AU2021105755A4

AU2021105755A4 - Fluid heating system

Info

Publication number: AU2021105755A4
Application number: AU2021105755A
Authority: AU
Inventors: Yuchen Guo; Yikun Li; Bo QIN; Likun XU; Xiaodong Yang
Original assignee: Hangzhou Fulton Thermal Energy Equipment Co Ltd
Current assignee: Hangzhou Fulton Thermal Energy Equipment Co Ltd
Priority date: 2021-08-18
Filing date: 2021-08-18
Publication date: 2021-11-11
Anticipated expiration: 2029-08-18

Abstract

The invention discloses a fluid heating system comprising: a pressure vessel shell comprising a first inlet and a first outlet; tubeless heat exchanger core, the tubeless heat exchanger core is all arranged in the pressure vessel shell, the tubeless heat exchanger core includes a second inlet and a second outlet; an outlet member passing through the pressure vessel shell and connecting the second outlet of the tubeless heat exchanger core with the outer side of the pressure vessel shell; and a tube having a first end connected to a second inlet of the tubeless heat exchanger core and a second end disposed outside the pressure vessel housing. 2/5 200 201 242 2 210 212 253 25222 251 222 270 230 271 240 211 221 220 260 -~~~r254 Figure 2

Description

2/5

200 201 242 2 210

212

253

25222 251 222 270 230

271

240

211

221

220 260 -~~~r254 Figure 2

Fluid heating system

TECHNICAL FIELD

The invention relates to a fully wet heat-resistant material tubeless fluid heating

system which can ignore thermal expansion stress.

BACKGROUND

Fluid heating systems are used to provide heated production fluids for various

commercial, industrial, and domestic applications such as hot water, steam, and hot

fluid boilers. Improved fluid heating systems and improved manufacturing methods

are still needed due to expectations for improved energy efficiency, compactness,

reliability and cost reduction.

SUMMARY

The invention discloses a fluid heating system, which comprises a pressure

vessel shell comprising a first inlet and a first outlet; tubeless heat exchanger core, the

tubeless heat exchanger core is all arranged in the pressure vessel shell, the tubeless

heat exchanger core includes a second inlet and a second outlet; an outlet member

passing through the pressure vessel shell and connecting the second outlet of the

tubeless heat exchanger core with the outer side of the pressure vessel shell; and a

tube having a first end connected to a second inlet of the tubeless heat exchanger core

and a second end disposed outside the pressure vessel housing.

The invention also discloses a fluid heating system, specifically, it includes: a

pressure vessel housing including a first inlet and a first outlet, a cylindrical housing,

a first top head and a first bottom head, wherein the cylindrical housing is disposed

between the first top head and the first bottom head, and wherein the first inlet and the first outlet are each independently positioned on the cylindrical housing, the first top head or the first bottom head; tubeless heat exchanger core, the tubeless heat exchanger cores are all arranged in the pressure vessel shell, the tubeless heat exchanger core comprises a cylindrical inner shell, a cylindrical outer shell, a rib arranged between the inner shell and the outer shell, a second top head, a second bottom head, a second inlet and a second outlet, wherein the cylindrical inner shell is surrounded by the cylindrical outer shell, wherein both the cylindrical outer shell and the cylindrical inner shell are located between the second top head and the second bottom head, and wherein the second inlet and the second outlet are each independently located on the cylindrical outer shell, the second top head or the second bottom head; an outlet member that connects the second outlet to an exhaust flue provided outside the pressure vessel housing; a pipe passing through the pressure vessel housing, wherein a first end of the pipe is connected to the second inlet, and wherein the second end of the pipe is located outside the pressure vessel housing; a burner arranged in the pipeline; and a fan in fluid communication with the second end of the duct.

The invention has the beneficial effects of:

The invention discloses a fluid heating system, which improves thermal

efficiency, shortens preheating time, reduces electric energy loss, reduces production

cost, and has less heat dissipation to ensure long-term safe and reliable operation of

equipment.

BRIEF DESCRIPTION OF THE FIGURES

In order to more clearly explain that embodiment of the invention or the

technical proposal in the prior art, the drawings required for use in the embodiments

will be briefly described below, and it will be apparent that the drawings described

below are only some embodiments of the present invention, from which other

drawings may be obtained without creative effort by a person of ordinary skill in the

art.

Fig. 1 is a schematic diagram of a tubeless heat exchanger 100 in an embodiment

of the present invention;

Fig. 2 is a schematic diagram of a tubeless heat exchanger 200 for a fluid heating

system in an embodiment of the present invention;

Fig. 3 is a perspective view of an embodiment of a fluid heating system in an

embodiment of the present invention;

Fig. 4 is a cross-sectional view of another embodiment of a fluid heating system

in an embodiment of the present invention;

Fig. 5 is a perspective view of an embodiment of a heat exchanger core in an

embodiment of the present invention.

DESCRIPTION OF THE INVENTION

In order that the above objects features and advantages of the present invention

can be more clearly understood the invention will be described in further detail below

in conjunction with the accompanying drawings and detailed description.

The fluid heating system is ideally thermally compact, which provides a high

ratio of the heat output of the fluid heating system to the overall specification, and has a design that can be manufactured at a reasonable cost. This is particularly true for hot fluid heating systems and heating systems using hot water (e.g. liquid water), steam, where hot fluid heating systems are intended to provide heated production fluids such as steam for temperature regulation, domestic hot water, or commercial or industrial process applications. In a fluid heating system, a heat transfer fluid comprising, for example, a hot combustion gas is generated by combustion of the fuel and heat is then transferred from the heat transfer fluid to the production fluid using a heat exchanger.

The design of shell-and-tube heat exchanger suffers from various disadvantages.

In a shell-and-tube heat exchanger, heat is transferred from the heat transfer fluid to

the production fluid through the wall surfaces of many thin-walled fluid tubes, such as

tubes with a wall thickness of less than 0.5 cm (cm). These tubes are rigidly

connected to the tube sheet. Operating factors, including thermal stress and corrosion,

cause undesired material failures in tubes, tube attachments, and tube sheets of

shell-and-tube heat exchangers. Furthermore, when failure occurs, the fluid heating

system becomes inoperable, and maintenance or replacement of thin-walled heat

exchanger tubes and/or tube sheets, especially in field installation, is difficult and

expensive. Shell-and-tube heat exchangers suffer thermal stress material failures

caused by the difference in longitudinal thermal expansion of the heating components,

for example, the thermal expansion of the burner and heat exchanger assemblies

relative to the thermal expansion of the pressure vessel shell. Material failures in

slender heat exchanger tubes and other structural members may be initiated by rigidly

attaching the burner and heat exchanger assemblies to the pressure vessel housing.

Techniques available in practice for reducing thermal stress in shell-and-tube heat

exchangers are flawed. For example, the floating head assembly is complex and

located in the pressure vessel housing, so it is difficult to repair. Alternatively

compliance is added to slender heat exchanger tubes containing arcs and bends but

increases manufacturing costs and the risk of material failure. In addition compliant

elements such as bellows or expansion joints within pressure vessel shells result in

poor maintainability of systems and assembly areas.

Tubeless heat exchangers are also used. Tubeless heat exchangers avoid the use

of thin-walled tubes and tube sheets associated with shell-and-tube heat exchangers.

Fig. 1 shows a tubeless heat exchanger 100 in which a pressure vessel housing 110 is

exposed to hot combustion gases resulting in a hot surface on an outer surface 120 of

the pressure vessel housing 110. As shown in fig. 1 Fan 130 forces air through

Conduit 132 and into Burner 140. The burner generates hot combustion gas and the

hot combustion gas exits the core 150 of the heat exchanger and then contacts the

outer surface 120 of the pressure vessel housing 110 and the inner surface 160 of the

heat resistant material layer 170 and then exits the heat exchanger through the outlet

port 180. A heat-resistant material layer 170 is disposed on the body cover 190. The

pressure vessel housing is provided with a production fluid that contacts an inner

surface 111 of the pressure vessel housing 110 and an outer surface 151 of the core

150. Thermal energy is transferred from the hot combustion gas to the heat exchanger

core 150 and then to the production fluid, and also from the hot combustion gas to the

pressure vessel housing 110 and then to the production fluid. Thus, the pressure vessel housing and the heat-resistant material layer are exposed to the combustion gas and can be in direct contact with the combustion gas. A disadvantage of this design is that heat and combustion gases can be transferred through the heat resistant material layer

170 and into the surrounding environment by convection and conduction. In addition,

the core 150, the pressure vessel housing 110, and the heat-resistant material layer 170

may each contact the combustion gas, and thus each of the pressure vessel housing

110 and the heat-resistant material layer 170 is desirable to be composed of a material

that is stable in the hot combustion gas pressure. Such tubeless designs suffer thermal

degradation and loss of thermal efficiency due to some heat transfer into and through

cracks in the heat-resistant layer and ultimately into the environment surrounding the

heat exchanger. In addition, flue gas, which may include CO, may leak through cracks

in the heat-resistant layer and enter the occupied area instead of flowing to the flue

gas discharge chimney, thus causing health hazards. In addition, the hot outer surface

of the pressure vessel shell has safety problems in the case of heat transfer fluid

leakage. In addition, the flow path of combustion gas is relatively short, which may

lead to lower than desired thermal efficiency.

A tubeless heat exchanger 200 for a fluid heating system is disclosed in fig. 2,

the tubeless heat exchanger comprises: a pressure vessel housing 210, a tubeless heat

exchanger core 220, an outlet member 230 and a conduit 240, wherein the pressure

vessel housing 210 includes a first inlet 211 and a first outlet 212, tubeless heat

exchanger core 220 is integrally disposed in the pressure vessel housing, the tubeless

heat exchanger core 220 includes a second inlet 221 and a second outlet 222, the outlet member 230 passes through the pressure vessel housing and connects the second outlet 222 of the tubeless heat exchanger core with the outer side of the pressure vessel housing, and the duct 240 has a first end connected to the second inlet

221 of the tubeless heat exchanger core and a second end 242 disposed on the outer

side of the pressure vessel housing.

When in use the pressure vessel housing 210 may be filled with a production

fluid and the heat exchanger core 220 may contain a heat transfer fluid. The

production fluid may be directed from the first inlet 211 of the pressure vessel

housing to the first outlet 212. The heat transfer fluid may be directed from the duct

240 through the second inlet 221 and into the flow passage of the tubeless heat

exchanger core 220 before passing through the second outlet 222 and continuing out

of the heat exchanger core 220 through the outlet member 230. The flow passage of

the tubeless heat exchanger core is located between the second inlet 221 and the

second outlet 222 of the heat exchanger core 220 and may be defined by an inner shell

251, an outer shell 252, a top head 253, and a bottom head 254. Thus, the entire outer

surface of the tubeless heat exchanger core may be contacted by the production fluid

when the production fluid is directed into the pressure vessel housing, e.g. to fill the

pressure vessel housing. In addition, the whole flow channel of the tubeless heat

exchanger core can be completely arranged in the pressure vessel shell. As shown in

fig. 2, the entire outer surface of the heat exchanger core, such as the outer surfaces of

the inner shell 251, the outer shell 252, the top head 253, and the bottom head 254, is

contacted by the production fluid, thereby providing an increased surface area of the heat exchanger core that is contacted by the production fluid, thereby improving thermal efficiency. 60% to 100%, or 70%, 80%, or 90% to 99%, 98%, or 95% of the outer surface of the heat exchanger core may be contacted by the production fluid, wherein the upper and lower bounds may be independently combined. Alternatively,

% to 100%, or 70%, 80%, or 90% to 99%, 98%, or 95% of the heat exchanger core

is contained in the pressure vessel housing, wherein the upper and lower bounds can

be independently combined. 100% of the exterior surface of the heat exchanger core

is in contact with the production fluid, and the entire heat exchanger core is contained

in the pressure vessel shell, which is the optimal choice.

As shown in fig. 2, the outlet member of the tubeless heat exchanger core and the

second end of the tube are both proximate to the first end 201 of the fluid heating

system, and thus the rigid connection between the pressure vessel housing 210 and the

heat exchanger core 220 is on the same end of the pressure vessel housing and the

heat exchanger core. By providing a rigid connection between the heat exchanger core

and the pressure vessel housing at the same end of the heat exchanger core, the heat

exchanger core can be thermally expanded, expanding downward as shown in fig. 2,

without significant thermal stress, providing improved durability.

A debris region 260 is also provided in which debris such as corrosion products

or precipitates can accumulate thereby avoiding the formation of accumulation of

debris adjacent to the heat transfer surface. Although it is not desirable to be bound by

theory, it should be understood that the accumulation of debris can form insulating

barriers, resulting in thermal gradients or local hot spots that can lead to material failure. A debris region 260 is disposed between the heat exchanger core 220 and the pressure vessel housing 210. The debris region may be disposed at any suitable location and may be located between the top head 253 of the tubeless heat exchanger core and the pressure vessel housing 210, between the outer shell 252 of the tubeless heat exchanger core and the pressure vessel housing 210, between the bottom head

254 of the tubeless heat exchanger core and the pressure vessel housing 210, or a

combination of these locations. In an embodiment the debris region is located

between the bottom head 254 and the pressure vessel housing 210 and away from the

outlet member and the second end of the conduit as shown in fig. 2.

As shown in fig. 4 the inner housing 451 the outer housing 452 or a combination

thereof may be deformed to provide a flow element in the form of a ridge 420. In an

embodiment, the average aspect ratio of the flow passages between the inner shell and

the outer shell is between 3, 5, 10, 100, 200 or 500, preferably 10 to 100, wherein the

aspect ratio is the ratio of the height of the flow channel to the width of the flow

channel, wherein the height is the distance between opposite surfaces of adjacent flow

elements and is measured in a manner normal to the surface of the first flow element,

and wherein the width of the flow channel is measured from the inner surface of the

inner shell to the inner surface of the outer shell, wherein both the outer shell and the

inner surfaces of the inner shell are inside the flow channel.

Tubeless heat exchanger core 220 may include a top head 253, a bottom head

254, an inner shell 270 disposed between the top and bottom heads, an outer shell 271

disposed between the top and bottom heads, wherein, the inner surface of the inner shell is opposite to the inner surface of the outer shell, a flow element such as a rib

320 is disposed between the inner housing and the outer housing, wherein the flow

element, the inner shell, and the outer shell define a flow passage between a second

inlet and a second outlet of the heat exchanger core, wherein the second inlet of the

tubeless heat exchanger core is disposed on the inner shell, the outer shell, or a

combination thereof, and wherein the second outlet of the tubeless heat exchanger

core is disposed on the inner shell, the outer shell, or a combination thereof.

The second inlet 221 and the second outlet 222 of the heat exchanger core may

each be independently located on the inner housing 270 or the outer housing 271 of

the heat exchanger core. Additionally the second inlet 221 and the second outlet 222

may each independently proximate to or away from the first end 201 of the fluid

heating system for example proximate to or away from the first outlet 212 of the

pressure vessel housing. As shown in fig. 2, in a preferred embodiment, a second inlet

221 is disposed on the inner housing 270 and away from the first end of the fluid

heating system, and a second outlet 222 is disposed on the housing 271 and close to

the first end of the fluid heating system.

The inner shell and the outer shell may each have any suitable shape, and may

each independently have a circular cross-sectional shape, an elliptical cross-sectional

shape, an oval cross-sectional shape, a stadium cross-sectional shape, a semicircular

cross-sectional shape, a square cross-sectional shape, a rectangular cross-sectional

shape, a triangular cross-sectional shape, and combinations thereof. In a preferred

embodiment, the inner shell and the outer shell have the same cross-sectional shape, and in a more preferred embodiment, the inner shell and the outer shell each have a circular cross-sectional shape. The inner shell and the outer shell can be coaxial if necessary.

The heat exchanger core can have any suitable size. Specific mention is made of

the case where the inner shell and the outer shell may each independently have a

maximum outer diameter of 15 cm (cm), 25cm, 30cm, 350cm, 650cm, or 1,400 cm,

wherein the foregoing upper and lower limits may be independently combined. For

example, the inner shell and the outer shell may each independently have a maximum

outer diameter of 15cm to 1,400 cm. Embodiments in which the inner shell and the

outer shell each independently have a maximum outside of 30cm to 350cm are

preferred.

The inner shell and the outer shell may each independently have a maximum

height of 15 cm (cm), 25cm, 30cm, 350cm, 650cm, or 1,400 cm, wherein the

foregoing upper and lower limits may be independently combined. For example, the

inner shell and the outer shell may each independently have a maximum height of

cm to 1,400 cm. Embodiments in which the inner shell and the outer shell each

independently have a maximum outer diameter of 30cm to 650cm are preferred.

The thickness of the top head, the bottom head, the inner shell, and the outer

shell, such as an average thickness, may be any suitable size, and the thickness of the

top head, the bottom head, the inner shell, and the outer shell may each be

independently 0.5 cm, 0.6 cm, 0.7 cm, or lcm to 5cm, 4cm, 3.5 cm, or 3cm, wherein

the upper and lower limits may be independently combined. Particular mention is made of embodiments in which the top head, the lower head, the inner shell and the outer shell each independently have a thickness of 0.5 cm to lcm.

The top head, the bottom head, the inner shell, the outer shell, the inlet, the outlet,

the pressure vessel housing, the inlet member, and the outlet member may each

independently comprise any suitable material. Special mention is made of the use of

metals. Representative metals include iron, aluminum, magnesium, titanium, nickel,

cobalt, zinc, silver, copper, and alloys including at least one of the foregoing.

Representative metals include carbon steel, mild steel, pig iron, wrought iron,

stainless steel (e.g. 304, 316 or 400 series stainless steel including 439 stainless steel),

model alloy, chromium-nickel-iron alloy, bronze and brass. Particular mention is

made of embodiments in which the heat exchanger core and the pressure vessel

housing each comprise steel.

As shown in fig. 3 the fluid heating system may also include a body shroud 300

disposed on the pressure vessel housing. The body cover may be of any suitable size

and may be of a size adapted to receive the pressure vessel housing and the fan 310 as

shown in fig. 3. In an embodiment, the body cover surrounds at least a top surface and

a side surface of the pressure vessel housing. The body cover may be provided on the

top surface of the pressure vessel housing as well as on the front surface, the rear

surface, the left surface and the right surface, if desired. In embodiments, the body

cover may also be located on the bottom of the pressure vessel housing as desired.

The body cover may have any suitable shape and may be curved, straight, or a

combination thereof. The body cover may have a circular cross-sectional shape, an elliptical cross-sectional shape, an oval cross-sectional shape, a stadium cross-sectional shape, a semicircular cross-sectional shape, a square cross-sectional shape, a rectangular cross-sectional shape, a triangular cross-sectional shape, or a combination thereof, as desired. Special mention is made of the rectangular body cover.

The heat exchanger core, pressure vessel housing, and body cover 300 may each

independently comprise any suitable material, and may comprise metals such as iron,

aluminum, magnesium, titanium, nickel, cobalt, zinc, silver, copper, and alloys

including at least one of the foregoing. Typical metals include carbon steel, mild steel,

pig iron, wrought iron, stainless steel (e.g. 304, 316 or 439 stainless steel), Model

alloy, Cr-Ni-Fe alloy, bronze, and brass.

The heat exchanger core consists of an inner shell, an outer shell, a top head, a

bottom head, an inlet and an outlet. When the pressure vessel housing is in use, such

as filled with a production fluid, since the entire outer surface of the heat exchanger

core can contact the production fluid, a large surface for heat transfer can be provided,

thereby improving thermal efficiency.

The fluid heating system may be used to exchange heat between any suitable

fluid, i.e. a first fluid and a second fluid, wherein the first fluid and the second fluid

may each independently be a gas or a liquid. Thus, the disclosed fluid heating system

may be used as a gas-to-liquid, liquid-to-liquid, or gas-to-gas heat exchanger. In a

preferred embodiment, the first fluid directed through the heat exchanger core is a

heat transfer fluid and may be a combustion gas, such as gas generated by a fuel burner, and may include water, carbon monoxide, carbon dioxide, or a combination thereof. Further, the second fluid directed through the pressure vessel and contacting the entire outer surface of the heat exchanger core is a production fluid and may include water, steam, oil, hot fluid (e.g. hot oil), or a combination thereof. The hot fluid may include water, C2 to C30 diols such as ethylene glycol, unsubstantiated or substituted Cl to C30 hydrocarbons such as mineral oil, or halogenated Cl to C30 hydrocarbons where the halogenated hydrocarbons may be selectively further substituted, and the hot fluid may include molten salts such as potassium nitrate, sodium nitrate, lithium nitrate or combinations thereof, silicones or combinations thereof. Representative halogenated hydrocarbons include 1, 1, 1,

2-tetrafluoroethylene, pentafluoroethane, difluoroethylene, 1, 3, 3-tetrafluoropropene

and 2, 3, 3, 3-tetrafluoropropene, such as chlorofluoromethane (CFC) such as

halocarbon (HFC), halocarbon (HCFC), per fluorocarbon (PFC) or combinations

thereof. The hydrocarbons may be substituted or unsubstantiated aliphatic

hydrocarbons substituted or unsubstantiated alicyclic hydrocarbons or combinations

thereof. Hot fluid can be composed of alkaline organic compounds and inorganic

compounds. Further, the hot fluid may be used in diluted form, for example with

concentrations ranging from 3 to 10 percent by weight. Particular mention is made of

embodiments in which the heat transfer fluid is a combustion gas and comprises

liquid water, steam, or combinations thereof and the production fluid comprises liquid

water, steam, hot fluid, or combinations thereof.

The heat transfer fluid may be the product of combustion of a hydrocarbon fuel such as natural gas propane or diesel oil. Combustion may be supported by a fan 310 which directs an oxidant such as air optionally via a duct 350 into a burner assembly

330 which may be disposed in a duct 340. Duct 340 may be disposed between second

inlet 221 of heat exchanger core 220 and fan 310 and may receive burner assembly

330 to provide a furnace including duct and burner assembly.

The pressure drop on both sides of the heat exchanger is measured as the

difference between a first pressure determined at the first end 341 of the duct 340 and

a second pressure determined at the second outlet 222 of the outlet member 230 where

the heat transfer fluid enters. The first and second pressures may be determined by

measurement or calculation. Particular mention is made of a pressure drop of 0.5 kPa

to 40kPa between the first end 341 of the pipe 340 and the outer end of the outlet

member 334.

As shown in fig. 5 the tube 500 may include an elbow 510 which includes a first

bend 515 and a second bend 520. The first bend may include an angle theta 1 of 5

degrees to 45 degrees or 5 degrees, 10 degrees or 15 degrees to 90 degrees, 85 degrees,

degrees, 45 degrees, 40 degrees, wherein the aforementioned upper and lower

limits may be independently combined with respect to the direction of an axis 530 of

the tube between the first end 540 of the tube and thefirst bend 515, and wherein the

first bend is in a direction perpendicular to the inlet of the heat exchanger core. The

second bend may include a compound angle and the second bend may be in a

direction from the first bend 515 to the inlet 550 of the heat exchanger core. In an

embodiment, the conduit 500 intersects the inlet 550 of the heat exchanger core at an angle of 85 to 10 degrees, or 85 degrees, 80 degrees, or 75 to 45 degrees, 40 degrees, degrees, 20 degrees, or 10 degrees, where the aforementioned upper and lower limits may be independently combined with respect to the tangent of the inlet.

The disclosed fluid heating system provides a number of features. The outer

surfaces of the top and bottom heads can also contact the production fluid to further

improve the heat transfer efficiency. In addition, since the entire outer surface of the

heat exchanger core can be in contact with the production fluid, thermal stress within

the heat exchanger core can be reduced, resulting in improved durability. In addition,

since the pressure vessel housing does not contact the production fluid, the disclosed

heat exchanger avoids the appearance of undesired hot surfaces on the pressure vessel

housing and avoids the need to isolate the hot surfaces with a heat-resistant material.

In addition, the fluid heating system provides a configuration in which the heat

exchanger core can be thermally expanded without increasing thermal stress. In an

embodiment, the heat exchanger core is rigidly connected to the pressure vessel

housing at a single end, and since the end of the heat exchanger core provided with a

bottom head is not rigidly connected to the pressure vessel housing, the heat

exchanger core can thermally expand without increasing stress and can increase

length. A rigid connection between the core of the heat exchanger and the pressure

vessel housing is provided at the same end of the core, and thus the core can expand

while heating without increasing thermal stress, resulting in improved durability.

The above-described embodiment is only a description of the preferred mode of

the invention, and does not limit the scope of the invention. On the premise of not departing from the design spirit of the invention, various modifications and improvements made by ordinary skilled personnel in the field to the technical scheme of the invention should fall within the protection scope determined by the claims of the invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A fluid heating system comprising:

A pressure vessel housing including a first inlet and a first outlet;

Tubeless heat exchanger core, the tubeless heat exchanger core all arranged in

the pressure vessel shell, the tubeless heat exchanger core including a second inlet and

a second outlet;

An outlet member passing through the pressure vessel shell and connecting the

second outlet of the tubeless heat exchanger core with the outer side of the pressure

vessel shell;

And a tube having a first end connected to the second inlet of the tubeless heat

exchanger core and a second end disposed outside the pressure vessel housing.

2. The fluid heating system of Claim 1, wherein the pressure vessel housing is

configured to receive a production fluid such that the entire outer surface of the

tubeless heat exchanger core is contacted by the production fluid.

3. A fluid heating system according to any one of claims 1 to 2, wherein the

entire flow passage of the tubeless heat exchanger core is disposed entirely in the

pressure vessel housing.

4. A fluid heating system according to any one of claims 1 to 2, wherein the fluid

heating system has a first end and an opposite second end, and wherein the outlet

member of the tubeless heat exchanger core and the second end of the tube are both

proximate to the first end of the fluid heating system.

5. A fluid heating system according to any one of claims 1 to 2, wherein the tubeless heat exchanger core and the pressure vessel housing define a debris zone for debris accumulation between the tubeless heat exchanger core and the pressure vessel housing.

6. The fluid heating system of claim 5, wherein the debris region is remote from

the outlet member and remote from the second end of the conduit, the debris region is

located between the top head of the tubeless heat exchanger core and the pressure

vessel housing, between the housing of the tubeless heat exchanger core and the

pressure vessel housing, and between the bottom head of the tubeless heat exchanger

core and the pressure vessel housing, or a combination of the following positions.

7. The fluid heating system of any one of claims 1 to 2, wherein the second inlet

of the tubeless heat exchanger core is located on an outer surface of an inner shell of

the tubeless heat exchanger core.

8. The fluid heating system of any one of claims 1 to 2, further comprising a

body cover disposed on the pressure vessel housing.

9. The fluid heating system of Claim 8, wherein the body cover surrounds at least

a top surface and a side surface of the pressure vessel housing, and wherein no heat

resistant material is present between the body cover and the pressure vessel housing.

10. A fluid heating system according to any one of claims 1 to 2, wherein the

pressure vessel housing is not contacted by a heat transfer fluid.

11. The fluid heating system of any one of claims 1 to 2, wherein the tubeless

heat exchanger core comprises:

Top head;

Bottom head;

An inner shell arranged between the top head and the bottom head;

An outer shell disposed between the top head and the bottom head and opposite

the inner surface of the inner shell;

An inlet located on the inner shell, the outer shell or the inner shell and the outer

shell;

As well as

An outlet located on the inner shell, the outer shell or the inner shell and the

outer shell, wherein at least one of the inner shell and the outer shell includes a rib and

a ridge;

Wherein the inner shell and the outer shell define a flow passage between the

inlet and the outlet of the tubeless heat exchanger core;

Wherein the second inlet of the tubeless heat exchanger core is disposed on the

inner shell, the outer shell or the inner shell and the outer shell, and wherein the

second outlet of the tubeless heat exchanger core is disposed on the inner shell, the

outer shell or the inner shell and the outer shell.

12. The fluid heating system of Claim 11, wherein the flow passage is

completely contained within the pressure vessel housing.

13. The fluid heating system of Claim 11, wherein the inner housing is coaxial

with the outer housing.

14. The fluid heating system of claim 11, further comprising:

A production fluid located in the pressure vessel housing and outside the tubeless heat exchanger core, wherein the production fluid contacts the entire outer surface of the tubeless heat exchanger core; and a heat transfer fluid located in the flow passage of the tubeless heat exchanger core, wherein the production fluid and the heat transfer fluid each independently comprise a liquid, a gas, or a combination of liquid and gas.

15. The fluid heating system of any one of claims 1 to 2, wherein the conduit

further comprises a burner assembly disposed in the conduit.

16. The fluid heating system of any one of claims 1 to 2, further comprising a fan

in fluid communication with the duct.

17. The fluid heating system according to any one of claims 1 to 2, wherein, the

pipeline comprises an elbow, the elbow includes a first bend part and a second bend

part, the first bend includes an angle of 5 to 60 degrees relative to the direction of an

axis of the pipe between a first end of the pipe and the first bend, and wherein the first

bend is in a direction perpendicular to the inlet of the tubeless heat exchanger core,

the second bend includes a compound angle, and wherein the second bend is in a

direction from the first bend to the inlet of the tubeless heat exchanger core.

18. The fluid heating system of Claim 17, wherein the second bend includes a

compound angle, and wherein the second bend is in a direction from the first bend to

an inlet of the tubeless heat exchanger core.

19. A fluid heating system comprising:

Pressure vessel shell, the pressure vessel shell comprises a first inlet and a first

outlet, a cylindrical shell, a first top head and a first bottom head, wherein the

cylindrical housing is disposed between the first top head and the first bottom head, and wherein the first inlet and the first outlet are each independently located on the cylindrical housing, the first top head or the first bottom head;

Tubeless heat exchanger core, all the tubeless heat exchanger cores are arranged

in the pressure vessel shell, the tubeless heat exchanger core comprises a cylindrical

inner shell, a cylindrical outer shell, a rib arranged between the cylindrical inner shell

and the cylindrical outer shell, a second top head, a second bottom head, a second

inlet and a second outlet, wherein the tubular inner shell is surrounded by the tubular

outer shell, wherein both the cylindrical housing and the cylindrical inner housing are

located between the second top head and the second bottom head, and wherein the

second inlet and the second outlet are each independently located on the cylindrical

housing, the second top head or the second bottom head;

An outlet member that connects the second outlet to an exhaust flue disposed

outside the pressure vessel housing;

A pipe passing through the pressure vessel housing, wherein a first end of the

pipe is connected to the second inlet, and wherein a second end of the pipe is located

outside the pressure vessel housing;

A burner arranged in the pipeline; and a fan in fluid communication with the

second end of the duct.

FIGURES 1/5

Figure 1