JP2005201491A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of obtaining a sufficient heat exchange amount by achieving optimum and high heat exchange performance in the case of using the heat exchanger with flat tubes passing through plate fins, as an evaporator or a condenser. <P>SOLUTION: In the flat tube 1, the number of cold passage holes 9a is reduced while enlarging the cross-sectional area of a refrigerant passage from the windward side A to the leeward side B. On the leeward side B, the heat transfer performance of a refrigerant to the air side through the fins 2 brought into close contact with the flat tubes 1 is thereby improved, and the heat exchange amount is increased. Even in the case of being used as the evaporator or condenser, heat exchange on the windward side A and leeward side B of the heat exchanger is performed in a well-balanced manner, and performance can be drawn out to the maximum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat exchanger used in a heat pump air conditioner, and more particularly to a heat exchanger that effectively uses the entire heat exchanger and can efficiently exchange heat between refrigerant and air.

  Conventionally, the fin-and-tube type heat exchanger constituting the refrigeration cycle of this type of air conditioner has a small amount of refrigerant circulation and a small pressure loss in the heat transfer tube when the heat exchange capacity is small. Therefore, a single refrigerant passage may be used, but when the amount of heat exchange is large, a large amount of refrigerant is circulated, and a plurality of refrigerant passages are required because the pressure loss in the heat transfer tube increases.

  Here, in FIG. 7, a case where a heat exchanger of a type using a flat tube having high heat exchange efficiency is used for the evaporator will be described. In the case of the conventional example shown in FIG. 7, reference numeral 4 denotes a hollow cylindrical header 4 whose lower side is closed, and when used as an evaporator, a connecting pipe 5 into which a refrigerant flows is joined to the upper side. The refrigerant flowing into the header 4 passes through the flat tubes 1 communicating with the headers, exchanges heat with air via the fins 2 that are in close contact with the flat tubes 1, and the gasified refrigerant is a hollow cylinder. It flows out from the connecting pipe 6 on the upper side of the header 3 that is shaped like a pipe.

  In addition, when this heat exchanger is used as a condenser, the direction of refrigerant flow differs depending on the switching of the four-way valve in the refrigeration cycle. In the case of the conventional example shown in FIG. 7, a single high-temperature and high-pressure discharged from the compressor is used. The superheated refrigerant gas of the phase flows into the header 3 from the connecting pipe 6 and passes through each flat pipe 1 communicating with each header, and exchanges heat with air through the fins 2 that are in close contact with each flat pipe 1. The refrigerant thus condensed and liquefied flows out from the connection pipe 5 of the condenser through the hollow cylindrical header 4. Reference numeral 1 denotes a flat tube for a heat exchanger having a flat cross-sectional outer shape made of a metal such as aluminum or copper alloy having good thermal conductivity, and has one or several refrigerant passages therein. To communicate with each other, a plurality of headers are attached horizontally by bridging their headers.

Conventionally, as a configuration example in which the heat exchange efficiency of such a heat exchanger for an air conditioner is improved, the shape of fins on the upstream side and the downstream side of the air is changed during the frosting operation with a single row of heat exchangers. In the heat exchanger that can efficiently operate the entire heat exchanger (see, for example, Patent Document 1) and the fin-and-tube type heat exchanger, the positions of the fins are in the first and second rows. Some of them are shifted between the heat exchangers (see, for example, Patent Document 2).
JP-A-8-178366 (page 4, Fig. 1) JP-A-7-198166 (page 3, Fig. 1)

  Generally, when a flat tube heat exchanger is used, the heat exchange performance is higher than that of a conventional fin-and-tube type heat exchanger. However, the process of heat exchange between air and refrigerant by the fin-and-tube heat exchanger composed of two rows is between the first row heat exchanger arranged on the windward side and the second row heat exchanger on the leeward side. Unlike a fin-and-tube, a flat-tube heat exchanger can be configured with multiple tubes in a single tube, whereas the refrigerant can easily cross and efficiently exchange heat with air. There is a refrigerant flow path partitioned by walls, and the refrigerant flows through the refrigerant flow path. Therefore, it is impossible to flow the refrigerant flowing through the refrigerant flow path on the windward side and the leeward side in a single tube. Since most of the heat exchange between the air side and the refrigerant side is preferentially heat exchanged on the windward side, the amount of heat exchange between the air side and the refrigerant in the heat exchanger on the leeward side becomes small.

Therefore, for example, in an evaporator, the heat exchanger on the leeward side can take a large degree of superheat, while the leeward side conversely reduces the amount of heat exchange to reduce the degree of superheat, and depending on the circulation amount of the refrigerant, the windward side and leeward side The heat exchange amount of the heat exchanger is greatly different and the balance is lost, so that the entire heat exchanger cannot be used effectively, and the performance of the refrigeration cycle may be lowered.

  In other words, even if the microtube heat exchangers are configured in two rows, it is difficult to make a configuration in which the refrigerant flowing through the first and second row heat exchangers intersects in the middle like fin-and-tube. Even if it is to be realized, there is a problem that the performance of the heat exchanger is greatly deteriorated such that not only the apparatus is enlarged, but the cost becomes complicated and the cost is further increased, and further, the refrigerant flow is broken.

  The present invention solves such a conventional problem, and even when a flat tube heat exchanger is used as an evaporator or a condenser, it achieves an optimum and high heat exchange performance and a sufficient heat exchange amount. It aims at providing the heat exchanger which can be obtained.

  In order to solve the conventional problems, a heat exchanger according to the present invention includes a pair of headers extending at a predetermined distance, and a plurality of refrigerant circulation holes through which refrigerant flows between the pair of headers. In a heat exchanger comprising: a flat tube formed of: a plurality of plate fins arranged at the same pitch that are substantially perpendicular to and in close contact with the flat tube; and a configuration in which the flat tube penetrates the plate fin. The flow path of the flat tube is a low performance type on the leeward side and a high performance type on the leeward side. The shape of this heat exchanger is intended to efficiently perform heat exchange of the entire heat exchanger and maximize the performance of the heat exchanger.

  When the heat exchanger of the present invention is used as an evaporator or a condenser, the heat exchangers on the windward and leeward sides are effectively used for heat exchange, so that the heat exchange performance is maximized without requiring a complicated configuration. In addition, when the heat exchanger is an evaporator for heating and low temperature, sudden clogging that occurs as the heat exchanger performance deteriorates due to concentrated frost formation on the windward side Therefore, it is possible to extend the time until clogging due to frost formation, and to improve the operating efficiency of the heating and low temperature, it is possible to provide a heat exchanger that realizes a highly efficient operation.

  According to a first aspect of the present invention, there is provided a pair of headers extending at a predetermined distance, a flat tube in which a plurality of refrigerant flow holes through which a refrigerant flows is formed between the pair of headers, and the flat tube A heat exchanger comprising a plurality of plate fins arranged substantially at right angles and in close contact with each other at the same pitch, and a structure in which the flat tube penetrates the plate fin, wherein the flow path of the flat tube is on the windward side By arranging a low performance type and a high performance type on the leeward side, highly efficient heat exchange can be performed even on the leeward side where the amount of heat exchange is smaller than that on the leeward side.

  According to a second aspect of the present invention, there is provided a pair of headers extending at a predetermined distance, a flat tube in which a plurality of refrigerant flow holes through which a refrigerant flows is formed between the pair of headers, and the flat tube A heat exchanger comprising a plurality of plate fins arranged substantially at right angles and in close contact with each other at the same pitch, and a structure in which the flat tube penetrates the plate fin, wherein the flow path of the flat tube is on the windward side By gradually disposing the high performance type from the low performance type from the leeward side to the leeward side, the refrigerant and air exchange heat efficiently and efficiently from the windward side where the heat exchange amount is high to the leeward side where the heat exchange amount is low. Can do.

  According to the third aspect of the present invention, by providing fins inside the refrigerant flow hole on the leeward side of the flat tube, the heat transfer performance that the refrigerant transmits to the air is improved even on the leeward side where the amount of heat exchange is smaller than that on the windward side. Therefore, highly efficient heat exchange can be performed.

  According to a fourth aspect of the present invention, the fins in the refrigerant flow hole on the leeward side of the flat tube are provided more than on the leeward side so that the refrigerant is transmitted to the air even on the leeward side where the amount of heat exchange is smaller than that on the leeward side. Since heat transfer performance is also improved, highly efficient heat exchange can be performed.

  According to a fifth aspect of the present invention, the fins are gradually increased from the windward side to the leeward side of the flat tube so that the fins gradually increase, so that the heat exchange amount from the windward side where the heat exchange amount is low to the leeward side portion where the heat exchange amount is low. As the refrigerant flow rate increases, the heat transfer performance also gradually improves, so that the refrigerant and air can effectively exchange heat.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a perspective view showing a part of the heat exchanger according to the first embodiment of the present invention, and FIG. 2 is a heat exchanger according to the first embodiment of the present invention as seen from the direction of arrow A in FIG. FIG.

2, three rectangular refrigerant passage holes 9a (for example, a cross-sectional area of 3 mm ² ) are provided on the windward side A1 of the flat tube 1 close to the windward, and the cross-sectional area of the refrigerant passage hole 9a of A1 is also provided on the leeward side B1. Six quadrant refrigerant passage holes 9b (for example, a cross-sectional area of 1.5 mm ² ) are provided. Therefore, the entire cross-sectional area of the refrigerant passage hole per one flat tube 1 is equivalent to both the leeward side A1 and the leeward side B1 (for example, a cross-sectional area of 9 mm ² ), but the leeward side B1 is more refrigerant than the leeward side A1. Since the surface area in the flow passage of the refrigerant passage hole 9b through which the refrigerant flows is larger, the surface area through which the refrigerant transfers heat from the fins 10 to the air via the flat tubes 1 is increased, so that the heat exchange efficiency is also increased.

  Therefore, normally, the air flowing in from the leeward A and the leeward side A1 of the heat exchanger exchange heat first, and then exchange heat with the leeward side B1. Therefore, in the leeward side B1, there is a temperature difference between the air side and the refrigerant. Since heat exchange is performed in a small state, the amount of heat exchange is also smaller on the leeward side B1. Therefore, since the heat transfer performance of the leeward side B1 is improved with the configuration of the first embodiment, the entire heat exchanger can exchange heat with the air side.

  Further, the shape of the flat tube 1 having higher heat exchange efficiency than the windward side A1 on the leeward side B1 enables the windward side A1 of FIGS. 7 and 2 even during the heating operation at a low outside temperature where frost formation occurs. Since the frost adheres to the fins 10 intensively and does not cause clogging, the frost easily adheres uniformly to the entire heat exchanger, so that the heating operation can be continued for a long time. The pair of headers extending at a predetermined distance are arranged in the vertical direction for the sake of explanation, but the same effect can be obtained even when arranged in the horizontal direction.

(Embodiment 2)
FIG. 3 is a cross-sectional view of the parallel flow heat exchanger according to the second embodiment of the present invention as seen from the direction of arrow B in FIG. The contents and principles that are the same as those in the above embodiment are omitted, and the same numbers are used in the following description to indicate the same functions.

In FIG. 3, it is possible to equalize the dryness of the heat exchanger outlet from the windward side A1 to the leeward side B1 by flowing the refrigerant flow rate gradually from the windward side A1 to the leeward side B1 of the heat exchanger. it can. For this purpose, as shown in FIG. 3, the cross-sectional area of the refrigerant passage hole 9c flowing through the leeward side A1 of the flat tube 1 is gradually reduced toward the leeward side B1, and 9c (for example, 8 mm ² )> 9d ( for example by 6mm ^2)> 9e (e.g. 5mm ^2)> 9f (eg 4mm ^2)> 9g (e.g. 3mm ^2)> 9h (e.g. 2 mm ^2)> be placed in the cross-sectional area such that 9i (e.g. 1 mm ²⁾ Only the outlet of the heat exchanger on the windward side A1 can be efficiently exchanged heat between the air and the refrigerant without extremely increasing the dryness, and the heat exchanger performance can be maximized.

  Therefore, normally, the air flowing in from the leeward side A and the leeward side A1 of the heat exchanger first exchange heat, and then exchange heat with the leeward side B1 of the heat exchanger. Since heat exchange is performed in a state in which the temperature difference of the refrigerant is small, the heat exchange amount is larger on the windward side A1, and the windward side A1 has a higher degree of dryness at the outlet of the heat exchanger, so that the windward side A1. The heat exchanger performance of the leeward side B1 cannot be sufficiently extracted. However, in the configuration of the second embodiment, the refrigerant flow rate gradually increases from the leeward side A1 to the leeward side B1. The heat transfer performance transferred to the air gradually increases, and the entire heat exchanger can exchange heat with the air side in a well-balanced manner.

(Embodiment 3)
FIG. 4 is a cross-sectional view of the parallel flow heat exchanger according to the third embodiment of the present invention as viewed from the direction of arrow B in FIG. The contents and principles that are the same as those in the above embodiment are omitted, and the same numbers are used in the following description to indicate the same functions.

  In FIG. 4, heat exchange between the leeward side A1 and the leeward side B1 is achieved by the refrigerant flowing through the leeward side B1 of the flat tube 1 of the heat exchanger having a higher heat transfer performance to be transmitted to the air than the windward side A1. The dryness of the vessel outlet can be made equal. For this purpose, as shown in FIG. 3, no internal fins are arranged in the refrigerant circulation hole 9j of the flat tube 1 on the leeward side A1, and internal fins 11 are arranged in the refrigerant circulation hole 9k on the leeward side B1. Only the outlet of the heat exchanger on the windward side A1 can be efficiently exchanged heat between the air and the refrigerant without extremely increasing the dryness, and the heat exchanger performance can be maximized.

  Therefore, normally, the air flowing in from the leeward side A and the leeward side A1 of the heat exchanger first exchange heat, and then exchange heat with the leeward side B1 of the heat exchanger. Since the heat exchange is performed in a state where the temperature difference is small, the amount of heat exchange is larger on the windward side A1, and the windward side A1 has a higher degree of dryness at the outlet of the heat exchanger. Although the heat exchanger performance of the leeward side B1 cannot be sufficiently extracted, the heat transfer performance on the refrigerant side of the leeward side B1 is improved with the configuration of the third embodiment, so that the entire heat exchanger is well balanced. It is possible to exchange heat with the air side.

(Embodiment 4)
FIG. 5 is a cross-sectional view of the parallel flow heat exchanger according to the fourth embodiment of the present invention as viewed from the direction of arrow B in FIG. The contents and principles that are the same as those in the above embodiment are omitted, and the same numbers are used in the following description to indicate the same functions.

  In FIG. 5, the heat exchange between the leeward side A1 and the leeward side B1 is achieved by the refrigerant flowing through the leeward side B1 of the flat tube 1 of the heat exchanger having a higher heat transfer performance to be transmitted to the air than the windward side A1. The dryness of the vessel outlet can be made equal. For this purpose, as shown in FIG. 4, the internal fins 11 are arranged in the refrigerant flow holes 9l and 9m through which the refrigerant of the flat tube 1 flows, and the number of the internal fins 11 is set on the leeward side B from the upstream side A1. By increasing the number of internal fins 11 so that 9 l (for example, 2) <9 m (for example, 5), only the outlet of the heat exchanger on the windward side A1 does not become extremely dry, It becomes possible to efficiently exchange heat between the air and the refrigerant, and the heat exchanger performance can be maximized.

Therefore, normally, the air flowing in from the leeward side A and the leeward side A1 of the heat exchanger first exchange heat, and then exchange heat with the leeward side B1 of the heat exchanger. Since the heat exchange is performed in a state where the temperature difference is small, the amount of heat exchange is larger on the windward side A1, and the windward side A1 has a higher degree of dryness at the outlet of the heat exchanger. Although the performance of the heat exchanger on the leeward side B1 cannot be sufficiently extracted, the configuration of the fourth embodiment improves the heat transfer performance on the refrigerant side of the leeward side B1, so that the entire heat exchanger is well-balanced. It is possible to exchange heat with the side.

(Embodiment 5)
FIG. 6 is a cross-sectional view of the parallel flow heat exchanger according to the fifth embodiment of the present invention as viewed from the direction of arrow B in FIG. The contents and principles that are the same as those in the above embodiment are omitted, and the same numbers are used in the following description to indicate the same functions.

  In FIG. 6, the heat exchanger of the windward side A1 and the leeward side B1 is gradually improved from the windward side A1 to the leeward side B1 of the heat exchanger by gradually improving the heat transfer performance that the refrigerant in the flat tube 1 transmits to the air. The dryness of the outlet can be made equal. For this purpose, as shown in FIG. 5, the internal fins 11 are arranged in the refrigerant flow holes 9n to 9s through which the refrigerant in the flat tube flows, and the number of the internal fins 11 is gradually increased from the upstream side A1 to the leeward side B. By arranging the number of internal fins 11 such that 9n (for example, 1) <9o (for example, 2) <9p (for example, 3) <9q (for example, 5) <9r (for example, 12) <9s (for example, 24) Only the outlet of the heat exchanger on the windward side A1 can be efficiently exchanged heat between the air and the refrigerant without extremely increasing the dryness, and the heat exchanger performance can be maximized.

  Therefore, normally, the air flowing in from the leeward side A and the leeward side A1 of the heat exchanger first exchange heat, and then exchange heat with the leeward side B1 of the heat exchanger. Since the heat exchange is performed in a state where the temperature difference is small, the amount of heat exchange is larger on the windward side A1, and the windward side A1 has a higher degree of dryness at the outlet of the heat exchanger. Although the heat exchanger performance of the leeward side B1 cannot be sufficiently extracted, the configuration of the fifth embodiment gradually improves the heat transfer performance on the refrigerant side from the leeward side A1 to the leeward side B1, so that the balance is good. The entire heat exchanger can exchange heat with the air side. In the above embodiment, the heat transfer amount is adjusted by installing the internal fins 11, but changing the height and position of the internal fins 11 and the shape of the internal fins has the same meaning.

  In addition, by optimizing the internal fins 11 as shown in the above-described Embodiments 3 to 5, the temperature of the evaporator accompanying the performance deterioration of the heat exchanger is reduced even during a heating operation at a low outside temperature where frost formation occurs. Due to the decrease, frost is not concentrated and clogged, and optimization of refrigerant circulation makes it easy for frost to adhere uniformly to the entire heat exchanger regardless of windward or leeward. It becomes possible to continue heating operation over time. In the above configuration, the same effect can be obtained even in the serpentine type heat exchanger, and the configuration is applicable regardless of the orientation, shape, top and bottom, and horizontal direction of the flat tubes and headers of the heat exchanger. Including.

  As described above, the windward side and the leeward side of the heat exchanger according to the present invention are effectively used for heat exchange, and further, it is possible to maximize the heat exchange performance without requiring a complicated configuration. It can also be applied to heat exchangers such as heat pump air conditioners and car air conditioners.

The partial perspective view of the heat exchanger concerning Embodiment 1 of the present invention. Sectional drawing of the heat exchanger concerning Embodiment 1 of this invention seen from the direction of arrow A of FIG. The partial expanded cross-sectional view which showed a part of heat exchanger in Embodiment 2 of this invention, and was seen from the arrow B direction in FIG. The partial expanded cross-sectional view which showed a part of heat exchanger in Embodiment 3 of this invention, and was seen from the arrow B direction in FIG. The partial expanded cross-sectional view which showed a part of heat exchanger in Embodiment 4 of this invention, and was seen from the arrow B direction in FIG. The partial expanded cross-sectional view which showed a part of heat exchanger in Embodiment 5 of this invention, and was seen from the arrow B direction in FIG. Overall perspective view of a conventional flat tube heat exchanger

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat tube 2 Fin 3 Header 4 Header 5, 6 Connection pipe 7, 8 Header 9, 9a-9s Refrigerant flow hole 10 Louver 11 Internal fin

Claims (5)

A pair of headers extending at a predetermined distance, a flat tube in which a refrigerant flows between the pair of headers, in which a refrigerant circulation hole is formed, and the flat tube are substantially perpendicular to and in close contact with each other. A plurality of plate fins arranged at the same pitch, and a heat exchanger having a structure in which the flat tube penetrates the plate fin, wherein the flow path of the flat tube is a low performance type on the windward side, and on the leeward side A heat exchanger characterized by a high-performance shape. A pair of headers extending at a predetermined distance, a flat tube in which a plurality of refrigerant flow holes are formed between the pair of headers, and a refrigerant pipe through which the refrigerant flows. A plurality of plate fins arranged at the same pitch, and a heat exchanger having a structure in which the flat tube penetrates the plate fin, and the flow path of the flat tube is gradually low performance type from the windward side to the downstream side A heat exchanger characterized by a high-performance shape. The heat exchanger according to claim 1, wherein fins are provided only inside the refrigerant flow hole on the leeward side of the flat tube. The heat exchanger according to claim 1, wherein more fins are provided in the refrigerant flow hole on the leeward side of the flat tube than on the windward side. The heat exchanger according to claim 2, wherein a large number of fins are gradually provided in the refrigerant circulation hole from the windward side to the leeward side of the flat tube.

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