JP2015197254A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle device capable of preventing global warming while securing desired refrigeration capacity and equipment efficiency.SOLUTION: A refrigeration cycle device has a compressor, an outdoor heat exchanger, a pressure reduction valve, and an indoor heat exchanger. The compressor, the outdoor heat exchanger, the pressure reduction valve and the indoor heat exchanger are successively connected to a refrigerant circuit filled with a working fluid of GWP of 600 or less. The working fluid is composed of a single refrigerant or a mixed refrigerant. GWP of the working fluid is GWP. A product of a length in a horizontal direction and a length in a height direction, of the outdoor heat exchanger is a front face area, and a charging amount Ma (kg/m) of the working fluid per 1 mof the front face area is set to be 0.48 times or more and 1.8 times or less of a peak filling amount M (kg/m) calculated by a formula (1).

Description

  Embodiments described herein relate generally to a refrigeration cycle apparatus.

  In a refrigeration cycle apparatus such as an air conditioner, a refrigerant with a lower global warming potential (GWP) than a currently used HFC refrigerant such as R410A is used from the viewpoint of preventing global warming. Is being considered.

  Here, in order to prevent global warming, it is necessary to secure desired refrigeration capacity and equipment efficiency (COP (coefficient of performance), APF (year-round energy consumption efficiency), etc.) after using a refrigerant with low GWP. is there. That is, when the refrigerant having a low GWP is used and the refrigeration capacity and equipment efficiency of the refrigeration cycle apparatus are significantly reduced, it is necessary to increase the amount of electric power in order to maintain the same performance as before. . In this case, the amount of carbon dioxide emissions when using electricity increases, which may not be an effective measure to prevent global warming.

JP 2001-194016 A

  The problem to be solved by the present invention is to provide a refrigeration cycle apparatus capable of preventing global warming while ensuring desired refrigeration capacity and equipment efficiency.

The refrigeration cycle apparatus of the embodiment includes a compressor, an outdoor heat exchanger, a pressure reducing valve, and an indoor heat exchanger. The compressor, the outdoor heat exchanger, the pressure reducing valve, and the indoor heat exchanger are sequentially connected to a refrigerant circuit filled with a working fluid having a GWP of 600 or less. The working fluid consists of a single refrigerant or a mixed refrigerant. The GWP of the working fluid is GWP ₁ . The front area is defined as the product of the length in the horizontal direction and the length in the height direction of the outdoor heat exchanger. The working fluid filling amount Ma (kg / m ² ) per 1 m ^{2 of} the front surface area is not less than 0.48 times the peak filling amount M (kg / m ² ) calculated by the following equation (1) and 1.8. It is set to less than double.

The schematic block diagram of the refrigerating-cycle apparatus in embodiment. The Mollier diagram which shows the refrigerating cycle of the refrigerating-cycle apparatus in embodiment. The front view of the outdoor heat exchanger in embodiment. The graph which shows the filling amount per 1 m < ² > front surface area of the outdoor heat exchanger with respect to GWP.

Hereinafter, the refrigeration cycle apparatus of the embodiment will be described with reference to the drawings.
As shown in FIG. 1, a refrigeration cycle apparatus 1 according to this embodiment includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, a pressure reducing valve 5, and an indoor heat exchanger 6 that are sequentially connected by a refrigerant circuit 7. It is configured. Of these components, the compressor 2, the four-way valve 3, the outdoor heat exchanger 4, and the pressure reducing valve 5 are accommodated in the outdoor unit 11, and the indoor heat exchanger 6 is accommodated in the indoor unit 12. Yes. Moreover, in the example shown in FIG. 1, the solid line arrow shows the flow direction of the refrigerant | coolant at the time of cooling, and the broken line arrow at the time of heating.

In such a refrigeration cycle apparatus 1, a cooling operation or a heating operation is performed by changing the flow of the refrigerant by the four-way valve 3. For example, in the cooling operation, the compressor 2, the four-way valve 3, the outdoor heat exchanger 4, the pressure reducing valve 5, and the indoor heat exchanger 6 are connected in order. At this time, the outdoor heat exchanger 4 is made to function as a condenser, the indoor heat exchanger 6 is made to function as an evaporator, and the room is cooled.
On the other hand, in the heating operation, the compressor 2, the four-way valve 3, the indoor heat exchanger 6, the pressure reducing valve 5, and the outdoor heat exchanger 4 are connected in order. At this time, the indoor heat exchanger 6 is caused to function as a condenser, and the outdoor heat exchanger 4 is caused to function as an evaporator, thereby heating the room.

The above-described refrigeration cycle will be described with reference to a Mollier diagram (ph diagram) shown in FIG.
The section from point A to point B shown in FIG. 2 is a step in which the refrigerant is compressed by the compressor 2, and compresses the low-pressure gas refrigerant taken into the compressor 2 to compress the high-temperature / high-pressure gas refrigerant. And The section from point B to point C is a process of heat exchange between the refrigerant in the condenser of the heat exchangers 4 and 6 and the air passing through the condenser, and the high temperature and high pressure fed from the compressor 2. Heat is dissipated from the gas refrigerant to convert the high-temperature and high-pressure gas refrigerant into a high-pressure liquid refrigerant. The section from point C to point D is a step in which the refrigerant is depressurized by the pressure reducing valve 5, and the pressure of the high-pressure liquid refrigerant sent from the condenser in the heat exchangers 4 and 6 is lowered to reduce the high-pressure liquid refrigerant. Use a low-temperature, low-pressure gas-liquid two-phase refrigerant. The section from point D to point A is a process of heat exchange between the refrigerant in the evaporator of the heat exchangers 4 and 6 and the air passing through the evaporator, and the low temperature and low pressure fed from the pressure reducing valve 5 The refrigerant in the gas-liquid two-phase state absorbs heat, and the low-temperature and low-pressure gas-liquid two-phase refrigerant is converted into a low-pressure gas refrigerant.

  FIG. 3 shows an outdoor heat exchanger 4 composed of a fin-and-tube heat exchanger. The outdoor heat exchanger 4 includes a plurality of fins 21 stacked at intervals, a pair of end plates 22 that sandwich the fins 21 from both sides in the stacking direction, and the fins 21 and the end plates 22 in the stacking direction. And a heat exchange tube 23 (refrigerant circuit 7) through which the refrigerant flows. The outdoor heat exchanger 4 is not limited to a fin-and-tube heat exchanger, and may be, for example, a parallel flow heat exchanger having a flat tube with a divided internal flow path and a header.

In the illustrated example, each fin 21 is made of a material having excellent thermal conductivity such as aluminum. In the outdoor heat exchanger 4, air passes through the gaps between the fins 21.
The end plate 22 is made of a material having higher rigidity than the fins 21. Note that the end plates 22 may be made of the same material as the fins 21 as long as the end plates 22 are positioned on both sides in the stacking direction of the fins 21 and sandwich the fins 21.

  The heat exchange tube 23 is made of a material having excellent thermal conductivity, such as copper. The heat exchange tube 23 penetrates the fin 21 and the end plate 22 in the stacking direction, and is folded back outside the end plate 22. Thereby, the heat exchange tube 23 extends in the height direction (extending direction) of the fins 21 and the end plates 22 while meandering in a plurality of stages in the thickness direction of the fins 21 and the end plates 22. .

In the refrigeration cycle apparatus 1 of the present embodiment, the refrigerant circuit 7 has a GWP of 600 or less as a working fluid and is filled with a refrigerant composed of a single refrigerant or a mixed refrigerant. In addition, GWP is a number showing how much other greenhouse gases have the ability to warm based on CO ₂ . That is, when a unit mass (for example, 1 kg) of greenhouse gas is released into the atmosphere, the integrated value of radiant energy given to the earth within a certain time (for example, 100 years) (ie, the impact on global warming) , Estimated as a ratio to CO ₂ .

  As the above-described refrigerant, in this embodiment, a single refrigerant of HFO-1234yf, a mixed refrigerant of HFO-1234yf and R32, a single refrigerant of HFO-1234ze, a mixed refrigerant of HFO-1234ze and R32, or the like. Preferably used. The GFO of HFO-1234yf is “4”, the GWP of HFO-1234ze is “6”, and the GWP of R32 is “675”.

  In the mixed refrigerant of HFO-1234yf and R32, the relationship between the mixing ratio (concentration) and GWP is as shown in Table 1.

  Further, in the mixed refrigerant of HFO-1234ze and R32, the relationship between the mixing ratio (concentration) and GWP is as shown in Table 2.

Here, the inventor of the present application firstly obtains a desired refrigeration capacity in the refrigeration cycle apparatus 1 of the present embodiment, and an optimum filling amount (hereinafter, peak filling amount M (kg / m ² )) that can ensure high equipment efficiency. Called). Specifically, the peak filling amount M has the same refrigeration capacity as that of a refrigeration cycle apparatus (comparative example) using a refrigerant of R410A (GWP 2090) having a GWP larger than 600 that is generally used at present, and In the ph diagram shown in FIG. 2, when the degree of supercooling h1 and the degree of superheat h2 are set to be equivalent to those of the refrigeration cycle apparatus of the comparative example, the filling amount can ensure high equipment efficiency.

  Further, the set values of the degree of supercooling h1 and the degree of superheat h2 described above are as shown in Table 3.

Under these conditions, the peak filling amount M per 1 m ² of the front surface area S of the outdoor heat exchanger 4 is obtained for a plurality of types of refrigerants having different GWPs. As a result, the solid line shown in the graph of FIG. 4 is obtained. It was. In addition, in the outdoor heat exchanger 4 shown in FIG. 2, the front surface area S is the distance between the pair of end plates 22 that is the length in the horizontal direction L, and the fin 21 (end plate that is the length in the height direction). 22) is a product (S = L × H) where H is the height (air passage area). In this case, the front surface area S is adjusted by adjusting the distance L according to the number of the laminated fins 21 in the outdoor heat exchanger 4 and adjusting the height H according to the number of stages of the heat exchange tubes 23. be able to.

Further, the peak filling amount M shown in the graph of FIG. 4 is expressed by the following equation (1), where GWP of the refrigerant to be used is GWP ₁ . Note that “2090” in the following formula (1) is the G410 of R410A used as a comparative example.

Thus, it can be seen that the GWP and the peak filling amount M per 1 m ^{2 of the} front surface area S have a correlation. That is, it can be seen that the peak filling amount M decreases as the GWP increases.

Next, the inventor of the present application has set a filling amount Ma (kg / m ² ) within a range in which a desired refrigeration capacity and device efficiency can be secured at a minimum with respect to the peak filling amount M described above. Specifically, the filling amount Ma is preferably set in a range of 0.48 times or more and 1.8 times or less of the peak filling amount M (a chain line range in FIG. 4). It is more preferable to set to a range that is twice or less (the dashed line range in FIG. 4).

When the filling amount Ma is increased or decreased with respect to the peak filling amount M, the refrigerating capacity and the equipment efficiency also tend to decrease.
Specifically, by setting the filling amount Ma to 0.9 times or more (Ma ≧ 0.9M) of the peak filling amount M (Ma ≧ 0.9M), the refrigeration capacity is ensured to be equal to the peak filling amount M, and the equipment Even in the efficiency (COP), an efficiency of 97% or more with respect to the peak filling amount M could be secured. Since COP has a correlation with APF, APF also increases or decreases as COP increases or decreases.
In addition, when the filling amount Ma is 0.48 times or more and less than 0.9 times the peak filling amount M (0.9M> Ma ≧ 0.48M), a desired capacity can be secured for the refrigeration capacity. Equipment efficiency decreased slightly (less than 97%).

On the other hand, when the filling amount Ma is less than 0.48 times the peak filling amount M (Ma <0.48M), the refrigerating capacity may not be ensured due to a significant decrease in refrigerant latent heat. In addition, when the filling amount Ma is less than 0.48 times the peak filling amount M (Ma <0.48M), the degree of superheat to the compressor 2 increases, and the reliability of the compressor 2 may be impaired. there were.
From such a result, in order to ensure the refrigerating capacity and the reliability of the compressor 2, the lower limit of the filling amount Ma in this embodiment is set to 0.48 times or more with respect to the peak filling amount M, and the equipment In order to ensure efficiency, it is preferable to set the peak filling amount M to 0.9 times or more.

Further, when the filling amount Ma is 1.2 times or less of the peak filling amount M (Ma ≦ 1.2M), the refrigerating capacity is ensured to be equal to that of the peak filling amount M, and the peak filling amount is also obtained in terms of equipment efficiency. The efficiency of 97% or more was ensured with respect to M.
Furthermore, when the filling amount Ma is set to be larger than 1.2 times the peak filling amount M and not more than 1.8 times (1.2M <Ma ≦ 1.8M), the refrigerating capacity can secure a desired capacity. The equipment efficiency decreased slightly.

On the other hand, when the filling amount Ma is larger than 1.8 times the peak filling amount M, the effective heat transfer area decreases in the heat exchangers 4 and 6 functioning as a condenser (decrease in condensation heat transfer performance). I will. As a result, the discharge pressure increases, and the reliability of the device (compressor 2 or the like) may be impaired.
From these results, the upper limit of the filling amount Ma in the present embodiment is set to 1.2 times or less with respect to the peak filling amount M in order to ensure the equipment efficiency, in order to ensure the reliability of the equipment. Is preferably set to 1.8 times or less.

As described above, in this embodiment, the filling amount Ma per 1 m ^{2 of the} front surface area S is set to 0.48 times or more and 1.8 times or less of the peak filling amount M calculated by the above-described equation (1). The configuration.
According to this configuration, since it is possible to achieve low GWP while ensuring the desired refrigeration capacity and device reliability, it is possible to reduce the impact on global warming and reduce the environmental load.

  Furthermore, in the present embodiment, by setting the filling amount Ma in the range of 0.9 times or more and 1.2 times or less of the peak filling amount M, it is possible to secure desired equipment efficiency while achieving low GWP. .

  In addition, although embodiment mentioned above demonstrated the case where HFO-1234yf, HFO-1234ze, and R32 were used as a refrigerant | coolant, it is not restricted to this. That is, if the GWP is 600 or less, the type of refrigerant, such as a single refrigerant or a mixed refrigerant, can be changed as appropriate.

Furthermore, in the above-described embodiment, the case where the range of the filling amount Ma is expressed with respect to the peak filling amount M per 1 m ^{2 of the} front surface area S has been described. However, the filling amount may be set based on other conditions. Absent. For example, the refrigerant charging amount Mb (g / kW) per refrigeration capacity 1 kW of the refrigeration cycle apparatus 1 may be set in the range of the following equation (2).

  Further, the refrigerant charging amount Mc (g / L) per 1 L of the internal volume of the outdoor heat exchanger 4 of the refrigeration cycle apparatus 1 may be set in the range of the following equation (3).

  Even if it is a case where it sets to the range of Formula (2) and (3) mentioned above, while using a refrigerant | coolant with low GWP, while ensuring desired refrigeration capacity, the reliability of an apparatus can be ensured.

According to at least one embodiment described above, the refrigerant charging amount Ma (kg / m ² ) per 1 m ² of the front surface area of the outdoor heat exchanger is calculated by the above-described equation (1). Since it is set to 0.48 times or more and 1.8 times or less of the above, it is possible to achieve low GWP while ensuring the desired refrigeration capacity and reliability of the equipment, so the impact on global warming The environmental load can be reduced.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Refrigeration cycle apparatus, 2 ... Compressor, 4 ... Outdoor heat exchanger, 5 ... Pressure reducing valve, 6 ... Outdoor heat exchanger

Claims (2)

In a refrigeration cycle apparatus in which a working fluid having a GWP of 600 or less is filled in a refrigerant circuit in which a compressor, an outdoor heat exchanger, a pressure reducing valve, and an indoor heat exchanger are sequentially connected.
The working fluid consists of a single refrigerant or a mixed refrigerant,
When the GWP of the working fluid is GWP ₁ and the product of the length in the horizontal direction and the length in the height direction of the outdoor heat exchanger is defined as the front area,
The working fluid filling amount Ma (kg / m ² ) per 1 m ^{2 of the} front surface area is not less than 0.48 times the peak filling amount M (kg / m ² ) calculated by the following equation (1) and 1.8. A refrigeration cycle device that is set to double or less.

^2. The refrigeration cycle apparatus according to claim 1, wherein the filling amount Ma (kg / m ² ) is set to be 0.9 to 1.2 times the peak filling amount M (kg / m ² ).

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