EXPANSION ASSEMBLY FOR HEAT EXCHANGER

Abstract

An expansion assembly for use with a heat exchanger includes a block thermal expansion valve; and a distributor directly connected to the block thermal expansion valve; wherein the distributor comprises a tube having a plurality of openings formed therein.

Description

BACKGROUND

Exemplary embodiments pertain to the field of expansion devices. More particularly, the present disclosure relates to an expansion assembly for use with a heat exchanger.

Heat exchangers, such as microchannel heat exchangers, are widely used for heat transfer in heating, ventilation and air conditioning (HVAC) applications. Traditional thermal expansion valves (TXVs) are not conducive to the microchannel distributor and header geometry, causing the TXVs to be under utilized in such applications.

BRIEF DESCRIPTION

In one embodiment, an expansion assembly for use with a heat exchanger includes a block thermal expansion valve; and a distributor directly connected to the block thermal expansion valve; wherein the distributor comprises a tube having a plurality of openings formed therein.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the distributor is configured for placement within a manifold of the heat exchanger.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein a housing of the block thermal expansion valve and the distributor are made from the same material.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the housing of the block thermal expansion valve and the distributor are made from aluminum.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the distributor is directly connected to the block thermal expansion valve by at least one of press fitting, brazing and adhesives.

In another embodiment, a heat exchanger includes an expansion assembly including a block thermal expansion valve and a distributor directly connected to the block thermal expansion valve; a first manifold, the distributor positioned within the first manifold; a second manifold configured to receive refrigerant from the first manifold; and a conduit fluidly connecting the second manifold to the block thermal expansion valve.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the distributor comprises a tube having a plurality of openings formed therein.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein a housing of the block thermal expansion valve and the distributor are made from the same material.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the housing of the block thermal expansion valve and the distributor are made from aluminum.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the distributor is directly connected to the block thermal expansion valve by at least one of press fitting, brazing and adhesives.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the block thermal expansion valve is directly mounted to first manifold.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the block thermal expansion valve is directly mounted to the first manifold by at least one of press fitting, brazing and adhesives.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein a housing of the block thermal expansion valve, the distributor and the first manifold are made from the same material.

In addition to one or more of the features described herein, or as an alternative, further embodiments may include wherein the housing of the block thermal expansion valve, the distributor and the first manifold are made from aluminum.

Technical effects of embodiments of the present disclosure include providing a block thermal expansion valve and an integrated distributor for use with a heat exchanger, such as a microchannel heat exchanger.

The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 depicts a vapor compression cycle in an example embodiment;

FIG. 2 depicts a heat absorption heat exchanger in an example embodiment;

FIG. 3 depicts a cross-sectional view of the heat absorption heat exchanger in an example embodiment;

FIG. 4 depicts the heat absorption heat exchanger in a housing in an example embodiment;

FIG. 5 depicts an expansion assembly in an example embodiment;

FIG. 6 depicts a block thermal expansion valve in an example embodiment; and

FIG. 7 depicts the expansion assembly mounted to the heat absorption heat exchanger in an example embodiment.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Referring now to FIG. 1, a vapor compression refrigeration cycle 20 of a heating, ventilation and air conditioning (HVAC) system is schematically illustrated. Exemplary HVAC systems include, but are not limited to, residential, split, packaged, chiller and rooftop, for example. Other embodiments of this disclosure may be applied to refrigeration application. A refrigerant is configured to circulate through the vapor compression cycle 20 such that the refrigerant absorbs heat when evaporated at a low temperature and pressure and releases heat when condensed at a higher temperature and pressure.

Within this vapor compression refrigeration cycle 20, the refrigerant flows in a clockwise direction as indicated by the arrows. The compressor 22 receives refrigerant vapor from the heat absorption heat exchanger (e.g., an evaporator) 24 and compresses it to a higher temperature and pressure, with the relatively hot vapor then passing to the heat rejection heat exchanger (e.g., a condenser or gas cooler) 26 where it is cooled by a heat exchange relationship with a cooling medium (not shown) such as air. The refrigerant then passes from the heat rejection heat exchanger 26 to an expansion device 28, wherein the refrigerant is expanded to a low temperature state as it passes to the heat absorption heat exchanger 24. The relatively cold two-phase refrigerant mixture then passing to the heat absorption heat exchanger 24 where it is boiled to a vapor state by a heat exchange relationship with a heating medium (not shown) such as air. The low pressure refrigerant vapor then returns to the compressor 22 where the cycle is repeated.

Referring now to FIG. 2, an example of a heat absorption heat exchanger 24 is illustrated in more detail. The heat absorption heat exchanger 24 includes at least a first manifold or header 32, a second manifold or header 34 spaced apart from the first manifold 32, and a plurality of heat exchange tube segments 36 extending in a spaced, parallel relationship between and connecting the first manifold 32 and the second manifold 34. In the illustrated, non-limiting embodiments, the first manifold 32 and the second manifold 34 are oriented generally along a first direction and the heat exchange tube segments 36 extend generally along a second direction between the two manifolds 32, 34.

Referring now to FIG. 3, a cross-sectional view of an embodiment of a heat exchange tube segment 36 is illustrated. The heat exchange tube segment 36 includes a flattened microchannel heat exchange tube having a leading edge 40, a trailing edge 42, a first surface 44 and a second surface 46. The leading edge 40 of the heat exchange tube segment 36 is upstream of its respective trailing edge 42 with respect to airflow, A, passing through the heat exchanger 24 and flowing across the heat exchange tube segment 36. An interior flow passage of the heat exchange tube segment 36 may be divided by interior walls into a plurality of discrete flow channels 48 that extend over a length of the heat exchange tube segment 36 from an inlet end to an outlet end and establish fluid communication between the first and second manifolds 32, 34. The flow channels 48 may have a circular cross-section or, for example, a rectangular cross-section, a trapezoidal cross-section, a triangular cross-section or another non-circular cross-section. The heat exchange tube segment 36 including discrete flow channels 48 may be formed using known techniques and materials, including but not limited to, extruding or folding.

Fins 50 are positioned between the heat exchange tube segments 36. In some embodiments, the fins 50 are formed from a continuous strip of fin material folded in a ribbon-like serpentine fashion thereby providing a plurality of closely spaced fins 50 that extend generally orthogonally to the heat exchange tube segments 36. Thermal energy exchange between one or more fluids within the heat exchange tube segments 36 and an air flow, A, occurs through the outside surfaces 44, 46 of the heat exchange tube segments 36 collectively forming a primary heat exchange surface, and also through thermal energy exchange with the fins 50, which defines a secondary heat exchange surface.

FIG. 4 depicts an exemplary heat absorption heat exchanger 24 positioned in a housing 62. The housing 62 may be part of an internal air handler of a residential HVAC system. As illustrated in FIG. 4, a bend 60 is formed in each heat exchange tube segment 36 of the heat absorption heat exchanger 24, resulting in a V-shape of the heat absorption heat exchanger 24. In some embodiments the bend 60 has an included bend angle 70 less than 90 degrees. In other embodiments the included bend angle 70 is between 15 and 45 degrees. The heat absorption heat exchanger 24 may be placed in a housing 62, with the bend 60 oriented such that the bend is closest to the incoming airflow, A. A first leg 64 of the heat absorption heat exchanger 24 extends from the bend 60 toward the first manifold 32 and a second leg 66 of the evaporator extends from the bend 60 toward the second manifold 34. In some embodiments, the heat absorption heat exchanger 24 is situated in the housing 62 such that the bend 60 is located vertically lower than the first manifold 32 and the second manifold 34. The heat absorption heat exchanger 24 may be secured in the housing 62 via the first manifold 32 and the second manifold 34.

A drain pan 72 is located vertically below the bend 60 to capture condensation from the heat exchange tube segments 36 and fins 50. The V arrangement of the heat absorption heat exchanger 24 encourages the condensation to run down the first leg 64 and the second leg 66 toward the bend 60, where the condensation falls from the bend 60. Embodiments are not limited to a V arrangement of the heat absorption heat exchanger 24. The heat absorption heat exchanger 24 may be configured in an “A” arrangement, as or one or more slabs, or other configurations.

FIG. 5 depicts an expansion assembly 100 in an example embodiment that may be used with the heat absorption heat exchanger 24. The expansion assembly 100 includes a block thermal expansion valve (TXV) 110 and a distributor 140 connected directly to the block TXV 110. A first port 1 of the block TXV 110 receives refrigerant from the heat rejection heat exchanger 26. Reduced pressure refrigerant is directed from port 2 to the distributor 140. From the distributor 140, refrigerant flows into the first manifold 32. Refrigerant from the second manifold 34 is provided to port 3, then to port 4 and then to the suction inlet of compressor 22.

The distributor 140 may be formed of a tube 142 having a plurality of openings 144 formed therein. Refrigerant from port 2 of the block TXV 110 flows along the interior of tube 142 and is emitted though the openings 144 into the first manifold 32. The distributor 140 may be directly secured to a housing of the block TXV 110 using a variety of techniques, such as press fitting, brazing, adhesives, etc. In an example embodiment, the housing of the block TXV 110 and the distributor 140 are made from a common material, e.g., aluminum.

FIG. 6 depicts a block TXV 110 in an example embodiment. Operation of the block TXV 110 occurs through refrigerant expansion/contraction within a diaphragm 11. As refrigerant from the second manifold 34 passes over a sensing element 12, expansion or contraction of the refrigerant takes place causing an activating pin 8 to move a ball valve 6 away from or closer to a metering orifice 5. This allows more or less refrigerant to enter the first manifold 32. Various pressures within the block TXV 110 provide for metering refrigerant to the first manifold 32 through port 2. A first pressure, F1, is provided by a sealed diaphragm 11 in response to a temperature of refrigerant leaving the second manifold 34 at port 3. As refrigerant leaving the second manifold 34 passes over a sensing element 12 increases in temperature, the refrigerant 9 above the diaphragm 11 expands moving pin 8 downwards pushing ball valve 6 away from the metering orifice 5. A second pressure, F2, is provided by a passage 10 in the block TXV 110 where refrigerant can build up under the diaphragm 11 to act as an opposing pressure against F1 to regulate an amount of refrigerant admitted into the first manifold 32. A third pressure, F3, is provided by a spring 7 located under the ball valve 6 and acts as an opposing force to move the ball valve 6 towards the metering orifice 5 and to reduce refrigerant flow to the first manifold 32.

FIG. 7 depicts the expansion assembly 100 mounted to the first manifold 32 of the heat absorption heat exchanger 24 in an example embodiment. Although not visible in FIG. 7, the distributor 140 extends into the interior of the first manifold 32. A conduit 150 provides fluid path from the second manifold 34 to port 3 of the block TXV 110. The block TXV 110 may be mounted directly to the first manifold 32 using a variety of techniques, such as press fitting, brazing, adhesives, etc. In an example embodiment, a housing of the block TXV 110 and the first manifold 32 are made from a common material, e.g., aluminum. The first manifold 32 provides a sturdy mounting location for the expansion assembly 100.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.

Claims

1. An expansion assembly for use with a heat exchanger, the expansion assembly comprising: a block thermal expansion valve; anda distributor directly connected to the block thermal expansion valve;wherein the distributor comprises a tube having a plurality of openings formed therein.

2. The expansion assembly of claim 1, wherein the distributor is configured for placement within a manifold of the heat exchanger.

3. The expansion assembly of claim 1, wherein a housing of the block thermal expansion valve and the distributor are made from the same material.

4. The expansion assembly of claim 3, wherein the housing of the block thermal expansion valve and the distributor are made from aluminum.

5. The expansion assembly of claim 1, wherein the distributor is directly connected to the block thermal expansion valve by at least one of press fitting, brazing and adhesives.

6. A heat exchanger comprising: an expansion assembly including a block thermal expansion valve and a distributor directly connected to the block thermal expansion valve;a first manifold, the distributor positioned within the first manifold;a second manifold configured to receive refrigerant from the first manifold; anda conduit fluidly connecting the second manifold to the block thermal expansion valve.

7. The heat exchanger of claim 6, wherein the distributor comprises a tube having a plurality of openings formed therein.

8. The heat exchanger of claim 6, wherein a housing of the block thermal expansion valve and the distributor are made from the same material.

9. The heat exchanger of claim 8, wherein the housing of the block thermal expansion valve and the distributor are made from aluminum.

10. The heat exchanger of claim 6, wherein the distributor is directly connected to the block thermal expansion valve by at least one of press fitting, brazing and adhesives.

11. The heat exchanger of claim 6, wherein the block thermal expansion valve is directly mounted to first manifold.

12. The heat exchanger of claim 11, wherein the block thermal expansion valve is directly mounted to the first manifold by at least one of press fitting, brazing and adhesives.

13. The heat exchanger of claim 6, wherein a housing of the block thermal expansion valve, the distributor and the first manifold are made from the same material.

14. The heat exchanger of claim 13, wherein the housing of the block thermal expansion valve, the distributor and the first manifold are made from aluminum.