KR100653815B1 - Rotary compressor and air conditioner using the same - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide an air conditioner using a rotary compressor having a high coefficient of performance (COP) in all operating ranges by preventing a decrease in performance due to fluctuations in the intermediate pressure and suction in a high pressure compression element in a rotary compressor. There is.

A rotational compression element which serves as a low pressure compression element and a high pressure compression element, and an intermediate space connected to the low pressure compression element and the high pressure compression element, and comprising a phase difference between the low pressure compression element and the high pressure compression element. Refrigeration cycle having a rotary compressor having a temperature of 180 °, and a control unit for controlling the rotation of the compressor, wherein the ratio of the volume (Vm) of the intermediate space and the stroke volume (V1) of the compression element for the low pressure is the minimum rotation using the compressor. The number coefficient (Nmin) and the maximum rotational speed (Nmax) using the compressor were in a specific range, and the COP was improved in all operating ranges of the air conditioner equipped with the rotary two-stage compressor.

Rotary two stage compressor, rotary shaft, eccentric, cylinder, electric motor, compression element, compression chamber

Description

Air conditioner and rotary compressor used for it {ROTARY COMPRESSOR AND AIR CONDITIONER USING THE SAME}

1 is a longitudinal sectional view of a rotary two-stage compressor in one embodiment of the present invention;

2 is a configuration diagram of an air conditioner using a rotary two-stage compressor in one embodiment of the present invention.

3 is a diagram for explaining pressure fluctuations in each compression chamber and an intermediate space in a two-stage compressor.

4 is a diagram showing a relationship between the rotation speed N and the grade factor COP;

Fig. 5 is a diagram showing the relationship between (V1 / Vm) and the rotation speed Ns of the compressor according to the embodiment of the present invention.

Fig. 6 is a diagram showing the relationship between the rotation speed N and the performance coefficient COP of a compressor according to one embodiment of the present invention.

7 is a block diagram showing a control circuit of an air conditioner according to an embodiment of the present invention.

Fig. 8 is a diagram showing the relationship between the rotation speed N and the performance coefficient COP of an air conditioner according to an embodiment of the present invention.

9 is a configuration diagram of an air conditioner according to another embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

1: compressor

2: axis of rotation

5a, 5b: eccentric part

10: cylinder

11a, 11b: roller

14 electric motor

20a, 20b: compression element

23: compression chamber

25: inlet

32: middle space

The present invention relates to an air conditioner with a refrigeration cycle.

Background Art Conventionally, for example, a structure disclosed in Japanese Patent Laid-Open No. 60-128990 (hereinafter referred to as Patent Document 1) is known as a rotary two-stage compressor used in a refrigeration cycle. The compressor in this prior art is equipped with the electric motor which consists of a stator and a rotor in the upper part in a sealed container. The rotating shaft connected to the motor has two eccentric parts. As a compression mechanism corresponding to these eccentric portions, a high pressure compression element and a low pressure compression element are provided inside the sealed container in order from the electric motor side.

Each compression element orbits the roller by eccentric rotation of the eccentric portion of the rotary shaft. The eccentrics are 180 degrees out of phase, and the phase difference of the compression process of each compression element is 180 degrees. The compression process of the two compression elements is antiphase.

The gas refrigerant, which is the working fluid, is sucked into the low pressure compression element at low pressure Ps and is compressed to rise to the medium pressure Pm. The gas refrigerant discharged at the intermediate pressure Pm is discharged to the intermediate passage. The gas refrigerant of medium pressure Pm is then sucked into the high pressure compression element via the intermediate flow path and compressed to high pressure Pd.

The gas refrigerant of high pressure Pd discharged from the compressor is condensed into a condenser, and then reduced to a low pressure in the expansion mechanism. It is then evaporated in an evaporator to become a gas refrigerant and drawn into the low pressure compression element.

[Patent Document 1]

Japanese Patent Laid-Open No. 60-128990 (No. 5 page, Fig. 1)

In the rotary two-stage compressor as described in the prior art, the pressure ratio (= discharge pressure / suction pressure) of the individual compression elements is smaller than that of the single stage compressor, so that the leakage loss of the refrigerant and the like are reduced. This reduces the input power of the compressor and improves the coefficient of performance (COP) of the air conditioner. Here, the coefficient of performance (COP) is a value obtained by dividing the cooling or heating capacity of the air conditioner by the input power.                         

However, in the conventional rotary two-stage compressor, the pressure between the high pressure compression element and the low pressure compression element, that is, the pressure of the refrigerant gas discharged from the low pressure compression element and sucked into the high pressure compression element is varied. The pressure P1 of the compression chamber of the low pressure compression element is compressed from the low pressure Ps to the intermediate pressure Pm with the change of the angle of the eccentric direction (hereinafter referred to as crank angle) from the vane. The pressure of the space connecting the low pressure compression element and the high pressure compression element (hereinafter referred to as the intermediate space pressure P3) is 180 ° because the phase difference of the eccentric rotation of the two compression elements is lowered. In the case of being closed (the compression process of the low pressure compression element), the gas refrigerant is insufficient by the suction of the high pressure compression element and lowers than the intermediate pressure Pm. On the contrary, when the discharge valve of the low pressure compression element is open, the gas refrigerant becomes excessive by the discharge of the low pressure compression element, and the intermediate space pressure P3 rises above the intermediate pressure Pm. Therefore, the intermediate space pressure P3 of the refrigerant gas immediately after being discharged from the low pressure compression element fluctuates with respect to the crank angle.

Also, since the intermediate pressure Pm immediately after being discharged from the low pressure compression element passes through the intermediate space, the phase is delayed by Δτ just before the suction of the high pressure compression element. For example, even if the phase difference of each compression element is set to 180 °, the intermediate space pressure (P3) just before suction in the high pressure compression element is determined by the rotational speed of the compressor which drives two compression elements with one rotation shaft and compresses them in two stages. ) Coincides with the rising timing of the suction chamber and the suction start timing of the compression chamber. In this case, since the compression start pressure of the high-pressure compression element is high, the input of the compressor increases rapidly, resulting in a decrease in the compression efficiency, and furthermore, a decrease in the coefficient of performance (COP) of the air conditioner using the rotary two-stage compressor. It was causing.

An object of the present invention is to solve the above-described problems and to realize an air conditioner capable of obtaining a high coefficient of performance (COP) in its operating range. Further, another object of the present invention is to realize a rotary two-stage compressor capable of preventing the performance deterioration in the high pressure compression element.

Moreover, in order to achieve the objective of this invention, the air conditioner of this invention compresses an electric motor in a sealed container, the rotating shaft driven by the electric motor, and having two eccentric parts, and the roller which revolves by the eccentric rotation of the said eccentric part, respectively. The low pressure compression element and the high pressure compression element provided in the rotary compression element provided via a partition plate, and the inner space of the sealed container connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element A rotary compressor having an intermediate space, wherein a phase difference between the low pressure compression element and the high pressure compression element is approximately 180 °, a condenser for condensing the high pressure gas refrigerant discharged from the rotary compressor, and a condensed refrigerant A refrigeration cycle for sequentially connecting an expansion mechanism for expanding the pressure to a low pressure, an evaporator for evaporating the expanded refrigerant, and the compressor; A control unit for controlling the number of revolutions and the compressor by the controller is the operational control before and after the predetermined rotational speed region.

Moreover, in order to achieve the said objective, the air conditioner of this invention is equipped with the electric motor in the airtight container, the rotating shaft which is driven by the electric motor, and has two eccentric parts, and the roller which revolves by the eccentric rotation of the said eccentric part, respectively is provided in the compression chamber A rotary compression element provided with a low pressure compression element and a high pressure compression element via a partition plate, an inner space of the closed container and an intermediate space partitioned between the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element; And a rotary two stage compressor having a phase difference of about 180 ° between the low pressure compression element and the high pressure compression element, a condenser for condensing the high pressure gas refrigerant discharged from the compressor, and a condensed refrigerant. A refrigeration cycle for sequentially connecting an expansion mechanism for expanding to low pressure, an evaporator for evaporating the expanded refrigerant, and rotation of the compressor And a storage unit for storing the minimum and maximum rotational speeds of the operating speeds of the compressors, and the performance of the air conditioners from the minimum and maximum rotational speeds of the compressors. It operates at the rotation speed which avoided the rotation speed Ns of the said compressor which made the coefficient COP minimum.

Further, the ratio V1 / Vm of the stroke volume V1 of the low pressure compression element and the volume Vm of the intermediate space in the rotary compressor is the minimum operating rotation speed Nmin of the rotary compressor [1 / sec. ] And maximum operating rotation speed Nmax [1 / sec], it is preferable that (V1 / Vm)? 1.4 x 10 ^-5 Nmin ² and 2.6 x 10 ^-5 Nmax ² ? (V1 / Vm).

In addition, the air conditioner of the present invention, the expansion mechanism further comprises a first expansion mechanism for expanding by reducing the refrigerant condensed in the condenser to a medium pressure, and expands the refrigerant of the intermediate pressure expanded in the first expansion mechanism A gas-liquid separator connected to the first expansion mechanism and the second expansion mechanism to separate a gas refrigerant and a liquid refrigerant, and the gas-liquid separator and the intermediate space communicating mainly with the gas. An injection flow path for bypassing the coolant may be provided, and the flow path cross-sectional area of the injection flow path may be smaller than the minimum flow path cross-sectional area of the intermediate space.

In order to achieve another object of the present invention, the rotary two-stage compressor of the present invention comprises an electric motor in a sealed container, a rotating shaft driven by the electric motor and having two eccentric parts, and a roller eccentrically moved by the eccentric rotation of the eccentric part. The inside of the hermetic container connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element, wherein the low pressure compression element and the high pressure compression element provided in the compression chamber are coupled via a partition plate, respectively. In a rotary two-stage compressor having a space interspersed with a space, wherein the phase difference between the low pressure compression element and the high pressure compression element is approximately 180 °, the minimum operating rotation speed Nmin of the compressor. [1 / sec] and the maximum operating speed (Nmax) [1 / sec], the ratio (V1 / Vm) of the volume Vm of the intermediate space to the stroke volume V1 of the compression element for low pressure is (V1 / Vm) ≤ 1.4 × 10 ^-5 Nmin ² and 2.6 × 10 ⁻⁵ Nmax ² ≦ (V 1 / V m). The phase difference of the compression process of each compression element may be in the range of 150 ° to 210 ° with respect to 180 °.

Embodiments of the present invention will be described with reference to the drawings. First, in FIG. 1, the compressor 1 is provided with the airtight container 13 which consists of the bottom part 21, the cover part 12, and the fuselage | body part 22. As shown in FIG. Above the inside of the airtight container 13, the electric motor 14 which has the stator 7 and the rotor 8 is provided. The rotating shaft 2 connected to the electric motor 14 has two eccentric parts 5a and 5b and is journaled to the main bearing 9 and the sub bearing 19. The main bearing 9 which has the end plate part 9a in order from the electric motor 14 side with respect to the rotating shaft 2, the high pressure compression element 20b, the intermediate | middle partition board 15, and low pressure The sub-bearing 19 provided with the compression element 20a and the end plate part 19a is laminated | stacked, and is integrated with fastening elements (not shown), such as a bolt.

The end plate portion 9a is fixed to the inner wall of the body portion 22 by welding to support the main bearing 9. The end plate portion 19a is supported by the sub bearing 19. In addition, in this embodiment, although the end plate part 19a is fixed with a bolt etc., you may fix it to the trunk | drum 22 by welding.

Each compression element 20a and 20b is comprised as follows. The compression element 20a for low pressure is compressed by the sub-bearing 19, the cylindrical cylinder 10a, the cylindrical roller 11a fitted to the outer periphery of the eccentric part 5a, and the intermediate partition plate 15. The yarn 23a is configured. Further, the high pressure compression element 20b includes a main bearing 9, a cylindrical cylinder 10b, a cylindrical roller 11b fitted to the outer circumference of the eccentric portion 5b, and an intermediate partition plate 15. The compression chamber 23b is comprised. These compression chambers 23a and 23b are formed on the outer circumferential image of the rollers 11a and 11b in which a flat vane 18 connected to a pressing force applying means such as a coil spring rotates in accordance with the eccentric movement of the eccentric portions 5a and 5b. By advancing and retreating while contacting, the compression chambers 23a and 23b are divided into a compression space and a suction space.

The compression elements 20a, 20b drive the rollers 11a, 11b by the eccentric portions 5a, 5b rotating eccentrically. As shown in Fig. 1, the eccentric portion 5a and the eccentric portion 5b are 180 degrees out of phase, and the phase difference of the compression process of the compression elements 20a and 20b is 180 degrees. In other words, the compression process of the two compression elements is out of phase.

The flow of the gas refrigerant which is the working fluid is shown by the arrow of FIG. The gas refrigerant of low pressure Ps supplied through the pipe 31 is sucked into the low pressure compression element 20a from the suction port 25a connected to the pipe 31, and the roller 11a is eccentrically rotated so that the medium pressure ( Compressed to Pm). When the discharge valve 28a opened when the pressure in the compression chamber 23a reaches a preset pressure is opened at the intermediate pressure Pm, the discharge space in which the gas refrigerant at the intermediate pressure Pm communicates with the discharge port 26a ( 33). The discharge space 33 is a space separated from the sealed space 29 in the sealed container 13 by the sub-bearing 19 and the cover 35, and the internal pressure thereof is basically a medium pressure Pm. . The intermediate flow path 30 is a flow path communicating the discharge space 33 and the suction port 25b. One communicating space consisting of the discharge space 33, the intermediate flow path 30, and the suction port 25b is partitioned from the sealed container 13 to form an intermediate space 32 having an internal pressure Pm (in FIG. 1). Surrounded by a dotted line). Therefore, the gas refrigerant of the pressure Pm discharged from the discharge port 26a in which the discharge valve 28a is opened is discharged into the discharge space 33, and then, through the intermediate passage 30, the gas refrigerant of the high pressure compression element 20b is discharged. The inlet port 25b communicates with the pressure chamber 23b.

Next, the gas refrigerant of medium pressure Pm sucked into the high pressure compression element 20b from the suction port 25b through the intermediate flow path 30 is compressed to the high pressure Pd by the revolving roller 11b. When the discharge valve 28b opened when the pressure in the compression chamber 23b reaches a preset pressure is opened at a high pressure Pd, the gas refrigerant is sealed in the discharge port 26b, which is an internal space of the sealed container 13, 29 To be discharged. The gas refrigerant discharged into the sealed space 29 passes through the gap of the electric motor 14 and is discharged from the discharge pipe 27.

The configuration of the refrigeration cycle using the rotary two stage compressor described in FIG. 1 is shown in FIG. The gas refrigerant of the high pressure Pd discharged from the compressor 1 is condensed in the condenser 3 and then decompressed to the low pressure Ps in the expansion mechanism 4. Thereafter, the evaporator 16 evaporates to become a gas refrigerant and is sucked into the low pressure compression element 20a from the suction port 25a. The process by which the gas refrigerant in the compressor 1 moves each compression chamber 23 is as described with reference to FIG. Next, the relationship between each compression chamber 23a, 23b is demonstrated using FIG.

In the rotary compressor, the volume of the compression chamber 23 changes as the crank angle of the eccentric portion 5a changes based on the position of the vanes 18 to compress the refrigerant. In Fig. 2, the low pressure compression element 20a is located at a crank angle of 180 degrees. Partitioned by vanes 18, there are two spaces in the compression chamber 23a, that is, a compression space and a suction space. On the other hand, the crank angle of the high pressure compression element 20b is 0 degrees (360 degrees), and the low pressure compression elements 20a are 180 degrees out of phase. The state of the high pressure compression element 20b is a state in which the volume of the compression space is approximately minimum among two spaces existing in the low pressure compression element 20a, and the volume of the suction space is approximately maximum. In other words, the high pressure compression element 20b is in a state immediately before it is disconnected from the suction port 25b which is a part of the intermediate space 32 and communicates with the next suction space.

Next, the continuous pressure change in each compression element 20a, 20b of the rotary two-stage compressor 1 will be described. In Fig. 3, the pressure P1 at the lower end and the intermediate space pressure P3 represent the change of the pressure of the low pressure compression element 20a and the change of the pressure of the intermediate space 32, respectively. The pressure P3 ′ at the intermediate stage in FIG. 3 shows the change in pressure at the center of the intermediate space 32. The pressure P3 &quot; and the pressure P2 each represent a pressure change at the suction port 25b of the intermediate space 32 and a pressure change in the compression chamber 23b of the high pressure compression element 20b.

As shown in the lower part of Fig. 3, the pressure P1 of the compression chamber 23a of the low pressure compression element 20a changes from the low pressure Ps to the intermediate pressure Pm with the change of the crank angle. When the intermediate space pressure P3 compressed by the low pressure compression element 20a has a phase difference of 180 ° between the compression elements 20a and 20b, the discharge valve 28a of the low pressure compression element 20a is closed. [Compression Step of Low Pressure Compression Element 20a] By the suction of high pressure compression element 20b, the gas refrigerant is deficient and lowered (refer to FIG. 3, lower pressure P3). On the contrary, when the discharge valve 28a is open (the discharge process of the low pressure compression element 20a), the intermediate space pressure P3 which has been lower than the intermediate pressure Pm rises to the intermediate pressure Pm, and then the low pressure. By the discharge of the compaction element 20a, the gas refrigerant becomes excessive, and the intermediate space pressure P3 rises above the intermediate pressure Pm. Therefore, the intermediate pressure Pm immediately after the discharge of the compression chamber 23a fluctuates in a waveform with respect to the crank angle. 3, the broken line in FIG. 3 is an intermediate pressure Pm, and is an average value of the intermediate space pressure P3.

In addition, since the intermediate pressure Pm immediately after the discharge of the compression chamber 23a passes through the intermediate space 32, the phase is delayed by Δτ just before the suction of the compression chamber 23b. Therefore, even if the phase difference of each compression element 20a, 20b is set to 180 degrees, according to the operating speed of the compressor 1, the high pressure compression element 20b raises and compresses the intermediate space pressure P3 just before suction. Matching with the suction start of the seal 23b may occur. In this case, since the compression start pressure P3 of the compression chamber 23b is high, the input of a compressor increases rapidly and it causes the fall of compression efficiency. In addition, when the compressor is operated at the rotational speed resulting in such a state, a decrease in the coefficient of performance (COP) of the refrigerating device using the compressor is also caused.

The phase interference between the rising interval of the intermediate space pressure P3 and the suction interval of the gas refrigerant in the high pressure compression element 20b is determined by the circulation flow rate of the refrigerant and the volume Vm of the intermediate space 32 (hereinafter, intermediate). Volume) and the rotation speed N of the compressor. Since the circulating flow rate of the refrigerant is approximately proportional to the stroke volume V1 and the rotational speed N of the low pressure compression element 20a, the performance deterioration due to interference is reduced to the intermediate volume Vm and the stroke volume of the low pressure compression element V1. ) And the rotational speed N become the characteristics of FIG.

4, the horizontal axis represents the rotational speed N, and the vertical axis represents the performance coefficient COP of the air conditioner. The coefficient of performance (COP) of the air conditioner using the rotary two-stage compressor 1 is represented by C2. In Fig. 4, the coefficient of performance (COP) of the single stage compressor is also written as C1.

The coefficient of performance COP of a single stage compressor has the maximum value with increase of the rotation speed N, and then falls gently. In the two stage compressor 1, the dependence of the coefficient of performance COP on the rotational speed N is about the same with respect to the maximum value. As a whole, the coefficient of performance COP of the two stage compressor 1 increases. However, for the ratio of the stroke volume and the intermediate volume (V1 / Vm) of a particular low pressure compression element, the performance factor for a specific number of rotations (Ns) that amplifies the phase interference in the high pressure compression element 20b described above. It shows the characteristic that (COP) becomes the minimum value. The decrease in this performance is about 3 to 8%, which greatly reduces the performance of the air conditioner. The range of performance degradation ranges from 0.85 Ns to 1.15 Ns centering on the specific rotation speed Ns based on the comparison with the coefficient of performance COP of the single stage compressor.

As shown by the broken line in Fig. 4, when the specific volume ratio V1 / Vm is changed, the specific rotation speed Ns changes. This is because the phase retardation Δτ changes when the specific volume ratio V1 / Vm changes, and therefore, the interference state between the fluctuation of the intermediate space pressure P3 and the suction start interval of the compression chamber 23b changes. Here, as shown in Fig. 4, the specific rotational speed Ns is a specific volume ratio V1 / Vm as the dominant variable, and the influence of the pressure condition can be ignored.

Therefore, the air conditioner to which the present invention is applied operates in the rotational speed range including the rotational speed at least before and after the specific rotational speed Ns, which is lower than the performance coefficient COP of the single stage compressor. Do not do it. Specifically, the rotational speed of the two-stage compressor is increased, and the predetermined rotational speed region is increased to the rotational speed beyond the rotational speed region substantially over a short time beyond the maximum value of the coefficient of performance (COP). Similarly, when driving at a speed lower than the speed range from the state of operating at a speed exceeding the speed range, the rotation speed is changed so that the operation in the speed range passes in a short time compared to other places. By performing the rotation speed control of the two-stage compressor in this way, the operation time in the rotation speed range where the coefficient of performance (COP) is reduced can be reduced to the maximum, and the performance of the air conditioner can be improved.

Next, one Embodiment of this invention is described more concretely using drawing. It is good also as a compressor used for an air conditioner using the refrigerant | coolant R410A as a working fluid for the rotary two-stage compressor 1, for example. In this case, the rotation speed N of the compressor 1 is controlled by an inverter, and the ratio of the maximum rotation speed Nmax and the minimum rotation speed Nmin that operates is 1.4 or more.

The basic configuration of the rotary two stage compressor 1 of this embodiment is shown in FIG. The stroke volume of the intermediate volume Vm and the low-pressure compression element 20a with respect to the minimum rotation speed Nmin [1 / sec] and the maximum rotation speed Nmax [1 / sec] for operating this compressor 1 ( The compressor 1 is mounted in the air conditioner by setting the specific volume ratio V1 / Vm of V1) to (V1 / Vm) ≤ 1.4 × 10 ^-5 Nmin ² , 2.6 × 10 ^-5 Nmax ² ≤ (V1 / Vm). In this case, the COP can be improved at all driving speeds. In the case of the refrigerant R410A, the condition of the ratio of rotation speed (Nmax / Nmin)> 1.4 is required, but this condition is a general condition in the air conditioner in which the inverter controls the rotation speed of the compressor. In the compressor 1 of the present embodiment it was to specifically (Nmax / Nmin) = 6, (V1 / Vm) = 2.6 × 10 -5 Nmax 2.

The relationship between the specific volume ratio V1 / Vm and the minimum and maximum compressor revolutions will be described. First, as shown in Fig. 4, a correlation is established between the specific volume ratio V1 / Vm of the rotary two-stage compressor and the specific rotational speed Ns which minimizes the coefficient of performance COP. 5 shows the relationship between the specific volume ratio V1 / Vm and the specific rotational speed Ns. As shown in Fig. 5, the relationship between the two can be approximated by Ns = 230 (V1 / Vm) ^0.5 , and the specific rotation speed Ns changes depending on the specific volume ratio V1 / Vm. In addition, as shown in Fig. 4, since the performance deteriorates in the range of 0.85 Ns to 1.15 Ns, the upper limit of the specific volume ratio (V1 / Vm) of the compressor 1 does not deteriorate below Nmax so that Ns = 1.18 Nmax (Nmax). It was set as 2.6 * 10 <^-5> Nmax <^2> corresponded to = 0.85 Ns).

In contrast, the lower limit of the specific volume ratio V1 / Vm of the compressor 1 is 1.4 × 10 ⁻⁵ Nmin ² , which corresponds to Ns = 0.87 Nmin (Nmin = 1.15 Ns) so that the performance does not deteriorate at or above Nmin. If these relationships are represented by specific volume ratios (V1 / Vm), then (V1 / Vm) ≦ 1.4 × 10 ⁻⁵ Nmin ² , 2.6 × 10 ⁻⁵ Nmax ² ≦ (V1 / Vm).

6 shows the relationship between the rotation speed N of the compressor 1 in the present embodiment and the performance coefficient COP of the air conditioner in which the compressor 1 is mounted. Since the compressor 1 set the specific volume ratio V1 / Vm to 2.6 × 10 ^-5 Nmax ² , the rotational speed Ns that minimizes the coefficient of performance COP is 1.18 Nmax (Nmax = 0.85 Ns). The interference of the phase in the compression chamber 23b is suppressed up to the maximum rotation speed Nmax to be used, and the compressor 1 can be operated with high efficiency in all the operating ranges.

FIG. 6 is shown an embodiment of a towing application specific volume ratio (V1 / Vm) = 1.4 × 10 -4 characteristics of Nmin ² by broken lines. In this case, on the contrary, the rotation speed Ns which minimizes the coefficient of performance COP is 0.87 Nmin (Nmin = 1.15 Ns). As can be seen in this application, the compressor 1 can be operated with high efficiency in all operating ranges over the minimum rotational speed Nmin to be used.

Next, a description will be given using Figs. 7 and 8. The air conditioner according to the embodiment of the present invention has a low pressure that controls the rotation speed Ns of the compressor in consideration of the coefficient of performance COP of the air conditioner in terms of controlling the operation from the minimum rotation speed to the maximum rotation speed of the compressor. The rotary two-stage compressor (1) having a predetermined (V1 / Vm) in consideration of the relationship between the stroke volume (V1) of the pressure compression element and the volume (Vm) of the intermediate space between the low pressure compression element and the high pressure compression element. Is operated at the minimum rotation speed (Nmin) ≤ Ns ≤ the maximum rotation speed (Nmax) to improve the versatility of the design. That is, even if the maximum capability and minimum capability of an air conditioner differ, it aimed at using the same rotary two stage compressor 1 to improve the COP.

Although the structure of the air conditioner of this embodiment is the same as that of FIG. 1, it is characterized by the control of the compressor 1 and its rotation speed N. As shown in FIG.

The control circuit of the rotation speed N of the compressor 1 is shown in FIG. The user of the air conditioner inputs a set value of the room temperature, humidity or air volume from an indicator device (not shown) such as a remote controller or an input terminal. The signal reception unit 201 of the control circuit receives the input signal. The signal receiving unit 201 converts the received input signal and transmits it as a control signal for the decompression amount of the expansion mechanism or the blower's rotation speed and the control signal to the compressor 1.

The signal to the compressor 1 is specifically the command value T * of room temperature, and the difference (DELTA) T from the measured value from the temperature detector 202 installed in the indoor unit (not shown) is transmitted downstream. Thereafter, the rotation speed conversion unit 203 performs rotation speed conversion so as to be approximately proportional to ΔT, and the rotation speed signal ΔN is transmitted. The sum of ΔN and the measured value N from the rotation speed detector 204 becomes the rotation speed signal N *.

In the first judging unit 205, when the rotational speed signal N * is 0.85 Ns or more or 1.15 Ns or less from the minimum and maximum operating speeds of the compressor 1 stored in the storage unit (not shown). The second judging unit 206 judges about ΔN. Specifically, when ΔN is greater than or equal to O, that is, the rotational speed N, N * = 1.15 Ns or more, and is 1.17 Ns. When ΔN is less than or equal to O, that is, the rotational speed N, N * = 0.85 Ns The signal is converted to a smaller value of 0.83 Ns. In the first determination unit 205, when the rotational speed signal N * is smaller than 0.85 Ns or larger than 1.15 Ns, the rotational speed signal N * is not converted. In the air conditioner of this embodiment provided with this control circuit, the compressor 1 is operated by these rotation speed signals N *. Here, N * = 1.17Ns and N * = 0.83 Ns are values which were increased or decreased in consideration of the detection error of the temperature and the rotation speed or the control sensitivity of the rotation speed with respect to 1.15 Ns and 0.85 Ns, respectively.

In the air conditioner of this embodiment controlled as described above, as shown in Fig. 8, the operating range is smaller than 0.85 Ns (operation A) or larger than 1.15 Ns (operation B), and the minimum value (Ns) that degrades the performance. The compressor 1 is operated except for (0.85 Ns ≤ rotational speed N ≤ 1.15 Ns). Therefore, since the air conditioner in one Embodiment of this invention can use the rotary two-stage compressor 1 with high efficiency, it becomes possible to improve the high performance in the full operation range.

Next, another embodiment of the air conditioner to which the present invention is applied will be described. This air conditioner uses an injection cycle. As shown in Fig. 9, the refrigerant gas of the high pressure Pd discharged from the rotary two-stage compressor 1 which is one embodiment of the present invention is condensed by the condenser 3, and then the first expansion mechanism 4 The pressure is reduced to an intermediate pressure (Pm) by expanding at. This reduced pressure refrigerant gas is separated into gas and liquid in the gas-liquid separator 6. The separated liquid refrigerant is depressurized again to the low pressure Ps in the second expansion mechanism 4 downstream of the gas-liquid separator 6, and then evaporated in the evaporator 16 to become a gas refrigerant. The gas refrigerant of low pressure Ps is sucked into the low pressure compression element 20a from the suction port 25a, and the roller 11a fitted to the eccentric portion 5a revolves to be compressed to the intermediate pressure Pm, It is discharged to the space 32.

The gas refrigerant in the intermediate space 32 is mixed with the gas refrigerant of medium pressure Pm derived from the injection passage 17 in which the gas-liquid separator 6 and the intermediate passage 30 communicate. Thereafter, the gas refrigerant of medium pressure Pm sucked into the high pressure compression element 20b from the suction port 25b is compressed and discharged to the high pressure Pd by the revolving roller 11b fitted to the eccentric portion 5b. It is discharged from the tube 27.

This injection cycle reduces the extra circulating flow rate to the low pressure compression element 20a in order to bypass the gas refrigerant having low heat transfer performance in the evaporator 16, thereby reducing the compression work and improving the coefficient of performance of the air conditioner. Improve the COP. In addition, an anisotropic valve 34 for opening and closing the oil passage 17 is provided in the middle of the injection passage 17. When the anisotropic valve 34 is opened, an injection cycle is formed, and when the anisotropic valve 34 is closed, the example shown in FIG. It is good also as a switchable structure used as a normal refrigeration cycle.

In the air conditioner of this embodiment, the flow path cross-sectional area of the injection flow path 17 is made smaller than the minimum flow path cross-sectional area of the intermediate space 32. The minimum passage cross-sectional area of the intermediate space 32 is the passage cross-sectional area of the intermediate passage 32 and the suction port 25b (see Fig. 1). According to this embodiment, the inflow and outflow of the excess gas refrigerant from the injection flow path 17 to the intermediate space 32 can be restrict | limited. Moreover, the change of the intermediate space 32 by the internal volume of the injection flow path 17 can be suppressed to the maximum. Therefore, the injection can be performed without changing the phase delay Δτ of the intermediate pressure Pm shown in FIG. Therefore, the effect of the injection cycle can be obtained by utilizing the characteristics of the compressor 1.

According to the present invention, an air conditioner capable of realizing a high coefficient of performance (COP) in all operating ranges can be obtained by using a rotary two-stage compressor capable of preventing performance deterioration in a high pressure compression element.

Claims (9)

A low pressure compression element and a high pressure compression element each having a motor, a rotary shaft driven by the electric motor and having two eccentric portions, and a roller which revolves by eccentric rotation of the eccentric portion in the compression chamber, respectively, are provided with a partition plate. And an intermediate space partitioned from the inner space of the hermetic container connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element provided through the rotary compression element, and the low pressure compression element and the high pressure compression. A rotary compressor having a phase difference of about 180 ° in the compression process of the urea, a condenser for condensing the high-pressure gas refrigerant discharged from the rotary compressor, an expansion mechanism for expanding the condensed refrigerant to a low pressure, and an evaporator for evaporating the expanded refrigerant And a control unit for controlling the rotation speed of the compressor, And the control unit performs driving control at a rotational speed exceeding the predetermined rotational speed region or at a rotational speed lower than the predetermined rotational speed region without performing operation control in a predetermined rotational speed region. delete The ratio (V1 / Vm) of the stroke volume (V1) of the low pressure compression element and the volume (Vm) of the intermediate space in the rotary compressor is the minimum operating speed (Nmin) of the rotary compressor. (V1 / Vm) ≤ 1.4 × 10 ^-5 Nmin ² and 2.6 × 10 ^-5 Nmax ² ≤ (V1 / Vm) with [1 / sec] and maximum operating speed (Nmax) [1 / sec] Air conditioner. According to claim 1 or 3, wherein the expansion mechanism is a first expansion mechanism for expanding by reducing the refrigerant condensed in the condenser to a medium pressure, and expands the refrigerant of the intermediate pressure expanded in the first expansion mechanism to A gas-liquid separator comprising a second expansion mechanism supplied to the evaporator, the gas-liquid separator connected to the first expansion mechanism and the second expansion mechanism to separate a gas refrigerant and a liquid refrigerant, and a gas refrigerant region and the intermediate portion of the gas-liquid separator. An air conditioner having an injection passage communicating with a space, wherein the passage cross-sectional area of the injection passage is smaller than the minimum passage cross-sectional area of the intermediate space. A low pressure compression element and a high pressure compression element each having a motor, a rotary shaft driven by the electric motor and having two eccentric portions, and a roller which revolves by eccentric rotation of the eccentric portion in the compression chamber, respectively, are provided with a partition plate. And an intermediate space partitioned from the inner space of the hermetic container connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element provided through the rotary compression element, and the low pressure compression element and the high pressure compression. A rotary compressor having a phase difference of about 180 ° in the compression process of the urea, a condenser for condensing the high-pressure gas refrigerant discharged from the rotary compressor, an expansion mechanism for expanding the condensed refrigerant to a low pressure, and an evaporator for evaporating the expanded refrigerant And a control unit for controlling the rotational speed of the compressor, and the control unit The rotation speed of the said compressor which has the memory part which memorize | stores the minimum rotation speed and the maximum rotation speed of the operation | movement speed of a machine, and minimizes the performance coefficient (COP) of the said air conditioner from the minimum rotation speed and the maximum rotation speed of the said compressor. Air conditioner driving at rpm avoiding (Ns). The rotational speed Ns of the compressor which minimizes the COP of the air conditioner is set to the minimum and maximum rotational speeds of the operating speed of the compressor, and the rotary compressor. An air conditioner operating at a rotational speed avoiding the rotational speed (Ns) obtained from the relationship between the ratio of the volume (Vm) of the intermediate space to the stroke volume (V1) of the compression element for low pressure. The ratio V1 / Vm of the stroke volume V1 of the low pressure compression element and the volume Vm of the intermediate space in the rotary compressor is the minimum operating speed Nmin of the rotary compressor. (V1 / Vm) ≤ 1.4 × 10 ^-5 Nmin ² and 2.6 × 10 ^-5 Nmax2 ≤ (V1 / Vm) when [1 / sec] and the maximum operating speed (Nmax) [1 / sec] are set. Air conditioner. The said expansion mechanism is a 1st expansion mechanism which expands by decompressing the refrigerant | coolant condensed by the said condenser to intermediate pressure, and expands in the said 1st expansion mechanism. And a gas-liquid separator for expanding the medium pressure refrigerant to be supplied to the evaporator, the gas-liquid separator being connected to the first expansion mechanism and the second expansion mechanism to separate gas refrigerant and liquid refrigerant, and the gas-liquid separator. An air conditioner, comprising: an injection flow path communicating the gas refrigerant region in the gas passage with the intermediate space, wherein the flow path cross-sectional area of the injection flow path is smaller than the minimum flow path cross-sectional area of the intermediate space. A low pressure compression element and a high pressure compression element each having a motor, a rotary shaft driven by the electric motor and having two eccentric portions, and a roller which revolves by eccentric rotation of the eccentric portion in the compression chamber, respectively, are provided with a partition plate. And an intermediate space partitioned from the inner space of the sealed container connected to the compression chamber of the low pressure compression element and the compression chamber of the high pressure compression element provided through the rotary compression element. In a rotary two-stage compressor having a phase difference of approximately 180 degrees in the compression process of the compression element, the minimum operating speed Nmin [1 / sec] and the maximum operating speed Nmax [1 / sec] of the compressor, The ratio (V1 / Vm) of the stroke volume (V1) of the low pressure compression element to the volume (Vm) of the intermediate space is (V1 / Vm) ≤ 1.4 × 10 ^-5 Nmin ² and 2.6 × 10 ^-5 Nmax ² ≤ ( V1 / Vm), the rotary compressor.

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