JP2010249343A - Fin tube type heat exchanger and air conditioner using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fin tube type heat exchanger with high manufacturability, reducing draft resistance, improving a heat exchange amount, and reducing cost. <P>SOLUTION: The fin tube type heat exchanger is equipped with two main heat exchangers 4, 5 composed of plate fins 1 plurally disposed in parallel with each other and passing air between them, and a plurality of heat transfer tubes inserted into each plate fin perpendicularly in an air flowing direction and passing a working refrigerant through interiors. The heat transfer tubes of the two main heat exchangers are flat tubes 2, a passage cross-sectional area of one front face main heat exchanger 4 disposed in a front face side in a casing 10 is provided smaller than a passage cross-sectional area of one back face heat exchanger 5 disposed in a back face side in the casing, and step direction distances between the flat tubes are reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a finned tube heat exchanger for performing heat exchange between a refrigerant and a fluid such as a gas, and an air conditioner using the same.

A conventional fin tube type heat exchanger is configured using a flat tube as a front main heat exchanger and a circular tube as a back main heat exchanger.
And, by using a flat tube for the front main heat exchanger before the reheat valve, performance is improved, and by using a circular tube for the back main heat exchanger after the reheat valve, aiming for a decrease in the number of distribution (See Patent Document 1).

Japanese Patent Laying-Open No. 2008-261517 (first page, FIG. 1)

In the conventional fin tube type heat exchanger described in Patent Document 1, the use of a circular tube for the rear heat exchanger has a problem that the heat transfer performance is smaller than that of the front heat exchanger and the ventilation resistance is increased. there were.
In addition, a distributor is used for refrigerant distribution in the front heat exchanger, and there is a problem that pressure loss is large, a large structural space is required, and cost is high.

  The present invention has been made in order to solve the above-described problems. The fin tube type is capable of reducing ventilation resistance and improving the amount of heat exchange, and has high manufacturability and cost reduction. It aims at obtaining a heat exchanger and an air conditioner using the same.

  The finned tube heat exchanger according to the present invention is arranged in parallel with a plurality of plate-like fins through which air flows, and is inserted into each plate-like fin at a right angle in the air flow direction, and the working refrigerant passes through the inside. And a fin provided with two main heat exchangers that are provided in a plurality of stages in a step direction perpendicular to the gas passage direction and that are provided in a plurality of heat transfer tubes in two rows in the row direction of the gas passage direction. A tube type heat exchanger, wherein the heat transfer tubes of the two main heat exchangers are flat tubes, and the flow path cross-sectional area of one front main heat exchanger disposed on the front side in the casing It is made smaller than the channel cross-sectional area of the other back surface heat exchanger arranged on the back side of the tube, and the stepwise distance between the flat tubes is made small.

  In the finned tube heat exchanger according to the present invention, the heat transfer tubes of the two main heat exchangers are flat tubes, and the cross-sectional area of one front main heat exchanger arranged on the front side in the casing is The front main heat exchanger has a heat transfer area in the pipe that is smaller than the flow path cross-sectional area of another back heat exchanger disposed on the back side in the casing and the stepwise distance between the flat tubes is reduced. The heat exchanger performance can be greatly increased, and the back heat exchanger can increase the cross-sectional area in the flat tube, reduce the number of refrigerant paths, reduce pressure loss, reduce ventilation resistance, and heat exchange There is an effect that the ability can be improved.

The cross-sectional view which shows the indoor unit of the air conditioner using the fin tube type heat exchanger of embodiment of this invention. The block diagram which shows the refrigerant | coolant flow path at the time of using the fin tube type heat exchanger as an evaporator. The cross-sectional view which shows the piping structure of the side where the header of the fin tube type heat exchanger is not attached. The partial side view and top view which show the structure of the header of the fin tube type heat exchanger, and the main heat exchanger. The perspective view and sectional drawing which show the circular tube-flat tube joint used for the fin tube type heat exchanger. The side view which shows the U bend and 3 way pipe which are used for the same fin tube type heat exchanger. Sectional drawing which shows the flat tube used for the front main heat exchanger of the fin tube type heat exchanger. Sectional drawing which shows the flat tube used for the back main heat exchanger of the fin tube type heat exchanger. The refrigerant circuit figure of the refrigerating cycle of the air conditioner using the fin tube type heat exchanger.

FIG. 1 is a cross-sectional view showing an indoor unit of an air conditioner using a finned tube heat exchanger according to an embodiment of the present invention.
The indoor unit of the air conditioner of this embodiment includes a blower 9 in a casing 10 and a finned tube heat exchanger 100 disposed so as to surround the blower 9.
A suction port (not shown) is provided on the upper side of the casing 10, and the air sucked from the suction port passes through the finned tube heat exchanger 100 and the blower 9 and is provided on the lower side of the casing 10. From the air outlet 10a, the air is blown out forward in the lower part.
11 is a front panel provided in front of the casing 10, 12 is a top grill provided above the casing 10, 13 is an automatic cleaning mechanism provided in the front panel 11, and 23 is provided in the front panel 11. It is a filter.

  The finned tube heat exchanger 100 is inserted perpendicular to the laminated plate-like fins 1 and the plate-like fins 1 so that a differential refrigerant (hereinafter referred to as refrigerant) passes through the fin-tube type heat exchanger 100 with respect to the gas passage direction. A main heat exchanger using a flat tube 2 as a heat transfer tube, which has a structure including a plurality of heat transfer tubes provided in a plurality of rows in a row direction that is a perpendicular direction and in a row direction that is a gas passage direction. 4a, 4b, 5a, 5b, and auxiliary heat exchangers 6, 7, 8 using a circular tube 3 as a heat transfer tube.

Of the main heat exchangers 4a, 4b, 5a, and 5b, the front main heat exchangers 4a and 4b disposed on the upper and lower portions of the front surface of the casing 10 have a fin 1 in a square shape in the step direction. And divided into two in the column direction. Of the main heat exchangers 4a, 4b, 5a and 5b, the back main heat exchangers 5a and 5b disposed on the back of the casing 10 are also divided into two parts, with the upper part being forward and the lower part being slightly rearward. It is arranged at an angle.
The auxiliary heat exchangers 6 and 7 are arranged in the first row of the front main heat exchangers 4a and 4b in the air flow direction, and the auxiliary heat exchanger is arranged in the first row of the rear main heat exchangers 5a and 5b in the air flow direction. 8 is disposed.

Next, the main heat exchangers arranged in the second and third rows in the air flow direction will be described.
The front main heat exchangers 4a and 4b arranged on the front panel side have a pitch Fp in the stacking direction of the fins 1 of Fp = 0.0011m, a fin thickness Ft = 0.0001m, and a fin width in the air flow direction. Is L = 0.137m, and the distance Dp of the flat tubes which are adjacent heat transfer tubes in the stage direction of the heat exchanger is Dp = 0.0095 m.
The back main heat exchangers 5a and 5b arranged on the back side have Fp = 0.0012m, fin thickness Ft = 0.0001m, and the fin width in the air flow direction is L = 0.127m, heat exchange. The distance Dp between the flat tubes which are adjacent heat transfer tubes in the stage direction of the vessel is Dp = 0.014 m.
The fin collar and the flat tube, which is the heat transfer tube, are completely joined by brazing.
In the main heat exchangers 4a, 4b, 5a and 5b, the flat tubes 2 are arranged in a staggered manner, and the fins 1 are divided for each row. The number of columns is two.

  In the auxiliary heat exchangers 6, 7, and 8 using circular tubes, the pitch Fp in the stacking direction of the fins 1 is Fp = 0.0014m, the fin thickness Ft = 0.0001m, and the fin width in the air flow direction is L = 0.0127m, the distance Dp of the circular tubes that are heat transfer tubes adjacent in the stage direction of the heat exchanger is Dp = 0.0204m, and the fin collar and the circular tube that is the heat transfer tube are mechanically expanded to the fin front edge. Are pressure bonded.

  In the fin-tube heat exchanger configured as described above, the flat tube 2 and the circular tube 3 are formed of an aluminum alloy extruded shape, and the plate-like fins 1 are formed of an aluminum alloy plate. Thus, by making all the heat exchangers the same material, the proof stress of corrosion improves.

Moreover, in the main heat exchangers 4a, 4b, 5a, and 5b, by arranging the flat tubes 2 in a staggered manner, the heat transfer coefficient of the flat tube leading edge is improved, and the heat exchanger performance is improved.
Further, by dividing the fins 1 in the second and third rows in the main heat exchangers 4a, 4b, 5a and 5b, the arrangement of the heat exchangers can be variously accommodated in the indoor unit box. An improvement in heat transfer coefficient due to the leading edge effect (air boundary layer separation effect) on the fins can also be expected.

Further, among the main heat exchangers 4a, 4b, 5a and 5b, the fins 1 of the front main heat exchangers 4a and 4b are integrally formed in a square shape in the step direction and divided in the row direction. Thus, air escape between the main heat exchangers can be prevented, and the heat exchange capacity can be increased.
In particular, since the flat tube interval of the bent portion 22 is increased due to the shape of the flat tube 2, the space between the bent portions 22 is filled with the fin 1, and the fin 1 is integrated with the auxiliary heat exchangers 6 and 7 using the circular tube 3. The effect is increased. Moreover, since there is no seam in the fin 1, it is possible to prevent dew dripping when used as an evaporator.

  Further, in the main heat exchangers 4a, 4b, 5a, and 5b, the flatness at the position overlapping the front main heat exchanger 4b in the downstream side of the air flow at the top of the front main heat exchanger 4a in the upstream side of the air flow. Since the number of pipes has triangular fins 21 in which the flat tubes 2 are not disposed, the structural compactness and the air flow are guided in the direction of gravity, and the front heat exchange on the leeward side is smoothly performed. The wind speed at the uppermost part of the front heat exchanger 4b on the leeward side can be prevented from being excessively induced by the heat exchanger 4b.

FIG. 2 is a configuration diagram showing a refrigerant flow path when the finned tube heat exchanger according to the present embodiment is used as an evaporator.
When used as an evaporator during cooling, the refrigerant passes through the auxiliary heat exchangers 8, 7, 6 in one pass and reaches the windward front heat exchanger 4 a, and the front heat exchanger 4 a has a round shape. The upstream header 14 is distributed for each number of flat tube stages, passes through the U-bend 17 on the side where no header is attached, and reaches the leeward front heat exchanger 4b. In the front heat exchanger 4b, After being joined by the downstream header 15, it passes through the expansion device (reheat valve) 19, passes through the bifurcated branch pipe 20, and is then branched into two by the three-way pipe 18 attached to the main heat exchanger 5 a on the back side. After that, the three-way pipe 18 attached to the main heat exchanger 5b joins and flows out.

FIG. 3 is a cross-sectional view showing a piping configuration on the side where the header of the finned tube heat exchanger of the present embodiment is not attached.
On the side of the fin tube type heat exchanger 100 where the header is not attached, the piping is composed of a flat tube-circular tube joint 16 and a U bend 17.
In this way, in the heat exchanger in which the number of stages = the number of passes, such as the front main heat exchangers 4a and 4b, the side having the mechanism for distributing the refrigerant is the upstream and downstream headers 14 and 15 and the flat tube − Constructed with the circular pipe joint 16 and the side without the refrigerant distribution mechanism with the flat pipe-circular pipe joint 16 and the U-bend 17 makes it more compact and simpler than the case of using a distributor. Can be realized. Further, it is not necessary to perform refrigerant redistribution on the side that does not have a mechanism for distributing the refrigerant, and the heat exchange characteristics are stabilized.

In addition, if the distribution of the rear heat exchangers 5a and 5b becomes uneven at the outlet of the evaporator having a large refrigerant dryness, the refrigerant is overheated and the heat exchanger performance is greatly reduced. However, the front heat exchange before the reheat valve is performed. By increasing the number of passes of the units 4a and 4b, distributing the header, and reducing the number of passes of the rear heat exchangers 5a and 5b after the reheat valve, the dryness of the refrigerant (= vapor mass flow rate / vapor + liquid mass) The stability of the distribution performance after the reheat valve having a large flow rate) can be maintained.
In the main heat exchanger 4b before the reheat valve, even when the dryness of the refrigerant is small and the distribution performance is low, the refrigerant is not easily overheated, and the heat exchanger performance is sufficiently maintained even when the multi-pass distribution is performed by the header, and is compact. Cost reduction can be achieved.

FIG. 4 shows the configuration of the header and main heat exchanger of the finned tube heat exchanger of the present embodiment, where (a) is a partial side view, (b) is a plan view, and FIG. 5 is a fin of the present embodiment. The circular tube-flat tube joint used for the tube type heat exchanger 100 is shown, (a) is a perspective view, (b) is sectional drawing.
The header 14 and the flat tube 2 of the front main heat exchanger 4 a are joined by a circular tube-flat tube joint 16. Since a circular tube is inserted into the header 14, the header diameter can be set smaller than the long axis length of the flat tube 2, and compactness is possible.
The circular tube-flat tube joint 16 is manufactured by inserting a flat jig into the circular tube and performing plastic processing. By using this circular tube-flat tube joint 16, the versatility of the refrigerant flow path configuration is dramatically improved, such as free passage of the heat exchanger, as compared to securing the refrigerant flow path by the header in the air conditioner. It becomes possible.

FIG. 6 is a side view of a U-bend and a three-way pipe used in the finned tube heat exchanger of the present embodiment.
The cross section of the pipe end of the U-bend 17 that connects between the flat tubes 2 and the three-way pipe 18 that bifurcates the refrigerant flowing into the main heat exchanger is circular, and the circular tube-flat tube joint shown in FIG. It joins with the 16 circular pipe cross section side.
In addition, the three-way pipe 18 connects the circular pipe-flat pipe joint 16 and a bulge portion that is a pipe connecting the branch pipe, but since the outlet pipe end is circular, the refrigerant flow path can be freely connected. The degree improves dramatically.
Further, since the U-bend 17 has a circular cross section at the end of the pipe, it is possible to connect the pipes obliquely on the front main heat exchangers 4a and 4b on the side where no header is attached.

  FIG. 7 is a cross-sectional view showing the flat tube 2 used for the front main heat exchangers 4a and 4b among the main heat exchangers. The flat tube 2 has a short axis length of 0.0022 m and a long axis of 0.0105 m, and the inside of the flat tube 2 is branched into eight flow paths by partition walls.

  FIGS. 8A and 8B are cross-sectional views showing the flat tube 2 used in the rear heat exchangers 5a and 5b in the main heat exchanger. The flat tube 2 has a short axis length of 0.0038 m and a long axis of 0.0105 m, and the inside of the flat tube 2 is branched into five flow paths by partition walls. By attaching a plurality of grooves 30 in the tube of the flat tube 2 as shown in FIG. 8B, the heat transfer area between the refrigerant and the tube wall can be increased, and the heat exchange capability can be further improved.

When the finned tube heat exchanger 100 of the present embodiment is used as an evaporator, as shown in FIG. 1, in the front main heat exchangers 4a and 4b in the portion where the refrigerant dryness before the reheat valve is small, By reducing the area and reducing the distance between the flat tubes, the heat transfer area in the tube can be greatly increased and the performance of the heat exchanger can be improved, while the pressure loss in the tube is increased and the number of refrigerant paths is increased.
However, as described above, even when the refrigerant has a low dryness and the distribution performance is low, even if the distribution performance by the header is deteriorated because the refrigerant is not easily overheated, the heat exchanger capability can be improved.
Further, in the rear heat exchangers 5a and 5b where the refrigerant dryness after the reheat valve is large, as shown in FIG. 1, the cross-sectional area in the flat tube is made larger than that of the front main heat exchangers 4a and 4b, and the refrigerant path The number can be reduced, and the pressure loss can be reduced and the heat exchange capacity can be improved.

FIG. 9 is a refrigerant circuit diagram of a refrigeration cycle of an air conditioner using the finned tube heat exchanger of the present embodiment. The refrigerant circuit shown in FIG. 9 includes a compressor 33, a condensation heat exchanger 34, an expansion device 35, an evaporating heat exchanger 36, and a blower 37.
By using the finned tube heat exchanger 100 according to the above embodiment for the condensation heat exchanger 34, the evaporating heat exchanger 36, or both, an air conditioner with high energy efficiency can be realized.
Here, energy efficiency is constituted by the following equation.
Heating energy efficiency = indoor heat exchanger (condenser) capacity / total input Cooling energy efficiency = indoor heat exchanger (evaporator) capacity / total input

In addition, about the fin tube type heat exchanger described in the said embodiment, and an air conditioner using the same, HCFC (R22) and HFC (R116, R125, R134a, R14, R143a, R152a, R227ea, R23, R236ea , R236fa, R245ca, R245fa, R32, R41, RC318, etc., and some mixed refrigerants R407A, R407B, R407C, R407D, R407E, R410A, R410B, R404A, R507A, R508A, R508B, etc.), HC , Isobutane, ethane, propane, propylene, etc. and some mixed refrigerants of these refrigerants), natural refrigerants (air, carbon dioxide, ammonia, etc., some mixed refrigerants of these refrigerants), and some mixtures of these refrigerants Any kind of refrigerant Be used refrigerant, it can achieve its effect.
Moreover, although the example of air and a refrigerant | coolant was shown as a working fluid, even if it uses other gas, liquid, and gas-liquid mixed fluid, there exists the same effect.

In addition, heat transfer tubes and fins often use different materials, but using the same material, such as copper for heat transfer tubes and fins, and aluminum for heat transfer tubes and fins, it is possible to braze the fins and heat transfer tubes. Thus, the contact heat transfer coefficient between the fin portion and the heat transfer tube is dramatically improved, and the heat exchange capability is greatly improved. Moreover, recyclability can also be improved.
In addition, when brazing in a furnace as a method for bringing the heat transfer tube and fin into close contact with each other, the hydrophilic material is burned off during brazing in the pretreatment by performing post-treatment to apply a hydrophilic material to the fin. Can be prevented.

  In addition, the heat exchanger described in the above embodiment and the air conditioner using the heat exchanger are insoluble, such as mineral oil, alkylbenzene oil, ester oil, ether oil, fluorine oil, etc. Regardless, any refrigeration oil can achieve its effect.

  DESCRIPTION OF SYMBOLS 1 Plate-shaped fin, 2 flat tube, 3 circular tube, 4a, b front main heat exchanger, 5a, b back main heat exchanger, 6, 7, 8 auxiliary heat exchanger, 9 blower, 10 casing, 10a blower outlet 11 Front panel, 12 Top grille, 14 Upstream header, 15 Downstream header, 16 Round tube-flat tube joint, 17 U bend, 18 3-way tube, 19 Reheat valve, 20 Branch tube, 21 Triangular fin Part, 22 bending part, 24 air flow direction, 25 air flow direction, 100 fin tube type heat exchanger.

Claims (9)

A plurality of plate fins arranged in parallel and through which air flows, and inserted into each of the plate fins at a right angle in the air flow direction, the working refrigerant passes through the inside, and a step perpendicular to the gas passage direction. A fin tube type heat exchanger comprising two main heat exchangers, each of which is provided with a plurality of stages in the direction and a plurality of heat transfer tubes provided in two rows in the row direction of the gas passage direction,
The heat transfer tubes of the two main heat exchangers are flat tubes, and the flow path cross-sectional area of one front main heat exchanger arranged on the front side in the casing is arranged on the back side in the casing. A finned tube heat exchanger characterized in that it is smaller than the cross-sectional area of the two rear heat exchangers and the stepwise distance between the flat tubes is reduced.   A header is attached to one end of the front heat exchanger, refrigerant distribution is performed inside the header, and the other end on the opposite side uses a U-bend to form a refrigerant flow path. The fin tube type heat exchanger according to claim 1, wherein refrigerant distribution is performed by a branch pipe that divides a three-way pipe and one flow path into two flow paths.   3. The finned tube heat exchanger according to claim 1, wherein the flat tubes of the two main heat exchangers are arranged in a staggered manner.   The fin tube type heat exchanger according to any one of claims 1 to 3, wherein the fins of the front main heat exchanger are integrally formed in a square shape in a step direction and divided in a row direction.   Among the front heat exchangers, at the uppermost part of the front heat exchanger in the air flow upstream row, the portion corresponding to several flat tubes in the position overlapping the front heat exchanger in the air flow downstream row in the step direction is a flat tube. The finned tube heat exchanger according to any one of claims 1 to 4, further comprising triangular fins that are not arranged.   6. The finned tube heat exchanger according to claim 1, wherein in the front main heat exchanger, the header and the flat tube are joined using a circular-flat tube joint. .   The fin tube type heat exchanger according to claim 6, wherein a header diameter of the circular-flat tube joint is smaller than a long axis length of the flat tube.   The finned tube heat according to any one of claims 1 to 7, wherein an auxiliary heat exchanger having a circular heat transfer tube is provided upstream of the two main heat exchangers in the gas passage direction. Exchanger.   An air conditioner in which the finned tube heat exchanger according to any one of claims 1 to 8 is disposed in a casing provided with an inlet and an outlet.

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