ITUD20120113A1 - APPARATUS TO SOLID FUEL FOR AIR HEATING OF ONE OR MORE USERS, AND RELATIVE HEATING METHOD - Google Patents

Description

Description

"SOLID FUEL APPARATUS FOR AIR HEATING OF ONE OR MORE USERS, AND RELATIVE HEATING METHOD"

FIELD OF APPLICATION

The present invention relates to an air heating apparatus and method, fed with solid fuel, such as a biomass, in which the heat produced by a heat generator, such as a pellet stove, is used to increase the temperature of air to be distributed to one or more rooms to be heated.

In particular, the present invention can be used in the home, without however excluding other areas or applications in which one or more users are heated by air.

STATE OF THE TECHNIQUE

The use of biomass-fueled heat generators, such as for example pellet stoves, or wood-burning stoves or fireplaces, is known for the air heating of domestic environments. In particular, it is advantageous to channel and distribute the hot air, which is generated thanks to the heat exchange with the combustion fumes, in the rooms to be heated by means of distribution or channeling, such as for example fans or conveyors associated with ducts or ducting pipes. .

Furthermore, the need to contain the dimensions of said heat generators, especially in the home, may limit the thermal power that they are able to develop, and therefore may not be sufficient to heat a home, especially large ones. square footage, using the blown hot air.

An increase in the power of a biomass heat generator used for this type of heating would, in fact, result in a significant increase in the size of the generator itself and of the related smoke outlet and air delivery pipes, making it inconvenient, bulky and expensive. as well as unsightly, for home use.

Furthermore, the heat distribution means capable of moving high masses of air, being equally bulky, would have the drawback of also being noisy and unsuitable for installation inside a stove of the type in question.

An object of the present invention is to provide an apparatus and method for heating one or more domestic users, powered by solid fuel, which makes it possible to make the distribution of the heat produced by a biomass generator more effective and efficient, allowing the increase of the thermal power supplied by the generator itself, with the same overall dimensions of the latter.

A further object of the present invention is to provide an apparatus and method for heating which is capable of completely heating a house using the air as a heating fluid and which is silent, economical, compact and easy to install.

Still another object of the invention is to provide a heating apparatus and method capable of promptly and promptly coping with temperature variations, limiting the length of the transients, during start-up and shutdown.

In order to obviate the drawbacks of the known art and to obtain these and further objects and advantages, the Applicant has studied, experimented and implemented the present invention.

EXPOSURE OF THE FOUND

The present invention is expressed and characterized in the independent claims. The dependent claims disclose other characteristics of the present invention or variants of the main solution idea.

In accordance with the aforementioned purposes, a heating apparatus according to the present invention uses heated air to heat one or more users connected to it, such as for example one or more rooms, or rooms, of a house.

The apparatus according to the invention comprises a heat generator fed with solid fuel, in particular a biomass, having a combustion chamber and first heat exchange means which cooperate with the combustion chamber.

According to an aspect of the invention, the aforesaid first heat exchange means are configured to effect the heat exchange between the fumes deriving from the combustion of the biomass and a heat-carrying liquid which flows in the same first heat exchange means.

Furthermore, the heating apparatus also comprises second air-liquid heat exchange means, external and spaced from the aforementioned heat generator, in which air flows to be heated by heat exchange with the aforementioned heated liquid and which is distributed, or channeled, to the utilities to be heated. The second heat exchange means are fluidly connected to the first heat exchange means, so as to heat the air by means of the heated liquid coming from the same first heat exchange means.

A first heat exchange is then obtained between the biomass and the liquid, allowing to increase the potential of the heat generator, with the same dimensions, compared to a known biomass generator, thanks to the higher specific heat of the liquid used compared to the 'air.

Moreover, since there is a second heat exchange between the heated liquid and the air, in an external area and at a distance from the generator, the apparatus according to the present invention is easy, convenient and convenient to use also in the home.

In fact, even for the higher thermal powers required, the necessary increase in size of the heat generator is compensated by the greater efficiency of the heat exchange between the liquid and the combustion fumes. Furthermore, the required oversizing of the air heat exchange means does not impact either on the heating apparatus itself, or on the environment in which said apparatus is installed, since, as stated above, they can be advantageously installed in a separate room or compartment at a distance from the environment in which the aforementioned heat generator is installed.

According to an aspect of the present invention, the aforesaid second heat exchange means comprise at least one heat exchanger and a first distribution circuit, for the circulation of hot air from the heat exchanger to the users, and vice versa. The first circuit has at least one delivery section to the users and a return section from the users, to direct the air towards the aforementioned heat exchanger, in which a second circuit is also provided, equipped with a delivery duct and a return conduit, for the circulation of the liquid heated by the aforesaid first heat exchange means towards the heat exchanger, and vice versa.

A further aspect of the invention provides that the aforesaid second heat exchange means further comprise means for moving the air, such as for example a fan, associated with the return section of the first distribution circuit, for drawing the air from the users and push it at least towards the heat exchanger. Still another aspect of the invention provides that the apparatus comprises first temperature measuring means, such as probes, sensors, or the like, associated with the return section of the first circuit and suitable for transmitting an electrical signal relating to the temperature of the air therein. return section, and an electronic control unit, inside the aforementioned heat generator, suitable for receiving and processing the aforementioned electrical signal to carry out a feedback control of the biomass combustion, to maintain the aforementioned temperature in a neighborhood of a value set by a user.

An apparatus made according to the invention can also comprise second temperature measuring means associated with the delivery section of the distribution circuit and suitable for transmitting an electrical signal relating to the temperature of the air in this delivery section. An electronic control unit, inside the heat generator, is suitable for receiving and processing the aforementioned electrical signal to control the quantity of liquid circulating in the aforesaid second circuit, to maintain this temperature in a suitable range to ensure a suitable comfort in the aforementioned utilities.

Still another aspect of the invention provides that the apparatus comprises third temperature measuring means associated at least with the delivery duct of the second circuit and suitable for transmitting an electrical signal relating to the temperature of the liquid in the delivery duct itself, and an electronic unit control unit, internal to the heat generator, suitable for receiving and processing this electric signal in order to check the operating conditions of the liquid inside the second circuit and the aforementioned first heat exchange means.

In a variant, the apparatus comprises second heat exchange means concentrated in a single position from which the heated air is sent to the different users.

In another variant, the apparatus comprises a plurality of second heat exchange means distributed in the rooms of the different users and fluidly connected to the first heat exchange means of the heat generator.

The present invention also refers to a method for the air heating of one or more users, which comprises a first phase in which the combustion of a biomass is carried out in a combustion chamber of a heat generator, and in which it also occurs the heat exchange between the fumes deriving from such combustion and a heat-carrying liquid which flows inside first heat exchange means, inside the aforementioned heat generator and cooperating with the combustion chamber. The method under discussion also comprises a second phase in which the air to be heated and distributed to the users is made to flow inside second heat exchange means, of the air-liquid type, external and spaced from the heat generator, and fluidically connected. to the first heat exchange means, to be heated by the heated liquid coming from the latter.

ILLUSTRATION OF DRAWINGS

These and other characteristics of the present invention will become clear from the following description of a preferential embodiment, given by way of non-limiting example, with reference to the attached drawings in which:

- fig. 1 is a functional diagram of an apparatus according to the invention;

- fig. 2 is a schematic representation of a possible installation of the apparatus of fig. 1;

- fig. 3 is a variant of fig. 2;

- fig. 4 is another variant of fig. 2.

DESCRIPTION OF SOME FORMS OF IMPLEMENTATION

With reference to fig. 1, a heating apparatus according to the present invention is indicated by the numerical reference 10 and can be used to heat and distribute hot air to one or more users 11, in this case one or more rooms, or rooms, of a house.

The apparatus 10 comprises a heat generator by means of biomass combustion, in this case a pellet-fed stove 12, positioned in a room 13 which is distant, adjacent to or below the users 11. The stove 12 is equipped with a combustion chamber 17 and first heat exchange means, in this case a heat exchange chamber 14, adjacent to the combustion chamber 17 and containing a heat-carrying liquid, in this case water. Said heat exchange chamber 14 is essentially a fume-water heat exchanger, or a fume-liquid heat carrier in general. This proximity between the combustion chamber 17 and the heat exchange chamber 14 allows the fumes, generated by the combustion of biomass that occurs in the combustion chamber 17, to transfer their heat to the water present and circulating in the heat exchange chamber 14, which acts as the first heat exchange medium.

The apparatus 10 also comprises second heat exchange means 18 for air-water, or in general arial-liquid, which, unlike the state of the art, are an external entity, separate and spaced from the stove 12.

The second heat exchange means 18 comprise a fan 15, which acts as a means of movement for the heating air and a heat exchanger 16, which can be, for example, an air-water exchange battery, such as a tube bundle exchanger or a another type of exchanger capable of exchanging heat between a liquid, such as water, and the heating air.

The fan 15 has the function of circulating the heating air inside a first circuit, or distribution circuit 19, taking it from a return section 20 of the latter. In fig. 2, the arrows F indicate the path of the air along the distribution circuit 19. The aforementioned return section 20 acts as an intake duct for the fan 15, which takes the air coming from the users 11 and forcibly pushes it through the heat exchanger 16, in which the air is heated by the hot water coming from the heat exchange chamber 14. The air thus heated then exits from a delivery section 21 of the distribution circuit 19, which acts as a distributor duct through which the hot air is distributed to the users 11. The fan 15 also supplies the necessary thrust to the heated air towards the users 11.

The control of the heat exchange inside the heat exchanger 16 is carried out by an electronic control unit 22, integrated in the stove 12, to which a first sensor 23 and a second sensor 24 transmit the electrical signals relating to the temperature measurement. of the air respectively inside the return section 20 and the delivery section 21, i.e. upstream and downstream of the heat exchanger 16. The first sensor 23 therefore measures the temperature Ti of the air entering the fan 15 , which in fact corresponds to the temperature of the air in the users 11, and which allows the electronic control unit 22 to constantly compare with a desired Tx temperature set by the user. This comparison is part of a feedback control process of the heating of the utilities 11, operated by the electronic control unit 22. In fact, based on the temperature value Ti, the electronic control unit 22, according to predefined programs and procedures, manages combustion and heat exchange inside the stove 12.

Connected to the electronic control unit 22 are a third sensor 25, which measures the temperature of the water leaving the heat exchange chamber 14, a feed motor 26 for feeding pellets into the combustion chamber 17, a smoke fan 27, for the evacuation of the fumes from the combustion chamber 17, and a fourth sensor 28, which allows to measure the temperature of the fumes leaving the combustion chamber 17.

The electronic control unit 22 is also able to process the electrical signals coming from the third sensor 25 and from the fourth sensor 28 and referred to the temperatures of the water and the fumes respectively, to consequently vary the rotation speed of the smoke fan 27 and of the supply motor 26. In this way, the electronic control unit 22 guarantees the thermal power necessary to generate the desired quantity of heat and maintains a ratio between fuel and comburent suitable for correct combustion.

The same control unit 22 also controls a pump 29, also integrated in the stove 12, arranged upstream of the heat exchange chamber 14 and having the function of forcing the circulation of water, inside a second circuit, or hydraulic circuit 30, from the same heat exchange chamber 14 to the heat exchanger 16 and vice versa.

In particular, the water leaving the heat exchange chamber 14 at a desired temperature Ta, measured by the third sensor 25, is transferred, through a delivery duct 31, to the heat exchanger 16, in which it transfers heat to the air which it passes through it due to the thrust of the fan 15, to heat it. The heat exchange described above allows to obtain a desired temperature Tf of the air passing through the delivery section 21, which depends on the water temperature Ta and the temperature Ti.

The water thus cooled passes through a return pipe 32 and returns, pumped by the pump 29, into the heat exchange chamber 14, to be heated again by the heat of the fumes present in the combustion chamber 17.

The delivery duct 31 and the return duct 32 fluidically connect the second heat exchange means 18 and the heat exchange chamber 14 of the stove 12, and have reduced dimensions, defined by a cross section having a diameter D comparable to the commonly used pipes. in domestic heating systems and falling within a range of values between 16 mm and 37 mm. This reduced size does not affect the overall dimensions of the apparatus 10 and allows these ducts to be arranged also in view, without compromising the aesthetic appearance of the apparatus 10 itself.

The combustion control described above is advantageously operated continuously and Ti is used as a feedback value, so as to allow the electronic unit 22 a constant and prompt response, to avoid transients in which an excessive lowering of temperature occurs in the users. 11.

Furthermore, the control unit 22 is able to continuously compare the temperature Ti with the temperature Tf at the end of the heat exchange measured by the second sensor 25, allowing the electronic control unit 22 to constantly check the operating efficiency of the heat exchanger 16.

The fan 15 is connected to the control unit 22, which is able to vary its rotation speed, to manage the air flow that passes through the heat exchanger 16 and which is consequently distributed to the users 11. The control of the fan 15 depends on the increase in air temperature (Tf-Ti) recorded by the second sensor 25 and makes it possible not to overheat the air intended for the users 11 in an excessive manner, in order to promote optimum comfort therein.

It should be borne in mind that the thermal power required for heating a house of average size is generally between 5 kW and 12 kw.

With the present invention, since the heating and air distribution are separated and spaced from the stove 12, the latter can have reduced dimensions and are compatible with installation in a single domestic environment, such as a room in a house.

In fact, with the present invention, it is no longer necessary for a large combustion chamber to be formed inside the stove 12, capable of heating all the air, nor placing the fan 15 inside it, which, even if of large size and high noise, it is in any case separated and spaced from the stove 12 and from the environment 13 in which it is installed.

Furthermore, with the present invention, the air distribution circuit 19, even if of considerable size, in particular in relation to the diameter of the pipes, generally having a diameter ranging from about 80 mm to about 200 mm, is no longer connected directly at the stove outlet 12 and can be placed, in such a way as to be barely or not at all visible, in an installation area, or housing compartment 35 specially made, possibly acoustically insulated, such as for example a false ceiling obtained in the room 13 in which the stove 12 or other technical compartment is installed.

In particular, according to the present invention, connected to the stove 12, in addition to the discharge of the combustion fumes, only the delivery 31 and return 32 water conduits are provided, which typically have very reduced diameters, dimensions and aesthetic impact.

Therefore, the present invention, by separating the stove 12 and and the air-water heat exchange means, solves the problem of the overall dimensions and noise of the fan 15, which can be easily positioned in the installation area, or housing compartment, 35. It is clear that modifications and / or additions of parts can be made to the apparatus 10 described up to now, without thereby departing from the scope of the present invention.

In particular, in figs. 1 and 2 the second heat exchange means 18 are shown by way of example concentrated in a single position from which the heated air is sent to the different users 11 through the distribution circuit 19.

Instead, in figs. 3 and 4 show variants in which a plurality of second heat exchange means 18 is provided, distributed in the rooms of the different users 11 and fluidically connected, on the water side, or in general liquid, to the heat exchange chamber 14 of the stove 12. In these variants, the basic operating principle is the same as the embodiments described in conjunction with figs. 1 and 2, with a first heat exchange between combustion fumes and water, or liquid in general, at the stove 12, providing, however, to carry out a plurality of heat exchanges located at the different users 11. Each of the second means of heat exchange 18 heats, by means of the local heat exchange with the hot water coming from the stove 12, its own quantity of air which is taken locally from the corresponding room and diffuses it in the same room. In this case, the distribution circuit 19 can be considered locally, for each user 11, as the local air flow entering and leaving the second heat exchange means 18, indicated by the arrows C of figs. 3 and 4.

In fig. 3 shows in particular a variant in which the second heat exchange means 18 are connected, on the water or liquid side, along a circuit 39 in series with each other with respect to the stove 12 and to the relative heat exchange chamber 14.

In fig. 4 illustrates instead the variant in which the different second heat exchange means 18 are each connected, on the water or liquid side, by means of its own delivery and return circuit 49 to the stove 12 and to the relative heat exchange chamber 14, associated with which A special manifold is provided to which the various circuits 49 belong.

It is also clear that, although the present invention has been described with reference to a specific example, a person skilled in the art will certainly be able to realize many other equivalent forms of apparatus 10, having the characteristics expressed in the claims and therefore all falling within the scope protection defined by them.

Claims (10)

CLAIMS 1. Apparatus for the air heating of one or more users (11) connected to it, comprising a heat generator (12) fed with solid fuel, in particular a biomass, having a combustion chamber (17) and first heat exchange means (14) cooperating with said combustion chamber (17), characterized in that said first heat exchange means (14) are configured to effect the heat exchange between the fumes deriving from the combustion of said biomass and a liquid thermovector which flows in said first heat exchange means (14), and that said apparatus for air heating also comprises second heat exchange means (18), of the air-liquid type, external and spaced from said heat generator (12 ), in which air flows to be heated and distributed to said one or more users (11) to be heated, said second heat exchange means (18) being fluidly connected to said first heat exchange means co (14), to heat said air by means of said heated liquid coming from said first heat exchange means (14). 2. Apparatus as in claim 1, characterized in that said second heat exchange means (18) comprise at least one heat exchanger (16) and a first distribution circuit (19), for the circulation of hot air from said heat exchanger heat (16) to said one or more users (11), and vice versa, having at least one delivery section (21) to one or more users (11) and a return section (20) from one or more users ( 11) to direct the air towards said heat exchanger (16), in which a second circuit (30) is also provided, equipped with a delivery duct (31) and a return duct (32), for the circulation of the liquid heated by said first heat exchange means (14) towards said heat exchanger (16), and vice versa. 3. Apparatus as in claim 2, characterized in that said second heat exchange means (18) further comprise air movement means (15) associated with said return section (20) of said first distribution circuit (19), to withdraw said air from said one or more users (11) and push it at least towards said heat exchanger (16). 4. Apparatus as in claim 2 or 3, characterized in that said means for moving the air comprise a fan (15). 5. Apparatus as claimed in one or the other of claims 2 to 4, characterized in that it comprises first means for measuring the temperature (23), associated with said return section (20) and suitable for transmitting an electrical signal relating to the temperature (Ti) of the air in said return section (20), and an electronic control unit (22), inside said heat generator (12), suitable for receiving and processing said electrical signal to carry out a control in biomass combustion feedback, to maintain said temperature (Ti) in a neighborhood of a value set (Tx) by a user. 6. Apparatus as in claim 5, characterized in that it comprises second temperature measuring means (24) associated with said delivery section (21) of said distribution circuit (19) and suitable for transmitting an electrical signal relating to the temperature ( Tf) of the air in said delivery section (21), and an electronic control unit (22), inside said heat generator (12), suitable for receiving and processing said electrical signal to control the quantity of liquid circulating in said second circuit (30), to maintain said temperature (Tf) in an interval suitable to guarantee a suitable comfort in said one or more users (11). 7. Apparatus as in claim 6, characterized in that it comprises third temperature measuring means (24) associated at least with said delivery duct (31) of said second circuit (30) and suitable for transmitting an electrical signal relating to the temperature ( Ta) of said liquid in said delivery duct, and an electronic control unit (22), internal to said heat generator (12), suitable for receiving and processing said electric signal to check the operating conditions of said liquid in said second circuit (30), and in said first heat exchange means (14). 8. Apparatus as in any one of the preceding claims, characterized in that it comprises second heat exchange means (18) concentrated in a single position from which the heated air is sent to one or more users (11). 9. Apparatus as in any one of claims 1 to 7, characterized in that it comprises a plurality of second heat exchange means (18) distributed in the rooms of the different users (11) and fluidically connected to the first heat exchange means (14) ) of the heat generator (12). 10. Method for the air heating of one or more users (11), comprising a first phase in which, in a combustion chamber (17) of a heat generator (12), the combustion of a biomass is carried out, for perform the heat exchange between the fumes deriving from said combustion and a heat transfer fluid, characterized by the fact that in said first phase the heat exchange is carried out between the fumes and a heat transfer liquid that flows inside the first heat exchange means (14 ), internal to said heat generator (12) and cooperating with said combustion chamber (17), and which comprises a second phase in which air to be heated and distributed to said users (11) is made to flow inside second means heat exchange (18), of the air-liquid type, external and spaced from said heat generator (12), and connected fluidly to said first heat exchange means (14), to be heated by said heated liquid coming from said first mez thermal exchange zi (14).