US20080156469A1

US20080156469A1 - Ventilating apparatus, heat exchange apparatus, heat exchange element, and rib therefor

Info

Publication number: US20080156469A1
Application number: US11/853,132
Authority: US
Inventors: Woo Ram Lee; Sung Won Han; Han Lim Choi
Original assignee: Individual
Current assignee: LG Electronics Inc
Priority date: 2006-12-27
Filing date: 2007-09-11
Publication date: 2008-07-03
Also published as: CN101210790A; EP1939574A1; KR20080060933A

Abstract

A ventilating apparatus, a heat exchange apparatus, a heat exchange element, and a rib therefor are provided. The heat exchange element includes a plurality of heat exchange sheets which are multi-stacked, and a plurality of ribs arranged between the heat exchange sheets to form ducts with the heat exchange sheets. Each of the plurality of ribs includes an irregular structural surface including an uneven portion. The uneven portion may include a recess portion, a protrusion portion, or a combination of a recess portion and a protrusion portion, which generates a turbulent flow in a heat exchange gas flowing through the duct. Such heat exchange element having such a rib may minimize duct resistance by suppressing a laminar flow and growth of a boundary layer in airflow of outdoor and indoor air passing through a heat exchanger, and may further increase heat exchange efficiency because the heat exchange gas may be introduced/exhausted smoothly at a low flow velocity.

Description

This application claims priority to Korean Application No. 10-2006-0135574, filed in Korea on Dec. 27, 2006, which is hereby incorporated herein by reference in its entirety.

BACKGROUND

1. Field
A ventilating apparatus, a heat exchange apparatus, a heat exchange element, and a rib therefor are disclosed herein.
2. Background
Ventilating apparatus and heat exchange apparatus are known. However, they suffer from various disadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:

FIG. 1 is a perspective view of internal structure of a ventilating apparatus according to an embodiment;

FIG. 2 is a sectional view illustrating introduction/exhaust of outdoor air in the ventilating apparatus of FIG. 1;

FIG. 3 is a sectional view illustrating introduction/exhaust of indoor air in the ventilating apparatus of FIG. 1;

FIG. 4 is an exploded perspective view of heat exchange elements having ribs without irregular structural surfaces;

FIGS. 5 and 6 are sectional views of a velocity distribution of heat exchange gas in the heat exchange element of FIG. 4;

FIG. 7 is a sectional view of heat exchange elements having ribs with irregular structural surfaces according to an embodiment;

FIG. 8 is a sectional view of a rib with an irregular surface structure in the form of an uneven portion having irregular shapes and random arrangement of an uneven portion according to an embodiment; and

FIG. 9 is a perspective view of a heat exchange element having ribs with irregular structural surfaces according to an embodiment.

DETAILED DESCRIPTION

In general, a ventilating apparatus, which is an air conditioning apparatus used for ventilating an enclosed space, for example, a room, functions to heat exchange incoming outdoor air with outgoing indoor air before the outdoor air is introduced indoors. In other words, the ventilating apparatus is a kind of air conditioning apparatus that ventilates a room, such that an indoor temperature does not decrease or increase abruptly even though the outdoor air is introduced during ventilation.
A ventilating apparatus that performs both a heat-exchange function and a moisture-exchange function between incoming air and outgoing air is configured with a plurality of ducts that are arranged to cross one another or arranged in parallel. The outdoor air and the indoor air, which will be heat exchanged with each other, flow in different directions through each of adjacent ducts.
An important performance factor in a related art ventilating apparatus is to maintain the temperature and humidity of air at an inlet portion to be almost equal to the temperature and humidity of air at an outlet portion by heat exchanging and moisture exchanging the indoor air with the outdoor air. To accomplish this, components of the heat exchanger constituting each of the ducts must have maximum heat transfer efficiency and moisture permeability, and each of the ducts must be arranged small and compact as possible to contact air over the broadest surface area.
In addition to the above, it is necessary to minimize noise and power consumption in introducing fresh outdoor air and exhausting indoor air for ventilation. To minimize noise and power consumption, the conduit resistance of an internal heat exchange duct must be low. However, it is undesirable to reduce the size of a duct without limit and increase a length and density of a duct infinitely in order to realize the above conditions.
Therefore, to satisfy the incompatible conditions disclosed above at the same time, a variety of shapes and materials of ducts have been developed. One heat exchange duct includes heat exchange sheets and ribs that maintain the multi-stacked arrangement of the heat exchange sheets. Main heat exchange is performed through heat transfer and moisture permeation between the heat exchange sheets. The heat exchange sheet may be made of thin paper, and thus, the heat exchange sheet may sag if it absorbs moisture.
Further, the ribs may be attached to the heat exchange sheet in molten resin form and then cured to thereby constitute ducts with the heat exchange sheet. The ribs may be provided on both sides of the heat exchange sheet, and thus different gases (these gases may be outdoor air and indoor air typically, but there is no particular limitation) flow in such a way that they cross each other or flow in an opposite direction (for example, in parallel and opposite directions to each other). In such a case, there may occur a case where pressure or flow velocity is not uniform in each duct or even in the same duct depending on specific positions.
FIG. 1 is a perspective view of internal structure of a ventilating apparatus according to an embodiment FIG. 2 is a sectional view illustrating introduction/exhaust of outdoor air in the ventilating apparatus of FIG. 1. FIG. 3 is a sectional view illustrating introduction/exhaust of indoor air in the ventilating apparatus of FIG. 1. Referring to FIG. 1, the ventilating apparatus 10 may include a case 11 forming an external shape, a heat exchanger 20 received in the case 11, an intake fan 16, shown in FIG. 2, configured to introduce outdoor air, and an exhaust fan 17, as shown in FIG. 3 configured to introduce indoor air. The heat exchanger 20 may heat exchange incoming outdoor air and outgoing indoor air with each other.
More specifically, an intake air inlet 12 that introduces outdoor air and an exhaust air outlet 15 that exhausts indoor air to the outside may be provided at one side of the case 11. At the other side of the case 11, an intake air outlet 13 that discharges the introduced outdoor air to the indoor space, and an exhaust air inlet 14 that introduces the indoor air may be provided.
An intake passage may be provided between the intake air inlet 12 and the intake air outlet 13 in the form of a duct. The heat exchanger 20 may be positioned in a middle portion of the intake passage or duct. An exhaust passage may also provided between the exhaust air inlet 14 and the exhaust air outlet 15 in the form of a duct. Likewise, the heat exchanger 20 may be positioned in a middle portion of the exhaust passage or duct. The outdoor air introduced through the intake air inlet 12 and the indoor air introduced through the exhaust air inlet 14 may be heat exchanged with each other without being mixed, while passing through the heat exchanger 20.
As set for the above, FIG. 2 is a sectional view illustrating the introduction/exhaust of outdoor air in the ventilating apparatus of FIG. 1, while FIG. 3 is a sectional view illustrating the introduction/exhaust of indoor air in the ventilating apparatus of FIG. 1. Referring to FIG. 2, the intake fan 16 may be mounted inside the duct at a side of the intake air outlet 13 to introduce the outdoor air. The outdoor air may be introduced through the intake air inlet 12 by operation of the intake fan 16, and then may be heat exchanged with the indoor air while passing through the heat exchanger 20.
Referring to FIG. 3, the exhaust fan 17 may be mounted inside the duct at a side of the exhaust air outlet 15 to introduce the indoor air. The indoor air is introduced through the exhaust inlet 14 by the operation of the exhaust fan 17, and the indoor air is then heat exchanged with the outdoor air while passing through the heat exchanger 20.
The heat exchanger 20 may include a plurality of stacked heat exchange plates. The heat exchange plates may be configured such that guide ribs are disposed between heat exchange sheets. The combination structure of the heat exchange sheet and the guide rib may constitute a duct that guides the introduced indoor air or outdoor air. The duct through which the indoor air flows and the duct through which the outdoor air flows may be cross-arranged at left and right sides of the heat exchange sheet, respectively. Therefore, the outdoor air and the indoor air may be only heat exchanged with each other without being mixed, while they pass through the heat exchanger 20.
FIG. 4 is an exploded perspective view of a heat exchange element. Referring to FIG. 4, the heat exchange element may be in the shape of a hexagonal plane as a unit element. In more detail, an intake heat exchange element 21 and an exhaust heat exchange element 22, which both may have hexagonal shapes, may be alternately stacked. The intake passage and the exhaust passage are provided between the intake heat exchange element 21 and the exhaust heat exchange element 22.
More specifically, the intake heat exchange element 21 may include a heat exchange sheet 211, which may be made of a thin paper material, introduction guide ribs 212, which may be disposed on one side of the heat exchange sheet 211 such that they are spaced apart by predetermined distances, and a frame 213 provided at an edge portion of the heat exchange sheet 211 to maintain the shape of the intake heat exchange element 21. The introduction guide ribs 212 may be divided into three sections, for example, an outdoor air intake section, an intermediate section and an outdoor air exhaust section. The outdoor air intake section and the outdoor air exhaust section may be disposed on both edges of the intermediate section, respectively. The introduction guide rib 212 of the outdoor air intake section and the outdoor air exhaust section may be bent such that it is inclined at a predetermined angle with respect to the introduction guide rib 212 of the intermediate section.
That is, the introduction guide rib 212 may be configured with an intake portion 212 a, a straight portion 212 b, and an exhaust portion 212 c. The straight portion 212 b may extend from the intake portion 212 a such that it is inclined at a predetermined angle with respect to the intake portion 212 a. The exhaust portion 212 c may further extend from an end of the straight portion 212 b such that it is inclined at a predetermined angle with respect to the straight portion 212 b.
Similar to the intake heat exchange element 21, the exhaust heat exchange element 22 may include a heat exchange sheet 221, exhaust guide ribs 222, which may be disposed on attached to one side of the heat exchange sheet 21 such that they are spaced apart by predetermined distance, and a frame 223. The exhaust guide rib 222 may also be configured with an intake portion 222 a, a straight portion 222 b and an exhaust portion 222 c. However, it is noted that the intake portion 222 a and the exhaust portion 222 c of the exhaust guide rib 222 may be respectively inclined in directions symmetric to the intake portion 212 a and the exhaust portion 212 c of the introduction guide rib 212.
As illustrated in FIGS. 2 and 3, the intake portion 212 a of the introduction guide rib 212 may be inclined such that it crosses the intake portion 222 a of the exhaust guide rib 222. Of course, the exhaust portions 212 c and 222 c may be inclined such that they cross each other in the same manner. The intake portion of the intake heat exchange element 21 and the intake portion of the exhaust heat exchange element 22 may cross each other, or the exhaust portion of the intake heat exchange element 21 and the exhaust portion of the exhaust heat exchange element 22 may cross each other.
The intermediate sections of the introduction and exhaust guide ribs 212 and 222, in which heat exchange operation may be effectively performed, may be arranged in parallel, but incoming air and outgoing air flow in opposite directions to each other, respectively, which makes it possible to increase heat exchange efficiency as much as possible.
That is, the outdoor air and the indoor air may be heat exchanged with each other substantially more or the most in the section where they pass through the straight portions 212 b and 222 b than in any other section. The heat is sufficiently exchanged between the incoming air and the outgoing air as a length of the straight portion increases. However, this inevitably leads to a decrease of flow velocity of air.
FIGS. 5 and 6 are sectional views of a velocity distribution of heat exchange gas in the heat exchange element of FIG. 4. Referring to FIGS. 5 and 6, the introduction guide rib 212 and an exhaust guide rib 222 may be provided such that they are stacked. Outdoor air is introduced along the introduction guide rib 212, and indoor air is introduced along an exhaust guide rib 222. Assuming that ribs have the shape of a quadratic prism, four surfaces of the quadratic prism may be divided into a pair of first surfaces contacting the heat exchange sheet, and a pair of second surfaces contacting the heat exchange gas directly. When the heat exchange gas flow is a laminat flow, a velocity distribution 240 of the heat exchange gas in each duct formed by the ribs may be represented as a parabolic profile because gas velocity is the highest at a center of the duct, progressively decreases far from the center, and becomes approximately 0 on the surface of the ribs.
FIG. 7 is a sectional view of heat exchange elements having ribs with irregular structural surfaces according to an embodiment. As shown in FIG. 7, the heat exchange elements are multi-stacked in a thickness direction. More specifically, FIG. 7 is a sectional view taken along line I-I′ of FIG. 5 in case that the heat exchange elements of FIG. 5 are triply multi-stacked. The ribs of FIG. 7 each have an irregular structural surface in the form of uneven portion 30 is provided on a surface of the ribs of FIG. 5 to increase surface roughness. FIG. 8 is a sectional view of a rib according to an embodiment with an irregular structural surface in the form of an uneven portion having irregular shapes arranged along a surface of the ribs 212 or 222.
Referring to FIGS. 7 and 8, the uneven portion 30, which may be arranged regularly or irregularly on side surfaces (these may be defined as “second surfaces”) of the guide rib 212 and 222 of the heat exchange element 20 according to the embodiment, is in contact with the heat exchange gas. In addition, top and bottom surface of the guide rib 212 and 222 (these may be defined as “first surfaces”) contact the heat exchange sheet.
More specifically, the uneven portion 30 may be provided with a protrusion 31 which may protrude a predetermined distance from the surface of the rib, and a recess 32 which may be recessed a predetermined depth from the surface of the ribs. The protrusion 31 and the recess 32 may have various shapes, such as a circle, a polygon, or other shape. The irregular arrangement and irregular shape of the uneven portion 30 may be more effective for inducing a turbulent flow. Further, a turbulent flow may be rapidly formed by forming the protrusion 31 and the recess 32 in various sizes and depths. Alternatively, a turbulent flow may be formed by forming a scratch or scratches on the surface of the guide rib.
FIG. 9 is a perspective view of a heat exchange element having ribs with irregular structural surfaces according to an embodiment. Here, a velocity distribution 250 of heat exchange gases flowing through each duct of the heat exchange element shows a turbulent flow type distribution in which the velocity distribution has a relatively flat profile around the center of the duct and a thickness of a boundary layer is thin, unlike the parabolic profile of FIG. 6. According to a heat exchange element having the above configuration, it may be possible to minimize duct resistance by suppressing a laminar flow and growth of a boundary layer in airflow of outdoor and indoor air passing through a heat exchanger. Therefore, heat exchange may be performed even with low flow velocity and pressure because the pressure loss in the duct may be minimized. Further, since the heat exchange gas may be introduced/exhausted smoothly at a flow velocity as low as possible, the heat exchange efficiency may be increased as well.
Embodiments disclosed herein provide a heat exchanger for a ventilating apparatus that may increase heat exchange efficiency and reduce pressure loss by changing airflow of outdoor and indoor air passing through a heat exchange element from a laminar flow to a turbulent flow.
In a heat exchanger for a ventilating apparatus, ribs coupled to a heat exchange sheet generally have smooth surfaces. This smooth surface may have no adverse effect if the flow velocity of the heat exchange gas is high enough. However, in the case that the flow velocity of gas passing through the heat exchanger is low, the smooth surface may cause a boundary layer to grow excessively generating a laminar flow. When the heat exchange gas flow is a laminar flow inside the heat exchanger, pressure loss is likely to increase at an exhaust end because the flow velocity of the gas decreases. Therefore, the heat exchange gas must be introduced at a predetermined pressure and velocity higher than an appropriate flow velocity range through an intake end for good heat exchange ultimately, which leads to the decrease of heat exchange efficiency.
Embodiments disclosed herein also provide a heat exchanger for a ventilating apparatus that may increase heat exchange efficiency by minimizing pressure loss, and thus, securing an appropriate flow velocity of heat exchange gas even under a limited supply pressure because outdoor air and indoor air passing through the heat exchanger may flow in turbulent flow type as much as possible. In one embodiment, a rib of a heat exchange element defining a heat exchange gas and guiding a flow of the heat exchange gas may include at least one first surface contacting a heat exchange sheet, and at least one second surface contacting the heat exchange gas. The second surface may be a structural surface where a recess portion, a protrusion portion, or a combination of the recess portion and the protrusion portion may be provided.
Further, the structural surface may correspond to a surface with increased surface roughness on the second surface. The surface roughness may be adjusted to a predetermined value that minimizes pressure drop and velocity drop of the heat exchange gas, which is possible by controlling a mean height of the structural surface.
Also, the mean height of the structural surface may be constant for inducing regular and smooth gas flow in a counter flow section of the heat exchange gas, for example, in a section where the rib has a straight shape. A protrusion portion or a recess portion of the structural surface may act as a turbulent flow generating portion to reduce a thickness of a boundary layer of gas in the duct from an aspect of overall view rather than its specific shape.
In another embodiment, a heat exchange element is provided that includes a plurality of heat exchange sheets which are multi-stacked, and a plurality of ribs arranged between the heat exchange sheets to constitute ducts with the heat exchange sheets. The ribs may include a structural surface including a recess portion, a protrusion portion, or a combination of the recess portion and the protrusion portion, which generates a turbulent flow in a heat exchange gas flowing through the duct. The structural surface may correspond to a surface increasing surface roughness of the second surface. Further, a mean height of the structural surface may correspond to a value that minimizes internal pressure drop of the heat exchange gas. Alternatively, a mean height of the structural surface may correspond to a value that minimizes internal flow velocity drop of the heat exchange gas.
With such a heat exchanger in which the heat exchange elements in the shape of a duct having the above rib structure are repeatedly stacked, it may be possible to make gases flow smoothly at a flow velocity as low as possible for increasing the heat exchange efficiency.
Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications ate possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

1. A rib for a heat exchange element configured to guide a flow of heat exchange gas, comprising:

at least one first surface that contacts a heat exchange sheet; and

at least one second surface that contacts the heat exchange gas, wherein the at least one second surface includes an irregular structural surface having an uneven portion.

2. The rib according to claim 1, wherein the uneven portion includes a recess portion, a protrusion portion, or a combination of a recess portion and a protrusion portion provided on the at least one second surface.

3. The rib according to claim 1, wherein a mean height of the at least one second surface corresponds to a value that minimizes pressure drop of the heat exchange gas.

4. The rib according to claim 1, wherein a mean height of the at least one second surface corresponds to a value that minimizes velocity drop of the heat exchange gas.

5. The rib according to claim 1, wherein a mean height of the at least one second surface is constant in a straight section of the rib.

6. A heat exchange element comprising the rib of claim 1.

7. A heat exchange apparatus comprising the heat exchange element of claim 6.

8. A ventilation apparatus comprising the heat exchange apparatus of claim 7.

9. A heat exchange element, comprising:

a plurality of heat exchange sheets which are multi-stacked; and

a plurality of ribs arranged between the heat exchange sheets to form ducts with the heat exchange sheets, wherein each of the plurality of ribs comprises an irregular structural surface including an uneven portion.

10. The heat exchange element according to claim 9, wherein the uneven portion includes a recess portion, a protrusion portion, or a combination of a recess portion and a protrusion portion, which generates a turbulent flow in a heat exchange gas flowing through the duct.

11. The heat exchange element according to claim 9, wherein a mean height of the irregular structural surface corresponds to a value that minimizes internal pressure drop of the heat exchange gas.

12. The heat exchange element according to claim 9, wherein a mean height of the irregular structural surface corresponds to a value that minimizes internal flow velocity drop of the heat exchange gas.

13. The heat exchange element according to claim 9, wherein a mean height of the irregular structural surface is constant in a straight section of the rib.

14. A heat exchange apparatus comprising the heat exchange element of claim 9.

15. A ventilation apparatus comprising the heat exchange apparatus of claim 14.