JP2007255842A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of simplifying a refrigerant flow channel and a throttle, improving productivity, and significantly reducing costs. <P>SOLUTION: In this air conditioner, heat transfer tubes of an indoor heat exchanger are formed as one flow channel by being arranged in series over the whole length, at least two or more kinds of heat transfer tubes are used so that the heat transfer tube at a refrigerant inlet side has an inner diameter B, and the heat transfer tube at a downstream side has an inner diameter C, and the relationship among the inner diameters of the heat transfer tubes satisfies A≥C>B, when a heat transfer tube of an outdoor heat exchanger has an inner diameter A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner including an indoor heat exchanger that is formed in one refrigerant flow path and uses two or more types of heat transfer tubes having different inner diameters.

  In a heat exchanger of a refrigeration cycle incorporated in an air conditioner, a plurality of heat transfer tubes are heat-transferred so as to form a row of tubes on a large number of heat transfer fins.

  As shown in FIG. 8, in the conventional indoor heat exchanger 21, the heat transfer tubes 22 all have an inner diameter of 6.35 mm, and are divided using the flow dividing tube 23 and the connecting tube 24, so that the refrigerant flow is divided into two flow paths. Yes.

  In this way, according to the refrigerant circulation amount (capacity rank of the air conditioner), the refrigerant pressure loss and the heat transfer amount in the pipe are balanced using a shunt pipe or the like, and the refrigerant flow path (number of passes) is selected. The total heat exchange amount was optimized. Therefore, the flow path becomes complicated, and the amount of restriction needs to be controlled according to the amount of circulation. Especially in the case of a bending type heat exchanger, the number of connecting pipes is also complicated and the manufacturability is poor. There was a problem of increased costs.

Patent Document 1 discloses that the heat transfer tube diameter of the single-phase flow region is smaller than the heat transfer tube diameter of the two-phase flow region, and heat transfer in the single-phase flow region that flows as a single-phase flow is promoted. A heat exchanger has been proposed to improve the efficiency.
JP 2001-304791 A

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide an air conditioner in which the refrigerant flow path and the throttle are simplified, the productivity is improved, and the cost can be significantly reduced.

  In order to achieve the above-described object, an air conditioner according to the present invention includes a refrigeration cycle configured by sequentially connecting a compressor, a four-way switching valve, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger. In the air conditioner for both cooling and heating, the indoor heat exchanger has a heat transfer tube formed in one flow path over its entire length, and the inner diameter of the heat transfer tube on the refrigerant upstream side during cooling operation is B, and the heat transfer tube is on the downstream side. The heat pipe is composed of at least two types of heat transfer pipes having different inner diameters so that the inner diameter of the heat pipe is C, and when the inner diameter of the heat transfer pipe of the outdoor heat exchanger is A, the relationship between the inner diameters of the heat transfer pipes is A ≧ C > B.

  According to the air conditioner according to the present invention, it is possible to provide an air conditioner in which the refrigerant flow path and the throttle are simplified, the productivity is improved, and the cost can be significantly reduced.

  An air conditioner according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a conceptual diagram of a refrigeration cycle incorporated in an air conditioner according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a heat exchanger used in the refrigeration cycle.

  As shown in FIG. 1, the air conditioner according to the first embodiment is a split-type air conditioning unit, and a refrigeration cycle 1 is incorporated in a housing (not shown). The refrigeration cycle 1 includes a compressor 2. The four-way switching valve 3, the outdoor heat exchanger 4, the throttle mechanism 5, and the indoor heat exchanger 6 are sequentially connected by piping.

  As shown in FIG. 2, the indoor heat exchanger 6 is configured by bending a front heat exchanger 6A and a rear heat exchanger 6B into a reverse V shape in a side view, and a plurality of heat transfer tubes 7 are formed. The heat transfer fins 8 are inserted in heat transfer so as to form a tube row, and the heat transfer tubes 7 are formed in one flow path in series over the entire length thereof.

  The heat transfer tube 7 is on the refrigerant upstream (inlet) side during the cooling operation, the inner diameter of the basic heat transfer tube 7b occupying a length exceeding 2/3 of the total tube length of the indoor heat exchanger 6 is B, and the outlet (downstream) side When the inner diameter of the heat transfer tube of the outdoor heat exchanger 4 is A, the relationship between the inner diameters is as follows: A ≧ C> B To do.

  As a specific example, the inner diameter of the basic heat transfer tube 7b of the substantially C-shaped indoor heat exchanger 6 is set to 6.35 mm, and the inner diameter of the large-diameter heat transfer tube 7c in the rear row side tube row of the front side heat exchanger 6A is set to 7 mm. And the inner diameters of the heat transfer tubes of the outdoor heat exchanger 4 are all 8 mm. In addition, the large-diameter heat transfer tube 7c on the downstream side during the cooling operation is set to 1/3 or less of the total piping length (tube 7b + 7c) of the indoor heat exchanger 6.

  The heat transfer tubes 7 of the indoor heat exchanger 6 are arranged in two stages on the outside (upstream side of the air flow) and inside (downstream side of the air flow) of the heat transfer fins 8, respectively. In the refrigerant flow during the cooling operation, an inlet heat transfer tube 7b1 is provided on the outer upper portion of the rear heat exchanger 6B, and the outer pipes are sequentially connected from the inlet heat transfer tube 7b1 to the bottom in the lower direction. It connects with an inner heat exchanger tube in the lowest part, and after connecting an inner heat exchanger tube to the uppermost part sequentially in the upper direction, it connects with the heat exchanger tube 7b2 formed in the outermost upper part of the rear side heat exchanger 6B. Next, it connects with the heat exchanger tube 7b3 formed in the outermost upper part of 6 A of front side heat exchangers, connects the heat exchanger tube arranged on the outer side of the front side heat exchanger 6A to a lowermost part one by one, and also in the lowest part. And connected to the heat transfer tube 7b4 on the outlet side of the inner basic heat transfer tube 7b. Next, it connects with the heat transfer pipe 7c1 used as the inlet side of the large-diameter heat transfer pipe 7c formed in the inner lower part of the front heat exchanger 6A, and connects the inner heat transfer pipes in the upward direction in order, It consists of one serial flow path connected to the heat transfer tube 7c2.

  As shown in FIG. 3, after the heat transfer fins 8 in which the tube holes 8a are formed in two substantially straight lines are overlapped and assembled by inserting the U-shaped heat transfer tube 7, as shown in FIG. The U-shaped connecting pipe 7d that connects the heat transfer pipe 7b2 formed on the outermost uppermost part of the rear heat exchanger 6B and the heat transfer pipe 7b3 formed on the outermost uppermost part of the front heat exchanger 6A is shown in FIG. In the state of the cooler 6, it is brazed, bent as shown in FIG. 4 to the final shape as the heat exchanger 6, and further, as shown in FIG. 5, the indoor heat exchanger 6 has a refrigerant downstream in the cooling operation. An outlet-side U-shaped tube 9 having an inner diameter C is connected to the outlet-side heat transfer tube 7c2 on the side, an inlet-side U-shaped tube 10 having an inner diameter B is connected to the refrigerant inlet-side heat transfer tube 7b1, and a U-shaped tube having an inner diameter C on the outlet side is further connected. A compressor side pipe 12 is connected to 9 through an auxiliary outlet pipe 11 having an inner diameter D. Here, the relationship between the inner diameters C and D is C ≧ D.

  As described above, the indoor heat exchanger 6 is composed of two basic heat transfer tubes 7b and large-diameter heat transfer tubes 7c having different inner diameters, and the relationship between the inner diameter of the outdoor heat exchanger 4 and A ≧ C> B, Both the pressure loss and heat transfer coefficient in the heat exchangers 4 and 6 during the cooling operation and the heating operation can be set optimally, and the outdoor heat exchanger capacity 4 can be reduced by improving the efficiency of the indoor heat exchanger 6. Is possible.

  Further, by optimizing the internal volumes of the indoor heat exchanger 6 and the outdoor heat exchanger 4, the heat exchange amount of both the heat exchangers 4 and 6 can be balanced, so that the cooling operation and the heating operation can be performed. The throttle can be made constant, an electronic expansion valve with a variable throttle amount is not required, and a low-cost capillary tube with a constant throttle amount can be used, which is inexpensive.

  In particular, by arranging the large-diameter heat transfer tube on the downstream side, which is the gas region side of the refrigerant, the optimum throttle amount during the cooling cycle and heating cycle operation can be made substantially equal, and the use of the capillary is realized.

  As shown in FIGS. 6 and 7, generally, a refrigeration cycle including an indoor heat exchanger in which heat transfer tubes are branched in parallel and formed with two flow paths is used for both cooling and heating operations. Is large (around 3.6 kW) and maintains a high COP, which is suitable for an air conditioner having a large cooling and heating capacity, but the piping structure becomes complicated. On the other hand, in the refrigeration cycle in which the heat transfer tubes are arranged in series over the entire length without branching and the one-channel indoor heat exchanger is provided, the COP rapidly decreases as the cooling capacity increases during both the cooling operation and the heating operation. Therefore, it is not suitable for an air conditioner having a large cooling / heating capacity, but with a small capacity (2.2 kW), a COP exceeding the two-channel method is obtained, and it is suitable for an air conditioner that air-conditions a small room of 6 tatami or less.

  Therefore, in the present embodiment of one flow path suitable for a small capacity air conditioner, it is not necessary to connect a branch pipe necessary for two flow paths or use a movable part such as an electronic expansion valve. Reliability can be increased.

  In addition, since the outlet side U-shaped tube 9 with the inner diameter C and the compressor side piping 12 are connected using the auxiliary outlet tube 11 with the inner diameter D (C ≧ D), there is no need for flare processing for the pipe connection, and manufacturing And automatic brazing becomes easy.

  Further, the indoor heat exchanger is configured such that a front heat exchanger and a rear heat exchanger are bent in an inverted V shape when viewed from the side, and the heat transfer tubes 7 are arranged in two stages on the outer side and the inner side of the heat transfer fins 8. The arrangement of the heat transfer tubes of the indoor heat exchanger is such that an inlet is provided at the upper part of the outer side of the rear heat exchanger in the refrigerant flow during the cooling operation, and the outer side from the inlet side is sequentially connected in the downward direction. , Further connected to the inner side and sequentially connected to the uppermost part in the upper direction, then connected to the outer upper part of the front heat exchanger, sequentially connected to the lower direction, further connected to the inner side and sequentially connected to the upper direction, Piping connection is simplified by having a single series flow path with an outlet on the inner side of the front heat exchanger and a heat transfer tube with an inner diameter of C inside the front heat exchanger. In addition, a heat transfer tube having an inner diameter of C is disposed on the downstream side of the air flow of the front heat exchanger. In, can wind passing through the heat transfer tubes of the front heat exchanger is flowed efficiently.

  According to the air conditioner of the present embodiment, the refrigerant flow path and the throttle are simplified, the productivity is improved, and a significant cost reduction is realized.

  In this embodiment, the inner diameter of the U-shaped tube of the indoor heat exchanger has been described with two types of examples. However, the inner diameter of the tube is gradually increased toward the downstream side (gas side) of the refrigerant. Three or more types of inner diameters may be used.

The conceptual diagram of the refrigerating cycle integrated in the air conditioner which concerns on this invention. The longitudinal cross-sectional view of the indoor heat exchanger integrated in the air conditioner which concerns on this invention. The side view at the time of manufacture of the indoor heat exchanger shown in FIG. The side view at the time of manufacture of the indoor heat exchanger shown in FIG. The side view at the time of use of the indoor heat exchanger shown in FIG. The related figure of the refrigerant | coolant flow path number at the time of air_conditionaing | cooling operation of a general air conditioner, and COP. The related figure of the number of refrigerant channels at the time of heating operation of a general air conditioner, and COP. The longitudinal cross-sectional view of the indoor heat exchanger integrated in the conventional air conditioner.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Refrigeration cycle, 2 ... Compressor, 3 ... Four-way selector valve, 4 ... Outdoor heat exchanger, 5 ... Throttle mechanism, 6 ... Indoor heat exchanger, 6A ... Front side heat exchanger, 6B ... Rear side heat exchanger, 7 ... Heat transfer tube, 7b ... Basic heat transfer tube, 7c ... Large diameter heat transfer tube, 7d ... Connection tube, 8 ... Heat transfer fin, 9, 10 ... U-shaped tube, 11 ... Auxiliary outlet tube, 12 ... Compressor side piping.

Claims (3)

In an air conditioner combined with a refrigeration cycle configured by sequentially connecting a compressor, a four-way switching valve, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger, the indoor heat exchanger includes a heat transfer tube. Two or more types of heat transfer pipes that are formed in one flow path over the entire length and that have at least two different inner diameters so that the inner diameter of the heat transfer tube upstream of the refrigerant during cooling operation is B and the inner diameter of the heat transfer tube downstream is C. An air conditioner characterized in that the relationship between the inner diameters of the heat transfer tubes is A ≧ C> B, where A is the inner diameter of the heat transfer tubes of the outdoor heat exchanger. The A is 8 mm, B is 6.35 mm, C is 7 mm, and the heat transfer tube having an inner diameter C that is the downstream side during the cooling operation of the indoor heat exchanger is 1/3 or less of the total pipe length of the indoor heat exchanger. The air conditioner according to claim 1, wherein The indoor heat exchanger is configured by bending a front heat exchanger and a rear heat exchanger in a reverse V shape when viewed from the side, and heat transfer tubes are arranged in two stages on the outside and inside of the heat transfer fins, The arrangement of the heat transfer tubes of the indoor heat exchanger is such that, in the refrigerant flow during the cooling operation, an inlet portion is provided on the outer upper portion of the rear heat exchanger, and the outer side is sequentially connected from the inlet side to the lower side, and further to the inner side. After connecting and sequentially connecting up to the top in the upper direction, connecting to the outer upper part of the front heat exchanger and connecting to the lower direction sequentially, further connecting to the inner side and sequentially connecting to the upper direction, the front heat exchanger The air conditioner according to claim 1, wherein the air conditioner is configured by a single series flow path having an outlet portion at an inner upper portion, and a heat transfer tube having an inner diameter of C is formed inside the front heat exchanger. Machine.

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