WO2025056158A1

WO2025056158A1 - An electrical fluid heater

Info

Publication number: WO2025056158A1
Application number: PCT/EP2023/075205
Authority: WO
Inventors: Pierre-Louis GAS; Ales Ruzicka; Serif KARAASLAN; Laurent Decool
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2023-09-14
Filing date: 2023-09-14
Publication date: 2025-03-20
Anticipated expiration: 2026-03-14

Abstract

An electrical fluid heater (100) includes a heating elements (10), end parts (20), cover parts (30), an inlet (32) and an outlet (34). The heating elements (10) are supported between the end parts (20). The plurality of cover parts (30) in conjunction with the end parts (20) define an enclosure for enclosing the heating elements (10) and fluid flow passages around the heating elements (10). The inlet (32) and the outlet (34) is for ingress and egress of the fluid with respect to the enclosure. The electric fluid heater (100) further includes inter-connected turbulators (40). The turbulators (40) are disposed in free space around the heating elements (10). Each turbulator (40) includes a main intermittent channel (42) and at least one side intermittent channel (44) abutting and in fluid communication with the main intermittent channel (42). The side intermittent channels (44) permit fluid communication between the main intermittent channels (42).

Description

AN ELECTRICAL FLUID HEATER

FIELD

The present invention relates to a heat exchanger, particularly, to tabulators for an electric fluid heater for a vehicle.

BACKGROUND

A vehicle generally includes a heater for heating air to be supplied to a passenger compartment. Alternatively, the heater supplies heated air to demist or defrost the windscreen. In some cases, the heater is used to supply hot air or hot coolant for cold starting the engine. With the emergence of the electric vehicles and hybrid vehicles, the heater is also applicable for battery thermal management. The heaters can be used for efficient thermal management of the batteries used for powering the electric motor, thereby drastically enhancing the service life of the batteries. The air to be heated is generally passed through a heat exchanger, which includes heating element in the form of an electrical resistive element supplied with current in case of an electrical resistive heater. Particularly, the air to be heated circulates across the heating element of the heat exchanger and extracts heat from the heating element.

The conventional electrical fluid heater 1 , for example, electric fluid heater 1 disclosed in the US Published Patent application US20130186966A1 includes a plurality of heating elements 2, particularly, resistive heating elements 2, a pair of side parts 3, cover parts 4, an inlet and an outlet. The heating elements 2 are supported between end plates 3. The cover parts 4 in conjunction with the end parts 3 define an enclosure for enclosing the heating elements 2 and defining fluid flow path around the heating elements. Generally, a system pump directs the coolant to the electrical fluid heater 1. The inlet and the outlet is for ingress and egress of the fluid with respect to the enclosure. Generally, the fluid entering inside enclosure through the inlet escapes through outlet without sufficient heat exchange with the heat elements 2. More specifically, the fluid entering inside the enclosure quickly flows through the small gaps around the heating elements without undergoing sufficient heat exchange with the heating elements 2. Further, the fluid flow around the heating elements is laminar, thereby substantially reducing the heat transfer between the heating elements 2 and the fluid flowing around the heating element 2. Further, the fluid entering inside the enclosure is non-uniformly distributed along the surface of the heating elements, thereby resulting in many problems such as the hot spots resulting in thermal stresses and mechanical failures of the heating elements 2. Further, the efficiency and performance of the conventional electrical fluid heater is substantially reduced due to non-uniform distribution of the fluid along the surface of the heating elements 2, thereby either requiring more number of heating elements or large heating elements to achieve specific heating capacity, causing increase in overall cost and also making the electrical fluid heater bulky .

To address the above problems, the prior art suggests arranging the turbulators 6 around the heating elements. Although, such arrangement is aimed at converting flow of fluid around the heating elements from laminar flow to turbulent flow, retarding the fluid flow around the heating elements, uniformly distributing the fluid along the surface of the heating elements to enhance heat exchange between the heating elements and the fluid flowing there-around. However, the electric fluid heaters configured with conventional turbulators 6 face several problems. For example, the electric fluid heater configured with convention turbulators cause huge pressure drop there across, thereby requiring larger high power pumps, thereby increasing the overall costs. Specifically, the electrical fluid heater configured with conventional turbulators 6 fail to strike a balance between high heat transfer rate and low pressure drop across the electric fluid heater. Further, the electric fluid heaters configured with conventional turbulators 6 fail to uniformly distribute the fluid along the surface of the heating elements. Furthermore, the manufacturing of the conventional turbulators and securing of the turbulators to the heating elements is complex and prone to defects.

Accordingly, there is a need for an electrical fluid heater that obviates the problems such as hot spots due to non-uniform distribution of fluid along the surface of the heating elements faced by electric fluid heater configured with conventional turbulators. Further, there is need for an electric fluid heater that achieves high heat transfer rates without incurring high-pressure drop across the electrical fluid heater. Furthermore, there is a need for an electrical fluid heater configured with turbulators that exhibits higher surface rated power, thereby requiring fewer heating elements and accordingly can be packaged in limited space in vehicle environment. Still further, there is a need for an electrical fluid heater configured with turbulators that can operate using comparatively smaller, low powered system pump, fewer and /or smaller heating elements compared to system pumps required for conventional electrical fluid heaters with same rated power, accordingly are comparatively inexpensive and compact than the electrical fluid heater configured with conventional turbulators.

An object of the present invention is to provide an electric fluid heater that achieves high heat transfer rates without incurring high-pressure drop across the electrical fluid heater.

Another object of the present invention is to provide an electric fluid heater that achieves uniform distribution of fluid along the surface of the heating elements.

Yet another object of the present invention is to provide an electric fluid heater that exhibits enhanced thermal efficiency and performance.

Still another object of the present invention is to provide an electrical fluid heater that is reliable and exhibits improved service life.

Another object of the present invention is to provide an electrical fluid heater configured with turbulators that exhibits higher surface rated power, thereby requiring fewer and/or smaller heating elements compared to conventional electrical fluid heaters of same rated power and accordingly are inexpensive and compact to be able to packaged in limited space in vehicle environment.

Yet another object of the present invention is to provide an electrical fluid heater configured with turbulators that can operate using smaller, low powered, system pump and accordingly are comparatively inexpensive than the electrical fluid heater configured with conventional turbulators. In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.

SUMMARY

An electrical fluid heater is disclosed in accordance with an embodiment of the present invention. The electrical fluid heater includes a plurality of heating elements, end parts, a plurality of cover parts, an inlet and an outlet. The plurality of heating elements are supported between end parts. The plurality of cover parts in conjunction with the end parts define an enclosure for enclosing the heating elements and fluid flow passages around the heating elements. The inlet and the outlet is for ingress and egress of the fluid with respect to the enclosure. The electric fluid heater further includes inter-connected turbulators. The turbulators are disposed in free space around the heating elements. Each turbulator includes a main intermittent channel and at least one side intermittent channel abutting and in fluid communication with the main intermittent channel. The side intermittent channels permit fluid communication between the main intermittent channels.

Generally, the turbulators are either uniformly or non-uniformly spaced with respect to each other

Specifically, the turbulators are separated by a flat intermediate portion disposed between the adjacent turbulators.

In accordance with an embodiment of the present invention, the turbulators are formed by either one of stamping and calendering operation on a metal blank.

Particularly, the flat intermediate portion between adjacent turbulators is secured to flat surfaces of the heating element by a joining process. Preferably, the main intermittent channel is sandwiched between the side intermittent channels.

Generally, the side intermittent channels formed on opposite sides of the main intermittent channel are arranged in staggered manner with respect to each.

Particularly, each of the main intermittent channels and the side intermittent channel is of rectangular cross section.

More specifically, cross section of the main intermittent channel is same as the cross section of the side intermittent channel.

Specifically, first open-ends of the main intermittent channels and the side intermittent channels respectively are proximal to and facing the inlet.

More specifically, at least one of the first open-ends of the main intermittent channels and the side intermittent channels respectively are aligned with the inlet.

Further, the side intermittent channels permit fluid communication between the main intermittent channels.

Generally, the main intermittent channel is extending parallel to the lateral side of the corresponding heating element.

Particularly, the main intermittent channel includes uniformly spaced main cutouts formed on opposite lateral sides thereof common with the respective side intermittent channels. Further, the side intermittent channels are in fluid communication with the main intermittent channel through the main cut-outs.

Generally, the side intermittent channels include spaced apart side cutouts respectively extending along orthogonal sides thereof and disposed between the adjacent main cutouts formed on the main intermittent channel.

More specifically, the main intermittent channels are in fluid communication with each other through the first and second side-cutouts formed on the side intermittent channels respectively.

BRIEF DESCRIPTION

Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:

FIG. 1 illustrates a sectional view of a conventional electrical fluid heater configured with conventional turbulators, also is illustrated an enlarged view of the conventional turbulators disposed adjacent to heating elements of the electrical fluid heater;

FIG. 2 illustrates an isometric view of an electrical fluid heater in accordance with an embodiment of the present invention;

FIG. 3 illustrates an exploded view of the electrical fluid heater of FIG.2; FIG. 4 illustrates a top view of the electrical fluid heater FIG. 2 and

FIG. 5 illustrates a sectional view of the electrical fluid heater along section line A- A of FIG.4.

FIG. 6 illustrates an isometric sectional view of the electrical fluid heater of FIG. 4;

FIG. 7 illustrates an isometric view of the electrical fluid heater of FIG. 6 without one cover part to depict internal details thereof, also is illustrated an enlarged view of the turbulators;

FIG. 8 illustrates an isometric view of the turbulators; and

FIG. 9 illustrates a front view of the turbulators.

DETAILED DESCRIPTION

The present invention envisages an electrical fluid heater that includes heating elements supported between end plates and arranged inside an enclosure formed by assembling cover plates. The electrical fluid heater of the present invention includes turbulators disposed around heating elements to achieve turbulent flow, uniform distribution of fluid, improved contact and heat transfer between the heating elements and fluid flowing around the heating elements. The present invention is explained in the forthcoming description and accompanying drawings with example of electric fluid heater, particularly, a high voltage coolant heater used in vehicular environment. However, the present invention is also applicable in applications, where high heat transfer with minimum pressure drop across the electric fluid heater is required, and where, it is required to achieve high rated power using fewer heating elements and comparatively smaller sized pump to achieve compact configuration for being able to be packaged in a limited space.

FIG. 2 illustrates an isometric view of an electrical fluid heater 100 disclosed in accordance with an embodiment of the present invention. FIG. 2 illustrates an isometric view of an electrical fluid heater 100. FIG. 3 illustrates an exploded view of the electrical fluid heater 100. FIG. 4 illustrates a top view of the electrical fluid heater 100. The electrical fluid heater 100 includes a plurality of heating elements 10, end parts 20, preferably end plates 20 and hereinafter referred to as end plates 20, a plurality of cover parts 30, preferably cover plates 30, hereinafter referred to as cover plates 30, an inlet 32 and an outlet 34.

The heating elements 10 are generally electrical heating elements. However, the present invention is not limited to electrical heating elements only but is also applicable to tubular heating elements through which hot fluid flows for the heating purpose. The heating elements 10 are disposed along longitudinal sides of the cover plates 30. Each heating element 10 includes a tube 12 that in turn receives an electrical core 14 therein. Specifically, the tube 12 together with the electrical core 14 forms the heating element 10. The electrical core 14 for example comprises PTC (Positive Temperature Coefficient) resistors. Each tube 12 may have several electrical cores, which may be arranged one after the other in a direction of the tube 12. Each heating element 10 includes electrodes 14a on at least one side of the at least one electrical core 14 for power supply through the heating element 12. The electrodes 14a and electrical cores 14 are the heat generation portions of the heating elements 10. Further, the heating elements 1 include electrically insulating and thermally conductive material layers 16. The layers 16 being disposed in annular space between one of the electrodes 14a and walls of the tube 12. With such configuration of the heating element 10, the tube 12 is electrically insulated from the electrodes 14a and the electrical core 14 but thermally in contact with them. Particularly, with such configuration of the heating element 10, the heat generated in the electrodes 14a and electrical cores 14 is transmitted to the tube 12 whereas the tube 12 is still electrically insulated from the electrodes 14a and electrical cores 14. The heating elements 10 are disposed between and supported by the end plates 20. The end plates 20 includes aligned slots 22 to receive the corresponding heating elements 10. The number of slots formed on the end plates 20 is based on the number of the heating elements supported between the end plates 20.

The cover plates 30 in conjunction with the end plates 20 define an enclosure for enclosing the heating elements 10 and defining fluid flow passages around the heating elements. Instead of four cover plates 30, two side parts of L-section can be assembled to define the enclosure and flow passages around the heating elements 10. Particularly, the present invention is not limited to any particular configuration of the end plates 20 and the cover plates 30 as long as the end plates 20 and the cover plates 30 can be assembled to define a modular construction of a housing for enclosing the heating elements 10 and defining fluid flow passages around the heating elements 10.The ingress and egress of the fluid inside the enclosure formed by the assembly of the cover parts 30 and the end plates 20 is through the inlet 32 and the outlet 34 respectively formed on the cover plates 30. The inlet 32 and the out 34 can be formed on any side of the enclosure formed by assembling the cover plates 30. The present invention is not limited to any particular configuration and placement of the inlet and outlet 32 and 34 respectively, as far as the inlet 32 and the outlet 34 are sufficiently spaced to ensure fluid flow along the heating elements 10 of the electrical fluid heater 100. More specifically, the fluid entering inside the enclosure flows through the gaps between adjacent heating elements 10 and annular spacing between the heating elements 10 and the cover plates 30. Generally, the cover plates 30 are formed L-shaped and are assembled together to form the enclosure with rectangular cross section. Such modular configuration of the enclosure provides convenient access to the components held inside the enclosure for service and maintenance thereof.

The electrical fluid heater 100 of the present invention is configured with turbulators 40 disposed in free space around the heating elements 10. FIG. 5 illustrates a sectional view of the electrical fluid heater 100 along section line A-A depicted in FIG. 4. FIG. 6 illustrates an isometric sectional view of the electrical fluid heater 100. FIG. 7 illustrates an isometric view of the electrical fluid heater 100 without one cover plate 30 to depict internal details thereof, also is illustrated an enlarged view of the turbulators 40. Particularly, the turbulators 40 are disposed between adjacent heating elements 10 and annular space between the heating elements 10 and the cover plates 30. The turbulators 40 convert fluid flow around the heating elements 10 from laminar flow to turbulent flow. Further, the turbulators 40 retard the fluid flow around the heating elements and uniformly distribute the fluid along the surface of the heating elements to enhance heat exchange between the heating elements and the fluid flowing there-around. The electric fluid heater 100 of the present invention is configured with turbulators 40 of unique configuration that achieve uniform flow distribution along the surface of the heating elements 10 for improved heat transfer between the heating elements 10 and the fluid flowing around the heating elements 10 without incurring high-pressure drop across the electrical fluid heater 100.

Particularly, the turbulators 40 disposed in free space around the heating elements 10 are interconnected to each other. More specifically, the turbulators 40 are formed by forming a single metal blank by either stamping or calendering process. The turbulators 40 are spaced form each other with a flat intermediate portion 46 disposed between and separating the adjacent turbulators 40. Generally, either one of stamping and calendering operation on a metal blank forms the turbulators 40. The turbulators 40 are secured to the heating elements 10 by joining process such as for example brazing or welding. Although, in the forthcoming description, the connection between the components of the electrical fluid heater 100 of the present invention, particularly, the connection between the turbulators 40 and the heating elements 10 is explained with example of brazing. However, the connection between various components of the battery cooler of the present invention is not limited to brazing connection and the components of the electrical fluid heater 100, particularly, the connection between the turbulators 40 and the heating elements 10 can also be formed by other joining means such as for example, laser welding. More specifically, the flat intermediate portion between the adjacent turbulators 40 is secured to flat surfaces of the heating elements 10 by brazing process. The turbulators 40 are generally uniformly spaced with respect to each other. The turbulator 40 can be non-uniformly spaced with respect to each other. The spacing between the turbulators 40 is based on requirement, for example, the turbulators 40 near the inlet 32 can be closely packed to improve sideways flow of the fluid. More specifically, the number, spacing and orientation of turbulators 40 can be changed to regulate the fluid flow in the fluid flow passages in the electrical fluid heater 100. However, the present invention is not limited to any particular alignment, placement and spacing between the turbulators 40 as far as the turbulators 40 ensure sideways flow to achieve uniform distribution and sufficient contact between the heating elements 10 and fluid flowing around the heating elements 40.

Each turbulator 40 includes a main intermittent channel 42 and at least one side intermittent channel 44, 46 abutting and in fluid communication with the main intermittent channel 42. Preferably, there are two side intermittent channels 44 and 46 disposed along opposite sides of the main intermittent channel 42. The side intermittent channels 44 and 46 permit fluid communication between the main intermittent channels 42, thereby enhancing the sideways flow with respect to the heating elements to improve surface contact of the fluid with the heating elements 10.

FIG. 8 illustrates an isometric view of the turbulators 40. FIG. 9 illustrates a side view of the turbulators 40. Referring to FIG. 7, FIG. 8 and FIG. 9, the main intermittent channel 42 includes side-walls connected by a connecting wall to define a first open end 42a and a second open end 42b for ingress and egress of fluid with respect to the main intermittent channel 42. The main intermittent channel 42 is having one of the side-walls thereof common with the side intermittent channels 44 and 46 respectively. The main intermittent channel 42 includes uniformly spaced main cutouts 42c formed on opposite lateral sides thereof that are common with the side intermittent channels 44 and 46 respectively. Also the number, spacing and orientation of the main cutouts 42c can be changed to regulate side flow of the fluid and to regulate the fluid flow in the fluid flow passages in the electrical fluid heater 100 for achieving uniform flow distribution. The main intermittent channel 42 is extending parallel to the lateral side of the corresponding heating element 10. In accordance with another embodiment, the main intermittent channel 42 is extending angularly with respect to the lateral side of the corresponding heating element 10.

Similarly, the side intermittent channel 44, 46 also includes side walls connected by a connecting wall to define first open-ends 44a and 46a of the side intermittent channels 44 and 46 respectively. The side intermittent channel 44, 46 includes spaced apart side cutouts 44c, 46c extending along orthogonal sides thereof and disposed between the adjacent main cutouts 42c formed on the main intermittent channel 42. The side intermittent channels 44 and 46 are in fluid communication with the main intermittent channel 42 through the main cut-outs 42c. The side intermittent channels 44 permit fluid communication between the main intermittent channels 42 along the sideways directions depicted by arrows B in the FIG. 7. Specifically, the main intermittent channels 42 are in fluid communication with each other through the first and second side-cutouts 44c and 46c formed on the side intermittent channels 44 and 46 respectively. The configuration of the turbulators 40 is described in details in the forthcoming section of the description. The side intermittent channels 44, 46 permit side flow of fluid with respect to the heating elements 10 to achieve uniform fluid distribution along the surface of the heating elements 10. Such configuration of the turbulators 40 enhances the contact between the heating elements 10 and the fluid around the heating elements 10. Further such configuration of the turbulators 40 ensures uniform distribution of the fluid over an entire surface of the heating element 10, preventing formation of hot spots and increasing the service life and reliability of the electrical fluid heater. Accordingly, the efficiency and performance of the electrical fluid heater 100 is enhanced.

Generally, the main intermittent channel 42 is sandwiched between the side intermittent channels 44. Specifically, the side intermittent channels 44 formed on opposite sides of the main intermittent channel 42 are arranged in staggered manner with respect to each. More specifically, the first side intermittent channel 44 includes first side - cutouts 44c and the second side intermittent channel 46 includes second side-cutouts 46c, wherein at one of the first side-cutouts 44c formed on the first side intermittent channel 44 is disposed between adjacent second side-cutouts 46c on the second side intermittent channel 46. Similarly, at least one of the second side-cutouts 46c on the second side intermittent channel 46 is disposed between adjacent first side-cutouts 44c on the first side intermittent channel 46. Also, the number, spacing and orientation of first side-cutouts 44c and the second side-cutouts 46c can be changed to regulate fluid flow between adjacent turbulators 40 and to regulate the fluid flow in the fluid flow passages in the electrical fluid heater 100 for achieving uniform flow distribution. The main intermittent channels 42 are in fluid communication with each other through the first and second side-cutouts 44c and 46c formed on the side intermittent channels 44 and 46 respectively. Such configuration allows sideways movement of the fluid as the adjacent main intermittent channels 42 are in fluid communication with each other via the corresponding side intermittent channels 44 and 46. With such configuration, the fluid not only flows through the main channel 42 along the length of the main channel 42 as depicted by arrow A in the FIG. 7 but also flows side-ways across the length of the main channel 42 as depicted by arrows B in the FIG. 7.

Further, each of the main intermittent channels 42 and the side intermittent channel 44 is of rectangular cross section. Further, the cross section of the main intermittent channel 42 is same as the cross section of the side intermittent channel 44. Such configuration of the tubulators 40 with intermittent channels of rectangular cross section not only improves fluid flow while limiting the pressure drop across the electrical fluid heater 100 but also provides several other advantages. For example, the turbulators 40 with the main intermittent channel 42 and the side intermittent channels 44 and 46 of rectangular cross section are convenient to be formed compared to intermittent channels with complex sections. More specifically, the rectangular cross section of the intermittent channels enables easy withdrawn of the stamping die from the metal blank after the stamping operation. The rectangular cross section of the intermittent channels further provides sufficient intermediate portions 48 between the adjacent turbulators 40, thereby providing sufficient surface contact between the intermediate portions 48 between the adjacent tabulators 40 and the heating elements 10 to form secure connection therebetween. Also, the rectangular cross section of the turbulators ensure reduced cross section of the turbulators at fluid entry, thereby reducing the system backpressure, at the expense of a slight decrease in heat transfer. The first open-ends 42a of the main intermittent channels 42 are proximal to and facing the inlet 32. Similarly, the first openends 44a and 46a of the side intermittent channels 44 and 46 are also proximal to and facing the inlet 32. Further, the first open-ends 42a of at least one of the main intermittent channels 42 is aligned with the inlet 32. Similarly the first open ends 44a and 46a of at least one of the side intermittent channels 44 and 46 respectively are aligned with the inlet 32. Such rectangular cross section of the main intermittent channels 42 and the side intermittent channels 44 and 46 and the first open ends 42a of the main intermittent channels 42 and the first open ends 44a and 46a of the side intermittent channels 44 and 46 facing the inlet 32 of the electrical fluid heater reduces the blocking encountered by the fluid entering the enclosure due to reduced cross section of the turbulators facing the fluid entrance. Accordingly, the electrical fluid heater 100 requires comparatively smaller and lower powered pump compared to pumps required for conventional electrical fluid heaters of same rated power. In any case, the invention cannot and should not be limited to the embodiments specifically described in this document, as other embodiments might exist. The invention shall spread to any equivalent means and any technically operating combination of means.

Claims

CLAIMS:

1 . An electrical fluid heater (100) comprising:

• a plurality of heating elements (10) supported between end parts (20);

• a plurality of cover parts (30) in conjunction with the end parts (20) defining an enclosure for enclosing the heating elements (10) and fluid flow passages around the heating elements (10);

• an inlet (32) and an outlet (34) for ingress and egress of the fluid with respect to the enclosure, characterized in that the electric fluid heater (100) further comprises inter-connected turbulators (40) disposed in free space around the heating elements, each turbulator (40) comprises a main intermittent channel (42) and at least one side intermittent channel (44, 46) abutting and in fluid communication with the main intermittent channel (42), the side intermittent channels (44, 46) permit fluid communication between the main intermittent channels (42).

2. The electrical fluid heater (100) as claimed in the previous claim, wherein the turbulators are either uniformly spaced or non-uniformly spaced with respect to each other.

3. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein the turbulators (40) are separated by a flat intermediate portion disposed between the adjacent turbulators (40).

4. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein the turbulators are formed by either one of stamping and calendering operation on a metal blank.

5. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein the flat intermediate portion between the adjacent turbulators (40) is secured to flat surfaces of the heating element (10) by joining process.

6. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein the main intermittent channel (42) is sandwiched between the side intermittent channels (44) and (46).

7. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein the side intermittent channels (44) and (46) formed on opposite sides of the main intermittent channel are arranged in staggered manner with respect to each

8. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein each of the main intermittent channels (42) and the side intermittent channel (44, 46) is of rectangular cross section.

9. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein cross section of the main intermittent channel (42) is same as the cross section of the side intermittent channel (44, 46).

10. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein first open-ends (42a) and (44a, 46a) of the main intermittent channels (42) and the side intermittent channels (44, 46) respectively are proximal to and facing the inlet (32).

11. The electrical fluid heater (100) as claimed in the previous claim, wherein at least one of the first open-ends (42a) and (44a, 46a) of the main intermittent channels (42) and the side intermittent channels (44, 46) respectively are aligned with the inlet (32).

12. The electrical fluid heater (100) as claimed in any of the preceding claims, wherein the main intermittent channel (42) is extending parallel to the lateral side of the corresponding heating element (10).

13. The electrical fluid heater (100) as claimed in the preceding claims, wherein the main intermittent channel (42) comprises uniformly spaced main cutouts (42c) formed on opposite lateral sides thereof common with the side intermittent channels (44) and (46) respectively.

14. The electrical fluid heater (100) as claimed in previous claim, wherein the side intermittent channels (44) and (46) are in fluid communication with the main intermittent channel (42) through the main cut-outs (42c).

15. The electrical fluid heater (100) as claimed in the claim 13, wherein the side intermittent channel (44) and (46) comprises spaced apart first and second sidecutouts (44c) and (46c) respectively extending along orthogonal sides thereof and disposed between the adjacent main cutouts (42c) formed on the main intermittent channel (42).

16. The electrical fluid heater (100) as claimed in any of the previous claims, wherein the main intermittent channels (42) are in fluid communication with each other through the first and second side-cutouts (44c) and (46c) formed on the side intermittent channels (44) and (46) respectively.