JP2948105B2 - Refrigeration air conditioner using non-azeotropic mixed refrigerant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration and air-conditioning system which operates with high operating efficiency and high reliability even when the refrigerant circulation composition is different from the initial filling composition. The present invention relates to a refrigeration air conditioner using a non-azeotropic mixed refrigerant composed of components.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a configuration diagram showing a configuration of a conventional refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant, in which reference numeral 1 denotes a compressor, 2 denotes a condenser, 3 denotes a decompression device, and 4 denotes an evaporator. Numerals 5 and 5 denote accumulators, which are connected in series by piping to form a refrigerating air conditioner, and use a non-azeotropic mixed refrigerant composed of a high-boiling component and a low-boiling component as a refrigerant.

Next, the operation will be described. In the refrigeration and air-conditioning apparatus configured as described above, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 is condensed and liquefied by the condenser 2 and decompressed by the decompression device 3 to become a low-pressure gas-liquid two-phase refrigerant. It flows into the evaporator 4. This refrigerant evaporates in the evaporator 4, returns to the compressor 1 via the accumulator 5, is compressed again, and is sent to the condenser 2. Further, the accumulator 5 prevents the liquid from returning to the compressor 1 by storing excess refrigerant generated by operating conditions and load conditions of the refrigerating air conditioner.

[0004] In such a refrigeration / air-conditioning system, a non-azeotropic mixed refrigerant is used as a refrigerant.
It is conventionally known that advantages such as a lower evaporation temperature or a higher condensation temperature that could not be obtained with a single refrigerant or a higher cycle efficiency can be obtained. . In addition, since refrigerants such as R12 and R22, which have been widely used in the past, cause depletion of the ozone layer, non-azeotropic mixed refrigerants have been proposed as substitutes for these refrigerants.

[0005]

The conventional refrigeration / air-conditioning system using a non-azeotropic refrigerant mixture is constructed as described above. Therefore, if the operating conditions and load conditions of the refrigeration / air-conditioning system are constant, the refrigeration cycle The composition of the refrigerant circulating inside is constant,
An efficient refrigeration cycle as described above is configured. However, when operating conditions and load conditions change, especially when the amount of refrigerant stored in the accumulator changes, the composition of the refrigerant circulating in the refrigeration cycle changes, and control of the refrigeration cycle according to the circulating refrigerant composition, that is, the compressor It is necessary to adjust the flow rate of the refrigerant by controlling the number of rotations and controlling the opening of the expansion valve. However, in the conventional refrigeration / air-conditioning apparatus, since there is no means for detecting the circulating refrigerant composition, there has been a problem that an optimal operation according to the circulating refrigerant composition cannot be maintained. Also, even if the circulating refrigerant composition changes due to a refrigerant leak during use of the refrigeration cycle or a malfunction at the time of charging the refrigerant, the abnormality of the circulating refrigerant composition cannot be detected. There was a problem that it could not be obtained.

The invention of claim 1 has been made in order to solve the above-mentioned problems. Signals from a temperature detector and a pressure detector are calculated by a composition calculator to determine the operating conditions of the refrigeration and air conditioning system. Even if the circulating composition changes due to a change in load conditions, or if the circulating composition changes due to a refrigerant leak during use of a refrigeration / air-conditioning system or a malfunction during charging of the refrigerant, the circulating composition in the cycle can be accurately detected. It is an object of the present invention to obtain a refrigeration air conditioner using a non-azeotropic mixed refrigerant that can be used.

According to a second aspect of the present invention, the signals from the first and second temperature detectors and the pressure detectors are calculated by a composition calculator, and the circulating composition changes due to changes in the operating conditions and load conditions of the refrigeration and air conditioning system. Even if the refrigerant composition leaks during use of the refrigeration / air-conditioning system, or if the circulating composition changes due to a malfunction during the charging of the refrigerant, a non-azeotropic mixed refrigerant that can accurately detect the circulating composition in the cycle is used. The purpose is to obtain a refrigeration air conditioner.

According to a third aspect of the present invention, signals from a plurality of temperature detectors and pressure detectors are calculated by a composition calculator, and when the circulating composition changes due to a change in operating conditions or load conditions of the refrigeration and air conditioning system, Alternatively, a refrigeration air conditioner using a non-azeotropic mixed refrigerant that can accurately detect the circulating composition in the cycle even if the circulating composition changes due to refrigerant leakage during use of the refrigeration air conditioning device or malfunction during refrigerant charging. The purpose is to gain.

A fourth object of the present invention is to obtain a refrigeration and air-conditioning apparatus using a non-azeotropic mixed refrigerant, which is made compact by exchanging heat between the high-pressure side and the low-pressure side of the bypass pipe. .

According to a fifth aspect of the present invention, a signal from a plurality of temperature detectors for detecting the temperature and pressure of the low-pressure side refrigerant and a signal from the pressure detector are calculated by a composition calculator, and operating conditions and load conditions of the refrigeration and air-conditioning apparatus are calculated. The circulating composition in the cycle can be accurately detected even if the circulating composition changes due to a change in the circulating composition, or if the circulating composition changes due to a refrigerant leak during use of the refrigeration / air-conditioning device or a malfunction during the charging of the refrigerant. It is an object of the present invention to obtain a refrigeration air conditioner using an azeotropic mixed refrigerant.

According to a sixth aspect of the present invention, there is provided a control device for controlling a compressor, a first decompression device, and the like in accordance with the refrigerant composition detected by the composition computing device. A non-azeotropic mixed refrigerant that enables optimal operation of the refrigeration air conditioner even when the circulation composition changes, or when the refrigerant composition changes due to refrigerant leakage during use of the refrigeration air conditioner or a malfunction during filling of the refrigerant. The purpose is to obtain a refrigeration air conditioner.

According to a seventh aspect of the present invention, there is provided a comparison operation means for issuing a warning signal when the circulating composition is out of a predetermined range,
It is possible to reliably detect that the circulating composition of a non-azeotropic mixed refrigerant changes due to refrigerant leakage during use, or that the circulating composition has changed due to a malfunction during refrigerant charging. The purpose is to obtain the used refrigeration and air-conditioning system.

[0013]

According to a first aspect of the present invention, there is provided a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant, comprising: a temperature detector for detecting a temperature and a pressure of a low-pressure side refrigerant; a pressure detector; And a composition calculator for calculating the composition of the refrigerant circulating in the refrigeration cycle from the signal detected by the pressure detector and the pressure detector.

According to a second aspect of the present invention, there is provided a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant, comprising: a first temperature detector for detecting the temperature and pressure of the low-pressure refrigerant; a pressure detector; A second temperature detector for detecting, and a composition calculator for calculating a refrigerant composition circulating in the refrigeration cycle from signals detected by the first temperature detector, the second temperature detector, and the pressure detector. is there.

According to a third aspect of the present invention, there is provided a refrigeration / air-conditioning system using a non-azeotropic refrigerant mixture, wherein three or more temperature detectors for detecting the temperature of the high-pressure refrigerant and a pressure detector for detecting the pressure of the high-pressure refrigerant. And a composition calculator for calculating the composition of the refrigerant circulating in the refrigeration cycle from signals detected by three or more temperature detectors and pressure detectors.

A refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant according to the invention of claim 4 is configured such that heat is exchanged between a high pressure side and a low pressure side as a method of cooling a bypass pipe.

According to a fifth aspect of the present invention, there is provided a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant, comprising three or more temperature detectors for detecting the temperature of the low-pressure refrigerant and a pressure detector for detecting the pressure of the low-pressure refrigerant. And a composition calculator for calculating the composition of the refrigerant circulating in the refrigeration cycle from signals detected by three or more temperature detectors and pressure detectors.

A refrigeration and air-conditioning system using a non-azeotropic mixed refrigerant according to the invention of claim 6 is provided with a control device for controlling a compressor, a first pressure reducing device, and the like according to the refrigerant composition detected by a composition calculator. It is a thing.

According to a seventh aspect of the present invention, there is provided a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant, comprising: a comparison operation means for issuing a warning signal when the refrigerant composition detected by the composition operation device is out of a predetermined range; And an alarm device operated by the alarm signal generated by the comparison operation means.

[0020]

According to the first aspect of the present invention, a refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant calculates a refrigerant composition circulating in a refrigeration cycle from signals detected by a temperature detector and a pressure detector. Even if the circulating composition changes due to changes in operating conditions or load conditions, or if the circulating composition changes due to a refrigerant leak during use of a refrigeration / air-conditioning system or a malfunction during charging of the refrigerant, the circulating composition in the cycle can be accurately determined. Detect.

A refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant according to the second aspect of the present invention provides a refrigerant circulating in a refrigeration cycle based on signals detected by a first temperature detector, a second temperature detector and a pressure detector. Calculate the composition, if the circulating composition changes due to changes in the operating conditions and load conditions of the refrigeration and air conditioning system,
Alternatively, even if the circulating composition changes due to a refrigerant leak during use of the refrigeration / air-conditioning apparatus or a malfunction at the time of charging the refrigerant, the circulating composition in the cycle is accurately detected.

The refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant according to the third aspect of the present invention provides a refrigeration cycle based on signals detected by a plurality of temperature detectors for detecting the temperature of the high-pressure side refrigerant and the pressure detectors. Calculate the circulating refrigerant composition, when the circulating composition changes due to changes in the operating conditions and load conditions of the refrigeration air conditioner, or refrigerant leakage during use of the refrigeration air conditioner,
Even if the circulating composition changes due to a malfunction at the time of charging the refrigerant, the circulating composition in the cycle is accurately detected.

In the refrigeration / air-conditioning system using the non-azeotropic refrigerant mixture according to the fourth aspect of the present invention, heat is exchanged between the high-pressure side and the low-pressure side as a method of cooling the bypass pipe, thereby making the structure of the refrigeration / air-conditioning system compact. can do.

According to a fifth aspect of the present invention, there is provided a refrigeration / air-conditioning apparatus using a non-azeotropic refrigerant mixture, wherein a plurality of temperature detectors for detecting the temperature of the low-pressure side refrigerant and signals detected by the pressure detectors are used to control the inside of the refrigeration cycle. Calculate the circulating refrigerant composition, when the circulating composition changes due to changes in the operating conditions and load conditions of the refrigeration air conditioner, or refrigerant leakage during use of the refrigeration air conditioner,
Even if the circulating composition changes due to a malfunction at the time of charging the refrigerant, the circulating composition in the cycle is accurately detected.

According to the sixth aspect of the present invention, a refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant controls a compressor, a first pressure reducing device, and the like in accordance with a refrigerant composition detected by a composition calculator, and Optimum operation of the refrigeration air conditioner is possible even when the circulation composition changes due to changes in operating conditions and load conditions, or when the refrigerant composition changes due to refrigerant leakage during use of the refrigeration air conditioner or malfunction during filling of the refrigerant. .

In the refrigeration and air-conditioning system using the non-azeotropic mixed refrigerant according to the seventh aspect of the present invention, when the circulating composition is out of a predetermined range, an alarm is activated by a warning signal, and the circulating composition of the non-azeotropic mixed refrigerant is reduced. It reliably detects a change due to a refrigerant leak during use or a change in the circulation composition due to a malfunction at the time of charging the refrigerant.

[0027]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a refrigerant circuit diagram showing a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 1 of the present invention. In the drawing, 1 is a compressor, 2 is a condenser, and 3 is, for example, a first capillary. The first decompression device 4 is an evaporator, 4 is an accumulator, and 5 is an accumulator, and these are connected in series by piping to constitute a refrigeration cycle. In this refrigeration cycle, for example, a high boiling component R134a and a low boiling component R32
Is charged.

Reference numeral 11 denotes a bypass pipe which bypasses a discharge pipe of the compressor 1 and a suction pipe of the compressor 1, and a second capillary 12 as a second pressure reducing device is provided in the middle of the bypass pipe 11. . Reference numeral 13 denotes a double-pipe heat exchanger as cooling means for cooling the non-azeotropic refrigerant mixture flowing from the high-pressure side of the bypass pipe 11 into the second capillary tube 12, and is constituted by a heat exchanger with the low-pressure side of the bypass pipe 11. Have been. At the outlet of the second capillary tube 12, a first temperature detector 21 for detecting the refrigerant temperature and a first pressure detector 22 for detecting the refrigerant pressure are provided. Reference numeral 30 denotes a composition calculator to which detection signals of the first temperature detector 21 and the first pressure detector 22 are input.

The composition calculator 30 circulates the non-azeotropic refrigerant mixture in the refrigeration cycle based on the temperature and pressure at the outlet of the second capillary tube 12 detected by the first temperature detector 21 and the first pressure detector 22. It has the function of calculating the composition.

Next, the operation will be described. The high-temperature and high-pressure refrigerant gas compressed in the compressor 1 is condensed and liquefied in the condenser 2,
The pressure is reduced by the first pressure reducing device 3, and the low-pressure gas-liquid two-phase refrigerant flows into the evaporator 4. This refrigerant evaporates in the evaporator 4, returns to the compressor 1 via the accumulator 5, is compressed again, and is sent to the condenser 2. Excess non-azeotropic refrigerant mixture generated due to operating conditions and load conditions of the refrigeration / air-conditioning device accumulates in the accumulator 5. This accumulator 5
The refrigerant therein is separated into a liquid phase rich in high boiling components and a gas phase rich in low boiling components, and the liquid phase rich in high boiling components is stored in the accumulator 5. For this reason, when the liquid refrigerant exists in the accumulator 5, the refrigerant composition circulating in the refrigeration cycle tends to have a large amount of low-boiling components (the circulation composition increases).

A part of the high-pressure steam refrigerant discharged from the compressor 1 flows into the bypass pipe 11, and the double pipe heat exchanger 1
The heat exchanges with the low-pressure refrigerant in the annular portion 3 to condense and liquefy.
This liquid refrigerant is decompressed in the second capillary tube 12, becomes a low-pressure refrigerant, flows into the inner tube of the double-tube heat exchanger 13, exchanges heat with the high-pressure refrigerant in the annular portion, and evaporates. This low-pressure vapor refrigerant flows into the suction pipe of the compressor 1. FIG. 2 shows a change in the state of the refrigerant in the bypass pipe 11 on a pressure-enthalpy diagram, in which point A is the inlet on the high pressure side of the double tube heat exchanger 13 and point B is the double The high pressure side outlet of the tube heat exchanger 13 and the inlet of the second capillary 12, the point C is the low pressure side inlet of the double tube heat exchanger 13 and the outlet of the second capillary 12, and the point D is the double tube heat exchanger 13. This shows the state of the non-azeotropic mixed refrigerant at the low pressure side outlet.

The double tube heat exchanger 13 is designed so that sufficient heat exchange is performed between the high-pressure refrigerant and the low-pressure refrigerant.
Further, as shown by the dashed line in FIG. 2, the isotherm is substantially vertical in the liquid phase region, so the refrigerant temperature at the high pressure side outlet of the double tube heat exchanger 13 represented by the point B is represented by the point C. Is cooled to the vicinity of the low-pressure-side inlet refrigerant temperature of the double-tube heat exchanger 13. Further, since the refrigerant passing through the second capillary 12 undergoes isenthalpy expansion, the double-tube heat exchanger 13 represented by point B
The low-pressure-side inlet refrigerant is in a substantially low-pressure saturated liquid state.

Next, the operation of the composition calculator 30 will be described with reference to the vapor-liquid equilibrium diagram of the non-azeotropic mixed refrigerant in FIG. The composition calculator 30 takes in the temperature (T1) and the pressure (P1) at the outlet of the second capillary 12 in the low-pressure saturated liquid state from the first temperature detector 21 and the first pressure detector 22. Pressure P1
The saturated liquid temperature of the non-azeotropic refrigerant mixture changes in accordance with the circulation composition in the refrigeration cycle, that is, the circulation composition flowing in the bypass pipe 11, as shown in FIG. Here, the circulation composition is the weight fraction of the low boiling point component of the non-azeotropic mixed refrigerant.
Therefore, by using the relationship of FIG. 3, the circulation composition α in the cycle can be detected from the temperature T1 and the pressure P1 detected by the first temperature detector 21 and the first pressure detector 22. FIG. 4 shows the relationship between the saturated liquid temperature T1, the pressure P1, and the circulation composition α from the vapor-liquid equilibrium diagram of the non-azeotropic refrigerant mixture shown in FIG. This relationship is determined in advance by the composition calculator 3
If stored in 0, the circulation composition α can be calculated from the temperature T1 and the pressure P1. 4 is, for example, α = (a · T1 ² + b · T1 + c) (d · P1 ² + e ·
P1 + f) Here, a, b, c, d, e, and f are represented by constants, and based on this equation, the composition calculator 30 calculates
The circulation composition α is calculated.

Although the above-described circulating composition detection method has been described for the case where the refrigerant at the low-pressure side of the double-tube heat exchanger 13 is in a saturated liquid state, the heat exchange in the double-tube heat exchanger 13 is not sufficient. Rather, even if the low-pressure side inlet refrigerant of the double tube heat exchanger 13 does not reach the saturated liquid state and slightly enters the gas-liquid two-phase state,
The detection accuracy of the circulation composition is sufficiently ensured. This is shown in FIG.
This is because, for example, in the non-azeotropic mixed refrigerant composed of R32 and R134a, the change in the equilibrium temperature with respect to the change in dryness in the gas-liquid two-phase state is small. FIG. 5 shows a pressure of 500k.
The weight fraction of R32 and R134a in Pa was 2
It is a graph showing a change in equilibrium temperature with respect to a change in dryness X in a gas-liquid two-phase state of a non-azeotropic mixed refrigerant mixed at 5% and 75%. In R32 / R134a, the difference between the saturated liquid temperature (the temperature at X = 0) and the saturated vapor temperature (the temperature at X = 1) is as small as about 6 ° C., so that the equilibrium temperature and the saturated liquid temperature at X = 0.1 Is as small as about 0.8 ° C. Therefore, in the circulation composition detection method of the present embodiment, even if the low pressure side inlet refrigerant of the double pipe heat exchanger 13 is in a gas-liquid two-phase state with a dryness of about 0.1, the temperature difference from the saturated liquid state is Very small,
The detection accuracy of the circulating composition is sufficiently secured for practical use.

In the present embodiment, the case where the double-tube heat exchanger 13 for the low-pressure side refrigerant is used as the cooling means for the high-pressure side refrigerant has been described. The same effect can be obtained by performing heat exchange.

In this embodiment, a two-component refrigerant is described as a mixed refrigerant. However, similar effects can be obtained in the case of a multi-component refrigerant such as a three-component refrigerant.

Embodiment 2 FIG. FIG. 6 is a refrigerant circuit diagram showing a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 2 of the present invention. In the drawing, an electric expansion valve 120 is used as a second pressure reducing means. The electric expansion valve 12
A second temperature detector 24 for detecting the temperature of the refrigerant is provided at the inlet of the zero. The composition calculator 30 detects the electric expansion valve 1 based on the temperature and pressure detected by the first temperature detector 21, the first pressure detector 22, and the second temperature detector 24.
It has a function of calculating the dryness of the refrigerant at the outlet 20 and the circulating composition of the non-azeotropic mixed refrigerant in the refrigeration cycle. Reference numeral 31 denotes an electric expansion valve controller, which detects the temperature at the outlet of the electric expansion valve 120 detected by the first temperature detector 21 and the low-pressure side of the double-pipe heat exchanger 13 detected by the second temperature detector 24. It has a function of controlling the opening of the electric expansion valve 120 based on the temperature of the outlet.

Next, the operation will be described. A part of the high-pressure vapor refrigerant discharged from the compressor 1 flows into the bypass pipe 11, and exchanges heat with the low-pressure refrigerant in the annular portion of the double pipe heat exchanger 13 to condense and liquefy. This liquid refrigerant is decompressed by the electric expansion valve 120, becomes a low-pressure gas-liquid two-phase refrigerant having a dryness of X, flows into the inner pipe portion of the double-tube heat exchanger 13, and exchanges heat with the high-pressure refrigerant in the annular portion. Change and evaporate. This low-pressure vapor refrigerant flows into the suction pipe of the compressor 1. FIG. 7 shows a change in the state of the refrigerant in the bypass pipe 11 on a pressure-enthalpy diagram. In FIG. 7, point A is the inlet on the high pressure side of the double tube heat exchanger 13 and point B is the double The high pressure side outlet of the pipe heat exchanger 13 and the inlet of the electric expansion valve 120, point C is the low pressure side inlet of the double pipe heat exchanger 13 and the outlet of the electric expansion valve 120, and the point D is the double pipe heat exchanger. 13 illustrates the state of the non-azeotropic mixed refrigerant at the low pressure side outlet of No. 13. The double tube heat exchanger 13
Sufficient heat exchange is performed between the high-pressure refrigerant and the low-pressure refrigerant, and the refrigerant at the high-pressure outlet of the double-pipe heat exchanger 13 and the inlet of the electric expansion valve 120 represented by point B is in a supercooled state. It is designed to be.

The operation of the composition calculator 30 will be described with reference to the flowchart shown in FIG. When the operation of the composition calculator 30 is started, first, the refrigerant temperature T1 at the outlet of the electric expansion valve 120 detected by the first temperature detector 21, the first pressure detector 22, and the second temperature detector 24 is detected. And the pressure P1 and the refrigerant temperature T2 at the inlet of the electric expansion valve 120,
0 (step ST1). Next, a circulation composition α in the refrigeration cycle is assumed (step ST2). This assumed value α of the circulation composition and the inlet temperature T2 of the electric expansion valve 120
From the outlet pressure P1 of the electric expansion valve 120, the dryness X of the refrigerant at the outlet of the electric expansion valve 120 is calculated (step ST3). That is, since the refrigerant passing through the electric expansion valve 120 expands with isentropy, the inlet temperature T2 of the electric expansion valve 120, the outlet pressure P1 of the electric expansion valve 120, and the dryness X are as shown in FIG. There is a relationship as shown. Therefore, if this relation is stored in advance in the composition calculator 30 as the relational expression of X = f ₁ (T2, P1, α) (1), this equation (1) can be used. From the temperature T2, pressure P1, and assumed circulation composition value α, the dryness X of the refrigerant at the outlet of the electric expansion valve 120
Can be calculated. Further, the electric expansion valve 120
The circulation composition α ′ is calculated from the outlet temperature T1, the pressure P1, and the dryness X obtained in step ST3 (step S3).
T4). That is, the temperature of the non-azeotropic mixed refrigerant in the gas-liquid two-phase state with the dryness X at the pressure P1 changes as shown in FIG. 10 depending on the circulation composition in the refrigeration cycle, that is, the circulation composition flowing in the bypass pipe 11. Therefore, by using the relationship of FIG. 10, the circulation composition α ′ in the cycle can be calculated from the temperature T1, the pressure P1, and the dryness X at the outlet of the electric expansion valve 120. FIG.
From the relationship of 0, the relationship between the temperature T1 and the pressure P1 at the outlet of the electric expansion valve 120 and the dryness X and the circulation composition α is shown. Therefore, if this relation is stored in advance in the composition calculator 30 as a relational expression of α ′ = f ₂ (T1, P1, X) (2), this expression (2) is obtained. The circulating composition α ′ can be calculated from the temperature T2, the pressure P1, and the dryness X at the outlet of the electric expansion valve 120 using the above method. The circulating composition α ′ is compared with the initially assumed circulating composition α, and if they match, the circulating composition is obtained as α (step ST5). If they do not match, the circulation composition α is assumed again (step ST6), and the process returns to step ST3 to perform the above calculation, and continues the calculation until the two match.

Next, the operation of the electric expansion valve controller 31 will be described. The electric expansion valve controller 31 controls the opening of the electric expansion valve 120 so that the refrigerant at the high pressure side outlet of the double-pipe heat exchanger 13 is surely in a supercooled state. That is, the electric expansion valve controller 31 determines the temperature (T1) of the outlet of the electric expansion valve 120 detected by the first temperature detector 21 and the inlet of the electric expansion valve 120 detected by the second temperature detector 24. Part temperature (T2), the difference temperature (T2-T
Calculate 1). Further, the electric expansion valve controller 31 sets the P differential so that the temperature difference becomes equal to or less than a predetermined value (for example, 10 ° C.).
Electric expansion valve 1 by feedback control such as ID control
Calculates the opening correction value of 20 and sends the opening command to the electric expansion valve 1
20. As a result, the refrigerant at the high pressure side outlet of the double tube heat exchanger 13 is reliably in a supercooled state, and the flow rate of the refrigerant flowing through the bypass pipe 11 can be minimized to minimize the energy loss of the refrigeration cycle.

Since the composition calculator 30 of this embodiment calculates the dryness of the refrigerant at the outlet of the electric expansion valve 120 to calculate the circulation composition, the operating state of the refrigeration cycle changes.
Even if the amount of heat exchange of the double tube heat exchanger 13 changes, the circulation composition can be reliably detected. Also, bypass pipe 11
Is controlled by the electric expansion valve 120 to ensure that the refrigerant at the high pressure side outlet of the double-tube heat exchanger 13 is in a supercooled state. In addition, the flow rate of the refrigerant flowing through the bypass pipe 11 can be minimized to minimize the energy loss of the refrigeration cycle.

Embodiment 3 FIG. FIG. 12 is a refrigerant circuit diagram illustrating a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 3 of the present invention. In FIG. 12, a heat pump type refrigeration / air-conditioning apparatus capable of performing cooling and heating by switching a four-way valve 51. Is shown. 52 is an outdoor heat exchanger that operates as a condenser during cooling and as an evaporator during heating, and 61 is an indoor heat exchanger that operates as an evaporator during cooling and as a condenser during heating. The configurations of the bypass pipe 11, the composition calculator 30, the electric expansion valve controller 31, and the like are the same as those in the second embodiment.

The principle of detecting the circulating composition shown in Example 2 is as follows.
This is also established by using the outlet temperature, the pressure, and the inlet temperature of the first pressure reducing device 3 in the main circuit. However, since the flow direction of the refrigerant in the first pressure reducing device 3 is different between cooling and heating, the circulation composition during cooling and heating is reduced. For detection, a temperature detector and a pressure detector are required at the entrance and exit of the first decompression device 3, respectively, and it is necessary to provide a total of four detectors. However, in the refrigerating air conditioner of this embodiment, the first temperature detector 21, the first pressure detector 22, and the second temperature detector 24 in the bypass pipe 11 always use the three detectors regardless of cooling or heating. , The circulating composition can be detected. That is, in the present embodiment, the number of detectors is small, and the circulating composition during cooling and heating can be detected at low cost.

Embodiment 4 FIG. FIG. 13 is a refrigerant circuit diagram showing a refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant according to Embodiment 4 of the present invention.
2 is used. The operation of the composition calculator 30 is the same as that of the first embodiment, and the description is omitted. However, by using a cheaper capillary tube than the electric expansion valve as the second pressure reducing device, non-azeotropic mixing can be performed at low cost. The circulating composition of the refrigerant can be detected.

Embodiment 5 FIG. FIG. 14 is a refrigerant circuit diagram showing a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 5 of the present invention. In the drawing, as a double-pipe heat exchanger 13 for cooling high-pressure refrigerant in a bypass pipe 11, It shows one that exchanges heat with the surrounding air. The refrigerant vapor guided to the bypass pipe 11 exchanges heat with the surrounding air in the double pipe heat exchanger 13 to be condensed and liquefied. This liquid refrigerant is decompressed by the capillary tube 12, becomes a low-pressure refrigerant, and flows into the accumulator 5. In this double-pipe heat exchanger 13, fins 14 are provided on the surface of the pipe through which the high-pressure refrigerant flows inside the pipe to promote heat exchange with ambient air. The operation of the composition calculator 30 is the same as that of the second embodiment, and the description is omitted. However, by using an inexpensive finned tube as the cooling means, it is possible to detect the circulating composition of the non-azeotropic refrigerant mixture at low cost. Can be.

Embodiment 6 FIG. FIG. 15 is a refrigerant circuit diagram showing a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 6 of the present invention. In the drawing, the high-pressure side pipe of the double-tube heat exchanger 13 has Five temperature detectors 25a, 2
5 b, 25 c, 25 d, and 25 e are provided, and a pressure detector 26 for measuring a high pressure of the bypass pipe 11 is attached to an inlet of the bypass pipe 11. The composition calculator 30 has a function of calculating the circulating composition of the non-azeotropic mixed refrigerant in the refrigeration cycle based on the temperatures and pressures detected by the five temperature detectors 25 and the pressure detectors 26. Further, a second capillary tube 12 is used as a second decompression device.

Next, the operation of the composition calculator 30 will be described.
The high-pressure vapor refrigerant that has flowed into the double-tube heat exchanger 13 exchanges heat with a low-temperature low-pressure refrigerant and is condensed and liquefied. FIG. 16 shows the temperature change of the high-pressure refrigerant. The double-tube heat exchanger 13 has a superheated steam region at the high pressure side inlet, a two-phase region at the intermediate portion, and a supercooled liquid region at the outlet. The detected values of the five temperature detectors 25 attached to the high pressure side pipe of the double pipe heat exchanger 13
a, Tb, Tc, Td, and Te are shown in FIG. Since the latent heat changes in the two-phase region, the temperature change is small, and the temperatures Ta, T
Temperature changes of b and Tc also become small. On the other hand, in the supercooled liquid region, sensible heat changes, so the temperature change is large, and the temperature changes of Td and Te that detect the temperature of the supercooled liquid region also become large. Therefore, the difference between the temperature signals of the five temperature detectors 25 is sequentially compared in the flow direction, and the temperature at the point where the difference greatly changes can be regarded as the saturated liquid temperature.
For example, in the example shown in FIG. 16, the temperature difference (T
a-Tb), (Tb-Tc), (Tc-Td), (Td
−Te), (Tc−Td) becomes larger than the values of (Ta−Tb) and (Tb−Tc), and as a result, T
c can be regarded as the saturated liquid temperature.

Further, in the composition calculator 30, from the saturated liquid temperature Tc and the high pressure P detected by the pressure detector 26, the relationship between the saturated liquid temperature, the pressure and the circulation composition shown in FIG.
The circulation composition α is calculated.

Embodiment 7 FIG. FIG. 18 is a refrigerant circuit diagram of a refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant according to Embodiment 7 of the present invention. In the drawing, a double-pipe heat exchanger 13 includes a high-pressure pipe and a low-pressure pipe of a bypass pipe 11. And a heat exchanger in contact with the heat exchanger. Further, a second capillary tube 12 is used as a second decompression device. In the low pressure side pipe of the double pipe heat exchanger 13, five temperature detectors 25a, 25b,
25 c, 25 d, and 25 e are provided, and a pressure detector 27 for measuring a low pressure of the bypass pipe 11 is attached to an outlet of the bypass pipe 11. The composition calculator 30 includes five temperature detectors 25 and a pressure detector 27.
Has the function of calculating the circulating composition of the non-azeotropic refrigerant mixture in the refrigeration cycle based on the temperature and pressure detected by the refrigeration cycle.

Next, the operation of the composition calculator 30 will be described. The high-pressure vapor refrigerant that has flowed into the double-tube heat exchanger 13 exchanges heat with a low-temperature low-pressure refrigerant and is condensed and liquefied. This liquid refrigerant is decompressed by the capillary tube 12, becomes a low-pressure two-phase refrigerant, and flows into the double-tube heat exchanger 13. This low-pressure two-phase refrigerant is heated in the double-pipe heat exchanger 13, becomes superheated vapor refrigerant, and flows into the suction pipe of the compressor 1. FIG. 19 shows the temperature change of the low-pressure refrigerant. The double-tube heat exchanger 13 has a two-phase region at the low-pressure-side inlet and a superheated steam region at the outlet.
The detected values of the five temperature detectors 25 attached to the low-pressure pipe of the double-pipe heat exchanger 13 are represented by Ta, Tb, Tc, Td,
Te is shown in FIG. Since the latent heat changes in the two-phase region, the temperature change is small, and the temperature changes of Ta, Tb, and Tc detecting the temperature in the two-phase region are also small. On the other hand, in the superheated steam region, sensible heat changes,
The temperature change is large, and the temperature changes of Td and Te detecting the temperature of the supercooled liquid region also become large. Therefore, 5
The difference between the temperature signals of the individual temperature detectors 25 is sequentially compared in the flow direction, and the temperature at the point where the difference greatly changes can be regarded as the saturated liquid temperature. For example, in the example shown in FIG. 19, the temperature differences (Ta−Tb), (Tb−T
c), (Tc−Td), and (Td−Te) are compared, and (T
a-Tb) and (Tb-Tc).
d) becomes large, and as a result, Tc can be regarded as a saturated steam temperature.

Further, the composition calculator 30 calculates the circulation composition α from the saturated steam temperature Tc, the low pressure P detected by the pressure detector 27, and the relationship between the saturated steam temperature, the pressure and the circulation composition shown in FIG. I do.

Embodiment 8 FIG. FIG. 21 is a refrigerant circuit diagram of a refrigeration / air-conditioning system using a non-azeotropic mixed refrigerant according to Embodiment 8 of the present invention, and shows a refrigeration / air-conditioning system in which one outdoor unit is connected to two indoor units. I have. In the figure, reference numeral 50 denotes an outdoor unit, which includes a compressor 1, a bypass pipe 11, and an outdoor heat exchanger 5.
2. It is composed of an outdoor blower 53 and an accumulator 5, and a second pressure detector 26 is provided in a pipe on the discharge side of the compressor 1. 60 is an indoor unit, and an indoor heat exchanger 61;
The first pressure reducing device 3 is constituted by a first electric expansion valve,
A fourth temperature detector 6 is provided at the entrance and exit of the indoor heat exchanger 46.
Second, a fifth temperature detector 63 is provided. Also, 11
Is a bypass pipe that bypasses the discharge pipe and the suction pipe of the compressor 1.
A second electric expansion valve 120 as a pressure reducing device is provided. A cooling means 13 cools the non-azeotropic mixed refrigerant flowing from the high pressure side of the bypass pipe 11 to the second electric expansion valve 120, and is constituted by a double-pipe heat exchanger with the low pressure side of the bypass pipe 11. ing. Also, the second electric expansion valve 120
A first temperature detector 21 for detecting the refrigerant temperature
And a first pressure detector 22 for detecting a refrigerant pressure, and a second temperature detector 24 for detecting a refrigerant temperature is provided at an inlet of the second electric expansion valve 120. Note that the indoor blower is omitted.

The composition calculator 30 is configured to control the second electric expansion valve in the bypass pipe 11 based on the temperature and pressure detected by the first temperature detector 21, the first pressure detector 22, and the second temperature detector 24. It has a function of calculating the refrigerant dryness at the outlet 120 and the circulating composition of the non-azeotropic mixed refrigerant in the refrigeration cycle.

Reference numeral 40 denotes a control device, which is a circulating composition signal from the composition calculator 30 and the first temperature detector 21, the third temperature detector 23, the first pressure detector 22, and the second pressure detector 2.
6. Signals from the fourth temperature detector 62 and the fifth temperature detector 63 in the indoor unit 60 are input. The control device 40 determines the rotation speed of the compressor 1 and the rotation speed of the outdoor blower 53 according to the circulating composition from these input signals, the opening degree of the first electric expansion valve that is the first pressure reducing device 3 of the indoor unit 60, and Bypass piping 1
The opening degree of the first second electric expansion valve 120 is calculated, and the command is sent to the compressor 1, the outdoor blower 53, and the first electric expansion valve and the second electric expansion valve 120 which are the first pressure reducing device 3, respectively. Send. The compressor 1, the outdoor blower 53, the first electric expansion valve and the second electric expansion valve 120, which are the first pressure reducing device 3, receive the command value sent from the control device 40, and their rotation speed and valve opening. The degree is set.

Reference numeral 41 denotes a comparison operation unit which receives a circulating composition signal from the composition operation unit 30 and performs a comparison operation to determine whether or not the circulating composition is within a predetermined range. An alarm device 42 is connected to the comparator 41,
When the circulation composition is out of the predetermined range, a warning signal is transmitted to the warning device 42.

Next, the operation of the present embodiment configured as described above will be described with reference to the refrigerant circuit diagram of FIG. 21 and the control block diagram of FIG. The composition calculator 30 is
The signals from the first temperature detector 21, the first pressure detector 22, and the second temperature detector 24 provided in the bypass pipe 11 are taken in, and the second electric expansion valve 120 is provided in the same manner as in the second embodiment.
Is calculated, and the circulation composition α in the refrigeration cycle is calculated. In the control device 40, the optimum rotation speed command of the compressor 1 and the outdoor blower 5
The rotation number command of the third, the opening command of the first electric expansion valve which is the first pressure reducing device 3, and the opening command of the second electric expansion valve 120 are calculated.

First, the heating operation will be described. During the heating operation, the refrigerant circulates in the direction of the solid line arrow in FIG. 21, and the outdoor heat exchanger 52 functions as an evaporator and the indoor heat exchanger 61 functions as a condenser to perform heating. The rotation speed of the compressor 1 is controlled such that the condensing pressure matches the target value, and the target condensing pressure value is obtained as a pressure at which the condensing temperature Tc becomes 50 ° C., for example. If the condensation temperature of the non-azeotropic refrigerant mixture is defined as the average value of the saturated vapor temperature and the saturated liquid temperature, the condensation temperature Tc is 50 ° C.
Is determined uniquely by the circulation composition α, as shown in FIG. Therefore, in the control device 40, if the relationship of FIG. 23 is stored in advance in the control device 40 as a relational expression of Pc = f ₃ (α) (3), this expression (3) is obtained. The condensing pressure target value Pc is calculated from the circulating composition signal α transmitted from the composition calculator 30 using the calculation. Further, in the control device 40, according to the difference between the pressure P2 detected by the second pressure detector 26 and the condensing pressure target value Pc,
A correction value of the rotation speed of the compressor 1 is calculated by feedback control such as PID control, and the compressor rotation speed command is
Is output to

The number of revolutions of the outdoor blower 53 is controlled so that the evaporation pressure matches the target value, and the target evaporation pressure is determined, for example, as the pressure at which the evaporation temperature Te becomes 0 ° C. If the evaporation temperature of the non-azeotropic mixed refrigerant is defined as the average value of the saturated vapor temperature and the saturated liquid temperature, the evaporation pressure target value Pe at which the evaporation temperature Te becomes 0 ° C. is determined by the circulation composition α as shown in FIG. Uniquely determined. Therefore, in the control device 40,
If the relation of FIG. 24 is stored in advance in the control device 40 as a relational expression of Pe = f ₄ (α) (4), the composition calculator 30 can be obtained by using this expression (4). Is calculated from the circulating composition signal α transmitted from. Further, in the control device 40, according to the difference between the pressure P1 detected by the first pressure detector 22 and the evaporation pressure target value Pe,
Outdoor blower 5 by feedback control such as PID control
The corrected value of the rotation speed of 3 is calculated, and the outdoor blower rotation speed command is output to the outdoor blower 53.

The degree of opening of the first electric expansion valve as the first pressure reducing device 3 is determined such that the degree of supercooling at the outlet of the indoor heat exchanger 61 is a predetermined value.
For example, the temperature is controlled to be 5 ° C. This degree of supercooling is
It can be obtained as the difference between the saturated liquid temperature at the pressure in the indoor heat exchanger 61 and the outlet temperature of the indoor heat exchanger 61,
The saturated liquid temperature can be obtained as a function of the pressure and the circulation composition as shown in FIG. Therefore, in the control device 40,
If the relation of FIG. 25 is stored in advance in the control device 40 as a relational expression of Tbub = f ₅ (P2, α) (5), the composition calculation is performed using the expression (5). The saturated liquid temperature Tbu and indoor heat exchange are obtained using the circulating composition signal α transmitted from the heater 30, the pressure signal P2 transmitted from the second pressure detector 26, and the temperature signal T4 transmitted from the fourth temperature detector 62. The degree of supercooling at the outlet of the vessel 61 (Tbu-T4) is calculated. Further, the control device 40 corrects the opening degree of the first electric expansion valve which is the first pressure reducing device 3 by feedback control such as PID control in accordance with the difference between the outlet subcooling degree and a predetermined value (5 ° C.). The value is calculated, and the electric expansion valve opening command is output to the first electric expansion valve which is the first pressure reducing device 3.

The degree of opening of the second electric expansion valve 120 is controlled so that the refrigerant at the outlet on the high pressure side of the double-pipe heat exchanger 13 is surely in a supercooled state. That is, the first temperature detector 21
Detects the temperature at the outlet of the second electric expansion valve 120 (T
1) and the temperature (T2) at the inlet of the second electric expansion valve 120 detected by the second temperature detector 24 is fetched, and this differential temperature (T2-T1) is calculated. Further, an opening correction value of the second electric expansion valve 120 is calculated by feedback control such as PID control so that the temperature difference becomes equal to or less than a predetermined value (for example, 10 ° C.), and the opening command is transmitted to the second electric expansion valve. Output to valve 120. As a result, the refrigerant at the outlet on the high pressure side of the double pipe heat exchanger 13 is surely in a supercooled state, and the bypass pipe 11
To minimize the energy loss of the refrigeration cycle.

On the other hand, during the cooling operation, the refrigerant circulates in the direction of the dashed arrow in FIG.
The indoor heat exchanger 61 serves as an evaporator to perform cooling. The rotation speed of the compressor 1 is controlled such that the evaporation pressure matches the target value. The target evaporation pressure is, for example, the evaporation temperature Te.
Is obtained as a pressure at which the temperature becomes 0 ° C. This evaporation pressure target value P
e is obtained from Expression (4) as in the heating operation. Accordingly, the control device 40 calculates the evaporation pressure target value Pe using the circulating composition signal α transmitted from the composition calculator 30. Further, in the control device 40, according to the difference between the pressure P1 detected by the first pressure detector 22 and the evaporation pressure target value Pe,
A correction value of the rotation speed of the compressor 1 is calculated by feedback control such as PID control, and the compressor rotation speed command is
Is output to

The number of revolutions of the outdoor blower 53 is controlled so that the condensing pressure matches the target value. The target condensing pressure value is obtained, for example, as a pressure at which the condensing temperature Tc becomes 50 ° C. This condensing pressure target value Pc is, as in the heating operation,
It is obtained from equation (3). Accordingly, the controller 40 calculates the condensing pressure target value Pc using the circulating composition signal α transmitted from the composition calculator 30. Further, in the control device 40, a correction value of the rotation speed of the outdoor blower 53 is calculated by feedback control such as PID control according to a difference between the pressure P2 detected by the second pressure detector 26 and the condensing pressure target value Pc, The outdoor blower rotation speed command is output to the outdoor blower 53.

The degree of opening of the first electric expansion valve as the first pressure reducing device 3 is controlled so that the degree of superheat at the outlet of the indoor heat exchanger 61 becomes a predetermined value, for example, 5 ° C. This degree of superheat can be obtained as the difference between the saturated steam temperature at the pressure in the indoor heat exchanger 61 and the outlet temperature of the indoor heat exchanger 61. The saturated steam temperature is determined by the pressure and the circulation composition as shown in FIG. It can be obtained as a function. Therefore, in the control device 40,
If the relationship of FIG. 26 is stored in advance in the control device 40 as a relational expression of Tdew = f ₆ (P1, α) (6), the composition calculation is performed using the expression (6). The saturated steam temperature Tdew and the indoor heat exchange are obtained using the circulating composition signal α transmitted from the heater 30, the pressure signal P1 transmitted from the first pressure detector 22 and the temperature signal T5 transmitted from the fifth temperature detector 63. The degree of superheat at the outlet of the vessel 61 (T5−Tdew) is calculated. Further, the controller 40 corrects the opening degree of the first electric expansion valve, which is the first pressure reducing device 3, by feedback control such as PID control according to the difference between the degree of superheat at the outlet and a predetermined value (5 ° C.). Is calculated, and the electric expansion valve opening command is output to the first electric expansion valve which is the first pressure reducing device 3.

Since the opening control of the second electric expansion valve 120 is the same as that in the heating operation, the description is omitted here. Next, the operation of the comparison calculator 41 will be described. The comparison calculator 41 takes in the circulating composition signal from the composition calculator 30 and determines whether or not this circulating composition is within a previously stored proper circulating composition range, and determines whether the circulating composition is within the proper circulating composition range. If so, the operation continues. On the other hand, if the circulating composition changes due to refrigerant leakage during use, or the circulating composition changes due to a malfunction during charging of the refrigerant, the comparison arithmetic unit 4
In 1, when it is determined that the circulating composition is out of the proper circulating composition range stored in advance, an alarm signal is transmitted to the alarm device 42. Upon receiving the warning signal, the warning device 42 issues a warning for a predetermined time to warn that the circulating composition of the non-azeotropic refrigerant mixture of the refrigeration / air-conditioning device is out of the proper range.

In this embodiment, the number of revolutions of the outdoor blower 53 during the heating operation is controlled so that the value of the first pressure detector 22 matches the target evaporating pressure value calculated from the circulation composition. However, the same effect can be obtained by providing a temperature detector at the inlet of the outdoor heat exchanger 52 and controlling the temperature to be a predetermined value (for example, 0 ° C.).

In the present embodiment, the opening degree of the first electric expansion valve, which is the first pressure reducing device 3 during the cooling operation, is set to a predetermined value (for example, 5 ° C.) at the outlet superheat degree of the indoor heat exchanger 61. In the above description, the control is performed so that the indoor heat exchanger 6 is controlled.
1 so that the inlet / outlet temperature difference becomes a predetermined value (for example, 10 ° C.), that is, the fifth temperature detector 63 and the fourth temperature detector 6
The same effect can be obtained even if the difference in temperature is controlled to be a predetermined value.

Further, in this embodiment, one outdoor unit 50
Refrigeration and air-conditioning system in which two indoor units 60 are connected to the above, but the present invention is not limited to this, and only one indoor unit is connected, or three or more indoor units are connected. However, the same effect can be obtained.

[0068]

As described above, according to the first aspect of the present invention, the composition of the refrigerant circulating in the refrigeration cycle is calculated from the signals detected by the temperature detector and the pressure detector. Even if the circulating composition changes due to changes in the operating conditions and load conditions of the air conditioner, or if the circulating composition changes due to a refrigerant leak during use of the refrigeration air conditioner or a malfunction during the charging of the refrigerant, the circulating composition in the cycle is changed. There is an effect that a refrigeration air conditioner using a non-azeotropic mixed refrigerant that can be accurately detected can be obtained.

According to the present invention, the composition of the refrigerant circulating in the refrigeration cycle is calculated from the signals detected by the first temperature detector, the second temperature detector, and the pressure detector. Even if the circulating composition changes due to changes in the operating conditions and load conditions of the refrigeration / air-conditioning system, or if the circulating composition changes due to refrigerant leakage during use of the refrigeration / air-conditioning system or a malfunction during the charging of the refrigerant, the circulating composition in the cycle is changed. This has the effect of obtaining a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant capable of accurately detecting the temperature.

According to the third aspect of the present invention, the composition of the refrigerant circulating in the refrigeration cycle is calculated from the signals detected by the plurality of temperature detectors and the pressure detectors. Even if the circulating composition changes due to changes in conditions or load conditions, or if the circulating composition changes due to a refrigerant leak during use of a refrigeration / air-conditioning device or a malfunction when filling the refrigerant, the circulating composition in the cycle is accurately detected. There is an effect that a refrigeration air conditioner using a non-azeotropic mixed refrigerant which can be obtained.

According to the fourth aspect of the present invention, since the heat is exchanged between the high-pressure side and the low-pressure side as a method of cooling the bypass pipe, the structure of the refrigeration / air-conditioning apparatus can be made compact and non-azeotropic. There is an effect that a refrigerating air conditioner using a refrigerant can be obtained.

According to the present invention, the composition of the refrigerant circulating in the refrigeration cycle is calculated from a plurality of temperature detectors for detecting the temperature of the low-pressure side refrigerant and signals detected by the pressure detectors. Therefore, even if the circulating composition changes due to changes in the operating conditions or load conditions of the refrigeration / air-conditioning system, or if the circulating composition changes due to refrigerant leakage during use of the refrigeration / air-conditioning device or malfunction during filling of the refrigerant, the cycle This has the effect of obtaining a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant capable of accurately detecting the circulating composition of the air.

According to the sixth aspect of the present invention, the compressor, the first pressure reducing device, and the like are controlled in accordance with the refrigerant composition detected by the composition computing unit. Refrigeration using a non-azeotropic mixed refrigerant that enables optimal operation even if the circulation composition changes due to changes in the refrigerant, or if the circulation composition changes due to refrigerant leakage during use of the refrigeration air conditioner or malfunctions when charging the refrigerant. There is an effect that an air conditioner can be obtained.

According to the seventh aspect of the present invention, when the circulating composition is out of the predetermined range, the alarm device is activated by a warning signal. Or a change in the circulation composition due to a malfunction at the time of charging the refrigerant, and it is possible to obtain a refrigeration and air-conditioning system using a non-azeotropic mixed refrigerant with high safety and reliability.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram illustrating a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a state change of a refrigerant according to a first embodiment of the present invention on a pressure-enthalpy diagram.

FIG. 3 is a diagram showing a relationship between a temperature and a composition of a non-azeotropic mixed refrigerant according to Embodiment 1 of the present invention.

FIG. 4 is a diagram showing a relationship between a saturated liquid temperature and a circulation composition of a non-azeotropic refrigerant mixture according to Embodiment 1 of the present invention.

FIG. 5 is a diagram showing the relationship between the temperature and the dryness of the non-azeotropic refrigerant mixture according to Embodiment 1 of the present invention.

FIG. 6 is a refrigerant circuit diagram showing a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 2 of the present invention.

FIG. 7 is a diagram showing a state change of a refrigerant according to a second embodiment of the present invention on a pressure-enthalpy diagram.

FIG. 8 is a flowchart showing the operation of the composition calculator according to Embodiment 2 of the present invention.

FIG. 9 is a diagram showing a relationship between dryness, temperature and pressure of a non-azeotropic mixed refrigerant according to Embodiment 2 of the present invention.

FIG. 10 is a graph showing a temperature at a gas-liquid two-phase dryness X of a non-azeotropic mixed refrigerant according to Embodiment 2 of the present invention.

FIG. 11 is a diagram showing a temperature and a circulation composition at a gas-liquid two-phase dryness X of a non-azeotropic mixed refrigerant according to Embodiment 2 of the present invention.

FIG. 12 is a refrigerant circuit diagram illustrating a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 3 of the present invention.

FIG. 13 is a refrigerant circuit diagram showing a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 4 of the present invention.

FIG. 14 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 5 of the present invention.

FIG. 15 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 6 of the present invention.

FIG. 16 is a diagram illustrating a temperature change of a double-pipe heat exchanger according to Embodiment 6 of the present invention.

FIG. 17 is a diagram showing a relationship between a temperature of a non-azeotropic refrigerant mixture and a circulation composition according to Embodiment 6 of the present invention.

FIG. 18 is a refrigerant circuit diagram illustrating a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 7 of the present invention.

FIG. 19 is a diagram illustrating a temperature change of a heat exchanger according to Embodiment 7 of the present invention.

FIG. 20 is a diagram showing a relationship between a temperature of a non-azeotropic refrigerant mixture and a circulation composition according to Embodiment 7 of the present invention.

FIG. 21 is a refrigerant circuit diagram showing a refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant according to Embodiment 8 of the present invention.

FIG. 22 is a control block diagram of a refrigeration and air-conditioning system using a non-azeotropic refrigerant mixture according to Embodiment 8 of the present invention.

FIG. 23 is a diagram showing a relationship between a condensing pressure of a non-azeotropic refrigerant mixture and a circulation composition according to Embodiment 8 of the present invention.

FIG. 24 is a diagram showing a relationship between an evaporation pressure of a non-azeotropic mixed refrigerant and a circulation composition according to Embodiment 8 of the present invention.

FIG. 25 is a diagram showing a relationship among a saturated liquid temperature, a pressure, and a circulation composition of a non-azeotropic refrigerant mixture according to Embodiment 8 of the present invention.

FIG. 26 is a diagram showing a relationship between a saturated vapor temperature, a pressure, and a circulation composition of a non-azeotropic refrigerant mixture according to Embodiment 8 of the present invention.

FIG. 27 is a configuration diagram showing a configuration of a conventional refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 compressor, 2 condenser, 3 first decompression device, 4 evaporator, 11 bypass pipe, 12 second capillary tube (second decompression device), 13 double-tube heat exchanger (cooling means), 21 first temperature detection (Temperature detector), 22 first pressure detector (pressure detector), 24 second temperature detector, 25a, 25
b, 25c, 25d, 25e Temperature detector, 26 second
Pressure detector (pressure detector), 30 Composition calculator, 40
Control device, 41 comparison operation unit (comparison operation means), 42
Alarm device, 120 electric expansion valve (second pressure reducing device).

Claims (7)

(57) [Claims] 1. A refrigeration cycle in which a compressor, a condenser, a first decompression device, and an evaporator are sequentially connected by a refrigerant pipe that circulates using a non-azeotropic mixed refrigerant as a refrigerant, and an outlet of the compressor. And a bypass pipe connecting and connecting a high-pressure side from the first pressure-reducing device to a low-pressure side from the first pressure-reducing device to the compressor inlet via a second pressure-reducing device; (2) cooling means for cooling the non-azeotropic mixed refrigerant flowing into the pressure reducing device; a temperature detector and a pressure detector for detecting the temperature of the low pressure side refrigerant and the pressure of the low pressure side refrigerant at the outlet of the second pressure reducing device; A refrigeration air conditioner using a non-azeotropic mixed refrigerant, comprising: a composition calculator for calculating a composition of a refrigerant circulating in the refrigeration cycle from signals detected by the temperature detector and the pressure detector. 2. A refrigeration cycle in which a compressor, a condenser, a first decompression device, and an evaporator are sequentially connected by a refrigerant pipe that circulates using a non-azeotropic mixed refrigerant as a refrigerant, and an outlet of the compressor. And a bypass pipe connecting and connecting a high-pressure side from the first pressure-reducing device to a low-pressure side from the first pressure-reducing device to the compressor inlet via a second pressure-reducing device; (2) cooling means for cooling the non-azeotropic mixed refrigerant flowing into the pressure reducing device, a first temperature detector and a pressure detector for detecting the temperature of the low pressure side refrigerant and the pressure of the low pressure side refrigerant at the outlet of the second pressure reducing device Detector, a second temperature detector for detecting the temperature of the high-pressure side refrigerant at the inlet of the second pressure reducing device, and a signal detected by the first temperature detector and the pressure detector and the second temperature detector. And a composition calculator for calculating the composition of the refrigerant circulating in the refrigeration cycle. 3. A refrigeration cycle in which a compressor, a condenser, a first decompression device, and an evaporator are sequentially connected by a refrigerant pipe that circulates using a non-azeotropic mixed refrigerant as a refrigerant, and an outlet of the compressor. And a bypass pipe connecting and connecting a high-pressure side from the first pressure-reducing device to a low-pressure side from the first pressure-reducing device to the compressor inlet via a second pressure-reducing device; (2) cooling means for cooling the non-azeotropic mixed refrigerant flowing into the pressure reducing device, three or more temperature detectors for detecting the temperature of the high-pressure side refrigerant in the bypass pipe, and detecting the pressure of the high-pressure side refrigerant in the bypass pipe And a composition calculator for calculating the composition of the refrigerant circulating inside the refrigeration cycle from signals detected by the three or more temperature detectors and the pressure detector. Refrigeration air conditioner using a non-azeotropic mixed refrigerant provided. 4. The cooling device according to claim 1, wherein the cooling unit is configured to exchange heat between a high pressure side and a low pressure side of the bypass pipe. A refrigeration air conditioner using a non-azeotropic mixed refrigerant. 5. A refrigeration cycle in which a compressor, a condenser, a first decompression device, and an evaporator are sequentially connected by a refrigerant pipe that circulates using a non-azeotropic mixed refrigerant as a refrigerant, and an outlet of the compressor. A bypass pipe connecting and connecting a high-pressure side from the first pressure-reducing apparatus to a low-pressure side from the first pressure-reducing apparatus to the compressor inlet via a second pressure-reducing apparatus; and a high-pressure side and a low-pressure side of the bypass pipe. A heat exchange unit for exchanging heat between the bypass pipe, three or more temperature detectors for detecting the temperature of the low-pressure refrigerant in the bypass pipe, and a pressure detector for detecting the pressure of the low-pressure refrigerant in the bypass pipe; Refrigeration air using a non-azeotropic mixed refrigerant, comprising: a composition calculator for calculating the composition of a refrigerant circulating inside the refrigeration cycle from signals detected by the temperature detectors and the pressure detectors. Control device. 6. A refrigeration cycle, comprising a control device for controlling the operation of each means of the refrigeration cycle, wherein the control device controls the operation of the refrigeration cycle in accordance with the refrigerant composition detected by the composition calculator. A refrigeration / air-conditioning apparatus using the non-azeotropic mixed refrigerant according to any one of claims 1 to 5. 7. A comparison operation means for issuing a warning signal when the refrigerant composition detected by the composition operation unit is out of a predetermined range, and an alarm device operated by the alarm signal issued by the comparison operation means. A refrigeration and air-conditioning system using the non-azeotropic mixed refrigerant according to any one of claims 1 to 6.