Apparatus, system and method for heat exchange

Abstract

The present invention provides an apparatus for heat exchange, comprising: a plurality of fins; and a plurality of heat transfer coil pipes in the form of long-strip-shaped section pipes, wherein the heat transfer coil pipes are arranged in a single array. The fins are arranged substantially vertically along a longitudinal portion of the elongated cross-section tubes, directing incoming convective fluid to all of the elongated cross-section tubes for heat exchange thereon. Further, each elongated cross-section tube of the heat transfer coil has a substantially rectangular cross-section with a rounded edge, or an ovoid or elliptical cross-section, and is configured to be mounted at an inclined angle such that the long axis of the elongated cross-section tube is inclined with respect to the direction of incoming convective fluid flowing through the heat transfer coil. Related systems and methods related to the device are further described.

Description

[0001] Cross - reference to related applications

[0002] This invention claims the priority of Singapore patent application No. 10202251384B, filed on October 14, 2022, the entire disclosure of which is incorporated herein by reference. Technical field

[0003] The present invention relates to heat exchange technology for passive displacement cooling. More specifically, the present invention relates to an apparatus for heat exchange suitable for passive displacement cooling, and related systems and methods. Background art

[0004] Passive displacement cooling involves using natural convective air flow within an indoor or enclosed environment for cooling. This cooling method can cool without relying on mechanical driving devices to continuously push the air flow within the indoor or enclosed environment. Therefore, systems that perform passive displacement cooling are very suitable for on - demand and / or directional cooling within an indoor or enclosed environment.

[0005] However, since passive displacement cooling relies on natural convective air flow, its response time is slow and its refrigeration capacity is low. Therefore, whether it can be widely adopted remains to be seen. Thus, it takes a long time to cool an indoor or enclosed environment.

[0006] In addition, current heat exchange systems used for passive displacement cooling include a heat exchange apparatus for cooling air, which was originally optimized for active cooling and needs to be used in conjunction with a mechanical fan to receive forced convective air flow. In other words, this heat exchange apparatus for cooling air is not suitable for passive displacement cooling because passive displacement cooling requires different design parameters and the cooling is carried out under low - speed air.

[0007] In addition, the fin area used in current heat exchange systems for passive displacement cooling is too large and is redundant for low - speed natural and passive convective flows. This will generate unnecessary viscous forces on the flow, and the downstream heat transfer effect is not significant. The resulting low mass flow rate, combined with a fully developed thermal boundary layer, will have an adverse impact on the cooling capacity and response time. Under cooling conditions, the condensation phenomenon will further exacerbate this problem, and the retention of condensate will increase the flow resistance of the convective air flow.

[0008] Among the techniques related to devices for heat exchange used for passive displacement cooling disclosed in the prior art, it includes the content disclosed by Chen et al. ("Natural Convection in a Plate-Fin Tube Heat Exchanger with Two Horizontal Tubes in a Chimney: Experimental and Numerical Studies", 2019). Among them, a device for heat exchange implemented in a chimney is disclosed. The device includes a plate-fin heat transfer coil in the form of a tubular shape with a circular cross-section.

[0009] Another disclosed technique related to the prior art includes the content disclosed by Unger et al. ("Numerical Optimization of Finned Tube Bundle Heat Exchanger Arrangements for Passive Spent Fuel Storage Pool Cooling to Ambient Air", 2020). Among them, a device for heat exchange used for passive cooling of spent fuel assemblies is disclosed. The device includes a finned tube bundle heat transfer coil, which is composed of tubes with different cross-sections, and these tubes are arranged in a straight configuration or a staggered configuration so as to cool the fluid to the frontmost tube through a vertical pipe.

[0010] However, the techniques in the above prior art still face the above problems when performing passive displacement cooling. Therefore, there is a need for an optimized device, system and corresponding method for heat exchange applicable to natural convection air flow to achieve passive displacement cooling, and further provide a faster response time and a greater cooling capacity, so as to cool an indoor or enclosed environment in a short time. Summary of the Invention

[0011] The present invention aims to provide an optimized device, system and corresponding method for heat exchange applicable to natural convection air flow to achieve passive displacement cooling. To achieve this goal, the present invention provides a device for heat exchange, namely a finned heat transfer coil, which has a heat transfer coil in the form of a plurality of elongated cross-section tubes arranged in a single array, and can be single-row or single-column. Each elongated cross-section tube has: a generally rectangular cross-section with a circular edge, or an oval or elliptical cross-section, and is inclined at a certain angle with respect to the convective air flow guided by the fins of the heat transfer coil.

[0012] Advantageously, the device of the present invention provides a smaller viscous force. Therefore, compared with the traditional configuration, it has a higher mass flow rate and heat transfer rate, and at the same time can shorten the response time.

[0013] Equally advantageously, due to the structure and configuration of the tubes, the device of the present invention provides better condensate discharge performance. Therefore, the viscous effect caused by water retention (especially on the fin surface) is reduced.

[0014] Equally advantageously, the device of the present invention provides a more compact design, thus better adapting to space limitations and having better aesthetics.

[0015] Advantageously, the device of the present invention can reduce the overall size of the tubes of the heat transfer coil, thereby reducing the material cost.

[0016] The present invention aims to provide a device for heat exchange, which includes: a plurality of fins; and a heat transfer coil in the form of a plurality of oblong sectional tubes arranged in a single array. The fins are arranged substantially perpendicular to the longitudinal portion of the oblong sectional tubes, guiding the incoming (flowing-in) convective fluid to all of the oblong sectional tubes for heat exchange on the oblong sectional tubes.

[0017] Preferably, each oblong sectional tube of the heat transfer coil has a substantially rectangular cross-section with rounded edges, or an oval or elliptical cross-section.

[0018] Preferably, the oblong sectional tubes of the heat transfer coil are configured to be installed at an inclined angle so as to be inclined with respect to the direction of the incoming convective fluid flowing through the heat transfer coil.

[0019] Preferably, the range of the inclined angle is approximately 0 degrees to 60 degrees.

[0020] Preferably, the aspect ratio of the oblong sectional tubes of the heat transfer coil ranges from approximately 2:1 to 5:1.

[0021] Preferably, each fin is formed with a plurality of perforations through which the oblong sectional tubes of the heating coil pass.

[0022] The present invention also aims to provide a system for heat exchange, which includes: a device for heat exchange, the device including: a plurality of fins; and a heat transfer coil in the form of a plurality of oblong sectional tubes arranged in a single array; and a duct for accommodating the device. The fins are arranged substantially perpendicular to the longitudinal portion of the oblong sectional tubes, guiding the incoming convective fluid to all of the oblong sectional tubes for heat exchange on the oblong sectional tubes, and allowing the outgoing convective fluid to flow into the duct.

[0023] Preferably, each oblong sectional tube of the heat transfer coil of the device has a substantially rectangular cross-section with rounded edges, or an oval or elliptical cross-section.

[0024] Preferably, the oblong sectional tubes of the heat transfer coil of the device are configured to be installed at an inclined angle so as to be inclined with respect to the direction of the incoming convective fluid flowing through the heat transfer coil.

[0025] Preferably, the inclination angle of the tubes of the heat transfer coil ranges from approximately 0 degrees to 60 degrees.

[0026] Preferably, the aspect ratio of the elongated cross-section tubes of the heat transfer coil of the device ranges from approximately 2:1 to 5:1.

[0027] Preferably, the fins of the device are each formed with a plurality of perforations through which the elongated cross-section tubes of the heating coil pass.

[0028] Preferably, the system further includes a tray disposed adjacent to and below the heat transfer coil to collect condensate formed on the device.

[0029] Preferably, the pipe includes a horizontal portion and a vertical portion that are bent at a substantially right angle relative to each other.

[0030] Preferably, the device is located within the horizontal portion of the pipe and is adjacent to the vertical portion of the pipe.

[0031] Preferably, the vertical portion of the pipe has a length that extends from the vertical portion to a horizontal plane below the horizontal portion.

[0032] The present invention also aims to provide a method for heat exchange, which includes: a step of configuring a device for heat exchange, the device including: a plurality of fins; and a heat transfer coil in the form of a plurality of elongated cross-section tubes arranged in a single array; and a step of configuring a pipe for accommodating the device. The fins of the device are all arranged substantially perpendicular to the longitudinal portion of the elongated cross-section tubes, guiding the incoming convective fluid to all of the elongated cross-section tubes for heat exchange thereon, and causing the outgoing convective fluid to flow into the pipe.

[0033] Preferably, the method further includes: a step of configuring each of the elongated cross-section tubes of the heat transfer coil of the device to have a substantially rectangular cross-section with rounded edges, or an oval or elliptical cross-section.

[0034] Preferably, the method further includes: a step of configuring the elongated cross-section tubes of the heat transfer coil of the device to be installed at an inclination angle so as to be inclined relative to the direction of the incoming convective fluid flowing through the heat transfer coil.

[0035] Preferably, the method further includes: a step of collecting condensate formed on the device by a tray disposed adjacent to and below the device.

[0036] Those skilled in the art will readily understand that the present invention is well suited to achieve the stated objectives and to obtain the stated and inherent objectives and advantages. The embodiments described herein are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] For ease of understanding the present invention, preferred embodiments are shown in the drawings, and upon consideration of the following description, the present invention, its construction and operation, and its many advantages will be readily understood and appreciated by observing these embodiments.

[0038] Figure 1 is a schematic diagram showing a structure that includes at least one heat source and a system for heat exchange for passive displacement cooling within the structure provided by the present invention.

[0039] Figure 2 shows Figure 1 a perspective cross-sectional view of the system shown.

[0040] Figure 3 shows a perspective view of a heat exchange device provided by the present invention, which is located Figure 1 in the system shown.

[0041] Figure 4 shows a cross-sectional side view of a part of a heat exchange system that includes a heat exchange device in the structure of the first embodiment, wherein the elongated cross-sectional tubes of its heat transfer coil are arranged in a single array, and the elongated cross-sectional tubes have: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and are inclined at an angle of approximately 0 degrees.

[0042] Figure 5 shows a cross-sectional side view of a part of a heat exchange system that includes a heat exchange device in the structure of the second embodiment, wherein the elongated cross-sectional tubes of its heat transfer coil are arranged in a single array, and the elongated cross-sectional tubes have: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and are inclined at an angle of approximately 30 degrees.

[0043] Figure 6 shows a cross-sectional side view of a part of a heat exchange system that includes a heat exchange device in the structure of the third embodiment, wherein the elongated cross-sectional tubes of its heat transfer coil are arranged in a single array, and the elongated cross-sectional tubes have: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and are inclined at an angle of approximately 45 degrees.

[0044] Figure 7A cross-sectional side view of a part of a system for heat exchange is shown, the system including a heat exchange device in a fourth embodiment structure, wherein the elongated cross-sectional tubes of its heat transfer coil are arranged in a single array, the elongated cross-sectional tubes having: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and being inclined at an angle of approximately 60 degrees.

[0045] Figure 8 A graph showing the increment of sensible heat transfer (sensible heat transfer rate) and the increment of mass flow rate of one or more simulated system models related to a heat transfer system is shown.

[0046] Figure 9 A cross-sectional side view of a part of a fin of a heat exchange device is shown, which further shows the simulated air isotherms (temperature contours) in the channels of the fin.

[0047] Figure 10 A cross-sectional side view of a part of a first simulated system model for heat exchange is shown, which further shows its air isotherms. The first system model includes a heat exchange device, wherein the elongated cross-sectional tubes of its heat transfer coil are arranged in a single array, the elongated cross-sectional tubes having: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and being inclined at an angle of approximately 0 degrees.

[0048] Figure 11 A cross-sectional side view of a part of a second simulated system model for heat exchange is shown, which further shows its air isotherms. The second system model includes a heat exchange device, wherein the elongated cross-sectional tubes of its heat transfer coil are arranged in a single array, the elongated cross-sectional tubes having: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and being inclined at an angle of approximately 30 degrees.

[0049] Figure 12 A cross-sectional side view of a part of a third simulated system model for heat exchange is shown, which further shows its air isotherms. The third system model includes a heat exchange device, wherein the elongated cross-sectional tubes of its heat transfer coil are arranged in a single array, the elongated cross-sectional tubes having: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and being inclined at an angle of approximately 45 degrees.

[0050] Figure 13A cross-sectional side view showing a part of a fourth system model for heat exchange simulation is further shown with its air isotherms. The fourth system model includes a device for heat exchange, wherein the elongated cross-sectional tubes of its heat transfer coils are arranged in a single array, and the elongated cross-sectional tubes have: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and are inclined at an angle of approximately 60 degrees.

[0051] Figure 14 A cross-sectional side view showing a part of a fifth system model for heat exchange simulation is further shown with its air isotherms. The fifth system model includes a device for heat exchange, wherein the tubes of its heat transfer coils are arranged in a single array and have a circular cross-section.

[0052] Figure 15 A cross-sectional side view showing a part of a sixth system model for heat exchange simulation is further shown with its air isotherms. The sixth system model includes a device for heat exchange, wherein the tubes of its heat transfer coils are arranged in a double-row staggered arrangement and have a circular cross-section.

[0053] Figure 16 A cross-sectional side view showing a part of a seventh system model for heat exchange simulation is further shown with its air isotherms. The seventh system model includes a device for heat exchange, wherein the tubes of its heat transfer coils are arranged in a double-row in-line configuration and have a circular cross-section.

[0054] Figure 17 A cross-sectional side view of a first system model for heat exchange simulation is shown, further showing its velocity vectors.

[0055] Figure 18 A cross-sectional side view of a part of a first system model for heat exchange simulation is shown, further showing its velocity vectors.

[0056] Figure 19 A cross-sectional side view of a part of a second system model for heat exchange simulation is shown, further showing its velocity vectors.

[0057] Figure 20 A cross-sectional side view of a part of a third system model for heat exchange simulation is shown, further showing its velocity vectors.

[0058] Figure 21 A cross-sectional side view of a part of a fourth system model for heat exchange simulation is shown, further showing its velocity vectors.

[0059] Figure 22A cross-sectional side view of a portion of a fifth system model for simulation of heat exchange is shown, further showing its velocity vectors. Detailed Description

[0060] The present invention relates to an apparatus for heat exchange suitable for passive displacement cooling, and related systems and methods. The present invention can also be presented in a variety of different embodiments having common elements.

[0061] According to the concept of the present invention, the apparatus for heat exchange includes: a heat transfer coil having a plurality of elongated cross-sectional tubes; and a plurality of fins arranged perpendicularly along the longitudinal portion of the elongated cross-sectional tubes, wherein the elongated cross-sectional tubes pass through the fins. The elongated cross-sectional tubes are arranged in a single array. Preferably, each elongated cross-sectional tube has: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and is laterally inclined at an angle with respect to the convective air flow guided by the fins. The above-mentioned apparatus for heat exchange can be further implemented in related systems and methods for heat exchange.

[0062] Now, the present invention will be described in more detail by way of examples and with reference to the accompanying drawings. For ease of reference, the same reference numerals or number series will be used in all the drawings when referring to the same or similar features.

[0063] Figure 1 FIG. is a schematic diagram showing a structure 1, which includes at least one heat source 2 and a heat exchange system 3 for an embodiment of passive displacement cooling within the structure 1. Figure 2 FIG. shows a perspective cross-sectional view of the heat exchange system 3 provided by the present invention.

[0064] The structure 1 is preferably a closed structure that generally forms an indoor or enclosed environment. The enclosed structure 1 can be defined as having one or more walls. For example, it can be a room in a building. The structure 1 is also further appropriately partitioned so that convective fluid can form and flow therein.

[0065] The heat source 2 is preferably a biological or non-biological entity or occupant that can be located within the structure 1. Specifically, the heat source 2 is a biological entity or occupant that emits or dissipates heat during biological activities within the structure 1. Alternatively, the heat source 2 is a non-biological entity or occupant that emits or dissipates heat during the execution of its predetermined function.

[0066] The heat exchange system 3 at least includes: a pipe having a horizontal portion 311 and a vertical portion 312, an apparatus 32 for heat exchange, and a tray 33. The system 3 helps to form a circulation of convective fluid within the structure 1 where the heat source 2 is located. Specifically, the system 3 receives hot air as the incoming convective fluid, cools it, and delivers cold air as the discharged convective fluid to the heat source 2.

[0067] Figures 1 to 2 Figures 1 to 2 shows further that the horizontal portion 311 of the pipe, the device 32, and the tray 33 will be located at a higher level (elevated level) within the structure 1, while the heat source 2 is located at the ground level within the structure 1 or at a level below this higher level. The vertical portion 312 of the pipe extends from the higher level to the ground. Thus, it can be said that the pipe of the system 3 has an inverted L-shaped structure, forming a substantially right angle between its horizontal portion 311 and its vertical portion 312.

[0068] Figures 1 to 2 Figures 1 to 2 shows further that the device 32 should be substantially accommodated within the horizontal portion 311 of the pipe and should be arranged therein to be substantially adjacent to and / or proximate to the vertical portion 312 of the pipe. More specifically, the device 32 should be substantially adjacent to and / or proximate to the right angle formed between the horizontal portion 311 and the vertical portion 312 of the pipe. This configuration can prevent the condensate formed on the device 32 from entering the vertical portion 312 of the pipe.

[0069] Figure 1 Figure 1 shows further that the tray 33 should be arranged below the device 32. The tray 33 is used to collect and discharge the condensate formed and dripped by the device 32 so as to discharge it for treatment or reuse.

[0070] Figure 1 Figure 1 shows further the circulation of the convective fluid flow within the structure 1, where the hot air and cold air are respectively marked accordingly. Specifically, the heat dissipated or dispersed by the heat source 2 heats the air around it, thereby generating warmer and lighter hot air. The hot air thus rises and enters the system 3 as the incoming convective fluid through the inlet of the horizontal portion 311 of the pipe. After passing through the device 32 for heat exchange, the hot air becomes colder and denser cold air. The cold air leaves the device 32 as the outgoing convective fluid and flows towards the vertical portion 312 of the pipe. The cold air can be guided to descend to the outlets 312a, which are located at a level similar to that of the heat source 2. Thus, the pipe can be regarded as supplying cold air and forming a cold air lake near the ground. As the cold air replaces the hot air, the circulation of the convective fluid flow occurs. Due to the buoyancy effect caused by the air density difference, a cooling effect is produced. Therefore, the heat source 2 on the ground may experience cooling.

[0071] Figure 3 Figure 3 shows a perspective view of the device 32 for heat exchange according to an embodiment provided by the present invention, which can be a finned heat transfer coil. The device includes: a plurality of fins 321; and at least one heat transfer coil having a plurality of elongated cross-section tubes 322, wherein the cross-sectional shape has: a substantially rectangular cross-section with rounded edges, or an oval or elliptical cross-section. Figure 3The subsequent description should be read in conjunction with Figures 1 to 2 the description.

[0072] Preferably, the heat transfer coil is used to cool the received convective fluid. Therefore, it can also be referred to as a "cooling coil".

[0073] The heat transfer coil can be configured such that its elongated cross-section tube 322 is one of a single-pass multi-tube structure or a multi-pass single-tube structure.

[0074] The fin 321 is preferably of a generally planar or flat structure. Each fin 321 may include a longitudinal portion, which may correspond to its height axis. Each fin 321 may also include a transverse portion perpendicular to its longitudinal portion, which may correspond to its width axis.

[0075] The elongated cross-section tube 322 is preferably of an elongated structure, which: has a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section. Each elongated cross-section tube 322 may include a longitudinal portion, and the elongated cross-section has a width axis or a major axis. Each elongated cross-section tube 322 may also include a transverse portion perpendicular to its longitudinal portion, and the elongated cross-section has a height axis or a minor axis. The ratio of the major axis to the minor axis of each elongated cross-section tube 322 may be formed to have an aspect ratio of approximately 2:1 to 5:1.

[0076] Specifically, the fin 321 is arranged at a right angle to the elongated cross-section tube 322 (the fin 321 is arranged to be at a right angle to the elongated cross-section tube 322), and each fin has perforations through which the longitudinal portion of the elongated cross-section tube 322 passes.

[0077] Specifically, the fins 321 may be horizontally distributed and are spaced from each other at substantially equal intervals along the longitudinal portion of the elongated cross-section tube 322.

[0078] Specifically, the fins 321 may be oriented along the longitudinal portion of the elongated cross-section tube 322 such that their transverse portions are substantially perpendicular to the longitudinal portion of the elongated cross-section tube 322.

[0079] Specifically, the elongated cross-section tubes 322 are arranged in a single array and are vertically distributed along the height of the fin 321 and are spaced from each other at substantially equal intervals. In context, a "single array" means a linear arrangement of components to form a single column or row. Here, preferably, the elongated cross-section tubes 322 are arranged in a single array such that all of the elongated cross-section tubes 322 substantially receive the conductive fluid in a simultaneous or near-simultaneous manner. Additionally, since the elongated cross-section tubes 322 are arranged in a single array along the height of the fin 321, this arrangement may also be referred to as a "row" arrangement.

[0080] Specifically, coolant should flow inside the elongated cross-section tube 322, and the coolant flows through the entire longitudinal length of the elongated cross-section tube 322. One end of each elongated cross-section tube 322 can receive cold water or room-temperature coolant, while the other end can discharge the heated coolant. For example, the coolant can be water, or any fluid with a large specific heat capacity.

[0081] Specifically, the elongated cross-section tube 322 can be operably configured or installed such that its long axis is at an angle to the convective fluid guided by the fins 321. This angle is hereinafter referred to as the "tilt angle". The tilt angle can be between approximately 0 degrees and 60 degrees, but most preferably between 0 degrees and 30 degrees. Accordingly, the fins 321 have perforations that are consistent with the tilt angle of the elongated cross-section tube 322.

[0082] In another interpretation of the tilt angle, the tilt angle can be defined as the angle formed between the width axis of the fins 321 and the width / long axis of the elongated cross-section tube 322. Similarly, the tilt angle can be between approximately 0 degrees and 60 degrees, but most preferably 0 degrees to 30 degrees. Correspondingly, the fins 321 have perforations that are consistent with the tilt angle of the elongated cross-section tube 322.

[0083] It should be noted that the long axis, width axis, and height axis of the fins 321 and the elongated cross-section tube 322 are only for reference and relative terms, and are not intended to limit the relationship or orientation of the fins 321 and the elongated cross-section tube 322. In addition, the axes of the fins 321 and the elongated cross-section tube 322 can also be represented by any other geometric system, such as the Cartesian coordinate system, etc.

[0084] Specifically, the heat transfer coil with multiple elongated cross-section tubes 322 has a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, which can make the fins 321 shorter in their width, length, and / or height. Therefore, the surface area of the fins 321 may be reduced. Consequently, the viscous force acting on them may be reduced.

[0085] Specifically, compared with a heat transfer coil with multiple tubes having a circular cross-section, the heat transfer coil with multiple elongated cross-section tubes 322 can be more aerodynamically streamlined and generate less air flow resistance. The elongated cross-section tube 322 has a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and is tilted at a tilt angle.

[0086] Specifically, the heat transfer coil has multiple elongated cross-section tubes 322. The elongated cross-section tube 322 has a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and is tilted at a tilt angle, which helps to remove the condensate formed thereon, thereby further reducing the air flow resistance.

[0087] Figure 3 The interaction of the device 32 for heat exchange in the system 3 is further shown.

[0088] A method for heat exchange can now be described. It should be noted that the described method steps should be regarded as non - restrictive, and those skilled in the art can make minor modifications (such as combining, adding, omitting, or swapping) to these steps without substantially deviating from the described content. In addition, all steps or some steps can be carried out simultaneously or non - simultaneously.

[0089] In the first step, the device 32 is configured to have: a plurality of fins 321; and heat transfer coils in the form of a plurality of elongated cross - section tubes 322 arranged in a single array. In addition, pipes are also configured to accommodate the device 32 as described above.

[0090] In the second step, the device 32 is configured such that each elongated cross - section tube 322 of the heat transfer coil has: a generally rectangular cross - section with rounded edges, or an oval or elliptical cross - section.

[0091] In the third step, the elongated cross - section tubes 322 of the heat transfer coil of the device 32 are configured to be oriented at an inclined angle such that their long axes are inclined with respect to the expected direction of the incoming convective fluid flowing through the elongated cross - section tubes 322 of the heat transfer coil. Preferably, the inclined angle is generally between 0 degrees and 30 degrees.

[0092] In the fourth step, the incoming convective fluid in the form of hot air is received from the inlet of the horizontal part 311 of the pipe and is moved towards the device 32.

[0093] In the fifth step, the incoming convective fluid is then guided by the fins 321 of the device 32 and flows through the device 32.

[0094] In the sixth step, the incoming convective fluid flowing through the device 32 is resisted by the elongated cross - section tubes 322. There is coolant flowing in the elongated cross - section tubes 322, which absorbs heat from the incoming convective fluid. Thus, heat exchange occurs between the incoming convective fluid and the coolant flowing in the elongated cross - section tubes 322, and heat is transferred between the incoming convective fluid and the coolant flowing in the elongated cross - section tubes 322. In this way, the coolant becomes heated coolant. The heated coolant can leave the device 32 and thus flow to different devices for heat exchange to dissipate heat.

[0095] In the seventh step, as heat is transferred from the convective fluid to the coolant, condensation occurs within the device 32, and condensates in the form of water droplets are formed on the fins 321 and / or the elongated cross - section tubes 322.

[0096] Since the fin 321 is configured to be perpendicular to the elongated cross-section tube 322, the condensate formed thereon can flow naturally according to gravity and thus drip towards the tray 33.

[0097] Since the elongated cross-section tube 322 is preferably inclined at an (a) inclined angle, the condensate formed thereon can flow along gravity naturally according to the inclined angle of the elongated cross-section tube 322 and thus drip towards the tray 33.

[0098] In this way, heat is transferred from the incoming convective fluid to the coolant, thereby cooling the incoming convective fluid. Therefore, the hot air becomes cold air.

[0099] In the eighth step, the tray 33 collects the condensate dripping from the device 32 in order to transport it away for treatment or reuse.

[0100] Finally, in the ninth step, the cold air leaves the device 32 as the outgoing convective fluid, flows towards the vertical portion 312 of the pipeline, and then descends to the ground to reach the heat source 2.

[0101] Figures 4 to 7 One or more example structures of the device 32 for heat exchange within the system 3 are shown.

[0102] Figure 4 A cross-sectional side view of a part of the system 3 for heat exchange is shown, the system including the device 32 for heat exchange in the first example structure, wherein the elongated cross-section tubes 322 of its heat transfer coil are arranged in a single array, and the elongated cross-section tube has: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and the inclined angle is approximately 0 degrees.

[0103] Figure 5 A cross-sectional side view of a part of the system 3 for heat exchange is shown, the system including the device 32 for heat exchange in the second example structure, wherein the elongated cross-section tubes 322 of its heat transfer coil are arranged in a single array, and the elongated cross-section tube has: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and the inclined angle is approximately 30 degrees.

[0104] Figure 6 A cross-sectional side view of a part of the system 3 for heat exchange is shown, the system including the device 32 for heat exchange in the third example structure, wherein the elongated cross-section tubes 322 of its heat transfer coil are arranged in a single array, and the elongated cross-section tube has: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and the inclined angle is approximately 45 degrees.

[0105] Figure 7A cross-sectional side view of a part of a system 3 for heat exchange is shown, the system including a device 32 for heat exchange in a fourth embodiment structure, wherein the elongated cross-sectional tubes 322 of its heat transfer coil are arranged in a single array, and the elongated cross-sectional tubes have: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and an inclination angle of approximately 60 degrees.

[0106] Hereinafter, the evaluations conducted to verify the performance of the support structure will be described. It should be noted that the parameters defined or determined in these evaluations should not be construed as limiting the scope of the present invention.

[0107] One or more system models were created using commercially available software (such as Ansys Fluent TM ) and numerical analysis was performed. In particular, the creation of each system model was substantially similar to Figure 2 the cross-sectional view of the system 3 for heat exchange shown.

[0108] A total of seven system models were constructed and simulated.

[0109] The system models include a first system model based on Figure 4 the first embodiment structure shown, called "single row flat", a second system model based on Figure 5 the second embodiment structure shown, called "single row flat 30 degrees", a third system model based on Figure 6 the third embodiment structure shown, called "single row flat 45 degrees", and a fourth system model based on Figure 7 the fourth embodiment structure shown, called "single row flat 60 degrees".

[0110] In addition, it includes a fifth model configured with tubes having a single row of circular cross-sections, called "single row circular"; a sixth model configured with tubes having a double row of staggered circular cross-sections, called "double row circular (staggered)"; and a seventh model configured with tubes having a double row of in-line circular cross-sections, called "double row circular (in-line)".

[0111] During the evaluation, the influence of the structure of each system model on its mass flow rate and refrigeration capacity was studied. In addition, its velocity vector and air flow isotherms were also evaluated.

[0112] In particular, in the evaluation, the tubes of the heat transfer coils of the first model, the second model, the third model, and the fourth model were made to have a tube cross-sectional axial length ratio of approximately 3:1.

[0113] In particular, in the evaluation, the fin lengths and tube spacings of all system models were manufactured according to standard heat transfer coil dimensions known in the art.

[0114] In particular, in the evaluation, the heat transfer coils of all system models were manufactured to have the same heat transfer area.

[0115] In particular, in the evaluation, the air temperature received at the simulated flow inlets of the pipes of all system models was kept constant.

[0116] In particular, in the evaluation, the pipes of all system models were manufactured such that the height of the vertical part was approximately 800 mm and the gap was approximately 100 mm.

[0117] In particular, in the evaluation, the pipes of all system models were manufactured to have a flow inlet with a horizontal part width of approximately 100 mm.

[0118] In particular, in the evaluation, the height of the heat transfer coils of all system models could be uniformly manufactured to be approximately 305 mm.

[0119] In particular, in the evaluation, the length of the tubes of the heat transfer coils of all system models was manufactured to be approximately 50 inches (or 127 cm), or the collective length was approximately 50 inches (or 127 cm).

[0120] In particular, in the evaluation, the fin density of all system models was manufactured to be approximately 10 FPI (fins per inch), and the channel gap was approximately 1.27 mm.

[0121] Simulations of the semi-fin channels were carried out for all seven system models, and the results are shown in Table 1 below.

[0122] Based on the results shown in Table 1, a graph of the increment of sensible heat transfer versus the increment of mass flow rate was plotted, as Figure 8 shown.

[0123] It should be noted that the sixth system model was used as a baseline for comparison with all other system models.

[0124]

Table 1

[0125]

[0126] As shown in Table 1, the results indicate that for the system models with flat tubes having a rectangular cross-section and a circular edge (i.e., the first to fourth system models), the first system model has the highest mass flow rate and sensible heat transfer Q a , and the second system model has the second highest mass flow rate and sensible heat transfer Q a .

[0127] As shown in Table 1, the results indicate that compared with the system models with tubes having a multi-array "double row" (i.e., the sixth and seventh system models), the system models with tubes having a single-array "single row" (i.e., the first to fifth system models) have a higher mass flow rate and cooling capacity.

[0128] As shown in Table 1, when comparing the sixth system model with the first system model, the mass flow rate of the first model increased significantly by 36.1% compared to the sixth system model, from 0.061 kg / s to 0.083 kg / s. In addition, the sensible heat transfer Q of the first system model a also increased significantly by 26.1%, from 1044.1 W to 1316.5 W.

[0129] As shown in Table 1, when comparing the sixth system model with the second system model, the mass flow rate of the second model increased significantly by 34.4% compared to the sixth system model, from 0.061 kg / s to 0.082 kg / s. In addition, the sensible heat transfer Q of the second system model a also increased significantly, from 1044.1 W to 1302.9 W.

[0130] Therefore, it is obvious that by configuring the equipment for heat exchange according to the first system model or the second system model, the improvement in its performance is attributed to the following factors, which include: (i) the reduction of viscous forces due to shorter fin length / width / height and reduced row length / width / height; (ii) the more streamlined design of the flat tubes compared to circular tubes.

[0131] As Figure 9 shown, the thermal boundary layers within the fins merge before leaving the narrow fin spacing. This phenomenon means that for all design configurations, the temperature of the rear coil is similar, which can be observed from the average temperature reduction ΔT in Table 1.

[0132] Figures 10 to 16 Isotherm simulations of all seven system models are shown. Different from forced convection with a constant mass flow rate, the mass flow rate of natural convection needs to consider multiple parameters.

[0133] In particular, the mass flow rate caused by the tubes of the heat transfer coil is a balance between: (i) the buoyancy force generated by the temperature difference; and (ii) the viscous force between the fluid-solid interfaces. The buoyancy force generated by the temperature difference can be related to the variation of density with temperature, which can be derived from the momentum equation coupled with the energy equation and the Boussinesq approximation in natural convection.

[0134] As shown in Table 1, when comparing the system models with single-array "single-row" tubes (i.e., the first to fifth system models) with those with multi-array "double-row" tubes (i.e., the sixth and seventh system models), the average temperature reduction ΔT of the former is lower. This is because Figures 10 to 14 As can be seen, there are bypasses at the top and bottom of the tubes of the heat transfer coil.

[0135] However, in the system models with single-array "single-row" tubes (i.e., the first to fifth system models), the average temperature reduction ΔT is not high enough to cause a significant density difference to overcome the additional viscous force caused by the longer flow path in the system models with multi-array "double-row" tubes (i.e., the sixth and seventh system models).

[0136] Therefore, the system models with single-array "single-row" tubes (i.e., the first to fifth system models) will generate a higher mass flow rate. The reduction in its heat transfer area is offset by the higher heat transfer coefficient brought about by the increase in the mass flow rate.

[0137] Figures 17 to 22 Velocity vector simulations of the first to fifth system models are shown, and these system models are all system models with single-array "single-row" tubes.

[0138] As Figures 18 to 22 shown, the first to fourth system models have less resistance to convective fluid flow because they use flat tubes with a rectangular cross-section with rounded edges as the coil, which can achieve a more streamlined air flow compared to tubes with a circular cross-section.

[0139] However, as Figures 18 to 22 shown, as the tilt angle increases, the windward area of the tube also increases, so the resistance to the incoming convective fluid received is also greater. Referring to Table 1, the mass flow rate of the third system model is very close to that of the fifth system model, while the mass flow rate of the fourth system model is lower than that of the fifth system model.

[0140] Although the first system model can produce the best results in the simulation, considering that the heat transfer coil will get wet due to the formation of condensate during the heat transfer process, it is best to introduce a tilt angle. Under these wet conditions, the retention and discharge behavior of the condensate are mainly determined by the forces acting on its body, which include: surface tension; and flow resistance caused by air velocity and gravity. The retention of the condensate will affect the thermohydraulic performance of the heat exchange and the quality of the outflowing convective fluid (cold air) and the comfort inside the structure.

[0141] Therefore, considering the actual situation, the second system model is the most ideal because its tubes have an inclined angle while the performance is close to that of the first system model. This enables the second system model to improve the drainage of condensate because gravity forces the condensate to drip from the tubes due to the introduced inclination. In addition, since the tubes have a generally rectangular cross-section with rounded edges, the condensate can drip smoothly. In addition, better condensate drainage reduces the viscous forces acting on the convective fluid flow and improves its ability to remove latent heat loads, thereby compensating for the effect of reduced heat transfer area.

[0142] Thus, the apparatus of the present invention and its related systems and methods provide substantial improvements in heat exchange for passive displacement cooling, while enabling increased response speed and cooling capacity in a short period of time to cool a room or enclosed environment. The heat transfer coil provided by the present invention has elongated cross-section tubes having: a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section, and configured at an oblique angle to increase mass flow rate, thereby improving response speed and sensible cooling capacity.

[0143] The present invention is further validated in green buildings for performing passive displacement cooling, as the present invention has solved the major obstacles to its widespread application. In addition, the reduced size of the heat transfer coil can reduce the material cost in the construction of green buildings. Therefore, since no mechanical fans are required, passive cooling with zero air distribution energy can be provided for green buildings, thereby saving energy.

[0144] The present disclosure includes the contents described in the attached claims and the contents described in the above description. Although the present invention has been described in its preferred form with a certain degree of detail, it should be understood that the preferred form of the present disclosure is only for example, and various changes can be made to the combination and arrangement of construction details and components without departing from the scope of the present invention.

Claims

1. An apparatus for heat exchange, wherein, Comprising: A plurality of fins; And A heat transfer coil in the form of a plurality of elongated cross-section tubes arranged in a single array; Wherein each fin is vertically arranged along the longitudinal portion of the elongated cross-section tube, guiding the incoming convective fluid to all of the elongated cross-section tubes for heat exchange on the elongated cross-section tubes.

2. The device according to claim 1, wherein Each elongated cross-section tube of the heat transfer coil has a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section.

3. The device according to claim 1 or 2, wherein The elongated cross-section tubes of the heat transfer coil are configured to be installed at an inclined angle such that the long axis of the elongated cross-section tubes is inclined with respect to the direction of the incoming convective fluid flowing through the heat transfer coil.

4. The apparatus according to claim 3, wherein, The range of the inclined angle is approximately 0 degrees to 60 degrees.

5. The device according to any one of the preceding claims, wherein, The aspect ratio of the elongated cross-section tubes of the heat transfer coil ranges from approximately 2:1 to 5:

1.

6. The apparatus according to any one of the preceding claims, wherein, Each fin is formed with a plurality of perforations through which the elongated cross-section tubes of the heating coil pass.

7. A system for heat exchange, wherein, Comprising: A device for heat exchange, the device comprising: A plurality of fins; and A heat transfer coil in the form of a plurality of elongated cross-section tubes arranged in a single array; and A duct for accommodating the device; Wherein the fins of the device are vertically arranged along the longitudinal portion of the elongated cross-section tubes generally perpendicular to each other, guiding the incoming convective fluid to all of the elongated cross-section tubes for heat exchange on the elongated cross-section tubes, and allowing the outgoing convective fluid to flow into the duct.

8. The system according to claim 7, wherein, Each elongated cross-section tube of the heat transfer coil of the device has a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section.

9. The system according to claim 7 or 8, wherein, The elongated cross-section tubes of the heat transfer coil of the device are configured to be installed at an inclined angle such that the long axis of the elongated cross-section tubes is inclined with respect to the direction of the incoming convective fluid flowing through the heat transfer coil.

10. The system according to claim 9, wherein, The range of the inclined angle is approximately 0 degrees to 60 degrees.

11. The system according to any one of claims 7 to 10, wherein The aspect ratio of the elongated cross-section tubes of the heat transfer coil of the device ranges from approximately 2:1 to 5:

1.

12. The system according to any one of claims 7 to 11, wherein The fins of the device are formed with a plurality of perforations through which the elongated cross-section tubes of the heating coil pass.

13. The system according to any one of claims 7 to 12, wherein, The system further includes a tray disposed adjacent to and below the heat transfer coil to collect condensate formed on the device.

14. The system according to any one of claims 7 to 13, wherein, The duct includes a horizontal portion and a vertical portion that are bent at a substantially right angle with respect to each other.

15. The system according to claim 14, wherein The device is located within the horizontal portion of the duct and is adjacent to the vertical portion of the duct.

16. The system according to claim 14 or 15, wherein, The vertical portion of the duct has a horizontal length that extends from the vertical portion to below the horizontal portion.

17. A method for heat exchange, wherein, Comprising: Steps of configuring a device for heat exchange, the device comprising: A plurality of fins; and A heat transfer coil in the form of a plurality of elongated cross-section tubes arranged in a single array; and Steps of configuring a duct for accommodating the device; Wherein the fins of the device are vertically arranged along the longitudinal portion of the elongated cross-section tubes generally perpendicular to each other, guiding the incoming convective fluid to all of the elongated cross-section tubes for heat exchange on the elongated cross-section tubes, and allowing the outgoing convective fluid to flow into the duct.

18. The method according to claim 17, wherein The method further includes the step of configuring each elongated cross-sectional tube of the heat transfer coil of the device to have a generally rectangular cross-section with rounded edges, or an oval or elliptical cross-section.

19. The method according to claim 17 or 18, wherein The method further includes the step of configuring the elongated cross-sectional tubes of the heat transfer coil of the device to be installed at an inclined angle such that the long axis of the elongated cross-sectional tubes is inclined with respect to the direction of the incoming convective fluid flowing through the heat transfer coil.

20. The method according to any one of claims 17 to 19, wherein, The method further includes the step of collecting condensate formed on the device by a tray disposed adjacent and below the device.

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