Fluid Distributor for a Shell-And-Tube Flooded Evaporator

This patent application claims the benefit of U.S. Provisional Patent Application No. 63/653,104, filed on May 29, 2024, which is incorporated by reference herein in its entirety.

Embodiments described herein relate to the field of flooded evaporators, and more particularly, to a fluid distributor for a shell-and-tube flooded evaporator.

Described herein is a distributor for a shell-and-tube flooded evaporator. The distributor comprises a first header comprising one or more first outlets located along a length at a bottom side of the first header, and a second header comprising one or more second outlets located along a length at a bottom side of the second header, wherein the first header and the second header are configured to be disposed within a shell associated the evaporator such that the first header and the second header extend along a length, on opposite sides of an inner wall, of the shell, and the first header and the second header are fluidically connected to one or more refrigerant inlet tubes provided on the shell.

In one or more embodiments, the distributor is configured to receive a refrigerant within the first header and/or the second header and allow the refrigerant to flow along the length of the first header and the second header and flow within the shell in a downward direction via the corresponding first and second outlets.

In one or more embodiments, the second header is fluidically connected to the first header via one or more connection ports extending between the first header and the second header, wherein the distributor is configured to receive a refrigerant within the first header and supply the refrigerant into the second header via the one or more connection ports.

In one or more embodiments, the distributor is disposed at a bottom portion of the shell, wherein the distributor is configured at a predefined height from a bottom-most point of the shell.

In one or more embodiments, the distributor is disposed within the shell such that a first set of tubes of a plurality of tubes associated with the evaporator remains or extends below the distributor.

In one or more embodiments, the distributor is disposed within the shell such that a plurality of tubes associated with the evaporator remains or extends above the one or more connection ports or the distributor.

In one or more embodiments, a first side of each of the first header and the second header are oriented at a first predefined angle, in opposite directions, with respect to a plane extending tangentially along a bottom-most point of the shell, and wherein the one or more connection ports extend parallel to the plane.

In one or more embodiments, the first predefined angle is greater than or equal to 20 degrees.

In one or more embodiments, a second side, opposite to the first side, of each of the first header and the second header are oriented at a second predefined angle with respect to the plane.

In one or more embodiments, the one or more first outlets of the first header are configured at a third predefined angle with respect to a longitudinal axis and/or transverse axis of the first header and the one or more second outlets of the second header are configured at a fourth predefined angle with respect to the longitudinal axis and/or transverse axis of the first header.

In one or more embodiments, the one or more connection ports are a hollow member having a rectangular profile or square profile.

In one or more embodiments, the one or more connection ports are located adjacent to or in-line with an inlet of the first header or the inlet tube.

In one or more embodiments, the one or more connection ports comprise a connection port centrally located between the first header and the second header such that the connection port extends orthogonally to a longitudinal axis of the first header and the second header.

In one or more embodiments, an end, adjacent to the first header, of the connection port has a bell-shaped inlet, wherein a cross-section of the bell-shaped inlet reduces while moving in a direction toward the connection port.

In one or more embodiments, another end, adjacent to the second header, of the connection port has a bell-shaped outlet, wherein a cross-section of the bell-shaped outlet increases while moving in a direction away from the corresponding connection port.

In one or more embodiments, the one or more connection ports extend orthogonally between a bottom end of the first header and the second header.

In one or more embodiments, the one or more connection ports extend orthogonally between a top end of the first header and the second header.

In one or more embodiments, the one or more connection ports extend orthogonally between a middle section, of the first header and the second header.

In one or more embodiments, at least one set of tubes of the plurality of tubes are of different type or have different dimensions compared to the remaining tubes among the plurality of tubes.

In one or more embodiments, the one or more first outlets and the one or more second outlets are in line.

In one or more embodiments, the one or more first outlets and the one or more second outlets are offset from each other.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, features, and techniques of the subject disclosure will become more apparent from the following description taken in conjunction with the drawings.

The following is a detailed description of embodiments of the subject disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the subject disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject disclosure as defined by the appended claims.

Various terms are used herein. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the subject disclosure, the components of this disclosure. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” “first”, “second” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, described herein may be oriented in any desired direction.

A chiller or refrigeration system removes heat from a coolant liquid (may be water or brine) via a vapor-compression or refrigeration cycle. This coolant liquid may then be circulated through a heat exchanger to cool spaces or equipment, or another process stream (such as air or process water). A typical chiller comprises an evaporator, a compressor, a condenser, and an expansion device. Each works together to efficiently transfer heat. In chillers, a flooded evaporator may be employed. Unlike a dry evaporator, where the refrigerant largely vaporizes inside the tubes, in a flooded evaporator, the tubes are immersed in liquid refrigerant. The coolant liquid flows inside the tube that is to be cooled. This design allows for improved heat transfer, as the liquid refrigerant fully envelops the heat exchange tubes, absorbing heat more efficiently. The colder coolant liquid is used to cool the desired space or process stream.

The process begins with the refrigerant absorbing heat from the process fluid, causing the refrigerant to boil and vaporize. This phase change is what effectively removes heat from the system being cooled. The vaporized refrigerant then flows from the flooded evaporator to the compressor. The compressor may increase the pressure of the refrigerant vapor. This process of compression raises the temperature of the refrigerant, preparing it for the next phase of the cycle. The high-pressure, high-temperature vapor may then be directed to the condenser.

In the condenser, the refrigerant vapor may release the absorbed heat to the surroundings, typically air or water. As the refrigerant cools, it condenses into a high-pressure liquid. Finally, the high-pressure liquid refrigerant may flow into the expansion device. The expansion device, which can be a valve or an orifice, may control the flow of refrigerant into the flooded evaporator. As the refrigerant passes through the expansion device, its pressure drops dramatically, leading to a reduction in temperature. This cold, low-pressure liquid refrigerant may re-enter the flooded evaporator, ready to absorb more heat and continue the refrigeration cycle.

As a two-phase refrigerant (mixture of liquid refrigerant and gaseous/vaporous refrigerant) enters an inlet of the evaporator, a fluid distributor may be employed in the flooded evaporator to evenly distribute the liquid portion of the refrigerant across the tubes carrying coolant liquid such as but not limited to water or brine.

In conventional shell-and-tube type flooded evaporators used in chillers, the fluid distributor is located at the bottom of the shell. This configuration necessitates that the inlet for the refrigerant, or the entry point into the shell, also be positioned at the bottom. Such a design approach may impose several limitations and inefficiencies. Since the liquid distributor is placed at the bottom part of the shell, the chiller's design needs to accommodate this configuration by increasing the chiller's height. This requirement for additional height not only impacts the spatial footprint and installation flexibility of the chiller but may also increase the cost associated with the chiller's structural design and materials.

Moreover, this may result in a significant inefficiency as no evaporation of the refrigerant occurs in the space between the distributor and the first row of tubes extending within the shell. This may lead to an unnecessary accumulation of liquid refrigerant in this area, thereby increasing the total refrigerant charge required for the chiller to operate effectively. Furthermore, the inefficient use of refrigerant exacerbates energy consumption and operational inefficiency.

Therefore, there is a need to provide a simple, efficient, and cost-effective solution to address the spatial constraints and charge accumulation issue associated with existing flooded evaporators.

Referring to, a fluid distributorfor a shell-and-tube type flooded evaporator(referred to as flooded evaporator or evaporatorhereinafter) is disclosed. In one or more embodiments, the distributormay include a first headercomprising a first inlet-, and one or more first outlets(collectively referred to as first outlets, herein) located at first predefined positions along a length at the bottom side of the first header. The distributormay also include a second headercomprising a first inlet-and one or more second outlets(collectively referred to as second outlets, herein) located at second predefined positions along a length at the bottom side of the second header. In one or more embodiments, the second headermay extend parallel to the first header, where the first headermay be fluidically connected to the second headervia one or more connection ports(collectively referred to as connection portsand individually referred to as connection port, herein) extending orthogonally therebetween. However, in other embodiments, the first headermay extend parallel to the second headerwithout any connection ports connecting the first and second headers,.

As illustrated in, in one or more embodiments, the distributormay be disposed at a bottom portion (BP) within a hollow shellassociated with the evaporatorsuch that the distributorremains at a predefined height (H) from the bottom-most point of the shell, with the first headerand the second headerof the distributorextending along a length or longitudinal axis (A-A′), on opposite sides of an inner wall, of the shelland the connection port(s)extending between the first headerand the second header. Further, as illustrated in, in one or more embodiments, the distributormay be disposed at the bottom portion (BP) within the hollow shellsuch that the first headerand the second headerremain at a predefined height (H) from the bottom-most point of the shell, with the first headerand the second headerof the distributorextending along a length or longitudinal axis (A-A′), on opposite sides of an inner wall, of the shell, without the connection port(s).

The shellmay be a hollow cylindrical enclosure that may comprise one or more inlets at opposite sides of the curved surface and an outletat the top portion of the shell. This outlet of the shellmay be further fluidically connected to the compressor (not shown) associated with the chiller and the inlet(s) of the shellmay be fluidically connected to the expansion valve (not shown) associated with the chiller via one or more refrigerant inlet tube(s). Further, a plurality of heat exchange tubes(referred to as tubesor bundled tubes, hereinafter) may extend longitudinally through the shellas shown in.

It is to be appreciated by a person skilled in the art that as the distributorremains at the predefined height (H) from the bottom-most point (BP) of the shell, this allows at least a (first) set of tubes-A among the tubesassociated with the evaporatorto be disposed below the distributorat a bottom portion of the shellwhere typically liquid refrigerant may accumulate due to gravity, and remaining (second) tubes-B among the tubesassociated with the evaporatorto be disposed above the distributor. As a result, the (first set of) tubes-A in the liquid pool may evaporate the liquid refrigerant at the bottom of the shell, thereby reducing the charge amount in the shell. In addition, this configuration may also allow the use of different types or different dimensions of tubesin the evaporator. Thus, higher-performing tubesmay be used at the bottom portion to promote vigorous boiling of the refrigerant pool at the bottom of the shell. Moreover, as the headers,are at the sides of the shell, the vapor refrigerant formed in the shellmay escape near the side walls of the shellwithout stirring the liquid pool, which may help in lowering liquid or charge carryover toward the compressor. However, in some embodiments, the tubesassociated with the evaporatormay be disposed within the shellsuch that none of tubesremain below the distributoror the connection ports.

Further, the first inlet-of the first headermay be fluidically connected to the refrigerant inlet tubeprovided on one of the sides of the shell, where the side inlet-may help reduce the overall height of the chiller. This inlet tubemay be further fluidically connected to the expansion device associated with the chiller. Accordingly, as shown in, the distributormay receive (cold, low-pressure liquid or two-phase) refrigerant from the expansion device within the first headervia the one of the refrigerant inlet tubesand further supply the received refrigerant into the second headervia the connection ports, allowing the refrigerant to flow along the length of the first headerand the second headerand further flow within the shellin a substantially downward direction via the corresponding first and second outletsof the headers. Similarly, as shown in, when no connection portsare provided between the first headerand the second header, the distributormay receive (cold, low-pressure liquid or two-phase) refrigerant from the expansion device within the first headeras well as the second headervia the refrigerant inlet tubes-,-and further allow the refrigerant to flow along the length of the first headerand the second headerand flow within the shellin a substantially downward direction via the corresponding first and second outlets,of the headers.

In one or more embodiments, the first headerand the second headermay be oriented at a first predefined angle (α, α), in opposite directions, with respect to a plane (P-P′) extending tangentially along the bottom-most point (BP) of the shell. However, the connection portsmay extend parallel to the plane (P-P′). In one or more embodiments, the first predefined angle (α, α) may be greater than or equal to 10 degrees but is not limited to the like.

In one or more embodiments, the headers,may be oriented such that a first side, adjacent to the side wall of the shell, of the first headerand the second headermay remain in line with the inner wall of the shell. In one or more embodiments, the first side (adjacent to the inner side wall) of the headers,may have a substantially curved profile based on a profile of the adjacent inner wall of the shell.

Further, a second side, opposite to the first side, of the first headerand the second headermay have a substantially curved profile or a planar profile that may remain inclined at a second predefined (acute) angle with respect to the plane (P-P′) extending tangentially along the bottom-most point (BP) of the shell. The inclined profile of the second side (adjacent sides) of the first and second header,respectively may help increase the internal space for the tubeswithin the shell, thereby allowing a greater number of tubesto be disposed between the headers or within the shelland further enhancing the heat exchange within the evaporator. However, in other embodiments (not shown), the second side of the first and second headers,may also be parallel to each other or perpendicular to the plane (P-P′).

In one or more embodiments, the first outletsof the first headermay be at a third predefined angle with respect to a longitudinal axis of the first headerand the second outletsof the second headermay be at a fourth predefined angle with respect to a longitudinal axis of the first header. This arrangement may help prevent direct impinging or flow of the liquid refrigerant, supplied within the shellvia the corresponding outlets, on the tubesassociated with the evaporator, thereby preventing any failure or damage to the tubes. In one or more embodiments, the third and fourth predefined angles may be the same. However, they may also be different. As illustrated in, in one or more embodiments, the first outletsand the second outletsmay open in a substantially downward direction towards the bottom of the shellsuch that these outlets remain inclined towards a central region of the shell(or away from the opposite planar sides of the shell). However, in other embodiments (not shown), the first outletsand the second outletsmay also be inclined or open towards the opposite planar sides of the shell.

Further, in one or more embodiments, as illustrated in, the first outletsof the first headerand the second outletsof the second headermay be in line. However, in other embodiments, as illustrated in, the first outletsof the first headerand the second outletsof the second headermay be offset from each other.

In one or more embodiments, the distributormay include at least one connection portthat may have a substantially rectangular profile or substantially square profile. However, in other embodiments, the distributormay include more than one connection portwhich may have a substantially rectangular profile or substantially square profile. Further, in one or more embodiments (not shown), the distributormay include at least one connection portthat may have a cylindrical or cuboidal profile.

In one or more embodiments, the connection port(s)may be centrally located between the second sides of the first headerand the second headeras shown insuch that the connection port(s)extends orthogonally to the longitudinal axis (A-A′) of the first headerand the second header(or the longitudinal axis (A-A′) of the shell). In such embodiments, the connection portsmay be located adjacent to or in line with the inlet-of the first headeror the inlet tube. However, in other embodiments, the connection portsmay also be located at different locations along the length of the first and second headers,. Accordingly, the distributormay receive (cold, low-pressure liquid) refrigerant from the expansion device within the first headervia the inlet tubeand further supply the received refrigerant into the second headervia the connection ports, allowing the refrigerant to flow sideways along the length of the first headerand the second headerand further flow within the shellin a substantially downward direction via the corresponding first and second outletsof the headers.

Further, in one or more embodiments, at least one of the connection portsmay extend orthogonally between the bottom end of the second side of the first headerand the second headeras shown in. Furthermore, in some embodiments (not shown), at least one of the connection portsmay extend orthogonally between the top end of the second side of the first headerand the second header. Furthermore, in some other embodiments (not shown), at least one of the connection portsmay extend orthogonally between a middle section (between the top and bottom end) of the second side of the first headerand the second header. However, in other embodiments (not shown), the connection portsmay also be at any other elevation between the first and second header. It is to be appreciated that the position, dimension, and numbers of the connection portsmentioned above are only exemplary, and these can be changed to different positions, different dimensions, and a higher or lower number without any limitation whatsoever, and all such implementations are well within the scope of the subject disclosure.

Referring to, in one or more embodiments, an end-, adjacent to the first header, of the connection portmay have a bell-shaped inlet, where a cross-section of the bell-shaped inletmay smoothly reduce while moving in a direction towards the connection port. The bell-shaped inletmay facilitate in smooth or laminar flow of the refrigerant from the inlet tubeor the first headerinto the connection port. Further, in one or more embodiments (not shown), another end-, adjacent to the second header, of the connection portmay also have a bell-shaped outlet, where a cross-section of the bell-shaped outlet may increase while moving away from the corresponding connection port, enabling uniform and smooth outflow of the refrigerant into the second header.

While various embodiments herein have been described for the distributorbeing employed in a flooded evaporator, however, the distributormay also be employed in other heat exchangers as well, without any limitations, and all such embodiments are well within the scope of this disclosure.

Thus, this disclosure addresses the spatial constraints and charge accumulation issues associated with existing flooded evaporators, by providing a simple and efficient fluid distributor for flooded evaporators, which uniformly and safely supplies refrigerant across the tubes associated with the shell of the flooded evaporator while maintaining low charge (or lowering charge accumulation) in the shell, keeping the height of the overall chiller lower, and also preventing any charge carry over towards the compressor. Additionally, the distributor allows the use of different types of tubes within the shell and allows these tubes to be positioned at the bottom of the shell. This may help improve the overall heat exchange capability or evaporation process in the evaporator.