whole refrigeration cycle.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner using R32 as a refrigerant to be circulated in a refrigeration cycle including a compressor, an indoor heat exchanger, an expansion means, and an outdoor heat exchanger.

  Conventionally, R410A or the like has been mainly used as a refrigerant for an air conditioner. On the other hand, in recent years, use of R32 having a small warming coefficient has been promoted from the viewpoint of reducing the warming coefficient of the refrigerant. As an air conditioner using R32 as a refrigerant, for example, there is an air conditioner disclosed in Patent Document 1.

  In the air conditioner of Patent Document 1, in order to realize an energy-saving air conditioner that responds to global warming, by setting the filling ratio of R32 in a desired range, the coefficient of performance COP (Coeficient of Performance) in the steady state is set. I try to improve.

JP 2001-194016 A

  However, in addition to the improvement of COP in steady state as noted in Patent Document 1, it is required to further improve the reliability of the air conditioner using R32.

  Accordingly, an object of the present invention is to provide an air conditioner with improved reliability.

  In order to achieve the above object, the present invention is configured as follows.

According to one aspect of the present invention, in a refrigeration cycle including a compressor, an indoor heat exchanger, an expansion means, and an outdoor heat exchanger, an air conditioner using R32 as a circulating refrigerant,
An air conditioner is provided in which the capacity class of the air conditioner is less than 4 kW and the filling amount of R32 to the refrigeration cycle is in the range of 200 to 300 g per liter of the total volume of the refrigeration cycle.

According to one aspect of the present invention, in a refrigeration cycle including a compressor, an indoor heat exchanger, an expansion means, and an outdoor heat exchanger, an air conditioner using R32 as a circulating refrigerant,
Provided is an air conditioner in which the capacity class of the air conditioner is 4 kW or more and the filling amount of R32 to the refrigeration cycle is in the range of 250 to 350 g per liter of the total volume of the refrigeration cycle.

  According to the present invention, the reliability of the air conditioner can be improved.

The figure which shows the structure of the refrigerating cycle of the air conditioner concerning embodiment of this invention. The figure explaining the flow of the refrigerant | coolant in the refrigerating cycle at the time of air_conditionaing | cooling operation The figure explaining the flow of the refrigerant in the refrigerating cycle at the time of heating operation The figure which shows the result of the experiment conducted using the air conditioner concerning embodiment. The figure which shows the result of the experiment conducted using the air conditioner concerning embodiment. The figure which shows the result of the experiment conducted using the air conditioner concerning embodiment.

The first invention is an air conditioner using R32 as a refrigerant to be circulated in a refrigeration cycle including a compressor, an indoor heat exchanger, expansion means, and an outdoor heat exchanger,
It is an air conditioner in which the capacity class of the air conditioner is less than 4 kW, and the filling amount of R32 to the refrigeration cycle is in the range of 200 to 300 g per liter of the total volume of the refrigeration cycle. In this way, by setting the filling amount of R32 within a desired range, liquid compression in the compressor at the unsteady time can be suppressed, and the reliability of the air conditioner can be improved.

A second invention is an air conditioner using R32 as a refrigerant to be circulated in a refrigeration cycle including a compressor, an indoor heat exchanger, an expansion means, and an outdoor heat exchanger,
It is an air conditioner in which the capacity class of the air conditioner is 4 kW or more, and the filling amount of R32 for the refrigeration cycle is in the range of 250 to 350 g per liter of the total volume of the refrigeration cycle. In this way, by setting the filling amount of R32 within a desired range, liquid compression in the compressor at the unsteady time can be suppressed, and the reliability of the air conditioner can be improved.

  According to a third invention, in the first invention, the filling amount of R32 with respect to the refrigeration cycle is in the range of 750 g to 1100 g per liter of the volume of the outdoor heat exchanger. In this way, by setting the filling amount of R32 within a desired range, liquid compression in the compressor at the unsteady time can be suppressed, and the reliability of the air conditioner can be improved.

  4th invention WHEREIN: The filling amount of R32 with respect to a refrigerating cycle in 2nd invention exists in the range of 750g-1200g per liter of volumes of an outdoor heat exchanger. In this way, by setting the filling amount of R32 within a desired range, liquid compression in the compressor at the unsteady time can be suppressed, and the reliability of the air conditioner can be improved.

(Embodiment)
Drawing 1 is a figure showing the refrigerating cycle constituted by air harmony machine 1 concerning an embodiment.

  As shown in FIG. 1, the air conditioner 1 in the present embodiment includes a plurality of constituent members 2-7, and these constituent members 2-7 are connected by a plurality of pipes 8-14, thereby circulating the refrigerant. The refrigeration cycle is configured. In the present embodiment, R32 having a small warming coefficient is used as the refrigerant.

  As shown in FIG. 1, the air conditioner 1 includes a compressor 2, an indoor heat exchanger 3, an expansion means 4, an outdoor heat exchanger 5, a switching valve 6, and an accumulator 7. The switching valve 6 is a valve for switching the refrigerant flow path, and the accumulator 7 performs gas-liquid separation of the circulating refrigerant. In addition, the accumulator 7 in this embodiment is provided with a sight glass (not shown) for visually confirming the state of the refrigerant in the accumulator 7.

  The plurality of pipes 8-14 connecting the constituent members include a first pipe 8, a second pipe 9, a third pipe 10, a fourth pipe 11, and a fifth pipe 12. A sixth pipe 13 and a seventh pipe 14 are provided. The first pipe 8 connects the compressor 2 and the switching valve 6, the second pipe 9 connects the switching valve 6 and the indoor heat exchanger 3, and the third pipe 10 connects the indoor heat exchanger 3. And the expansion means 4 are connected, the fourth pipe 11 connects the expansion means 4 and the outdoor heat exchanger 5, the fifth pipe 12 connects the outdoor heat exchanger 5 and the switching valve 6, The pipe 13 connects the switching valve 6 and the accumulator 7, and the seventh pipe 14 connects the accumulator 7 and the compressor 2.

  The flow of the refrigerant in the refrigeration cycle of the air conditioner 1 including the above-described component 2-7 and the plurality of pipes 8-14 will be described in order for the three operation modes of the cooling operation, the heating operation, and the defrosting operation. .

(Cooling operation)
The flow of the refrigerant in the refrigeration cycle during the cooling operation of the air conditioner 1 is shown in FIG. As shown in FIG. 2, during the cooling operation, the refrigerant is the indoor heat exchanger 3, the second pipe 9, the switching valve 6, the sixth pipe 13, the accumulator 7, the seventh pipe 14, the compressor 2, the second 1 pipe 8, switching valve 6, fifth pipe 12, outdoor heat exchanger 5, fourth pipe 11, expansion means 4, third pipe 10, and indoor heat exchanger 3.

  With such a refrigerant flow, the refrigerant flowing into the indoor heat exchanger 3 is vaporized, and the air cooled by the vaporization heat at that time is supplied into the room, so that the cooling operation to the room is performed.

(Heating operation)
The flow of the refrigerant in the refrigeration cycle during the heating operation of the air conditioner 1 is shown in FIG. The refrigerant flow during the heating operation is opposite to that during the cooling operation described above. Specifically, as shown in FIG. 3, the refrigerant includes an indoor heat exchanger 3, a third pipe 10, an expansion means 4, a fourth pipe 11, an outdoor heat exchanger 5, a fifth pipe 12, and switching. The valve 6, the sixth pipe 13, the accumulator 7, the seventh pipe 14, the compressor 2, the first pipe 8, the switching valve 6, the second pipe 9, and the indoor heat exchanger 3 flow in this order.

  The refrigerant flowing into the indoor heat exchanger 3 is condensed by such a refrigerant flow, and air heated by the condensation heat at that time is supplied to the room, thereby heating the room indoors.

  During this heating operation, especially when the outdoor temperature is low (for example, 0 ° C. or less), frost may adhere to the surface of the outdoor heat exchanger 5 that exchanges heat with the outdoor. In order to melt the frost adhering to the outdoor heat exchanger 5, the air conditioner 1 in the present embodiment can perform the defrosting operation by switching the switching valve 6 from the heating operation.

(Defrosting operation)
In the present embodiment, the refrigerant flow during the defrosting operation is in the opposite direction to that during the heating operation, that is, in the same direction as during the cooling operation (the direction shown in FIG. 2). The difference from the cooling operation is that although the refrigerant is circulated in the refrigeration cycle, the air heat exchanged by the indoor heat exchanger 3 is not blown into the room. By performing such an operation, the refrigerant having a relatively high temperature is allowed to flow through the outdoor heat exchanger 5 in the same refrigerant flow as that during the cooling operation without performing the air conditioning operation for the room, so that it adheres to the outdoor heat exchanger 5. Frost can be removed.

  As a result of diligent study on the air conditioner 1 that can implement the three operation modes described above, the present inventors have particularly studied the transition period (when switching the operation mode or restarting the stopped operation). It was found that in the unsteady state, the liquid refrigerant returns to the compressor 2 and the liquid compression phenomenon may occur in the compressor 2. The liquid compression is a phenomenon in which a liquid refrigerant is compressed in the compressor 2 and can cause a failure of the compressor 2. Therefore, the present inventors conducted various experiments (Examples) in order to suppress the occurrence of liquid compression. The contents of the experiment will be described below.

(Example)
Specifically, using the same air conditioner 1 as described above, operation is performed under the following conditions 1 and 2, and at that time, whether or not the liquid compression phenomenon occurs in the compressor 2 Was visually confirmed from the sight glass of the compressor 2.

Condition 1: When the cooling operation is performed when the surroundings are at a high temperature (see the following temperature), and the cooling operation is restarted immediately after the cooling operation is stopped.
Indoor dry bulb temperature: 32 ° C
Indoor wet bulb temperature: 22.5 ° C
Outdoor dry bulb temperature: 43 ° C
Outdoor wet bulb temperature: 25.5 ° C

Condition 2: When heating operation is performed when the surroundings are at a low temperature (see the following temperature), switching to the defrosting operation is performed in the middle of the heating operation, and then returning to the heating operation.
Indoor dry bulb temperature: 20 ° C
Indoor wet bulb temperature:-℃
Outdoor dry bulb temperature: 2 ℃
Outdoor wet bulb temperature: 1 ° C

  In addition to the conditions 1 and 2, the refrigerant amount (g) in the entire refrigeration cycle of each capacity class (2.2 kW, 2.8 kW, 3.6 kW, 4 kW, 5 kW, 7 kW) of the air conditioner 1 is appropriately set. The experiment was conducted while changing. The capacity class of the air conditioner 1 represents the heating / cooling capacity of the air conditioner 1, and in this embodiment, means the heat energy removed from the room or applied to the room per unit time. Not only such a definition but various definitions may be made.

  The experimental results obtained by combining these conditions are shown in FIG. In FIG. 4, the vertical axis represents the refrigerant amount (g) of the entire refrigeration cycle / the total volume (L) of the entire refrigeration cycle, and the horizontal axis represents the capacity class (kW) of the air conditioner 1. In FIG. 4, “× 1” indicates that a liquid compression phenomenon has occurred in the compressor 2. In addition, the display of “× 2” indicates that the liquid compression phenomenon did not occur in the compressor 2, but the heat exchange performance is not sufficient because the amount of refrigerant is small. Further, “◯” indicates that the liquid compression phenomenon does not occur in the compressor 2 and that the heat exchange performance is sufficient.

  As shown in FIG. 4, when the capacity class of the air conditioner 1 is 2.2, 2.8, 3.6 kW, the R32 filling amount for the refrigeration cycle is set to 200 per liter of the total volume of the refrigeration cycle. It turns out that the phenomenon of liquid compression does not occur and heat exchange performance is sufficient because it is in the range of −300 g. When the capacity class of the air conditioner 1 is 4 kW, 5 kW, or 7 kW, the amount of R32 filled in the refrigeration cycle is set within the range of 250 to 350 g per liter of the total volume of the refrigeration cycle. It turns out that the phenomenon of compression does not occur and the heat exchange performance is sufficient, which is preferable.

  That is, when the capacity class of the air conditioner 1 is less than 4 kW (for example, 2.2 kW, 2.8 kW 3.6 kW), the R32 filling amount for the refrigeration cycle is set to 200-300 g per liter of the total volume of the refrigeration cycle. When the capacity class of the air conditioner 1 is 4 kW or more (for example, 4 kW, 5 kW, 7 kW), the filling amount of R32 for the refrigeration cycle is 250-350 g per liter of the total volume of the refrigeration cycle. Within the range, it can be seen that it is preferable from the viewpoint of suppressing liquid compression and maintaining heat exchange performance.

  With respect to the experiment described with reference to FIG. 4, the present inventors have further intensively studied the frequency of occurrence of liquid compression. As a result, it has been found that the condition of liquid compression is more likely to occur in the condition 1 in which the cooling operation is performed than in the condition 2 in which the heating operation is performed.

  Specifically, in the indoor heat exchanger 3 and the outdoor heat exchanger 5, the outdoor heat exchanger 5 usually has a larger internal volume, and during the cooling operation as in condition 1, the outdoor heat exchanger 5 The alternator 5 functions as a condenser that condenses the refrigerant to make it liquid. That is, when the cooling operation is being performed as in Condition 1, the operation is temporarily stopped, and then when the cooling operation is resumed, the liquid refrigerant stored in the outdoor heat exchanger 5 is Therefore, it flows at a stroke toward the indoor heat exchanger 3 having a small volume. Thus, the refrigerant that has not evaporated in the indoor heat exchanger 3 among the refrigerant that has flowed to the indoor heat exchanger 3 side reaches the compressor 2, so that liquid compression is likely to occur in the compressor 2.

  The present inventors can further improve the reliability of the air conditioner 1 by appealing the range of the refrigerant amount of R32 that does not cause liquid compression even under such condition 1 where liquid compression is likely to occur. We focused on what we can do. Therefore, in particular, representative results related to the condition 1 are extracted from the experimental results shown in FIG. 4 and shown in the graphs of FIGS.

  5 and 6, the horizontal axis represents the refrigerant amount (g) of the entire refrigeration cycle / the total volume (L) of the entire refrigeration cycle, and the vertical axis represents the refrigerant amount (g) of the entire refrigeration cycle / outdoor heat exchanger 5. The volume (L) is taken. Here, in the vertical axis | shaft of FIG. 5, 6, the volume of the outdoor heat exchanger 5 is extracted instead of the total volume of the whole refrigerating cycle. As described above, since the volume of the outdoor heat exchanger 5 is larger than that of the indoor heat exchanger 3 and greatly affects the frequency of occurrence of liquid compression, attention should be paid to the volume of the outdoor heat exchanger 5 in the refrigeration cycle. Thus, the relationship between the refrigerant amount of R32 and the occurrence of liquid compression can be grasped more accurately.

  5 and 6, as described above, the refrigerant amount / total volume of the entire refrigeration cycle is preferably in the range of 200 to 300 g / L when the capacity class is less than 4 kW (FIG. 5). In the case of 4 kW or more (FIG. 6), it can be seen that the range of 250-350 g / L is preferable. On the other hand, focusing on the vertical axis of FIGS. 5 and 6, when the capacity class is less than 4 kW (FIG. 5), the value of the refrigerant amount of the entire refrigeration cycle / the volume of the outdoor heat exchanger 5 is 750-1100 g / When the range of L is preferable and the capacity class is 4 kW or more (FIG. 6), the value of the refrigerant amount of the entire refrigeration cycle / the volume of the outdoor heat exchanger 5 is preferably in the range of 750 to 1200 g / L. Recognize. That is, in such a range, since the phenomenon of liquid compression can be suppressed even under the severe condition of Condition 1, the liquid compression is more reliably suppressed and the reliability of the air conditioner 1 is improved. Can do.

  It is to be noted that, by appropriately combining arbitrary embodiments of the various embodiments described above, the effects possessed by them can be produced.

  INDUSTRIAL APPLICABILITY The present invention can suppress the occurrence of liquid compression during unsteady operation in a compressor and improve the reliability of an air conditioner. Therefore, the present invention is applied to various air conditioners including home use and business use. be able to.

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Compressor 3 Indoor heat exchanger 4 Expansion means 5 Outdoor heat exchanger 6 Switching valve 7 Accumulator 8 1st piping 9 2nd piping 10 3rd piping 11 4th piping 12 5th piping 13 Sixth piping 14 Seventh piping

Claims (4)

In a refrigeration cycle including a compressor, an indoor heat exchanger, expansion means, and an outdoor heat exchanger, an air conditioner using R32 as a refrigerant to be circulated,
An air conditioner in which the capacity class of the air conditioner is less than 4 kW, and the filling amount of R32 for the refrigeration cycle is in the range of 200 to 300 g per liter of the total volume of the refrigeration cycle. In a refrigeration cycle including a compressor, an indoor heat exchanger, expansion means, and an outdoor heat exchanger, an air conditioner using R32 as a refrigerant to be circulated,
An air conditioner in which the capacity class of the air conditioner is 4 kW or more, and the filling amount of R32 for the refrigeration cycle is within a range of 250 to 350 g per liter of the total volume of the refrigeration cycle.   The air conditioner according to claim 1, wherein a filling amount of R32 with respect to the refrigeration cycle is within a range of 750 g to 1100 g per liter of the outdoor heat exchanger.   The air conditioner according to claim 2, wherein a filling amount of R32 with respect to the refrigeration cycle is within a range of 750 g to 1200 g per liter of the outdoor heat exchanger.

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