Patent Description:
Power electronic devices such as motor drives can generate waste heat during operation based on the efficiency of the device. Additionally, when the power electronic devices heat up, their efficiency can degrade adding to the amount of heat they generate. When configured into a refrigeration system, effective thermal integration of these devices can be important aspect to the system's overall efficiency and reliability. Consequently, a goal of the system integrator is to maintain these components within a range of operating temperatures which will maximize the system efficiency. Accordingly, there remains a need in the art for heat exchangers configured to closely integrate with power electronic devices which can maintain optimal temperatures for these components under a variety of load conditions.

<CIT> and <CIT> each disclose electronic devices provided in combination with heat dissipation devices. The electronic devices are mounted to a base structure, this base structure being mounted to the heat dissipation device by grease. A sealing or retaining member can be provided to prevent outflow of the grease. Further prior art is disclosed in <CIT>.

Viewed from a first aspect, there is provided a heat exchanger assembly as claimed in claim <NUM>.

The gasket may extend about at least a portion of a periphery of the heat sink interface.

The gasket may extend about an entire periphery of the heat sink interface.

The gasket may be compressed to form a seal between the heat sink interface and the surface of the housing of the heat exchanger.

The surface of the heat exchanger may have a substantially planar configuration and the gasket is positioned in overlapping arrangement with the surface.

Only a portion of the gasket may extend beyond the surface of the heat exchanger.

The gasket may have a substantially continuous tube-like configuration.

The gasket may have a substantially planar configuration.

The thermal interface material may be thermal grease.

The heat exchanger may comprise: the housing, wherein said housing has an inlet and an outlet formed therein; a fluid circuit arranged within the housing and extending between the inlet and the outlet; and a fluid circulating through the fluid circuit.

The fluid circuit may comprise: an inlet manifold; an outlet manifold; and a plurality of fluid passages connecting the inlet manifold and the outlet manifold.

At least one of the inlet manifold, the outlet manifold, and the plurality of fluid passages may be formed as a recess formed in the housing.

The inlet may be disposed below the outlet such that during operation a flow direction of a refrigerant through the inlet manifold and the outlet manifold opposes gravity.

The housing may comprise a first housing portion and a second housing portion joined along corresponding mating surfaces.

The first housing portion and the second housing portion may be a plate.

With reference now to <FIG>, a schematic illustration of an example of a heat exchanger <NUM> is illustrated according to an embodiment. As shown, the heat exchanger <NUM> includes a housing <NUM> formed from a heat conductive material, such as a metal material. For example, the housing <NUM> may be formed from any suitable metal, e.g., aluminum, aluminum alloy, steel, steel alloy, copper, copper alloy, or the like. In the illustrated, non-limiting embodiment, the housing <NUM> is formed from a plurality of housing portions, such as a first housing portion <NUM>, and a second housing portion <NUM>, joined along corresponding mating surfaces to form a seam <NUM> therebetween. In such embodiments, the first and second housing portions <NUM>, <NUM> can abut one another along a side and can be joined using any suitable means such as brazing, welding, clamping, compressing, bolting, and the like. Although two housing portions <NUM>, <NUM> are illustrated in the exemplary embodiments, it should be understood that a housing <NUM> formed from any number of housing portions including a single housing portion, or more than two housing portions for example, are contemplated.

The mating surfaces of the first and second housing portions <NUM>, <NUM> may be configured to correspond to one another, e.g., to fit together to seal a fluid circuit therebetween (the fluid circuit to be described in more detail below). In an embodiment, the mating surfaces of the first and second housing portions <NUM>, <NUM> include precision surfaces formed from a process having highly accurate and precise dimensional control, such as through computer numerical control (CNC) machining process and/or net shape, or near net shape manufacturing process. Optionally a sealing material can be disposed between the first and second housing portions <NUM>, <NUM> to aide in preventing leakage from the fluid circuit.

As shown in <FIG>, the first and second housing portions <NUM>, <NUM> can have different thicknesses, measured along the z-axis. In the illustrated, non-limiting embodiment, a thickness of the first housing portion <NUM> is greater than a thickness of the second housing portion. However, embodiments where the first housing portion <NUM> and the second housing portion <NUM> are equal in thickness, or alternatively, where a thickness of the second housing portion <NUM> is greater than a thickness of the first housing portion <NUM> are also contemplated. In an embodiment, each of the first housing portion <NUM> and the second housing portion <NUM> is formed as a substantially solid plate. However, embodiments where one or more of the housing portions <NUM>, <NUM> has another configuration are also contemplated herein.

The heat exchanger <NUM> includes a fluid circuit formed between the first and second housing portions <NUM>, <NUM>. The fluid circuit includes a fluid inlet <NUM> and fluid outlet <NUM> formed in the housing <NUM>. The fluid inlet <NUM> and the fluid outlet <NUM> can be any shape, such as in the depth dimension (e.g., in the z-x plane of the attached figure), including the shape of a circle, oval, triangular, square, rectangular, or any simple polygonal shape or portion thereof. Further, the perimeter of one or both of the fluid inlet <NUM> and the fluid outlet <NUM> can be formed by a recess in at least one or both of the housing portions <NUM>, <NUM>. The recess may extend to an edge of a respective housing portion, may be arranged centrally relative to a housing portion, or may overlap with the seam <NUM> defined between two adjacent housing portions <NUM>, <NUM>.

An example of the fluid circuit is best illustrated in the cross-sectional view of the heat exchanger <NUM> shown in <FIG>. In addition to the inlet <NUM> and the outlet <NUM>, the fluid circuit may include a first or inlet manifold <NUM>, a second or outlet manifold <NUM>, and a plurality of fluid passages <NUM> connecting the first and second manifolds <NUM>, <NUM>. The fluid inlet <NUM> can be configured to connect a first heat transfer fluid (e.g., refrigerant) source, such as a condenser of a vapor compression system for example, to the inlet manifold using any suitable mechanical connection. Similarly, the fluid outlet <NUM> can be configured to connect a first heat transfer fluid sink, such as an evaporator of a vapor compression system for example, to the outlet manifold using any suitable mechanical connection (e.g., compression coupling, brazing, welding, and the like). In an embodiment, the fluid inlet <NUM> is disposed vertically below the fluid outlet <NUM> such that during operation of the heat exchanger <NUM>, a flow direction of a refrigerant through the inlet and outlet manifolds <NUM>, <NUM> opposes gravity.

One or more of the inlet manifold <NUM>, the outlet manifold <NUM>, and the plurality of fluid passages <NUM> is formed as a recess in at least one of the first housing portion <NUM> and the second housing portion <NUM>. In an embodiment, the inlet manifold <NUM>, the outlet manifold <NUM>, and the plurality of fluid passages <NUM> are formed as a plurality of connected recesses in at least one housing portion, such as the second housing portion <NUM> for example. Accordingly, the plurality of recesses form the fluid circuit disposed between the first and second housing portions <NUM>, <NUM> when the housing portions <NUM>, <NUM> are joined. For example, a first housing portion <NUM> having a plurality of connected recesses can be joined to a flat, second housing portion <NUM> that does not have any recesses formed therein. In another embodiment, a first housing portion <NUM> and a second housing portion <NUM> can each have a plurality of connected recesses which mirror one another such that when the first and second housing portions <NUM>, <NUM> are joined, the connected recesses form the fluid circuit. The plurality of connected recesses can have any shape in the depth dimension (e.g., as projected onto a z-y plane of the attached figures, into the plate), including semi-circular, semi-oval, triangular, square, rectangular, or any simple polygonal shape or portion thereof.

The mating surfaces of the first and second housing portions <NUM>, <NUM> can substantially border the plurality of connected recesses. Optionally, the mating surfaces can include raised or recessed portions, or other engagement features to aid in alignment of the housing portions <NUM>, <NUM> prior to joining.

A heat exchanger <NUM> as described herein can be used, such as in a vapor compression system for example, to cool one or more power electronic modules <NUM>. As described herein, a heat exchanger <NUM> having one or more power electronics modules <NUM> mounted thereon may be considered a heat exchanger assembly. The term "power electronic module" as used herein can refer to any electronic component which can provide a controlled output power by modulating and/or converting a supplied input power (e.g., a variable frequency drive, power rectifier, power converter, and the like). Such a power electronic module <NUM> can be used to control the speed of a compressor and/or the speed of the fan of a vapor compression system (e.g., chiller) based on various predetermined system conditions. With reference again to <FIG>, and further reference to <FIG>, one or more power electronic modules <NUM> are mounted directly to a surface <NUM> of at least one of the plurality of housing portions, such as first housing portion <NUM> for example. According to the invention, the plurality of power electronics modules <NUM> are mounted to a vertically oriented surface of the housing <NUM>. However, embodiments not covered by the present invention, where one or more power electronics modules <NUM> are mounted to a surface of a housing <NUM> having a non-vertical orientation, such as a horizontal surface for example, are also contemplated. The power electronic modules <NUM> may be mounted to the housing <NUM> of the heat exchanger <NUM> via one or more fasteners in such a way that facilitates the transfer of thermal energy away from the power electronics module <NUM>.

The one or more power electronics modules <NUM> may include a printed circuit board <NUM> on which various other electrical components (not shown) are mounted (e.g., protection, signal processing, and filtering related components). The reliability and life of the one or more power electronics modules <NUM> can depend upon precluding such electrical components from operating at high temperatures and/or precluding their exposure to thermal shock. Because electrical components inside the power electronics modules <NUM> can generate a large amount of heat, each of the power electronics modules <NUM> has a heat sink interface <NUM> (see <FIG>) which is designed for attachment to a heat sink, such as the heat exchanger <NUM>. When the power electronics modules <NUM> are secured in thermal communication with the heat exchanger <NUM>, the heat generated by the power electronics module <NUM> is at least partially removed through the heat sink interface <NUM> to keep the one or more power electronics module <NUM> cooled below its maximum allowable operating temperature (e.g., <NUM>).

A thermal interface material, illustrated schematically at <NUM>, may be positioned between the heat sink interface <NUM> of a respective power electronics module <NUM> and the adjacent surface <NUM> of the housing <NUM> configured to receive the power electronics module <NUM>. In an embodiment, the thermal interface material <NUM> is a thermal grease or compound having a high thermal conductivity. However, in other embodiments the thermal interface material may include a multiphase material and/or an elastomeric material such as a thermal pad. In applications where a power electronics module <NUM> is mounted in a vertical plane relative to a surface <NUM> of the housing <NUM> of the heat exchanger <NUM>, the gravitational forces acting on the thermal grease <NUM> may cause the thermal grease <NUM> to move or drip relative to the heat sink interface <NUM>. In addition, if condensation collects on the surface <NUM> of the heat exchanger <NUM>, such as resulting from the heat removal therefrom, the condensation in combination with the gravitational forces may wash the thermal grease <NUM> away from the heat sink interface <NUM>.

In an embodiment, to prevent this loss or washing away of the thermal interface material <NUM> at the heat sink interface <NUM>, a gasket <NUM> is disposed between a portion of the power electronics module <NUM> and the heat exchanger <NUM>. The gasket <NUM> may extend about at least a portion of the perimeter of the power electronics module <NUM> at the heat sink interface <NUM>. In the illustrated, non-limiting embodiment, the gasket <NUM> extends about an entire periphery of the heat sink interface <NUM>. In such embodiments, the dimensions of the gasket <NUM> are substantially complementary to, or slightly smaller than, the length and width of a respective power electronics module <NUM>. The gasket <NUM> may have a substantially continuous tube-like configuration, or alternatively, may have a substantially planar configuration similar to a washer. However, any suitable configuration of a gasket <NUM> is contemplated.

In an example not in accordance with the present invention, the surface <NUM> of the heat exchanger <NUM> configured to receive the power electronics module <NUM> is generally planar (see <FIG>). As a result, the entirety of the gasket <NUM> is positioned adjacent to and in overlapping arrangement with the surface <NUM>. In an embodiment in accordance with the present invention, best shown in <FIG>, a gasket groove or recess <NUM> complementary to the gasket <NUM> is formed in the surface <NUM> of the heat exchanger <NUM>. The gasket <NUM> is receivable within the gasket groove <NUM>, and therefore in such embodiments only a portion of the gasket <NUM> may protrude beyond the surface <NUM> towards the power electronics module <NUM>.

When the power electronics module <NUM> is installed about the surface <NUM> of the heat exchanger <NUM>, the gasket <NUM> may be at least partially compressed, thereby forming a seal between the surface <NUM> of the heat exchanger <NUM> and a surface of the power electronics module <NUM> at the heat sink interface <NUM>. Because the gasket <NUM> extends about at least a portion of the periphery of the heat sink interface <NUM>, the gasket forms a boundary or outer edge to at least a portion of the thermal interface material <NUM>. Accordingly, the seal formed between the power electronics module <NUM> and the surface <NUM> of the heat exchanger <NUM> by the compressed gaskets <NUM> forms a boundary that restricts movement of the thermal interface material <NUM> from adjacent to the heat sink interface <NUM>.

By using a gasket to retain the thermal interface material <NUM> between the heat sink interface <NUM> of a power electronics module <NUM> and a heat exchanger <NUM>, the thermal conductivity between the power electronics module <NUM> and the heat exchanger <NUM> is improved, thereby extending the life of the electronic components within the power electronics modules <NUM>.

Claim 1:
A heat exchanger assembly comprising:
a heat exchanger (<NUM>) including a housing (<NUM>);
a power electronics module (<NUM>) mounted to a surface (<NUM>) of the housing (<NUM>) of the heat exchanger (<NUM>), wherein the power electronics module (<NUM>) is thermally coupled to the heat exchanger (<NUM>) at a heat sink interface (<NUM>);
a thermal interface material (<NUM>) arranged between the heat sink interface (<NUM>) and the surface (<NUM>) of the housing (<NUM>) of the heat exchanger (<NUM>); and
a gasket (<NUM>) arranged between the heat sink interface (<NUM>) and the surface (<NUM>) of the housing (<NUM>) of the heat exchanger (<NUM>);
wherein the power electronics module (<NUM>) is mounted to a vertically oriented surface (<NUM>) of the housing (<NUM>);
wherein the gasket (<NUM>) surrounds at least a portion of the thermal interface material (<NUM>); and
wherein the gasket (<NUM>) defines a boundary that restricts movement of the thermal interface material (<NUM>) relative to the heat sink interface (<NUM>) and the surface (<NUM>) of the housing (<NUM>) of the heat exchanger (<NUM>);
characterized in that:
the surface (<NUM>) of the heat exchanger (<NUM>) has a gasket groove (<NUM>) formed therein, the gasket (<NUM>) being arranged within the gasket groove (<NUM>).