JP2015111012A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle device capable of effectively preventing global warming and ensuring safety and low cost.SOLUTION: A refrigeration cycle device includes a refrigeration cycle in which a hermetic compressor, a condenser, an expansion device, and an evaporator are coupled together by a refrigerant tube, and in which R410A refrigerant is filled. The condenser is formed out of a parallel flow heat exchanger, and a filling amount of the R410A refrigerant is set in a range from 80 g to 130 g per refrigeration capacity of 1 kW.

Description

  Embodiments described herein relate generally to a refrigeration cycle apparatus.

  Conventionally, R410A refrigerant has been widely used as a refrigerant in a refrigeration cycle apparatus (Patent Document 1). R410A refrigerant has an ozone depletion potential (ODP) of 0 (zero) as its properties, and is low in toxicity and nonflammable. In addition, it has excellent heat transfer capability and high cycle efficiency, and has a slightly large global warming potential (GWP) of about 2090.

  Further, as a refrigerant whose GWP is smaller than the R410A refrigerant, there is an R32 refrigerant (GWP is about 650). However, R32 refrigerant has low toxicity but slightly flammability. Therefore, it is necessary to take an explosion-proof measure for the equipment, and the cost increases.

Further, there is a CO ₂ refrigerant (GWP = 1) as a refrigerant having ODP of 0, low toxicity and nonflammability, and extremely low GWP. However, when CO ₂ refrigerant is used, the operating pressure is high, so the system cost for securing the strength is high, and the cycle efficiency is low. To increase the cycle efficiency, an auxiliary machine such as an expander is required. There is a problem that it becomes necessary and costs further increase.

JP 2001-194016 A

  The problem to be solved by the present invention is to provide a safe and low-cost refrigeration cycle apparatus that is effective in preventing global warming.

  According to the refrigeration cycle apparatus of this embodiment, the hermetic compressor, the condenser, the expansion device, and the evaporator are connected by the refrigerant pipe, and the refrigeration cycle in which the R410A refrigerant is sealed is provided.

  In addition, the condenser was formed by a parallel flow heat exchanger, and the amount of R410A refrigerant sealed was in the range of 80 g to 130 g per kW of refrigeration capacity.

Shows the relative relationship between the filling amount of refrigerating capacity 1kW per R410A refrigerant in the refrigeration cycle apparatus according to the present embodiment, LCCP ratio of R410A refrigerant relative to CO ₂ refrigerant (R410A / CO _2). The figure which shows the refrigerating cycle which comprised the twin rotary type sealed compressor of the refrigerating-cycle apparatus which concerns on this embodiment, and this compressor. The partially cutaway front view of the condenser formed with the parallel flow type heat exchanger shown in FIG. The partial expansion perspective view of the condenser formed with the parallel flow type heat exchanger shown in FIG. The figure which shows the relative relationship of the operation time of the twin rotary type hermetic compressor shown in FIG. 2, and the amount of wear of a roller outer peripheral part.

  Hereinafter, the refrigeration cycle apparatus of the present embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent part in several drawing.

  FIG. 2 is a view showing a twin rotary type hermetic compressor of the refrigeration cycle apparatus according to the present embodiment and a refrigeration cycle equipped with the compressor. As shown in FIG. 2, the refrigeration cycle apparatus 1 includes a twin rotary type hermetic compressor 2, a condenser 3 formed by a parallel flow type heat exchanger, an expansion device 4, an evaporator 5, and an accumulator 6. 7, a refrigerating cycle 8 in which R410A refrigerant is enclosed and circulated in the direction of the arrow in the figure is configured.

  The hermetic compressor 2 is a compressor that discharges and fills a high-pressure gaseous refrigerant into a metal hermetic case 9, and an electric motor unit 10 is disposed in the upper part of the hermetic case 9. A twin rotary type compression mechanism 11 is disposed below. A lubricating oil reservoir O is formed at the inner bottom of the sealed case 9.

  The electric motor unit 10 is press-fitted into the sealed case 9 and is fixed in a state where the outer peripheral surface is in close contact with the inner surface of the sealed case 9, and a rotor 13 rotatably disposed inside the stator 12. It is composed of Further, the electric motor unit 10 is configured as a permanent magnet type electric motor including a rotor 13 and a permanent magnet formed of a rare earth magnet containing neodymium or samarium.

  The stator 12 is electrically connected to the hermetic compressor 2 power supply terminal 14, and this power supply terminal 14 is electrically connected to the inverter 15. The inverter 15 receives a control signal from a control device (not shown) and controls the compression frequency of the compression mechanism unit 11 by appropriately controlling the operating frequency of the motor unit 10. The hermetic compressor 2 has an excluded volume so that the operating frequency when the refrigeration cycle apparatus 1 exhibits the rated capacity is higher than the commercial power supply frequency (50/60 Hz) (for example, 90 Hz). Is set.

  The rotor 13 has a rotating shaft 16 inserted concentrically and fixed to the center thereof. The compression mechanism unit 11 includes a first cylinder 18 in the figure and a second cylinder 19 in the figure in the lower part of the rotary shaft 16 disposed above and below via an intermediate partition plate 17. . A main bearing 20 is superimposed on the upper surface of the first cylinder 18 and is fixedly attached to the first cylinder 18 via a first mounting bolt 21a. The sub bearing 22 is overlapped on the lower surface portion of the second cylinder 19 and is fixedly attached to the first cylinder 18 via the second mounting bolt 21b.

  On the other hand, the rotary shaft 16 is pivotally supported by the main bearing 20 and the sub-bearing 22 at its midway portion and lower end portion. Further, the rotary shaft 16 penetrates through the insides of the first and second cylinders 18 and 19, and is integrally provided with first and second eccentric portions 16a and 16b formed with a phase difference of about 180 °. The first and second eccentric portions 16a and 16b have the same diameter, and are assembled so as to be positioned at the inner diameter portions of the first and second cylinders 18 and 19, respectively. First and second eccentric rollers 23a and 23b having the same diameter are fitted to the outer peripheral surfaces of the first and second eccentric portions 16a and 16b.

  The upper and lower surfaces of the first cylinder 18 are partitioned by the main bearing 20 and the intermediate partition plate 17, and a first cylinder chamber 18a is formed inside. The upper and lower surfaces of the second cylinder 19 are partitioned by the intermediate partition plate 17 and the auxiliary bearing 22, and a second cylinder chamber 19a is formed inside. The cylinder chambers 18a and 19a are formed to have the same diameter and height, and the first and second eccentric rollers 23a and 23b are accommodated so as to be eccentrically rotatable.

  Each eccentric roller 23a, 23b is formed of, for example, Monicro cast iron, which is Ni—Cr—Mo flake graphite alloy cast iron having a hardness of HRC53-55, and the height dimension thereof is the same as the height dimension of each cylinder chamber 18a, 19a. It is formed substantially the same. Therefore, each cylinder chamber 18a, 19a is set to the same excluded volume. Each cylinder 18, 19 is provided with blade chambers 24a, 24b communicating with the cylinder chambers 18a, 19a. In each of the blade chambers 24a and 24b, the first and second blades 25a and 25b are accommodated so as to protrude and retract with respect to the first and second cylinder chambers 18a and 19a.

  The first and second blades 25a and 25b are made of, for example, DLC (Diamond Like Carbon) coding on the outer surface of a high-speed tool steel having a base material hardness of HRC60 or higher, or by nitriding stainless steel Consists of increased hardness. The first and second blades 25a and 25b are formed so that their tip portions are semicircular in plan view, and project into the first and second cylinder chambers 18a and 19a facing each other. The linear contact can be made with the peripheral walls of the second eccentric rollers 23a and 23b regardless of the rotation angle. When the eccentric rollers 23a and 23b rotate eccentrically, the tips of the blades 25a and 25b are in sliding contact with the peripheral walls of the eccentric rollers 23a and 23b.

  The hermetic compressor 2 is provided with a discharge pipe 26 at the upper end of the hermetic case 9. The discharge pipe 26 is connected to one end of the refrigerant pipe 7, and the other end of the refrigerant pipe 7 is connected to the upper end portion of the accumulator 6. The accumulator 6 is connected to the compressor 1 via first and second suction pipes 27a and 27b. Thereby, the refrigeration cycle 8 is configured.

  The first and second suction pipes 27a and 27b pass through the sealed case 9 of the compressor 2 and communicate with the suction ports of the first and second cylinder chambers 18a and 19a.

  The refrigerant compressed in the first and second cylinder chambers 18a, 19a opens the discharge ports by opening the discharge valves 18b, 19b. Thereby, the compressed refrigerant is discharged into the sealed case 9 from each discharge port, and is filled in the sealed case 9. The refrigerant gas filled in the sealed case 9 is discharged from the discharge pipe 26 through the refrigerant pipe 7 to the condenser 3 side composed of a parallel flow type heat exchanger.

  As shown in FIGS. 3 and 4, the condenser 3 composed of a parallel flow type heat exchanger is almost entirely made of aluminum or an aluminum alloy, and is opposed to each other with a required interval in the left-right direction in the drawings. A pair of header pipes 3a and 3b is provided. Further, between the header pipes 3a and 3b, a plurality of flat heat exchange tubes 3c, 3c,... Installed (connected) in the horizontal direction are arranged substantially parallel to each other with a predetermined interval in the vertical direction in the figure. A plurality of corrugated fins 3d, 3d,... Are interposed between the plurality of heat exchange tubes 3c, 3c,.

  As shown in FIG. 4, each heat exchange tube 3c is formed with a plurality of divided heat medium flow paths 3ca,. Further, side plates 3e, 3e,... Are brazed to the upper outer side and the lower outer side of the upper and lower corrugated fins 3d, respectively. Further, end caps 3f are brazed to both upper and lower opening ends in the axial direction of the header pipes 3a and 3b.

  And in this refrigeration cycle 8, as a refrigerant, R410A refrigerant is enclosed in the range of 80g-130g per 1kW of refrigerating capacity.

  Next, the operation of the refrigeration cycle apparatus 1 configured as described above will be described.

  A control unit (not shown) gives the inverter 15 a control signal for operating the hermetic compressor 2. The inverter 15 operates the hermetic compressor 2 at the operation frequency commanded by this control signal.

  Thereby, the rotating shaft 16 of the electric motor unit 10 is rotationally driven, and the first and second eccentric rollers 23a and 23b rotate eccentrically in the first and second cylinder chambers 18a and 19a.

  In the first cylinder 18, since the first blade 25a is always elastically pressed and biased toward the first eccentric roller 23a by the spring member, the tip edge of the first blade 25a has the first eccentricity. The first cylinder chamber 18a is slid into a suction chamber and a compression chamber in sliding contact with the outer peripheral wall of the roller 23a.

  The space capacity of the first cylinder chamber 18a in a state where the inner circumferential surface rolling contact position of the first eccentric roller 23a coincides with the storage groove of the first blade 25a and the first blade 25a is most retracted. Is the maximum. For this reason, the refrigerant gas is sucked into the first cylinder chamber 18a from the accumulator 6 through the first suction pipe 27a to be filled. Here, with the eccentric rotation of the first eccentric roller 23a, the rolling contact position with respect to the inner peripheral surface of the first cylinder chamber 18a moves, and the volume of the compression chamber partitioned by the first cylinder chamber 18a decreases. To do. That is, the refrigerant gas introduced into the first cylinder chamber 18a is gradually compressed.

  Further, when the rotary shaft 16 is continuously rotated, the capacity of the compression chamber of the first cylinder chamber 18a is further reduced and the refrigerant gas is compressed, and when the pressure rises to a predetermined pressure, the first discharge valve 18b is caused by the pressure. The valve opens and the discharge port opens. For this purpose, the high-pressure gas is discharged into the sealed case 9 via the valve cover.

  On the other hand, on the second cylinder 19 side, the high-pressure refrigerant gas compressed in the second cylinder chamber 19a is discharged into the sealed case 9 from the second discharge port by substantially the same action as the first cylinder 18. Charged.

  Then, the high-pressure gas filled in the sealed case 9 is introduced into the parallel flow type condenser 3 through the discharge pipe 26 and the refrigerant pipe 7, where it is condensed and liquefied, and further adiabatically expanded by the expansion device 4. It evaporates in the evaporator 5 and takes the latent heat of evaporation from the heat exchange air to cool it. The evaporated refrigerant is introduced into the accumulator 6, where it is separated into gas and liquid, and is again sucked into the compression mechanism 11 from the first and second suction pipes 27a and 27b, and the above action is repeated. Circulate the refrigeration cycle 8.

FIG. 1 shows the LCCP ratio, which is the ratio between the LCCP (Life Cycle Climate Performance) of the refrigeration cycle apparatus using CO ₂ refrigerant and the LCCP of the refrigeration cycle apparatus using R410A refrigerant, and the charging of the R410A refrigerant When the LCCP ratio is smaller than 1, the LCCP of the refrigeration cycle apparatus using the R410A refrigerant is smaller than the LCCP of the refrigeration cycle apparatus using the CO ₂ refrigerant. This is effective for preventing global warming.

LCCP is an index for the prevention of global warming, and includes TEWI (Total Equivalent Warming Impact), energy consumption (indirect impact) during the production of greenhouse gases used, and leakage to outside air ( It is a numerical value to which (direct influence) is added, and the unit is kg-CO ₂ . TEWI is the sum of direct and indirect effects calculated respectively by a required mathematical formula.

LCCP is calculated by the following relational expression.
[Equation 1]
LCCP = GWP ^RM × W + GWP × W × (1-R) + N × Q × A
Here, GWP ^RM : Warming effect related to refrigerant production, W: Refrigerant filling amount, R: Refrigerant recovery amount at the time of equipment disposal, N: Equipment usage period (year), Q: CO ₂ emission intensity, A: Annual In this embodiment, (1−R) = 0.7, N = 12 [year], and Q = 0.378 [kgCO ₂ / kWh].

In this refrigeration cycle apparatus 1, a parallel flow type heat exchanger is used as the condenser 3, an R410A refrigerant is used as the refrigerant, and the filling amount (encapsulation amount) is within a range of 80 g to 130 g per kW of the refrigeration capacity. Therefore, the LCCP ratio (R410A / CO ₂ ) to LCCP of the refrigeration cycle apparatus using the CO ₂ refrigerant can be made smaller than 1 as shown in FIG. That is, it can be seen that the refrigeration cycle apparatus 1 of the present embodiment using the R410A refrigerant can make the LCCP smaller than the refrigeration cycle apparatus using the CO ₂ refrigerant and is more effective in preventing global warming.

In addition, LCCP of the refrigeration cycle apparatus using CO ₂ is a case where an auxiliary machine such as an expander is used, and a result obtained by trial calculation using the highest system efficiency conceivable at the present time is used.

The present inventor conducted research and development to improve LCCP using CO ₂ (GWP = 1), which has ODP = 0, low toxicity and nonflammability, extremely low GWP, and could be a substitute for R410A refrigerant.

However, when CO ₂ is used as a refrigerant, the operating pressure becomes high, the system cost becomes high, and the cycle efficiency is low. Therefore, in order to increase the cycle efficiency, an auxiliary machine such as an expander is required. There was a further increase in costs. In addition, as this auxiliary machine, there exists a thing which rotates a turbine with the pressure reduction loss energy at the time of pressure reduction of a refrigerant | coolant, and adds the rotational force to the rotational force of the compressor 2, for example.

On the other hand, when the parallel flow type heat exchanger is used as the condenser 3, the heat passage rate is higher than that of a general cross fin type heat exchanger and the ventilation resistance is low. Capability can be expanded. Therefore, the amount of filled refrigerant per unit refrigeration capacity can be reduced. For this reason, it has been found that even when the R410A refrigerant having a slightly higher GWP is used, the LCCP can be suppressed lower than when the CO ₂ refrigerant having low cycle efficiency is used.

In addition, the LCCP of the refrigeration cycle apparatus using the R410A refrigerant has a large LCCP due to a deterioration in cycle efficiency due to a shortage of refrigerant if the charging amount is too small, and further, the influence of GWP becomes high if the charging amount is too large. , LCCP increases. On the other hand, by being within the range of 80 g to 130 g / kW, the LCCP can be suppressed lower than the case of using the CO ₂ refrigerant even when the R410A refrigerant is used, and it is effective in preventing global warming. In addition, a refrigeration cycle apparatus that is low in cost and safe can be obtained.

  And since the parallel flow type heat exchanger which is the condenser 3 is substantially all made of all aluminum made of aluminum or an aluminum alloy, the internal volume of the condenser 3 is reduced without sacrificing the condensation performance. Can be reduced in size and weight.

  The refrigeration cycle apparatus 1 has a frequency (for example, about 90 Hz) where the operating frequency of the hermetic compressor 2 when the refrigeration cycle apparatus 1 exhibits the rated capacity is higher than the commercial power supply frequency (for example, 50/60 Hz). Therefore, the motor torque per rotation of the rotating shaft 16 of the electric motor unit 10 of the hermetic compressor 2 can be reduced. For this reason, it is possible to reduce the size and weight by reducing the diameter of the electric motor unit 10. Further, for this purpose, the internal volume in the sealed case 9 can be reduced, so that the refrigerant charging amount can be further reduced.

  Further, according to the refrigeration cycle apparatus 1, since the rare-earth magnet containing neodymium or samarium having a strong magnetic force is used as the permanent magnet of the rotor 13 of the permanent magnet type electric motor unit 10, it is possible to reduce the size and increase the output. Is possible. For this reason, it is possible to reduce the size of the electric motor unit 10 and to reduce the internal volume of the sealed case 9 that accommodates the electric motor unit 10, thereby reducing the amount of refrigerant filling (filling amount). Can be achieved.

  In general, when the compression mechanism unit 11 is a rotary type, if the operating frequency of the hermetic compressor 2 when the refrigeration cycle apparatus 1 exhibits the rated capacity is increased, the sliding between the eccentric rollers 23a and 23b and the blades 25a and 25b is increased. The slidability deteriorates on the contact surface, and wear tends to proceed particularly at the outer peripheral portions of the eccentric rollers 23a and 23b.

  FIG. 5 shows the relative wear amount of the outer peripheral portions of the first and second eccentric rollers 23a and 23b and the operation time when the compression mechanism unit 11 is operated at an operation frequency of 90 Hz to 120 Hz higher than the commercial power supply frequency. The relationship is shown by comparing the present embodiment with a comparative example.

  In FIG. 5, in the comparative example, the first and second blades 25a and 25b are formed by subjecting stainless steel as a base material to nitriding treatment, while the first and second eccentric rollers 23a and 23b are formed with hardness. The case where it comprises with HRC50 monikuro cast iron is shown.

  In the first embodiment, the first and second blades 25a and 25b are formed by applying DLC coating to a high-speed tool steel having a base material hardness of HRC60 or higher. The case where the rollers 23a and 23b are made of monichro cast iron having a hardness HRC50 is shown.

  Furthermore, in the second embodiment, the first and second blades 25a and 25b are formed in the same manner as in the comparative example, while the first and second eccentric rollers 23a and 23b have a hardness of HRC53 (54 ± 1) or more. It shows the case where it is formed from the cast iron cast iron.

  In FIG. 5, a straight line B indicates a wear limit that can ensure the characteristics of the compression mechanism unit 11, and the outer wear amount of the first and second eccentric rollers 23 a and 23 b is greater than the wear limit B. It is necessary to be small.

  As shown in FIG. 5, in the comparative example, the outer peripheral wear amount of the first and second eccentric rollers 23 a and 23 b is large and greatly exceeds the wear limit B as the operation time elapses.

  On the other hand, according to the first and second embodiments, the outer peripheral wear amount of the first and second eccentric rollers 23a and 23b is lower than the wear limit B, and the wear amount is small.

  That is, according to the first and second embodiments, even when the compression mechanism unit 11 is operated at an operation frequency (for example, 90 Hz to 120 Hz) higher than the commercial power supply frequency, the first and second eccentric rollers 23a, The amount of outer peripheral wear of 23b can be suppressed below the wear limit B, and the reliability as a refrigeration cycle apparatus can be improved.

  Further, according to the second embodiment, the first and second blades 25a and 25b are composed of the same composition as that of the comparative example, while the hardness of the monichro cast iron of the first and second eccentric rollers 23a and 23b. By making HRC50 to HRC53 or higher, the outer circumferences of the first and second eccentric rollers 23a and 23b can be obtained without subjecting the first and second blades 25a and 25b to expensive surface treatment such as DLC coating. The amount of wear of the part can be reduced, and the wear limit B or less can be achieved.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of this invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the present invention. These embodiments and modifications thereof are included in the scope and gist of the present invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Refrigeration cycle apparatus, 2 ... Sealed compressor, 3 ... Condenser, 4 ... Expansion apparatus, 5 ... Evaporator, 7 ... Refrigerant piping, 8 ... Refrigeration cycle, 9 ... Sealed case, 10 ... Electric motor part, 11 ... Compression mechanism, 13 ... rotor (rotor), 18 ... first cylinder, 18a ... first cylinder chamber, 19 ... second cylinder, 19a ... second cylinder chamber, 23a, 23b ... first, first Two eccentric rollers, 25a, 25b... First and second blades.

Claims (5)

In a refrigeration cycle apparatus including a refrigeration cycle in which a hermetic compressor, a condenser, an expansion device, and an evaporator are connected by a refrigerant pipe, and R410A refrigerant is enclosed,
A refrigeration cycle apparatus characterized in that the condenser is formed by a parallel flow heat exchanger and the amount of the R410A refrigerant enclosed is in the range of 80 g to 130 g per kW of refrigeration capacity. The refrigeration cycle apparatus according to claim 1, wherein the operating frequency of the hermetic compressor when exhibiting the rated capacity is made higher than the commercial power supply frequency. The refrigeration cycle apparatus according to claim 1 or 2, wherein the hermetic compressor uses a rare earth magnet as a permanent magnet of an electric motor rotor. The hermetic compressor is a rotary compressor having a roller that rotates in a cylinder chamber, and a blade that slidably contacts the outer peripheral surface of the roller and partitions the cylinder chamber into a refrigerant suction chamber and a compression chamber. There,
The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the blade is made of a material having a substrate hardness of HRC60 or higher and subjected to DLC coding. The hermetic compressor is a rotary compressor having a roller that rotates in a cylinder chamber, and a blade that slidably contacts the outer peripheral surface of the roller and partitions the cylinder chamber into a refrigerant suction chamber and a compression chamber. There,
5. The refrigeration cycle apparatus according to claim 4, wherein the roller is made of Ni-Cr-Mo flake graphite alloy cast iron having a hardness of HRC53 or higher.

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