JP2003207237A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform efficient heating operation by preventing partial frosting of outdoor heat exchangers. <P>SOLUTION: A main circuit is constituted by successively and annularly connecting a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an orifice device 4, the first outdoor heat exchanger 5, a control valve 9, and the second outdoor heat exchanger 7. A refrigerating cycle is constituted by arranging a second orifice device 8 in parallel to a control valve 6. The size of the second outdoor heat exchanger 7 is formed larger than the first outdoor heat exchanger 5. The control valve 9 is composed of a valve element 10, a valve seat 11, a bias spring 12, a shape memory alloy spring 13, and a first passage 14. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a refrigerating apparatus using a non-azeotropic mixed refrigerant.

[0002]

2. Description of the Related Art In recent years, a mixed refrigerant has been attracting attention as an alternative refrigerant for a refrigerating device in accordance with the regulations of CFC and HCFC. An example of a conventional refrigeration system using a non-azeotropic mixed refrigerant will be described below with reference to the drawings.

FIG. 21 shows a refrigeration cycle of a conventional refrigeration system using a non-azeotropic mixed refrigerant.

In FIG. 21, reference numeral 50 is a compressor, 51 is a four-way valve, 52 is an indoor heat exchanger, 53 is a throttle device, and 54 is an outdoor heat exchanger, which are sequentially connected in a ring to form a main circuit.

The operation of the refrigerating apparatus constructed as above will be described below.

The high-temperature and high-pressure refrigerant vapor compressed by the compressor 50 radiates heat in the indoor heat exchanger 52 via the four-way valve 51 and is condensed and liquefied. Then, the expansion device 53 decompresses and expands to a low-temperature low-pressure refrigerant. And the outdoor heat exchanger 5
After absorbing heat by 4 and evaporating and vaporizing, it becomes a low-temperature low-pressure refrigerant vapor, is compressed again by the compressor 50, and the refrigerating cycle is repeated (for example, JP-A-3-13766).

[0007]

The outdoor heat exchanger during heating operation functions as an evaporator, and the refrigerant changes in a gas-liquid two-phase state. In the case of a single refrigerant, the inlet refrigerant temperature and the outlet refrigerant temperature of the heat exchanger are the same, but the non-azeotropic mixed refrigerant has non-isothermal properties, and the temperature increases as the dryness of the refrigerant increases, so the outdoor heat The refrigerant temperature at the inlet of the exchanger is lower than the refrigerant temperature at the outlet of the outdoor heat exchanger. Therefore, in the above-mentioned configuration, during the heating operation, even if the outdoor temperature is such that the outdoor heat exchanger does not frost in the case of a single refrigerant, the non-azeotropic mixed refrigerant causes frost formation at the inlet of the outdoor heat exchanger. It is possible that the heating capacity will decrease.

The present invention is intended to solve the above-mentioned problems of the conventional example, and it is an object of the present invention to prevent partial frost formation on the outdoor heat exchanger and enable efficient heating operation.

[0009]

In order to solve the above problems, the present invention provides a control valve between a first outdoor heat exchanger and a second outdoor heat exchanger, and a second throttle in parallel with the control valve. A first outdoor heat exchanger refrigerant temperature detecting means for detecting and outputting the refrigerant temperature of the first outdoor heat exchanger is provided with a device, and the first outdoor heat exchanger refrigerant temperature and the set temperature are compared with each other to obtain a control signal. A storage means storing an output mode for controlling opening and closing of a control valve; a selection means for selecting one of the output modes of the storage means according to an output signal generated from the comparison means; A valve control device is provided which is composed of output means for opening and closing the control valve according to the output mode of the storage means. When the control valve operates under a temperature condition in which the first outdoor heat exchanger causes frost formation, the refrigerant is transferred to the second expansion device by the second expansion device and the valve control device which are provided in parallel with the control valve. Flowing, a differential pressure is generated between the refrigerant before and after the second expansion device, the pressure of the first outdoor heat exchanger is higher than the pressure of the second outdoor heat exchanger, and the temperature of the refrigerant flowing through the first outdoor heat exchanger is high. Therefore, frost formation at the inlet of the first heat exchanger can be prevented, and efficient heating operation can be performed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In order to solve the above-mentioned problems, the inventions of claims 1, 5 and 6 are provided with a control valve, a valve control device and a second throttle device in parallel with the control valve. Is. As a result, when the control valve operates under a temperature condition in which the first outdoor heat exchanger causes frost formation, the refrigerant flows into the second expansion device, and a differential pressure is generated between the refrigerant before and after the second expansion device. Since the pressure of the first outdoor heat exchanger is higher than the pressure of the second outdoor heat exchanger and the temperature of the refrigerant flowing through the first outdoor heat exchanger is high, frost formation at the inlet of the first heat exchanger can be prevented. This enables efficient and efficient heating operation.

Further, the invention according to claims 2, 3, and 4 is a control in which a pressure reducing mechanism is provided between the first outdoor heat exchanger and the second outdoor heat exchanger and a shape memory alloy spring is built in. By providing the valve, the shape memory alloy spring transforms under the condition that the outdoor heat exchanger causes frosting and is bent by being biased by the bias spring, pressing the valve body against the valve seat to narrow the flow path of the refrigerant, A differential pressure is generated between the refrigerant before and after the control valve, the pressure of the first outdoor heat exchanger becomes higher than the pressure of the second outdoor heat exchanger, and the temperature of the refrigerant flowing through the first outdoor heat exchanger becomes high. It is possible to prevent frost formation at the inlet of the heat exchanger, eliminate the need for a separate expansion device and valve control device, and enable efficient heating operation with a simpler configuration.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a refrigeration cycle diagram in a first embodiment of the refrigerating apparatus of the present invention.

In FIG. 1, 1 is a compressor, 2 is a four-way valve,
3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 6 is a control valve, and 7 is a second outdoor heat exchanger, which are sequentially connected in an annular fashion to form a main circuit, and a control valve A second expansion device 8 is provided in parallel with 6 to form a refrigeration cycle, and the size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. Reference numeral 22 is a valve control device that controls the opening and closing of the control valve 6, and 24 is a refrigerant temperature detector that detects the refrigerant temperature of the first outdoor heat exchanger 5 and outputs a temperature detection signal.

FIG. 2 is an electric circuit diagram showing the electric connection of the refrigerating apparatus shown in FIG. In the figure, 24 is the first outdoor heat exchanger 5
Refrigerant temperature detector for detecting the refrigerant temperature of
A / D converter, 26 is a microcomputer (hereinafter referred to as LS
I)), and has an input circuit 27, a CPU 28, a memory 29, and an output circuit 30. In the input circuit 27,
The output of the refrigerant temperature detector 24 of the first outdoor heat exchanger 5 is A
It is input via the / D converter 25. Reference numeral 31 is an electromagnetic coil, which operates the opening and closing of the control valve 6 by the output of the output circuit 30.

The block diagram shown in FIG. 3 and the electric circuit diagram shown in FIG. 2 will now be described. The refrigerant temperature detector 24 of the first outdoor heat exchanger 5 of FIG. 2 corresponds to the first outdoor heat exchanger of FIG. The refrigerant temperature detecting means 5 for detecting and outputting the refrigerant temperature, the LSI 26 in FIG. 2 compares the value detected by the refrigerant temperature detecting means in FIG. 3 with a set value, and outputs a control signal; It corresponds to a storage unit that stores an output mode for controlling the opening and closing of the valve 6, and a selection unit that selects one of the output modes of the storage unit according to the output signal generated from the comparison unit. The electromagnetic coil 31 that opens and closes the control valve 6 in FIG. 2 corresponds to the output unit in FIG.

The structure and operation of the control circuit having the above-described structure when the refrigeration system is in operation will be described with reference to FIG. Figure 4 is LS
It is a flowchart which shows the program of the refrigeration apparatus memorize | stored in the memory 29 of I26.

When the operation instruction is given, the operation of the refrigerating apparatus is started, and at the same time, step 40 shown in FIG. 4 is executed to detect the refrigerant temperature T _{e of} the first outdoor heat exchanger 5, and step 41
Memory in performs a comparison operation between the refrigerant temperature T _e and the set temperature T ₂ of the first outdoor heat exchanger 5 (e.g. -2 ° C.), the flow proceeds to step 42 by determining "NO" if T _e ≧ T ₂ The first output mode of the memory circuit is selected by the built-in selection means 29, the electromagnetic coil 31 is not energized, and the control valve 6 is left open to return to step 40. That is, the control valve 6 remains open under the condition that frost does not grow at the inlet of the first outdoor heat exchanger 5.

Next, when the outdoor temperature drops,
Cooling of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 that operate.
The temperature of the medium becomes lower than the outdoor temperature, and heat is absorbed from the atmosphere. This
If a non-azeotropic mixed refrigerant is used here, because of its non-isothermal property,
The refrigerant temperature rises as the dryness of the refrigerant increases.
Therefore, from the center of the first outdoor heat exchanger 5 to the outlet,
Even when the temperature of the two outdoor heat exchangers 7 is 0 ° C or higher, the first chamber
The inlet of the external heat exchanger 5 drops to 0 ° C., and the first outdoor heat exchanger 5
Begins to frost only at the entrance of. And T_e<T₂Next to
When the temperature condition in which frost grows on the first outdoor heat exchanger 5 is reached
A "YES" determination is made in step 41, and step 4
In step 3, the selection means of the memory 29 makes the memory circuit first.
2 output mode is selected, output from the output circuit 30
The electromagnetic coil 31 is energized and the control valve 6 is closed. Control valve
When 6 is closed, the refrigerant flows to the second expansion device 8 and the second expansion device 8.
A pressure difference occurs around 8. At this time, the second outdoor heat exchanger 7
Is larger than the first outdoor heat exchanger 5, so the second chamber
The refrigerant pressure of the external heat exchanger 7 does not change so much and the first outdoor heat exchanger
The refrigerant pressure of the exchanger 5 rises, and the refrigerant of the first outdoor heat exchanger 5
The temperature also rises. Then, in step 44, the first outdoor heat exchange
Refrigerant temperature T of the converter 5 _eIs detected, and the first chamber is detected in step 45.
Refrigerant temperature T of the external heat exchanger 5_eAnd the first set temperature T ₁(For example
(1 ° C). T in step 45_e<T₂so
If there is, a “NO” determination is made and the operation proceeds to step 46. Ste
At step 46, the refrigerant temperature T of the first outdoor heat exchanger 5_eAnd the third
Set temperature T₃(For example, -5 ° C)_e
≧ T₁If so, return to step 43 with a “NO” determination.
The second output mode of the memory circuit continues to be selected and the output
A signal is output from the path 30 and the electromagnetic coil 31 is energized.
The control valve 6 remains closed and the first outdoor heat exchanger 5
The frost on it can be thawed. Then, as the outdoor temperature rises, T_e
≧ T₁If so, the routine proceeds to step 42, where the first memory circuit
Output mode is selected and the electromagnetic coil 31 is energized.
Instead, the control valve 6 is opened, and the process returns to step 40. Therefore, the
1 Frost in the outdoor heat exchanger 5 does not melt and grow.

Further, when the outside air temperature decreases and frost is grown on the entire first and second outdoor heat exchangers 5, 7,
In step 46, a comparison calculation is performed between the refrigerant temperature T _e of the first outdoor heat exchanger 5 and the third set temperature T _3, and when T _e ≧ T ₃ , the first output mode of the memory circuit is selected and the electromagnetic coil Three
1 is not energized and the control valve 6 opens. Since the refrigerant does not flow through the second expansion device 8 and is not depressurized, there is no difference in refrigerant temperature before and after the control valve 6. In this way, since there is no pressure difference before and after the control valve 6, it is possible to effectively use the first and second outdoor heat exchangers 5 and 7 and enable efficient heating operation.

In this way, it is possible to prevent frost formation on the outdoor heat exchanger and to perform efficient heating operation.

In the above description, the control valve 6 and the second throttle device 8 provided in parallel with the control valve 6 are used. However, when the control valve 6 is provided with a throttle mechanism and the control valve 6 operates, the control valve 6 is operated.
If the refrigerant flow path inside is narrowed and a pressure difference is generated before and after the control valve 6, frost formation on the outdoor heat exchanger can be prevented and efficient heating operation can be performed with a simpler configuration.

(Embodiment 2) In FIG. 5, 1 is a compressor,
2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 9 is a control valve, and 7 is a second outdoor heat exchanger, which are sequentially connected in an annular shape to form a main circuit. The refrigeration cycle is configured by providing the second expansion device 8 in parallel with the control valve 9. The size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. Here, what is different from the first embodiment is that there is no refrigerant temperature detector 24 and valve control device 22 that detect the temperature of the first heat exchanger and output a temperature detection signal, and the structure of the control valve 9. is there.

FIG. 6 is a sectional view of the control valve 9.

In FIG. 6, 10 is a valve element, 11 is a valve seat,
12 is a bias spring, 13 is a first shape memory alloy spring, 1
Reference numeral 4 is a first flow path.

FIG. 7 shows the temperature of the first shape memory alloy spring 13.
It is a strain curve (hysteresis curve). There is a temperature difference between the operating temperatures during heating and cooling, that is, temperature hysteresis, and the first shape memory alloy spring 13 has a transformation temperature T during heating.
1 (eg 0 ° C.), the transformation temperature T2 (eg −
2 ℃).

The operation of the control valve 9 in the above structure will be described.

The first shape memory alloy spring 13 expands when the temperature exceeds the set transformation temperature T1 and pushes the valve body 10 against the spring force of the bias spring 12 to open the first flow path 14 and the refrigerant. Flows through the first flow path 14 without flowing through the second expansion device 8. On the other hand, the first shape memory alloy spring 13 has the set transformation temperature T
When it becomes lower than 2, the valve body 1 is pushed by the bias spring 12.
0 corresponds to the valve seat 11, and the first flow path 14 is closed.
Therefore, the refrigerant can flow only through the second expansion device 8, is decompressed, and the temperature of the refrigerant is lowered.

Next, the operation of the control valve 9 during operation of the refrigeration system will be described.

During the heating operation, when the outdoor air temperature is high and the temperature of the refrigerant flowing through the control valve 9 is higher than the set transformation temperature T2, the first shape memory alloy spring 13 resists the spring force of the bias spring 12 and the valve body. The first flow path 14 is opened because the bias spring 12 is compressed by pushing 10. Since the refrigerant does not flow to the second expansion device 8, it is not decompressed, and there is no difference in refrigerant temperature before and after the control valve 9.

However, when the outdoor air temperature becomes low, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as evaporators become lower than the outdoor air temperature, and the heat is absorbed from the atmosphere, but the non-azeotropic mixed refrigerant. With the use of, due to its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C or higher, the inlet of the first outdoor heat exchanger 5 is lowered to 0 ° C or lower and Frost starts only at the entrance of the outdoor heat exchanger 5. The temperature of the refrigerant flowing through the control valve 9 is the set transformation temperature T of the first shape memory alloy spring 13.
When it becomes lower than 2, the first shape memory alloy spring 13 is pushed by the bias spring 12 to move the valve body 10 to the valve seat 11 as shown in FIG.
Then, the first flow path 14 is closed. Refrigerant is second
Only the expansion device 8 can flow, and a pressure difference occurs before and after the second expansion device 8. At this time, since the size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5, the refrigerant pressure of the second outdoor heat exchanger 7 does not change so much and the first outdoor heat exchanger 5
Refrigerant pressure rises, and the inlet refrigerant temperature of the first outdoor heat exchanger 5 also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not thaw and grow.

In addition, when the control valve 9 is operating, the refrigerant temperature of the control valve 9 becomes the second temperature in a state in which frost does not occur in the first outdoor heat exchanger 5 due to an increase in outdoor temperature. 1 When it becomes higher than the set transformation temperature T1 of the shape memory alloy spring 13,
As shown in FIG. 6, the first shape memory alloy spring 13 is transformed, the extension bias spring 12 is compressed, the valve body 10 is separated from the valve seat 11, and the first flow path 14 is opened. Since the refrigerant does not flow through the second expansion device 8 and is not depressurized, there is no difference in refrigerant temperature before and after the control valve 9.

As described above, frost formation on the outdoor heat exchanger is prevented,
Efficient heating operation becomes possible.

(Embodiment 3) In FIG. 9, 1 is a compressor,
2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 18 is a control valve, and 7 is a second outdoor heat exchanger, which are sequentially connected in an annular shape to form a main circuit. Configure and control valve 18
A second expansion device 8 is provided in parallel with the above to form a refrigeration cycle. The size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. Here, what is different from the second embodiment is the structure of the control valve 18.

FIG. 10 is a sectional view of the control valve 18.

In FIG. 9, 10 is a valve element, 11 is a slidable valve seat, 12 is a first bias spring, 13 is a first shape memory alloy spring, 14 is a first flow path, and 15 is a second bias spring. , 16 are second shape memory alloy springs, and 17 is a stopper for stopping the movement of the valve body 10.

FIG. 11 is a temperature-strain curve (hysteresis curve) of the first shape memory alloy spring 13 and the second shape memory alloy spring 16. There is a temperature difference between the operating temperature at the time of heating and the operating temperature at the time of cooling, that is, temperature hysteresis, and the first shape memory alloy spring 13 has a transformation temperature T1 (for example, 0 ° C.) during heating
Adjust to the transformation temperature T2 (eg -2 ° C) during cooling,
The shape memory alloy spring 16 is adjusted to a transformation temperature T3 (for example, −3 ° C.) during heating and a transformation temperature T4 (for example, −5 ° C.) during cooling.

The operation of the control valve 18 in the above structure will be described.

The first shape memory alloy spring 13 expands when the temperature exceeds the set transformation temperature T1, pushes the valve body 10 against the spring force of the first bias spring 12, and opens the first flow path 14. Become. On the other hand, when the first shape memory alloy spring 13 becomes lower than the set transformation temperature T2, the valve body 10 pushed by the first bias spring 12 hits the valve seat 11, and the first flow passage 14 is closed. Therefore, the refrigerant can only flow through the second expansion device 8, the pressure is reduced before and after the second expansion device 8, and the temperature of the refrigerant decreases. Further, when the second shape memory alloy spring 16 becomes lower than the set transformation temperature T4, the second bias spring 15 is released.
It cannot withstand the spring force of and contracts. The valve seat 11 is pushed by the second bias spring 15, but the valve body 10 is stopped by the stopper 17, so that the moving distance of the valve seat 11 becomes longer than the moving distance of the valve body 10.
If the forces of the bias spring 12, the first shape memory alloy spring 13, the second bias spring 15, and the second shape memory alloy spring 16 are adjusted, the first flow path 14 is opened.

Next, the operation of the control valve 18 during operation of the refrigeration system will be described.

During the heating operation, the outdoor temperature is high and the control valve 18
When the temperature of the refrigerant flowing through is higher than the set transformation temperature T2,
As shown in FIG. 10, the first shape memory alloy spring 13 pushes the valve body 10 against the spring force of the first bias spring 12 to compress the first bias spring 12, and the second shape memory alloy spring 16 is Since the valve seat 11 is pushed against the spring force of the second bias spring 15 and the second bias spring 15 is compressed, the first flow path 14 is opened. Since the refrigerant does not flow through the second expansion device 8, the refrigerant is not decompressed, and there is no difference in refrigerant temperature before and after the control valve 18.

However, when the outdoor air temperature becomes low, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as evaporators become lower than the outdoor air temperature, and the heat is absorbed from the atmosphere, but the non-azeotropic mixed refrigerant. With the use of, due to its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C or higher, the inlet of the first outdoor heat exchanger 5 is lowered to 0 ° C or lower and Frost starts only at the entrance of the outdoor heat exchanger 5. When the temperature of the refrigerant flowing through the control valve 18 is lower than the set transformation temperature T2 of the first shape memory alloy spring 13 and higher than the set transformation temperature T4 of the second shape memory alloy spring 16, the first shape memory is set as shown in FIG. The alloy spring 13 is pushed by the first bias spring 12 to push the valve body 10 against the valve seat 11, and the second shape memory alloy spring 16 pushes the valve seat 11 against the spring force of the second bias spring 15. Since the 2 bias spring 15 is compressed, the first flow path 14 is closed. As a result, the refrigerant can only flow through the second expansion device 8 and a pressure difference occurs before and after the second expansion device 8. At this time, the size of the second outdoor heat exchanger 7 is equal to that of the first outdoor heat exchanger 5.
Since it is larger, the refrigerant pressure in the second outdoor heat exchanger 7 does not change much, the refrigerant pressure in the first outdoor heat exchanger 5 rises, and the inlet refrigerant temperature of the first outdoor heat exchanger 5 also rises. Therefore,
Frost at the inlet of the first outdoor heat exchanger 5 does not thaw and grow.

Further, when the temperature of the refrigerant in the control valve 18 becomes lower than the set transformation temperature T4 of the second shape memory alloy spring 16, in a state where frost grows on the entire first and second outdoor heat exchangers 5, 7. Therefore, as shown in FIG. 13, the second shape memory alloy spring 16 cannot withstand the spring force of the second bias spring 15 and contracts, and the valve seat 11 is pushed by the second bias spring 15. Since the valve body 10 is stopped by the stopper 17, the first flow path 14 is opened. Refrigerant is second
Because the pressure does not flow through the expansion device 8 and the pressure is not reduced, there is no difference in refrigerant temperature before and after the control valve 18. Since there is no pressure difference before and after the control valve 18, the first and second outdoor heat exchangers 5,
It is possible to effectively use 7 to enable efficient heating operation.

Further, the temperature of the control valve 18 is low and is pushed by the first and second bias springs 12 and 15 as shown in FIG.
From the state in which the first and second shape memory alloy springs 13 and 16 are transformed and contracted and the control valve 18 is open, the temperature of the refrigerant flowing through the control valve 18 rises due to an increase in the outdoor temperature,
The temperature becomes higher than the set transformation temperature T3 of the second shape memory alloy spring 16, so that the first and second outdoor heat exchangers 5 and 7 are not frosted entirely, but only the inlet of the first outdoor heat exchanger 5 is frosted. In this state, as shown in FIG. 12, the second shape memory alloy spring 16
Transforms and expands, compresses the second bias spring 15 and presses the valve seat 11 against the valve body 10, so that the first flow path 14 is closed. As a result, the refrigerant can only flow through the second expansion device 8, and a pressure difference is generated before and after the second expansion device 8, the refrigerant pressure in the first outdoor heat exchanger 5 increases, and the refrigerant in the first outdoor heat exchanger 5 The inlet refrigerant temperature also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not thaw and grow.

Further, the temperature of the refrigerant flowing through the control valve 18 is set to the set transformation temperature T1 of the first shape memory alloy spring 13 in a state where the outdoor air temperature rises and frost does not occur on the first outdoor heat exchanger 5. When the temperature becomes higher, as shown in FIG. 10, the first shape memory alloy spring 13 transforms, expands, compresses the first bias spring 12, separates the valve body 10 from the valve seat 11, and the first flow path 14 is opened. Since the refrigerant does not flow through the second expansion device 8 and is not decompressed, there is no difference in refrigerant temperature before and after the control valve 18.

As described above, partial frosting of the outdoor heat exchanger is prevented, and in a state where the entire outdoor heat exchanger is frosted, the control valve is opened to enable efficient heating operation.

(Embodiment 4) FIG. 14 is a refrigerating cycle diagram in the fourth embodiment of the refrigerating apparatus of the present invention.

In FIG. 14, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 19 is a control valve, and 7 is a second outdoor heat exchanger. The second outdoor heat exchanger has a size larger than that of the first outdoor heat exchanger. here,
The difference from the second embodiment is that the structure of the control valve 19 has a pressure reducing mechanism.

FIG. 15 is a sectional view of the control valve 19.

In FIG. 15, 9 is a valve body, 10 is a valve body, 11 is a valve seat, 12 is a bias spring, 13 is a first shape memory alloy spring, 14 is a first flow passage, and 20 is a second flow passage. is there.

The temperature-strain curve (hysteresis curve) of the first shape memory alloy spring 13 is the same as that of the second embodiment shown in FIG.

The operation of the control valve 19 in the above structure will be described.

The first shape memory alloy spring 13 expands when the temperature exceeds the set transformation temperature T1 and pushes the valve body 10 against the spring force of the bias spring 12 to open the first flow path 14 and the refrigerant. Flows through the first flow path 14. On the other hand, when the first shape memory alloy spring 13 becomes lower than the set transformation temperature T2, it is pushed by the bias spring 12 and the valve body 10 hits the valve seat 11,
The first flow path 14 is closed. Therefore, since the refrigerant can flow only in the second flow path 20 and the flow path is narrowed,
The pressure is reduced and the temperature of the refrigerant is lowered.

Next, the operation of the control valve 19 during operation of the refrigeration system will be described.

During the heating operation, the outdoor temperature is high and the control valve 19
When the temperature of the refrigerant flowing through is higher than the set transformation temperature T2,
As shown in FIG. 15, the first shape memory alloy spring 13 pushes the valve body 10 against the spring force of the bias spring 12 and compresses the bias spring 12, so that the first flow path 14 is opened. The refrigerant is not decompressed by the control valve 19, and there is no difference in refrigerant temperature before and after the control valve 19.

However, when the outdoor air temperature becomes low, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as evaporators become lower than the outdoor air temperature, and the heat is absorbed from the atmosphere, but the non-azeotropic mixed refrigerant. With the use of, due to its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C or higher, the inlet of the first outdoor heat exchanger 5 is lowered to 0 ° C or lower and Frost starts only at the entrance of the outdoor heat exchanger 5. When the temperature of the refrigerant flowing through the control valve 19 becomes lower than the set transformation temperature T2 of the first shape memory alloy spring 13, the first shape memory alloy spring 13 is pushed by the bias spring 12 as shown in FIG. Is pressed against the valve seat 11, and the first flow path 14 is closed. Since the refrigerant can flow only in the second flow passage 20 and the flow passage is narrowed, a pressure difference occurs before and after the control valve 19. At this time, the second
Since the size of the outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5, the refrigerant pressure of the second outdoor heat exchanger 7 does not change much, and the refrigerant pressure of the first outdoor heat exchanger 5 increases. The inlet refrigerant temperature of the first outdoor heat exchanger 5 also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not melt and grow.

Further, with the control valve 19 operating,
In a state where the first outdoor heat exchanger 5 is not frosted due to an increase in the outdoor temperature, the refrigerant temperature of the control valve 19 is set to the first temperature.
When the temperature exceeds the set transformation temperature T1 of the shape memory alloy spring 13, the first shape memory alloy spring 13 transforms and compresses the extension bias spring 12 to separate the valve body 10 from the valve seat 11 as shown in FIG. The path 14 is opened. Since the refrigerant is not depressurized, there is no difference in refrigerant temperature before and after the control valve 19.

As described above, by using the control valve having the pressure reducing mechanism, the second expansion device becomes unnecessary, partial frosting of the outdoor heat exchanger can be prevented, and efficient heating operation can be performed.

(Embodiment 5) In FIG. 17, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, and 5
Is a first outdoor heat exchanger, 21 is a control valve, and 7 is a second outdoor heat exchanger, which are sequentially connected in a ring to form a refrigeration cycle. The size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. Here, what is different from the fourth embodiment is the structure of the control valve 21.

FIG. 18 is a sectional view of the control valve 21.

In FIG. 18, 10 is a valve element, 11 is a slidable valve seat, 12 is a first bias spring, 13 is a first shape memory alloy spring, 14 is a first flow path, and 15 is a second bias spring. , 16 is a second shape memory alloy spring, 17 is a stopper for stopping the movement of the valve body 10, and 20 is a second flow path.

Temperature-strain curve (hysteresis curve) of the first shape memory alloy spring 13 and the second shape memory alloy spring 16.
Is the same as FIG. 11 of the third embodiment.

The operation of the control valve 21 in the above structure will be described.

The first shape memory alloy spring 13 expands when the temperature exceeds the set transformation temperature T1, pushes the valve body 10 against the spring force of the first bias spring 12, and opens the first flow path 14. Become. On the other hand, when the first shape memory alloy spring 13 becomes lower than the set transformation temperature T2, the valve body 10 pushed by the first bias spring 12 hits the valve seat 11, and the first flow passage 14 is closed. Therefore, the refrigerant can flow only in the second flow path 20 and the flow path is narrowed, so that the pressure is reduced and the temperature of the refrigerant is lowered.

When the temperature of the second shape memory alloy spring 16 becomes lower than the set transformation temperature T4, the spring force of the second bias spring 15 cannot be resisted and the second shape memory alloy spring 16 contracts. The valve seat 11 is pushed by the second bias spring 15, but the valve body 10 is stopped by the stopper 17, so that the moving distance of the valve seat 11 becomes longer than the moving distance of the valve body 10. If the forces of the bias spring 12, the first shape memory alloy spring 13, the second bias spring 15, and the second shape memory alloy spring 16 are adjusted, the first flow path 14 is opened.

Next, the operation of the control valve 21 during operation of the refrigeration system will be described.

During the heating operation, the outdoor temperature is high and the control valve 21
When the temperature of the refrigerant flowing through is higher than the set transformation temperature T2,
As shown in FIG. 18, the first shape memory alloy spring 13 pushes the valve body 10 against the spring force of the first bias spring 12 to compress the first bias spring 12, and the second shape memory alloy spring 16 moves to the first shape memory alloy spring 16. Since the valve seat 11 is pushed against the spring force of the 2 bias spring 15 to compress the 2nd bias spring 15, the 1st flow path 14 will be in an open state, the refrigerant will not be decompressed, and the refrigerant will flow before and after the control valve 21. There is no difference in temperature.

However, when the outdoor air temperature becomes low, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as evaporators become lower than the outdoor air temperature, and the heat is absorbed from the atmosphere, but the non-azeotropic mixed refrigerant. With the use of, due to its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C or higher, the inlet of the first outdoor heat exchanger 5 is lowered to 0 ° C or lower and Frost starts only at the entrance of the outdoor heat exchanger 5. When the temperature of the refrigerant flowing through the control valve 21 is lower than the set transformation temperature T2 of the first shape memory alloy spring 13 and higher than the set transformation temperature T4 of the second shape memory alloy spring 16, the first shape memory is set as shown in FIG. The alloy spring 13 is pushed by the first bias spring 12 to push the valve body 10 against the valve seat 11, and the second shape memory alloy spring 16 pushes the valve seat 11 against the spring force of the second bias spring 15. Since the 2 bias spring 15 is compressed, the first flow path 14 is closed. As a result, the refrigerant can flow only in the second flow passage 20 and the flow passage is narrowed, so that a pressure difference occurs before and after the control valve 21. At this time, the size of the second outdoor heat exchanger 7 is the first
Since it is larger than the outdoor heat exchanger 5, the refrigerant pressure of the second outdoor heat exchanger 7 does not change so much, the refrigerant pressure of the first outdoor heat exchanger 5 rises, and the inlet refrigerant temperature of the first outdoor heat exchanger 5 increases. Also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not thaw and grow.

Further, when the temperature of the refrigerant in the control valve 21 becomes lower than the set transformation temperature T4 of the second shape memory alloy spring 16, frost is grown on the entire first and second outdoor heat exchangers 5, 7. Therefore, as shown in FIG. 20, the second shape memory alloy spring 16 cannot withstand the spring force of the second bias spring 15 and contracts, and the valve seat 11 is pushed by the second bias spring 15. Since the valve body 10 is stopped by the stopper 17, the first flow path 14 is opened. Since the refrigerant is not depressurized, there is no difference in refrigerant temperature before and after the control valve 21. In this way, since there is no pressure difference before and after the control valve 21, it is possible to effectively utilize the first and second outdoor heat exchangers 5 and 7 and enable efficient heating operation.

Further, the temperature of the control valve 21 is low and is pushed by the first and second bias springs 12 and 15 as shown in FIG.
From the state where the first and second shape memory alloy springs 13 and 16 are transformed and contracted, and the control valve 21 is open, the temperature of the refrigerant flowing through the control valve 21 rises due to an increase in the outdoor air temperature,
The temperature becomes higher than the set transformation temperature T3 of the second shape memory alloy spring 16, so that the first and second outdoor heat exchangers 5 and 7 are not frosted entirely, but only the inlet of the first outdoor heat exchanger 5 is frosted. In this state, as shown in FIG. 19, the second shape memory alloy spring 16
Transforms and expands, compresses the second bias spring 15 and presses the valve seat 11 against the valve body 10, so that the first flow path 14 is closed. As a result, the refrigerant can flow only in the second flow path 20 and the flow path is narrowed, so that a pressure difference occurs before and after the control valve 21, the refrigerant pressure in the first outdoor heat exchanger 5 rises, and the first outdoor heat exchanger 5 increases. The refrigerant temperature at the inlet of the heat exchanger 5 also rises. Therefore, the first
Frost at the inlet of the outdoor heat exchanger 5 does not melt and grow.

Further, the temperature of the refrigerant flowing through the control valve 21 is set to the set transformation temperature T1 of the first shape memory alloy spring 13 in a state where the outdoor air temperature rises and frost does not occur on the first outdoor heat exchanger 5. When the temperature becomes higher, the first shape memory alloy spring 13 transforms and expands, compresses the first bias spring 12 to separate the valve body 10 from the valve seat 11, and the first flow path 14 is opened, as shown in FIG. Since the refrigerant is not depressurized, there is no difference in refrigerant temperature before and after the control valve 21.

In this way, partial frosting of the outdoor heat exchanger is prevented, and in a state where frost is formed on the entire outdoor heat exchanger, the control valve 21 is opened to enable efficient heating operation.

[0073]

As is apparent from the above embodiment, according to the inventions of claims 1, 5, and 6, a control valve is provided between the first outdoor heat exchanger and the second outdoor heat exchanger. By providing the second throttle device and the valve control device in parallel with the control valve,
When the control valve operates under a temperature condition in which the first outdoor heat exchanger causes frost formation, the refrigerant flows to the second expansion device, and a differential pressure is generated between the refrigerant before and after the second expansion device, and the first outdoor Since the pressure of the heat exchanger is higher than the pressure of the second outdoor heat exchanger and the temperature of the refrigerant flowing through the first outdoor heat exchanger is high,
Frost formation at the inlet of the first heat exchanger can be prevented, and efficient heating operation can be performed.

According to the second, third and fourth aspects of the present invention, a pressure reducing mechanism is provided between the first outdoor heat exchanger and the second outdoor heat exchanger and a shape memory alloy spring is built in. By providing such a control valve, the shape memory alloy spring transforms under the condition that the outdoor heat exchanger causes frosting and is bent by the bias spring to bend and press the valve body against the valve seat to narrow the refrigerant flow path. Then, a differential pressure occurs between the refrigerant before and after the control valve, the pressure of the first outdoor heat exchanger becomes higher than the pressure of the second outdoor heat exchanger, and the temperature of the refrigerant flowing through the first outdoor heat exchanger becomes high. Therefore, it is possible to prevent frost formation on the first heat exchanger, enable efficient heating operation, and eliminate the need for another expansion device.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of a refrigeration system showing an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a valve control device for a refrigeration system showing an embodiment of the present invention.

FIG. 3 is a block diagram of a valve control device of a refrigeration system showing an embodiment of the present invention.

FIG. 4 is a flowchart of a valve control device of a refrigeration system showing an embodiment of the present invention.

FIG. 5 is a refrigeration cycle diagram of a refrigeration system showing another embodiment of the present invention.

FIG. 6 is a sectional view of a control valve used in another refrigeration system of the present invention.

FIG. 7 is a temperature-strain curve diagram of a shape memory alloy spring of a control valve used in another refrigeration system of the present invention.

FIG. 8 is a sectional view showing the operation of a control valve used in another refrigeration system of the present invention.

FIG. 9 is a refrigeration cycle diagram of a refrigeration system showing another embodiment of the present invention.

FIG. 10 is a sectional view of a control valve used in a refrigeration system showing another embodiment of the present invention.

FIG. 11 is a temperature-strain curve diagram of a shape memory alloy spring of a control valve used in a refrigeration system showing another embodiment of the present invention.

FIG. 12 is a cross-sectional view showing the operation of a control valve used in a refrigeration system showing another embodiment of the present invention.

FIG. 13 is a cross-sectional view showing the operation of a control valve used in a refrigeration system showing another embodiment of the present invention.

FIG. 14 is a refrigeration cycle diagram of a refrigeration system showing still another embodiment of the present invention.

FIG. 15 is a sectional view of a control valve used in a refrigeration system showing still another embodiment of the present invention.

FIG. 16 is a sectional view showing the operation of a control valve used in a refrigeration system showing still another embodiment of the present invention.

FIG. 17 is a refrigerating cycle diagram of a refrigerating apparatus showing still another embodiment of the present invention.

FIG. 18 is a sectional view of a control valve used in a refrigeration system showing still another embodiment of the present invention.

FIG. 19 is a sectional view showing the operation of the control valve used in the refrigeration system showing still another embodiment of the present invention.

FIG. 20 is a cross-sectional view showing the operation of the control valve used in the refrigeration system showing still another embodiment of the present invention.

FIG. 21 is a refrigeration cycle diagram of a conventional refrigeration system.

[Explanation of symbols]

1 compressor 2 four-way valve 3 Indoor heat exchanger 4 Throttling device 5 First outdoor heat exchanger 6 control valve 7 Second outdoor heat exchanger 8 Second diaphragm device 9 control valve 10 valve body 11 seat 12 Bias spring 13 1st shape memory alloy spring 14 First flow path 15 Second bias spring 16 Second shape memory alloy spring 17 Stopper 18 Control valve 19 Control valve 20 Second channel 21 Control valve 22 valve controller 23 Power switch 24 Refrigerant temperature detector 25 A / D converter 26 Microcomputer (LSI) 27 Input circuit 28 CPU 29 memory 30 output circuit 31 electromagnetic coil

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinji Watanabe             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hironao Numamoto             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Yukio Watanabe             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Haneda Kanji             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Yoshinori Kobayashi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Yuichi Yakumaru             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Yamaguchi Adult             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (6)

[Claims] 1. A compressor, a four-way valve, an indoor heat exchanger, a throttle device, a first outdoor heat exchanger, a control valve, and a second outdoor heat exchanger are annularly connected using a non-azeotropic mixed refrigerant, and A refrigerating apparatus, wherein the size of the second outdoor heat exchanger is larger than that of the first outdoor heat exchanger, and a second expansion device is provided in parallel with the control valve. 2. A refrigeration system in which a compressor, a four-way valve, an indoor heat exchanger, a throttle device, a first outdoor heat exchanger, a control valve, and a second outdoor heat exchanger are annularly connected using a non-azeotropic mixed refrigerant. In the refrigeration system, the size of the second outdoor heat exchanger is larger than that of the first outdoor heat exchanger, and the control valve is provided with a pressure reducing mechanism. 3. The control valve comprises a first shape memory alloy spring,
3. The refrigerating apparatus according to claim 1, further comprising a bias spring and a slidable valve element sandwiched between the first shape memory alloy spring and the bias spring. 4. The temperature hysteresis is 2-3 degrees, the transformation temperature during cooling is -2 to -4 ° C., and the transformation temperature during heating is 0 to -2.
The refrigerating apparatus according to claim 3, wherein a first shape memory alloy spring of ℃ is used for the control valve. 5. A first outdoor heat exchanger refrigerant temperature detecting means for detecting and outputting a refrigerant temperature of the first outdoor heat exchanger, and the first outdoor heat exchanger refrigerant temperature and a set temperature are compared, A comparison means for outputting a control signal, a storage means for storing an output mode for controlling the opening and closing of the control valve, and a selection means for selecting one of the output modes of the storage means according to an output signal generated from the comparison means. 3. The refrigerating apparatus according to claim 1, further comprising a valve control device configured by an output unit that opens and closes the control valve according to an output mode of the storage unit. 6. The selecting means opens the control valve when the temperature of the first outdoor heat exchanger is lower than the first set temperature, and controls the control valve when the temperature is higher than the first set temperature and lower than the second set temperature. The refrigerating apparatus according to claim 5, wherein the valve is closed and the control valve is opened when the temperature is higher than the third preset temperature.