WO2017050812A1

WO2017050812A1 - System for collecting heat from a fireplace installation pipe with a duct for the circulation of heat transfer fluid

Info

Publication number: WO2017050812A1
Application number: PCT/EP2016/072395
Authority: WO
Inventors: Tristan Caroff; Jean LEFORESTIER
Original assignee: Commissariat A L'energie Atomique Et Aux Energies Alternatives
Priority date: 2015-09-23
Filing date: 2016-09-21
Publication date: 2017-03-30
Also published as: FR3041418A1; FR3041418B1

Abstract

The main subject of the invention is a system for collecting heat (1) from a fireplace installation pipe (2) connected to a building heating appliance, comprising a boiling setting pipe (2) and a thermal insulation pipe (3) arranged around at least a portion of the fireplace installation pipe (2). The system further comprises a duct (4) for the circulation of heat transfer fluid (A), which duct is situated between the fireplace installation pipe (2) and the thermal insulation pipe (3), an inlet (5) for heat transfer fluid (A) towards the inside of the circulation duct (4) and an outlet (6) for heat transfer fluid (A) from inside the circulation duct (4), the heat transfer fluid being able to collect heat as it makes it way from the inlet (5) towards the outlet (6).

Description

SYSTEM FOR COLLECTING HEAT FROM A FUMORY CONDUIT WITH A CHANNEL

CIRCULATION OF HEAT TRANSFER FLUID

DESCRIPTION TECHNICAL FIELD

The present invention relates to the general field of the fumisterie, which is particularly concerned by the arrangements relating to flue gas exhaust ducts. More specifically, it relates to the field of heating installations of a building, such as a dwelling or an industrial space, including an individual heating appliance, such as a fireplace, especially with insert, a boiler or a stove. , wood or pellet, also called pellets.

The invention is also concerned with the field of thermal energy recovery on smoke ducts, as well as with the field of conversion of this thermal energy by thermoelectricity.

The invention thus proposes a system for collecting heat from a chimney duct comprising a heat transfer fluid circulation channel, as well as a building comprising such a heat collection system.

STATE OF THE PRIOR ART

In the field of heating appliances, smoke ducts (hereinafter also called "flue pipes"), in particular chimney, boiler and wood stove and pellet stoves, allow the evacuation of combustion fumes. outwards. These hot fumes carry a large amount of heat in the ducts and thus cause a rise in duct temperature. Also, the standard NF DTU 24.1 requires that the flue pipes be thermally insulated at the upper floors of a habitat to avoid any risk of burns of users.

As a result, it results that the upper floors of the habitat do not benefit from the heat available in the flues because of their insulation. There appears to be a need for energy recovery. thermal at the flue gas ducts, and especially in the upper floors of a habitat.

A ducted version of a boiler is already known which makes it possible to distribute heated air in other rooms of a house than the one where the boiler is located. It is based on a system providing air circulation in an air / air heat exchanger inside the boiler which is diffused in pipes by a blower. However, this system does not make it possible to collect the available heat at the flue gas ducts and generates additional electricity consumption.

Moreover, there are solutions for collecting and converting heat energy from industrial fumes into electrical energy using thermoelectric generators, such as that described, for example, in Chinese patent application CN 104 167 956 A, which describes a electric generation system that does not allow the production of hot air and requires water cooling.

Also known other commercial devices for electric generation appa REILS wood heating, such as, for exam ple of the Indigirka Thermofor ^® and CampStove of BioLite ^® which provide a thermoelectric energy recovery system for a system for example, the Smartfan ^® corresponding to a thermoelectric energy recovery system coupled to a wood stove to homogenize the temperature. around the stove with a fan. However, these devices are not intended to collect the heat lost in the exhaust fumes, but only to supply a fan to assist combustion or mix the ambient air. STATEMENT OF THE INVENTION

The invention thus aims to at least partially remedy the needs mentioned above and the disadvantages relating to the achievements of the prior art. The invention thus has, according to one of its aspects, a heat collection system at the level of a chimney duct connected to a heating appliance of a building, comprising:

a smoke duct for exhausting combustion fumes; a thermal insulation duct disposed around at least a portion of the smoke duct,

characterized in that it further comprises:

a heat transfer fluid circulation channel forming a double wall, situated between the said at least one portion of the smoke duct and the thermal insulation duct,

a heat transfer fluid inlet towards the inside of the circulation channel, formed at a first portion of the thermal insulation duct,

an outlet for heat transfer fluid from inside the circulation channel, formed at a second portion of the thermal insulation duct, located at a distance from the first portion of the thermal insulation duct, the heat transfer fluid being adapted to collect heat as it travels from the entrance to the exit.

Thanks to the invention, it may be possible to collect the heat available on the surface of a duct chimney, in particular to be able to distribute it in an area of a building remote from the heater connected to the duct, and in particular in one or more upper floors of the building. Thus, advantageously, with the same amount of combustion material consumed, in particular the same quantity of wood, it may be possible to heat one or more additional zones, in particular one or more additional parts of a habitat, and also of improve the overall efficiency of the heater.

The heat collection system according to the invention may further comprise one or more of the following characteristics taken separately or in any possible technical combinations.

The coolant is preferably chosen to be ambient air. The chimney duct may in particular be a combustion flue of a chimney, including insert, a boiler or stove, wood or pellet.

The thermal insulation duct may in particular correspond to insulating foam or to a double insulating wall.

The first part of the thermal insulation duct may in particular correspond to a first end of the thermal insulation duct situated near the heating apparatus. The second part of the thermal insulation duct may in turn correspond to a second end of the thermal insulation duct located in an upper floor of the building, away from the heater located for example in a lower floor of the building. The first and second parts of the thermal insulation duct can therefore respectively correspond to a first lower portion and to a second upper portion of the thermal insulation duct.

The system may also advantageously comprise means for guiding flow of the coolant towards the outlet, located at least partly in the circulation channel and configured to promote the heat exchange between the coolant and the combustion fumes. duct of smoke.

Advantageously, the means for guiding the heat transfer fluid ensure optimum heat transfer from the heat of the combustion fumes located in the smoke duct to the coolant located in the circulation channel.

Moreover, the means for guiding the coolant can extend around said at least a portion of the duct from the inlet to the outlet.

In addition, the heat transfer fluid guide means may extend in contact with said at least a portion of the smoke duct and in contact with the thermal insulation duct.

Preferably, the means for guiding the coolant comprise fins and / or a helical helix of heat exchange. In addition, the system may include a ventilation device located at the inlet to allow ventilation of the heat transfer fluid entering the circulation channel and promote the flow of heat transfer fluid.

The system may especially further include a thermoelectric device for the autonomous power supply of the ventilation device.

The thermoelectric device may comprise a clamping ring fixed on the smoke duct and a plurality of thermoelectric modules and heat sinks.

In addition, the invention also relates, according to another of its aspects, to a building, characterized in that it comprises:

- a heater,

- A heat collection system as defined above, the smoke duct being connected to the heater.

The building can be of any type, and for example correspond to a habitat or industrial premises.

In particular, the building may have a lower storey and an upper storey, the heating appliance being located at the lower storey and the heat collecting system being at least partly located at the level of the upper storey including the outlet of the heat collection system being located at the level of the upper floor.

The heater may be of any type, and in particular a fireplace, including insert, a boiler or a stove, wood or pellet.

The heat collection system and the building according to the invention may comprise any of the features set forth in the description, taken alone or in any technically possible combination with other features. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood on reading the following detailed description of an example of non-limiting implementation thereof, as well as on examining the schematic and partial figures of the appended drawing. , on which :

FIG. 1 represents, partially and in perspective, an example of a heat collection system according to the invention,

FIG. 2 represents in more detail part P of FIG. 1,

FIG. 3 shows in more detail, in a different orientation, zone Z of FIG. 2,

FIG. 4A schematically illustrates an example of a habitat according to the prior art comprising a heating device, and

FIG. 4B schematically illustrates an example of a dwelling comprising a heating apparatus and the heat collection system according to the invention of FIG. 1.

In all of these figures, identical references may designate identical or similar elements.

In addition, the different parts shown in the figures are not necessarily in a uniform scale, to make the figures more readable.

DETAILED DESCRIPTION OF A PARTICULAR EMBODIMENT It should be noted that in the exemplary embodiment described hereinafter with reference to FIGS. 1, 2, 3 and 4B, the building considered corresponds to a habitat comprising a lower stage E1, in which is located the heater 21, and an upper stage E2, wherein is located at least in part the heat collection system 1 according to the invention. Of course, the invention is applicable to any type of building, including an industrial premises.

In addition, the heater 21 considered here is a wood stove. However, this choice is in no way limiting. In particular, the heater could also be a fireplace, including insert, or a boiler, wood or pellet. In addition, the heat transfer fluid A considered here corresponds to the ambient air of the habitat 20.

Thus, with reference to FIG. 1, there is shown partially and in perspective, an example of a heat collection system 1 according to the invention. In this figure, the dashed lines between the first 3a and second 3b portions of the thermal insulation duct 3 symbolize the continuity of the thermal insulation duct 3 and make it possible to visualize the interior of the thermal insulation duct 3 in which are located the duct 2 and the guide means 7 of the coolant, symbolized by the arrows A in Figure 1. In addition, the guide means 7 are also represented by transparency at the first 3a and second 3b parts of the duct. thermal insulation 3.

Furthermore, FIG. 2 shows in more detail the part P of FIG. 1, to allow a better visualization of the first part 3a of the thermal insulation duct 3, and FIG. 3 represents in more detail, in a different orientation, Z zone of Figure 2, to allow a better visualization of the ventilation device 8 and the thermoelectric device 9.

The heat collection system 1 comprises first of all a smoke duct, or primary flue gas duct 2 since it is directly in contact with the flue gases, for the evacuation of the flue gases, symbolized by the arrows F in FIG. which go up from the heater 21 along the flue 2 towards the outside of the housing 20.

In addition, for the reasons mentioned previously in the prior art and technical background of the invention, the system 1 comprises a thermal insulation conduit 3, for example in the form of a foam insulation or insulating double wall, in particular to ensure thermal insulation of the primary duct 2 in the upper floor (s) of the housing 20. This thermal insulation duct 3 is arranged around a portion of length L, measured in the vertical direction, of the primary flue gas duct 2.

Furthermore, according to the invention, the heat collection system 1 further comprises a hot air circulation channel 4 forming a double wall. This circulation channel 4 is located between the primary flue gas duct 2 and the thermal insulation duct 3.

Inside this circulation channel 4, guiding means 7 in flow of air are provided. These guide means 7 are designed to promote the heat exchange between the air A entering the channel 4 and the combustion fumes F of the primary flue gas duct 2.

In this example, the guiding means 7 take the form of a helical helix extending all around the length portion L of the primary flue gas duct 2, from an inlet of air towards the interior of the circulation channel. 4 to an outlet 6 of air from inside the circulation channel 4.

Advantageously, this helical helix 7 extends all around the length portion L of the primary flue gas duct 2, in contact with it and in contact with the thermal insulation duct 3.

Furthermore, as can be seen in Figures 1 to 3, the inlet 5 is formed at a first portion 3a of the thermal insulation duct 3, forming a first lower end 3a of the thermal insulation duct 3 , while the outlet 6 is formed at a second portion 3b of the thermal insulation duct 3, forming a second upper end 3b of the thermal insulation duct 3, opposite the first lower end 3a.

Advantageously, the air flowing from the inlet 5 to the outlet 6 collects the heat from the combustion fumes F during its journey.

Moreover, as can be seen in FIG. 1, the outlet 6 comprises, for example, a ventilation grille to allow the hot air A to be vented out of the circulation channel 4, in order to warm the room. in which this hot air outlet 6 is located. Furthermore, as can be seen in FIGS. 1 to 3, the heat collection system 1 comprises, at the air inlet, a ventilation device in the form of a fan 8 to allow a ventilation of the air entering the circulation channel 4 and promote its flow to the outlet 6.

The fan 8 can be powered energetically by the traditional power grid. However, in this embodiment and advantageously, the heat collection system 1 comprises a thermoelectric device 9 to allow autonomous supply of the fan 8.

As can better be seen in FIG. 3, this thermoelectric device 9 comprises a clamping ring 10 fixed on the primary flue 2 and a plurality of thermoelectric modules and heat sinks 11 to enable the conversion of the thermal energy into electric energy. This clamping ring 10 advantageously corresponds to a ring for connecting flat thermoelectric modules on a circular surface, namely that of the flue gas duct 2.

The thermoelectric modules are coupled to the heat sinks 11, thus allowing an optimal thermal exchange between the heat transmitted by the primary flue gas duct 2 to the ambient air by natural convection. The clamping of the heat sinks 11 can be achieved by means of thermal glue or by means of clamping screws.

The thermoelectric material used by the thermoelectric device 9 may be of different types, and in particular chosen from bismuth telluride (III) of formula Bi ₂ Te 3, which has better performances in the range 100-250 ° C., silicon-germanium (SiGe) or other silicides (of the MgSi, MgSiSn, MnSi, ... type), skutterudites and Half-Heusler, among others.

Referring now to FIGS. 4A and 4B respectively, the comparison will be made between a dwelling 20 comprising a heating apparatus 21 connected to a flue 2 'according to a conventional installation according to the DTU 24.1 standard, partially covered by a duct thermal insulation 3 ', and a housing 20 comprising a heater 21 connected to a flue 2 of a heat collection system 1 according to the invention, similar to that described above with reference to FIGS. 3.

For each case of FIGS. 4A and 4B, the housing 20 comprises a lower floor E1 in which the heating appliance 21 is located, and for which the ambient temperature T1 is hot, benefiting from the heat generated by the heating appliance 21 , and an upper stage E2 crossed by the flue gas duct 2 'or 2. The heater 21 is selected here to be a 10 kW wood stove, generating between 5 and 10 g / s of combustion fumes at a temperature of the order of 250 ° C. The fan 8 is a fan type PC, with a power of between 3 and 5 W and an air flow of about 0.5 m ³ / min. This fan 8 is fed by the thermoelectric device 9, of 150 cm ² , clamped on the primary flue gas duct 2 at 200 ° C with a power output of about 4 W.

With regard to the housing example 20 according to the invention, and as can be seen in FIG. 4B, the air inlet A in the circulation channel 4 of the heat collection system 1 is advantageously located in the first lower end 3a of the thermal insulation duct 3, in the immediate vicinity of the heating apparatus 21. This inlet 5 is provided with the fan 8 which makes it possible to blow the air inside the circulation channel 4. Furthermore, the hot air outlet 6 is formed in the second upper end 3b of the thermal insulation duct 3, at the level of the upper stage E2 in order to heat it up.

Advantageously, the presence of the heat collection system 1 in the example of FIG. 4B makes it possible to obtain an ambient temperature T1, for example of the order of 25 ° C. with an outside temperature T _ex t at habitat of about 5 ° C, the upper stage E2, thanks to the hot air A leaving the circulation channel 4 at a temperature of about 35 ° C, which is identical or close to that obtained at the level of lower stage E1 since the heat transported by the flue 2, with temperatures typically between 200 and 350 ° C, is recovered at the outlet 6.

On the contrary, in the habitat 20 according to the prior art of FIG. 4A devoid of any heat recovery system, the ambient temperature T2, for example of the order of 10 ° C. with an outside temperature T _ex t at about 5 ° C, at the level of the upper stage E2 is cold, well below the temperature T1, of the order of 25 ° C, obtained at the lower stage E1, since the insulation the flue gas duct 2 'through the thermal insulation duct 3' prevents heat recovery from the flue gases. Considering that the length L of the portion of the primary flue 2, between the inlet 5 and the outlet 6 and in which the guide means 7 extend, is of the order of 2 m, then the amount of heat collected is of the order of 1 kW, which allows to warm the room of the upper floor E2. It is thus possible to obtain an overall energy gain of the order of 10%.

Therefore, the heat collection system 1 according to the invention allows a better distribution of the heat coming from the heater 21 between the floors of the habitat 20. It also makes it possible to maximize the efficiency of the heating appliance. Heating 21. For example, an improvement of about 10% in the gross heating efficiency on a wood heating system is obtained. The improvement in yield then allows a reduction of greenhouse gas emissions. In addition, the invention implements a heat exchange with the combustion fumes without, however, causing the circulation of combustion fumes in the housing 20.

Of course, the invention is not limited to the embodiment which has just been described. Various modifications may be made by the skilled person.

Claims

Heat collecting system (1) at a chimney duct (2) connected to a heater (21) of a building (20), comprising:

- a smoke duct (2) for the evacuation of combustion fumes (F),

- a thermal insulation duct (3) disposed around at least a portion of the duct duct (2),

characterized in that it further comprises:

- a heat transfer fluid circulation channel (4) (A) forming a double wall, located between said at least a portion of the smoke duct (2) and the thermal insulation duct (3),

an inlet (5) of coolant (A) towards the interior of the circulation channel (4) formed at a first portion (3a) of the thermal insulation duct (3),

an outlet (6) of heat transfer fluid (A) from inside the circulation channel (4), formed at a second portion (3b) of the thermal insulation duct (3), located at a distance from the first part (3a) of the thermal insulation duct (3), the coolant being able to collect heat during its path from the inlet (5) to the outlet (6).

2. System according to claim 1, characterized in that it further comprises guide means (7) in flow of the coolant (A) to the outlet (6), located at least partly in the circulation channel ( 4) and configured to promote the heat exchange between the coolant (A) and the combustion fumes (F) of the smoke duct (2).

3. System according to claim 2, characterized in that the guide means (7) of the coolant (A) extend around said at least a portion of the smoke duct (2) from the inlet (5) until at the exit (6).

4. System according to claim 2 or 3, characterized in that the guide means (7) of the coolant (A) extend in contact with said at least a portion of the duct duct (2) and in contact with the duct thermal insulation (3).

5. System according to any one of claims 2 to 4, characterized in that the guide means (7) of the heat transfer fluid (A) comprise fins and / or a helical helix heat exchange.

6. System according to any one of the preceding claims, characterized in that it further comprises a ventilation device (8) located at the inlet (5) to allow ventilation of the heat transfer fluid (A) entering the circulation channel (4) and promote the flow of heat transfer fluid (A).

7. System according to claim 6, characterized in that it further comprises a thermoelectric device (9) for the autonomous power supply of the ventilation device (8).

8. System according to claim 7, characterized in that the thermoelectric device (9) comprises a clamping ring (10) fixed on the smoke duct (2) and a plurality of thermoelectric modules and heat sinks (11).

9. Building (20), characterized in that it comprises:

- a heater (21),

- A heat collection system (1) according to any one of the preceding claims, the smoke duct (2) being connected to the heater (21).

10. Building according to claim 9, characterized in that it comprises a lower stage (E1) and an upper stage (E2), the heating apparatus (21) being located at the level of the lower stage (E1) and the heat collection system (1) being at least partly located at the upper stage (E2), in particular the outlet (6) of the heat collection system (1) being located at the level of the upper stage (E2).

11. Building according to claim 9 or 10, characterized in that the heater (21) is a fireplace, including insert, a boiler or stove, wood or pellet.