CN220771982U - Heat exchanger and fluid flow system for use on the exterior of a building - Google Patents

Abstract

Provided herein is a heat exchanger and a fluid flow system for use on the exterior of a building, the heat exchanger comprising a tubular element extending between a first end and a second end, wherein the tubular element is configured to be inclined relative to a horizontal plane in use such that its second end is raised higher than its first end, the first end being configured to act as a heat source in use, the second end being configured to act as a heat sink in use, wherein the tubular element comprises a fluid inlet for connection to a fluid source, a fluid outlet for connection to a fluid sink, and a capped vent, the fluid inlet and the fluid outlet being arranged at the first end of the tubular element, wherein the fluid inlet extends at least partially axially within the tubular element and is raised higher than the fluid outlet, and the capped vent is arranged at the second end.

Description

Heat exchanger and fluid flow system for use on the exterior of a building

Technical Field

The present utility model relates to a heat exchanger for use on the exterior of a building, preferably a heat exchanger using natural forces such as gravity and capillary forces and renewable energy sources such as solar and wind energy and renewable resources such as rainwater. The utility model also relates to a fluid flow system comprising a heat exchanger, preferably for cooling and heating.

Background

Cooling water and heating water are not only required for direct consumption such as shower or washing, but also for providing space cooling/heating energy for buildings and homes. Furthermore, there is a need for cooling and heating systems that are inexpensive and easy to install and that are quiet and simple to maintain and repair.

Global warming currently presents serious problems to the environment. Fossil fuel use (e.g., for heating and cooling) has greatly led to global warming because fossil fuels release large amounts of carbon dioxide into the atmosphere. The use of refrigerant gases in cooling and heating systems also contributes to global warming because these gases deplete the protective ozone layer in the earth's atmosphere. Therefore, there is a need for a renewable and sustainable solution to heating and cooling.

There are special demands on cooling and heating systems in hot and arid areas. These areas typically experience large diurnal temperature differentials: in summer, the daytime temperature can reach 45C to 50C, while the nighttime temperature is typically between 27C and 30C. Tap water flows through long pipes and absorbs heat during the day due to the pipe being exposed to sunlight. Friction with the inner surface of the pipe also generates additional heat due to the high velocity water flow. In addition, household water is typically stored in roof tanks, which become hotter due to daytime sun exposure. Thus, during the day, the mains supplied water may reach a temperature of 40C or higher, i.e. above body temperature, making it too hot for the shower. Indoor or underground water tanks cannot solve this problem because they cannot benefit from a cooler night time ambient temperature to lower the temperature of the water.

Traditionally, a water tank chiller and cooler are used to obtain cold water for shower and household use. These all have their respective disadvantages. In particular, water tank refrigerators consume a large amount of power and pose a health hazard due to potential mixing of the refrigerant with the water in the tank. The tank cooler may be ineffective and may grow legionella. Furthermore, they are dangerous due to potential electrical shocks. Even when powered by solar energy, the efficiency of refrigerators and coolers is limited by sky conditions, especially cloudy weather.

Other renewable resources suffer from several drawbacks that make them unsuitable for hot and arid areas. For example, geothermal and biomass technologies are associated with environmental pollution, earthquake/deforestation problems, high costs, and restrictions on sites with suitable geothermal/biomass resources.

Disclosure of Invention

According to a first aspect of the present utility model there is provided a heat exchanger for use on the exterior of a building, the heat exchanger comprising a tubular element extending between a first end and a second end, wherein the tubular element is configured to be inclined relative to the horizontal in use such that its second end is elevated above its first end, the first end being configured to act as a heat source in use, the second end being configured to act as a radiator in use, wherein the tubular element comprises a fluid inlet for connection to a fluid source, a fluid outlet for connection to a fluid sink, and a capped vent, the fluid inlet and the fluid outlet being arranged at the first end of the tubular element, wherein the fluid inlet extends at least partially axially within the tubular element and is elevated above the fluid outlet, and the capped vent is arranged at the second end to enable a first fluid flow from the fluid inlet and from the first end to the second end within the tubular element and to enable a second fluid flow from the first end to the second end through a density change so as to flow from the second end to the first end within the tubular element and to the fluid outlet such that the second fluid flow and the second fluid flow directly and counter-flow directly to each other as natural fluid flow.

Mounting the heat exchanger on the exterior of a building (e.g., a building roof) enables cooling of the fluid within the heat exchanger to use renewable resources such as solar and wind energy. The heat exchanger of the present utility model thus provides a cost effective and energy efficient solution that is able to utilize renewable energy sources suitable for hot and arid areas.

The heat exchanger may be configured such that the overall temperature of the first fluid flow is different, preferably higher, than the overall temperature of the second fluid flow in use. Preferably, the first fluid flow is positioned above the second fluid flow. The movement of the first and second fluid streams as counter-streams in direct contact with each other not only enables efficient heat transfer between the two fluid streams via direct heat conduction and natural heat convection, but also facilitates the fluid exiting the heat exchanger as a properly cooled or heated fluid.

The angle of inclination of the heat exchanger relative to the horizontal may be varied as desired.

The heat exchanger may comprise a fluid flow controller configured to control, in use, the flow of the first fluid flow from the fluid inlet and from the first end to the second end within the tubular element, and to control the flow of the second fluid from the first fluid flow to the first end and to the fluid outlet within the tubular element by a change in density. In use, the fluid flow controller may be used for connection between a fluid inlet and a fluid source. Such fluid flow controllers may include, but are not limited to, pumps. This enables the flow of fluid within the heat exchanger to be controlled to optimise heat exchange between the fluid within the heat exchanger and the environment outside the heat exchanger and between the first fluid flow and the second fluid flow within the heat exchanger. Preferably, the first fluid flow and the second fluid flow are controlled to be laminar or substantially laminar.

In embodiments of the utility model, the heat exchanger may comprise a fluid retaining element arranged on, above, below, beside or around the outer surface of the tubular element, wherein the fluid retaining element may be configured to retain fluid in use so as to form a fluid film on, above, below, beside or around the outer surface of the tubular element. The provision of the fluid retaining element enables evaporative cooling to further improve the efficiency of the heat exchanger.

In embodiments of the utility model, the fluid retaining element may comprise a UV resistant material and/or a fluid absorbing material and/or a fabric material. For example, the fluid retaining element may comprise cotton gauze or synthetic cloth, both materials enabling fluid to move through the fluid retaining element by capillary action in order to replace fluid lost by evaporation.

It is contemplated that the fluid retaining element may use different types of fluids to achieve the evaporative cooling effect. The preferred choice of fluid is distilled water. Accordingly, the heat exchanger of the present utility model may include a distilled water source for providing distilled water to the fluid retaining element. Examples of distilled water sources may include, but are not limited to, distillers (e.g., solar distillers) and storage tanks (e.g., outdoor storage tanks), which may, for example, filter and accumulate rain water. In addition, water produced after filtration by mechanical air conditioning and dehumidifiers may be suitable for evaporation.

Different configurations of the tubular element are envisaged.

Preferably, the tubular element is an elongate tubular element.

The tubular member may include a plurality of elongated tubular sub-members. The fluid inlet and fluid outlet may be arranged at the first end of the tubular element to enable, in use, a first fluid flow to flow within the elongate tubular sub-element from the first end to the second end and a second fluid flow to flow within the elongate tubular sub-element from the second end to the first end such that the first fluid flow and the second fluid flow move as counter-flows in direct contact with each other.

Different arrangements of a plurality of elongated tubular sub-elements are envisaged. The plurality of elongated tubular sub-elements may be spaced apart from one another. A plurality of elongate tubular sub-elements may be arranged to extend parallel to each other between the first and second ends of the tubular element.

The provision of a plurality of elongate tubular sub-elements not only increases the heat exchanger surface area available for heat exchange, but also allows wind to efficiently blow dust away from the outer surface of the elongate tubular sub-elements.

Further, the tubular element may comprise a first tubular connector fluidly interconnecting the elongated tubular sub-elements at or towards the first end of the tubular element and a second tubular connector fluidly interconnecting the elongated tubular sub-elements at or towards the second end of the tubular element. This not only simplifies the design of the flow of fluid into and out of the elongated tubular sub-element, but also makes it easier to operate and install the heat exchanger.

According to a second aspect of the present utility model there is provided a heat exchanger for use on the exterior of a building, the heat exchanger comprising a tubular element extending between a first end and a second end, wherein the tubular element is configured to be inclined in use relative to a horizontal plane such that its second end is raised higher than its first end, wherein the first end is configured to be inclined in use relative to a horizontal plane between two corners of the tubular element, wherein the second end is configured to be inclined in use relative to a horizontal plane between two other corners of the tubular element, wherein the tubular element comprises a fluid inlet for connection to a fluid source, a fluid outlet for connection to a fluid sink, and a capped vent, the fluid inlet and the fluid outlet being arranged in the tubular element to enable fluid flow within the tubular element between the first end and the second end in use.

The above-described construction of the heat exchanger enhances cooling of the fluid within the heat exchanger by locating one corner of the tubular element lower than the other corners of the tubular element. In particular, in such a configuration, the inclination of the tubular elements is such that the direction of one or more fluid flows in the tubular elements is not perpendicular to the direction of the surrounding air (e.g. due to natural convection or intermittent wind energy). This effectively creates a semi-cross flow between the one or more fluid streams and the ambient air, which enhances cooling of the fluid within the heat exchanger.

The fluid inlet and fluid outlet may be arranged at the first end of the tubular element to enable a fluid flow to flow within the tubular element between the first end and the second end in use.

In embodiments of the utility model, the fluid inlet and the fluid outlet may be located at or towards the lowest one of the corners of the tubular element.

In further embodiments of the utility model, the capped vent may be located at the highest one of the corners of the tubular element.

The heat exchanger may comprise a single tubular element. The heat exchanger may comprise a plurality of tubular elements. Providing a plurality of tubular elements increases the surface area for heat exchange. At least two of the plurality of tubular elements may be configured to share a common fluid inlet and/or a common fluid outlet and/or a common capped vent.

In an embodiment of the utility model, the first end may be configured to be inclined with respect to a horizontal plane between two corners of the tubular element in use, wherein the second end may be configured to be inclined with respect to a horizontal plane between two other corners of the tubular element in use.

It will be appreciated that features of the heat exchanger of any of the first aspect of the utility model and embodiments thereof may be combined with features of the heat exchanger of any of the second aspect of the utility model and embodiments thereof.

In an embodiment of the utility model, the tubular element may comprise a fluid distribution conduit and a tubular conduit, the fluid distribution conduit being connected to the fluid inlet, wherein the fluid distribution conduit may comprise a transfer conduit for transferring fluid from the fluid distribution conduit to the tubular conduit, wherein the transfer conduit may be axially aligned with the tubular conduit and may be arranged to pass through the tubular conduit such that, in use, fluid flows directly from the fluid inlet into the tubular conduit.

The ends of the transfer duct may be formed with inclined fluid dividing walls that extend into the fluid distribution duct.

The tubular element of the present utility model is preferably shaped as a hexagon, preferably an elongated hexagon.

According to a third aspect of the present utility model there is provided a fluid flow system comprising a heat exchanger according to any of the preceding aspects of the present utility model and embodiments thereof, a fluid source and a fluid sink, wherein the fluid inlet of the heat exchanger is connected to the fluid source and the fluid outlet of the heat exchanger is connected to the fluid sink.

The features and advantages of the heat exchanger of the first or second aspect of the utility model and embodiments thereof are applicable mutatis mutandis to the fluid flow system of the third aspect of the utility model and embodiments thereof.

In an embodiment of the utility model, the fluid flow system may comprise a fluid reservoir. The fluid reservoir may be connected to the fluid inlet such that, in use, at least part of the first fluid flow may flow from the fluid reservoir into the heat exchanger via the fluid inlet, and/or wherein the fluid reservoir may be connected to the fluid outlet such that, in use, at least part of the second fluid flow may flow from the heat exchanger into the fluid reservoir via the fluid outlet. This enables the fluid to circulate directly in the circuit between the heat exchanger and the fluid reservoir so that the fluid from the fluid reservoir can be cooled within the heat exchanger before being returned to the fluid reservoir.

In other embodiments of the utility model, the fluid flow system may comprise a fluid reservoir and a first internal heat exchanger extending within and through the fluid reservoir, the first internal heat exchanger being configured such that, in use, fluid within the first internal heat exchanger is physically separable from fluid within the fluid reservoir. The first internal heat exchanger may be connected to the fluid inlet such that, in use, at least part of the first fluid flow may flow from the first internal heat exchanger into the heat exchanger via the fluid inlet, and/or wherein the first internal heat exchanger may be connected to the fluid outlet such that, in use, at least part of the second fluid flow may flow from the heat exchanger into the first internal heat exchanger via the fluid outlet. This enables the fluid to circulate directly in the circuit between the heat exchanger and the first internal heat exchanger such that the fluid from the first internal heat exchanger may be cooled within the heat exchanger before being returned to the first internal heat exchanger, wherein heat may be exchanged between the fluid reservoir and the fluid within the first internal heat exchanger. Thus, heat exchange is achieved between the heat exchanger and the fluid reservoir via the first internal heat exchanger. Further, the fluid reservoir and the first internal heat exchanger may be configured to use different types of fluids. The fluid dispensing device may be connected to the outlet of the fluid reservoir for direct consumption, whereby fluid withdrawn from the reservoir is replaced by fluid entering the reservoir through its inlet.

In a still further embodiment of the utility model, the fluid flow system may comprise a fluid circulation conduit connected to the heat exchanger such that in use fluid may circulate in the circuit through the heat exchanger and the fluid circulation conduit. The fluid circulation conduit may form part of an internal heating and/or cooling system of the building, such as a radiant floor pipe or pipe loop.

The fluid flow system of the present utility model may comprise a second internal heat exchanger extending within and through the tubular element (such as a second tubular connector), the second internal heat exchanger being configured such that, in use, fluid within the second internal heat exchanger is physically separable from fluid within the tubular element (such as the second tubular connector). The provision of the second internal heat exchanger enables heat exchange between the heat exchanger and the fluid within the second internal heat exchanger. In turn, the cooling fluid within the second internal heat exchanger may be fed into an external device. For example, the fluid flow system may comprise a solar collector device, wherein the second internal heat exchanger may be configured to feed fluid to an inlet of at least one fluid tube of the solar collector device in use. This allows the heat exchanger to help heat the fluid within the solar collector apparatus, thereby improving efficiency.

It should be understood that the use of the terms "first," "second," "third," "fourth," etc. in this specification are merely intended to aid in distinguishing between similar features and not to indicate the relative importance of one feature with respect to another unless otherwise indicated.

Within the scope of the present application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs and claims and/or in the following description and drawings, and in particular the various features thereof, may be employed independently or in any combination. That is, all embodiments and all features of any embodiment may be combined in any manner and/or combination unless such features are incompatible. The applicant reserves the right to alter the rights of any original application or apply for any new claim accordingly, including the right to be able to amend any claim attached to any original application and/or incorporate any feature of any other claim (although not originally claimed in the manner described).

Drawings

Preferred embodiments of the present utility model will now be described, by way of non-limiting example, with reference to the accompanying drawings, in which:

FIG. 1 illustrates a single tubular element of a heat exchanger according to an embodiment of the present utility model;

FIG. 2 illustrates a heat exchanger according to an embodiment of the utility model;

FIG. 3 illustrates a fluid distribution conduit;

FIG. 4 shows a heat exchanger according to another embodiment of the utility model;

FIGS. 5-7 illustrate a system for wetting the tubular element of FIG. 1;

fig. 8 shows an evaporative cooling process; and

fig. 9 to 13 illustrate a fluid flow system according to an embodiment of the present utility model.

Detailed Description

The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

Fig. 1 illustrates an external heat exchanger according to an embodiment of the present utility model and is generally indicated by reference numeral 30. The heat exchanger 30 comprises a tubular element capable of carrying a fluid therein. The tubular element extends between a first end 32 and a second end 34 and is mounted inclined with respect to the horizontal so that its second end 34 is raised higher than its first end 32. The tubular member includes a fluid inlet 36 and a fluid outlet 38 formed at the first end 32 of the tubular member. In use, the fluid inlet 36 is fluidly connected to a fluid source, and the fluid outlet 38 is fluidly connected to a fluid sink.

As shown in fig. 2, the tubular element may include a plurality of elongated tubular conduits 40 and first and second tubular connectors 42, 44. The elongate tubular conduits 40 are spaced apart from one another and are arranged to extend parallel to one another between the first and second ends 32, 34 of the tubular member. The first tubular connector 42 extends perpendicular to the elongate tubular conduit 40 and fluidly interconnects the elongate tubular conduit 40 at the first end 32 of the tubular member. The second tubular connector 44 extends perpendicular to the elongate tubular conduit 40 and fluidly interconnects the elongate tubular conduit 40 at the second end 34 of the tubular member.

As schematically shown in fig. 1, when the heat exchanger 30 is used for water cooling, a first fluid stream 46 comprising hot water flows into the heat exchanger 30 through the fluid inlet 36 at the first end 32 of the tubular member and through the elongated tubular conduit 40 from the first end 32 to the second end 34 of the tubular member. While the hot water exchanges heat with the external environment through the walls of the heat exchanger 30, thereby reducing the water temperature of the first fluid stream. The second fluid flow 48 is formed at the first end 32 to the second end 34 of the tubular member and immediately separated from the first fluid flow 46. The second fluid flow 48 exits as cooling water through the fluid outlet 38 at the first end 32 of the tubular member.

Thus, the first fluid flow 46 and the second fluid flow 48 move within the elongated tubular conduit 40 as counter-flows in direct contact with each other, wherein the first fluid flow 46 is above the second fluid flow 48, and wherein the overall temperature of the first fluid flow 46 is higher than the overall temperature of the second fluid flow 48. This is made possible by the oblique orientation of the tubular element in combination with the arrangement of the fluid inlet 36 and the fluid outlet 38 at the first end 32 of the tubular element. The configuration of the first fluid stream 46 and the second fluid stream 48 as countercurrent streams in direct contact with each other enables efficient heat transfer between the first fluid stream 46 and the second fluid stream 68 by direct conduction and thus further enhances the efficiency of the water cooling process.

Preferably, the flow rates of the two fluid streams 46, 48 are low enough to maintain laminar flow, thereby minimizing mixing between the two fluid streams 46, 48. Because the overall temperature of the second fluid stream 48 is lower than the overall temperature of the first fluid stream 46, the cooler second fluid stream 48 has a higher density than the first fluid stream 46. Thus, the flow of the second fluid 48 within the elongated tubular conduit 40 is aided by natural convection.

More specifically, the formation of the first fluid flow 46 and the second fluid flow 48 as countercurrent flows inside the heat exchanger 30 is a natural circulation caused by the density variation and the oblique orientation of the tubular elements under the following conditions:

a. A temperature difference exists between the heat source and the radiator;

b. the heat source is at a lower elevation than the heat sink;

c. the hot and cold streams must be in contact with each other.

The external heat exchanger 30 of the present utility model satisfies these conditions, wherein the first end 32 is lower than the second end 34, the first end 32 acts as a heat source when in use, the second end 34 acts as a heat sink when in use (preferably at ambient temperature), the first fluid stream 46 enters the first end 32 and moves naturally toward the second end 34, and the second fluid stream 48 is naturally formed by a density change caused by a temperature differential. Thus, the first fluid flow 46 and the second fluid flow 48 can move inside the heat exchanger 30 as counter-flows in direct contact with each other.

As shown in fig. 3, the tubular member includes a fluid distribution conduit 50 at a first end thereof. The fluid distribution conduit 50 is connected to the first tubular connector 42 via a series of transfer conduits 52 such that water in the fluid distribution conduit 50 may be diverted into the first tubular connector 42 via the series of transfer conduits 52. Each transfer conduit 52 is axially aligned with a respective one of the elongated tubular conduits 40 and is arranged through the first tubular connector 42 such that water flows directly from the transfer conduit 52 into the elongated tubular conduit 40 and such that the first fluid flow 46 and the second fluid flow 48 are prevented from being completely mixed. Preferably, as shown in FIG. 3, one end of each transfer conduit 52 is formed with an inclined water dividing wall 54 extending into the fluid distribution conduit 50, wherein the water dividing wall 54 acts as a barrier to the flow of water within the fluid distribution conduit 50, thereby redirecting water into each elongated tubular conduit 40 at equal or substantially equal volumetric flow rates.

The fluid inlet 36 is formed in the fluid distribution conduit 50. The fluid outlet 38 is formed on the first tubular connector 42. Thus, water first enters the fluid distribution conduit 50 via the fluid inlet 36, then flows through the elongated tubular conduit 40 as the first and second fluid streams 46, 48, and finally exits the first tubular connector 42 via the fluid outlet 38. Preferably, the fluid inlet 36 is positioned higher than the fluid outlet 38.

The tubular element is made of a thermally conductive material such as aluminum or copper. The length of each tube 40 may be 200cm. The combined elongated tubular conduits 40 may have a width of 100cm, including the spacing between the elongated tubular conduits 40. The diameter of each elongated tubular conduit 40 may be in the range of 5cm to 6.25 cm. The size of the spacing between adjacent elongated tubular conduits 40 may be in the range of 6.25cm to 10 cm. The diameter of each tubular connector 42, 44 may be in the range of 6.25cm to 7.5 cm. Preferably, the diameter of each tubular connector 42, 44 is greater than the diameter of each elongated tubular conduit 40.

As part of the fluid flow system, the heat exchanger coil 56 may be arranged to extend within and through the second tubular connector 44. The heat exchanger coil 56 is configured such that, in use, water within the heat exchanger coil 56 may be physically separated from water within the second tubular connector 44. In this way, the heat exchanger coil 56 and the second tubular connector 44 form a shell and tube heat exchanger that allows heat to be transferred from the water within the second tubular connector 44 to the water within the heat exchanger coil 56. The heated water within the heat exchanger coil 56 may be fed to an external device 58, such as a vacuum tube solar collector.

In other embodiments of the utility model, the tubular elements may be further tilted such that the first tubular connector 42 is tilted with respect to a horizontal plane between two corners of the tubular elements and the second tubular connector 44 is tilted with respect to a horizontal plane between the other two corners of the tubular elements. In this way, one corner of the tubular element is lower than the other corners of the tubular element. As a result, the direction of the fluid flow or flows in the tubular element is not perpendicular to the direction of the surrounding air (such as due to natural convection or intermittent wind energy). This effectively creates a semi-cross flow between the one or more fluid streams and the ambient air, thereby enhancing the cooling of the fluid within the heat exchanger 30.

In an alternative embodiment, schematically illustrated in fig. 4, the heat exchanger 30 comprises two tubular elements fluidly interconnected with each other, wherein the tubular elements are arranged side by side. Each of the tubular elements of fig. 4 is similar in structure and function to the tubular element of fig. 1 except that the tubular elements share a common fluid inlet 36, a common fluid outlet 38, and a common capped vent 64.

Preferably, each tubular element is inclined such that one corner of the tubular element is lower than the other corners of the tubular element. In such embodiments, the common fluid inlet 36 and the common fluid outlet 38 may be disposed at or toward the lowest corner of each tubular element. The first and second tubular connectors 42, 44 and the fluid distribution conduit 50 may be formed in a V-shape. The fluid outlet 38 is preferably formed at or towards the base 60 of the V-shaped first tubular connector 42. The fluid inlet 36 is preferably formed at or toward the base 62 of the V-shaped fluid distribution conduit 50.

Optionally, in various embodiments, a covered vent 64 for venting heat exchanger 30 may be located in second tubular connector 44 (such as shown in fig. 1 and 2, and such as the apex of V-shaped second tubular connector 44). The covered vent 64 may include a valve operable to allow air bubbles to escape and prevent dust from entering. The capped vent allows the pressure levels of the first fluid stream 46 and the second fluid stream 48 to be balanced by exposing the first fluid stream 46 and the second fluid stream 48 to atmospheric pressure. This increases the laminar flow of the fluid streams 46, 48 and reduces turbulence, thereby promoting separation between the fluid streams 46, 48 to prevent mixing.

As shown in fig. 4, a support bracket 66 may be provided to stably hold the heat exchanger 30 to which the first and second tubular connectors 42 and 44 are connected.

The tubular element is preferably shaped as a hexagon, and more preferably an elongate hexagon.

A fluid retaining element in the form of cotton gauze 68 is tightly wrapped around the elongated tubular conduit 40 (fig. 5). By stretching the cotton gauze 68, its orifice becomes finer, so that capillary action increases. The purpose of the cotton gauze 68 is to retain moisture so as to form a film of water around the outer surface of the elongated tubular conduit 40.

Distilled water is supplied from a distilled water source to cotton gauze 68. This in turn causes cotton gauze 68 to form a film of distilled water around the elongated tubular conduit by adhesion, gravity and diffusion. Other types of fluid absorbent fabric materials may be used in place of cotton gauze 68.

The cotton gauze 68 has a high capillary action which allows distilled water to flow from the elongated tubular conduit 40 to the remainder of the cotton gauze 68. Furthermore, the mesh structure of the cotton gauze 68 helps to form a large film of distilled water on the outer surface of the elongated tubular conduit 40 while providing a reduced surface contact area relative to its surrounding environment, thereby advantageously reducing dust deposition. Even if dust deposits are to be formed on the cotton gauze 68, the cotton gauze 68 can be easily sun-dried and blown clean by wind. As a result, the cotton gauze 68 is less prone to dust deposition, which can limit the evaporative cooling effect. In addition, the flexibility of the cotton gauze 68 and the tight wrapping of the cotton gauze 68 around the elongated tubular conduit 40 enables the cotton gauze 68 to withstand strong winds.

Fig. 5 shows a capillary tube 70 at the upper end of the elongated tubular conduit 40. The capillary tube 70 supplies distilled water to the elongated tubular conduit 40 at or near the second end 34 of the tubular member. Mao Xisheng 71 is threaded axially through each capillary 70 at one end and is in contact with cotton gauze at the other end. The inner diameter of each capillary 70 may be precisely or about 2mm. Preferably, mao Xisheng is made of cotton or synthetic fiber yarns.

Fig. 6 shows a series of capillaries 70, each of which is used to supply distilled water onto a respective elongated tubular conduit 40 at or near the second end 34 of the tubular member. The capillary tube 70 is connected to a common fluid conduit 72 located above the tubular member second end 34. The common fluid conduit 72 may be connected to a distilled water source, which may be a small horizontal cylindrical tank 74 (or other storage tank), and the small horizontal cylindrical tank 74 may be supplied with distilled water from a storage tank 76, wherein the supply of water is controlled by a pump 78, which in turn is controlled by a controller 150 (as schematically shown in fig. 7). The capillaries 70 are connected and spaced apart along the length of the common fluid conduit 72 between the first and second ends. By capillary force, a relatively equal amount of distilled water flows out of the capillary tube 70. Fig. 6 shows a series of capillaries 70 connected to a V-shaped conduit, but other shapes of conduit are contemplated.

Distilled water continuously flows through and across capillary tube 70 because distilled water is free of salts that may clog capillary tube 70.

Preferably, the capillary tube 70 and the common fluid conduit 72 are made of a co-extruded cross-linked polyethylene composite ("pex-al-pex") material.

Fig. 8 shows an evaporative cooling process performed using the heat exchanger 30. Since the ambient temperature around the heat exchanger 30 is lower than the hot water temperature of the first fluid stream 46 within the elongated tubular conduit 40, heat from the hot water is transferred to the ambient environment through the walls of the elongated tubular conduit 40. A thin film of distilled water on the outer surface of the elongated tubular conduit 40 enhances heat transfer by evaporative cooling.

When the thin film of distilled water absorbs thermal energy from the hot water within the elongated tubular conduit 40 by conduction and from ambient heat by convection, evaporation of water molecules occurs. Thus, a wet heat layer 80 is formed around the elongated tubular conduit 40, and the wet layer 80 moves upward by natural convection, leaving a volume of low pressure air around the elongated tubular conduit. The volume of low pressure air is then replaced with a volume of high pressure air 82 from the surrounding environment. Thus, heat is removed from the hot water within the elongated tubular conduit and dispersed into the environment while cold dry air flows to the elongated tubular conduit to continue the evaporative cooling process. The evaporative cooling process may also be enhanced by intermittent wind 84, especially during the night.

In an exemplary scenario, within a few hours after the sunset, the surrounding environment near the heat exchanger 30 is heated by the release of solar radiation absorbed by the underlying surface during the day. This may cause the outer surface of the heat exchanger 30 to dry by convection and radiation, thereby increasing the consumption of distilled water. The evaporation process is delayed for several hours after sunset, for example, for about three hours after sunset at 7 pm, thus reducing the consumption of distilled water. Thus, the evaporative cooling process is most effective during the night, from about 10 pm to about 7 am the next day. The temperature around the heat exchanger 30 reaches the night wet bulb temperature, which may be in the range of 14 to 16 ℃. Accordingly, the temperature of the water in the heat exchanger 30 is reduced to about 6 to 7 ℃ higher than the wet bulb temperature, i.e., in the range of 20 to 23 ℃. Since the sun rises very long in the summer, it is preferable to shield the heat exchanger from direct sunlight from sunrise time until the end of the evaporative cooling process at about 7 a.m. so that the evaporative cooling process can benefit from cold and dry morning air. Although evaporative cooling may be slow, or may provide a relatively low amount of cooling at any given time, the overnight duration of the evaporative cooling process is sufficient to provide the desired overall cooling.

As shown in fig. 8, experiments performed by the present inventors showed that heat exchanger 30 cooled the water in the cold water storage tank by as much as 15-16 ℃ compared to the water in a control cold water storage tank cooled only by 1.5-1.65 ℃ without heat exchanger 30.

The heat exchanger 30 may be placed on a flat rack on a roof of a sloping building or may be placed on a sloping rack on a roof of a sloping building. Alternatively, the heat exchanger 30 may be placed on the ground instead of on a roof.

An insulating material is located between the support and the heat exchanger 30. The minimum height of the stand is high enough, preferably 80cm, to not only protect the heat exchanger 30 from radiation due to heat absorbed by the surface under the heat exchanger 30 during the day, but also to enable easy installation and removal of the cotton gauze 68 depending on cooling and heating requirements.

The longitudinal slope ratio (also referred to as the slope) of the elongated tubular conduit 40 is selected to enhance fluid flow within the heat exchanger 30 by natural convection, and it also aids in the gravity flow of distilled water onto the elongated tubular conduit 40. Preferably, the longitudinal inclination ratio of the elongated tubular conduit 40 is exactly or about 15:100.

The ratio of lateral inclination of the elongated tubular conduit 40 is selected to allow hot water to flow easily upward toward the capped vent to allow bubbles to escape, to assist the movement of the second fluid flow 48 toward the fluid outlet 38, and to increase the surface area of the heat exchanger 30 exposed to the wind to enhance the evaporative cooling process. Preferably, the transverse inclination ratio of the elongated tubular conduit 40 is exactly or about 4:100.

Fig. 9-13 illustrate fluid flow systems that may be used for water cooling and heating applications. Illustratively, the fluid flow system is used to cool water in summer and to heat water in other seasons. The system is particularly suitable for individual households in hot areas and arid areas.

In fig. 9, 10 and 11, the fluid flow system includes a heat exchanger 30 and a fluid circulation conduit 86 that may be used in combination in a closed loop water cooling application such that, in use, fluid may be circulated in the circuit through the heat exchanger 30 and the fluid circulation conduit 86. The heat exchanger 30 is preferably mounted on the roof of a building, as the wind flow is not impeded by walls and trees, but may be mounted on the ground in other embodiments.

As shown in fig. 10, a fluid flow controller in the form of a pump 88 (e.g., a low flow pump) is optionally connected between the fluid circulation conduit 86 and the fluid inlet 36 of the heat exchanger 30. In use, the pump 88 is operable to control the flow rate of hot water from the fluid circulation conduit 86 to the heat exchanger 30, thereby enabling laminar flow of the first fluid stream 46 and the second fluid stream 48 within the heat exchanger 30. The fluid outlet 38 is connected to the fluid circulation conduit 86 to return cooling water from the heat exchanger 30 to the fluid circulation conduit 86, which may be by gravity and/or pumping. In this way, water circulates between the heat exchanger 30 and the fluid circulation conduit 86.

The fluid circulation conduit includes a radiant floor piping loop 90 that extends through a floor 92 of the building, which may be a concrete slab. Water is pumped through the radiant floor piping loop 90. Preferably, a low flow pump is used. The cooling water flowing through the radiant floor piping loop 90 is used to cool the space inside the building by absorbing heat. The warmed water flowing through the radiant floor piping loop 90 is then returned to the heat exchanger 30. The temperature of the cold water is typically around 20C, which is a comfortable temperature for the cooling chamber. At the same time, the temperature of the cold water is high enough to prevent condensation on the floor, especially in arid areas where the air humidity is low. The radiant floor piping loop 90 provides a large surface area, thus enhancing heat exchange and thus cooling. The cooling effect can be further enhanced by using ceiling fans and the likelihood of floor condensation is reduced.

As shown in fig. 11, during the day (e.g., from 7 a.m. to 7 a.m.), the flow of water into and out of the heat exchanger 30 may cease.

As shown in fig. 10, the covered vent 64 in the second tubular connector 44 is optionally connected to a drain return tank 94 that allows water to drain from the heat exchanger 30 into the drain return tank 94 in order to protect the heat exchanger from freezing during severe cold conditions. The drain-back tank 94 is preferably installed inside the building.

When the ambient temperature reaches the freezing point, an ambient temperature sensor 96 installed outside the building sends a signal to the controller 200. The controller 200 in turn sends a signal to open the valve 98 placed between the fluid circulation conduit 86 and the drain-back tank 94. When the ambient temperature rises above freezing, the drain-back tank 94 is drained by closing the valve 98 and turning on the pump 100 to refill the heat exchanger 30 through the connection tube 102. The connection pipes 102, 104 are substantially parallel and extend upwardly from the drain-back tank 94. The drain water return tank 94 may also be used to empty the heat exchanger 30 during periodic maintenance. When the drain-back tank 94 is used as a solar collector during colder seasons, it also allows repositioning of the heat exchanger 30 towards sunlight.

Alternatively, the fluid flow system may include a heat exchanger 30 and a cold water storage tank that may be used in combination in a closed loop water cooling application. The cold water storage tank is preferably installed inside a building. The cold water tank is exemplarily made of an aluminium sheet or a sheet lined with a plastic layer or an aluminium plastic tube material, and is preferably closed by an insulating material. The aluminum plate or sheet is strong enough to withstand a constant and relatively low ram pressure. The water in the cold water storage tank is preferably treated water.

Such fluid flow systems may include an internal heat exchanger that extends within and through the cold water storage tank. The warm water enters the internal heat exchanger via a warm water feed pipe and is cooled via heat exchange with cold water in the cold water storage tank as it flows through the internal heat exchanger. The cooled water flows out of the internal heat exchanger and can then be used for home use or consumption.

In an alternative configuration of the fluid flow system shown in fig. 12, a fluid circulation conduit in the form of an internal heat exchanger 86 may extend within and through the cold water storage tank 106, with a pump 88 for controlling the circulation of water between the heat exchanger 30 and the internal heat exchanger 86. The water in the internal heat exchanger 86 is physically separated from the water in the cold water storage tank 106. Heat exchange occurs between the water in the internal heat exchanger 86 and the water in the cold water storage tank 106. The pump 88 transfers hot water from the internal heat exchanger 86 to the fluid inlet 36 of the heat exchanger 30, and cooling water is returned from the heat exchanger 30 to the internal heat exchanger 86. In this way, water circulates between the heat exchanger 30 and the internal heat exchanger 86.

As shown in fig. 13, pump 88 may be omitted from the alternative configuration of the fluid flow system shown in fig. 12.

As previously described, the heated water within the heat exchanger coil 56 may be fed to an external device. The heated water within the heat exchanger coil 56 is fed into the inlet of the fluid tube of the evacuated tube solar collector 58. The water in the fluid tube is then further heated by operation of the vacuum tube solar collector 58. In this way, the heat exchanger 30 can help heat the water by means of the vacuum tube solar collector 58. In such use, the fluid retaining element is removed from the heat exchanger 30 to allow exposure to sunlight, as evaporative cooling is not required.

Preferably, such heat helps occur during cold periods and/or by tilting the heat exchanger 30 toward the sun. The heat exchanger 30 may be blackened to improve the absorption of solar thermal energy. A sheet metal deck may be added to the underside of the heat exchanger 30 to increase the efficiency of its reflection back to unscattered solar radiation.

The fluid flowing through the fluid flow system is typically treated water, distilled water, rain water and air. The fluid bearing components (such as the conduits and pipes) are preferably made of pex-al-pex material, which has many advantages such as inhibiting algae growth and resisting bad weather. The Pex-al-Pex material is non-reactive and thus suitable for all types of flowing fluids and is also easy to install. For optimum efficiency, the fluid carrying components of the fluid flow system should be thermally insulated.

Since the evaporative cooling process occurs at night and thus there is no sunlight, algae growth on the heat exchanger 30 is eliminated. Furthermore, during the day, the temperature of the heat exchanger 30 rises to 60C due to sun exposure, and at night it drops to a night wet bulb temperature, which is approximately or in the range of 15C to 16C. This broad temperature range prevents microorganisms from growing on the heat exchanger 30. Furthermore, the intermittent wind interacting with the heat exchanger 30 impedes the stable conditions required for algae growth. It also accelerates the drying of the cotton gauze 68, further disrupting the conditions required for algae growth.

Corrosion of the inner walls of the pipe in the fluid flow system is prevented due to the relatively low temperatures in both cooling and heating configurations. Specifically, in the portion of the fluid flow system carrying the cooling water, the maximum temperature of the circulating water does not exceed 50C. Although the temperature of the water within the heat exchanger 30 may rise to about 60C during the daytime in summer, the water is not flowing because the cooling system is not running. In the part of the fluid flow system carrying hot water, the maximum temperature of the circulating water does not exceed 60C. In addition, the flow rate of the circulated treated water is low, for example, about 2 liters per minute. In addition, since the water has been treated, it does not corrode aluminum, which is the preferred material for the heat exchanger 30, heat exchanger coil 56 and internal heat exchanger.

If the amount of stormwater kept each year is sufficient to provide the amount of water needed for evaporative cooling, the kept stormwater may be suitable for use as distilled water for evaporative cooling. Filtration may be used to remove leaves, large particles and/or suspended solid particles from the stored stormwater. A cartridge filter may be provided to filter light/small particles in the stormwater before it enters the small horizontal cylindrical tank 74.

When the heat exchanger 30 is used as a passive water cooler that benefits from night time cooling, the entire distilled water assembly may be removed, or the supply of distilled water to the elongated tubular conduit 40 may be stopped. This is because the need for a thin film of distilled water is eliminated for evaporative cooling. The cold water produced may be suitable for showering because the temperature of the cooled water is lower than the temperature of the human body. The cooling process is described as follows: tap water enters the cold water reservoir 106. When the sun is lifted, the pump 88 between the internal heat exchanger 86 and the fluid inlet 36 of the heat exchanger 30 is turned off. During the day, the water within the heat exchanger 30 heats up. After a period of time (e.g., 3 hours) from sunset, the cooling process begins when the pump 88 is turned on to circulate water between the heat exchanger 30 and the internal heat exchanger 86.

Advantages of the present utility model include, but are not limited to: effective water cooling and proper heating; the cost is low and the initial installation is simple; easy maintenance and access; the risk of Legionella is avoided; almost no sound pollution; durable; weather resistance; minimal or no moving parts; reducing the need for environmentally hazardous fossil fuels and refrigerant gases; and reduces the electricity charge. In particular, the heat exchanger 30 of the present utility model is more cost effective than conventional heat exchangers because:

a) It saves time. The temperature difference between the heat exchanger 30 and the surrounding environment is greater, thus enabling the excess heat to be extracted more quickly. In addition, the hot water traverses a shorter distance through the first end 32 than through the second end 34 and thus takes less time to reach the heat exchanger 30, and

b) It is more efficient because the evaporative cooling process uses a thin film of water around the tubular duct 40, which is not applicable to conventional heat exchangers. In particular, the cooled distilled water flows from the second end 34 to the first end 32 in indirect contact with the first fluid stream 46 flowing from the first end 32 to the second end 34. The heat exchange by countercurrent flow is more efficient than the heat exchange by flat flow, which can be used in conventional heat exchangers.

Heat exchangers and fluid flow systems according to embodiments of the utility model may scale building size and/or building heating or cooling requirements.

The listing or discussion of a clearly-prior-published document or clearly-prior-published information in this specification is not necessarily to be taken as an acknowledgement that the document or information is part of the state of the art or is common general knowledge.

Preferences and options for a given aspect, feature or parameter of the utility model should be considered as having been disclosed in connection with any and all preferences and options for all other aspects, features and parameters of the utility model, unless the context indicates otherwise.

Claims (10)

1. A heat exchanger for use on the exterior of a building, the heat exchanger comprising a tubular element extending between a first end and a second end, wherein the tubular element is configured to be inclined in use relative to a horizontal plane such that its second end is raised higher than its first end, wherein the first end is configured to be inclined in use relative to a horizontal plane between two corners of the tubular element, wherein the second end is configured to be inclined in use relative to a horizontal plane between two other corners of the tubular element, wherein the tubular element comprises a fluid inlet for connection to a fluid source, a fluid outlet for connection to a fluid sink, and a capped vent, the fluid inlet and the fluid outlet being arranged in the tubular element to enable fluid flow within the tubular element between the first end and the second end.

2. A heat exchanger for use on the exterior of a building according to claim 1, wherein the fluid inlet and the fluid outlet are located at or towards a lowest one of the corners of the tubular element, and/or wherein the capped vent is located at or towards a highest one of the corners of the tubular element.

3. A heat exchanger for use on the exterior of a building, the heat exchanger comprising a tubular element extending between a first end and a second end, characterised in that the tubular element is configured to be inclined in use relative to a horizontal plane such that its second end is raised higher than its first end, the first end being configured to act as a heat source in use, the second end being configured to act as a radiator in use, wherein the tubular element comprises a fluid inlet for connection to a fluid source, a fluid outlet for connection to a fluid sink, and a capped vent, the fluid inlet and the fluid outlet being arranged at the first end of the tubular element, wherein the fluid inlet extends at least partially axially within the tubular element and is raised higher than the fluid outlet, and the capped is arranged at the second end to enable a first fluid flow from the fluid inlet to flow from the first end to the second end in use and to enable a second fluid flow from the first end to the tubular element to flow from the second end as a natural flow from the first fluid inlet to the second end and vice versa.

4. A heat exchanger for use on the exterior of a building according to claim 1 or claim 3, wherein the tubular element comprises a fluid distribution conduit connected to the fluid inlet and a tubular conduit, wherein the fluid distribution conduit comprises a transfer conduit for transferring fluid from the fluid distribution conduit to the tubular conduit, wherein the transfer conduit is axially aligned with the tubular conduit and arranged to pass through the tubular conduit such that, in use, fluid flows directly from the fluid inlet into the tubular conduit.

5. A heat exchanger for use on the exterior of a building according to claim 4, wherein the ends of the transfer ducts are formed with inclined fluid dividing walls extending into the fluid distribution ducts.

6. A heat exchanger for use on the exterior of a building according to claim 1 or claim 3, wherein the tubular elements are shaped as elongate hexagons.

7. A heat exchanger for use on the exterior of a building according to claim 1 or claim 3, comprising a fluid retaining element arranged on, above, below, beside or around the outer surface of the tubular element, wherein the fluid retaining element is configured to retain fluid in use so as to form a fluid film on, above, below, beside or around the outer surface of the tubular element.

8. A fluid flow system comprising a heat exchanger according to claim 1 or claim 3, a fluid source and a fluid sink, wherein the fluid inlet of the heat exchanger is connected to the fluid source and the fluid outlet of the heat exchanger is connected to the fluid sink.

9. The fluid flow system of claim 8, wherein the fluid flow system comprises:

a. a fluid reservoir, wherein the fluid reservoir is connected to the fluid inlet such that, in use, at least a portion of a first fluid flow is able to flow from the fluid reservoir into the heat exchanger via the fluid inlet, and/or wherein the fluid reservoir is connected to the fluid outlet such that, in use, at least a portion of a second fluid flow is able to flow from the heat exchanger into the fluid reservoir via the fluid outlet; or alternatively

b. A fluid reservoir and a first internal heat exchanger extending within the fluid reservoir and passing through the fluid reservoir, the first internal heat exchanger being configured such that, in use, fluid within the first internal heat exchanger is physically separable from fluid within the fluid reservoir, wherein the first internal heat exchanger is connected to the fluid inlet such that, in use, at least a portion of a first fluid flow is able to flow from the first internal heat exchanger into the heat exchanger via the fluid inlet, and/or wherein the first internal heat exchanger is connected to the fluid outlet such that, in use, at least a portion of a second fluid flow is able to flow from the heat exchanger into the first internal heat exchanger via the fluid outlet.

10. The fluid flow system of claim 8, comprising a second internal heat exchanger, wherein the second internal heat exchanger extends within and through the tubular element, the second internal heat exchanger configured such that, in use, fluid within the second internal heat exchanger is physically separable from fluid within the tubular element.