JPS59176543A - Heat pump type room air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a heat pump room near conditioner using a compressor having two compression elements consisting of a main compression element and an auxiliary compression element. This invention relates to a heat pump type room near conditioner aimed at capacity control.

[Prior art]

A heat pump room near conditioner using a compressor with two compression elements will be explained with reference to FIGS. 1-2.

Figure 1 is a cycle configuration diagram showing an example of a conventional heat pump room near conditioner using a compressor with two compression elements, and Figure 2 is a sectional view showing details of the compressor in Figure 1. be.

In FIG. 1, 1 indicates a main compression element 2 and an auxiliary compression element 3.
This is a hermetic compressor (details will be described later) relating to a compressor having. Main compression element 2. The auxiliary compression element 3 is, for example, a unit compressor that constitutes the hermetic compressor 1, and only the main compression element 2 is used during capacity control.

The discharge pipe 4 of the main compression element 2 joins the discharge pipe 5 of the auxiliary compression element 3 at the inlet of the high-pressure gas pipe 6. This high pressure gas piping 6 is connected by switching the four-way switching valve 7.
During heating operation, an indoor heat exchanger 8 (acts as a condenser), a pressure reducer 9. The outdoor heat exchanger 10 (acts as an evaporator) and the four-way switching valve 7 are connected so that the refrigerant flows in this order, and during cooling operation, the outdoor heat exchanger 10 (acts as a condenser), the pressure reducer 9. The indoor heat exchanger 8 (acting as an evaporator) and the four-way switching valve 7 are connected in this order so that the refrigerant flows therethrough.

Until returning from the four-way switching valve 7 to the hermetic compressor 1,
Although they are connected by a low-pressure gas pipe 11, they are separated into a main compression element suction pipe 12 and an auxiliary compression element suction pipe 13 along the way, and each suction pipe 12.13 is connected to the main compression element 2.13. Connected to the auxiliary compression element 3, a two-way valve 14 for capacity control is provided in the middle of the auxiliary compression element suction pipe 13.

The hermetic compressor 1 will be explained in more detail using FIG. 2. Reference numeral 15 denotes a chamber, and the stator 16 of the motor is housed in the chamber 15. The main compression element cylinder 2'' block 17 is fixed and held, and this chamber 15 forms a high-pressure pressure chamber.

An upper bearing 18 is fixed to the upper part of the main compression element cylinder block 17, and the upper bearing 18 rotatably holds a crankshaft 20 into which a motor rotor 19 is fitted.

The lower end of the crankshaft 20 is held in rotation by a lower bearing 22 having an auxiliary compression element discharge chamber 21 therein, and this lower bearing 22 is connected to an auxiliary compression element cylinder block 23. It is fixed to the main compression element cylinder block 17 together with the partition plate 24 .

Upper bearing 18, main compression element cylinder block 17. A compression chamber 25 of the main compression element 2 is formed by the partition plate 24, while the partition plate 24. Auxiliary compression element cylinder block 23. Compression chamber 2 of auxiliary compression element 3 with lower bearing 22
6 is formed.

The compression stroke of the hermetic compressor 1 configured in this way is performed by the main compression elements 2, 2, and 2, respectively. Compression chamber 25.26 of auxiliary compression element 3
The roller 27 . of the main compression element 2 is rotated eccentrically by the crankshaft 20 within the roller 27 . This is done by means of an auxiliary compression element 30 roller 28. The flow of refrigerant gas in the main compression element 2 is sucked into the compression chamber 25 from the main compression element suction pipe 12, and after being compressed, is discharged from the main compression element discharge valve 29 into the chamber 15, which is a high-pressure pressure chamber. Thereafter, the rotor 19 and stator 16 of the motor are cooled, and the compressed air is discharged from the main compression element discharge pipe 4. On the other hand, the flow of refrigerant gas within the auxiliary compression element 3 is sucked into the compression chamber 26 from the auxiliary compression element suction pipe 13, and after compression is discharged from the auxiliary compression element discharge valve 30 into the auxiliary compression element discharge chamber 21. After that, the lower bearing 22. It passes through a discharge passage 31 provided in the auxiliary compression element cylinder block 23 and is discharged from the auxiliary compression element discharge pipe 5 .

In the heat pump type room near conditioner using this hermetic compressor 1, when the load of the refrigeration cycle becomes small, even if an attempt is made to control the capacity of the hermetic compressor 1, since the crankshaft 20 is an integral structure, The auxiliary compression element 3 cannot be separated from the main compression element 2.

Hereinafter, a capacity control method of a heat pump type roomier conditioner using this hermetic compressor 1 and its problems will be explained using FIGS. 1 to 4.

Figure 3 is a heating capacity diagram showing the relationship between the heating capacity and outside air temperature of the heat pump room near conditioner shown in Figure 1. It is an adiabatic compression efficiency diagram showing a comparison of compression efficiencies.

In FIG. 3, a dashed line 45 indicates the heating load, which increases in inverse proportion to the decrease in outside air temperature.

On the other hand, the heating capacity of the heat pump air conditioner decreases in proportion to the decrease in outside air temperature, as shown by solid lines 46 and 4.7 in the figure. The upper solid line 46 is the heating capacity when the compression element 2 and the auxiliary compression element 3 are operated in parallel, that is, without capacity control, and the lower solid line 47 is the heating capacity when the refrigerant flowing to the auxiliary compression element 3 is stopped by the three-way valve 14. In other words, it is the heating capacity when the capacity is controlled.

The heating capacity must match the heating load by approximately 9, but as is clear from Figure 3, the slopes of the heating capacity and heating load are opposite.

(1) When the outside air temperature is in range A In this case, the outside air temperature is low and heating load > heating capacity, and continuous operation is performed with the two-way valve 14 open (that is, without capacity control).

To explain the flow of the refrigerant in this case, the low pressure gas pipe 11
The low-pressure gas refrigerant that returns to the hermetic compressor 1 passes through the main compression element suction pipe 12 and the auxiliary compression element suction pipe 13, is sucked into the main compression element 2 and the auxiliary compression element 3, and is compressed. The compressed high-pressure gas refrigerant is discharged from the main compression element discharge pipe 4 and the auxiliary compression element discharge pipe 5,
The gases are joined together in a high-pressure gas pipe 6, and sent to an indoor heat exchanger 8 by a four-way switching valve 7, where they are heat-radiated and condensed. The high-pressure liquid refrigerant after condensation is depressurized by a pressure reducer 9 and sent to a low-pressure, low-temperature refrigerant. After absorbing heat and evaporating in an outdoor heat exchanger 10, the high-pressure liquid refrigerant is returned to a low-pressure gas pipe 11 by a four-way switching valve 7, which is a cycle. .

(2) When the outside air temperature is in range C In this case, the outside air temperature is high and the heating load (heating capacity) is reached, and intermittent operation is performed with the two-way valve 14 closed (that is, the capacity is controlled).

In this case, since the refrigerant does not flow to the auxiliary compression element 3,
The above-described cycle operation (1) is performed using only the main compression element 2.

(3) When the outside air temperature is in range B In this case, the heating load is between the heating capacity 46 and the heating capacity (9) 47, so by closing or opening the three-way control valve 14, Perform switching operation.

The problem with the conventional capacity control method described above is the above (3).
When the switching operation related to the above is performed, the heating capacity fluctuates greatly at the time of switching, so the temperature fluctuation in the air-conditioned room increases. In order to prevent this, fine-grained capacity control has been desired.

Further, in the conventional method described above, in which the capacity is controlled by stopping the flow of refrigerant to the auxiliary compression element 3 by closing the two-way valve 14 for capacity control, although the configuration of the refrigeration cycle is simple, the auxiliary compression element 3 is Due to the vacuum operation, there is a large leak between the partition plate 24 and the end face of the roller 28 of the auxiliary compression element 3, or between the lower bearing 22 and the end face of the roller 28, and the adiabatic compression efficiency of the hermetic compressor 1 is lower than the capacity. This is significantly lower than when no control is applied.

This will be explained using FIG. 4.

In FIG. 4, the horizontal axis represents the compression ratio of the compressor, and the vertical axis represents the adiabatic compression efficiency of the compressor, each scaled to (10). D is the adiabatic compression efficiency of the hermetic compressor 1 when the main compression element 2 and the auxiliary compression element 3 are operated in parallel, that is, when the capacity is not controlled, and E is the auxiliary with the two-way valve 14 for capacity control. The adiabatic compression efficiency of the hermetic compressor 1 is shown when the refrigerant flowing to the compression element 3 is stopped, that is, when the capacity is controlled (F will be described later).

As is clear from this figure, E is significantly lower than D.

By the way, when the capacity is controlled, the capacity of the hermetic compressor 1 decreases, and therefore the heat exchangers (that is, the indoor heat exchanger 8 and the outdoor heat exchanger 10) become relatively large, and the refrigeration The coefficient of performance of the cycle (refrigeration capacity/power consumption) should improve, but as mentioned above, the hermetic compressor 1
Since the reduction in adiabatic compression efficiency is large, power consumption increases and the coefficient of performance of the refrigeration cycle deteriorates.

[Purpose of the invention]

The present invention eliminates the drawbacks of the prior art described above and provides (11
) The object of the present invention is to provide a heat pump type room air conditioner that is capable of fine-grained capacity control and has an excellent coefficient of performance during capacity control.

[Summary of the invention]

The heat pump room air conditioner according to the present invention includes a compressor having a main compression element and an auxiliary compression element, a high-pressure gas pipe, a condenser, and a pressure reducer.

Refrigerant is circulated to the evaporator, low pressure gas piping, and the compressor,
In a heat pump room air conditioner that controls the capacity of the refrigeration cycle when the load is small, the pressure reducer is divided into a condenser-side pressure reducer and an evaporator-side pressure reducer, and a pressure reducer is installed between these pressure dividers. An intermediate mixer is installed,
An auxiliary compression element discharge pipe that makes the theoretical displacement of the auxiliary compression element 0.5 to 1.5 times the theoretical displacement of the main compression element and connects the discharge side of the auxiliary compression element to a high-pressure gas pipe. A first control valve that stops the flow of refrigerant during capacity control is provided in the middle of the main compression element suction pipe that connects the suction side of the main compression element and the low-pressure gas pipe. A second control valve is provided (12) to stop the inflow, and a two-way inflow prevention valve is provided on the auxiliary compression element side in the middle of the intermediate mixer inflow pipe that connects the auxiliary compression element side of the first control valve and the intermediate mixer. A condensed refrigerant backflow prevention check valve is provided on the intermediate mixer side, and an outflow prevention check valve is provided in the middle of a gas outflow pipe connecting the main compression element side of the second control valve and the intermediate mixer. a two-way valve on the gas outflow pipe, the side being closer to the main compression element than the two-way valve for preventing outflow on the gas outflow pipe;
By providing a bypass control valve in the middle of a bypass pipe that connects the two-way valve for preventing inflow of the intermediate mixer inflow pipe and the check valve for preventing backflow of condensed refrigerant, the above-mentioned An auxiliary compression element is connected in series with the main compression element, and during small capacity control, the auxiliary compression element is connected in series with the main compression element via the intermediate mixer.

In more detail, the capacity control of a heat pump room air conditioning conditioner using a hermetic compressor in which two compression elements, a main compression element and an auxiliary compression element are housed in a chamber, will be described in Section 13. ) Large-capacity control (i.e., low-capacity operation) that directs the discharged gas refrigerant of the auxiliary compression element to the suction side of the main compression element where it does work.
and ■ the discharged gas refrigerant of the auxiliary compression element that does not do any work;
The liquid refrigerant after condensation is mixed with a two-phase refrigerant whose pressure is reduced by a pressure switch between the condensation pressure and the evaporation pressure in an intermediate mixer, and only the gas refrigerant of the two-phase refrigerant after this mixing is made to do work. By using two-stage capacity control with medium capacity control (that is, medium capacity operation) that leads to the suction side of the main compression element, fine capacity control is possible, and the compression of the auxiliary compression element that does not perform any work is possible during both capacity controls. The chamber is also filled with refrigerant gas to reduce leakage of refrigerant oil and refrigerant in the chamber, which is a high-pressure chamber, into the compression chamber, thereby improving the coefficient of performance during capacity control. .

[Embodiments of the invention] The present invention will be explained below with reference to Examples.

FIG. 5 is a cycle configuration diagram of a heat pump type room air conditioner 7 according to an embodiment of the present invention, and FIG. 6 is a refrigeration cycle diagram during capacity control of the heat pump type room air conditioner (14) according to FIG. 5. FIG. 7 is a heating capacity diagram showing the relationship between the heating capacity of the heat pump type room air conditioner according to FIG. 5 and the outside air temperature.

In FIG. 5, parts given the same numbers as in FIG. 1 are the same parts. 43 is an indoor heat exchanger side pressure reducer related to the condenser side pressure reducer, and 44 is an outdoor heat exchanger side pressure reducer related to the evaporator side pressure reducer. The pressure reducer 9 in FIG. 1 is divided into two parts. An intermediate mixer 34 is disposed between these.

IA is set so that the theoretical displacement amount of the auxiliary compression element 3A/the theoretical displacement amount of the main compression element 2A (hereinafter, this ratio will be referred to as the theoretical displacement amount ratio) is 0.5 to 1.5. This is a hermetic compressor. The theoretical displacement ratio of one hermetic compressor is 0.
．． The reason for selecting 5 to 1.5 will be explained later.

32 is a high pressure related to a first control valve that is provided in the middle of (15) of the auxiliary compression element discharge pipe 5 that connects the discharge side of the auxiliary compression element 3A and the high pressure gas pipe 6, and that stops the flow of refrigerant during capacity control. The side check valve 42 is the main compression element 2A
A low-pressure side check valve 33, which is a second control valve that stops the flow of refrigerant during capacity control, is provided in the middle of the main compression element suction pipe 12 that connects the suction side of the main compression element with the low-pressure gas pipe 11.
It is an intermediate mixer inflow pipe that guides the discharged gas refrigerant from the auxiliary compression element 3A to the intermediate mixer 34 during medium capacity control,
This intermediate mixer inflow pipe 33 connects the auxiliary compression element side of the high pressure side check valve 32 and the intermediate mixer 34, and has a two-way valve for preventing inflow on the auxiliary compression element side (i.e., upstream side) in the middle. 35 and a check valve 36 for preventing backflow of condensed refrigerant on the intermediate mixer side.

37 is a heat exchanger provided at the outlet of this intermediate mixer inlet pipe 33. 38 is a gas outflow pipe that connects the main compression element side of the low-pressure side check valve 42 and the intermediate mixer 34, and is provided with a two-way valve 39 for preventing outflow in the middle. Reference numeral 40 indicates the main compression element side of the outflow prevention two-way valve 39 on the gas outflow pipe 3B, and the intermediate mixer inflow pipe 3.
3. Inflow (16) This is a bypass pipe that connects the two-way blocking valve 35 and the condensed refrigerant backflow blocking check valve 36, and is provided with a bypass control valve 41 in the middle.

Here, the theoretical displacement ratio of the hermetic compressor IA is 0.5 to
According to the research of the present inventors, which explains the reason why 1.5 was selected, during capacity control, the auxiliary compression element 3A and the main compression element 2
When humans are connected in series and refrigerant is also allowed to flow through the auxiliary compression element 3A, the theoretical displacement ratio is 0.5 (corresponds to a ratio of maximum capacity and capacity during capacity control of 3:1). A nearly satisfactory coefficient of performance can be obtained, but when the displacement ratio is lower than that, the coefficient of performance drops significantly. On the other hand, when the theoretical displacement ratio is 1.5, the ratio between the maximum capacity and the capacity during capacity control is 1.7.
:1, but in a normal capacity control refrigeration cycle, the ratio 1.7:1 is the lower limit, and if it is less than this, it is not called capacity control. Therefore, the upper limit of the theoretical displacement ratio must be 1.5, and in conjunction with the above, by setting the theoretical displacement ratio in the range of 0.5 to 1.5, the invention The following effects can be obtained.

(17) The operation of the pump type room air conditioner configured as above will be explained. The operating method is large-capacity controlled operation for both heating and cooling operations.

Two-stage capacity control of medium capacity control operation is possible, but since capacity control is exactly the same for heating operation and cooling operation, the heating operation will be explained below as an example.

The heating operation can be performed in the following three ways.

(1) High capacity operation (when capacity is not controlled) Close the inflow prevention three-way valve 35 and the outflow prevention two-way valve 39 (OFF), open the bypass control valve 41 (ON), and operate the hermetic compressor IA. . The refrigerant exiting the two main compression elements and the auxiliary compression element 3A is transferred to the main compression element discharge pipe 4. It passes through the auxiliary compression element discharge pipe 5, joins the high pressure gas pipe 6, and is connected to the indoor heat exchanger 8 by means of the four-way switching valve 7. Indoor heat exchanger side pressure reducer 43. Intermediate mixer 34. Outdoor heat exchanger side pressure reducer 44
．． It flows in the order of the outdoor heat exchanger 10 through the four-way switching valve 7 from the low pressure gas pipe 11 to the main compression element suction pipe 12 and the auxiliary compression element suction pipe 13 to the two main compression elements and the auxiliary compression element 3.
Return to A and repeat the cycle. At this time, since the inflow blocking two-way valve 35 is closed, the gas discharged from the auxiliary compression element 3A does not flow into the intermediate mixer 34. Furthermore, since the outflow prevention two-way valve 39 is also closed, no gas refrigerant flows out from the intermediate mixer 34 to the main compression element 2A. Furthermore, since the bypass control valve 41 is open, the pressure on the bypass pipe 40 side of the condensed refrigerant backflow prevention check valve 36 becomes equal to the pressure on the suction side of the main compression element 2A. Since this pressure is the lowest pressure in the refrigeration cycle, backflow from the intermediate mixer 34 is completely prevented. Therefore, the intermediate mixer 34 is
In this state, nothing is working.

In this way, the two main compression elements and the auxiliary compression element 3A are in parallel operation, and the capacity of the refrigeration cycle is maximized.

(2) Large capacity control operation (small capacity operation) Open the inflow prevention two-way valve 35 and bypass control valve 41 (
ON), and the hermetic compressor IA is operated with the outflow prevention two-way valve 39 closed (19) (OF'F).

The gas refrigerant discharged from the auxiliary compression element 3A passes through the inflow prevention two-way valve 35 and the bypass control valve 41, is sucked into the main compression element 2A from the main compression element suction pipe 12, passes through the main compression element discharge pipe 4, and is then discharged to high pressure. The gas flows from the gas pipe 6 to the four-way switching valve 7, and then flows in the same manner as in the cycle (1) above.

At this time, when the suction pressures of the main compression element 2A and the auxiliary compression element 3A are compared, the pressure on the suction side of the main compression element 2A becomes equal to the pressure on the discharge side of the auxiliary compression element 3A due to the flow of the refrigerant described above. higher than the suction side pressure of element 3A. Therefore, the low pressure side check valve 42 makes the suction sides of the two main compression elements and the auxiliary compression element 3A completely independent. Also, when comparing the discharge pressures of the two main compression elements and the auxiliary compression element 3A, it is found that due to the above-described flow of refrigerant, the discharge pressure of the auxiliary compression element 3A
Since the pressure on the discharge side of the main compression element 2A is equal to the pressure on the suction side of the main compression element 2A, the pressure on the discharge side of the main compression element 2A is lower than that of the main compression element 2A. Therefore, the high pressure side check valve 32 also makes the discharge sides of the main compression element 2A and the auxiliary compression element 3A completely independent (20).

In this way, the auxiliary compression element 3A is connected in series with the main compression element 2A, and the capacity of the refrigeration cycle is reduced to a minimum.

(3) Medium capacity control operation (live capacity operation) Open the two-way valve 35 for inflow prevention and the two-way valve 39 for outflow prevention (
ON), and the hermetic compressor IA is operated with the bypass control valve 41 closed (OF'F).

The gas refrigerant discharged from the auxiliary compression element 3A is transferred to the inflow prevention two-way valve 35. The condensed refrigerant flows into the intermediate mixer 34 through the check valve 36 for preventing backflow. Here, heat is radiated by the indoor heat exchanger 8,
After the two-phase refrigerant is condensed and reduced in pressure to a pressure between the condensation pressure and the evaporation pressure in the indoor heat exchanger side pressure reducer 43 and mixed in the heat exchanger 37 and mixed, a two-way valve for preventing only the gas refrigerant from flowing out is removed. 39, is sucked into the main compression element 2A from the main compression element suction pipe 12, passes through the main compression element discharge pipe 4, goes from the high pressure gas pipe 6 to the four-way switching valve 7, and then the part related to the intermediate mixer 34. The flow is the same as the cycle (2) above except for.

(21) At this time, the main compression element suction pipe 12 and the auxiliary compression element suction pipe 13, and the main compression element discharge pipe 4 and the auxiliary compression element discharge pipe 5, for the same reason as explained in the cycle (2) above, are independent of each other.

In this way, the auxiliary compression element 3A
The refrigeration cycle is connected in series with the two main compression elements via the refrigeration cycle, and the capacity of the refrigeration cycle is intermediate between the cycles (1) and (2).

Here, the capacity of the cycle (2) (during large capacity control operation) and the capacity of this cycle (3) (during medium capacity control operation) will be explained using the Mollier diagram in Fig. 6. do.

In FIG. 6, the horizontal axis represents enthalpy, and the vertical axis represents pressure. The solid line represents the cycle (3), and the broken line represents the cycle (2).

First, the cycle (3) will be explained.

A is the state of the refrigerant sucked into the auxiliary compression element 3A, and after compression it is in the state b. The refrigerant in state b is led into the intermediate mixer 34, where it is mixed with the refrigerant (state C) that has been condensed in the indoor heat exchanger (22) 8 and depressurized in the indoor heat exchanger side pressure reducer 43. , the liquid refrigerant is in the state d, and the gas refrigerant is in the state e.

The liquid refrigerant in the state d is depressurized by the outdoor heat exchanger side pressure reducer 44, and then evaporated in the outdoor heat exchanger 10, returning to the state a.

The gas refrigerant in the state e is guided from the gas outflow pipe 38 of the intermediate mixer 34 to the main compression element 2A, and after compression becomes the state f, and is led to the indoor heat exchanger 8.

On the other hand, in the cycle (2), the refrigerant in the state a is compressed by the auxiliary compression element 3A until it reaches the state b, which is the same as the cycle (3) above. The main compression element 2 is controlled by the valve 35 and the bypass control valve 41.
It is guided to A and is compressed, resulting in state g.

After that, it is condensed in the indoor heat exchanger 8, and then the outdoor heat exchanger 1
However, since there is no mixing or heat exchange in the intermediate mixer 34, the enthalpy difference of evaporation is h in the figure, and the cycle (3) is larger by Δh (23). A large enthalpy difference of evaporation is equivalent to a correspondingly large capacity, and the cycle (3) is equivalent to the cycle (1).
The ability is between the ability of the cycle and the ability of the cycle (2).

The effects of the heat pump type room near conditioner of this embodiment described above will be described.

[I] The aforementioned (1) large capacity operation, (2) large capacity controlled operation.

(3) Capacity control in three stages of medium capacity control operation is possible.

This will be explained using FIG. 7. FIG. 7 shows changes in heating load (dotted chain line 45 in the diagram) and heating capacity (solid line in the diagram) when outside air temperature is plotted on the horizontal axis. This corresponds to FIG.

In the figure, the heating capacity is the cycle described in (1) above.

The heating capacity R indicates the heating capacity of the cycle (3), and the heating capacity M indicates the heating capacity of the cycle (2).

When the outside temperature is in range G, cycle (1) is operated continuously, and when it is in range J, cycle (2) is operated intermittently, which is almost the same as the conventional technology, but (24) In the case of range H, the cycle (1) and cycle (3) are switched, and in the case of range I, the cycle (3) and (
2) The cycle switching operation is performed, and there is less variation in capacity at the time of switching than in the case of the prior art, and the temperature variation in the air-conditioned room is correspondingly reduced, allowing fine control.

[In the conventional heat pump type room near conditioner according to the old Fig. 1, the auxiliary compression element 3, which does not perform work, was operated in a vacuum during capacity control, so the auxiliary compression element 3
However, in this embodiment, the refrigerant was also made to flow through the auxiliary compression element 3A, which does not perform any work. Therefore, the leakage of the auxiliary compression element 3A is as small as when no capacity control is performed, and unlike the conventional case, the leakage increases due to capacity control and this leakage reduces the compression adiabatic efficiency. There isn't.

The adiabatic compression efficiency of the hermetic compressor IA in this embodiment, for example, during large capacity control operation is as indicated by the dashed-dotted line F in FIG. 4, and that of the conventional hermetic compressor 1 in FIG. Heat insulation during capacity control (25) Improved compared to compression efficiency E. The reason why the adiabatic compression efficiency F is lower than the adiabatic compression efficiency without capacity control is because the adiabatic compression efficiency is reduced by the fixed loss due to the brush stroke loss of the hermetic compressor IA. However, the capacity control reduces the capacity of the hermetic compressor IA, and therefore the heat exchanger becomes relatively large, so the decrease in the coefficient of performance of the refrigeration cycle is extremely small.

[■] During capacity control, the main compression element 2A is on the higher pressure side than the auxiliary compression element 3A, but by making the discharge chambers of the two main compression elements into the chamber 15, the pressure inside the chamber 15 will be higher than that of the auxiliary compression element 3A. The pressure will be higher than that of the pressure chamber. Therefore, the refrigerating machine oil (not shown) stored in the chamber 15 can permeate all the compression elements to form an airtight seal, thereby minimizing leakage from the main compression element 2A and the auxiliary compression element 3A. I can do it.

In addition, in this embodiment, the main compression element 2A, the auxiliary compression element 3A
Although the hermetic compressor IA that is housed in the chamber 15 has been described, the present invention is not only applicable to a heat pump type room near conditioner using a hermetic (26) closed compressor. It can also be applied to heat pump type room near conditioners that use open type compressors.

Further, in this embodiment, check valves (high pressure side check valve 32 and low pressure side check valve 42) are used as the first control valve and the second control valve, but two-way valves are used. You can also do this.

In particular, when the theoretical discharge amount of the auxiliary compression element 3A, which is on the low pressure side, is approximately 1.0 times or less than the theoretical discharge amount of the main compression element 2A, which is on the high pressure side, the low pressure side check valve 42 in FIG. It is necessary to use a two-way valve instead.

The reason is that during capacity control, the suction side of the main compression element 2A has the same pressure as the discharge side of the auxiliary compression element 3A, but the main compression element 2A is thicker than the auxiliary compression element 3A.
This is because the suction side pressure of the auxiliary compression element 3A>discharge side pressure of the auxiliary compression element 3A becomes the suction side pressure of the main compression element 2A, and the flow of the refrigerant cannot be stopped by the check valve.

Further, in this embodiment, the intermediate mixer inflow pipe 33゛ (27
), but this heat exchanger 37 may be omitted, or alternatively, the intermediate mixer 34 may be filled with something useful for heat exchange, such as steel wool. But that's fine.

〔Effect of the invention〕

As described above in detail, according to the present invention, it is possible to provide a heat pump room near conditioner that allows fine capacity control and has an excellent coefficient of performance during capacity control.

[Brief explanation of the drawing]

FIG. 1 is a cycle configuration diagram showing an example of a conventional sitar heat pump type room near conditioner using a compressor with two compression elements, and FIG. 2 is a sectional view showing details of the compressor in FIG. 1. Figure 3 is a heating capacity diagram showing the relationship between the heating capacity and outside air temperature of the heat pump room near conditioner shown in Figure 1. An adiabatic compression efficiency diagram showing a comparison of compression efficiencies, FIG. 5 is a cycle configuration diagram of a heat pump room near conditioner (28) according to an embodiment of the present invention, and FIG. 6 is an adiabatic compression efficiency diagram according to FIG. A Mollier diagram showing the state of the refrigeration cycle during capacity control of the heat pump room near conditioner, and FIG. 7 is a heating capacity showing the relationship between the heating capacity of the heat pump room near conditioner and the outside air temperature according to FIG. It is a line diagram. IA...Hermetic compressor, 2A...Main compression element, 3A
...Auxiliary compression element, 5...Auxiliary compression element discharge pipe, 6...High pressure gas piping, 8...Indoor heat exchanger, 1
0...Outdoor heat exchanger, 11...Low pressure gas piping, 1
2... Main compression element suction pipe, 15... Chamber,
32...High pressure side check valve, 33...Intermediate mixer inflow pipe, 34...Intermediate mixer, 35...Two-way valve for preventing inflow, 36...Return check for preventing backflow of condensed refrigerant Valve, 38...
・Gas outflow pipe, 39...Two-way valve for outflow prevention, 40
... Bypass pipe, 41 ... Bypass control valve, 4
2...Low pressure side check valve, 43...Indoor heat exchanger side pressure reducer, 44...Outdoor heat exchanger side pressure reducer. Agent Patent attorney Kosaku Fukuda (and 1 other person) (29) 1,3 3, 5 Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4, Figure 4. →

Claims (1)

[Claims] 1. A compressor having a main compression element and an auxiliary compression element. A heat pump type room near conditioner that circulates refrigerant to the high pressure gas piping, condenser, pressure reducer, evaporator, low pressure gas piping, and compressor, and controls the capacity of the refrigeration cycle when the load becomes small. In this method, the pressure reducer is divided into a condenser-side pressure reducer and an evaporator-side pressure reducer, an intermediate mixer is arranged between these two pressure dividers, and the theoretical displacement of the auxiliary compression element is calculated from the theoretical displacement of the main compression element. A first control to stop the flow of refrigerant at the time of capacity control, which is 0.5 to 1.5 times the displacement amount, and is placed in the middle of the auxiliary compression element discharge pipe that connects the discharge side of the auxiliary compression element and the high-pressure gas pipe. A second control valve that stops the flow of refrigerant during capacity control is provided in the middle of the main compression element suction pipe that connects the suction side of the main compression element and the low-pressure gas pipe, and the second control valve is auxiliary to the first control valve. In the middle of the intermediate mixer inlet pipe connecting the compression element side and the intermediate mixer,
A two-way valve for preventing inflow on the side of the auxiliary compression element and a check valve for preventing backflow of condensed refrigerant on the side of the intermediate mixer are respectively provided, and a gas connecting the main compression element side of the second control valve and the intermediate mixer is provided. A two-way valve for preventing outflow is provided in the middle of the outflow pipe, and the two-way valve for preventing inflow is provided on the main compression element side of the two-way valve for preventing outflow on the gas outflow pipe, and the two-way valve for preventing inflow on the intermediate mixer inflow pipe. By providing a bypass control valve in the middle of the bypass pipe that connects the condensed refrigerant backflow prevention check valve, the auxiliary compression element is connected in series with the main compression element during large capacity control, and the small A heat pump type room near conditioner characterized in that, during capacity control, the auxiliary compression element is connected in series with the main compression element via the intermediate mixer. 2 The first control valve is a high-pressure side check valve that allows flow only from the auxiliary compression element toward the high-pressure gas piping, and the second control valve is a low-pressure side check valve that allows flow from the low-pressure gas piping only toward the main compression element. A heat pump type room near conditioner according to claim 1. 3. The compressor is a hermetic compressor having a main compression element and an auxiliary compression element housed in a chamber, and the discharge chamber of the main compression element is the chamber, according to claim 1. Heat pump type room near conditioner.