NL2014599A

NL2014599A - Heat Exchanger.

Info

Publication number: NL2014599A
Application number: NL2014599A
Authority: NL
Inventors: Van Kessel John; Idiyatullina Gulnaz; Hullekes Rien; Kuijt Jan
Original assignee: Van Kessel Beheer B V
Priority date: 2015-04-08
Filing date: 2015-04-08
Publication date: 2016-10-12
Also published as: NL2014599B1

Abstract

The present invention is in the field of a heat exchanger. A heat exchanger is an apparatus for efficient heat transfer from one medium to another, typically from (hot) gas to (cold) water. The media may be fully separated from one and another to prevent mixing, e.g. by a solid wall, or they may be in direct contact. Heat exchangers are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment.

Description

Heat Exchanger

FIELD OF THE INVENTION

The present invention is in the field of a heater exchanger .

BACKGROUND OF THE INVENTION

The present invention is in the field of a heat exchanger. A heat exchanger is an apparatus for efficient heat transfer from one medium to another, typically from (hot) gas to (cold) water. The media may be fully separated from one and another to prevent mixing, e.g. by a solid wall, or they may be in direct contact. Heat exchangers are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. An example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Heat exchanger may have different flow arrangements. In parallel-flow heat exchangers, the two fluids (e.g. air and water) enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow heat exchangers the fluids enter the exchanger from opposite ends. A counter current design is typically more efficient, in that it can transfer the most heat from the heat (transfer) medium per unit mass due to the fact that the average temperature difference along any unit length is higher. In a cross-flow heat exchanger, the fluids travel roughly perpendicular to one another through the exchanger.

Various types of heat exchangers exist, such as a double pipe heat exchanger, a dynamic scraped surface heat exchanger, a shell and tube heat exchanger, a phase-change heat exchanger, a plate heat exchanger, a plate and shell heat exchanger, an adiabatic wheel heat exchanger, a plate fin heat exchanger, a pillow plate heat exchanger, a fluid heat exchanger, a direct contact heat exchanger, and a microchannel heat exchanger.

Prior art heat exchangers suffer from a number of drawbacks. For instance fouling of impurity deposit on a heat exchange surface reduces heat transfer and heat transfer effi- ciency over time. Fouling is amongst others caused by reaction products that occur from metals typically used, such as oxidized products. Also particle deposition is an issue. In addition, also generation of ions and presence of ions causes further problem. Further, due to use of metals, such as stainless steel, but also to some extend when using aluminium, parts of the heat exchanger oxidizes and corrodes, leading to down time, malfunction, and leakage. Also maintenance, especially intermittent maintenance is an issue, in particular for larger installations. Metallic heat exchangers also have limited design freedom, which can cause direct or indirect problems for a design, such as limited heat transfer, vulnerably parts, etc. Metallic heat exchangers are heavy requiring substantial mechanical attachment. And further metallic parts in general generate cross talk and noise.

The present invention therefore relates to an improved heater, which solve one or more of the above problems and drawbacks of the prior art, providing reliable results, without jeopardizing functionality and advantages.

SUMMARY OF THE INVENTION

The present invention relates to a heat exchanger according to claim 1. The present heat exchanger is best compared to a cross-flow heat exchanger, in that gas and water travel largely perpendicular to one and another. The present heat exchanger is preferably a spiral heat exchanger forming at least one fluid flow path, whereas typically the second heat fluid (gas) can flow freely along the at least one fluid flow path. For efficiency, the present heat exchangers are designed to maximize a surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger. The present heat exchange performance may also be improved by addition of fins and corrugations, which increase surface area and may channel fluid flow or induce turbulence.

The present heat exchanger comprises a multitude of passage ways from at least one first material, the passage ways being in fluid connection with one and another, hence forming at least one fluid flow path. In an example the multitude of passage ways relate to a spiral like structure. For providing a fluid an inlet is present, connected to at least one passage way. Also an outlet is present, also connected to at least one passage way. There may be at least one inlet and at least one outlet, e.g. for providing a first and second temperature incoming fluid, and likewise outgoing fluid. The inlet, outlet, and passage ways form at least one fluid flow path for passing through a fluid, the fluid to be heated by e.g. a gas passing by. Further a heat source for heating the fluid is provided; the heat source may be an active source, such as a gas burner, or a passive source, such as a flue gas generated by a burner, worm air leaving a building, etc. It is noted that in principle the present heat exchanger can be used to heat a fluid, wherein heat is supplied by a further fluid, or to cool a fluid, wherein e.g. a colder further fluid is provided. Also a supporting element from at least one second material is provided, wherein the supporting elements supports a multitude of passage ways and allows heat to flow from the heat source to the passage ways. Such a heat exchanger can be found in the prior art. The present heat exchanger is characterized in that the first material used in the multitude of fluid passage ways is selected from a polymer. Such is typically not considered as polymers suffer from various drawbacks, e.g. having a (too) low melting temperature and a too low thermal conductivity. Therefore the present polymer has a melting point and glass transition temperature of above 370 °K, preferably above 450 °K, more preferably above 500 °K, such as above 550 °K. The glass transition temperature can be measured using differential scanning calorimetry (DSC) at a constant cooling rate (20 K/min) and a viscosity threshold of 1012 Pa-s (ISO 11357-2). The present polymer preferably is a thermoset polymer, even more preferably a cross-linked thermoset polymer. The present polymer has a thermal conductivity of > 1 W/mK (at 293 °K), preferably of > 2 W/mK, more preferably of > 5 W/mK, such as of > 10 W/mK. Values of 40 W/mK are achievable with the present polymers. The thermal conductivity can be measured according to ISO 22007-2, using the transient plane source method. The present thermal conductivity is lower than that of e.g. steel or aluminium (which are typically used materials for heat exchangers) and much higher than typical values for polymers (0.02-0.3 W/mK). Polymers are in general considered to be good thermal (and electrical) insulators. A further advantage of the present polymer compared to previously used materials such as metals is the relatively low density of less than 2 g/cm3, preferably less than 1.8 g/cm3, more preferably less than 1.6 g/cm3. For a polymer such as density may be considered still relatively high, but in view of prior art metals (aluminium 2.7-2.8 g/cm3, steel ~7 g/cm3) the present heat exchanger is at least a few kilos lighter, and typically 5-10 kilos lighter; in view of installation such as a big advantage. The polymer is chemically inert; as a result the present heat exchanger needs much less maintenance and has a much longer life time. No corrosion is possible and fouling and the like are reduced or absent. Stress experiments indicate a lifetime of 20-40 years and a scheduled maintenance interval of > 5 years. The present polymer also provides a much higher tensile strength (yield strength). Whereas aluminium and steel have a tensile strength of 100-500 MPa (depending on the exact grade and the like), whereas the present polymer has a tensile strength of > 1.000 MPa, or even > 1800 MPa. Tensile strength for metals can be measured according to ISO 6892-1 and 6892-2, and for the present polymer the same or ISO 37 can be used. It is noted that some very high quality special purpose metals may have comparable tensile strengths, but these are typically not used for heat exchanger, e.g. in view of costs and other (production) drawbacks. As a further advantage effect also the low electrical conductivity (102 —1010 Ω/cm) is mentioned; not only is it found that due to this low conductivity disturbances and antenna effects in e.g. the electrical components in close vicinity of the heat exchanger are virtually absent, but also an active heat source, such as a gas burner, is slightly more efficient (1% relative). The present polymer provides a large design freedom, especially when compared to metallic materials. Examples of these polymers are polypropylene, polyphthalamide, polyamide (6 and 6,6), thermoplastic copolyesters (COPE), polyphenylene sulphide, liquid Crystal Polymer, and thermoplastic elastomer. Examples hereof are CoolPoly® D Series and CoolPoly® E Series, such as D1202, D1802, D3608, D5110, D5112, D5506, E2, E 1202, E3603, E3607, E3610, E3612, E4501, E4505, and E5101.

For the second material a similar polymer may be selected as the first polymer, or a different polymer may be selected. For instance if a high thermal conducting PPS is chosen as a first material, a thermal insulating PPS may be chosen as second material. It is preferred to use a thermal insulating second material. In addition, or as an alternative, a insulating layer or package may be provided around the present heat exchanger.

The present heat exchanger may be made from one piece. It is preferred to produce the present heat exchanger by rotation moulding, using one or more moulds; an example thereof is given in figure 6. In an alternative, such as the examples of figs. 2-5, the sides (walls) are made by injection moulding and the fluid passage ways tubes by extrusion.

Thereby the present invention provides a solution to one or more of the above mentioned problems and drawbacks.

Advantages of the present description are detailed throughout the description.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates in a first aspect to a heat exchanger according to claim 1.

In an example of the present heat exchanger the polymer comprises a homogeneous or heterogeneous aromatic ring, preferably a homogeneous aromatic ring. It has been found that especially aromatic rings provide the above advantageous characteristics .

In an example of the present heat exchanger the polymer comprises a sulphide linkage. An example of such a polymer is poly phenylene sulphide. A commercial example thereof are Celanese CoolPoly® D Series and E-series, and in particular D5101 and E5101.

In an example of the present heat exchanger the polymer comprises 0.01-3 wt% (based on the total weight of the polymer) an additive, the additive being selected from carbon black, ceramics, such as a titanate, a zirconate, graphite, graphene, anthracite, silicon, silicon carbide, tungsten carbide, silicate, non-corrosive metals, and alumina, wherein the additive is preferably present as particles having a diameter of 1-100 nm, more preferably of 2-50 nm. It has been found that especially addition of these types of additives, and carbon black and ceramics in particular, improve thermal properties of the present polymers significantly, from effectively being a thermal insulator to providing thermal conducting properties. The increase is rather remarkable, as comparable polymers have a conductivity of 10-103 times lower.

In an example of the present heat exchanger the heat source is located above or below the passage ways. The heat source can be an active heat source or a passive heat source. In case of an active heat source, such as a gas burner, the heat source is preferably located above the passage ways. In case of an passive heat source, such as a flue gas flow, the heat source is preferably located below the passage ways.

In an example of the present heat exchanger a condensate drain pan or wherein a flue gas connector is provided below the passage ways. Similar to the heat source directly above in combination thereof, or as an add-on, the condensate drain pan or the connector is provided.

In an example of the present heat exchanger the condensate drain pan comprises a sump (37), an inlet (38) and an outlet (31) for gases, in particular combustion gases, as well as an outlet (32) for condensate, characterized in that at least the sump (37)is made of a non-corrodible or corrosion-resistant material.

In an example of the present heat exchanger the supporting element comprises two removable sides, each side providing a multitude of connections for connecting a first passage way to a next passage way further on in the fluid flow path.

In an example of the present heat exchanger the inlet and outlet are comprised in at least one of the two removable sides. Such makes the present heat exchanger easy to install and easy to produce.

In an example of the present heat exchanger the supporting element further comprises a cap, the cap being fixable to the heat source and allowing heat to flow from the heat source to the passage ways.

In an example of the present heat exchanger one side and the passage ways are removable fixed to a remainder of the supporting element.

In an example the present heat exchanger further comprises at least one of a seal, a fan, a mixer, a gas burner, a slide for receiving the passage ways, a burner plate, a housing, a fin, and a burner hood.

In an example of the present heat exchanger the polymer comprises 0.01-2 wt. % biocide, 0.01-2 wt. % fungicide, 0.01-3 wt. % filler, 0.01-2.5 wt. % anti-fouling agent, and 0.01-5 wt. % stabilizer.

The one or more of the above examples and embodiments may be combined, falling within the scope of the invention. EXAMPLES

The below relates to examples, which are not limiting in nature .

The invention is further detailed by the accompanying figures, which are exemplary and explanatory of nature and are not limiting the scope of the invention. To the person skilled in the art it may be clear that many variants, being obvious or not, may be conceivable falling within the scope of protection, defined by the present claims.

FIGURES

The invention although described in detailed explanatory context may be best understood in conjunction with the accompanying figures.

Fig. 1 shows an illustration of a polyphenelyne polymer .

Figs. 2-6 show a present heat exchanger.

Fig. 7 shows a condensate drain pan. DETAILED DESCRIPTION OF THE FIGURES In the figures: 100 Heat exchanger 10 multitude of passage ways 21 inlet 22 outlet 30 condensate drain pan 31 gas outlet 32 condensate outlet 33 inspection port 34 cover 35 heat exchanger 36 support frame 37 sump 38 inlet 40 heat source 41 siphon 50 supporting element 51 removable side 52 removable side 53 cap 62 flue gas connector 81 seal 82 fan 83 a mixer 84 a gas burner 85 a slide for receiving the passage ways 86 a burner plate 87 a housing 88 a burner hood 89 fin 90 central channel

Fig. 1 shows an illustration of a polyphenelyne polymer .

Fig. 2 shows a present heat exchanger 100. Therein at a bottom side a condensate drain pan 30 is provided for collecting and removing condensate. At a left side a side 51 is provided, which may be removable. Also a supporting element 50 is shown, which may be a housing. An outlet 22 is shown for removing warm water. At a top side a cap 53 comprising a heater (not visible) is shown. The cap may comprise or incorporated therein a seal 81, a fan 82 for providing a downward air-flow, a mixer 83 for uniform mixing gases, a gas burner 84 as a heat source, typically a downward gas burner, a slide 85 for receiving the passage ways, a burner plate 86 for receiving heat and regulating heat, a housing 87, and a burner hood 88; these latter items are not shown. A length of this heat exchanger may be from 100-500 mm, a width from 100-500 mm, and a height from 100-500 mm.

Fig. 3 shows a worked open version of the heat ex- changer 100 of fig. 2. In addition an inlet 21 and fluid passageways 10 are shown. In the sides 51,52 connecting parts for the fluid passage ways 10 are visible. In this heat exchanger heat flows from a top side from the heat source 40 located in the cap 53 downwards towards the condensate drain pan 61.

Fig. 4 shows that a multitude of fluid passage ways 10 can be located above and beneath one and another, and left and right of one and another.

Fig. 5 shows a heat exchanger having spiral formed fluid passage ways 10 and a central channel 90 for passing a hot fluid, such as water. In this case the central channel may be the heat source 40.

Fig. 6 shows an alternative lay-out having spiral formed fluid passage ways 10 around a supporting element 50, and in addition fins 89 or the like placed in the heat flow. The supporting element may be made from the same material as the fluid passage ways, as an alternative embodiment.

Fig. 7 shows an example of a condensate drain pan 30. Therein a gas outlet 31, a condensate outlet 32, an inspection port 33, a cover 34, a heat exchanger 35, a support frame 36, a sump 37, an inlet 38, and a siphon 41 are provided. Details of this condensate drain pan are provided in EP 2 602 568 A2.

The figures have been further detailed throughout the description.

Claims

A heat exchanger (100) comprising a plurality of passages (10) from at least one first material, the passages being in fluid communication with each other, an inlet (21) connected to at least one passage, and outlet (22) connected to at least one passage, the inlet, outlet, and passages forming at least one fluid flow tract, a heat source (40) for heating the liquid, a support element (50) of at least one second material, the support element being a plurality of passages supports and allows heat to flow from the heat source to the passages, characterized in that the first material is selected from a polymer, the polymer having a melting point and glass transition temperature of more than 370 ° K, a thermal conductivity of> 1 W / mK ( at 293 ° K), has a density of less than 2 g / cm 3, and the polymer is chemically inert.

The heat exchanger of claim 1, wherein the polymer comprises a homogeneous or heterogeneous aromatic ring.

A heat exchanger according to any one of the preceding claims, wherein the polymer comprises a sulfide bond.

A heat exchanger according to any one of the preceding claims, wherein the polymer comprises 0.01-3% by weight (based on the total weight of the polymer) of an additive, wherein the additive is selected from carbon black, ceramic, such as a titanate, a zirconate, graphite, graphene, anthracite, silicon, silicon carbide, tungsten carbide, silicate, non-corrosive metals, and alumina.

A heat exchanger according to any one of the preceding claims, wherein the heat source is above or below the passages.

A heat exchanger according to any one of the preceding claims, wherein a condensate collection tray (30) or wherein a flue gas connector (62) is provided under the passages.

A heat exchanger according to claim 6, wherein the condensate collection tray comprises a collection tray (37), an inlet (38) and an outlet (31) for gases, in particular combustion gases, and an outlet (32) for condensate, the at least the collection tray (37) is made from a non-corrodible or corrosion-resistant material.

A heat exchanger according to any one of the preceding claims, wherein the support element (50) comprises two removable side partitions (51, 52), each side providing a plurality of connections for connecting a first passage with a next passage further down the fluid flow tract.

The heat exchanger according to claim 8, wherein the inlet and outlet are contained in at least one of the two detachable side partitions.

A heat exchanger according to any one of the preceding claims, wherein the support element further comprises a cap (53), the cap being attachable to the heat source and allowing heat flow from the heat source to the passages.

A heat exchanger according to any of claims 8-10, wherein one side and the passages are removably attached to a remainder of the support element.

A heat exchanger according to any one of the preceding claims, further comprising at least one of a seal (81), a fan (82), a mixer (83), a gas burner (84), a slider for receiving the passages (85 ), a burner plate (86), a housing (87), a burner cap (88), and a fin (89).

A heat exchanger according to any one of the preceding claims, wherein the polymer comprises 0.01-2 wt. % biocide, 0.01-2 wt. % fungicide, 0.01-3 wt. % filler, 0.01-2.5 wt. % anti-fouling agent and 0.01-5 wt. % stabilizer.