JPWO2013151043A1 - Refrigeration cycle equipment - Google Patents

Abstract

Conventionally, R32 refrigerant is known as a refrigerant of a refrigeration cycle apparatus. R32 refrigerant has low ozone toxicity and an ozone depletion potential (ODP) of 0 (zero). Moreover, although it is excellent in heat conveyance capability and cycle efficiency is also high, a global warming potential (GWP) is about 650. The problem to be solved by the present invention is effective in preventing global warming, and in order to obtain a safe and low-cost refrigeration cycle apparatus, a hermetic compressor, condenser, expansion device and evaporator are connected by refrigerant piping. It is connected and has a refrigeration cycle filled with R32 refrigerant. In addition, the condenser was formed by a parallel flow heat exchanger, and the amount of R32 refrigerant sealed was in the range of 70 g to 115 g per kW of refrigeration capacity.

Description

  Embodiments described herein relate generally to a refrigeration cycle apparatus.

Conventionally, R32 refrigerant is known as a refrigerant of a refrigeration cycle apparatus. R32 refrigerant has low ozone toxicity and an ozone depletion potential (ODP) of 0 (zero). Moreover, although it is excellent in heat conveyance capability and cycle efficiency is also high, a global warming potential (GWP) is about 650.
In addition, HFO-1234yf is a refrigerant with ODP of 0, low toxicity, and extremely low GWP.
There is a refrigerant (GWP = 4). However, when using HFO-1234yf refrigerant,
Since the heat transfer capability is low and the cycle efficiency is low, there is a problem that the cost further increases in order to increase the cycle efficiency.

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 R32 refrigerant is sealed is provided.
In addition, the condenser was formed by a parallel flow heat exchanger, and the amount of R32 refrigerant sealed was in the range of 70 g to 115 g per kW of refrigeration capacity.

The figure which shows the relative relationship of the charging amount of the R32 refrigerant | coolant per 1kW of refrigerating capacity which concerns on this embodiment, and the LCCP ratio (R32 / HFO-1234yf) of the R32 refrigerant | coolant with respect to a HFO-1234yf refrigerant | coolant. 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
Is composed of a twin-rotary hermetic compressor 2, a condenser 3 formed by a parallel flow heat exchanger, an expansion device 4, an evaporator 5 and an accumulator 6 sequentially connected by a refrigerant pipe 7,
A refrigeration cycle 8 is configured that encloses 32 refrigerants and circulates them in the direction of the arrows in the figure.
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. Further, the electric motor unit 10 is configured as a permanent magnet type electric motor provided with a permanent magnet formed of a rare earth magnet containing neodymium, samarium or the like on the rotor 13.
The stator 12 is electrically connected to the power supply terminal 14 of the hermetic compressor 2, and the 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 appropriately controls the operating frequency of the electric motor unit 10 to control the compression capacity by varying the rotational speed of the compression mechanism unit 11. The hermetic compressor 2 has a commercial power supply frequency (50 / 60H) when the refrigeration cycle apparatus 1 exhibits its rated capacity.
The size of the excluded volume is set so that the frequency is higher than z) (for example, 90 Hz).
The rotor 13 has a rotating shaft 16 inserted concentrically and fixed to the center thereof. The compression mechanism unit 11 is arranged in the lower part of the rotary shaft 16 in the vertical direction with the intermediate partition plate 17 interposed therebetween.
Cylinder 18 and a lower second cylinder 19 in the figure. A main bearing 20 is overlapped on the upper surface of the first cylinder 18, and the first cylinder 1 is connected via a first mounting bolt 21a.
8 is fixed. 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 rotating shaft 16 penetrates through the insides of the first and second cylinders 18 and 19 and is approximately 1
The first and second eccentric parts 16a and 16b are formed integrally with a phase difference of 80 °. 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. 1st, 2nd eccentric part 16a,
The outer peripheral surface of 16b is fitted with first and second eccentric rollers 23a and 23b having the same diameter.
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. Each cylinder chamber 1
8a and 19a are formed to have the same diameter and height, and the first and second eccentric rollers 23
Each of a and 23b is 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 HRC 53 to 55, and the height dimension thereof is set to each cylinder chamber 18.
It is formed substantially the same as the height dimension of a and 19a. Therefore, each cylinder chamber 18a, 19a
Are set to the same excluded volume. Each cylinder 18, 19 has a cylinder chamber 18a, 19a.
Blade chambers 24a and 24b communicated with each other. 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. ,
Line 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 accumulator 6.
Connected to the upper end of the. The accumulator 6 is connected to the compressor 1 with the first and second suction pipes 27a,
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, ..., and are brazed to the 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.
The refrigeration cycle 8 is filled with R32 refrigerant in the range of 70 g to 115 g per kW of refrigeration capacity of the refrigeration cycle 8 as the refrigerant.

Next, the operation of the refrigeration cycle apparatus 1 configured as described above will be described.
A control unit (not shown) gives a control signal for causing the inverter 15 to operate the compressor 2.
The inverter 15 operates the 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 23 are driven.
a 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 first cylinder chamber 18a is 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 retracted most.
Space capacity is maximized. For this purpose, the refrigerant gas flows from the accumulator 6 to the first suction pipe 2.
The first cylinder chamber 18a is sucked and filled through 7a. Here, the first eccentric roller 2
With the eccentric rotation of 3a, 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. 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, the second cylinder 19 side also has a second effect by substantially the same action as the first cylinder 18.
The high-pressure refrigerant gas compressed in the cylinder chamber 19a is discharged into the sealed case 9 from the second discharge port and filled.

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 again the first and second suction pipes 27a.
, 27 b is sucked into the compression mechanism 11 and the above-described operation is repeated, and the refrigerant circulates in the refrigeration cycle 8.
FIG. 1 shows an LCCP (Life) of a refrigeration cycle apparatus using HFO-1234yf refrigerant.
The relative relationship between the LCCP ratio, which is the ratio of the cycle temperature (product cycle climate load) and the LCCP of the refrigeration cycle apparatus using the R32 refrigerant, and the charging amount of the R32 refrigerant is shown by the curve A, and the LCCP ratio is 1 When smaller, the LCCP of the refrigeration cycle apparatus using the R32 refrigerant is smaller than the LCCP of the refrigeration cycle apparatus using the HFO-1234yf refrigerant, which indicates that it is effective for preventing global warming.

LCCP is an index when global warming prevention is considered, and TEWI (Total Eq
It is the numerical value which added the energy consumption (indirect influence) at the time of use greenhouse gas manufacture and the leakage (direct influence) to the open air to unity warming impact (total equivalent warming influence), and a unit is kg-CO2. 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 = GWPRM × W + GWP × W × (1−R) + N × Q × A

Here, GWPRM: 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: CO2 emission intensity, A: Annual power consumption In this embodiment, (1-R) = 0.7, N = 12 [years], Q = 0.378 [kgC
O2 / kWh].
In this refrigeration cycle apparatus 1, a parallel flow type heat exchanger is used as the condenser 3, an R32 refrigerant is used as the refrigerant, and the filling amount (enclosed amount) is 7 per kW of refrigeration capacity.
Since it is within the range of 0 g or more and 115 g or less, as shown in FIG. 1, HFO-1234y
f LCCP ratio (R32 / HFO-1) to LCCP of the refrigeration cycle apparatus using refrigerant
234yf) can be smaller than 1. That is, the refrigeration cycle apparatus 1 of the present embodiment using the R32 refrigerant is L less than the refrigeration cycle apparatus using the HFO-1234yf refrigerant.
It can be seen that CCP can be reduced and is effective in preventing global warming.

Note that the LCCP of the refrigeration cycle apparatus using HFO-1234yf uses the result of trial calculation using the highest system efficiency conceivable at the present time.
The present inventor conducted research and development to improve LCCP by using HFO-1234yf (GWP = 4), which has ODP = 0, low toxicity, extremely low GWP, and may be an alternative to R32 refrigerant.

However, when HFO-1234yf, which has a lower heat transfer capability than R32 refrigerant, is used as the refrigerant, the cycle efficiency is low. Therefore, in order to increase the cycle efficiency, it is necessary to increase the pipe diameter to increase the flow rate. The cost was raised.
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 was found that even when an R32 refrigerant having a slightly higher GWP is used, LCCP can be suppressed lower than when an HFO-1234yf refrigerant having a low cycle efficiency is used.

In addition, the LCCP of the refrigeration cycle apparatus using the R32 refrigerant has too little filling amount,
LCCP increases due to deterioration in cycle efficiency due to a lack of refrigerant, and if the amount is too large, the influence of GWP increases and LCCP increases. In contrast, the above 70g
HFO-1234 even if R32 refrigerant is used by keeping it in the range of ~ 115 g / kW.
LCCP can be kept lower than when yf refrigerant is used, and a refrigeration cycle apparatus that is effective in preventing global warming and 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 11 is a rotary type, if the operating frequency of the hermetic compressor when the refrigeration cycle apparatus 1 exhibits the rated capacity is increased, the sliding contact surfaces of the eccentric rollers 23a and 23b and the blades 25a and 25b. Slidability deteriorates, especially in the eccentric rollers 23a and 23b.
Wear is likely to proceed at the outer periphery of the.

FIG. 5 shows the relative relationship between the 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 power supply frequency. About this, it compares and shows this embodiment and 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 present embodiment, the first and second blades 25a and 25b are formed by subjecting a high-speed tool steel having a base material hardness of HRC 60 or higher to DLC coating, while the first and second blades 25a and 25b are formed.
This shows a case where the eccentric rollers 23a and 23b are made of monichro cast iron having a hardness HRC50.
In another 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. The case where it forms with monikuro cast iron is shown.

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.
And in the said comparative example, as shown in FIG. 5, the outer peripheral part wear amount of the 1st, 2nd eccentric roller 23a, 23b is large, and exceeds the wear limit B with progress of operation time, The wear limit B cannot be satisfied.

On the other hand, according to the above-described embodiment, 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 above-described embodiment, an operation frequency higher than the power supply frequency (for example, 90 Hz)
Even when the compression mechanism section 11 is operated at a frequency of up to 120 Hz), the first and second eccentric rollers 23
The outer peripheral wear amount of a and 23b can be suppressed to less than the wear limit B, and the reliability of the refrigeration cycle apparatus can be improved.

Further, according to another 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 is set. By making HRC50 to HRC53 or more, the first and second blades 25a and 25b can be made in the first and second without subjecting the surface treatment to expensive surface treatment such as DLC coating.
It is possible to reduce the amount of wear on the outer peripheral portions of the eccentric rollers 23a and 23b, and to satisfy the wear limit B.
As mentioned above, although 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,
DESCRIPTION OF SYMBOLS 7 ... Refrigerant piping, 8 ... Refrigerating cycle, 9 ... Sealing case, 10 ... Electric motor part, 11 ... Compression mechanism part, 13 ... Rotor (rotor), 18 ... 1st cylinder, 18a ... 1st cylinder chamber, 19 ...
Second cylinder, 19a, second cylinder chamber, 23a, 23b, first and second 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 R32 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 R32 refrigerant enclosed is in the range of 70 g to 115 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 HRC 60 or more 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 1, 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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