Patent Application
20170108289
The present subject matter relates generally to heat exchangers, such as heat exchangers for refrigerator appliances, and methods for forming heat exchangers.
Refrigerator appliances generally include sealed systems for cooling chilled chambers of the refrigerator appliance. During operation of the sealed system, a compressor generates compressed refrigerant. The compressed refrigerant flows to a condenser where the refrigerant is condensed into a liquid and is sent to an expansion device. The expansion device reduces a pressure of the refrigerant before the refrigerant enters into an evaporator as a combination of liquid and vapor. The refrigerant exits the evaporator as vapor and is transported to the compressor via a suction line. Refrigerant within the evaporator absorbs heat from the chilled chambers.
Various heat exchangers are available for use in refrigerator appliances. Certain refrigerator appliances include tube fin heat exchangers, and tube fin heat exchangers may include vortex generators. The vortex generators are typically a series of winglets mounted or punched into the fins. The winglets form counter-rotating longitudinal air vortices in a flow path direction of the refrigerant that increases air mixing and thus improves heat transfer. However, tube fin heat exchangers can be expensive relative to alternative heat exchangers.
Spine fin heat exchangers include spine fin coils wrapped about a conduit. The spine fin coils can facilitate heat transfer between refrigerant within the conduit and ambient atmosphere about the spine fin heat exchanger. Spine fin heat exchangers are generally less expensive than comparable tube fin heat exchangers.
Accordingly, a spine fin heat exchanger with vortex generators would be useful. In particular, a spine fin heat exchanger with features for generating counter-rotating longitudinal air vortices in a flow path direction of refrigerant within the heat exchanger to increase air mixing and improve heat transfer would be useful.
The present subject matter provides a heat exchanger with a spine fin strip wrapped onto a conduit in a helical pattern. A first plurality of spine fins of the spine fin strip extends from a base of the spine fin strip, and a second plurality of spine fins of the spine fin strip is bent relative to the spine fins of the first plurality of spine fins. A related method for forming a heat exchanger is also provided. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.
In a first exemplary embodiment, a method for forming a heat exchanger is provided. The method includes cutting a plurality of spine fins into a sheet of metal, bending a subset of the plurality of spine fins, folding the sheet of metal to form a spine fin strip such that the plurality of spine fins extend from a base of the spine fin strip, and wrapping the spine fin strip onto a conduit in a helical pattern at an outer surface of the conduit such that the plurality of spine fins includes spine fins that extend radially away from the outer surface of the conduit and also includes spine fins that are bent relative to the radially extending spine fins.
In a second exemplary embodiment, a heat exchanger is provided. The heat exchanger includes a conduit having an outer surface. A spine fin strip is wrapped onto the conduit in a helical pattern at the outer surface of the conduit. The spine fin strip includes a base positioned at the outer surface of the conduit. A first plurality of spine fins extends radially from the base and away from the outer surface of the conduit. A second plurality of spine fins is bent relative to the spine fins of the first plurality of spine fins. The base, the spine fins of the first plurality of spine fins and the spine fins of the first plurality of spine fins are formed from a common piece of sheet metal.
In a third exemplary embodiment, a heat exchanger is provided. The heat exchanger includes a conduit having an outer surface. A spine fin strip is wrapped onto the conduit in a helical pattern at the outer surface of the conduit. The spine fin strip includes a base positioned at the outer surface of the conduit. A first plurality of spine fins is mounted to the base. Each spine fin of the first plurality of spine fins defines an angle, α, with the outer surface of the conduit proximate the first plurality of spine fins. α is about ninety degrees. A second plurality of spine fins is mounted to the base. Each spine fin of the second plurality of spine fins defines an angle, β, with the outer surface of the conduit proximate the second plurality of spine fins. β is no greater than seventy degrees. The base, the spine fins of the first plurality of spine fins and the spine fins of the first plurality of spine fins are formed from a common piece of sheet metal.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
In the exemplary embodiment shown in
Within refrigeration system 60, refrigerant flows into compressor 64, which operates to increase the pressure of the refrigerant. This compression of the refrigerant raises its temperature, which is lowered by passing the refrigerant through condenser 66. Within condenser 66, heat exchange with ambient air takes place so as to cool the refrigerant. A condenser fan 72 is used to pull air across condenser 66, as illustrated by arrows AC, so as to provide forced convection for a more rapid and efficient heat exchange between the refrigerant within condenser 66 and the ambient air. Thus, as will be understood by those skilled in the art, increasing air flow across condenser 66 can, e.g., increase the efficiency of condenser 66 by improving cooling of the refrigerant contained therein.
An expansion device (e.g., a valve, capillary tube, or other restriction device) 68 receives refrigerant from condenser 66. From expansion device 68, the refrigerant enters evaporator 70. Upon exiting expansion device 68 and entering evaporator 70, the refrigerant drops in pressure. Due to the pressure drop and/or phase change of the refrigerant, evaporator 70 is cool relative to compartments 14 and 18 of refrigerator appliance 10. As such, cooled air is produced and refrigerates compartments 14 and 18 of refrigerator appliance 10. Thus, evaporator 70 is a type of heat exchanger which transfers heat from air passing over evaporator 70 to refrigerant flowing through evaporator 70. An evaporator fan 74 is used to pull air across evaporator 70 and circulated air within compartments 14 and 18 of refrigerator appliance 10.
Collectively, the vapor compression cycle components in a refrigeration circuit, associated fans, and associated compartments are sometimes referred to as a sealed refrigeration system operable to force cold air through compartments 14, 18 (
As may be seen in
Heat exchanger 100 also includes a spine fin strip or assembly 120. Spine fin assembly 120 is disposed or positioned on or at outer surface 112 of conduit 110. In particular, spine fin assembly 120 is wrapped about conduit 110 such that spine fin assembly 120 is mounted to conduit 110 at outer surface 112 of conduit 110. Thus, spine fin assembly 120 may have a helical shape, e.g., when wound about conduit 110. Spine fin assembly 120 includes a base 122, a plurality of first spine fins 124 and a plurality of second spine fins 126. Base 122 is positioned on conduit 110 at outer surface 112 of conduit 110, and first spine fins 124 and second spine fins 126 are mounted to base 122 and wound about conduit 110, e.g., such that first spine fins 124 extend along the radial direction R from base 122 and second spine fins 126 are bent relative to first spine fins 124.
Spine fin assembly 120 may be constructed of or with any suitable material. As an example, spine fin assembly 120 may be constructed of or with a metal, such as copper or aluminum. In particular, spine fin assembly 120 may be constructed of or with a single, continuous sheet of material, such as a sheet of aluminum or copper. Thus, base 122, first spine fins 124 and second spine fins 126 may be defined by or formed with the single, continuous sheet of material.
As may be seen in
Second spine fins 142 may also be distributed in any suitable manner on conduit 110 and/or base 131. For example, the spine fins of second spine fins 142 may be bent such that second spine fins 142 are distributed in a helical pattern (shown with arrows H) within and/or between windings of spine fin assembly 120. Bending second spine fins 126 relative to first spine fins 124 (e.g., and distributing second spine fins 126 in the helical pattern H) may assist with forming vortex generators on spine fin assembly 120. Without wishing to be bound to any particular theory, the bent second spine fins 126 may enhance heat transfer of heat exchanger 100 with ambient air about heat exchanger 100 by creating turbulent airflow about first spine fins 124 and/or directing the turbulent airflow into a wake region to reduce recirculation flow. Thus, an efficiently of a system associated with heat exchanger 100 may be improved.
It should be understood that second spine fins 126 need not be bent at a junction between second spine fins 126 and base 122 in certain exemplary embodiments. For example, second spine fins 126 may be bent such that one portion of each spine fin of second spine fins 126 extends the radial direction R from base 122 and another portion (i.e., a winglet) of each spine fin of second spine fins 126 is bent relative to first spine fins 124. Thus, second spine fins 126 may be bent away from base 122 in certain exemplary embodiments to form vortex generators.
As may be seen in
Turning now to
Turning now to
Second spine fins 142 at first side portion 134 of the sheet of material 132 may be offset from second spine fins 142 at second side portion 136 of the sheet of material 132. For example, each second spine fin 142 at first side portion 134 of the sheet of material 132 may be positioned between a respective pair of second spine fins 142 at second side portion 136 of the sheet of material 132. The selection of the gaps between teeth 152 of combs 150 and/or the positioned of teeth 152 of combs at first and second side portion 134, 136 of the sheet of material 132 may assist with positioning second spine fins 142 in a desired pattern, as discussed in greater detail below.
As shown in
Turning now to
As discussed above, second spine fins 142 are bent relative to first spine fins 140. In particular, each spine fin of first spine fins 140 defines an angle, a, with outer surface 112 of conduit 110 (e.g., or base 131) proximate first spine fins 140. The angle α may be about ninety degrees. As used herein, the term “about” means within ten degrees of the stated angle when used in the context of angles. Conversely, each spine fin of second spine fins 142 defines an angle, β, with outer surface 112 of conduit 110 (e.g., or base 131) proximate second spine fins 142. The angle β may be no greater than seventy degrees. As another example, the angle β may be about forty-five degrees.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
