JP6469245B2 - Air heat exchanger and outdoor unit - Google Patents

Description

  The present invention relates to an air heat exchanger and an outdoor unit, and more particularly to a structure of an air heat exchanger used for a large outdoor unit.

  For example, in a cold / hot water supply system employed in a building such as an office building, an air conditioner is provided as a heat load source in each room, and cold / hot water generated by the cold / hot heat source machine is supplied. The cold / hot heat source machine exchanges heat with the outside air by an air heat exchanger of a heat pump refrigeration cycle to generate cold water or hot water. As an example of the cold / hot water supply system, Patent Literature 1 discloses a technique for generating cold / hot water and performing air conditioning in the facility and adjusting the water temperature of the pool using the cold / hot water.

  Generally, the fins used in the air heat exchanger are provided with a cut and raised, and the heat exchange efficiency is improved by causing a turbulent flow. For example, as disclosed in Patent Document 2, it has been proposed to improve drainage by unevenness formed on the fins, and to suppress an increase in blowing resistance due to the condensed water that has adhered.

JP 2002-13838 A JP 54-153366 A

  When the cold / hot water supply system of Patent Document 1 is adopted in a building such as an office building, since the outdoor unit is installed in a narrow space such as a rooftop, the air heat exchanger accommodated in the outdoor unit is bent to be small. It is necessary to make it. However, when the air heat exchanger is bent, the fins disposed inside the bends are close to each other, so that there is a limit to the angle at which the air heat exchanger can be bent. This is because when the fins are close to each other, the cut and raised portions provided on the fins fall down or come into contact with each other, leading to an increase in blowing resistance. Since the increase in airflow resistance increases the power consumption of the fan, the energy efficiency of the chilled / hot water supply system used in office buildings where measures are taken to improve energy efficiency while suppressing the capacity of the compressor is relatively low. Will be reduced.

  In the case where a fin with unevenness as in Patent Document 2 is adopted, it is conceivable that stress concentration occurs in the fin due to bending, and the strength of the fin decreases. As a result, the fin bends in an unintended direction, the gap between the fins is blocked, and the blowing resistance increases.

  The present invention has been made to solve the above-described problems, and provides an air heat exchanger and an outdoor unit in which the strength of the fin is maintained even when the size is reduced and the blowing resistance is reduced. With the goal.

An air heat exchanger according to the present invention includes a plurality of first fins, a plurality of first heat exchangers each including a plurality of rough fins, a heat transfer tube that is inserted through the plurality of rough fins and through which a refrigerant flows, and a plurality of smooth fins . A plurality of rough surface fins , and a second heat that is inserted through the plurality of smooth fins and the plurality of rough surface fins and includes a heat transfer tube through which the refrigerant flows, and is adjacent to the plurality of first heat exchangers. The first heat exchanger is bent toward the second heat exchanger, the second heat exchanger is bent toward the same side as the first heat exchanger, and the first heat exchanger is bent toward the second heat exchanger. In the heat exchanger , only the rough surface fins are provided, and in the bent region of the second heat exchanger, the smooth fins are provided, and the second heat exchanger is bent. The rough surface fins are provided in the regions that are not .

  According to the air heat exchanger according to the present invention, the first heat exchanger and the second heat exchanger are bent toward the second heat exchanger provided with the smooth fins, and therefore stress is concentrated at the bent portion. There is no contact between the adjacent smooth fins due to sudden bending. For this reason, even if the air heat exchanger is downsized, the strength of the fins can be prevented from being lowered and the power consumption of the fan can be reduced. Moreover, since the 1st heat exchanger is provided with the rough surface fin in which the unevenness | corrugation was formed, the efficiency of heat exchange can be maintained favorable.

It is a figure which shows the refrigerating-cycle apparatus which the outdoor unit which concerns on this Embodiment accommodates. It is a schematic top view of the air heat exchanger of the outdoor unit of FIG. It is the expanded side view which looked at the air heat exchanger of FIG. 2 and the air heat exchanger of FIG. 2 from the direction shown by the arrow. It is the expanded side view which looked at the air heat exchanger of FIG. 2 and the air heat exchanger of FIG. 2 from the direction shown by the arrow. It is the expanded side view which looked at the linear part of the heat exchanger which concerns on a modification from the direction of the arrow. It is the expanded side view which looked at the bending part of the heat exchanger which concerns on a modification from the direction of the arrow. It is a scatter diagram which shows the result of the performance evaluation of the air heat exchanger which concerns on this Embodiment.

Embodiment.
FIG. 1 is a diagram showing a refrigeration cycle apparatus housed in an outdoor unit 100 according to the present embodiment. As shown in FIG. 1, an outdoor unit 100 includes a refrigeration cycle apparatus in which a compressor 1, an air heat exchanger 2, an expansion valve 4, and an evaporator 5 are connected by a refrigerant pipe 7. It is housed in a casing 8 having a shape. The air heat exchanger 2 is disposed at the top of the housing 8 together with the fan 3. The outdoor unit 100 is in the form of a top flow type, and is installed, for example, on the roof of a building.

  The air heat exchanger 2 is disposed inside the housing 8 along the inner surface of the housing 8, and performs heat exchange between the refrigerant flowing through the inside and the air passing therethrough. The fan 3 sucks air from the side surface of the housing 8 and blows air from above while passing through the air heat exchanger 2. The evaporator 5 constitutes a cold / hot heat source machine, and the refrigerant heat exchanged in the air heat exchanger 2 flows in and flows through the inlet water pipe 6a and the outlet water pipe 6b arranged close to the evaporator 5. Exchange heat with water. The water flowing through the inlet water pipe 6a and the outlet water pipe 6b becomes cold / hot water by heat exchange and circulates in the facility.

  FIG. 2 is a schematic top view of the air heat exchanger 2 of the outdoor unit 100 of FIG. As shown in FIG. 2, the air heat exchanger 2 has a form called four-row air heat exchange, and is formed in a shape along the inner surface of the casing 8 of the outdoor unit 100. Specifically, it is composed of three rows of first heat exchangers 20 adjacent to each other and a second heat exchanger 25 adjacent to the first heat exchanger 20, and is bent in the direction of the second heat exchanger 25. The straight portion 2 a along the inner surface of the housing 8 and the bent portion 2 b along the corner of the housing 8 are provided. Note that the number of the bent portions 2 b of the air heat exchanger 2 may be appropriately selected according to the shape of the air heat exchanger 2. For example, when the air heat exchanger 2 has a shape along two side surfaces of the housing 8, it is only necessary to form one bent portion 2 b, and the air heat exchanger 2 has a shape along three side surfaces of the housing 8. In some cases, two bent portions 2b may be formed. In FIG. 2, the angle of the bent portion 2 b is shown as a right angle, but the angle of the bent portion 2 b is not limited and may be appropriately selected according to the shape of the housing 8.

  The heat transfer tube is formed in a plurality of steps in a side view by bending a plurality of tubes, and the shape of the heat transfer tube is such that air flowing in from the side surface of the housing 8 is easy to contact. In FIG. 2, as the first heat exchanger 20, a heat transfer tube and a rough fin are integrally illustrated, and as the second heat exchanger 25, a heat transfer tube and a smooth fin are integrally illustrated. The illustration is omitted.

  3A is a schematic view of the air heat exchanger 2 of FIG. 2, and FIG. 3B is an enlarged side view of the air heat exchanger 2 of FIG. 2 as viewed from the direction indicated by the arrow. In FIG. 3A, for convenience, the air heat exchanger 2 of FIG. As shown in FIG.3 (b), the 1st heat exchanger 20 is arrange | positioned on the outer side of the bending part 2b of the air heat exchanger 2, for example in layers, such as 3 rows. The first heat exchanger 20 includes a heat transfer tube 21 and a plurality of rough surface fins 22 through which the heat transfer tube 21 passes. The rough surface fins 22 are fins on which irregularities are formed. The air flowing between the rough fins 22 is turbulent by the cut and raised portions 22a of the rough fins 22 to promote heat exchange. The rough surface fin 22 is, for example, a cross fin in which a plurality of cut and raised portions 22a are formed.

  4A is a schematic diagram of the air heat exchanger 2 in FIG. 2, and FIG. 4B is a second heat exchanger 25 when the air heat exchanger 2 in FIG. 2 is viewed from the direction indicated by the arrow. FIG. As shown in FIG. 4, a second heat exchanger 25 adjacent to the plurality of first heat exchangers 20 is disposed inside the bent portion 2 b of the air heat exchanger 2. The second heat exchanger 25 includes a heat transfer tube 21 and a plurality of smooth fins 27 through which the heat transfer tube 21 is inserted. The smooth fins 27 are flat fins, and the resistance of air flowing between them is smaller than when flowing between the rough fins 22. The smooth fins 27 are, for example, ring fins having no irregularities such as cut and raised on the surface.

  When only the first heat exchanger 20 in which the rough surface fins 22 are arranged is arranged in the air heat exchanger 2 as in the conventional case, the first rough surface fins 22 are also provided inside the bent portion 2b. Since the heat exchanger 20 is arranged, the rough surface fins 22 come close to each other. This hinders the air flow, reduces the air blowing efficiency by the cut and raise 22a, and consequently causes the heat exchange efficiency to decrease. If the bent portion 2b is loosened so as to maintain the shape of the rough fins 22, the entire outdoor unit becomes large, and the occupied area increases, which is not preferable.

  In contrast, in the configuration of the present embodiment, the second heat exchanger 25 provided with the smooth fins 27 is disposed inside the bent portion 2b. Since the smooth fin 27 is not formed with notches or irregularities, even if the smooth fin 27 comes close to the bent portion 2b, the air flow is not hindered excessively. Further, even if the angle of the bent portion 2b is steep, the smooth fins 27 are not easily in contact with each other, and the local stress concentration of the smooth fins 27 is suppressed, so that the strength of the smooth fins 27 is kept high. Therefore, even when the air heat exchanger 2 is bent and accommodated in the housing 8, good blowing efficiency can be obtained while maintaining the heat exchange performance. And the outdoor unit 100 in which such an air heat exchanger 2 was accommodated can suppress the occupation area of the outdoor unit 100 small.

[Modification]
Fig.5 (a) is the schematic of the air heat exchanger 30 which concerns on a modification, FIG.5 (b) is from the direction which shows the linear part 30a of the air heat exchanger 30 of Fig.5 (a) by the arrow. FIG. Moreover, Fig.6 (a) is the schematic of the air heat exchanger 30 which concerns on a modification, FIG.6 (b) shows the bending part 30b of the air heat exchanger 30 of Fig.6 (a) with the arrow. It is the enlarged side view seen from the direction. As shown in FIG.5 and FIG.6, in this modification, the air heat exchanger 30 includes a first heat exchanger 31 arranged in three rows, and a second heat exchanger 35 arranged inside thereof. It is comprised by. Among these, rough surface fins 22 are provided on the straight portion 30 a of the first heat exchanger 31. Moreover, in the 2nd heat exchanger 35, the smooth fin 27 is provided in the bending part 30b, and the rough surface fin 22 is provided in the linear part 30a.

  The second heat exchanger 35 is provided with the smooth fins 27 at the bent portions 30b, and an increase in blowing resistance due to the adjacent smooth fins 27 is suppressed. Moreover, the rough surface fin 22 is provided in the linear part 30a among the 2nd heat exchangers 35, a turbulent flow is caused in air, and heat exchange is promoted. In this way, by using the smooth fins 27 only in regions where the increase in blowing resistance is a concern and using the rough fins 22 in other regions, the smooth fins 27 reduce the blowing resistance, while the rough fins 22 reduce the blowing resistance. It becomes possible to maintain high heat exchange efficiency.

  In addition to the above configuration, for example, different types of fins may be arranged in the step direction of the second heat exchanger 25. The unevenness formed on the rough fin 22 is not limited to the cut and raised 22a, and may be, for example, a form in which a small protrusion is attached.

[Performance evaluation]
In the performance evaluation, evaluation was performed based on an index defined in the Integrated Part Load Value abbreviated as IPLV. IPLV defines the coefficient of performance of the refrigerator at four different loads as an index, and evaluates the energy efficiency of the equipment based on the operating ratio at each load. As an evaluation object, the air heat exchanger of the conventional example employs the first heat exchanger 20 arranged in four rows and bent. Further, in the air heat exchanger 2 according to the present embodiment, three rows of the first heat exchanger 20 and one row of the second heat exchanger 25 are arranged and bent toward the second heat exchanger 25 side. Adopted.

  FIG. 7 is a scatter diagram showing the results of performance evaluation of the air heat exchanger 2 according to the present embodiment. The horizontal axis indicates the compressor capacity, and the vertical axis indicates the unit efficiency. Here, the unit efficiency indicates the energy efficiency of the air heat exchanger. Moreover, in FIG. 7, the rhombus shows the result obtained by the conventional air heat exchanger, and the square shows the result obtained by the air heat exchanger 2 according to the present embodiment.

  As shown in FIG. 7, when the partial load factor is reduced in both the present embodiment and the conventional example, the unit efficiency is increased. This means that the higher the rate of operation at a low partial load factor, the higher the energy efficiency, and the higher the rate of operation at a high partial load rate, the lower the energy efficiency. And in 50% and 25% with a low partial load factor, the unit efficiency of the air heat exchanger 2 which concerns on this Embodiment showed the value higher than the air heat exchanger of a prior art example. This is thought to be due to the fact that the use of smooth fins in the second heat exchanger reduced the blowing resistance, so that the power consumption of the fan decreased and the energy efficiency increased. As mentioned above, it was shown that the air heat exchanger 2 which concerns on this Embodiment can acquire favorable energy efficiency by providing a smooth fin in the 2nd heat exchanger inside a bending | flexion. In particular, the structure of the present embodiment is useful when operation with a low load is expected.

  According to the air heat exchanger 2 of the present invention described above, the second heat exchanger 25 including the flat smooth fins 27 is disposed inside the bent portion 2b. Thereby, in the bending part 2b, local stress concentration does not arise in the smooth fin 27, and even if the smooth fin 27 adjoins, it does not contact. For this reason, it is possible to prevent a decrease in strength due to local stress concentration and reduce the power consumption of the fan 3 and improve the heat exchange efficiency while reducing the occupied area.

  Further, by providing the rough surface fins 22 in the region other than the bent portion 2b of the second heat exchanger 25, turbulent flow occurs in the air flow, and heat exchange efficiency can be improved.

  In particular, even when a rough surface fin 22 with a cut and raised portion 22a is used, good heat exchange efficiency and air blowing efficiency are maintained.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2, 30 Air heat exchanger, 2a, 30a Straight part, 2b, 30b Bending part, 3 Fan, 4 Expansion valve, 5 Evaporator, 6a Inlet water piping, 6b Outlet water piping, 7 Refrigerant piping, 8 Case, 20, 31 1st heat exchanger, 21 Heat transfer tube, 22 Rough surface fin, 22a Cut and raise, 25, 35 2nd heat exchanger, 27 Smooth fin, 100 Outdoor unit.

Claims (3)

A plurality of first heat exchangers composed of a plurality of rough surface fins and heat transfer tubes that are inserted through the plurality of rough surface fins and through which the refrigerant flows;
A plurality of smooth fins , a plurality of rough surface fins , and a plurality of the smooth fins and the plurality of rough surface fins are inserted into the heat transfer tubes through which the refrigerant flows, and the plurality of first heat exchangers An adjacent second heat exchanger;
With
The first heat exchanger is bent toward the second heat exchanger;
The second heat exchanger is bent on the same side as the first heat exchanger,
Wherein the first heat exchanger, only the rough surface fins are provided,
In the bent region of the second heat exchanger, the smooth fin is provided,
The rough surface fin is provided in an unbent region of the second heat exchanger.
Air heat exchanger. The rough fin is
Cut or raised, or irregularities were formed,
The air heat exchanger according to claim 1 . Air heat exchanger according to claim 1 or 2, a compressor for compressing a refrigerant gas, a fan blows air to the air heat exchanger, an expansion valve for controlling the refrigerant amount, and the heat exchange between the water and the refrigerant A water heat exchanger, which has a housing for housing,
The air heat exchanger is provided along two adjacent surfaces of the inner surface of the housing.
Outdoor unit.

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