EP1489366B1 - Installation and method for hot water production - Google Patents

Description

The subject of the present invention is a hot water production installation comprising an outer casing, an upper closure plate, a lower closure plate, a burner with an injection device and a combustion chamber comprising smoke tubes arranged in the interior of the chamber. envelope, and at least one tank / exchanger or exchanger disposed within the casing, the inner space of the casing having an upper portion and a lower portion. It relates more particularly to a condensing plant that can be used for central heating and / or production of hot water for domestic, tertiary, industrial or other.

• l'eau sanitaire est stockée à haute température (>60° C) ce qui accroît le confort et évite tout risque de développement bactériens telle que la légionelle;
• les cloisons du réservoir sanitaire ne sont pas directement en contact avec les parties les plus chaudes de la chaudière grâce à la présence du circuit primaire ; ceci évite la formation de calcaire aux points les plus chauds ainsi qu'une dégradation du rendement de la chaudière dans le temps ;
• le réservoir sanitaire est libre de se déformer lors des variations de pressions, ce qui empêche le calcaire de se fixer sur les parois de l'échangeur ;
• le volume d'eau stocké est réduit et permet de répondre uniquement à une demande de pointe; les pertes à l'arrêt sont dès lors trés faibles;
• la surface de chauffe de l'échangeur est importante et le système fonctionne comme un échangeur direct en cas de puisage élevé; le temps de récupération après puisage est très court;
• résistance à la corrosion par l'utilisation de l'acier inoxydable;
• pas d'anode de protection et pas d'entretien.

Among the usual non-condensing boilers, reference is made to a first type of boilers in which the steel exchanger tank containing the sanitary water is immersed in the primary circuit with the heating water. This type of boiler offers many advantages:

• sanitary water is stored at high temperature (> 60 ° C) which increases comfort and avoids any risk of bacterial growth such as legionella;
• the partitions of the sanitary tank are not directly in contact with the hottest parts of the boiler thanks to the presence of the primary circuit; this avoids the formation of limestone at the hottest points as well as a deterioration of the efficiency of the boiler over time;
• the sanitary tank is free to deform during pressure variations, which prevents the limestone from being fixed on the walls of the exchanger;
• the volume of water stored is reduced and can only respond to peak demand; losses at rest are therefore very low;
• the heating surface of the exchanger is important and the system functions as a direct exchanger in the event of high drawdown; the recovery time after drawing is very short;
• corrosion resistance through the use of stainless steel;
• no protective anode and no maintenance.

However, the market is requesting boilers with an increasingly higher yield. This increase in yields results in the use of condensing boilers in which latent heat is recovered from the flue gases. The dew point temperature is of the order of 55 ° C and the condensation is therefore impossible in a boiler permanently maintained at a temperature of at least 60 ° C.

Condensing boilers have been developed to recover maximum energy from the combustion gases. Indeed, when the temperature of the combustion gases falls below about 50 ° C, condensation droplets form on the heat exchanger elements and fall by gravity to the lower zone of the boiler. This condensing liquid is very corrosive and it is therefore avoided to place the burner in the bottom of the boiler because of rapid degradation thereof.

• on prévoit un échangeur de condensation dans la partie supérieure de la chaudière, telle que décrit dans le document de brevet FR 2 821 924 . Dans ce cas, cette zone de condensation est complètement séparée de la zone de combustion par un fond incliné assurant la récupération et l'évacuation des condensats ;
• on dispose le brûleur dans le centre de la chaudière et on prévoit une zone de condensation en dessous du brûleur, telle que décrit et illustré dans le document GB 2 140 138 ;
• on dispose le brûleur en position inversée au-dessus de la chaudière, telle que décrit dans les documents DE 33 29 777 ou DE 36 25 479 . De cette façon, on peut facilement récupérer les condensats, par gravité, dans la partie inférieure de la chaudière.

Several solutions have been proposed:

• a condensation exchanger is provided in the upper part of the boiler, as described in the patent document FR 2 821 924 . In this case, this condensation zone is completely separated from the combustion zone by an inclined bottom ensuring the recovery and evacuation of the condensates;
• the burner is placed in the center of the boiler and a condensation zone is provided below the burner, as described and illustrated in the document GB 2 140 138 ;
• the burner is placed in the inverted position above the boiler, as described in the documents DE 33 29 777 or DE 36 25 479 . In this way, condensates can be easily recovered by gravity in the lower part of the boiler.

It should be noted however that these last two documents do not concern condensing boilers but already illustrate the arrangement of the inverted burner.

Experience has shown that a device made using the technique of the submerged tank (called "annular tank in tank"), commonly used by the applicant, gives very good results from the point of view of exchange and thermal efficiency, such as as already explained above.

This technique involves immersing an annular cylindrical reservoir, which contains domestic hot water, in a second external reservoir which forms the primary circuit. The flue tubes exchange their heat in the primary circuit, which, in turn, exchanges its heat with domestic hot water through the walls of the tank / exchanger at a lower temperature. The primary circuit is, depending on the case, either used for a heating circuit, or remains closed for a strict production of hot water.

By the document US Patent 4426037 a heating system is known for producing hot water for heating and domestic hot water. The installation comprises an outer casing, an upper closure plate, a lower closure plate, a burner with a combustion chamber, and tubes for the passage of flue gases from the combustion chamber, said tubes serving as a heat exchanger. . The casing further comprises a coil in which the domestic water flows to heat it, and connections for connecting it to a central heating circuit.

The combustion chamber divides the envelope into a lower part located below the combustion chamber, the lower part into which the tubes for the passage of fumes extend, and an upper part situated above the combustion chamber. forming a reservoir in which no tube extends for the passage of fumes. The upper part or small volume tank is not heated by the passage of fumes.

The object of the present invention is to combine the advantages related to the so-called "tank in tank" technique with the technique of condensing boilers in order to obtain a thermal installation capable of supplying central heating water as well as the sanitary water in any condition and with a yield close to the theoretical maximum yield.

In order to achieve this goal, the installation object of the present invention is distinguished in that it has the characteristics as specified in the appended claims.

The invention therefore relates to a hot water production installation comprising an outer casing (1), an upper closure plate (2), a lower closure plate (3), a burner (4) with a device injection (5) and combustion chamber (6) comprising rocket tubes (7) arranged in the casing (1) and at least one tank / exchanger or exchanger disposed inside the casing (1). ), the interior space of the envelope having a partition (11) creating in the envelope (1) an upper portion (12) and a lower portion (13),
characterized in that the upper and lower portions (12,13) are a lower chamber (13) and a superimposed upper chamber (12), the upper chamber (12) of which is continuously maintained at a high temperature,
in that said upper and lower chambers (12,13) and the partition wall (11) are traversed by the flue tubes,
in that the partition wall (11) comprises a communication device (23) between the upper and lower chambers (12, 13), and
in that the burner (4) is placed on the upper closure plate (2) so that the flow of fumes is vertically from top to bottom by the flue tubes (7) passing through both chambers (12, 13) constituting the two primary circuits of the installation, the upper chamber (12) working at high temperature, while the lower chamber (13) is operated at low temperature in the fumes condensation zone.

In order to make the invention clearly understood, an example of a practical embodiment will be described below, with the aid of the appended drawing which represents a vertical shot view of a boiler according to the invention.

The figure shows a block diagram of a boiler device according to the invention.

The boiler comprises an outer shell 1, generally cylindrical, comprising an upper closure plate 2 and a lower closure plate 3.

In the illustrated example, it can be seen that against the upper plate 2 is mounted a burner 4 whose injection device 5 extends towards the hash in the axis of a combustion chamber 6.

The lower part of this combustion chamber 6 is connected with a series of flue tubes 7 which extend downwards to the lower closure plate 3. These tubes 7 are configured as heat exchangers, so that to absorb and distribute as much heat as possible from the flue gases.

Below the bottom plate 3 is mounted a chamber 8 for recovering combustion fumes and condensates which have formed on the inner wall of the tubes 7. For this purpose, the chamber 8 is provided with an outlet pipe 9 fumes and a device 10 for recovering and discharging condensates.

According to the invention, the boiler, illustrated in the drawing, is constructed in two parts, separated in height by a partition wall 11 so as to create an upper chamber 12 and a lower chamber 13; these rooms having different operating temperatures. The upper chamber 12 operates at high temperature and has a large volume of water, the lower chamber 13 is operated at low temperature in the condensation zone.

• le retour 16 de la canalisation du chauffage est raccordé à la chambre inférieure 13 ;
• une sortie 17 de cette chambre inférieure 13 est raccordée par l'intermédiaire d'une canalisation 18 à une vanne à trois voies 19 ;
• cette vanne 19 régule la température de l'eau de départ du chauffage; elle agit à cet effet sur le débit d'eau qui traverse la chambre supérieure 12; la canalisation 20 de départ chauffage étant raccordée par un conduit 21 à une sortie 22 de la chambre supérieure 12;
• un passage direct d'eau primaire, entre les chambres 13 et 12, est obtenu grâce à un dispositif de communication 23 des deux circuits primaires; ce dispositif, tel qu'un orifice calibré, est prévu dans la cloison de séparation 11.
• le cas échéant, une boucle de circulation primaire peut être prévue dans la chambre 12 au moyen d'une canalisation (non illustrée) qui renvoie l'eau, éventuellement par l'intermédiaire d'une pompe de circulation, à partir le la partie supérieure de la chambre 12 vers la partie inférieure de cette chambre 12 ;

The two chambers 12, 13 and the partition wall 11 are traversed by the flue gas tubes 7. The chambers 12 and 13 constitute the primary circuits of the installation which contains the water used for central heating. This primary circuit is composed as follows:

• the return 16 of the heating pipe is connected to the lower chamber 13;
• an outlet 17 of this lower chamber 13 is connected via a pipe 18 to a three-way valve 19;
• this valve 19 regulates the temperature of the starting water of the heating; it acts for this purpose on the flow of water through the upper chamber 12; the heating start pipe 20 being connected via a pipe 21 to an outlet 22 of the upper chamber 12;
• a direct passage of primary water, between the chambers 13 and 12, is obtained through a communication device 23 of the two primary circuits; this device, such as a calibrated orifice, is provided in the partition wall 11.
• if necessary, a primary circulation loop may be provided in the chamber 12 by means of a pipe (not shown) which returns the water, possibly via a circulation pump, from the upper part from the chamber 12 to the lower part of this chamber 12;

The return water from the heating system generally enters a temperature of about 30 ° C through the inlet 16 of the lower chamber 13 and is heated a few degrees before exiting either through the outlet 17 to the valve 19, or by the device 23 of the partition 11 in the upper chamber 12. In this upper chamber 12 the water is heated between 60 and 90 ° C before exiting via the valve 19, where it is mixed with the water. about 32 ° C of the pipe 18 for the heating start which requires about 50 ° C. It is therefore understood that the water in the upper chamber 12 will be constantly maintained at temperatures between 60 ° and 80 ° C while that the temperature of the lower chamber 13 will be maintained within a range of a few degrees above the heating return temperature.

Also according to the invention, there is in each of these chambers 12, 13 a tank / exchanger or an internal exchanger, completely immersed in their respective chambers. Thus, there is disposed in the upper chamber 12 a tank / exchanger 14 annular and coaxial with respect to all of the flue tubes 7 and the outer cylindrical casing 1.

In the lower chamber 13 there is a reservoir / exchanger or an exchanger 15 of smaller dimensions relative to the reservoir 14. This reservoir / exchanger 15 is also annular and coaxial with respect to all the flue tubes 7 and to the outer cylindrical shell 1.

• l'entrée d'eau froide se fait par la canalisation 24 qui amène cette eau dans le réservoir/échangeur 15 de la chambre inférieure 13 ;
• cette eau froide est réchauffée par l'échange de chaleur avec les gaz de combustion au travers du circuit d'eau primaire avant de sortir du réservoir/échangeur 15 par une canalisation 25 qui conduit l'eau dans le réservoir/échangeur 14 de la chambre supérieure 12 ;
• par le contact de ce réservoir/échangeur 14 avec l'eau primaire de la chambre 12, l'eau sanitaire est réchauffée à une température supérieure à 60° C avant de sortir par la canalisation 26 d'alimentation en eau chaude sanitaire.

The water contained in these tanks / exchangers 14, 15 is intended for the use of domestic hot water. The circuit of this water is realized in the following way:

• the cold water inlet is through the pipe 24 which brings this water into the tank / exchanger 15 of the lower chamber 13;
• this cold water is heated by the heat exchange with the combustion gases through the primary water circuit before leaving the tank / exchanger 15 through a pipe 25 which conducts the water in the tank / exchanger 14 of the chamber upper 12;
• by contact of this tank / exchanger 14 with the primary water of the chamber 12, the domestic water is heated to a temperature above 60 ° C before exiting through the pipe 26 of domestic hot water supply.

The temperature of the upper chamber 12 is maintained at a uniform temperature, possibly through a primary circulation loop. In heating operation, the two chambers 12, 13 are irrigated by different flow rates of water through the action of the three-way valve 19; the flow rate is maximum in the lower part to promote condensation and limit the increase in temperature. The flow rate in the upper chamber 12 is defined by the position of the three-way valve 19.

The flue gas circuit comprises only one passage through the tubes 7, which simplifies the construction and reduces the bulk.

The upper part with the chamber 12 is maintained at a homogeneous temperature greater than 60 ° C. by a regulating device acting on the three-way valve 19.

The volume of the lower chamber 13 (low temperature) is limited, which reduces the inertia when switching from a high temperature operating mode to a low temperature operating mode.

1. a) Fonctionnement chauffage à haute température :
   • La température de l'eau de retour est de 60° C.
   • La température de l'eau de départ est de 80° C.
   • L'augmentation de température dans la partie inférieure est faible.
   • La température de l'eau primaire dans la chambre supérieure est homogène et égale ou supérieure à 60° C (l'eau chaude sanitaire est donc disponible à tout moment). Résultat d'essais: Charge nominale (Qn) = 39 kW
        Rendement dans l'eau (sur pci) = 99,0 %
        (pci = pouvoir calorifique inférieure)
        Temp. moyenne de la chambre 12 : 77°C.
2. b) Fonctionnement de chauffage à basse température :
   • La température d'eau de retour est de 30° C.
   • La température d'eau de départ est de 50° C.
   • L'augmentation de la température dans la chambre inférieure 13 est faible.
   • La température de l'eau dans la chambre supérieure 12 est homogène et égale à la température désirée de l'eau chaude sanitaire (supérieure à 60° C).
   • La température de départ de 50° C est atteinte grâce au mélange dans la vanne à trois voies 19 d'une partie de l'eau provenant de la chambre inférieure 13 et d'une partie de l'eau provenant de la chambre supérieure 12.
   Résultats d'essais :Charge nominale (Qn) = 39 kW
      Rendement dans l'eau (sur pci) = 107,5 %
      Temp. moyenne de la chambre 12 : 85° C
      30% de charge, T retour = 30° C (directive 92/42/EEC)
      Rendement dans l'eau (sur pci) = 108,6 %
      Temp. moyenne de la chambre 12 : 72° C.
3. c) Fonctionnement en mode : eau chaude sanitaire uniquement :
   • La température de l'eau froide est de 10° C.
   • L'augmentation de température dans la chambre inférieure 13 est faible.
   • L'eau sanitaire passe du réservoir-échangeur inférieur 15 vers le réservoir-échangeur supérieur 14 qui est maintenu à la température désirée de l'eau chaude sanitaire.
   Résultats d'essais : Charge nominale (Qn) = 39,0 kW
      Débit continu, ΔT = 30K
      Rendement dans l'eau (sur pci) = 105,9 %
      Charge nominale (Qn) = 39,0 kW
      Débit continu, ΔT = 50K
      Rendement dans l'eau (sur pci) = 105 %

In order to demonstrate the real benefits in practical operation, tests resulted in the following findings:

1. a) Heating operation at high temperature:
   • The return water temperature is 60 ° C.
   • The temperature of the starting water is 80 ° C.
   • The temperature increase in the lower part is low.
   • The temperature of the primary water in the upper chamber is homogeneous and equal to or greater than 60 ° C (hot water is available at any time). Test result: Nominal load (Qn) = 39 kW
     Yield in water (on pci) = 99.0%
     (pci = lower heating value)
     Temp. average of room 12: 77 ° C.
2. b) Low temperature heating operation:
   • The return water temperature is 30 ° C.
   • The starting water temperature is 50 ° C.
   • The increase in temperature in the lower chamber 13 is low.
   • The temperature of the water in the upper chamber 12 is homogeneous and equal to the desired temperature of the domestic hot water (greater than 60 ° C).
   • The starting temperature of 50 ° C is achieved by mixing in the three-way valve 19 a portion of the water from the lower chamber 13 and a portion of the water from the upper chamber 12.
   Test results: Nominal load (Qn) = 39 kW
   Yield in water (on pci) = 107.5%
   Temp. average of the room 12: 85 ° C
   30% charge, T return = 30 ° C (Directive 92/42 / EEC)
   Yield in water (on pci) = 108.6%
   Temp. average of the room 12: 72 ° C.
3. c) Operation in mode: domestic hot water only:
   • The temperature of the cold water is 10 ° C.
   • The temperature increase in the lower chamber 13 is low.
   • Sanitary water passes from the lower exchanger tank 15 to the upper exchanger tank 14 which is maintained at the desired temperature of the domestic hot water.
   Test Results: Rated Load (Qn) = 39.0 kW
   Continuous flow, ΔT = 30K
   Yield in water (on pci) = 105.9%
   Rated load (Qn) = 39.0 kW
   Continuous flow, ΔT = 50K
   Yield in water (on pci) = 105%

It follows that the hot water production system according to the invention manages to solve the problems posed and to propose a multi-purpose boiler, combining the following advantages: condensation in heating mode and domestic hot water mode, storage d Integrated high-temperature sanitary water (> 60 ° C), high production of domestic hot water.

The condensation mode is reached in heating mode as well as in sanitary mode but also in mixed operation (sanitary + heating).

Heating operation at very low temperature becomes possible, while maintaining the hot water storage at very high temperature.

The boiler according to the invention therefore comprises two primary circuits operated at different temperatures. The part superior operates at high temperature and includes a tank / exchanger for the production of domestic hot water.

The burner is placed at the top of the boiler and the flow of fumes is vertically from top to bottom in an exchanger that passes through the two primary circuits.

The flow rates of water in each of the primary circuits are regulated according to the desired flow temperature.

captions:

1

outer cylindrical envelope

2

upper closing plate

3

lower closing plate

4

burner

5

burner injection device

6

combustion chamber

7

smoke tubes

8

smoke chamber

9

smoke outlet pipe

10

condensate drain

11

partition wall

12

upper Room

13

lower room

14

tank / upper exchanger

15

tank / lower exchanger

16

heating inlet / return

17

lower chamber outlet

18

outlet pipe

19

three way valve

20

ductwork heating

21

pipe

22

upper room exit

23

primary circuit communication device

24

sanitary cold water inlet

25

sanitary water pipeline

26

sanitary hot water outlet

Claims (15)

1. Installation for the production of hot water, comprising an outer shell (1), an upper cover plate (2), a lower cover plate (3), a burner (4) with an injection device (5) and a combustion chamber (6) comprising flue tubes (7) disposed in the shell (1) and at least one tank/exchanger or an exchanger disposed in the interior of the shell (1), the inner space of the shell including a separation plate (11) creating an upper part (12) and a lower part (13) in the shell (1), characterised in that the upper and lower parts (12, 13) consist of a lower chamber (13) and an upper chamber (12) one on top of the other, the upper chamber (12) being kept constantly at high temperature, that the flue tubes pass through the said upper and lower chambers (12, 13) and the separation plate (11), that the separation plate (11) includes a device (23) for communicating between the upper and lower chambers (12, 13) and that the burner (4) is situated on the upper cover plate (2) in such a manner that the flue gases flow vertically from top to bottom via the flue tubes (7) that pass through the two chambers (12, 13) forming the two primary circuits of the installation, the upper chamber (12) working at high temperature, while the lower chamber (13) is operated at low temperature in the flue gas condensation zone.
2. Installation according to claim 1 for heating water for a primary circuit, characterised in that the lower chamber (13) and the upper chamber (12) each have an outlet (17, 22) for the primary circuit.
3. Installation according to any one of the preceding claims, characterised in that the lower chamber (13) contains a tank/exchanger or a lower heat exchanger (15) and that the upper chamber (12), at high temperature, contains an upper tank/heat exchanger (14).
4. Installation according to claim 3, characterised in that the tank/exchanger or lower exchanger (15) and the upper tank/exchanger (14) are connected together via a pipe (25).
5. Installation according to claim 4, characterised in that the lower tank/exchanger (15) has an inlet (24) for the supply of domestic cold water and the upper tank/exchanger (14) has an outlet (26) for the discharge of domestic hot water.
6. Installation according to any one of the preceding claims, characterised in that the flue tube or tubes (7) is/are connected to the combustion chamber (6) and extend as far as the lower cover plate (3), passing through the separation plate (11).
7. Installation according to any one of the preceding claims, characterised in that the lower chamber (13) includes a return inlet (16) for the primary circuit.
8. Installation according to any one of the preceding claims, characterised in that it comprises a three-way valve (19) connected via a pipe to the lower chamber (13) and via a pipe (21) to the upper chamber (12).
9. Installation according to any one of the preceding claims, characterised in that the separation plate (11) includes a device (26) for the passage of an appropriate flow of water from the primary circuit of the lower chamber (13) to that of the upper chamber (12).
10. Installation according to any one of the preceding claims, characterised in that the upper chamber (12) is provided with a circulation loop connecting an outlet in the upper part of this chamber to an inlet in the lower part of this chamber (12).
11. Installation according to any one of the preceding claims, characterised in that the lower cover plate (3) is provided on its lower side with a flue chamber (8) in which the flue tubes (7) end.
12. Installation according to claim 11, characterised in that the flue chamber (8) is provided with an outlet duct (9) for the flue gases and with a pipe (10) for the recovery and discharge of the condensate.
13. Method of producing hot water for heating for a primary circuit and/or domestic hot water by means of an installation according to any one of the preceding claims.
14. Method according to claim 13, characterised in that the water is heated to a temperature of between 60°C and 90°C in the upper chamber (12).
15. Method according to claim 13 by means of an installation according to claim 2 for heating water for a primary circuit, characterised in that the recirculated water from the primary circuit is returned to the lower chamber (13) to be heated and that the two chambers (12, 13) are fed with water at different flow rates.

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