JP2002195675A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner, in which the efficiency of heat exchange by heating tubes is improved, when heat exchangers are used compressor or an evaporator, and capacities of condensation and evaporation are enhanced to attain an improved cooling/heating operation. SOLUTION: Heat exchangers 3, 7, having non-azeotropic refrigerant as refrigerant, are used respectively as an evaporator or a condenser in the cooling mode or heating mode. In the heat exchangers, there are provided heating tubes, having a co-current refrigerant flow with the air flow passing through the heat exchangers 3, 7 and heating-tubes having a flow which becomes counter flow to the air flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner using a non-azeotropic mixed refrigerant as a refrigerant.

[0002]

2. Description of the Related Art Generally, an air conditioner is composed of a compressor, a use side heat exchanger, a decompression device, and a heat source side heat exchanger. In a cooling mode, the use side heat exchanger is used as an evaporator. The heat source side heat exchanger is used as a condenser. In the heating mode, a refrigeration cycle is configured in which the use-side heat exchanger is used as a condenser and the heat-source-side heat exchanger is used as an evaporator, and the refrigerant circulates in the cycle.

[0003]

The refrigerant circulating in the refrigeration cycle generally uses chlorofluorocarbon gas and tends to be completely eliminated from places that have a bad influence on the global environment. Boiling mixed refrigerants are considered promising.

[0004] The non-azeotropic refrigerant mixture has a phenomenon that in the refrigeration cycle, the evaporation temperature and the condensation temperature change in the evaporation process and the condensation process due to the difference in the boiling point of each refrigerant. This is called a temperature gradient.

[0005] In the evaporator of the refrigerant circuit, the refrigerant liquid becomes refrigerant vapor while maintaining the gas-liquid equilibrium. During this time, the evaporation temperature gradually rises. In a condenser, the opposite is true, and the condensation temperature gradually decreases. On the other hand, the air is deprived of heat in the evaporator and becomes low temperature, and the air obtains heat and becomes high temperature in the condenser. Table 1 summarizes these temperature relationships.

[0006]

[Table 1] The refrigerant circuit of this non-azeotropic mixed refrigerant performs heat exchange in a counter-flow system, thereby utilizing the characteristic that the phase change temperature depends on the concentration to reduce the heat exchange loss of the refrigerant with a cool air fluid or a heated fluid. Can be reduced and the coefficient of performance can be improved. In the counterflow method, the inlet of the refrigerant is in the most leeward row, the outlet is in the most leeward row, and the refrigerant is arranged so that the refrigerant flows sequentially from the leeward row to the leeward row. This is the case. The reverse case is called a parallel flow system, and when used as a condenser, a counter flow is used.
Japanese Patent Application Laid-Open No. Sho.
And JP-A-63-302264 have been proposed.

However, in the former case, when the use side heat exchanger is used as a condenser, if it is set as a counter flow, the flow becomes parallel when used as an evaporator, so that the heat exchange efficiency in the cooling mode is reduced. This leads to a deteriorating problem.

In the case of the latter, the number of control valves and circuits for controlling the flow of the refrigerant is increased and complicated, which is not desirable in terms of assemblability and cost performance. There is a problem that efficiency loss occurs due to

When a refrigerant having a temperature gradient is used,
In addition to the change in heat exchange rate due to the pure heat transfer phenomenon due to the counterflow or parallel flow, it is necessary to consider that when used as a heat exchanger (evaporator) for cooling air, the water vapor in the air to be cooled is Consideration must be given to the reduction in heat exchange due to the reduction in ventilation due to the increase in ventilation resistance due to condensation. Water vapor in the parallel flow air where the difference between the fin and the inlet air temperature in the evaporator becomes large condensed and condensed on the front end surface of the fin, narrowing the passage between the fins, and reducing the amount of heat exchange due to the decrease in air volume . On the contrary, it is known that, in the case of the opposed flow which becomes smaller, the amount of water vapor dew condensation on the front end of the fin is smaller than that of the former, and dew condensation is more averaged from the center to the rear end.

Accordingly, an object of the present invention is to provide an air conditioner capable of performing efficient cooling operation and heating operation with a simple structure.

[0011]

According to the first aspect of the present invention, a heat exchanger is used as an evaporator or a condenser in a cooling mode or a heating mode. In an air conditioner using a non-azeotropic mixed refrigerant, a heat exchanger used as a condenser has a heat transfer tube in which the flow direction of the refrigerant is parallel to an air flow passing through the heat exchanger, and a counter flow. And a heat transfer tube.

According to a second aspect of the present invention, in a cooling mode or a heating mode, the heat exchanger is used as an evaporator in an air conditioner using a non-azeotropic mixed refrigerant used as an evaporator or a condenser. The heat exchanger includes a heat transfer tube in which the flow direction of the refrigerant is parallel to the air flow passing through the heat exchanger, and a heat transfer tube in which the flow direction is counter flow.

According to a third aspect of the present invention, the refrigerant inlet and the refrigerant outlet of the heat transfer tube of the heat exchanger are arranged on the windward side of the airflow passing through the heat exchanger and at the same position. It is characterized by the following.

According to a fourth aspect of the present invention, the refrigerant inlet and the refrigerant outlet of the heat transfer tube of the heat exchanger are close to each other.

[0015]

In such an air conditioner, the heat exchanger used as a condenser has a slightly reduced heat exchange efficiency in a parallel flow, but the supercooled condensate is efficiently cooled in a counter flow. As a result, heat exchange efficiency is improved, condensing capacity is secured comprehensively, and efficient cooling and heating operations can be performed with a simple structure.

According to the second aspect of the present invention, in the heat exchanger used as the evaporator, the heat exchange efficiency is slightly lowered in the parallel flow, but the heat exchange efficiency is improved in the counter flow, and the overall evaporation capacity is improved. And efficient cooling and heating operations can be performed with a simple structure.

According to the third aspect of the present invention, the refrigerant inlet and the refrigerant outlet of the heat transfer tube of the heat exchanger are arranged on the windward side of the airflow passing through the heat exchanger and at the same position. Therefore, when used as a condenser, the refrigerant inlet and refrigerant outlet of the heat transfer tube exchange heat with low-temperature air on the windward side, so that supercooling can be reliably achieved with a simple structure, and as an evaporator. When used, the refrigerant inlet and the refrigerant outlet of the heat transfer tube have an appropriate degree of superheat to exchange heat with high-temperature air on the windward side, and the efficiency of the compressor decreases due to the return of the wet refrigerant to the compressor and the life of the compressor. Problems such as deterioration can be solved with a simple structure.

In the present invention, since the refrigerant inlet and the refrigerant outlet of the heat transfer tube of the heat exchanger used as the evaporator are brought close to each other, heat exchange occurs between the refrigerant and the heat generated during the low temperature operation. As a result of eliminating the frost, freezing phenomenon, or condensation phenomenon, it is possible to secure an efficient ventilation with a simple structure.

[0019]

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

First, referring to FIGS. 1 and 2, FIG. 1 shows a piping diagram of a heat pump type air conditioner using a non-azeotropic mixed refrigerant such as R32 and R134a as the refrigerant. .

The air conditioner includes a compressor 1, a use side heat exchanger 3, a pressure reducing device 5, and a heat source side heat exchanger 7.
By operating the four-way valve 9 in accordance with the cooling / heating mode, the refrigerant discharged from the compressor 1 is directed to the use-side heat exchanger 3 as indicated by a dotted arrow, or to the heat source-side heat exchanger as indicated by a solid arrow. A refrigeration cycle having a flow toward the side 7 is configured, and switching control corresponding to the operation mode is possible.

The use side heat exchanger 3 includes a continuous heat transfer tube 11
And the fins 13 arranged at a predetermined pitch. The refrigerant functions as an evaporator when the refrigerant flows through the circuit 15 as indicated by a solid arrow, and functions as a condenser when the refrigerant flows as indicated by a dotted arrow. .

The air flow flows as shown by the arrow as the cross flow fan 17 rotates, and passes between the fins 13. The a side is the leeward side and the b side is the leeward side.

A terminal 19 on the windward a side of the heat transfer tube 11 of the use side heat exchanger 3 is connected to the four-way valve 9, and a terminal 21 on the leeward b side of the heat transfer tube 11 is connected to the pressure reducing device 5. Communicating. Thereby, in the cooling mode, the terminal portion 21 on the leeward side b is connected to the terminal portion 19 on the leeward side of the refrigerant.
Is set to be a counter flow on the outlet side, and in the heating mode, the terminal portion 19 on the upwind side a is on the inlet side of the refrigerant,
The terminal 21 on the side is set to be in a parallel flow on the exit side.

The heat source side heat exchanger 7 includes a continuous heat transfer tube 23
And the fins 25 arranged at a predetermined pitch. The refrigerant functions as a condenser by flowing through the circuit 15 as indicated by a solid arrow, and functions as an evaporator by flowing the refrigerant as indicated by a dotted arrow. The air flow flows as indicated by the arrow as the fan 27 rotates, and passes between the fins 25. The a side is the leeward side and the b side is the leeward side.

A terminal 29 on the windward a side of the heat transfer tube 23 of the heat source side heat exchanger 7 is connected to the four-way valve 9, and a terminal 31 on the leeward b side of the heat transfer tube 23 is connected to the pressure reducing device 5. Communicating. Thus, in the cooling mode, the terminal section 29 on the leeward side a is set to be in parallel with the inlet side of the refrigerant and the terminal section 31 on the leeward side is in the outlet side. In the heating mode, the terminal part on the leeward side b is set. Numeral 31 is set so that the terminal portion 29 on the inlet side of the refrigerant and on the windward side a has an opposite flow on the outlet side.

In the air conditioner thus configured, in the cooling mode, the high-temperature and high-pressure refrigerant vapor discharged from the compressor 1 enters the heat source side heat exchanger 7 through the four-way valve 9, and the outdoor air Heat and condense. The condensed refrigerant is decompressed by the decompression device 5, becomes low temperature and low pressure, and absorbs heat from indoor air in the use side heat exchanger 3 to be vaporized. The vaporized refrigerant is sucked into the compressor 1, becomes high-temperature and high-pressure vapor again, and repeats the refrigeration cycle. On the other hand, in the heat pump heating mode, the high-temperature and high-pressure refrigerant vapor discharged from the compressor 1 first enters the use side heat exchanger 3 via the four-way valve 9 and radiates heat to room air to be condensed. The condensed refrigerant is decompressed by the decompression device 5 to become low temperature and low pressure, and the heat source side heat exchanger 7 absorbs heat from the outdoor air to vaporize. The vaporized refrigerant is sucked into the compressor 1, becomes high-temperature and high-pressure steam again, and repeats the heating cycle.

In the cooling mode and the heating mode, in the operation mode in which both the use-side heat exchanger 3 and the heat-source-side heat exchanger 7 are used as evaporators, the flow becomes countercurrent, and the heat exchanger 3 operates as a condenser. When used, it is a parallel flow. In this case, since the temperature difference between the inlet side and the outlet side is small in the evaporator having the counterflow, the amount of water vapor dew condensation on the front end of the fin is suppressed to be small as a whole, and no decrease in the ventilation amount is observed. In this way, the cooling and heating operation with high efficiency can be performed comprehensively.

FIG. 2 shows the result. In FIG. 2, in the condenser, the flow becomes parallel due to the configuration and becomes negative, but this is a value that can be recovered by increasing the number of fins.

In general, when the number of fins is increased, ventilation resistance increases when the fin is used as an evaporator, and performance is reduced. Therefore, the performance when used as a condenser can be sufficiently improved.

FIG. 3 shows a piping diagram of an air conditioner according to the present invention, which is characterized by the arrangement of a refrigerant inlet and a refrigerant outlet.

That is, terminals 19 and 21 serving as a refrigerant inlet and a refrigerant outlet of the heat transfer tube 11 of the use side heat exchanger 3 and terminal portions serving as a refrigerant inlet and a refrigerant outlet of the heat transfer tube 23 of the heat source side heat exchanger 7. 29 and 31 are arranged on the windward a side, respectively, and on the windward a side, they are arranged at the same position and close to the vertical axis in the drawing.

In the heat transfer tube 11 of the use side heat exchanger 3,
One terminal 19 is connected to the heat source side heat exchanger 7 through a four-way valve.
One end portion 29 of the heat transfer tube 23 and the other end portion 21 are connected to the other end portion 31 of the heat transfer tube 23 serving as the heat source side heat exchanger 7 via the decompression device 5, respectively. Is composed.

Therefore, the use-side heat exchanger 3 and the heat-source-side heat exchanger 7 are connected in the cooling mode or the heating mode.
When the refrigerant discharged from the compressor 1 flows through the four-way valve 9 as shown by a solid arrow or a dotted arrow, the refrigerant functions as an evaporator or a condenser.

Regarding this point, first, the use side heat exchanger 3
Will be specifically described.

In the cooling mode, the refrigerant flows as indicated by the solid arrows, thereby functioning as an evaporator. The terminal 21 of the heat transfer tube 11 serves as a refrigerant inlet, and the terminal 19 serves as a refrigerant outlet. Looking at the heat transfer tube 11 at this time, the lower half of the heat transfer tube 11 disposed in parallel with the terminal portion 21 serving as the refrigerant inlet in the drawing shows the flow of the refrigerant with respect to the air flow passing through the heat exchanger 3. The direction is a heat transfer tube region in which the flow is parallel. In addition, the upper half of the heat transfer tube 11 disposed in parallel with the terminal portion 19 serving as a refrigerant outlet is provided with a heat transfer tube region in which the flow direction of the refrigerant is opposite to the air flow passing through the heat exchanger 3. Has become.

On the other hand, in the heating mode, the refrigerant discharged from the compressor 1 flows as shown by a dotted arrow, so that the use-side heat exchanger 3 functions as a condenser,
Reference numeral 9 denotes a refrigerant inlet, and the terminal 21 is a refrigerant outlet. Referring to the heat transfer tube 11 at this time, in the figure, the upper half arranged in parallel with the terminal portion 19 serving as the refrigerant inlet has the refrigerant flowing direction parallel to the air flow passing through the heat exchanger 3. It is a heat transfer tube area that becomes a flow. In addition, the lower half arranged in parallel with the terminal portion 21 serving as the refrigerant outlet is a heat transfer tube region in which the flow direction of the refrigerant is opposite to the flow of air passing through the heat exchanger 3.

Next, the heat source side heat exchanger 7 will be specifically described.

In the cooling mode, the refrigerant flows as indicated by the solid line arrow, thereby functioning as a condenser. The terminal 29 of the heat transfer tube 23 serves as a refrigerant inlet, and the terminal 31 serves as a refrigerant outlet. Referring to the heat transfer tube 23 at this time, the upper half of the heat transfer tube 23 disposed in parallel with the terminal portion 29 serving as the refrigerant inlet in the drawing shows the flow of the refrigerant with respect to the air flow passing through the heat exchanger 7. The direction is a heat transfer tube region in which the flow is parallel. In addition, the lower half of the heat transfer tube 23 disposed in parallel with the terminal portion 31 serving as a refrigerant outlet is a heat transfer tube region where the flow direction of the refrigerant is in the counterflow with respect to the air flow passing through the heat exchanger 7. Has become.

On the other hand, in the heating mode, the refrigerant discharged from the compressor 1 flows as indicated by the dotted arrow, so that the heat source side heat exchanger 7 functions as an evaporator,
1 is a refrigerant inlet, and the terminal part 29 is a refrigerant outlet. Referring to the heat transfer tube 23 at this time, in the figure, the lower half arranged in parallel with the terminal portion 31 serving as the refrigerant inlet has a flow direction of the refrigerant parallel to the air flow passing through the heat exchanger 7. It is a heat transfer tube area that becomes a flow. The upper half arranged in parallel with the terminal part 29 serving as a refrigerant outlet is the heat exchanger 7.
The flow direction of the refrigerant is a heat transfer tube region in which the flow direction is opposite to the air flow passing through the heat transfer tube.

Therefore, when the heat exchanger 3 or 7 is used as a condenser, the heat exchange efficiency is slightly reduced by the heat transfer tubes 11 and 23 which are in a parallel flow, but the supercooling of the condensate is efficiently performed by the counter flow. As a result, the heat exchange efficiency is improved, the condensing capacity is secured comprehensively, and efficient cooling and heating operations can be performed with a simple structure.

When the heat exchanger 3 or 7 is used as an evaporator, the heat exchange efficiency is slightly reduced by the heat transfer tubes 11 and 23 which are in a parallel flow, but the heat exchange efficiency is improved by the counter flow and the overall flow is improved. As a result, a high efficiency cooling and heating operation can be performed with a simple structure.

On the other hand, for example, the refrigerant inlet and the refrigerant outlet of the heat transfer tube 11 of the use side heat exchanger 3 are located on the windward side with respect to the airflow passing through the heat exchanger 3 and at the same position. ,
When used as a condenser, the refrigerant inlet 19 and the refrigerant outlet 21 of the heat transfer tube 11 exchange heat with low-temperature air on the windward a side, so that supercooling can be reliably achieved with a simple structure. When used as an evaporator, the refrigerant inlet 21 and the refrigerant outlet 19 of the heat transfer tube 11 have an appropriate degree of superheat for exchanging heat with high-temperature air on the windward a side, and the wet refrigerant returns to the compressor 1. Thus, problems such as a reduction in efficiency and a reduction in the life of the compressor 1 can be solved with a simple structure.

When the heat exchanger 3 or 7 is used, for example, as an evaporator, the terminals 19 and 21 serving as the refrigerant inlet and the refrigerant outlet of the heat transfer tube 11 and the terminals 29 and 31 are brought close to each other. Therefore, heat exchange is performed between the refrigerant inlet and the refrigerant outlet, and frosting, freezing phenomenon, or dew condensation phenomenon that occurs during low temperature operation is eliminated, so that an efficient ventilation amount can be secured with a simple structure. Become.

In this case, by adopting the means shown in FIGS. 4 and 5, the capability can be further improved. That is, the terminal portions 19, 21, 29, 31 of the heat transfer tubes 11, 23 are moved upwind a.
On the heat transfer tube 11 side, each terminal portion 19,
The heat transfer tubes 11 are arranged apart from each other, and one terminal portion 21 is disposed adjacent to the heat transfer tube 11 on the windward side a. On the other side of the heat transfer tube 23, the terminal portions 29 and 31 are arranged apart from each other, and one terminal portion 31 is provided adjacent to the heat transfer tube 23 on the windward a side, and the use side and the heat source side. When the heat exchangers 3 and 7 are used as evaporators, the inlet side of the refrigerant is parallel to the air flow provided on the windward side, and the outlet side of the refrigerant is arranged on the windward side a. The outlet side region is a counter flow.

The other components are the same as those in the above embodiment, and the same reference numerals are used and the description is omitted.

According to this embodiment, in addition to the effect of the embodiment of FIG. 3, since the evaporator outlet side is arranged close to the lowest heat transfer tube on the inlet side, the influence of heat from the inlet side is reduced. And the loss of cooling capacity is kept small. Therefore, as shown by the solid line in FIG. 6, there is an advantage that the fin temperature on the inlet side increases and the fin temperature on the outlet side decreases, so that the fin temperatures can be efficiently averaged.

[0048]

As described above, according to the first aspect of the present invention, when the heat exchanger is used as a condenser,
The heat exchange efficiency is slightly reduced by the parallel flow, but the condensed liquid is efficiently supercooled by the counter flow to improve the heat exchange efficiency. , Heating operation can be performed.

According to the second aspect of the present invention, when the heat exchanger is used as an evaporator, the heat exchange efficiency is slightly reduced in the parallel flow, but the heat exchange efficiency is improved in the counter flow, and Efficient cooling operation and heating operation can be performed with a simple structure by ensuring evaporation efficiency.

According to the third aspect of the present invention, the refrigerant inlet and the refrigerant outlet of the heat transfer tube of the heat exchanger are located on the windward side with respect to the airflow passing through the heat exchanger and at the same position. Therefore, when used as a condenser, the refrigerant inlet and refrigerant outlet of the heat transfer tube exchange heat with low-temperature air on the windward side, so that supercooling can be reliably achieved with a simple structure, and as an evaporator. When used, the refrigerant inlet and the refrigerant outlet of the heat transfer tube have an appropriate degree of superheat to exchange heat with high-temperature air on the windward side, and the efficiency of the compressor decreases due to the return of the wet refrigerant to the compressor and the life of the compressor. Problems such as deterioration can be solved with a simple structure.

According to the fourth aspect of the present invention, since the refrigerant inlet and the refrigerant outlet of the heat transfer tube of the heat exchanger used as the evaporator are brought close to each other, they exchange heat with each other and generate during the low temperature operation. As a result, the frosting, freezing phenomenon or dew condensation phenomenon is eliminated, so that an efficient air flow can be secured with a simple structure.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram of a piping diagram showing an embodiment of an air conditioner.

FIG. 2 is an explanatory diagram showing a change in efficiency due to only a temperature gradient between an evaporator and a condenser and a change in efficiency due to ventilation resistance when a counter flow and a parallel flow are used.

FIG. 3 is a schematic explanatory view showing a piping diagram of the air conditioner according to the present invention.

FIG. 4 is an explanatory view similar to FIG. 3, showing a modified example of the inlet side and the outlet side of the refrigerant.

FIG. 5 is an explanatory view of a partial heat exchanger showing still another modification of FIG. 4;

FIG. 6 is an explanatory diagram showing temperatures at an inlet side and an outlet side of a heat transfer tube.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Compressor 3 Use side heat exchanger 5 Decompression device 7 Heat source side heat exchanger 9 Four way valve 11,23 Heat transfer tube 19,21 Terminal part which becomes a refrigerant inlet or a refrigerant outlet of one heat transfer tube side 29,31 The other heat transfer tube Terminal part which becomes refrigerant inlet or refrigerant outlet on the side a Upwind b Downwind

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuhiro Arai 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Living Space Systems Research Institute (72) Inventor Takayoshi Iwanaga 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Address Co., Ltd. Toshiba Living Space Systems Research Laboratory F-term (reference) 3L092 AA01 BA11 BA12 BA15 DA14 FA12 FA16

Claims (4)

[Claims] In a cooling mode or a heating mode, in an air conditioner using a non-azeotropic mixed refrigerant which uses a heat exchanger as an evaporator or as a condenser, a heat exchanger used as a condenser includes: An air conditioner comprising: a heat transfer tube in which a flow direction of a refrigerant is parallel to an air flow passing through a heat exchanger; 2. An air conditioner using a non-azeotropic mixed refrigerant that uses a heat exchanger as an evaporator or a condenser in a cooling mode or a heating mode, wherein the heat exchanger used as an evaporator is: An air conditioner comprising: a heat transfer tube in which a flow direction of a refrigerant is parallel to an air flow passing through a heat exchanger; 3. The heat exchanger according to claim 1, wherein a refrigerant inlet and a refrigerant outlet of the heat transfer tube of the heat exchanger are arranged on the windward side of an air flow passing through the heat exchanger and at the same position. The air conditioner according to claim 1 or 2. 4. The air conditioner according to claim 2, wherein the refrigerant inlet and the refrigerant outlet of the heat transfer tube of the heat exchanger are close to each other.