JPH11201679A - Heat exchanger with fin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deterioration of capacity at the time of heating operation due to the condensation of moisture or the formation of frost in winter, and to extend the time of heating operation, concerning a heat exchanger with a fin, which is used for air conditioners and refrigerating machines, and which receives and transmits heat between refrigerant and fluid such as air. SOLUTION: A slit-shaped perpendicularly louvered part 7, which has a section 7' that is formed to be perpendicular to the draft direction, is provided only at the draft downstream side row of a fin 5 surface, and heat insulating cuts 8 are provided on the fin 5 surface near a heat transfer tube 2 that is located at the upstream side from the center line connecting the heat transfer tubes 2 at the draft upstream side, in such a manner that they become parallel to the draft direction. Thereby, frosting to the draft upstream side leading edge part of the fin 5 that is located between the heat insulating cuts 8 between each of the heat transfer tubes 2 is suppressed, and the time of heating operation can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finned heat exchanger used in an air conditioner or a refrigeration system for transferring heat between a refrigerant and a fluid such as air.

[0002]

2. Description of the Related Art In a heating operation of a heat pump type air conditioner using air as a heat source, an outdoor heat exchanger functions as an evaporator. Condense. Furthermore, when the refrigerant evaporation temperature becomes 0 ° C. or lower, condensed water solidifies and frost is formed. Since the ventilation resistance of the heat exchanger increases due to the condensed water or frost and the heating capacity decreases, the defrosting operation is performed periodically.

A conventional finned heat exchanger is disclosed in Japanese Patent Application Laid-Open No. 62-69096.

Hereinafter, an example of the conventional finned heat exchanger will be invented with reference to the drawings.

FIG. 4 is a perspective view showing a conventional finned heat exchanger. In FIG. 4, reference numeral 1 denotes fins made of aluminum or the like, which are arranged in parallel at regular intervals, and 2 is a plurality of fins made of copper or the like which are inserted at right angles to the fins 1 and arranged in the airflow direction. Heat tube. The heat transfer tubes 2 are connected to each other at both ends of the heat exchanger to form a refrigerant circuit.

FIG. 5 is a sectional view of a conventional finned heat exchanger, and FIG. 6 is a sectional view taken along line AA in FIG. In the figure, reference numeral 3 denotes a fin collar which joins the fin 1 and the heat transfer tube 2, and 4 denotes a slit-like cut-and-raised portion provided so that the cut surface 4 'is perpendicular to the air flow direction. It is provided so as to protrude alternately on the surface.

The operation of the finned heat exchanger configured as described above will be described below.

In FIG. 1, a refrigerant such as chlorofluorocarbon circulates inside the heat transfer tube 2, and the heat of the refrigerant is transmitted from the heat transfer tube 2 to the fin collar 3, cut and raised through the fins 1 and transmitted to the fins 4. The cut-and-raised portion 4 renews the boundary layer of the air flowing between the fins 1 to promote the heat exchange between the air and the fins, and as a result, promotes the heat exchange between the air and the refrigerant flowing inside the heat transfer tube 2. Was.

[0009]

However, in the conventional finned heat exchanger, when the ambient air temperature decreases during the heating operation, the evaporation temperature of the refrigerant decreases and the temperature of the refrigerant decreases to 0 ° C. or less. There is a problem that frost grows in the vicinity of the fin leading edge on the upstream side of the airflow and the heating capacity is reduced, so that the heating operation must be stopped and the defrosting operation must be performed periodically.

The present invention solves the conventional problem.
An object of the present invention is to make it possible to extend a heating operation time by improving a fin shape.

In the conventional finned heat exchanger, when the ambient air temperature decreases during the heating operation, the evaporation temperature of the refrigerant decreases, so that moisture condenses near the fin leading edge on the upstream side of the airflow, and the heat exchanger However, there is a problem that the heating capacity is reduced due to an increase in ventilation resistance. Further, when the evaporation temperature of the refrigerant becomes 0 ° C. or lower, the condensed water solidifies and becomes frost, and the heating capacity is further reduced. Thus, the heating operation is stopped although heat exchange can be performed on the downstream side of the airflow. However, there is a problem that the defrosting operation has to be performed periodically.

The present invention solves the conventional problem.
An object of the present invention is to improve the capacity during the heating operation and extend the heating operation time by improving the fin shape.

[0013]

In order to solve this problem, the present invention provides a slit-shaped vertical cut-out in which the cut surface is perpendicular to the air flow direction only in the air flow downstream row of the fin surface. In addition, a heat insulating cut is provided on the fin surface near the heat transfer tube located upstream of the center line connecting the heat flow tubes on the upstream side of the air flow so as to be parallel to the air flow direction. Thereby, frost formation near the fin leading edge during the heating operation can be suppressed, and the heating operation time can be extended.

A slit-shaped vertical cut-and-raised surface whose cut surface is perpendicular to the air flow direction is provided only in the air flow downstream row on the surface of the fins, and is provided upstream of the center line connecting the heat transfer tubes on the air flow upstream side. On the fin surface near the heat transfer tube located on the side, the cut surface is parallel to the airflow direction, the height of the cut and raised is raised and raised from both ends to the center, and a slit-shaped parallel cut and raised Is provided, it is possible to improve the capacity during the heating operation and extend the heating operation time.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plurality of fins arranged in parallel in a gas flow direction, wherein fins are arranged in parallel at regular intervals and gas flows between the fins, and fluid flows through the fins. And a slit-shaped vertical cut-out where the cut surface is perpendicular to the airflow direction is provided only in the airflow downstream row on the surface of the fins, and upstream from the center line connecting the heat transfer tubes on the airflow upstream side A heat exchanger with fins provided with heat insulating cuts so as to be parallel to the air flow direction on the fin surface near the heat transfer tube located on the side, and slit-shaped cut-and-raised portions are provided only in the downstream row of the air flow By providing a notch for heat insulation on the fin surface near the heat transfer tube located on the upstream side of the center line connecting the heat transfer tubes on the upstream side of the air flow so as to be parallel to the air flow direction, the heat transfer tube Between the thermal cuts On the fin leading edge, suppressing heat conduction from the heat transfer tube, suppressing the frost amount at the time of heating operation to this part, an effect that can be extended heating operation time.

The fins are arranged in parallel at regular intervals, and have fins through which gas flows, and heat transfer tubes arranged in a plurality of rows in the gas flow direction, through which the fluid flows through the fins. Only in the airflow downstream row of the surface of the surface, provided a slit-shaped vertical cut and raised that the cut surface is perpendicular to the airflow direction, the heat transfer tube located upstream from the center line connecting the heat transfer tubes on the upstream side of the airflow On the nearby fin surface, the cut surface is parallel to the air flow direction, and the height of the cut and raised is provided with a slit-shaped parallel cut and raised that is high from both ends to the center toward the center. Is an exchanger,
The cut surface is parallel to the airflow direction, and the height of the cut-and-raised portion is raised from both ends to the center. At the same time as improving the capacity during operation, the heat transfer from the heat transfer tubes to the fin front edge located between the parallel cut-and-raised heat transfer tubes can be suppressed, and the heating operation time can be extended. Having.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In addition, about the same structure as a conventional one, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

Embodiment 1 FIG. 1 is a sectional view of a finned heat exchanger according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 2 denotes a heat transfer tube which is the same as the conventional structure. Numerals 5 are fins arranged in parallel at regular intervals. The fins 5 have a configuration in which gas flows between the fins 5 and heat exchange between the refrigerant flowing in the heat transfer tube 2 and the airflow flowing between the fins 5. A fin collar 6 joins the fin 5 and the heat transfer tube 2.

7 protrudes alternately from the front and back from the fin 5 surface,
In addition, it is a vertical cut-and-raised portion in which the cut surface 7 'is perpendicular to the airflow direction.

Reference numeral 8 denotes a heat insulating notch provided on the fin 5 near the heat transfer tube 2 located upstream of the center line connecting the heat flow tubes 2 on the upstream side of the air flow so as to be parallel to the air flow direction. It is.

The operation of the finned heat exchanger configured as described above will be described below.

In the figure, the heat from the refrigerant circulating inside the heat transfer tube 2 is divided into heat transfer tubes 2, fin collars 6, fins 5.
Through the vertical cut-and-raise 7. At this time, heat exchange is performed with the airflow flowing between the fins 5, and water droplets are condensed on the front edge of the fin 5 on the upstream side of the airflow and vertically cut and raised.

However, the fins 5 in the vicinity of the heat transfer tubes 2 located on the upstream side of the center line connecting the heat transfer tubes 2 on the upstream side of the airflow.
The heat-insulating cuts 8 provided on the surface so as to be parallel to the airflow direction allow the heat-transfer tubes 2 to move to the front edge of the fin 5 located between the heat-insulating cuts 8 between the heat transfer tubes 2. Heat conduction is suppressed, and the amount of condensed water droplets on this portion is reduced.

When the ambient air temperature is low, the evaporation temperature of the refrigerant drops, and the condensed water droplets freeze and become frost, which grows unevenly at the leading edge on the upstream side of the airflow. Since the amount of condensed water droplets is small at the upstream edge of the airflow upstream of the fin 5 located therebetween, the amount of frost is small, and as a result, a flow path of the airflow is secured and the heating operation time can be extended.

(Embodiment 2) FIG. 2 is a sectional view of a finned heat exchanger according to Embodiment 2 of the present invention, and FIG. 3 is a sectional view taken along line BB of FIG.

In FIG. 1, reference numeral 2 denotes a heat transfer tube which is the same as the conventional structure. Numerals 9 are fins arranged in parallel at regular intervals. The fins 9 are configured such that a gas flows between the fins 9 and a refrigerant flowing in the heat transfer tube 2 and an airflow flowing between the fins 9 exchange heat. A fin collar 10 joins the fin 9 and the heat transfer tube 2.

Numeral 11 denotes a vertical cut-and-raised portion which protrudes alternately from the front and back from the surface of the fin 9 and is cut and raised so that the cut surface 11 'is perpendicular to the air flow direction.

Reference numeral 12 denotes a cut surface 12 'parallel to the direction of the air flow on the fin 5 near the heat transfer tube 2 located on the upstream side of the center line connecting the heat transfer tubes 2 on the upstream side of the air flow. It is a slit-shaped parallel cut-and-raised shape whose height is higher from both ends toward the center and has a mountain shape.

The operation of the finned heat exchanger configured as described above will be described below.

In the figure, heat from the refrigerant circulating in the heat transfer tube 2 passes through the heat transfer tube 2, the fin collar 10, and the fin 9, and is vertically cut and raised 11 and parallel cut and raised 12.
Transmitted to At this time, heat exchange is performed with the airflow flowing between the fins 9, and water droplets are condensed on the front edge of the fin 9 on the upstream side of the airflow and vertically cut and raised 11 and parallel cut and raised 12.
Further, when the ambient air temperature is low, the evaporation temperature of the refrigerant decreases, and the condensed water droplets freeze and become frost, which grows unevenly toward the upstream edge of the airflow upstream side. These condensed water droplets and frost increase the ventilation resistance of the heat exchanger with fins and decrease the heating capacity.

However, the cut surface 1 of the parallel cut and raised 12
Since the airflow 2 ′ is generated in parallel to the airflow direction, the airflow collides with the end face 12 ″ of the parallel cutout 12 to promote the turbulence effect of the air and improve the capacity during the heating operation. Can be done.

Further, the parallel cut-and-raised portion 12 has a cut surface parallel to the air flow direction on the fin 9 near the heat transfer tube 2 located on the upstream side of the center line connecting the heat transfer tubes 2 on the upstream side of the air flow. Therefore, heat conduction from the heat transfer tube 2 to the front edge of the fin 9 located between the parallel cut-and-raised portions 12 between the heat transfer tubes 2 is suppressed, and the amount of condensed water droplets on this portion is reduced. Alternatively, since the amount of frost decreases, a flow path of the airflow is secured, and the heating operation time can be extended.

[0034]

As described above, according to the present invention, a vertical cut-and-raised portion whose cut surface is perpendicular to the airflow direction is provided only in the airflow downstream row on the surface of the fin, and the heat transfer tubes on the upstream side of the airflow are provided. On the fin surface near the heat transfer tube located on the upstream side from the center line connecting the heat transfer tubes, heat insulation cuts are provided so as to be parallel to the airflow direction. The advantageous effect that the amount of frost on the located fin front edge portion can be suppressed and the heating operation time can be extended can be obtained.

Further, a vertical cut-and-raised portion whose cut surface is perpendicular to the airflow direction is provided only in the row of the fins on the downstream side of the airflow, and is located upstream of the center line connecting the heat transfer tubes on the upstream side of the airflow. On the fin surface near the heat transfer tube, the cut surface is parallel to the air flow direction, and the height is increased from both ends toward the center, and a mountain-shaped parallel cut and raised is provided.
The turbulence effect of the air is promoted, and the capacity during the heating operation can be improved.At the same time, the amount of frost on the front edge of the fin located between the parallel cutting and raising between the heat transfer tubes is suppressed, and the heating is performed. The advantageous effect that the operation time can be extended can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a finned heat exchanger according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view of a finned heat exchanger according to Embodiment 2 of the present invention.

FIG. 3 is a sectional view taken along line BB in FIG. 2;

FIG. 4 is a perspective view of a conventional finned heat exchanger.

FIG. 5 is a cross-sectional view of a conventional finned heat exchanger.

6 is a sectional view taken along line AA in FIG.

[Explanation of symbols]

 2 Heat transfer tube 5, 9 Fin 7, 11 Vertical cut and raised 7 ', 11', 12 "Cut plane 8 Cut for heat insulation 12 Parallel cut and raised

Claims (2)

[Claims] 1. A fin comprising a plurality of fins which are arranged in parallel at regular intervals and through which a gas flows, and a plurality of heat transfer tubes which pass through the fins and through which a fluid flows, and which are arranged in a plurality of rows in a gas flow direction, Only in the air flow downstream row of the surface of the fins, a cut surface is provided with a slit-shaped vertical cut and raised perpendicular to the air flow direction, and the cut surface is located on the upstream side of the center line connecting the heat transfer tubes on the air flow upstream side. A heat exchanger with fins, wherein a heat insulating cut is provided on the fin surface in the vicinity of the heat transfer tube so as to be parallel to the airflow direction. 2. The fins are arranged in parallel at regular intervals, and have fins through which gas flows, and heat transfer tubes arranged in a plurality of rows in the gas flow direction, through which the fluid flows, and Only in the air flow downstream row of the surface of the fins, a cut surface is provided with a slit-shaped vertical cut and raised perpendicular to the air flow direction, and the cut surface is located on the upstream side of the center line connecting the heat transfer tubes on the air flow upstream side. On the fin surface in the vicinity of the heat transfer tube, the cut surface is parallel to the airflow direction, the height of the cut and raised is raised and raised from both ends toward the center, and a slit-shaped parallel cut and raised is formed. Heat exchanger with fins provided.