US20100126432A1

US20100126432A1 - Heat recovery device

Info

Publication number: US20100126432A1
Application number: US12/591,274
Authority: US
Inventors: Giorgio Eberle; Massimo Mazzega
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-11-24
Filing date: 2009-11-16
Publication date: 2010-05-27
Also published as: EP2189745A1; ITTV20080151A1

Abstract

A heat recovery device, particularly for reducing energy consumption in heating sanitary water for residential use or for industrial use by reducing the temperature of the combustion gases and of the particles dispersed by stacks of heating boilers. The device consists of a tubular element, which has an inlet for the water drawn from the aqueduct, which flows along a coil of tubes up to the exit toward the heating boiler. The tubular element also has an opening for the inflow of the combustion gases that arrive from the heating boiler and exit through a second opening after flowing around the coil that contains the water drawn from the aqueduct. The device thus allows savings in heating water for domestic and industrial uses and also allows a reduction in the emission of fine particles.

Description

The present invention relates to a heat recovery device, particularly for stacks of boilers.

BACKGROUND OF THE INVENTION

Currently it is known to heat water both for residential uses and for industrial uses by means of boilers.
These devices can be supplied especially with fuels which, by burning, emit combustion gases which are expelled from the flues.
In this last case, water heating occurs due to the heat generated by the combustion of the various fuels, which however release into the environment high-temperature combustion gases which are expelled from the flues, altering the surrounding bioclimate.
The use of these devices therefore requires energy and economic resources with high level for their operation, with the drawback of releasing into the environment a quantity of hot, high-temperature combustion gases that still have heat energy, which is lost.
Another drawback of this known method is that the high-temperature combustion gases disperse into the environment fine particles originating from combustion, which are very harmful to one's health.

SUMMARY OF THE INVENTION

The aim of the present invention is to solve the noted technical problems, eliminating the drawbacks of the cited background art, by providing a heat recovery device that allows reduction of the temperature at which the combustion gases of heating boilers are expelled from the flues, improving the thermal yield of the boilers.
Within this aim, an object of the invention is to provide a device that makes it possible to reduce, in heating boilers or other heat generators for heating water, the difference in temperature between the input water from the aqueduct and the desired value in output.
Another object is to provide a device that makes it possible to reduce the calories needed to heat the water up to the desired temperature in boilers or other heat generators.
Another object of the invention is to allow a reduction of the quantity of fine particles emitted by heating boilers into the surrounding environment.
Another object is to obtain a device that is effective, structurally simple, and can be provided at low cost.
This aim and these objects, as well as others that will become better apparent hereinafter, are achieved by a heat recovery device, characterized in that it comprises a tubular element, which is interposed between two ends of a stack or flue and is provided internally with at least one removable coil which has a first input connector which is connected to the aqueduct or to a well and a second output connector for sending the heated water toward devices that are adapted to heat it further or to accumulation tanks.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will become better apparent from the following detailed description of a particular but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a sectional view of a device according to the invention, arranged in a vertical position, suitable to allow the viewing of the components inside it and the hydraulic connections in the condition for use in countercurrent;

FIG. 2 is a front view of the double-comb locking means;

FIG. 3 is a perspective view of the diffuser cone and of its support;

FIG. 4 is a plan view of the diffuser cone and of its support;

FIG. 5 is a perspective view of of the heat recovery device with the cover uncoupled from the tubular element;

FIG. 6 is a partially sectional schematic view of a possible application of the device;

FIG. 7 is a schematic view of a possibility of application of the device with a plurality of modules in a cascade arrangement for serving heating boilers;

FIG. 8 is a partially sectional schematic view of the device coupled to a tank for accumulating the heated water;

FIG. 9 is a partially sectional view of the heat recovery device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the exemplary embodiments that follow, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.
Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.
The terms “lower”, “top”, “upper”, “upwardly” and similar, are hereinafter used with reference to the position of the device and other parts as shown in the enclosed figures.
With reference to the figures, the reference numeral 1 designates a heat recovery device, which comprises a tubular element 2 which is hollow and cylindrical and is interposed between two ends of a flue 3 or stack.
The tubular element 2 is provided internally with at least one coil 4 of tubes which can be extracted and has a first connector 5, which is connected to the aqueduct or to a well, for the inflow of water; the first connector 5 is arranged proximately to a lower end 6 of the tubular element 2 and conveys, through a first vertical portion 5 a that lies inside the coil 4, the water up to the top of the tubular element 2.
The coil of tubes 4 extends until it approximately skims the internal lateral surface of the tubular element 2, forming a series of circular turns, which are supported by a double-comb locking means 7 composed of two pairs of linear flanges 7 a, 7 b which are mutually opposite and have a series of seats for positioning and resting portions of tube that constitute the coil 4.
The locking means 7, shown in FIG. 2, is fixed to the tubular element 2 by means of screws 8, which pass through appropriately provided holes formed in said element and which, once unscrewed, allow the simultaneous extraction of the locking means 7 and of the coil 4 by means of a handle 9 that can be gripped by a user since it is arranged transversely to the upper end of the locking means 7.
Advantageously, the pipes of the coil 4 are of the non-rigid type, and have the particularity of contracting the coil 4 if the pressure of the fluid contained therein decreases.
The path of the coil 4 ends in a second output connector 11, which is arranged at the lower end 6 of the tubular element 2 and enters a first duct 12 for sending the heated water toward accumulation tanks 30 or toward devices that are adapted to heat it further, such as boilers 31 or heat generators.
The stream of combustion gases 13 that exit from the boiler 31 are conveyed into the flue 3, which engages the lower end 6 by means of a frustum-shaped portion that tapers along the vertical axis and ends with a third tubular connector 14, which has a circular cross-section and a first opening 15.
The stream of combustion gases 13 that enter from the first opening 15 is advantageously conveyed radially in the direction of the coil of tubes 4 by one or more diffuser cones 16, which preferably are three and are arranged along the central axis of the tubular element 2 in order to facilitate better heat exchange between the stream of the combustion gases 13 and the water that flows within the coil of tubes 4.
The diffuser cones 16, shown in FIG. 3, are fixed to the locking means 7 by anchoring means 17 consisting of two rods 18, which are mutually connected in an X-shaped arrangement and have, at their ends, suitable holes 19 which act as seats for locking screws.
During heat exchange, therefore, the stream of combustion gases 13 is cooled, entailing the appearance of condensation, which is conveniently collected in a condensation recovery means 20 arranged at the lower end 6 in a region that is proximate to the first opening 15, the condensation recovery means 20 preferably having a concave tray-like shape provided with a drain tube 21.
The condensation that forms is collected by means of the drain tube 21 in a dust recovery tank 22, which can be inspected and opened for cleaning and is usually arranged below the tubular element 2.
These combustion gases, after passing through the tubular element 2, exit from an upper end 10, flowing inside a cover 23, which is removable and frustum-shaped and ends with a portion that tapers toward the upper part and is provided with a second opening 24.
The cover 23 is detachably engaged with the upper end 10 of the tubular element 2, for example with a coupling or a threaded closure (not shown in the figures) for allowing easy inspection of the inside of the tubular element 2.
FIG. 3 shows how the heat recovery device is connected to the flue 3; in particular, it is shown how the flue 3 is engaged in the first opening 15 and continues after the outlet of the second opening 24.
Thermometers are placed for checking correct operation and efficiency of the heat recovery device: more precisely, there is a first thermometer 25, which is associated with the first connector 5 for the input of the water that arrives from the aqueduct, a second thermometer 26, which is associated with the second connector 11 at the exit of the water from the tubular element 2, a third thermometer 27 for measuring the temperature of the combustion gases that enter the device 1, which is associated with the third connector 14 of the lower end 6, and finally a fourth thermometer 28 for measuring the temperature of the combustion gases in output, which is placed on the cover 23.
The present heat recovery device can be simply arranged at the output of a boiler 31 and therefore serves a single residential use, as shown in FIG. 6, or inserted in a plurality of modules in a cascade arrangement to serve a plurality of boilers 31, for example in condominiums as shown in FIG. 7.
The operation of the device is as follows.
The boiler, by starting operation both to heat sanitary water and to heat rooms, burns fuel, thus emitting hot combustion gases which are directed to the flue 3.
The water that arrives from the aqueduct, at ambient temperature, is not routed directly to the boiler 31 but flows first inside the tubular element 2 interposed between two ends of the flue 3 and only then collects in the boiler 31.
When the hot water is demanded by the user, both residential and industrial, for example by opening a tap, the supply water from the aqueduct enters the first connector 5, where there is a first thermometer which measures its temperature, and subsequently begins to flow within the coil of tubes 4.
The demand for hot water starts the boiler 31, which emits combustion gases, which enter the flue 3 and pass through the first opening 15, skimming the coil of tubes 4.
The stream of combustion gases 13 is guided inside the tubular element 2 by the diffuser cones 16, which add to the stream of combustion gases 13, which previously was substantially vertical, a radial component, thus creating greater turbulence around the coil of tubes 4, thus increasing heat exchange.
The water, by flowing through the entire coil of tubes 4 in countercurrent, after being conveyed to the top of the tubular element 2 by means of the first connector 5, acquires heat from the combustion gases which reach the second output connector 11 at the lower end 6 with a higher temperature than that of the water that arrives from the aqueduct.
After flowing through the entire device, the water enters the boiler 31, thus requiring fewer calories for further heating up to the desired temperature.
Moreover, the hot combustion gases at the output of the boiler 31 undergo cooling before they are introduced in the environment, leading to a suppression of emitted fine particles.
Condensation caused by heat exchange can in fact form inside the tubular element 2 and, by descending in countercurrent with respect to the stream of combustion gases 13, captures the fine particles, collecting in the condensation recovery means 20.
The generated condensation, which contains the impurities of the combustion of the gases, descends from the condensation recovery means 20 through the drain tube 21 down to the particle recovery tank 22, which can be inspected and opened for cleaning.
During heat exchange, in addition to condensation, impurities can form which can deposit on the outer surface of the coil of tubes 4, thus reducing heat conductivity between the tubes and the stream of combustion gases 13.
However, these impurities are removed whenever the boiler demands water, for example when the user opens a hot water tap, because the pressure inside the tube decreases and the tube reacts by compressing axially.
The axial movement, caused by the contraction of the coil of tubes 4, upon the variation of the pressure of the fluid inside it, leads to the breakup and fragmentation of the impurities that might form on the pipes, such impurities descending by gravity toward the condensation recovery means 20.
If the user demands only heating of the rooms, the stream of hot combustion gases 13 heats the water that is present inside the coil of tubes 4, making it available at a higher temperature for subsequent use.
One possible arrangement of the heat recovery device can provide for the presence of the accumulation tank 30, which is arranged so as to receive the water in output from the tubular element 2 before it is conveyed into the boiler 31.
The accumulation tank 30 has a fifth thermometer 38 for measuring the temperature of the water contained therein.
In this case, a second duct 29, which is connected to the second connector 11 for the outflow of the water from the tubular element 2, is connected to the lower region of the accumulation tank 30, and a circulation pump 32 is inserted in the second duct 29.
The accumulation tank 30 further has a third delivery duct 33, which is arranged in the upper region; the third duct 33 continues by splitting into a fourth duct 34 for entering the boiler and a fifth duct 35 which ends with a first redirection valve 36, which is arranged in the pipe of the aqueduct 37, which in turn is connected to the first connector 5 of the tubular element 2.
For allowing the formation of a closed circuit between the accumulation tank 30 and the device 1, there is a second redirection valve 40, which intercepts the fourth duct 34 and the fifth duct 35.
For the use of sanitary water, operation is as described earlier; the accumulation tank 30 receives water at a higher temperature than the water of the aqueduct if the heating system is in operation.
If instead the boiler operates only for room heating, the first redirection valve 36 is activated automatically, preventing the inflow of the water of the aqueduct in the tubular element 2, and simultaneously the circulation pump 32 is started, allowing the water of the accumulation tank 30 to flow within the tubular element 2, circulating within the closed circuit formed between the accumulation tank 30 and the device 1, in turn being heated and being thus ready for any subsequent use.
The device can also be inserted horizontally and can thus adapt to any arrangement of the flue 3.
The device that has just been described has a heat exchange in countercurrent, but it is also possible to achieve heat exchange in equicurrent if this is more favorable for operating reasons.
This last case requires the swapping of the connections between the intake and the delivery.
The device therefore makes it possible to recover the heat of the stream of combustion gases by heating the sanitary water before it enters the boiler, reducing considerably the difference in temperature between the water that arrives from the aqueduct or well and the temperature desired by the user.
It has thus been found that the invention has achieved the intended aim and objects, a device having been devised which makes it possible to reduce energy consumption and reduce emissions of fine particles generated by combustion in order to obtain hot water to be used for industrial or civil purposes.
Of course, the materials used, as well as the dimensions that constitute the individual components of the invention, may be more pertinent according to specific requirements.
The various means for performing certain different functions need not certainly coexist only in the illustrated embodiment but can be present per se in many embodiments, including those that are not illustrated.
The characteristics indicated as advantageous, convenient or the like may also be omitted or replaced with equivalents.
The disclosures in Italian Patent Application No. TV2008A000151 from which this application claims priority are incorporated herein by reference.

Claims

1. A heat recovery device, comprising: a tubular element, which is interposable in use between two opposite ends of a stack or flue; at least one removable tube coil provided internally to said tubular element, said removable coil having a first input connector, which is connectable to an aqueduct or to a well, and a second output connector for sending heated water to devices for further heating or to accumulation tanks.

2. The device of claim 1, wherein said first connector is arranged proximately to a lower end of said tubular element and comprises a double-comb locking means and a first vertical portion which is internal to said tube coil, and is suitable for conveying aqueduct or well water to a top part of said tubular element, said tube coil being arranged extending inside, and so as to skim an internal lateral surface of said tubular element, and to form a series of circular turns, said circular turns being supported by said double-comb locking means.

3. The device of claim 2, wherein said double-comb locking means comprises: a handle arranged transversely to an upper end of said double-comb locking means; and two pairs of linear flanges, which are located mutually opposite and have a series of seats for positioning and resting thereon portions of tube that constitute said tube coil, said double-comb locking means being fixed to said tubular element by way of screws, which are provided passing through holes formed in said tubular element, simultaneous extraction of said locking means and of said tube coil being performable, upon unscrewing of the screws, by way of said handle that can be gripped by a user.

4. The device of claim 3, wherein said tubes of said tube coil are of a non-rigid type, said tube coil being able to contract if pressure of fluid contained therein decreases and to expand when the pressure increases.

5. The device of claim 4, wherein said tubular element is cylindrical and hollow and has, at said lower end, a portion that tapers along a vertical axis thereof and is frustum-shaped for connection to a flue, said lower end terminating with a third tubular connector, which has a circular cross-section and a first opening, said tubular element being suitable for connection at an outlet of at least one boiler or for insertion in a plurality of modules in a cascade arrangement to serve said at least one boiler provided in a condominium heating system.

6. The device of claim 5, comprising anchoring means consisting of two rods, which are mutually connected in an X-shaped arrangement, said two rods having, at ends thereof, holes for accommodating locking screws, said tubular element comprising at least one diffuser cone and in a preferred embodiment three diffuser cones arranged along the vertical axis of said tubular element, for facilitating better heat exchange between a stream of combustion gases and water that flows inside said tube coil, said diffuser cones being fixed to said double-comb locking means by way of said anchoring means.

7. The device of claim 6, wherein said tubular element is provided, in a region proximate to said first opening, with condensation recovery means for recovering condensation, said condensation recovery means having a drain tube connected to a particle recovery tank, of a type that allows inspection and opening for cleaning, which is arranged below said tubular element, and wherein said condensation recovery means has preferably a tray concave shape.

8. The device of claim 1, comprising a cover, which is engaged detachably with an upper end of said tubular element, said cover having a frustum shape which terminates in a portion that tapers upwardly and is provided with a second end opening.

9. The device of claim 5, comprising: a first thermometer, which is associated with said first connector for inflow of water that arrives from an aqueduct or from a well; a second thermometer, which is associated with said second connector at a water outlet of said tubular element; a third thermometer, which is associated with the third connector arranged at said lower end, and with a fourth thermometer for measuring temperature of combustion gases in output, which is arranged on said upper end.

10. The device of claim 1, comprising: an accumulation tank arranged so as to receive water in output from said tubular element before conveyance thereof into at least one boiler; a second duct being further provided which is connected to said second connector for water outflow from said tubular element and connected to a lower region of said accumulation tank; a circulation pump being inserted in said second duct; a third duct provided for delivery in output from an upper region of said accumulation tank, said third duct continuing with and splitting into a fourth duct for entering the at least one boiler; a fifth duct which terminates with a first redirection valve which is arranged in a pipe of an aqueduct that is connected to said first connector of said tubular element, in order to allow formation of a closed circuit between said accumulation tank and the heat recovery device; and a second redirection valve provided so as to intercept said fourth and fifth ducts.