Patent Description:
A microchannel heat exchanger typically includes an inlet header, an outlet header, and a plurality of flat tubes connecting to and communicating with the headers. Each of the flat tubes has microchannels or small pathways for refrigerant (gas or liquid) to pass through. During operation, in a microchannel heat exchanger, refrigerant enters the inlet header via an inlet of the inlet header, then the refrigerant enters the flat tubes having microchannels, and the refrigerant conducts heat exchange with a fluid external to the flat tubes (e.g., air) to provide cooling or heating when the refrigerant flows within the flat tubes. After heat exchanging with the external fluid, the refrigerant leaves the flat tubes, enters the outlet header, and leaves the outlet header via an outlet of the outlet header.

<CIT> describes a unit cooler adapted for use in a refrigerated environment. The unit cooler includes a housing adapted to be positioned within the refrigerated environment and at least one microchannel evaporator coil supported by the housing. The at least one microchannel evaporator coil includes an inlet manifold and an outlet manifold. The inlet manifold has an inlet port for receiving refrigerant, and the outlet manifold has an outlet port for discharging the refrigerant.

<CIT> describes a modular microchannel heat exchanger that can be used with a BUS HVAC system. The BUS HVAC system can be configured to include a plurality of the microchannel heat exchanger module to meet, for example, a capacity requirement. The microchannel heat exchanger module may also include features that may help evenly distribute refrigerant in the microchannel heat exchanger module. A splitter with apertures may be included to help distribute the refrigerant in a longitudinal direction. One or more vertical structures may be included to slow down a velocity of the refrigerant.

<CIT> describes a condenser assembly adapted to condense an evaporated refrigerant for use in a retail store refrigeration system. The condenser assembly includes at least one microchannel condenser coil including an inlet manifold and an outlet manifold. The inlet manifold includes an inlet port for receiving the refrigerant, and the outlet manifold includes an outlet port for discharging the refrigerant. The condenser assembly also includes a frame supporting the at least one microchannel condenser coil.

This disclosure relates generally to microchannel heat exchangers. More specifically, the disclosure relates to systems and methods using common side connections for an oversized multi-slab microchannel heat exchanger.

In an embodiment, a multi-slab microchannel heat exchanger is disclosed. The heat exchanger includes a first slab having a first inlet header and a first outlet header, a second slab including a second inlet header and a second outlet header, a first inlet connector fluidly connected to the first inlet header, a first outlet connector fluidly connected to the first outlet header, a second inlet connector fluidly connected to the second inlet header, and a second outlet connector fluidly connected to the second outlet header. The first slab and the second slab are arranged successively in a direction along a length of the heat exchanger. The first inlet connector, the first outlet connector, the second inlet connector, and the second outlet connector are disposed at a same end of the heat exchanger. The first slab includes a first plurality of tubes. The first plurality of tubes is arranged successively in the direction along the length of the heat exchanger. Each of the first plurality of tubes includes microchannels. The first plurality of tubes includes inlets and outlets. The inlets of the first plurality of tubes are in fluid communication with the outlets of the first plurality of tubes through the microchannels of the plurality of tubes. The first inlet header is in fluid communication with the inlets of the first plurality of tubes. The first outlet header is in fluid communication with the outlets of the first plurality of tubes.

In an embodiment, the second slab has the same structure as (or similar structure to) the first slab. In an embodiment, the first slab and the second slab are a mirror image of each other.

In an embodiment, the first inlet connector, the first outlet connector, the second inlet connector, and the second outlet connector are disposed at a bottom of the heat exchanger.

In an embodiment, the first slab and the second slab converge at a point in the direction along the length of the heat exchanger. The second inlet connector and the second outlet connector extend from the point to the same end of the heat exchanger in the direction along the length of the heat exchanger.

In an embodiment, the second inlet connector is disposed inside the second outlet connector. The second inlet connector and the second outlet connector extend concentrically from the point to the same end of the heat exchanger in the direction along the length of the heat exchanger.

In an embodiment, the second outlet connector is disposed inside the second inlet connector. The second inlet connector and the second outlet connector extend concentrically from the point to the same end of the heat exchanger in the direction along the length of the heat exchanger.

In an embodiment, the second inlet connector is disposed inside the first inlet header. The second inlet connector and the first inlet header extend concentrically from the point to the same end of the heat exchanger in the direction along the length of the heat exchanger.

In an embodiment, the second outlet connector is disposed inside the first outlet header. The second inlet connector and the first outlet header connector extend concentrically from the point to the same end of the heat exchanger in the direction along the length of the heat exchanger.

In an embodiment, the first inlet connector and the first outlet connector are made of aluminum. In an embodiment, the second inlet connector and the second outlet connector are made of aluminum.

In an embodiment, the multi-slab microchannel heat exchanger further includes a third slab, a third inlet connector, and a third outlet connector. The first slab, the second slab, and the third slab are arranged successively in the direction along the length of the heat exchanger.

In an embodiment, the first inlet connector, the first outlet connector, the second inlet connector, the second outlet connector, the third inlet connector, and the third outlet connector are disposed at the same end of the heat exchanger.

It will be appreciated that the above embodiments are merely illustrative of the technical concept and features of the multi-slab microchannel heat exchanger, and these embodiments are to make a person skilled in the art understand the contents of the multi-slab microchannel heat exchanger and to implement the multi-slab microchannel heat exchanger without limiting the scope of protection of the multi-slab microchannel heat exchanger. Any features described in one embodiment can be combined with or incorporated/used into the other embodiment, and vice versa. The equivalent change or modification according to the substance of the multi-slab microchannel heat exchanger should be covered by the scope of protection of the multi-slab microchannel heat exchanger.

References are made to the accompanying drawings that form a part of this disclosure and which illustrate embodiments in which the systems and methods described in this specification can be practiced.

Some embodiments of the present application are described in detail with reference to the accompanying drawings so that the advantages and features of the present application can be more readily understood by those skilled in the art. The terms "near", "far", "top", "bottom", "left", "right" and the like described in the present application are defined according to the typical observation angle of a person skilled in the art and for the convenience of the description. These terms are not limited to specific directions. For example, for <FIG>, a "near" side can correspond to the left side of the paper, and a "far" side can correspond to the right side of the paper.

In an embodiment, a microchannel heat exchanger includes an inlet header and an outlet header, flat microchannel multiport tubes, and fins. These components are typically brazed together with non-corrosive fluxes. These components are typically made of aluminum or aluminum alloys, distinct in their composition and clads. During operation, in the microchannel heat exchanger, refrigerant enters the inlet header via an inlet of the inlet header, then the refrigerant enters the flat tubes having microchannels, and the refrigerant conducts heat exchange with a fluid external to the flat tubes (e.g., air) to provide cooling or heating when the refrigerant flows within the flat tubes. After heat exchanging with the external fluid, the refrigerant leaves the flat tubes, enters the outlet header, and leaves the outlet header via an outlet of the outlet header.

Due to the constraints of the manufacturing process(s) and/or production means, there might be limitations on the length of a single slab (also referred to as coils, coil slab, etc.) of a microchannel heat exchanger, especially a two-pass or multi-pass heat exchanger. In an example, the maximum length a single slab of a microchannel heat exchanger can be at or about <NUM> meters due to the manufacturing and/or production constraints, which is still relatively long compared with other refrigerant systems. In some applications, even a single slab with the maximum length is not long enough to meet the user's requirements (e.g., capacity requirements). In an embodiment, two or more slabs (of the same/similar length to optimize the refrigerant/fluid distribution) are used in a heat exchanger. In such embodiment, each slab can have a length of at or about one meter, or at or about the maximum length (e.g., <NUM> meters), or any suitable length. In an embodiment, an oversized microchannel heat exchanger is needed in a refrigeration circuit to meet the user's requirements (e.g., capacity requirements), by e.g., deploying multi-slab to achieve needed face area. In an embodiment, the scale of the refrigeration circuit capacity can be, for example, under <NUM> tons (e.g., at or about <NUM> tons in a part load mode). In an embodiment, the scale of the refrigeration circuit capacity (e.g., nominal capacity) can be, for example, at or over <NUM> tons. In another embodiment, the scale of the refrigeration circuit capacity (e.g., nominal capacity) can be, for example, at or over <NUM> tons. In yet another embodiment, the scale of the refrigeration circuit capacity (e.g., nominal capacity) can be, for example, from at or about <NUM> tons to at or about <NUM> tons.

In an embodiment, a multi-slab microchannel heat exchanger can be used in a refrigeration circuit such as, for example, in a heating, ventilation, air conditioning, and refrigeration (HVACR) system. In an embodiment, an HVACR system can be a rooftop unit or a heat pump air-conditioning unit in a unitary system (which combines heating, cooling, and/or fan sections in one or a few assemblies for simplified application and installation). In an embodiment, the multi-slab microchannel heat exchanger can be can be an evaporator. In an embodiment, the multi-slab microchannel heat exchanger can be a condenser.

In an embodiment, a slab of a multi-slab microchannel heat exchanger includes a plurality of flat tubes arranged successively in a direction along a length of the multi-slab microchannel heat exchanger. Each of the plurality of flat tubes has microchannels or small pathways for refrigerant (e.g., gas and/or liquid) to pass through. The microchannels have inlets and outlets. The multi-slab microchannel heat exchanger includes an inlet header that is in communication with the inlet of each of the plurality of flat tubes. The multi-slab microchannel heat exchanger further includes an outlet header that is in communication with the outlet of each of the plurality of flat tubes. In an embodiment, the inlet header and/or the outlet header fixedly connect to the plurality of flat tubes of the multi-slab microchannel heat exchanger.

Embodiments disclosed herein are directed to distribution/routing of heat transfer fluid (e.g., refrigerant or the like) flow to a multi-slab microchannel heat exchanger, preferably all from a local point (also referred to as a near side, the side of the heat exchanger where maintenance or service process can be readily performed) of connection. In an embodiment, the multi-slab microchannel heat exchanger is a single or independent component in a refrigeration circuit.

<FIG> is a schematic diagram of a refrigeration circuit <NUM>, according to an embodiment. The refrigeration circuit <NUM> generally includes a compressor <NUM>, a condenser <NUM>, an expansion device <NUM>, and an evaporator <NUM>. In an embodiment, the evaporator <NUM> can be a multi-slab microchannel heat exchanger. In another embodiment, the condenser <NUM> can be a multi-slab microchannel heat exchanger. The refrigeration circuit <NUM> is an example and can be modified to include additional components. For example, in an embodiment, the refrigeration circuit <NUM> can include other components such as, but not limited to, an economizer heat exchanger, one or more flow control devices, a receiver tank, a dryer, a suction-liquid heat exchanger, or the like.

The refrigeration circuit <NUM> can generally be applied in a variety of systems used to control an environmental condition (e.g., temperature, humidity, air quality, or the like) in a space (generally referred to as a conditioned space). Examples of such systems include, but are not limited to, HVACR systems, transport refrigeration systems, or the like. In an embodiment, an HVACR system can be a rooftop unit or a heat pump air-conditioning unit.

The compressor <NUM>, condenser <NUM>, expansion device <NUM>, and evaporator <NUM> are fluidly connected. In an embodiment, the refrigeration circuit <NUM> can be configured to be a cooling system (e.g., an air conditioning system) capable of operating in a cooling mode. In an embodiment, the refrigeration circuit <NUM> can be configured to be a heat pump system that can operate in both a cooling mode and a heating/defrost mode.

The refrigeration circuit <NUM> can operate according to generally known principles. The refrigeration circuit <NUM> can be configured to heat or cool a liquid process fluid (e.g., a heat transfer fluid or medium (e.g., a liquid such as, but not limited to, water or the like)), in which case the refrigeration circuit <NUM> may be generally representative of a liquid chiller system. The refrigeration circuit <NUM> can alternatively be configured to heat or cool a gaseous process fluid (e.g., a heat transfer medium or fluid (e.g., a gas such as, but not limited to, air or the like)), in which case the refrigeration circuit <NUM> may be generally representative of an air conditioner or heat pump.

In operation, the compressor <NUM> compresses a working fluid (e.g., a heat transfer fluid (e.g., refrigerant or the like)) from a relatively lower pressure gas to a relatively higher-pressure gas. The relatively higher-pressure gas is also at a relatively higher temperature, which is discharged from the compressor <NUM> and flows through the condenser <NUM>. In accordance with generally known principles, the working fluid flows through the condenser <NUM> and rejects heat to the process fluid (e.g., water, air, etc.), thereby cooling the working fluid. The cooled working fluid, which is now in a liquid form, flows to the expansion device <NUM>. The expansion device <NUM> can be but is not limited to for example an expansion valve, orifice, expander, or the like. The expansion device <NUM> reduces the pressure of the working fluid. As a result, a portion of the working fluid is converted to a gaseous form. The working fluid, which is now in a mixed liquid and gaseous form flows to the evaporator <NUM>. The working fluid flows through the evaporator <NUM> and absorbs heat from the process fluid (e.g., a heat transfer medium (e.g., water, air, etc.)), heating the working fluid, and converting it to a gaseous form. The gaseous working fluid then returns to the compressor <NUM>. The above-described process continues while the refrigeration circuit is operating, for example, in a cooling mode (e.g., while the compressor <NUM> is enabled).

<FIG> is a perspective view of a multi-slab microchannel heat exchanger <NUM>, according to an embodiment. The multi-slab microchannel heat exchanger <NUM> includes a slab <NUM> and a slab <NUM>. The slab <NUM> includes a plurality of microchannel tubes 21A. In an embodiment, the tubes can be flat multiport tubes. The slab <NUM> also includes an inlet header <NUM> and an outlet header (behind the inlet header <NUM>). An inlet conduit (e.g., pipe) 27A is connected to the inlet header <NUM> via an inlet connector 29A. An outlet conduit (e.g., pipe) 27B is connected to the outlet header of the slab <NUM> via an outlet connector 29B. In an embodiment, the inlet header <NUM>, the outlet header of the slab <NUM>, the inlet connector 29A, and outlet connector 29B are made of aluminum or aluminum alloys. In an embodiment, the inlet pipe 27A and the outlet pipe 27B are made of copper or copper alloys. It will be appreciated that the copper-aluminum transition joints (where the inlet pipe 27A and the inlet connector 29A converge and where the outlet pipe 27B and the outlet connector 29B converge) are protected or covered from corrosion (to prevent copper ions contained within the condensate to reach the aluminum part of the heat exchanger due to corrosion concerns).

The slab <NUM> also includes a bracket 25A. In an embodiment, the bracket 25A can be a flat plate made of aluminum or aluminum alloys extended in a height (H) direction of the heat exchanger <NUM>. The bracket 25A is fixed to the last tube (the tube at the right end of the slab <NUM> in a length (L) direction of the slab <NUM>, which can be a reinforcement tube) of the slab <NUM>. The slab <NUM> further includes an end support 26A. The end support 26A can be a flat plate extended in the height (H) direction of the heat exchanger <NUM>. The end support 26A is fixed to the first tube (the tube at the left end of the slab <NUM> in the length (L) direction of the slab <NUM>, which can be a reinforcement tube) of the slab <NUM>. The differences between the end support 26A and the bracket 25A include: (<NUM>) the end support 26A is at an end of the heat exchanger <NUM> in the length (L) direction of the heat exchanger <NUM> while the bracket 25A is between the slabs <NUM> and <NUM>. For example, the bracket 25A can be in the middle of the heat exchanger <NUM>; (<NUM>) the bracket 25A includes joint assembly (e.g., bolt(s) and nut(s)) to fixedly connect to another bracket 25B of the slab <NUM> while the end support 26A has an L-shape (see 230A in <FIG>) and has joint assembly to fixedly connect the heat exchanger <NUM> to the refrigeration circuit since the end support 26A is at the end of the heat exchanger <NUM>; and (<NUM>) the end support 26A can have a thickness (in the length (L) direction of the heat exchanger <NUM>) greater than a thickness of the bracket 25A to serve as a part of a frame of the heat exchanger <NUM>.

The slab <NUM> and the slab <NUM> are mirror images (from the reference point at brackets 25A, 25B) of each other. The slab <NUM> includes a bracket 25B (which can be made of aluminum or aluminum alloys), a plurality of microchannel tubes 22A, an inlet header <NUM>, an end support 26B, and an outlet header (behind the inlet header <NUM>). An inlet conduit (e.g., pipe) 28A is connected to the inlet header <NUM> via an inlet connector 29C. An outlet conduit (e.g., pipe, behind inlet pipe 28A) of the slab <NUM> is connected to the outlet header of the slab <NUM> via an outlet connector (behind the inlet connector 29C). In an embodiment, the components of the slab <NUM> are the same as or similar to the structures and/or functions and/or materials of the components of the slab <NUM>. The end supports 26A, 26B can be made of aluminum or aluminum alloys. The slab <NUM> and the slab <NUM> converge at a middle point (at the location of brackets 25A, 25B) of the heat exchanger <NUM>.

The embodiment disclosed in <FIG> can put the refrigerant connections on a near (left) side and a far (right) side of the heat changer <NUM> (leaving the refrigerant connections on the outer edges of the heat exchanger <NUM>), and may cause issues in a production or service or maintenance environment. Copper piping (see dotted lines in <FIG>) may be utilized to span the required distance to bring the far side refrigerant connection to the near side to allow refrigerant to flow to the slabs on both sides. For example, copper piping can route refrigerant to inlet pipes 27A and 28A via, e.g., a common inlet conduit (e.g., pipe). Copper piping can also route refrigerant from the outlet pipe 27B and the outlet pipe of the slab <NUM> to, e.g., a common outlet conduit (e.g., pipe). The copper piping needs to be isolated/insulated as to not allow copper ions contained within the condensate to reach the aluminum of the heat exchanger <NUM> due to corrosion concerns. That is, the copper piping needs to be insulated to ensure no condensate can fall from the copper piping (onto the aluminum heat exchanger slabs) carrying copper ions that could corrode the heat exchanger. The entire process (production or service or maintenance) can be labor intensive and costly.

<FIG> is a perspective view of a multi-slab microchannel heat exchanger <NUM>, according to another embodiment. <FIG> is a front view of the multi-slab microchannel heat exchanger <NUM>, according to an embodiment.

The multi-slab microchannel heat exchanger <NUM> includes a slab <NUM> and a slab <NUM>. The slab <NUM> includes a plurality of microchannel tubes 210A (see also <FIG> and <FIG>). In an embodiment, the tubes 210A can be flat multiport tubes extending in a height (H) direction of the heat exchanger <NUM>. The plurality of tubes of the slab <NUM> is arranged successively in a direction along a length (L1) of the heat exchanger <NUM>. The slab <NUM> also includes an inlet header <NUM> and an outlet header <NUM>.

An inlet conduit (e.g., pipe) <NUM> is connected to the inlet header <NUM> via an inlet connector 299A. An outlet conduit (e.g., pipe) <NUM> is connected to the outlet header <NUM> via an outlet connector 299B. In an embodiment, the inlet pipe <NUM> and the outlet pipe <NUM> extend in a vertical direction along a height (H) direction of the heat exchanger <NUM>. The inlet connector 299A and the outlet connector 299B are disposed at the left end of the heat exchanger <NUM>. In one embodiment, the inlet connector 299A can extend (from the connection with the inlet pipe <NUM>) vertically in the height (H) direction and then bend and then extend horizontally in the length (L1) direction to connect to the inlet header <NUM>. In one embodiment, the outlet connector 299B can extend (from the connection with the outlet pipe <NUM>) vertically in the height (H) direction and then bend and then extend horizontally in the length (L1) direction to connect to the outlet header <NUM>. In one embodiment, L1 is equal to L2. In another embodiment, L1 is not equal to L2.

The heat exchanger <NUM> as illustrated in <FIG> can be a two-pass heat exchanger. In operation, heat transfer fluid (e.g., refrigerant or the like) flows through into the inlet pipe <NUM>, into the inlet header <NUM> via the inlet connector 299A, into and through the plurality of microchannel tubes of the slab <NUM> first upwardly from a bottom to a top of the heat exchanger <NUM> in the height (H) direction and then downwardly from the top to the bottom of the heat exchanger <NUM> in the height (H) direction, into the outlet header <NUM>, and then into the outlet pipe <NUM> via the outlet connector 299B.

In operation, heat transfer fluid (e.g., refrigerant or the like) flows through into the inlet pipe <NUM>, into the inlet header <NUM> via the inlet connector 299A, into and through the plurality of microchannel tubes 210A of the slab <NUM> first upwardly from a bottom to a top of the heat exchanger <NUM> in the height (H) direction and then downwardly from the top to the bottom of the heat exchanger <NUM> in the height (H) direction, into the outlet header <NUM>, and then into the outlet pipe <NUM> via the outlet connector 299B.

Each of the inlet header <NUM> and the outlet header <NUM> has a length L1 (the length of the slab <NUM>), extends from the left end of the slab <NUM> to the right end of the slab <NUM> in the length direction of the heat exchanger <NUM>, and is located at the bottom of the heat exchanger <NUM>.

In an embodiment, the inlet header <NUM>, the outlet header <NUM>, the inlet connector 299A, and outlet connector 299B are made of aluminum or aluminum alloys. In an embodiment, the inlet pipe <NUM> and the outlet pipe <NUM> are made of copper or copper alloys. It will be appreciated that the copper-aluminum transition joints (where the inlet pipe <NUM> and the inlet connector 299A converge and where the outlet pipe <NUM> and the outlet connector 299B converge) are protected or covered from corrosion (to prevent copper ions contained within the condensate to reach the aluminum part of the heat exchanger <NUM> due to corrosion concerns).

The slab <NUM> also includes a bracket 240A. In an embodiment, the bracket 240A can be a flat plate made of aluminum or aluminum alloys, extending vertically from a top to a bottom of the heat exchanger <NUM> in the height (H) direction of the heat exchanger <NUM>. The bracket 240A is fixed to the last tube (the tube at the right end of the slab <NUM> in a length (L1) direction of the slab <NUM>, which can be a reinforcement tube for attachment purpose) of the slab <NUM>. The slab <NUM> further includes an end support 230A. The end support 230A can be a flat plate extending vertically from a top to a bottom of the heat exchanger <NUM> in the height (H) direction of the heat exchanger <NUM>. The end support 230A is fixed to the first tube (the tube at the left end of the slab <NUM> in the length (L) direction of the slab <NUM>, which can be a reinforcement tube for attachment purpose) of the slab <NUM>. The differences between the end support 230A and the bracket 240A include: (<NUM>) the end support 230A is at an end of the heat exchanger <NUM> in a length (L) direction of the heat exchanger <NUM> while the bracket 240A is at an end of the slab <NUM> and between the slab <NUM> and slab <NUM>, for example the bracket 240A can be in the middle of the heat exchanger <NUM>; (<NUM>) the bracket 240A includes joint assembly (e.g., bolt(s) and nut(s)) to fixedly connect to another bracket (e.g., 240B on slab <NUM>) while the end support 230A has an L-shape and has joint assembly to fixedly connect the heat exchanger <NUM> to the refrigeration circuit since the end support 230A is at the end of the heat exchanger <NUM>; and (<NUM>) the end support 230A can have a thickness (in the length (L1) direction of the slab <NUM>) greater than a thickness of the bracket 240A so that the end support 230A can serve as a part of a frame of the heat exchanger <NUM>.

The slab <NUM> includes a plurality of microchannel tubes 220A (see also <FIG> and <FIG>). In an embodiment, the tubes can be flat multiport tubes extending in a height (H) direction of the heat exchanger <NUM>. The plurality of tubes of the slab <NUM> is arranged successively in a direction along a length (L2) of the heat exchanger <NUM>. The slab <NUM> also includes an inlet header <NUM> and an outlet header <NUM>.

An inlet conduit (e.g., pipe) <NUM> is connected to the inlet header <NUM> via an inlet connector 299C. An outlet conduit (e.g., pipe) <NUM> is connected to the outlet header <NUM> via an outlet connector 299D. In an embodiment, the inlet pipe <NUM> and the outlet pipe <NUM> extend in a vertical direction along a height direction of the heat exchanger <NUM>. The inlet connector 299C and the outlet connector 299D are disposed at the left end of the heat exchanger <NUM>. In one embodiment, the inlet connector 299C can extend (from the connection with the inlet pipe <NUM>) vertically in the height (H) direction and then bend and then extend horizontally in the length (L2) direction to connect to the inlet header <NUM>. In one embodiment, the outlet connector 299D can extend (from the connection with the outlet pipe <NUM>) vertically in the height (H) direction and then bend and then extend horizontally in the length (L2) direction to connect to the outlet header <NUM>. In an embodiment, the inlet connector 299C and the outlet connector 299D can extend a length L1 in the longitudinal direction (parallel to the inlet/outlet headers) of the heat exchanger <NUM> and fluidly connect to the inlet header <NUM> and the outlet header <NUM> (at a location in the middle of the heat exchanger <NUM> in the length direction), respectively.

In operation, heat transfer fluid (e.g., refrigerant or the like) flows through into the inlet pipe <NUM>, into the inlet header <NUM> via the inlet connector 299C, into and through the plurality of microchannel tubes 220A of the slab <NUM> first upwardly from a bottom to a top of the heat exchanger <NUM> in the height (H) direction and then downwardly from the top to the bottom of the heat exchanger <NUM> in the height (H) direction, into the outlet header <NUM>, and then into the outlet pipe <NUM> via the outlet connector 299D.

A common inlet conduit (e.g., pipe) can route refrigerant (from, e.g., an expansion device or a compressor) to the inlet pipes <NUM> and <NUM>, and a common outlet conduit (e.g., pipe) can route refrigerant from the outlet pipes <NUM> and <NUM> (to e.g., a compressor or an expansion device of the refrigeration circuit).

Each of the inlet header <NUM> and the outlet header <NUM> has a length L2 (the length of the slab <NUM>), extends from the left end of the slab <NUM> to the right end of the slab <NUM> in the length direction of the heat exchanger <NUM>, and is located at the bottom of the heat exchanger <NUM>.

In an embodiment, the inlet header <NUM>, the outlet header <NUM>, the inlet connector 299C, and outlet connector 299D are made of aluminum or aluminum alloys. In an embodiment, the inlet pipe <NUM> and the outlet pipe <NUM> are made of copper or copper alloys. It will be appreciated that the copper-aluminum transition joints (where the inlet pipe <NUM> and the inlet connector 299C converge and where the outlet pipe <NUM> and the outlet connector 299D converge) are protected or covered from corrosion (to prevent copper ions contained within the condensate to reach the aluminum part of the heat exchanger <NUM> due to corrosion concerns).

It will be appreciated that disposing the inlet/outlet connecters/headers or the piping of the inlet/outlet connecters/headers under the slab(s) (at the bottom of the slab(s)), and/or making the inlet/outlet connecters/headers or the piping of the inlet/outlet connecters/headers using aluminum or aluminum alloys can help with reducing/eliminating corrosion (to prevent copper ions contained within the condensate to reach the aluminum part of the heat exchanger due to corrosion concerns). The inlet/outlet connecters or the piping of the inlet/outlet connecters can be fixedly connected to the inlet/outlet pipe(s) and/or the inlet/outlet headers by various means of attachment, including straps and post-process welding, blocks of aluminum either welded or strapped, or plastic wire ties, etc..

The slab <NUM> also includes a bracket 240B. In an embodiment, the bracket 240B can be a flat plate made of aluminum or aluminum alloys, extending vertically from a top to a bottom of the heat exchanger <NUM> in the height (H) direction of the heat exchanger <NUM>. The bracket 240B is fixed to the first tube (the tube at the left end of the slab <NUM> in the length (L2) direction of the slab <NUM>, which can be a reinforcement tube for attachment purpose) of the slab <NUM>. The slab <NUM> further includes an end support 230B. The end support 230B can be a flat plate extending vertically from a top to a bottom of the heat exchanger <NUM> in the height direction of the heat exchanger <NUM>. The end support 230B is fixed to the last tube (the tube at the right end of the slab <NUM> in the length (L2) direction of the slab <NUM>, which can be a reinforcement tube for attachment purpose) of the slab <NUM>. The differences between the end support 230B and the bracket 240B include: (<NUM>) the end support 230B is at an end of the heat exchanger <NUM> in a longitudinal direction of the heat exchanger <NUM> while the bracket 240B is at an end of the slab <NUM> and between the slab <NUM> and <NUM>, for example the bracket 240B can be in the middle of the heat exchanger <NUM>; (<NUM>) the bracket 240B includes joint assembly (e.g., bolt(s) and nut(s)) to fixedly connect to another bracket (e.g., 240A of the slab <NUM>) while the end support 230B has an L-shape and has joint assembly to fixedly connect the heat exchanger <NUM> to the refrigeration circuit since the end support 230B is at the end of the heat exchanger <NUM>; and (<NUM>) the end support 230B can have a thickness (in the length (L2) direction) greater than a thickness of the bracket 240B so that the end support 230B can serve as a part of a frame of the heat exchanger <NUM>. The slab <NUM> and the slab <NUM> converge at a middle point (at the location of brackets 240A, 240B) of the heat exchanger <NUM>.

It will be appreciated that when there are more than two slabs, and all the slabs are arranged successively in the direction along the length (L <NUM>, L2) of the heat exchanger, each slab at the two ends (in the longitudinal direction) of the heat exchanger has an end support at one end of the slab and a bracket at the other end of the slab, and each slab in the middle of the heat exchanger has a bracket at one end of the slab and another bracket at the other end of the slab.

In an embodiment, the inlet connectors and the outlet connectors of the plurality of slabs of the heat exchanger are disposed at a same/single end of the heat exchanger. In an embodiment, the inlet connectors and the outlet connectors of the plurality of slabs of the heat exchanger are disposed at a bottom of the same/single end of the heat exchanger. In an embodiment, the inlet pipes, the outlet pipes, the inlet connectors, and the outlet connectors of the plurality of slabs of the heat exchanger are disposed at the same/single end of the heat exchanger. In an embodiment, the inlet headers and the outlet headers of the plurality of slabs of the heat exchanger are disposed at the bottom of the heat exchanger.

<FIG> is a side sectional view of a plurality of microchannel tubes <NUM> in fluid communication with a header <NUM>, according to an embodiment. The adjacent tubes <NUM> generally have fan-fold fins <NUM> brazed in between. Refrigerant can be distributed into the micro-channel tubes <NUM> from the header <NUM>, or into the header <NUM> from micro-channel tubes <NUM>. Outer surfaces of the micro-channel tubes <NUM> and the fins <NUM> may help heat exchange between the refrigerant (working fluid) in the micro-channel tubes <NUM> and the environment (e.g., process fluid such as air or water). It will be appreciated that the header <NUM> can be the inlet header or the outlet header described in <FIG> and <FIG>. It will also be appreciated that the microchannel tubes <NUM> can be the microchannel tubes described in <FIG> and <FIG>.

<FIG> is a diagrammatic view of a slab (see <NUM> and <NUM> of <FIG>) <NUM> of a multi-slab microchannel heat exchanger, according to an embodiment. As illustrated in <FIG>, an inlet header <NUM> of the heat exchanger is in fluid communication with the inlet <NUM> of each tube <NUM> of the plurality of tubes of the slab <NUM>. An outlet header <NUM> of the heat exchanger is in fluid communication with the outlet <NUM> of each tube <NUM> of the plurality of tubes of the slab <NUM>. The tube <NUM> has microchannels or small pathways for gas or liquid (e.g., refrigerant) to pass through. The microchannels have inlets and outlets. The inlet <NUM> of each tube <NUM> of the plurality of tubes is in fluid communication with the outlet <NUM> of each tube <NUM> of the plurality of tubes through the microchannels of the tube <NUM>.

<FIG> is a structural schematic diagram of a multi-slab microchannel heat exchanger <NUM>, according to an embodiment. The heat exchanger <NUM> includes a slab <NUM> having a plurality of microchannel tubes 410A, an inlet header <NUM>, and an outlet header <NUM>; and a slab <NUM> having a plurality of microchannel tubes 420A, an inlet header <NUM> and an outlet header <NUM>. The heat exchanger <NUM> is a single pass heat exchanger. The arrows indicate the direction of the flow of the heat transfer fluid. The inlet/outlet pipes and the inlet/outlet connectors are not shown. It will be appreciated that the heat exchanger <NUM> of <FIG> can have the same/similar components as the heat exchanger <NUM> of <FIG>, except that the heat exchanger <NUM> is a single pass heat exchanger while the heat exchanger <NUM> is a two-pass heat exchanger. It will also be appreciated that in <FIG>, the inlet pipes and the inlet connectors can have the same/similar configuration as the outlet pipes and the outlet connectors, except that the inlet pipes and the inlet connectors are disposed at the bottom of the heat exchanger <NUM> while the outlet pipes and the outlet connectors are disposed at the top of the heat exchanger <NUM> or vice versa.

<FIG> is a structural schematic diagram of a multi-slab microchannel heat exchanger <NUM>, according to another embodiment. The heat exchanger <NUM> includes a slab <NUM> having a plurality of microchannel tubes <NUM>10A, an inlet header 560A, and an outlet header 540A; a slab <NUM> having a plurality of microchannel tubes 520A, an inlet header 560B, and an outlet header 540B; and a slab <NUM> having a plurality of microchannel tubes 530A, an inlet header 560C, and an outlet header 540C. The heat exchanger <NUM> also includes inlet connectors 550A, 550B, 550C fluidly connected to the inlet headers 560C, 560B, and 560A, respectively. The inlet connectors 550A, 550B, 550C can have the same/similar configuration as the inlet connectors 299A, 299C of <FIG>. The outlet pipe (not shown) and the outlet connector (not shown) of <FIG> can have the same/similar configuration as the outlet pipes <NUM>, <NUM> of <FIG> and the outlet connectors 299B, 299D of <FIG>. The heat exchanger <NUM> is a single pass heat exchanger. The arrows indicate the direction of the flow of the heat transfer fluid.

<FIG> is a structural schematic diagram of a multi-slab microchannel heat exchanger <NUM>, according to yet another embodiment. The heat exchanger <NUM> includes a slab <NUM> having a plurality of microchannel tubes 610A and an inlet header <NUM> and an outlet header (behind the inlet header <NUM>), a slab <NUM> having a plurality of microchannel tubes 620A and an inlet header <NUM> and an outlet header (behind the inlet header <NUM>), and a slab <NUM> having a plurality of microchannel tubes 630A and an inlet header <NUM> and an outlet header (behind the inlet header <NUM>). The heat exchanger <NUM> also includes inlet connectors 670C, 670B, and 670A fluidly connected to the inlet headers <NUM>, <NUM>, and <NUM>, respectively. The outlet connectors are not shown. The components of the heat exchanger <NUM> are the same as or similar to the components disclosed in <FIG> and <FIG>. For example, the inlet connectors 670A, 670B, and 670C can have the same/similar configuration as the inlet connectors 299A, 299C of <FIG>. The outlet connectors of <FIG> can have the same/similar configuration as the outlet connectors 299B, 299D of <FIG>. The arrows (solid arrow: in, dotted arrow: out) indicate the direction of the flow of the heat transfer fluid. The heat exchanger <NUM> is a two-pass heat exchanger. It will be appreciated that <FIG> can have the same/similar components as <FIG>, except that <FIG> has three slabs while <FIG> has two slabs. It will also be appreciated that <FIG> can have the same/similar components as <FIG>, except that the heat exchanger <NUM> is a single pass heat exchanger while the heat exchanger <NUM> is a two-pass heat exchanger.

<FIG> is a schematic sectional view of concentric conduits <NUM>, <NUM>, according to an embodiment. The conduit710 is disposed inside the conduit <NUM>. In an embodiment, the conduit <NUM> extends/runs concentric with the conduit <NUM>.

In an embodiment, the conduit <NUM> can be an inlet connector (e.g., the far side inlet connector 299C of <FIG>), and the conduit <NUM> can be an inlet header (e.g., the near side inlet header <NUM> of <FIG>). In an embodiment, the conduit <NUM> can be an outlet connector (e.g., the far side outlet connector 299D of <FIG>), and the conduit <NUM> can be an outlet header (e.g., the near side outlet header <NUM> of <FIG>).

In an embodiment, the conduit <NUM> can be an inlet connector (e.g., the far side inlet connector 299C of <FIG>), and the conduit <NUM> can be an outlet connector (e.g., the far side outlet connector 299D of <FIG>). In an embodiment, the conduit <NUM> can be an outlet connector (e.g., the far side outlet connector 299D of <FIG>), and the conduit <NUM> can be an inlet connector (e.g., the far side inlet connector 299C of <FIG>). These embodiments can also be referred to as being arranged in an "internal heat exchanger" (e.g., exchanging heat between the inlet two-phase pipe/line and the outlet vapor pipe/line when one pipe/line is disposed inside the other pipe/line) fashion.

Testing shows that with the addition of an internal heat exchanger in the connecting lines/pipes of a slab of the multi-slab microchannel heat exchanger, the performance of the refrigeration circuit can be improved/enhanced by at or about <NUM>%.

Embodiments disclosed herein meet a long-felt but unsatisfied need of reducing manufacturing and maintenance/service cost, reducing physical labor burden, and mitigating corrosion concerns of copper ions in condensate falling on aluminum, in an oversized/multi-slab microchannel heat exchanger.

It will be appreciated that typically in manufacturing an oversized/multi-slab microchannel heat exchanger, there was a need for additional copper piping to be routed around the heat exchanger for a far side refrigeration connection as well as the insulation of this copper piping from the aluminum (to avoid corrosion). It will also be appreciated that the additional copper piping was used because there is no good method to fix/join aluminum piping, aluminum piping tends to move easily (not stable), etc. Embodiments disclosed herein allow all refrigerant line connections to be made in a production environment to be on a single side of the heat exchanger. Embodiments disclosed herein allow routing the refrigerant piping to a far side slab in an efficient manner for high volume production, and/or removing the physical labor burden of insulating copper piping above the aluminum heat exchanger to mitigate corrosion concerns of copper ions in condensate falling on aluminum, and/or reducing assembly labor cost (due to less connection points in manufacturing).

It will also be appreciated that typically during maintenance/service of the oversized / multi-slab microchannel heat exchanger, typically the location a service person operate is at the near side. When the connections of the components (such as the inlet/outlet connectors) are made at the near side during manufacturing (as in the embodiments disclosed herein), labor reduction during maintenance/service can be achieved due to less connection points and due to the convenient location of service for the heat exchanger.

The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms "a," "an," and "the" include the plural forms as well, unless clearly indicated otherwise. The terms "comprises" and/or "comprising," when used in this specification, specify the presence of the 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, elements, and/or components.

Claim 1:
A multi-slab microchannel heat exchanger (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a first slab (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the first slab comprising:
a first inlet header (<NUM>, <NUM>, <NUM>, <NUM>, 560A, <NUM>);
a first outlet header (<NUM>, <NUM>, <NUM>, <NUM>, 540A); and
a first plurality of tubes (21A, 210A, 410A, 510A, 610A),
wherein the first plurality of tubes is arranged successively in a direction along a length (L) of the heat exchanger,
each of the first plurality of tubes includes microchannels, the first plurality of tubes includes inlets (<NUM>) and outlets (<NUM>), the inlets of the first plurality of tubes are in fluid communication with the outlets of the first plurality of tubes through the microchannels of the plurality of tubes, and
the first inlet header is in fluid communication with the inlets of the first plurality of tubes, the first outlet header is in fluid communication with the outlets of the first plurality of tubes;
a second slab (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) including a second inlet header (<NUM>, <NUM>, <NUM>, 560B, <NUM>) and a second outlet header (<NUM>, <NUM>, <NUM>, 540B), the direction of the length of the heat exchanger being a direction extending from the first slab to the second slab;
a first inlet connector (299A, 550A, 670C) fluidly connected to the first inlet header;
a first outlet connector (299B) fluidly connected to the first outlet header;
a second inlet connector (299C, 550B, 670B) fluidly connected to the second inlet header; and
a second outlet connector (299D) fluidly connected to the second outlet header,
wherein the first slab and the second slab are arranged successively in the direction along the length of the heat exchanger,
the heat exchanger has a first end and a second end in the direction of the length of the heat exchanger,
characterized in that the first inlet connector, the first outlet connector, the second inlet connector, and the second outlet connector are disposed at the first end of the heat exchanger.