Heat exchangers are used to remove excess heat from a variety of applications. Some heat exchangers employ adjacent flows of hot and cold heat exchange fluids through channels or passages to transfer heat from the hot fluid to the cold fluid. Some heat exchanger configurations include flat tubes through which the fluids flow. Fins may be provided within and/or outside the tubes to increase the surface area available for heat transfer. A headering system is provided to introduce heat exchange fluids into and withdraw the fluids from the body of the heat exchanger.
A heat exchanger with headering system is provided. The heat exchanger includes a body that extends between first and second headers. The central span of the body includes two sets of channels arranged in a checkerboard pattern to provide efficient heat transfer between heat transfer fluids in each set. End portions of the body, within the headers, include offsets that transition the sets of channels from a vertical linear alignment to the checkerboard pattern. This configuration allows heat exchange fluids to be introduced into the appropriate sets of channels through the headers efficiently and with less complexity.
In one embodiment, a heat exchanger includes a body comprising a longitudinally extending central span and first and second end portions. First and second headers are attached to the end portions of the body. Each header includes a housing and first and second chambers disposed within the housing in longitudinal alignment with the central span. Ports for inlet and outlet of fluid are formed in at least one header.
The body of the heat exchanger includes first and second sets of a plurality of channels within the body, each channel having open ends located at the first and second end portions. Along the central span of the body, the channels of the first set and the channels of the second set form a checkerboard pattern in cross section, with walls of each channel of one of the sets shared with walls of adjacent channels of the other of the sets. Within the first and second end portions of the body, the channels include offsets that transition the channels from the checkerboard pattern to a configuration in which the open ends of the channels of each set alternate in linearly alignment in cross section. Also within the first and second end portions, the channels of one set extend longitudinally beyond the channels of the other set so that the open ends of one set terminate at one of the chambers and the open ends of the other set terminate at the other of the chambers.
A method of manufacturing the heat exchanger is provided. In one embodiment, the method includes extruding a material into a longitudinally extending body piece, with a plurality of aligned channels extending through the body. The longitudinally extending body piece is cut into a plurality of segments. Each segment is bent at opposite ends within a plane through the aligned rows to form an offset at each end. The segments are stacked into a stack with the offsets of each segment arranged in alternating directions, the plurality of channels aligned in parallel within a central span. The segments in the stack are joined to form an integral body. Sections of the end portions of alternating planes of channels are removed. Headers are attached at each end of the body.
The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which:
One embodiment of a heat exchanger with headering system is illustrated in
Additionally, heat exchange fluid can be introduced in a counterflow pattern through adjacent channels. That is, fluid flow through any one channel 24a within the central span 18 is counter to, or in the opposite direction of fluid flow through the abutting channels 24b. Because the hotter fluid and the cooler fluid are flowing in counter or opposite directions, the heat transfer can be more efficient than if the hotter and cooler fluids were flowing in the same direction.
Referring also to
Within the first and second end portions 20 of the body 12, the channels 24 transition from the checkerboard pattern of the central span 18 to a configuration that allows the heat exchange fluids to be introduced into the appropriate channels through the headers 14, 16 with less complexity. More particularly, the planes or columns 34 of channels 24 are formed with alternating in-plane offsets 30 that transition the channels from the checkerboard pattern of the central span to a configuration in which the channels 24a, 24b of each set are linearly aligned in cross section in rows 32′, 32″ orthogonal to the columns 34. See also
Adjacent planes or columns 34 of channels have offsets 30 that alternate direction, best illustrated in
An analogous arrangement occurs to transition the channels from the checkerboard pattern to a linear alignment in the second header 16.
In operation, a hotter heat exchange fluid is introduced into, for example, the first set of the channels 24a through the inlet chamber 46 of the first header 14, flows the length of the central span 18, and is withdrawn through the outlet chamber of the second header 16. A cooler heat exchange fluid is introduced into the second set of the channels 24b through the inlet chamber of the second header 16, flows the length of the central span counter to the hotter fluid flow, and is withdrawn through the outlet chamber 44 of the first header 14. Along the central span 18, the hotter fluid is in heat exchange relationship with the cooler fluid through all four walls of each channel. It will be appreciated that which set of channels 24a, 24b receives the hotter heat exchange fluid and which the cooler heat exchange fluid is determined by the application. Similarly, which chambers are used for fluid input and which for fluid output are also determined by the application.
Any suitable heat exchange fluid, such as water or an oil, can be used. The hotter fluid and the cooler fluid can be the same fluid, or they can be different fluids. Each fluid can be in either the liquid or the gaseous state. The phase of the fluid can transform from gaseous to liquid or from liquid to gaseous within the channels if desired, depending on the heat transfer application.
The heat exchanger with headering system can be manufactured in any suitable manner. In one example, the heat exchanger can be manufactured as follows. A plane or column 34 of channels 24 is formed as an extrusion. Generally, a suitable material, such as a metal, is extruded into a longitudinally extending body piece with a plurality of channels in a linear alignment extending through the body piece. Forming each plane of channels as a unitary extrusion aids in minimizing leakage from the heat exchanger during operation. The extrusion is cut into a plurality of individual segments 62 each of an appropriate length. See
Each extruded segment 62 is bent at each end within the plane of the channels to provide the offset 30. See
The plurality of segments 62 are then stacked up, preferably with the edges 64 along the central span 18 of each segment in alignment, and with the offsets 30′, 30″ alternating by column 34, as illustrated in
The header housings 40 are formed in any suitable manner. For example, for each housing, the tube sheet 42 and two sections 72, 74 to define the chambers 44, 46 are cut from a sheet of suitable metal. An opening 76 sized to receive the stack of extrusions is cut in the inner chamber section 72. Openings for inlet and outlet ports 48 are cut in each chamber section. Slots 78 sized to support rows of the extended channels 24b are cut in the tube sheet. The chamber sections 72, 74 are formed by bending into the shape of the housing.
The stack 66 of segments 62 is inserted at each end portion 20 into the opening 76 in the innermost chamber section 72 of the housing. The extended channels 24a are inserted into or adjacent the slots 78 of the tube sheet 24. The outermost chamber section 74 of the housing is placed against the partition wall 42. See
In another embodiment, a two-pass heat exchanger 110 with headering system is provided, illustrated in
More particularly, the header 114 includes an outer chamber 144 and an inner chamber 146. The outer chamber 144 is further partitioned by an outer divider 148 into an outer inlet chamber 152 and an outer outlet chamber 154 for a first heat exchange fluid. The outer divider 148 is attached to tube sheet 142 at, for example, a midpoint between extended channels 124b and to inner walls of the housing 140. The outer inlet chamber 152 includes an inlet port 156, and the outer outlet chamber 154 includes an outlet port 158.
The inner chamber 146 is partitioned into an inner inlet chamber 164 and an inner outlet chamber 166 by an inner divider 162 located between channels 124 and orthogonal to the outer divider 148. The inner divider 162 can be formed by, for example, leaving a rib when removing the end portions of every other row of channels 124a, as described above. Side dividers 163 can be formed on inner walls of the housing 140 to join with edges of the inner divider 162 to complete the partitioning of the inner chamber 146. The inner inlet chamber 164 includes an inlet port 168, and the inner outlet chamber 166 includes an outlet port 172.
In operation, a first heat exchange fluid, indicated schematically by a dashed line 174 in
Suitable materials for the heat exchanger body and headers include metals such as aluminum, an aluminum alloy, copper, a copper alloy, steel, stainless steel, titanium, or a titanium alloy, although other metals can be used. Plastic materials can also be used.
The present heat exchanger can be readily manufactured. The heat exchanger obviates the need for complicated fin geometries to increase the surface area within rows, as in prior art heat exchangers. The heat exchange fluid(s) can be introduced into the channels with less complexity.
It will be appreciated that the reference to rows and columns is for convenience of description and does not refer to an orientation of the heat exchanger during manufacture or in operation. Although the channels are shown with square cross sections, other cross sectional shapes are possible, such as rectangular, hexagonal. The segments or individual rows of channels can be formed in other ways, such as by forming a sheet or sheets of metal into the appropriate shapes. The invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.