EP4209720A1

EP4209720A1 - A hybrid boiler

Info

Publication number: EP4209720A1
Application number: EP22460082.5A
Authority: EP
Inventors: Tomasz Siemienczuk; Mariusz Kuzma; Katarzyna Ronewicz
Original assignee: AIC Sp zoo
Current assignee: AIC Sp zoo
Priority date: 2022-01-05
Filing date: 2022-12-29
Publication date: 2023-07-12
Also published as: PL440087A1; PL244327B1

Abstract

A hybrid boiler comprises a fired pipe heat exchanger encased in an internal jacket (9), a pipe coil (7) encased in an external jacket (1) which on the one side is closed with a lid (12) incorporating a burner plate, and on the opposite side is closed with a condensate tray (4), water inlet (3) and outlet (11) stub pipes and flue gas exhaust stub pipe (5). Between the external jacket (1) and the internal jacket (9) there is a longitudinal partition (8) separating the internal space between the said jackets (1, 9) into two chambers which are connected to each other below the lid (12), and the chamber formed between the longitudinal partition (8) and the internal jacket (9) is connected to the chamber inside the internal jacket (9) above the condensate tray, where placed in the chamber between the external jacket (1) and the longitudinal partition (8) is a pipe coil (7) fitted with a cooling agent inlet stub pipe (10) and cooling agent outlet stub pipe (2), and the water inlet stub pipe (3) is connected to the said chamber formed between the external jacket (1) and the longitudinal partition (8), whereas the water outlet stub pipe (11) is connected to the chamber formed within the internal jacket (9).

Description

The invention concerns a hybrid boiler, applicable especially in central heating and/or domestic water installations.
Known from patent document EP 3 643 994 A1 is a heat pump boiler which comprises a compressor for compressing a refrigerant, an exterior heat exchanger that is configured to allow heat exchange between a flowing refrigerant and exterior air, an interior heat exchanger that is configured to allow heat exchange between a flowing refrigerant and heating water, a channel change valve that is configured to send the refrigerant compressed by the compressor to the exterior heat exchanger or the interior heat exchanger, a first boiler heat exchanger that is configured to heat heating water that has passed through the interior heat exchanger, using combustion heat, a second boiler heat exchanger that is configured to allow heat exchange between a flowing refrigerant and gas discharged from the first boiler heat exchanger, and a defrosting valve that is configured to send a flowing refrigerant to the interior heat exchanger or the second boiler heat exchanger. Heat pump and boiler can work separately or together.
Known from patent document GB 2503781 A1 is a hybrid heat pump boiler system which comprises a water tank unit, a boiler unit, and an indoor and outdoor unit that together form a heat pump. The outdoor unit has a compressor to compress a refrigerant, a 4-way valve to change a flow-path of the refrigerant discharged from the compressor, a first heat exchanger to allow refrigerant from the 4-way valve to pass through and exchange thermal energy with water from the water tank unit, a first expansion valve to expand refrigerant from the first heat exchanger during a water and space heating operation, and a fan coil unit to receive refrigerant from the first expansion valve. The boiler unit has a heat pipe connected with an exhaust gas recovery heat exchanger. The heat pipe may pass thermal energy captured from the boiler unit to the outdoor units fan coil unit when defrosting of the coil is required, for example, in winter, and has a second expansion valve which may be used with the indoor unit to cool an interior space.
Known from patent document PL 234 215 B1 is a hybrid pellet boiler with an air source heat pump, composed of an air source heat pump, heat exchanger, flue gas exhaust conduit, biomass burning chamber with a pellet burner, hot water tank, biomass container, air intake and exhaust vents, and control module. The air source heat pump and pellet boiler are placed in a common casing.
Known from patent document WO 2013/141728 A2 is a dual purpose heat exchanger comprises a central heating fluid circuit and hot utility water circuit. The exchanger contains fired or heated by flow of water or steam main heat exchanger and coil enclosed by an external jacket equipped with an inlet stub pipe for fluid heating the utility water in the coil as well as an inlet stub pipe and outlet stub pipe for utility water, however, the flow chamber of fluid heating the utility water in the coil is connected with the flow chamber of heated fluid in the main exchanger. The coil is wound on the jacket of the main exchanger, and the flow chamber of fluid heating the utility water in the coil is connected through at least one overflow hole with the flow chamber of heated fluid in the main exchanger.
In known solutions, used in hybrid devices are separate heat exchangers in which the cooling agent condenses, following which the heat obtained as the result of condensation of hot vapours of the cooling agent is, in the form of water heat energy, transmitted for further heating or mixing with water heated by the condensing boiled.
The purpose of this invention is to develop a structure of a hybrid boiler in which water is heated simultaneously using two heat sources, namely a heat pump and condensing boiler, where both water heating processes take place in a single device and can function in compatibility as a single facility heating system.
The described invention solves the problem of increasing the efficiency of the share of renewable energy source compared to the known systems, in particular such in which a gas boiler is the sole source of heat, and obtaining the maximum possible efficiency by simultaneous heating of water using two sources of heat. The hybrid boiler is intended to supplement the energy which the heat pump is unable to generate, where the performance and power depend on external conditions (climate).
According to this invention, a hybrid boiler containing a fired pipe heat exchanger encased in an internal jacket, a pipe coil encased in an external jacket which on the one side is closed with a lid incorporating a burner plate, and on the opposite side is closed with a condensate tray, water inlet and outlet stub pipes and flue gas exhaust stub pipe is characterised in that in between the external jacket and the internal jacket there is a longitudinal partition separating the internal space between the said jackets into two chambers which are connected to each other below the lid, and the chamber formed between the longitudinal partition and the internal jacket is connected to the chamber inside the internal jacket above the condensate tray, where placed in the chamber between the external jacket and the longitudinal partition is a pipe coil fitted with a cooling agent inlet and outlet stub pipes, and the water inlet stub pipe is connected to the said chamber formed between the external jacket and the longitudinal partition, whereas the water outlet stub pipe is connected to the chamber formed within the internal jacket.
Preferably, the boiler is fitted with an additional water inlet stub pipe connected to the chamber within the internal jacket and/or preferably is fitted with an additional water outlet stub pipe connected to the chamber formed between the external jacket and the longitudinal partition.
Thanks to the placement of the coil pipe for the cooling agent within the hybrid boiler, both water heating processes take place in a single device and are able to function in compatibility as a single facility heating system. The solution according to the described invention enables increasing boiler efficiency and minimising heat losses.
The invention in its embodiments is shown on a drawings, where:

Fig. 1 presents the hybrid boiler in axial section, in a perspective view, with water circulation and cooling agent circulation marked thereon;
Fig. 2 shows the hybrid boiler in axial section, in a perspective view, with water circulation in the chamber between the external jacket and the longitudinal partition, and cooling agent circulation marked thereon;
Fig. 3 presents the hybrid boiler in axial section, in a perspective view, with water circulation in the chamber within the internal jacket marked thereon.

According to the first embodiment of the invention, as in Fig. 1, the hybrid boiler incorporates a fired pipe heat exchanger encased in an internal jacket 9, a coil pipe 7 encased in an external jacket 1, the latter closed with a lid 12 with a burner plate on the one side, and with a tray 4 for the condensate on the other side, and further incorporates a water inlet stub pipe 3, water outlet stub pipe 11, and flue gas exhaust stub pipe 5. The fired heat exchanger incorporates a burning chamber 13 with a sieve bottom 14, and a pack of flue gas pipes 6 which on the one side are fitted in the sieve bottom 14 of the burning chamber 13, and on the other side in the sieve bottom 15 positioned above the tray 4 for the condensate. To intensify heat exchange, the flue gas pipes 6 are fitted in the transverse sieve partitions 16 located between the said sieve bottoms 14, 15, along the length of the flue gas pipes. The internal jacket 9 encases the pack of flue gas pipes 6 and the burning chamber 13. Inside the internal jacket 9 there is a water chamber, placed inside of which are the said flue gas pipes 6 and the burning chamber 13. Between the external jacket 1 and the internal jacket 9 there is a longitudinal partition 8 which divides the space between the said jackets 1, 9 into two chambers connected to each other below the lid 12, for example by way of openings 17 made in the longitudinal partition 8 or by way of a slot (slots) positioned between the lid 12 and the longitudinal partition 8. On the other hand, the chamber formed between the longitudinal partition 8 and the internal jacket 9 is connected to the chamber within the internal jacket 9 above the tray 4 for the condensate above the sieve bottom 15, for example by way of openings 18 made in the internal jacket 9 or by way of a slot (slots) between the internal jacket 9 and the sieve bottom 15. Placed in the chamber between the external jacket 1 and the longitudinal partition 8 is a coil pipe 7 spirally coiled along the longitudinal partition 8 and the external jacket 1, fitted with an inlet stub pipe 10 and outlet stub pipe 2 for the cooling agent of the heat pump. The water inlet stub pipe 3 is connected to the said chamber formed between the external jacket 1 and the longitudinal partition 8, while the water outlet stub pipe 11 is connected to the chamber formed within the internal jacket 9 and is placed in the lid 12.
Moreover, shown on Fig. 1 is a water inlet stub pipe 19 to supply water into the chamber within the internal jacket 9, and a water outlet stub pipe 20 to discharge water from the chamber between the external jacket 1 and the longitudinal partition 8, where the said stub pipes 19, 20 in this embodiment are closed, or the hybrid boiler may be devoid of them all together.
The circulation of water in the hybrid boiler is as follows. Water flows through the inlet stub pipe 3 placed in the bottom part of the boiler into the chamber between the external jacket 1 and the longitudinal partition 8 and pressure forces its transport up towards the lid 12, where water flows around the hot spiral coil pipe which contains hot cooling agent supplied through the inlet stub pipe 10 and discharged through the outlet stub pipe 2, and where the cooling agent flows in countercurrent with respect to the water flowing around the coil pipe. Then, once the water reaches the lid 12, it flows through the openings 17 in the longitudinal partition 8 into the chamber between the longitudinal partition 8 and the internal jacket 9 and flows down, flowing against the hot internal jacket 9 and then through the openings 18 made in the bottom part of the internal jacket 9 into the chamber within the internal jacket 9, where inside the chamber there are flue gas pipes 6 and the burning chamber 13. The water flows up towards the lid 12, in countercurrent with respect to the direction of flow of the flue gases, flowing around the hot flue gas pipes 6 and the burning chamber 13, whereupon it leaves the hybrid boiler through the outlet stub pipe 11.
If the hybrid boiler features the water inlet stub pipe 19 which supplies water to the chamber within the internal jacket 9 and/or the water outlet stub pipe 20 which discharges water from the chamber between the external jacket 1 and the longitudinal partition 8, then the stub pipes in the above embodiment are closed.
According to the second invention embodiment, the hybrid boiler described in embodiment one is fitted with a water inlet stub pipe placed above the sieve wall 15, connected to the chamber within the internal jacket 9, and with a water outlet stub pipe 20 placed below the openings 17 in the longitudinal partition 8, connected to the chamber formed between the external jacket 1 and the partition 8.
In this embodiment variant, there are two water circulation routes, as follows. Water flows through the inlet stub pipe 19 placed above the sieve bottom 15 into the chamber within the internal jacket 9, and pressure forces its transport up towards the lid 12, where water flows around the flue gas pipes 6 and the burning chamber 13 and then leaves the hybrid boiler through the outlet stub pipe 11, as shown in Fig. 3. At the same time, water flows through the inlet stub pipe 3 into the chamber between the external jacket 1 and the longitudinal partition 8, where pressure forces its flow around the hot coil pipe 7, whereupon water leaves the hybrid boiler through the outlet stub pipe 20. The coil pipe 7 contains hot cooling agent supplied through the inlet stub pipe 10 and discharged through the outlet stub pipe 2, where the agent flows in countercurrent with respect to the direction the water flowing around the coil pipe, as shown in Fig. 2.
Depending on the needs, it is also possible to achieve only one of the water circulation routes described above.
In all embodiments the coil pipe serves as a condenser in the heat pump circulation cycle. Once the heat is transmitted to water, the condensed cooling agent leaves the hybrid boiler and is transported for evaporation and reintroduction to the compressor.
In the cooling function, the coil pipe may play the role of a heat pump evaporator.

List of numerical references

1 - external jacket
2 - outlet stub pipe of the cooling agent
3 - water inlet stub pipe supplying water to the chamber between the external jacket and the longitudinal partition
4 - condensate tray
5 - flue gas exhaust stub pipe
6 - flue gas pipes
7 - coil pipe
8 - longitudinal partition
9 - internal jacket
10 - cooling agent inlet stub pipe
11 - water outlet stub pipe discharging water from the chamber within the internal jacket
12 - lid with a burner plate
13 - burning chamber
14 - sieve bottom of the burning chamber
15 - sieve bottom above the condensate tray
16 - sieve partitions
17 - openings in the longitudinal partition
18 - openings in the external jacket
19 - water inlet stub pipe supplying water to the chamber within the internal jacket
20 - water outlet stub pipe discharging water from the chamber between the external jacket and the longitudinal partition

Claims

A hybrid boiler containing a fired pipe heat exchanger encased in an internal jacket, a pipe coil encased in an external jacket which on the one side is closed with a lid incorporating a burner plate, and on the opposite side is closed with a condensate tray, water inlet and outlet stub pipes and flue gas exhaust stub pipe characterised in that between the external jacket (1) and the internal jacket (9) there is a longitudinal partition (8) separating the internal space between the said jackets (1, 9) into two chambers which are connected to each other below the lid (12), and the chamber formed between the longitudinal partition (8) and the internal jacket (9) is connected to the chamber inside the internal jacket (9) above the condensate tray, where placed in the chamber between the external jacket (1) and the longitudinal partition (8) is a pipe coil (7) fitted with a cooling agent inlet stub pipe (10) and cooling agent outlet stub pipe (2), and the water inlet stub pipe (3) is connected to the said chamber formed between the external jacket (1) and the longitudinal partition (8), whereas the water outlet stub pipe (11) is connected to the chamber formed within the internal jacket (9).
The boiler according to Claim 1, characterized in that it is fitted with a water inlet stub pipe (19) connected to the chamber within the internal jacket.
The boiler according to Claims 1 or 2, characterized in that it is fitted with a water outlet stub pipe (20) connected to the chamber formed between the external jacket (1) and the longitudinal partition (8).