MICRO-PORT SHELL AND TUBE HEAT EXCHANGER
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to a heat exchanger and, more
particularly, to a shell and tube heat exchanger.
[0002] Heating and cooling systems, such as HVAC and refrigeration systems,
typically employ various types of heat exchangers to provide heating and cooling. These heat
exchangers often include shell and tube or tube in tube heat exchangers. In each case, heat
transfer usually occurs between fluids that are directed to flow in close proximity to one
another and in a closely coupled heat transfer interaction with one another.
[0003] For example, in a shell and tube heat exchanger, a shell forms an exterior
surface of a vessel into which refrigerant vapor is introduced. Water is then directed through
water tubes extending through the vessel such that heat transfer occurs between the
refrigerant and the water. In another example, refrigerant may be directed through the tubes,
while water or other heat transfer media, such as ethylene glycol or propylene glycol, is
directed through the space between the tubes and the heat exchanger outer shell.
[0004] Shell and tube heat exchangers typically represent about 50% of the cost of
water cooled chillers and often determine the required refrigerant amount and the unit
footprint, both of which tend to change over time in response to constantly rising energy
efficiency demands that typically increase the size limitations and cost of shell and tube heat
exchangers.
BRIEF DESCRIPTION OF THE INVENTION
[0005] According to one aspect of the invention, a tubular body of a heat exchanger is
provided. The heat exchanger is adapted to transmit a first fluid through an interior, the
tubular body being receptive of a second fluid, whereby heat transfer occurs between the first
and second fluids. The tubular body extends longitudinally through the interior of the heat
exchanger, has a non-circular cross-section, and is formed to define microchannels extending
longitudinally through the tubular body through which the second fluid is transmitted.
[0006] According to another aspect of the invention, a heat exchanger is provided and
includes a shell defining an interior, manifolds coupled to the shell by which a first fluid is
communicated within the interior, and a tubular body disposed within the interior to transmit
a second fluid therethrough, whereby heat transfer occurs between the first and second fluids.
The tubular body extends longitudinally through the interior, has a non-circular cross-section,
and is formed to define microchannels extending longitudinally through the tubular body
through which the second fluid is transmitted.
[0007] According to yet another aspect of the invention, a heat exchanger is provided
and includes a shell defining an interior, manifolds coupled to the shell by which a first fluid
is communicated within the interior, and first and second tubular bodies to transmit a second
fluid through the interior, whereby heat transfer occurs between the first and second fluids,
wherein each of the first and second tubular bodies extends longitudinally through the interior
of the heat exchanger, has a non-circular cross-section, and is formed to define microchannels
extending longitudinally through the tubular body through which the second fluid is
transmitted.
[0008] These and other advantages and features will become more apparent from the
following description taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The subject matter which is regarded as the invention is particularly pointed
out and distinctly claimed in the claims at the conclusion of the specification. The foregoing
and other features, and advantages of the invention are apparent from the following detailed
description taken in conjunction with the accompanying drawings in which:
[0010] FIG. 1 is a cross-sectional view of a heat exchanger;
[0011] FIG. 2 is a perspective view of a portion of a tubular member of the heat
exchanger of FIG. 1; and
[0012] FIG. 3 is a perspective view of a portion of a tubular member of the heat
exchanger of FIG. 1.
[0013] The detailed description explains embodiments of the invention, together with
advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Heat exchanger effectiveness has become one of the foremost driving forces in
meeting constantly increasing overall system efficiency demands and reducing carbon
dioxide emissions, as prescribed by the industry requirements and governmental regulations.
Superior heat exchanger performance ultimately leads to footprint, weight and material
content reductions.
[0015] In accordance with aspects of the present invention, the heat exchanger
construction is a microchannel heat exchanger ("MCHX") for gas-to-liquid, liquid-to-liquid
and gas-to-gas applications. In the gas-to-liquid case, for example, air is directed outside of
the heat exchanger tubes and refrigerant or other coolant is directed through the tubes. The
MCHX design allows for more compact configurations, enhanced performance, refrigerant
charge reduction and improved structural rigidity.
[0016] With reference to FIG. 1, a heat exchanger 10 is provided. The heat exchanger
10 includes a shell 20 defining an interior 2 1 therein, inlet/outlet manifolds 30, 3 1 fluidly
coupled to the shell 20, by which a first fluid 32 is communicated with the interior 2 1 of the
shell 20, and a tubular body 40. The tubular body 40 is configured to transmit a second fluid
4 1 through the interior 2 1 of the shell 20, in particular, within tubular bodies 40. As such,
heat transfer occurs between the first and second fluids 32 and 41.
[0017] More specifically, the tubular body 40 extends longitudinally through the
interior 2 1 of the shell 20 in one or more passes, has a non-circular cross-section 42, and is
formed to define microchannels 50. The non-circular cross-section 42 may be elongated,
oval, or rectangular. The microchannels 50 are arranged in a side-by- side configuration
within the non-circular cross-section 42 and are bored longitudinally through the tubular body
40. The microchannels 50 provide pathways within the tubular body 40 through which the
second fluid 4 1 is transmitted. For example, as shown in FIG. 1, the non-circular crosssection
42 is predominantly a rectangular shape with rounded corners, the microchannels 50
are aligned along a center-line thereof. If the microchannels 50 are small enough relative to
the tubular body 40, the microchannels 50 may be arrayed in either an in-line or staggered
matrix arrangement along the center-line of the cross-section 42. It has to be understood that
although the microchannels 50 are shown as having a circular cross-section, they may have
any non-circular or other polygonal cross-sectional shape, including but not limited to
rectangular, trapezoidal, or triangular shapes, each of which are within the scope of this
invention.
[0018] In accordance with certain embodiments, water or glycol may be directed
through the microchannels 50 as the second fluid 41, with refrigerant, such as low pressure
refrigerants R134a or R1234yf, provided in the interior 2 1 as the first fluid 32 for condensing
or evaporating. Alternatively, refrigerant, such as high pressure refrigerants R410A or C0 2,
may be directed through the microchannels 50 as the second fluid 41, while coolant is
directed through the interior 2 1 as the first fluid 32.
[0019] The tubular body 40 may include copper as a base metal with aluminum
and/or plastic added. Alternatively, the tubular body 40 may be formed of aluminum, plastic,
or other materials. That is, although the tubular body 40 can be made from copper material,
less expensive aluminum or plastic material would achieve further cost and weight savings.
Where aluminum is used, a brazing furnace operation can be employed for the production of
the tubular body 40 or a bundle thereof for later insertion into the shell 20. With plastic
materials, diffusion bonding or any other known method can be used to rigidly assemble the
tubular body 40 or the bundle thereof.
[0020] With reference to FIGS. 2 and 3, the tubular body 40 includes an exterior
surface 43 to which a coating material is applied in order to promote one of filmwise and
dropwise condensation and to improve heat transfer characteristics. Tubular body 40 also
includes interior surfaces 44. The exterior surface 43 and the interior surfaces 44 may include
one or more of porous features 60, indentations 61, grooves 62 and fins 63. The porous
features 60 may be formed by metal being sprayed onto the exterior and/or interior surfaces
43, 44. Indentations 6 1 can be made to promote nucleation. The grooves 62 and the fins 63
can be integrated in the exterior surface 43 or interior surfaces 44 of the tubular body 40
during extrusion processes or secondary operations, and can be longitudinally or laterally
oriented relative to the tubular body 40.
[0021] Referring back to FIG. 1, it is to be understood that the tubular body 40 may
be provided as a plurality of tubular bodies 40, with each tubular body 40 being constructed
substantially as described above but not necessarily similarly with respect to one another. For
example, first and second tubular bodies 400, 401 may each have an elongate cross-section
42 and may be oriented such that the elongation is aligned substantially vertically or such that
the elongation of one or both is angled with respect to the vertical direction. Where both are
angled, the angling may be similar or different. In any case, the vertical or nearly vertical
orientation aids in drainage of condensate.
[0022] Similarly, first and second tubular bodies 400, 401 may each include exterior
and interior surfaces 43, 44 having different porous features 60, indentations 61, grooves 62
and fins 63. The first and second tubular bodies 400, 401 may have similar or different sizes.
Further, distances between the first and second tubular bodies 400, 401 and between the
second tubular body 401 and a third tubular body 402 may be similar or different. Similarly,
distances between microchannels within tubular bodies 400, 401 and 402 may be different,
depending on the location of each tubular body within the shell 20. In some cases, the relative
position of tubular bodies 40 may be set so as to decrease a footprint of the heat exchanger 10
and/or to prevent or reduce inundation.
[0023] While the invention has been described in detail in connection with only a
limited number of embodiments, it should be readily understood that the invention is not
limited to such disclosed embodiments. Rather, the invention can be modified to incorporate
any number of variations, alterations, substitutions or equivalent arrangements not heretofore
described, but which are commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been described, it is to be
understood that aspects of the invention may include only some of the described
embodiments. Accordingly, the invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended claims.

CLAIMS:
1. A tubular body of a heat exchanger, the heat exchanger adapted to transmit a
first fluid through an interior, the tubular body receptive of a second fluid, whereby heat
transfer occurs between the first and second fluids, wherein the tubular body:
extends longitudinally through the interior of the heat exchanger,
has a non-circular cross-section, and
is formed to define microchannels extending longitudinally through the tubular body
through which the second fluid is transmitted.
2. The tubular body according to claim 1, comprising copper alloy, aluminum
alloy or plastic.
3. The tubular body according to claim 1, comprising a coating material applied
to an exterior surface thereof, which promotes one of filmwise and dropwise condensation.
4. The tubular body according to claim 1, wherein the first fluid comprises
refrigerant and the second fluid comprises water or glycol solution.
5. The tubular body according to claim 1, wherein the first fluid comprises water
or glycol solution and the second fluid comprises refrigerant.
6. The tubular body according to claim 1, having an elongate cross-section, the
microchannels being defined in an elongate arrangement along the elongate cross-section.
7. The tubular body according to claim 1, wherein any one or more of the
microchannels have a circular cross-section.
8. The tubular body according to claim 1, wherein any one or more of the
microchannels have a non-circular or polygonal cross-sectional shape.
9. The tubular body according to claim 1, further comprising:
one or more of porous features, indentations, grooves and fins on at least one of an
exterior surface and an interior surface thereof.
10. A heat exchanger, comprising:
a shell defining an interior;
manifolds coupled to the shell by which a first fluid is communicated with the
interior; and
a tubular body disposed within the interior to transmit a second fluid therethrough,
whereby heat transfer occurs between the first and second fluids, the tubular body:
extending longitudinally through the interior,
having a non-circular cross-section, and
being formed to define microchannels extending longitudinally through the tubular
body through which the second fluid is transmitted.
11. The heat exchanger according to claim 10, wherein the tubular body comprises
copper alloy, aluminum alloy or plastic.
12. The heat exchanger according to claim 10, wherein a coating material is
applied to an exterior surface of the tubular body to promote one of filmwise and dropwise
condensation.
13. The heat exchanger according to claim 10, wherein the first fluid comprises
water or glycol solution and the second fluid comprises refrigerant.
14. The heat exchanger according to claim 10, wherein the first fluid comprises
refrigerant and the second fluid comprises water or glycol solution.
15. The heat exchanger according to claim 10, wherein the tubular body has an
elongate cross-section, the microchannels being defined in an elongate arrangement along the
elongate cross-section.
16. The heat exchanger according to claim 10, wherein any one or more of the
microchannels have a circular cross-section..
17. The heat exchanger according to claim 10, wherein any one or more of the
microchannels have a non-circular or polygonal cross-sectional shape.
18. The heat exchanger according to claim 10, wherein the tubular body
comprises:
one or more of porous features, indentations, grooves and fins formed on at least one
of an interior surface and exterior surface thereof.
19. A heat exchanger, comprising:
a shell defining an interior;
manifolds coupled to the shell by which a first fluid is communicated with the
interior; and
first and second tubular bodies to transmit a second fluid through the interior whereby
heat transfer occurs between the first and second fluids, wherein each of the first and second
tubular bodies:
extends longitudinally through the interior of the heat exchanger,
has a non-circular cross-section, and
is formed to define microchannels extending longitudinally through the tubular body
through which the second fluid is transmitted.
20. The heat exchanger according to claim 19, wherein the first and second
tubular bodies each have an elongate cross-section and are aligned substantially vertically
relative to each other.
21. The heat exchanger according to claim 20, wherein the first and second
tubular bodies are disposed at different angles relative to each other.
22. The heat exchanger according to claim 19, wherein the first and second
tubular bodies each comprise microchannels of different size and cross-sectional shape.
23. The heat exchanger according to claim 22, wherein the cross-sectional shape is
polygonal or non-circular.
24. The heat exchanger according to claim 19, wherein the first and second
tubular bodies each comprise one or more porosities, indentations, grooves and fins on at
least one of an exterior and interior surface thereof.
25. The heat exchanger according to claim 19, wherein the first and second
tubular bodies have different sizes.
26. The heat exchanger according to claim 19, wherein the spacing between
microchannels disposed in the first tubular body is different from the spacing between
microchannels disposed in the second tubular body.
27. The heat exchanger according to claim 19, comprising a plurality of tubular
bodies, wherein the tubular bodies are disposed at different distances from each other or at
different angles relative to each other.