Evaporator Coil Insert

This application is a continuation of U.S. patent application Ser. No. 18/516,223, now U.S. published patent application no. 2024/0085070, entitled “EVAPORATOR COIL INSERT”, which is a continuation of U.S. patent application Ser. No. 17/225,415 filed on Apr. 8, 2021, now U.S. Pat. No. 11,885,539, issued on Jan. 30, 2024 by Xi Sun, entitled “EVAPORATOR COIL INSERT,” which is a divisional of U.S. patent application Ser. No. 16/170,885 filed Oct. 25, 2018, now U.S. Pat. No. 11,009,271, issued on May 18, 2021, by Xi Sun, entitled “EVAPORATOR COIL INSERT,” each of which are hereby incorporated by reference in their entirety.

This disclosure generally relates to an insert, and more specifically to an insert for an evaporator coil.

Certain refrigerants used in heating, ventilation, and air conditioning (HVAC) systems raise environmental concerns. For example, Class I and II refrigerants have substances that may deplete the ozone layer. Due to these environmental concerns, legislation is phasing out certain refrigerants and recommending other natural, non-toxic refrigerants such as hydrocarbon that are free of ozone-depleting properties.

According to an embodiment, an apparatus includes an insert for an evaporator coil. The insert is located within the evaporator coil. The insert for the evaporator coil reduces refrigerant charge in the evaporator coil and causes refrigerant flowing through the evaporator coil to change direction.

According to another embodiment, a system includes an evaporator coil and an insert for the evaporator coil. The insert is located within the evaporator coil. The insert for the evaporator coil reduces refrigerant charge in the evaporator coil and causes refrigerant flowing through the evaporator coil to change direction.

According to yet another embodiment, a method includes locating an insert within an evaporator coil. The insert for the evaporator coil reduces refrigerant charge in the evaporator coil and causes refrigerant flowing through the evaporator coil to change direction.

The insert for the evaporator coil described in this disclosure may provide one or more of the following technical advantages. The insert reduces the volume within the evaporator coil by up to 70 percent, which may reduce the charge of refrigerant (e.g., hydrocarbon refrigerant) for the refrigerant system. The evaporator coil insert may increase the velocity of the refrigerant in the evaporator coil, which may improve oil return under certain conditions (e.g., a low temperature, part load condition). The evaporator coil insert may cause the refrigerant in its liquid and vapor form to change direction as it flows through the evaporator coil, which may increase the Reynolds (Re) number. The Re number is a dimensionless value that measures the ratio of inertial forces to viscous forces and describes the degree of turbulent flow. A low Re number indicates smooth, constant, fluid motion, whereas a high Re number indicates turbulent flow. Increasing the Re number may improve the efficiency of the refrigerant system. The evaporator coil insert is adaptable since it can be cut for any length of coil and sized to fit into any coil opening. Manufacturing the evaporator coil insert may be cost efficient since it is manufactured separate from the evaporator coil. The evaporator coil insert may be manufactured using existing production tooling.

The evaporator coil insert reduces the volume within the evaporator coil, which reduces the volume of refrigerant that can be received by the evaporator. The reduced volume of refrigerant may result in reduced cost of refrigerant. The evaporator coil insert is versatile in that it may be used by different evaporator units. The evaporator coil insert may reduce the refrigerant charge for any refrigerant system, which may assist the refrigerant system in satisfying refrigerant charge limits.

The size of evaporator coil insert may be optimized for gas regions. For example, the size of the evaporator coil insert may be larger in regions of the evaporator coil (e.g., an inlet of the evaporator coil) that will experience a flow of refrigerant in its liquid form and smaller in regions of the evaporator coil (e.g., an outlet of the evaporator coil) that will experience a flow of refrigerant in its vapor form. The evaporator coil insert may include different materials. For example, the core of the evaporator coil insert may be made of copper and the support legs for the evaporator coil insert may be made of a combination of copper and Teflon. The number of support legs for the evaporator coil insert may vary depending on the application. The core of the evaporator coil insert may be solid or hollow to balance objectives. For example, the core may be solid to reduce the volume of refrigerant flow in the evaporator coil. As another example, the core of the evaporator coil insert may be hollow to reduce cost and weight of the evaporator coil insert.

Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages.

Certain refrigerant systems use evaporators to convert refrigerant from its liquid form into a vapor. Legislation may require that the refrigerant system maintain a certain refrigerant charge. For example, for hydrocarbon (e.g., R290) refrigerants, legislation may limit the amount of charge to 150 grams per system. This disclosure includes an insert for an evaporator coil of a refrigerant system that reduces refrigerant charge of the system by reducing the volume in the evaporator coil.

show example inserts for an evaporator coil of a refrigerant system.shows an example system for an evaporator coil insert andshows an example method for installing the evaporator coil insert ofinto the evaporator coil.show different types of inserts for the evaporator coil andshows example dimensions for an evaporator coil insert.shows example reductions in refrigerant charge based on the size of the evaporator coil insert relative to the size of the evaporator coil.

illustrates an example systemfor an evaporator coil insert. Systemincludes evaporator coiland insert. Evaporator coilmay be part of an air conditioner or heat pump of a refrigerant system. Evaporator coilmay be located within an air handler of the refrigerant system and/or attached to a furnace of the refrigerant system. Evaporator coilmay be used in commercial and/or residential refrigerant systems. Evaporator coilholds refrigerant (e.g., hydrocarbon refrigerant). The refrigerant within evaporator coilmay change from a liquid to a vapor as it absorbs heat from the surrounding air. Evaporator coilmay be any size suitable for refrigerant flow in system. For example, an outer diameter of evaporator coilmay be in the range of ⅜ inch to ⅝ inch and a length of each evaporator coilmay range from 4 inches to 30 inches. Evaporator coilmay include one or more bends to accommodate one or more changes in direction. Evaporator coilmay include one or more fittings (e.g., a U-shaped fitting) to accommodate one or more changes in direction.

Insertof evaporator coilis any physical form that can be inserted into evaporator coil. Insertmay be made of copper, steel, aluminum, a polytetrafluoroethylene (PTFE) based formula such as Teflon, rubber, any other suitable material, or a combination of the preceding. Insertcomprises a coreand support legs. Coremay be any suitable shape. For example, a cross-sectional area of coremay be a square, a rectangle, a circle, an oval, or a cluster of shapes (e.g., circles). In the illustrated embodiment of, coreis a solid core with a cross-sectional area in the shape of a square that has four equal sides.

Inserthas a first endand a second end, wherein coreincludes a first end (e.g., an upstream end) of the insert and a second end (e.g., a downstream end) that opposite to the first end downstream of the insert. Coreis twisted along its length such that each side (e.g., side) of first endis rotated 90 degrees from the corresponding side (e.g., side) of second end, wherein refrigerant may flow from first end(upstream) to second end(downstream). The twisted shape of corewithin evaporator coilredirects refrigerant within evaporator coil, which causes the refrigerant flowing through evaporator coilto change direction. This change in direction may increase the turbulence of the refrigerant in evaporator coil. For insertswith solid cores, the refrigerant flows in its liquid and/or vapor form between the outer surface of solid coreand an inner surface of evaporator coil. For insertswith hollow cores, the refrigerant flows in its liquid and/or vapor form within solid coreand between the outer surface of hollow coreand the inner surface of evaporator coil.

Insertincludes four support legs. Each support legis attached to a sideof coreof insert. For example, support legmay be attached to first endof insertat a midpoint of side. Each support legmay contact an inner surface of evaporator coil. Support legsof insertare used to stabilize insertwithin evaporator coil. Support legsmay secure insertwithin evaporator coil. For example, an end of support legmay be brazed (i.e., soldered) to an inner surface of evaporator coil. As another example, an end of support legmay be made of a flexible material such as Teflon or rubber and secured within evaporator coilusing friction, compression, or a combination thereof. In some embodiments, support legmay be a spring that presses against the inner surface of evaporator coil. Support legmay be located at the end of evaporator coilor inside evaporator coil.

Insertof evaporator coilreduces the volume within evaporator coil, which reduces the refrigerant charge within evaporator coil. Refrigerant charge is a charge required for stable operation of a refrigerant system (e.g., an HVAC unit) under certain operating conditions. Refrigerant charge may be measured in grams per circuit. For example, a charge limit for a hydrocarbon refrigerant may be 150 grams per system.

In operation, coreof insertis twisted 90 degrees and placed within evaporator coilof system. Support legis attached to each end of coreon each side of core. Each support legis brazed to an inner surface of evaporator coilto stabilize insertwithin evaporator coil. As such, insertof systemofreduces refrigerant charge in evaporator coilby reducing the volume within evaporator coil. Insertof systemalso causes refrigerant flowing within evaporator coilto change direction, which improves the efficiency of the heat transfer of system.

Although this disclosure describes and depicts the components of systemarranged in a particular order, this disclosure recognizes that systemmay include (or exclude) one or more components and the components may be arranged in any suitable order. For example, insertof systemmay include more or less than four sides. As another example, insertmay be located within evaporator coilwithout support legs. As still another example, insertmay include support legsalong the length of core, such as at a midpoint of core. As yet another example, insertmay be twisted more or less than 90 degrees (e.g., 45 degrees or 180 degrees). As still another example, evaporator coilmay include one or more bends or elbows. Althoughillustrates a particular number of evaporator coils, inserts, cores, support legs, endsand, and sides, this disclosure contemplates any suitable number of evaporator coils, inserts, cores, support legs, endsand, and sides.

illustrates an example methodfor installing insertofinto evaporator coil. At stepof method, coreof insertis twisted 90 degrees. Coremay be twisted by rotating second end90 degrees respective to first end. Prior to twisting core, sideof corefaces one direction. After twisting core, sideof corefaces a first direction at first endand a second direction at second end, wherein refrigerant may flow from first end(upstream) to second end(downstream). In certain embodiments, coremay be twisted more or less than 90 degrees (e.g., 45 degrees or 180 degrees).

At stepof method, coreof insertis placed inside evaporator coil. Insertmay be entirely located within evaporator coil. Insertmay be the same length as evaporator coil. In the illustrated embodiment of, coreof insertis placed within evaporator coilsuch that an air gap exists between the outer surface of coreand the inner surface of evaporator coil. In some embodiments, coremay be placed within evaporator coilsuch that one or more sides, edges, or corners of corecontact the inner surface of evaporator coil. For example, coreof insertmay be sized such that each of the four edges along the length of corecontact the inner surface of evaporator coil.

At stepof method, support legsare added to core. In the illustrated embodiment of, a support legis added to each corner of coreat first endand second end. In some embodiments, support legsmay be added to one or more sides of core. Support legsmay be located at any suitable location along the length of core. Support legs may be attached to coreby any suitable method. For example, support legsmay brazed or glued to an outer surface of core. In certain embodiments, coreand support legsmay be manufactured as one component.

At step, support legsare brazed to the inner surface of evaporator coil. Brazing support legsto the inner surface of evaporator coilstabilizes insertwithin evaporator coil. In some embodiments, support legsmay be secured to the inner surface of evaporator coilusing a different method than brazing. For example, support legsmay be glued to the inner surface of evaporator coil. As another example, support legsmay include springs that press against the inner surface of evaporator coil.

Modifications, additions, or omissions may be made to methoddepicted in. Methodmay include more, fewer, or other steps. For example, stepdirected to brazing insertto evaporator coilmay be eliminated. Steps may also be performed in parallel or in any suitable order. For example, stepdirected to twisting coremay occur after stepdirected to placing corewithin evaporator coil. As another example, stepdirected o adding support legsto insertmay occur prior to stepdirected to placing corewithin evaporator coil. One or more steps of methodmay be performed by a machine (e.g., a robot) or by a human.

illustrate different types of insertsfor evaporator coil.shows a cross-sectional view of insertthat functions as a plug support, which may be suitable for shorter lengths of evaporator coilwhere no inside support is required. Insertofis a hatched configuration that includes coreand support legs. Corehas a square cross-sectional area (e.g., a square cross-sectional shape) with four equal sides. In the illustrated embodiment, coreis made of a solid material. In some embodiments, coremay be hollow. Insertofincludes two support legsat each of the four corners of core. The two support legsat each corner are located at a 90 degree angle from each other. Coreand support legsofmay be made of the same material. Coreand support legsofmay be manufactured as one integral component. Support legscontact an inner surface of evaporator coil. Friction and/or compression between support legsand the inner surface of evaporator coilstabilize insertwithin evaporator coilas refrigerant flows through evaporator coil. Insertofdoes not require brazing to secure insertwithin evaporator coil. Insertmay be twisted along a length of evaporator coil.

Insertofis a round cluster insertthat includes a central coreand four support legs. Corehas a cross-sectional area in the shape of a circle. The cross-sectional area of coreis smaller than the cross-sectional area of the opening of evaporator coilas measured from the inner surface of evaporator coil. Each support leghas a cross-sectional area in the shape of a circle. The cross-sectional area of each support legis smaller than the cross-sectional area of core. Coreand support legsofmay be made of the same material. Coreand support legsofmay be manufactured separately or as a single component. Corecontacts each support legalong a length of coreand support leg. Coreand support legsmay be attached (e.g., brazed or glued) to each other. An outer edge of each support legcontacts an inner surface of evaporator coilalong the length of evaporator coil. Friction and/or compression between support legsand the inner surface of evaporator coilstabilize insertwithin evaporator coilas refrigerant flows through evaporator coil. Insertofdoes not require brazing to secure insertwithin evaporator coil. One or more components of insertmay be twisted along a length of evaporator coil.

Insertofincludes corethat has a cross-sectional area in the shape of an oval. The cross-sectional area of coreis smaller than the cross-sectional area of the opening of evaporator coilas measured from the inner surface of evaporator coil. Two outer edges along the length of coreofcontact an inner surface of evaporator coil. Friction and/or compression between the outer edges of coreand the inner surface of evaporator coilstabilize insertwithin evaporator coilas refrigerant flows through evaporator coil. Insertofdoes not require brazing to secure insertwithin evaporator coil. Insertmay be twisted along a length of evaporator coil.

Insertofincludes a central coreand four support legs. Corehas a cross-sectional area in the shape of a square having four equal sides. The cross-sectional area of coreis smaller than the cross-sectional area of the opening of evaporator coilas measured from the inner surface of evaporator coil. Each support legofincludes an extensionand a wheel. Each extensionextends from a corner of coresuch that each extensionis at a 135 degree angle to the two sides of corethat form the respective corner. Coreand each extensionof each support legmay be made of the same material (e.g., copper). Coreand extensionsofmay be manufactured as one integral component.

Extensionofmay include a support for wheelof support leg. The support may be curved such that it takes the shape of a semi-circle, as illustrated. Each wheelof each support legmay have a cross-sectional area in the shape of a circle. Wheelis located within the support of extension. The support may act as a clamp to secure wheelto the support. As shown in options A and B of, wheelof support legmay be solid or hollow, respectively. Wheelmay be made of a flexible material (e.g., Teflon) such that the hollow shape of option B allows wheelto flex more than the solid shape of option A. Friction and/or compression between wheelsof support legsand the inner surface of evaporator coilstabilize insertwithin evaporator coilas refrigerant flows through evaporator coil. Insertofdoes not require brazing to secure insertwithin evaporator coil. Insertmay be twisted along a length of evaporator coil.

Insertofis a wire type insert that has a cross-sectional area in the shape of a circle. Insertofcurves within evaporator coilat 180 degree turns. The curves of insertcreate semi-circle shapes such that an outer edge of a peak of each semi-circle of insertcontacts the inner surface of evaporator coil. Insertmay be made of a soft material to simplify installation. For example, insertmay accommodate bends in evaporator coilswith little or no complications. Insertofdoes not require brazing to secure insertwithin evaporator coil.

Althoughdescribe and depict the components of insertsarranged in a particular order, this disclosure recognizes that insertsmay include (or exclude) one or more components and the components may be arranged in any suitable order. For example, insertofmay include support legsat the midpoint of each side of core. As another example, insertofmay include more or less than four support legs. As still another example, insertofmay have a cross-sectional area in the shape of a triangle or a quatrefoil. Althoughillustrates a particular number of evaporator coils, inserts, cores, and support legs, this disclosure contemplates any suitable number of evaporator coils, inserts, cores, and support legs.

illustrates example dimensions for insertof evaporator coil.is a cross-sectional view of insertand evaporator coil. Insertofhas a cross-sectional area in the shape of a circle. The diameter Dof the cross-sectional area at first endof insertis greater than the diameter Dof the cross-sectional area at second endof insert, wherein refrigerant may flow from first end(upstream) to second end(downstream). The reduction in diameter from first endto second endof evaporator coilmay improve the efficiency of the refrigerant system by reducing the pressure drop along evaporator coil. For example, first endof evaporator coil (e.g., refrigerant coil) systemmay be an inlet and second endof systemmay be an outlet. Refrigerant entering the inlet of evaporator coilat first endis primarily in liquid form (e.g., 90 percent liquid and 10 percent vapor). As the refrigerant flows within evaporator coil, it vaporizes such that the refrigerant is in vapor form at the second end. As the refrigerant changes to vapor, its volume increases, causing an increase in pressure. Decreasing diameter Dat second end(e.g., the outlet of evaporator coil) may allow the vapor to exit evaporator coilwith little or no complications.

illustrates example reductions in refrigerant charge based on the size of insertrelative to the size of evaporator coil. Tableofincludes the following columns: columnshowing the outside diameter of evaporator coil, columnshowing an inside cross-sectional area for evaporator coil, columnshowing a size of insertof evaporator coil, columnshowing a cross-sectional area of insertof evaporator coil, columnshowing a percentage volume drop of evaporator coilafter locating insertwithin evaporator coil, columnshowing notes regarding the different configurations of inserts, and columnshowing a shape of insert. Tableincludes rows A, B, and C. Columnof tablelists the outside diameter of evaporator coilas ⅜ inch (i.e., 0.375 inches) for rows A, B, and C. Columnof tablelists the inside area of evaporator coilas 0.0759 square inches for rows A, B, and C.

Row A shows the percentage volume drop of evaporator coilafter locating an insertwith a square shape, as shown in columnof row A, within evaporator coil. In some embodiments, the square insertof row A is coreof. As shown in columnsandof table, square insertof row A has a size of 0.1875 inches by 0.1875 inches and an area of 0.03515 square inches. After locating square insertwithin evaporator coil, the volume for refrigerant flow within evaporator coildecreases by approximately 46 percent, as indicated in columnof row A. As noted in columnof row A, the length and width of insertare each half the outside diameter of evaporator coil.

Row B shows the percentage volume drop of evaporator coilafter locating an insertwith a round cluster shape, as shown in columnof row B, within evaporator coil. In some embodiments, round cluster insertof row B is insertof, which includes round coreand four round support legs. As shown in columnof table, round coreof insertof row B has a diameter of 0.155 inches and each round support legof inserthas a diameter of 0.0778 inches. As shown in columnof, round cluster insertof row B has an area of 0.03784 square inches. After locating round cluster insertwithin evaporator coil, the volume for refrigerant flow within evaporator coildecreases by approximately 50 percent, as indicated in columnof row B. As noted in columnof row B, the diameter of coreand two support legsof insertare approximately half the outside diameter of evaporator coil.

Row C shows the percentage volume drop of evaporator coilafter locating an inserthaving an oval shape, as shown in columnof row C, within evaporator coil. In some embodiments, oval insertof row C is insertof. As shown in columnsandof table, oval insertof row C has a length “a” of 0.311 inches, a width “b” of 0.0.155 inches, and an area of 0.03796 square inches. After locating round cluster insertwithin evaporator coil, the volume for refrigerant flow within evaporator coildecreases by 50 percent, as indicated in columnof row C. As noted in columnof row C, length “a” is equal to twice the width “b” of oval insert.

In certain embodiments, the cross-sectional area of one or more shapes of insertsshown in columnof rows A, B, and C of tablemay be reduced. For example, the width and length of square insertof row A at an inlet of evaporator coilmay be twice the width and length, respectively, of square insertof row A at the outlet of evaporator coil. Reducing the size of insertin this manner may save approximately 70 percent of refrigerant charge.

Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context.

The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, feature, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Additionally, although this disclosure describes or illustrates particular embodiments as providing particular advantages, particular embodiments may provide none, some, or all of these advantages.