EP4603761A1

EP4603761A1 - Unit comprising a two-stage component for heating water and refrigerant gas

Info

Publication number: EP4603761A1
Application number: EP25157335.8A
Authority: EP
Inventors: Daniela Chiesa; Gianluca Ferrari
Original assignee: Italtherm SpA
Current assignee: Italtherm SpA
Priority date: 2024-02-16
Filing date: 2025-02-12
Publication date: 2025-08-20
Also published as: IT202400003376A1

Abstract

A unit comprises a burner (2) and a component (100) comprising: a frame (1), a chamber (10), a water/fumes exchanger (20), and an evaporator (3); the water/fumes exchanger (20) and the evaporator (3) are arranged in the chamber (10) and are designed to be externally surrounded by fumes generated by the burner (2); the component (100) comprises: a first inlet (11) formed in the frame (1) at correspondence of the water/fumes exchanger (20), a second inlet (12) formed in the frame (1) at correspondence of the evaporator (3), and an outlet (13) for the discharge of an air-fumes flow from the chamber (10) of the component.

Description

The present patent application for an industrial invention relates to a unit comprising a two-stage component for heating water and refrigerant gas. In particular, the field of reference is that of hybrid plants for heating water, comprising a combustion cell and a heat pump.
Classic thermal plants comprising gas thermal generators are known, comprising a combustion cell delimiting a chamber, a mixing device and a burner connected to the mixing device and disposed within the chamber. The combustion cell comprises a first inlet for the entry of external air into the mixing device and a second inlet for the entry of gas into the mixing device. The external air and gas mix in the mixing device before entering the burner, igniting the combustion and generating high-temperature fumes.
The combustion cell of known thermal generators comprises a water/fumes exchanger arranged within the chamber in order to be surrounded externally by the high-temperature fumes produced during combustion. The water/fumes exchanger is designed to be passed through by the water of a household water plant so that the water circulating through the water/fumes exchanger is heated by the high-temperature fumes.
The combustion cell comprises an outlet, connected to the outside of the thermal generator, to allow the exit of fumes produced during combustion to the outside of the thermal generator.
Said classic thermal plants comprising a gas thermal generator are highly polluting and expensive.
Additionally, classic thermal plants comprising a heat pump for heating/cooling a house using refrigerant gas are known. The known heat pumps comprise an evaporator designed to be passed through by refrigerant gas. External air surrounds the evaporator, heating the refrigerant gas.
Hybrid thermal plants comprising both a gas thermal generator and a heat pump are also known. The hybrid plants comprise an additional heat exchanger that allows heating the technical water of a household's technical water plant using the refrigerant gas of the heat pump, in order to avoid, when possible, the use of the thermal generator.
In both hybrid thermal plants and classic heat pump thermal plants, the refrigerant gas of the heat pump is heated only by external air. However, the external air has a temperature that varies continuously throughout the day and depending on the seasons. Therefore, the heating of the refrigerant gas flowing through the evaporator is strongly influenced by external environmental conditions.
Due to the strong dependency on environmental conditions, large volumes of external air are needed, and consequently, large evaporator heat exchange surfaces are required to heat the refrigerant gas using external air. Therefore, known evaporators are bulky and voluminous and require a large amount of space for installation.
Moreover, the various components of these hybrid thermal plants are located in different positions within the house. Thus, the known hybrid devices require complex, long, and cumbersome installation and commissioning operations and require large installation spaces.
ITBO20120458 discloses a thermal plant comprising a combustion cell comprising a water/fumes exchanger designed to be connected to a water plant, and a thermal exchanger comprising an evaporator designed to be connected to the refrigerant gas plant of a heat pump. The combustion cell and the thermal exchanger are in fluid communication with each other through a channel, so that fumes generated by combustion in the combustion cell enter the heat exchanger and heat the refrigerant gas flowing through the evaporator.
EP4056920 discloses a thermal plant comprising a boiler, an evaporator, and a channel connected to the boiler and ending at the evaporator, so that fumes generated by combustion in the boiler surround the evaporator.
FR2547027 discloses a thermal plant comprising a boiler, an evaporator, and a channel connected to the boiler and ending at the evaporator, that is surrounded by fumes generated by combustion.
The plants of ITBO20120458, EP4056920 , and FR2547027 have the drawback that the fumes, flowing through the channel from the combustion cell to the evaporator, cool down. Therefore, the fumes are unable to efficiently heat the evaporator.
EP3361179 discloses a monoblock heating device obtained by integrating a gas boiler and an air-to-water heat pump.
The purpose of the present invention is to overcome the drawbacks of the known art, providing a unit that allows the efficient heating of the refrigerant gas passing through the evaporator, independently of the external air temperature, while simultaneously heating the technical water in the water/fumes exchanger, in order to achieve a great energy efficiency.
Another purpose is to provide a unit that is compact, easy to install and commission, space-saving, and not bulky.
These purposes are achieved in accordance with the invention having the features listed in the appended independent claim 1.
Advantageous embodiments appear from the dependent claims. The unit according to the invention is defined by claim 1.
The advantages of the unit according to the invention are evident, in fact, due to the fact that the water/fumes heat exchanger and the evaporator are arranged within the same chamber of the component, the fumes generated by the burner, after passing through the water/fumes exchanger, also pass through the evaporator, without significant heat loss. The increase in evaporator efficiency allows for the use of smaller exchange surfaces compared to the evaporators of the known art. Therefore, it is possible to create more compact evaporators with smaller size and volumes compared to those of the known technology. As a result, the unit is efficient, compact, and simple to manufacture, install, and maintain.
For greater clarity, the description of the unit according to the invention continues with reference to the attached drawings, which have a non-limiting illustrative purpose, wherein:

Fig. 1 is a schematic lateral view of the unit according to the invention;
Fig. 2 is a schematic lateral view of a variant of the unit according to the invention;
Fig. 3 is a schematic lateral view of a plant comprising the unit of Fig. 2.

With reference to Fig. 1, a unit according to the invention is disclosed, comprising a two-stage component (100) and a burner (2) designed to initiate combustion of gas and external air, so as to generate high-temperature fumes.
The component (100) comprises a frame (1) and a chamber (10) delimited by the frame (1). The burner (2) is optionally arranged inside the chamber (10) of the component. Optionally, the burner (2) is arranged at the bottom of the chamber (10). The chamber (10) is suitable for containing the fumes generated by the burner (2).
The component (100) comprises a water/fumes exchanger (20) arranged inside the chamber (10) of the frame near the burner (2), optionally above the burner (2), to be externally surrounded by the fumes generated by the combustion. The burner (2) is arranged near the water/fumes exchanger (20), more precisely below the water/fumes exchanger (20). The water/fumes exchanger (20) is designed to be passed through water from a water plant, preferably from a technical water plant. The water/fumes exchanger (20) comprises an inlet (20a) configured to be connected to a return circuit of the water plant and an outlet (20b) configured to be connected to a supply circuit of the water plant. The water circulating through the water/fumes exchanger (20) is heated by the high-temperature fumes, generated by the burner (2), that surround the water/fumes exchanger (20). It should be noted that the water/fumes exchanger (20) can be any type of heat exchanger, such as a coil, plate, or tube bundle exchanger.
The component (100) comprises an evaporator (3) arranged within the chamber (10) downstream of the water/fumes exchanger (20), optionally above the water/fumes exchanger (20). The evaporator (3) is configured to be passed through by refrigerant gas from a heat pump plant. The evaporator (3) comprises an inlet (3a) and an outlet (3b).
The water/fumes exchanger (20) and the evaporator (3) are arranged in the same chamber (10) and are designed to be externally surrounded by the fumes generated by the burner (2).
The component (100) comprises:

a first inlet (11) formed in the frame (1) at the correspondence of the water/fumes exchanger (20) and configured to allow the entry of external combustion air and gas into the chamber (10);
a second inlet (12) formed in the frame (1) at the correspondence of the evaporator (3) and intended to allow the entry of external air into the chamber (10);
an outlet (13) for the discharge of an air-fumes flow from the chamber (10) of the component.

Optionally, the first inlet (11) is formed at the bottom of the frame (1) of the component, below the burner (2). Optionally, the second inlet (12) is formed laterally on the frame (1) of the component, near the evaporator (3). Optionally, the outlet (13) is formed at the top of the frame (1) of the component.
A mixture of gas and combustion air enters the chamber (10) through the first inlet (11). The burner (2) ignites combustion, generating an ascending fumes flow. The fumes flow surrounds the water/fumes exchanger (20), heating the water circulating inside the water/fumes exchanger (20). As the fumes flow rises further in the chamber (10), the fumes flow mixes with external air entering from the second inlet (12) and surrounds the evaporator (3), heating the refrigerant gas circulating through the evaporator (3). The air-fumes flow continues to rise and exits through the outlet (13).
Thanks to the fact that the water/fumes exchanger (20) and the evaporator (3) are arranged within the same chamber (10), the fumes generated by the burner (2), after surround the water/fumes exchanger (20), also surround the evaporator (3), without significant heat losses. The increase in evaporator efficiency allows for the use of smaller heat exchange surfaces compared to evaporators of the known art. Therefore, it is possible to create more compact evaporators with smaller size and volumes than known evaporators. As a result, the component is efficient, compact, and easy to manufacture, install, and maintain.
Thanks to the fact that the water/fumes exchanger (20) and the evaporator (3) are within the same chamber (1), it is possible to heat the refrigerant gas circulating in the evaporator using a flow that comprises not only external air but also high-temperature fumes generated by combustion initiated by the burner (2). In this way, thermal energy contained in the fumes produced by combustion, mixed with external air, is used to heat the refrigerant gas, improving the efficiency of a plant comprising the component.
Moreover, the fumes produced by combustion have a higher temperature than external air temperature, which is independent of environmental conditions. Therefore, the air-fumes flow has a higher, more stable, and less variable temperature compared to the external air alone. This increases the efficiency of the evaporator.
It should be noted that, in order to heat the refrigerant gas, the evaporator (3) requires a greater air flow than that needed to heat the water circulating in the water/fumes exchanger (20). Therefore, the fumes flow rising from the burner (2) alone would not have a sufficient flow rate to heat the refrigerant gas flowing through the evaporator (3). Thanks to the second inlet (12) of the component, external air mixes with the fumes flow to create an air-fumes flow with a sufficient flow rate to heat the refrigerant gas circulating through the evaporator (3).
The component according to the invention is two-stage because it allows both the heating of water in the water/fumes exchanger and the heating of refrigerant gas in the evaporator.
Optionally, an intermediate wall (14) is arranged within the chamber (10) of the component between the water/fumes exchanger (20) and the evaporator (3), so as to divide the chamber (10) into a first upper compartment (16), arranged above the intermediate wall (14), and a second lower compartment (17), arranged below the intermediate wall (14).
The water/fumes exchanger (20) and, optionally, the burner (2) are arranged in the second compartment (17), and the first inlet (11) is in communication with the second compartment (17). The evaporator (3) is arranged in the first compartment (16), and the second inlet (12) and the outlet (13) are in communication with the first compartment (16).
The intermediate wall (14) comprises an opening (15) for the passage of the fumes flow from the second compartment (17) to the first compartment (16). Optionally, the intermediate wall (14) is horizontal and has a tapered funnel shape with decreasing dimensions towards the first compartment (16), to channel the fumes flow towards the first compartment (16).
Thanks to the intermediate wall, the fact that the water/fumes exchanger is positioned lower and the evaporator is positioned higher, the fact that the first inlet of the component is lower than the second inlet, and the fact that the outlet is at the top of the frame, an ascending air-fumes flow is created that first surrounds the water/fumes exchanger and then surrounds the evaporator, minimizing the path of these flows and consequently preventing unnecessary heat loss.
With reference to Fig. 2, a variant of the unit according to the invention is disclosed, differing from the unit of Fig. 1 by the following features:

the burner (2) is arranged within coils of the water/fumes exchanger (20);
the first inlet (11) of the component is formed laterally on the frame (1) to allow the intake of combustion air and gas into the burner (2).

With reference to Fig. 3, a plant (200) comprising the unit according to the invention is disclosed. The plant (200) also comprises:

a heat pump plant comprising a compressor (201) with an inlet (201a) connected via piping to the outlet of the evaporator (3) and an outlet (201b);
a gas/water exchanger (202) comprising a first inlet (202a) connected via piping to the outlet (201b) of the compressor and a first outlet (202b) connected via piping to an inlet of the evaporator (3); the gas/water exchanger (202) also comprises a second inlet (202c) and a second outlet (202d) connected to an inlet of the water/fumes exchanger (20);

a technical water plant (203) comprising a return section (203a) connected to the second inlet (202c) of the gas/water exchanger and a supply section (203b) connected to an outlet of the water/fumes exchanger (20); the technical water plant (203) comprises a pump (207) arranged in the return section (203a) to the circulation of the technical water;
optionally, a sanitary water plant (204);
optionally, a technical water/sanitary water exchanger (205) comprising a first inlet (205a) connected to a return section of the sanitary water plant and a first outlet (205b) connected via piping to a supply section of the sanitary water plant; the technical water/sanitary water exchanger (205) comprises a second inlet (205c) connected via piping and a three-way valve (206) to the supply section (203b) of the technical water plant and a second outlet (205d) connected to the return section (203a) of the technical water plant;
an aspiration device (209) comprising one or more fans; said aspiration device (209) is in fluid communication with the unit to supply external air to the unit; more precisely, the aspiration device (209) is in fluid communication with the first and second inlet (11, 12) of the component to allow the intake of external air through the inlets (11, 12) in the component and the outflow of fumes and exhausted air through the outlet (13) of the component.

The refrigerant gas heated by the evaporator (3), and then by the compressor (201), is condensed in the gas/water exchanger (202), releasing heat and thus heating the return water of the technical water plant.
In this way, the refrigerant gas helps preheat the technical water returning from the technical water plant before it reaches the water/fumes exchanger (20). Therefore, the burner (2) will need to supply less energy to heat the technical water, reducing gas consumption and CO2 emissions.
The technical water/sanitary water exchanger (205) and the three-way valve (206) allow the heating of sanitary water. The three-way valve (206) diverts the flow of technical water, heated through the water/fumes exchanger (20), either directly to a household heating system or to the technical water/sanitary water exchanger (205) to heat sanitary water.
Optionally, the plant (200) comprises a mixing unit (208) arranged upstream of the burner (2) of the unit and downstream of the aspiration device (209). The mixing unit (208) comprises a first inlet connected to the aspiration device (209) for the intake of external air into the mixing unit, a second inlet connected to a gas plant (290) for the entry of gas into the mixing unit, and an outlet in communication with the unit, particularly with the first inlet (11) of the component. In this way, external air and gas are premixed before entering the chamber (10) of the component through the first inlet (11). Alternatively, if the mixing unit is absent, the aspiration device (209) and the gas plant (290) are directly connected to the unit.
Although not shown in the figures, the water/fumes exchanger and the evaporator are arranged side by side within the chamber of the component, and the intermediate wall is positioned vertically. Alternatively, the water/fumes exchanger is positioned above the evaporator, and the intermediate wall is arranged horizontally, with decreasing dimensions towards the bottom.
Although not shown in the figures, alternatively, the burner (2) is arranged outside the chamber of the component and is in fluid communication with the first inlet (11) of the component. The first inlet (11) of the component is configured to allow the entry of fumes generated by the burner (2) into the chamber (10). In this case, the aspiration device of the plant is in fluid communication with the burner to provide combustion air to the burner (2). If the plant comprises the mixing unit (208), the aspiration device of the plant is in fluid communication with the mixing unit, and the outlet of the mixing unit is in communication with the burner (2).
Modifications or variations of detail within the scope of a person skilled in the art may be made to the present embodiment of the invention, which, however, fall within the scope of the invention as expressed in the appended claims.

Claims

Unit comprising a component (100) and a burner (2), designed to ignite combustion of gas and external air, so as to generate fumes; said component (100) comprising:
- a frame (1);

- a chamber (10) delimited by the frame (1) and suitable for containing the fumes generated by the burner (2);

- a water/fumes exchanger (20) designed to be passed through by water from a water plant; said water/fumes exchanger (20) comprising an inlet (20a) configured to be connected to a return circuit of the water plant and an outlet (20b) configured to be connected to a supply circuit of the water plant;

- an evaporator (3) configured to be passed through by refrigerant gas from a heat pump plant; said evaporator (3) comprising an inlet (3a) and an outlet (3b);
wherein

the water/fumes exchanger (20) and the evaporator (3) are arranged in the chamber (10) and are designed to be externally surrounded by fumes generated by the burner (2);

said component (100) comprising:
- a first inlet (11) formed in the frame (1) at the correspondence of the water/fumes exchanger (20);

- a second inlet (12) formed in the frame (1) at the correspondence of the evaporator (3) and intended to allow the entry of external air into the chamber (10);

- an outlet (13) for the discharge of an air-fumes flow from the chamber (10) of the component.
Unit according to claim 1, wherein an intermediate wall (14) is arranged in the chamber (10) of the component between the water/fumes exchanger (20) and the evaporator (3) of the component, so as to divide the chamber (10) into a first compartment (16) and a second compartment (17); said intermediate wall (14) comprising an opening (15).
Unit according to claim 2, wherein the first compartment (16) is upper and is arranged above the intermediate wall (14) and the second compartment (17) is lower and is arranged below the intermediate wall (14).
Unit according to claim 2 or 3, wherein the intermediate wall (14) has a tapered funnel shape with decreasing dimensions towards the first compartment (16), so as to direct the fumes flow towards the first compartment (16).
Unit according to anyone of claims from 2 to 4, wherein the water/fumes exchanger (20) is arranged in the second compartment (17) and the first inlet (11) is in communication with the second compartment (17); the evaporator (3) being arranged in the first compartment (16) and the second inlet (12) and the outlet (13) being in communication with the first compartment (16).
Unit according to anyone of the preceding claims, wherein the evaporator (3) is arranged downstream of the water/fumes exchanger (20).
Unit according to anyone of the preceding claims, wherein the outlet (13) is formed at the top of the frame (1) of the component; said second inlet (12) being formed laterally on the frame (1) of the component.
Unit according to anyone of the preceding claims, wherein the burner (2) is arranged in the chamber (10), near the water/fumes exchanger (20); said first inlet (11) being configured to allow the entry of external combustion air and gas into the chamber (10).
Unit according to claim 8, wherein said burner (2) is arranged below the water/fumes exchanger (20) and said first inlet (11) is formed at the bottom of the frame (1).
Unit according to claim 8, wherein the burner (2) is arranged within coils of the water/fumes exchanger (20) and the first inlet (11) is formed laterally on the frame (1).
Unit according to anyone of claims from 1 to 7, wherein said burner (2) is arranged outside the chamber (10) and is in fluid communication with the first inlet (11) of the component; said first inlet (11) of the component being configured to allow the entry of fumes generated by the burner (2) into the chamber (10).
Plant (200) comprising:
- a unit according to anyone of the preceding claims;

- a heat pump plant comprising a compressor (201) comprising an inlet (201a), connected via a pipeline to an outlet of the evaporator (3), and an outlet (201b);

- a gas/water exchanger (202) comprising a first inlet (202a) connected via a pipeline to the outlet (201b) of the compressor and a first outlet (202b) connected via a pipeline to an inlet of the evaporator (3); the gas/water exchanger (202) comprising a second inlet (202c) and a second outlet (202d) connected to an inlet of the water/fumes exchanger (20);

- a technical water plant (203) comprising a return section (203a) connected to the second inlet (202c) of the gas/water exchanger and a supply section (203b) connected to an outlet of the water/fumes exchanger (20);

- an aspiration device (209) comprising one or more fans; said aspiration device (209) being in fluid communication with said unit to supply external air to said unit.
Plant (200) according to claim 12, comprising a mixing unit (208) arranged upstream of the unit and downstream of the aspiration device (209); said mixing unit (208) comprising a first inlet connected to the aspiration device (209), a second inlet connected to a gas plant (290) for the entry of gas into the mixing unit, and an outlet in communication with the unit.