US20070151713A1

US20070151713A1 - Heat exchanger

Info

Publication number: US20070151713A1
Application number: US11/646,334
Authority: US
Inventors: Han Lee; Dong Jang; Sang Lee; Ju Kim; Yong Sa
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2005-12-31
Filing date: 2006-12-28
Publication date: 2007-07-05
Also published as: CN1991290A; CN1991290B

Abstract

A heat exchanger is provided. The heat exchanger includes a tube through which a refrigerant flows, a fin disposed on an outer periphery of the tube, and an agitating member inserted into the tube, and agitating the refrigerant.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a heat exchanger, and more particularly, to a refrigerant tube structure of a heat exchanger that improves heat exchange efficiency by increasing a contact area between a liquid refrigerant flowing through a refrigerant tube and an inner periphery of the refrigerant tube.
2. Description of the Related Art
In general, a fin-tube type heat exchanger used in an air conditioner or the like includes a refrigerant tube having the shape of a meander line which is curved a plurality of times, and a plurality of heat exchange fins inserted into the refrigerant tube in a direction that the heat exchange fins are intersected with the refrigerant tube.
The related art fin-tube type heat exchanger acts as an evaporator or a condenser in such a way that a refrigerant exchanges heat with external air while the refrigerant flowing through the refrigerant tube. Specifically, a heat exchange area between the refrigerant and the external air is increased by means of the heat exchange fins which are inserted into the refrigerant tube and arranged close to each other. Thus, a heat exchange is effectively performed.
In addition, grooves are formed on an inner periphery of the refrigerant tube of the fin-tube type heat exchanger for improving heat exchange efficiency. Here, the grooves are spirally formed such that they are connected in a longitudinal direction of the refrigerant tube.
In virtue of the grooves, when the heat exchanger is used as an evaporator, the contact area between the liquid refrigerant and the refrigerant tube is increased, and thus the heat exchange efficiency is improved. Besides, when the heat exchanger is used as a condenser, the contact area between the vapor refrigerant and the refrigerant tube is increased so that the heat exchanger having the grooves is advantageous in improving the heat exchange efficiency.
Meanwhile, when the heat exchanger having the related art refrigerant tube is used as the evaporator, the liquid refrigerant flows at an outlet portion of the refrigerant tube. When the heat exchanger is used as the condenser, the liquid refrigerant flows at an inlet portion of the refrigerant tube. Such a refrigerant flows along a bottom surface of the refrigerant tube due to gravity.
Specifically, when the related art heat exchanger having the above-described refrigerant tube is used as an evaporator, the liquid refrigerant flows into the inlet of the evaporator. Therefore, the contact area between the refrigerant and the inner periphery of refrigerant tube is decreased at the inlet of the evaporator, and thus the heat exchange efficiency of the heat exchanger is degraded. That is, there is a drawback that the refrigerant is not completely vaporized because the degree of superheat of the evaporator is lowered.
Moreover, when the heat exchanger is used as a condenser, the liquid flows through the outlet of the condenser. Accordingly, the contact area between the liquid refrigerant and the inner periphery of the refrigerant tube is decreased at the outlet of the condenser, and thus the heat exchange efficiency of the heat exchanger is degraded. That is, there is a drawback that the refrigerant is not completely liquidized because the degree of supercooling of the condenser is lowered.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a heat exchanger that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a heat exchanger that improves heat exchange efficiency by increasing a contact area between a refrigerant and an inner periphery of a refrigerant tube at an inlet of the refrigerant when the heat exchanger is used as an evaporator.
Another object of the present invention is to provide a heat exchanger that improves heat exchange efficiency by increasing a contact area between a refrigerant and an inner periphery of a refrigerant tube at an outlet of the refrigerant when the heat exchanger is used as a condenser.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a heat exchanger, including: a tube through which a refrigerant flows; a fin disposed on an outer periphery of the tube; and an agitating member inserted into the tube, and agitating the refrigerant.
In another aspect of the present invention, there is provided a heat exchanger, including: a tube; a fin contacting the tube to be thermally in contact with an external air; and an agitating member spiraled a plurality of times for increasing a contact area between a liquid refrigerant and an inner periphery of the tube, the agitating member being provided inside the tube.
When the heat exchanger according to the present invention is used as an evaporator, a contact area between a liquid refrigerant and an inner periphery of the refrigerant tube at an inlet of the evaporator is increased. Thus, it is possible to increase heat exchange efficiency.
In addition, when the heat exchanger according to the present invention is used as condenser, a contact area between a liquid refrigerant and an inner periphery of the refrigerant tube at an outlet of the condenser is increased. Thus, it is possible to increase heat exchange efficiency.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
FIG. 1 is a perspective view of a heat exchanger according to the preset invention;
FIG. 2 is a sectional view of a refrigerant tube according to a refrigerant tube;
FIG. 3 is an exploded perspective view illustrating a connection of the refrigerant tube according to the present invention;
FIG. 4 is a partially sectional perspective view taken along line I-I of FIG. 3; and
FIG. 5 is a graph of experimental data illustrating a performance comparison result of a related art heat exchanger and the heat exchanger according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
FIG. 1 is a perspective view of a heat exchanger 1 according to the present invention.
Referring to FIG. 1, the heat exchanger 1 according to the present invention includes a refrigerant tube 10 through which a refrigerant flows, heat exchange fins 20 penetrated by the refrigerant tube 10 and arranged at regular distances, and an agitating member 30 inserted into the refrigerant tube 10.
Specifically, the heat exchange fin 20 is formed from a thin plate with high thermal conductivity and is attached on an outer periphery of the tube 10, thereby increasing a heat exchange area between the refrigerant and an air current S and thermal conductivity.
FIG. 2 is a sectional view of the refrigerant tube 10 according to a refrigerant tube.
Referring to FIG. 2, a plurality of protrusions 13 are formed on an inner periphery of the refrigerant tube 10 in spiral shape.
In detail, the protrusions 13 are formed such that they scrape along the inner periphery of the refrigerant tube 10 in a spiral direction. These protrusions 13 play a role in improving heat transfer capability by increasing a contact area with the refrigerant tube 10 when the refrigerant flows through the refrigerant tube 10.
The agitating member 30 having a helical shape is inserted into the refrigerant tube 10. Specifically, the agitating member 30 changes the flow of the refrigerant flowing through the refrigerant tube 10 so that the contact area between the refrigerant and the inner periphery of the refrigerant tube 10 is increased.
That is, the flow of the refrigerant flowing through the refrigerant tube 10 is changed into turbulent flow from laminar flow, which increases the contact area between the refrigerant and the refrigerant tube 10.
FIG. 3 is an exploded perspective view illustrating a connection of the refrigerant tube 10 according to the present invention, and FIG. 4 is a partially sectional perspective view taken along line I-I of FIG. 3.
Referring to FIG. 3, the refrigerant tubes 10 of the heat exchanger 1 according to the present invention is prepared such that a plurality of U-shaped pipes are mutually connected to each other by a return band 11. The agitating member 30 is inserted into an end of the refrigerant tube 10.
Here, the agitating member has a length extending from one end of the refrigerant tube 10 to the other end from which a curvature starts. Therefore, turbulence phenomenon does not occur due to the flow of the refrigerant in a state that the agitating member 30 is inserted into the refrigerant tube 10.
Referring to FIG. 4, the agitating member 30 according to the present invention is shaped such that a rim-shaped member with a predetermined width and thickness T is spirally wound.
In detail, the spirally shaped agitating member 30 is formed in the shape of a spring having a predetermined inner diameter D1 and a predetermined outer diameter D2.
In more detail, it is preferable that the inner diameter D1 of the agitating member 30 be 25-40% of an inner diameter D3 of the refrigerant tube 10 in consideration of flow resistance of the refrigerant and the contact area between the liquid refrigerant and the inner periphery of the refrigerant tube 10.
In other words, when the diameter D1 of the agitating member 30 is less than 25% of the inner diameter D3 of the refrigerant tube 10, the contact area between the liquid refrigerant and the refrigerant tube 10 is increased and a flow resistance of the refrigerant is increased as well. Therefore, the heat exchange capability of the heat exchanger 1 is degraded.
On the contrary, when the inner diameter D1 of the agitating member 30 is greater than 40% of the inner diameter D3 of the refrigerant tube 10, the flow resistance of the refrigerant is decreased and the contact area between the liquid refrigerant and the refrigerant tube 10 is also decreased, which causes the heat exchange capability of the heat exchanger 1 to be degraded.
In addition, in consideration of a contact area between the protrusions 13 formed in the refrigerant tube 10 and the flow resistance of the refrigerant, it is preferable that the outer diameter D2 of the agitating member 30 be 95% or less of the inner diameter D3 of the refrigerant tube 10.
That is, when a diameter D2 of the agitating member 30 is greater than 95% of the diameter D3 of the refrigerant tube 10, the contact area between the refrigerant and the protrusion 13 is increased but the flow resistance of the refrigerant is also increased, whereby the heat exchange capability of the thermal exchanger 1 is degraded.
In addition, to reduce the flow resistance of the refrigerant, it is preferable that a distance P between pitches of the agitating member 30 be greater than the inner diameter D3 of the refrigerant tube 10 at least.
Preferably, the agitating member 30 having the above shape is inserted into an inside portion of the refrigerant tube 30 through which the liquid refrigerant flows.
In other words, a vapor refrigerant can contact the inner periphery of the refrigerant tube 10 with ease but the liquid refrigerant is generally in contact with a bottom portion of the refrigerant tube 10 due to its own viscosity and gravity. Thus, it is preferable that the liquid refrigerant flowing through the refrigerant tube 10 contacts the inner periphery of the refrigerant tube 10 to increase a heat exchange area.
Specifically, when the heat exchanger 1 is used as an evaporator, a binary phase refrigerant that has undergone an expansion procedure flows into an inlet of the evaporator. Since the amount of liquid refrigerant is more than the amount of vapor refrigerant at the inlet of the evaporator, it is preferable that the agitating member 30 be provided to the inlet of the evaporator.
Contrariwise, when the heat exchanger 1 is used as a condenser, a vapor refrigerant with high pressure and temperature that has passed through a compressor flows into an inlet of the condenser, and a liquid refrigerant with high temperature flows into an outlet of the condenser through condensation procedure. Accordingly, it is preferable that the agitating member 30 be provided to the outlet of the condenser.
Thereinafter, the performance of the heat exchanger 1 having the above-mentioned structure will be described with reference to a graph showing experimental data.
FIG. 5 is a graph of experimental data illustrating a performance comparison result of a related art heat exchanger and the heat exchanger according to the present invention.
Referring to FIG. 5, when the heat exchanger 1 is used as an evaporator, a low temperature liquid refrigerant flows into the inlet of the evaporator, and is heat-exchanged with an external air while it flowing through the refrigerant tube 10 so that the low temperature liquid refrigerant is changed into a low temperature vapor refrigerant. In detail, the liquid refrigerant flowing through the refrigerant tube 10 absorbs the heat of the air current S transferred through the fin 20. Therefore, the low temperature liquid refrigerant is changed into the vapor refrigerant and the vapor refrigerant then flows out through the outlet of the evaporator. The heat of the air current S is transferred to the refrigerant, and thus the air becomes cool.
Meanwhile, it was confirmed that the heat of evaporation of the evaporator employing the inventive refrigerant tube 10 having the agitating member 30 is increased to 101.7% assuming that the heat of evaporation of the related art heat exchanger be 100%. That is, when the heat exchanger 1 having the refrigerant tube structure according to the present invention is used as the evaporator, it was understood from FIG. 5 that the heat exchanger absorbs more heat, i.e., about 1.7%, from the air current S in comparison with the related art evaporator, and thus its heat exchanging capability is improved.
In addition, when the heat exchanger 1 is used as a condenser, a high temperature vapor refrigerant flows into an inlet of a condenser, and is changed into a high temperature liquid refrigerant while it flowing through the refrigerant tube 10. That is, after the heat of the vapor refrigerant is released into the air current S through the fins 20 so that the vapor refrigerant is changed into the liquid refrigerant, the liquid refrigerant flows out through the outlet of the condenser.
Furthermore, it was confirmed from FIG. 5 that the heat of condensation of the condenser employing the inventive refrigerant tube 10 is increased to 102.7% assuming that the heat of condensation of the related art heat exchanger be 100%. That is, when the heat exchanger having the refrigerant tube structure according to the present invention is used as the condenser, it was understood that the heat exchanger release more heat, i.e., about 2.7%, into the air current S in comparison with the related art evaporator, and thus its heat exchanging capability is improved.
As described above, according to the present invention, the amount of heat exchange of the refrigerant with the external air can be increased by inserting the agitating member 30 into the refrigerant tube 10, because the agitating member 30 increases the contact area with the inner periphery of the refrigerant tube by changing the flow of the refrigerant.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

1. A heat exchanger comprising:

a tube through which a refrigerant flows;

a fin disposed on an outer periphery of the tube; and

an agitating member inserted into the tube, and agitating the refrigerant.

2. The heat exchanger according to claim 1, wherein the agitating member has a helical shape.

3. The heat exchanger according to claim 1, wherein the agitating member is disposed in a section where a liquid refrigerant flows.

4. The heat exchanger according to claim 1, wherein a distance between pitches of the agitating member is greater than an inner diameter of the tube.

5. The heat exchanger according to claim 1, wherein a plurality of protrusions are formed on an inner periphery of the tube.

6. The heat exchanger according to claim 1, wherein the agitating member is provided in a linear section of the tube.

7. A heat exchanger comprising:

a tube;

a fin contacting the tube to be thermally in contact with an external air; and

an agitating member spiraled a plurality of times for increasing a contact area between a liquid refrigerant and an inner periphery of the tube, the agitating member being provided inside the tube.

8. The heat exchanger according to claim 7, wherein the agitating member is curved in a direction different from a flow direction of a refrigerant.

9. The heat exchanger according to claim 7, wherein an outer diameter of the agitating member is 95% or less of an inner diameter of the tube.

10. The heat exchanger according to claim 7, wherein an inner diameter of the agitating member is 25%˜40% of an inner diameter of the tube.

11. The heat exchanger according to claim 7, wherein the agitating member is provided to an outlet of the tube when a refrigerant passing through a compressor flows into the tube.

12. The heat exchanger according to claim 7, wherein the agitating member is provided to an inlet of the tube when the refrigerant undergoing an expansion procedure flows into the tube